deltasup 18osub pdb: Topics by WorldWideScience.org

Sample records for deltasup 18osub pdb

Isotopic variations ({delta}{sup 13} C and {delta}{sup 18} O) in Siderastrea stellata (Cnidaria-Anthozoa), Itamaraca island, State of Pernambuco, Northeastern Brazil

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Ferreira, Valderez P.; Sial, Alcides N. [Pernambuco Univ., Recife, PE (Brazil). Dept. de Geologia. Lab. de Isotopos Estaveis; Mayeal, Elga M.; Exner, Marco Antonio [Pernambuco Univ., Recife, PE (Brazil). Dept. de Zoologia. Lab. de Macro e Megabentos

1998-12-01

Isotopic determinations for O and C were performed in coral skeletons collected in beach rocks from two localities (Orange and Catuama), Itamaraca Island, north littoral of the State of pernambuco, northeastern Brazil. Large variations of {delta}{sup 18} O and {delta}{sup 13} C in corals from both localities are found, the largest ones being observed at the Orange locality {delta}{sup 13} C in this locality varies from -0.8 to +1.8% PDB and {delta}{sup 1.8} O from -5.3 to -1.8% PDB, while at the Catuama locality, they vary from -1.8 to 0.1% PDB and -3.8 to -2.7% PDB, respectively. Large variations in {delta}{sup 18} O (up to 2.5%) coupled with weakly defined positive correlation between {delta}{sup 18} O and {delta}{sup 13} C, can be attributed to temperature variations as consequence of climatic perturbations. Temperature estimates, calculated from {delta}{sup 18} O values, assuming isotopic equilibrium with seawater, yield values between 24.9 deg C and 43.1 deg C at Orange, and from 28.4 deg C to 35 deg C at Catuama, all of them (expect one growth band from one sample) are high enough for the full development of the coral colony. Temperature average is 31.4 deg C at Orange, which is a little bit higher than that at Catuama, but both of them indicate thermal stress conditions. In all analyzed specimens, expect for one, at Orange, T increases was accompanied by decreasing in the organic activity, as suggested by corresponding negative {delta}{sup 13} C anomaly. Therefore, the observed bleaching is possibly related to thermal stress and the high T may be related to the El Nino-Southern Oscillation (ENSO) warning event. On the other hand, anthropogenic action at Orange, local of intense tourism throughout the year, coupled with high rate of sedimentation in the region, may contribute to the observed coral bleaching. (author)
Controls of {delta}{sup 34}S and {delta}{sup 18}O in dissolved sulphate: Learning from a detailed survey in the Llobregat River (Spain)

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Otero, Neus [Departament Cristal . lografia, Mineralogia i Diposits Minerals, Facultat de Geologia, Universitat de Barcelona, Marti i Franques, s/n, 08028 Barcelona (Spain); Grup d' Hidrogeoquimica, Departament de Geologia Ambiental, Institut de Ciencies de la Terra ' Jaume Almera' , CSIC, Lluis Sole i Sabaris, s/n, 08028 Barcelona (Spain)], E-mail: notero@ub.edu; Soler, Albert; Canals, Angels [Departament Cristal . lografia, Mineralogia i Diposits Minerals, Facultat de Geologia, Universitat de Barcelona, Marti i Franques, s/n, 08028 Barcelona (Spain)

2008-05-15

The S and O isotopic composition of dissolved SO{sub 4}, used as a tracer for SO{sub 4} sources, was applied to the water of the Llobregat River system (NE Spain). The survey was carried out at 30 sites where surface water was sampled on a monthly basis over a period of 2a. The concentration of dissolved SO{sub 4} varied from 20 to 1575 mg L{sup -1}. Sulphur isotopic compositions clustered in two populations: one - 93% of the samples - had positive values with a mode of +9 per mille ; the other had negative values and a mode of -5 per mille . Data for {delta}{sup 18}O{sub SO{sub 4}} showed a mean value of +11 per mille , with no bi-modal distribution, though lower values of {delta}{sup 18}O corresponded to samples with negative {delta}{sup 34}S. These values can not be explained solely by the contribution of bedrock SO{sub 4} sources: that is, sulphide oxidation and the weathering of outcrops of sulphates, though numerous chemical sediments exist in the basin. Even in a river with a high concentration of natural sources of dissolved SO{sub 4}, such as the Llobregat River, the {delta}{sup 34}S values suggest that dissolved SO{sub 4} is controlled by a complex mix of both natural and anthropogenic sources. The main anthropogenic sources in this basin are fertilizers, sewage, potash mine effluent and power plant emissions. Detailed river water sampling, together with the chemical and isotopic characterisation of the main anthropogenic inputs, allowed determination of the influence of redox processes, as well as identification of the contribution of natural and anthropogenic SO{sub 4} sources and detection of spatial variations and seasonal changes among these sources. For instance, in the Llobregat River the input of fertilisers is well marked seasonally. Minimum values of {delta}{sup 34}S are reported during fertilization periods - from January to March - indicating a higher contribution of this source. The dual isotope approach, {delta}{sup 34}S and {delta}{sup 18}O
Unexpected {delta}{sup 18}O and {delta}{sup 2}H Variability of Groundwater in the Eastern Paris Basin

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Gourcy, L.; Petelet-Giraud, E. [BRGM Service EAU, Orleans (France)

2013-07-15

The Paris Basin covers about one-third of the total surface area of France. In 2009, two campaigns sampling 25 boreholes tapping Tertiary aquifers were carried out in the Basin. These aquifers are recharged at a similar altitude and the groundwater age is too young to have registered climate change. In the past, regional studies included the use of isotopes to understand groundwater origin and dynamics. Both {delta}{sup 18}O and {delta}{sup 2}H as well as ages (CFC/SF{sub 6)} and chemical components were determined in all collected samples. A noticeable stable isotope 'anomaly' appears in the south-western part of the Basin, where the average {delta}{sup 18}O and {delta}{sup 2}H values are more depleted and do not fit the pattern given by the continental effect in this area. A regional particularity of the spatial distribution of such isotopes in precipitation may be possible, but should be confirmed by additional work. (author)
Validation of an O-18 leaf water enrichment model

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Jaeggi, M.; Saurer, M.; Siegwolf, R.

2002-03-01

The seasonal trend in {delta}{sup 18}O{sub ol} in leaf organic matter of spruce needles of mature trees could be modelled for two years. The seasonality was mainly explained by the {delta}{sup 18}O of top-soil water, whereas between years differences were due to variation in air humidity. Application of a third year's data set improved the correlation between modelled and measured {delta}{sup 18}O{sub ol} and thus validated our extended Dongmann model. (author)
Diagenesis and reservoir quality evolution of palaeocene deep-water, marine sandstones, the Shetland-Faroes Basin, British continental shelf

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Mansurbeg, H. [Department of Earth Sciences, Uppsala University, Villavaegen 16, SE 752 36 Uppsala (Sweden); Morad, S. [Department of Earth Sciences, Uppsala University, Villavaegen 16, SE 752 36 Uppsala (Sweden); Department of Petroleum Geosciences, The Petroleum Institute, P.O. Box 2533, Abu Dhabi (United Arab Emirates); Salem, A. [Faculty of Education at Kafr El-Sheikh, Tanta University, Kafr El-Sheikh (Egypt); Marfil, R.; Caja, M.A. [Departmento Petrologia y Geoquimica, Facultad de Geologia, UCM, 28040 Madrid (Spain); El-ghali, M.A.K. (Geology Department, Al-Fateh University, P.O. Box 13696, Libya); Nystuen, J.P. [Department of Geosciences, University of Oslo, P.O. Box 1047 Blindern, NO-0316 Oslo (Norway); Amorosi, A. [Department of Earth Sciences, University of Bologna, Via Zamboni 67, 40127 Bologna (Italy); Garcia, D. [Centre SPIN, Department GENERIC, Ecole Nationale Superieure des Mines de Saint Etienne 158, Cours Fauriel 42023, Saint-Etienne (France); La Iglesia, A. [Instituto de Geologia Economica (CSIC-UCM), Facultad de Geologia, UCM, 28040 Madrid (Spain)

2008-06-15

The Palaeocene, deep-water marine sandstones recovered from six wells in the Shetland-Faroes Basin represent lowstand, transgressive and highstand systems tract turbiditic sediments. Mineralogic, petrographic, and geochemical analyses of these siliciclastics are used to decipher and discuss the diagenetic alterations and subsequent reservoir quality evolution. The Middle-Upper Palaeocene sandstones (subarkoses to arkoses) from the Shetland-Faroes Basin, British continental shelf are submarine turbiditic deposits that are cemented predominantly by carbonates, quartz and clay minerals. Carbonate cements (intergranular and grain replacive calcite, siderite, ferroan dolomite and ankerite) are of eogenetic and mesogenetic origins. The eogenetic alterations have been mediated by marine, meteoric and mixed marine/meteoric porewaters and resulted mainly in the precipitation of calcite ({delta}{sup 18}O{sub V-PDB}=-10.9 permille and -3.8 permille), trace amounts of non-ferroan dolomite, siderite ({delta}{sup 18}O{sub V-PDB}=-14.4 permille to -0.6 permille), as well as smectite and kaolinite in the lowstand systems tract (LST) and highstand systems tract (HST) turbiditic sandstone below the sequence boundary. Minor eogenetic siderite has precipitated between expanded and kaolinitized micas, primarily biotite. The mesogenetic alterations are interpreted to have been mediated by evolved marine porewaters and resulted in the precipitation of calcite ({delta}{sup 18}O{sub V-PDB}=-12.9 permille to -7.8 permille) and Fe-dolomite/ankerite ({delta}{sup 18}O{sub V-PDB}=-12.1 permille to -6.3 permille) at temperatures of 50-140 and 60-140 C, respectively. Quartz overgrowths and outgrowth, which post- and pre-date the mesogenetic carbonate cements is more common in the LST and TST of distal turbiditic sandstone. Discrete quartz cement, which is closely associated with illite and chlorite, is the final diagenetic phase. The clay minerals include intergranular and grain replacive
Spatio-temporal distributions of delta>18O, delta D and salinity in the Arabian Sea: Identifying processes and controls

Digital Repository Service at National Institute of Oceanography (India)

Deshpande, R.D; Muraleedharan, P.M.; Singh, R.L.; Kumar, B.; Rao, M.S.; Dave, M.; Sivakumar, K.U.; Gupta, S.K.

the geographic distributions of the delta>18O and S; (2) in spite of a large scatter, a statistically significant delta>18O–S relationship can be identified in much of the investigated part of the AS; (3) the delta>18O– delta...
Effects of elevated ozone on leaf {delta}{sup 13}C and leaf conductance of plant species grown in semi-natural grassland with or without irrigation

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Jaeggi, M. [Agroscope FAL Reckenholz, Swiss Federal Research Station for Agroecology and Agriculture, Air Pollution/Climate Group, CH-8046 Zurich (Switzerland)]. E-mail: maya.jaeggi@psi.ch; Saurer, M. [Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Volk, M. [Agroscope FAL Reckenholz, Swiss Federal Research Station for Agroecology and Agriculture, Air Pollution/Climate Group, CH-8046 Zurich (Switzerland); Fuhrer, J. [Agroscope FAL Reckenholz, Swiss Federal Research Station for Agroecology and Agriculture, Air Pollution/Climate Group, CH-8046 Zurich (Switzerland)

2005-03-01

Stable carbon isotope ratios ({delta}{sup 13}C) and leaf conductance (g{sub s}) were measured (2002, 2003) in Holcus lanatus L., Plantago lanceolata L. Ranunculus friesianus (Jord.), and Trifolium pratense L. at two levels of ozone (O{sub 3}) with or without irrigation. In non-irrigated control plots, R. friesianus showed the least negative {delta}{sup 13}C, and the smallest response to the treatments. Irrigation caused more negative {delta}{sup 13}C, especially in H. lanatus. Irrespective of irrigation, O{sub 3} increased {delta}{sup 13}C in relationship to a decrease in g{sub s} in P. lanceolata and T. pratense. The strongest effect of O{sub 3} on {delta}{sup 13}C occurred in the absence of irrigation, suggesting that under field conditions lack of moisture in the top soil does not always lead to protection from O{sub 3} uptake. It is concluded that in species such as T. pratense plants can maintain stomatal O{sub 3} uptake during dry periods when roots can reach deeper soil layers where water is not limiting. - Under natural field conditions, lack of precipitation may not protect semi-natural vegetation from O{sub 3} effects on leaf gas exchange.
The dynamics of central Main Ethiopian Rift waters: Evidence from {delta}D, {delta}{sup 18}O and {sup 87}Sr/{sup 86}Sr ratios

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Rango, Tewodros, E-mail: tewodros.godebo@duke.edu [Division of Earth and Ocean Sciences, Nicholas School of the Environment, Duke University, Durham, NC 27708 (United States)] [Addis Ababa University, Department of Earth Sciences, P.O. Box 1176, Addis Ababa (Ethiopia); Petrini, Riccardo; Stenni, Barbara [University of Trieste, Department of Geosciences, Via Weiss 1, I-34100 Trieste (Italy); Bianchini, Gianluca [Istituto di Geoscienze e Georisorse-CNR, Pisa (Italy)] [Department of Earth Sciences, University of Ferrara, Via Saragat 1, 44100 Ferrara (Italy); Slejko, Francesca [University of Trieste, Department of Geosciences, Via Weiss 1, I-34100 Trieste (Italy); Beccaluva, Luigi [Department of Earth Sciences, University of Ferrara, Via Saragat 1, 44100 Ferrara (Italy); Ayenew, Tenalem [Addis Ababa University, Department of Earth Sciences, P.O. Box 1176, Addis Ababa (Ethiopia)

2010-12-15

Research highlights: {yields} Chemical and isotope ({delta}D, {delta}{sup 18}O and {sup 87}Sr/{sup 86}Sr) techniques are applied to understand various hydrological processes in the Main Ethiopian Rift. {yields} Some of the studied groundwaters display a depleted {delta}D-{delta}{sup 18}O composition when compared to the present-day average precipitation, thus suggesting that the rift floor aquifers also contains paleo-meteoric waters recharge associated with deep flow system. {yields} The pristine waters coming from the highlands display isotopic compositions characterized by less radiogenic {sup 87}Sr/{sup 86}Sr (and more depleted {delta}D, {delta}{sup 18}O). This isotopic signature subsequently evolves towards higher {sup 87}Sr/{sup 86}Sr by an interaction with the more radiogenic rhyolites of the rift and their weathered and redeposited products. - Abstract: Water samples from cold and geothermal boreholes, hot springs, lakes and rivers were analyzed for {delta}D, {delta}{sup 18}O and {sup 87}Sr/{sup 86}Sr compositions in order to investigate lake water-groundwater mixing processes, water-rock interactions, and to evaluate groundwater flow paths in the central Main Ethiopian Rift (MER) of the Ziway-Shala basin. Different ranges of isotopic values were recorded for different water types: hot springs show {delta}{sup 18}O -3.36 to +3.69 and {delta}D -15.85 to +24.23, deep Aluto-Langano geothermal wells show {delta}{sup 18}O -4.65 to -1.24 and {delta}D -12.39 to -9.31, groundwater wells show {delta}{sup 18}O -3.99 to +5.14 and {delta}D -19.69 to +32.27, whereas the lakes show {delta}{sup 18}O and {delta}D in the range +3.98 to +7.92 and +26.19 to +45.71, respectively. The intersection of the Local Meteoric Water Line (LMWL: {delta}D = 7 {delta}{sup 18}O + 11.2, R{sup 2} = 0.94, n = 42) and the Local Evaporation Line (LEL: {delta}D = 5.63{delta}{sup 18}O + 8, n = 14, R{sup 2} = 0.82) was used to estimate the average isotopic composition of recharge water into the
Oxygen isotope variations in phosphate of biogenic apatites. Pt. 2. Phosphorite rocks

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Kolodny, Y; Luz, B; Shemesh, A [Hebrew Univ., Jerusalem (Israel). Dept. of Geology

1983-09-01

Phosphorites from sedimentary sequences ranging in age from Archaen to Recent were analysed for delta/sup 18/O in both the PO/sub 4/ (delta/sup 18/Osub(p)) and CO/sub 3/ (delta/sup 18/Osub(c)) in the apatite lattice. The oxygen isotope record is considerably better preserved in phosphates than in either carbonates or cherts. The use of the Longinelli and Nuti temperature equation yields temperatures for Recent phosphorites that are in good agreement with those measured in the field. The delta/sup 18/Osub(p) values of ancient phosphorites decrease with increasing age. These changes with time are not likely to be due to post-depositional exchange. Changes in delta/sup 18/O values of seawater and variations of temperatures with time can account for the delta/sup 18/Osub(p) time trend, but the latter explanation is preferred. In Ancient phosphorites delta/sup 18/Osub(c) in structurally bound carbonate in apatite is not a reliable geochemical indicator.
Environmental isotopes (N, S, C, O, D) to determine natural attenuation processes in nitrate contaminated waters: Example of Osona (NE Spain)

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Vitoria, Laura [Grup de Mineralogia Aplicada i Medi Ambient, Departament de Cristal.lografia, Mineralogia i Diposits Minerals, Facultat de Geologia, Universitat de Barcelona, Marti i Franques, s/n, 08028, Barcelona (Spain)], E-mail: lvitoria@ub.edu; Soler, Albert; Canals, Angels [Grup de Mineralogia Aplicada i Medi Ambient, Departament de Cristal.lografia, Mineralogia i Diposits Minerals, Facultat de Geologia, Universitat de Barcelona, Marti i Franques, s/n, 08028, Barcelona (Spain); Otero, Neus [Grup de Mineralogia Aplicada i Medi Ambient, Departament de Cristal.lografia, Mineralogia i Diposits Minerals, Facultat de Geologia, Universitat de Barcelona, Marti i Franques, s/n, 08028, Barcelona (Spain); Departament de Geologia Ambiental, Institut de Ciencies de la Terra ' Jaume Almera' , CSIC C/Lluis Sole i Sabaris s/n, Barcelona 08028 (Spain)

2008-12-15

Nitrate-contaminated groundwater from an aquifer in the Osona region (NE Spain) was chemically and isotopically ({delta}{sup 15}N{sub NO{sub 3}},{delta}{sup 18}O{sub NO{sub 3}},{delta}{sup 34}S{sub SO{sub 4}},{delta}{sup 18}O{sub SO{sub 4}}, {delta}D, {delta}{sup 18}O{sub H{sub 2}}{sub O} and {delta}{sup 13}C{sub DIC}) characterized. Diffuse- NO{sub 3}{sup -} contamination reached values of 366 mg/L. Nearly 75% of the 37 sampled sites had higher concentrations than the 50 mg/L in NO{sub 3}{sup -} limit for drinking water. To identify the source of pollution {delta}{sup 15}N{sub NO{sub 3}} and {delta}{sup 18}O{sub NO{sub 3}} were used with results, for most samples, in the range of pig manure NO{sub 3}{sup -}. Nitrification processes were evaluated by means of the {delta}{sup 18}O of NO{sub 3}{sup -} and water. Isotopic data suggested that natural attenuation of NO{sub 3}{sup -} was taking place. This process was confirmed using the {delta}{sup 18}O{sub NO{sub 3}} coupled with the NO{sub 3}{sup -}/Cl{sup -} ratio, avoiding the influence of continuous NO{sub 3}{sup -} inputs. A further insight on denitrification processes was obtained by analyzing the ions involved in denitrification reactions. Although the role of organic matter oxidation could neither be confirmed nor discarded, this approach showed a link between denitrification and pyrite oxidation. Therefore, in areas with no adequate infrastructure (e.g. multipiezometers), such as the one studied, this approach could be useful for implementing better water management.
Multivariate analysis of calcareous nanno fossils and stable isotopic ({delta}{sup 18}O and {delta}{sup 13}C) in the upper Campanian - lower Maastrichtian of the Campos Basin, Brazil; Analise multivariada em nanofosseis calcarios e isotopos estaveis ({delta}{sup 18}O e {delta}{sup 13}C) do Campaniano superior - Maastrichtiano inferior na Bacia de Campos

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Oliveira, Luiz Carlos Veiga de [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas. Gerencia de Bioestratigrafia e Paleoecologia]. E-mail: lcveiga@petrobras.com.br; Rodrigues, Rene; Lemos, Valesca Brasil

2005-05-01

Qualitative analysis in calcareous nanno fossils is a powerful tool for bio stratigraphic uses, principally in identification of bio zones and determination of relative age. But quantitative studies must be applied for pale oceanographic applications and high resolution bio stratigraphy. In order to better understand the relationships between the different species of nanno fossils, new methodologies and non-traditional correlation tools were tested on a 18 m upper Campanian - lower Maastrichtian core from Campos Basin. Multiple regression helped to determine the best counting method. Watznaueria barnesae and Micula decussata dominate the fossil assemblage and have inverse abundances to each other. Both were opportunist species in competition for nutrients. Q mode factorial analysis (57 samples, 19 variables) was applied to the same core and shows that two factors explain 99.2% of the total variance of the micro fossil assemblage. The first factor represents 83.6% and the second factor only 15.6% of the total variance. The former is associated with Watznaueria barnesae, Cribrosphaerella ehrenbergii and Stradneria crenulata, which represent the original population of nano plankton. The latter factor is associated with Micula decussata, which is believed to represent the effect of solution at the sediment water interface. Both factors were used to develop a dissolution-sea level curve for nanno fossils. When combined with oxygen and carbon isotopes, this curve clearly shows that higher dissolution occurred during the late Campanian - early Maastrichtian time when {delta}{sup 18}O, {delta}{sup 13} C and TOC all had lower values. These correlations indicate a strong link between high sea levels, high temperatures and lower amount of continental organic debris. (author)
{delta}{sup 13}C in Tibetan juniper trees - climate trends through the past 1600 years; {delta}{sup 13}C in tibetischen Wacholdern - Klimaentwicklung der letzten 1600 Jahre

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Zimmermann, B.

1998-09-01

A {delta}{sup 13}C{sub Zell}-chronology of juniper tree cellulose from the upper treeline covering the last 1600 years was set up. The tree site is situated close to Qamdo in southeast Tibet at an altitude of 4350 m a.s.l. The southwest slope gets rain during the Indian summer monsoon. Ten trees have been sampled either by coring or by cutting of trunc-sections in pentad sampling interval. Three trees were analysed in two different radial directions. The very positive {delta}{sup 13}C{sub Zell}-data generally varying around -18,75 permille show the typical low fractionation of high mountain plants. Different interpretations are suggested for data before and after 1800 A.D. (orig.) [Deutsch] An Zellulose von Wacholdern der oberen Waldgrenze in Suedost-Tibet wurde eine 1600-jaehrige {delta}{sup 13}C{sub Zell}-Chronologie aufgestellt. Der Standort liegt in 4350 m ue.M. in der Naehe von Qamdo, ist nach Suedwest geneigt und erhaelt Niederschlaege in den Sommermonaten durch den Indischen-Suedwest-Monsun. Zehn Baeume wurden anhand von Kernen und Stammscheiben in Abschnitten von fuenf Jahren beprobt. An drei Baeumen konnten zwei Segmente desselben Baumes untersucht werden. Die im Mittel sehr positiven {delta}{sup 13}C{sub Zell}-Daten um -18,75 permille deuten auf eine fuer Hochgebirgspflanzen typische geringere Fraktionierung hin. Unterschiedliche Interpretationswege werden fuer die Daten vor und nach 1800 verfolgt. (orig.)
The Oxygen Isotopic Composition of Phosphate: A Tracer for Phosphate Sources and Cycling

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Mclaughlin, K. [Southern California Coastal Water Research Project, Costa Mesa, University of California, CA (United States); Young, M. B.; Paytan, A.; Kendall, C. [U.S. Geological Survey, University of California, CA (United States)

2013-05-15

Phosphorus (P) is a limiting macro-nutrient for primary productivity and anthropogenic P-loading to aquatic ecosystems is one of the leading causes of eutrophication in many ecosystems throughout the world. Because P has only one stable isotope, traditional isotope techniques are not possible for tracing sources and cycling of P in aquatic systems. However, much of the P in nature is bonded to four oxygen (O) atoms as orthophosphate (PO{sub 4}{sup 3-}). The P-O bonds in orthophosphate are strongly resistant to inorganic hydrolysis and do not exchange oxygen with water without biological mediation (enzyme-mediated recycling). Thus, the oxygen isotopic composition of dissolved inorganic phosphate ({delta}{sup 18}O{sub p}) may be used as a tracer for phosphate sources and cycling in aquatic ecosystems. Recently, several studies have been conducted utilizing {delta}{sup 18}O{sub p} as a tracer for phosphate sources and cycling in various aquatic environments. Specifically, work to date indicates that {delta}{sup 18}O{sub p} is useful for determining sources of phosphate to aquatic systems if these sources have unique isotopic signatures and phosphate cycling within the system is limited compared to input fluxes. In addition, because various processes imprint specific fractionation effects, the {delta}{sup 18}O{sub p} tracer can be utilized to determine the degree of phosphorous cycling and processing through the biomass. This chapter reviews several of these studies and discusses the potential to utilize the {delta}{sup 18}O{sub p} of phosphate in rivers and streams. (author)
Water circulation control on carbonate-{delta}{sup 18}O records in a low permeability clay formation and surrounding limestones: The Upper Dogger-Oxfordian sequence from the eastern Paris basin, France

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Lavastre, Veronique, E-mail: veronique.lavastre@univ-st-etienne.fr [Universite de Lyon, Universite Jean Monnet, F-42023 Saint Etienne (France)] [CNRS, UMR 6524, LMV, F-42023 Saint Etienne (France)] [Laboratoire de Geochimie des Isotopes Stables, Institut de Physique du Globe de Paris and Universite Paris 7 - UMR CNRS 7154, 4, place Jussieu, 75252 Paris cedex 05 (France); Ader, Magali [Laboratoire de Geochimie des Isotopes Stables, Institut de Physique du Globe de Paris and Universite Paris 7 - UMR CNRS 7154, 4, place Jussieu, 75252 Paris cedex 05 (France); Buschaert, Stephane [Andra, Parc de la Croix Blanche, 7-8 rue Jean Monnet, 92 298 Chatenay-Malabry Cedex (France); Petit, Eddy; Javoy, Marc [Laboratoire de Geochimie des Isotopes Stables, Institut de Physique du Globe de Paris and Universite Paris 7 - UMR CNRS 7154, 4, place Jussieu, 75252 Paris cedex 05 (France)

2011-05-15

Research Highlights: > Up. Dog./Oxf. sequence is investigated for radioactive waste disposal feasibilities. > Marine carbonates suffered isotopic exchanges with meteoric water. > Modelling shows that very low W/R ratio can explain isotopic changes in clay layer. > Higher W/R ratio are needed to reach isotopic changes in carbonated layers. > Confirmed barrier property of clay layer was probably reached during early burial. - Abstract: Upper Dogger to Oxfordian Formations in the eastern part of the Paris basin (France) are currently being investigated by the French nuclear waste management agency (Andra), testing the feasibility of long-term deep nuclear waste disposal in the Callovo-Oxfordian claystones. Characterising the hydrogeological behaviour of the Callovo-Oxfordian claystones is, therefore, essential in evaluating its potential as a geological barrier. In order to evaluate and quantify water/rock interactions experienced over geological time by these Formations, bulk carbonate {delta}{sup 13}C and {delta}{sup 18}O were measured and calculations of water-rock ratios were used to explain carbonate-{delta}{sup 18}O changes. Meteoric porewater and a maximum temperature reached of about 40 deg. C were considered. The Jurassic marine carbonate {delta}{sup 13}C was preserved in the Callovo-Oxfordian claystones and in the overlying limestones (-0.28 per mille to 3.39 per mille/PDB), while the {delta}{sup 18}O values are lower by 0-5 per mille (-6.25 per mille to -1.32 per mille/PDB). Calculations show that Upper Dogger and Oxfordian Limestone {delta}{sup 18}O data: (i)have random-like distribution through theoretical {delta}{sup 18}O-W/R curves and (ii)suggest that water/rock ratios (0.08-0.4) needed to explain {delta}{sup 18}O changes are higher by a factor of about 2-20 compared to the present-day water/rock ratio. These features indicate advection in both aquifers. According to the history of the Paris basin, this hydrogeological behaviour could have been
Variability of {sup 10}Be and {delta}{sup 18}O in snow pits from Greenland and a surface traverse from Antarctica

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Berggren, A.-M. [Dept. of Earth Sciences, Uppsala University, Villav. 16, 752 36 Uppsala (Sweden); Aldahan, A., E-mail: ala.aldahan@geo.uu.se [Dept. of Earth Sciences, Uppsala University, Villav. 16, 752 36 Uppsala (Sweden); Dept. of Geology, United Arab Emirates University, P.O. Box 17551 Al Ain (United Arab Emirates); Possnert, G. [Tandem Laboratory, Uppsala University, P.O. Box 529, 751 20 Uppsala (Sweden); Hansson, M. [Dept. of Physical Geography and Quaternary Geology, Stockholm University, 106 91 Stockholm (Sweden); Steen-Larsen, H.C. [Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej, 30,2100 Copenhagen (Denmark); Sturevik Storm, A. [Dept. of Earth Sciences, Uppsala University, Villav. 16, 752 36 Uppsala (Sweden); Moerth, C.-M. [Dept. of Geology and Geochemistry, Stockholm University, 106 91 Stockholm (Sweden); Murad, A. [Dept. of Geology, United Arab Emirates University, P.O. Box 17551 Al Ain (United Arab Emirates)

2013-01-15

To examine temporal variability of {sup 10}Be in glacial ice, we sampled snow to a depth of 160 cm at the NEEM (North Greenland Eemian Ice Drilling) drilling site in Greenland. The samples span three years between the summers of 2006 and 2009. At the same time, spatial variability of {sup 10}Be in glacial ice was explored through collection of the upper {approx}5 cm of surface snow in Antarctica during part of the Swedish-Japanese traverse from Svea to Syowa station during the austral summer in 2007-2008. The results of the Greenlandic {sup 10}Be snow suggested variable concentrations that apparently do not clearly reflect the seasonal change as indicated by the {delta}{sup 18}O data. The {sup 10}Be concentration variability most likely reflects also effects of aerosol loading and deposition pathways, possibly in combination with post-depositional processes. The Antarctic traverse data expose a negative correlation between {sup 10}Be and {delta}{sup 18}O, while there are weaker but still significant correlations to altitude and distance to the coast (approximated by the distance to the 70th latitude). These relationships indicate that geographical factors, mainly the proximity to the coast, may strongly affect {sup 10}Be concentrations in snow in Queen Maud Land, Antarctica.
Preparation of aligned W{sub 18}O{sub 49} nanowire clusters with high photocatalytic activity

Energy Technology Data Exchange (ETDEWEB)

Zhang, Ning [State Key Laboratory of Inorganic Synthesis & Preparative Chemistry, Jilin University, Changchun 130012 (China); Zhao, Yafei, E-mail: zhaoyafei007@126.com [State Key Laboratory of Inorganic Synthesis & Preparative Chemistry, Jilin University, Changchun 130012 (China); School of Chemical Engineering and Energy, Zhengzhou University, Zhengzhou, Henan 450001 (China); Lu, Yanjie [School of Chemical Engineering and Energy, Zhengzhou University, Zhengzhou, Henan 450001 (China); Zhu, Guangshan, E-mail: zhugs@jlu.edu.cn [State Key Laboratory of Inorganic Synthesis & Preparative Chemistry, Jilin University, Changchun 130012 (China)

2017-04-15

Highlights: • Aligned W{sub 18}O{sub 49} nanowire clusters were prepared by a facile hydrothermal method. • W{sub 18}O{sub 49} has unique structure, high degree of crystallinity and large surface area. • W{sub 18}O{sub 49} nanowire clusters exhibited high photocatalytic degradation activity. - Abstract: The aligned W{sub 18}O{sub 49} nanowire clusters were synthesized via a facile and economic ethanol-assisted hydrothermal method using peroxopolytungstic acid as precursor. Results show that the as-prepared W{sub 18}O{sub 49} exhibits a high yield and ultrathin structure with preferential growth direction along [0 1 0]. The amount of peroxopolytungstic acid and reaction time play significant role on the morphology of W{sub 18}O{sub 49} nanowires. The nanowires have unique structure, high degree of crystallinity, large specific surface area, and large number of defects such as oxygen vacancies, which are responsible for their high photocatalytic performance for degradation of methylene blue. The photocatalytic conversion of methylene blue can reach above 98% after degradation. W{sub 18}O{sub 49} also exhibits good photodegradation stability after five cycles of reuse. The results demonstrate that the as-prepared W{sub 18}O{sub 49} nanowire clusters are expected to be a promising material for applications in the field of environment.
Toward a Mechanistic Understanding of Deuterium Excess as a Tracer for Evapotranspiration

Energy Technology Data Exchange (ETDEWEB)

Lai, Chun-Ta [Department of Biology, San Diego State University, San Diego, CA (United States)

2013-07-15

An understanding of atmospheric water vapour and its isotopic composition is useful for modelling effects of terrestrial evapotranspiration on regional hydrologic cycles. Previous studies showed diurnal and vertical patterns of water vapour isotope ratios ({delta}{sup 2}H{sub v} and {delta}{sup 18}O{sub v}) consistently observed in an old growth coniferous forest. Using a box model and a mass balance approach to simulate 'isoflux of d-excess', the effect of evapotranspiration on the d-excess in atmospheric water vapour is quantitatively demonstrated. The results suggest that d-excess can be mechanistically utilized to identify processes that contribute to the diurnal variation in atmospheric moisture. These new findings have implications for larger-scale predictions of precipitation across the terrestrial landscape. In this paper, I report the initial results of the {delta}{sup 2}H{sub v} and {delta}{sup 18}O{sub v} measurements using a cavity enhanced spectroscopy instrument. These recent data are consistent with the pattern observed by the conventional sampling method, providing new opportunities for studying d-excess as a tracer for evapotranspiration. (author)
Stable isotopes and heavy metal distribution in Dreissena polymorpha (Zebra Mussels) from western basin of Lake Erie, Canada

Energy Technology Data Exchange (ETDEWEB)

Al-Aasm, I.S.; Clarke, J.D.; Fryer, B.J. [Windsor Univ., ON (Canada). Dept. of Earth Sciences

1998-02-01

Dreissena polymorpha is an exotic freshwater bivalve species which was introduced into the Great Lakes system in the fall of 1985 through the release of ballast water from European freighters. Utilizing individual growth rings of the shells, the stable isotope distribution ({delta}{sup 18}O and {delta}{sup 13}C) was determined for the life history of selected samples which were collected from the western basin of Lake Erie. These bivalves deposit their shell in near equilibrium with the ambient water and thus reflect any annual variation of the system in the isotopic records held within their shells. Observed values for {delta}{sup 18}O range from -6.64 to -9.46 permille with an average value of -7.69 permille PDB, while carbon values ranged from -0.80 to -4.67 permille with an average value of -1.76 permille PDB. Dreissena polymorpha shells incorporate metals into their shells during growth. Individual shell growth increments were analyzed for Pb, Fe, Mg, Mn, Cd, Cu, and V concentrations. The shells show increased uptake of certain metals during periods of isotopic enrichment which correspond with warmer water temperatures. Since metals are incorporated into the shells, the organism may be useful as a biomonitor of metal pollution within aquatic environments. (orig.)
PDB: CBRC-TNIG-22-0159 [SEVENS

Lifescience Database Archive (English)

Full Text Available 2WBE,3DU7,2E4H, Region:346-770(Identity=93%) PDB:3E22 Chain:A (X-ray Resolution=3.80),Region:346-770(Identity...=95%) PDB:3DCO Chain:A (EM Resolution=1.90),Region:346-770(Identity=95%) PDB:3EDL Chain:A (EM Resolution=28.00),Region:346-770(Ident...ity=94%) PDB:1FFX Chain:A (X-ray Resolution=3.95),Region:346-770(Identity...=94%) PDB:1IA0 Chain:A (EM Resolution=15.00),Region:346-770(Identity=94%) PDB:1JFF Chain:A ...(EM Resolution=3.50),Region:346-770(Identity=94%) PDB:1SA0 Chain:A (X-ray Resolution=3.58),Region:346-770(Identity
Coral skeletal {delta}{sup 15}N reveals isotopic traces of an agricultural revolution

Energy Technology Data Exchange (ETDEWEB)

Marion, Guy S. [Department of Biological Sciences, Stanford University, Stanford, CA 94305 (United States)]. E-mail: g.marion@uq.edu.au; Dunbar, Robert B. [Department of Geological and Environmental Sciences, Stanford University, Stanford, CA 94305 (United States); Mucciarone, David A. [Department of Geological and Environmental Sciences, Stanford University, Stanford, CA 94305 (United States); Kremer, James N. [Department of Marine Sciences, University of Connecticut at Avery Point, Groton, CT 06340 (United States); Lansing, J. Stephen [Department of Anthropology, University of Arizona, Tucson, AZ 85721 (United States); Arthawiguna, Alit [Installation for Agricultural Research (IP 2TP), Kotak Pos 3480, Denpasar, Bali (Indonesia)

2005-09-01

This study introduces a new method of tracing the history of nutrient loading in coastal oceans via {delta}{sup 15}N analysis of organic nitrogen preserved in the skeleton of the massive Porites coral. Four coral cores were collected in Bali, Indonesia, from reefs exposed to high levels of fertilizers in agricultural run-off, from lagoonal corals impacted by sewage, and from a reef located 30 km offshore. Skeletal {delta}{sup 15}N in the agriculturally exposed coral declined from 10.7 {+-} 0.4 per mille in 1970-1971, when synthetic fertilizers (-0.8 per mille {+-} 0.2 per mille ) were introduced to Bali, to a depleted 'anthropogenic' baseline of 3.5 per mille {+-} 0.4% in the mid-1990s. {delta}{sup 15}N values were negatively correlated with rainfall, suggesting that marine {delta}{sup 15}N lowers during flood-born influxes of waste fertilizers. Reef cores exposed to untreated sewage in terrestrial discharge were enriched (7.8 and 7.3 {+-} 0.4 per mille ), while the offshore core reflected background oceanic signals (6.2 {+-} 0.4 per mille). {delta}{sup 15}N, N concentration, and C:N systematics indicate that the N isotopic composition of skeletal organic matter was generally well preserved over 30 years. We suggest that skeletal organic {delta}{sup 15}N can serve as a recorder of past nitrogen sources. In Bali, this tracer suggests that the intensification of Western style agricultural practices since 1970 are contributing to the degradation of coastal coral reefs.

{delta}{sup 15}N of seagrass leaves for monitoring anthropogenic nutrient increases in coral reef ecosystems

Energy Technology Data Exchange (ETDEWEB)

Yamamuro, M.; Kayanne, H.; Yamano, H

2003-04-01

In a coral reef environment, a slight increase in dissolved inorganic nitrogen (DIN;{>=}1.0 {mu}M) can alter the ecosystem via macroalgal blooms. We collected seagrass leaves from the tropical and subtropical Pacific Ocean in five countries and examined the interactions between nutrient concentrations (C, N, P), molar ratios of nutrients, and {delta}{sup 15}N to find a possible indicator of the DIN conditions. Within most sites, the concentrations of nutrients and their molar ratios showed large variations owing to species-specific values. On the other hand, almost identical {delta}{sup 15}N values were found in seagrass leaves of several species at each site. The correlations between {delta}{sup 15}N and nutrient concentrations and between {delta}{sup 15}N and molar ratios of nutrients suggested that nutrient availability did not affect the {delta}{sup 15}N value of seagrass leaves by altering the physiological condition of the plants. Increases in {delta}{sup 15}N of seagrass leaves mostly matched increases in DIN concentrations in the bottom water. We suggest that {delta}{sup 15}N in seagrass leaves can be a good tool to monitor time-integrated decrease/increase of DIN concentrations at a site, both in the water column and the interstitial water.
PDB: CBRC-PTRO-04-0067 [SEVENS

Lifescience Database Archive (English)

Full Text Available 2HPY,2I35,2I36,2I37,2J4Y,3C9M,1RY1,1EDS,1EDV,1EDW,1FDF,1NZS,1VQX, Region:1-348(Identity=93%) PDB:2PED Chain:...A (X-ray Resolution=2.95),Region:1-348(Identity=93%) PDB:3C9L Chain:A (X-ray Resolution=2.65),Region:1-348(Identity...=93%) PDB:3CAP Chain:A (X-ray Resolution=2.90),Region:1-40(Identity=95%) P...DB:1EDX Chain:A (NMR),Region:1-348(Identity=93%) PDB:1F88 Chain:A (X-ray Resolution=2.80),Region:1-348(Identity...=93%) PDB:3DQB Chain:A (X-ray Resolution=3.20),Region:1-348(Identity=93%) PDB:1GZM Chain:A (X-ray Resolut
PDB: CBRC-PABE-04-0004 [SEVENS

Lifescience Database Archive (English)

Full Text Available 2HPY,2I35,2I36,2I37,2J4Y,3C9M,1RY1,1EDS,1EDV,1EDW,1FDF,1NZS,1VQX, Region:1-348(Identity=93%) PDB:2PED Chain:...A (X-ray Resolution=2.95),Region:1-348(Identity=93%) PDB:3C9L Chain:A (X-ray Resolution=2.65),Region:1-348(Identity...=93%) PDB:3CAP Chain:A (X-ray Resolution=2.90),Region:1-40(Identity=95%) P...DB:1EDX Chain:A (NMR),Region:1-348(Identity=93%) PDB:1F88 Chain:A (X-ray Resolution=2.80),Region:1-348(Identity...=93%) PDB:3DQB Chain:A (X-ray Resolution=3.20),Region:1-348(Identity=93%) PDB:1GZM Chain:A (X-ray Resolut
PDB: CBRC-TTRU-01-1321 [SEVENS

Lifescience Database Archive (English)

Full Text Available 2G87,2HPY,2I35,2I36,3C9M,2J4Y,1RY1,1EDS,1EDV,1EDW,1FDF,1NZS,1VQX, Region:1-348(Identity=92%) PDB:2I37 Chain:...A (X-ray Resolution=4.15),Region:1-348(Identity=92%) PDB:2PED Chain:A (X-ray Resolution=2.95),Region:1-348(Identity...=92%) PDB:3C9L Chain:A (X-ray Resolution=2.65),Region:1-348(Identity=92%) ...PDB:3CAP Chain:A (X-ray Resolution=2.90),Region:1-40(Identity=92%) PDB:1EDX Chain:A (NMR),Region:1-348(Identity...=92%) PDB:1F88 Chain:A (X-ray Resolution=2.80),Region:1-348(Identity=92%) PDB:3DQB Chain:A (X-ray Resolut
PDB: CBRC-HSAP-03-0075 [SEVENS

Lifescience Database Archive (English)

Full Text Available 2HPY,2I35,2I36,2I37,2J4Y,3C9M,1RY1,1EDS,1EDV,1EDW,1FDF,1NZS,1VQX, Region:1-348(Identity=93%) PDB:2PED Chain:...A (X-ray Resolution=2.95),Region:1-348(Identity=93%) PDB:3C9L Chain:A (X-ray Resolution=2.65),Region:1-348(Identity...=93%) PDB:3CAP Chain:A (X-ray Resolution=2.90),Region:1-40(Identity=95%) P...DB:1EDX Chain:A (NMR),Region:1-348(Identity=93%) PDB:1F88 Chain:A (X-ray Resolution=2.80),Region:1-348(Identity...=93%) PDB:3DQB Chain:A (X-ray Resolution=3.20),Region:1-348(Identity=93%) PDB:1GZM Chain:A (X-ray Resolut
PDB: CBRC-CPOR-01-1479 [SEVENS

Lifescience Database Archive (English)

Full Text Available 2G87,2HPY,2I35,2I36,3C9M,2J4Y,1RY1,1EDS,1EDV,1EDW,1FDF,1NZS,1VQX, Region:1-354(Identity=88%) PDB:2I37 Chain:...A (X-ray Resolution=4.15),Region:1-354(Identity=88%) PDB:2PED Chain:A (X-ray Resolution=2.95),Region:1-354(Identity...=88%) PDB:3C9L Chain:A (X-ray Resolution=2.65),Region:1-354(Identity=88%) ...PDB:3CAP Chain:A (X-ray Resolution=2.90),Region:1-40(Identity=87%) PDB:1EDX Chain:A (NMR),Region:1-354(Identity...=88%) PDB:1F88 Chain:A (X-ray Resolution=2.80),Region:1-354(Identity=88%) PDB:3DQB Chain:A (X-ray Resolut
PDB: CBRC-RMAC-11-0073 [SEVENS

Lifescience Database Archive (English)

Full Text Available 2HPY,2I35,2I36,2I37,2J4Y,3C9M,1RY1,1EDS,1EDV,1EDW,1FDF,1NZS,1VQX, Region:1-348(Identity=93%) PDB:2PED Chain:...A (X-ray Resolution=2.95),Region:1-348(Identity=93%) PDB:3C9L Chain:A (X-ray Resolution=2.65),Region:1-348(Identity...=93%) PDB:3CAP Chain:A (X-ray Resolution=2.90),Region:1-40(Identity=95%) P...DB:1EDX Chain:A (NMR),Region:1-348(Identity=93%) PDB:1F88 Chain:A (X-ray Resolution=2.80),Region:1-348(Identity...=93%) PDB:3DQB Chain:A (X-ray Resolution=3.20),Region:1-348(Identity=93%) PDB:1GZM Chain:A (X-ray Resolut
PDB: CBRC-CFAM-20-0004 [SEVENS

Lifescience Database Archive (English)

Full Text Available 2HPY,2I35,2I36,2I37,2J4Y,3C9M,1RY1,1EDS,1EDV,1EDW,1FDF,1NZS,1VQX, Region:1-348(Identity=94%) PDB:2PED Chain:...A (X-ray Resolution=2.95),Region:1-348(Identity=94%) PDB:3C9L Chain:A (X-ray Resolution=2.65),Region:1-348(Identity...=94%) PDB:3CAP Chain:A (X-ray Resolution=2.90),Region:1-40(Identity=97%) P...DB:1EDX Chain:A (NMR),Region:1-348(Identity=94%) PDB:1F88 Chain:A (X-ray Resolution=2.80),Region:1-348(Identity...=94%) PDB:3DQB Chain:A (X-ray Resolution=3.20),Region:1-348(Identity=94%) PDB:1GZM Chain:A (X-ray Resolut
PDB: CBRC-OANA-01-1800 [SEVENS

Lifescience Database Archive (English)

Full Text Available 2G87,2HPY,2I35,2I36,3C9M,2J4Y,1RY1,1EDS,1EDV,1EDW,1FDF,1NZS,1VQX, Region:1-353(Identity=89%) PDB:2I37 Chain:...A (X-ray Resolution=4.15),Region:1-353(Identity=89%) PDB:2PED Chain:A (X-ray Resolution=2.95),Region:1-353(Identity...=89%) PDB:3C9L Chain:A (X-ray Resolution=2.65),Region:1-353(Identity=89%) ...PDB:3CAP Chain:A (X-ray Resolution=2.90),Region:1-40(Identity=82%) PDB:1EDX Chain:A (NMR),Region:1-353(Identity...=89%) PDB:1F88 Chain:A (X-ray Resolution=2.80),Region:1-353(Identity=89%) PDB:3DQB Chain:A (X-ray Resolut
PDB: CBRC-PVAM-01-0804 [SEVENS

Lifescience Database Archive (English)

Full Text Available 2HPY,2I35,2I36,2I37,2J4Y,3C9M,1RY1,1EDS,1EDV,1EDW,1FDF,1NZS,1VQX, Region:1-348(Identity=94%) PDB:2PED Chain:...A (X-ray Resolution=2.95),Region:1-348(Identity=94%) PDB:3C9L Chain:A (X-ray Resolution=2.65),Region:1-348(Identity...=94%) PDB:3CAP Chain:A (X-ray Resolution=2.90),Region:1-40(Identity=97%) P...DB:1EDX Chain:A (NMR),Region:1-348(Identity=94%) PDB:1F88 Chain:A (X-ray Resolution=2.80),Region:1-348(Identity...=94%) PDB:3DQB Chain:A (X-ray Resolution=3.20),Region:1-348(Identity=94%) PDB:1GZM Chain:A (X-ray Resolut
PDB: CBRC-GGOR-01-1431 [SEVENS

Lifescience Database Archive (English)

Full Text Available 2HPY,2I35,2I36,2I37,2J4Y,3C9M,1RY1,1EDS,1EDV,1EDW,1FDF,1NZS,1VQX, Region:1-348(Identity=93%) PDB:2PED Chain:...A (X-ray Resolution=2.95),Region:1-348(Identity=93%) PDB:3C9L Chain:A (X-ray Resolution=2.65),Region:1-348(Identity...=93%) PDB:3CAP Chain:A (X-ray Resolution=2.90),Region:1-40(Identity=95%) P...DB:1EDX Chain:A (NMR),Region:1-348(Identity=93%) PDB:1F88 Chain:A (X-ray Resolution=2.80),Region:1-348(Identity...=93%) PDB:3DQB Chain:A (X-ray Resolution=3.20),Region:1-348(Identity=93%) PDB:1GZM Chain:A (X-ray Resolut
PDB: CBRC-FCAT-01-1134 [SEVENS

Lifescience Database Archive (English)

Full Text Available 2HPY,2I35,2I36,2I37,2J4Y,3C9M,1RY1,1EDS,1EDV,1EDW,1FDF,1NZS,1VQX, Region:1-348(Identity=95%) PDB:2PED Chain:...A (X-ray Resolution=2.95),Region:1-348(Identity=95%) PDB:3C9L Chain:A (X-ray Resolution=2.65),Region:1-348(Identity...=95%) PDB:3CAP Chain:A (X-ray Resolution=2.90),Region:1-40(Identity=97%) P...DB:1EDX Chain:A (NMR),Region:1-348(Identity=95%) PDB:1F88 Chain:A (X-ray Resolution=2.80),Region:1-348(Identity...=95%) PDB:3DQB Chain:A (X-ray Resolution=3.20),Region:1-348(Identity=95%) PDB:1GZM Chain:A (X-ray Resolut
PDB: CBRC-HSAP-10-0036 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-HSAP-10-0036 1HLL,1HO9,1HOD,1HOF, Region:118-149(Identity=100%) PDB:1HLL Chain...:A (NMR),Region:118-149(Identity=100%) PDB:1HO9 Chain:A (NMR),Region:118-149(Identity=100%) PDB:1HOD Chain:A (NMR),Region:118-149(Identity=100%) PDB:1HOF Chain:A (NMR), ...
PDB: CBRC-MMUS-19-0098 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-MMUS-19-0098 1HLL,1HO9,1HOD,1HOF, Region:133-164(Identity=100%) PDB:1HLL Chain...:A (NMR),Region:133-164(Identity=100%) PDB:1HO9 Chain:A (NMR),Region:133-164(Identity=100%) PDB:1HOD Chain:A (NMR),Region:133-164(Identity=100%) PDB:1HOF Chain:A (NMR), ...
PDB: CBRC-BTAU-01-1941 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-BTAU-01-1941 1HLL,1HO9,1HOD,1HOF, Region:118-149(Identity=100%) PDB:1HLL Chain...:A (NMR),Region:118-149(Identity=100%) PDB:1HO9 Chain:A (NMR),Region:118-149(Identity=100%) PDB:1HOD Chain:A (NMR),Region:118-149(Identity=100%) PDB:1HOF Chain:A (NMR), ...
PDB: CBRC-CJAC-01-0391 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-CJAC-01-0391 1FFX,1IA0,1JFF,1SA0,1SA1,1TUB,1TVK,2WBE,1Z2B,3DCO,3DU7,3E22, Region:421-804(Identity...=82%) PDB:1FFX Chain:B (X-ray Resolution=3.95),Region:421-804(Identity=82%) PDB:1IA0 Chai...n:B (EM Resolution=15.00),Region:421-804(Identity=82%) PDB:1JFF Chain:B (EM Resolution=3.50),Region:421-804(Identity...=82%) PDB:1SA0 Chain:B (X-ray Resolution=3.58),Region:421-804(Identity=82...%) PDB:1SA1 Chain:B (X-ray Resolution=4.20),Region:421-788(Identity=82%) PDB:1TUB Chain:B (EM Resolution=3.70),Region:421-788(Identit
Synthesis of tungsten oxide (W{sub 18}O{sub 49}) nanosheets utilizing EDTA salt by microwave irradiation method

Energy Technology Data Exchange (ETDEWEB)

Hariharan, V.; Parthibavarman, M. [Centre for Nanoscience and Technology, Department of Physics, Periyar University, Salem 636 011, Tamilnadu (India); Sekar, C., E-mail: Sekar2025@gmail.com [Centre for Nanoscience and Technology, Department of Physics, Periyar University, Salem 636 011, Tamilnadu (India); Department of Bioelectronics and Biosensors, Alagappa University, Karaikudi 630 003, Tamilnadu (India)

2011-04-07

Research highlights: > We have synthesized tungsten oxide (WO{sub 3-{delta}}) nanoparticles by microwave irradiation method for the first time using EDTA as surface modulator. The variation in stoichiometric oxygen content of the annealed samples clearly indicates the role of EDTA in reaction medium. The variation in oxygen content also modified the transparency of the end product confirming the change in optical conductivity. - Abstract: We report the synthesis of crystalline W{sub 18}O{sub 49} with nanosheet like morphology by low cost microwave irradiation method without employing hydrothermal process for the first time. Initially, WO{sub 3}.H{sub 2}O was synthesized using ethylenediaminetetraacetic acid (EDTA) as surface modulator. The product was annealed at 600 {sup o}C for 6 h in ambient atmosphere in order to obtain anhydrous tungsten oxide W{sub 18}O{sub 49}. Powder X-ray diffraction results confirmed the as prepared WO{sub 3}.H{sub 2}O to be orthorhombic and W{sub 18}O{sub 49} to be monoclinic phase, respectively. Transmission electron micrographs (TEM) revealed that the W{sub 18}O{sub 49} nanosheets have the average dimensions of the order of 250 nm in length and around 150 nm in width. UV-visible diffusion reflectance spectroscopic (DRS) studies revealed the band gap energies to be 3.28 and 3.47 eV for WO{sub 3}.H{sub 2}O and W{sub 18}O{sub 49} samples, respectively. The growth mechanism of two dimensional W{sub 18}O{sub 49} nanosheets is discussed.
PDB: CBRC-BTAU-01-2619 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-BTAU-01-2619 1U34,2JNC,2JND, Region:43-137(Identity=85%) PDB:1U34 Chain:A (NMR),Region:43-137(Identity...=85%) PDB:2JNC Chain:A (NMR),Region:43-137(Identity=85%) PDB:2JND Chain:A (NMR), ...
PDB: CBRC-PABE-08-0030 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-PABE-08-0030 1U34,2JNC,2JND, Region:45-139(Identity=85%) PDB:1U34 Chain:A (NMR),Region:45-139(Identity...=85%) PDB:2JNC Chain:A (NMR),Region:45-139(Identity=85%) PDB:2JND Chain:A (NMR), ...
PDB: CBRC-PCAP-01-1657 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-PCAP-01-1657 1U34,2JNC,2JND, Region:43-137(Identity=80%) PDB:1U34 Chain:A (NMR),Region:43-137(Identity...=80%) PDB:2JNC Chain:A (NMR),Region:43-137(Identity=80%) PDB:2JND Chain:A (NMR), ...

PDB: CBRC-CJAC-01-1334 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-CJAC-01-1334 2R4R,2RH1,3D4S,2R4S, Region:32-398(Identity=96%) PDB:2R4R Chain:A... (X-ray Resolution=3.40),Region:32-398(Identity=96%) PDB:2RH1 Chain:A (X-ray Resolution=2.40),Region:32-398(Identity...=96%) PDB:3D4S Chain:A (X-ray Resolution=2.80),Region:55-398(Identity=96%) PDB:2R4S Chain:A (X-ray Resolution=3.40), ...
PDB: CBRC-HSAP-05-0044 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-HSAP-05-0044 2R4R,2RH1,3D4S,2R4S, Region:1-365(Identity=99%) PDB:2R4R Chain:A ...(X-ray Resolution=3.40),Region:1-365(Identity=99%) PDB:2RH1 Chain:A (X-ray Resolution=2.40),Region:1-365(Identity...=99%) PDB:3D4S Chain:A (X-ray Resolution=2.80),Region:24-365(Identity=99%) PDB:2R4S Chain:A (X-ray Resolution=3.40), ...
PDB: CBRC-RMAC-06-0031 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-RMAC-06-0031 2R4R,2RH1,3D4S,2R4S, Region:1-367(Identity=98%) PDB:2R4R Chain:A ...(X-ray Resolution=3.40),Region:1-367(Identity=98%) PDB:2RH1 Chain:A (X-ray Resolution=2.40),Region:1-367(Identity...=98%) PDB:3D4S Chain:A (X-ray Resolution=2.80),Region:24-367(Identity=97%) PDB:2R4S Chain:A (X-ray Resolution=3.40), ...
PDB: CBRC-PTRO-06-0041 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-PTRO-06-0041 2R4R,2RH1,3D4S,2R4S, Region:85-449(Identity=99%) PDB:2R4R Chain:A... (X-ray Resolution=3.40),Region:85-449(Identity=99%) PDB:2RH1 Chain:A (X-ray Resolution=2.40),Region:85-449(Identity...=99%) PDB:3D4S Chain:A (X-ray Resolution=2.80),Region:108-449(Identity=99%) PDB:2R4S Chain:A (X-ray Resolution=3.40), ...
PDB@: an offline toolkit for exploration and analysis of PDB files.

Science.gov (United States)

Mani, Udayakumar; Ravisankar, Sadhana; Ramakrishnan, Sai Mukund

2013-12-01

Protein Data Bank (PDB) is a freely accessible archive of the 3-D structural data of biological molecules. Structure based studies offers a unique vantage point in inferring the properties of a protein molecule from structural data. This is too big a task to be done manually. Moreover, there is no single tool, software or server that comprehensively analyses all structure-based properties. The objective of the present work is to develop an offline computational toolkit, PDB@ containing in-built algorithms that help categorizing the structural properties of a protein molecule. The user has the facility to view and edit the PDB file to his need. Some features of the present work are unique in itself and others are an improvement over existing tools. Also, the representation of protein properties in both graphical and textual formats helps in predicting all the necessary details of a protein molecule on a single platform.
Investigation of the phase formation and dielectric properties of Bi{sub 7}Ta{sub 3}O{sub 18}

Energy Technology Data Exchange (ETDEWEB)

Chon, M.P. [Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Tan, K.B., E-mail: tankb@science.upm.my [Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Khaw, C.C. [Department of Mechanical and Material Engineering, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, 53300 Setapak, Kuala Lumpur (Malaysia); Zainal, Z.; Taufiq Yap, Y.H. [Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Chen, S.K. [Department of Physics, Faculty of Science, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Tan, P.Y. [Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia)

2014-03-25

Highlights: • Synthesis condition of Bi{sub 7}TaO{sub 3}O{sub 18} had been determined. • Recombination of intermediate BiTaO{sub 4} and Bi{sub 3}TaO{sub 7} phases are required for the Bi{sub 7}TaO{sub 3}O{sub 18} phase formation. • Stable material as confirmed by thermal and structural analyses. • Typical ferroelectric showing high dielectric constants and low losses. • Resonance and thermal activated polarisation processes are responsible for the excellent dielectric characteristic. -- Abstract: Polycrystalline Bi{sub 7}Ta{sub 3}O{sub 18} was synthesised at the firing temperature of 950 °C over 18 h via conventional solid state method. It crystallised in a monoclinic system with space group C2/m, Z = 4 similar to that reported diffraction pattern in the Inorganic Crystal Structure Database (ICSD), 1-89-6647. The refined lattice parameters were a = 34.060 (3) Å, b = 7.618 (9) Å, c = 6.647 (6) Å with α = γ = 90° and β = 109.210 (7), respectively. The intermediate phase was predominantly in high-symmetry cubic structure below 800 °C and finally evolved into a low-symmetry monoclinic structured, Bi{sub 7}Ta{sub 3}O{sub 18} at 950 °C. The sample contained grains of various shapes with different orientations in the size ranging from 0.33–22.70 μm. The elemental analysis showed the sample had correct stoichiometry with negligible Bi{sub 2}O{sub 3} loss. Bi{sub 7}Ta{sub 3}O{sub 18} was thermally stable and it exhibited a relatively high relative permittivity, 241 and low dielectric loss, 0.004 at room temperature, ∼30 °C and frequency of 1 MHz.
Biogeochemical cycling of arsenic in coastal salinized aquifers: Evidence from sulfur isotope study

Energy Technology Data Exchange (ETDEWEB)

Kao, Yu-Hsuan [Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei 106, Taiwan, ROC (China); Wang, Sheng-Wei [Agricultural Engineering Research Center, Chungli 320, Taiwan, ROC (China); Liu, Chen-Wuing, E-mail: lcw@gwater.agec.ntu.edu.tw [Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei 106, Taiwan, ROC (China); Wang, Pei-Ling [Institute of Oceanography, National Taiwan University, Taipei 106, Taiwan, ROC (China); Wang, Chung-Ho [Institute of Earth Sciences, Academia Sinica, Taipei 115, Taiwan, ROC (China); Maji, Sanjoy Kumar [Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei 106, Taiwan, ROC (China)

2011-10-15

Arsenic (As) contamination of groundwater, accompanied by critical salinization, occurs in the southwestern coastal area of Taiwan. Statistical analyses and geochemical calculations indicate that a possible source of aqueous arsenic is the reductive dissolution of As-bearing iron oxyhydroxides. There are few reports of the influence of sulfate-sulfide redox cycling on arsenic mobility in brackish groundwater. We evaluated the contribution of sulfate reduction and sulfide re-oxidation on As enrichment using {delta}{sup 34}S{sub [SO{sub 4]}} and {delta}{sup 18}O{sub [SO{sub 4]}} sulfur isotopic analyses of groundwater. Fifty-three groundwater samples were divided into groups of high-As content and salinized (Type A), low-As and non-salinized (Type B), and high-As and non-salinized (Type C) groundwaters, based on hydro-geochemical analysis. The relatively high enrichment of {sup 34}S{sub [SO{sub 4]}} and {sup 18}O{sub [SO{sub 4]}} present in Type A, caused by microbial-mediated reduction of sulfate, and high {sup 18}O enrichment factor ({epsilon}{sub [SO{sub 4-H{sub 2O]}}}), suggests that sulfur disproportionation is an important process during the reductive dissolution of As-containing iron oxyhydroxides. Limited co-precipitation of ion-sulfide increased the rate of As liberation under anaerobic conditions. In contrast to this, Type B and Type C groundwater samples showed high {delta}{sup 18}O{sub [SO{sub 4]}} and low {delta}{sup 34}S{sub [SO{sub 4]}} values under mildly reducing conditions. Base on {sup 18}O mass balance calculations, the oxide sources of sulfate are from infiltrated atmospheric O{sub 2}, caused by additional recharge of dissolved oxygen and sulfide re-oxidation. The anthropogenic influence of extensive pumping also promotes atmospheric oxygen entry into aquifers, altering redox conditions, and increasing the rate of As release into groundwater. - Highlights: {yields} Seawater intrusion and elevated As are the main issues of groundwater in Taiwan
The adsorption of Tl(I), Au(III), Cu(II) and the separation of 199Tl from alpha bombardment of gold target with PDB-18C6

International Nuclear Information System (INIS)

Zhou Dehai; Zhou Jimeng

1989-01-01

The adsorptive behavior of polymer of methyl aldehyde of dibenzo-18-crown-6 (PDB-18C6) in hydrochloric acid medium is studied and it is shown that the adsorption of T1(I), Au(III), and Cu(II) depends on the particle size of the crown ether resins, hydrochloric acid concentration and amount of the crown ether resins used. The difference in the adsorption behavior of different particle sizes of crown ether resins may be used for separating Tl(I), Au(III), and Cu(II) ions. The best eluant of Tl(I) and Au(III) is 0.4 mol/l perchloric acid and 2-ethoxy-ethanol. The recovery for Tl(I) is 82-98.8%. The gold target is bombarded in a 1.2 m cyclotron with 25-27 MeV α-particle with a cumulative beam intensities of 27μA·h, and 199 Tl is separated from the gold target with PDB-18C6. γ-spectrometry has shown that the Tl obtained is 199 Tl of high purity containing only about 0.50% 200 Tl
Three New Offset {delta}{sup 11}B Isotope Reference Materials for Environmental Boron Isotope Studies

Energy Technology Data Exchange (ETDEWEB)

Rosner, M. [BAM Federal Institute for Materials Research and Testing, Berlin (Germany); IsoAnalysis UG, Berlin (Germany); Vogl, J. [BAM Federal Institute for Materials Research and Testing, Berlin (Germany)

2013-07-15

The isotopic composition of boron is a well established tool in various areas of science and industry. Boron isotope compositions are typically reported as {delta}{sup 11}B values which indicate the isotopic difference of a sample relative to the isotope reference material NIST SRM 951. A significant drawback of all of the available boron isotope reference materials is that none of them covers a natural boron isotope composition apart from NIST SRM 951. To fill this gap of required {delta}{sup 11}B reference materials three new solution boric acid reference materials were produced, which cover 60 per mille of the natural boron isotope variation (-20 to 40 per mille {delta}{sup 11}B) of about 100 per mille . The new reference materials are certified for their {delta}{sup 11}B values and are commercially available through European Reference Materials (http://www.erm-crm.org). The newly produced and certified boron isotope reference materials will allow straightforward method validation and quality control of boron isotope data. (author)
A study of the process of joint formation of methane gas-hydrate and authigenic carbonates in bottom sediments in the Sea of Okhotsk

Energy Technology Data Exchange (ETDEWEB)

Esikov, A D [AN SSSR, Moscow (USSR). Water Problems Inst.; Pashkina, V I [AN SSSR, Moscow (USSR). Inst. Okeanologii

1990-01-01

The discovery of gas-hydrates in bottom sediments in the Sea of Okhotsk has allowed isotope fractionation of oxygen and hydrogen to be determined in the formation of the crystal lattice. It was established that the structure of gas-hydrate selectively included the heavier isotopes of oxygen and hydrogen, so that the gas-hydrate water had values of {delta}{sup 18}O = +1.9 per mille and {delta}D = +23 per mille, whereas the interstitial water was ''lighter'' in isotopes, with the values of {delta}{sup 18}O = -0.5 per mille and {delta}D = -5 per mille (relative to SMOW (standard mean ocean water)). The formation of gas-hydrates under the conditions of underwater discharge of methane alters the chemical composition of interstitial water, so that the carbonate equilibrium is shifted, and carbonates of authigenic origin are formed. The isotope composition of the carbonates is characterized by a low content of {sup 13}C({delta}{sup 13}C from -39.3 to -51.8 per mille PDB) and a high content of {sup 18}O({delta}{sup 18}O from + 2.7 to +6.3 per mille PDB) in comparison with carbonates of sea origin. These characteristics of the isotope composition suggest the participation of methane in the formation of authigenic carbonates, due to its anaerobic oxidation and the involvement of sulfate in the silt water. (author).
Growth Rates, Stable Oxygen Isotopes (18O), and Strontium (Sr/Ca) Composition in Two Species of Pacific Sclerosponges (Acanthocheatetes wellsi and Astrosclera willeyana) with 18O Calibration and Application to Paleoceanography

Energy Technology Data Exchange (ETDEWEB)

Grottoli, A.; Adkins, J; Panero, W; Reaman, D; Moots, K

2010-01-01

The isotopic and elemental composition of sclerosponge skeletons is used to reconstruct paleoceanographic records. Yet few studies have systematically examined the natural variability in sclerosponge skeletal {delta}{sup 18}O, growth, and Sr/Ca, and how that may influence the interpretation of sclerosponge proxy records. Here, we analyzed short records in seven specimens of Acanthocheatetes wellsi (high-Mg calcite, 21 mol% Mg) from Palau, four A. wellsi (high-Mg calcite, 21 mol% Mg) from Saipan, and three Astrosclera willeyana (aragonite) sclerosponges from Saipan, as well as one long record in an A. wellsi specimen from Palau spanning 1945-2001.5. In Saipan, species-specific and mineralogical effects appear to have a negligible effect on sclerosponge {delta}{sup 18}O, facilitating the direct comparison of {delta}{sup 18}O records between species at a given location. At both sites, A. wellsi {delta}{sup 18}O and growth rates were sensitive to environmental conditions, but Sr/Ca was not sensitive to the same conditions. High-resolution {delta}{sup 18}O analyses confirmed this finding as both A. wellsi and A. willeyana deposited their skeleton in accordance with the trends in isotopic equilibrium with seawater, though with a 0.27{per_thousand} offset in the case of A. willeyana. In the high-Mg-calcite species A. wellsi, Mg may be interfering with Sr incorporation into the skeleton. On multidecadal timescales, A. wellsi sclerosponge {delta}{sup 18}O in Palau tracked the Southern Oscillation Index variability post-1977, but not pre-1977, coincident with the switch in the Pacific Decadal Oscillation (PDO) at {approx}1976. This suggests that water mass circulation in the region is influenced by El Nino-Southern Oscillation variability during positive PDO phases, but not during negative ones.
Facile hydrothermal synthesis of ultrasmall W{sub 18}O{sub 49} nanoparticles and studies of their photocatalytic activity towards degradation of methylene blue

Energy Technology Data Exchange (ETDEWEB)

Bhuyan, Bishal; Paul, Bappi [Department of Chemistry, National Institute of Technology, Silchar, Silchar, 788010, Assam (India); Dhar, Siddhartha Sankar, E-mail: ssd_iitg@hotmail.com [Department of Chemistry, National Institute of Technology, Silchar, Silchar, 788010, Assam (India); Vadivel, Sethumathavan [Department of Chemistry, PSG College of Technology, Coimbatore, Tamilnadu, 641004 (India)

2017-02-15

Uniformly dispersed ultrasmall tungsten oxide nanoparticles (W{sub 18}O{sub 49}) of sizes around 5–7 nm were synthesized using tungsten hexachloride as tungsten precursor and octadecylamine (ODA) as surfactant and as well as reducing agent. The as-synthesized nanoparticles (NPs) were characterized thoroughly by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) and N{sub 2} adsorption desorption isotherm (BET). From the XRD patterns, formation of monoclinic primitive phase of W{sub 18}O{sub 49} was observed while TEM images showed well dispersed particles of sizes 5–7 nm. The surface area of the W{sub 18}O{sub 49} NPs was found to be 27.17 m{sup 2} g{sup −1}. These ultrasmall W{sub 18}O{sub 49} NPs have been studied as photocatalysts for the first time in the degradation of methylene blue (MB). The photocatalytic activity was evaluated in oxidative degradation of MB with H{sub 2}O{sub 2} under solar irradiation. The particles exhibited pronounced activity in degradation of MB as well as efficient recyclability. The small band gap energy of W{sub 18}O{sub 49} NPs and their large surface area helps in the production of higher electron (e{sup −}) and hole (h{sup +}) pairs which in a way also prevents the e{sup −} and h{sup +} pairs from recombination within the nanoparticles. This greatly improves and enhances the photocatalytic activity of our synthesized nanoparticles. - Highlights: • Ultrasmall W{sub 18}O{sub 49} NPs were synthesized by a facile hydrothermal route. • Octadecylamine was used as both capping and reducing agent. • The XRD patterns revealed formation of monoclinic primitive phase of W{sub 18}O{sub 49}. • The TEM images showed that the material were well dispersed with sizes from 5 to 7 nm. • The synthesized NPs exhibited pronounced photocatalytic activity towards MB degradation.
Decreasing Asian summer monsoon intensity after 1860 AD in the global warming epoch

Energy Technology Data Exchange (ETDEWEB)

Xu, Hai [Institute of Earth Environment, Chinese Academy of Sciences, State Key Laboratory of Loess and Quaternary Geology, Xi' an, Shaanxi Province (China); Hong, Yetang; Hong, Bin [Institute of Geochemistry, Chinese Academy of Sciences, State Key Laboratory of Environmental Geochemistry, Guiyang (China)

2012-10-15

The trend of the Indian summer monsoon (ISM) intensity and its nature during the past 100 and 200 years still remain unclear. In this study we reconstructed the ISM intensity during the past 270 years from tree ring {delta}{sup 18}O at Hongyuan, eastern edge of the Tibet Plateau. The monsoon failures inferred from {delta}{sup 18}O{sub tree} {sub ring} correlate well with those recorded in ice cores, speleothem, and historical literature sources. 22.6, 59.0, and 110.9-years frequency components in the Hongyuan {delta}{sup 18}O{sub tree} {sub ring} series, which may be the responses to solar activities, synchronize well with those recorded in other ISM indices. A notable feature of the reconstructed ISM intensity is the gradually decreasing trend from about 1860 to the present, which is inversely related to the increasing temperature trend contemporaneously. Such ''decreasing ISM intensity-increasing temperature'' tendency can also be supported by ice core records and meteorological records over a wide geographic extension. The decrease in sea surface temperature gradient between tropical and north Indian Ocean, and the decrease in land-sea thermal contrast between tropical Indian Ocean and ''Indian sub-continent-western Himalaya'' are possibly responsible for the observed decreasing ISM trend. (orig.)
Protein Data Bank (PDB): The Single Global Macromolecular Structure Archive.

Science.gov (United States)

Burley, Stephen K; Berman, Helen M; Kleywegt, Gerard J; Markley, John L; Nakamura, Haruki; Velankar, Sameer

2017-01-01

The Protein Data Bank (PDB)--the single global repository of experimentally determined 3D structures of biological macromolecules and their complexes--was established in 1971, becoming the first open-access digital resource in the biological sciences. The PDB archive currently houses ~130,000 entries (May 2017). It is managed by the Worldwide Protein Data Bank organization (wwPDB; wwpdb.org), which includes the RCSB Protein Data Bank (RCSB PDB; rcsb.org), the Protein Data Bank Japan (PDBj; pdbj.org), the Protein Data Bank in Europe (PDBe; pdbe.org), and BioMagResBank (BMRB; www.bmrb.wisc.edu). The four wwPDB partners operate a unified global software system that enforces community-agreed data standards and supports data Deposition, Biocuration, and Validation of ~11,000 new PDB entries annually (deposit.wwpdb.org). The RCSB PDB currently acts as the archive keeper, ensuring disaster recovery of PDB data and coordinating weekly updates. wwPDB partners disseminate the same archival data from multiple FTP sites, while operating complementary websites that provide their own views of PDB data with selected value-added information and links to related data resources. At present, the PDB archives experimental data, associated metadata, and 3D-atomic level structural models derived from three well-established methods: crystallography, nuclear magnetic resonance spectroscopy (NMR), and electron microscopy (3DEM). wwPDB partners are working closely with experts in related experimental areas (small-angle scattering, chemical cross-linking/mass spectrometry, Forster energy resonance transfer or FRET, etc.) to establish a federation of data resources that will support sustainable archiving and validation of 3D structural models and experimental data derived from integrative or hybrid methods.
Natural Tracers and Isotope Techniques to Define Groundwater Recharge and Salinization in the Bou Areg Coastal Aquifer (North Morocco)

Energy Technology Data Exchange (ETDEWEB)

Re, V. [Department of Molecular Sciences and Nanosystems, University Ca' Foscari, Venice (Italy); Allais, E. [ISO4 s.n.c., Torino (Italy); El Hamouti, N. [Multidisciplinary Faculty of Nador, University of Oujda, Nador (Morocco); Bouchnan, R. [Laboratory of Physical Phenomena and Natural Risk Modelling, University of Tangier, Tangier (Morocco); Sacchi, E. [Department of Earth Sciences, University of Pavia, Pavia (Italy); Rizzo, F. [UNESCO International Hydrological Programme, Paris (France); Zuppi, G. M. [Department of Molecular Sciences and Nanosystems, University Ca' Foscari, Venice and Institute of Environmental Geology and Geoengineering, National Research Council, Monterotondo (Italy)

2013-07-15

The geochemical and isotopic ({delta}{sup 2}H, {delta}{sup 18}O, {delta}{sup 13}C, {delta}{sup 15}N{sub NO3},{delta} {sup 18}O{sub NO3}) characterization of the Bou Areg aquifer (North Morocco) based on samples collected during two surveys in November 2009 and June 2010 allowed the identification of run-off from the mountain regions and agricultural return flows as the main sources of aquifer recharge. The high salinization of the aquifer is not only due to the intensive agricultural activities but it is also associated with the natural quality of the catchment. The isotopic signal of dissolved nitrates allowed for the identification of two main sources of nitrogen in the system: (i) fertilizers and (ii) manure and septic effluents. The study, framed within the UNESCO-IHP sub component of the Strategic Partnership for the Mediterranean Large Marine Ecosystem, represents the first isotopic investigation of the area and will serve as a basis for the promotion of robust science based management practices in the region. (author)
Seasonal mercury concentrations and {delta}{sup 15}N and {delta}{sup 13}C values of benthic macroinvertebrates and sediments from a historically polluted estuary in south central Chile

Energy Technology Data Exchange (ETDEWEB)

Diaz-Jaramillo, Mauricio, E-mail: mdiazjaramillo@conicet.gov.ar [Aquatic Systems Research Unit, EULA Chile Environmental Sciences Centre, Universidad de Concepcion (Chile); Munoz, Claudia; Rudolph, Ignacio [Aquatic Systems Research Unit, EULA Chile Environmental Sciences Centre, Universidad de Concepcion (Chile); Servos, Mark [Department of Biology, University of Waterloo, ON (Canada); Barra, Ricardo [Aquatic Systems Research Unit, EULA Chile Environmental Sciences Centre, Universidad de Concepcion (Chile)

2013-01-01

The Lenga Estuary is one of the most industrialized sites in south central Chile where the historic operation of chlor-alkali plants resulted in large quantities of mercury (Hg) being deposited into the estuary. This historical contamination may still represent a risk to the biota in the estuary. To investigate this four macroinvertebrates, Neotrypaea uncinata (ghostshrimp), Elminius kingii (barnacle), Hemigrapsus crenulatus (shore crab) and Perinereis gualpensis (ragworm) were collected seasonally from three different sites in the Lenga Estuary and one in a reference estuary (Tubul Estuary), and analyzed for Hg and stable isotopes ({delta}{sup 15}N and {delta}{sup 13}C). Mercury concentrations in Lenga sediments ranged from 0.4 {+-} 0.1 to 13 {+-} 3 mg/kg, while those in Tubul sediments ranged from 0.02 {+-} 0.01 to 0.07 {+-} 0.09 mg/kg. Total Hg concentrations of invertebrates were significantly different between estuaries (p < 0.05), but not by species or season for each estuary (p > 0.05). In contrast, organic Hg concentrations were different by species and season with shore crab muscle tissues exhibiting the greatest percent difference. Site-specific relationships demonstrated that total Hg concentrations in ragworm best reflected the total Hg sediment mercury concentrations. Signatures of {delta}{sup 13}C were correlated to the organic Hg % rather than total Hg. This suggests that organic Hg concentrations in these species were related to the carbon sources. -- Highlights: Black-Right-Pointing-Pointer Hg in sediments and biota from Lenga Estuary were elevated compared to nearby estuary. Black-Right-Pointing-Pointer Invertebrates showed interspecific and seasonal differences in terms of organic Hg %. Black-Right-Pointing-Pointer Total Hg levels in the ragworm best reflect Hg sediment gradient in Lenga Estuary. Black-Right-Pointing-Pointer Interspecific variation in {delta}{sup 13}C signatures indicated different feeding modes. Black
Representation of viruses in the remediated PDB archive

International Nuclear Information System (INIS)

Lawson, Catherine L.; Dutta, Shuchismita; Westbrook, John D.; Henrick, Kim; Berman, Helen M.

2008-01-01

A new data model for PDB entries of viruses and other biological assemblies with regular noncrystallographic symmetry is described. A new scheme has been devised to represent viruses and other biological assemblies with regular noncrystallographic symmetry in the Protein Data Bank (PDB). The scheme describes existing and anticipated PDB entries of this type using generalized descriptions of deposited and experimental coordinate frames, symmetry and frame transformations. A simplified notation has been adopted to express the symmetry generation of assemblies from deposited coordinates and matrix operations describing the required point, helical or crystallographic symmetry. Complete correct information for building full assemblies, subassemblies and crystal asymmetric units of all virus entries is now available in the remediated PDB archive
Protein Data Bank (PDB)

Data.gov (United States)

U.S. Department of Health & Human Services — The Protein Data Bank (PDB) archive is the single worldwide repository of information about the 3D structures of large biological molecules, including proteins and...
PDBsum: Structural summaries of PDB entries

OpenAIRE

Laskowski, Roman A.; Jabłońska, Jagoda; Pravda, Lukáš; Vařeková, Radka Svobodová; Thornton, Janet M.

2017-01-01

Abstract PDBsum is a web server providing structural information on the entries in the Protein Data Bank (PDB). The analyses are primarily image‐based and include protein secondary structure, protein‐ligand and protein‐DNA interactions, PROCHECK analyses of structural quality, and many others. The 3D structures can be viewed interactively in RasMol, PyMOL, and a JavaScript viewer called 3Dmol.js. Users can upload their own PDB files and obtain a set of password‐protected PDBsum analyses for e...
The PDB_REDO server for macromolecular structure model optimization

Directory of Open Access Journals (Sweden)

Robbie P. Joosten

2014-07-01

Full Text Available The refinement and validation of a crystallographic structure model is the last step before the coordinates and the associated data are submitted to the Protein Data Bank (PDB. The success of the refinement procedure is typically assessed by validating the models against geometrical criteria and the diffraction data, and is an important step in ensuring the quality of the PDB public archive [Read et al. (2011, Structure, 19, 1395–1412]. The PDB_REDO procedure aims for `constructive validation', aspiring to consistent and optimal refinement parameterization and pro-active model rebuilding, not only correcting errors but striving for optimal interpretation of the electron density. A web server for PDB_REDO has been implemented, allowing thorough, consistent and fully automated optimization of the refinement procedure in REFMAC and partial model rebuilding. The goal of the web server is to help practicing crystallographers to improve their model prior to submission to the PDB. For this, additional steps were implemented in the PDB_REDO pipeline, both in the refinement procedure, e.g. testing of resolution limits and k-fold cross-validation for small test sets, and as new validation criteria, e.g. the density-fit metrics implemented in EDSTATS and ligand validation as implemented in YASARA. Innovative ways to present the refinement and validation results to the user are also described, which together with auto-generated Coot scripts can guide users to subsequent model inspection and improvement. It is demonstrated that using the server can lead to substantial improvement of structure models before they are submitted to the PDB.

Investigation of luminescence mechanism in La{sub 0.2}Y{sub 1.8}O{sub 3} scintillator

Energy Technology Data Exchange (ETDEWEB)

Sahi, Sunil [Department of Physics, The University of Texas at Arlington, Arlington, TX 76019-0059 (United States); Wang, Zhiqiang [Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7 (Canada); Luo, Junming [School of Materials Science and Engineering, Nanchang Hangkong University, Nanchang 330063 (China); Groza, Michael [Department of Life and Physical Sciences, Fisk University, Nashville, TN 37208-3051 (United States); Li, Jiang [Key Laboratory of Transparent Opto-functional Inorganic Materials, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Zhang, Junying [Department of Physics, Beihang University, Beijing 100191 (China); Chen, Wei, E-mail: weichen@uta.edu [Department of Physics, The University of Texas at Arlington, Arlington, TX 76019-0059 (United States); Pan, Yubai [Key Laboratory of Transparent Opto-functional Inorganic Materials, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Burger, Arnold [Department of Life and Physical Sciences, Fisk University, Nashville, TN 37208-3051 (United States); Sham, Tsun-Kong [Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7 (Canada)

2016-05-15

La{sub 0.2}Y{sub 1.8}O{sub 3} is a new and promising scintillator which is based on the host material without doping. Here the time gated X-ray excited optical luminescence is measured by using the excitation energy below, above and at the La L{sub 3}-edge. A relatively slow and broad emission with peak at 415 nm has been observed as the dominant emission. Also, a weak emission at 360 nm is observed at the fast window, associated with the recombination of trapped excitons in Y{sub 2}O{sub 3} host. The observations show that the broad emission at 415 nm is most likely due to the recombination of trapped excitons associated with the La{sup 3+} doping into Y{sub 2}O{sub 3} sites.
BLOCKS - PDB ATOM matching - DB-SPIRE | LSDB Archive [Life Science Database Archive metadata

Lifescience Database Archive (English)

Full Text Available List Contact us DB-SPIRE BLOCKS - PDB ATOM matching Data detail Data name BLOCKS - PDB ATOM matching DOI 10....18908/lsdba.nbdc00411-008 Description of data contents Sequence numbers of PDB entries/chains whose ATOM mat...ches a BLOCKS entry Data file File name: dbspire_blocks_pdb_atom.zip File URL: ftp://ftp.biosciencedbc.jp/ar...chive/dbspire/LATEST/dbspire_blocks_pdb_atom.zip File size: 6.2 MB Simple search ...URL http://togodb.biosciencedbc.jp/togodb/view/dbspire_blocks_pdb_atom#en Data acquisition method BLOCKS, PD
Room-temperature multiferroic and magnetocapacitance effects in M-type hexaferrite BaFe{sub 10.2}Sc{sub 1.8}O{sub 19}

Energy Technology Data Exchange (ETDEWEB)

Tang, Rujun, E-mail: tangrj@suda.edu.cn, E-mail: yanghao@nuaa.edu.cn; Zhou, Hao; You, Wenlong [Jiangsu Key Laboratory of Thin Films, College of Physics, Optoelectronics and Energy, Soochow University, Suzhou 215006 (China); Yang, Hao, E-mail: tangrj@suda.edu.cn, E-mail: yanghao@nuaa.edu.cn [College of Science, Nanjing University of Aeronautics and Astronautics, Nanjing 211106 (China)

2016-08-22

The room-temperature multiferroic and magnetocapacitance (MC) effects of polycrystalline M-type hexaferrite BaFe{sub 10.2}Sc{sub 1.8}O{sub 19} have been investigated. The results show that the magnetic moments of insulating BaFe{sub 10.2}Sc{sub 1.8}O{sub 19} can be manipulated by the electric field at room temperature, indicating the existence of magnetoelectric coupling. Moreover, large MC effects are also observed around the room temperature. A frequency dependence analysis shows that the Maxwell-Wagner type magnetoresistance effect is the dominant mechanism for MC effects at low frequencies. Both the magnetoelectric-type and non-magnetoelectric-type spin-phonon couplings contribute to the MC effects at high frequencies with the former being the dominant mechanism. The above results show that the hexaferrite BaFe{sub 10.2}Sc{sub 1.8}O{sub 19} is a room-temperature multiferroic material that can be potentially used in magnetoelectric devices.
C{sub 4} plant isotopic composition ({delta}{sup 13}C) evidence for urban CO{sub 2} pollution in the city of Cotonou, Benin (West Africa)

Energy Technology Data Exchange (ETDEWEB)

Kelome, Nelly C.; Leveque, Jean; Andreux, Francis; Milloux, Marie-Jeanne [UMR Microbiologie et Geochimie des Sols INRA, Universite de Bourgogne, Centre des Sciences de la Terre, 6 Bd Gabriel, 21000 Dijon (France); Oyede, Lucien-Marc [Departement des Sciences de la Terre, Universite d' Abomey-Calavi, 01 B.P. 526, Cotonou (Benin)

2006-08-01

The carbon isotopic composition ({delta}{sup 13}C) of plants can reveal the isotopic carbon content of the atmosphere in which they develop. The {delta}{sup 13}C values of air and plants depend on the amount of atmospheric fossil fuel CO{sub 2}, which is chiefly emitted in urban areas. A new indicator of CO{sub 2} pollution is tested using the {delta}{sup 13}C variation in a C{sub 4} grass: Eleusine indica. A range of about 4%% delta units was observed at different sites in Cotonou, the largest city in the Republic of Benin. The highest {delta}{sup 13}C values, from -12%% to -14%%, were found in low traffic zones; low {delta}{sup 13}C values, from -14%% to -16%%, were found in high traffic zones. The amount of fossil fuel carbon assimilated by plants represented about 20% of the total plant carbon content. An overall decrease in plant {delta}{sup 13}C values was observed over a four-year monitoring period. This decrease was correlated with increasing vehicle traffic. The {delta}{sup 13}C dataset and the corresponding geographical database were used to map and define zones of high and low {sup 13}C-depleted CO{sub 2} emissions in urban and sub-urban areas. The spatial distribution follows dominant wind directions, with the lowest emission zones found in the southwest of Cotonou. High CO{sub 2} emissions occurred in the north, the east and the center, providing evidence of intense anthropogenic activity related to industry and transportation. (author)
C{sub 4} plant isotopic composition ((delta){sup 13}C) evidence for urban CO{sub 2} pollution in the city of Cotonou, Benin (West Africa)

Energy Technology Data Exchange (ETDEWEB)

Kelome, Nelly C.; Leveque, Jean; Andreux, Francis; Milloux, Marie-Jeanne [UMR Microbiologie et Geochimie des Sols INRA, Universite de Bourgogne, Centre des Sciences de la Terre, 6 Bd Gabriel, 21000 Dijon (France); Oyede, Lucien-Marc [Departement des Sciences de la Terre, Universite d' Abomey-Calavi, 01 B.P. 526, Cotonou (Benin)

2006-08-01

The carbon isotopic composition ((delta){sup 13}C) of plants can reveal the isotopic carbon content of the atmosphere in which they develop. The (delta){sup 13}C values of air and plants depend on the amount of atmospheric fossil fuel CO{sub 2}, which is chiefly emitted in urban areas. A new indicator of CO{sub 2} pollution is tested using the (delta){sup 13}C variation in a C{sub 4} grass: Eleusine indica. A range of about 4%% delta units was observed at different sites in Cotonou, the largest city in the Republic of Benin. The highest (delta){sup 13}C values, from -12%% to -14%%, were found in low traffic zones; low (delta){sup 13}C values, from -14%% to -16%%, were found in high traffic zones. The amount of fossil fuel carbon assimilated by plants represented about 20% of the total plant carbon content. An overall decrease in plant (delta){sup 13}C values was observed over a four-year monitoring period. This decrease was correlated with increasing vehicle traffic. The (delta){sup 13}C dataset and the corresponding geographical database were used to map and define zones of high and low {sup 13}C-depleted CO{sub 2} emissions in urban and sub-urban areas. The spatial distribution follows dominant wind directions, with the lowest emission zones found in the southwest of Cotonou. High CO{sub 2} emissions occurred in the north, the east and the center, providing evidence of intense anthropogenic activity related to industry and transportation. (author)
PDBsum: Structural summaries of PDB entries.

Science.gov (United States)

Laskowski, Roman A; Jabłońska, Jagoda; Pravda, Lukáš; Vařeková, Radka Svobodová; Thornton, Janet M

2018-01-01

PDBsum is a web server providing structural information on the entries in the Protein Data Bank (PDB). The analyses are primarily image-based and include protein secondary structure, protein-ligand and protein-DNA interactions, PROCHECK analyses of structural quality, and many others. The 3D structures can be viewed interactively in RasMol, PyMOL, and a JavaScript viewer called 3Dmol.js. Users can upload their own PDB files and obtain a set of password-protected PDBsum analyses for each. The server is freely accessible to all at: http://www.ebi.ac.uk/pdbsum. © 2017 The Protein Society.
High temperature corrosion kinetics study of IN-657 and HK-40 superalloys in contact with an 82% K[sub 2]S[sub 2]O[sub 7]-18% V[sub 2]O[sub 5] eutectic melt. Estudio de la cinetica de corrosion a alta temperatura de las superaleaciones IN-657 y HK-40 en presencia de la mezcla eutectica fundida 82% K[sub 2]S[sub 2]O[sub 7]-18% V[sub 2]O[sub 5

Energy Technology Data Exchange (ETDEWEB)

Pardo, A.; Otero, E.; Perez, F.J.; Alvarez, J.F.; Utrilla, M. V. (Universidad Complutense de Madrid (Spain). Facultad de Ciencias Quimicas)

1993-01-01

Electrochemical methods are used to study the corrosion kinetics of the IN-657 and HK-40 super-alloys in contact with the eutectic melt 82% K[sub 2]S[sub 2]O[sub 7]-18% V[sub 2]O[sub 5] with different carbon contents and at different temperatures (773 and 823 K). The results obtained are discussed in relation with the chemistry of the process. The kinetics equations of the corrosion process are given to the two super-alloys studied and at different test conditions. (Author) 18 refs.
ccPDB: compilation and creation of data sets from Protein Data Bank.

Science.gov (United States)

Singh, Harinder; Chauhan, Jagat Singh; Gromiha, M Michael; Raghava, Gajendra P S

2012-01-01

ccPDB (http://crdd.osdd.net/raghava/ccpdb/) is a database of data sets compiled from the literature and Protein Data Bank (PDB). First, we collected and compiled data sets from the literature used for developing bioinformatics methods to annotate the structure and function of proteins. Second, data sets were derived from the latest release of PDB using standard protocols. Third, we developed a powerful module for creating a wide range of customized data sets from the current release of PDB. This is a flexible module that allows users to create data sets using a simple six step procedure. In addition, a number of web services have been integrated in ccPDB, which include submission of jobs on PDB-based servers, annotation of protein structures and generation of patterns. This database maintains >30 types of data sets such as secondary structure, tight-turns, nucleotide interacting residues, metals interacting residues, DNA/RNA binding residues and so on.
PDB-Explorer: a web-based interactive map of the protein data bank in shape space.

Science.gov (United States)

Jin, Xian; Awale, Mahendra; Zasso, Michaël; Kostro, Daniel; Patiny, Luc; Reymond, Jean-Louis

2015-10-23

The RCSB Protein Data Bank (PDB) provides public access to experimentally determined 3D-structures of biological macromolecules (proteins, peptides and nucleic acids). While various tools are available to explore the PDB, options to access the global structural diversity of the entire PDB and to perceive relationships between PDB structures remain very limited. A 136-dimensional atom pair 3D-fingerprint for proteins (3DP) counting categorized atom pairs at increasing through-space distances was designed to represent the molecular shape of PDB-entries. Nearest neighbor searches examples were reported exemplifying the ability of 3DP-similarity to identify closely related biomolecules from small peptides to enzyme and large multiprotein complexes such as virus particles. The principle component analysis was used to obtain the visualization of PDB in 3DP-space. The 3DP property space groups proteins and protein assemblies according to their 3D-shape similarity, yet shows exquisite ability to distinguish between closely related structures. An interactive website called PDB-Explorer is presented featuring a color-coded interactive map of PDB in 3DP-space. Each pixel of the map contains one or more PDB-entries which are directly visualized as ribbon diagrams when the pixel is selected. The PDB-Explorer website allows performing 3DP-nearest neighbor searches of any PDB-entry or of any structure uploaded as protein-type PDB file. All functionalities on the website are implemented in JavaScript in a platform-independent manner and draw data from a server that is updated daily with the latest PDB additions, ensuring complete and up-to-date coverage. The essentially instantaneous 3DP-similarity search with the PDB-Explorer provides results comparable to those of much slower 3D-alignment algorithms, and automatically clusters proteins from the same superfamilies in tight groups. A chemical space classification of PDB based on molecular shape was obtained using a new atom-pair 3
Metabolic origin of the {delta}{sup 13}C of respired CO{sub 2} in roots of Phaseolus vulgaris

Energy Technology Data Exchange (ETDEWEB)

Bathellier, C.; Tcherkez, G.; Cornic, G.; Ghashghaie, J. [Laboratoire d' Ecologie, Systematique et Evolution - ESE, CNRS-UMR 8079 - IFR 87, Batiment 362, Universite Paris-Sud, 91405-Orsay Cedex (France); Tcherkez, G. [Plateforme Metabolisme-Metabolome, IFR87 La Plante et son Environnement, Institut de Biotechnologie des Plantes, Batiment 630, Universite Paris-Sud, 91405-Orsay Cedex (France); Bligny, R.; Gout, E. [Laboratoire de Physiologie Cellulaire Vegetale CEA-Grenoble 17, rue des Martyrs, 38054 Grenoble Cedex 9 (France)

2009-07-01

- Root respiration is a major contributor to soil CO{sub 2} efflux, and thus an important component of ecosystem respiration. But its metabolic origin, in relation to the carbon isotope composition ({delta}{sup 13}C), remains poorly understood. - Here, {sup 13}C analysis was conducted on CO{sub 2} and metabolites under typical conditions or under continuous darkness in French bean (Phaseolus vulgaris) roots. {sup 13}C contents were measured either under natural abundance or following pulse-chase labeling with {sup 13}C-enriched glucose or pyruvate, using isotope ratio mass spectrometer (IRMS) and nuclear magnetic resonance (NMR) techniques. - In contrast to leaves, no relationship was found between the respiratory quotient and the {delta}{sup 13}C of respired CO{sub 2}, which stayed constant at a low value (c. -27.5 per thousand) under continuous darkness. With labeling experiments, it is shown that such a pattern is explained by the {sup 13}C-depleting effect of the pentose phosphate pathway; and the involvement of the Krebs cycle fueled by either the glycolytic input or the lipid/protein recycling. The anaplerotic phosphoenolpyruvate carboxylase (PEPc) activity sustained glutamic acid (Glu) synthesis, with no net effect on respired CO{sub 2}. - These results indicate that the root {delta}{sup 13}C signal does not depend on the availability of root respiratory substrates and it is thus plausible that, unless the {sup 13}C photosynthetic fractionation varies at the leaf level, the root {delta}{sup 13}C signal hardly changes under a range of natural environmental conditions. (authors)
The Use of {delta}{sup 37}CL to Explain Origin and Production of Salt from the Saline Spring 'Fonte da Pipa' in Rio Maior (Central Portugal)

Energy Technology Data Exchange (ETDEWEB)

Eggenkamp, H. G.M.; Marques, J. M. [Centro de Petrologia e Geoquimica, Instituto Superior Tecnico, Lisbon (Portugal); Graca, H. [Centro Hospitalar das Caldas da Rainha, Caldas da Rainha (Portugal)

2013-07-15

Salt extraction in Rio Maior (Central Portugal) is unique in the sense that salt is exploited from a very saline (134 g/L NaCl) terrestrial spring. This spring receives its salt through meteoric water circulation from nearby hills along a shallow salt diapir. This is shown using {delta}{sup 37}Cl, as the composition in dug wells between the mountains and the saline spring is comparable, while {delta}{sup 37}Cl in a well to the east is significantly different. Unlike seawater this spring contains nearly pure NaCl, giving us the opportunity to determine {delta}{sup 37}Cl values in a natural salt precipitating system beyond the point where (in seawater) potassium and magnesium chlorides start to precipitate. {delta}{sup 37}Cl values were determined from brines and by precipitating salt in salt pans with different evaporation stages. Fractionation of up to 1 per mille was found. To complement these natural data, evaporation/precipitation experiments are currently being conducted under controlled laboratory conditions. First results of these experiments indicate that during continued evaporation and precipitation {delta}{sup 37}Cl continues to decrease. (author)
PDBCOP: PDB comparison program

Czech Academy of Sciences Publication Activity Database

Fejfarová, Karla; Dohnálek, Jan; Hašek, Jindřich

2015-01-01

Roč. 22, č. 1 (2015), s. 35 ISSN 1211-5894. [Discussions in Structural Molecular Biology /13./. 19.03.2015-21.03.2015, Nové Hrady] R&D Projects: GA MŠk(CZ) EE2.3.30.0029; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61389013 ; RVO:86652036 Keywords : crystal structure * protein * PDB Subject RIV: CE - Biochemistry
PyPDB: a Python API for the Protein Data Bank.

Science.gov (United States)

Gilpin, William

2016-01-01

We have created a Python programming interface for the RCSB Protein Data Bank (PDB) that allows search and data retrieval for a wide range of result types, including BLAST and sequence motif queries. The API relies on the existing XML-based API and operates by creating custom XML requests from native Python types, allowing extensibility and straightforward modification. The package has the ability to perform many types of advanced search of the PDB that are otherwise only available through the PDB website. PyPDB is implemented exclusively in Python 3 using standard libraries for maximal compatibility. The most up-to-date version, including iPython notebooks containing usage tutorials, is available free-of-charge under an open-source MIT license via GitHub at https://github.com/williamgilpin/pypdb, and the full API reference is at http://williamgilpin.github.io/pypdb_docs/html/. The latest stable release is also available on PyPI. wgilpin@stanford.edu. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.
{Delta}{sup 14}C level of annual plants and fossil fuel derived CO{sub 2} distribution across different regions of China

Energy Technology Data Exchange (ETDEWEB)

Xi, X.T.; Ding, X.F.; Fu, D.P. [State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871 (China); Zhou, L.P. [Laboratory for Earth Surface Processes, Department of Geography, Peking University, Beijing 100871 (China); Liu, K.X., E-mail: kxliu@pku.edu.cn [State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871 (China)

2013-01-15

The {sup 14}C level in annual plants is a sensitive tracer for monitoring fossil fuel derived CO{sub 2} in the atmosphere. Corn leave samples were selected from different regions of China, including high mountains in the Tibetan Plateau, grassland in Inner Mongolia, and inland and coastal cities during the summer of 2010. The {sup 14}C/{sup 12}C ratio of the samples was measured with the NEC compact AMS system at the Institute of Heavy Ion Physics, Peking University. The fossil fuel derived CO{sub 2} was estimated by comparing the measured {Delta}{sup 14}C values of corn leave samples to background atmospheric {Delta}{sup 14}C level. The influences of topography, meteorological conditions and carbon cycling processes on the fossil fuel derived CO{sub 2} concentration are considered when interpreting the data. Our results show a clear association of the low {Delta}{sup 14}C values with regions where human activities are intensive.
Geological setting, isotope studies (C, O and Pb) and associated metals in the Tocantinzinho gold deposit, Tapajos domain, Tapajos-Parima Province; Contexto geologico, estudos isotopicos (C, O e Pb) e associacao metalica do deposito aurifero Tocantinzinho, dominio Tapajos, Provincia Tapajos-Parima

Energy Technology Data Exchange (ETDEWEB)

Villas, Raimundo Netuno Nobre [Universidade Federal do Para (UFPA), Belem, PA (Brazil); Santiago, Erika Suellen Barbosa; Castilho, Marilia Portela, E-mail: netuno@ufpa.br, E-mail: esbsantiago@gmail.com, E-mail: castilho.marilia@hotmail.com [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Inst. de Geociencias. Programa de Pos-graduacao em Geologia e Geoquimica

2013-03-15

The Tocantinzinho ore deposit is located along a NW-SE-trending lineament, southwestern of Itaituba (Para, Brazil), and is the largest known gold deposit of the Tapajos Province. The host Tocantinzinho granite is essentially isotropic and dominated by syenogranites and monzogranites that have been weakly to moderately altered by hydrothermal fluids. Microclinization (earliest), chloritization, sericitization, silicification and carbonatization (latest) are the main types of alteration. Most mineralization was contemporaneous with the sericitization/silicification and is represented by sulfide- and gold-bearing veinlets which locally occur as stockwork. Pyrite, chalcopyrite, sphalerite and galena are the most common sulfides. Among the ore metals, Cu, Pb and Zn present the highest contents, but Mo, As and Bi locally show anomalous concentrations. The relationship of Au with Cu, Pb or Zn is at random and the Au/Ag ratios range from 0.05 to 0.5. The higher the sulfide contents, the higher the Au concentrations, though it occurs mainly included in pyrite. Zircon monocrystals from the Tocantinzinho granite yielded an average Pb-Pb age of 1982 {+-}8Ma and may represent an earlier event of the Creporizao magmatic arc. {delta}{sup 13}C{sub PDB} values for calcite from the carbonatization stage fall dominantly between -3.45 and -2.29 Per-Mille-Sign , being compatible with a deep crustal source that may include carbonatite reservoirs. In turn, {delta}{sup 18}O{sub SMOW} values vary from +5.97 to +14.10 Per-Mille-Sign , being indicative of magmatic derivation, although the less positive values suggest contribution from surficial waters. Unpublished fluid inclusion study reveals the presence of aquo-carbonic fluids, whose CO{sub 2} could have been dissolved in the granitic magma rather than being related to the shear zone. The available data allow the Tocantinzinho deposit to be classified as a granite-hosted, intrusion-related gold deposit. (author)
Flow of river water into a Karstic limestone aquifer. 1. Tracing the young fraction in groundwater mixtures in the Upper Floridan Aquifer near Valdosta, Georgia

Energy Technology Data Exchange (ETDEWEB)

Plummer, L.N.; Busenberg, E. [U.S. Geological Survey, 432 National Center, Reston, VA (United States); McConnell, J.B. [U.S. Geological Survey, 3039 Amwiler Rd., Atlanta, GA (United States); Drenkard, S.; Schlosser, P. [Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY (United States); Michel, R.L. [U.S. Geological Survey, Mail Stop 434, 345 Middlefield Road, Menlo Park, CA (United States)

1998-11-01

he quality of water in the Upper Floridan aquifer near Valdosta, Georgia is affected locally by discharge of Withlacoochee River water through sinkholes in the river bed. Data on transient tracers and other dissolved substances, including Cl{sup -}, {sup 3}H, tritiogenic helium-3 ({sup 3}He), chlorofluorocarbons (CFC-11, CFC-12, CFC-113), organic C (DOC), O{sub 2} (DO), H{sub 2}S, CH{sub 4}, {delta}{sup 18}O, {delta}D, and {sup 14}C were investigated as tracers of Withlacoochee River water in the Upper Floridan aquifer. The concentrations of all tracers were affected by dilution and mixing. Dissolved Cl{sup -}, {delta}{sup 18}O, {delta}D, CFC-12, and the quantity ({sup 3}H+{sup 3}He) are stable in water from the Upper Floridan aquifer, whereas DOC, DO, H{sub 2}S, CH{sub 4}, {sup 14}C, CFC-11, and CFC-113 are affected by microbial degradation and other geochemical processes occurring within the aquifer. Groundwater mixing fractions were determined by using dissolved Cl{sup -} and {delta}{sup 18}O data, recognizing 3 end-member water types in the groundwater mixtures: (1) Withlacoochee River water ({delta}{sup 18}O=-2.5{+-}0.3per thousand, Cl{sup -}=12.2{+-}2 mg/l), (2) regional infiltration water ({delta}{sup 18}O=-4.2{+-}0.1per thousand, Cl{sup -}=2.3{+-}0.1 mg/l), and (3) regional paleowater resident in the Upper Floridan aquifer ({delta}{sup 18}O=-3.4{+-}0.1per thousand, Cl{sup -}=2.6{+-}0.1 mg/l) (uncertainties are {+-}1{sigma}). Error simulation procedures were used to define uncertainties in mixing fractions. Fractions of river water in groundwater range from 0 to 72% and average 10%. The influence of river-water discharge on the quality of water in the Upper Floridan aquifer was traced from the sinkhole area on the Withlacoochee River 25 km SE in the direction of regional groundwater flow. Infiltration of water is most significant to theN and NW of Valdosta, but becomes negligible to the S and SE in the direction of general thickening of post-Eocene confining
Hexagonal perovskites with cationic vacancies. 12. Structure determination on Ba/sub 6/W/sub 4/vacant/sub 2/O/sub 18/

Energy Technology Data Exchange (ETDEWEB)

Kemmler-Sack, S; Treiber, U [Tuebingen Univ. (Germany, F.R.). Lehrstuhl fuer Anorganische Chemie 2

1979-08-01

The stacking polytype Ba/sub 6/W/sub 4/vacant/sub 2/O/sub 18/ is the first oxide variant of the Cs/sub 3/Tl/sub 2/Cl/sub 9/-type. The structure determination gave for the space group R3c with the sequence (h)/sub 6/, Z = 3, the refined, intensity related R' value of 6.8%. The octahedral net consists of groups of two face sharing WO/sub 6/ octahedra (W/sub 2/ Osub(6/2)O/sub 6/), which are in the (110) plane displaced against each other. In the double octahedra the tungsten atoms are shifted away from their ideal central position (W-W:2.32/sub 7/ A) with the result, that the W-W distance has increased to 2.90/sub 5/ A.
LS-SNP/PDB: annotated non-synonymous SNPs mapped to Protein Data Bank structures.

Science.gov (United States)

Ryan, Michael; Diekhans, Mark; Lien, Stephanie; Liu, Yun; Karchin, Rachel

2009-06-01

LS-SNP/PDB is a new WWW resource for genome-wide annotation of human non-synonymous (amino acid changing) SNPs. It serves high-quality protein graphics rendered with UCSF Chimera molecular visualization software. The system is kept up-to-date by an automated, high-throughput build pipeline that systematically maps human nsSNPs onto Protein Data Bank structures and annotates several biologically relevant features. LS-SNP/PDB is available at (http://ls-snp.icm.jhu.edu/ls-snp-pdb) and via links from protein data bank (PDB) biology and chemistry tabs, UCSC Genome Browser Gene Details and SNP Details pages and PharmGKB Gene Variants Downloads/Cross-References pages.
Nano/micro Sr{sub 2}Bi{sub 4}Ti{sub 5}O{sub 18} crystallites: Size dependent structural, second harmonic and piezoelectric properties

Energy Technology Data Exchange (ETDEWEB)

Tukaram, Shet; Bhimireddi, Rajasekhar; Varma, K.B.R., E-mail: kbrvarma@mrc.iisc.ernet.in

2016-09-15

Graphical abstract: Synthesis of Sr{sub 2}Bi{sub 4}Ti{sub 5}O{sub 18} nano/micro crystallites and their size dependent non-linear optical and piezoelectric responses. - Highlights: • Nano/microcrystallites of Sr{sub 2}Bi{sub 4}Ti{sub 5}O{sub 18} were synthesized via sol-gel route. • Crystallite size dependent structural and physical properties were studied. • SHG intensity (1.4 times that of KDP powder) from these crystallites was recorded. • PFM studies on isolated crystallite of 480 nm exhibited d{sub 33} as high as 27 pm/V. • Single domain nature of the crystallites below 160 nm was observed. - Abstract: Strontium bismuth titanate (Sr{sub 2}Bi{sub 4}Ti{sub 5}O{sub 18}) powders comprising crystallites of average sizes in the range of 94–1400 nm were prepared via citrate-assisted sol-gel route. With an increase in the average crystallite size there was a change in the lattice parameters and shift in the Raman vibration modes. Second harmonic signal (532 nm) intensity of the Sr{sub 2}Bi{sub 4}Ti{sub 5}O{sub 18} powders increased with the increase in the average crystallite size and the maximum intensity obtained in the reflection mode was 1.4 times as high as that of the powdered KH{sub 2}PO{sub 4}. Piezo Force Microscopic analyses carried out on isolated crystallite of size 74 nm, established a single domain nature with the coercive field as high as 347 kV/cm. There was a systematic increase in the d{sub 33} value with an increase in the size of the isolated crystallites and a high piezoelectric coefficient of ∼27 pm/V was obtained from an isolated crystallite of size 480 nm.
Macroalgal bioindicators (growth, tissue N, {delta}{sup 15}N) detect nutrient enrichment from shrimp farm effluent entering Opunohu Bay, Moorea, French Polynesia

Energy Technology Data Exchange (ETDEWEB)

Lin, David T. [Department of Zoology, University of Hawaii at Manoa, 2538 McCarthy Mall, Edmondson 152, Honolulu, HI 96822 (United States)], E-mail: david.t.lin@ucla.edu; Fong, Peggy [Department of Ecology and Evolutionary Biology, University of California, Los Angeles, 621 Young Drive South, Los Angeles, CA 90095 (United States)

2008-02-15

Nutrient enrichment from shrimp aquaculture poses an increasing environmental threat due to the industry's projected rapid growth and unsustainable management practices. Traditional methods to monitor impacts emphasize water quality sampling; however, there are many advantages to bioindicators, especially in developing countries. We investigated the usefulness of three bioindicators-growth, tissue nitrogen content and nitrogen stable isotope signature ({delta}{sup 15}N)-in the tropical red macroalga Acanthophora spicifera. Algae were collected, cultured, and deployed in a spatial array around the outflow from a shrimp farm in Moorea, French Polynesia, to detect nitrogenous wastes. All three parameters were highest adjacent to the shrimp farm indicating nutrient enrichment, and {delta}{sup 15}N values confirmed the shrimp farm as the dominant nutrient source (5.63-5.96 per mille ). Isotope ratios proved the most sensitive indicator, as {delta}{sup 15}N signatures were detected at the most distant sites tested, confirming their usefulness in tracing nutrients and mapping the spatial extent of enrichment.

PDB4DNA: Implementation of DNA geometry from the Protein Data Bank (PDB) description for Geant4-DNA Monte-Carlo simulations

Science.gov (United States)

Delage, E.; Pham, Q. T.; Karamitros, M.; Payno, H.; Stepan, V.; Incerti, S.; Maigne, L.; Perrot, Y.

2015-07-01

This paper describes PDB4DNA, a new Geant4 user application, based on an independent, cross-platform, free and open source C++ library, so-called PDBlib, which enables use of atomic level description of DNA molecule in Geant4 Monte Carlo particle transport simulations. For the evaluation of direct damage induced on the DNA molecule by ionizing particles, the application makes use of an algorithm able to determine the closest atom in the DNA molecule to energy depositions. Both the PDB4DNA application and the PDBlib library are available as free and open source under the Geant4 license.
Chemical and isotopic composition of high-temperature gases from the new Andesitic lava dome in the Soufriere of Saint-Vincent (Lesser Antilles)

Energy Technology Data Exchange (ETDEWEB)

Allard, P. (Centre des Faibles radioactivites, Gif-sur-Yvette (France))

1981-11-09

High-temperature gases emitted by the new lava dome built within the crater of the Soufriere of Saint-Vincent, in 1979, were collected. Their chemical composition and a possible deep-seated origin for carbon (mean delta/sup 13/C=-5.5 0/00 vs PDB) are discussed here.
The young person's guide to the PDB.

Science.gov (United States)

Minor, Wladek; Dauter, Zbigniew; Jaskolski, Mariusz

The Protein Data Bank (PDB), created in 1971 when merely seven protein crystal structures were known, today holds over 120, 000 experimentally-determined three-dimensional models of macromolecules, including gigantic structures comprised of hundreds of thousands of atoms, such as ribosomes and viruses. Most of the deposits come from X-ray crystallography experiments, with important contributions also made by NMR spectroscopy and, recently, by the fast growing Cryo-Electron Microscopy. Although the determination of a macromolecular crystal structure is now facilitated by advanced experimental tools and by sophisticated software, it is still a highly complicated research process requiring specialized training, skill, experience and a bit of luck. Understanding the plethora of structural information provided by the PDB requires that its users (consumers) have at least a rudimentary initiation. This is the purpose of this educational overview.
SEQATOMS: a web tool for identifying missing regions in PDB in sequence context

NARCIS (Netherlands)

Brandt, B.W.; Heringa, J.; Leunissen, J.A.M.

2008-01-01

With over 46 000 proteins, the Protein Data Bank (PDB) is the most important database with structural information of biological macromolecules. PDB files contain sequence and coordinate information. Residues present in the sequence can be absent from the coordinate section, which means their
PDB Editor: a user-friendly Java-based Protein Data Bank file editor with a GUI.

Science.gov (United States)

Lee, Jonas; Kim, Sung Hou

2009-04-01

The Protein Data Bank file format is the format most widely used by protein crystallographers and biologists to disseminate and manipulate protein structures. Despite this, there are few user-friendly software packages available to efficiently edit and extract raw information from PDB files. This limitation often leads to many protein crystallographers wasting significant time manually editing PDB files. PDB Editor, written in Java Swing GUI, allows the user to selectively search, select, extract and edit information in parallel. Furthermore, the program is a stand-alone application written in Java which frees users from the hassles associated with platform/operating system-dependent installation and usage. PDB Editor can be downloaded from http://sourceforge.net/projects/pdbeditorjl/.
Synthesis, structural approach and electronic properties of V{sub 18}O{sub 45}, (N{sub 2}C{sub 6}H{sub 14}){sub 6}: a new organically templated vanadium oxide exhibiting V{sub 2}O{sub 5} layer topology

Energy Technology Data Exchange (ETDEWEB)

Sicard, M.; Maignan, A. [Laboratoire Crismat-ISMRa UMR 6508, 14 - Caen (France); Riou, D. [Universite de Versailles St Quentin, Institut Lavoisier UMR CNRS 8637, 78 - Versailles (France)

2002-02-01

V{sub 18}O{sub 45}, (N{sub 2}C{sub 6}H{sub 14}){sub 6} was hydrothermally synthesized in the form of thin platelets. Its structural approach was investigated by single crystal X-ray diffraction (non-centrosymmetric P2{sub 1} (No 4) monoclinic space group with a 10.7713(3) Angstrom, b = 11.2697(3) Angstrom, c = 29.7630(9) Angstrom, {beta} = 93.924(1) deg., V = 3604.4(2) Angstrom{sup 3}, Z = 2). V{sub 18}O{sub 45}, (N{sub 2}C{sub 6}H{sub 14}){sub 6} exhibits a lamellar structure built up from the stacking of vanadium oxide slabs between which the di-protonated 1,4-di-aza-bi-cyclo[2.2.2]octane organic cations are intercalated. The oxide layers are topologically similar to those encountered in the parent vanadium penta-oxide V{sub 2}O{sub 5} but exhibiting here a mixed valence V{sup IV}/V{sup V} with a ratio equal to 2. The electronic conductivity measurements performed on the crystals show that the resistivity curves are described by an Arrhenius law with an activation energy of 0.16 eV. (authors)
Using Whole Stream {delta}{sup 15}N Additions to Understand the Effects of Land Use Change on Stream Function

Energy Technology Data Exchange (ETDEWEB)

Deegan, L. A.; Neill, C.; Thomas, S.; Haupert, C. [Marine Biological Laboratory, Woods Hole, MA (United States); Victoria, R. L.; Krusche, A. V.; Ballester, M. V.R. [Centro de Energia Nuclear na Agricultura, Universidade de Sao Paulo, Sao Paulo (Brazil)

2013-05-15

In this paper we introduce an emerging new technique; the use of {delta}{sup 15}N stable isotope tracers to understand both short term and long term alterations in stream ecosystem nitrogen biogeochemistry and food web dynamics. The use of {delta}{sup 15}N isotopes to determine stream nitrogen cycling was developed in small tundra streams in Alaska (USA), but a network of researchers using similar technique has rapidly grown to answer questions about nitrogen cycling and stream food webs in a variety of ecosystem types and subject to human modifications. Here we provide an overview of some of the information that can be provided using stable isotope additions and describe the general approach of an isotope addition experiment. To illustrate the scope of isotope applicability some examples are provided of work undertaken in the Brazilian Amazon. (author)
Web servers and services for electrostatics calculations with APBS and PDB2PQR

Science.gov (United States)

Unni, Samir; Huang, Yong; Hanson, Robert; Tobias, Malcolm; Krishnan, Sriram; Li, Wilfred W.; Nielsen, Jens E.; Baker, Nathan A.

2011-01-01

APBS and PDB2PQR are widely utilized free software packages for biomolecular electrostatics calculations. Using the Opal toolkit, we have developed a Web services framework for these software packages that enables the use of APBS and PDB2PQR by users who do not have local access to the necessary amount of computational capabilities. This not only increases accessibility of the software to a wider range of scientists, educators, and students but it also increases the availability of electrostatics calculations on portable computing platforms. Users can access this new functionality in two ways. First, an Opal-enabled version of APBS is provided in current distributions, available freely on the web. Second, we have extended the PDB2PQR web server to provide an interface for the setup, execution, and visualization electrostatics potentials as calculated by APBS. This web interface also uses the Opal framework which ensures the scalability needed to support the large APBS user community. Both of these resources are available from the APBS/PDB2PQR website: http://www.poissonboltzmann.org/. PMID:21425296
Simulating dynamics of {delta}{sup 13}C of CO{sub 2} in the planetary boundary layer a boreal forest region: covariation between surface fluxes and atmospheric mixing

Energy Technology Data Exchange (ETDEWEB)

Chen, Baozhang; Chen, Jing M. [Univ. of Toronto, ON (Canada). Dept. of Geography; Tans, Pieter P. [National Oceanic and Atmospheric Administration, Boulder, CO (United States). Earth System Research Lab.; Huang, Lin [Environment Canada, Toronto, ON (Canada). Atmospheric Science and Technology Directorate

2006-11-15

Stable isotopes of CO{sub 2} contain unique information on the biological and physical processes that exchange CO{sub 2} between terrestrial ecosystems and the atmosphere. Ecosystem exchange of carbon isotopes with the atmosphere is correlated diurnally and seasonally with the planetary boundary layer (PBL) dynamics. The strength of this kind of covariation affects the vertical gradient of {delta}{sup 13}C and thus the global {delta}{sup 13}C distribution pattern. We need to understand the various processes involved in transport/diffusion of carbon isotope ratio in the PBL and between the PBL and the biosphere and the troposphere. In this study, we employ a one-dimensional vertical diffusion/transport atmospheric model (VDS), coupled to an ecosystem isotope model (BEPS-EASS) to simulate dynamics of {sup 13}CO{sub 2} in the PBL over a boreal forest region in the vicinity of the Fraserdale (FRD) tower (49 deg 52 min 29.9 sec N, 81 deg 34 min 12.3 sec W) in northern Ontario, Canada. The data from intensive campaigns during the growing season in 1999 at this site are used for model validation in the surface layer. The model performance, overall, is satisfactory in simulating the measured data over the whole course of the growing season. We examine the interaction of the biosphere and the atmosphere through the PBL with respect to {delta}{sup 13}C on diurnal and seasonal scales. The simulated annual mean vertical gradient of {delta}{sup 13}C in the PBL in the vicinity of the FRD tower was about 0.025% in 1999. The {delta}{sup 13}C vertical gradient exhibited strong diurnal (29%) and seasonal (71%) variations that do not exactly mimic those of CO{sub 2}. Most of the vertical gradient (96.5% {+-}) resulted from covariation between ecosystem exchange of carbon isotopes and the PBL dynamics, while the rest (3.5%{+-}) was contributed by isotopic disequilibrium between respiration and photosynthesis. This disequilibrium effect on {delta}{sup 13}C of CO{sub 2} dynamics in PBL
Simulating dynamics of (delta){sup 13}C of CO{sub 2} in the planetary boundary layer a boreal forest region: covariation between surface fluxes and atmospheric mixing

Energy Technology Data Exchange (ETDEWEB)

Chen, Baozhang; Chen, Jing M. [Univ. of Toronto, ON (Canada). Dept. of Geography; Tans, Pieter P. [National Oceanic and Atmospheric Administration, Boulder, CO (United States). Earth System Research Lab.; Huang, Lin [Environment Canada, Toronto, ON (Canada). Atmospheric Science and Technology Directorate

2006-11-15

Stable isotopes of CO{sub 2} contain unique information on the biological and physical processes that exchange CO{sub 2} between terrestrial ecosystems and the atmosphere. Ecosystem exchange of carbon isotopes with the atmosphere is correlated diurnally and seasonally with the planetary boundary layer (PBL) dynamics. The strength of this kind of covariation affects the vertical gradient of (delta){sup 13}C and thus the global (delta){sup 13}C distribution pattern. We need to understand the various processes involved in transport/diffusion of carbon isotope ratio in the PBL and between the PBL and the biosphere and the troposphere. In this study, we employ a one-dimensional vertical diffusion/transport atmospheric model (VDS), coupled to an ecosystem isotope model (BEPS-EASS) to simulate dynamics of {sup 13}CO{sub 2} in the PBL over a boreal forest region in the vicinity of the Fraserdale (FRD) tower (49 deg 52 min 29.9 sec N, 81 deg 34 min 12.3 sec W) in northern Ontario, Canada. The data from intensive campaigns during the growing season in 1999 at this site are used for model validation in the surface layer. The model performance, overall, is satisfactory in simulating the measured data over the whole course of the growing season. We examine the interaction of the biosphere and the atmosphere through the PBL with respect to (delta){sup 13}C on diurnal and seasonal scales. The simulated annual mean vertical gradient of (delta){sup 13}C in the PBL in the vicinity of the FRD tower was about 0.025% in 1999. The (delta){sup 13}C vertical gradient exhibited strong diurnal (29%) and seasonal (71%) variations that do not exactly mimic those of CO{sub 2}. Most of the vertical gradient (96.5% {+-}) resulted from covariation between ecosystem exchange of carbon isotopes and the PBL dynamics, while the rest (3.5%{+-}) was contributed by isotopic disequilibrium between respiration and photosynthesis. This disequilibrium effect on (delta){sup 13}C of CO{sub 2} dynamics in PBL
The Use of PDB database as a Tool for Biochemistry Active Learning of Undergraduate Students

Directory of Open Access Journals (Sweden)

T.M.F. Günther et al.

2017-07-01

Full Text Available Traditional Biochemistry teaching-learning is still an ongoing practice at UFSC. There are few published reports about innovative pedagogical practices of this discipline at this University. To ensure motivation through active learning of Basic Biochemistry we started to apply new methodologies back to 2005. This approach intended to stimulate undergraduate students in learning Biochemistry proactively. Objectives: Use PDB as a tool to improve skills related to Biochemistry education, while using specific information available; provide virtual data in order to stimulate student autonomy in active teaching-learning processes through methodologies based on the use of safe and suitable scientific information. Material and Methods: At the beginning, students were exposed to Biochemistry of Proteins content through traditional lectures. On the following stage, an introduction to PDB was made at the digital environment (http://www.rcsb.org/pdb/home/home.do depicting scientific information. Students received a model-instruction describing myoglobin characteristics at PDB (https://pdb101.rcsb.org/motm/1. This Powerpoint™ presentation gave clues on how the work was to be done. A lottery was made and each pair of students was allowed to select a protein and then developed Powerpoint™ presentations. Proteins were chosen from the PDB categories and obtained from the academic educational plan for Basic Biochemistry related to the Nutrition-Course. The Moodle plataform provided virtual materials, allowing full interactivity to all student presentations. Results and Discussion: There was total adherence to the pedagogical proposal. The student presentations in Powerpoint™ were adequate and made available to the attendees in the Moodle platform. Items surveyed in the presented script with the highest hit rates (grade ten were: biological importance (100%, amino acid composition (92.30%, structural information (89.75%, occurrence (89.74%, URL cited (79
Impact of carbohydrate supply on stem growth, wood and respired CO{sub 2} {delta}{sup 13}C : assessment by experimental girdling

Energy Technology Data Exchange (ETDEWEB)

Maunoury-Danger, F. [Paris-Sud Univ., Orsay Cedex (France). Laboratoire Ecologie, Systematique et Evolution; Centre National de la Recherche Scientifique, Orsay CEDEX (France); AgroParisTech, Paris (France); Paul Verlaine-Metz Univ., Metz (France). Laboratoire des Interactions Ecotoxicologie Biodiversite Ecosystemes; Fresneau, C.; Eglin, T.; Berveiller, D.; Francois, C.; Damesin, C. [Paris-Sud Univ., Orsay Cedex (France). Laboratoire Ecologie, Systematique et Evolution; Centre National de la Recherche Scientifique, Orsay CEDEX (France); AgroParisTech, Paris (France); Lelarge-Trouverie, C. [Paris-Sud Univ., Orsay Cedex (France). Inst. de Biotechnologie des Plantes, Plateforme Metabolisme-Metabolome

2010-07-15

In trees, carbohydrate storage and remobilization may affect the carbon isotope signals of sugars exported from leaves, tree organic matter and respired carbon dioxide (CO{sub 2}). This study characterized the impact of a change in the carbon (C) source used for stem functioning on the {delta}{sup 13} C of stem organic matter and respired CO{sub 2}. Girdling experiments were carried out on 2-year old oaks that consisted in removing the bark and phloem around the stem so that the sap would cease to flow. The stem was therefore forced to use its own C reserves to maintain metabolic activity. Trees were girdled at 3 different periods, notably just after budburst, during stem growth, and just after cessation of stem radial growth. Stem radial growth and respiration rate were measured throughout the year. Other measured variables included {delta}{sup 13} C of respired CO{sub 2} and contents of starch and water-soluble fraction in stems and leaves. The study showed that girdling stopped growth, even early in the growing season, leading to a decrease in stem CO{sub 2} efflux. The study demonstrated that leaf carbohydrate supply versus reserve use could be an important factor controlling stem growth and {delta}{sup 13} C of both ring and stem CO{sub 2} efflux. 69 refs., 3 tabs., 5 figs.
Houtman Abrolhos Isotope (delta 18O, delta 13C) Data for 1795 to 1994

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — DESCRIPTION: VARIABLES AND UNITS: Column #1: core depth in mm Column #2: delta C-13 vs V-PDB Column #3: delta O-18 vs V-PDB Column #4: assigned date in years A.D....
RCSB PDB Mobile: iOS and Android mobile apps to provide data access and visualization to the RCSB Protein Data Bank.

Science.gov (United States)

Quinn, Gregory B; Bi, Chunxiao; Christie, Cole H; Pang, Kyle; Prlić, Andreas; Nakane, Takanori; Zardecki, Christine; Voigt, Maria; Berman, Helen M; Bourne, Philip E; Rose, Peter W

2015-01-01

The Research Collaboratory for Structural Bioinformatics Protein Data Bank (RCSB PDB) resource provides tools for query, analysis and visualization of the 3D structures in the PDB archive. As the mobile Web is starting to surpass desktop and laptop usage, scientists and educators are beginning to integrate mobile devices into their research and teaching. In response, we have developed the RCSB PDB Mobile app for the iOS and Android mobile platforms to enable fast and convenient access to RCSB PDB data and services. Using the app, users from the general public to expert researchers can quickly search and visualize biomolecules, and add personal annotations via the RCSB PDB's integrated MyPDB service. RCSB PDB Mobile is freely available from the Apple App Store and Google Play (http://www.rcsb.org). © The Author 2014. Published by Oxford University Press.
Recommendations of the wwPDB NMR Validation Task Force

Science.gov (United States)

Montelione, Gaetano T.; Nilges, Michael; Bax, Ad; Güntert, Peter; Herrmann, Torsten; Richardson, Jane S.; Schwieters, Charles; Vranken, Wim F.; Vuister, Geerten W.; Wishart, David S.; Berman, Helen M.; Kleywegt, Gerard J.; Markley, John L.

2013-01-01

As methods for analysis of biomolecular structure and dynamics using nuclear magnetic resonance spectroscopy (NMR) continue to advance, the resulting 3D structures, chemical shifts, and other NMR data are broadly impacting biology, chemistry, and medicine. Structure model assessment is a critical area of NMR methods development, and is an essential component of the process of making these structures accessible and useful to the wider scientific community. For these reasons, the Worldwide Protein Data Bank (wwPDB) has convened an NMR Validation Task Force (NMR-VTF) to work with the wwPDB partners in developing metrics and policies for biomolecular NMR data harvesting, structure representation, and structure quality assessment. This paper summarizes the recommendations of the NMR-VTF, and lays the groundwork for future work in developing standards and metrics for biomolecular NMR structure quality assessment. PMID:24010715
Synthesis, thermal and electrical properties of Al-doped Bi{sub 4}V{sub 1.8}Cu{sub 0.2}O{sub 10.7}

Energy Technology Data Exchange (ETDEWEB)

Essalim, R.; Ammar, A.; Tanouti, B. [Laboratoire des Sciences des Matériaux Inorganiques et leurs Applications (LASMIA), Equipe Matériaux à Faible Dimensionnalité(EMAFAD), Faculté des Sciences, Semlalia, Av. My Abdellah, B.P. 2390 Marrakech (Morocco); Mauvy, F., E-mail: fabrice.mauvy@cnrs.fr [Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB) CNRS UPR 9048, Université de Bordeaux, 87, Av. Dr A. Schweitzer, 33608 Pessac (France)

2016-08-15

Partial substitution of copper with aluminum in Bi{sub 4}V{sub 1.8}Cu{sub 0.2}O{sub 10.7} has led to the Bi{sub 4}V{sub 1.8}Cu{sub 0.2−x}Al{sub x}O{sub 10.7+x/2} solid solution. X-ray diffraction and thermal analysis have shown that the compounds with x=0.05 and x=0.10 are tetragonal with γ′ form of Bi{sub 4}V{sub 2}O{sub 11}, while the compound with x=0.15 is of β polymorph. The effect of Al{sup 3+} doping on electrical conductivity has been studied using Electrochemical Impedance Spectroscopy. The electrical conductivity of doped samples along with the amount of Al{sup 3+} has been studied by electrochemical impedance spectroscopy in the temperature range 250–700 °C. The slope changes observed in the Arrhenius plots agree with the microstructural transitions occurring in these compounds. The highest ionic conductivity values are obtained for the sample with x=0.05. - Graphical abstract: Arrhenius plots of the electrical conductivity of the of Bi{sub 4}V{sub 1.8}Cu{sub 0.2−x}Al{sub x}O{sub 10.7+x/2} compounds. Display Omitted.
Electrochemically active MnO{sub 2} coated Li{sub 1.2}Ni{sub 0.18}Co{sub 0.04}Mn{sub 0.58}O{sub 2} cathode with highly improved initial coulombic efficiency

Energy Technology Data Exchange (ETDEWEB)

Jin, Yanling; Xu, Youlong, E-mail: ylxu@mail.xjtu.edu.cn; Sun, Xiaofei; Xiong, Lilong; Mao, Shengchun

2016-10-30

Highlights: • MnO{sub 2} was used to coat lithium-rich layered oxide Li{sub 1.2}Ni{sub 0.18}Co{sub 0.04}Mn{sub 0.58}O{sub 2}. • MnO{sub 2} is electrochemically active and became spinel phase after cycles. • MnO{sub 2}-coated material shows noticeably improved initial coulombic efficiency. • Specific capacities and rate performances could also be enhanced by MnO{sub 2} coating. - Abstract: Lithium-rich layered oxide is known to be one of the most promising positive electrode materials for lithium ion batteries due to its large capacity and high energy density. However, low initial coulombic efficiency is currently an urgent problem hindering its practical application. In this work, electrochemically active MnO{sub 2} coating was used to improve the coulombic efficiency of Li{sub 1.2}Ni{sub 0.18}Co{sub 0.04}Mn{sub 0.58}O{sub 2}. Firstly, the pristine material was synthesized via co-precipitation following by solid-state calcination. Then MnO{sub 2}-coated Li{sub 1.2}Ni{sub 0.18}Co{sub 0.04}Mn{sub 0.58}O{sub 2} was prepared by heat treatment of the mixture of pristine powder and manganese nitrate. During first discharging, lithium ions can intercalate into not only the delithiated Li{sub 1.2}Ni{sub 0.18}Co{sub 0.04}Mn{sub 0.58}O{sub 2} but also the MnO{sub 2} coating, thus noticeably improves the coulombic efficiency and discharge capacity. The initial efficiency is enhanced from 61.2% (pristine) to 84.4%, 88.8% and 95.4%, respectively, for 10 wt.%, 15 wt.% and 20 wt.% MnO{sub 2} coated Li{sub 1.2}Ni{sub 0.18}Co{sub 0.04}Mn{sub 0.58}O{sub 2} at 20 mA g{sup −1}. Furthermore, the 15 wt.% MnO{sub 2} coated sample delivers an initial discharge capacity as high as 294.4 mAh g{sup −1}.
Hexagonal perovskites with cationic vacancies. 11. Stacking polytype Ba/sub 6/W/sub 4/vacant/sub 2/O/sub 18/

Energy Technology Data Exchange (ETDEWEB)

Kemmler-Sack, S [Tuebingen Univ. (Germany, F.R.). Lehrstuhl fuer Anorganische Chemie 2

1979-07-01

The white Ba/sub 6/W/sub 4/vacant/sub 2/O/sub 18/, with a cation/vacancy ratio of 2:1 for the octahedral holes, is the first representative of a new stacking polytype for this formula type. It crystallizes in a rhombohedral six layer-structure with asub(hex) = 10.13 A; csub(hex) = 13.96 A; Z = 3 (rhosub(exp) = 7.3 g/cm/sup 3/; rhosub(calc) = 7.41 g/cm/sup 3/).
A tool for calculating binding-site residues on proteins from PDB structures

Directory of Open Access Journals (Sweden)

Hu Jing

2009-08-01

Full Text Available Abstract Background In the research on protein functional sites, researchers often need to identify binding-site residues on a protein. A commonly used strategy is to find a complex structure from the Protein Data Bank (PDB that consists of the protein of interest and its interacting partner(s and calculate binding-site residues based on the complex structure. However, since a protein may participate in multiple interactions, the binding-site residues calculated based on one complex structure usually do not reveal all binding sites on a protein. Thus, this requires researchers to find all PDB complexes that contain the protein of interest and combine the binding-site information gleaned from them. This process is very time-consuming. Especially, combing binding-site information obtained from different PDB structures requires tedious work to align protein sequences. The process becomes overwhelmingly difficult when researchers have a large set of proteins to analyze, which is usually the case in practice. Results In this study, we have developed a tool for calculating binding-site residues on proteins, TCBRP http://yanbioinformatics.cs.usu.edu:8080/ppbindingsubmit. For an input protein, TCBRP can quickly find all binding-site residues on the protein by automatically combining the information obtained from all PDB structures that consist of the protein of interest. Additionally, TCBRP presents the binding-site residues in different categories according to the interaction type. TCBRP also allows researchers to set the definition of binding-site residues. Conclusion The developed tool is very useful for the research on protein binding site analysis and prediction.
Sediment features, macrozoobenthic assemblages and trophic relationships ({delta}{sup 13}C and {delta}{sup 15}N analysis) following a dystrophic event with anoxia and sulphide development in the Santa Giusta lagoon (western Sardinia, Italy)

Energy Technology Data Exchange (ETDEWEB)

Magni, P. [CNR-IAMC National Research Council - Institute for Coastal Marine Environment c/o IMC - International Marine Centre, Loc. Sa Mardini, Torregrande, 09072 Oristano (Italy); IMC - International Marine Centre, Loc. Sa Mardini, Torregrande, 09072 Oristano (Italy)], E-mail: paolo.magni@iamc.cnr.it; Rajagopal, S. [Department of Animal Ecology and Ecophysiology, Institute for Water and Wetland Research, Radboud University Nijmegen, Toernooiveld, 6525 ED Nijmegen (Netherlands); Velde, G. van der [Department of Animal Ecology and Ecophysiology, Institute for Water and Wetland Research, Radboud University Nijmegen, Toernooiveld, 6525 ED Nijmegen (Netherlands); National Museum of Natural History Naturalis, P.O. Box 9517, 2300 RA Leiden (Netherlands); Fenzi, G. [IMC - International Marine Centre, Loc. Sa Mardini, Torregrande, 09072 Oristano (Italy); Kassenberg, J. [Department of Animal Ecology and Ecophysiology, Institute for Water and Wetland Research, Radboud University Nijmegen, Toernooiveld, 6525 ED Nijmegen (Netherlands); Vizzini, S.; Mazzola, A. [Dipartimento di Biologia Animale, Universita di Palermo, via Archirafi 18, 90123 Palermo (Italy); Giordani, G. [Dipartimento di Scienze Ambientali, Universita di Parma, Via Usberti 33/A, 43100 Parma (Italy)

2008-07-01

Macrozoobenthic assemblages and stable carbon ({delta}{sup 13}C) and nitrogen ({delta}{sup 15}N) isotope values of various primary producers (macroalgae and angiosperms) and consumers (macroinvertebrate filter/suspension feeders, deposit feeders, detritivores/omnivores and carnivores and fishes) were studied in the Santa Giusta lagoon (Sardinia, Italy) before (spring) and after (autumn) a dystrophic event which occurred in the summer of 2004. A few days after the dystrophy, the physico-chemical characteristics of sediments and macrozoobenthic assemblages were also investigated. In the latter occasion, high total organic carbon (3.9%) and organic matter (15.9%) contents of surface sediments went together with peaks in acid-volatile sulphide concentrations. Certain immediate effects were quite extreme, such as the drastic reduction in macrozoobenthos and the massive fish kill in August 2004. Among the macrozoobenthos, there were few individuals of chironomid larvae and Capitella cf. capitata left. However, by October, chironomid larvae were numerous, indicating a lack of predators (e.g. fish) and competitors. In addition, some bivalve species and polychaetes which were absent, or present in small numbers before the event, became relatively numerous. The results are discussed based on a knowledge of the sulphide tolerance of these species. Stable isotope analysis clearly showed that the basal level of the food web for most consumers consisted mainly of macroalgae and sedimentary organic matter, and that the values before and after the dystrophic event were not significantly different from one another. This indicates that the relations among different trophic levels were quickly restored following the dystrophic event.

PDB-NMA of a protein homodimer reproduces distinct experimental motility asymmetry

Science.gov (United States)

Tirion, Monique M.; ben-Avraham, Daniel

2018-03-01

We have extended our analytically derived PDB-NMA formulation, Atomic Torsional Modal Analysis or ATMAN (Tirion and ben-Avraham 2015 Phys. Rev. E 91 032712), to include protein dimers using mixed internal and Cartesian coordinates. A test case on a 1.3 {\\mathringA} resolution model of a small homodimer, ActVA-ORF6, consisting of two 112-residue subunits identically folded in a compact 50 {\\mathringA} sphere, reproduces the distinct experimental Debye-Waller motility asymmetry for the two chains, demonstrating that structure sensitively selects vibrational signatures. The vibrational analysis of this PDB entry, together with biochemical and crystallographic data, demonstrates the cooperative nature of the dimeric interaction of the two subunits and suggests a mechanical model for subunit interconversion during the catalytic cycle.
Rotationally resolved pulsed-field ionization photoelectron bands for O{sub 2}{sup +}(A {sup 2}{pi}{sub u},v{sup +}=0-12) in the energy range of 17.0-18.2 eV

Energy Technology Data Exchange (ETDEWEB)

Song, Y. [Ames Laboratory, U.S. Department of Energy and Department of Chemistry, Iowa State University, Ames, Iowa 50011 (United States); Evans, M. [Ames Laboratory, U.S. Department of Energy and Department of Chemistry, Iowa State University, Ames, Iowa 50011 (United States); Ng, C. Y. [Ames Laboratory, U.S. Department of Energy and Department of Chemistry, Iowa State University, Ames, Iowa 50011 (United States); Hsu, C.-W. [Chemical Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Jarvis, G. K. [Chemical Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2000-01-15

We have obtained rotationally resolved pulsed-field ionization photoelectron (PFI-PE) spectra for O{sub 2} in the energy range of 17.05-18.13 eV, covering the ionization transitions O{sub 2}{sup +}(A {sup 2}{pi}{sub u},v{sup +}=0-12,N{sup +})(<-)O{sub 2}(X {sup 3}{sigma}{sub g}{sup -},v{sup ''}=0,N{sup ''}). Although these O{sub 2}{sup +}(A {sup 2}{pi}{sub u},v{sup +}) PFI-PE bands have significant overlaps with vibrational bands for O{sub 2}{sup +}(a {sup 4}{pi}{sub u}) and O{sub 2}{sup +}(X {sup 2}{pi}{sub g}), we have identified all the O{sub 2}{sup +}(A {sup 2}{pi}{sub u},v{sup +}=0-12) bands by simulation of spectra obtained using supersonically cooled O{sub 2} samples with rotational temperatures {approx_equal}20 and 220 K. While these v{sup +}=0-12 PFI-PE bands represent the first rotationally resolved photoelectron data for O{sub 2}{sup +}(A {sup 2}{pi}{sub u}), the PFI-PE bands for O{sub 2}{sup +}(A {sup 2}{pi}{sub u},v{sup +}=9 and 10) are the first rotationally resolved spectroscopic data for these levels. The simulation also allows the determination of accurate ionization energies, vibrational constants, and rotational constants for O{sub 2}{sup +}(A {sup 2}{pi}{sub u},v{sup +}=0-12). The analysis of the PFI-PE spectra supports the conclusion of the previous emission study that the O{sub 2}{sup +}(A {sup 2}{pi}{sub u},v{sup +}=9 and 10) states are strongly perturbed by a nearby electronic state. (c) 2000 American Institute of Physics.
Synthesis of C{sub 60}(OH){sub 18-20} in aqueous alkaline solution under O{sub 2}-atmosphere

Energy Technology Data Exchange (ETDEWEB)

Alves, Gustavo Catao; Ladeira, Luiz Orlando; Righi, Ariete; Krambrock, Klaus; Pinheiro, Mauricio Veloso B. [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Dept. de Fisica; Calado, Hallen Daniel; Gil, Rossimiriam Pereira de Freitas [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Dept. de Quimica]. E-mail: gustavo.catao@terra.com.br

2006-09-15

In this work we report on an alternative synthesis of water-soluble fullerenes known as fullerols, aiming for biomedical applications. The synthesis is based on a process in which polyethylene glycol (PEG400) is used as phase-transfer catalyst between fullerene/benzene and aqueous NaOH solutions. The polyhydroxylation of the fullerenes occurs in the NaOH solution under a continuous flow of O{sub 2} to enhance the reaction yield. The resulting compound was characterized with infrared spectroscopy, nuclear magnetic resonance, thermo-gravimetric analysis and optical absorption. The formation of C{sub 60}(OH){sub 18-20} in high yields was confirmed. (author)
Oxygen 18 isotopic analysis of sub-glacial concentrations of the Laurentide Ice Sheet

Energy Technology Data Exchange (ETDEWEB)

Hillaire-Marcel, C [Quebec Univ., Montreal (Canada); Cailleux, A [Observatoire de Paris, Section de Meudon, 92 (France); Soucy, J

1979-07-01

Calcareous concretions occuring on Grenvillian gneiss have been discovered north of Hull, Quebec. Their structure and isotopic composition (delta/sub PDB//sup 18/O approximately equal to -26%; delta/sub PDB//sup 13/C approximately equal to 0%; /sup 14/C age > 35,000 BP) indicate subglacial conditions of precipitation. It is concluded that they were deposited at the base of the Laurentide ice sheet. Assuming equilibrium conditions with the subglacial film of water during precipitation of calcite, it is possible to define a -27.5 to -31.8% (vs. 'standard mean ocean water' (SMOW)) range for the oxygen-18 content of ice.
A novel organic–inorganic hybrid with Anderson type polyanions as building blocks: (C{sub 6}H{sub 10}N{sub 3}O{sub 2}){sub 2}Na(H{sub 2}O){sub 2}[Al(OH){sub 6}Mo{sub 6}O{sub 18}]·6H{sub 2}O

Energy Technology Data Exchange (ETDEWEB)

Thabet, Safa, E-mail: safathabet@hotmail.fr [Laboratoire de matériaux et cristallochimie, Département de chimie, Institut Supérieur des Sciences Appliquées et Technologier, Avenue El Mourouj, 5111 Mahdia (Tunisia); Ayed, Brahim, E-mail: brahimayed@yahoo.fr [Laboratoire de matériaux et cristallochimie, Département de chimie, Institut Supérieur des Sciences Appliquées et Technologier, Avenue El Mourouj, 5111 Mahdia (Tunisia); Haddad, Amor [Laboratoire de matériaux et cristallochimie, Département de chimie, Institut Supérieur des Sciences Appliquées et Technologier, Avenue El Mourouj, 5111 Mahdia (Tunisia)

2012-11-15

Graphical abstract: Display Omitted Highlights: ► Synthesis of a novel inorganic–organic hybrid compound based on Anderson polyoxomolybdates. ► Characterization by X-ray diffraction, IR and UV–Vis spectroscopies of the new compound. ► Potential applications in catalysis, biochemical analysis and electrical conductivity of the organic–inorganic compound. -- Abstract: A new organic–inorganic hybrid compound based on Anderson polyoxomolybdates, (C{sub 6}H{sub 10}N{sub 3}O{sub 2}){sub 2}Na(H{sub 2}O){sub 2}[Al(OH){sub 6}Mo{sub 6}O{sub 18}]·6H{sub 2}O (1) have been isolated by the conventional solution method and characterized by single-crystal X-ray diffraction, infrared, ultraviolet spectroscopy and Thermogravimetric Analysis (TGA). This compound crystallized in the triclinic system, space group P−1, with a = 94.635(1) Å, b = 10.958(1) Å, c = 11.602(1) Å, α = 67.525(1)°, β = 71.049(1)°, γ = 70.124(1)° and Z = 1. The crystal structures of the compounds exhibit three-dimensional supramolecular assembly based on the extensive hydrogen bonding interactions between organic cations, sodium cations, water molecules and Anderson polyoxoanions. The infrared spectrum fully confirms the X-ray crystal structure and the UV spectrum of the title compound exhibits an absorption peak at 210 nm.
Electronic structure of Ti/sub 2/O/sub 3/, V/sub 2/O/sub 3/, and Cr/sub 2/O/sub 3/

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Bondarenko, T N; Zhurakovskii, E A; Dzeganovskii, V P [AN Ukrainskoj SSR, Kiev. Inst. Problem Materialovedeniya

1975-11-01

Electronic structure of oxides Ti/sub 2/O/sub 3/, V/sub 2/O/sub 3/, Cr/sub 2/O/sub 3/ was elucidated by means of X-ray and ESCA methods and the results were compared with the data obtained by other methods and with the available models of electronic structures. Energy diagram of V/sub 2/O/sub 3/ and common energy scale of X-ray spectra of Ti and Cr in Ti/sub 2/O/sub 3/ and Cr/sub 2/O/sub 3/ are presented. X-ray spectra show that these oxides possess the states which are related genetically to the M4p-states i.e. the X-ray data complement essentially to the result of optical and electrophysical measurements. MO and M/sub 2/O/sub 3/ compounds in the region of Fermi level have overlapping emission and absorption spectra which is specific to the matters with the metallic type of bonding. Actually TiO, VO, Ti/sub 2/O/sub 3/ and V/sub 2/O/sub 3/ have metallic type of bonding. However such overlap was observed in Cr/sub 2/O/sub 3/ as well whose forbidden zone according to photoconductivity measurments is about 3 eV. Absence of energy gap between emission and absorption spectra in Cr/sub 2/O/sub 3/ may be explained by traces of impurities which convert dielectrics conductors - impurities act as agents caus:ng filling or generation of vacancies rather than independent allowing additives. On the other hand this may be due to the defects in Cr/sub 2/O/sub 3/ lattice which may cause appearance of excited states in forbidden zone. These investigations enable to draw energy diagram of V/sub 2/O/sub 3/ and to combine the spectra of M in Ti/sub 2/O/sub 3/ into common energy scheme. Analysis of the diagram and combined spectra revealed great similarity in the electronic structures of M/sub 2/O/sub 3/ oxides (M - Ti, V, Cr) .
Spatial Distribution of Stable Isotopes of Precipitation in Kumamoto, Japan

Energy Technology Data Exchange (ETDEWEB)

Anoue, M. T.; Shimada, J. [Graduate School of Science and Technology, Kumamoto University (Japan); Ichiyanagi, K. [Graduate School of Science and Technology, Kumamoto University and Japan Agency for Marine-Earth Science and Technology (Japan)

2013-07-15

To understand the spatial distribution of stable isotopic compositions in precipitation, precipitation samples were collected every two weeks from november 2009 to december 2010 at 6 points in Kumamoto, Japan. The {delta}{sup 18}O and {delta}{sup 2}H of precipitation samples were measured by isotope ratio mass spectrometry (Delta-S) with CO{sub 2}/H2{sub O} equivalent method for {delta}{sup 18}O and the chromium reduction method for {delta}2H. The range of {delta}{sup 18}O and d-excess (= {delta}{sup 2}H - 8 {delta}{sup 18}O) in precipitation is from -13.4 per mille to -3.5 per mille and from 2.6 per mille to 35.6 per mille , respectively. Seasonal variability of {delta}{sup 18}O (d-excess) in precipitation was low (high) in winter and high (low) in summer. The seasonal wind of this study area was dominated by south-westerly in summer (from June to August) and north-westerly in winter (from December to February). These wind regimes indicate seasonal variabilities of the water vapour pathway from the origin. In this paper the trend of inland effect to the {delta}{sup 18}O for both south-westerly and north-westerly are also considered. As a result, significant correlation between distances from the coastal line at south-westerly or north-westerly and {delta}{sup 18}O in precipitation was recognized, particularly from 18 February to 7 March and from 29 September to 19 October in 2010 (statistically significant with 5% level). Furthermore, in order to evaluate the course of precipitation, the column total of water vapour flux was considered in the whole period by using JRA-25 and JCDAS. It is interesting that the inland effect corresponded to the column total of water vapour flux at south-westerly (north-westerly). Hence, it is conceivable that the spatial distribution of {delta}{sup 18}O in precipitation was controlled by a column total of water vapour flux in this area. (author)
Ferroelectric, magnetic and structural studies of the Bi{sub 4}LaSmFe{sub 2}Ti{sub 3}O{sub 18} multiferroic material

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Alarcón-Suesca, C.E. [Fachgebiet Synthese und Charakterisierung Innovatiert Materialien, Chemistry Department, Technische Universität München, Lichtenbergstrasse D-85748, Garching (Germany); Grupo de Física de Nuevos Materiales, Departamento de Física, Universidad Nacional de Colombia, AA 5997 Bogotá DC (Colombia); Cardona-Vásquez, J.A. [Grupo de Física de Nuevos Materiales, Departamento de Física, Universidad Nacional de Colombia, AA 5997 Bogotá DC (Colombia); Salcedo-Fontecha, J.P.; Vargas-Jiménez, A. [Maestría en Ciencias Física, Departamento de Física, Universidad Nacional de Colombia, AA 5997 Bogotá DC (Colombia); Landínez-Téllez, D.A.; Roa-Rojas, J. [Grupo de Física de Nuevos Materiales, Departamento de Física, Universidad Nacional de Colombia, AA 5997 Bogotá DC (Colombia)

2014-12-15

We report the synthesis and characterization of the new Bi{sub 4}LaSmFe{sub 2}Ti{sub 3}O{sub 18} ferroelectric ceramic. X-ray characterization reveals reflections for layered perovskite Aurivillius system. Rietveld analyses of the powder pattern shows that Bi{sub 4}LaSmFe{sub 2}Ti{sub 3}O{sub 18} crystallizes in orthorhombic structure, which corresponds to the space group F2/mm (#42), with lattice parameters a=5.4240(16) Ǻ, b=5.4078(23) Ǻ and c=50.2440(12) Ǻ. Scanning electron microscopy (SEM) reveals the formation of dense material with plate-like morphology. Electric polarization curves were measured by means of a radiant ferroelectric tester, at room temperature in bulk samples and exhibit an intrinsic ferroelectric response, even at low applied fields. Measurements of the magnetization as a function of temperature after Zero field cooling and field cooling were carried out by using a MPMS Quantum Design SQUID magnetometer. We found an effective magnetic moment of 7.95 µB, which is 95.8% in agreement with the expected value calculated from Hund's rules. Magnetization curves as the function of applied fields reveal an incipient hysteretic behavior at room temperature.
CH4 fluxes across the seafloor at three district gas hydrate fields: Impacts on ocean and atmosphere chemistry

Energy Technology Data Exchange (ETDEWEB)

Kastner, M.; Bartlett, D.; MacDonald, I.; Solomon, E.

2005-07-01

The role of methane hydrate in the global methane budget is poorly documented because relatively little is known about the transport of methane through the seafloor into the ocean and atmosphere, and the extent of en route water-column methanotrophy. Pore fluids and water column samples within and adjacent to methane plumes were analyzed for methane, dissolved inorganic C (DIC), sulfide/sulfate, alkalinity, and major element concentrations, and for delta{sup 13}C-CH4 and DIC, at three distinct gas hydrate environments. The three environments are: Bush Hill (BH) in the northern Gulf of Mexico (GOM), Eel River (ER) offshore Northern California, and North and South Hydrate Ridges (HR), Cascadia, Oregon margin. The methane source at these sites ranges from mostly thermogenic at GOM to primarily biogenic at HR. At these three distinct gas hydrate environments, at all the sites a significant enrichment in {sup 13}C-CH4 along isopycnals away from the methane plumes is observed, indicating extensive aerobic bacterial methane oxidation in the water column, and correspondingly of oxygen consumption. This is principally pronounced in the mostly biogenic methane setting. The delta{sup 13}C-CH4 values range from approx. 12 to -67 , PDB, at the Hydrate Ridges, from approx. 34 to -52 at Eel River, and from approx. 41 to -67 at Bush Hill. The large variation in methane C isotope ranges between the sites suggests that major differences exist in both the rates of aerobic methane oxidation and system openness at the studied locations. Methane fluxes across the sediment/seawater interface were measured, with a flux meter, MOSQUITO (Multiple Orifice Sampler and Quantitative Injection Tracer Observers) only at BH (Solomon et al., 2005). Water column methane concentrations are on average lower at HR than at ER and GOM. Preliminary estimates suggests that aerobic oxidation is nearly complete, consumes most to all of the water column methane at HR, but at the GOM only approx. 80% to a
A global analysis of NMR distance constraints from the PDB

International Nuclear Information System (INIS)

Vranken, Wim

2007-01-01

Information obtained from Nuclear Magnetic Resonance (NMR) experiments is encoded as a set of constraint lists when calculating three-dimensional structures for a protein. With the amount of constraint data from the world wide Protein Data Bank (wwPDB) that is now available, it is possible to do a global, large-scale analysis using only information from the constraints, without taking the coordinate information into account. This article describes such an analysis of distance constraints from NOE data based on a set of 1834 NMR PDB entries containing 1909 protein chains. In order to best represent the quality and extent of the data that is currently deposited at the wwPDB, only the original data as deposited by the authors was used, and no attempt was made to 'clean up' and further interpret this information. Because the constraint lists provide a single set of data, and not an ensemble of structural solutions, they are easier to analyse and provide a reduced form of structural information that is relevant for NMR analysis only. The online resource resulting from this analysis makes it possible to check, for example, how often a particular contact occurs when assigning NOESY spectra, or to find out whether a particular sequence fragment is likely to be difficult to assign. In this respect it formalises information that scientists with experience in spectrum analysis are aware of but cannot necessarily quantify. The analysis described here illustrates the importance of depositing constraints (and all other possible NMR derived information) along with the structure coordinates, as this type of information can greatly assist the NMR community
Pharmacophore searching: A potential solution for correcting unknown ligands (UNK) labelling errors in Protein Data Bank (PDB'S).

Science.gov (United States)

Ibrahim, Musadiq; Lapthorn, Adrian Jonathan; Ibrahim, Mohammad

2017-08-01

The Protein Data Bank (PDB) is the single most important repository of structural data for proteins and other biologically relevant molecules. Therefore, it is critically important to keep the PDB data, error-free as much as possible. In this study, we have critically examined PDB structures of 292 protein molecules which have been deposited in the repository along with potentially incorrect ligands labelled as Unknown ligands (UNK). Pharmacophores were generated for all the protein structures by using Discovery Studio Visualizer (DSV) and Accelrys, Catalyst ® . The generated pharmacophores were subjected to the database search containing the reported ligand. Ligands obtained through Pharmacophore searching were then checked for fitting the observed electron density map by using Coot ® . The predicted ligands obtained via Pharmacophore searching fitted well with the observed electron density map, in comparison to the ligands reported in the PDB's. Based on our study we have learned that till may 2016, among 292 submitted structures in the PDB, at least 20 structures have ligands with a clear electron density but have been incorrectly labelled as unknown ligands (UNK). We have demonstrated that Pharmacophore searching and Coot ® can provide potential help to find suitable known ligands for these protein structures, the former for ligand search and the latter for electron density analysis. The use of these two techniques can facilitate the quick and reliable labelling of ligands where the electron density map serves as a reference. Copyright © 2017 Elsevier Inc. All rights reserved.
IDENTIFYING PLANETARY BIOSIGNATURE IMPOSTORS: SPECTRAL FEATURES OF CO AND O{sub 4} RESULTING FROM ABIOTIC O{sub 2}/O{sub 3} PRODUCTION

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Schwieterman, Edward W.; Meadows, Victoria S.; Arney, Giada N.; Luger, Rodrigo; Misra, Amit; Barnes, Rory [Astronomy Department, University of Washington, Box 351580, Seattle, WA 98195 (United States); Domagal-Goldman, Shawn D.; Deming, Drake; Harman, Chester E., E-mail: eschwiet@uw.edu [NASA Astrobiology Institute’s Virtual Planetary Laboratory, Seattle, WA 981195 (United States)

2016-03-01

O{sub 2} and O{sub 3} have been long considered the most robust individual biosignature gases in a planetary atmosphere, yet multiple mechanisms that may produce them in the absence of life have been described. However, these abiotic planetary mechanisms modify the environment in potentially identifiable ways. Here we briefly discuss two of the most detectable spectral discriminants for abiotic O{sub 2}/O{sub 3}: CO and O{sub 4}. We produce the first explicit self-consistent simulations of these spectral discriminants as they may be seen by James Webb Space Telescope (JWST). If JWST-NIRISS and/or NIRSpec observe CO (2.35, 4.6 μm) in conjunction with CO{sub 2} (1.6, 2.0, 4.3 μm) in the transmission spectrum of a terrestrial planet it could indicate robust CO{sub 2} photolysis and suggest that a future detection of O{sub 2} or O{sub 3} might not be biogenic. Strong O{sub 4} bands seen in transmission at 1.06 and 1.27 μm could be diagnostic of a post-runaway O{sub 2}-dominated atmosphere from massive H-escape. We find that for these false positive scenarios, CO at 2.35 μm, CO{sub 2} at 2.0 and 4.3 μm, and O{sub 4} at 1.27 μm are all stronger features in transmission than O{sub 2}/O{sub 3} and could be detected with S/Ns ≳ 3 for an Earth-size planet orbiting a nearby M dwarf star with as few as 10 transits, assuming photon-limited noise. O{sub 4} bands could also be sought in UV/VIS/NIR reflected light (at 0.345, 0.36, 0.38, 0.445, 0.475, 0.53, 0.57, 0.63, 1.06, and 1.27 μm) by a next generation direct-imaging telescope such as LUVOIR/HDST or HabEx and would indicate an oxygen atmosphere too massive to be biologically produced.
Stable isotope geochemistry of deep sea cherts

Energy Technology Data Exchange (ETDEWEB)

Kolodny, Y; Epstein, S [California Inst. of Tech., Pasadena (USA). Div. of Geological Sciences

1976-10-01

Seventy four samples of DSDP (Deep Sea Drilling Project) recovered cherts of Jurassic to Miocene age from varying locations, and 27 samples of on-land exposed cherts were analyzed for the isotopic composition of their oxygen and hydrogen. These studies were accompanied by mineralogical analyses and some isotopic analyses of the coexisting carbonates. delta/sup 18/0 of chert ranges between 27 and 39 parts per thousand relative to SMOW, delta/sup 18/0 of porcellanite - between 30 and 42 parts per thousand. The consistent enrichment of opal-CT in porcellanites in /sup 18/0 with respect to coexisting microcrystalline quartz in chert is probably a reflection of a different temperature (depth) of diagenesis of the two phases. delta/sup 18/0 of deep sea cherts generally decrease with increasing age, indicating an overall cooling of the ocean bottom during the last 150 m.y. A comparison of this trend with that recorded by benthonic foraminifera (Douglas et al., Initial Reports of the Deep Sea Drilling Project; 32:509(1975)) indicates the possibility of delta/sup 18/0 in deep sea cherts not being frozen in until several tens of millions of years after deposition. Cherts of any Age show a spread of delta/sup 18/0 values, increasing diagenesis being reflected in a lowering of delta/sup 18/0. Drusy quartz has the lowest delta/sup 18/0 values. On land exposed cherts are consistently depleted in /sup 18/0 in comparison to their deep sea time equivalent cherts. Water extracted from deep sea cherts ranges between 0.5 and 1.4 wt%. deltaD of this water ranges between -78 and -95 parts per thousand and is not a function of delta/sup 18/0 of the cherts (or the temperature of their formation).
Removal of diethyl phthalate from water solution by adsorption, photo-oxidation, ozonation and advanced oxidation process (UV/H{sub 2}O{sub 2}, O{sub 3}/H{sub 2}O{sub 2} and O{sub 3}/activated carbon)

Energy Technology Data Exchange (ETDEWEB)

Medellin-Castillo, Nahum A. [Centro de Investigacion y Estudios de Posgrado, Facultad de Ingenieria, Universidad Autonoma de San Luis Potosi, Av. Dr. M. Nava No.6, San Luis de Potosi, 78290 (Mexico); Ocampo-Perez, Raul [Centro de Investigacion y Estudios de Posgrado, Facultad de Ciencias Quimicas, Universidad Autonoma de San Luis Potosi, San Luis Potosi, 78290 (Mexico); Departamento de Quimica Inorganica, Facultad de Ciencias, Universidad de Granada, 18071, Granada (Spain); Leyva-Ramos, Roberto [Centro de Investigacion y Estudios de Posgrado, Facultad de Ciencias Quimicas, Universidad Autonoma de San Luis Potosi, San Luis Potosi, 78290 (Mexico); Sanchez-Polo, Manuel [Departamento de Quimica Inorganica, Facultad de Ciencias, Universidad de Granada, 18071, Granada (Spain); Rivera-Utrilla, Jose, E-mail: jrivera@ugr.es [Departamento de Quimica Inorganica, Facultad de Ciencias, Universidad de Granada, 18071, Granada (Spain); Mendez-Diaz, Jose D. [Departamento de Quimica Inorganica, Facultad de Ciencias, Universidad de Granada, 18071, Granada (Spain)

2013-01-01

The objective of this work was to compare the effectiveness of conventional technologies (adsorption on activated carbon, AC, and ozonation) and technologies based on advanced oxidation processes, AOPs, (UV/H{sub 2}O{sub 2}, O{sub 3}/AC, O{sub 3}/H{sub 2}O{sub 2}) to remove phthalates from aqueous solution (ultrapure water, surface water and wastewater). Diethyl phthalate (DEP) was chosen as a model pollutant because of its high water solubility (1080 mg/L at 293 K) and toxicity. The activated carbons showed a high adsorption capacity to adsorb DEP in aqueous solution (up to 858 mg/g), besides the adsorption mechanism of DEP on activated carbon is governed by dispersive interactions between {pi} electrons of its aromatic ring with {pi} electrons of the carbon graphene planes. The photodegration process showed that the pH solution does not significantly affect the degradation kinetics of DEP and the first-order kinetic model satisfactorily fitted the experimental data. It was observed that the rate of decomposition of DEP with the O{sub 3}/H{sub 2}O{sub 2} and O{sub 3}/AC systems is faster than that with only O{sub 3}. The technologies based on AOPs (UV/H{sub 2}O{sub 2}, O{sub 3}/H{sub 2}O{sub 2}, O{sub 3}/AC) significantly improve the degradation of DEP compared to conventional technologies (O{sub 3}, UV). AC adsorption, UV/H{sub 2}O{sub 2}, O{sub 3}/H{sub 2}O{sub 2}, and O{sub 3}/AC showed a high yield to remove DEP; however, the disadvantage of AC adsorption is its much longer time to reach maximum removal. The best system to treat water (ultrapure and natural) polluted with DEP is the O{sub 3}/AC one since it achieved the highest DEP degradation and TOC removal, as well as the lower water toxicity. -- Highlights: Black-Right-Pointing-Pointer Activated carbons showed a high adsorption capacity (up to 858 mg/g) to remove DEP. Black-Right-Pointing-Pointer The pH solution did not significantly affect the photodegradation kinetics of DEP. Black
Pooled versus separate measurements of tree-ring stable isotopes

Energy Technology Data Exchange (ETDEWEB)

Dorado Linan, Isabel, E-mail: isabel@gfz-potsdam.de [Universitat de Barcelona, Departament d' Ecologia, Diagonal 645, 08028, Barcelona (Spain); German Centre for Geosciences, Climate Dynamics and Landscape Evolution, Dendro Laboratory, Telegrafenberg, 14473, Potsdam (Germany); Gutierrez, Emilia, E-mail: emgutierrez@ub.edu [Universitat de Barcelona, Departament d' Ecologia, Diagonal 645, 08028, Barcelona (Spain); Helle, Gerhard, E-mail: ghelle@gfz-potsdam.de [German Centre for Geosciences, Climate Dynamics and Landscape Evolution, Dendro Laboratory, Telegrafenberg, 14473, Potsdam (Germany); Heinrich, Ingo, E-mail: heinrich@gfz-potsdam.de [German Centre for Geosciences, Climate Dynamics and Landscape Evolution, Dendro Laboratory, Telegrafenberg, 14473, Potsdam (Germany); Andreu-Hayles, Laia, E-mail: laiandreu@ub.edu [Universitat de Barcelona, Departament d' Ecologia, Diagonal 645, 08028, Barcelona (Spain); Tree-Ring Laboratory, Lamont-Doherty Earth Observatory of Columbia University, Palisades NY (United States); Planells, Octavi, E-mail: leocarpus@hotmail.com [Universitat de Barcelona, Departament d' Ecologia, Diagonal 645, 08028, Barcelona (Spain); Leuenberger, Markus, E-mail: leuenberger@climate.unibe.ch [Climate and Environmental Physics, Physics Institute, University of Bern, Sidlerstrasse 5, 3012 Bern (Switzerland); Oeschger Centre of Climate Change Research, University of Bern, Zaehringerstrasse 25, 3012 Bern (Switzerland); Buerger, Carmen, E-mail: buerger@gfz-potsdam.de [German Centre for Geosciences, Climate Dynamics and Landscape Evolution, Dendro Laboratory, Telegrafenberg, 14473, Potsdam (Germany); Schleser, Gerhard, E-mail: schleser@gfz-potsdam.de [German Centre for Geosciences, Climate Dynamics and Landscape Evolution, Dendro Laboratory, Telegrafenberg, 14473, Potsdam (Germany)

2011-05-01

{delta}{sup 13}C and {delta}{sup 18}O of tree rings contain time integrated information about the environmental conditions weighted by seasonal growth dynamics and are well established as sources of palaeoclimatic and ecophysiological data. Annually resolved isotope chronologies are frequently produced by pooling dated growth rings from several trees prior to the isotopic analyses. This procedure has the advantage of saving time and resources, but precludes from defining the isotopic error or statistical uncertainty related to the inter-tree variability. Up to now only a few studies have compared isotope series from pooled tree rings with isotopic measurements from individual trees. We tested whether or not the {delta}{sup 13}C and the {delta}{sup 18}O chronologies derived from pooled and from individual tree rings display significant differences at two locations from the Iberian Peninsula to assess advantages and constraints of both methodologies. The comparisons along the period 1900-2003 reveal a good agreement between pooled chronologies and the two mean master series which were created by averaging raw individual values (Mean) or by generating a mass calibrated mean (MassC). In most of the cases, pooled chronologies show high synchronicity with averaged individual samples at interannual scale but some differences also show up especially when comparing {delta}{sup 18}O decadal to multi-decadal variations. Moreover, differences in the first order autocorrelation among individuals may be obscured by pooling strategies. The lack of replication of pooled chronologies prevents detection of a bias due to a higher mass contribution of one sample but uncertainties associated with the analytical process itself, as sample inhomogeneity, seems to account for the observed differences. - Research Highlights: {yields} Pooled {delta}{sup 13}C and {delta}{sup 18}O chronologies are expected to be similar to the mean. {yields} Empirical pooled chronologies {delta}{sup 13}C and
Microstructural morphologies of slag based glass-ceramics nucleated with 5 wt% Cr{sub 2}O{sub 3} and 5 wt% Cr{sub 2}O{sub 3} + 5 wt% TiO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Oevecoglu, M.L.; Oezkal, B. [Istanbul Technical Univ. (Turkey). Dept. of Metallurgical and Materials Enginering; Catakli, E. [Mimar Sinan Univ., Istanbul (Turkey). Faculty of Science and Literature; Erkmen, Z.E. [Istnabul Univ. (Turkey). Dept. of Metallurgical Engineering

2002-07-01

Glass-ceramic materials were developed from the blast-furnace slags by mixing 5 wt% Cr{sub 2}O{sub 3} and 5 wt% Cr{sub 2}O{sub 3} + 5 wt% TiO{sub 2}. The samples were nucleated for 18 h at 780 C and crystallized for 20 min. at 905 C, respectively. SEM and SEM/EDS investigations revealed the presence of clover-shaped TiO{sub 2} particles in the glassy matrix of the sample nucleated with 5 wt% Cr{sub 2}O{sub 3} + 5 wt% TiO{sub 2} and polygonal-shaped Cr{sub 2}O{sub 3} platelets for both samples. XRD scans revealed the presence of akermanite (2CaO.MgO.2SiO{sub 2}) and gehlenite (2CaO.Al{sub 2}O{sub 3}.SiO{sub 2}) peaks indicating the existence of the mellilite solid solution for the crystallized glass-ceramic samples. (orig.)
Synthesis and characterization of the lead borate Pb{sub 6}B{sub 12}O{sub 21}(OH){sub 6}

Energy Technology Data Exchange (ETDEWEB)

Schoenegger, Sandra; Ortner, Teresa S.; Wurst, Klaus; Heymann, Gunter; Huppertz, Hubert [Innsbruck Univ. (Austria). Inst. fuer Allgemeine, Anorganische und Theoretische Chemie

2016-11-01

A lead borate with the composition Pb{sub 6}B{sub 12}O{sub 21}(OH){sub 6} was synthesized through a hydrothermal synthesis, using lead metaborate in combination with sodium nitrate and potassium nitrate. The compound crystallizes in the trigonal, non-centrosymmetric space group P3{sub 2} (no. 145) with the lattice parameters a = 1176.0(4), c = 1333.0(4) pm, and V = 0.1596(2) nm{sup 3}. Interestingly, the data of Pb{sub 6}B{sub 12}O{sub 21}(OH){sub 6} correct the structure of a literature known lead borate with the composition ''Pb{sub 6}B{sub 11}O{sub 18}(OH){sub 9}''. For the latter compound, nearly identical lattice parameters of a = 1176.91(7) and c = 1333.62(12) pm were reported, possessing a crystal structure, in which the localization and refinement of one boron atom was obviously overlooked. The structure of Pb{sub 6}B{sub 12}O{sub 21}(OH){sub 6} is built up from trigonal planar BO{sub 3} and tetrahedral BO{sub 4} groups forming complex chains. The Pb{sup 2+} cations are located between neighboring polyborate chains. The here reported compound Pb{sub 6}B{sub 12}O{sub 21}(OH){sub 6} and ''Pb{sub 6}B{sub 11}O{sub 18}(OH){sub 9}'' were, however, produced under different synthesis conditions. While ''Pb{sub 6}B{sub 11}O{sub 18}(OH){sub 9}'' was synthesized via a hydrothermal synthesis including ethylenediamine and acetic acid, the here reported lead borate Pb{sub 6}B{sub 12}O{sub 21}(OH){sub 6} could be obtained under moderate hydrothermal conditions (240 C) without the addition of organic reagents.
Can pelagic net heterotrophy account for carbon fluxes from eastern Canadian lakes?

Energy Technology Data Exchange (ETDEWEB)

Dubois, Kristal, E-mail: kristal.dubois@gmail.com [Ottawa-Carleton Geoscience Center, University of Ottawa, 140 Louis Pasteur, Ottawa, Ontario, K1N 6N5 (Canada); Carignan, Richard [Departement des Sciences Biologiques, Universite de Montreal C.P. 6128, succ. Centre-Ville, Montreal, Quebec, H3C 3J7 (Canada); Veizer, Jan [Ottawa-Carleton Geoscience Center, University of Ottawa, 140 Louis Pasteur, Ottawa, Ontario, K1N 6N5 (Canada)

2009-05-15

Lakes worldwide are commonly oversaturated with CO{sub 2}, however the source of this CO{sub 2} oversaturation is not well understood. To examine the magnitude of the C flux to the atmosphere and determine if an excess of respiration (R) over gross primary production (GPP) is sufficient to account for this C flux, metabolic parameters and stable isotopes of dissolved O{sub 2} and C were measured in 23 Quebec lakes. All of the lakes sampled were oversaturated with CO{sub 2} over the sampling period, on average 221 {+-} 25%. However, little evidence was found to conclude that this CO{sub 2} oversaturation was the result of an excess of pelagic R over GPP. In lakes Croche and a l'Ours, where CO{sub 2} flux, R and GPP were measured weekly, the annual difference between pelagic GPP and R, or net primary production (NPP), was not sufficient to account for the size of the CO{sub 2} flux to the atmosphere. In Lac Croche average annual NPP was 14.4 mg C m{sup -2} d{sup -1} while the average annual flux of CO{sub 2} to the atmosphere was 34 mg C m{sup -2} d{sup -1}. In Lac a l'Ours average annual NPP was -9.1 mg C m{sup -2} d{sup -1} while the average annual flux of CO{sub 2} to the atmosphere was 55 mg C m{sup -2} d{sup -1}. In all of the lakes sampled, O{sub 2} saturation averaged 104.0 {+-} 1.7% during the ice-free season and the isotopic composition of dissolved O{sub 2} ({delta}{sup 18}O{sub DO}) was 22.9 {+-} 0.3 per mille , lower than atmospheric values and indicative of net autotrophy. Carbon evasion was not a function of R, nor did the isotopic signature of dissolved CO{sub 2} in the lakes present evidence of excess R over GPP. External inputs of C must therefore subsidize the lake to explain the continued CO{sub 2} oversaturation. The isotopic composition of dissolved inorganic C ({delta}{sup 13}C{sub DIC}) indicates that the CO{sub 2} oversaturation cannot be attributed to in situ aerobic respiration. {delta}{sup 13}C{sub DIC} reveals a source of excess
Estimation of precipitation rates by measurements of {sup 36}Cl in the GRIP ice core with the PSI/ETH tandem accelerator

Energy Technology Data Exchange (ETDEWEB)

Wagner, G.; Baumgartner, S.; Beer, J. [EAWAG, Duebendorf (Switzerland); Synal, H.A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Suter, M. [Eidgenoessische Technische Hochschule, Zurich (Switzerland)

1997-09-01

Within the European Greenland ice core project (GRIP) {sup 36}Cl AMS measurements have been performed on ice core samples from Summit (Greenland, 73{sup o}N, 37{sup o}W). Most data analysed so far are from the lower part of the ice core. The {sup 36}Cl concentration is well correlated with {delta}{sup 18}O, which is considered as a proxy for paleotemperatures. Assuming that the deposition rate of radionuclides is independent of {delta}{sup 18}O, {sup 36}Cl is used to estimate the relationship between accumulation and {delta}{sup 18}O. The results confirm that the rapid changes of {delta}{sup 18}O, the so-called Dansgaard-Oeschger events, are also reflected in the precipitation rate. (author) 1 fig., 3 refs.
Glass formation and properties of glasses in V/sub 2/O/sub 5/-B/sub 2/O/sub 3/-P/sub 2/O/sub 5/ system

Energy Technology Data Exchange (ETDEWEB)

Sedmale, G P; Vajvad, Ya A; Arkhipova, S E; Laukmanis, L A

1987-01-01

The glass formation in the system V/sub 2/O/sub 5/-B/sub 2/O/sub 3/-P/sub 2/O/sub 5/ and the properties of the obtained glasses have been studied by methods including that of the mathematical design and the treatment of the obtained data on ECM. The glass formation region is limited by the molar content of V/sub 2/O/sub 5/ 30-80%, B/sub 2/O/sub 3/ 0-45%, P/sub 2/O/sub 5/ 20-65%. The chemical stability data show that at the molar content of V/sub 2/O/sub 5/ 45-50% the transfer of vanadium from the state of the modificator to the glass-forming agent takes place. For the studied glasses the electron mechanism of conductivity is the dominating one.

High-pressure behavior and equations of state of the cobaltates YBaCo{sub 4}O{sub 7}, YBaCo{sub 4}O{sub 7+{delta}}, YBaCoZn{sub 3}O{sub 7} and BaCoO{sub 3-x}

Energy Technology Data Exchange (ETDEWEB)

Juarez-Arellano, Erick A., E-mail: eajuarez@unpa.edu.mx [Instituto de Quimica Aplicada, Universidad del Papaloapan, Circuito Central 200, Parque Industrial, 68301 Tuxtepec, Oaxaca (Mexico); Avdeev, Maxim; Yakovlev, Sergey [Bragg Institute, ANSTO, PMB 1, Menai, NSW 2234 (Australia); Lopez-de-la-Torre, Laura; Bayarjargal, Lkhamsuren; Winkler, Bjoern; Friedrich, Alexandra [Institut fuer Geowissenschaften, Goethe-Universitaet Frankfurt, Altenhoeferallee 1, 60438 Frankfurt a.M. (Germany); Kharton, Vladislav V. [Department of Materials and Ceramic Engineering, CICECO, University of Aveiro, 3810-193 Aveiro (Portugal)

2012-12-15

The compressibilities of the cobaltates YBaCo{sub 4}O{sub 7}, YBaCo{sub 4}O{sub 7+{delta}}, YBaCoZn{sub 3}O{sub 7} and BaCoO{sub 3-x} were investigated by in situ powder X-ray diffraction experiments up to 30 GPa using diamond anvil cells. Pressure-induced phase transitions and amorphization were observed in all the samples. The onset of the pressure-induced phase transition and the onset of the amorphization were observed at {approx}11.7 and 12.2 GPa (YBaCo{sub 4}O{sub 7}), at {approx}14.2 and 16.1 GPa (YBaCo{sub 4}O{sub 7+{delta}}), and at {approx}16.7 and 18.7 GPa (YBaCoZn{sub 3}O{sub 7}), respectively. An attempt to laser anneal at high-pressure failed as it led to a decomposition of the YBaCo{sub 4}O{sub 7} phase into a mixture of phases. Fits of second- and third-order Birch-Murnaghan equations-of-state to the p-V data result in B{sub 0}=109(3) GPa for YBaCo{sub 4}O{sub 7}; B{sub 0}=186(4) GPa and B Prime =1.5 for YBaCo{sub 4}O{sub 7+{delta}}; and B{sub 0}=117(1) GPa for YBaCoZn{sub 3}O{sub 7}. The high-pressure behavior of the studied compounds was compared with isostructural compounds and it is shown that the oxygen-content has a very large effect on the high-pressure behavior of this class of materials. Highlights: Black-Right-Pointing-Pointer Compressibilities were investigated by in situ DAC powder X-ray diffraction experiments. Black-Right-Pointing-Pointer Pressure-induced phase transitions were observed in all the samples. Black-Right-Pointing-Pointer High-pressure phases were very sensitive to small amounts of stresses and strains. Black-Right-Pointing-Pointer Due to the metastability of the compounds, laser annealing leads to decomposition. Black-Right-Pointing-Pointer Oxygen-content has a very large effect on the high pressure behavior in these materials.
Radiocarbon dating of VIRI bone samples using ultrafiltration

Energy Technology Data Exchange (ETDEWEB)

Minami, Masayo, E-mail: minami@nendai.nagoya-u.ac.jp [Center for Chronological Research, Nagoya University, Nagoya 464-8602 (Japan); Yamazaki, Kana [Faculty of Science, Nagoya University, Nagoya 464-8602 (Japan); Omori, Takayuki [University Museum, University of Tokyo, Tokyo 113-0033 (Japan); Nakamura, Toshio [Center for Chronological Research, Nagoya University, Nagoya 464-8602 (Japan)

2013-01-15

Ultrafiltration can effectively remove low-molecular-weight (LMW) contaminants from bone gelatin to extract high-molecular-weight (HMW) proteins that are derived from original bone collagen, though it cannot remove HMW collagen crosslinked with humic acids. Therefore, ultrafiltration is often used to obtain more accurate {sup 14}C dates of bones. However, ultrafiltration may introduce new contaminants to bone gelatins, mainly from ultrafilters used. To study the effects of ultrafiltration on {sup 14}C age, we analyzed the C/N ratio, {delta}{sup 13}C{sub PDB} and {delta}{sup 15}N{sub AIR} values, and {sup 14}C ages of acid-soluble bone collagen obtained by decalcification, gelatin extracted from acid-insoluble bone collagen, and the HMW gelatin and LMW fractions produced during ultrafiltration of the extracted gelatin. Bone samples from the Fifth International Radiocarbon Intercomparison (VIRI) were used: VIRI-E (mammoth), -F (horse), -G (human), and -I (whale). In this study, carbon and nitrogen content and gelatin yields were used to evaluate collagen preservation in the VIRI bone samples. Radiocarbon ages, {delta}{sup 13}C{sub PDB} and {delta}{sup 15}N{sub AIR} values of unfiltered and HMW gelatins were obtained and compared with the published consensus values. The LMW fraction was found to exhibit different values from those of the other fractions, indicating the possible presence of extraneous contamination. The Vivaspin Trade-Mark-Sign 6 ultrafilters used in this study were analyzed and radiocarbon dated both before and after cleaning. We present evidence to suggest that LMW fraction contaminants could be derived from the ultrafilters rather than humic substances. Excessively long ultrafiltration time was suspected to have contaminated the bone samples with material from the ultrafilter, because those samples exhibited older {sup 14}C ages than did those filtered for shorter durations. The results in this study indicate that {sup 14}C ages of unfiltered
Temperature and vital effect controls on Bamboo coral (Isididae) isotopegeochemistry: A test of the "lines method"

Energy Technology Data Exchange (ETDEWEB)

Hill, T M; Spero, H J; Guilderson, T P; LaVigne, M; Clague, D; Macalello, S; Jang, N

2011-03-01

Deep-sea bamboo corals hold promise as long-term climatic archives, yet little information exists linking bamboo coral geochemistry to measured environmental parameters. This study focuses on a suite of 10 bamboo corals collected from the Pacific and Atlantic basins (250-2136 m water depth) to investigate coral longevity, growth rates, and isotopic signatures. Calcite samples for stable isotopes and radiocarbon were collected from the base the corals, where the entire history of growth is recorded. In three of the coral specimens, samples were also taken from an upper branch for comparison. Radiocarbon and growth band width analyses indicate that the skeletal calcite precipitates from ambient dissolved inorganic carbon and that the corals live for 150-300 years, with extension rates of 9-128 {micro}m/yr. A linear relationship between coral calcite {delta}{sup 18}O and {delta}{sup 13}C indicates that the isotopic composition is influenced by vital effects ({delta}{sup 18}O:{delta}{sup 13}C slope of 0.17-0.47). As with scleractinian deep-sea corals, the intercept from a linear regression of {delta}{sup 18}O versus {delta}{sup 13}C is a function of temperature, such that a reliable paleotemperature proxy can be obtained, using the 'lines method.' Although the coral calcite {delta}{sup 18}O:{delta}{sup 13}C slope is maintained throughout the coral base ontogeny, the branches and central cores of the bases exhibit {delta}{sup 18}O:{delta}{sup 13}C values that are shifted far from equilibrium. We find that a reliable intercept value can be derived from the {delta}{sup 18}O:{delta}{sup 13}C regression of multiple samples distributed throughout one specimen or from multiple samples within individual growth bands.
Oxygen isotopic ratios of quartz from wind-erosive soils of southwestern United States in relation to aerosol dust

Energy Technology Data Exchange (ETDEWEB)

Sridhar, K.; Jackson, M.L.; Clayton, R.N.; Gillette, D.A.; Hawley, J.W.

1978-01-01

The oxygen isotopic ratios (expressed as parts per thousand relative to mean ocean water, SMOW, delta/sup 18/O) of the quartz from 13 soils undergoing much wind erosion during the study period of 1972-1975 in four southwestern states and from comparison areas were determined. The delta/sup 18/O for quartz from eight Texas (TX) and Arizona (AZ) soils range from 13.0 to 15.9 /sup 0///sub 00/. The quartz of the sands and silts coarser than 20 ..mu..m from three of the soils had delta/sup 18/O values ranging from 13.1 to 15.1 /sup 0///sub 00/, characteristic of an ultimate igneous-metamorphic origin. The delta/sup 18/O values increase greatly with decreasing particle size of quartz from three soils ranging from loamy fine sand to loam to clay in texture. The delta/sup 18/O of the 1-10 ..mu..m quartz fraction (aerosol size) ranged from 19.2 to 20.2 /sup 0///sub 00/ (19.55 +- 0.28 /sup 0///sub 00/; +- sigma) for the thirteen soils most affected by dust storms. The oxygen isotopic ratios of 1-10 ..mu..m quartz from three Hawaiian soils and two sediments from Lake Waiau occurring at 3,970 m altitude on the Mauna Kea summit on the Island of Hawaii give a delta/sup 18/O mean of 18.3 +- 0.2 /sup 0///sub 00/.
Synthesis, characterization, and comparative gas-sensing properties of Fe{sub 2}O{sub 3} prepared from Fe{sub 3}O{sub 4} and Fe{sub 3}O{sub 4}-chitosan

Energy Technology Data Exchange (ETDEWEB)

Cuong, Nguyen Duc [Faculty of Hospitality and Tourism, Hue University, 22 Lam Hoang, Vy Da Ward, Hue City (Viet Nam); College of Sciences, Hue University, 77 Nguyen Hue, Phu Nhuan Ward, Hue City (Viet Nam); International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (HUST), Hanoi (Viet Nam); Hoa, Tran Thai; Khieu, Dinh Quang [College of Sciences, Hue University, 77 Nguyen Hue, Phu Nhuan Ward, Hue City (Viet Nam); Lam, Tran Dai [Institute of Materials Science, Vietnamese Academy of Science and Technology, Hanoi (Viet Nam); Hoa, Nguyen Duc [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (HUST), Hanoi (Viet Nam); Van Hieu, Nguyen, E-mail: hieu@itims.edu.vn [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (HUST), Hanoi (Viet Nam)

2012-05-15

Highlights: Black-Right-Pointing-Pointer We have demonstrated a facile method to prepare Fe{sub 3}O{sub 4} nanoparticles and chitosan-coated Fe{sub 3}O{sub 4} nanoparticles. Black-Right-Pointing-Pointer {alpha}-Fe{sub 2}O{sub 3} sensors prepared from those Fe{sub 3}O{sub 4} materials have been investigated and compared. Black-Right-Pointing-Pointer The results show potential application of {alpha}-Fe{sub 2}O{sub 3} for CO sensors in environmental monitoring. - Abstract: In this paper, Fe{sub 3}O{sub 4} and chitosan (CS)-coated Fe{sub 3}O{sub 4} nanoparticles were synthesized via co-precipitation method and subsequent covalent binding of CS onto the surface for functionalization, respectively. Characterization of the crystal structures and morphologies of as-synthesized nanoparticles by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy demonstrated that Fe{sub 3}O{sub 4} had a cubic spinal structure with irregular shapes and average diameters of 10-20 nm. The surface states and magnetic properties of Fe{sub 3}O{sub 4}-CS nanoparticles were characterized by Fourier transform infrared spectra and vibrating sample magnetometry. Results showed that Fe{sub 3}O{sub 4}-CS nanoparticles possessed super-paramagnetic properties, with saturated magnetization up to 60 emu/g. In addition, Fe{sub 3}O{sub 4} and CS-coated Fe{sub 3}O{sub 4} nanoparticles were used in the fabrication of {alpha}-Fe{sub 2}O{sub 3} based gas sensors. Gas sensing measurements revealed that the {alpha}-Fe{sub 2}O{sub 3} gas sensor prepared from Fe{sub 3}O{sub 4}-CS had a better response to H{sub 2}, CO, C{sub 2}H{sub 5}OH, and NH{sub 3} compared with the device prepared from pristine Fe{sub 3}O{sub 4}. Furthermore, the {alpha}-Fe{sub 2}O{sub 3} sensor prepared from Fe{sub 3}O{sub 4}-CS nanoparticles exhibited the highest response to CO among the test gases, suggesting that it has great potential for practical applications in environmental monitoring.
Structure and crystallization kinetics of Bi{sub 2}O{sub 3}-B{sub 2}O{sub 3} glasses

Energy Technology Data Exchange (ETDEWEB)

Cheng Yin [College of Materials Science and Engineering, Hunan University, Changsha, Hunan 410082 (China); Xiao Hanning [College of Materials Science and Engineering, Hunan University, Changsha, Hunan 410082 (China)]. E-mail: zjbcy@126.com; Guo Wenming [College of Materials Science and Engineering, Hunan University, Changsha, Hunan 410082 (China); Guo Weiming [College of Materials Science and Engineering, Hunan University, Changsha, Hunan 410082 (China)

2006-05-15

The experimental IR (infrared spectra) and differential scanning calorimetry (DSC) curves of Bi{sub 2}O{sub 3}-B{sub 2}O{sub 3} glasses, containing 30-60 mol% Bi{sub 2}O{sub 3}, have been investigated in the article. The composition dependence of IR absorption suggests that addition of Bi{sub 2}O{sub 3} results in a change in the short-range order structure of the borate matrix. The increase of Bi{sub 2}O{sub 3} content causes a progressive conversion of [BO{sub 3}] to [BO{sub 4}] units. Bi{sub 2}O{sub 3}, in the form of [BiO{sub 6}] octahedral units, plays the role of glass former. The crystallization kinetics of Bi{sub 2}O{sub 3}-B{sub 2}O{sub 3} glasses were described by thermal stability indexes (k {sub gl}, {delta}T), activation energy (E) for crystallization and numerical factors(n, m) depending on the nucleation process and growth morphology, which were calculated by Satava method and the modified Ozawa-Chen method. When Bi{sub 2}O{sub 3} {<=} 45 mol%, the increase of Bi{sub 2}O{sub 3} tends to improve the thermal stabilities of the glasses. In this case, k {sub gl} may be more suitable for estimating the glass thermal stability in above composition range than {delta}T. A further increase of Bi{sub 2}O{sub 3} content will increase the crystallization trends of investigated glasses. Two possible kinds of growth mechanisms were involved in Bi{sub 2}O{sub 3}-B{sub 2}O{sub 3} glasses: one-dimensional growth and two-dimensional growth. Moreover, structures of crystallized glasses were observed by X-ray diffraction (XRD). BiBO{sub 3} crystal with special non-linear optical properties can be obtained when Bi{sub 2}O{sub 3} {>=} 50 mol%.
Photoluminescence properties of the Eu-doped alpha-Al{sub 2}O{sub 3} microspheres

Energy Technology Data Exchange (ETDEWEB)

Liu, Dianguang, E-mail: dianguang12@gmail.com [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, West Youyi Rd., No. 127, Xi’an, Shaanxi 710072 (China); Science and Technology on Thermostructure Composite Materials Laboratory, Northwestern Polytechnical University, West Youyi Rd., No. 127, Xi’an, Shaanxi 710072 (China); Zhu, Zhenfeng [School of Materials Science and Engineering, Shaanxi University of Science and Technology, Xi’an 710021 (China)

2014-01-15

Highlights: • Al{sub 2}O{sub 3}:Eu{sup 3+} phosphors were prepared via a microwave solvothermal route. • The particles were hierarchically nanostructured microspheres packaged by nanosheets. • The powders presented excellent orange–red emission when excited at 393 nm. • Critical concentration and distance of Eu{sup 3+} in Al{sub 2}O{sub 3} is 0.007, 18 Å, respectively. -- Abstract: Al{sub 2}O{sub 3}:Eu{sup 3+} samples were synthesized via microwave solvothermal method and thermal decomposition of Eu{sup 3+} doped precursors. The sample characterizations were carried out by means of X-ray diffraction (XRD), scanning electron microscope (SEM) and photoluminescence (PL) spectra. XRD results indicated that Eu{sup 3+} doped samples were most of α-Al{sub 2}O{sub 3} phase after being calcined at 1473 K. SEM results showed that the obtained α-Al{sub 2}O{sub 3} based powders via microwave solvothermal method were microspheres with an average diameter about 1.6 μm. PL spectra showed that upon excitation at 393 nm, the orange–red emission bands at the wavelength longer than 560 nm were from {sup 5}D{sub 0} → {sup 7}F{sub J} (J = 1, 2) transitions. The asymmetry ratio of ({sup 5}D{sub 0} → {sup 7}F{sub 2})/({sup 5}D{sub 0} → {sup 7}F{sub 1}) intensity is about 1 and this value suggests that Eu{sup 3+} ions occupy the same ratio of symmetry and asymmetry sites. It is shown that the 0.7 mol% of doping concentration of Eu{sup 3+} ions in α-Al{sub 2}O{sub 3}:Eu{sup 3+} is optimum. According to Dexter’s theory, the critical distance between Eu{sup 3+} ions for energy transfer was determined to be 18 Å.
A stable isotope study of serpentinization in the Fengtien ophiolite, Taiwan

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Tzen-Fu Yui; Hsueh-Wen Yeh (Univ. of Hawaii, Honolulu (USA)); Chihming Wang Lee (National Taiwan Univ. (Taiwan))

1990-05-01

Detailed H- and O-isotopic studies of serpentinites of Fengtien ophiolite have been made in order to enhance our knowledge on the process of serpentinization. Pseudomorphic lizardites have {delta}{sup 18}O = +3.6{per thousand} and {delta}D = {minus}48 to {minus}49{per thousand}; bladed-mat and foliated antigorites have {delta}{sup 18}O = +3.5 to +5.8{per thousand} and {delta}D = {minus}45 to {minus}69{per thousand}; slickensided antigorites have {delta}{sup 18}O = +4.1 to +4.9{per thousand} and {delta}D = {minus}46 to {minus}50{per thousand}; picrolites have {delta}{sup 18}O = +4.2 to +4.3{per thousand} and {delta}D = {minus}65 to {minus}67{per thousand}; and slickensided chrysotiles have {delta}{sup 18}O = +4.1 to +4.5{per thousand} and {delta}D = {minus}80{per thousand}. It is suggested that lizardite might have formed in an oceanic environment, whereas antigorite and chrysotile have formed in continental environments. These results depict complicated multiple serpentinization processes. Isotopic temperatures calculated using {delta}{sup 18}O values of coexisting fissure-filling minerals range from 325 to 370{degree}C, which are consistent with those derived from phase equilibria involving serpentines. The narrow range of {delta}{sup 18}O and wide range of {delta}D values for antigorite and chrysotile also demonstrate that water/rock ratios during these serpentinizations should not have been high. These Fengtien serpentines fall outside either of the continental domains described by Wenner and Taylor (1973, 1974); and fall within their oceanic domain. We suggest that the domains proposed by Wenner and Taylor (1973, 1974) should be extended and that the terms, especially the continental antigorite and the continental lizardite-chrysotile, should be purely occurrence-descriptive.
Proteins of unknown function in the Protein Data Bank (PDB): an inventory of true uncharacterized proteins and computational tools for their analysis.

Science.gov (United States)

Nadzirin, Nurul; Firdaus-Raih, Mohd

2012-10-08

Proteins of uncharacterized functions form a large part of many of the currently available biological databases and this situation exists even in the Protein Data Bank (PDB). Our analysis of recent PDB data revealed that only 42.53% of PDB entries (1084 coordinate files) that were categorized under "unknown function" are true examples of proteins of unknown function at this point in time. The remainder 1465 entries also annotated as such appear to be able to have their annotations re-assessed, based on the availability of direct functional characterization experiments for the protein itself, or for homologous sequences or structures thus enabling computational function inference.
Proteins of Unknown Function in the Protein Data Bank (PDB: An Inventory of True Uncharacterized Proteins and Computational Tools for Their Analysis

Directory of Open Access Journals (Sweden)

Nurul Nadzirin

2012-10-01

Full Text Available Proteins of uncharacterized functions form a large part of many of the currently available biological databases and this situation exists even in the Protein Data Bank (PDB. Our analysis of recent PDB data revealed that only 42.53% of PDB entries (1084 coordinate files that were categorized under “unknown function” are true examples of proteins of unknown function at this point in time. The remainder 1465 entries also annotated as such appear to be able to have their annotations re-assessed, based on the availability of direct functional characterization experiments for the protein itself, or for homologous sequences or structures thus enabling computational function inference.
Comparison of P-containing {gamma}-Al{sub 2}O{sub 3} supported Ni-Mo bimetallic carbide, nitride and sulfide catalysts for HDN and HDS of gas oils derived from Athabasca bitumen

Energy Technology Data Exchange (ETDEWEB)

Sundaramurthy, V.; Dalai, A.K. [Catalysis and Chemical Reaction Engineering Laboratories, Department of Chemical Engineering, University of Saskatchewan, Saskatoon, SK (Canada); Adjaye, J. [Syncrude Edmonton Research Centre, Edmonton, AB (Canada)

2006-09-01

Phosphorus containing {gamma}-Al{sub 2}O{sub 3} supported bimetallic Ni-Mo carbide, nitride and sulfide catalysts have been synthesized from an oxide precursor containing 12.73wt.% Mo, 2.54wt.% Ni and 2.38wt.% P and characterized by elemental analysis, pulsed CO chemisorption, surface area measurements, X-ray diffraction, temperature-programmed reduction and DRIFT spectroscopy of CO adsorption. DRIFT spectroscopy of adsorbed CO on activated catalysts showed that carbide and nitride catalysts have surface exposed sites of Mo{sup o+} (0delta}}{sup +} (0<{delta}<2) sites respectively, and these sites are susceptible to sulfidation with H{sub 2}S/H{sub 2} mixture at 370{sup o}C. The hydrodenitrogenation (HDN) and hydrodesulfurization (HDS) activities of the bimetallic Ni-Mo carbide, nitride and sulfide catalysts were compared against commercial Ni-Mo/Al{sub 2}O{sub 3} catalyst in a trickle bed reactor using light gas oil and heavy gas oil derived from Athabasca bitumen in the temperature range 340-370 and 375-400{sup o}C respectively at 8.8MPa. The gradual transformation of Ni-Mo carbide and nitride phases into Ni-Mo sulfide phases was observed during precoking period, and the formed Ni-Mo sulfide phases enhanced the HDN and HDS activities of carbide and nitride catalysts. The {gamma}-Al{sub 2}O{sub 3} supported Ni-Mo bimetallic sulfide catalyst was found to be more active for HDN and HDS of light gas oil and heavy gas oil than the corresponding carbide and nitride catalysts on the basis of unit weight. (author)
Inhaled ozone (O{sub 3})-induces changes in serum metabolomic and liver transcriptomic profiles in rats

Energy Technology Data Exchange (ETDEWEB)

Miller, Desinia B. [Curriculum in Toxicology, University of North Carolina-Chapel Hill, Chapel Hill, NC (United States); Karoly, Edward D.; Jones, Jan C. [Metabolon Incorporation, Durham, NC (United States); Ward, William O.; Vallanat, Beena D.; Andrews, Debora L. [Research Cores Unit, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC (United States); Schladweiler, Mette C.; Snow, Samantha J. [Environmental Public Health Division, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC (United States); Bass, Virginia L. [Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC (United States); Richards, Judy E.; Ghio, Andrew J.; Cascio, Wayne E.; Ledbetter, Allen D. [Environmental Public Health Division, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC (United States); Kodavanti, Urmila P., E-mail: kodavanti.urmila@epa.gov [Environmental Public Health Division, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC (United States)

2015-07-15

Air pollution has been linked to increased incidence of diabetes. Recently, we showed that ozone (O{sub 3}) induces glucose intolerance, and increases serum leptin and epinephrine in Brown Norway rats. In this study, we hypothesized that O{sub 3} exposure will cause systemic changes in metabolic homeostasis and that serum metabolomic and liver transcriptomic profiling will provide mechanistic insights. In the first experiment, male Wistar Kyoto (WKY) rats were exposed to filtered air (FA) or O{sub 3} at 0.25, 0.50, or 1.0 ppm, 6 h/day for two days to establish concentration-related effects on glucose tolerance and lung injury. In a second experiment, rats were exposed to FA or 1.0 ppm O{sub 3}, 6 h/day for either one or two consecutive days, and systemic metabolic responses were determined immediately after or 18 h post-exposure. O{sub 3} increased serum glucose and leptin on day 1. Glucose intolerance persisted through two days of exposure but reversed 18 h-post second exposure. O{sub 3} increased circulating metabolites of glycolysis, long-chain free fatty acids, branched-chain amino acids and cholesterol, while 1,5-anhydroglucitol, bile acids and metabolites of TCA cycle were decreased, indicating impaired glycemic control, proteolysis and lipolysis. Liver gene expression increased for markers of glycolysis, TCA cycle and gluconeogenesis, and decreased for markers of steroid and fat biosynthesis. Genes involved in apoptosis and mitochondrial function were also impacted by O{sub 3}. In conclusion, short-term O{sub 3} exposure induces global metabolic derangement involving glucose, lipid, and amino acid metabolism, typical of a stress–response. It remains to be examined if these alterations contribute to insulin resistance upon chronic exposure. - Highlights: • Ozone, an ubiquitous air pollutant induces acute systemic metabolic derangement. • Serum metabolomic approach provides novel insights in ozone-induced changes. • Ozone exposure induces leptinemia
Fuel densification study about uranium- 7% nanostructured gadolinium (Gd{sub 2}O{sub 3}); Estudo da densificacao do combustivel uranio - 7% gadolinio (Gd{sub 2}O{sub 3}) nanoestruturado

Energy Technology Data Exchange (ETDEWEB)

Serafim, Antonio da Costa

2016-11-01

The sintering process of UO{sub 2}-Gd{sub 2}O{sub 3} pellets has been investigated in this work for its importance in the nuclear industry and for its complex behavior during sintering. Sintering blockage occurs from 1300 deg C upwards, when densification is shifted toward higher temperatures and the final density obtained is decreased. This research includes the development of nuclear fuel for power reactors in order to increase its efficiency inside the reactor core by raising the burnup. The use of nanosized Gd{sub 2}O{sub 3} was studied in the range from 10 to 30nm, which was added to UO{sub 2}, trying to verify the occurrence of characteristic sintering blockage due to Kirkendall sintering effect observed in previous research. The samples were produced by dry mechanical mixture of UO{sub 2} powder and 7% Gd{sub 2}O{sub 3} (macro- and nanostructured). The powders were compacted and the pellets were sintered at 1700 deg C under H{sub 2} atmosphere. These results indicate that the characteristic blockage during sintering in macrostructured system UO{sub 2}-Gd{sub 2}O{sub 3} occurred in the temperature range of 1300-1500 deg C, which slows down the densification. It was observed a less intense effect when using the nanostructured Gd{sub 2}O{sub 3}; it took place at the temperature of 900 deg C, then facilitating to get an additional densification. The dilatometric tests indicated shrinkage of 22, 18 and 20% respectively in UO{sub 2} pellets, macrostructured UO{sub 2}-7% Gd{sub 2}O{sub 3} and nanostructured UO{sub 2}-7%Gd{sub 2}O{sub 3}. We detected 2% higher shrinkage, when nanostructured Gd{sub 2}O{sub 3} was used instead of macrostructured Gd{sub 2}O{sub 3}, which is used commercially. Then, the nanostructured results showed more adequate density for nuclear fuel usage. (author)
Continuous mutual improvement of macromolecular structure models in the PDB and of X-ray crystallographic software: the dual role of deposited experimental data

International Nuclear Information System (INIS)

Terwilliger, Thomas C.; Bricogne, Gerard

2014-01-01

Macromolecular structures deposited in the PDB can and should be continually reinterpreted and improved on the basis of their accompanying experimental X-ray data, exploiting the steady progress in methods and software that the deposition of such data into the PDB on a massive scale has made possible. Accurate crystal structures of macromolecules are of high importance in the biological and biomedical fields. Models of crystal structures in the Protein Data Bank (PDB) are in general of very high quality as deposited. However, methods for obtaining the best model of a macromolecular structure from a given set of experimental X-ray data continue to progress at a rapid pace, making it possible to improve most PDB entries after their deposition by re-analyzing the original deposited data with more recent software. This possibility represents a very significant departure from the situation that prevailed when the PDB was created, when it was envisioned as a cumulative repository of static contents. A radical paradigm shift for the PDB is therefore proposed, away from the static archive model towards a much more dynamic body of continuously improving results in symbiosis with continuously improving methods and software. These simultaneous improvements in methods and final results are made possible by the current deposition of processed crystallographic data (structure-factor amplitudes) and will be supported further by the deposition of raw data (diffraction images). It is argued that it is both desirable and feasible to carry out small-scale and large-scale efforts to make this paradigm shift a reality. Small-scale efforts would focus on optimizing structures that are of interest to specific investigators. Large-scale efforts would undertake a systematic re-optimization of all of the structures in the PDB, or alternatively the redetermination of groups of structures that are either related to or focused on specific questions. All of the resulting structures should be
Continuous mutual improvement of macromolecular structure models in the PDB and of X-ray crystallographic software: the dual role of deposited experimental data

Energy Technology Data Exchange (ETDEWEB)

Terwilliger, Thomas C., E-mail: terwilliger@lanl.gov [Los Alamos National Laboratory, Mail Stop M888, Los Alamos, NM 87507 (United States); Bricogne, Gerard, E-mail: terwilliger@lanl.gov [Global Phasing Ltd, Sheraton House, Castle Park, Cambridge CB3 0AX (United Kingdom); Los Alamos National Laboratory, Mail Stop M888, Los Alamos, NM 87507 (United States)

2014-10-01

Macromolecular structures deposited in the PDB can and should be continually reinterpreted and improved on the basis of their accompanying experimental X-ray data, exploiting the steady progress in methods and software that the deposition of such data into the PDB on a massive scale has made possible. Accurate crystal structures of macromolecules are of high importance in the biological and biomedical fields. Models of crystal structures in the Protein Data Bank (PDB) are in general of very high quality as deposited. However, methods for obtaining the best model of a macromolecular structure from a given set of experimental X-ray data continue to progress at a rapid pace, making it possible to improve most PDB entries after their deposition by re-analyzing the original deposited data with more recent software. This possibility represents a very significant departure from the situation that prevailed when the PDB was created, when it was envisioned as a cumulative repository of static contents. A radical paradigm shift for the PDB is therefore proposed, away from the static archive model towards a much more dynamic body of continuously improving results in symbiosis with continuously improving methods and software. These simultaneous improvements in methods and final results are made possible by the current deposition of processed crystallographic data (structure-factor amplitudes) and will be supported further by the deposition of raw data (diffraction images). It is argued that it is both desirable and feasible to carry out small-scale and large-scale efforts to make this paradigm shift a reality. Small-scale efforts would focus on optimizing structures that are of interest to specific investigators. Large-scale efforts would undertake a systematic re-optimization of all of the structures in the PDB, or alternatively the redetermination of groups of structures that are either related to or focused on specific questions. All of the resulting structures should be
In{sub 2}O{sub 3}/Bi{sub 2}Sn{sub 2}O{sub 7} heterostructured nanoparticles with enhanced photocatalytic activity

Energy Technology Data Exchange (ETDEWEB)

Xing, Yonglei [Electronic Materials Research Laboratory, International Center for Dielectric Research, Key Laboratory of the Ministry of Education, School of Electronic and Information Engineering, State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, Shaanxi (China); Que, Wenxiu, E-mail: wxque@mail.xjtu.edu.cn [Electronic Materials Research Laboratory, International Center for Dielectric Research, Key Laboratory of the Ministry of Education, School of Electronic and Information Engineering, State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, Shaanxi (China); Yin, Xingtian; He, Zuoli; Liu, Xiaobin; Yang, Yawei; Shao, Jinyou [Electronic Materials Research Laboratory, International Center for Dielectric Research, Key Laboratory of the Ministry of Education, School of Electronic and Information Engineering, State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, Shaanxi (China); Kong, Ling Bing, E-mail: ELBKong@ntu.edu.sg [School of Materials Science and Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798 (Singapore)

2016-11-30

Highlights: • Visible-light photocatalytic activities of the nanostructured In{sub 2}O{sub 3}/Bi{sub 2}Sn{sub 2}O{sub 7} heterostructures were studied. • Effect of In{sub 2}O{sub 3} content on the photocatalytic activity of the In{sub 2}O{sub 3}/Bi{sub 2}Sn{sub 2}O{sub 7} heterostructure was evaluated. • 0.1In{sub 2}O{sub 3}/Bi{sub 2}Sn{sub 2}O{sub 7} heterostructure photocatalyst shows a superior photocatalytic activity. • Based on Mott-Schottky analysis and active species detection, a mechanism for the separation of photogenerated carriers is proposed. • The effective separation process of the photogenerated electron-hole pairs was testified by photocurrent test. - Abstract: In{sub 2}O{sub 3}/Bi{sub 2}Sn{sub 2}O{sub 7} composite photocatalysts with various contents of cubic In{sub 2}O{sub 3} nanoparticles were fabricated by using impregnation method. A thriving modification of Bi{sub 2}Sn{sub 2}O{sub 7} by an introduction of In{sub 2}O{sub 3} was confirmed by using X-ray diffraction, UV–vis diffuse reflectance spectrometry, transmission electron microscopy, high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy. The samples composed of hybrids of In{sub 2}O{sub 3} and Bi{sub 2}Sn{sub 2}O{sub 7} exhibited a much higher photocatalytic activity for the degradation of Rhodamine B under visible light, as compared with pure In{sub 2}O{sub 3} and Bi{sub 2}Sn{sub 2}O{sub 7} nanoparticles. Optimized composition of the composite photocatalysts was 0.1In{sub 2}O{sub 3}/Bi{sub 2}Sn{sub 2}O{sub 7}, which shows a rate constant higher than those of pure In{sub 2}O{sub 3} and Bi{sub 2}Sn{sub 2}O{sub 7} by 4.06 and 3.21 times, respectively. Based on Mott-Schottky analysis and active species detection, the photoexcited electrons in the conduction band of In{sub 2}O{sub 3} and the holes in the valence band of Bi{sub 2}Sn{sub 2}O{sub 7} participated in reduction and oxidation reactions, respectively. Hence, ·OH, ·O{sub 2}{sup −} and h
Structure and crystallization of B{sub 2}O{sub 3}-Al{sub 2}O{sub 3}-SiO{sub 2} glasses

Energy Technology Data Exchange (ETDEWEB)

Cheng Yin, E-mail: zjbcy@126.co [College of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410114 (China); Xiao Hanning [College of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410114 (China); College of Materials Science and Engineering, Hunan University, Changsha 410082 (China); Shuguang Chen; Tang Bingzhong [College of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410114 (China)

2009-05-01

B{sub 2}O{sub 3}-Al{sub 2}O{sub 3}-SiO{sub 2} glasses with different B{sub 2}O{sub 3}/Al{sub 2}O{sub 3} ratios of 0.4-1.3 were prepared by the melting-quenching method at 1500-1600 deg. C for 2 h. Fragility index F was used to estimate the glass-forming ability. The infrared (IR) absorption curves and differential scanning calorimetry (DSC) curves of the glasses have been investigated for estimating the influence of the B{sub 2}O{sub 3}/Al{sub 2}O{sub 3} ratio on glass structure and crystallization of the B{sub 2}O{sub 3}-Al{sub 2}O{sub 3}-SiO{sub 2} glass system. The crystallization kinetics of the glasses were described by activation energy (E) for crystallization and calculated by the Kissinger method. X-ray diffraction (XRD) and SEM analyses were also used to describe the types and morphologies of the crystals precipitated from the B{sub 2}O{sub 3}-Al{sub 2}O{sub 3}-SiO{sub 2} glasses. The results show that with the increase of B{sub 2}O{sub 3}/Al{sub 2}O{sub 3} ratio, glass stability improves and the trend of crystallization decreases relatively. However, when the B{sub 2}O{sub 3}/Al{sub 2}O{sub 3} ratio reaches 1.3, boron-abnormal phenomenon appears and results in the raising trend of crystallization. Rod-like crystals of Al{sub 4}B{sub 2}O{sub 9} and Al{sub 20}B{sub 4}O{sub 36} were observed in the crystallized samples.
Zero photoelastic and water durable ZnO–SnO–P{sub 2}O{sub 5}–B{sub 2}O{sub 3} glasses

Energy Technology Data Exchange (ETDEWEB)

Saitoh, Akira; Nakata, Kohei; Yamamoto, Naoki; Takebe, Hiromichi [Graduate School of Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama 790-8577 (Japan); Tricot, Grégory; Chen, Yuanyuan [LASIR UMR-CNRS 8516, Université de Lille 1, Villeneuve d’Ascq F-59655 (France)

2015-04-01

We report properties of zero birefringent xZnO–(67–x)SnO–(33–y)P{sub 2}O{sub 5}–y B{sub 2}O{sub 3} glasses, within 18.5 ≤ x ≤ 22 and y = 0, 3, and 10 mol. %. These compositions of boro-phosphate glasses provide both zero photoelastic constant (PEC) and improved water durability. x = 19 and y = 3 compositions show minimum PEC of −0.002 × 10{sup −12} Pa{sup −1}, which can contribute to candidate material for fiber current sensor devise without lead. The structures of zero photoelastic glasses were investigated by Raman scattering and nuclear magnetic resonance spectroscopies. Compositions of zero PEC glasses are explained by the empirical model proposed by Zwanziger et al. [Chem. Mater. 19, 286-290 (2007)].
3-D MnNb{sub 2}O{sub 6} nanogears from 1-D Nb{sub 2}O{sub 5} nanorods

Energy Technology Data Exchange (ETDEWEB)

Hu Weibing, E-mail: w.hu@tom.com [School of Chemical and Environmental Engineering, Hubei Institute for Nationalities, Enshi 445000 (China); Cui Zhicai [School of Chemical and Environmental Engineering, Hubei Institute for Nationalities, Enshi 445000 (China); Mi Yuanzhu [School of Chemistry and Environmental Engineering, Yangtze University, Nanhuan Road 1, Jingzhou 434023 (China)

2012-04-16

Graphical abstract: The geometry morphology of Nb-based nanomaterial evolved from long Nb{sub 2}O{sub 5} nanorods to a mixture of short Nb{sub 2}O{sub 5} nanorods and MnNb{sub 2}O{sub 6} 6-teeth nanogears, and eventually to fully developed pure 3-D nanogears. Highlights: Black-Right-Pointing-Pointer MnNb{sub 2}O{sub 6} nanogears have been generated by a simple solvothermal process when the Mn: Nb ratio was 1:1. Black-Right-Pointing-Pointer MnNb{sub 2}O{sub 6} 6-teeth nanogears accompanied with MnNb{sub 2}O{sub 6} 5-teeth nanogears are got when the Mn:Nb ratio reached 1:2. Black-Right-Pointing-Pointer The nanomaterial consists of nanorods and 6-teeth nanogears at low Mn:Nb molar ratio(1:4). Black-Right-Pointing-Pointer Pure long Nb{sub 2}O{sub 5} nanorods are achieved by only using NbCl{sub 5} - Abstract: MnNb{sub 2}O{sub 6} nanogears have been generated by using mixed NbCl{sub 5} and MnCl{sub 2} at an optimized ratio of 1:1 in a cyclohexanol solvent in a simple solvothermal process. It has shown that the Mn:Nb ratio determines the shape of the products. Detailed characterization by electron microscopy has shown that increasing the Mn{sup +2} concentration during the solvo-thermal synthesis promotes a morphological evolution from relatively long Nb{sub 2}O{sub 5} nanorods to a mixture of short Nb{sub 2}O{sub 5} nanorods and MnNb{sub 2}O{sub 6} 6-teeth nanogears, then to a mixture of short Nb{sub 2}O{sub 5} nanorods and more MnNb{sub 2}O{sub 6} 6-teeth nanogears, then to more and more MnNb{sub 2}O{sub 6} 6-teeth nanogears that are occasionally accompanied with under-developed MnNb{sub 2}O{sub 6} 5-teeth nanogears, and eventually to fully developed pure 3-D nanogears. The driving force for such interesting geometry transformations is attributed to the inclusion of Mn{sup 2+} into the Nb{sub 2}O{sub 5} template at low Mn{sup 2+} concentrations, which introduces internal stresses to the Nb{sub 2}O{sub 5} nanorods. At high Mn{sup 2+} concentrations, close to the
Study of groundwater in the Chicu River basin, Sabana de Bogota, Colombia; Estudio de las aguas subterraneas de la cuenca del Rio Chicu, Sabana de Bogota, Colombia

Energy Technology Data Exchange (ETDEWEB)

Obando G, E; Jimenez B, G; Torres Q, E; Alayon C, E; Garavito B, F [Instituto de Ciencias Nucleares y Energias Alternativas, INEA, Bogota (Colombia)

1995-10-01

The Rio Chicu Valley aquifer system represents one of the many sub-systems constituting the hydrogeological system of the Sabana de Bogota. The valley has a structure of a graben, covered by a quaternary alluvial formation, which has a low permeability and therefore is an aquifer of poor characteristics. Due to the thickness of this aquifer (around 300 m), the tertiary aquifers are only exploited by few deep wells. The isotopic composition of water collected from the tertiary aquifer is depleted by 1 per mille in {delta}{sup 18}O and 8 per mille in {delta}D. This difference is due to the altitude effect of recharge, because the tertiary aquifers outcrop on the top of the surrounding hills. In some places, the stable isotope content of water sampled in wells tapping water from the quaternary aquifer is similar to the values found in the tertiary aquifer. This fact indicates the ascending leakage from deep horizons. A rather unique characteristics of the quaternary aquifer is that in the central part of the basin the dissolved inorganic carbon DIC is very high and shows a {delta}{sup 13}C values around +10 per mille vs PDB and {sup 14}C around 5-10 pmc. The positive values are probably related to decomposition of organic matter in anaerobic conditions. These values reflect a very low flow in the system and limited recharge. (author). 1 ref., 5 figs, 2 tabs.

Palaeohydrological implications in the Baltic area and its relation to the groundwater at Aespoe, south-eastern Sweden - A literature study

Energy Technology Data Exchange (ETDEWEB)

Wallin, B [Geokema AB, Lidingoe (Sweden)

1995-03-01

A literature study of different groundwaters in the circum Baltic region is presented in this work. The study is mainly focused on the isotopic signatures observed in different groundwaters in Sweden and Finland. Several saline groundwaters in the Baltic region at depth of 150 to 500m depth show stable ({delta}D, {delta}{sup 13}C, {delta}{sup 18}O) and radiogenic ({delta}{sup 87}Sr) isotope assembly which is suggestive of a marine origin. However, a discrepancy is sometimes observed between the stable as well as radiogenic isotopes of the intermediate groundwater, which suggest a mixture of fossil marine water and a post-glacial runoff of melt water. In order to explain this phenomenon, the initial setting in {delta}{sup 18}O may have been depleted due to large input of high latitude marine water or cold melt waters. A solution to the contradiction between the strontium ({delta}{sup 87}Sr) and stable isotope ({delta}D, {delta}{sup 13}C, {delta}{sup 18}O) signatures of the groundwater and of the calcite fracture fillings at Aespoe and other places is attained, if it is assumed that the strontium in Baltic Sea water has undergone a significant decrease in {delta}{sup 87}Sr since the last glaciation. A scenario can be constructed to suggest that the Baltic Sea during the initial stage of the Litorina sea (8000 to 5000 Y B.P.) contained strontium with much larger {delta}{sup 87}Sr values. Another explanation for the positive {delta}{sup 87}Sr values may be due to water/rock interaction between the groundwater and the abundant fracture clay minerals, which are observed at Aespoe. Typically most of the saline groundwaters occur both in Sweden and Finland below the highest marine shore line during the Holocene. Almost all inland groundwaters show a totally different pattern which is typically non marine, meteoric in origin. (Abstract Truncated)
Effect of ageing on optical and thermal properties of YBa{sub 2}Cu{sub 3}O{sub 7}-{delta}

Energy Technology Data Exchange (ETDEWEB)

Nikolic, P.M.; Vujatovic, S.S.; Savic, S.M.; Ristic, M.M. [Institute of Technical Sciences of SASA, Belgrade (Czechoslovakia); Paraskevopoulos, K.M.; Zorbas, K.T. [Aristotle Univ., Thessaloniki (Greece). Solid State Section; Nikolic, M.V.; Aleksic, O.S. [Belgrade Univ. (Czechoslovakia). Center for Multidisciplinary Studies

2007-07-15

Photoacoustic phase and amplitude spectra of YBa{sub 2}Cu{sub 3}O{sub 7}-{delta} samples synthesised 18 years ago were measured and numerically analysed. The value of thermal diffusivity obtained on the aged samples was lower than the values obtained for fresh samples. Far infrared spectra of YBa{sub 2}Cu{sub 3}O{sub 7}-{delta} samples synthesised 18 years ago were recorded and analysed enabling determination of reflectivity peak phonon frequencies present at room temperature. X-ray diffraction analysis and far infrared reflectivity measurements enabled determination of a slight change of the oxygen content with time. The YBa{sub 2}Cu{sub 3}O{sub 7}-{delta} samples synthesised 18 years ago still remained superconducting, which was confirmed by resistivity measurements of the samples between 50 K and room temperature where the critical temperature was reduced from 93 to 73 K. Atomic force microscopy, scanning electron microscopy and energy dispersive X-ray microanalytical measurements were also performed confirming the composition of the sample. (orig.)
Structural, magnetic, electrical and electrochemical properties of NiFe{sub 2}O{sub 4} synthesized by the molten salt technique

Energy Technology Data Exchange (ETDEWEB)

Senthilkumar, Baskaran [Solid State Ionics and Energy Devices Laboratory, Department of Physics, Bharathiar University, Coimbatore 641 046 (India); Kalai Selvan, Ramakrishnan, E-mail: selvankram@buc.edu.in [Solid State Ionics and Energy Devices Laboratory, Department of Physics, Bharathiar University, Coimbatore 641 046 (India); Vinothbabu, Palanisamy [Department of Physics, Gobi Arts and Science College, Gobichettipalayam 638 453 (India); Perelshtein, Ilana [Kanbar Laboratory for Nanomaterials, Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900 (Israel); Gedanken, Aharon, E-mail: gedanken@mail.biu.ac.il [Kanbar Laboratory for Nanomaterials, Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900 (Israel)

2011-10-17

Highlights: {yields} The article describes the comprehensive study of molten salt synthesised NiFe{sub 2}O{sub 4}. {yields} The optimized NiFe{sub 2}O{sub 4} were further studied for their application as electrodes in redox supercapacitors and hydrogen evolving reaction (HER) using cyclic voltammetry (CV) and linear sweep voltammetry (LSV) techniques, respectively. {yields} The electrochemical characterization of NiFe{sub 2}O{sub 4} showed pseudocapacitive property and exhibited specific capacitance of 18.5 F g{sup -1}. {yields} It also confirmed through LSV, the prepared NiFe{sub 2}O{sub 4} has good electrocatalytic behavior compared with its individual constituents like NiO and Fe{sub 2}O{sub 3} as well as the NiFe{sub 2}O{sub 4} prepared by solid state reaction. - Abstract: Submicron-sized NiFe{sub 2}O{sub 4} particles were synthesized by the molten salt method at 900 deg. C using binary melts of a NaCl and KCl mixture that acts as a flux. The X-ray diffraction pattern confirmed the single phase, high crystalline and cubic structure of NiFe{sub 2}O{sub 4} with a Fd3m space group. The FT-IR spectra reveal the stretching vibration of octahedral complexes of Fe{sup 3+}-O{sup 2-} through the observed band around 552.3 cm{sup -1}. The SEM and TEM image had indicated the formation of submicron-sized NiFe{sub 2}O{sub 4} particles. The ferrimagnetic behavior and high saturation magnetization of 44 emu g{sup -1} was elucidated by VSM. The maximum electrical conductivity of 1.42 x 10{sup -4} S cm{sup -1} was observed at 873 K. The NiFe{sub 2}O{sub 4} showed a pseudocapacitive property in 1 M of a LiClO{sub 4} electrolyte and exhibited a specific capacitance of 18.5 F g{sup -1} at 10 mV s{sup -1}. The hydrogen evolution reaction was also studied for NiFe{sub 2}O{sub 4} in 1 M of a H{sub 2}SO{sub 4} solution.
Anti-bombing insensitivity life of molybdenum cathode doped with La{sub 2}O{sub 3} and Y{sub 2}O{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Wang Jinshu [School of Materials Science and Engineering, Beijing University of Technology, Beijing 100022 (China)]. E-mail: wangjsh@bjut.edu.cn; Wang Yiman [School of Materials Science and Engineering, Beijing University of Technology, Beijing 100022 (China); Zhou Meiling [School of Materials Science and Engineering, Beijing University of Technology, Beijing 100022 (China)

2006-03-15

Anti-bombing insensitivity of La{sub 2}O{sub 3}-Y{sub 2}O{sub 3}-Mo secondary emitter has been studied in this paper. The variation of maximum secondary emission coefficient {delta} {sub max} with time was measured. The cathode after life experiment was analyzed by means of HRM, SEM, EDS and XRD. The results showed that {delta} {sub max} of La{sub 2}O{sub 3}-Y{sub 2}O{sub 3}-Mo cathode operating at 1100 deg. C under continuous electron bombardment of 300 W/cm{sup 2} was still about 2.5 after 1000 h operation, indicating that this kind of cathode had good anti-bombing insensitivity. In the internal part of the cathode, RE{sub 2}O{sub 3} (rare earth oxide) and molybdenum grains distributed alternately and there existed a certain relationship between crystallographic orientation of RE{sub 2}O{sub 3} and that of molybdenum. It was found that a RE{sub 2}O{sub 3} layer was formed on the surface after operation. The high {delta} {sub max} of La{sub 2}O{sub 3}-Y{sub 2}O{sub 3}-Mo cathode was related to the RE{sub 2}O{sub 3} layer on the surface and the amount of nanosized La{sub 2}O{sub 3} particles on the Y{sub 2}O{sub 3} layer.
Magnetically separable mesoporous Fe{sub 3}O{sub 4}/silica catalysts with very low Fe{sub 3}O{sub 4} content

Energy Technology Data Exchange (ETDEWEB)

Grau-Atienza, A.; Serrano, E.; Linares, N. [Molecular Nanotechnology Laboratory, Department of Inorganic Chemistry, University of Alicante, Carretera San Vicente s/n, E-03690 Alicante (Spain); Svedlindh, P. [Department of Engineering Sciences, Uppsala University, Box 534, SE-75121 Uppsala (Sweden); Seisenbaeva, G., E-mail: Gulaim.Seisenbaeva@slu.se [Department of Chemistry and Biotechnology, BioCenter SLU, Box 7015, SE-75007 Uppsala (Sweden); García-Martínez, J., E-mail: j.garcia@ua.es [Molecular Nanotechnology Laboratory, Department of Inorganic Chemistry, University of Alicante, Carretera San Vicente s/n, E-03690 Alicante (Spain)

2016-05-15

Two magnetically separable Fe{sub 3}O{sub 4}/SiO{sub 2} (aerogel and MSU-X) composites with very low Fe{sub 3}O{sub 4} content (<1 wt%) have been successfully prepared at room temperature by co-condensation of MPTES-functionalized Fe{sub 3}O{sub 4} nanoparticles (NPs) with a silicon alkoxide. This procedure yields a homogeneous incorporation of the Fe{sub 3}O{sub 4} NPs on silica supports, leading to magnetic composites that can be easily recovered using an external magnetic field, despite their very low Fe{sub 3}O{sub 4} NPs content (ca. 1 wt%). These novel hybrid Fe{sub 3}O{sub 4}/SiO{sub 2} materials have been tested for the oxidation reaction of 3,3′,5,5′-tetramethylbenzidine (TMB) with hydrogen peroxide showing an enhancement of the stability of the NPs in the Fe{sub 3}O{sub 4}/silica aerogel as compared to the Fe{sub 3}O{sub 4} NPs alone, even after five catalytic cycles, no leaching or agglomeration of the Fe{sub 3}O{sub 4}/SiO{sub 2} systems. - Graphical abstract: Novel magnetically separable mesoporous silica-based composites with very low magnetite content. - Highlights: • An innovative way to prepare magnetically separable composites with <1 wt% NPs. • The Fe{sub 3}O{sub 4}/silica composites are readily magnetized/demagnetized. • The Fe{sub 3}O{sub 4}/silica composites can be easily recovered using an external magnetic field. • Excellent catalytic performance and recyclability despite the low Fe{sub 3}O{sub 4} NPs content.
Characterisation of a tertiary mixture of {alpha}-Fe{sub 2}O{sub 3}, {gamma}-Fe{sub 2}O{sub 3} and Fe{sub 3}O{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Srinivasan, M.P.; Narasimhan, S.V. [Water and Steam Chemistry Laboratory (Chemistry Group, BARC) BARC Facilities, Kalpakkam, Tamil Nadu 603 102. (India)

1998-12-31

A method has been developed to quantify the individual components of a ternary mixture containing {alpha}-Fe{sub 2}O{sub 3}, {gamma}- Fe{sub 2}O{sub 3} and Fe{sub 3}O{sub 4} based on the preferential dissolution of the components at a fixed time (fixed time - depending on the strength of the chelating agent) in a dilute chemical formulation (containing a chelant and an organic acid) both in presence and absence of reductant. A ternary component diagram was constructed based on the percentage dissolution of the individual components in 2,6-Pyridine dicarboxylic acid (PDCA), Nitrilo triacetic acid (NTA) and EDTA based formulation at 60degC both in presence and absence of reductant. In these formulations, the observed behaviour that the {alpha}-Fe{sub 2}O{sub 3} dissolved very little both in presence and absence of reductant and {gamma}-Fe{sub 2}O{sub 3} dissolved very little in absence of reductant were used for resolving the ternary physical mixture composition. Physical mixtures of Fe{sub 3}O{sub 4}, {alpha}-Fe{sub 2}O{sub 3} and {gamma}-Fe{sub 2}O{sub 3} based on mole ratio were taken such that the total quantity of Fe present would be 1.37 mM for complete dissolution. In presence and absence of reductant, dissolution percentage of Fe observed at fixed time in these formulations, when fit into the already constructed three component phase diagram for each formulation at the same fixed duration, the experimentally resolved composition showed good agreement with that based on individual components. This method is useful to resolve different polymorphs of metal oxides having the metal ions in single and/or multiple oxidation states. (author)
Simultaneous Measurement of Nitrogen and Oxygen Isotopes of Nitrate to Evaluate Nitrate Sources and Processes in Catchments

Energy Technology Data Exchange (ETDEWEB)

Ohte, Nobuhito [Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo (Japan); Nagata, Toshi; Tayasu, Ichiro [Center for Ecological Research, Kyoto University, Ohtsu (Japan); Kyozu, Ayato; Yoshimizu, Chikage [CREST, Japan Science and Technology Agency, Center for Ecological Research, Kyoto University, Ohtsu (Japan); Osaka, Ken' ichi [Carbon and Nutrient Cycles Division, National Institute for Agro-Environmental Sciences, Tsukuba, (Japan)

2013-05-15

We review studies on applied isotope analytical techniques for identifying sources and transformations of river nitrate (NO{sub 3}{sup -}) to examine the influences of water pollution, excess nutrient (nitrogen) loads and ecosystem disturbances in river systems. We also discuss the current status and future perspectives of the application of NO{sub 3}{sup -} isotope measurements to the assessment of river nutrients. Our review shows that in recent years simultaneous measurements of nitrogen and oxygen isotopes ({delta}{sup 15}N and {delta}{sup 18}O) of NO{sub 3}{sup -} have been increasingly used to identify the sources and pathways of nitrogen in river systems. The {delta}{sup 15}N value of NO{sub 3}{sup -} is a useful indicator to evaluate the contributions of sewage and/or animal waste to NO{sub 3}{sup -} load, and the {delta}{sup 18}O value can be used for estimation of the contribution of NO{sub 3}{sup -} derived through atmospheric deposition. The microbial denitrification method is currently a most useful tool to measure the {delta}{sup 15}N and {delta}{sup 18}O values of NO{sub 3}{sup -} simultaneously, because of its capability for high throughput of samples. This method allows us to conduct a comprehensive investigation of spatial and temporal variations and mechanisms of nitrogen transport and transformation in rivers and catchments in more precise and effective manner. (author)
PDB2Graph: A toolbox for identifying critical amino acids map in proteins based on graph theory.

Science.gov (United States)

Niknam, Niloofar; Khakzad, Hamed; Arab, Seyed Shahriar; Naderi-Manesh, Hossein

2016-05-01

The integrative and cooperative nature of protein structure involves the assessment of topological and global features of constituent parts. Network concept takes complete advantage of both of these properties in the analysis concomitantly. High compatibility to structural concepts or physicochemical properties in addition to exploiting a remarkable simplification in the system has made network an ideal tool to explore biological systems. There are numerous examples in which different protein structural and functional characteristics have been clarified by the network approach. Here, we present an interactive and user-friendly Matlab-based toolbox, PDB2Graph, devoted to protein structure network construction, visualization, and analysis. Moreover, PDB2Graph is an appropriate tool for identifying critical nodes involved in protein structural robustness and function based on centrality indices. It maps critical amino acids in protein networks and can greatly aid structural biologists in selecting proper amino acid candidates for manipulating protein structures in a more reasonable and rational manner. To introduce the capability and efficiency of PDB2Graph in detail, the structural modification of Calmodulin through allosteric binding of Ca(2+) is considered. In addition, a mutational analysis for three well-identified model proteins including Phage T4 lysozyme, Barnase and Ribonuclease HI, was performed to inspect the influence of mutating important central residues on protein activity. Copyright © 2016 Elsevier Ltd. All rights reserved.
Ozone exposure induces the activation of leaf senescence-related processes and morphological and growth changes in seedlings of Mediterranean tree species

Energy Technology Data Exchange (ETDEWEB)

Ribas, Angela [CSIC-CEAB-CREAF Ecophysiology Unit, CREAF-Center for Ecological Research and Forestry Applications, Edifici C, Universitat Autonoma de Barcelona, 08193 Bellaterra, Barcelona (Spain)]. E-mail: a.ribas@creaf.uab.es; Pen-tilde uelas, Josep [CSIC-CEAB-CREAF Ecophysiology Unit, CREAF-Center for Ecological Research and Forestry Applications, Edifici C, Universitat Autonoma de Barcelona, 08193 Bellaterra, Barcelona (Spain)]. E-mail: josep.penuelas@uab.es; Elvira, Susana [CIEMAT, Avd. Complutense 22, 28040 Madrid (Spain); Gimeno, Benjamin S. [CIEMAT, Avd. Complutense 22, 28040 Madrid (Spain)

2005-03-01

Four Mediterranean tree taxa, Quercus ilex subsp. ilex, Quercus ilex subsp. ballota, Olea europaea cv. vulgaris and Ceratonia siliqua, were exposed to different ozone (O{sub 3}) concentrations in open top chambers (OTCs) during 2 years. Three treatments were applied: charcoal-filtered air (CF), non-filtered air (NF) and non-filtered air plus 40 ppb{sub v} of O{sub 3} (NF+). The photochemical maximal efficiency, Fv/Fm, decreased in NF+ plants during the second year of exposure, especially during the most stressful Mediterranean seasons (winter and summer). An increase of {delta}{sup 13}C was found in three of the four studied species during the first year of exposure. This finding was only maintained in C. siliqua during the second year. Decreases in the chlorophyll content were detected during the first year of fumigations in all the species studied, but not during the second year. The NF+ treatment induced changes in foliar anatomical characteristics, especially in leaf mass per area (LMA) and spongy parenchyma thickness, which increased in some species. A reduction in N content and an increase in {delta}{sup 15}N were found in all species during the second year when exposed in the NF+ OTCs, suggesting a change in their retranslocation pattern linked to an acceleration of leaf senescence, as also indicated by the above mentioned biochemical and anatomical foliar changes. The two Q. ilex subspecies were the most sensitive species since the changes in N concentration, {delta}{sup 15}N, chlorophyll, leaf area, LMA and biomass occurred at ambient O{sub 3} concentrations. However, C. siliqua was the most responsive species (29% biomass reduction) when exposed to the NF+ treatment, followed by the two Q. ilex subspecies (14-20%) and O. europaea (no significant reduction). Ozone resistance of the latter species was linked to some plant traits such as chlorophyll concentrations, or spongy parenchyma thickness. - Ozone induces species-specific leaf senescence
Polyaniline as a cathode for O/sub 2/ reduction - kinetics of the reaction with H/sub 2/O/sub 2/ and use of the polymer in a model H/sub 2/O/sub 2/ fuel cell

Energy Technology Data Exchange (ETDEWEB)

Doubova, L.; Mengoli, G.; Musiani, M.M.; Valcher, S.

1989-03-01

Oxygen reduction at a polyaniline cathode occurs in aqueous sulfuric acid through a chemical-electrochemical route which involves the intermediate oxidation of leucoemeraldine to emeraldine with the formation of H/sub 2/O/sub 2/. This paper specifically deals with the conversion of leucoemeraldine to emeraldine by H/sub 2/O/sub 2/ whose kinetics, apparently second order on the charge exchange, are similar to those found for the reaction with O/sub 2/, although they occur at lower rate. The catalytic four electron O/sub 2/ reduction mediated by the Fe(III)/Fe(II) couple which decomposes H/sub 2/O/sub 2/ is not fully achieved. However, polyaniline proved to be a reliable cathode for O/sub 2/, sustaining the working of a model H/sub 2//O/sub 2/ fuel cell.
Microbial O{sub 2} consumption in the Aespoe tunnel

Energy Technology Data Exchange (ETDEWEB)

Kotelnikova, S.; Pedersen, Karsten [Goeteborg Univ. (Sweden). Dept. of Cell and Molecular Biology, Microbiology

1998-04-01

The report presents data on microbial O{sub 2} reduction activities by microorganisms obtained with different techniques: Winkler method, gas chromatography, most probable numbering, enrichment technique, inhibitor analysis and radiotracer measurements. The samples were collected from boreholes and open funnel ponds at Aespoe in 1996-1998. The evaluation of the microbial activities in open ponds predicts the future microbial activities after the O{sub 2} intrusion around the future repository. The metabolic potential of the microbial population inhabiting groundwater was evaluated on the basis of electron donors available and microbial 16S rRNA gene diversity. The contribution of different microbial groups to the O{sub 2} reduction was elucidated using specific inhibitors selectively affecting different microbial groups. Our experiments show that microbial O{sub 2} reduction occurs in deep groundwater. Carbon dioxide was produced concurrently with O{sub 2} reduction confirming the biogenic nature of the reduction. The populations developed O{sub 2} reduction rates and capacity depending on the initial concentration of dissolved O{sub 2} reduction. Rates of O{sub 2} reduction ranged from 0.32 to 4.5 {mu}M/day. Depending on temperature and the type of groundwater the approximate time needed for consumption of 500 {mu}M of dissolved O{sub 2} ranged from 0.31 to 3.99 years. After approximately a 2 weeks period the microbial population in vitro was able to consume O{sub 2} both at 30 deg C and 60 deg C. At 16 deg C no delay in O{sub 2} consumption was observed. Our results demonstrated that methanotrophs survive in deep groundwater and that they were induced by O{sub 2}. Some bacteria use Hg or CH{sub 4} as electron donor instead of organic matter, which means that microbial O{sub 2} reduction will occur also in deep groundwaters where the availability of organic carbon is limited. Specific CH{sub 4} oxidation rates ranged between 3.00 and 220 nM CH{sub 4} per litre per
Stable Isotopes in Precipitation over Indonesia Maritime Continent

Energy Technology Data Exchange (ETDEWEB)

Ichiyanagi, K. [Graduate School of Science and Technology, Kumamoto University, and Japan Agency for Marine-Earth Science and Technology (JAMSTEC) (Japan); Suwarman, R. [Graduate School of Science and Technology, Kumamoto University (Japan); Yamanaka, M. D. [Japan Agency for Marine-Earth Science and Technology (JAMSTEC) (Japan)

2013-07-15

Daily variability of stable isotopes in precipitation was observed at 6 stations in the Indonesian Maritime Continent from 2000 to 2006. The annual mean {delta}{sup 18}O at Bukit Kototabang (GAW), Jambi, and Makassar are heavier than those for others. The precipitation amount effect was observed only at Denpasar and Makassar. There are 2 groups resulting from the local Meteoric Water line; (1) slope is nearly 7.0 and high d-excess more than 10 at GAW, Denpasar, and Manado, (2) slope is around 7.4 and low d-excess less than 7.5 per mille at Jambi, Makassar, and Palau. Seasonal variability of {delta}{sup 18}O and d-excess were classified into three patterns. There are no seasonal variations in {delta}{sup 18}O and d-excess at GAW and Jambi, but clear seasonal variations at Denpasar (DPS) and Makassar (MKS). Due to the amount effect, {delta}{sup 18}O in precipitation is high when the precipitation amount is low from May to october. In contrast, the amount effect is not significant and d-excess is constant throughout the year in Manado and Palau. The {delta}{sup 18}O in precipitation at 2 stations located in sumatra Island corresponded with the Madden-Jullian Oscillation index, while those for the other 4 stations in more easterly locations did not. This finding indicates that water vapour evaporated from the Indian Ocean can reach the Island of sumatra, but can't reach more easterly locations. (author)
Enhanced surface transfer doping of diamond by V{sub 2}O{sub 5} with improved thermal stability

Energy Technology Data Exchange (ETDEWEB)

Crawford, Kevin G., E-mail: k.crawford.2@research.gla.ac.uk; Moran, David A. J. [School of Engineering, University of Glasgow, Glasgow G12 8LT (United Kingdom); Cao, Liang [High Magnetic Field Laboratory, Chinese Academy of Sciences, 350 Shushanhu Road, Hefei 230031, Anhui (China); Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, Singapore 117542 (Singapore); Qi, Dongchen, E-mail: d.qi@latrobe.edu.au [Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086 (Australia); Tallaire, Alexandre [LSPM-CNRS, Université Paris 13, Villetaneuse 93430 (France); Limiti, E.; Verona, C. [Department of Industrial Engineering, “Tor Vergata” University, Rome 00173 (Italy); Wee, Andrew T. S. [Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, Singapore 117542 (Singapore)

2016-01-25

Surface transfer doping of hydrogen-terminated diamond has been achieved utilising V{sub 2}O{sub 5} as a surface electron accepting material. Contact between the oxide and diamond surface promotes the transfer of electrons from the diamond into the V{sub 2}O{sub 5} as revealed by the synchrotron-based high resolution photoemission spectroscopy. Electrical characterization by Hall measurement performed before and after V{sub 2}O{sub 5} deposition shows an increase in hole carrier concentration in the diamond from 3.0 × 10{sup 12} to 1.8 × 10{sup 13 }cm{sup −2} at room temperature. High temperature Hall measurements performed up to 300 °C in atmosphere reveal greatly enhanced thermal stability of the hole channel produced using V{sub 2}O{sub 5} in comparison with an air-induced surface conduction channel. Transfer doping of hydrogen-terminated diamond using high electron affinity oxides such as V{sub 2}O{sub 5} is a promising approach for achieving thermally stable, high performance diamond based devices in comparison with air-induced surface transfer doping.
Activity of RE/sub 2/O/sub 3/ in liquid La/sub 2/O/sub 3/-Al/sub 2/O/sub 3/-CaF/sub 2/ and Ce/sub 2/O/sub 3/-CaO-CaF/sub 2/ slags

International Nuclear Information System (INIS)

Changzhen, W.; Shuqing, Y.; Qieng, D.

1985-01-01

In the course of electro-slag refining, if the slag contains rare earth oxides, the amount of rare earth introduced to the steel depends on the composition of the slag and other conditions. The main aim of this investigation is to study the activity of RE/sub 2/O/sub 3/ in the electro-slags of various compositions. One is the La/sub 2/O/sub 3/-CaO-CaF/sub 2/ ternary slag system and the other is the Ce/sub 2/O/sub 3/-CaO-CaF/sub 2/ slag system. The iso-activity diagram for RE/sub 2/O/sub 3/ and the liquid boundary for slags system were estimated
Preparation and characterization of Nb{sub 2}O{sub 5}-Al{sub 2}O{sub 3} composite oxide formed by cathodic electroplating and anodizing

Energy Technology Data Exchange (ETDEWEB)

Jang, Joo-Hee; Kim, Tae-Yoo; Kim, Nam-Jeong; Lee, Chang-Hyoung; Park, Eun-Mi [School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Park, Chan [Division of Materials Science and Engineering, Pukyong National University, Busan 608-739 (Korea, Republic of); Suh, Su-Jeong, E-mail: suhsj@skku.ac.kr [School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Advanced Materials and Process Research Center for IT, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

2011-11-15

Highlights: > We fabricate Nb{sub 2}O{sub 5}-Al{sub 2}O{sub 3}/Al film for high performance thin film capacitor. > The optimum condition of electrolyte composition will coat NbO{sub x} on Al without corrosion of Al during the cathodic electroplating. > Increasing annealing temperature will form Nb{sub 2}O{sub 5} crystalline. > The Al{sub 2}O{sub 3} layer will form between Nb{sub 2}O{sub 5} layer and metal Al after anodizing and the thin film capacitor with Nb{sub 2}O{sub 5}-Al{sub 2}O{sub 3}/Al improve dielectric properties. - Abstract: Al foil was coated with niobium oxide by cathodic electroplating and anodized in a neutral boric acid solution to achieve high capacitance in a thin film capacitor. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) revealed the niobium oxide layer on Al to be a hydroxide-rich amorphous phase. The film was crystalline and had stoichiometric stability after annealing at temperatures up to 600 deg. C followed by anodizing at 500 V, and the specific capacitance of the Nb{sub 2}O{sub 5}-Al{sub 2}O{sub 3} composite oxide was approximately 27% higher than that of Al{sub 2}O{sub 3} without a Nb{sub 2}O{sub 5} layer. The capacitance was quite stable to the resonance frequency. Overall, the Nb{sub 2}O{sub 5}-Al{sub 2}O{sub 3} composite oxide film is a suitable material for thin film capacitors.
Light scattering by SiOsub(x) and TiOsub(x) films

Energy Technology Data Exchange (ETDEWEB)

Biedermann, A; Hacker, E; Schirmer, G; Walther, H G

1981-11-20

The scattering intensities of vapour-deposited SiOsub(x) films (x approx. <= 2) are the other of 10/sup -4/ if the incidence intensity is unity. This is of the same order of magnitude as the scattering intensity from highly polished optical glass surfaces. The low level of scattering results from the nearly amorphous film structure. Reactively evaporated TiOsub(x) films also exhibit a very low scattering intensity, whereas for reactively sputtered TiO/sub 2/ films the scattering intensity is strongly dependent on the partial pressure of oxygen in the sputtering gas. For films sputtered in 100% O/sub 2/ the scattering level amounts to a few per cent. This is due to the large grain sizes of up to 1 ..mu..m in these films. For low plasma oxygen concentrations TiO/sub 2/ films sputtered under unbiased conditions show microcrystalline sturctures of the anatase modification. However, when the oxygen partial pressure is increased and a bias voltage is applied to the substrate the rutile modification is produced.
Densification and mechanical properties of sintered Al{sub 2}O{sub 3}-Y{sub 3}Al{sub 5}O{sub 12} ceramic composite

Energy Technology Data Exchange (ETDEWEB)

Paneto, Flavio Jose; Pereira, Joaquim Lopes; Oliveira, Jean de Lima; Jesus Filho, Edson de; Silva, Leandro Anselmo da; Cabral, Ricardo de Freitas; Santos, Claudinei dos [Centro Universitario de Volta Redonda (UNIFOA), Volta Redonda, RJ (Brazil); Lima, Eduardo de Sousa [Institutlo Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil)

2014-06-15

In this work, Al{sub 2}O{sub 3}-Y{sub 3}Al{sub 5}O{sub 12} ceramic composites were developed with different proportions of Al{sub 2}O{sub 3}-Y{sub 3}Al{sub 5}O{sub 12}, which were mixed and compacted at different pressures of 40MPa to 100MPa, being consequently sintered at 1600 deg C-2h. The sintered samples were characterized by X-ray diffraction presenting α-Al{sub 2}O{sub 3} and Y{sub 3}Al{sub 5}O{sub 12} as crystalline phases. Samples with relative densities ranging from 78 to 80% and 87 to 91% were obtained depending on the composition and the compaction pressure used. The hardness values obtained were of 1010 to 1080HV and 370- 470HV, for mixes Al{sub 2}O{sub 3}-Y{sub 3}Al{sub 5}O{sub 12} having the composition with levels of 20 and 36.5wt.%, respectively. (author)
Correlation Between Electrical Conductivity and Catalytic Property in 78V{sub 2}O{sub 5}–15P{sub 2}O{sub 5}–7B{sub 2}O{sub 3} Glass Containing Fe{sub 2}O{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Jeong, Hwa-Jin; Kim, Jong-hwan; Ryu, Bong-Ki [Pusan National University, Busan (Korea, Republic of)

2016-12-15

In this study, we established a correlation between the electrical conductivity and catalytic properties of vanadium borophosphate glass containing Fe{sub 2}O{sub 3}. Glasses were synthesized in the 78V{sub 2}O{sub 5}–15P{sub 2}O{sub 5}–7B{sub 2}O{sub 3} ternary-system containing x mol% Fe{sub 2}O{sub 3} (x = 1, 5, 7.5, and 10). Electrical conductivity was measured at 45 ℃ for samples heat-treated at 340 ℃ for 12 h. To examine catalytic effects, we used TGA measurements of a mixture of fatty acid and sample powders. Fourier transform infrared spectroscopy (FTIR) was used to analyze the structural changes after crystallization, while X-ray photoelectron spectroscopy (XPS) analysis indicated changes with different valence state ions. X-ray diffraction (XRD) analysis of the structure array verified these inferred changes. Conductivity and catalytic effects are discussed in relation to the migration of vanadate ions and iron ions with different valence states due to the increase crystallinity.
Lattice dynamics of ZnAl{sub 2}O{sub 4} and ZnGa{sub 2}O{sub 4} under high pressure

Energy Technology Data Exchange (ETDEWEB)

Lopez-Moreno, S.; Rodriguez-Hernandez, P.; Munoz, A. [Departamento de Fisica Fundamental II, MALTA Consolider Team, Instituto de Materiales y Nanotecnologia Universidad de La Laguna, La Laguna 38205, Tenerife (Spain); Romero, A.H. [CINVESTAV-Queretaro Libramiento Norponiente No 2000 Real de Juriquilla 76230 Queretaro, Qro (Mexico); Manjon, F.J. [Instituto de Diseno para la Fabricacion y Produccion Automatizada, MALTA Consolider Team, Universitat Politecnica de Valencia, 46022 Valencia (Spain); Errandonea, D. [Fundacion General de la Universidad de Valencia ICMUV, MALTA Consolider Team, Edificio de Investigacion, C/Dr. Moliner 50, Burjassot, 46100 Valencia (Spain); Rusu, E.; Ursaki, V.V. [Institute of Applied Physics, Academy of Sciences of Moldova, 2028 Chisinau (Moldova)

2011-01-15

In this work we present a first-principles density functional study of the vibrational properties of ZnAl{sub 2}O{sub 4} and ZnGa{sub 2}O{sub 4} as function of hydrostatic pressure. Based on our previous structural characterization of these two compounds under pressure, herewith, we report the pressure dependence on both systems of the vibrational modes for the cubic spinel structure, for the CaFe{sub 2}O{sub 4}-type structure (Pnma) in ZnAl{sub 2}O{sub 4} and for marokite (Pbcm) ZnGa{sub 2}O{sub 4}. Additionally we report a second order phase transition in ZnGa{sub 2}O{sub 4} from the marokite towards the CaTi{sub 2}O{sub 4}-type structure (Cmcm), for which we also calculate the pressure dependence of the vibrational modes at the {gamma} point. Our calculations are complemented with Raman scattering measurements up to 12 GPa that show a good overall agreement between our calculated and measured mode frequencies. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Continuous mutual improvement of macromolecular structure models in the PDB and of X-ray crystallographic software: the dual role of deposited experimental data.

Science.gov (United States)

Terwilliger, Thomas C; Bricogne, Gerard

2014-10-01

Accurate crystal structures of macromolecules are of high importance in the biological and biomedical fields. Models of crystal structures in the Protein Data Bank (PDB) are in general of very high quality as deposited. However, methods for obtaining the best model of a macromolecular structure from a given set of experimental X-ray data continue to progress at a rapid pace, making it possible to improve most PDB entries after their deposition by re-analyzing the original deposited data with more recent software. This possibility represents a very significant departure from the situation that prevailed when the PDB was created, when it was envisioned as a cumulative repository of static contents. A radical paradigm shift for the PDB is therefore proposed, away from the static archive model towards a much more dynamic body of continuously improving results in symbiosis with continuously improving methods and software. These simultaneous improvements in methods and final results are made possible by the current deposition of processed crystallographic data (structure-factor amplitudes) and will be supported further by the deposition of raw data (diffraction images). It is argued that it is both desirable and feasible to carry out small-scale and large-scale efforts to make this paradigm shift a reality. Small-scale efforts would focus on optimizing structures that are of interest to specific investigators. Large-scale efforts would undertake a systematic re-optimization of all of the structures in the PDB, or alternatively the redetermination of groups of structures that are either related to or focused on specific questions. All of the resulting structures should be made generally available, along with the precursor entries, with various views of the structures being made available depending on the types of questions that users are interested in answering.

Facile preparation and enhanced microwave absorption properties of flake carbonyl iron/Fe{sub 3}O{sub 4} composite

Energy Technology Data Exchange (ETDEWEB)

Min, Dandan, E-mail: mdd4776@126.com; Zhou, Wancheng; Luo, Fa; Zhu, Dongmei

2017-08-01

Highlights: • Flake carbonyl iron/Fe{sub 3}O{sub 4} composites were prepared by surface oxidation technique. • Lower permittivity and modest permeability was obtained by the FCI/Fe{sub 3}O{sub 4} composites. • Enhanced absorption efficiency and broader absorption band were obtained. - Abstract: Flake carbonyl iron/Fe{sub 3}O{sub 4} (FCI/Fe{sub 3}O{sub 4}) composites with enhanced microwave absorption properties were prepared by a direct and flexible surface oxidation technique. The phase structures, morphology, magnetic properties, frequency-dependent electromagnetic and microwave absorption properties of the composites were investigated. The measurement results showed that lower permittivity as well as modest permeability was obtained by the FCI/Fe{sub 3}O{sub 4} composites. The calculated microwave absorption properties indicated that enhanced absorption efficiency and broader absorption band were obtained by the FCI/Fe{sub 3}O{sub 4} composite comparing with the FCI composite. The absorption frequency range with reflection loss (RL) below −5 dB of FCI/Fe{sub 3}O{sub 4} composites at reaction time of 90 min at thickness of 1.5 mm is 13.3 GHz from 4.7 to 18 GHz, while the bandwidth of the FCI composite is only 5.9 GHz from 2.6 to 8.5 GHz at the same thickness. Thus, such absorbers could act as effective and wide broadband microwave absorbers in the GHz range.
Role of O radical on the formation of O{sub 2} gas plasma; O{sub 2} purazuma ni okeru O rajikaru no yakuwari

Energy Technology Data Exchange (ETDEWEB)

Matsui, I. [Toshiba Reasearch and Development Ceter, Tokyo (Japan). Mechanical Systems Laboratory

2000-11-10

The effect of plasma formed gas on the plasma structure is investigated using a self consistent continuous fluid plasma model, which assumes that the local field approximation was attained in the RF plasma. The swarm parameter was obtained by Boltzmann analysis for O{sub 2} gas which contains various amounts of O radicals. Positive ion density, negative ion density, and electron density in the O{sub 2} RF plasma including O radical generation were calculated by self-consistent one dimensional continuous fluid plasma model. The calculation results show the dominant positive charged particle became O{sup +} from O{sub 2}{sup +} with increasing amount of O radical in O{sub 2}. The plasma positive densities are not greatly affected if O radical content did not exceed 1 % of O{sub 2}. It was concluded that O{sub 2} plasma structure can be evaluated by source gas plasma calculation neglecting radical formation, since O radical formation in the O{sub 2} plasma is estimated as less than 0.2 % of O{sub 2}. (author)
Al{sub 2}O{sub 3} reinforced nanoparticle ZrO{sub 2} (3at%?Y{sub 2}O{sub 3}); Al{sub 2}O{sub 3} reforcado com nanoparticulas de ZrO{sub 2}(3%mol Y{sub 2}O{sub 3})

Energy Technology Data Exchange (ETDEWEB)

Cossu, C.M.F.A.; Alves, M.F.R.P.; Campos, L.Q.B.; Magnago, R.O.; Santos, C., E-mail: caio.cossu@usp.br [Universidade do Estado do Rio de Janeiro (UERJ), Resende, RJ (Brazil). Faculdade de Tecnologia; Simba, B.G. [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Guaratingueta, SP (Brazil). Faculdade de Engenharia

2016-07-01

This work developed a composite Al{sub 2}O{sub 3}-based reinforced with nanoparticles of ZrO{sub 2} (Y{sub 2}O{sub 3}), to evaluate the effect of the content of ZrO{sub 2} nanoparticles (Y{sub 2}O{sub 3}) on the mechanical properties. Mixtures containing a matrix of Al{sub 2}O{sub 3} with fractions in weight of 3%, 5%, 10% and 15%, ZrO{sub 2} (Y{sub 2}O{sub 3}), and were mixed in mortar mill. Mixtures received 5% polymeric binder (PVA); and after adding the binder, the material was pressed uniaxially to 50MPa, and then sintered at a temperature of 1600 ° C - 2h. The sintered products were characterized by X-ray diffraction, scanning electron microscopy (SEM), relative density, hardness and fracture toughness. The results of X-ray diffraction showed that Al{sub 2}O{sub 3} and tetragonal ZrO{sub 2} as crystal phases found after sintering. Furthermore, the relative green density of 55% was predominant in the compact; and after sintering, varied depending on the ZrO{sub 2} content, reaching 97% in sintered compositions with 3% ZrO{sub 2} nanoparticles (Y{sub 2O}3). The hardness of the samples showed values of 1670HV and the maximum toughness of 3.2 MPa × m{sup 1/2}, directly influenced by the presence of nanoparticles ZrO{sub 2} uniformly dispersed in the matrix Al{sub 2}O{sub 3}, which results in at least two main mechanisms tenacifiers: transformation of tetragonal-monoclinic phase of zirconia, and compressive residual strain between the two phases present, Al{sub 2}O{sub 3} and tetragonal ZrO{sub 2}. (author)
Effect of efficient supply of pure O{sub 2} concentrated by PSA-type O{sub 2} separator on improvement of indoor air quality

Energy Technology Data Exchange (ETDEWEB)

Han, Gi Bo; Jang, Jung Hee; Choi, Changsik [Institute for Advanced Engineering, Yongin (Korea, Republic of); Lee, Tae Jin [School of Chemical Engineering Yeungnam University, Gyeongsan (Korea, Republic of)

2016-04-15

To minimize the cost and loss rate of energy artificial room ventilation system, the O{sub 2} separator was suggested for the flow of the excessive ventilation amount between indoor and outdoor because the pure O{sub 2} separated and concentrated by the O{sub 2} separator can be supplied with the ventilation amount minimized. How the O{sub 2} separator applies to ventilation and its operation characteristics were investigated by controlling under various conditions as well as the operation conditions optimized required for indoor air quality such as the concentration of CO{sub 2} and O{sub 2}. Consequently, it was known that the O{sub 2} concentration was increased; however, the increase of the CO{sub 2} concentration was suppressed by the sufficient supply of O{sub 2} concentrated from the storage tank into the room despite the two persons’ breathing in the room having an inner volume of about 56m{sup 3}. Consequently, it was concluded that the supply system of the concentrated O{sub 2} which was stored into the tank after the production with the O{sub 2} separator can be applied to the room ventilation system for the improvement of the indoor air quality.
Thermoresponsive behaviour of AM{sub 2}O{sub 8} materials

Energy Technology Data Exchange (ETDEWEB)

Allen, Simon

2003-07-01

This thesis investigates the synthesis and structural characterisation of AM{sub 2}O{sub 8} phases, many of which show negative thermal expansion (NTE); relevant literature is reviewed in Chapter One. Chapter Two describes the synthesis, structure solution, and mechanistic role of a new family of low-temperature (LT) orthorhombic AM{sub 2}O{sub 8} polymorphs (A{sup IV} = Zr, Hf; M{sup VI} = Mo, W). These materials are key intermediates in the preparation of cubic AM{sub 2}O{sub 8} phases from AM{sub 2}O{sub 7}(OH){sub 2}(H{sub 2}O){sub 2}. The structure of LT-AM{sub 2}O{sub 8} has been elucidated by combined laboratory X-ray and neutron powder diffraction. Variable temperature X-ray diffraction (VTXRD) studies have shown LT-AMo{sub 2}O{sub 8} phases exhibit anisotropic NTE. LT-ZrMo{sub 2}O{sub 8} has been shown to undergo spontaneous rehydration, allowing preparation of ZrMo{sub 2}O{sub 7}(OD){sub 2}(D{sub 2}O){sub 2} and assignment of D{sub 2}O/OD positions within the structure by neutron diffraction. Using this result, a reversible topotactic dehydration pathway from AM{sub 2}O{sub 7}(OH){sub 2}(H{sub 2}O){sub 2} to LT-AM{sub 2}O{sub 8} is proposed. Chapter Three investigates the order-disorder phase transition with concurrent oxygen mobility in cubic AM{sub 2}O{sub 8} materials; studies include comprehensive VT neutron diffraction of cubic ZrMo{sub 2}O{sub 8} to reveal a static to dynamic transition at 215 K, and novel quench-anneal/quench-warm variable temperature/time diffraction experiments on ZrWMoO{sub 8} which lead to an activation energy of 40 kJmol{sup -1} for oxygen migration. In Chapter Four {sup 17}O-labelled cubic ZrW{sub 2}O{sub 8} has been prepared to understand the oxygen migration process by VT MAS NMR. In situ hydrothermal studies of cubic ZrMo{sub 2}O{sub 8} using synchrotron radiation have shown direct hydration to ZrMo{sub 2}O{sub 7}(OH){sub 2}(H{sub 2}O){sub 2}. In Chapter Five VTXRD of trigonal {alpha}-AMo{sub 2}O{sub 8} phases reveals a
Facile synthesis and characterization of ZnFe{sub 2}O{sub 4}/{alpha}-Fe{sub 2}O{sub 3} composite hollow nanospheres

Energy Technology Data Exchange (ETDEWEB)

Shen, Yu [Key Laboratory of Industrial Ecology and Environmental Engineering and State Key Laboratory of Fine Chemical, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024 (China); School of Environmental and Chemical Engineering, Dalian Jiaotong University, Dalian 116028 (China); Li, Xinyong, E-mail: xyli@dlut.edu.cn [Key Laboratory of Industrial Ecology and Environmental Engineering and State Key Laboratory of Fine Chemical, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024 (China); Department of Chemical Engineering, Curtin University, Perth, WA 6845 (Australia); Zhao, Qidong; Hou, Yang [Key Laboratory of Industrial Ecology and Environmental Engineering and State Key Laboratory of Fine Chemical, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024 (China); Tade, Moses [Department of Chemical Engineering, Curtin University, Perth, WA 6845 (Australia); Liu, Shaomin, E-mail: Shaomin.Liu@curtin.edu.au [Department of Chemical Engineering, Curtin University, Perth, WA 6845 (Australia)

2011-12-15

Highlights: Black-Right-Pointing-Pointer ZnFe{sub 2}O{sub 4}/{alpha}-Fe{sub 2}O{sub 3} composite hollow nanospheres were successfully synthesized via a facile method. Black-Right-Pointing-Pointer Detailed structural, morphology and the phase composition were studied. Black-Right-Pointing-Pointer The incorporation of ZnFe{sub 2}O{sub 4} and {alpha}-Fe{sub 2}O{sub 3} gives an appropriate band gap value to utilize solar energy. -- Abstract: ZnFe{sub 2}O{sub 4}/{alpha}-Fe{sub 2}O{sub 3} composite hollow nanospheres were successfully fabricated via a facile one-pot solvothermal method, utilizing polyethylene glycol as soft template. X-ray diffraction and scanning electron microscopy analysis revealed that the prepared nanospheres with cubic spinel and rhombohedra composite structure had a uniform diameter of about 370 nm, and the hollow structure could be further confirmed by transmission electron microscopy. Energy dispersive X-ray, X-ray photoelectron spectroscopy and Fourier transform infrared techniques were also applied to characterize the elemental composition and chemical bonds in the hollow nanospheres. The ZnFe{sub 2}O{sub 4}/{alpha}-Fe{sub 2}O{sub 3} composite hollow nanospheres show attractive light absorption property for potential applications in electronics, optics, and catalysis.
Effect of As/sub 2/O/sub 3/ on gluconeogenesis

Energy Technology Data Exchange (ETDEWEB)

Szinicz, L.; Forth, W.

1988-06-01

The effect of As/sub 2/O/sub 3/ and As/sub 2/O/sub 5/ on gluconeogenesis from various substrates in the liver and kidney of rats was investigated. A concentration-dependent inhibition by As/sub 2/O/sub 3/ was found. The highest degree of inhibition was observed in incubations with pyruvate. The inhibition of glucose formation was accompanied to a lesser extent by a diminution in O/sub 2/ consumption and ATP content. The effect was also dependent on the substrate used. Oleate, 0,5 mmol/l, increased gluconeogenesis from pyruvate. The effect was not abolished by As/sub 2/O/sub 3/. A decrease in the content of acetyl-CoA, 3-hydroxybutyrate, and reduced glutathione was found in suspensions of isolated rat kidney tubules or hepatocytes incubated with As/sub 2/O/sub 3/. About 10 times higher concentrations of As/sub 2/O/sub 5/ were necessary to induce a similar extent of inhibition of gluconeogenesis, decrease in O/sub 2/ consumption, and in ATP content as compared with As/sub 2/O/sub 3/. Gluconeogenesis from pyruvate exhibited highest sensitivity to As/sub 2/O/sub 5/. Starved rats were shown to be much more sensitive to As/sub 2/O/sub 3/ than animals with free access to food.
Ultrasonic-assisted in situ synthesis and characterization of superparamagnetic Fe{sub 3}O{sub 4} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Feng Jie [College of Materials Science and Engineering, Sichuan University, Chengdu 610064 (China); Mao Jian, E-mail: maojianemail@163.com [College of Materials Science and Engineering, Sichuan University, Chengdu 610064 (China); Wen Xiaogang; Tu Mingjing [College of Materials Science and Engineering, Sichuan University, Chengdu 610064 (China)

2011-09-15

Highlights: > Fe{sup 3+} as the only Fe source for preparing Fe{sub 3}O{sub 4} nanoparticles through in situ cover and sonication method. > Surface modification enables the reduction of the grain size of Fe{sub 3}O{sub 4}. > Increasing temperature reduces grain size of Fe{sub 3}O{sub 4} until it exceeds 80 deg. C. > Increasing pH values reduces grain size of Fe{sub 3}O{sub 4} until it exceeds 11. > Saturation magnetizations depend on the grain size of Fe{sub 3}O{sub 4} nanoparticles. - Abstract: Superparamagnetic Fe{sub 3}O{sub 4} nanoparticles were synthesized via a modified coprecipitation method, and were characterized with X-ray diffraction (XRD), vibrating sample magnetometer (VSM), Zeta potential and FT-IR, respectively. The influences of different kinds of surfactants (sodium dodecyl benzene sulfonate, polyethyleneglycol, oleic acid and dextran), temperatures and pH values on the grain size and properties were also investigated. In this method, Fe{sup 3+} was used as the only Fe source and partially reduced to Fe{sup 2+} by the reducing agent with precise content. The following reaction between Fe{sup 3+}, Fe{sup 2+} and hydroxide radical brought pure Fe{sub 3}O{sub 4} nanoparticles. The tiny fresh nanoparticles were coated in situ with surfactant under the action of sonication. Comparing with uncoated sample, the mean grain size and saturation magnetization of coated Fe{sub 3}O{sub 4} nanoparticles decrease from 18.4 nm to 5.9-9.0 nm, and from 63.89 emu g{sup -1} to 52-58 emu g{sup -1} respectively. When oleic was used as the surfactant, the mean grain size of Fe{sub 3}O{sub 4} nanoparticles firstly decreases with the increase of reaction temperature, but when the temperature is exceed to 80 deg. C, the continuous increase of temperature resulted in larger nanoparticles. the grain size decreases gradually with the increasing of pH values, and it remains unchanged when the PH value is up to 11. The saturation magnetization of as-prepared Fe{sub 3}O{sub 4
Resolving the ambiguity: Making sense of intrinsic disorder when PDB structures disagree.

Science.gov (United States)

DeForte, Shelly; Uversky, Vladimir N

2016-03-01

Missing regions in X-ray crystal structures in the Protein Data Bank (PDB) have played a foundational role in the study of intrinsically disordered protein regions (IDPRs), especially in the development of in silico predictors of intrinsic disorder. However, a missing region is only a weak indication of intrinsic disorder, and this uncertainty is compounded by the presence of ambiguous regions, where more than one structure of the same protein sequence "disagrees" in terms of the presence or absence of missing residues. The question is this: are these ambiguous regions intrinsically disordered, or are they the result of static disorder that arises from experimental conditions, ensembles of structures, or domain wobbling? A novel way of looking at ambiguous regions in terms of the pattern between multiple PDB structures has been demonstrated. It was found that the propensity for intrinsic disorder increases as the level of ambiguity decreases. However, it is also shown that ambiguity is more likely to occur as the protein region is placed within different environmental conditions, and even the most ambiguous regions as a set display compositional bias that suggests flexibility. The results suggested that ambiguity is a natural result for many IDPRs crystallized under different conditions and that static disorder and wobbling domains are relatively rare. Instead, it is more likely that ambiguity arises because many of these regions were conditionally or partially disordered. © 2016 The Protein Society.
Carbon and oxygen isotopes in carbonatites from Puna, Jujuy and Salta, Argentina; Isotopos de carbono y oxigeno en carbonatitas en la Puna Oriental, Provincias de Jujuy y Salta, Republica Argentina

Energy Technology Data Exchange (ETDEWEB)

Zappettini, Eduardo O; Rubiolo, Daniel [Servicio Geologico Minero Argentino (SEGEMAR), Buenos Aires (Argentina). Instituto de Geologia y Recursos Naturales; Hubberten, Hans W [Alfred-Wegener-Institut fuer Polar- und Meeresforschung, Bremerhaven (Germany)

1998-07-01

{delta}{sup 13} and {delta}{sup 18}O data from carbonatites indicate that bodies formed by crystallization of carbonate magma with subsequent formation of metasomatic and hydrothermal carbonatitic veins. The isotopic data are consistent with the available geochemical and petrologic information. (author)
Stable isotope compositions of quartz pebbles and their fluid inclusions as tracers of sediment provenance: Implications for gold- and uranium-bearing quartz pebble conglomerates

Energy Technology Data Exchange (ETDEWEB)

Vennemann, T.W.; Kesler, S.E.; O' Neil, J.R. (Univ. of Michigan, Ann Arbor (United States))

1992-09-01

Oxygen isotope compositions of pebbles from late Archean to paleo-Proterozoic gold- and/or uranium-bearing oligomictic quartz pebble conglomerates of the Witwatersrand district, South Africa, and Huronian Supergroup, Canada, were determined in an attempt to define the nature of the source terrain. The [delta][sup 18]O values of quartz pebbles within any one sample typically vary by [approximately] 4[per thousand] or more, but occasionally by as much as 8[per thousand], even for adjacent pebbles within the same hand specimen. In addition, adjacent quartz pebbles of widely contrasting [delta][sup 18]O values also preserve distinct isotopic signatures of their fluid inclusions. This overall heterogeneity suggests that the pebbles did not undergo significant oxygen isotope exchange after incorporation in the conglomerates. Therefore, oxygen isotope analyses of such quartz pebbles, in combination with a detailed investigation of their mineral and fluid inclusions, can provide a useful method for characterizing pebble populations and hence dominant sediment source modes. Comparison of values found in this study with [delta][sup 18]O values of quartz from Archean granites, pegmatites, and mesothermal greenstone gold veins, i.e., [delta][sup 18]O values of sources commonly proposed for the conglomerate ores, suggests that uranium is derived from a granitic source, whereas gold has a mesothermal greenstone gold source. Low [delta][sup 18]O values of chert pebbles (9[per thousand] to 11.5[per thousand]) relative to those expected for Archean and Proterozoic marine cherts (commonly [ge] 17[per thousand]) effectively exclude marine cherts, and therefore, auriferous iron formations and exhalatives, as likely sources of gold.
Fabrication and luminescence properties of Al{sub 2}O{sub 3}:Tb{sup 3+} microspheres via a microwave solvothermal route

Energy Technology Data Exchange (ETDEWEB)

Zhu Zhenfeng, E-mail: zhuzf@sust.edu.cn [School of Materials Science and Engineering, Shaanxi University of Science and Technology, Xi' an 710021 (China); Liu Dianguang; Liu Hui; Li Guangjun; Du Juan; He Zuoli [School of Materials Science and Engineering, Shaanxi University of Science and Technology, Xi' an 710021 (China)

2012-02-15

Al{sub 2}O{sub 3}:Tb{sup 3+} green phosphors were synthesized via a microwave solvothermal and thermal decomposition route, and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), photoluminescence (PL) spectra, and decay curves. XRD results indicate that Tb{sup 3+} doped samples are {gamma}-Al{sub 2}O{sub 3} after being calcined at 773 K. SEM results show that the particles of Al{sub 2}O{sub 3}:Tb{sup 3+} are hierarchically nanostructured microspheres assembled from nanosheets. The PL spectra indicate that the {sup 5}D{sub 4}{yields}{sup 7}F{sub 5} (545 nm) electric dipole transition is the most intensive when excited at 235 nm. It is shown that 0.7 mol% of doping concentration of Tb{sup 3+} ions in {gamma}-Al{sub 2}O{sub 3}:Tb{sup 3+} is optimum. According to Dexter's theory, the critical distance between Tb{sup 3+} ions for energy transfer was determined to be 18.4 A. It is found that the curve followed the single-exponential decay. The excellent chromaticity coordinates of Al{sub 2}O{sub 3}:Tb{sup 3+} phosphors, as defined by the International Commission on Illumination (CIE), indicate that it is a good candidate for use in light display systems and optoelectronic devices. - Highlights: Black-Right-Pointing-Pointer Al{sub 2}O{sub 3}:Tb{sup 3+} phosphors prepared via a microwave solvothermal route. Black-Right-Pointing-Pointer The particles were hierarchically nanostructured microspheres packaged by nanosheets. Black-Right-Pointing-Pointer {sup 5}D{sub 4}{yields}{sup 7}F{sub 5} electric dipole transition is the most intensive when excited at 235 nm. Black-Right-Pointing-Pointer 0.7 mol% of doping concentration of Tb{sup 3+} ions in {gamma}-Al{sub 2}O{sub 3}:Tb{sup 3+} is optimum. Black-Right-Pointing-Pointer Critical distance between Tb{sup 3+} ions for energy transfer is 18.4 A.
Kinetic control in the synthesis of metastable polymorphs: Bixbyite-to-Rh{sub 2}O{sub 3}(II)-to-corundum transition in In{sub 2}O{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Bekheet, Maged F., E-mail: maged.bekheet@ceramics.tu-berlin.de [Fachbereich Material -und Geowissenschaften, Technische Universität Darmstadt, Alarich-Weiss-Straße 2, 64287 Darmstadt (Germany); Fachgebiet Keramische Werkstoffe, Institut für Werkstoffwissenschaften und -technologien, Technische Universität Berlin, Hardenbergstraße 40, 10623 Berlin (Germany); Schwarz, Marcus R. [Freiberg High Pressure Research Centre, Institut für Anorganische Chemie, Technische Universität-Bergakademie Freiberg, Leipziger Straße 29, 09599 Freiberg (Germany); Kroll, Peter [Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX 760019-0065 (United States); Gurlo, Aleksander [Fachbereich Material -und Geowissenschaften, Technische Universität Darmstadt, Alarich-Weiss-Straße 2, 64287 Darmstadt (Germany); Fachgebiet Keramische Werkstoffe, Institut für Werkstoffwissenschaften und -technologien, Technische Universität Berlin, Hardenbergstraße 40, 10623 Berlin (Germany)

2015-09-15

An example for kinetic control of a solid-state phase transformation, in which the system evolves via the path with the lowest activation barrier rather than ending in the thermodynamically most favorable state, has been demonstrated. As a case study, the phase transitions of indium sesquioxide (In{sub 2}O{sub 3}) have been guided by theoretical calculations and followed in situ under high-pressure high-temperature conditions in multi-anvil assemblies. The corundum-type rh-In{sub 2}O{sub 3} has been synthesized from stable bixbyite-type c-In{sub 2}O{sub 3} in two steps: first generating orthorhombic Rh{sub 2}O{sub 3}-II-type o′-In{sub 2}O{sub 3} which is thermodynamically stable at 8.5 GPa/850 °C and, thereafter, exploiting the preferred kinetics in the subsequent transformation to the rh-In{sub 2}O{sub 3} during decompression. This synthesis strategy of rh-In{sub 2}O{sub 3} was confirmed ex situ in a toroid-type high-pressure apparatus at 8 GPa and 1100 °C. The pressure–temperature phase diagrams have been constructed and the stability fields of In{sub 2}O{sub 3} polymorphs and the crystallographic relationship between them have been discussed. - Graphical abstract: In situ energy-dispersive XRD patterns in multi-anvil assemblies show the sequence of phase transition c-In{sub 2}O{sub 3}→o′-In{sub 2}O{sub 3}→rh-In{sub 2}O{sub 3} under particular pressure and temperature conditions. The tick marks refer to the calculated Bragg positions of bixbyite-type (c-In{sub 2}O{sub 3}), Rh{sub 2}O{sub 3}-II-type (o–-In2O{sub 3}) and corundum-type (rh-In{sub 2}O{sub 3}). - Highlights: • The solid-state synthesis methods can be employed for obtaining metastable phases. • The phase transition of In{sub 2}O{sub 3} was guided by DFT calculations. • The phase transition of In{sub 2}O{sub 3} was followed in situ under HP–HT conditions. • Orthorhombic o′-In{sub 2}O{sub 3} polymorph was synthesized from c-In{sub 2}O{sub 3} at 8.5 GPa/850 °C. • Metastable rh
Microwave dielectric properties of CaCu{sub 3}Ti{sub 4}O{sub 12}-Al{sub 2}O{sub 3} composite

Energy Technology Data Exchange (ETDEWEB)

Rahman, Mohd Fariz Ab; Abu, Mohamad Johari; Zaman, Rosyaini Afindi; Ahmad, Zainal Arifin [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Karim, Saniah Ab; Mohamed, Julie Juliewatty, E-mail: juliewatty.m@umk.edu.my [Advance Materials Research Cluster, Faculty of Earth Sciences, Universiti Malaysia Kelantan, Jeli Campus, 17600 Jeli, Kelantan (Malaysia); Ain, Mohd Fadzil [School of Electrical and Electronic Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia)

2016-07-19

(1-x)CaCu{sub 3}Ti{sub 4}O{sub 12} + (x)Al{sub 2}O{sub 3} composite (0 ≤ x ≤0.25) was prepared via conventional solid-state reaction method. The fabrication of sample was started with synthesizing stoichiometric CCTO from CaCO{sub 3}, CuO and TiO{sub 2} powders, then wet-mixed in deionized water for 24 h. The process was continued with calcined CCTO powder at 900 °C for 12 h before sintered at 1040 °C for 10 h. Next, the calcined CCTO powder with different amount of Al{sub 2}O{sub 3} were mixed for 24 h, then palletized and sintered at 1040 °C for 10. X-ray diffraction analysis on the sintered samples showed that CCTO powder was in a single phase, meanwhile the trace of secondary peaks which belong to CaAl{sub 2}O{sub 4} and Corundum (Al{sub 2}O{sub 3}) could be observed in the other samples Scanning electron microscopy analysis showed that the grain size of the sample is firstly increased with addition of Al{sub 2}O{sub 3} (x = 0.01), then become smaller with the x > 0.01. Microwave dielectric properties showed that the addition of Al{sub 2}O{sub 3} (x = 0.01) was remarkably reduced the dielectric loss while slightly increased the dielectric permittivity. However, further addition of Al{sub 2}O{sub 3} was reduced both dielectric loss and permittivity at least for an order of magnitude.
Magnéli phases Ti{sub 4}O{sub 7} and Ti{sub 8}O{sub 15} and their carbon nanocomposites via the thermal decomposition-precursor route

Energy Technology Data Exchange (ETDEWEB)

Conze, S., E-mail: susan.conze@ikts.fraunhofer.de [Fraunhofer Institute for Ceramic Technologies and Systems IKTS, Winterbergstr. 28, 01277 Dresden (Germany); Veremchuk, I. [Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden (Germany); Reibold, M. [Technical University of Dresden, Zum Triebenberg 50, 01328 Dresden (Zaschendorf) (Germany); Matthey, B.; Michaelis, A. [Fraunhofer Institute for Ceramic Technologies and Systems IKTS, Winterbergstr. 28, 01277 Dresden (Germany); Grin, Yu. [Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden (Germany); Kinski, I. [Fraunhofer Institute for Ceramic Technologies and Systems IKTS, Winterbergstr. 28, 01277 Dresden (Germany)

2015-09-15

A new synthetic approach for producing nano-powders of the Magnéli phases Ti{sub 4}O{sub 7}, Ti{sub 8}O{sub 15} and their carbon nanocomposites by thermal decomposition-precursor route is proposed. The formation mechanism of the single-phase carbon nanocomposites (Ti{sub 4}O{sub 7}/C and Ti{sub 8}O{sub 15}/C) from metal–organic precursors is studied using FT-IR, elemental analysis, TG, STA-MS and others. The synthesis parameters and conditions were optimized to prepare the target oxides with the desired microstructure and physical properties. The electrical and transport properties of Ti{sub 4}O{sub 7}/C and Ti{sub 8}O{sub 15}/C are investigated. These nano-materials are n-type semiconductors with relatively low thermal conductivity in contrast to the bulk species. The nanostructured carbon nanocomposites of Magnéli phases achieve a low thermal conductivity close to 1 W/m K at RT. The maximum ZT{sub 570} {sub °C} values are 0.04 for Ti{sub 4}O{sub 7}/C powder nanocomposite and 0.01 for Ti{sub 8}O{sub 15}/C bulk nanocomposite. - Graphical abstract: From the precursor to the produced titanium oxide pellet and its microstructure (SEM, TEM micrographs) as well as results of phase and thermoelectric analyses. - Highlights: • Magnéli phases Ti{sub 4}O{sub 7}/Ti{sub 8}O{sub 15} via thermal decomposition-precursor route is proposed. • The formation mechanism of the nanocomposites Ti{sub 4}O{sub 7}/C and Ti{sub 8}O{sub 15}/C are investigated. • Microstructure of Ti{sub 4}O{sub 7}/C and Ti{sub 8}O{sub 15}/C are examined. • The electrical and transport properties of Ti{sub 4}O{sub 7}/C and Ti{sub 8}O{sub 15}/C are investigated. • The maximum figure of mertit ZT{sub 570} {sub °C} of Ti{sub 4}O{sub 7}/C and Ti{sub 8}O{sub 15}/C are 0.01 and 0.04.
{sup 2}H NMR and {sup 13}C-IRMS analyses of acetic acid from vinegar, {sup 18}O-IRMS analysis of water in vinegar: International collaborative study report

Energy Technology Data Exchange (ETDEWEB)

Thomas, Freddy [Eurofins Scientific Analytics, BP42301, 44323 Nantes (France); Jamin, Eric [Eurofins Scientific Analytics, BP42301, 44323 Nantes (France)

2009-09-01

An international collaborative study of isotopic methods applied to control the authenticity of vinegar was organized in order to support the recognition of these procedures as official methods. The determination of the {sup 2}H/{sup 1}H ratio of the methyl site of acetic acid by SNIF-NMR (site-specific natural isotopic fractionation-nuclear magnetic resonance) and the determination of the {sup 13}C/{sup 12}C ratio, by IRMS (isotope ratio mass spectrometry) provide complementary information to characterize the botanical origin of acetic acid and to detect adulterations of vinegar using synthetic acetic acid. Both methods use the same initial steps to recover pure acetic acid from vinegar. In the case of wine vinegar, the determination of the {sup 18}O/{sup 16}O ratio of water by IRMS allows to differentiate wine vinegar from vinegars made from dried grapes. The same set of vinegar samples was used to validate these three determinations. The precision parameters of the method for measuring {delta}{sup 13}C (carbon isotopic deviation) were found to be similar to the values previously obtained for similar methods applied to wine ethanol or sugars extracted from fruit juices: the average repeatability (r) was 0.45 per mille , and the average reproducibility (R) was 0.91 per mille . As expected from previous in-house study of the uncertainties, the precision parameters of the method for measuring the {sup 2}H/{sup 1}H ratio of the methyl site were found to be slightly higher than the values previously obtained for similar methods applied to wine ethanol or fermentation ethanol in fruit juices: the average repeatability was 1.34 ppm, and the average reproducibility was 1.62 ppm. This precision is still significantly smaller than the differences between various acetic acid sources ({delta}{sup 13}C and {delta}{sup 18}O) and allows a satisfactory discrimination of vinegar types. The precision parameters of the method for measuring {delta}{sup 18}O were found to be similar
Magnetic and luminescent properties of Fe/Fe{sub 3}O{sub 4}-Y{sub 2}O{sub 3}:Eu nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Wang Qin [College of Chemistry, Jilin University, Changchun 130012 (China); College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot (China); Yang Xuwei; Yu Lianxiang [College of Chemistry, Jilin University, Changchun 130012 (China); Yang Hua, E-mail: huayang86@sina.com [College of Chemistry, Jilin University, Changchun 130012 (China)

2011-09-15

Highlights: > We synthesize multifunctional Fe/Fe{sub 3}O{sub 4}-Y{sub 2}O{sub 3}:Eu nanocomposites. > The luminescent and magnetic properties of the nanocomposites are researched. > The nanocomposites showed both ferrimagnetic behavior and unique europium fluorescence properties with high emission intensity. > The spectra changes induced by the UV light irradiation and the magnetic field have been systematically studied and compared in detail. > And the hysteresis curve changes induced by the UV light irradiation have been discussed. - Abstract: Multifunctional nanocomposites with Fe/Fe{sub 3}O{sub 4} nanoparticles as the core and europium-doped yttrium oxide (Y{sub 2}O{sub 3}:Eu) as the shell (Fe/Fe{sub 3}O{sub 4}-Y{sub 2}O{sub 3}:Eu) have been obtained successfully employing a solvothermal method. The nanocomposites showed both ferrimagnetic behavior and unique europium fluorescence properties with high emission intensity. The spectra changes induced by the UV light irradiation and the magnetic field have been systematically studied and compared in detail. The relationship between fluorescence and magnetic properties of the multifunctional nanocomposites has been investigated in our manuscript. These multifunctional nanocomposites could be used in a number of biomedical applications, such as drug targeting, cell separation and bioimaging.
Interfacial reactions of Ba{sub 2}YCu{sub 3}O{sub 6+z} with coated conductor buffer layer, LaMnO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Liu, G. [Ceramics Division, National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Wong-Ng, W., E-mail: winnie.wong-ng@nist.go [Ceramics Division, National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Kaduk, J.A. [Poly Crystallography Inc., Naperville, IL 60540 (United States); Cook, L.P. [Ceramics Division, National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States)

2010-03-01

Chemical interactions between the Ba{sub 2}YCu{sub 3}O{sub 6+x} superconductor and the LaMnO{sub 3} buffer layers employed in coated conductors have been investigated experimentally by determining the phases formed in the Ba{sub 2}YCu{sub 3}O{sub 6+x}-LaMnO{sub 3} system. The Ba{sub 2}YCu{sub 3}O{sub 6+x}-LaMnO{sub 3} join within the BaO-(Y{sub 2}O{sub 3}-La{sub 2}O{sub 3})-MnO{sub 2}-CuO{sub x} multi-component system is non-binary. At 810 deg. C (p{sub O2} = 100 Pa) and at 950 deg. C in purified air, four phases are consistently present along the join, namely, Ba{sub 2-x}(La{sub 1+x-y}Y{sub y})Cu{sub 3}O{sub 6+z}, Ba(Y{sub 2-x}La{sub x})CuO{sub 5}, (La{sub 1-x}Y{sub x})MnO{sub 3}, (La,Y)Mn{sub 2}O{sub 5}. The crystal chemistry and crystallography of Ba(Y{sub 2-x}La{sub x})CuO{sub 5} and (La{sub 1-x}Y{sub x})Mn{sub 2}O{sub 5} were studied using the X-ray Rietveld refinement technique. The Y-rich and La-rich solid solution limits for Ba(Y{sub 2-x}La{sub x})CuO{sub 5} are Ba(Y{sub 1.8}La{sub 0.2})CuO{sub 5} and Ba(Y{sub 0.1}La{sub 1.9})CuO{sub 5}, respectively. The structure of Ba(Y{sub 1.8}La{sub 0.2})CuO{sub 5} is Pnma (No. 62), a = 12.2161(5) A, b = 5.6690(2) A, c = 7.1468(3) A, V = 494.94(4) A{sup 3}, and D{sub x} = 6.29 g cm{sup -3}. YMn{sub 2}O{sub 5} and LaMn{sub 2}O{sub 5} do not form solid solution at 810 deg. C (p{sub O2} = 100 Pa) or at 950 deg. C (in air). The structure of YMn{sub 2}O{sub 5} was confirmed to be Pbam (No. 55), a = 7.27832(14) A, b = 8.46707(14) A, c = 5.66495(10) A, and V = 349.108(14) A{sup 3}. A reference X-ray pattern was prepared for YMn{sub 2}O{sub 5}.
Fabrication of heterostructured Bi{sub 2}O{sub 2}CO{sub 3}/Bi{sub 2}O{sub 4} photocatalyst and efficient photodegradation of organic contaminants under visible-light

Energy Technology Data Exchange (ETDEWEB)

Sun, Meng; Li, Shuangli; Yan, Tao; Ji, Pengge; Zhao, Xia; Yuan, Kun; Wei, Dong [School of Resources and Environment, University of Jinan, Jinan 250022 (China); Du, Bin, E-mail: dubin61@gmail.com [School of Resources and Environment, University of Jinan, Jinan 250022 (China); Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022 (China)

2017-07-05

Highlights: • The product shows efficient activity in photodegradation of RhB, BPA, and phenol. • The BBOC-10 heterojunction exhibits the best activity under visible light. • Suppressed recombination of photo-generated carriers lead to the activity enhancement. - Abstract: Heterostructured Bi{sub 2}O{sub 2}CO{sub 3}/Bi{sub 2}O{sub 4} photocatalysts were fabricated by a facile one-pot hydrothermal method, in which melem served as the sacrificial reagent to supply carbonate anions. The as-synthesized Bi{sub 2}O{sub 2}CO{sub 3}/Bi{sub 2}O{sub 4} heterojunction catalysts were characterized by X-ray diffraction, UV–vis diffuse reflectance spectra, X-ray photoelectron spectroscopy, scanning electron microscope, and transmission electron microscope. The XRD patterns of Bi{sub 2}O{sub 2}CO{sub 3}/Bi{sub 2}O{sub 4} catalysts showed the distinctive peaks of Bi{sub 2}O{sub 2}CO{sub 3} and Bi{sub 2}O{sub 4}. The SEM and TEM results showed that the pure Bi{sub 2}O{sub 2}CO{sub 3} possessed large plate morphology, while Bi{sub 2}O{sub 4} were composed of various nanorods and particles. As for Bi{sub 2}O{sub 2}CO{sub 3}/Bi{sub 2}O{sub 4} heterojunction, it was obviously observed that Bi{sub 2}O{sub 4} nanorods and particles were grown on the surfaces of Bi{sub 2}O{sub 2}CO{sub 3} plates. The visible light driven photocatalytic activity of Bi{sub 2}O{sub 2}CO{sub 3}/Bi{sub 2}O{sub 4} heterojunction photocatalyst was evaluated by decomposing dyes, phenol, and bisphenol A in water. Compared with Bi{sub 2}O{sub 2}CO{sub 3} and Bi{sub 2}O{sub 4}, the Bi{sub 2}O{sub 2}CO{sub 3}/Bi{sub 2}O{sub 4} photocatalysts have exhibited remarkable enhanced activity under visible light. The excellent activity can be mainly attributed to the enhanced separation efficiency of photo-generated carriers. Controlled experiments using different radical scavengers proved that ·O{sub 2}{sup −} and h{sup +} played the main role in decomposing organic pollutants. The results of this work would
Thermal decomposition of (UO{sub 2})O{sub 2}(H{sub 2}O){sub 2}·2H{sub 2}O: Influence on structure, microstructure and hydrofluorination

Energy Technology Data Exchange (ETDEWEB)

Thomas, R. [Univ. Lille, CNRS, Centrale Lille, ENSCL, Univ. Artois, UMR 8181 - UCCS - Unité de Catalyse et Chimie du Solide, F-59000 Lille (France); Hall de Recherche de Pierrelatte, AREVA NC, BP 16, 26701 Pierrelatte (France); Rivenet, M., E-mail: murielle.rivenet@ensc-lille.fr [Univ. Lille, CNRS, Centrale Lille, ENSCL, Univ. Artois, UMR 8181 - UCCS - Unité de Catalyse et Chimie du Solide, F-59000 Lille (France); Berrier, E. [Univ. Lille, CNRS, Centrale Lille, ENSCL, Univ. Artois, UMR 8181 - UCCS - Unité de Catalyse et Chimie du Solide, F-59000 Lille (France); Waele, I. de [Université de Lille, CNRS, UMR 8516 – LASIR - Laboratoire de Spectrochimie Infrarouge et Raman, F-59000 Lille (France); Arab, M.; Amaraggi, D.; Morel, B. [Hall de Recherche de Pierrelatte, AREVA NC, BP 16, 26701 Pierrelatte (France); Abraham, F. [Univ. Lille, CNRS, Centrale Lille, ENSCL, Univ. Artois, UMR 8181 - UCCS - Unité de Catalyse et Chimie du Solide, F-59000 Lille (France)

2017-01-15

The thermal decomposition of uranyl peroxide tetrahydrate, (UO{sub 2})O{sub 2}(H{sub 2}O){sub 2}.2H{sub 2}O, was studied by combining high temperature powder X-ray diffraction, scanning electron microscopy, thermal analyses and spectroscopic techniques (Raman, IR and {sup 1}H NMR). In situ analyses reveal that intermediates and final uranium oxides obtained upon heating are different from that obtained after cooling at room temperature and that the uranyl precursor used to synthesize (UO{sub 2})O{sub 2}(H{sub 2}O){sub 2}·2H{sub 2}O, sulfate or nitrate, has a strong influence on the peroxide thermal behavior and morphology. The decomposition of (UO{sub 2})O{sub 2}(H{sub 2}O){sub 2}·2H{sub 2}O ex sulfate is pseudomorphic and leads to needle-like shaped particles of metastudtite, (UO{sub 2})O{sub 2}(H{sub 2}O){sub 2}, and UO{sub 3-x}(OH){sub 2x}·zH{sub 2}O, an amorphous phase found in air in the following of (UO{sub 2})O{sub 2}(H{sub 2}O){sub 2} dehydration. (UO{sub 2})O{sub 2}(H{sub 2}O){sub 2}·2H{sub 2}O and the compounds resulting from its thermal decomposition are very reactive towards hydrofluorination as long as their needle-like morphology is kept.

Density functional study on the heterogeneous oxidation of NO over α-Fe{sub 2}O{sub 3} catalyst by H{sub 2}O{sub 2}: Effect of oxygen vacancy

Energy Technology Data Exchange (ETDEWEB)

Song, Zijian, E-mail: szj22zc15@163.com [State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, 430074, Wuhan (China); Wang, Ben, E-mail: benwang@hust.edu.cn [State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, 430074, Wuhan (China); Yu, Jie, E-mail: yujie@hust.edu.cn [State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, 430074, Wuhan (China); Ma, Chuan, E-mail: machuan628@163.com [State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, 430074, Wuhan (China); Zhou, Changsong, E-mail: zhouchangsong@hust.edu.cn [School of Energy and Mechanical Engineering, Nanjing Normal University, 210042, Nanjing (China); Chen, Tao, E-mail: chentao_hust@foxmail.com [State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, 430074, Wuhan (China); Yan, Qianqian [State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, 430074, Wuhan (China); Wang, Ke, E-mail: m201570959@hust.edu.cn [State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, 430074, Wuhan (China); Sun, Lushi, E-mail: sunlushi@hust.edu.cn [State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, 430074, Wuhan (China)

2017-08-15

Highlights: • NO and H{sub 2}O{sub 2} adsorption on perfect and oxygen defect α-Fe{sub 2}O{sub 3} (0 0 1) surface were studied by DFT calculations. • H{sub 2}O{sub 2} shows high chemical reactivity for its adsorption on oxygen defect α-Fe{sub 2}O{sub 3} (0 0 1) surface. • Oxygen vacancy plays an important role of the catalytic oxidation of NO by H{sub 2}O{sub 2} over the α-Fe{sub 2}O{sub 3} catalyst surfaces. • Mechanism of NO oxidation over α-Fe{sub 2}O{sub 3} (0 0 1) surface by H{sub 2}O{sub 2} was explained. - Abstract: Catalytic oxidation with H{sub 2}O{sub 2} is a promising method for NOx emission control in coal-fired power plants. Hematite-based catalysts are attracting increased attention because of their surface redox reactivity. To elucidate the NO oxidation mechanism on α-Fe{sub 2}O{sub 3} surfaces, density functional theory (DFT) calculations were conducted by investigating the adsorption characteristics of nitric oxide (NO) and hydrogen peroxide (H{sub 2}O{sub 2}) on perfect and oxygen defect α-Fe{sub 2}O{sub 3} (0 0 1) surfaces. Results show that NO was molecularly adsorbed on two kinds of surfaces. H{sub 2}O{sub 2} adsorption on perfect surface was also in a molecular form; however, H{sub 2}O{sub 2} dissociation occurred on oxygen defect α-Fe{sub 2}O{sub 3} (0 0 1) surface. The adsorption intensities of the two gas molecules in perfect α-Fe{sub 2}O{sub 3} (0 0 1) surface followed the order NO > H{sub 2}O{sub 2}, and the opposite was true for the oxygen defect α-Fe{sub 2}O{sub 3} (0 0 1). Oxygen vacancy remarkably enhanced the adsorption intensities of NO and H{sub 2}O{sub 2} and promoted H{sub 2}O{sub 2} decomposition on catalyst surface. As an oxidative product of NO, HNO{sub 2} was synthesized when NO and H{sub 2}O{sub 2} co-adsorbed on the oxygen defect α-Fe{sub 2}O{sub 3} (0 0 1) surface. Analyses of Mulliken population, electron density difference, and partial density of states showed that H{sub 2}O{sub 2} decomposition
Preparation and microwave-absorbing property of EP/BaFe{sub 12}O{sub 19}/PANI composites

Energy Technology Data Exchange (ETDEWEB)

Feng, Huixia, E-mail: fenghx@lut.cn [State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals, Lanzhou University of Technology, Lanzhou 730050 (China); College of Petrochemical Technology, Lanzhou University of Technology, Lanzhou 730050 (China); Bai, Dezhong [College of Petrochemical Technology, Lanzhou University of Technology, Lanzhou 730050 (China); Tan, Lin; Chen, Nali [State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals, Lanzhou University of Technology, Lanzhou 730050 (China); College of Petrochemical Technology, Lanzhou University of Technology, Lanzhou 730050 (China); Wang, Yueyi [College of Petrochemical Technology, Lanzhou University of Technology, Lanzhou 730050 (China)

2017-07-01

In this paper, we introduced expanded perlite (EP) into the system of ferrite composites for the first time. By sol-gel self-propagating combustion method, expanded perlite/barium ferrite (EP/BaFe{sub 12}O{sub 19}) was prepared, and then ternary composites of expanded perlite/barium ferrite/polyaniline (EP/BaFe{sub 12}O{sub 19}/PANI) were obtained by in-situ oxidative polymerization of aniline on EP/BaFe{sub 12}O{sub 19} mixture. Although, as is well known, the values of saturation magnetization (Ms), remnant magnetization (Mr) and coercivity (Hc) of composites are all lower than the pure BaFe{sub 12}O{sub 19} particles owing to the existence of the nonmagnetic EP and PANI, the EP/BaFe{sub 12}O{sub 19}/PANI composites exhibit absorption characteristics at the range of 2–18 GHz, the effective absorption bandwidth (less than −4 dB) reached 12.12 GHz and the minimum reflection loss of −5.66 dB at 8.48 GHz with only 2 mm thickness of absorbing layer. So the composites could resist urban electromagnetic pollution, such as wireless network, communication and so on, effectively. - Highlights: • The expanded perlite (EP) was introduced into the system of ferrite composites at the first time. • Novel ternary nanocomposite of EP/BaFe{sub 12}O{sub 19}/PANI is prepared by in-situ oxidative polymerization. • Composite absorber exhibit a minimum reflection loss of -5.66 dB at 8.48 GHz with a matching thickness of 2 mm. • Composite absorber possess the features like low-cost, lightweight and wide bandwidth absorption of civil EM radiation.
Nitration of toluene with N[sub 2]O[sub 5

Energy Technology Data Exchange (ETDEWEB)

Furukawa, Kikuo.; Yoshizawa, Fujiroku.; Akutsu, Yoshiaki.; Arai, Mitsuru.; Tamura, Masamitsu. (The University of Tokyo, Tokyo (Japan). School of Engineering)

1999-06-30

In order to clarify the mechanism of aromatic nitration with N[sub 2]O[sub 5], the nitration of toluene with N[sub 2]O[sub 5] in CCl[sub 4] was carried out and was investigated the yields of the products and the isomer distributions. As a result, the reaction should be very rapid and should involve a typical electrophilic substitution. Moreover, in order to investigate the effect of the solvent, the nitration of toluene with N[sub 2]O[sub 5] powder without CCl[sub 4] was also carried out. The nitration of toluene with N[sub 2]O[sub 5]/N[sub 2]O[sub 4] was also carried out, and the dependence of the isomer distribution and the ratio of produced nitrotoluenes on the ratio of N[sub 2]O[sub 5] was showed. As a result, it is suggested that N[sub 2]O[sub 5] should be dissociated homolytically in CCl[sub 4] and that the aromatic nitration with N[sub 2]O[sub 5] in CCl[sub 4] should proceed with NO[sub 3] as the initial attacking species. The thermal decomposition of N[sub 2]O[sub 5] over 25 degree C should produce a large amount of N[sub 2]O[sub 4](2NO[sub 2]), and the attack of NO[sub 2] on the intermediate [Ar(H)(ONO[sub 2])] should form the intermediates [AR(H)(ONO[sub 2])(H)(NO[sub 2])] following the specific isomer distributions. (author)
Nitration of toluene with N{sub 2}O{sub 5}

Energy Technology Data Exchange (ETDEWEB)

Furukawa, Kikuo.; Yoshizawa, Fujiroku.; Akutsu, Yoshiaki.; Arai, Mitsuru.; Tamura, Masamitsu. [The University of Tokyo, Tokyo (Japan). School of Engineering

1999-06-30

In order to clarify the mechanism of aromatic nitration with N{sub 2}O{sub 5}, the nitration of toluene with N{sub 2}O{sub 5} in CCl{sub 4} was carried out and was investigated the yields of the products and the isomer distributions. As a result, the reaction should be very rapid and should involve a typical electrophilic substitution. Moreover, in order to investigate the effect of the solvent, the nitration of toluene with N{sub 2}O{sub 5} powder without CCl{sub 4} was also carried out. The nitration of toluene with N{sub 2}O{sub 5}/N{sub 2}O{sub 4} was also carried out, and the dependence of the isomer distribution and the ratio of produced nitrotoluenes on the ratio of N{sub 2}O{sub 5} was showed. As a result, it is suggested that N{sub 2}O{sub 5} should be dissociated homolytically in CCl{sub 4} and that the aromatic nitration with N{sub 2}O{sub 5} in CCl{sub 4} should proceed with NO{sub 3} as the initial attacking species. The thermal decomposition of N{sub 2}O{sub 5} over 25 degree C should produce a large amount of N{sub 2}O{sub 4}(2NO{sub 2}), and the attack of NO{sub 2} on the intermediate [Ar(H)(ONO{sub 2})] should form the intermediates [AR(H)(ONO{sub 2})(H)(NO{sub 2})] following the specific isomer distributions. (author)
Study of a Li/polymer electrolyte/V{sub 2}O{sub 5} battery; Etude d`un accumulateur Li/POE/V{sub 2}O{sub 5}

Energy Technology Data Exchange (ETDEWEB)

Tassin, N.; Bronoel, G.; Fauvarque, J.F.; Millot, A. [Laboratoire SORAPEC, 94 - Fontenay-sous-Bois (France)

1996-12-31

The use of POE solid polymer electrolytes in negative lithium electrode batteries allows to reach energy density values close to 150 Wh/kg. The functioning of Li/POE/V{sub 2}O{sub 5} elements has been studied on small capacity elementary cells (about 26 mAh) and the results obtained were confirmed using coiled elements of 1.4 to 1.8 Ah capacity. This work has been carried out for Bollore Technologies (BT) and Electricite de France (EdF) companies. (J.S.)
Study of a Li/polymer electrolyte/V{sub 2}O{sub 5} battery; Etude d`un accumulateur Li/POE/V{sub 2}O{sub 5}

Energy Technology Data Exchange (ETDEWEB)

Tassin, N; Bronoel, G; Fauvarque, J F; Millot, A [Laboratoire SORAPEC, 94 - Fontenay-sous-Bois (France)

1997-12-31

The use of POE solid polymer electrolytes in negative lithium electrode batteries allows to reach energy density values close to 150 Wh/kg. The functioning of Li/POE/V{sub 2}O{sub 5} elements has been studied on small capacity elementary cells (about 26 mAh) and the results obtained were confirmed using coiled elements of 1.4 to 1.8 Ah capacity. This work has been carried out for Bollore Technologies (BT) and Electricite de France (EdF) companies. (J.S.)
Proxy Records of the Indonesian Low and the El Ni{tilde n}o-Southern Oscillation (ENSO) from Stable Isotope Measurements of Indonesian Reef Corals

Energy Technology Data Exchange (ETDEWEB)

Moore, M.D.

1995-12-31

The Earth`s largest atmospheric convective center is the Indonesian Low. It generates the Australasian monsoon, drives the zonal tropospheric Walker Circulation, and is implicated in the genesis of the El Nino-Southern Oscillation (ENSO). The long-term variability of the Indonesian Low is poorly characterized, yet such information is crucial for evaluating whether changes in the strength and frequency of ENSO events are a possible manifestation of global warming. Stable oxygen isotope ratios ({delta}{sup 18}O) in shallow-water reef coral skeletons track topical convective activity over hundreds of years because the input of isotopically-depleted rainwater dilutes seawater {delta}{sup 18}O. Corals also impose a temperature-dependent fractionation on {delta}{sup 18}O, but where annual rainfall is high and sea surface temperature (SST) variability is low the freshwater flux effect dominates.
Structural and optical properties of glancing angle deposited In{sub 2}O{sub 3} columnar arrays and Si/In{sub 2}O{sub 3} photodetector

Energy Technology Data Exchange (ETDEWEB)

Mondal, A.; Shougaijam, B.; Goswami, T.; Dhar, J.C.; Singh, N.K. [National Institute of Technology, Department of Electronics and Communication Engineering, Agartala (India); Choudhury, S. [North Eastern Hill University, Department of Electronics and Communication Engineering, Shillong (India); Chattopadhay, K.K. [Jadavpur University, Department of Physics, Kolkata (India)

2014-04-15

Ordered and perpendicular columnar arrays of In{sub 2}O{sub 3} were synthesized on conducting ITO electrode by a simple glancing angle deposition (GLAD) technique. The as-deposited In{sub 2}O{sub 3} columns were investigated by field emission gun-scanning electron microscope (FEG-SEM). The average length and diameter of the columns were estimated ∝400 nm and ∝100 nm, respectively. The morphology of the structure was examined by transmission electron microscopy (TEM). X-ray diffraction (XRD) analysis shows the polycrystalline nature of the sample which was verified by selective area electron diffraction (SAED) analysis. The growth mechanism and optical properties of the columns were also discussed. Optical absorption shows that In{sub 2}O{sub 3} columns have a high band to band transition at ∝3.75 eV. The ultraviolet and green emissions were obtained from the In{sub 2}O{sub 3} columnar arrays. The P-N junction was formed between In{sub 2}O{sub 3} and P-type Si substrate. The GLAD synthesized In{sub 2}O{sub 3} film exhibits low current conduction compared to In{sub 2}O{sub 3} TF. However, the Si/GLAD-In{sub 2}O{sub 3} detector shows ∝1.5 times enhanced photoresponsivity than that of Si/In{sub 2}O{sub 3} TF. (orig.)
The borosulfates K{sub 4}[BS{sub 4}O{sub 15}(OH)], Ba[B{sub 2}S{sub 3}O{sub 13}], and Gd{sub 2}[B{sub 2}S{sub 6}O{sub 24}

Energy Technology Data Exchange (ETDEWEB)

Gross, Peter; Kirchhain, Arno; Hoeppe, Henning A. [Universitaet Augsburg, Institut fuer Physik (Germany)

2016-03-18

K{sub 4}[BS{sub 4}O{sub 15}(OH)], Ba[B{sub 2}S{sub 3}O{sub 13}], and Gd{sub 2}[B{sub 2}S{sub 6}O{sub 24}] were obtained by a new synthetic approach. The strategy involves initially synthesizing the complex acid H[B(HSO{sub 4}){sub 4}] which is subsequently reacted in an open system with anhydrous chlorides of K, Ba, and Gd to the respective borosulfates and a volatile molecule (HCl). Furthermore, protonated borosulfates should be accessible by appropriate stoichiometry of the starting materials, particularly in closed systems, which inhibit deprotonation of H[B(HSO{sub 4}){sub 4}] via condensation and dehydration. This approach led to the successful synthesis of the first divalent and trivalent metal borosulfates (Ba[B{sub 2}S{sub 3}O{sub 13}] with band-silicate topology and Gd{sub 2}[B{sub 2}S{sub 6}O{sub 24}] with cyclosilicate topology) and the first hydrogen borosulfate K{sub 4}[BS{sub 4}O{sub 15}(OH)]. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Optical microcavities and enhanced electroluminescence from electroformed Al-Al{sub 2}O{sub 3}-Ag diodes

Energy Technology Data Exchange (ETDEWEB)

Hickmott, T. W. [Department of Physics, State University of New York at Albany, Albany, New York 12222 (United States)

2013-12-21

Electroluminescence (EL) and electron emission into vacuum (EM) occur when a non-destructive dielectric breakdown of Al-Al{sub 2}O{sub 3}-Ag diodes, electroforming, results in the development of a filamentary region in which current-voltage (I-V) characteristics exhibit voltage-controlled negative resistance. The temperature dependence of I-V curves, EM, and, particularly, EL of Al-Al{sub 2}O{sub 3}-Ag diodes with anodic Al{sub 2}O{sub 3} thicknesses between 12 nm and 30 nm, has been studied. Two filters, a long-pass (LP) filter with transmission of photons with energies less than 3.0 eV and a short-pass (SP) filter with photon transmission between 3.0 and 4.0 eV, have been used to characterize EL. The voltage threshold for EL with the LP filter, V{sub LP}, is ∼1.5 V. V{sub LP} is nearly independent of Al{sub 2}O{sub 3} thickness and of temperature and is 0.3–0.6 V less than the threshold voltage for EL for the SP filter, V{sub SP}. EL intensity is primarily between 1.8 and 3.0 eV when the bias voltage, V{sub S} ≲ 7 V. EL in the thinnest diodes is enhanced compared to EL in thicker diodes. For increasing V{sub S}, for diodes with the smallest Al{sub 2}O{sub 3} thicknesses, there is a maximum EL intensity, L{sub MX}, at a voltage, V{sub LMX}, followed by a decrease to a plateau. L{sub MX} and EL intensity at 4.0 V in the plateau region depend exponentially on Al{sub 2}O{sub 3} thickness. The ratio of L{sub MX} at 295 K for a diode with 12 nm of Al{sub 2}O{sub 3} to L{sub MX} for a diode with 25 nm of Al{sub 2}O{sub 3} is ∼140. The ratio of EL intensity with the LP filter to EL intensity with the SP filter, LP/SP, varies between ∼3 and ∼35; it depends on Al{sub 2}O{sub 3} thickness and V{sub S}. Enhanced EL is attributed to the increase of the spontaneous emission rate of a dipole in a non-resonant optical microcavity. EL photons interact with the Ag and Al films to create surface plasmon polaritons (SPPs) at the metal-Al{sub 2}O{sub
Effect of surfactant amount on the morphology and magnetic properties of monodisperse ZnFe{sub 2}O{sub 4} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Zhao, Haitao, E-mail: zht95711lunwen@163.com; Liu, Ruiping; Zhang, Qiang; Wang, Qiao

2016-03-15

Graphical abstract: Polyol process to monodisperse ZnFe{sub 2}O{sub 4} nanoparticles. - Highlights: • An one-step, facile and inexpensive synthetic route to monodisperse ZnFe{sub 2}O{sub 4} nanoparticles is described. • The sodium citrate stabilized ZnFe{sub 2}O{sub 4} nanoparticles with a diameter in the 5–8 nm size range can be easily dispersed in water. • The synthesis is very robust in terms of variations of experimental parameters. • ZnFe{sub 2}O{sub 4} nanoparticles present ferrimagnetic behavior at room temperature with a small hysteresis. - Abstract: The spinel ZnFe{sub 2}O{sub 4} ferrites with sodium citrate as a surfactant were fabricated by polyol process. The effect of surfactant amount on the structure, morphology and magnetic properties of ZnFe{sub 2}O{sub 4} ferrites were investigated by X-ray diffraction(XRD), transmission electron microscope (TEM), thermogravimetric and differential scanning calorimetry (TG–DSC) and vibrating sample magnetometry (VSM), respectively. The results indicate that the structure of ZnFe{sub 2}O{sub 4} ferrites is a pure cubic spinel structure with a particle size of 5–8 nm. The dispersion of the synthesized ZnFe{sub 2}O{sub 4} is enhanced when the mole ratio of Fe(acac){sub 3} to sodium citrate decreases. The synthesized particles present ferrimagnetic behavior with a small hysteresis at room temperature. The increase of surfactant amount conversely leads to the decrease in the saturation magnetization value (Ms) especially when the mole ratio of Fe(acac){sub 3} to sodium citrate decreases to 8:3. Its Ms value is drastically reduced to 18.97 emu/g.
Porous Co{sub 3}O{sub 4} nanoplatelets by self-supported formation as electrode material for lithium-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Wang Jieqiang, E-mail: mse_wangjq@ujn.edu.c [School of Materials Science and Engineering, University of Jinan, Jinan 250022 (China); Institute for Superconducting and Electronic Materials, University of Wollongong, NSW 2522 (Australia); Du Guodong; Zeng Rong [Institute for Superconducting and Electronic Materials, University of Wollongong, NSW 2522 (Australia); Niu Ben [School of Materials Science and Engineering, University of Jinan, Jinan 250022 (China); Chen Zhixin [School of Mechanical, Materials and Mechatronics, Faculty of Engineering, University of Wollongong, NSW 2522 (Australia); Guo Zaiping [School of Mechanical, Materials and Mechatronics, Faculty of Engineering, University of Wollongong, NSW 2522 (Australia); Institute for Superconducting and Electronic Materials, University of Wollongong, NSW 2522 (Australia); Dou Shixue [Institute for Superconducting and Electronic Materials, University of Wollongong, NSW 2522 (Australia)

2010-06-30

In this paper, we have reported a simple and rapid approach for the large-scale synthesis of beta-Co(OH){sub 2} nanoplatelets via the microwave hydrothermal process using potassium hydroxide as mineralizer at 140 deg. C for 3 h. Calcining the beta-Co(OH){sub 2} nanoplatelets at 350 deg. C for 2 h, porous Co{sub 3}O{sub 4} nanoplatelets with a 3D quasi-single-crystal framework were obtained. The process of converting the beta-Co(OH){sub 2} nanoplatelets into the Co{sub 3}O{sub 4} nanoplatelets is a self-supported topotactic transformation, which is easily controlled by varying the calcining temperature. The textural characteristics of Co{sub 3}O{sub 4} products have strong positive effects on their electrochemical properties as electrode materials in lithium-ion batteries. The obtained porous Co{sub 3}O{sub 4} nanoplatelets exhibit a low initial irreversible loss (18.1%), ultrahigh capacity, and excellent cyclability. For example, a reversible capacity of 900 mAh g{sup -1} can be maintained after 100 cycles.
Performance test of PSA-type O{sub 2} separator for efficient O{sub 2} supply to room ventilation system combined with CO{sub 2} adsorption module

Energy Technology Data Exchange (ETDEWEB)

Han, Gi Bo; Jang, Jung Hee; Choi, Changsik [Institute for Advanced Engineering, Yongin (Korea, Republic of); Lee, Tae Jin [School of Chemical Engineering Yeungnam University, Gyeongsan (Korea, Republic of)

2016-04-15

High purity O{sub 2} concentrated by the PSA-type O{sub 2} separator was applied to a room ventilation system combined with CO{sub 2} adsorption module to remove the indoor CO{sub 2} for the indoor air quality. And then the room was occupied by several persons to breathe for the O{sub 2} consumption and CO{sub 2} generation. As a result, the indoor air quality was improved by the ventilation system combined with the O{sub 2} supply and the CO{sub 2} adsorption module. It was due to the fact that the CO{sub 2} concentration was not steeply increased, but also even decreased and then the increasing rate of the O{sub 2} concentration with the O{sub 2} supply was simultaneously increased by the CO{sub 2} removal despite the CO{sub 2} generation and O{sub 2} consumption with the four persons' breathing. As a representative result, in the case of supplying the high purity O{sub 2} of 30 L/min under using the CO{sub 2} adsorption module, the best performance with the highest increasing rate of O{sub 2} concentration and the lowest increasing rate of CO{sub 2} concentration was obtained among the various cases, and then the increasing rates of CO{sub 2} radiation and O{sub 2} concentration were -2.3 ppm/min and 33.3%/min, respectively.
Nitration of benzene with N{sub 2}O{sub 5}

Energy Technology Data Exchange (ETDEWEB)

Furukawa, Kikuo; Yoshizawa, FUjiroku; Akutsu, Yoshiaki; Arai, Mitsuru; Tamura, Masamitsu [The University of Tokyo, Tokyo (Japan). School of Engineering

1999-08-31

In order to clarify the mechanism of aromatic nitration with N{sub 2}O{sub 5}, the nitrations of benzene and of nitrobenzene with N{sub 2}O{sub 5} were carried out and the yield of the products and the isomer distribution of dinitrobenzenes were investigated. As a result, the isomer distribution of the dinitrobenzenes in the nitration of benzene was quite different from that in the nitration of nitrobenzene. Moreover, the ratio of [dinitrobenzenes]/[nitrobenzene] increased with the reaction temperature. The nitration of benzene with N{sub 2}O{sub 5}/N{sub 2}O{sub 4} was also carried out and showed the dependence of the ratio of [dinitrobenzenes]/[nitrobenzene] on the ratio of N{sub 2}O{sub 4}. As a result, it is suggested that N{sub 2}O{sub 5} should be dissociated homolytically in CCl{sub 4}, that the aromatic nitration with N{sub 2}O{sub 5} over 25 degree C should produce a large amount of N{sub 2}O{sub 4}(2NO{sub 2}) and the attack of NO{sub 2} on the intermediate [Ar(H)(ONO{sub 2})] should form the intermediates [Ar(H)(ONO{sub 2})(H)(NO{sub 2})] following the production of a large amount of dinitrobenzenes. (author)
Compressive strain-dependent bending strength property of Al{sub 2}O{sub 3}-ZrO{sub 2} (1.5 mol% Y{sub 2}O{sub 3}) composites performance by HIP

Energy Technology Data Exchange (ETDEWEB)

Reyes-Rojas, A. [Centro de Investigacion en Materiales Avanzados S.C. (CIMAV), Miguel de Cervantes 120, Complejo Industrial Chihuahua, Cd. de Chihuahua, Chihuahua (Mexico)], E-mail: armando_reyesmx@yahoo.com.mx; Esparza-Ponce, H. [Centro de Investigacion en Materiales Avanzados S.C. (CIMAV), Miguel de Cervantes 120, Complejo Industrial Chihuahua, Cd. de Chihuahua, Chihuahua (Mexico); De la Torre, S.D. [Centro de Investigacion e Innovacion Tecnologica (CIITEC)-IPN, D.F. Mexico (Mexico); Torres-Moye, E. [Centro de Investigacion en Materiales Avanzados S.C. (CIMAV), Miguel de Cervantes 120, Complejo Industrial Chihuahua, Cd. de Chihuahua, Chihuahua (Mexico)

2009-04-15

Nanometric powders and sintered ceramics of Al{sub 2}O{sub 3}-ZrO{sub 2} (1.5 mol% Y{sub 2}O{sub 3}) prepared by hot isostatic pressing HIP have been studied. A detailed crystallographic study has been performed through X-ray diffraction, Williamson-Hall method, Rietveld method and high-resolution electron microscopy HREM analysis. The crystallographic structure data, such as domain size, lattice parameters, wt% phase, and micro-strain direction have been obtained using Rietveld refinement and Williamson-Hall methods. The results revealed that the compressive strain ({epsilon}) increased from 0.56 to 1.18 (10{sup -3}) as the t-ZrO{sub 2} content increased too. The HREM interface study conducted along the [0 0 0 1]Al{sub 2}O{sub 3}||[0 0 1]ZrO{sub 2} zone axis revealed a micro-strain lattice distortion accumulated at the grain boundary due to the ZrO{sub 2} martensitic phase transformation on cooling, t-ZrO{sub 2} grains coalescence and to the grain growth of {alpha}-Al{sub 2}O{sub 3} which cause elongated tetragonal crystals. Micro-strain lattice distortion is adjusted by the shear displacements of the planes (1 1 0) and (11-bar0) along [1-bar10] and [1-bar1-bar0] crystallographic directions, respectively; these planes are arrested by the (101-bar0) alumina plane. In this case, semi-coherent interfaces were observed along the grain boundary. It is verified that the bending strength increased in connection with the strain accumulation and amount of tetragonal structure.
PLASS: Protein-ligand affinity statistical score a knowledge-based force-field model of interaction derived from the PDB

Science.gov (United States)

Ozrin, V. D.; Subbotin, M. V.; Nikitin, S. M.

2004-04-01

We have developed PLASS (Protein-Ligand Affinity Statistical Score), a pair-wise potential of mean-force for rapid estimation of the binding affinity of a ligand molecule to a protein active site. This scoring function is derived from the frequency of occurrence of atom-type pairs in crystallographic complexes taken from the Protein Data Bank (PDB). Statistical distributions are converted into distance-dependent contributions to the Gibbs free interaction energy for 10 atomic types using the Boltzmann hypothesis, with only one adjustable parameter. For a representative set of 72 protein-ligand structures, PLASS scores correlate well with the experimentally measured dissociation constants: a correlation coefficient R of 0.82 and RMS error of 2.0 kcal/mol. Such high accuracy results from our novel treatment of the volume correction term, which takes into account the inhomogeneous properties of the protein-ligand complexes. PLASS is able to rank reliably the affinity of complexes which have as much diversity as in the PDB.
Degradation kinetics and mechanism of β-lactam antibiotics by the activation of H{sub 2}O{sub 2} and Na{sub 2}S{sub 2}O{sub 8} under UV-254 nm irradiation

Energy Technology Data Exchange (ETDEWEB)

He, Xuexiang [Environmental Engineering and Science Program, University of Cincinnati, Cincinnati, OH 45221-0012 (United States); Department of Civil and Environmental Engineering and Nireas-International Water Research Centre, School of Engineering, University of Cyprus, PO Box 20537, 1678 Nicosia (Cyprus); Mezyk, Stephen P. [Department of Chemistry and Biochemistry, California State University Long Beach, 1250 Bellflower Blvd., Long Beach, CA 90840 (United States); Michael, Irene; Fatta-Kassinos, Despo [Department of Civil and Environmental Engineering and Nireas-International Water Research Centre, School of Engineering, University of Cyprus, PO Box 20537, 1678 Nicosia (Cyprus); Dionysiou, Dionysios D., E-mail: dionysios.d.dionysiou@uc.edu [Environmental Engineering and Science Program, University of Cincinnati, Cincinnati, OH 45221-0012 (United States); Department of Civil and Environmental Engineering and Nireas-International Water Research Centre, School of Engineering, University of Cyprus, PO Box 20537, 1678 Nicosia (Cyprus)

2014-08-30

Graphical abstract: - Highlights: • Removal efficiency was comparable at different UV fluence rates but same fluence. • Reducing pH to 3 or 2 did not inhibit the removal of nitrobenzene by UV/S{sub 2}O{sub 8}{sup 2−}. • 1.84 × 10{sup −14} M [HO{sup •} ]{sub ss} and 3.10 × 10{sup −13} M [SO{sub 4}{sup •} {sup −}]{sub ss} in UV/S{sub 2}O{sub 8}{sup 2−} were estimated. • HO{sup •} reacted faster with the β-lactams than SO{sub 4}{sup •} {sup −} but sharing similar byproducts. • Transformation pathways included hydroxylation, hydrolysis and decarboxylation. - Abstract: The extensive production and usage of antibiotics have led to an increasing occurrence of antibiotic residuals in various aquatic compartments, presenting a significant threat to both ecosystem and human health. This study investigated the degradation of selected β-lactam antibiotics (penicillins: ampicillin, penicillin V, and piperacillin; cephalosporin: cephalothin) by UV-254 nm activated H{sub 2}O{sub 2} and S{sub 2}O{sub 8}{sup 2−} photochemical processes. The UV irradiation alone resulted in various degrees of direct photolysis of the antibiotics; while the addition of the oxidants improved significantly the removal efficiency. The steady-state radical concentrations were estimated, revealing a non-negligible contribution of hydroxyl radicals in the UV/S{sub 2}O{sub 8}{sup 2−} system. Mineralization of the β-lactams could be achieved at high UV fluence, with a slow formation of SO{sub 4}{sup 2−} and a much lower elimination of total organic carbon (TOC). The transformation mechanisms were also investigated showing the main reaction pathways of hydroxylation (+16 Da) at the aromatic ring and/or the sulfur atom, hydrolysis (+18 Da) at the β-lactam ring and decarboxylation (–44 Da) for the three penicillins. Oxidation of amine group was also observed for ampicillin. This study suggests that UV/H{sub 2}O{sub 2} and UV/S{sub 2}O{sub 8}{sup 2−} advanced
Growth and {delta}{sup 13}C responses to increasing atmospheric carbon dioxide concentrations for several crop species

Energy Technology Data Exchange (ETDEWEB)

Hanba, Y.T.; Wada, E. [Center for Ecological Research, Kyoto University, Kyoto (Japan); Osaki, M.; Nakamura, T. [Faculty of Agriculture, Hokkaido University, Hokkaido (Japan)

1996-04-01

The responses of plant growth and carbon isotope discrimination ({Delta}) to elevated atmospheric CO{sub 2} concentrations for several crop species (lettuce: Lactuca sativa L.; corn: Zea Mays L. var. P3540, wheat: Triticum aestivum L. var Haruyutaka; and soybean: Glycine Max (L). Merr. var. Kitamusume) were investigated. Shoot relative growth rate was used to indicate plant growth, and {delta}{sup 13}C value of leaf materials in corn (C4 species) was used to calculate {Delta} for C3 species. Plant growth was stimulated by enriched CO{sub 2}, while {Delta} remained almost constant as CO{sub 2} concentration changed. {Delta} showed interspecific difference, and the plant species of larger {Delta} had larger relative growth rates. Relative growth rates of the plants of larger {Delta} were stimulated by CO{sub 2} enrichment more than those of the plants of smaller {Delta}. We propose that plant {Delta} could be a possible parameter to assess the interspecific difference of plant response to the increasing atmospheric CO{sub 2} concentrations. 3 figs., 2 tabs., 25 refs.
Interactions of a La{sub O.9}Sr{sub O.1}Ga{sub O.8}Mg{sub O.2}O{sub 3-{delta}} electrolyte with Fe{sub 2}O{sub 3}, Co{sub 2}O{sub 3} and NiO anode materials

Energy Technology Data Exchange (ETDEWEB)

Zhang, X.; Ohara, S.; Okawa, H.; Maric, R.; Fukui, T. [Japan Fine Ceramics Center, 2-4-1 Mutsuo, Atsuta-ku, 456-8587 Nagoya (Japan)

2001-01-02

In this study, the interactions of a Sr- and Mg-doped lanthanum gallate (LSGM with composition La{sub O.9}Sr{sub O.1}Ga{sub O.8}Mg{sub O.2}O{sub 3-{delta}}) electrolyte with Fe{sub 2}O{sub 3}, Co{sub 2}O{sub 3} and NiO as the anode starting materials were investigated. It was found that the order of reactivity of the LSGM with the three oxides was Co{sub 2}O{sub 3}>NiO>Fe{sub 2}O{sub 3}, and La-containing oxides were detected in these binary powder mixtures after firing. The anode performance was greatly influenced by the interaction. The Fe{sub 2}O{sub 3}-LSGM anode, mixed with 40 vol.% LSGM powder and sintered at 1150C, exhibited the highest initial performance in comparison with NiO-LSGM and Co{sub 2}O{sub 3}-LSGM anodes. It seems that Fe{sub 2}O{sub 3} is a possible anode starting material for a LSGM-based solid oxide fuel cell.
Photoluminescence in Pb{sup 2+} activated SrB{sub 4}O{sub 7} and SrB{sub 2}O{sub 4} phosphors

Energy Technology Data Exchange (ETDEWEB)

Gawande, A.B., E-mail: gawandeab@gmail.com [Department of Physics, SGB Amravati University, Amravati-444602, Maharashtra (India); Ingle, J.T. [J. D. Institute of Engineering and Technology, Yavatmal, Maharashtra (India); Sonekar, R.P., E-mail: sonekar_rp@yahoo.com [Department of Physics, G.S. College, Khamgaon District, Buldhana, Maharashtra (India); Omanwar, S.K. [Department of Physics, SGB Amravati University, Amravati-444602, Maharashtra (India)

2014-05-01

The powder samples of SrB{sub 4}O{sub 7}:Pb{sup 2+} and SrB{sub 2}O{sub 4}:Pb{sup 2+} were prepared by solution combustion synthesis method. The synthesis is based on the exothermic reaction between the fuel (Urea) and Oxidizer (Ammonium nitrate). The synthesized materials were characterized using TG–DTA, powder XRD, SEM and the photoluminescence properties were studied using a Hitachi F-7000 spectrophotometer at room temperature. Both the samples SrB{sub 4}O{sub 7}:Pb{sup 2+} and SrB{sub 2}O{sub 4}:Pb{sup 2+} show broad emission of Pb{sup 2+} respectively at 307 nm and 360 nm (corresponds to {sup 3}P{sub 1} to {sup 1}S{sub 0} transition). The optimum concentrations of Pb{sup 2+} in both the phosphors SrB{sub 4}O{sub 7}:Pb{sup 2+} and SrB{sub 2}O{sub 4}:Pb{sup 2+} were found to be 3 mol% (relative to Sr) and for this concentration the critical transfer distance R{sub 0} were calculated to be 10.21 Å and 12.22 Å respectively. The Stokes shifts were calculated to be respectively 4464 cm{sup −1} and 8454 cm{sup −1}. The emission bands of both the phosphors are in the UV region and the phosphors can be potential candidates for application in UV lamps. - Highlights: • SrB{sub 4}O{sub 7}:Pb{sup 2+} and SrB{sub 2}O{sub 4}:Pb{sup 2+} have been synthesized by Novel solution combustion synthesis technique. • The synthesized materials were characterized using TG–DTA, powder XRD and SEM. • Photoluminescence spectra of synthesized materials showed the characteristic transition in Pb{sup 2+}. • Stokes shift, optimum concentration and critical transfer distance R{sub 0} were determined.

Controllable synthesis and field emission enhancement of Al{sub 2}O{sub 3} coated In{sub 2}O{sub 3} core-shell nanostructures

Energy Technology Data Exchange (ETDEWEB)

Wang Yang; Li Yawei; Yu Ke; Zhu Ziqiang, E-mail: yk5188@263.net [Key Laboratory of Polar Materials and Devices (Ministry of Education of China), Department of Electronic Engineering, East China Normal University, Shanghai 200241 (China)

2011-03-16

Four types of indium oxide (In{sub 2}O{sub 3}) nanostructures were synthesized on Au-catalysed silicon substrate via a VLS method. A rod-like In{sub 2}O{sub 3} nanostructure was chosen to fabricate In{sub 2}O{sub 3}-Al{sub 2}O{sub 3} core-shell nanostructures with different shell thicknesses via a two-step method. Core-shell nanostructures with shell thickness of 30 nm are reprocessed by annealing and H{sub 2} plasma treating. Field emission (FE) properties of all the samples were measured and compared. It is found that Al{sub 2}O{sub 3} coatings remarkably decrease the effective work function and improve the FE capabilities of In{sub 2}O{sub 3} nanostructures (turn-on field decreases from 1.34 to 1.26 V {mu}m{sup -1}, threshold field decreases from 3.60 to 2.64 V {mu}m{sup -1}). Annealing and H{sub 2} plasma treating can promote the improvement even further (turn-on field 1.23 V {mu}m{sup -1}, 1.21 V {mu}m{sup -1} and threshold field 2.50 V {mu}m{sup -1}, 2.14 V {mu}m{sup -1}, respectively). The FE enhancement is attributed to the electron accumulation in the insulating Al{sub 2}O{sub 3} nanostructure and the electron redistribution at the heterojunction.
Evidence of superoxide radical contribution to demineralization of sulfamethoxazole by visible-light-driven Bi{sub 2}O{sub 3}/Bi{sub 2}O{sub 2}CO{sub 3}/Sr{sub 6}Bi{sub 2}O{sub 9} photocatalyst

Energy Technology Data Exchange (ETDEWEB)

Ding, Shiyuan; Niu, Junfeng, E-mail: junfengn@bnu.edu.cn; Bao, Yueping; Hu, Lijuan

2013-11-15

Highlights: • Bi{sub 2}O{sub 3}/Bi{sub 2}O{sub 2}CO{sub 3}/Sr{sub 6}Bi{sub 2}O{sub 9} can degrade SMX efficiently using visible light. • 36% of TOC reduction was achieved after 120 min treatment. • The main mineralization products were confirmed. • Formation of O{sub 2}·{sup −} was evidenced by using ESR and a chemiluminescent probe. -- Abstract: Photocatalytic degradation of sulfamethoxazole (SMX) was investigated using Bi{sub 2}O{sub 3}/Bi{sub 2}O{sub 2}CO{sub 3}/Sr{sub 6}Bi{sub 2}O{sub 9} (BSO) photocatalyst under visible light (>420 nm) irradiation. The photochemical degradation of SMX followed pseudo-first-order kinetics. The reaction kinetics was determined as a function of initial SMX concentrations (5–20 mg L{sup −1}), initial pH (3–11) and BSO concentrations (6–600 mg L{sup −1}). Approximately, 90% of SMX (10 mg L{sup −1}) degradation and 36% of TOC reduction were achieved at pH 7.0 after 120 min irradiation. The main mineralization products, including NH{sub 4}{sup +}, NO{sub 3}{sup −}, SO{sub 4}{sup 2−} and CO{sub 2}, as well as intermediates 3-amino-5-methylisoxazole (AMI), p-benzoquinone (BZQ), and sulfanilic acid (SNA) were detected in aqueous solution. The formation of O{sub 2}·{sup −} radical was evidenced by using electron spin resonance and a chemiluminescent probe, luminal. A possible degradation mechanism involving excitation of BSO, followed by charge injection into the BSO conduction band and formation of reactive superoxide radical (O{sub 2}·{sup −}) was proposed for the mineralization of SMX. During the reaction, the O{sub 2}·{sup −} radical attacks the sulfone moiety and causes the cleavage of the S-N bond, which leads to the formation of two sub-structure analogs, AMI and SNA.
Rapid extraction of uranium from sea water using Fe{sub 3}O{sub 4} and humic acid coated Fe{sub 3}O{sub 4} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Singhal, Pallavi, E-mail: psinghal@barc.gov.in [Homi Bhabha National Institute, Mumbai 400094 (India); Health Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Jha, Sanjay K. [Homi Bhabha National Institute, Mumbai 400094 (India); Health Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Pandey, Shailaja P. [Analytical Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Neogy, Suman [Mechanical Metallurgy Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

2017-08-05

Highlights: • Uranium extraction using Fe{sub 3}O{sub 4} and HA coated Fe{sub 3}O{sub 4} NPs has been demonstrated. • Result indicates uranium extraction from both water and sea water matrix. • With increase in HA coating uranium extraction increases. • Fe{sub 3}O{sub 4}/HA 1 is the best material among synthesized one for uranium extraction. - Abstract: Uranium is one of the most toxic elements present in the environment and a number of methods have been developed for its extraction. Herein we have demonstrated a new method using magnetic nanoparticles (NPs) that can be used for uranium extraction from water and sea water matrix. Fe{sub 3}O{sub 4} and humic acid (HA) coated Fe{sub 3}O{sub 4} NPs with different amount of HA coating were synthesized and uranium sorption from water and sea water matrix was demonstrated. It was observed that sorption increases with increase in amount of HA coating. NPs settlement in presence of magnetic field was monitored where only bare Fe{sub 3}O{sub 4} and Fe{sub 3}O{sub 4}/HA 1 NPs settles while no settlement was observed for Fe{sub 3}O{sub 4}/HA 2 and Fe{sub 3}O{sub 4}/HA 3 NPs. Considering both sorption and particle separation from the matrix Fe{sub 3}O{sub 4}/HA 1 NPs are the best among synthesized ones with maximum sorption capacity of 10.5 mg of U/g of NPs. The results presented here reveal the exceptional potential of magnetic NPs and functionalized magnetic NPs for environmental remediation of uranium and to extract uranium from sea water on which to the best of our knowledge no report is available till now.
One-pot synthesis of porphyrin functionalized γ-Fe{sub 2}O{sub 3} nanocomposites as peroxidase mimics for H{sub 2}O{sub 2} and glucose detection

Energy Technology Data Exchange (ETDEWEB)

Liu, Qingyun, E-mail: qyliu@sdust.edu.cn; Zhang, Leyou; Li, Hui; Jia, Qingyan; Jiang, Yanling; Yang, Yanting; Zhu, Renren

2015-10-01

Meso-tetrakis(4-carboxyphenyl)-porphyrin-functionalized γ-Fe{sub 2}O{sub 3} nanoparticles (H{sub 2}TCPP-γ-Fe{sub 2}O{sub 3}) were successfully prepared by one-pot method under hydrothermal conditions and were found to possess intrinsic peroxidase-like activity. The H{sub 2}TCPP-γ-Fe{sub 2}O{sub 3} nanocomposites can catalytically oxidize peroxidase substrate 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H{sub 2}O{sub 2} to produce a blue color reaction, which can be easily observed by the naked eye. Furthermore, kinetic studies indicate that the H{sub 2}TCPP-γ-Fe{sub 2}O{sub 3} nanocomposites have an even higher affinity to TMB than that of the natural enzyme, horseradish peroxidase (HRP). On the basis of the high activity, the reaction provides a simple, sensitive and selective method for colorimetric detection of H{sub 2}O{sub 2} over a range of 10–100 μM with a minimum detection limit of 1.73 μM. Moreover, H{sub 2}TCPP-γ-Fe{sub 2}O{sub 3}/glucose oxidase (GOx)/TMB system provides a novel colorimetric sensor for glucose and shows good response toward glucose detection over a range of 5–25 μM with a minimum detection limit of 2.54 μM. The results indicated that it is a simple, cheap, convenient, highly selective, sensitive and easy handling colorimetric assay. Results of a fluorescent probe suggest that the catalase-mimic activity of the H{sub 2}TCPP-γ-Fe{sub 2}O{sub 3} nanocomposites effectively catalyze the decomposition of H{sub 2}O{sub 2} into H{sub 2}O and O{sub 2}. - Graphical abstract: 5,10,15,20-Tetrakis(4-carboxyl phenyl)-porphyrin (H{sub 2}TCPP)-γ-Fe{sub 2}O{sub 3} nanocomposites were demonstrated to possess intrinsic peroxidase-like activity and showed a higher catalytic activity, compared to that of γ-Fe{sub 2}O{sub 3} nanoparticles alone. - Highlights: • Porphyrin-functionalized γ-Fe{sub 2}O{sub 3} nanoparticles were prepared by one-pot method. • The porphyrin-γ-Fe{sub 2}O{sub 3} nanocomposites were found to possess
Combustion synthesis of LiMn{sub 2}O{sub 4} with citric acid and the effect of post-heat treatment

Energy Technology Data Exchange (ETDEWEB)

Han, Y.S. [Korea Advanced Istitute of Science and Technology, Taejeon (Korea); Son, J.T. [Dong-A Electric Equipment Co. LTD., Seoul (Korea); Kim, H.G. [Korea Advanced Istitute of Science and Technology, Taejeon (Korea); Jung, H.T. [Dongshin University, Chonnam (Korea)

2001-04-01

Combustion process with citrate was used to produce the LiMn{sub 2}O{sub 4} powder. Precursors are pre-ignited in open air followed by post-heating in the range from 600 deg. C to 800 deg. C for 4 h. With varying the molar ration (R) of ethylene glycol (EG) to citric acid (CA) from 0 to 4, the effect of EG content on powder characteristics is evaluated. Vacuum drying promote the auto-ignition at room temperature. With small addition of EG metal ion was selectively segregated with organic substances and undesired lithium evaporation occurred during post-heating. LiMn {sub 2}O{sub 4} phase which is produced by combustion reaction was decomposed back to Mn {sub 3}O{sub 4} because the reaction temperature was higher than 950 deg. C. With increasing EG content, the homogeneity of LiMn {sub 2}O{sub 4} powder increased and specific surface area increased. And lithium evaporation during vacuum drying and/or ignition also increased. (author). 18 refs., 1 tab., 11 figs.
Synthesis and magnetic properties of hard magnetic (CoFe{sub 2}O{sub 4})-soft magnetic (Fe{sub 3}O{sub 4}) nano-composite ceramics by SPS technology

Energy Technology Data Exchange (ETDEWEB)

Fei Chunlong [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Hubei Key Laboratory on Organic and Polymeric Opto-electronic Materials, Wuhan University, Wuhan 430072 (China); Zhang Yue [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Hubei Key Laboratory on Organic and Polymeric Opto-electronic Materials, Wuhan University, Wuhan 430072 (China); Key Laboratory for the Green Preparation and Application of Functional Materials of Ministry of Education, Hubei University, Wuhan 430062 (China); Yang Zhi; Liu Yong [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Hubei Key Laboratory on Organic and Polymeric Opto-electronic Materials, Wuhan University, Wuhan 430072 (China); Xiong Rui, E-mail: wudawujiron@163.co [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Hubei Key Laboratory on Organic and Polymeric Opto-electronic Materials, Wuhan University, Wuhan 430072 (China) and Key Laboratory for the Green Preparation and Application of Functional Materials of Ministry of Education, Hubei University, Wuhan 430062 (China); Shi Jing [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Hubei Key Laboratory on Organic and Polymeric Opto-electronic Materials, Wuhan University, Wuhan 430072 (China); International Center for Materials Physics, Shen Yang 110015 (China); Ruan Xuefeng [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Hubei Key Laboratory on Organic and Polymeric Opto-electronic Materials, Wuhan University, Wuhan 430072 (China)

2011-07-15

CoFe{sub 2}O{sub 4}/Fe{sub 3}O{sub 4} nano-composite ceramics were synthesized by Spark Plasma Sintering. The X-ray diffraction patterns show that all samples are composed of CoFe{sub 2}O{sub 4} and Fe{sub 3}O{sub 4} phases when the sintering temperature is below 900 {sup o}C. It is found that the magnetic properties strongly depend on the sintering temperature. The two-step hysteresis loops for samples sintered below 500 {sup o}C are observed, but when sintering temperature reaches 500 {sup o}C, the step disappears, which indicates that the CoFe{sub 2}O{sub 4} and Fe{sub 3}O{sub 4} are well exchange coupled. As the sintering temperature increases from 500 to 800 {sup o}C, the results of X-ray diffractometer indicate the constriction of crystalline regions due to the ion diffusion at the interfaces of CoFe{sub 2}O{sub 4}/Fe{sub 3}O{sub 4} phases, which have great impact on the magnetic properties. - Research highlights: In this work, a series of CoFe{sub 2}O{sub 4}/Fe{sub 3}O{sub 4} nano-composite ceramics were prepared through SPS. The magnetic properties of these ceramics have been studied in detail. It is found that the magnetic properties strongly depend on the sintering temperature.
Sintering of SiC ceramics, via liquid phase, with Al{sub 2}O{sub 3}-Yb{sub 2}O{sub 3} additives; Sinterizacao de ceramicas de SiC, via fase liquida, com aditivos de Al{sub 2}O{sub 3}-Yb{sub 2}O{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Atilio, I.; Oliveira, M.R.; Garcia, G.C.R.; Ribeiro, S., E-mail: isabelaatilio@hotmail.com [Universidade de Sao Paulo (USP/EEL), Lorena, SP (Brazil). Escola de Engenharia. Dept. de Engenharia de Materiais

2012-07-01

The objective of this work was to study the sintering of SiC, through liquid phase, using the additive system Al{sub 2}O{sub 3} and Yb{sub 2}O{sub 3} for the first time. The samples were sintered at temperatures of 1900, 1950 and 2000 deg C for 60 minutes. The melting point of the system was determined according to DIN 51730. It has been found the ability of wetting of SiC in the system. The densification results were: 86,36% at 1900 deg C, 88,25% at 1950 deg C and 82,09% at 2000 deg C. The average linear shrinkage was approximately 17%. There was a conversion of β-SiC in α-SiC at all temperatures and sintering phase formation Yb{sub 3}Al{sub 5}O{sub 12}. The melting temperature was 1850 deg C for de system, consistent with the value in the phase diagram, and the wetting angle of 20 deg. The system (Yb{sub 2}O{sub 3}-Al{sub 2}O{sub 3}) is promising to make liquid phase sintering of SiC, for presenting a good result of wettability. (author)
Synthesis, surface group modification of 3D MnV{sub 2}O{sub 6} nanostructures and adsorption effect on Rhodamine B

Energy Technology Data Exchange (ETDEWEB)

Zhang, Wanqun, E-mail: wqz@ustc.edu.cn [Hefei National Laboratory for Physical Sciences at Micro-scale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Chemical Experimental Teaching Center, University of Science and Technology of China, Hefei, Anhui 230026 (China); Shi, Lei, E-mail: shil@ustc.edu.cn [Hefei National Laboratory for Physical Sciences at Micro-scale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Tang, Kaibin; Liu, Zhongping [Hefei National Laboratory for Physical Sciences at Micro-scale, University of Science and Technology of China, Hefei, Anhui 230026 (China)

2012-07-15

Highlights: ► Fabrication of urchin-like MnV{sub 2}O{sub 6} with oxygen-containing surface groups. ► Mn{sub 0.5}V{sub 2}O{sub 5}·nH{sub 2}O as an intermediate product holds the key to the final products. ► 3D architectures of MnV{sub 2}O{sub 6} with oxygen-containing surface groups as sorbent. ► The sorbent shows a good adsorption ability. -- Abstract: Highly uniform 3D MnV{sub 2}O{sub 6} nanostructures modified by oxygen functional groups (-COO-) were successfully prepared in large quantities by an approach involving preparation of vanadyl ethylene glycolate as the precursor. The growth and self-assembly of MnV{sub 2}O{sub 6} nanobelts and nanorods could be readily tuned by additive species and quantities, which brought different morphologies and sizes to the final products. With a focus on the regulation of structure, the formation process of 3D architectures of MnV{sub 2}O{sub 6} by self-assembly of nanobelts was followed by field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). The consecutive processes of vanadyl ethylene glycolate and benzoyl peroxide assisted formation of layered structure Mn{sub 0.5}V{sub 2}O{sub 5}·nH{sub 2}O, growth of aligned MnV{sub 2}O{sub 6} nanobelts, and oriented assembly were proposed for the growth mechanism. The band gap vs. different morphology was also studied. Optical characterization of these MnV{sub 2}O{sub 6} with different morphologies showed direct bandgap energies at 1.8–1.95 eV. The adsorption properties of 3D MnV{sub 2}O{sub 6} nanostructures synthesized under different conditions were investigated through the removal test of Rhodamine B in aqueous water, and the 3D nanostructures synthesized with 30 g L{sup −1} benzoyl peroxide showed good adsorption capability of Rhodamine B.
Comparative study of nano-sized particles CoFe{sub 2}O{sub 4} effects on superconducting properties of Y-123 and Y-358

Energy Technology Data Exchange (ETDEWEB)

Slimani, Y.; Hannachi, E.; Ben Salem, M.K.; Hamrita, A. [Laboratory of Physics of Materials-Structures and Properties, Department of Physics, Faculty of Sciences of Bizerte, University of Carthage, 7021 Zarzouna (Tunisia); Varilci, A. [Faculty of Arts and Sciences, Department of Physics, Abant Izzet Baysal University, 14280 Bolu (Turkey); Dachraoui, W. [CINaM-CNRS, Luminy Campus, 13288 Marseille (France); Ben Salem, M., E-mail: salemwiem2005@yahoo.fr [Laboratory of Physics of Materials-Structures and Properties, Department of Physics, Faculty of Sciences of Bizerte, University of Carthage, 7021 Zarzouna (Tunisia); Ben Azzouz, F. [Laboratory of Physics of Materials-Structures and Properties, Department of Physics, Faculty of Sciences of Bizerte, University of Carthage, 7021 Zarzouna (Tunisia); College of Sciences-Girls, Department of Physics, University of Dammam (Saudi Arabia)

2014-10-01

The effects of nano-sized CoFe{sub 2}O{sub 4} particles (10 nm) addition on the structural and the normal state resistivity of YBa{sub 2}Cu{sub 3}O{sub 7} (noted Y-123) and Y{sub 3}Ba{sub 5}Cu{sub 8}O{sub 18} (noted Y-358) polycrystalline were systematically studied. Samples were synthesized in oxygen atmosphere using a standard solid state reaction technique by adding CoFe{sub 2}O{sub 4} up to 2 wt%. Phases, microstructure and superconductivity have been systematically investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrical measurements ρ(T). XRD results reveal that the lattice parameters change for both Y-123 and Y-358 phases. SEM observations reveal that the grain size is reduced with increasing the content of CoFe{sub 2}O{sub 4}. The measurements for the resistivity dependence of temperature show that the depression in superconducting temperature is more pronounced for CoFe{sub 2}O{sub 4} addition in Y-358 compound than in Y-123 one. These results may be attributed to the existence of much more disorder due to a greater number of Cu sites to be substituted by Fe and Co in Y-358 compared to Y-123.
Comparative study of water reactivity with Mo{sub 2}O{sub y}{sup −} and W{sub 2}O{sub y}{sup −} clusters: A combined experimental and theoretical investigation

Energy Technology Data Exchange (ETDEWEB)

Ray, Manisha; Waller, Sarah E.; Saha, Arjun; Raghavachari, Krishnan; Jarrold, Caroline Chick, E-mail: cjarrold@indiana.edu [Department of Chemistry, Indiana University, Bloomington, Indiana 47405 (United States)

2014-09-14

A computational investigation of the Mo{sub 2}O{sub y}{sup −} + H{sub 2}O (y = 4, 5) reactions as well as a photoelectron spectroscopic probe of the deuterated Mo{sub 2}O{sub 6}D{sub 2}{sup −} product have been carried out to understand a puzzling question from a previous study: Why is the rate constant determined for the Mo{sub 2}O{sub 5}{sup −} + H{sub 2}O/D{sub 2}O reaction, the terminal reaction in the sequential oxidation of Mo{sub 2}O{sub y}{sup −} by water, higher than the W{sub 2}O{sub 5}{sup −} + H{sub 2}O/D{sub 2}O reaction? This disparity was intriguing because W{sub 3}O{sub y}{sup −} clusters were found to be more reactive toward water than their Mo{sub 3}O{sub y}{sup −} analogs. A comparison of molecular structures reveals that the lowest energy structure of Mo{sub 2}O{sub 5}{sup −} provides a less hindered water addition site than the W{sub 2}O{sub 5}{sup −} ground state structure. Several modes of water addition to the most stable molecular and electronic structures of Mo{sub 2}O{sub 4}{sup −} and Mo{sub 2}O{sub 5}{sup −} were explored computationally. The various modes are discussed and compared with previous computational studies on W{sub 2}O{sub y}{sup −} + H{sub 2}O reactions. Calculated free energy reaction profiles show lower barriers for the initial Mo{sub 2}O{sub y}{sup −} + H{sub 2}O addition, consistent with the higher observed rate constant. The terminal Mo{sub 2}O{sub y}{sup −} sequential oxidation product predicted computationally was verified by the anion photoelectron spectrum of Mo{sub 2}O{sub 6}D{sub 2}{sup −}. Based on the computational results, this anion is a trapped dihydroxide intermediate in the Mo{sub 2}O{sub 5}{sup −} + H{sub 2}O/D{sub 2}O → Mo{sub 2}O{sub 6}{sup −} + H{sub 2}/D{sub 2} reaction.
Static susceptibility and heat capacity studies on V{sub 3}O{sub 7}.H{sub 2}O{sub 7} nanobelts

Energy Technology Data Exchange (ETDEWEB)

Hellmann, I., E-mail: i.hellmann@ifw-dresden.d [Leibniz-Institut fuer Festkoerper- und Werkstoffforschung (IFW) Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); Zakharova, G.S.; Volkov, V.L. [Institute of Solid State Chemistry, Ural Division, Russian Academy of Sciences, Pervomaiskaya ul. 91, Yekaterinburg 620219 (Russian Federation); Taeschner, C.; Leonhardt, A.; Buechner, B.; Klingeler, R. [Leibniz-Institut fuer Festkoerper- und Werkstoffforschung (IFW) Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany)

2010-04-15

V{sub 3}O{sub 7}.H{sub 2}O nanobelts were prepared by a hydrothermal method at 190 deg. C using V{sub 2}O{sub 5}.nH{sub 2}O gel and H{sub 2}C{sub 2}O{sub 4}.2H{sub 2}O as starting agents. The obtained nanobelts have diameters ranging from 40 to 70 nm with lengths up to several micrometers. Measurements of the static magnetic susceptibility and the specific heat show a discontinuous phase transition at around T=145 K, which separates two regions of paramagnetic behavior.
Electrical and structural characteristics of spray deposited (Zn O){sub x}-(Cd O){sub 1-x}

Energy Technology Data Exchange (ETDEWEB)

Alarcon F, G.; Pelaez R, A.; Villa G, M.; Carmona T, S.; Luna G, J. A.; Aguilar F, M. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Legaria 694, Col. Irrigacion, 11500 Mexico D. F. (Mexico); Vasquez P, B. [Universidad Autonoma Metropolitana, Unidad Azcapotzalco, Av. San Pablo No. 180, Col. Reynosa Tamaulipas, 02200 Mexico D. F. (Mexico); Falcony, C. [IPN, Centro de Investigacion y de Estudios Avanzados, Apdo. Postal 14-740, 07000 Mexico D. F. (Mexico)

2013-10-01

(Zn O){sub x}(Cd O){sub 1-x} thin films were deposited on glass substrates at 300 and 400 C by ultrasonic spray pyrolysis with compositions ranging from Cd O to Zn O. The electrical properties were obtained by impedance spectroscopy and Hall Effect measurements. Scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction, were used to study the structural characteristics of the films. Ellipsometry, in addition, was used to confirm the structural characteristics. The films as deposited resulted mainly polycrystalline and dense, depending on the substrate temperature and on their relative composition. All the films showed n-type conductivity and the films with intermediate compositions resulted in a mixture of both phases; Cd O and Zn O. Hall Effect measurements showed that the highest conductivity of Cd O was close to 1 x 10{sup 3} ({Omega}-cm){sup -1}, the highest value obtained for Cd O, without doping. Impedance spectroscopy confirmed the Hall Effect results, showing that the highly conducting character of Cd O influenced dramatically the conductivity of the (Zn O){sub x}(Cd O){sub 1-x} films. In addition, depending on the substrate temperature and on the relative composition of the films, both, the bulk or grains, as well as the grain boundaries properties limit the conductivity in them. (Author)
Use of Isotopic Techniques for the Assessment of Hydrological Processes in Wetlands (Cienaga Colombia)

Energy Technology Data Exchange (ETDEWEB)

Betancur, T.; Santa, D.; Palacio, P.; Palacio, C.; Wills, B.; Hoyos, D. A. [Universidad de Antioquia, Medellin (Colombia)

2013-07-15

The Cienaga Colombia wetland is located in the Bajo Cauca Antioqueno region where the 'Man' river flows into the Cauca River. Hydrological processes on the Cienaga Colombia wetland are complex because of the interactive effects of both local and regional elements, associated with a typical tropical wet climatic regime. In this groundwater dependent wetland hydrological studies have been conducted, including hydrochemical analyses and isotope tracers, to describe and understand the interactions between groundwater and surface water, not only for the wetland itself but also for the entire catchment area. Rain samples (five year record) were used to obtain the LML: {delta}{sup 2}H = 8.03 {delta}{sup 18}O +9.9. The evaporation line is: {delta}{sup 2}H = 5.9 {delta}{sup 18}O - 7.3. According to the analyses, both groundwater and surface waters have the same isotopic signatures. Unsustainable land use practices along with current and predicted global environmental changes may cause negative impacts on the hydrological functioning of the region, affecting primarily, but not exclusively, evapotranspiration-recharge processes and the sustainability of the entire system. (author)
Microstructure of a commercial W–1% La{sub 2}O{sub 3} alloy

Energy Technology Data Exchange (ETDEWEB)

Shen, Yinzhong, E-mail: shenyz@sjtu.edu.cn; Xu, Zhiqiang; Cui, Kai; Yu, Jie

2014-12-15

W–1% La{sub 2}O{sub 3} alloy is considered as the most promising material for plasma-facing components of fusion reactors. The microstructure of a commercial W–1% La{sub 2}O{sub 3} alloy was investigated using optical and transmission electron microscopes. The microstructure of pure tungsten can be improved significantly by fabrication of W–1% La{sub 2}O{sub 3} alloys. W–1% La{sub 2}O{sub 3} alloys can be produced with no porosities and cracks, and with various oxide phases dispersed in alloy matrix. La{sub 2}O{sub 3} with different crystal structures, La{sub 6}W{sub 2}O{sub 15}, WO{sub 2}, WO{sub 3} and W{sub 3}O{sub 8} phases were identified in as-forged W–1% La{sub 2}O{sub 3} alloy. Long strip-like La{sub 2}O{sub 3} has a very large size, whereas spherical La{sub 6}W{sub 2}O{sub 15}, navicular WO{sub 3}, hexagonal W{sub 3}O{sub 8} and short rod-like La{sub 2}O{sub 3} are smaller particles. Most identified phases have a heterogeneous distribution. Forging leads to a more dispersive distribution of large-sized La{sub 2}O{sub 3} particles but not of fine WO{sub 3} particles compared with rolling. The mechanical properties of the alloys are also discussed.
Effect of Fe{sub 2}O{sub 3} in Fe{sub 2}O{sub 3}/AP composite particles on thermal decomposition of AP and on burning rate of the composite propellant

Energy Technology Data Exchange (ETDEWEB)

Ma, Zhenye [National Special Superfine Powder Engineering Research Center, Nanjing University of Science and Technology, Nanjing, 210094 (China); Nanjing University of Technology, Nanjing (China); Li, Fengsheng; Bai, Huaping [National Special Superfine Powder Engineering Research Center, Nanjing University of Science and Technology, Nanjing, 210094 (China)

2006-12-15

A technique of composite processing of Fe{sub 2}O{sub 3} and ammonium perchlorate (AP) was employed in making the propellant. The effects of composite processing of Fe{sub 2}O{sub 3} on catalytic activity, on the thermal decomposition of AP, and on the burning rate of the composite propellant were investigated in this paper. Fe{sub 2}O{sub 3}/AP composite particles were prepared by a novel solvent-nonsolvent method. The results show that AP is successfully coated on the surface of Fe{sub 2}O{sub 3}. Composite processing of Fe{sub 2}O{sub 3} and AP can improve the catalytic activity of Fe{sub 2}O{sub 3}. Fe{sub 2}O{sub 3} exhibits better catalytic effect with increasing Fe{sub 2}O{sub 3} content. The larger interface between Fe{sub 2}O{sub 3} and AP and lower density of composite propellant (with the added Fe{sub 2}O{sub 3}/AP composite particles) are responsible for the enhancement of the catalytic activity of Fe{sub 2}O{sub 3}. (Abstract Copyright [2006], Wiley Periodicals, Inc.)
Optical properties of a new Bi{sub 38}Mo{sub 7}O{sub 78} semiconductor with fluorite-type δ-Bi{sub 2}O{sub 3} structure

Energy Technology Data Exchange (ETDEWEB)

Wang, Zuoshan; Bi, Shala; Wan, Yingpeng [State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Huang, Pengjie [College of Textile and Clothing Engineering, Soochow University, Suzhou 215006 (China); Zheng, Min, E-mail: zhengmin@suda.edu.cn [College of Textile and Clothing Engineering, Soochow University, Suzhou 215006 (China)

2017-03-31

Highlights: • Bi{sub 38}Mo{sub 7}O{sub 78} semiconductor nanoparticles were synthesized by sol-gel method. • Bi{sub 38}Mo{sub 7}O{sub 78} keeps the structural characteristics of the patrimonial δ-Bi{sub 2}O{sub 3} structure. • Bi{sub 38}Mo{sub 7}O{sub 78} show an efficient optical absorption in visible light. • Photocatalytic property was markedly enhanced for Bi{sub 38}Mo{sub 7}O{sub 78} nanoparticles. • The mechanism of this photocatalysis system was proposed. - Abstract: Bi{sup 3+}-containing inorganic materials usually show rich optical and electronic properties due to the hybridization between 6s and 6p electronic components together with the lone pair in Bi{sup 3+} ions. In this work, a new semiconductor of bismuth molybdate Bi{sub 38}Mo{sub 7}O{sub 78} (19Bi{sub 2}O{sub 3}·7MoO{sub 3}) was synthesized by the sol-gel film coating and the following heat process. The samples developed into nanoparticles with average size of 40 nm. The phase formation was verified via the XRD Rietveld structural refinement. Orthorhombic Bi{sub 38}Mo{sub 7}O{sub 78} can be regarded to be derived from the cubic δ-phase Bi{sub 2}O{sub 3} structure. The microstructure was investigated by SEM, EDX, TEM, BET and XPS measurements. The UV-vis absorption spectra showed that the band gap of Bi{sub 38}Mo{sub 7}O{sub 78} (2.38 eV) was greatly narrowed in comparison with Bi{sub 2}O{sub 3} (2.6 eV). This enhances the efficient absorption of visible light. Meanwhile, the conduction band of is wider and shows more dispersion, which greatly benefits the mobility of the light-induced charges taking part in the photocatalytic reactions. Bi{sub 38}Mo{sub 7}O{sub 78} nanoparticles possess efficient activities on the photodegradation of methylene blue (MB) solutions under the excitation of visible-light. The photocatalysis activities and mechanisms were discussed on the crystal structure characteristics and the measurements such as photoluminescence, exciton lifetime and XPS results.
A new route for the synthesis of graphene oxide–Fe{sub 3}O{sub 4} (GO–Fe{sub 3}O{sub 4}) nanocomposites and their Schottky diode applications

Energy Technology Data Exchange (ETDEWEB)

Metin, Önder [Department of Chemistry, Faculty of Science, Atatürk University, 25240 Erzurum (Turkey); Aydoğan, Şakir [Department of Physics, Faculty of Science, Atatürk University, 25240 Erzurum (Turkey); Meral, Kadem, E-mail: kademm@atauni.edu.tr [Department of Chemistry, Faculty of Science, Atatürk University, 25240 Erzurum (Turkey)

2014-02-05

Highlights: • Graphene Oxide (GO)–Fe{sub 3}O{sub 4} nanocomposites were prepared by a novel and facile method. • The successful assembly of Fe{sub 3}O{sub 4} NPs onto GO sheets was displayed by TEM. • The GO–Fe{sub 3}O{sub 4} nanocomposites/p-Si junction showed good rectifying property. -- Abstract: Addressed herein is a facile method for the preparation of magnetic graphene oxide–Fe{sub 3}O{sub 4} (GO–Fe{sub 3}O{sub 4}) nanocomposites and the rectifying properties of (GO–Fe{sub 3}O{sub 4})/p-Si junction in a Schottky diode. GO–Fe{sub 3}O{sub 4} nanocomposites were prepared by a novel method in which as-prepared GO sheets were decorated with the monodisperse Fe{sub 3}O{sub 4} nanoparticles (NPs) in dimethylformamide/chloroform mixture via a sonication process. The successful assembly of Fe{sub 3}O{sub 4} NPs onto GO sheets was displayed by transmission electron microscopy (TEM). Inductively couple plasma optical emission spectroscopy (ICP-OES) analysis of the GO–Fe{sub 3}O{sub 4} nanocomposite showed that the nanocomposite consists of 20.1 wt% Fe{sub 3}O{sub 4} NPs which provides a specific saturation magnetization (Ms) as 16 emu/g. The current–voltage (I–V) characteristics of the (GO–Fe{sub 3}O{sub 4})/p-Si junction in a Schottky diode were studied in the temperature range of 50–350 K in the steps of 25 K. It was determined that the barrier height and ideality factor of the Au/GO–Fe{sub 3}O{sub 4}/p-Si/Al Schottky diode were depended on temperature as the barrier height increased while the ideality factor decreased with increasing temperature. The experimental values of barrier height and ideality factor were varied from 0.12 eV and 11.24 at 50 K to 0.76 eV and 2.49 at 350 K, respectively. The Richardson plot exhibited non-linearity at low temperatures that was attributed to the barrier inhomogeneities prevailing at the GO–Fe{sub 3}O{sub 4}/p-Si junction.
Development and application of the mollusc Arctica islandica as a paleoceanographic tool for the North Atlantic Ocean

Energy Technology Data Exchange (ETDEWEB)

Weidman, C.R.

1995-09-01

Until now there has been no tool comparable to corals for reconstructing long term high-resolution geochemical time-series for the colder, higher-latitude oceans. In this thesis, the long-lived (+100 years) boreal mollusc (Bivalvia) Arctica islandica is shown to be practical for this purpose in the northern North Atlantic Ocean. The evidence, compiled here, demonstrates that the carbonate shell of this species faithfully records the ambient dissolved inorganic carbon`s (DIC) radiocarbon ({Delta}{sup 14}C) concentration and accurately reflects the ambient temperature in its stable oxygen isotope ({delta}{sup 18}O) composition. However, the stable carbon isotope ({delta}{sup 13}C) composition of the A. islandica shell likely is not a good recorder of ambient DIC {delta}{sup 13}C, and likely responds to physiological controls. Four {Delta}{sup 14}C time histories are reconstructed from the annual bands of A. islandica shells for the higher-latitudes of the northern North Atlantic Ocean (from 41{degree}N to 70{degree}N).
Effect of B{sub 2}O{sub 3}/P{sub 2}O{sub 5} substitution on the properties and structure of tin boro-phosphate glasses

Energy Technology Data Exchange (ETDEWEB)

Saitoh, Akira, E-mail: asaito@ehime-u.ac.jp [Graduate School of Science and Engineering, Ehime University, Matsuyama, 3 Bunkyo-cho (Japan); Tricot, Grégory [LASIR UMR-CNRS 8516, Université de Lille 1, Villeneuve d' Ascq 59655 (France); UCCS UMR-CNRS 8181, Université de Lille 1, Villeneuve d' Ascq 59655 (France); Rajbhandari, Prashant [UCCS UMR-CNRS 8181, Université de Lille 1, Villeneuve d' Ascq 59655 (France); Anan, Shoji; Takebe, Hiromichi [Graduate School of Science and Engineering, Ehime University, Matsuyama, 3 Bunkyo-cho (Japan)

2015-01-15

Effect of B{sub 2}O{sub 3}/P{sub 2}O{sub 5} substitution on the properties and structure of the ternary 67SnO–(33–x)P{sub 2}O{sub 5}–xB{sub 2}O{sub 3} composition line (from x = 0–33 mol%) are examined in this contribution. We show that density and glass transition temperature increase while molar volume and thermal expansion coefficient decrease with increasing B{sub 2}O{sub 3} concentration. Density and thermal properties experience an original three-domain evolution with rapid (region I: 0 ≤ x < 5), substantial (II: 5 < x ≤ 15), and moderate (III: 15 < x ≤ 33) increase. In order to explain this unconventional behaviour, the glass structure has been investigated using high magnetic field 1 dimensional {sup 31}P and {sup 11}B MAS–NMR, micro-Raman and infrared spectroscopies. {sup 11}B MAS–NMR experiments allow to (i) monitor the 3- and 4-fold coordinated borate species proportion and (ii) highlight the presence of unreported 4-fold coordinated species in the region (III). Finally, it is shown that substitution of P{sub 2}O{sub 5} by B{sub 2}O{sub 3} induces an alteration of the dimeric phosphate network and formation of mixed anion structure that consists of Q{sup 0} phosphate units, 3- and 4-fold coordinated borate units and their combinations. - Highlights: • We examined B{sub 2}O{sub 3}/P{sub 2}O{sub 5} substitution effect on the ternary SnO–P{sub 2}O{sub 5}–B{sub 2}O{sub 3} glasses. • We show a three-domains evolution for density and thermal properties. • The structure was investigated by {sup 31}P and {sup 11}B NMR, Raman and IR spectroscopies. • 3 and 4-folded borate species and unreported 4-folded species are revealed. • Mixed anion structure consists of Q{sup 0} phosphate unit and 3- and 4-folded borate units.
Luminescence properties of Eu{sup 2+} doped SrB{sub 4}O{sub 7} phosphor for radiation dosimetry

Energy Technology Data Exchange (ETDEWEB)

Palan, C.B., E-mail: chetanpalan27@yahoo.in; Bajaj, N.S.; Omanwar, S.K.

2016-04-15

Highlights: • Report TL/OSL properties of SrB{sub 4}O{sub 7}:Eu{sup 2+} under beta irradiations. • OSL Sensitivity was about 33% than that of commercially available α-Al{sub 2}O{sub 3.} • TL glow peaks was appear at 305° C and TL sensitivity about 200 times higher than TLD-500. • OSL decay pattern was faster than α- Al{sub 2}O{sub 3}:C and dose response was linear nature. - Abstract: In this report, we presented the TL/OSL properties of Eu doped SrB{sub 4}O{sub 7} phosphor under β-irradiation. This phosphor was synthesized by using solid state method. The phosphor shows OSL sensitivity about 33% than that of commercially available α-Al{sub 2}O{sub 3}: C phosphor. CW-OSL curve possess two components having photoionization cross-sections 0.707 × 10{sup −17} and 18.58 × 10{sup −17} cm{sup 2} respectively and TL sensitivity about 200 times higher than TLD-500. The kinetic parameters such as activation energy, frequency factor and order of kinetics of TL curve were calculated by using peak shape method. In TL/OSL mode dose-response was almost linear in the range of measurements. The MDD was found to be 1.26 mGy with 3σ of background. Also reusability studies showed the phosphor can be reused for 10 cycles with 1% change in the OSL output. The PL spectra of SrB{sub 4}O{sub 7} showed emission in NUV region when excited with 318 nm under UV source.

Exchange spring magnetic behavior in BaFe{sub 12}O{sub 19}/Fe{sub 3}O{sub 4} nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Remya, K.P. [Department of Nanoscience and Technology, Bharathiar University, Coimbatore 641 046 (India); Prabhu, D. [Centre for Automotive Energy Materials, ARCI, Chennai 600 113 (India); Amirthapandian, S. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Viswanathan, C.; Ponpandian, N. [Department of Nanoscience and Technology, Bharathiar University, Coimbatore 641 046 (India)

2016-05-15

We report the investigation on exchange spring coupling behavior of BaFe{sub 12}O{sub 19}/Fe{sub 3}O{sub 4} nanocomposite synthesized by simple mixing followed by heat treatment of individual ferrites. Morphologically tuned, well crystalline hard and soft ferrites were synthesized by simple chemical method and the phase composition, crystallinity, surface morphology and magnetic properties of the as prepared ferrites as well as the nanocomposites were studied by using XRD, FESEM and VSM respectively. Exchange coupling behavior is observed in the nanocomposite samples heated at 600 °C with simultaneous enhancements of (BH){sub max} and remanence. - Highlights: • Hard/Soft magnetic nanocomposite was prepared by simple mixing and heat treatment. • Simple chemical method was employed for the synthesis of pristine hard and soft magnetic nanostructures. • Microscopic studies show the presence of both phases. • Exchange-spring behavior was observed in BaFe{sub 12}O{sub 19}/Fe{sub 3}O{sub 4} nanocomposite. • Evaluated using switching field distribution curve.
In situ DRIFTS study of O{sub 3} adsorption on CaO, γ-Al{sub 2}O{sub 3}, CuO, α-Fe{sub 2}O{sub 3} and ZnO at room temperature for the catalytic ozonation of cinnamaldehyde

Energy Technology Data Exchange (ETDEWEB)

Wu, Jianfeng; Su, Tongming; Jiang, Yuexiu; Xie, Xinling [School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004 (China); Qin, Zuzeng, E-mail: qinzuzeng@gmail.com [School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004 (China); Ji, Hongbing, E-mail: jihb@mail.sysu.edu.cn [School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004 (China); School of Chemistry, Sun Yat-sen University, Guangzhou 510275 (China)

2017-08-01

Highlights: • In situ DRIFTS study of O{sub 3} adsorption on metal oxides at room temperature. • Using acidic probe molecules (DRIFTS) characterization of surface basicity. • Correlation between basic strength of metal oxides and O{sub 3} adsorption. • Study on the competitive adsorption of O{sub 3} and CO{sub 2}. • DRIFTS study of cinnamaldehyde ozonation and benzaldehyde excessive oxidation. - Abstract: In situ DRIFTS were conducted to identify adsorbed ozone and/or adsorbed oxygen species on CaO, ZnO, γ-Al{sub 2}O{sub 3}, CuO and α-Fe{sub 2}O{sub 3} surfaces at room temperature. Samples were characterized by means of TG, XRD, N{sub 2} adsorption–desorption, pyridine-IR, nitrobenzene-IR, chloroform-IR, and CO{sub 2}-TPD. Pyridine-DRIFTS measurements evidence two kinds of acid sites in all the samples. Nitrobenzene, chloroform-DRIFTS, and CO{sub 2}-TPD reveal that there are large amounts of medium-strength base sites on all the metal oxides, and only CaO, ZnO, and γ-Al{sub 2}O{sub 3} have strong base sites. And the benzaldehyde selectivity was increased in the same order of the alkalinity of the metal oxides. With weaker sites, ozone molecules form coordinative complexes bound via the terminal oxygen atom, observed by vibrational frequencies at 2095–2122 and 1026–1054 cm{sup −1}. The formation of ozonide O{sub 3}{sup −} at 790 cm{sup −1}, atomic oxygen at 1317 cm{sup −1}, and superoxide O{sub 2}{sup −} at 1124 cm{sup −1} was detected; these species are believed to be intermediates of O{sub 3} decomposition on strong acid/base sites. The adsorption of ozone on metal oxides is a weak adsorption, and other gases, such as CO{sub 2}, will compete with O{sub 3} adsorption. The mechanism of cinnamaldehyde ozonation at room temperature over CaO shows that cinnamaldehyde can not only be oxidized into cinnamic acid, but also be further oxidized into benzaldehyde, benzoic acid, maleic anhydride, and ultimately mineralized to CO{sub 2} in the
Resistance switching characteristics of core–shell γ-Fe{sub 2}O{sub 3}/Ni{sub 2}O{sub 3} nanoparticles in HfSiO matrix

Energy Technology Data Exchange (ETDEWEB)

Zhou, Guangdong [Guizhou Institute of Technology, Guiyang 550003 (China); Wu, Bo, E-mail: fqwubo@zync.edu.cn [Institute of Theoretical Physics, Zunyi Normal College, Zunyi 563002 (China); School of Marine Science and Technology, Northwestern Polytechnical University, Xian 710072 (China); Liu, Xiaoqin; Li, Zhiling; Zhang, Shuangju [Guizhou Institute of Technology, Guiyang 550003 (China); Zhou, Ankun [Kunming Institute of Botany, Chineses Academy Sciences, Kunming 650201 (China); Yang, Xiude [Institute of Theoretical Physics, Zunyi Normal College, Zunyi 563002 (China)

2016-09-05

Core–shell γ-Fe{sub 2}O{sub 3}/Ni{sub 2}O{sub 3} nanoparticles are synthesized by chemical co-precipitation method. Resistive switching memory behaviors, which have resistance ON/OFF ratio of ∼10{sup 2} and excellent retention property, are observed in the Au/HfSiO/γ-Fe{sub 2}O{sub 3}/Ni{sub 2}O{sub 3}/HfSiO/Pt structure. Space charge limited current (SCLC) mechanism, which is supported by the fitting current–voltage results, is employed to know the resistive switching memory effects. The transportation of Oxygen vacancy Vo{sup 2+}, oxygen ion O{sup 2−}, recombination of oxygen atom and drive of external electric field are responsible for the ON or OFF states observed in device. - Highlights: • Bipolar resistance switching effects are detected in core–shell of γ-Fe{sub 2}O{sub 3}@Ni{sub 2}O{sub 3}. • The Ohimc conduction and space-charge-limited current play an important role in Low/High field. • Rapture of filament assisted by Vo{sup 2+}, O{sup 2−} and O{sub 2} recombination is responsible for switching. • Resistance switching memory highlights excellent retention properties after stress 100 cycles.
Restricted N-glycan conformational space in the PDB and its implication in glycan structure modeling.

Science.gov (United States)

Jo, Sunhwan; Lee, Hui Sun; Skolnick, Jeffrey; Im, Wonpil

2013-01-01

Understanding glycan structure and dynamics is central to understanding protein-carbohydrate recognition and its role in protein-protein interactions. Given the difficulties in obtaining the glycan's crystal structure in glycoconjugates due to its flexibility and heterogeneity, computational modeling could play an important role in providing glycosylated protein structure models. To address if glycan structures available in the PDB can be used as templates or fragments for glycan modeling, we present a survey of the N-glycan structures of 35 different sequences in the PDB. Our statistical analysis shows that the N-glycan structures found on homologous glycoproteins are significantly conserved compared to the random background, suggesting that N-glycan chains can be confidently modeled with template glycan structures whose parent glycoproteins share sequence similarity. On the other hand, N-glycan structures found on non-homologous glycoproteins do not show significant global structural similarity. Nonetheless, the internal substructures of these N-glycans, particularly, the substructures that are closer to the protein, show significantly similar structures, suggesting that such substructures can be used as fragments in glycan modeling. Increased interactions with protein might be responsible for the restricted conformational space of N-glycan chains. Our results suggest that structure prediction/modeling of N-glycans of glycoconjugates using structure database could be effective and different modeling approaches would be needed depending on the availability of template structures.
Restricted N-glycan conformational space in the PDB and its implication in glycan structure modeling.

Directory of Open Access Journals (Sweden)

Sunhwan Jo

Full Text Available Understanding glycan structure and dynamics is central to understanding protein-carbohydrate recognition and its role in protein-protein interactions. Given the difficulties in obtaining the glycan's crystal structure in glycoconjugates due to its flexibility and heterogeneity, computational modeling could play an important role in providing glycosylated protein structure models. To address if glycan structures available in the PDB can be used as templates or fragments for glycan modeling, we present a survey of the N-glycan structures of 35 different sequences in the PDB. Our statistical analysis shows that the N-glycan structures found on homologous glycoproteins are significantly conserved compared to the random background, suggesting that N-glycan chains can be confidently modeled with template glycan structures whose parent glycoproteins share sequence similarity. On the other hand, N-glycan structures found on non-homologous glycoproteins do not show significant global structural similarity. Nonetheless, the internal substructures of these N-glycans, particularly, the substructures that are closer to the protein, show significantly similar structures, suggesting that such substructures can be used as fragments in glycan modeling. Increased interactions with protein might be responsible for the restricted conformational space of N-glycan chains. Our results suggest that structure prediction/modeling of N-glycans of glycoconjugates using structure database could be effective and different modeling approaches would be needed depending on the availability of template structures.
O{sub 2} depletion in granitic media. The Rex project

Energy Technology Data Exchange (ETDEWEB)

Puigdomenech, I. [Royal Inst. of Technology, Stockholm (Sweden); Ambrosi, J.P.; Eisenlohr, L.; Lartigue, J.E. [CNRS, Aix-en-Provence (France); Banwart, S.A. [Univ. of Sheffield (United Kingdom); Bateman, K.; Milodowski, A.E.; West, J.M. [British Geological Survey, Nottingham (United Kingdom); Griffault, L. [ANDRA (France); Gustafsson, E. [Geosigma AB, Uppsala (Sweden); Hama, K.; Yoshida, H. [JNC, Gifu (Japan). Tono Geoscience Centre; Kotelnikova, S.; Pedersen, K. [Goeteborg Univ. (Sweden); Michaud, V.; Trotignon, L. [CEA, Cadarache (France); Rivas Perez, J. [Univ. of Bradford (United Kingdom); Tullborg, E.L. [Terralogica AB, Graabo (Sweden)

2001-02-01

The redox conditions are of consequence for the performance of nuclear repositories. The presence of molecular oxygen (O{sub 2}) would affect the corrosion of canisters and the migration of radionuclides eventually released from a damaged canister. The rate of disappearance of O{sub 2} left in voids at repository closure is therefore an important information when evaluating repository designs. The REX project (Redox Experiment in Detailed Scale) has been carried out within the frame of SKB Aespoe Hard Rock Laboratory in Sweden. The aim was to determine how O{sub 2} trapped in the closed repository would react with the rock minerals in the tunnel and deposition holes and in the water conducting fractures. The REX project consisted of the following sections: Field investigations at Aespoe: Microbial O{sub 2} consumption at several sites in the Aespoe tunnel. The in situ experiment: Injection of oxygen and monitoring of O{sub 2} uptake in a confined fracture surface. The Replica Experiment: a laboratory study using the other half of the fracture surface used for the in situ experiment. Laboratory experiments: needed to support the interpretation of the field and replica experiments. Conducted with groundwaters, bacteria, and mineral samples from Aespoe. The results from the in-situ experiment were confirmed by those of the replica experiment performed in the CEA laboratory in France. Both were concordant in showing time scales for O{sub 2} uptake in the order of days. The agreement was remarkable when taking into account the differences in experimental conditions. For example, different microbial processes took place in the two experiments. Laboratory studies with rock samples demonstrated that microbial activity induced increased chemical weathering, with the formation of clay minerals. Rates of O{sub 2} uptake by fracture filling minerals were determined under laboratory conditions. These rates were faster than those reported in literature studies of pure mineral
Vivaldi: Visualization and validation of biomacromolecular NMR structures from the PDB

Science.gov (United States)

Hendrickx, Pieter M S; Gutmanas, Aleksandras; Kleywegt, Gerard J

2013-01-01

We describe Vivaldi (VIsualization and VALidation DIsplay; http://pdbe.org/vivaldi), a web-based service for the analysis, visualization, and validation of NMR structures in the Protein Data Bank (PDB). Vivaldi provides access to model coordinates and several types of experimental NMR data using interactive visualization tools, augmented with structural annotations and model-validation information. The service presents information about the modeled NMR ensemble, validation of experimental chemical shifts, residual dipolar couplings, distance and dihedral angle constraints, as well as validation scores based on empirical knowledge and databases. Vivaldi was designed for both expert NMR spectroscopists and casual non-expert users who wish to obtain a better grasp of the information content and quality of NMR structures in the public archive. © Proteins 2013. © 2012 Wiley Periodicals, Inc. PMID:23180575
Development and characterization of nickel catalysts supported in CeO{sub 2}-ZrO{sub 2}-Al{sub 2}O{sub 3}, CeO{sub 2}-La{sub 2}O{sub 3}-Al{sub 2}O{sub 3} e ZrO{sub 2}-La{sub 2}O{sub 3}-Al{sub 2}O{sub 3} matrixes evaluated for methane reforming reactions; Desenvolvimento e caracterização de catalisadores de níquel suportados em matrizes CeO{sub 2}-ZrO{sub 2}-Al{sub 2}O{sub 3}, CeO{sub 2}-La{sub 2}O{sub 3}-Al{sub 2}O{sub 3} e ZrO{sub 2}-La{sub 2}O{sub 3}-Al{sub 2}O{sub 3} avaliados para as reações de reforma do metano

Energy Technology Data Exchange (ETDEWEB)

Abreu, Amanda Jordão de

2012-07-01

Nowadays, the methane reforming is large interest industrial for the take advantage of these gas in production the hydrogen and synthesis gas (syngas). Among in the reactions of methane stand of the reactions steam reforming and carbon dioxide reforming of methane. The main catalysts uses in the methane reforming is Ni/Al{sub 2}O{sub 3}. However, the supported-nickel catalyst is susceptible to the deactivation or the destruction by coke deposition. The carbon dissolves in the nickel crystallite and its diffuses through the nickel, leading for formation of the carbon whiskers, which results in fragmentation of the catalyst. Modification of such catalysts, like incorporation of suitable promoters, is desirable to achieve reduction of the methane hydrogenolysis and/or promotion of the carbon gasification. Catalysts 5%Ni/Al{sub 2}O{sub 3} supported on solid solutions formed by ZrO{sub 2}-CeO{sub 2}, La{sub 2}O{sub 3} and CeO{sub 2}-ZrO{sub 2}-La{sub 2}O{sub 3} were prepared, characterized and evaluated in reactions steam and carbon dioxide reforming and partial oxidation of methane with objective the value effect loading solution solid in support. The supports were prepared by co-precipitation method and catalysts were prepared by impregnation method and calcined at 500 deg C. The supports and catalysts were characterized by Nitrogen Adsorption, method -rays diffraction (XRD), X-rays dispersive spectroscopy (XDS), spectroscopy in the region of the ultraviolet and the visible (UV-vis NIR) to and temperature programmed reduction (TPR), Raman Spectroscopy, X-ray absorption spectroscopy and Thermogravimetric Analysis. After all the catalytic reactions check which the addition of solid solution is beneficial for Ni/Al{sub 2}O{sub 3} catalysts and the best catalysts are Ni/CeO{sub 2}-La{sub 2}O{sub 3}-Al{sub 2}O{sub 3}. (author)
Controlled synthesis and photoluminescence properties of In{sub 2}O{sub 3} rods with dodecahedron In{sub 2}O{sub 3} microcrystals on top

Energy Technology Data Exchange (ETDEWEB)

Ouacha, Hassan [King Abdullah Institute for Nanotechnology, King Saud University, Riyadh (Saudi Arabia); Hendaoui, Ali [Department of Physics, College of Science and General Studies, Alfaisal University, Riyadh (Saudi Arabia); Kleineberg, Ulf [Faculty of Physics, Ludwig Maximilian University of Munich, Garching (Germany); Albrithen, Hamad; Azzeer, Abdallah [Physics and Astronomy Department, King Saud University, Riyadh (Saudi Arabia)

2017-10-15

In{sub 2}O{sub 3} rods with dodecahedron In{sub 2}O{sub 3} microcrystals on top were synthesized in an electrical furnace via Au-catalyzed vapor transport process. A catalyst-assisted selective vapor-solid (VS) growth was proposed to explain the formation of the dodecahedron In{sub 2}O{sub 3} microcrystal, while the self-catalytic VS growth mechanism dominated the subsequent one-dimensional (1D) growth of the In{sub 2}O{sub 3} rod underneath the In{sub 2}O{sub 3} microcrystal. The structural evolution of these structures was carefully examined during the synthesis process by controlling the growth parameters. The morphologies, crystalline structures and surface chemistry were characterized by scanning electron microscopy (SEM), X-ray diffraction technique (XRD), and X-ray photoelectron spectroscopy (XPS), respectively. The photoluminescence (PL) spectrum at room temperature of the as-grown In{sub 2}O{sub 3} structures exhibited both UV and blue luminescence emission under one excitation at 260 nm, which may be related to the existence of oxygen vacancies. The synthesized multifaceted In{sub 2}O{sub 3} microcrystal has shown to contain a large number of vertices and may find many applications in developing three-dimensional (3D) resonators. This work will not only enrich the synthesis science but also will open doors for applications of such structures in optical devices. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
On the mechanisms of titanium particle reactions in O{sub 2}/N{sub 2} and O{sub 2}/Ar atmospheres

Energy Technology Data Exchange (ETDEWEB)

Andrzejak, Timothy A.; Shafirovich, Evgeny; Varma, Arvind [School of Chemical Engineering, Purdue University, West Lafayette, IN (United States)

2009-02-15

Combustion of titanium particles in air may potentially be used for the in situ synthesis of nanoscale TiO{sub 2} particles, which can photocatalytically degrade chemical and biological air pollutants. The knowledge of Ti particle reactions in O{sub 2}-containing atmospheres is required to develop this method. In the present work, large ({proportional_to}3 mm) single Ti particles were heated by a laser in O{sub 2}/N{sub 2} and O{sub 2}/Ar environments. High-speed digital video recording, thermocouple measurements and quenching at different stages of the process were used for diagnostics. Analysis of the obtained temperature-time curves and quenched particles does not show a significant influence of nitrogen on the oxidation of solid Ti. In all experiments, noticeable surface oxidation started at temperatures between {proportional_to}850 and {proportional_to}950 C, leading to a sharp temperature rise at {proportional_to}1400 C. During prolonged heating at the Ti melting point (1670 C), a liquid TiO{sub 2} bead formed and, after an induction period, ejected fragments. It was shown that this phenomenon may result from an excess of oxygen in the liquid bead. Fragment ejection in O{sub 2}/N{sub 2} atmospheres was more intense than in O{sub 2}/Ar, indicating that N{sub 2} accelerates the oxidation of liquid Ti. (Abstract Copyright [2009], Wiley Periodicals, Inc.)
Facile fabrication of Fe{sub 3}O{sub 4} and Co{sub 3}O{sub 4} microspheres and their influence on the thermal decomposition of ammonium perchlorate

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yifu, E-mail: yfzhang@dlut.edu.cn; Meng, Changgong

2016-07-25

Fe{sub 3}O{sub 4} and Co{sub 3}O{sub 4} microspheres were successfully synthesized by the hydrothermal decomposition of iron oxalate and cobalt oxalate solution. The composition and morphology of synthesized powders were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The catalytic properties of the as-obtained Fe{sub 3}O{sub 4} and Co{sub 3}O{sub 4} microspheres on the thermal decomposition of ammonium perchlorate (AP) were evaluated by thermo-gravimetric analysis and differential thermal analysis (TGA/DTA) methods. The thermal decomposition temperatures of AP in the presence of 1, 2, 4 and 8 wt% of Fe{sub 3}O{sub 4} microspheres were respectively decreased by 58, 80, 102 and 129 °C (lowered to 398, 376, 354 and 327 °C). And the thermal decomposition temperatures of AP in the presence of 1, 2, 4 and 8 wt% of Co{sub 3}O{sub 4} microspheres were respectively decreased by 55, 74, 112 and 131 °C (lowered to 401, 382, 344 and 325 °C). The analysis of the thermal gravimetric analyzer couplet with infrared spectroscopy (TG-IR) test reveal that the additives can accelerate the thermal decomposition of AP via the high-temperature decomposition. All the results suggest the as-prepared Fe{sub 3}O{sub 4} and Co{sub 3}O{sub 4} microspheres have highly catalytic properties on the thermal decomposition of AP, which can be used as the promising additives in the future. - Graphical abstract: Real-time FTIR spectra to reveal the thermal decomposition process of AP. - Highlights: • Highly uniform Fe{sub 3}O{sub 4} and Co{sub 3}O{sub 4} microspheres were successfully synthesized. • The T{sub c} of AP with 1, 2, 4 and 8 wt% of Fe{sub 3}O{sub 4} microspheres was decreased by 58, 80, 102 and 129 °C. • The T{sub c} of AP with 1, 2, 4 and 8 wt% of Co{sub 3}O{sub 4} microspheres was decreased by 55, 74, 112 and 131 °C. • The thermal decomposition process of AP was detected by TG-IR.
Structural and magnetic properties of CoFe{sub 2}O{sub 4}/NiFe{sub 2}O{sub 4} core/shell nanocomposite prepared by the hydrothermal method

Energy Technology Data Exchange (ETDEWEB)

Sattar, A.A. [Department of Physics, Faculty of Science, Ain Shams University, 11566 Abbasia, Cairo (Egypt); EL-Sayed, H.M., E-mail: h_m_elsaid@hotmail.com [Department of Physics, Faculty of Science, Ain Shams University, 11566 Abbasia, Cairo (Egypt); ALsuqia, Ibrahim [Department of Physics, Faculty of Education and Applied Science, Hajjah University, Alshahli, Hajjah (Yemen)

2015-12-01

CoFe{sub 2}O{sub 4}/NiFe{sub 2}O{sub 4} core/shell magnetic nanocomposite was synthesized by using hydrothermal method.The analysis of XRD indicated the coexistence of CoFe{sub 2}O{sub 4}, NiFe{sub 2}O{sub 4}as core/shell composite. The core/shell structure of the composite sample has been confirmed by HR-TEM images, EDX and FT-IR measurements. The size of obtained core/shell nanoparticles was 17 nm in core diameter and about 3 nm in shell thickness. The magnetization measurements showed that both the coercive field and the saturation magnetization of the resulting core/shell nanocomposite were slightly decreased compared to those of the CoFe{sub 2}O{sub 4} core but the thermal stability is of the magnetization parameter was enhanced. Furthermore, superparamagnetic phase is established at temperatures higher than the room temperature. The results were discussed in terms of the surface pinning and the magnetic interaction at the interface between the core and shell. - Highlights: • CoFe{sub 2}O{sub 4}/NiFe{sub 2}O{sub 4} core/shell could be prepared by hydrothermal method. • The structural analysis proved the formation of NiFe{sub 2}O{sub 4} shell with thickness 3 nm. • The thermal stability of M{sub s} and H{sub c} is enhanced due to the presence of NiFe{sub 2}O{sub 4} as a shell. • Super paramagnetic transition is confirmed and the effective magnetic anisotropy was calculated.
Structural influence of aluminium, gallium and indium metal oxides by means of dielectric and spectroscopic properties of CaO-Sb{sub 2}O{sub 3}-B{sub 2}O{sub 3} glass system

Energy Technology Data Exchange (ETDEWEB)

Srinivasa Reddy, M. [Department of Physics, Acharya Nagarjuna University P.G. Centre, Nuzvid 521 201, AP (India); Naga Raju, G. [Department of Physics, Acharya Nagarjuna University P.G. Centre, Nuzvid 521 201, AP (India); Nagarjuna, G. [Department of Chemistry, Acharya Nagarjuna University, Nagarjunanagar, AP (India); Veeraiah, N. [Department of Physics, Acharya Nagarjuna University P.G. Centre, Nuzvid 521 201, AP (India)]. E-mail: nvr8@rediffmail.com

2007-07-12

Dielectric constant ({epsilon}'), loss (tan {delta}), ac conductivity ({sigma}) of CaO-Sb{sub 2}O{sub 3}-B{sub 2}O{sub 3}:M{sub 2}O{sub 3} (Al{sub 2}O{sub 3}, Ga{sub 2}O{sub 3} and In{sub 2}O{sub 3}) glasses with varying concentrations of M{sub 2}O{sub 3} (0-5 mol%), were measured as a function of frequency and temperature over moderately wide ranges. The analysis of results of these studies along with IR, Raman and optical absorption spectra and also DTA studies indicated that in the concentration ranges, 0 {<=} Al{sub 2}O{sub 3} {<=} 4, 0 {<=} Ga{sub 2}O{sub 3} {<=} 2 and 1 {<=} In{sub 2}O{sub 3} {<=} 5, Al{sup 3+}, Ga{sup 3+} ions occupy tetrahedral positions whereas In{sup 3+} ions take up octahedral substitutional positions, cross-link with the other structural units in the glass network and increase the rigidity of the glass network.
Synthesis, characterization, photocatalytic activity and ethanol-sensing properties of In{sub 2}O{sub 3} and Eu{sup 3+}:In{sub 2}O{sub 3} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Anand, Kanica; Thangaraj, R., E-mail: rthangaraj@rediffmail.com [Semiconductors Laboratory, Department of Physics, GND University, Amritsar (India); Kumar, Praveen [Department of Physics, DAV University, Jalandhar (India); Kaur, Jasmeet; Singh, R. C. [Laboratory for sensors and physical education, Department of Physics, GND University, Amritsar (India)

2015-05-15

In the present endeavor, Indium oxide (In{sub 2}O{sub 3}) and Europium doped In{sub 2}O{sub 3} (In{sub 2}O{sub 3}:0.5%Eu{sup 3+} and In{sub 2}O{sub 3}:5%Eu{sup 3+}) nanoparticles were prepared by co-precipitation method. Synthesized nanoparticles were characterized using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and UV-Visible spectrophotometry (UV-vis). XRD revealed that nanoparticles were of pure bixbyite-type cubic phase and the crystallite size decreased with the Eu{sup 3+} doping. SEM micrographs showed that particles were spherical in shape. Synthesized nanoparticles were used for photo degradation of methylene blue (MB) dye under sunlight and the results clearly showed that In{sub 2}O{sub 3}:5%Eu{sup 3+} nanoparticles exhibited higher activity than pure In{sub 2}O{sub 3} nanoparticles. For gas sensing characteristics, the nanoparticles were applied as thick film onto alumina substrate and tested at different operating temperatures. The results showed that the optimum operating temperature of the gas sensors prepared from synthesized nanoparticles is 300°C. The investigations revealed that the addition of Eu{sup 3+} as a dopant enhanced the sensing response of In{sub 2}O{sub 3} nanoparticles appreciably.
O{sub 2}(X{sup 3}Σ{sub g}{sup −}) and O{sub 2}(a{sup 1}Δ{sub g}) charge exchange with simple ions

Energy Technology Data Exchange (ETDEWEB)

Ziółkowski, Marcin; Schatz, George C., E-mail: schatz@chem.northwestern.edu [Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113 (United States); Viggiano, A. A.; Midey, Anthony [Air Force Research Laboratory, Space Vehicles Directorate, 3500 Aberdeen Ave, Kirtland AFB, New Mexico 87117 (United States); Dotan, Itzhak [Air Force Research Laboratory, Space Vehicles Directorate, 3500 Aberdeen Ave, Kirtland AFB, New Mexico 87117 (United States); Open University of Israel, 108 Ravutski St., Raanana 43107 (Israel)

2014-06-07

We present theory and experiments which describe charge transfer from the X{sup 3}Σ{sub g}{sup −} and a{sup 1}Δ{sub g} states of molecular oxygen and atomic and molecular cations. Included in this work are new experimental results for O{sub 2}(a{sup 1}Δ{sub g}) and the cations O{sup +}, CO{sup +}, Ar{sup +}, and N{sub 2}{sup +}, and new theory based on complete active space self-consistent field method calculations and an extended Langevin model to calculate rate constants for ground and excited O{sub 2} reacting with the atomic ions Ar{sup +}, Kr{sup +}, Xe{sup +}, Cl{sup +}, and Br{sup +}. The T-shaped orientation of the (X − O{sub 2}){sup +} potential surface is used for the calculations, including all the low lying states up to the second singlet state of the oxygen molecule b{sup 1}Σ{sub g}{sup +}. The calculated rate constants for both O{sub 2}(X{sup 3}Σ{sub g}{sup −}) and O{sub 2}(a{sup 1}Δ{sub g}) show consistent trends with the experimental results, with a significant dependence of rate constant on charge transfer exothermicity that does not depend strongly on the nature of the cation. The comparisons with theory show that partners with exothermicities of about 1 eV have stronger interactions with O{sub 2}, leading to larger Langevin radii, and also that more of the electronic states are attractive rather than repulsive, leading to larger rate constants. Rate constants for charge transfer involving O{sub 2}(a{sup 1}Δ{sub g}) are similar to those for O{sub 2}(X{sup 3}Σ{sub g}{sup −}) for a given exothermicity ignoring the electronic excitation of the O{sub 2}(a{sup 1}Δ{sub g}) state. This means (and the electronic structure calculations support) that the ground and excited states of O{sub 2} have about the same attractive interactions with ions.
Thermal behavior of GeO{sub 2} doped PbO-B{sub 2}O{sub 3}-ZnO-Bi{sub 2}O{sub 3} glasses

Energy Technology Data Exchange (ETDEWEB)

Cheng Yin [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China); Xiao Hanning [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China)]. E-mail: hnxiao@hnu.cn; Guo Weiming [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China); Guo Wenming [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China)

2006-05-15

PbO-B{sub 2}O{sub 3}-ZnO-Bi{sub 2}O{sub 3} glass is a representative system for vacuum and electronic sealing. Effects of GeO{sub 2} on thermal properties of the glass have been investigated in this paper. Activation energy for crystallization, glass structure, the type of crystals were characterized by differential scanning calorimetry, infrared spectroscopy, X-ray diffraction and optical microscopy. Results indicate that the addition of GeO{sub 2} (0.4-2 wt.%) to PbO-B{sub 2}O{sub 3}-ZnO-Bi{sub 2}O{sub 3} glass can suppress crystallization of the glass and decrease the sealing temperature. With the increase of GeO{sub 2} content, germanate crystals were revealed, resulting in a slight increase of sealing temperature. When the content of GeO{sub 2} is 0.7 wt.%, the glass possesses the highest stability and lowest sealing temperature (400 deg. C), which is desirable for low-temperature sealing. The coefficient of thermal expansion of PbO-B{sub 2}O{sub 3}-ZnO-Bi{sub 2}O{sub 3} glass was measured by dilatometry. The result shows that the coefficient of thermal expansion of the glass increases with the content of GeO{sub 2}. The adjustability of the coefficient of thermal expansion would expand the applications of PbO-B{sub 2}O{sub 3}-ZnO-Bi{sub 2}O{sub 3} glass. A flexural strength of 28.3 MPa was obtained at the GeO{sub 2} content of 0.7 wt.%, showing good mechanical property for sealing process.
A {mu}SR study of the magnetoresistive ruthenocuprates RuSr{sub 2}Nd{sub 1.8-x}Y {sub 0.2}Ce{sub x}Cu{sub 2}O{sub 10-{delta}} (x = 0.95 and 0.80)

Energy Technology Data Exchange (ETDEWEB)

Mclaughlin, A C [Department of Chemistry, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE (United Kingdom); Attfield, J P [Centre for Science at Extreme Conditions and School of Chemistry, University of Edinburgh, King' s Buildings, Mayfield Road, Edinburgh EH9 3JZ (United Kingdom); Van Duijn, J [Instituto de Investigacion en EnergIas Renovables, Universidad de Castilla la Mancha, Albacete, E02006 (Spain); Hillier, A D, E-mail: a.c.mclaughlin@abdn.ac.uk [ISIS facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX (United Kingdom)

2011-09-14

Zero field muon spin relaxation (ZF-{mu}SR) has been used to study the magnetic properties of the underdoped giant magnetoresistive ruthenocuprates RuSr{sub 2}Nd{sub 1.8-x}Y {sub 0.2}Ce{sub x}Cu{sub 2}O{sub 10-{delta}} (x = 0.95, 0.80). The magnetoresistance (MR) is defined so that MR = (({rho}{sub H}-{rho}{sub 0})/{rho}{sub 0}) and the giant magnetoresistive ruthenocuprates RuSr{sub 2}Nd{sub 1.8-x}Y {sub 0.2}Ce{sub x}Cu{sub 2}O{sub 10-{delta}} exhibit a large reduction in electronic resistivity upon application of a magnetic field. The ZF-{mu}SR results show a gradual loss of initial asymmetry A{sub 0} at the ruthenium spin transition temperature, T{sub Ru}. At the same time the electronic relaxation rate, {lambda}, shows a gradual increase with decreasing temperature below T{sub Ru}. These results have been interpreted as evidence for Cu spin cluster formation below T{sub Ru}. These magnetically ordered clusters grow as the temperature is decreased thus causing the initial asymmetry to decrease slowly. Giant magnetoresistance is observed over a wide temperature range in the materials studied and the magnitude increases as the temperature is reduced from T{sub Ru} to 4 K which suggests a relation between Cu spin cluster size and |-MR|. (paper)
FeatureMap3D - a tool to map protein features and sequence conservation onto homologous structures in the PDB

DEFF Research Database (Denmark)

Wernersson, Rasmus; Rapacki, Krzysztof; Stærfeldt, Hans Henrik

2006-01-01

FeatureMap3D is a web-based tool that maps protein features onto 3D structures. The user provides sequences annotated with any feature of interest, such as post-translational modifications, protease cleavage sites or exonic structure and FeatureMap3D will then search the Protein Data Bank (PDB) f...
Preparation and characterization of sol-gel derived 4%La{sub 2}O{sub 3}-Al{sub 2}O{sub 3} ceramic membrane on clay-based supports

Energy Technology Data Exchange (ETDEWEB)

Ersoy, B. [Afyon Kocatepe Univ., Mining Engineering Dept., AFYON (Turkey); Gunay, V. [TUBITAK-MRC, MCTRI, Gebze-KOCAELI (Turkey)

2004-07-01

In this work, {gamma}-Al{sub 2}O{sub 3} membrane layer (4 wt% La{sub 2}O{sub 3}+96% Al{sub 2}O{sub 3}) was coated on the clay based porous support by using the sol-gel coating. The coating solution was prepared by using boehmite (AlOOH), La-nitrate (La{sub 2}(NO{sub 3}){sub 3}.6H{sub 2}O), PVA, distilled water and HNO{sub 3}. The thickness of the {gamma}-Al{sub 2}O{sub 3} membrane layer was between 5-7 {mu}m. Two unprocessed clay samples which were supplied from Kutahya and Balikesir regions, were used to produce supports for the membranes. Porosities of the supports were varied from 25 to 40% depending on sintering temperatures. Mean pore diameter of the supports were between 0.01-1{mu}m. The mean pore diameter of 4wt%La{sub 2}O{sub 3} - Al{sub 2}O{sub 3} membrane layer was around 11 nm and total pore area was 113 m{sup 2} / g at 1000 C for 1 hour. (orig.)
Two actinide-organic frameworks constructed by a tripodal flexible ligand: Occurrence of infinite ((UO{sub 2})O{sub 2}(OH){sub 3}){sub 4n} and hexanuclear (Th{sub 6}O{sub 4}(OH){sub 4}) motifs

Energy Technology Data Exchange (ETDEWEB)

Liang, Lingling; Zhang, Ronglan [College of Chemistry and Materials, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of education, Northwest University, Xi’an 710069 (China); Zhao, Jianshe, E-mail: jszhao@nwu.edu.cn [College of Chemistry and Materials, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of education, Northwest University, Xi’an 710069 (China); Liu, Chiyang, E-mail: lcy@nwu.edu.cn [Department of Geology, Northwest University, Xi’an 710069 (China); Weng, Ng Seik [The University of Nottingham Malaysia Campus, 43500 Semenyih, Selangor Darul Ehsan (Malaysia)

2016-11-15

Two new actinide metal-organic frameworks were constructed by using a tripodal flexible ligand tris (2-carboxyethyl) isocyanurate (H{sub 3}tci) under hydrothermal condition. The combination of H{sub 3}tci and uranyl nitrate hexahydrate in aqueous solution leads to the isolation of [(UO{sub 2}){sub 2}(H{sub 2}O){sub 4}]{sub 0.5}(tci){sub 2}(UO{sub 2}){sub 4}(OH){sub 4}·18H{sub 2}O (1), which contains two distinct UO{sub 2}{sup 2+} coordination environments. Four uranyl cations, linked through μ{sub 3}-OH respectively, result in the edge-sharing ribbons. Then, the layer structure is constructed by U-O clusters linked through other eight-coordinated uranyl unions, giving rise to a porous structure in the space. Topological analysis reveals that complex 1 belongs to a (4, 8)-connected net with a schläfli symbol of (3{sup 4.}2{sup 6.}3){sub 2}(3{sup 4.}4{sup 6.}5{sup 6.}6{sup 8.}7{sup 3.}8). Th{sub 3}(tci){sub 2}O{sub 2}(OH){sub 2}(H{sub 2}O){sub 3}·12H{sub 2}O (2) generated by the reaction of H{sub 3}tci and thorium nitrate tetrahydrate, possesses nine-fold coodinated Th(IV) centers with a monocapped square antiprismatic geometry. The hexamers “Th{sub 6}O{sub 4}(OH){sub 4}” motifs are connected together by the carboxylate groups, showing a three-dimensional structures. Complex 2 takes on an 8-connected architecture and the point symbol is (4{sup 24.}6{sup 4}). - Graphical abstract: Two new 3D actinide metal-organic frameworks were constructed by using a tripodal flexible ligand tris (2-carboxyethyl) isocyanurate (H3tci) and their topological structures were displayed. The infinite ((UO{sub 2})O{sub 2}(OH){sub 3}){sub 4n} and hexanuclear (Th{sub 6}O{sub 4}(OH){sub 4}) motifs were found in the title actinides networks.

Preparation of Cu/La{sub 2}O{sub 3}-ZrO{sub 2}-Al{sub 2}O{sub 3} catalyst and its catalytic properties for selective reduction of NO

Energy Technology Data Exchange (ETDEWEB)

Xi-kun Guo; Ping-ping Xie; Shu-dong Lin [Shantou University, Shantou (China). Department of Chemistry

2008-12-15

An La{sub 2}O{sub 3}-ZrO{sub 2}-Al{sub 2}O{sub 3} composite support was prepared by co-precipitation with the mixed aqueous solution of La(NO{sub 3}{sub 3}, Al(NO{sub 3){sub 3}, and ZrOCl{sub 2} dropping into the precipitant of (NH{sub 4})2CO{sub 3} aqueous solution. The Cu/La{sub 2}O{sub 3}-ZrO{sub 2}-Al{sub 2}O{sub 3} catalyst was prepared by the impregnation of La{sub 2}O{sub 3}-ZrO{sub 2}-Al{sub 2}O{sub 3} with active component Cu{sup 2+} aqueous solution. The effects of the catalyst on the selective catalytic reduction of NO with propylene in excess oxygen were investigated. The relationships between the preparation method, structure and properties of the Cu/La{sub 2}O{sub 3}-ZrO{sub 2}-Al{sub 2}O{sub 3} catalyst were also explored by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), surface area measurements (BET), pyridine absorption infrared spectrum (Py-IR), thermal gravimetry (TG), and temperature-programmed reduction (TPR). The results indicate that the support {gamma}-Al{sub 2}O{sub 3} prepared by Al(NO{sub 3})3 dropping into (NH{sub 4}{sub 2} CO{sub 3} can remarkably enlarge the surface area; the addition of La{sub 2}O{sub 3} contributes mainly to the enhancement of the thermal stability; and the introduction of ZrO{sub 2} can increase the amount of Lewis and Broenstead acid. Consequently, the catalyst Cu/La{sub 2}O{sub 3}-ZrO{sub 2}-Al{sub 2}O{sub 3} has excellent activity for the selective reduction of NO with propylene in excess oxygen. NO conversion is up to 88.9% at 300{sup o}C and 81.9% even at the presence of 10% volume fraction of water vapor. 15 refs., 8 figs., 1 tab.
Light emission efficiency and imaging performance of Lu{sub 2}O{sub 3}:Eu nanophosphor under X-ray radiography conditions: Comparison with Gd{sub 2}O{sub 2}S:Eu

Energy Technology Data Exchange (ETDEWEB)

Seferis, I. [Faculty of Chemistry, Wroclaw University, 14F Joliot-Curie Street, 50-383 Wroclaw (Poland); Department of Medical Physics, Medical School, University of Patras, 265 00 Patras (Greece); Michail, C.; Valais, I. [Department of Biomedical Engineering, Technological Educational Institute of Athens, 122 10 Athens (Greece); Zeler, J. [Faculty of Chemistry, Wroclaw University, 14F Joliot-Curie Street, 50-383 Wroclaw (Poland); Liaparinos, P.; Fountos, G.; Kalyvas, N.; David, S. [Department of Biomedical Engineering, Technological Educational Institute of Athens, 122 10 Athens (Greece); Stromatia, F. [Department of Radiology and Nuclear Medicine, “IASO” General Hospital, Mesogion 264, 15562 Holargos (Greece); Zych, E. [Faculty of Chemistry, Wroclaw University, 14F Joliot-Curie Street, 50-383 Wroclaw (Poland); Kandarakis, I., E-mail: kandarakis@teiath.gr [Department of Biomedical Engineering, Technological Educational Institute of Athens, 122 10 Athens (Greece); Panayiotakis, G. [Department of Medical Physics, Medical School, University of Patras, 265 00 Patras (Greece)

2014-07-01

Nanocrystallic europium-activated lutetium oxide (Lu{sub 2}O{sub 3}:Eu) is a strong candidate for use in digital medical imaging applications, due to its spectroscopic and structural properties. The aim of the present study was to investigate the imaging and efficiency properties of a 33.3 mg/cm{sup 2} Lu{sub 2}O{sub 3}:Eu scintillating screen coupled to a high resolution RadEye HR CMOS photodetector under radiographic imaging conditions. Since Lu{sub 2}O{sub 3}:Eu emits light in the red wavelength range, the light emission efficiency and the imaging performance were compared with results for a Gd{sub 2}O{sub 2}S:Eu phosphor screen. Parameters such as the Absolute Efficiency (AE), the X-ray Luminescence Efficiency (XLE), and the Detector Quantum Gain (DQG), were investigated. The imaging characteristics of Lu{sub 2}O{sub 3}:Eu nanophosphor screen were investigated in terms of the Modulation Transfer Function (MTF), the Normalized Noise Power Spectrum (NNPS) and the Detective Quantum Efficiency (DQE). It was found that Lu{sub 2}O{sub 3}:Eu nanophosphor has higher AE and XLE by a factor of 1.32 and 1.37 on average, respectively, in the whole radiographic energy range in comparison with the Gd{sub 2}O{sub 2}S:Eu screen. DQG was also found higher in the energy range from 50 kVp to 100 kVp and comparable thereafter. The imaging quality of Lu{sub 2}O{sub 3}:Eu nanophosphor coupled to the CMOS sensor was found to outmatch in any aspect in comparison with the Gd{sub 2}O{sub 2}S:Eu screen. These results indicate that Lu{sub 2}O{sub 3}:Eu nanophosphor could be considered for further research in order to be used in medical imaging applications. - Highlights: • AE and XLE of Lu{sub 2}O{sub 3}:Eu nanophosphor were higher by a factor of 1.32 and 1.37 than Gd{sub 2}O{sub 2}S:Eu. • DQG was higher from 50 to 100 kVp and comparable thereafter. • Imaging performance of Lu{sub 2}O{sub 3}:Eu/CMOS was better than that of Gd{sub 2}O{sub 2}S:Eu/CMOS.
Outcome of the First wwPDB Hybrid/Integrative Methods Task Force Workshop

Science.gov (United States)

Sali, Andrej; Berman, Helen M.; Schwede, Torsten; Trewhella, Jill; Kleywegt, Gerard; Burley, Stephen K.; Markley, John; Nakamura, Haruki; Adams, Paul; Bonvin, Alexandre M.J.J.; Chiu, Wah; Dal Peraro, Matteo; Di Maio, Frank; Ferrin, Thomas E.; Grünewald, Kay; Gutmanas, Aleksandras; Henderson, Richard; Hummer, Gerhard; Iwasaki, Kenji; Johnson, Graham; Lawson, Catherine L.; Meiler, Jens; Marti-Renom, Marc A.; Montelione, Gaetano T.; Nilges, Michael; Nussinov, Ruth; Patwardhan, Ardan; Rappsilber, Juri; Read, Randy J.; Saibil, Helen; Schröder, Gunnar F.; Schwieters, Charles D.; Seidel, Claus A. M.; Svergun, Dmitri; Topf, Maya; Ulrich, Eldon L.; Velankar, Sameer; Westbrook, John D.

2016-01-01

Summary Structures of biomolecular systems are increasingly computed by integrative modeling that relies on varied types of experimental data and theoretical information. We describe here the proceedings and conclusions from the first wwPDB Hybrid/Integrative Methods Task Force Workshop held at the European Bioinformatics Institute in Hinxton, UK, October 6 and 7, 2014. At the workshop, experts in various experimental fields of structural biology, experts in integrative modeling and visualization, and experts in data archiving addressed a series of questions central to the future of structural biology. How should integrative models be represented? How should the data and integrative models be validated? What data should be archived? How should the data and models be archived? What information should accompany the publication of integrative models? PMID:26095030
Spin-glass like behaviour in the nanoporous Fe{sub 2}O{sub 3} with amorphous structure

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Thakur, M; Majumdar, S; Giri, S [Department of Solid State Physics and Center for Advanced Materials, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032 (India); Bhaumik, A; Nandi, M [Department of Materials Science and Center for Advanced Materials, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032 (India); Nakamura, H; Kobayashi, H; Kohara, T [Graduate School of Material Science, University of Hyogo, Kamigori, Ako-gun, Hyogo 678-1297 (Japan)], E-mail: sspsg2@iacs.res.in

2008-07-23

The porous Fe{sub 2}O{sub 3} was synthesized chemically. The average size of the particle was {approx}85.0 nm, which was observed by scanning electron microscopy. The signature of porous structure was confirmed by a N{sub 2} adsorption/desorption isotherm and intense x-ray powder diffraction peak at low angle. The x-ray diffraction pattern at high angle indicates the amorphous structure. Moessbauer investigations show that the value of the hyperfine field is {approx}498.0 kOe at 4.2 K which is much smaller than that of the hyperfine field of crystalline {alpha}/{gamma}-Fe{sub 2}O{sub 3} and consistent with the values of amorphous Fe{sub 2}O{sub 3}. The temperature dependence of zero-field cooled magnetization exhibits a peak at 18.0 K (T{sub f}), where T{sub f} follows the Almeida-Thouless relation as T{sub f} {proportional_to} H{sup 2/3}. The ageing phenomenon of the magnetic relaxation below T{sub f} and the memory effect in the field-cooled magnetization indicate the typical features of the classical spin-glass compounds below the spin freezing temperature at T{sub f}.
Characterization of magnetic nano particles of CoFe{sub 2}O{sub 4} and CoZnFe{sub 2}O{sub 4} prepared by the chemical co-precipitation method; Caracterizacion de nanoparticulas magneticas de CoFe{sub 2}O{sub 4} y CoZnFe{sub 2}O{sub 4} preparadas por el metodo de coprecipitacion quimica

Energy Technology Data Exchange (ETDEWEB)

Lopez, J.; Zambrano, G.; Gomez, M. E. [Universidad del Valle, Departamento de Fisica, Laboratorio de Peliculas Delgadas, Ciudad Universitaria Melendez, 25360 Cali (Colombia); Prieto, P. [Universidad del Valle, Centro de Excelencia en Nuevos Materiales, Ciudad Universitaria Melendez, 25360 Cali (Colombia); Espinoza B, F. J., E-mail: javierlo21@gmail.com [IPN, Centro de Investigacion y de Estudios Avanzados, Unidad Queretaro, Libramiento Norponiente No. 2000, Fracc. Real de Juriquilla, 76230 Queretaro (Mexico)

2012-07-01

Magnetic cobalt ferrite nanoparticles of CoFe{sub 2}O{sub 4} and CoZnFe{sub 2}O{sub 4} were prepared by co-precipitation technique from aqueous salt solutions of Co (II), ZnSO{sub 4} and Fe (III), in an alkaline medium. CoFe{sub 2}O{sub 4} powder samples were structurally characterized by X-ray diffraction, showing the presence of the most intense peat at 2{theta} = 413928{sup o} (Co K{alpha}1) corresponding to the (311) crystallographic orientation of the CoFe{sub 2}O{sub 4} spinel phase. The mean size of the crystalline of CoFe{sub 2}O{sub 4} and CoZnFe{sub 2}O{sub 4} nanoparticles determined from the full width at half maximum of the strongest reflection of the (311) peak by using the Scherrer approximation was calculated to be 11.4 and 7.0 ({+-} o.2) nm, respectively. Transmission electron microscopy studies permitted determining nanoparticle size of CoZnFe{sub 2}O{sub 4}. Fourier transform infrared spectroscopy was used to confirm the formation of Fe-O bonds, allowing identifying the presence of ferrite spinel structure. Magnetic properties were investigated with the aid of a vibrating sample magnetometer at room temperature Herein, the sample showed superparamagnetic behavior, determined by the hysteresis loop finally, due to the hysteresis loop of the CoZnFe{sub 2}O{sub 4} is very small, our magnetic nanoparticles can be considered as a soft magnetic material. These magnetic nanoparticles have interesting technological applications in biomedicine given their biocompatibility, in nano technology, and in ferro fluid preparation. (Author)
Electrical and optical properties of thermally-evaporated thin films from A{sub 2}[TiO(C{sub 2}O{sub 4}){sub 2}] (A = K, PPh{sub 4}) and 1,8-dihydroxyanthraquinone

Energy Technology Data Exchange (ETDEWEB)

Carbia-Ruelas, E. [Coordinacion de Ingenieria Mecatronica. Facultad de Ingenieria, Universidad Anahuac Mexico Norte. Avenida Universidad Anahuac 46, Col. Lomas Anahuac, 52786, Huixquilucan (Mexico); Sanchez-Vergara, M.E., E-mail: elena.sanchez@anahuac.mx [Coordinacion de Ingenieria Mecatronica. Facultad de Ingenieria, Universidad Anahuac Mexico Norte. Avenida Universidad Anahuac 46, Col. Lomas Anahuac, 52786, Huixquilucan (Mexico); Garcia-Montalvo, V. [Instituto de Quimica, Universidad Nacional Autonoma de Mexico. Circuito Exterior, Ciudad Universitaria, 04510, Mexico, D. F (Mexico); Morales-Saavedra, O.G. [Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, CCADET-UNAM. A. P. 70-186, Coyoacan, 04510, Mexico, D. F (Mexico); Alvarez-Bada, J.R. [Coordinacion de Ingenieria Mecatronica. Facultad de Ingenieria, Universidad Anahuac Mexico Norte. Avenida Universidad Anahuac 46, Col. Lomas Anahuac, 52786, Huixquilucan (Mexico)

2011-02-01

In this work, the synthesis of molecular materials formed from A{sub 2}[TiO(C{sub 2}O{sub 4}){sub 2}] (A = K, PPh4) and 1,8 dihydroxyanthraquinone is reported. The synthesized materials were characterized by atomic force microscopy (AFM), infrared (IR) and ultraviolet-visible (UV-vis) spectroscopy. IR spectroscopy showed that the molecular-material thin-films, deposited by vacuum thermal evaporation, exhibit the same intra-molecular vibration modes as the starting powders, which suggests that the thermal evaporation process does not alter the initial chemical structures. Electrical transport properties were studied by dc conductivity measurements. The electrical activation energies of the complexes, which were in the range of 0.003-1.16 eV, were calculated from Arrhenius plots. Optical absorption studies in the wavelength range of 190-1090 nm at room temperature showed that the optical band gaps of the thin films were around 1.9-2.3 eV for direct transitions Eg{sub d}. The cubic NLO effects were substantially enhanced for materials synthesized from K{sub 2}[TiO(C{sub 2}O{sub 4}){sub 2}], where {chi}{sup (3)} (-3{omega}; {omega}, {omega}, {omega}) values in the promising range of 10{sup -12} esu have been evaluated.
Gas sensing behaviour of Cr{sub 2}O{sub 3} and W{sup 6+}: Cr{sub 2}O{sub 3} nanoparticles towards acetone

Energy Technology Data Exchange (ETDEWEB)

Kohli, Nipin, E-mail: nipinkohli82@yahoo.com; Hastir, Anita; Singh, Ravi Chand [Department of Physics, Guru Nanak Dev University, Amritsar-143005 (India)

2016-05-23

This paper reports the acetone gas sensing properties of Cr{sub 2}O{sub 3} and 2% W{sup 6+} doped Cr{sub 2}O{sub 3} nanoparticles. The simple cost-effective hydrolysis assisted co-precipitation method was adopted. Synthesized samples were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) techniques. XRD revealed that synthesized nanoparticles have corundum structure. The lattice parameters have been calculated by Rietveld refinement; and strain and crystallite size have been calculated by using the Williamson-Hall plots. For acetone gas sensing properties, the nanoparticles were applied as thick film onto alumina substrate and tested at different operating temperatures. The results showed that the optimum operating temperature of both the gas sensors is 250°C. At optimum operating temperature, the response of Cr{sub 2}O{sub 3} and 2% W{sup 6+} doped Cr{sub 2}O{sub 3} gas sensor towards 100 ppm acetone was found to be 25.5 and 35.6 respectively. The investigations revealed that the addition of W{sup 6+} as a dopant enhanced the sensing response of Cr{sub 2}O{sub 3} nanoparticles appreciably.
High temperature oxidation-sulfidation behavior of Cr-Al{sub 2}O{sub 3} and Nb-Al{sub 2}O{sub 3} composites densified by spark plasma sintering

Energy Technology Data Exchange (ETDEWEB)

Saucedo-Acuna, R.A. [Instituto e Ingenieria y Tecnologia, Universidad Autonoma de Cd. Juarez, Av. Del Charro 450 Norte, Col. Partido Romero, C.P. 32310, Cd. Juarez, Chihuahua (Mexico); Monreal-Romero, H.; Martinez-Villafane, A. [Centro de Investigacion en Materiales Avanzados, Departamento de Fisica de Materiales, Miguel de Cervantes 120, Complejo Industrial Chihuahua, C.P. 31109, Chihuahua (Mexico); Chacon-Nava, J.G. [Centro de Investigacion en Materiales Avanzados, Departamento de Fisica de Materiales, Miguel de Cervantes 120, Complejo Industrial Chihuahua, C.P. 31109, Chihuahua (Mexico)], E-mail: jose.chacon@cimav.edu.mx; Arce-Colunga, U. [Centro de Investigacion en Materiales Avanzados, Departamento de Fisica de Materiales, Miguel de Cervantes 120, Complejo Industrial Chihuahua, C.P. 31109, Chihuahua (Mexico); Universidad Autonoma de Tamaulipas, Matamoros 8 y 9 Col. Centro C.P. 87110, Cd. Victoria, Tamaulipas (Mexico); Gaona-Tiburcio, C. [Centro de Investigacion en Materiales Avanzados, Departamento de Fisica de Materiales, Miguel de Cervantes 120, Complejo Industrial Chihuahua, C.P. 31109, Chihuahua (Mexico); De la Torre, S.D. [Centro de Investigacion e Innovacion Tecnologica (CIITEC)-IPN, D.F. Mexico (Mexico)

2007-12-15

The high temperature oxidation-sulfidation behavior of Cr-Al{sub 2}O{sub 3} and Nb-Al{sub 2}O{sub 3} composites prepared by mechanical alloying (MA) and spark plasma sintering (SPS) has been studied. These composite powders have a particular metal-ceramic interpenetrating network and excellent mechanical properties. Oxidation-sulfidation tests were carried out at 900 deg. C, in a 2.5%SO{sub 2} + 3.6%O{sub 2} + N{sub 2}(balance) atmosphere for 48 h. The results revealed the influence of the sintering conditions on the specimens corrosion resistance, i.e. the Cr-Al{sub 2}O{sub 3} and Nb-Al{sub 2}O{sub 3} composite sintered at 1310 deg. C/4 min showed better corrosion resistance (lower weight gains) compared with those found for the 1440 deg. C/5 min conditions. For the former composite, a protective Cr{sub 2}O{sub 3} layer immediately forms upon heating, whereas for the later pest disintegration was noted. Thus, under the same sintering conditions the Nb-Al{sub 2}O{sub 3} composites showed the highest weight gains. The oxidation products were investigated by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy.
Isotopic Characterization of Snow, Ice and Glacial Melt in the Western Himalayas, India

Energy Technology Data Exchange (ETDEWEB)

Rai, S. P.; Kumar, B.; Arora, M.; Singh, R. D. [National Institute of Hydrology, Roorkee, 247 667 (India)

2013-07-15

Precipitation and glacial melt samples were collected at the snout of the Gangotri Glacier, popularly known as Gaumukh, located in the western Himalayas, India. Snow and ice samples were collected from different sites of the Gangotri Glacier. The local meteoric water line (LMWL) developed for the ablation period (May to October) is {delta}{sup 2}H = 8.2 {delta}{sup 18}O + 17.1 (r{sup 2} = 0.99), which shows a slightly higher slope and intercept than GMWL. This may be due to local summer connective precipitation occurring under dry climatic conditions and mountainous region moisture recycling with the south-west monsoon. The meltwater line, {delta}{sup 2}H =9.4 {delta}{sup 18}O + 37.5 (r{sup 2}= 0.96), having a significantly higher slope and intercept than the GMWL and LMWL. The main reasons for the higher slope and intercept of meltwater line may be due to the recycling of local vapour with moisture derived from the Western disturbance moisture whose source is the Mediterranean sea. The high d-exess values of snow, ice and meltwater indicate that the source of moisture is the Western disturbances. (author)
Optimization of α-Fe{sub 2}O{sub 3}@Fe{sub 3}O{sub 4} incorporated N-TiO{sub 2} as super effective photocatalysts under visible light irradiation

Energy Technology Data Exchange (ETDEWEB)

Mohamed, Mohamed Mokhtar, E-mail: mohmok2000@yahoo.com [Benha University, Faculty of Science, Chemistry Department, Benha (Egypt); Bayoumy, W.A. [Benha University, Faculty of Science, Chemistry Department, Benha (Egypt); Goher, M.E. [National Institute of Oceanography & Fisheries, Environmental Chemistry, Cairo (Egypt); Abdo, M.H., E-mail: mh_omr@yahoo.com [National Institute of Oceanography & Fisheries, Environmental Chemistry, Cairo (Egypt); Mansour El-Ashkar, T.Y. [National Institute of Oceanography & Fisheries, Environmental Chemistry, Cairo (Egypt)

2017-08-01

Highlights: • The α-Fe{sub 2}O{sub 3}/Fe{sub 3}O{sub 4} doped n-TiO{sub 2} was synthesized via deposition-self assembly technique. • The photocatalyst 1%α-Fe{sub 2}O{sub 3}/Fe{sub 3}O{sub 4}/n-TiO{sub 2} show a remarkable performance while MB degradation. • The strong interaction between α-Fe{sub 2}O{sub 3}/Fe{sub 3}O{sub 4} and n-TiO{sub 2} plays an important role. • It exhibits a unique textural, optical and charge transfer properties. - Abstract: Well dispersed α-Fe{sub 2}O{sub 3}@Fe{sub 3}O{sub 4} nanoparticles (7 nm) supported on mesoporous nitrogen doped titanium dioxide (N-TiO{sub 2}) are synthesized by deposition self-assembly route and their performances as photocatalysts toward methylene blue (MB) degradation are evaluated. The results illustrate that the spherical yolk-shell structure of α-Fe{sub 2}O{sub 3}@Fe{sub 3}O{sub 4}@N-TiO{sub 2} at the loading of 1%; of excellent S{sub BET} (187 m{sup 2} g{sup −1}) and pore volume (0.50 cm{sup 3} g{sup −1}), achieved high photocatalytic performance for the MB degradation (20 ppm, λ > 420 nm, lamp power = 160 W) under visible light illumination (k = 0.059 min{sup −1}). The influence of the interface formation between α-Fe{sub 2}O{sub 3}@Fe{sub 3}O{sub 4} and n-TiO{sub 2} affects severely the charges separation efficiency and enhances the electron transfer to keep on the existence of Fe{sup 3+}/Fe{sup 2+} moieties; those take significant role in the reaction mechanism. The existence of the latter junction is affirmed via XRD, TEM-SAED, Raman and FTIR techniques whereas, the photogenerated charges, their separation together with their transport and recombination rates are depicted via photoluminescence, electrical conductivity, incident photon to current efficiency (IPCE), cyclic voltammetry (CV) and impedance (EIS) measurements. The catalyst loading, zero point charge, pH variation, total organic carbon (TOC%) and the effect of lamps power are thoroughly investigated. The 1%α-Fe{sub 2}O{sub 3
New vanadium tellurites: Syntheses, structures, optical properties of noncentrosymmetric VTeO{sub 4}(OH), centrosymmetric Ba{sub 2}V{sub 4}O{sub 8}(Te{sub 3}O{sub 10})

Energy Technology Data Exchange (ETDEWEB)

Liang, Ming-Li [College of Chemistry, Fuzhou University, Fuzhou, Fujian 350108 (China); State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002 (China); Marsh, Matthew [Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306 (United States); Shang, Xian-Xing [College of Chemistry, Fuzhou University, Fuzhou, Fujian 350108 (China); State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002 (China); Mao, Jiang-Gao [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002 (China); Albrecht-Schmitt, Thomas E. [Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306 (United States); Kong, Fang, E-mail: kongfang@fjirsm.ac.cn [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002 (China); Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306 (United States)

2017-05-15

Two new vanadium tellurites, VTeO{sub 4}(OH) (1) and Ba{sub 2}V{sub 4}O{sub 8}(Te{sub 3}O{sub 10}) (2), have been synthesized successfully with the use of hydrothermal reactions. The crystal structures of the two compounds were determined by single-crystal X-ray diffraction. Compound 1 crystallizes in the polar space group Pca2{sub 1} (No. 29) while compound 2 crystallizes in the centrosymmetric space group C2/c (No. 15). The topography of compound 1 reveals a two-dimensional, layered structure comprised of VO{sub 6} octahedral chains and TeO{sub 3}(OH) zig-zag chains. Compound 2, on the contrary, features a three-dimensional [V{sub 4}O{sub 8}(Te{sub 3}O{sub 10})]{sup 4-} anionic framework with Ba{sup 2+} ions filled into the 10-member ring helical tunnels. The [V{sub 4}O{sub 8}(Te{sub 3}O{sub 10})]{sup 4-} anionic network is the first 3D vanadium tellurite framework to be discovered in the alkaline-earth vanadium tellurite system. Powder second harmonic generation (SHG) measurements indicate that compound 1 shows a weak SHG response of about 0.3×KDP (KH{sub 2}PO{sub 4}) under 1064 nm laser radiation. Infrared spectroscopy, elemental analysis, thermal analysis, and dipole moment calculations have also been carried out. - Graphical abstract: VTeO{sub 4}(OH) (1) crystallizes in the noncentrosymmetric space group Pca2{sub 1} (No. 29) while Ba{sub 2}V{sub 4}O{sub 8}(Te{sub 3}O{sub 10}) (2) crystallizes in the centrosymmetric space group C2/c (No. 15). - Highlights: • VTeO{sub 4}(OH) (1) and Ba{sub 2}V{sub 4}O{sub 8}(Te{sub 3}O{sub 10}) (2) have been synthesized successfully with the use of hydrothermal reactions. • VTeO{sub 4}(OH) (1) crystallizes in the noncentrosymmetric space group Pca2{sub 1} and displays a weak SHG response. • VTeO{sub 4}(OH) (1) represents only the fourth SHG-active material found in vanadium tellurite systems. • Ba{sub 2}V{sub 4}O{sub 8}(Te{sub 3}O{sub 10}) (2) exhibits a novel three-dimensional [V{sub 4}O{sub 8}(Te{sub 3}O{sub 10
ORF Alignment: NC_000913 [GENIUS II[Archive

Lifescience Database Archive (English)

Full Text Available ... Formate-Lyase With Pyruvate pdb|1H18|B Chain B, Pyruvate ... Formate-Lyase (E.Coli) In Complex ...With Pyruvate ... pdb|1H18|A Chain A, Pyruvate Formate-Lyase (E.Coli) In ... ... ... Complex With Pyruvate pdb|1H17|A Chain A, Pyruvate ... Formate-Lyase (E.Coli) In Complex Wi...th Coa And The ... Substrate Analog Oxamate pdb|1H16|A Chain A, Pyruvate ... Formate-Lyase (E.Coli...) In Complex With Pyruvate And Coa ... pdb|3PFL|B Chain B, Crystal Structure Of Pfl From E.Coli
Oxygen isotope geochemistry of The Geysers reservoir rocks, California

Energy Technology Data Exchange (ETDEWEB)

Gunderson, Richard P.; Moore, Joseph N.

1994-01-20

Whole-rock oxygen isotopic compositions of Late Mesozoic graywacke, the dominant host rock at The Geysers, record evidence of a large liquid-dominated hydrothermal system that extended beyond the limits of the present steam reservoir. The graywackes show vertical and lateral isotopic variations that resulted from gradients in temperature, permeability, and fluid composition during this early liquid-dominated system. All of these effects are interpreted to have resulted from the emplacement of the granitic "felsite" intrusion 1-2 million years ago. The {delta}{sup 18}O values of the graywacke are strongly zoned around a northwest-southeast trending low located near the center of and similar in shape to the present steam system. Vertical isotopic gradients show a close relationship to the felsite intrusion. The {delta}{sup 18}O values of the graywacke decrease from approximately 15 per mil near the surface to 4-7 per mil 300 to 600 m above the intrusive contact. The {delta}{sup 18}O values then increase downward to 8-10 per mil at the felsite contact, thereafter remaining nearly constant within the intrusion itself. The large downward decrease in {delta}{sup 18}O values are interpreted to be controlled by variations in temperature during the intrusive event, ranging from 150{degree}C near the surface to about 425{degree}C near the intrusive contact. The upswing in {delta}{sup 18}O values near the intrusive contact appears to have been caused by lower rock permeability and/or heavier fluid isotopic composition there. Lateral variations in the isotopic distributions suggests that the effects of temperature were further modified by variations in rock permeability and/or fluid-isotopic composition. Time-integrated water:rock ratios are thought to have been highest within the central isotopic low where the greatest isotopic depletions are observed. We suggest that this region of the field was an area of high permeability within the main upflow zone of the liquid
Preparation mechanism of (Bi{sub 2}O{sub 3}){sub 0.75}(Dy{sub 2}O{sub 3}){sub 0.25} nano-crystalline solid electrolyte

Energy Technology Data Exchange (ETDEWEB)

Li Rong [Nano-science and Nano-technology Research Center, School of Materials Science and Engineering, Shanghai University, Shanghai 200444 (China); UCCS: Unite de Catalyse et de Chimie du Solide - UMR CNRS 8181, ENSCL, Batiment C7, BP 90108, 59652 Villeneuve d' Ascq Cedex (France); Zhen Qiang, E-mail: zhenqiang@263.ne [Nano-science and Nano-technology Research Center, School of Materials Science and Engineering, Shanghai University, Shanghai 200444 (China); Drache, Michel; Rubbens, Annick; Vannier, Rose-Noelle [UCCS: Unite de Catalyse et de Chimie du Solide - UMR CNRS 8181, ENSCL, Batiment C7, BP 90108, 59652 Villeneuve d' Ascq Cedex (France)

2010-04-02

(Bi{sub 2}O{sub 3}){sub 0.75}(Dy{sub 2}O{sub 3}){sub 0.25} nanopowder was prepared by reverse chemical titration co-precipitation method. The reaction mechanism during the precipitation process was discussed by thermodynamic analysis. Thermal decomposition behavior of the precursor was investigated using X-ray diffractometry and TG-MS analysis. The precursor was calcined at 500 {sup o}C for 3 h to obtain (Bi{sub 2}O{sub 3}){sub 0.75}(Dy{sub 2}O{sub 3}){sub 0.25} nanopowder. Using the nanopowder, pellets with relative density higher than 94% were obtained at 700 {sup o}C for 2 h by pressureless sintering, and the grains remained at the nano-scale with size of 72 nm.
Lu{sub 2}O{sub 3}:Tb,Hf storage phosphor

Energy Technology Data Exchange (ETDEWEB)

Kulesza, Dagmara; Trojan-Piegza, Joanna [Faculty of Chemistry, University of Wroclaw, 14 F. Joliot-Curie Street, 50-383 Wroclaw (Poland); Zych, Eugeniusz, E-mail: zych@wchuwr.p [Faculty of Chemistry, University of Wroclaw, 14 F. Joliot-Curie Street, 50-383 Wroclaw (Poland)

2010-03-15

Lu{sub 2}O{sub 3}:Tb,Hf ceramics containing 0.1% of Tb and 0-1.5% of Hf were prepared in reducing atmosphere at 1700 {sup o}C and their thermoluminescence properties were systematically studied. For comparison Tb,Ca co-doped specimen was also fabricated and investigated. The Tb,Hf ceramics shows basically a single TL band located around 180 {sup o}C as found with heating rate of 15 {sup o}C/min. Ceramics singly doped with Tb show complex TL glow curves indicating the presence of traps of very different depths. On the other hand Tb,Ca co-doping is beneficial for the development of shallow traps with the main TL band around 70 {sup o}C. Hence, the aliovalent impurities, Ca{sup 2+} and Hf{sup 4+}, strongly influenced the traps structure in Lu{sub 2}O{sub 3}:Tb ceramics, each of them in its own specific way. Isothermal decay of Lu{sub 2}O{sub 3}:Tb,Hf at 185 {sup o}C was recorded and its shape suggest that multiple hole trapping occurs in the Lu{sub 2}O{sub 3}:Tb,Hf ceramics. Due to the different traps depths the Lu{sub 2}O{sub 3}:Tb,Hf ceramics possess properties typical for storage phosphors, while Lu{sub 2}O{sub 3}:Tb,Ca is a persistent luminescent material rather.
Low operating voltage InGaZnO thin-film transistors based on Al{sub 2}O{sub 3} high-k dielectrics fabricated using pulsed laser deposition

Energy Technology Data Exchange (ETDEWEB)

Geng, G. Z.; Liu, G. X.; Zhang, Q.; Shan, F. K. [Qingdao University, Qingdao (China); DongEui University, Busan (Korea, Republic of); Lee, W. J.; Shin, B. C. [DongEui University, Busan (Korea, Republic of); Cho, C. R. [Pusan National University, Busan (Korea, Republic of)

2014-05-15

Low-voltage-driven amorphous indium-gallium-zinc-oxide (IGZO) thin-film transistors (TFTs) with an Al{sub 2}O{sub 3} dielectric were fabricated on a Si substrate by using pulsed laser deposition. Both Al{sub 2}O{sub 3} and IGZO thin films are amorphous, and the thin films have very smooth surfaces. The Al{sub 2}O{sub 3} gate dielectric exhibits a very low leakage current density of 1.3 x 10{sup -8} A/cm{sup 2} at 5 V and a high capacitance density of 60.9 nF/cm{sup 2}. The IGZO TFT with a structure of Ni/IGZO/Al{sub 2}O{sub 3}/Si exhibits high performance with a low threshold voltage of 1.18 V, a high field effect mobility of 20.25 cm{sup 2}V{sup -1}s{sup -1}, an ultra small subthreshold swing of 87 mV/decade, and a high on/off current ratio of 3 x 10{sup 7}.
Influence of Al{sub 2}O{sub 3} addition on microstructure and mechanical properties of 3YSZ-Al{sub 2}O{sub 3} composites

Energy Technology Data Exchange (ETDEWEB)

Abden, Md. Jaynul [International Islamic Univ., Chittagong (Bangladesh). Dept. of Electrical and Electronic Engineering; Afroze, Jannatul Dil [Noakhali Science and Technology Univ. (Bangladesh). Faculty of Science and Engineering; Gafur, Md. Abdul [Bangladesh Council of Scientific and Industrial Research, Dhaka (Bangladesh). Pilot Plant and Process Development Centre; Chowdhury, Faruque-Uz-Zaman [Chittagong University of Engineering and Technology (Bangladesh). Dept. of Physics

2015-07-01

The effect of the amount of Al{sub 2}O{sub 3} content on microstructure, tetragonal phase stability and mechanical properties of 3YSZ-Al{sub 2}O{sub 3} composites are investigated in this study. The ceramic composites are obtained by means of uniaxial compacting at 210 MPa and green compacts are sintered at 1550 C for 3 h in air. The monoclinic zirconia (m-ZrO{sub 2}) phase has completely been transformed into tetragonal zirconia (t-ZrO{sub 2}) phase with corresponding higher Al{sub 2}O{sub 3} content. The t-ZrO{sub 2} grains induce transgranular fracture mode that has contribution in improvement of fracture toughness. The maximum flexural strength of 340 MPa, Vickers hardness value of 14.31 GPa and fracture toughness of 5.1 MPa x m{sup 1/2} in the composition containing 40 wt.-% Al{sub 2}O{sub 3} is attributed to the microstructure with t-ZrO{sub 2} grains as inter- and intragranular particles in the Al{sub 2}O{sub 3} grains, which makes it suitable for dental applications.
Systems Li[sub 2]B[sub 4]O[sub 7] (Na[sub 2]B[sub 4]O[sub 7], K[sub 2]B[sub 4]O[sub 7])-N[sub 2]H[sub 3]H[sub 4]OH-H[sub 2]O at 25 deg C. Sistemy Li[sub 2]B[sub 4]O[sub 7] (Na[sub 2]B[sub 4]O[sub 7], K[sub 2]B[sub 4]O[sub 7])-N[sub 2]H[sub 3]H[sub 4]OH-H[sub 2]O pri 25 grad S

Energy Technology Data Exchange (ETDEWEB)

Skvortsov, V G; Sadetdinov, Sh V; Akimov, V M; Mitrasov, Yu N; Petrova, O V; Klopov, Yu N [Chuvashskij Gosudarstvennyj Pedagogicheskij Inst., Cheboksary (Russian Federation) Universitet Druzhby Narodov, Moscow (Russian Federation)

1994-02-01

Phase equilibriums in the Li[sub 2]B[sub 4]O[sub 7] (Na[sub 2]B[sub 4]O[sub 7], K[sub 2]B[sub 4]O[sub 7])-N[sub 2]H[sub 3]H[sub 4]OH-H[sub 2]O systems were investigated by methods of isothermal solubility, refractometry and PH-metry at 25 deg C for the first time. Lithium and sodium tetraborates was established to form phases of changed composition mM[sub 2]B[sub 4]O[sub 7][center dot]nN[sub 2]H[sub 3]C[sub 2]H[sub 4]OH[center dot]XH[sub 2]O, where M=Li, Na with hydrazine ethanol. K[sub 2]B[sub 4]O[sub 7][center dot]4H[sub 2]O precipitates in solid phase in the case of potassium salt. Formation of isomorphous mixtures was supported by X-ray diffraction and IR spectroscopy methods.
Syntheses and structural characterization of vanado-tellurites and vanadyl-selenites: SrVTeO{sub 5}(OH), Cd{sub 2}V{sub 2}Te{sub 2}O{sub 11}, Ca{sub 3}VSe{sub 4}O{sub 13}·H{sub 2}O and Ba{sub 2}VSe{sub 3}O{sub 10}

Energy Technology Data Exchange (ETDEWEB)

Konatham, Satish; Vidyasagar, Kanamaluru, E-mail: kvsagar@iitm.ac.in

2017-05-15

Four new quaternary vanado-tellurites and vanadyl-selenites, namely, SrVTeO{sub 5}(OH)(1), Cd{sub 2}V{sub 2}Te{sub 2}O{sub 11}(2), Ca{sub 3}VSe{sub 4}O{sub 13}·H{sub 2}O(3) and Ba{sub 2}VSe{sub 3}O{sub 10}(4) have been synthesized and structurally characterized by single crystal X-ray diffraction. The oxidation state of vanadium is +5 in tellurites 1 and 2 and +4 in selenites 3 and 4. The structures of SrVTeO{sub 5}(OH)(1) and Cd{sub 2}V{sub 2}Te{sub 2}O{sub 11}(2) compounds consist of (VTeO{sub 5}(OH)){sup 2-} and (V{sub 2}Te{sub 2}O{sub 11}){sup 4-}anionic chains respectively, which are built from tetrahedral VO{sub 4} and disphenoidal TeO{sub 4} moieties. Similarly the structures of Ca{sub 3}VSe{sub 4}O{sub 13}·H{sub 2}O(3) and Ba{sub 2}VSe{sub 3}O{sub 10}(4) respectively contain (VSe{sub 2}O{sub 7}){sup 2-} and (VSe{sub 3}O{sub 10}){sup 4-} anionic chains, which are made up of octahedral VO{sub 6} and pyramidal SeO{sub 3} units. Compounds 1 and 3 have been characterized by thermogravimetric and infrared spectroscopic methods. Compounds 1 and 2 are wide band gap semiconductors. - Graphical abstract: Ca{sub 3}VSe{sub 4}O{sub 13}·H{sub 2}O and Ba{sub 2}VSe{sub 3}O{sub 10} compounds contain (VSe{sub 2}O{sub 7}){sup 2-} and (VSe{sub 3}O{sub 10}){sup 4-} chains. - Highlights: • Four new vanado-tellurites and vanadyl-selenites are synthesized. • Their structural features are different. • The vanado-tellurites are wide band gap semiconductors.
Reef coral δ18O thermometer in Hainan island waters, south China sea

International Nuclear Information System (INIS)

He Xuexian; Peng Zicheng; Wang Zhaorong; Huo Weiguo; Tan Jun; Nie Baofu; Chen Tegu; Zhong Jinliang

2000-01-01

An 18-year-long (1981-1998) study was conducted in Hainan Island waters (22 degree 22'N, 110 degree 39'E) to determine the relationship between δ 18 O in skeletal aragonite carbonate and sea surface temperature (SST) in porites lutea of reef-building corals. δ 18 O values in skeletal aragonite carbonate were measured by means of mass spectrometry. Coral samples grew at 5 m depth at Longwan Bay. Monthly measurements of the SST from 1960 to 1998 were taken at Qinglan Bay adjacent to the place of the collected samples. The thermometer shows that SST = -4.16 δ 18 O PDB + 4.9 (r = 0.80) and dδ 18 O/dT = -0.24 per mil/degree C. The δ 18 O thermometer is strongly influenced by the rainfall and runoff. Using the thermometer, the SST in the past hundred years with monthly resolution will be reconstructed and the climatic change in the northern area of South China Sea will be hind cast

Characteristics of surface O{sub 3} over Qinghai Lake area in Northeast Tibetan Plateau, China

Energy Technology Data Exchange (ETDEWEB)

Shen, Zhenxing, E-mail: zxshen@mail.xjtu.edu.cn [Department of Environmental Sciences and Engineering, Xi' an Jiaotong University, Xi' an (China); Key Lab of Aerosol, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi' an (China); Cao, Junji [Key Lab of Aerosol, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi' an (China); Zhang, Leiming [Air Quality Research Division, Environment Canada, Toronto (Canada); Zhao, Zhuzi [Key Lab of Aerosol, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi' an (China); Dong, Jungang [School of Architecture, Xi' an University of Architecture and Technology, Xi' an 710055 (China); Wang, Linqing [Department of Environmental Sciences and Engineering, Xi' an Jiaotong University, Xi' an (China); Wang, Qiyuan; Li, Guohui; Liu, Suixin [Key Lab of Aerosol, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi' an (China); Zhang, Qian [Department of Environmental Sciences and Engineering, Xi' an Jiaotong University, Xi' an (China)

2014-12-01

Surface O{sub 3} was monitored continuously during Aug. 12, 2010 to Jul. 21, 2011 at a high elevation site (3200 m above sea level) in Qinghai Lake area (36°58′37″N, 99°53′56″E) in Northeast Tibetan Plateau, China. Daily average O{sub 3} ranged from 21.8 ppbv to 65.3 ppbv with an annual average of 41.0 ppbv. Seasonal average of O{sub 3} followed a decreasing order of summer > autumn > spring > winter. Diurnal variations of O{sub 3} showed low concentrations during daytime and high concentrations during late night and early morning. An intensive campaign was also conducted during Aug. 13–31, 2010 to investigate correlations between meteorological or chemical conditions and O{sub 3}. It was found that O{sub 3} was poorly correlated with solar radiation due to the insufficient NO{sub x} in the ambient air, thus limiting O{sub 3} formation under strong solar radiation. In contrast, high O{sub 3} levels always coincided with strong winds, suggesting that stratospheric O{sub 3} and long range transport might be the main sources of O{sub 3} in this rural area. Back-trajectory analysis supported this hypothesis and further indicated the transport of air masses from northwest, northeast and southeast directions. - Highlights: • Surface O{sub 3} was measured in Qinghai Lake area in Northeast Tibetan Plateau, China. • The O{sub 3} chemical formation was under a strong NOx-limited in Qinghai Lake areas. • Stratospheric O{sub 3} and transport might be the main sources of O{sub 3} in this area.
hpvPDB: An Online Proteome Reserve for Human Papillomavirus

Directory of Open Access Journals (Sweden)

Satish Kumar

2013-12-01

Full Text Available Human papillomavirus (HPV infection is the leading cause of cancer mortality among women worldwide. The molecular understanding of HPV proteins has significant connotation for understanding their intrusion in the host and designing novel protein vaccines and anti-viral agents, etc. Genomic, proteomic, structural, and disease-related information on HPV is available on the web; yet, with trivial annotations and more so, it is not well customized for data analysis, host-pathogen interaction, strain-disease association, drug designing, and sequence analysis, etc. We attempted to design an online reserve with comprehensive information on HPV for the end users desiring the same. The Human Papillomavirus Proteome Database (hpvPDB domiciles proteomic and genomic information on 150 HPV strains sequenced to date. Simultaneous easy expandability and retrieval of the strain-specific data, with a provision for sequence analysis and exploration potential of predicted structures, and easy access for curation and annotation through a range of search options at one platform are a few of its important features. Affluent information in this reserve could be of help for researchers involved in structural virology, cancer research, drug discovery, and vaccine design.
Effect of Y{sub 2}O{sub 3} addition to Rh/Al{sub 2}O{sub 3} catalysts on the autothermal reforming of methane; Efeito da adicao de Y{sub 2}O{sub 3} a catalisadores de Rh/Al{sub 2}O{sub 3} na reforma autotermica do metano

Energy Technology Data Exchange (ETDEWEB)

Ribeiro, Vanessa Monteiro; Cardoso, Gabriel Alexandre Lima; Coutinho, Ana Carla da S. Lomba S.; Passos, Fabio Barboza [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Dept. de Engenharia Quimica e de Petroleo. Lab. de Reatores, Cinetica e Catalise (RECAT)]. E-mail: vanessafisqui@yahoo.com.br

2008-07-01

In this work, the effect of the addition of Y{sub 2}O{sub 3} (with 2%, 5% and 10% weight content) on Rh/{alpha}-Al{sub 2}O{sub 3} catalysts in the autothermal reforming reaction of methane to the production of hydrogen for fuel cells was investigated. The catalysts were characterized by the following techniques: N{sub 2} adsorption, H{sub 2} chemisorption, X-ray diffraction (XRD) and cyclohexane dehydrogenation reaction. The catalysts were also evaluated in the reaction of autothermal reforming. The catalyst with higher Y{sub 2}O{sub 3} content showed the best results both in the cyclohexane dehydrogenation rate and in the conversion of methane. (author)
Synthesis of nanostructured solid-state phases of V{sub 7}O{sub 16} and V{sub 2}O{sub 5} compounds for ppb-level detection of ammonia

Energy Technology Data Exchange (ETDEWEB)

Huotari, J., E-mail: joni.huotari@ee.oulu.fi [Faculty of Information Technology and Electrical Engineering, P.O. Box 4500, FIN-90014, University of Oulu (Finland); Lappalainen, J. [Faculty of Information Technology and Electrical Engineering, P.O. Box 4500, FIN-90014, University of Oulu (Finland); Eriksson, J.; Bjorklund, R. [Department of Physics, Chemistry and Biology, Linköping University, SE-581 83, Linköping (Sweden); Heinonen, E. [Center of Microscopy and Nanotechnology, Erkki Koiso-Kanttilankatu 3, Tietotalo 1, Linnanmaa, FIN-90570, Oulu (Finland); Miinalainen, I. [Biocenter Oulu, P.O. Box 5000, FI-90014, University of Oulu (Finland); Puustinen, J. [Faculty of Information Technology and Electrical Engineering, P.O. Box 4500, FIN-90014, University of Oulu (Finland); Lloyd Spetz, A. [Faculty of Information Technology and Electrical Engineering, P.O. Box 4500, FIN-90014, University of Oulu (Finland); Department of Physics, Chemistry and Biology, Linköping University, SE-581 83, Linköping (Sweden)

2016-08-05

Solid state phase of V{sub 7}O{sub 16} with separate V{sub 2}O{sub 5} phase were fabricated by pulsed laser deposition. The crystal structure and symmetry of the deposited films were studied with X-ray diffraction and Raman spectroscopy, respectively. Rietveld analysis was performed to the X-ray diffraction measurement results. The surface potentials and morphologies of the films were studied with atomic force microscopy, and microstructure of the thin films was analysed by transmission electron microscopy. Raman spectroscopy and Rietveld refinement results confirmed that the thin-film crystal structures varied between orthorombic V{sub 2}O{sub 5} phase and another phase, triclinic V{sub 7}O{sub 16}, previously found only in the walls of vanadium oxide nanotubes (VO{sub x}-NT), bound together with organic amine. We have earlier presented the first results of stable and pure metal-oxide solid-state phase of V{sub 7}O{sub 16} manufactured from ceramic V{sub 2}O{sub 5} target. Here we show more detailed study of these structures. The microstructure studies showed a variation on the porosity of the films according to crystal structures and also some fibre-like nanostructures were found in the films. The surface morphology depended strongly on the crystal structure and the surface potential studies showed ∼50 meV difference in the work function values between the phases. Compounds were found to be extremely sensitive towards ammonia, NH{sub 3}, down to ∼40 ppb concentrations, and have shown to have the stability and selectivity to control the Selective Catalytic Reduction process, where nitrogen oxides are reduced by ammonia in, e.g. diesel exhausts. - Highlights: • The triclinic V{sub 7}O{sub 16} phase is proven to exist in solid state thin-film form. • The existence of V{sub 7}O{sub 16} in thin-film form is proven by several methods. • The structure of mixed V{sub 7}O{sub 16} and V{sub 2}O{sub 5} is proven to be sensitive to NH{sub 3} at ppb-level.
Fe{sub 2} O{sub 3} addition influence on the Sn O{sub 2}.Co O.Nb{sub 2} O{sub 5} varistors system; Influencia da adicao de Fe{sub 2} O{sub 3} no sistema varistor Sn O{sub 2}.Co O.Nb{sub 2} O{sub 5}

Energy Technology Data Exchange (ETDEWEB)

Antunes, A.C.; Antunes, S.R.M. [Universidade Estadual de Ponta Grossa, PR (Brazil). Dept. de Quimica; Castilhos, J.G.R.; Pianaro, S.R.; Zara, J.A. [Universidade Estadual de Ponta Grossa, PR (Brazil). Dept. de Engenharia dos Materiais; Longo, E. [Sao Carlos Univ., SP (Brazil). Dept. de Quimica; Varela, J.A. [UNESP, Araraquara, SP (Brazil). Inst. de Quimica

1997-12-31

The effect 0.05 to 0.30 mol% Fe{sub 2} 0{sub 3} addition on the electrical and microstructural properties of ternary varistor system composed by tin oxide, niobium oxide and cobaltum oxide was studied in this work. The samples were sintered at 1300 deg C for two hours. The characterizations were performed by Vxi measurements, scanning electron microscopy and X - ray diffraction. The Fe{sub 2} O{sub 3} additions up to 0,10% increased the {alpha} values breakdown electric fields (E{sub r}) and it was observed that the barrier voltage (v{sub b}) depends on the chemical composition. The second phase had high concentration of iron that precipitated in the grain boundaries and inhibited the grain growth during sintering. Fe{sub 2} O{sub 3} concentrations upper 0,10 mol% were deleterious for electrical properties of the ceramics. (author) 7 refs., 3 figs., 4 tabs.
ALD Produced B{sub 2}O{sub 3}, Al{sub 2}O{sub 3} and TiO{sub 2} Coatings on Gd{sub 2}O{sub 3} Burnable Poison Nanoparticles and Carbonaceous TRISO Coating Layers

Energy Technology Data Exchange (ETDEWEB)

Weimer, Alan

2012-11-26

This project will demonstrate the feasibility of using atomic layer deposition (ALD) to apply ultrathin neutron-absorbing, corrosion-resistant layers consisting of ceramics, metals, or combinations thereof, on particles for enhanced nuclear fuel pellets. Current pellet coating technology utilizes chemical vapor deposition (CVD) in a fluidized bed reactor to deposit thick, porous layers of C (or PyC) and SiC. These graphitic/carbide materials degrade over time owing to fission product bombardment, active oxidation, thermal management issues, and long-term irradiation effects. ALD can be used to deposit potential ceramic barrier materials of interest, including ZrO{sub 2}, Y{sub 2}O{sub 3}:ZrO{sub 2} (YSZ), Al{sub 2}O{sub 3}, and TiO{sub 2}, or neutron-absorbing materials, namely B (in BN or B{sub 2}O{sub 3}) and Gd (in Gd{sub 2}O{sub 3}). This project consists of a two-pronged approach to integrate ALD into the next-generation nuclear plant (NGNP) fuel pellet manufacturing process:
Influence of Fe{sub 3}O{sub 4}/Fe-phthalocyanine decorated graphene oxide on the microwave absorbing performance

Energy Technology Data Exchange (ETDEWEB)

Li, Jingwei; Wei, Junji; Pu, Zejun; Xu, Mingzhen; Jia, Kun, E-mail: jiakun@uestc.edu.cn; Liu, Xiaobo, E-mail: liuxb@uestc.edu.cn

2016-02-01

Novel graphene oxide@Fe{sub 3}O{sub 4}/iron phthalocyanine (GO@Fe{sub 3}O{sub 4}/FePc) hybrid materials were prepared through a facile one-step solvothermal method with graphene oxide (GO) sheets as template in ethylene glycol. The morphology and structure of the hybrid materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectrophotometer (FTIR) and X-ray diffraction (XRD), respectively. The results indicated that the monodispersed Fe{sub 3}O{sub 4}/FePc hybrid microspheres were uniformly self-assembled along the surface of GO sheets through electrostatic attraction and the morphology can be tuned by controlling the amount of 4,4′-bis(3,4-dicyanophenoxy)biphenyl (BPH). As the BPH content increases, magnetization measurement of the GO@Fe{sub 3}O{sub 4}/FePc hybrid materials showed that the coercivity increased, while saturation magnetizations decreased. Electromagnetic properties of the hybrid materials were measured in the range of 0.5–18.0 GHz. The microwave absorbing performance enhanced with the increase of BPH content and a maximum reflection loss of −27.92 dB was obtained at 10.8 GHz when the matching thickness was 2.5 mm. Therefore, the novel electromagnetic hybrid materials can be considered as potential materials in the microwave absorbing field. - Highlights: • Graphene oxide was employed to support Fe{sub 3}O{sub 4}/iron phthalocyanine hybrid particles. • The morphology and magnetic properties of obtained particles can be readily tuned. • A maximum microwave reflection loss of −27.92 dB was obtained at 10.8 GHz.
Direct Synthesis of H{sub 2}O{sub 2} over Ti-Containing Molecular Sieves Supported Gold Catalysts: A Comparative Study for In-situ-H{sub 2}O{sub 2}-ODS of Fuel

Energy Technology Data Exchange (ETDEWEB)

Zhang, Han; Song, Haiyan; Chen, Chunxia; Han, Fuqin; Hu, Shaozheng [Northeast Forestry Univ., Harbin (China); Liu, Guangliang [Univ. of Connecticut, Storrs (United States); Chen, Ping; Zhao, Zhixi [Xinjiang Normal Univ., Urumqi (China)

2013-10-15

Direct synthesis of H{sub 2}O{sub 2} and in situ oxidative desulfurization of model fuel over Au/Ti-HMS and Au/TS-1 catalysts has been comparatively investigated in water or methanol. Maximum amount (82%) of active Au{sup 0} species for H{sub 2}O{sub 2} synthesis was obtained. Au/Ti-HMS and Au/TS-1 exhibited the contrary performances in H{sub 2}O{sub 2} synthesis as CH{sub 3}OH/H{sub 2}O ratio of solvent changed. H{sub 2}O{sub 2} decomposition and hydrogenation in water was inhibited by the introduction of methanol. Effect of O{sub 2}/H{sub 2} ratio on H{sub 2}O{sub 2} concentration, H{sub 2} conversion and H{sub 2}O{sub 2} selectivity revealed a relationship between H{sub 2}O{sub 2} generation and H2 consumption. The highest dibenzothiophene removal rate (83.2%) was obtained over Au/Ti-HMS in methanol at 1.5 of O{sub 2}/H{sub 2} ratio and 60 .deg. C. But removal of thiophene over Au/TS-1 should be performed in water without heating to obtain a high removal rate (61.3%). Meanwhile, H{sub 2} conversion and oxidative desulfurization selectivity of H{sub 2} were presented.
Geochemistry of the stable isotopes of silicon

Energy Technology Data Exchange (ETDEWEB)

Douthitt, C B [California Inst. of Tech., Pasadena (USA). Div. of Geological and Planetary Sciences

1982-08-01

One hundred thirty two new measurements of the relative abundances of the stable isotopes of silicon in terrestrial materials are presented. The total variation of delta/sup 30/Si found is 6.2 parts per thousand, centered on the mean of terrestrial mafic and ultramafic igneous rocks, delta/sup 30/Si = -0.4 parts per thousand. Igneous rocks show limited variation; coexisting minerals exhibit small, systematic silicon isotopic fractionations that are roughly 1/3 the magnitude of concomitant oxygen isotopic fractionations at 1150/sup 0/C. In both igneous minerals and rocks, delta/sup 30/Si shows a positive correlation with silicon content, as does delta/sup 18/O. Opal from both sponge spicules and sinters is light, with delta/sup 30/Si = -2.3 and -1.4 parts per thousand respectively. Large delta/sup 30/Si values of both positive and negative sign are reported for the first time from clay minerals, opaline phytoliths, and authigenic quartz. All highly fractionated samples were precipitated from solution at low temperatures; however, aqueous silicon is not measurably fractionated relative to quartz at equilibrium. A kinetic isotope fractionation of approximately 3.5 parts per thousand is postulated to occur during the low temperature precipitation of opal and, possibly, poorly ordered phyllosilicates, with the silicate phase being enriched in /sup 28/Si. This fractionation, coupled with a Rayleigh precipitation model, is capable of explaining most non-magmatic delta/sup 30/Si variations.
Lithium insertion in V{sub 2}O{sub 5}, M{sub x}V{sub 2}O{sub 5} (M = Fe, Cr, Al, La) mixed oxides; Insertion du lithium dans les oxydes mixtes de V{sub 2}O{sub 5}, M{sub x}V{sub 2}O{sub 5} (M = Fe, Cr, Al, La)

Energy Technology Data Exchange (ETDEWEB)

Gregoire, G.; Pecquenard, B.; Baffier, N. [Centre National de la Recherche Scientifique (CNRS), 75 - Paris (France). Laboratoire de Chimie Appliquee de l`Etat Solide; Soudan, P.; Farcy, J.; Pereira-Ramos, J.P. [Centre National de la Recherche Scientifique (CNRS), 94 - Ivry-sur-Seine (France). Laboratoire d`Electrochimie Catalyse et Synthese Organique

1996-12-31

V{sub 2}O{sub 5} based compounds are interesting low potential materials for rechargeable cathodes of lithium electrochemical generators. However, the ionic conductivity and the reversibility of electrochemical cycling of V{sub 2}O{sub 5} are limited by the possibilities of lithium insertion. This work shows that the doping of vanadium pentoxide by a M{sup 3+} trivalent transition element (M Fe, Al, Cr or La) allows to intercalate a more important amount of lithium and to improve the behaviour of the material during cycling. These materials of M{sub 0.11}V{sub 2}O{sub 5.16} formula are obtained by sol-gel synthesis. the electrochemical study of the Fe compound has shown that it is a mixed oxide with a behaviour similar to V{sub 2}O{sub 5}. The maximum capacity is of about 2 F/mole in the case of Fe, Al and Cr compounds and of about 1.7 F/mole in the case of La. The structural evolution of the Fe compound has been followed during the chemical insertion of Li and the same succession of phases ({alpha}, {epsilon}, {delta} and {gamma}) is observed as in Li{sub x}V{sub 2}O{sub 5} compounds but with a delay. The occurrence of the {gamma} phase, in particular, which is involved in recharging problems is delayed thanks to the (Fe-O){sub n} chains perpendicular to the (V{sub 2}O{sub 5}){sub n} layers. Abstract only. (J.S.) 3 refs.
Lithium insertion in V{sub 2}O{sub 5}, M{sub x}V{sub 2}O{sub 5} (M = Fe, Cr, Al, La) mixed oxides; Insertion du lithium dans les oxydes mixtes de V{sub 2}O{sub 5}, M{sub x}V{sub 2}O{sub 5} (M = Fe, Cr, Al, La)

Energy Technology Data Exchange (ETDEWEB)

Gregoire, G; Pecquenard, B; Baffier, N [Centre National de la Recherche Scientifique (CNRS), 75 - Paris (France). Laboratoire de Chimie Appliquee de l` Etat Solide; Soudan, P; Farcy, J; Pereira-Ramos, J P [Centre National de la Recherche Scientifique (CNRS), 94 - Ivry-sur-Seine (France). Laboratoire d` Electrochimie Catalyse et Synthese Organique

1997-12-31

V{sub 2}O{sub 5} based compounds are interesting low potential materials for rechargeable cathodes of lithium electrochemical generators. However, the ionic conductivity and the reversibility of electrochemical cycling of V{sub 2}O{sub 5} are limited by the possibilities of lithium insertion. This work shows that the doping of vanadium pentoxide by a M{sup 3+} trivalent transition element (M Fe, Al, Cr or La) allows to intercalate a more important amount of lithium and to improve the behaviour of the material during cycling. These materials of M{sub 0.11}V{sub 2}O{sub 5.16} formula are obtained by sol-gel synthesis. the electrochemical study of the Fe compound has shown that it is a mixed oxide with a behaviour similar to V{sub 2}O{sub 5}. The maximum capacity is of about 2 F/mole in the case of Fe, Al and Cr compounds and of about 1.7 F/mole in the case of La. The structural evolution of the Fe compound has been followed during the chemical insertion of Li and the same succession of phases ({alpha}, {epsilon}, {delta} and {gamma}) is observed as in Li{sub x}V{sub 2}O{sub 5} compounds but with a delay. The occurrence of the {gamma} phase, in particular, which is involved in recharging problems is delayed thanks to the (Fe-O){sub n} chains perpendicular to the (V{sub 2}O{sub 5}){sub n} layers. Abstract only. (J.S.) 3 refs.
ORF Alignment: NC_002945 [GENIUS II[Archive

Lifescience Database Archive (English)

Full Text Available ... Crystal Structure Of A Type Iii Polyketide Synthase ... Pks18 From Mycobacterium Tuberculosis... Type Iii Polyketide Synthase ... Pks18 From Mycobacterium Tuberculosis pdb|1TED|A Chain ... A..., Crystal Structure Of A Type Iii Polyketide Synthase ... Pks18 From Mycobacterium Tuberculosis emb|C... pdb|1TED|C Chain ... C, Crystal Structure Of A Type Iii Polyketide Synthase ... Pks18 From Mycobacterium Tuberculos...is pdb|1TED|B Chain ... B, Crystal Structure Of A
ORF Alignment: NC_002755 [GENIUS II[Archive

Lifescience Database Archive (English)

Full Text Available ... Crystal Structure Of A Type Iii Polyketide Synthase ... Pks18 From Mycobacterium Tuberculosis... Type Iii Polyketide Synthase ... Pks18 From Mycobacterium Tuberculosis pdb|1TED|A Chain ... A..., Crystal Structure Of A Type Iii Polyketide Synthase ... Pks18 From Mycobacterium Tuberculosis emb|C... pdb|1TED|C Chain ... C, Crystal Structure Of A Type Iii Polyketide Synthase ... Pks18 From Mycobacterium Tuberculos...is pdb|1TED|B Chain ... B, Crystal Structure Of A
ORF Alignment: NC_000962 [GENIUS II[Archive

Lifescience Database Archive (English)

Full Text Available ... Crystal Structure Of A Type Iii Polyketide Synthase ... Pks18 From Mycobacterium Tuberculosis... Type Iii Polyketide Synthase ... Pks18 From Mycobacterium Tuberculosis pdb|1TED|A Chain ... A..., Crystal Structure Of A Type Iii Polyketide Synthase ... Pks18 From Mycobacterium Tuberculosis emb|C... pdb|1TED|C Chain ... C, Crystal Structure Of A Type Iii Polyketide Synthase ... Pks18 From Mycobacterium Tuberculos...is pdb|1TED|B Chain ... B, Crystal Structure Of A
Novel oxide buffer approach for GaN integration on Si(111) platform through Sc{sub 2}O{sub 3}/Y{sub 2}O{sub 3} bi-layer

Energy Technology Data Exchange (ETDEWEB)

Tarnawska, Lidia

2012-12-19

Motivation: Preparation of GaN virtual substrates on large-scale Si wafers is intensively pursued as a cost-effective approach for high power/high frequency electronics (HEMT's etc.) and optoelectronic applications (LED, LASER). However, the growth of high quality GaN layers on Si is hampered by several difficulties mainly related to a large lattice mismatch (-17%) and a huge difference in the thermal expansion coefficient (56%). As a consequence, GaN epitaxial layers grown on Si substrates show a high number of defects (threading dislocations etc.), which severely deteriorate the overall quality of the GaN films. Additionally, due to the different thermal expansion coefficients of the substrate and the film, um-thick GaN layers crack during post-growth cooling. To solve these integration problems, different semiconducting (e.g. AlN, GaAs, ZnO, HfN) and insulating (e.g. Al{sub 2}O{sub 3}, MgO, LiGaO{sub 2}) buffer layers, separating the Si substrate from the GaN film, are applied. Goal: In this thesis, a novel buffer approach for the integration of GaN on Si is proposed and investigated. The new approach employs Sc{sub 2}O{sub 3}/Y{sub 2}O{sub 3} bilayer templates as a step-graded buffer to reduce the lattice mismatch between GaN and the Si(111) substrate. According to the bulk crystal lattices, since the Y{sub 2}O{sub 3} has an in-plane lattice misfit of -2% to Si, Sc{sub 2}O{sub 3} -7% to Y{sub 2}O{sub 3}, the lattice misfit between GaN and the substrate can be theoretically reduced by about 50% from -17% (GaN/Si) to -8% (GaN/Sc{sub 2}O{sub 3}). Experimental: The GaN/Sc{sub 2}O{sub 3}/Y{sub 2}O{sub 3}/Si(111) heterostructures are prepared in a multichamber molecular beam epitaxy system on 4 inch Si(111) wafers. In order to obtain complete information on the structural quality of the oxide buffer as well as the GaN layer, synchrotron- and laboratory-based X-ray diffraction, transmission electron microscopy and photoluminescence measurements are performed. The
Synthesis and characterization of the new copper indium phosphate Cu{sub 8}In{sub 8}P{sub 4}O{sub 30}

Energy Technology Data Exchange (ETDEWEB)

Hanzelmann, Christian; Weimann, Iren; Feller, Joerg [Hochschule fuer Technik und Wirtschaft Dresden, Friedrich-List-Platz 1, 01069 Dresden (Germany); Zak, Zdirad [Masaryk University, Kotlarska 267/2, 61137 Brno (Czech Republic)

2014-01-15

The system CuO/In{sub 2}O{sub 3}/P{sub 2}O{sub 5} has been investigated using solid state reaction between CuO, In{sub 2}O{sub 3} and (NH{sub 4}){sub 2}HPO{sub 4} in silica glass crucibles at 900 C. The powder samples were characterized by X-ray diffraction, thermal analysis and FT-IR spectroscopy. Orange single crystals of the new quaternary phase were achieved by the process of crystallization with mineralizers in sealed silica glass ampoules. They were then analyzed with EDX and single-crystal X-ray analysis in which the composition Cu{sub 8}In{sub 8}P{sub 4}O{sub 30} with the triclinic space group P anti 1 (No 2) with a = 7,2429(14) Aa, b = 8,8002(18) Aa, c = 10,069(2) Aa, α = 103,62(3) , β = 106,31(3) , γ = 101,55(3) and Z = 1 was found. The three-dimensional framework consists of [InO{sub 6}] octahedra and distorted [CuO{sub 6}] octahedra, overcaped [InO{sub 7}] prisms and [PO{sub 4}] tetrahedra, also trigonal [(CuIn)O{sub 5}] bipyramids and distorted [(CuIn)O{sub 6}] octahedra, where copper and indium are partly exchanged against each other. Cu{sub 8}In{sub 8}P{sub 4}O{sub 30} exhibits an incongruent melting point at 1023 C. (Copyright copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Direct synthesis of Sb{sub 2}O{sub 3} nanoparticles via hydrolysis-precipitation method

Energy Technology Data Exchange (ETDEWEB)

Hu, Yuehua [Department of Inorganic Materials, School of Resources Processing and Bioengineering, Central South University, Changsha 410083 (China); Zhang, Huihui [Department of Inorganic Materials, School of Resources Processing and Bioengineering, Central South University, Changsha 410083 (China); Yang, Huaming [Department of Inorganic Materials, School of Resources Processing and Bioengineering, Central South University, Changsha 410083 (China)]. E-mail: hmyang@mail.csu.edu.cn

2007-01-31

Antimony oxide (Sb{sub 2}O{sub 3}) has wide applications as conductive materials, effective catalyst, functional filler and optical materials. Nanocrystalline Sb{sub 2}O{sub 3} has been successfully synthesized by hydrolysis-precipitation method. The samples were characterized by means of transmission electron microscopy (TEM), high-resolution TEM (HRTEM) images, X-ray diffraction (XRD) and differential thermal analysis (DTA). The average crystal size of the Sb{sub 2}O{sub 3} nanoparticles increases with increasing the reaction temperature. TEM image of the as-synthesized nanocrystalline Sb{sub 2}O{sub 3} shows rod-like structure. HRTEM images indicate a preferred directional growth of the Sb{sub 2}O{sub 3} nanoparticles. The electrochemical behaviors of Sb{sub 2}O{sub 3} electrodes have been primarily investigated by cyclic voltammetry (CV) in lithium hexafluorophosphate (LiPF{sub 6}) solution. Sb{sub 2}O{sub 3} nanocrystallite phase has prominent effect on the electrochemical properties. The results indicate that nanocrystalline Sb{sub 2}O{sub 3} synthesized by hydrolysis-precipitation method shows potential application in the field of the electrode materials.
New insight into electrochemical-induced synthesis of NiAl{sub 2}O{sub 4}/Al{sub 2}O{sub 3}: Synergistic effect of surface hydroxyl groups and magnetism for enhanced adsorptivity of Pd(II)

Energy Technology Data Exchange (ETDEWEB)

Salleh, N.F.M. [Department of Chemical Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Jalil, A.A., E-mail: aishah@cheme.utm.my [Department of Chemical Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Centre of Hydrogen Energy, Institute of Future Energy, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Triwahyono, S. [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Efendi, J. [Department of Chemistry, Universitas Negeri Padang, Jl. Prof. Hamka, Air Tawar, Padang, West Sumatera (Indonesia); Mukti, R.R. [Division of Inorganic and Physical Chemistry, Faculty of Mathematics and Natural Science, Institut Teknologi Bandung, Jl Ganesha No 10, Bandung 40132 (Indonesia); Hameed, B.H. [School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia)

2015-09-15

Graphical abstract: - Highlights: • The introduction of Ni to γ-Al{sub 2}O{sub 3} by electrolysis formed NiAl{sub 2}O{sub 4} spinels and NiO. • Physical mixed of NiO with γ-Al{sub 2}O{sub 3} only produced agglomerated NiO-Ni{sup 0}. • Ni/Al{sub 2}O{sub 3}-E has remarkably higher degree of magnetism than Ni/Al{sub 2}O{sub 3}-PM. • Ni/Al{sub 2}O{sub 3}-E adsorbed Pd{sup 2+} ions more effectively (q{sub m} = 40.3 mg/g) than Ni/Al{sub 2}O{sub 3}-PM. • Pd{sup 2+} ions were adsorbed to both samples via magnetic attraction and ion exchange. - Abstract: A new promising adsorbent, Ni supported on γ-Al{sub 2}O{sub 3} was prepared in a simple electrolysis system (Ni/Al{sub 2}O{sub 3}-E) in minutes and was compared with the sample prepared by a physical mixing method (Ni/Al{sub 2}O{sub 3}-PM). The adsorbents were characterized by XRD, TEM, FTIR, {sup 27}Al MAS NMR, XPS, and VSM. The results showed that besides NiO nanoparticles, a NiAl{sub 2}O{sub 4} spinel was also formed in Ni/Al{sub 2}O{sub 3}-E during the electrolysis via the dealumination and isomorphous substitution of Ni{sup 2+} ions. In contrast, only agglomerated NiO was found in the Ni/Al{sub 2}O{sub 3}-PM. Adsorption test on removal of Pd{sup 2+} ions from aqueous solution showed that the Pd{sup 2+} ions were exchanged with the hydrogen atoms of the surface–OH groups of both adsorbents. Significantly, the Ni/Al{sub 2}O{sub 3}-E demonstrated a higher adsorption towards Pd{sup 2+} ions than Ni/Al{sub 2}O{sub 3}-PM due to its remarkably higher degree of magnetism, which came from the NiAl{sub 2}O{sub 4}. The use of 0.1 g L{sup −1} Ni/Al{sub 2}O{sub 3}-E gave the maximum monolayer adsorption capacity (q{sub m}) of 40.3 mg g{sup −1} at 303 K and pH 5. The Ni/Al{sub 2}O{sub 3}-E showed high potential for simultaneous removal of various noble and transition metal ions and could be also used repetitively without affecting the high adsorptivity for Pd{sup 2+} ions. This work may provide promising
Vaporization study on nonstoichiometric NbOsub(2+-x) by mass-spectrometric method

International Nuclear Information System (INIS)

Matsui, T.; Naito, K.

1981-01-01

The vapor pressures over nonstoichiometric NbOsub(2+-x)(s) (1.972 2 (g) and NbO(g) over nonstoichiometric NbOsub(2+-x), from which the partial molar enthalpies and entropies of oxygen were calculated as a function of O/Nb composition. The composition dependence of the partial molar enthalpy and entropy obtained suggested the existence of some kind of short-range ordering in the nonstoichiometric Nbsub(2+-x) (s) phase. The enthalpies of formation of nonstoichiometric NbOsub(2+-x) (s) were also determined as a function of composition by combining the partial molar enthalpies of oxygen with the enthalpy of formation of stoichiometric NbOsub(2.000) (s). The phase diagram around NbOsub(2+-x) at high temperatures was determined from the vaporization study. (orig.)
Nb/sub 2/Te/sub 2/O/sub 9/ and Ta/sub 2/Te/sub 2/O/sub 9/: Two new mixed oxides of Te(IV)

International Nuclear Information System (INIS)

Gaitan, M.; Jerez, A.; Pico, C.; Veiga, M.L.

1987-01-01

Nb/sub 2/Te/sub 2/O/sub 9/ and Ta/sub 2/Te/sub 2/O/sub 9/ were prepared by solid state reactions between amorphous TeO/sub 3/(s) and metallic pentoxides of Nb and Ta. A crystallographic analysis carried out by X-ray diffraction showed that these compounds are isostructural (space group: P2/sub 1//C. a = 6.883 A, b = 7.853 A, c = 14.591 A, β = 103.66 for Nb/sub 2/Te/sub 2/O/sub 9/ and a = 7.10 A, b = 7.48 A, c = 14.62 A, β = 102.9 for Ta/sub 2/Te/sub 2/O/sub 9/). The IR spectra and thermal decomposition processes of both mixed oxides were studied

PDB2CD visualises dynamics within protein structures.

Science.gov (United States)

Janes, Robert W

2017-10-01

Proteins tend to have defined conformations, a key factor in enabling their function. Atomic resolution structures of proteins are predominantly obtained by either solution nuclear magnetic resonance (NMR) or crystal structure methods. However, when considering a protein whose structure has been determined by both these approaches, on many occasions, the resultant conformations are subtly different, as illustrated by the examples in this study. The solution NMR approach invariably results in a cluster of structures whose conformations satisfy the distance boundaries imposed by the data collected; it might be argued that this is evidence of the dynamics of proteins when in solution. In crystal structures, the proteins are often in an energy minimum state which can result in an increase in the extent of regular secondary structure present relative to the solution state depicted by NMR, because the more dynamic ends of alpha helices and beta strands can become ordered at the lower temperatures. This study examines a novel way to display the differences in conformations within an NMR ensemble and between these and a crystal structure of a protein. Circular dichroism (CD) spectroscopy can be used to characterise protein structures in solution. Using the new bioinformatics tool, PDB2CD, which generates CD spectra from atomic resolution protein structures, the differences between, and possible dynamic range of, conformations adopted by a protein can be visualised.
Synthesis and characterization of In{sub 2}O{sub 3} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Ayeshamariam, A. [KhadirMohideen College, Adirampattinam (India); Kashif, M. [Universiti Malaysia Perlis, Perlis (Malaysia); Raja, S. Muthu [Vellore Institute of Technology, Vellore (India); Sivaranjani, S. [SBM College of Engineering and technology, Dindigul (India); Sanjeeviraja, C. [Alagappa University, Karaikudi (India); Bououdina, M. [University of Bahrain, Bahrain (Bahrain)

2014-01-15

Metal-oxide nanostructures have elicited increasing interest in both fundamental and applied sciences. Among metal oxide nanostructures, In{sub 2}O{sub 3} has the potential for use asa semiconductor material. This article provides details on studies carried out thus far for the synthesis and the characterization of In{sub 2}O{sub 3} nanostructures. In this research, various techniques were investigated for the fabrication of diverse and fascinating spherical shaped In{sub 2}O{sub 3} nanostructures. BrunauerEmmett-Teller (BET) analyses of the In{sub 2}O{sub 3} nanostructures through detailed refinements of the structure of the In{sub 2}O{sub 3} nanoparticles by using the Rietveld method, followed by microstructural analyses using scanning electron microscopy/ transmission electron microscopy (SEM/TEM) and a chemical composition analysis are presented and discussed. Decreasing crystallinity with an improvement in specific surface area was observed from the structural characterization. The energy dispersive analysis results showed that the as-prepared In{sub 2}O{sub 3} powder sample was stoichiometric, containing almost equal proportions of indium and oxygen. The microstructural analysis (TEM and SEM) demonstrated precise control over the diameters of the nanoparticles, which is an important advantage of the solution combustion approach.
First-principles insights on electron transport in V{sub 2}O{sub 5} nanostructures

Energy Technology Data Exchange (ETDEWEB)

Srivastava, Anurag [Advanced Materials Research Group, Computational Nanoscience and Technology Laboratory, Atal Bihari Vajpayee-Indian Institute of Information Technology and Management, Gwalior, Madhya Pradesh 474015 (India); Chandiramouli, R., E-mail: rcmoulii@gmail.com [School of Electrical and Electronics Engineering, Shanmugha Arts Science Technology and Research Academy (SASTRA) University, Tirumalaisamudram, Thanjavur, Tamil Nadu 613 401 (India)

2015-11-15

Graphical abstract: - Highlights: • Band structure and electron transport in V{sub 2}O{sub 5} nanostructure are investigated using density functional theory. • V{sub 2}O{sub 5} nanostructure exhibits semiconducting behavior. • The electron density is observed to be more in oxygen sites than in vanadium sites. • The electron transport in V{sub 2}O{sub 5} molecular device can be tuned with the applied bias voltage. - Abstract: The present report is on the electron transport properties of V{sub 2}O{sub 5} nanostructures, investigated using density functional theory. As the band structure of V{sub 2}O{sub 5} exhibits semiconducting nature, the V{sub 2}O{sub 5} nanostructures are designed as molecular device and the transport properties are studied. The density of electrons is found to be more in the oxygen sites than in vanadium sites. The device density of states shows that the density of electrons in the energy intervals depends on the applied bias voltage. The transmission spectrum gives the insight on the transport property of V{sub 2}O{sub 5} molecular device. The bias voltage drives the electrons across V{sub 2}O{sub 5} scattering region, where the transmission along V{sub 2}O{sub 5} molecular device mainly depends on the bias voltage. The findings of the present work give insights to fine-tune the transport property of V{sub 2}O{sub 5} molecular device upon varying the bias voltage.
The compositional, structural, and magnetic properties of a Fe{sub 3}O{sub 4}/Ga{sub 2}O{sub 3}/GaN spin injecting hetero-structure grown by metal-organic chemical vapor deposition

Energy Technology Data Exchange (ETDEWEB)

Xu, Zhonghua; Huang, Shimin [Nanjing National Laboratory of Microstructures and School of Electronic Science and Engineering, Nanjing University, Nanjing 210023 (China); Tang, Kun, E-mail: ktang@nju.edu.cn [Nanjing National Laboratory of Microstructures and School of Electronic Science and Engineering, Nanjing University, Nanjing 210023 (China); Gu, Shulin, E-mail: slgu@nju.edu.cn [Nanjing National Laboratory of Microstructures and School of Electronic Science and Engineering, Nanjing University, Nanjing 210023 (China); Zhu, Shunming [Nanjing National Laboratory of Microstructures and School of Electronic Science and Engineering, Nanjing University, Nanjing 210023 (China); Ye, Jiandong [Nanjing National Laboratory of Microstructures and School of Electronic Science and Engineering, Nanjing University, Nanjing 210023 (China); Nanjing University Institute of Optoelectronics at Yangzhou, Yangzhou 225009 (China); Xu, Mingxiang [Department of Physics, Southeast University, Nanjing 210096 (China); Wang, Wei; Zheng, Youdou [Nanjing National Laboratory of Microstructures and School of Electronic Science and Engineering, Nanjing University, Nanjing 210023 (China)

2016-12-01

Highlights: • The Fe{sub 3}O{sub 4}/Ga{sub 2}O{sub 3}/GaN hetero-structure has been fabricated by MOCVD successfully. • The formation mechanism of different layers in sample was revealed in details. • The properties of the hetero-structure have been presented and discussed extensively. • The effect of Ga diffusion on the magnetic properties of Fe{sub 3}O{sub 4} film has been shown. - Abstract: In this article, the authors have designed and fabricated a Fe{sub 3}O{sub 4}/Ga{sub 2}O{sub 3}/GaN spin injecting hetero-structure by metal-organic chemical vapor deposition. The compositional, structural, and magnetic properties of the hetero-structure have been characterized and discussed. From the characterizations, the hetero-structure has been successfully grown generally. However, due to the unintentional diffusion of Ga ions from Ga{sub 2}O{sub 3}/GaN layers, the most part of the nominal Fe{sub 3}O{sub 4} layer is actually in the form of Ga{sub x}Fe{sub 3−x}O{sub 4} with gradually decreased x values from the Fe{sub 3}O{sub 4}/Ga{sub 2}O{sub 3} interface to the Fe{sub 3}O{sub 4} surface. Post-annealing process can further aggravate the diffusion. Due to the similar ionic radius of Ga and Fe, the structural configuration of the Ga{sub x}Fe{sub 3−x}O{sub 4} does not differ from that of pure Fe{sub 3}O{sub 4}. However, the ferromagnetism has been reduced with the incorporation of Ga into Fe{sub 3}O{sub 4}, which has been explained by the increased Yafet-Kittel angles in presence of considerable amount of Ga incorporation. A different behavior of the magnetoresistance has been found on the as-grown and annealed samples, which could be modelled and explained by the competition between the spin-dependent and spin-independent conduction channels. This work has provided detailed information on the interfacial properties of the Fe{sub 3}O{sub 4}/Ga{sub 2}O{sub 3}/GaN spin injecting hetero-structure, which is the solid basis for further improvement and application of
Effect of MnCuFe{sub 2}O{sub 4} content on magnetic and dielectric properties of poly (O-Phenylenediamine)/MnCuFe{sub 2}O{sub 4} nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Kannapiran, Nagarajan [PG and Research Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India); Muthusamy, Athianna, E-mail: muthusrkv@gmail.com [PG and Research Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India); Chitra, Palanisamy [PG and Research Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India)

2016-03-01

Poly o-phenylenediamine (PoPD)/MnCuFe{sub 2}O{sub 4} nanocomposites with three different ratios of MnCuFe{sub 2}O{sub 4} (10%, 20%, 30% w/w) were synthesized by in-situ oxidative chemical polymerization method ammonium persulphate used as oxidant, while MnCuFe{sub 2}O{sub 4} nanoparticles was prepared by auto-combustion method. The structure, morphology and magnetic properties of synthesized PoPD/MnCuFe{sub 2}O{sub 4} nanocomposites were characterized by FT-IR, UV–visible absorption spectra, X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Thermogravimetric analysis (TGA) and Vibrating sample magnetometer (VSM). FTIR spectra and XRD were confirmed the formation of the PoPD/MnCuFe{sub 2}O{sub 4} nanocomposites. The morphology of PoPD/MnCuFe{sub 2}O{sub 4} nanocomposites is visualized through SEM and TEM. The spherical morphology of the PoPD was confirmed using SEM analysis. Dielectric properties of PoPD/MnCuFe{sub 2}O{sub 4} nanocomposites at different temperatures have been performed in the frequency range of 50 Hz–5 MHz. The optical absorption experiments of PoPD/MnCuFe{sub 2}O{sub 4} nanocomposites reveal that the direct transition with an energy band gap is around 2 eV. - Highlights: • Green synthesis of PoPD (the polymerization carried out only in aqueous medium) by in-situ chemical polymerization method. • For the first time, PoPD incorporated with MnCuFe{sub 2}O{sub 4} with lesser particle size. • The auto combustion reaction, support to achieve less particle size. • Ferrite content affects the magnetic properties of the nanocomposites.
NMR structure calculation for all small molecule ligands and non-standard residues from the PDB Chemical Component Dictionary

Energy Technology Data Exchange (ETDEWEB)

Yilmaz, Emel Maden; Güntert, Peter, E-mail: guentert@em.uni-frankfurt.de [Goethe University Frankfurt am Main, Center for Biomolecular Magnetic Resonance, Institute of Biophysical Chemistry (Germany)

2015-09-15

An algorithm, CYLIB, is presented for converting molecular topology descriptions from the PDB Chemical Component Dictionary into CYANA residue library entries. The CYANA structure calculation algorithm uses torsion angle molecular dynamics for the efficient computation of three-dimensional structures from NMR-derived restraints. For this, the molecules have to be represented in torsion angle space with rotations around covalent single bonds as the only degrees of freedom. The molecule must be given a tree structure of torsion angles connecting rigid units composed of one or several atoms with fixed relative positions. Setting up CYANA residue library entries therefore involves, besides straightforward format conversion, the non-trivial step of defining a suitable tree structure of torsion angles, and to re-order the atoms in a way that is compatible with this tree structure. This can be done manually for small numbers of ligands but the process is time-consuming and error-prone. An automated method is necessary in order to handle the large number of different potential ligand molecules to be studied in drug design projects. Here, we present an algorithm for this purpose, and show that CYANA structure calculations can be performed with almost all small molecule ligands and non-standard amino acid residues in the PDB Chemical Component Dictionary.
A solution for the preparation of hexagonal M-type SrFe{sub 12}O{sub 19} ferrite using egg-white: Structural and magnetic properties

Energy Technology Data Exchange (ETDEWEB)

Li, Tingting; Li, Yang; Wu, Ruonan; Zhou, Han; Fang, Xiaochen [Anhui Key Laboratory of Metal Materials and Processing, School of Materials Science and Engineering, Anhui University of Technology, Maanshan 243002 (China); Su, Shubing [School of Electronic and Information Engineering, Ningbo University of Technology, Ningbo 315016 (China); Xia, Ailin, E-mail: alxia@126.com [Anhui Key Laboratory of Metal Materials and Processing, School of Materials Science and Engineering, Anhui University of Technology, Maanshan 243002 (China); Jin, Chuangui; Liu, Xianguo [Anhui Key Laboratory of Metal Materials and Processing, School of Materials Science and Engineering, Anhui University of Technology, Maanshan 243002 (China)

2015-11-01

A new sol–gel route using egg-white as the binder of metal ions, is developed to prepare hexagonal M-type SrFe{sub 12}O{sub 19} ferrite in this study, and the effects of different atomic ratio of Sr and Fe (Sr/Fe), sintering temperature (T{sub s}) and usage of egg-white (M{sub ew}) on the phase formation, morphology and magnetic properties of specimens are studied. It is found that the single-phase SrFe{sub 12}O{sub 19} ferrite only can be obtained under a Sr/Fe of 1:8 and a T{sub s} between 1000 °C and 1300 °C. The magnetic properties of specimens are also obviously affected by the different Sr/Fe and T{sub s}, primarily due to the emergency of impurities. The M{sub ew} has an obvious impact on the crystallinity of specimens, which consequently affects their magnetic properties. In our study, the optimum conditions to prepare the single-phase SrFe{sub 12}O{sub 19} ferrite are Sr/Fe=1:8, M{sub ew}= 3 g and T{sub s} =1200 °C. - Highlights: • Single-phase SrM ferrite was obtained via a novel sol–gel method using egg-white. • Single-phase SrM ferrite was obtained under Sr/Fe=1:8 and T{sub s} between 1000 and 1300 °C. • The usage of egg-white affects the crystallinity and magnetic properties markedly.
Effect of calcination temperature on the H{sub 2}O{sub 2} decomposition activity of nano-crystalline Co{sub 3}O{sub 4} prepared by combustion method

Energy Technology Data Exchange (ETDEWEB)

Makhlouf, M.Th. [Chemistry Department, Faculty of Science, Assiut University, 71516 Assiut (Egypt); Abu-Zied, B.M., E-mail: babuzied@aun.edu.eg [Chemistry Department, Faculty of Science, Assiut University, 71516 Assiut (Egypt); Mansoure, T.H. [Chemistry Department, Faculty of Science, Assiut University, 71516 Assiut (Egypt)

2013-06-01

Cobalt oxide nano-particles were prepared by combustion method using urea as a combustion fuel. The effects of calcination temperature, 350–1000 °C, on the physicochemical, surface and catalytic properties of the prepared Co{sub 3}O{sub 4} nano-particles were studied. The products were characterized by thermal analyses (TGA and DTA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques. Textural features of the obtained catalysts were investigated using nitrogen adsorption at −196 °C. X-ray diffraction confirmed that the resulting oxide was pure single-crystalline Co{sub 3}O{sub 4} nano-particles. Transmission electron microscopy indicating that, the crystallite size of Co{sub 3}O{sub 4} nano-crystals was in the range of 8–34 nm. The catalytic activities of prepared nano-crystalline Co{sub 3}O{sub 4} catalysts were tested for H{sub 2}O{sub 2} decomposition at 35–50 °C temperature range. Experimental results revealed that, the catalytic decomposition of H{sub 2}O{sub 2} decreases with increasing the calcination temperature. This was correlated with the observed particle size increase accompanying the calcination temperature rise.
Influence of P{sub 2}O{sub 5} and Al{sub 2}O{sub 3} content on the structure of erbium-doped borosilicate glasses and on their physical, thermal, optical and luminescence properties

Energy Technology Data Exchange (ETDEWEB)

Bourhis, Kevin, E-mail: k.bourhis@argolight.com [Politecnico di Torino, DISAT, Istituto di Ingegneria e Fisica dei Materiali, Corso Duca degli Abruzzi 24, I-10129 Torino (Italy); Massera, Jonathan [Process Chemistry Centre, Åbo Akademi University, Biskopsgatan 8, FI-20500 Turku (Finland); Petit, Laeticia; Ihalainen, Heikki [nLIGHT Corporation, Sorronrinne 9, FI-08500 Lohja (Finland); Fargues, Alexandre; Cardinal, Thierry [CNRS, Université de Bordeaux, ISM, 351Cours de la Libération, F-33405 Talence (France); Hupa, Leena; Hupa, Mikko [Process Chemistry Centre, Åbo Akademi University, Biskopsgatan 8, FI-20500 Turku (Finland); Dussauze, Marc; Rodriguez, Vincent [CNRS, Université de Bordeaux, ICMCB, 87 Avenue du Dr Schweitzer, F-33608 Pessac (France); Boussard-Plédel, Catherine; Bureau, Bruno; Roiland, Claire [Equipe Verres et Céramiques, UMR-CNRS 6226, Inst. des Sciences chimiques de Rennes, Université de Rennes 1, 35042 Rennes CEDEX (France); Ferraris, Monica [Politecnico di Torino, DISAT, Istituto di Ingegneria e Fisica dei Materiali, Corso Duca degli Abruzzi 24, I-10129 Torino (Italy)

2015-03-15

Highlights: • Reorganization of the glass structure induced by the addition of P{sub 2}O{sub 5} or Al{sub 2}O{sub 3}. • Emission properties related to the presence of P or Al in the Er{sup 3+} coordination shell. • Declustering observed upon addition of P{sub 2}O{sub 5}. • No declustering upon addition of Al{sub 2}O{sub 3}. - Abstract: The effect of P{sub 2}O{sub 5} and/or Al{sub 2}O{sub 3} addition in Er-doped borosilicate glasses on the physical, thermal, optical, and luminescence properties is investigated. The changes in these glass properties are related to the glass structure modifications induced by the addition of P{sub 2}O{sub 5} and/or Al{sub 2}O{sub 3}, which were probed by FTIR, {sup 11}B MAS NMR and X-ray photoelectron spectroscopies. Variations of the polymerization degree of the silicate tetrahedra and modifications in the {sup [3]}B/{sup [4]}B ratio are explained by a charge compensation mechanism due to the formation of AlO{sub 4}, PO{sub 4} groups and the formation of Al-O-P linkages in the glass network. From the absorption and luminescence properties of the Er{sup 3+} ions at 980 nm and 1530 nm, declustering is suspected for the highest P{sub 2}O{sub 5} concentrations while for the highest Al{sub 2}O{sub 3} concentrations no declustering is observed.
Human impacts on groundwater flow and contamination deduced by multiple isotopes in Seoul City, South Korea

Energy Technology Data Exchange (ETDEWEB)

Hosono, Takahiro, E-mail: hosono@chikyu.ac.jp [Research Institute for Humanity and Nature, 457-4 Motoyama Kamigamo, Kita-ku, Kyoto 603-8047 (Japan); Ikawa, Reo, E-mail: r_ikawa@es.sci.kumamoto-u.ac.jp [Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555 (Japan); Shimada, Jun, E-mail: jshimada@sci.kumamoto-u.ac.jp [Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555 (Japan); Nakano, Takanori, E-mail: nakanot@chikyu.ac.jp [Research Institute for Humanity and Nature, 457-4 Motoyama Kamigamo, Kita-ku, Kyoto 603-8047 (Japan); Saito, Mitsuyo, E-mail: misaito@hiroshima-u.ac.jp [Graduate School of Biosphere Science, Hiroshima University, 1-7-1, Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8521 (Japan); Onodera, Shin-ichi, E-mail: sonodera@hiroshima-u.ac.jp [Graduate School of Integrated Arts and Sciences, Hiroshima University, 1-7-1, Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8521 (Japan); Lee, Kang-Kun, E-mail: kklee@snu.ac.kr [School of Earth and Environmental Science, Seoul National University, San 56-1, Shinrim-dong, Kwanak-gu, Seoul 151-747 (Korea, Republic of); Taniguchi, Makoto, E-mail: makoto@chikyu.ac.jp [Research Institute for Humanity and Nature, 457-4 Motoyama Kamigamo, Kita-ku, Kyoto 603-8047 (Japan)

2009-04-15

The influence of human activities on the flow system and contamination of groundwater were investigated in Seoul City, South Korea, one of the largest Asian cities, using a combination of isotopes ({delta}D, T, {delta}{sup 15}N, {delta}{sup 18}O, {delta}{sup 34}S, and {sup 87}Sr/{sup 86}Sr). Eighteen representative groundwater and river water samples, which were collected over a wide area of the city, were compared with previously reported data. The distribution of stable isotopes ({delta}D and {delta}{sup 18}O) with groundwater potential data shows that recharged groundwater from either the surrounding mountainous area as well as the Han River and other surface streams discharged towards the northern-central part of the city, where a subway tunnel pumping station is located. It is suggested from T values (3.3 to 5.8 T.U.) that groundwater was recharged in the last 30 to 40 years. The {delta}{sup 34}S and {delta}{sup 15}N of SO{sub 4}{sup 2-} and NO{sub 3}{sup -} data were efficiently used as indicators of contamination by human activities. These isotopes clarified that the contribution of anthropogenic contaminants i.e., industrial and household effluents, waste landfills, and fertilizers, are responsible for the enrichment by SO{sub 4}{sup 2-} (> 30 ppm as SO{sub 4}{sup 2-}) and NO{sub 3}{sup -} (> 20 ppm as NO{sub 3}{sup -}) of groundwater. The {sup 87}Sr/{sup 86}Sr values of groundwater vary (0.71326 to 0.75058) in accordance with the host rocks of different origins. Mineral elements such as Ca are also suggested to be derived naturally from rocks. The groundwater under Seoul City is greatly affected by transportation of pollutants along the groundwater flow controlled by subway tunnel pumping, contributing to the degradation of water quality in urbanized areas.
Electrochemical sensing behaviour of Ni doped Fe{sub 3}O{sub 4} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Suresh, R.; Giribabu, K.; Manigandan, R.; Narayanan, V., E-mail: vnnara@yahoo.co.in [Department of Inorganic Chemistry, University of Madras, Guindy Campus, Chennai 600 025 (India); Vijayalakshmi, L. [Annai Veilankanni' s College for Women (Arts and Science), Saidapet, Chennai 600015 (India); Stephen, A. [Department of Nuclear Physics, University of Madras, Guindy Campus, Chennai 600 025 (India)

2014-01-28

Ni doped Fe{sub 3}O{sub 4} nanoparticles were synthesized by simple hydrothermal method. The prepared nanomaterials were characterized by X-ray diffraction analysis, DRS-UV-Visible spectroscopy and field emission scanning electron microscopy. The XRD confirms the phase purity of the synthesized Ni doped Fe{sub 3}O{sub 4} nanoparticles. The optical property of Ni doped Fe{sub 3}O{sub 4} nanoparticles were studied by DRS UV-Visible analysis. The electrochemical sensing property of pure and Ni doped Fe{sub 3}O{sub 4} nanoparticles were examined using uric acid as an analyte. The obtained results indicated that the Ni doped Fe{sub 3}O{sub 4} nanoparticles exhibited higher electrocatalytic activity towards uric acid.
Crystal growth and structure of KLnP/sub 4/O/sub 12/

International Nuclear Information System (INIS)

Guangyan, H.; Shuzhen, L.; Shuying, Y.; Mingyu, C.

1985-01-01

Potassium rare earth tetraphosphates KLnP/sub 4/O/sub 12/ are a kind of polyphosphates of rare earths with unique properties and structures. KNdP/sub 4/O/sub 12/ is a high-Nd-concentration laser material with a non-centrosymmetric space group P2, yielding linear and nonlinear optical properties. α-KErP/sub 4/O/sub 12/ might be used as a material for engineering device purpose. KTbP/sub 4/O/sub 12/ can emit strong green fluorescence, it might be a kind of a new crystal material for laser or luminescence. In order to search for new crystal materials and to study the correlations among the composition, structures and the properties of rare earth compounds, the crystal growth of KLnP/sub 4/O/sub 12/ and their structures are studied in this paper
Synthesis of Y{sub 1-x}Al{sub x}Ba{sub 2}Cu{sub 3}O{sub 7-δ} via combustion route: Effects of Al{sub 2}O{sub 3} nanoparticles on superconducting properties

Energy Technology Data Exchange (ETDEWEB)

Mohd Suan, Mohd Shahadan, E-mail: mohdshahadan@utem.edu.my [Department of Engineering Materials, Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka, 76100 Durian Tunggal, Melaka (Malaysia); Johan, Mohd Rafie [Nanomaterial Engineering Research Group, Advanced Materials Research Laboratory, Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2017-02-01

Combustion reaction was used to synthesis Al{sub 2}O{sub 3} nanoparticles embedded Y{sub 1-x}Al{sub x}Ba{sub 2}Cu{sub 3}O{sub 7-δ} simultaneously. The effects of Al{sub 2}O{sub 3} nanoparticles with nominal molar mass (x{sub mol}) of 0.02, 0.04, 0.06, 0.08 and 0.10 towards the critical current density J{sub C} of Y{sub 1-x}Al{sub x}Ba{sub 2}Cu{sub 3}O{sub 7-δ} were verified by magnetic measurement. Resulted XRD patterns revealed that the calcined samples consist of pure Al{sub 2}O{sub 3} and Y{sub 1-x}Al{sub x}Ba{sub 2}Cu{sub 3}O{sub 7-δ} phases which had been confirmed by EDX results. The SEM images showed that Al{sub 2}O{sub 3} nanoparticles (~10 nm) were distributed in polycrystalline YBa{sub 2}Cu{sub 3}O{sub 7-δ} grains and grain boundaries. The presence of higher concentration of Al{sub 2}O{sub 3} nanoparticles has developed Al{sup 3+} rich spots which diffused within the YBa{sub 2}Cu{sub 3}O{sub 7-δ} superconducting matrix to form Y{sub 1-x}Al{sub x}Ba{sub 2}Cu{sub 3}O{sub 7-δ} and was confirmed by EDX analysis. The samples were electrically superconducting at temperature above 85 K as measured by using standard four-probe technique. The magnetic field (H) dependent magnetization (M), M-H hysteresis loops measured at 77 K for x{sub mol}≤0.06 samples are significantly improved attributed to the increase of trapped fluxes in the samples. Remarkable increase of magnetic J{sub C} (H) in Al{sub 2}O{sub 3} nanoparticles added samples compared to the as prepared polycrystalline YBa{sub 2}Cu{sub 3}O{sub 7-δ} sample indicating strong pinning effect. It is suggested that well-distributed Al{sub 2}O{sub 3} nanoparticles in the polycrystalline YBa{sub 2}Cu{sub 3}O{sub 7-δ} matrix achieved via auto-combustion reaction has efficiently pin the magnetic vortex. The magnetic J{sub C} was optimized to ~6 kAcm{sup -2} in x{sub mol}=0.06 sample. On the other hand, insignificant magnetic J{sub C} improvement in x{sub mol}≥0.08 samples is probably resulted from the
Structure of Na/sub 2/AlBAs/sub 4/O/sub 14/, a condensed aluminoboroarsenate

Energy Technology Data Exchange (ETDEWEB)

Driss, A.; Jouini, T.

1988-05-15

M/sub r/=607.45, monoclinic, P2/sub 1//c, a=4.5916(5), b=20.706(3), c=10.933(1) A, ..beta..=90.39(1)/sup 0/, V=1039.4 A/sup 3/, Z=4, D/sub x/=3.88, D/sub m/ (in bromobenzene)=3.93 Mg m/sup -3/, MoK anti ..cap alpha.., lambda=0.7107 A, ..mu..=13.7 mm/sup -1/, F(000)=1136, T=293 K, R=0.035, ..omega..R=0.047 for 1029 independent reflections. The main feature of this structure is the existence of a novel aluminoboroarsenate anion (Al/sub 2/B/sub 2/As/sub 8/O/sub 28/)/sup 4n-//sub n/ built up from centrosymmetrical B/sub 2/As/sub 4/O/sub 18/ rings formed by corner-sharing of AsO/sub 4/ and BO/sub 4/ tetrahedra and having two As/sub 2/O/sub 7/ pyroarsenate branches. The rings form infinite chains parallel to the a direction by As-O-B linkages. The chains are linked by sharing edges of AsO/sub 4/ tetrahedra and AlO/sub 6/ octahedra to form an infinite three-dimensional framework containing tunnels parallel to the chains where the Na/sup +/ cations are located. This structure is the first ternary heteropolyanion including B, Al and As atoms.
Response of C3 and C4 plants to middle-Holocene climatic variation near the prairie-forest ecotone of Minnesota, U.S.A.

Energy Technology Data Exchange (ETDEWEB)

Tian, J; Brown, T A; Hu, F S; Stefanova, I; Nelson, D M

2003-12-24

Paleorecords of the middle Holocene (MH) from the North American midcontinent can offer insights into ecological responses to pervasive drought that may accompany future climatic warming. We analyzed MH sediments from West Olaf Lake (WOL) and Steel Lake (SL) in Minnesota to examine the effects of warm/dry climatic conditions on prairie-woodland ecosystems. Mineral composition and carbonate {delta}{sup 18}O were used to determine climatic variations, whereas pollen assemblages, charcoal {delta}{sup 13}C, and charcoal accumulation rates were used to reconstruct vegetation composition, C{sub 3} and C{sub 4} plant abundance, and fire. The ratio of aragonite:calcite at WOL and {delta}{sup 18}O at SL suggest that pronounced droughts occurred during the MH but that drought severity decreased with time. From charcoal {delta}{sup 13}C data we estimated that the MH abundance of C{sub 4} plants averaged 50% at WOL and 43% at SL. At WOL C{sub 4} abundance was negatively correlated with aragonite:calcite, suggesting that severe moisture deficits suppressed C{sub 4} plants in favor of weedy C{sub 3} plants (e.g., Ambrosia). As climate ameliorated C{sub 4} abundance increased (from {approx}33 to 66%) at the expense of weedy species, enhancing fuel availability and fire occurrence. In contrast, farther east at SL climate was cooler and wetter than at WOL, and C{sub 4} abundance showed no correlation with {delta}{sup 18}O-inferred aridity. Woody C{sub 3} plants (e.g., Quercus) were more abundant, biomass flammability lower, and fires less important at SL than at WOL. Our results suggest that C{sub 4} plants are adapted to warm/dry climatic conditions, but not to extreme droughts, and that the fire regime is controlled by biomass-climate interactions.
The selectivity of catalysts composed of V/sub 2/O/sub 5/ supported on ZrO/sub 2/-Y/sub 2/O/sub 3/ mixed oxides for methanol oxidation

International Nuclear Information System (INIS)

VanOmmen, J.G.; Gellings, P.J.; Ross, J.R.H.

1988-01-01

V/sub 2/O/sub 5/ monolayer catalysts were prepared on ZrO/sub 2/ and ZrO/sub 2/ doped with Y/sub 2/O/sub 3/ by two methods. The coverages obtained are only half a monolayer and did not depend on the preparation method or type of support. The selectivity for oxidation of methanol over these V/sub 2/O/sub 5/ catalysts changes from a predominance of formaldehyde to a predominance of methyl formate when the support is doped with Y/sub 2/C/sub 3/, independent of the amount of Y/sub 2/O/sub 3/
Architecture of 3D ZnCo{sub 2}O{sub 4} marigold flowers: Influence of annealing on cold emission and photocatalytic behavior

Energy Technology Data Exchange (ETDEWEB)

Kokane, Sanjay B.; Suryawanshi, Sachin R. [Center for Advanced Studies in Material Science and Condensed Matter Physics, Department of Physics, Savitribai Phule Pune University, Pune 411007 (India); Sasikala, R., E-mail: sasikala@barc.gov.in [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 411085 (India); More, Mahendra A., E-mail: mam@physics.unipune.ac.in [Center for Advanced Studies in Material Science and Condensed Matter Physics, Department of Physics, Savitribai Phule Pune University, Pune 411007 (India); Sartale, Shrikrishna D., E-mail: sdsartale@physics.unipune.ac.in [Center for Advanced Studies in Material Science and Condensed Matter Physics, Department of Physics, Savitribai Phule Pune University, Pune 411007 (India)

2017-06-15

The present work demonstrates the field emission characteristics and photocatalytic behavior of ZnCo{sub 2}O{sub 4} marigold flowers synthesized via a facile hydrothermal method. The effect of annealing of these 3D porous hierarchical nanostructures on field emission and photocatalytic performances is studied. When compared with the as-synthesized sample, annealed ZnCo{sub 2}O{sub 4} exhibits a ∼2-fold improvement in photocatalytic activity for methylene blue (MB) degradation under visible light irradiation. The turn-on, threshold fields and high emission current densities are also strongly influenced as a result of annealing. The turn on field required to draw an emission current density of ∼1 μA/cm{sup 2} is found to be ∼2.4 and ∼1.8 V/μm for as-synthesized and annealed ZnCo{sub 2}O{sub 4} marigold flowers, respectively. Field-emission measurements demonstrate remarkably large field enhancement and better stability for annealed samples. The X-ray diffraction and Raman analysis reveal that annealing improves the crystallinity and also help to remove the structural defects in ZnCo{sub 2}O{sub 4}. The enhancement in the field emission and photocatalytic activity of annealed ZnCo{sub 2}O{sub 4} marigold flowers is attributed to the modification of electronic properties as a result of dehydration, crystallite growth and reduced surface defects/impurity phases. - Highlights: • 3D hierarchical porous ZnCo{sub 2}O{sub 4} marigold flowers synthesis by hydrothermal method. • Roles of CTAB as capping agent and thermal annealing are investigated. • Thermal annealing improves photocatalysis and field emission behavior drastically.
Spectroscopy of peaks at microwave range for nanostructure SrFe{sub 12}O{sub 19} and NiFe{sub 2}O{sub 4} ferrite particles

Energy Technology Data Exchange (ETDEWEB)

Ariaee, Sina, E-mail: sina.ariaee@tabrizu.ac.ir; Mehdipour, Mostafa, E-mail: Mostafa_mehdipour67@yahoo.com; Moradnia, Mina, E-mail: mina.moradnia86@gmail.com

2017-05-01

In this paper, (SrFe{sub 12}O{sub 19} and NiFe{sub 2}O{sub 4}) nanostructure ferrite particles were synthesized via the co-precipitation of chloride salts utilizing the sodium hydroxide solution. The resulting precursors were heat-treated at 1100 °C for 4 h. After cooling in the furnace, the ferrite powders were pressed at 0.1 MPa and then sintered at 1200 °C for 4 h. The spectroscopy and characterization of peaks at the microwave range (X-band) for the nanostructure ferrite particles were investigated by the ferromagnetic resonance/transmit-line theories and Reflection Loss (RL) plots. The extracted data from these theoretical and experimental results showed that the natural ferromagnetic resonance can be lead to the narrow peaks and the width of the peaks can be related to the periodic effects. Two kinds of peaks were seen for NiFe{sub 2}O{sub 4} at X-band (8–12 GHz); the narrow peak at (9.8 GHz) was remaining unchanged and consistent while the wide one was shifted from 11 GHz to 8.5 GHz by decreasing the thickness of the samples. These phenomena were also happened for SrFe{sub 12}O{sub 19} samples. The natural resonance was not happened due to the hard magnetic properties of these nano structure particles. - Highlights: • SrFe{sub 12}O{sub 19} and NiFe{sub 2}O{sub 4} nanostructure ferrite particles were synthesized via the co-precipitation of chloride salts. • Two kinds of peaks were seen for NiFe{sub 2}O{sub 4} at X-band (8–12 GHz); these phenomena were also happened for SrFe{sub 12}O{sub 19} samples. • The narrow peaks were remained unchanged and consistent while the wide ones were shifted by decreasing the thickness of the samples. • Characterization procedure was conducted utilizing the ferromagnetic resonance/transmit-line theories and Reflection Loss (RL) plots. • It was concluded that the natural ferromagnetic resonance can be lead to the narrow peaks while the wide ones can be related to the periodic effects.
Hydrogeochemical and Isotopic Characteristics of Tufa Precipitating Wates: A Case Study of the River Krka (Slovenia)

Energy Technology Data Exchange (ETDEWEB)

Zavadlav, S.; Lojen, S. [Jozef Stefan Institute, Department of Environmental Sciences, Ljubljana (Slovenia)

2013-07-15

The geochemical and stable isotope composition of tufa precipitating water in the River Krka in the Slovenian karst area were studied. Surface water chemistry in the River Krka is controlled by groundwater interactions with carbonate rocks, soil CO{sub 2} and meteoric water in the aquifer. Major element chemistry of water is controlled by dissolution of dolomite and calcite. The aquifer is the main source of cations, since concentrations of Mg{sup 2+}, Sr{sup 2+} and Ba{sup 2+} in water are highest at the spring. Ca{sup 2+} concentrations are slightly increasing due to the additional mixing of surface and groundwater downstream. Oxygen isotope composition of water indicates homogenization of meteoric water in the aquifer, while {delta}{sup 13}C values of dissolved inorganic carbon in water are affected by biological activity in the soil. {delta}{sup 18}O and {delta}{sup 13}C of bulk tufa show that deposition of tufa precipitates in the River Krka is kinetically controlled resulting in enrichment with heavier isotopes. Calculated equilibrium temperature of tufa precipitation based on the oxygen isotope composition of water and tufa fit with measured water temperature when average {delta}{sup 18}O values of water and tufa are considered. (author)
Isotopic Composition and Age of Surface Water as Indicators of Groundwater Sustainability in a Semiarid Area: Case of the Souss Basin (Morocco)

Energy Technology Data Exchange (ETDEWEB)

Bouchaou, L.; Tagma, T.; Boutaleb, S.; Hsissou, Y. [LAGAGE Laboratory, Ibn Zohr University, Agadir (Morocco); Nathaniel, W.; Vengosh, A. [Duke University (United States); Michelot, J. L.; Massault, M. [UMR ' IDES' , CNRS - Universite Paris-Sud, Orsay (France); Elfaskaoui, M. [Hydraulic Agency of Souss-Massa-Draa Basins, Agadir (Morocco)

2013-07-15

This study aims to determine the surface water and groundwater interconnection in the Souss catchment of western Morocco by applying multiple isotopic tracers such as {delta}{sup 18}O, {delta}{sup 2}H, {sup 3}H, Ra, {sup 14}C, {sup 87}Sr/{sup 86}Sr and CFCs. Stable water isotope data indicate that the High Atlas Mountains, with their high rainfall and low {delta}{sup 18}O and {delta}{sup 2}H values, constitute the major source of recharge to the Souss-Massa aquifer. Carbon-{sup 14} activities (34-94 pMC) and {sup 3}H indicate a long residence time of groundwater in some areas. The high {sup 14}C activities measured in the Ifni spring located at 2158 m a.s.l. and the Tiar spring at 711 m a.s.l. indicate a modern contribution, which is consistent with recharge from the High Atlas tributaries. In the upstream mountainous section, the mass balance mixing model suggest that groundwater contribution to stream flow is about 72% during the wet season and 36% during the dry season. In the downstream plain, 80% of surface flow infiltrates to the aquifer. {sup 226}Ra and {sup 87}Sr/{sup 86}Sr variations were indistinguishable for surface waters and groundwater. (author)

Oxide (CeO{sub 2}, NiO, Co{sub 3}O{sub 4} and Mn{sub 3}O{sub 4})-promoted Pd/C electrocatalysts for alcohol electrooxidation in alkaline media

Energy Technology Data Exchange (ETDEWEB)

Xu, Changwei; Tian, Zhiqun; Jiang, San Ping [School of Mechanical and Aerospace Engineering, Nanyang Technological University (Singapore); Shen, Peikang [School of Physics and Engineering, Sun Yat-Sen University, Guangzhou 510275 (China)

2008-01-01

This study investigated Pt/C, Pd/C and oxide (CeO{sub 2}, NiO, Co{sub 3}O{sub 4} and Mn{sub 3}O{sub 4})-promoted Pd/C for electrooxidation reactions of methanol, ethanol, ethylene glycol and glycerol in alkaline media. The results show that Pd/C electrocatalysts alone have low activity and very poor stability for the alcohol electrooxidation. However, addition of oxides like CeO{sub 2}, NiO, Co{sub 3}O{sub 4} and Mn{sub 3}O{sub 4} significantly promotes catalytic activity and stability of the Pd/C electrocatalysts for the alcohol electrooxidation. The Pd-Co{sub 3}O{sub 4} (2:1, w:w)/C shows the highest activity for the electrooxidation of methanol, EG and glycerol while the most active catalyst for the ethanol electrooxidation is Pd-NiO (6:1, w:w)/C. On the other hand, Pd-Mn{sub 3}O{sub 4}/C shows significantly better performance stability than other oxide-promoted Pd/C for the alcohol electrooxidation. The poor stability of the Pd-Co{sub 3}O{sub 4}/C electrocatalysts is most likely related to the limited solubility of cobalt oxides in alkaline solutions. (author)
Oxidative and antibacterial activity of Mn{sub 3}O{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Chowdhury, Al-Nakib, E-mail: nakib@chem.buet.ac.bd [Department of Chemistry, Bangladesh University of Engineering and Technology, Dhaka-1000 (Bangladesh); Azam, Md. Shafiul, E-mail: azam@ualberta.ca [Department of Chemistry, Bangladesh University of Engineering and Technology, Dhaka-1000 (Bangladesh); Aktaruzzaman, Md.; Rahim, Abdur [Department of Chemistry, Bangladesh University of Engineering and Technology, Dhaka-1000 (Bangladesh)

2009-12-30

Mn{sub 3}O{sub 4} nanoparticles with diameter ca. 10 nm were synthesized by the forced hydrolysis of Mn(II) acetate at 80 deg. C. The X-ray diffraction (XRD), Fourier transform infra red (FT-IR) spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) techniques were employed to study structural features and chemical composition of the nanoparticles. The unique oxidative activity of the Mn{sub 3}O{sub 4} nanoparticles was demonstrated in the polymerization and dye degradation reactions. On adding Mn{sub 3}O{sub 4} suspension to an acidic solution of aniline, yielded immediately green sediment of polyaniline (PANI). The organic dyes, viz., methylene blue (MB) and procion red (PR) were found to be completely decolorized from their aqueous solution on treating the dyes with Mn{sub 3}O{sub 4} suspension in acidic media. The Mn{sub 3}O{sub 4} nanoparticles also showed a clear antibacterial activity against the Vibrio cholerae, Shigella sp., Salmonella sp., and Escherichi coli bacteria that cause cholera, dysentery, typhoid, and diarrhea diseases, respectively.
Microwave-enhanced electrochemical cycling performance of the LiNi0.2Mn1.8O4 spinel cathode material at elevated temperature

CSIR Research Space (South Africa)

Raju, Kumar

2016-04-01

Full Text Available microwave-assisted solid-state reaction has been used to dope LMO with a very low amount of nickel (i.e., LiNi(sub0.2)Mn(sub1.8)O(sub4), herein abbreviated as LMNO) for lithium-ion batteries from Mn(sub3)O(sub4) which is prepared from electrolytic manganese...
Pb solubility of the high-temperature superconducting phase Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10+d}

Energy Technology Data Exchange (ETDEWEB)

Kaesche, S.; Majewski, P.; Aldinger, F. [Max-Planck-Institut fuer Metallforschung, Stuttgart (Germany)] [and others

1994-12-31

For the nominal composition of Bi{sub 2.27x}Pb{sub x}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10+d} the lead content was varied from x=0.05 to 0.45. The compositions were examined between 830{degrees}C and 890{degrees}C which is supposed to be the temperature range over which the so-called 2223 phase (Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10+d}) is stable. Only compositions between x=0.18 to 0.36 could be synthesized in a single phase state. For x>0.36 a lead containing phase with a stoichiometry of Pb{sub 4}(Sr,Ca){sub 5}CuO{sub d} is formed, for x<0.18 mainly Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+d} and cuprates are the equilibrium phases. The temperature range for the 2223 phase was found to be 830{degrees}C to 890{degrees}C but the 2223 phase has extremely varying cation ratios over this temperature range. Former single phase 2223 samples turn to multi phase samples when annealed at slightly higher or lower temperatures. A decrease in the Pb solubility with increasing temperature was found for the 2223 phase.
Current-voltage characteristics of SnO{sub 2}-Co{sub 3}O{sub 4}-Cr{sub 2}O{sub 3}-Sb{sub 2}O{sub 5} ceramics

Energy Technology Data Exchange (ETDEWEB)

Aguilar-Martinez, J A [Centro de Investigacion en Materiales Avanzados, S.C. (CIMAV), Alianza Norte 202, Parque de Investigacion e Innovacion Tecnologica (PIIT), Nueva Carretera Aeropuerto km. 10, Apodaca, Nuevo Leon, CP 66600 (Mexico); Glot, A B [Posgrado, Universidad Tecnologica de la Mixteca, Carretera Acatlima Km. 2.5, Huajuapan de Leon, Oaxaca, CP 69000 (Mexico); Gaponov, A V [Department of Radioelectronics, Dniepropetrovsk National University, Dniepropetrovsk 49050 (Ukraine); Hernandez, M B [Instituto de Mineria, Universidad Tecnologica de la Mixteca, Carretera Acatlima Km. 2.5, Huajuapan de Leon, Oaxaca, CP 69000 (Mexico); Guerrero-Paz, J, E-mail: josue.aguilar@cimav.edu.m [Particulate Materials Lab, Universidad Autonoma del Estado de Hidalgo, Pachuca, CP 42184 (Mexico)

2009-10-21

The effect of mechanical treatment in a planetary mill on the microstructure and electrical properties of tin dioxide based varistor ceramics in the system SnO{sub 2}-Co{sub 3}O{sub 4}-Cr{sub 2}O{sub 3}-Sb{sub 2}O{sub 5} sintered in the range 1150-1450 {sup 0}C was studied. The mechanical treatment leads to an increase in shrinkage, decrease in porosity, decrease in sample diameter, change in colour of the sintered samples from grey to black and enhancement of nonlinearity. For the sample sintered at 1350 {sup 0}C the mechanical treatment enhances the nonlinearity coefficient from 11 to 31 and decreases the electric field E{sub 1} (at 10{sup -3} A cm{sup -2}) from 3500 to 2800 V cm{sup -1}. The observed changes in physical properties are explained in terms of an additional size reduction of oxide particles and a better mixing of oxide powder followed by the formation of potential barriers at the grain boundaries throughout the whole sample. In spite of the low porosity, the low-field electrical conductivity of mechanically treated ceramics is significantly increased with the growth of relative humidity. A higher humidity sensitivity is found for mechanically treated ceramics with higher barrier height and higher nonlinearity coefficient.
RE{sub 2}B{sub 8}O{sub 15} (RE = La, Pr, Nd). Syntheses of three new rare earth borates isotypic to Ce{sub 2}B{sub 8}O{sub 15}

Energy Technology Data Exchange (ETDEWEB)

Glaetzle, Matthias; Hoerder, Gregor J.; Huppertz, Hubert [Innsbruck Univ. (Austria). Inst. fuer Allgemeine, Anorganische und Theoretische Chemie

2016-08-01

The rare earth borates RE{sub 2}B{sub 8}O{sub 15} (RE = La, Pr, Nd) were synthesized in a Walker-type multianvil apparatus under conditions of 5.5 GPa and 1100 C. Starting from the corresponding rare earth oxides and boron oxide, the syntheses yielded crystalline products of all new compounds that allowed crystal structure analyses based on single-crystal X-ray diffraction data for La{sub 2}B{sub 8}O{sub 15} and Nd{sub 2}B{sub 8}O{sub 15}. The compound Pr{sub 2}B{sub 8}O{sub 15} could be characterized via X-ray powder diffractometry. The results show that the new compounds crystallize isotypically to Ce{sub 2}B{sub 8}O{sub 15} in the monoclinic space group P2/c. The infrared spectra of RE{sub 2}B{sub 8}O{sub 15} (RE = La, Pr, Nd) have also been studied.
Kinetics of dissolution of {alpha}-Fe{sub 2}O{sub 3} and {gamma}-Fe{sub 2}O{sub 3} in EDTA and NTA-based formulations

Energy Technology Data Exchange (ETDEWEB)

Ranganathan, S. [Dept. of Chemical Engineering, Univ. of New Brunswick, Fredericton, N.B. (Canada); Srinivasan, M.P. [Water and Steam Chemistry Lab. of Bhabha Atomic Research Centre (BARC) (India); Narasimhan, S.V. [Bhabha Atomic Research Centre (India); Raghavan, P.S. [Madras Christian Coll., Chennai (India); Gopalan, R. [Dept. of Chemistry, Madras Christian Coll., Chennai (India)

2004-06-01

The dissolution studies were carried out on haematite ({alpha}-Fe{sub 2}O{sub 3}) and maghemite ({gamma}-Fe{sub 2}O{sub 3}) in two different formulations of ethylenediaminetetraacetic acid (EDTA) and nitrilotriaceticacid (NTA). The rate constants were calculated using the ''inverse cubic rate law.'' The leaching of the metal ions from the oxide is controlled partly by the Fe(II)-L{sub n} (L is a complexing ligand and n is the number of ligands attached to Fe{sup 2+}), a dissolution product arising from the oxides having Fe{sup 2+} in the lattice. The addition of Fe(II)-L{sub n} along with the formulation greatly increased the initial rate of dissolution. The effect of the addition of Fe(II)-L as a reductant on the dissolution of {alpha}-Fe{sub 2}O{sub 3} was not the same as in the case of {gamma}-Fe{sub 2}O{sub 3}. The rate constants (k{sub obs}) for the dissolution of {alpha}-Fe{sub 2}O{sub 3} and {gamma}-Fe{sub 2}O{sub 3} in the presence of ascorbic acid were less in the EDTA formulation than in the NTA formulation. The studies using Fe(II)-NTA and Fe(II)-EDTA with varying compositions of citric acid and ascorbic acid revealed that a minimum quantity of the chelant is sufficient to initiate the dissolution process, which can be further controlled by the reductants and weaker chelants such as citric acid. (orig.)
Correlation between microstructure and electrical properties of Cu{sub 1.3}Mn{sub 1.7}O{sub 4}/La{sub 2}O{sub 3} composite-coated ferritic stainless steel interconnects

Energy Technology Data Exchange (ETDEWEB)

Hosseini, N., E-mail: nazaneen_hosseini@ma.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Karimzadeh, F.; Abbasi, M.H. [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Choi, G.M. [Fuel Cell Research Center and Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of)

2016-07-15

The goal of this study was to investigate the effect of screen-printed Cu{sub 1.3}Mn{sub 1.7}O{sub 4}/La{sub 2}O{sub 3} composite coating on chromia scale growth and electrical behavior of AISI430 stainless steel interconnects. The coated samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy equipped with energy dispersive spectroscopy (FESEM-EDS) and 4-probe area specific resistance (ASR) tests. The results showed that LaCrO{sub 3} conductive perovskite is formed due to the interdiffusion between Cr{sub 2}O{sub 3} and/or CrO{sub 3} and La{sub 2}O{sub 3}. The presence of LaCrO{sub 3} through the composite coating and Cr{sub 2}O{sub 3} sub-scale accompanied by the effective role of spinel phase, acted as a barrier to mitigate the sub-scale growth preventing chromium diffusion through the coating and the cathode. Besides, LaCrO{sub 3} particles within the sub-scale provided suitable conductive paths decreasing ASR from 19.3 mΩ cm{sup 2} for spinel coated sample to 15 mΩ cm{sup 2} for composite coated sample at the end of 500 h oxidation at 750° C. - Highlights: • Cu{sub 1.3}Mn{sub 1.7}O{sub 4}/La{sub 2}O{sub 3} coating was deposited on AISI 430 by screen-printing method. • LaCrO{sub 3} perovskite was formed due to the interdiffusion between Cr species and La{sub 2}O{sub 3}. • LaCrO{sub 3} particles within the chromia provided conductive paths causing ASR reduction. • The co-existence of LaCrO{sub 3} and Cu{sub 1.3}Mn{sub 1.7}O{sub 4} noticeably retarded the chromia growth.
Electronic structure and vibrational properties of KRbAl{sub 2}B{sub 2}O{sub 7}

Energy Technology Data Exchange (ETDEWEB)

Atuchin, V.V. [Laboratory of Optical Materials and Structures, Institute of Semiconductor Physics, SB RAS, Novosibirsk 90, 630090 (Russian Federation); Adichtchev, S.V. [Laboratory of Condensed Matter Spectroscopy, Institute of Automation and Electrometry, SB RAS, Novosibirsk 90, 630090 (Russian Federation); Bazarov, B.G.; Bazarova, Zh.G. [Laboratory of Oxide Systems, Baikal Institute of Nature Management, SB RAS, Ulan-Ude 47, 670047 (Russian Federation); Gavrilova, T.A. [Laboratory of Nanodiagnostics and Nanolithography, Institute of Semiconductor Physics, SB RAS, Novosibirsk 630090 (Russian Federation); Grossman, V.G. [Laboratory of Oxide Systems, Baikal Institute of Nature Management, SB RAS, Ulan-Ude 47, 670047 (Russian Federation); Kesler, V.G. [Laboratory of Physical Principles for Integrated Microelectronics, Institute of Semiconductor Physics, Novosibirsk, 630090 (Russian Federation); Meng, G.S. [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, P.O. Box 2711, Beijing 100190 (China); Key Laboratory of Quantum Information, University of Science and Technology of China, Chinese Academy of Sciences, Hefei, Anhui 230026 (China); Lin, Z.S., E-mail: zslin@mail.ipc.ac.cn [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, P.O. Box 2711, Beijing 100190 (China); Surovtsev, N.V. [Laboratory of Condensed Matter Spectroscopy, Institute of Automation and Electrometry, SB RAS, Novosibirsk 90, 630090 (Russian Federation)

2013-03-15

Graphical abstract: With the KRbAl{sub 2}B{sub 2}O{sub 7} powder formed by solid state synthesis (left), Raman spectrum (right upper) and XPS valence electronic states (right lower) were measured, agreed with the first-principles results. Highlights: ► KRbAl{sub 2}B{sub 2}O{sub 7} powder was obtained by solid state synthesis. ► Vibrational properties of KRbAl{sub 2}B{sub 2}O{sub 7} were determined by unpolarized Raman spectrum. ► Electronic structures of KRbAl{sub 2}B{sub 2}O{sub 7} were measured by XPS. ► Experimental electronic structure is consistent with the first-principles result. ► KRbAl{sub 2}B{sub 2}O{sub 7} has a noticeable refractive indices increase and small NLO effects decrease compared to K{sub 2}Al{sub 2}B{sub 2}O{sub 7}. - Abstract: The physical properties of KRbAl{sub 2}B{sub 2}O{sub 7} have been considered in comparison with those of K{sub 2}Al{sub 2}B{sub 2}O{sub 7} and Rb{sub 2}Al{sub 2}B{sub 2}O{sub 7}. The vibrational parameters of KRbAl{sub 2}B{sub 2}O{sub 7} have been measured by Raman spectroscopy as very similar to those of K{sub 2}Al{sub 2}B{sub 2}O{sub 7}. The electronic structures of KRbAl{sub 2}B{sub 2}O{sub 7} have been evaluated by X-ray photoelectron spectroscopy and ab initio computations using CASTEP package. A noticeable refractive indices increase and small decrease of nonlinear optical properties have been found in KRbAl{sub 2}B{sub 2}O{sub 7} in reference to optical parameters of K{sub 2}Al{sub 2}B{sub 2}O{sub 7}.
Fabrication, characterization, and photocatalytic property of {alpha}-Fe{sub 2}O{sub 3}/graphene oxide composite

Energy Technology Data Exchange (ETDEWEB)

Li Hong; Zhao Qidong; Li Xinyong, E-mail: xinyongli@hotmail.com [School of Environmental Science and Technology, Dalian University of Technology, State Key Laboratory of Fine Chemical, Key Laboratory of Industrial Ecology and Environmental Engineering (MOE) (China); Zhu Zhengru [Research Center of Hydrology and Engineering, Academy of City and Environment, Liaoning Normal University (China); Tade, Moses; Liu Shaomin, E-mail: shaomin.liu@curtin.edu.au [Curtin University, Department of Chemical Engineering (Australia)

2013-06-15

Spindle-shaped microstructure of {alpha}-Fe{sub 2}O{sub 3} was successfully synthesized by a simple hydrothermal method. The {alpha}-Fe{sub 2}O{sub 3}/graphene oxide (GO) composites was prepared using a modified Hummers' strategy. The properties of the samples were systematically investigated by X-ray powder diffraction (XRD), UV-Vis diffuse reflectance spectrophotometer, transmission electron microscope, atomic force microscope, X-ray photoelectron spectroscopy, and Raman spectroscopy (Raman) techniques. GO nanosheets act as supporting materials for anchoring the {alpha}-Fe{sub 2}O{sub 3} particles. The average crystallite sizes of the {alpha}-Fe{sub 2}O{sub 3} and {alpha}-Fe{sub 2}O{sub 3}/GO samples are ca. 27 and 24 nm, respectively. The possible growth of {alpha}-Fe{sub 2}O{sub 3} onto GO layers led to a higher absorbance capacity for visible light by {alpha}-Fe{sub 2}O{sub 3}/GO than {alpha}-Fe{sub 2}O{sub 3} composite. The photocatalytic degradation of toluene over the {alpha}-Fe{sub 2}O{sub 3} and {alpha}-Fe{sub 2}O{sub 3}/GO samples under xenon-lamp irradiation was comparatively studied by in situ FTIR technique. The results indicate that the {alpha}-Fe{sub 2}O{sub 3}/GO sample synthesized exhibited a higher capacity for the degradation of toluene. The composite of {alpha}-Fe{sub 2}O{sub 3}/GO could be promisingly applied in photo-driven air purification.
Electric-field gradients at {sup 181}Ta impurity sites in Ho{sub 2}O{sub 3} and Eu{sub 2}O{sub 3} bixbyites

Energy Technology Data Exchange (ETDEWEB)

Errico, Leonardo A. [Departamento de Fisica-IFLP(CONICET), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, C.C. 67, 1900 La Plata (Argentina); Renteria, Mario [Departamento de Fisica-IFLP(CONICET), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, C.C. 67, 1900 La Plata (Argentina)]. E-mail: renteria@fisica.unlp.edu.ar; Bibiloni, Anibal G. [Departamento de Fisica-CONICET, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, C.C. 67, 1900 La Plata (Argentina); Freitag, Kristian [Helmholtz-Institut fuer Strahlen-und Kernphysik (H-ISKP) der Universitaet Bonn, Nussallee 14-16, D 53115 Bonn (Germany)

2007-02-01

The time-differential {gamma}-{gamma} perturbed-angular-correlation (PAC) technique with ion-implanted {sup 181}Hf tracers has been applied to study the hyperfine interactions of {sup 181}Ta impurities in the cubic bixbyite structure of Ho{sub 2}O{sub 3} and Eu{sub 2}O{sub 3}. The PAC experiments were performed in air in the temperature range 300-1373 K (in the case of Ho{sub 2}O{sub 3}) and 77-1273 K (in the case of Eu{sub 2}O{sub 3}). For both oxides, two electric-quadrupole interactions were found and attributed to the electric-field gradients (EFGs) acting on {sup 181}Ta probes substitutionally located at the two free-of-defects nonequivalent cation sites of the bixbyite structure. In the case of Ho{sub 2}O{sub 3}, two additional interactions were found in the temperature range 300-573 K. These results, as well as previous characterizations of the EFG at {sup 181}Ta sites in bixbyites, were compared to those obtained in experiments using {sup 111}Cd as probe, and to point-charge model calculations. Very recent ab initio predictions for the EFG tensor at impurities sites in binary oxides are also discussed. All these results enable us to discuss the validity of the widely used ionic model to describe the EFG in these highly ionic compounds.
Thickness dependence of magnetoelectric response for composites of Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} films on CoFe{sub 2}O{sub 4} ceramic substrates

Energy Technology Data Exchange (ETDEWEB)

Wang, Jing, E-mail: wang-jing@nuaa.edu.cn; Zhu, Kongjun [State Key Laboratory of Mechanics and Control of Mechanical Structures, College of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Wu, Xia; Deng, Chaoyong [School of Electronics and Information Engineering, Guizhou University, Guiyang 550025 (China); Peng, Renci; Wang, Jianjun [School of Materials Science and Engineering, and State Key Lab of New Ceramics and Fine Processing, Tsinghua University, Beijing 100084 (China)

2014-08-15

Using chemical solution spin-coating we grew Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} films of different thicknesses on highly dense CoFe{sub 2}O{sub 4} ceramics. X-ray diffraction revealed no other phases except Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} and CoFe{sub 2}O{sub 4}. In many of these samples we observed typical ferroelectric hysteresis loops, butterfly-shaped piezoelectric strains, and the magnetic-field-dependent magnetostriction. These behaviors caused appreciable magnetoelectric responses based on magnetic-mechanical-electric coupling. Our results indicated that the thickness of the Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} film was important in obtaining strong magnetoelectric coupling.
One-pot synthesis of a Ni–Mn{sub 3}O{sub 4} nanocomposite for supercapacitors

Energy Technology Data Exchange (ETDEWEB)

Xu, Guo-rong, E-mail: grxu@hnust.edu.cn; Shi, Jin-jin; Dong, Wen-hao; Wen, Ya; Min, Xiang-ping; Tang, An-ping

2015-05-05

Highlights: • Ni–Mn{sub 3}O{sub 4} nanocomposites have been synthesized simply. • Mn{sub 3}O{sub 4} particles were deposited on surface of Ni particles with OH functional groups. • Ni–Mn{sub 3}O{sub 4} composites could be quickly conditioned to birnessite-type MnO{sub 2}. • A specific capacitance of 230 F g{sup −1} was obtained for Ni (17.3%)–Mn{sub 3}O{sub 4} nanocomposite. - Abstract: Ni–Mn{sub 3}O{sub 4} nanocomposite has been prepared successfully by chemical oxidation in an alkaline solution of Mn{sup 2+} on the surface of Ni nanoparticles with OH functional groups using one-pot method. The obtained Ni–Mn{sub 3}O{sub 4} nanocomposite was characterized using a scanning electron microscope (SEM), a transmission electron microscope (TEM), X-ray diffraction (XRD) analysis and various electrochemical techniques, such as cyclic voltammetry (CV), galvanostatic charge/discharge (GC/D) and electrochemical impedance spectroscopy (EIS). The average crystal sizes of Mn{sub 3}O{sub 4} were found to decrease linearly with increasing Ni content in the Ni–Mn{sub 3}O{sub 4} composite. The Ni–Mn{sub 3}O{sub 4} nanocomposite could be easily conditioned and inverted to birnessite-type MnO{sub 2}. A specific capacitance of 230 F g{sup −1} (based on pure Mn{sub 3}O{sub 4}) was obtained for the Ni (17.3%)–Mn{sub 3}O{sub 4} nanocomposite at a current rate of 0.25 A g{sup −1}, and 94% of the initial capacitance was retained after 1000 GC/D cycles at a current rate of 1 A g{sup −1}. It is concluded that the Ni–Mn{sub 3}O{sub 4} nanocomposite is a promising electrode materials for supercapacitors.
Conversion of green emission into white light in Gd{sub 2}O{sub 3} nanophosphors

Energy Technology Data Exchange (ETDEWEB)

Jayasimhadri, M.; Ratnam, B.V. [Department of Physics, Changwon National University, Changwon, 641-773 (Korea, Republic of); Jang, Kiwan, E-mail: kwjang@changwon.ac.k [Department of Physics, Changwon National University, Changwon, 641-773 (Korea, Republic of); Lee, Ho Sueb [Department of Physics, Changwon National University, Changwon, 641-773 (Korea, Republic of); Yi, Soung-Soo [Department of Photonics, Silla University, Busan (Korea, Republic of); Jeong, Jung-Hyun [Department of Physics, Pukyong National University, Busan (Korea, Republic of)

2010-09-01

Gd{sub 2}O{sub 3} nanophosphors were prepared by combustion synthesis with and without doping of Dy{sup 3+} ions. The X-ray powder diffraction patterns indicate that as-prepared Gd{sub 2}O{sub 3} and 0.1 mol% Dy{sub 2}O{sub 3} doped Gd{sub 2}O{sub 3} nanophosphors have monoclinic structures. The transmission electron microscope (TEM) studies revealed that the as-prepared phosphors had an average crystallite sizes around 37 nm. The excitation and emission properties have been investigated for Dy{sup 3+} doped and undoped Gd{sub 2}O{sub 3} nanophosphors. New emission bands were observed in the visible region for Gd{sub 2}O{sub 3} nanophosphors without any rare earth ion doping under different excitations. A tentative mechanism for the origin of luminescence from Gd{sub 2}O{sub 3} host was discussed. Emission properties also measured for 0.1 mol% Dy{sup 3+} doped Gd{sub 2}O{sub 3} nanophosphors and found the characteristic Dy{sup 3+} visible emissions at 489 and 580 nm due to {sup 4}F{sub 9/2} {yields} {sup 6}H{sub 15/2} and {sup 4}F{sub 9/2} {yields} {sup 6}H{sub 13/2} transitions, respectively. The chromaticity coordinates were calculated based on the emission spectra of Dy{sup 3+} doped and undoped Gd{sub 2}O{sub 3} nanophosphors and analyzed with Commission Internationale de l'Eclairage (CIE) chromaticity diagram. These nanophosphors exhibit green color in undoped Gd{sub 2}O{sub 3} and white color after adding 0.1 mol% Dy{sub 2}O{sub 3} to Gd{sub 2}O{sub 3} nanophosphors under UV excitation. These phosphors could be a promising phosphor for applications in flat panel displays.
Electrospun ZnFe{sub 2}O{sub 4}-based nanofiber composites with enhanced supercapacitive properties

Energy Technology Data Exchange (ETDEWEB)

Agyemang, Frank Ofori; Kim, Hern, E-mail: hernkim@mju.ac.kr

2016-09-15

Highlights: • Electrospun ZnFe{sub 2}O{sub 4}-based nanofibers were successfully fabricated. • The electrochemical properties of ZnFe{sub 2}O{sub 4} were enhanced by addition of ZnO and Fe{sub 2}O{sub 3.} • A specific capacitance of 590 F g{sup −1} was achieved from a CV curve at a scan rate of 5 mV s{sup −1.} • The electrode materials poses excellent cycling stability even after 3000 cycles. - Abstract: Herein, we are reporting a facile method to synthesis ZnFe{sub 2}O{sub 4}-based nanofibers (ZnFe{sub 2}O{sub 4}, ZnO–ZnFe{sub 2}O{sub 4} and Fe{sub 2}O{sub 3}–ZnFe{sub 2}O{sub 4}) via the electrospinning technique using zinc acetonate and ferric acetonate as the metal oxide precursor and polyvinyl pyrrolidone (PVP) as the polymer. The as-prepared electrospun nanofiber composites were calcined at 500 °C to obtain crystalline porous nanofibers. The effect of different compositions on the morphology of each sample as well as their electrochemical properties when employed as electrode materials was studied. The results show that the as-prepared electrodes exhibited excellent performance with their specific capacitances calculated from the CV curves as 590, 490 and 450 F g{sup −1} for Fe{sub 2}O{sub 3}–ZnFe{sub 2}O{sub 4}, ZnO–ZnFe{sub 2}O{sub 4} and ZnFe{sub 2}O{sub 4} respectively at a scan rate of 5 mV s{sup −1}. Excellent stability of the electrodes was also observed even after 3000 cycles. The results obtained suggest these electrode materials might be promising candidates for supercapacitor application.
Electronic structure and optical properties of ABP{sub 2}O{sub 7} double phosphates

Energy Technology Data Exchange (ETDEWEB)

Hizhnyi, Yu. [Faculty of Physics, Kyiv National Taras Shevchenko University, 2, Block 1, Acad. Hlushkova Ave., 03680 Kyiv (Ukraine)], E-mail: hizhnyi@univ.kiev.ua; Gomenyuk, O.; Nedilko, S.; Oliynyk, A.; Okhrimenko, B. [Faculty of Physics, Kyiv National Taras Shevchenko University, 2, Block 1, Acad. Hlushkova Ave., 03680 Kyiv (Ukraine); Bojko, V. [National Agriculture University, 5 Geroiv Oborony Str., 03041 Kyiv (Ukraine)

2007-04-15

Luminescence and luminescence excitation under VUV radiation of ABP{sub 2}O{sub 7} (A=Na, K, Cs; B=Al, In) double phosphates are studied. Two emission bands peaking near 330 and 420 nm are common for investigated ABP{sub 2}O{sub 7} crystals. The band structure and partial densities of electronic states of perfect KAlP{sub 2}O{sub 7}, LiInP{sub 2}O{sub 7} and NaTiP{sub 2}O{sub 7} crystals are calculated by the full-potential linear-augmented-plane-wave (FLAPW) method. It is found that the structures of the conduction bands of ABP{sub 2}O{sub 7} crystals, which have different B cations, are appreciably different. Experimental results are compared with results of calculations of the electronic structure. Assumptions concerning the origin of luminescence in double phosphates are made.
Synthesis and characterization of reactions by nanoferrites Co{sub 2}Fe{sub 2}O{sub 4} combustion; Sintese por reacao de combustao e caracterizacao de nanoparticulas de Co{sub 2}Fe{sub 2}O{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Santos, P.T.A.; Dantas, B.B.; Costa, A.C.F.M.; Araujo, P.M.A.G., E-mail: polyanaquimica@yahoo.com.br [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Departamento de Engenharia de Materiais

2012-07-01

In this work CoFe{sub 2}O{sub 4} of magnetic nanoparticles were synthesized by combustion reaction and the structural and morphological characteristics of the synthesized samples as well as the parameters of synthesis temperature and reaction time were investigated in order to assess the reproducibility of the synthesis. The maximum temperature and time of the combustion flame were obtained with pyrometer coupled to a computer with online measurement and a stopwatch. The resulting samples were characterized by X-ray diffraction (XRD), infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The maximum temperature achieved during synthesis for all reactions ranged from 623 deg C and 755 deg C. The combustion flame time varied between 18 and 23 seconds. The XRD showed the formation of only CoFe{sub 2}O{sub 4} inverse spinel phase, with crystallite size 28 nm and crystallinity 78%, with typical morphology of the formation of agglomerates of uniform size, brittle and comprising nanoparticles together by weak forces. (author)
Electronic structures and Eu{sup 3+} photoluminescence behaviors in Y{sub 2}Si{sub 2}O{sub 7} and La{sub 2}Si{sub 2}O{sub 7}

Energy Technology Data Exchange (ETDEWEB)

Zhang Zhiya, E-mail: zhangzhiya@lzu.edu.cn [Department of Materials Science, School of Physical Science and Technology, Lanzhou University, Lanzhou, 730000 (China); Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou, 730000 (China); Wang Yuhua [Department of Materials Science, School of Physical Science and Technology, Lanzhou University, Lanzhou, 730000 (China); Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou, 730000 (China); Zhang Feng [Department of Materials Science, School of Physical Science and Technology, Lanzhou University, Lanzhou, 730000 (China); Cao Haining [Computational Science Center, Korea Institute of Science and Technology, Seoul, 136-791 (Korea, Republic of)

2011-04-14

Research highlights: > Host excitation near the band gap of Y{sub 2}Si{sub 2}O{sub 7} and La{sub 2}Si{sub 2}O{sub 7} is analyzed. > The calculated result well explains Eu{sup 3+} PL behaviors in Y{sub 2}Si{sub 2}O{sub 7} and La{sub 2}Si{sub 2}O{sub 7}. > The electronic structure and Eu{sup 3+} VUV PL in La{sub 2}Si{sub 2}O{sub 7} are first estimated. - Abstract: The electronic structures and linear optical properties of Y{sub 2}Si{sub 2}O{sub 7} (YSO) and La{sub 2}Si{sub 2}O{sub 7} (LSO) are calculated by LDA method based on the theory of DFT. Both YSO and LSO are direct-gap materials with the direct band gap of 5.89 and 6.06 eV, respectively. The calculated total and partial density of states indicate that in both YSO and LSO the valence band (VB) is mainly constructed from O 2p and the conduction band (CB) is mostly formed from Y 4d or La 5d. Both the calculated VB and CB of YSO exhibit relatively wider dispersion than that of LSO. In addition, the CB of YSO presents more electronic states. Meanwhile, the VB of LSO shows narrower energy distribution with higher electronic states density. The theoretical absorption of YSO shows larger bandwidth and higher intensity than that of LSO. The results are compared with the experimental host excitations and impurity photoluminescence in Eu{sup 3+}-doped YSO and LSO.
Photocatalytic performances and activities of Ag-doped CuFe{sub 2}O{sub 4} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Zhu, Zhengru, E-mail: zhengruzhu@gmail.com [Research Center of Hydrology and Water Source, School of Urban and Environment, Liaoning Normal University, Dalian, 116029 (China); State Key Laboratory of Fine Chemical, Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024 (China); Li, Xinyong; Zhao, Qidong [State Key Laboratory of Fine Chemical, Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024 (China); Li, Yonghua; Sun, Caizhi; Cao, Yongqiang [Research Center of Hydrology and Water Source, School of Urban and Environment, Liaoning Normal University, Dalian, 116029 (China)

2013-08-01

Graphical abstract: - Highlights: • CuFe{sub 2}O{sub 4} nanocrystals were synthesized by a co-precipitation method. • Ag/CuFe{sub 2}O{sub 4} catalyst was prepared by the wetness impregnation strategy. • The structural properties of Ag/CuFe{sub 2}O{sub 4} were investigated by XRD, TEM, DRS, and XPS techniques. • Ag/CuFe{sub 2}O{sub 4} has higher photocatalytic activity. - Abstract: In this work, CuFe{sub 2}O{sub 4} nanoparticles were synthesized by a chemical co-precipitation route. The Ag/CuFe{sub 2}O{sub 4} catalyst was prepared based on the CuFe{sub 2}O{sub 4} nanoparticles by the incipient wetness impregnation strategy, which showed excellent photoelectric property and catalytic activity. The structural properties of these samples were systematically investigated by X-ray powder diffraction (XRD), transmission electronic microscopy (TEM), UV–vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR) techniques. The photo-induced charge separation in the samples was demonstrated by surface photovoltage (SPV) measurement. The photocatalytic degradation of 4-CP by the Ag/CuFe{sub 2}O{sub 4} and CuFe{sub 2}O{sub 4} samples were comparatively studied under xenon lamp irradiation. The results indicate that the Ag/CuFe{sub 2}O{sub 4} sample exhibited the higher efficiency for the degradation of 4-CP.
The origins and behaviour of carbon in a major semi-arid river, the Murray River, Australia, as constrained by carbon isotopes and hydrochemistry

Energy Technology Data Exchange (ETDEWEB)

Cartwright, Ian, E-mail: ian.cartwright@monash.edu [School of Geosciences, Monash University, Clayton, Vic. 3800 (Australia)] [National Centre for Groundwater Research and Training, Flinders University, Adelaide SA 5001 (Australia)

2010-11-15

Research highlights: {yields} {delta}{sup 13}C and concentrations of DIC in Murray River controlled by mineralisation of organic carbon and evasion. {yields} Murray River is source of atmospheric CO{sub 2}. {yields} In-river processing of carbon results in difficulties in determining carbon sources. - Abstract: {delta}{sup 13}C values of dissolved inorganic C (DIC), dissolved organic C (DOC), and particulate organic C (POC) together with {delta}{sup 18}O and {delta}{sup 2}H values of water, {delta}{sup 34}S values of dissolved SO{sub 4}, and major ion concentrations were measured in the Murray River and its tributaries between November 2005 and April 2007 to constrain the origins and behaviour of riverine C. {delta}{sup 13}C{sub DIC} values in the Murray River vary between -9.5 and -4.7 per mille with a range of <3 per mille within any sampling round. {delta}{sup 13}C{sub DIC} values of the tributaries are -11.0 per mille to -5.1 per mille. DIC concentrations of the Murray River increase from {approx}25 mg/L in the middle and upper reaches of the river to 45-55 mg/L in the lower reaches. However, the mass ratio of DIC as a proportion of the total dissolved solids (TDS) decreases from {approx}0.6-0.7 in the headwaters to {approx}0.2-0.3 in the lower reaches of the river, with similar downstream changes in DIC/Cl ratios. This precludes simple evaporative concentration of DIC and is interpreted as the river evading CO{sub 2}; this interpretation is consistent with pCO{sub 2} values that are in the range 550-11,200 ppm volume (ppmv), which are far higher than those in equilibrium with the atmosphere ({approx}360 ppmv). The {delta}{sup 13}C{sub DIC} values are similar to those that would be produced by the weathering of marine limestone ({delta}{sup 13}C {approx} 0 per mille). However, the lack of marine limestones cropping out in the Murray-Darling Basin and the relatively uniform {delta}{sup 13}C{sub DIC} values of the Murray River (even in upland reaches where the

Structure and crystallization behavior of La{sub 2}O{sub 3}⋅3B{sub 2}O{sub 3} metaborate glasses doped with Nd{sup 3+} or Eu{sup 3+} ions

Energy Technology Data Exchange (ETDEWEB)

Pytalev, D.S., E-mail: pytalev@isan.troitsk.ru [Institute of Spectroscopy, Russian Academy of Sciences, 5 Fizicheskaya St., 142190 Troitsk, Moscow (Russian Federation); Caurant, D.; Majérus, O.; Trégouët, H. [Institut de Recherche de Chimie Paris, CNRS – Chimie ParisTech, 11 Rue Pierre et Marie Curie, 75005 Paris (France); Charpentier, T. [CEA, IRAMIS, NIMBE, CEA-CNRS UMR 3299, Laboratoire de Structure et Dynamique par Résonance Magnétique, 91191 Gif-sur-Yvette (France); Mavrin, B.N. [Institute of Spectroscopy, Russian Academy of Sciences, 5 Fizicheskaya St., 142190 Troitsk, Moscow (Russian Federation)

2015-08-25

Highlights: • The structure and crystallization behavior of the La{sub 2}O{sub 3}⋅3B{sub 2}O{sub 3} glass are studied. • LaB{sub 3}O{sub 6} crystallizes congruently without intermediate but only from glass surface. • The structure of the amorphous and the crystalline phases differ significantly. • The activation energy of LaB{sub 3}O{sub 6} crystal growth is determined. - Abstract: The local structure and crystallization behavior of the stoichiometric La{sub 2}O{sub 3}⋅3B{sub 2}O{sub 3} (LaMB) metaborate glass doped with Nd{sup 3+} or Eu{sup 3+} ions are studied using differential thermal analysis (DTA), X-ray diffraction (XRD), Raman scattering and {sup 11}B magic-angle spinning nuclear magnetic resonance (MAS NMR), optical absorbance and luminescence techniques. In the crystallized samples, XRD, NMR and Raman spectroscopy have detected the formation of only one crystalline phase (congruent crystallization of LaB{sub 3}O{sub 6}). No intermediate metastable crystalline phase has been detected before LaB{sub 3}O{sub 6} crystals formation (single stage crystallization process). The observation of heat treated glass samples by scanning electron microscopy (SEM) and optical microscopy coupled with the study of the effect of varying the glass particle size on the DTA curves have both revealed that LaB{sub 3}O{sub 6} crystallization only occurs by a heterogeneous nucleation mechanism (needle-shape crystals) from glass surface. The activation energy E{sub c} of crystal growth has been determined by performing DTA experiments at different heating rates with the Kissinger (784 kJ/mol) and Ozawa (801 kJ/mol) equations than can be used for surface crystallization processes. The heterogeneous crystallization behavior and the spectroscopic results obtained in this work by comparing the LaMB glass with the LaB{sub 3}O{sub 6} crystalline phase suggest the existence of significant structural differences between the amorphous and the crystalline phases contrary to what
Isotopic and chemical characterization of coal in Pakistan

International Nuclear Information System (INIS)

Qureshi, R.M.; Hasany, S.M.; Javed, T.; Sajjad, M.I.; Shah, Z.; Rehman, H.

1993-11-01

Stable carbon isotope ratios (delta/sup 13/C PDB) and toxic/trace element concentration levels are determined for Tertiary coal samples collected from seven coal fields in Pakistan. No systematic isotope effects are found in the process of coal liquefaction from peat to Tertiary lignites and sub bituminous coal. Similarly, no age effects are observed during the Tertiary regime. The observed variations in the carbon isotopic composition of coal obtained from 'Sharigh coal field' and the 'Sor-Range/Degari coal field' in Baluchistan are attributed to the depositional environments. More sampling of stable carbon isotope analysis are required to validate these observations. Significant concentrations of toxic elements such as S, Cr, Cd and Pb in Makarwal coal may pose environmental and engineering/operational problems for thermal power plants. (author)
The use of {sup 99m}Tc-Al{sub 2}O{sub 3} for detection of sentinel lymph nodes in breast cancer

Energy Technology Data Exchange (ETDEWEB)

Sinilkin, I., E-mail: sinilkinig@oncology.tomsk.ru; Chernov, V.; Medvedeva, A.; Zeltchan, R. [Tomsk Cancer Research Institute, Tomsk, 634050 (Russian Federation); Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation); Slonimskaya, E.; Doroshenko, A. [Tomsk Cancer Research Institute, Tomsk, 634050 (Russian Federation); Varlamova, N.; Skuridin, V. [Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation)

2016-08-02

Purpose: to study the feasibility of using the new radiopharmaceutical based on the technetium-99m-labeled gamma-alumina for identification of sentinel lymph nodes (SLNs) in breast cancer patients. The study included two groups of breast cancer patients who underwent single photon emission computed tomography (SPECT) and intraoperaive gamma probe identification of sentinel lymph nodes (SLNs). To identify SLNs, the day before surgery Group I patients (n = 34) were injected with radioactive {sup 99m}Tc-Al{sub 2}O{sub 3}, and Group II patients (n = 30) received {sup 99m}Tc-labeled phytate colloid. A total of 37 SLNs were detected in Group I patients. The number of identified SLNs per patient ranged from 1 to 2 (the average number of identified SLNs was 1.08). Axillary lymph nodes were the most common site of SLN localization. 18 hours after {sup 99m}Tc-Al{sub 2}O{sub 3} injection, the percentage of its accumulation in the SLN was 7–11% (of the counts in the injection site) by SPECT and 17–31% by gamma probe detection. In Group II SLNs were detected in 27 patients. 18 hours after injection of the phytate colloid the percentage of its accumulation in the SLN was 1.5–2% out of the counts in the injection site by SPECT and 4–7% by gamma probe. The new radiopharmaceutical based on the {sup 99m}Tc-Al{sub 2}O{sub 3} demonstrates high accumulation in SLNs without redistribution through the entire lymphatic basin. The sensitivity and specificity of {sup 99m}Tc-Al{sub 2}O{sub 3} were 100% for both SPECT and intraoperative gamma probe identification.
Epitaxial growth of Sc{sub 2}O{sub 3} films on Gd{sub 2}O{sub 3}-buffered Si substrates by pulsed laser deposition

Energy Technology Data Exchange (ETDEWEB)

Paulraj, Joseph; Wang, Rongping; Sellars, Matthew; Luther-Davies, Barry [Australian National University, Laser Physics Centre, Research School of Physics and Engineering, Acton, Canberra, ACT (Australia)

2016-04-15

We investigated the optimal conditions to prepare high-quality Sc{sub 2}O{sub 3} films on Gd{sub 2}O{sub 3}-buffered Si wafers using pulsed laser deposition technique with an aim at developing waveguide devices that can transform the performance of the gradient echo quantum memory based on bulk crystals. Under the optimal conditions, only oxide and Si (2 2 2) peaks appeared in the X-ray diffraction pattern. The Sc{sub 2}O{sub 3} (2 2 2) diffraction peak was located at 2θ=31.5 with a full width at half maxima (FWHM) of 0.16 , and its rocking curve had a FWHM of 0.10 . In-plane epitaxial relationship was confirmed by X-ray pole figure where Sc{sub 2}O{sub 3} (1 1 1) was parallel to Si (1 1 1). High-resolution TEM images indicated clear interfaces and perfect lattice images with sharp electron diffraction dots. All these results confirm that the oxide films on Si were single crystalline with high quality. (orig.)
Electronic properties of metal-In{sub 2}O{sub 3} interfaces

Energy Technology Data Exchange (ETDEWEB)

Nazarzadehmoafi, Maryam

2017-02-22

The behavior of the electronic properties of as-cleaved melt-grown In{sub 2}O{sub 3} (111) single crystals was studied upon noble metals, In and Sn deposition using angle-resolved photoemission spectroscopy. The stoichiometry, structural quality and crystal orientation, surface morphology, and the electron concentration were examined by energy dispersive X-ray spectroscopy, Laue diffraction, scanning tunneling microscopy (STM), and Hall-effect measurement, respectively. The similarity of the measured-fundamental and surface-band gaps reveals the nearly flat behavior of the bands at the as-cleaved surface of the crystals. Ag and Au/In{sub 2}O{sub 3} interfaces show Schottky behavior, while an ohmic one was observed in Cu, In, and Sn/In{sub 2}O{sub 3} contacts. From agreement of the bulk and surface band gaps, rectifying contact formation as well as the occurrence of photovoltage effect at the pristine surface of the crystals, it can be deduced that SEAL is not an intrinsic property of the as-cleaved surface of the studied crystals. Moreover, for thick Au and Cu overlayer regime at room temperature, Shockley-like surface states were observed. Additionally, the initial stage of Cu and In growth on In{sub 2}O{sub 3} was accompanied by the formation of a two dimensional electron gas (2DEG) fading away for higher coverages which are not associated with the earlier-detected 2DEG at the surface of In{sub 2}O{sub 3} thin films. The application of the Schottky-Mott rule, using in situ-measured work functions of In{sub 2}O{sub 3} and the metals, showed a strong disagreement for all the interfaces except for Ag/In{sub 2}O{sub 3}. The experimental data also disagree with more advanced theories based on the electronegativity concept and metal-induced gap states models.
Al{sub 2} O{sub 3}:Cr,Ni: a possible thermoluminescent dosemeter; Al{sub 2} O{sub 3}: Cr, Ni un posible dosimetro termoluminiscente

Energy Technology Data Exchange (ETDEWEB)

Mariani R, Francisco; Roman B, Alvaro; Saavedra S, Renato [Pontificia Univ. Catolica de Chile, Santiago (Chile). Facultad de Fisica; Ibarra S, Angel [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Madrid (Spain). Seccion Materiales para Fusion

1997-12-31

Results from a study on the thermoluminescent (Tl) emission from Al{sub 2} O{sub 3}:Cr,Ni are presented. The measurements were obtained for evaluation of the Al{sub 2} O{sub 3}:Cr,Ni dosimetric properties. Different crystal batches were exposed to two kind of ionizing radiation (X-ray and {beta}{sup -}). The Tl spectrum has a main peak with high thermal and optical stability, deviating from linearity for doses lower than 3.6 Gy. Furthermore, this material shows advantages (thermal resistance, reusability, multiple heating cycles) compared to TLD-100. Measured Al{sub 2} O{sub 3}:Cr,Ni properties indicate that it could be used as a dosemeter. (author). 5 refs., 4 figs.
Method for generating O.sub.2-rich gas from air using water

Science.gov (United States)

Nakano, Anna; Nakano, Jinichiro; Bennett, James P.

2018-01-30

The present disclosure is directed to a method for enriching an inlet air stream utilizing a number of enrichment sub-units connected in series, where each enrichment sub-unit conducts both a dissolution and degasification cycle. Each enrichment sub-unit comprises a compressor, an aeration unit, a deaeration unit, and a pump for the recirculation of water between the aeration and deaeration units. The methodology provides a manner in which the relationship between the respective Henry's coefficients of the oxygen and nitrogen in water may be exploited to enrich the O.sub.2 volume percent and diminish the N.sub.2 volume percent over repeated dissolution and degasification cycles. By utilizing a number of enrichment sub-units connected in series, the water contained in each enrichment sub-unit acts to progressively increase the O.sub.2 volume percent. Additional enrichment sub-units may be added and utilized until the O.sub.2 volume percent equals or exceeds a target O.sub.2 volume percent. In a particular embodiment, air having a general composition of about 78 vol. % N.sub.2 and 21 vol. % O.sub.2 is progressively enriched to provide a final mixture of about 92% vol. % O.sub.2 and 8% vol. % N.sub.2.
Method for generating O.sub.2-rich gas from air using water

Energy Technology Data Exchange (ETDEWEB)

Nakano, Anna; Nakano, Jinichiro; Bennett, James P.

2018-01-30

The present disclosure is directed to a method for enriching an inlet air stream utilizing a number of enrichment sub-units connected in series, where each enrichment sub-unit conducts both a dissolution and degasification cycle. Each enrichment sub-unit comprises a compressor, an aeration unit, a deaeration unit, and a pump for the recirculation of water between the aeration and deaeration units. The methodology provides a manner in which the relationship between the respective Henry's coefficients of the oxygen and nitrogen in water may be exploited to enrich the O.sub.2 volume percent and diminish the N.sub.2 volume percent over repeated dissolution and degasification cycles. By utilizing a number of enrichment sub-units connected in series, the water contained in each enrichment sub-unit acts to progressively increase the O.sub.2 volume percent. Additional enrichment sub-units may be added and utilized until the O.sub.2 volume percent equals or exceeds a target O.sub.2 volume percent. In a particular embodiment, air having a general composition of about 78 vol. % N.sub.2 and 21 vol. % O.sub.2 is progressively enriched to provide a final mixture of about 92% vol. % O.sub.2 and 8% vol. % N.sub.2.
The effects of de-humidification and O{sub 2} direct injection in oxy-PC combustion

Energy Technology Data Exchange (ETDEWEB)

Choi, C.G.; Na, I.H.; Lee, J.W.; Chae, T.Y.; Yang, W. [Korea Insitute of Industrial Technology, Seoul (Korea, Republic of). Energy System R and D Dept.

2013-07-01

This study is aimed to derive effects of de-humidification and O{sub 2} direct injection in oxy-PC combustion system. Temperature distribution and flue gas composition were observed for various air and oxy-fuel conditions such as effect of various O{sub 2} concentration of total oxidant, O{sub 2} concentration of primary stream and O{sub 2} direct injection through 0-D heat and mass balance calculation and experiments in the oxy-PC combustion system of 0.3 MW scale in KITECH (Korea Institute of Industrial Technology). Flame attachment characteristic related to O{sub 2} direct injection was also observed experimentally. We found that FEGT (furnace exit gas temperature) of 100% de-humidification to oxidizer is lower than humidification condition; difference between two conditions is lower than 20 C in all cases. The efficiency changing of combustion was negligible in O{sub 2} direct injection. But O{sub 2} direct injection should be carefully designed to produce a stable flame.
Facile hydrothermal synthesis of polyhedral Fe{sub 3}O{sub 4} nanocrystals, influencing factors and application in the electrochemical detection of H{sub 2}O{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Yuan Kefeng [College of Chemistry and Materials Science, Anhui Key Laboratory of Functional Molecular Solids, Anhui Normal University, Wuhu 241000 (China); Ni Yonghong, E-mail: niyh@mail.ahnu.edu.cn [College of Chemistry and Materials Science, Anhui Key Laboratory of Functional Molecular Solids, Anhui Normal University, Wuhu 241000 (China); Zhang Li [College of Chemistry and Materials Science, Anhui Key Laboratory of Functional Molecular Solids, Anhui Normal University, Wuhu 241000 (China)

2012-08-15

Highlights: Black-Right-Pointing-Pointer Fe{sub 3}O{sub 4} polyhedra had been successfully synthesized by a facile hydrothermal technology. Black-Right-Pointing-Pointer The as-obtained product exhibited the room-temperature ferrimagnetic property. Black-Right-Pointing-Pointer The final product could be prepared into an electrochemical sensor for the detection of H{sub 2}O{sub 2}. - Abstract: Polyhedral Fe{sub 3}O{sub 4} nanocrystals have been successfully synthesized by a facile hydrothermal technique, employing FeSO{sub 4}{center_dot}7H{sub 2}O, N{sub 2}H{sub 4} and NH{sub 3}{center_dot}H{sub 2}O as the reactants without the assistance of any surfactant. The phase of the as-obtained Fe{sub 3}O{sub 4} was characterized by X-ray powder diffraction (XRD) and further proved by Rietveld refinement of XRD data. Energy dispersive spectrometry (EDS) and scanning electron microscopy (SEM) were used for the composition and morphology analyses of the final product. Some factors influencing the formation of polyhedral Fe{sub 3}O{sub 4} nanocrystals were systematically investigated, including the reaction temperature and time, and the original volume ratio of NH{sub 3}{center_dot}H{sub 2}O/N{sub 2}H{sub 4}{center_dot}H{sub 2}O. It was found that the as-prepared Fe{sub 3}O{sub 4} polyhedra exhibited a good electrochemical property in 0.1 M phosphate buffer solution (PBS) with pH 7.0 and could be prepared into an electrochemical sensor for the detection of H{sub 2}O{sub 2}. The linear response range of the sensor was 10.0 Multiplication-Sign 10{sup -6} to 140.0 Multiplication-Sign 10{sup -6} M and a sensitivity was 11.05 {mu}A/mM. Furthermore, the room-temperature magnetic property of the product was also investigated.
Temperature-controlled formation of Anderson-type compounds and their conversion to [γ-Mo{sub 8}O{sub 26}]{sup 4-}-based variants using pendent ligands

Energy Technology Data Exchange (ETDEWEB)

Tian, Ai-xiang; Li, Ting-ting; Tian, Yan; Ni, Huai-ping; Ji, Xue-bin; Liu, Jia-ni; Liu, Guo-cheng; Ying, Jun [Bohai Univ., Jinzhou (China). Dept. of Chemistry

2017-10-01

By tuning the reaction temperature, two Anderson- and two [γ-Mo{sub 8}O{sub 26}]{sup 4-}-based compounds decorated by pendent organic ligands, [Cu{sup II}{sub 9}(bpz){sub 2}(pz){sub 2}(H{sub 2}O){sub 24}]-[H{sub 2}(Cr(OH){sub 5}Mo{sub 6}O{sub 19}){sub 4}].11H{sub 2}O (1), [Cu{sup II}(bpz){sub 2}(H{sub 2}O){sub 2}(γ-H{sub 4}-Mo{sub 8}O{sub 26})].2H{sub 2}O (2), [Cu{sup II}{sub 2}(tea){sub 2}(H{sub 2}O){sub 6}(HCr(OH){sub 6}Mo{sub 6}O{sub 18}){sub 2}]. 6H{sub 2}O (3) and [Ag{sup I}(bpz)(H{sub 2}O)(γ-H{sub 4}Mo{sub 8}O{sub 26}){sub 0.5}] (4) (bpz=4-butyl-1H-pyrazole, pz=1H-pyrazole, tea=2-[1,2,4]triazol-4-yl-ethylamine), have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction analysis, IR spectra and elemental analyses. In compound 1, there are two kinds of tri-nuclear Cu{sup II} clusters induced by bpz and pz ligands, respectively. Four Anderson-type anions are linked by these tri-nuclear clusters to form a ''W''-type subunit. In compound 2, the [Cu(bpz){sub 2}(H{sub 2}O){sub 2}]{sup 2+} subunits connect the γ-Mo{sub 8} anions to construct a chain. The remaining two non-coordinated N donors in [Cu(bpz){sub 2}(H{sub 2}O){sub 2}]{sup 2+} further link two adjacent γ-Mo{sub 8} anions through Mo-N bonds. In compound 3, there exists a bi-nuclear Cu{sup II} cluster [Cu{sub 2}(tea){sub 2}(H{sub 2}O){sub 6}]{sup 4+}. The discrete bi-nuclear Cu{sup II} clusters and the CrMo{sub 6} anions link each other through abundant hydrogen bonding interactions. In compound 4, the [Ag(bpz)(H{sub 2}O)]{sup +} subunits connect γ-Mo{sub 8} anions to build a zigzag chain. The chains are further fused by other [Ag(bpz)(H{sub 2}O)]{sup +} cations to form a grid-like layer. There still exist Mo-N bonds in 4. We also have investigated the electrochemical and photocatalytic properties of 1-4.
Separation of valence states in thin films with mixed V{sub 2}O{sub 5} and V{sub 7}O{sub 16} phases

Energy Technology Data Exchange (ETDEWEB)

Huotari, J., E-mail: jonihuot@ee.oulu.fi [Faculty of Information Technology and Electrical Engineering, University of Oulu, P.O. Box 4500, FI-90014 Oulu (Finland); Cao, W. [Research Centre for Molecular Materials, University of Oulu, P.O. Box 3000, FI-90014 Oulu (Finland); Niu, Y. [MAX-lab, Lund University, SE-221 00 Lund (Sweden); Lappalainen, J.; Puustinen, J. [Faculty of Information Technology and Electrical Engineering, University of Oulu, P.O. Box 4500, FI-90014 Oulu (Finland); Pankratov, V. [Research Centre for Molecular Materials, University of Oulu, P.O. Box 3000, FI-90014 Oulu (Finland); Lloyd Spetz, A. [Faculty of Information Technology and Electrical Engineering, University of Oulu, P.O. Box 4500, FI-90014 Oulu (Finland); Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping (Sweden); Huttula, M. [Research Centre for Molecular Materials, University of Oulu, P.O. Box 3000, FI-90014 Oulu (Finland)

2016-08-15

Highlights: • Films have different XPS and NEXAFS spectra depending on the crystal structure. • Difference in oxygen vacancy concentration between the different films is identified. • Connection between high gas sensitivity and surface state of the films is revealed. - Abstract: Among the other applications, vanadium oxide thin films are considered to be excellent candidates for gas sensing. To understand the origins of the sensing capability, we carried out X-ray photoelectron and X-ray absorption spectroscopy measurements to determinate the surface valence states of thin films with mixed V{sub 7}O{sub 16} and V{sub 2}O{sub 5} compounds. Thin films were fabricated by pulsed laser deposition, and the crystal structure and symmetry of the deposited films was studied using grazing incidence X-ray diffraction and Raman spectroscopy. These results together with X-ray photoelectron and absorption spectra showed that the thin-film crystal structures varied between orthorhombic V{sub 2}O{sub 5} phase and another phase of triclinic V{sub 7}O{sub 16}. X-ray photoelectron spectroscopy was used to quantitatively confirm the high amount of V{sup 4+} ions on surfaces of the films, especially of films with V{sub 7}O{sub 16} phase present. This result was confirmed in the quantitative analysis of the V2p near-edge X-ray absorption spectra. Through the observed electronic structures, it was found that in addition to unique crystal structure and morphology, the enhanced gas sensitivity of these layers is attributed to the increase in the amount of surface oxygen vacancies.
Preparation and photocatalytic activity of ZnO/Fe{sub 2}O{sub 3} nanotube composites

Energy Technology Data Exchange (ETDEWEB)

Liu, Yanjun; Sun, Li; Wu, Jiagen; Fang, Ting; Cai, Ran; Wei, Ang, E-mail: wei1177@126.com

2015-04-15

Highlights: • ZnO/Fe{sub 2}O{sub 3} tubular structure was prepared via photochemical deposition at RT. • The composites show a great improvement in photocatalytic characteristics. • The possible reasons of photocatalytic performance of composites were researched. • The formation mechanism of ZnO/Fe{sub 2}O{sub 3} tubular structure was discussed. - Abstract: Fe{sub 2}O{sub 3} nanoparticles were grown on ZnO nanorods (NRs) to form ZnO/Fe{sub 2}O{sub 3} nanotube (NT) composites via photochemical deposition under ultraviolet light irradiation at a room temperature. Fe{sup 3+} ions in the solution preferentially adhere to the metastable Zn-rich (0 0 0 1) polar surfaces in ZnO NRs, which leading to the formation of ZnO/Fe{sub 2}O{sub 3} NTs. ZnO/Fe{sub 2}O{sub 3} NT nanocomposites show a great improvement in photocatalytic characteristics compared with the bare ZnO NRs. It can be inferred that the enhanced photocatalytic performance of ZnO/Fe{sub 2}O{sub 3} is benefit from the synergistic effect of ZnO and Fe{sub 2}O{sub 3} semiconductors.
Green fabrication of agar-conjugated Fe{sub 3}O{sub 4} magnetic nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Hsieh, S; Huang, B Y; Lin, P Y; Chang, C W [Department of Chemistry and Center for Nanoscience and Nanotechnology, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (China); Hsieh, S L [Department of Seafood Science, National Kaohsiung Marine University, Kaohsiung 81157, Taiwan (China); Wu, C C [Department of Nutrition and Health Sciences, Chang Jung Christian University, Tainan 71101, Taiwan (China); Wu, C H [Department of Computer Science and Information Engineering, National University of Kaohsiung, Kaohsiung 80811, Taiwan (China); Huang, Y S, E-mail: shsieh@facmail.NSYSU.edu.tw [Department of Food Science and Technology, Tajen University, Pingtung 90741, Taiwan (China)

2010-11-05

Magnetic nanoparticles are of great interest both for fundamental research and emerging applications. In the biomedical field, magnetite (Fe{sub 3}O{sub 4}) has shown promise as a hyperthermia-based tumor therapeutic. However, preparing suitable solubilized magnetite nanoparticles is challenging, primarily due to aggregation and poor biocompatibility. Thus methods for coating Fe{sub 3}O{sub 4} NPs with biocompatible stabilizers are required. We report a new method for preparing Fe{sub 3}O{sub 4} nanoparticles by co-precipitation within the pores of agar gel samples. Permeated agar gels were then dried and ground into a powder, yielding agar-conjugated Fe{sub 3}O{sub 4} nanoparticles. Samples were characterized using XRD, FTIR, TGA, TEM and SQUID. This method for preparing agar-coated Fe{sub 3}O{sub 4} nanoparticles is environmentally friendly, inexpensive and scalable.
Processing and characterisation of novel metal-reinforced Al{sub 2}O{sub 3}-composites; Herstellung und Charakterisierung neuartiger metallverstaerkter Al{sub 2}O{sub 3}-Verbundwerkstoffe

Energy Technology Data Exchange (ETDEWEB)

Guenther, R. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Werkstofforschung

1999-07-01

Using a new processing route, Al{sub 2}O{sub 3}-based ceramic composites have been prepared, that consist of 3-d networks of the ceramic and different metallic phases. The damage tolerance of these composites could be significantly improved over monolithic Al{sub 2}O{sub 3}: fracture strength and fracture toughness were increased by a factor of 4 up to 1393 MPa and 11.8 MPa {radical}(m), respectively. Similarly, resistance against abrasive wear was successfully improved by a factor of two over monolithic Al{sub 2}O{sub 3}. In combination with the good electrical and thermal conductivity, these superior mechanical properties are of great interest for automotive and biomedical industries. (orig.) [German] Mit einem neu entwickelten Verfahren werden keramische Al{sub 2}O{sub 3}-Verbundwerkstoffe hergestellt, die sich durch eine dreidimensionale Vernetzung der (inter)metallischen und der keramischen Phase auszeichnen. Die Schadenstoleranz derartiger Verbundwerkstoffe konnte im Vergleich zu monolithischer Al{sub 2}O{sub 3}-Keramik deutlich gesteigert werden: Die Bruchfestigkeit und die Bruchzaehigkeit wurden jeweils um einen Faktor 4 auf 1393 MPa bzw. 11,8 MPa {radical}(m) erhoeht, die Abriebfestigkeit um einen Faktor 2 verbessert. In Kombination mit der elektrischen und thermischen Leitfaehigkeit sind diese aussergewoehnlichen mechanischen Eigenschaften in Automobilbau und in der Medizintechnik von grossem Interesse. (orig.)
Alternative route for the synthesis of high surface-area η-Al{sub 2}O{sub 3}/Nb{sub 2}O{sub 5} catalyst from aluminum waste

Energy Technology Data Exchange (ETDEWEB)

Nogueira, Francisco G.E. [Departamento de Engenharia Química, Universidade Federal de São Carlos, CEP 13565-905, São Carlos, SP (Brazil); Asencios, Yvan J.O. [Departamento de Ciências do Mar, Universidade Federal de São Paulo, Av. Alm. Saldanha da Gama, 89, 11030-400, Santos, SP (Brazil); Rodella, Cristiane B. [Laboratório Nacional de Luz Sincrotron, Rua Giuseppe Máximo Scolfaro, 10.000 Polo II de Alta Tecnologia, 13083-970, Campinas, SP (Brazil); Porto, André L.M. [Departamento de Engenharia Química, Universidade Federal de São Carlos, CEP 13565-905, São Carlos, SP (Brazil); Assaf, Elisabete M., E-mail: eassaf@iqsc.usp.br [Instituto de Química de São Carlos, Universidade de São Paulo, Av. Trabalhador São Carlense, 400, 13560-970, São Carlos, SP (Brazil)

2016-12-01

This paper describes an alternative route for the production of a high-surface-area η-Al{sub 2}O{sub 3}/Nb{sub 2}O{sub 5} catalyst synthesized from aluminum waste and niobium ammonium oxalate (NH{sub 4}H{sub 2}[NbO−(C{sub 2}O{sub 4}){sub 3}]·3H{sub 2}O). The effects of thermal treatment on the morphology and crystal structure were examined by X-ray powder diffraction (XPD), surface area measurements (BET), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray fluorescence, dynamic scanning calorimetry (DSC) and thermogravimetry (TG) measurement. The catalysts were evaluated in the glycerol dehydration reaction. Catalytic tests were carried out with reactants in gas-phase with a fixed-bed reactor at 300° and 400 °C. - Highlights: • Alternative route for the production of a high-surface-area Al{sub 2}O{sub 3}/Nb{sub 2}O{sub 5} catalyst. • The catalyst was synthesized from aluminum waste and ammonium oxalato-niobate. • NbAl catalyst obtained showed high specific surface area (330 m{sup 2}/g). • The catalyst produced by this method showed promise in the dehydration of glycerol.
Structure of the non-superconducting phase La/sub 3/Ba/sub 3/Cu/sub 6/Osub(14+ x) and its relation to the high - Tc superconductor YBa/sub 2/Cu/sub 3/Osub(7 -delta)

Energy Technology Data Exchange (ETDEWEB)

David, W.I.F.; Harrison, W.T.A.; Ibberson, R.M.; Grasmeder, J.R.; Lanchester, P.

1987-07-23

The authors report time-of-flight neutron powder diffraction results, which confirm that the structure of La/sub 3/Ba/sub 3/Cu/sub 6/Osub(14 + x) is isomorphous with the tetragonal variant of YBa/sub 2/Cu/sub 3/Osub(7-delta); in particular, the copper coordination and calculated valencies of both compounds agree closely. The apparent contradiction of stoichiometries between these two phases is resolved by ordering of the large cations consistent with a formulation La(Lasub(0.25)Basub(0.75))/sub 2/Cu/sub 3/Osub(7 + 1/2x). The present results indicate that there is a remarkable structural stability from RA/sub 2/Cu/sub 3/O/sub 6/ to RA/sub 2/Cu/sub 3/Osub(7.2), although superconductivity appears to be confined to the range RA/sub 2/Cu/sub 3/Osub(6.5) to Ra/sub 2/Cu/sub 3/O/sub 7/.
Chemistry of fluids from a natural analogue for a geological CO{sub 2} storage site (Montmiral, France): Lessons for CO{sub 2}-water-rock interaction assessment and monitoring

Energy Technology Data Exchange (ETDEWEB)

Pauwels, Helene [BRGM - Water Division, 3, av Claude Guillemin, 45060 Orleans Cedex (France)], E-mail: h.pauwels@brgm.fr; Gaus, Irina; Le Nindre, Yves Michel [BRGM - Water Division, 3, av Claude Guillemin, 45060 Orleans Cedex (France); Pearce, Jonathan [British Geological Survey, Kingsley Dunham Centre, Keyworth, Nottingham NG125GG (United Kingdom); Czernichowski-Lauriol, Isabelle [BRGM - Water Division, 3, av Claude Guillemin, 45060 Orleans Cedex (France)

2007-12-15

Chemical and isotope studies of natural CO{sub 2} accumulations aid in assessing the chemical effects of CO{sub 2} on rock and thus provide a potential for understanding the long-term geochemical processes involved in CO{sub 2} geological storage. Several natural CO{sub 2} accumulations were discovered during gas and oil exploration in France's carbogaseous peri-Alpine province (south-eastern France) in the 1960s. One of these, the Montmiral accumulation at a depth of more than 2400 m, is currently being exploited. The chemical composition of the water collected at the wellhead has changed in time and the final salinity exceeds 75 g/L. These changes in time can be explained by assuming that the fraction of the reservoir brine in the recovered brine-CO{sub 2}-H{sub 2}O mixture varies, resulting in variable proportions of H{sub 2}O and brine in the sampled water. The proportions can be estimated in selected samples due to the availability of gas and water flowrate data. These data enabled the reconstruction of the chemical and isotope composition of the brine. The proportions of H{sub 2}O and brine can also be estimated from isotope ({delta}{sup 2}H, {delta}{sup 18}O) composition of collected water and {delta}{sup 18}O of the sulfates or CO{sub 2}. The reconstituted brine has a salinity of more than 85 g/L and, according to its Br{sup -} content and isotope ({delta}{sup 2}H, {delta}{sup 18}O, {delta}{sup 34}S) composition, originates from an evaporated Triassic seawater that underwent dilution by meteoric water. The reconstitution of the brine's chemical composition enabled an evaluation of the CO{sub 2}-water-rock interactions based on: (1) mineral saturation indices; and (2) comparison with initial evaporated Triassic seawater. Dissolution of K- and SO{sub 4}-containing minerals such as K-feldspar and anhydrite, and precipitation of Ca and Mg containing minerals that are able to trap CO{sub 2} (carbonates) are highlighted. The changes in concentration of
Moessbauer study in the glass system PbO. 2B/sub 2/O/sub 3/. Fe/sub 2/O/sub 3/

Energy Technology Data Exchange (ETDEWEB)

Sekhon, S S; Kamal, R [Punjabi Univ., Patiala (India). Dept. of Physics

1978-05-01

The Moessbauer technique has been employed to study the structure and crystallite formation in the glass system PbO.2B/sub 2/O/sub 3/ containing upto 30 wt% Fe/sub 2/O/sub 3/. Like alkali borate glasses, this glass system also exhibits a broadened quadrupole doublet and iron ions are present in Fe/sup 3 +/ state. Above about 20 wt%, the crystallites of magnetically ordered states have been identified. Susceptibility variation with concentration suggests the formation of a superparamagnetic state.
The structure of the non-superconducting phase La3Ba3Cu6Osub(14+ x) and its relation to the high - Tc superconductor YBa2Cu3Osub(7 -delta)

International Nuclear Information System (INIS)

David, W.I.F.; Harrison, W.T.A.; Ibberson, R.M.; Grasmeder, J.R.; Lanchester, P.

1987-01-01

The authors report time-of-flight neutron powder diffraction results, which confirm that the structure of La 3 Ba 3 Cu 6 Osub(14+x) is isomorphous with the tetragonal variant of YBa 2 Cu 3 Osub(7-delta); in particular, the copper coordination and calculated valencies of both compounds agree closely. The apparent contradiction of stoichiometries between these two phases is resolved by ordering of the large cations consistent with a formulation La(Lasub(0.25)Basub(0.75)) 2 Cu 3 Osub(7+1/2x). The present results indicate that there is a remarkable structural stability from RA 2 Cu 3 O 6 to RA 2 Cu 3 Osub(7.2), although superconductivity appears to be confined to the range RA 2 Cu 3 Osub(6.5) to Ra 2 Cu 3 O 7 . (author)

Hydrogen permeation on Al{sub 2}O{sub 3}-based nickel/cobalt composite membranes

Energy Technology Data Exchange (ETDEWEB)

Park, Jihee; Jung, Miewon [Department of Chemistry/Institute of Basic Science, Sungshin Women' s University, Seoul 136-742 (Korea, Republic of); Hong, Tae-Whan [Department of Materials Science and Engineering/Research Center for Sustainable Eco-Devices and Materials(ReSEM), Chungju National University, Chungju 380-702 (Korea, Republic of)

2010-12-15

Al{sub 2}O{sub 3} was synthesized using the sol-gel process with aluminum isopropoxide as the precursor and primary distilled water as the solvent. Nickel and cobalt metal powders were used to increase the strength of the membranes. The Al{sub 2}O{sub 3}-based membranes were prepared using HPS following a mechanical alloying process. The phase transformation, thermal evolution, surface and cross-section morphology of Al{sub 2}O{sub 3} and Al{sub 2}O{sub 3}-based membranes were characterized by XRD, TG-DTA and FE-SEM. The hydrogen permeation of Al{sub 2}O{sub 3}-based membranes was examined at 300-473 K under increasing pressure. Hydrogen permeation flux through an Al{sub 2}O{sub 3}-20wt%Co membrane was obtained to 2.36 mol m{sup -2} s{sup -1}. Reaction enthalpy was calculated to 4.5 kJ/mol using a Van't Hoff's plot. (author)
Production and characterization of compounds based on MgB{sub 4}O{sub 7} for application in dosimetry; Producao e caracterizacao de compostos a base de MgB{sub 4}O{sub 7} para aplicacao em dosimetria

Energy Technology Data Exchange (ETDEWEB)

Souza, Luiza Freire de

2016-07-01

Many materials with luminescent properties are used for ionizing radiation dosimetry through the thermoluminescence (TL) and optically stimulated luminescence (OSL) techniques. Detectors based on lithium fluoride (LiF), calcium sulphate (CaSO{sub 4}) and aluminum oxide (Al{sub 2}O{sub 3}), doped or codoped with various elements, are the TL or OSL commercial dosimeters most widely used currently. However, several researches are focused to the development of new TL /OSL materials in intention to enhance the dosimetric properties, in view that no TL/OSL dosimeter has all the ideal characteristics for monitoring the radiation. In this context, magnesium tetraborate (MgB{sub 4}O{sub 7}), which has been presented in the literature as a material for dosimetry TL, was investigated in this work. As there are no reports on the structural characterization of this material or regarding to its applicability on OSL dosimetry, the proposal of the present work was to develop compounds based on MgB{sub 4}O{sub 7}, with different doping, by solid state synthesis. It was made the structural, optical, TL and OSL characterization of the compound to verify it feasibility for application on radiation dosimetry. Initially, it was determined the calcination temperature and time for MgB{sub 4}O{sub 7} formation, with the use of thermal analyses and x ray diffraction. The ideal calcination was found at 900 °C for 7 hours. It were produced , in powder form, the compounds: MgB{sub 4}O{sub 7}, MgB{sub 4}O{sub 7}:Dy, MgB{sub 4}O{sub 7}:Dy,Li, MgB{sub 4}O{sub 7}:Ce, MgB{sub 4}O{sub 7}:Ce,Li, MgB{sub 4}O{sub 7}:Nd and MgB{sub 4}O{sub 7}:Nd,Li. For TL and OSL analyses it were produced pellets sintering at 950 °C for 2 hours. The radioluminescence (RL) analyses of MgB{sub 4}O{sub 7}:Dy and MgB{sub 4}O{sub 7}:Dy,Li shows wavelength emissions at 490, 590, 670 and 760 nm. For MgB{sub 4}O{sub 7}:Ce and MgB{sub 4}O{sub 7}:Ce,Li RL was observed wide emission band in the ultraviolet region. For the Mg
A urinary metabolite of {Delta}{sup 1}-tetrahydrocannabinol. The first synthesis of 4``-hydroxy-{Delta}{sup 1}-tetrahydrocannabinol-7-oic acid labelled with deuterium

Energy Technology Data Exchange (ETDEWEB)

Szirmai, Maria; Odqvist, Helena [Uppsala Univ. (Sweden). Dept. of Pharmacognosy; Halldin, M.M. [Karolinska Inst., Stockholm (Sweden). Dept. of Pharmacology

1996-04-01

The first synthesis of 4``-hydroxy-{Delta}-{sup 1}-THC-7-oic acid, one of the three major metabolites of {Delta}{sup 1}-THC identified in human urine is discussed. Methyl 4-(3,5-dihydroxyphenyl)butanoate was prepared from 3,5-diydroxybenzoic acid in an overall yield of 15% was condensed with a terpene synthon under acidic conditions followed by hydrolysis and conversion of the 4``-carboxylic acid function to the corresponding methyl ketone using methyllithium. Reduction with NaBH{sub 4} afforded the secondary alcohol in the side-chain. Acetylation and removal of the 1,3-dithiane masking group gave the aldehyde in C-7-position which was further oxidized using NaClO{sub 2} followed by deacetylation to give the desired metabolite. The same procedure may be used for the synthesis of unlabelled 4``-hydroxy-{Delta}{sup 1}-THC-7-oic acid. (author).
BioMagResBank (BMRB) as a partner in the Worldwide Protein Data Bank (wwPDB): new policies affecting biomolecular NMR depositions

International Nuclear Information System (INIS)

Markley, John L.; Ulrich, Eldon L.; Berman, Helen M.; Henrick, Kim; Nakamura, Haruki; Akutsu, Hideo

2008-01-01

We describe the role of the BioMagResBank (BMRB) within the Worldwide Protein Data Bank (wwPDB) and recent policies affecting the deposition of biomolecular NMR data. All PDB depositions of structures based on NMR data must now be accompanied by experimental restraints. A scheme has been devised that allows depositors to specify a representative structure and to define residues within that structure found experimentally to be largely unstructured. The BMRB now accepts coordinate sets representing three-dimensional structural models based on experimental NMR data of molecules of biological interest that fall outside the guidelines of the Protein Data Bank (i.e., the molecule is a peptide with 23 or fewer residues, a polynucleotide with 3 or fewer residues, a polysaccharide with 3 or fewer sugar residues, or a natural product), provided that the coordinates are accompanied by representation of the covalent structure of the molecule (atom connectivity), assigned NMR chemical shifts, and the structural restraints used in generating model. The BMRB now contains an archive of NMR data for metabolites and other small molecules found in biological systems
Photochemical degradation of diethyl phthalate with UV/H{sub 2}O{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Xu Bin [State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Gao Naiyun [State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China)]. E-mail: gaonaiyun@mail.tongji.edu.cn; Sun Xiaofeng [State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Xia Shengji [State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Rui Min [State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Simonnot, Marie-Odile [Laboratory of Chemical Engineering Science, CNRS-INPL, 1 rue Grandville, BP451, F-54001 Nancy Cedex (France); Causserand, Christel [Laboratory of Chemical Engineering, UMR 5503 CNRS INP, Universite Paul Sabatier, 31062 Toulouse Cedex 9 (France); Zhao Jianfu [State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China)

2007-01-02

The decomposition of diethyl phthalate (DEP) in water using UV-H{sub 2}O{sub 2} process was investigated in this paper. DEP cannot be effectively removed by UV radiation and H{sub 2}O{sub 2} oxidation alone, while UV-H{sub 2}O{sub 2} combination process proved to be effective and could degrade this compound completely. With initial concentration about 1.0 mg/L, more than 98.6% of DEP can be removed at time of 60 min under intensity of UV radiation of 133.9 {mu}W/cm{sup 2} and H{sub 2}O{sub 2} dosage of 20 mg/L. The effects of applied H{sub 2}O{sub 2} dose, UV radiation intensity, water temperature and initial concentration of DEP on the degradation of DEP have been examined in this study. Degradation mechanisms of DEP with hydroxyl radicals oxidation also have been discussed. Removal rate of DEP was sensitive to the operational parameters. A simple kinetic model is proposed which confirms to pseudo-first order reaction. There is a linear relationship between rate constant k and UV intensity and H{sub 2}O{sub 2} concentration.
{delta}{sup 13}C of Tree-Ring Lignin as an Indirect Measure of Climate Change

Energy Technology Data Exchange (ETDEWEB)

Robertson, I. [CSIR Environmentek, Quaternary Dating Research Unit (South Africa)], E-mail: i.robertson@swansea.ac.uk; Loader, N. J.; McCarroll, D. [University of Wales Swansea, Department of Geography (United Kingdom); Carter, A. H. C. [University of Cambridge, Godwin Institute for Quaternary Research (United Kingdom); Cheng, L.; Leavitt, S. W. [University of Arizona, Laboratory of Tree-Ring Research (United States)

2004-06-15

High-resolution paleoclimatic data are an essential requirement for testing numerical models of climate change and the global carbon cycle. If the long tree-ring chronologies, originally established for the purpose of dendrochronology, are to be fully exploited as an indirect measure of past climatic variability, additional techniques are required to obtain this information. The determination of the {delta}{sup 13}C value of tree-ring cellulose has been used successfully to reconstruct past climates. However, under both aerobic and anaerobic conditions, the polysaccharide components of vascular plants (mainly cellulose and hemicelluloses) are more prone to rapid degradation than lignin. This has serious implications for the use of carbon isotope values of tree-ring cellulose as an indirect measure of past climates. An absolutely dated ring-width chronology was established for oaks (Quercus robur L.) growing at Sandringham Park in eastern England. Carbon isotope values were determined on {alpha}-cellulose and 'Klason' lignin isolated from annual latewood samples over the period AD 1895-1999. The carbon isotope values of earlywood lignin are correlated with the latewood carbon isotope values of the previous year, supporting the theory that some of the carbon utilised in earlywood synthesis is assimilated in the previous year. The high-frequency variance in the carbon isotope indices of latewood lignin and cellulose is highly correlated with combined July and August environmental variables, indicating that they were formed at similar times. There was no evidence of secondary lignification. These results demonstrate that the determination of carbon isotope values of latewood lignin offers the potential to obtain unambiguous proxy climatic data covering several millennia.
The ‘sub’ metallide oxide hydrides Sr{sub 21}Si{sub 2}O{sub 5}H{sub 12+x} and Ba{sub 21}M{sub 2}O{sub 5}H{sub 12+x} (M = Zn, Cd, Hg, In, Tl, Si, Ge, Sn, Pb, As, Sb, Bi)

Energy Technology Data Exchange (ETDEWEB)

Jehle, Michael; Hoffmann, Anke [Institut für Anorganische und Analytische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, D-79104 Freiburg (Germany); Kohlmann, Holger [Institut für Anorganische Chemie, Universität Leipzig, Johannisallee 29, D-04103 Leipzig (Germany); Scherer, Harald [Institut für Anorganische und Analytische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, D-79104 Freiburg (Germany); Röhr, Caroline, E-mail: caroline@ruby.chemie.uni-freiburg.de [Institut für Anorganische und Analytische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, D-79104 Freiburg (Germany)

2015-02-25

Highlights: • The sub metallide oxide hydrides (Sr/Ba){sub 21}M{sub 2}O{sub 5}H{sub 12+x} were prepared for 14 M elements. • M covers a wide range of elements, from the Zn group to the pentels. • The ionic partial structure contains isolated M anions and suboxide clusters [O{sub 5}A{sub 18}]. • The H-content was determined by neutron diffraction and {sup 1}H/{sup 2}D MAS-NMR spectroscopy. • Band structure calculations support the H/D content and distribution. - Abstract: The title compounds sporting a great variety of anions M of different formal charges have been synthesized from melts of the composition A:M:O:H/D = 21:2:5:24, using BaH{sub 2}/SrH{sub 2} as hydrogen sources. All phases were characterized by means of single crystal X-ray data [cubic, space group Fd3{sup ¯}m; Sr{sub 21}Si{sub 2}O{sub 5}H{sub 12+x}: a = 1911.90(1) pm, R1 = 0.0201; for the barium phases with Zn (a = 2041.7(3) pm, R1 = 0.077), Cd (a = 2063.3(1) pm, R1 = 0.051), Hg (a = 2050.7(1) pm, R1 = 0.059), In (a = 2060.7(1) pm, R1 = 0.101), Tl (a = 2068.1(10) pm, R1 = 0.0485), Si (a = 2033.6(1) pm, R1 = 0.045), Ge (a = 2035.6(1) pm, R1 = 0.037), Sn (a = 2053.2(2) pm, R1 = 0.054), Pb (a = 2059.7(1) pm, R1 = 0.056), As (a = 2023.0(3) pm, R1 = 0.087), Sb (a = 2041.9(1) pm, R1 = 0.067) and Bi (a = 2045.9(1) pm, R1 = 0.075)]. Neutron powder diffraction data collected for the Ba silicide (both H and D compound) were refined by the Rietveld method (a = 2037.0(1), R{sub p} = 0.0173; wR{sub p} = 0.0304, R(F{sup 2}) = 0.086). The statistically occupied (H/D)(1) site 96g, which corresponds to the carbon position inSr{sub 21}Si{sub 2}O{sub 5}C{sub 6}, together with two further sparsely occupied sites (H/D)(2,3), yields the overall composition Ba{sub 21}Si{sub 2}O{sub 5}D{sub 14}. The hydrogen content, its chemical character and the distribution among the three H/D positions was evaluated by {sup 1}H/{sup 2}H MAS NMR spectroscopy for the Si, Ge and Sb compound. The crystal structure exhibits two
A fresnoite-structure-related mixed valent titanium(III/IV) chlorosilicate, Ba{sub 3}Ti{sub 2}Si{sub 4}O{sub 14}Cl: A flux crystal growth route to Ti(III) containing oxides

Energy Technology Data Exchange (ETDEWEB)

Abeysinghe, Dileka; Smith, Mark D.; Loye, Hans-Conrad zur, E-mail: zurloye@mailbox.sc.edu

2017-06-15

Single crystals of mixed valent barium titanium(III/IV) chlorosilicate, Ba{sub 3}Ti{sub 2}Si{sub 4}O{sub 14}Cl{sub 0.91}O{sub 0.09}, were grown in a high temperature molten chloride flux involving an in situ reduction step. The fresnoite structure related Ba{sub 3}Ti{sub 2}Si{sub 4}O{sub 14}Cl{sub 0.91}O{sub 0.09} crystallizes in the tetragonal space group P4/mbm with lattice parameters of a=8.6717(2) Å, c=18.6492(5) Å. The title compound exhibits a 3D structure consisting of 2D layers of fused Ti{sub 2}O{sub 9} and Si{sub 4}O{sub 12} groups and 2D layers of fused Ti{sub 2}O{sub 9}Cl{sub 2} and Si{sub 2}O{sub 7} groups that are linked via barium atoms. The in situ reduction of Ti(IV) to Ti(III) is achieved via the addition of metallic Mg to the flux to function as the reducing agent. The temperature dependence of the magnetic susceptibility shows simple paramagnetism above 100 K. There is a discontinuity in the susceptibility data below 100 K, which might be due to a structural change that takes place resulting in charge ordering. - Graphical abstract: The fresnoite structure related novel reduced barium titanium chlorosilicate, Ba{sub 3}Ti{sub 2}Si{sub 4}O{sub 14}Cl{sub 0.91}O{sub 0.09}, were synthesized via flux method. An in situ reduction of Ti(IV) to Ti(III) achieved using Mg metal. The 3D structure consists 2D layers of fused Ti{sub 2}O{sub 9} and Si{sub 4}O{sub 12} and 2D layers of fused Ti{sub 2}O{sub 9}Cl{sub 2} and Si{sub 2}O{sub 7} connected via barium atoms. Compound shows simple paramagnetism above 100 K. - Highlights: • The fresnoite related Ba{sub 3}Ti{sub 2}Si{sub 4}O{sub 14}Cl{sub 0.91}O{sub 0.09} were grown via molten flux method. • The in situ reduction of Ti(IV) to Ti(III) is achieved using metallic Mg. • 2D layers of Ti{sub 2}O{sub 9} and Si{sub 4}O{sub 12} and Ti{sub 2}O{sub 9}Cl{sub 2} and Si{sub 2}O{sub 7} connect via Ba atoms. • The magnetic susceptibility shows simple paramagnetism above 100 K.
Facile synthesis and electrical switching properties of V{sub 2}O{sub 3} powders

Energy Technology Data Exchange (ETDEWEB)

Ji, Haining; Liu, Dongqing, E-mail: dongqingliu@ymail.com; Cheng, Haifeng; Yang, Lixiang; Zhang, Chaoyang; Zheng, Wenwei

2017-03-15

Highlights: • Single crystal uniform V{sub 2}O{sub 3} powders have been synthesized without additional surfactant. • Powders were obtained in only 6 h. • Powders exhibit reversible phase transition properties. • Powders have excellent electrical switching properties with resistance changes as large as 10{sup 4}. - Abstract: V{sub 2}O{sub 3} powders were synthesized with mercaptoacetic acid (C{sub 2}H{sub 4}O{sub 2}S) as reducing agent and stabilizer via a facile hydrothermal approach. The crystalline structure, surface morphology, valence state of the derived V{sub 2}O{sub 3} powders were characterized via X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy. It was found that the ratio and reaction time played a duel role in the formation and morphology of the V{sub 2}O{sub 3} powders. The metal-insulator transition properties of V{sub 2}O{sub 3} powders were studied by the differential scanning calorimetry curve and variable temperature Raman spectra. The change in electrical resistance due to the metal-insulator transition was measured from 80 to 240 K using physical property measurement system. The results showed V{sub 2}O{sub 3} samples had excellent electrical switching properties with resistance changes as large as 10{sup 4}. This simple and fast synthesis approach makes the V{sub 2}O{sub 3} powders easily accessible for exploring their fundamental properties and potential applications in novel electronic devices.
Luminescence, scintillation, and energy transfer in SiO{sub 2}-Al{sub 2}O{sub 3}-B{sub 2}O{sub 3}-Gd{sub 2}O{sub 3}:Ce{sup 3+},Pr{sup 3+} glasses

Energy Technology Data Exchange (ETDEWEB)

Lertloypanyachai, Prapon; Chewpraditkul, Weerapong; Pattanaboonmee, Nakarin [Department of Physics, King Mongkut' s University of Technology Thonburi, Bangkok (Thailand); Chen, Danping [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai (China); Babin, Vladimir; Beitlerova, Alena; Nikl, Martin [Institute of Physics, AS CR, Prague (Czech Republic)

2017-09-15

Ce{sup 3+},Pr{sup 3+}-codoped SiO{sub 2}-Al{sub 2}O{sub 3}-B{sub 2}O{sub 3}-Gd{sub 2}O{sub 3} glasses (SABG:Ce,Pr) were prepared by melt quenching under a CO reducing atmosphere. Luminescence properties were investigated under UV and X-ray excitations. A dominant emission band at 430 nm belonging to the Ce{sup 3+}:5d{sub 1} → 4f transition was observed in the photo- and radio-luminescence spectra. The energy transfer occurs from this Ce{sup 3+} band toward the {sup 3}P{sub J} levels of Pr{sup 3+} with an efficiency of up to 24%, followed by the reduction of integrated luminescence intensity with an increasing Pr{sup 3+} concentration. This result is attributed to the increase in the reabsorption of Ce{sup 3+} luminescence and the non-radiative energy transfer toward the {sup 3}P{sub J} levels of Pr{sup 3+}. The cross-relaxation process within the Pr{sup 3+} pairs can further diminish the total luminescence yield at high Pr{sup 3+} concentrations. The integral scintillation efficiency and light yield measurements were carried out and compared to the reference Bi{sub 4}Ge{sub 3}O{sub 12} (BGO) crystal. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Evidence for a universal pathway of abscisic acid biosynthesis in higher plants from sup 18 O incorporation patterns

Energy Technology Data Exchange (ETDEWEB)

Zeevaart, J.A.D.; Heath, T.G.; Gage, D.A. (Michigan State University, East Lansing (USA))

1989-12-01

Previous labeling studies of abscisic acid (ABA) with {sup 18}O{sub 2} have been mainly conducted with water-stressed leaves. In this study, {sup 18}O incorporation into ABA of stressed leaves of various species was compared with {sup 18}O labeling of ABA of turgid leaves and of fruit tissue in different stages of ripening. In stressed leaves of all six species investigated, avocado (Persea americana), barley (Hordeum vulgare), bean (Phaseolus vulgaris), cocklebur (Xanthium strumarium), spinach (Spinacia oleracea), and tobacco (Nicotiana tabacum), {sup 18}O was most abundant in the carboxyl group, whereas incorporation of a second and third {sup 18}O in the oxygen atoms on the ring of ABA was much less prominent after 24 h in {sup 18}O{sub 2}. ABA from turgid bean leaves showed significant {sup 18}O incorporation, again with highest {sup 18}O enrichment in the carboxyl group. On the basis of {sup 18}O-labeling patterns observed in ABA from different tissues it is concluded that, despite variations in precusor pool sizes and intermediate turnover rates, there is a universal pathway of ABA biosynthesis in higher plants which involves cleavage of a larger precursor molecule, presumably an oxygenated carotenoid.
Performance improvement of charge-trap memory by using a stacked Zr{sub 0.46}Si{sub 0.54}O{sub 2}/Al{sub 2}O{sub 3} charge-trapping layer

Energy Technology Data Exchange (ETDEWEB)

Tang, Zhenjie; Hu, Dan; Zhang, Xiwei; Zhao, Yage [College of Physics and Electronic Engineering, Anyang Normal University, Anyang 455000 (China); Li, Rong [School of Mathematics and Statistics, Anyang Normal University, Anyang 455000 (China)

2016-11-15

The postdeposition annealing (PDA)-treated charge-trap flash memory capacitor with stacked Zr{sub 0.46}Si{sub 0.54}O{sub 2}/Al{sub 2}O{sub 3} charge-trapping layer flanked by a SiO{sub 2} tunneling oxide and an Al{sub 2}O{sub 3} blocking oxide was fabricated and investigated. It is observed that the memory capacitor exhibits prominent memory characteristics with large memory windows 12.8 V in a ±10 V gate sweeping voltage range, faster program/erase speed, and good data-retention characteristics even at 125 C compared to a single charge-trapping layer (Zr{sub 0.46}Si{sub 0.54}O{sub 2}, Zr{sub 0.79}Si{sub 0.21}O{sub 2}, and Zr{sub 0.46}Al{sub 1.08}O{sub 2.54}). The quantum wells and introduced interfacial traps of the stacked trapping layer regulate the storage and loss behavior of charges, and jointly contribute to the improved memory characteristics. Hence, the memory capacitor with a stacked trapping layer is a promising candidate in future nonvolatile charge-trap memory device design and application. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Photocatalytic performance of nano-photocatalyst from TiO{sub 2} and Fe{sub 2}O{sub 3} by mechanochemical synthesis

Energy Technology Data Exchange (ETDEWEB)

Ghorai, Tanmay K., E-mail: tanmay_ghorai@yahoo.co.in [Department of Chemistry, West Bengal State University, Barasat, North 24 Pgs, Kolkata 700126 (India); Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur 721302 (India); Chakraborty, Mukut [Department of Chemistry, West Bengal State University, Barasat, North 24 Pgs, Kolkata 700126 (India); Pramanik, Panchanan [Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur 721302 (India)

2011-08-11

solution cannot be prepared by conventional co-precipitation technique. A preliminary investigation of photocatalytic activity of mixed oxide (TiO{sub 2}/Fe{sub 2}O{sub 3}) on photo-oxidation of different organic dyes like Rhodamine B (RB), Methyl orange (MO), Thymol blue (TB) and Bromocresol green (BG) under visible light (300-W Xe lamp; {lambda} > 420 nm) showed that TiO{sub 2} having 5 mol% of Fe{sub 2}O{sub 3} (YFT1) is 3-5 times higher photoactive than that of P25 TiO{sub 2}. The XRD result did not show the peaks assigned to the Fe components (for example Fe{sub 2}O{sub 3}, Fe{sub 3}O{sub 4}, FeO{sub 3}, and Fe metal) on the external surface of the anatase structure in the Fe{sub 2}O{sub 3}/TiO{sub 2} attained through mechanochemical treatment. This meant that Fe components were well incorporated into the TiO{sub 2} anatase structure. The average crystallite size and particle size of YFT1 were found to be 12 nm and 30 {+-} 5 nm respectively measured from XRD and TEM conforming to nanodimensions. Together with the Fe component, they absorbed wavelength of above 387 nm. The band slightly shifted to the right without tail broadness, which was the UV absorption of Fe oxide in the Fe{sub 2}O{sub 3}/TiO{sub 2} particle attained through mechanochemical method. This meant that Fe components were well inserted into the framework of the TiO{sub 2} anatase structure. EPR and magnetic susceptibility show that Fe{sup 3+} is in low spin state corresponding to {mu}{sub B} = 1.8 BM. The temperature variation of {mu}{sub B} shows that Fe{sup 3+} is well separated from each other and does not have any antiferromagnetic or ferromagnetic interaction. The evidence of Fe{sup 3+} in TiO{sub 2}/Fe{sub 2}O{sub 3} alloy is also proved by a new method that is redox titration which is again support by the XPS spectrum.
Phase separation, crystallization and polyamorphism in the Y{sub 2}O{sub 3}-Al{sub 2}O{sub 3} system

Energy Technology Data Exchange (ETDEWEB)

Skinner, Lawrie B; Barnes, Adrian C [H H Wills Physics Laboratory, Royal Fort, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Salmon, Philip S [Department of Physics, University of Bath, Bath BA2 7AY (United Kingdom); Crichton, Wilson A [European Synchrotron Radiation Facility, 6 rue Jules Horowitz, BP 220, Grenoble Cedex, F-38043 (France)], E-mail: a.c.barnes@bristol.ac.uk

2008-05-21

A detailed study of glass formation from aerodynamically levitated liquids in the (Y{sub 2}O{sub 3}){sub x}(Al{sub 2}O{sub 3}){sub 1-x} system for the composition range 0.21{<=}x{<=}0.41 was undertaken by using pyrometric, optical imaging and x-ray diffraction methods. Homogeneous and clear single-phase glasses were produced over the composition range 0.27{<=}x{<=}0.33. For Y{sub 2}O{sub 3}-rich compositions (0.33{<=}x{<=}0.375), cloudy materials were produced which contain inclusions of crystalline yttrium aluminium garnet (YAG) of diameter up to 40 {mu}m in a glassy matrix. For Y{sub 2}O{sub 3}-poor compositions around x = 0.24, cloudy materials were also produced, but it was not possible to deduce whether this resulted from (i) sub-micron inclusions of a nano-crystalline or glassy material in a glassy matrix or (ii) a glass formed by spinodal decomposition. For x = 0.21, however, the sample cloudiness results from crystallization into at least two phases comprising yttrium aluminium perovskite and alumina. The associated pyrometric cooling curve shows slow recalescence events with a continuous and slow evolution of excess heat which contrasts with the sharp recalescence events observed for the crystallization of YAG at compositions near x = 0.375. The materials that are the most likely candidates for demonstrating homogeneous nucleation of a second liquid phase occur around x = 0.25, which corresponds to the limit for formation of a continuous random network of corner-shared AlO{sub 4} tetrahedra.
Photoelectric characteristics of metal-Ga{sub 2}O{sub 3}-GaAs structures

Energy Technology Data Exchange (ETDEWEB)

Kalygina, V. M., E-mail: Kalygina@ngs.ru; Vishnikina, V. V.; Petrova, Yu. S.; Prudaev, I. A.; Yaskevich, T. M. [National Research Tomsk State University (Russian Federation)

2015-03-15

We investigate the effect of thermal annealing in argon and of oxygen plasma processing on the photoelectric properties of GaAs-Ga{sub 2}O{sub 3}-Me structures. Gallium-oxide films are fabricated by photostimulated electrochemical oxidation of epitaxial gallium-arsenide layers with n-type conductivity. The as-deposited films were amorphous, but their processing in oxygen plasma led to the nucleation of β-Ga{sub 2}O{sub 3} crystallites. The unannealed films are nontransparent in the visible and ultraviolet (UV) ranges and there is no photocurrent in structures based on them. After annealing at 900°C for 30 min, the gallium-oxide films contain only β-Ga{sub 2}O{sub 3} crystallites and become transparent. Under illumination of the Ga{sub 2}O{sub 3}-GaAs structures with visible light, the photocurrent appears. This effect can be attributed to radiation absorption in GaAs. The photocurrent and its voltage dependence are determined by the time of exposure to the oxygen plasma. In the UV range, the sensitivity of the structures increases with decreasing radiation wavelength, starting at λ ≤ 230 nm. This is due to absorption in the Ga{sub 2}O{sub 3} film. Reduction in the structure sensitivity with an increase in the time of exposure to oxygen plasma can be caused by the incorporation of defects both at the Ga{sub 2}O{sub 3}-GaAs interface and in the Ga{sub 2}O{sub 3} film.
Effect of H{sub 2}O{sub 2} on the corrosion behavior of 304L stainless steel

Energy Technology Data Exchange (ETDEWEB)

Song, Taek Ho

1994-02-15

In connection with the safe storage of high level nuclear waste, effect of H{sub 2}O{sub 2} on the corrosion behavior of 304L stainless steel was examined. Open circuit potentials and polarization curves were measured with and without H{sub 2}O{sub 2}. The experimental results show that H{sub 2}O{sub 2} increased corrosion potential and decreased pitting potential. The passive range, therefore, decreased as H{sub 2}O{sub 2} concentration increased, indicating that pitting resistance was decreased by the existence of H{sub 2}O{sub 2} in the electrolyte. These effects of H{sub 2}O{sub 2} on corrosion of 304L stainless steel are considered to be similar to those of γ-irradiation. To compare the effects of H{sub 2}O{sub 2} with those of O{sub 2}, cathodic and anodic polarization curves were made in three types of electrolyte such as aerated, deaerated, and stirred electrolyte. The experimental results show that the effects of H{sub 2}O{sub 2} on the corrosion behavior were very similar to those of O{sub 2} such as increase of corrosion potential, decrease of pitting resistance, and increase of repassivation potential. Further, H{sub 2}O{sub 2} played much greater role in controlling cathodic reaction rate in neutral water environment. In acid and alkaline media, potential shifts by H{sub 2}O{sub 2} were restricted by the large current density of proton reduction and by the le Chatelier's principle respectively.
Interfacial effects of the Cu{sub 2}O nano-dots decorated Co{sub 3}O{sub 4} nanorods array and its photocatalytic activity for cleaving organic molecules

Energy Technology Data Exchange (ETDEWEB)

Qiu, X.P. [Key Laboratory of Advanced Textile Materials and Manufacturing Technology, Ministry of Education, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Yu, J.S. [Department of Chemistry and Chemical Engineering, University of New Haven, 300 Boston Post Road, West Haven, CT 06516 (United States); Xu, H.M.; Chen, W.X.; Hu, W. [Key Laboratory of Advanced Textile Materials and Manufacturing Technology, Ministry of Education, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Chen, G.L., E-mail: glchen@zstu.edu.cn [Key Laboratory of Advanced Textile Materials and Manufacturing Technology, Ministry of Education, Zhejiang Sci-Tech University, Hangzhou 310018 (China)

2016-09-30

Highlights: • Co{sub 3}O{sub 4} rods were grown on plasma treated Ti foil. • Cu{sub 2}O QDs were uniformly distributed on the surface of nanorods. • Ti/Co{sub 3}O{sub 4}/Cu{sub 2}O exhibited visible light photocatalytic activity with KHSO{sub 5}. • Degradation mechanism was supported by ESR technique and radical scavenger tests. • The heterojunction was highly stable even after recycling many times. - Abstract: A heterogeneous nanocomposite catalyst constructed by the Co{sub 3}O{sub 4} nanorods decorated with the Cu{sub 2}O quantum dots (QDs) were successfully synthesized via a simple hydrothermal method followed by an oxidation-reduction processing. The fabricated Cu{sub 2}O/Co{sub 3}O{sub 4} nanocomposite was characterized by the SEM, TEM, XPS, XRD, UV–vis and PL, and the (2 2 0) and (3 1 1) facets of the Co{sub 3}O{sub 4} were exposed. Compared with the original Co{sub 3}O{sub 4} nanorods with an average diameter of 350 nm, a substantial decrease in the band gap was observed after doping the nanorods with the Cu{sub 2}O QDs (average diameter of 5 nm). Such a dramatic decrease in the band gap indicated a significant enhancement of the photocatalytic activities under visible light. The methylene blue (MB) dye and the phenol were used as model organic pollutants, and the Cu{sub 2}O/Co{sub 3}O{sub 4} nanocomposite catalyst exhibited both high catalytic activity and good recycling stability. The catalytic activities of the Cu{sub 2}O/Co{sub 3}O{sub 4}/potassium monopersulfate triple salt (PMS) system for cleaving the MB and the phenol were dependent on the dosages of the Cu{sub 2}O QDs, and the calculated degradation rates achieved by 7.0 wt% Cu{sub 2}O/Co{sub 3}O{sub 4} nanocomposite catalyst were about 11.3 and 1.8 times than that of the pristine Co{sub 3}O{sub 4} nanorod catalyst for the MB and the phenol, respectively. The reactive species of ·O{sub 2}{sup −} and the holes were determined to be the main active species for the phenol photocatalytic
Atomic layer deposition of Al{sub 2}O{sub 3} and Al{sub 2}O{sub 3}/TiO{sub 2} barrier coatings to reduce the water vapour permeability of polyetheretherketone

Energy Technology Data Exchange (ETDEWEB)

Ahmadzada, Tamkin, E-mail: tahm4852@uni.sydney.edu.au [School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney, NSW 2006 (Australia); McKenzie, David R.; James, Natalie L.; Yin, Yongbai [School of Physics, University of Sydney, NSW 2006 (Australia); Li, Qing [School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney, NSW 2006 (Australia)

2015-09-30

We demonstrate significantly enhanced barrier properties of polyetheretherketone (PEEK) against water vapour penetration by depositing Al{sub 2}O{sub 3} or Al{sub 2}O{sub 3}/TiO{sub 2} nanofilms grown by atomic layer deposition (ALD). Nanoindentation analysis revealed good adhesion strength of a bilayer Al{sub 2}O{sub 3}/TiO{sub 2} coating to PEEK, while the single layer Al{sub 2}O{sub 3} coating displayed flaking and delamination. We identified three critical design parameters for achieving the optimum barrier properties of ALD Al{sub 2}O{sub 3}/TiO{sub 2} coatings on PEEK. These are a minimum total thickness dependent on the required water vapour transmission rate, the use of an Al{sub 2}O{sub 3}/TiO{sub 2} bilayer coating and the application of the coating to both sides of the PEEK film. Using these design parameters, we achieved a reduction in moisture permeability of PEEK of over two orders of magnitude while maintaining good adhesion strength of the polymer–thin film system. - Highlights: • Atomic layer deposition of Al{sub 2}O{sub 3}/TiO{sub 2} coatings reduced water vapour permeability. • Bilayer coatings reduced the permeability more than single layer coatings. • Bilayer coatings displayed higher adhesion strength than the single layer coatings. • Double-sided coatings performed better than single-sided coatings. • Correlation was found between total thickness and reduced water vapour permeability.
Hyperfine interaction of {sup 25}Al in {alpha}-Al{sub 2}O{sub 3} and its quadrupole moment

Energy Technology Data Exchange (ETDEWEB)

Matsuta, K., E-mail: matsuta@vg.phys.sci.osaka-u.ac.jp; Mihara, M. [Osaka University, Department of Physics (Japan); Nagatomo, T. [RIKEN (Japan); Matsumiya, R. [Osaka University, Department of Physics (Japan); Momota, S. [Kochi University of Technology (Japan); Ohtsubo, T. [Niigata University, Department of Physics (Japan); Izumikawa, T. [Niigata University, Radioisotope Center (Japan); Hirano, H.; Takahashi, S. [Niigata University, Department of Physics (Japan); Nishimura, D.; Komurasaki, J. [Osaka University, Department of Physics (Japan); Kitagawa, A.; Kanazawa, M.; Torikoshi, M.; Sato, S. [National Institute of Radiological Sciences (Japan); Fukuda, M. [Osaka University, Department of Physics (Japan); Minamisono, T. [Fukui University of Technology (Japan); Sumikama, T. [Tokyo University of Science (Japan); Tanaka, K.; Takechi, M. [RIKEN (Japan)

2007-11-15

The electric quadrupole (Q) moment of short-lived nucleus {sup 25}Al (I{sup {pi}} = 5/2{sup +}, T{sub 1/2} = 7.18 s) has been measured for the first time, by means of the {beta}-NQR technique. The spin polarization of {sup 25}Al was produced in heavy ion collisions and was kept in a {alpha}-Al{sub 2}O{sub 3} single crystal for as long as 2 s and the quadrupole coupling frequency was obtained as vertical bar eqQ / h({sup 25}Al in Al{sub 2}O{sub 3}) vertical bar = (4.05 {+-}0.30) MHz. From the result, the Q moment was determined as |Q({sup 25}Al)| = (240 {+-}20) mb. The present Q moment is larger by 30% than the shell model value of 184 mb, calculated by OXBASH code, which may show additional deformation of the nucleus.
Investigation of fluorine adsorption on nitrogen doped MgAl{sub 2}O{sub 4} surface by first-principles

Energy Technology Data Exchange (ETDEWEB)

Lv, Xiaojun; Xu, Zhenming [School of Metallurgy and Environment, Central South University, Changsha 410083 (China); Li, Jie, E-mail: 15216105346@163.com [School of Metallurgy and Environment, Central South University, Changsha 410083 (China); Chen, Jiangan [Faculty of Resource and Environmental Engineering, Jiangxi University of Science and Technology, Ganzhou 341000 (China); Liu, Qingsheng [Faculty of Metallurgical and Chemical Engineering, Jiangxi University of Science and Technology, Ganzhou 341000 (China)

2016-07-15

Graphical abstract: First-principles calculations indicate that MgAl{sub 2}O{sub 4} surface is fluorine-loving, but hydrophobic. N doped MgAl{sub 2}O{sub 4} (100) surface structure shows the highest fluorine adsorption performance and fluorine atom is more preferentially adsorbed on the Mg-Al bridge site. The fluorine adsorption intensity follow this order: N doped MgAl{sub 2}O{sub 4} (100) > Al{sub 2}O{sub 3} (0001) > MgAl{sub 2}O{sub 4} (100) > MgO (100). N doped MgAl{sub 2}O{sub 4} is a promising candidate for fluorine removal. - Highlights: • MgAl{sub 2}O{sub 4} surface is fluorine-loving, not hydrophilic. • Fluorine preferentially adsorbs on the Mg-Al bridge site. • Adsorption intensity follow this order: N doped MgAl{sub 2}O{sub 4} > Al{sub 2}O{sub 3} > MgAl{sub 2}O{sub 4} > MgO. • Excellent adsorption performance attributes to electron compensation of N atom. • Nitrogen doped MgAl{sub 2}O{sub 4} is a promising candidate for fluorine removal. - Abstract: The nature of fluorine adsorption on pure and N doped MgAl{sub 2}O{sub 4} surface has been investigated by first-principles calculations based on the density functional theory. Calculated results indicate that MgAl{sub 2}O{sub 4} surface is fluorine-loving, not hydrophilic. Nitrogen doped MgAl{sub 2}O{sub 4} (100) surface shows the highest fluorine adsorption performance and fluorine atom preferentially adsorbs on the Mg-Al bridge site. The fluorine adsorption intensity follow this order: Nitrogen doped MgAl{sub 2}O{sub 4} (100) > Al{sub 2}O{sub 3} (0001) > MgAl{sub 2}O{sub 4} (100) > MgO (100). In-depth PDOS analysis suggested that 2p orbitals of F atom strongly hybridized with 3s- and 3p-orbitals of Al atom contribute to its high adsorption intensity. According to the analysis of Hirshfeld charge, the excellent fluorine adsorption performance of nitrogen doped MgAl{sub 2}O{sub 4} attributes to the electron compensation effect of nitrogen atom and strong electrostatic interactions. All these

Luminescence of Cr{sup 3+} ions in ZnAl{sub 2}O{sub 4} and MgAl{sub 2}O{sub 4} spinels: correlation between experimental spectroscopic studies and crystal field calculations

Energy Technology Data Exchange (ETDEWEB)

Brik, M.G., E-mail: mikhail.brik@ut.ee [College of Sciences, Chongqing University of Posts and Telecommunications, Chongqing 400065 (China); Institute of Physics, University of Tartu, W. Ostwald Str. 1, Tartu 50411 (Estonia); Institute of Physics, Jan Dlugosz University, Al. Armii Krajowej 13/15, Czestochowa PL-42200 (Poland); Papan, J.; Jovanović, D.J. [University of Belgrade, Vinča Institute of Nuclear Sciences, P.O. Box 522, Belgrade 11001 (Serbia); Dramićanin, M.D., E-mail: dramican@vinca.rs [University of Belgrade, Vinča Institute of Nuclear Sciences, P.O. Box 522, Belgrade 11001 (Serbia)

2016-09-15

Details of preparation, spectroscopic and structural studies along with crystal field calculations for two Cr{sup 3+} doped spinels MgAl{sub 2}O{sub 4} and ZnAl{sub 2}O{sub 4} are given in the present paper. Both compounds show efficient red emission at about 685 nm, which is due to the {sup 2}E{sub g} → {sup 4}A{sub 2g} spin-forbidden transition of Cr{sup 3+} ions located at the sites with D{sub 3d} local symmetry. Analysis of structure of the CrO{sub 6} clusters was performed; comparison of the crystal field effects in both compounds revealed that the low-symmetry splitting of the orbital triplet states is more pronounced in ZnAl{sub 2}O{sub 4}. Both compounds show potential for applications as red-emitting phosphors. - Highlights: • Cr{sup 3+}-doped MgAl{sub 2}O{sub 4} and ZnAl{sub 2}O{sub 4} spinels were synthesized. • Excitation/emission spectra were recorded and analyzed. • Symmetry properties of the Cr-sites were analyzed. • Cr{sup 3+} energy levels in trigonal crystal field were calculated. • Cr{sup 3+}-doped MgAl{sub 2}O{sub 4} and ZnAl{sub 2}O{sub 4} spinels can be used as red phosphors.
Magnetism and thermal induced characteristics of Fe{sub 2}O{sub 3} content bioceramics

Energy Technology Data Exchange (ETDEWEB)

Wu, Chun-Shiang; Hsi, Chi-Shiung [Department of Materials Science and Engineering, National United University, Miaoli 36003, Taiwan (China); Hsu, Fang-Chi, E-mail: fangchi@nuu.edu.tw [Department of Materials Science and Engineering, National United University, Miaoli 36003, Taiwan (China); Wang, Moo-Chin [Department of Fragrance and Cosmetics, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China); Chen, Yung-Sheng [Department of Materials Science and Engineering, I-Shou University, Kaohsiung 803, Taiwan (China)

2012-11-15

Magnetic properties of Li{sub 2}O-MnO{sub 2}-CaO-P{sub 2}O{sub 5}-SiO{sub 2} (LMCPS) glasses doped with various amounts of Fe{sub 2}O{sub 3} were investigated. There is a dramatic change in the magnetic property of pristine LMCPS after the addition of Fe{sub 2}O{sub 3} and crystallized at 850 Degree-Sign C for 4 h. Both the electron paramagnetic resonance and magnetic susceptibility measurements showed that the glass ceramic with 4 at% Fe{sub 2}O{sub 3} exhibited the coexistence of superparamagnetism and ferromagnetism at room temperature. When the Fe{sub 2}O{sub 3} content was higher than 8 at%, the LMCPS glasses showed ferromagnetism behavior. The complex magnetic behavior is due to the distribution of (Li, Mn)ferrite particle sizes driven by the Fe{sub 2}O{sub 3} content. The thermal induced hysteresis loss of the crystallized LMCPS glass ceramics was characterized under an alternating magnetic field. The energy dissipations of the crystallized LMCPS glass ceramics were determined by the concentration and Mn/Fe ratios of Li(Mn, Fe)ferrite phase formed in the glass ceramics. - Highlights: Black-Right-Pointing-Pointer Presence of Fe{sub 2}O{sub 3} in LMCPS glass ceramic promotes the growth of (Li, Mn)ferrite. Black-Right-Pointing-Pointer The amount of Fe{sub 2}O{sub 3} determines the size of (Li,Mn)ferrite particles. Black-Right-Pointing-Pointer Room temperature superparamagnetism was obtained at 4 at% of Fe{sub 2}O{sub 3} addition. Black-Right-Pointing-Pointer In addition, Li(Mn, Fe)ferrite phase contributes to the magnetic energy loss. Black-Right-Pointing-Pointer The largest energy loss is the trade-off between the ferrite content and Mn/Fe ratio.
PEG/CaFe{sub 2}O{sub 4} nanocomposite: Structural, morphological, magnetic and thermal analyses

Energy Technology Data Exchange (ETDEWEB)

Khanna, Lavanya, E-mail: lavanshya@yahoo.co.in; Verma, Narendra K., E-mail: nkverma@thapar.edu

2013-10-15

The coating of Polyethylene Glycol (PEG) on calcium ferrite (CaFe{sub 2}O{sub 4}) nanoparticles has been reported in the present study. The X-ray diffraction pattern revealed the formation of orthorhombic structure of bare CaFe{sub 2}O{sub 4} nanoparticles, which was also retained after the PEG coating, along with additional characteristic peaks of PEG at 19° and 23°. The rings of CaFe{sub 2}O{sub 4} nanoparticles were identified by the selected area electron diffraction pattern. The characteristic bands of PEG as observed in its Fourier transform infrared spectrum were also present in PEG coated CaFe{sub 2}O{sub 4} nanoparticles, hence confirming its presence. In the thermal gravimetric studies, the complete thermal decomposition of PEG occurred in a one step process, but in case of PEG coated CaFe{sub 2}O{sub 4} nanoparticles, the decomposition took place at a higher temperature owing to the formation of covalent bonds of PEG with CaFe{sub 2}O{sub 4} nanoparticles. The presence of PEG on CaFe{sub 2}O{sub 4} nanoparticles, spherical formation of PEG coated CaFe{sub 2}O{sub 4} nanoparticles and reduced agglomeration in the CaFe{sub 2}O{sub 4} nanoparticles were revealed by high resolution transmission electron microscope, transmission electron microscope and scanning electron microscope studies, respectively. In vibrating sample magnetometer analysis, both bare as well as coated CaFe{sub 2}O{sub 4} nanoparticles exhibited superparamagnetic behavior. However, a drop in the magnetic saturation value was observed from 36.76 emu/g for CaFe{sub 2}O{sub 4} nanoparticles to 6.74 emu/g for PEG coated CaFe{sub 2}O{sub 4} nanoparticles, due to the formation of magnetically dead layer of PEG. In ZFC and FC analyses, superparamagnetic behavior with blocking temperature for bare and coated nanoparticles has been observed at ∼40 K and ∼60 K, respectively. The increase in the blocking temperature is attributed to the increase in the particle size after PEG coating.
On the dimorphism of Pr{sub 6}Mo{sub 10}O{sub 39}

Energy Technology Data Exchange (ETDEWEB)

Rudolph, Daniel; Laufer, Sonja; Hartenbach, Ingo [Stuttgart Univ. (Germany). Inst. for Inorganic Chemistry

2017-07-01

Attempts to synthesize Pr{sub 4}Mo{sub 7}O{sub 27} using Pr, Pr{sub 6}O{sub 11} and MoO{sub 3} in a molar ratio of 8:6:77 led to a main product of scheelite-type Pr{sub 0.667}[MoO{sub 4}] and few single crystals of the triclinic A-type Pr{sub 6}Mo{sub 10}O{sub 39}. The latter crystallizes in space group P anti 1 (a=945.25(1), b=1058.49(2), c=1815.16(3) pm; α=104.149(1), β=95.220(1), γ=102.617(1) , Z=2). Its crystal structure comprises six crystallographically independent Pr{sup 3+} cations, eight tetrahedral [MoO{sub 4}]{sup 2-} units, and one [Mo{sub 2}O{sub 7}]{sup 2-} entity. The cations display coordination numbers of seven (1 x) and eight (5 x), while the [MoO{sub 4}]{sup 2-} tetrahedra are surrounded by five Pr{sup 3+} cations each. The [Mo{sub 2}O{sub 7}]{sup 2-} anions exhibit a coordination environment of seven Pr{sup 3+} cations. The attempt to synthesize PrF[MoO{sub 4}] using PrOF (from in situ thermal decomposition of PrF[CO{sub 3}]) as reagent did not lead to the desired product but to monoclinic B-type Pr{sub 6}Mo{sub 10}O{sub 39}. This slightly less dense modification compared to its triclinic analogue crystallizes in space group C2/c (a=1247.93(3), b=1989.68(6), c=1392.52 (4) pm, β=100.505(2) , Z=4) with three crystallographically independent Pr{sup 3+} cations, four [MoO{sub 4}]{sup 2-} tetrahedra, and again one [Mo{sub 2}O{sub 7}]{sup 2-} unit in the crystal structure. Thus, both Pr{sub 6}Mo{sub 10}O{sub 39} modifications are better described with the structured formula Pr{sub 6}[MoO{sub 4}]{sub 8}[Mo{sub 2}O{sub 7}]. The coordination numbers around the Pr{sup 3+} cations are seven (1 x) and eight (2 x) while all four [MoO{sub 4}]{sup 2-} anions are again surrounded by five Pr{sup 3+} cations each. Six of the latter represent the coordination environment around the [Mo{sub 2}O{sub 7}]{sup 2-} entities. Besides the thorough comparison of the crystal structures single crystal Raman spectra were recorded for both Pr{sub 6}Mo{sub 10}O{sub 39
Chemical synthesis of Fe{sub 2}O{sub 3} thin films for supercapacitor application

Energy Technology Data Exchange (ETDEWEB)

Kulal, P.M.; Dubal, D.P.; Lokhande, C.D. [Holography and Material Research Laboratory, Department of Physics, Shivaji University, Kolhapur 416004, M.S. (India); Fulari, V.J., E-mail: vijayfulari@gmail.com [Holography and Material Research Laboratory, Department of Physics, Shivaji University, Kolhapur 416004, M.S. (India)

2011-02-03

Research highlights: > Simple chemical synthesis of Fe{sub 2}O{sub 3}. > Formation of amorphous and hydrous Fe{sub 2}O{sub 3}. > Potential candidate for supercapacitors. - Abstract: Fe{sub 2}O{sub 3} thin films have been prepared by novel chemical successive ionic layer adsorption and reaction (SILAR) method. Further these films were characterized for their structural, morphological and optical properties by means of X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectrum, scanning electron microscopy (SEM), wettability test and optical absorption studies. The XRD pattern showed that the Fe{sub 2}O{sub 3} films exhibit amorphous in nature. Formation of iron oxide compound was confirmed from FTIR studies. The optical absorption showed existence of direct optical band gap of energy 2.2 eV. Fe{sub 2}O{sub 3} film surface showed superhydrophilic nature with water contact angle less than 10{sup o}. The supercapacitive properties of Fe{sub 2}O{sub 3} thin film investigated in 1 M NaOH electrolyte showed supercapacitance of 178 F g{sup -1} at scan rate 5 mV/s.
Novel time-dependent vascular actions of {delta}{sup 9}-tetrahydrocannabinol mediated by peroxisome proliferator-activated receptor gamma

Energy Technology Data Exchange (ETDEWEB)

O' Sullivan, Saoirse E [School of Biomedical Sciences, E Floor, Queen' s Medical Centre, University of Nottingham, Nottingham NG7 2UH (United Kingdom); Tarling, Elizabeth J [School of Biomedical Sciences, E Floor, Queen' s Medical Centre, University of Nottingham, Nottingham NG7 2UH (United Kingdom); Bennett, Andrew J [School of Biomedical Sciences, E Floor, Queen' s Medical Centre, University of Nottingham, Nottingham NG7 2UH (United Kingdom); Kendall, David A [School of Biomedical Sciences, E Floor, Queen' s Medical Centre, University of Nottingham, Nottingham NG7 2UH (United Kingdom); Randall, Michael D [School of Biomedical Sciences, E Floor, Queen' s Medical Centre, University of Nottingham, Nottingham NG7 2UH (United Kingdom)

2005-11-25

Cannabinoids have widespread effects on the cardiovascular system, only some of which are mediated via G-protein-coupled cell surface receptors. The active ingredient of cannabis, {delta}{sup 9}-tetrahydrocannabinol (THC), causes acute vasorelaxation in various arteries. Here we show for the first time that THC also causes slowly developing vasorelaxation through activation of peroxisome proliferator-activated receptors gamma (PPAR{gamma}). In vitro, THC (10 {mu}M) caused time-dependent vasorelaxation of rat isolated arteries. Time-dependent vasorelaxation to THC was similar to that produced by the PPAR{gamma} agonist rosiglitazone and was inhibited by the PPAR{gamma} antagonist GW9662 (1 {mu}M), but not the cannabinoid CB{sub 1} receptor antagonist AM251 (1 {mu}M). Time-dependent vasorelaxation to THC requires an intact endothelium, nitric oxide, production of hydrogen peroxide, and de novo protein synthesis. In transactivation assays in cultured HEK293 cells, THC-activated PPAR{gamma}, transiently expressed in combination with retinoid X receptor {alpha} and a luciferase reporter gene, in a concentration-dependent manner (100 nM-10 {mu}M). In vitro incubation with THC (1 or 10 {mu}M, 8 days) stimulated adipocyte differentiation in cultured 3T3L1 cells, a well-accepted property of PPAR{gamma} ligands. The present results provide strong evidence that THC is a PPAR{gamma} ligand, stimulation of which causes time-dependent vasorelaxation, implying some of the pleiotropic effects of cannabis may be mediated by nuclear receptors.
Effect of H{sub 2}O{sub 2} on the corrosion behavior of 304L stainless steel

Energy Technology Data Exchange (ETDEWEB)

Song, Taek Hoh; Kim, In Sub [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of); Noh, Sung Kee [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

1995-08-01

In connection with the safe storage of high level nuclear waste, effect of H{sub 2}O{sub 2} on the corrosion behavior of 304L stainless steel was examined. Open circuit potentials and polarization curves were measured with and without H{sub 2}O{sub 2}. The experimental results show that H{sub 2}O{sub 2} increased corrosion potential and decreased pitting potential. The passive range, therefore, decreased as H{sub 2}O{sub 2} concentration increased, indicating that pitting resistance was decreased by the existence of H{sub 2}O{sub 2} in the electrolyte. These effects of H{sub 2}O{sub 2} on corrosion of 304L stainless steel are considered to be similar to those of {gamma}-irradiation. To compare the effects of H{sub 2}O{sub 2} with those of O{sub 2}, cathodic and anodic polarization curves were made in three types of electrolyte such as aerated, deaerated, and stirred electrolyte. The experimental results show that the effects of H{sub 2}O{sub 2} on the corrosion behavior were very similar to those of O{sub 2} such as increase of corrosion potential, decrease of pitting resistance, and increase of repassivation potential. In acid and alkaline media, the corrosion potential shifts by H{sub 2}O{sub 2} were restricted by the large current density of proton reduction and by the le Chatelier`s principle respectively. 13 figs., 1 tabs., 17 refs. (Author).
Domain matching epitaxy of cubic In{sub 2}O{sub 3} on r-plane sapphire

Energy Technology Data Exchange (ETDEWEB)

Vogt, Patrick; Trampert, Achim; Ramsteiner, Manfred; Bierwagen, Oliver [Paul-Drude-Institut fuer Festkoerperelektronik, Hausvogteiplatz 5-7, 10117, Berlin (Germany)

2015-07-15

Undoped, Sn-doped, and Mg-doped In{sub 2}O{sub 3} layers were grown on rhombohedral r-plane sapphire (α-Al{sub 2}O{sub 3} (10.2)) by plasma-assisted molecular beam epitaxy. X-ray diffraction and Raman scattering experiments demonstrated the formation of phase-pure, cubic (110)-oriented In{sub 2}O{sub 3} for Sn- and Mg-concentrations up to 2 x 10{sup 20} and 6 x 10{sup 20} cm{sup -3}, respectively. Scanning electron microscopy images showed facetted domains without any surface-parallel (110) facets. High Mg- or Sn-doping influenced surface morphology and the facet formation. X-ray diffraction Φ-scans indicated the formation of two rotational domains separated by an angle Φ = 86.6 due to the substrate mirror-symmetry around the in-plane-projected Al{sub 2}O{sub 3} c-axis. The in-plane epitaxial relationships to the substrate were determined for both domains. For the first domain it is Al{sub 2}O{sub 3}[01.0] parallel In{sub 2}O{sub 3}[3 anti 3 anti 4]. For the second domain the inplane epitaxial relation is Al{sub 2}O{sub 3}[01.0] parallel In{sub 2}O{sub 3}[3 anti 34]. A low-mismatch coincidence lattice of indium atoms from the film and oxygen atoms from the substrate rationalizes this epitaxial relation by domain-matched epitaxy. Cross-sectional transmission-electron microscopy showed a columnar domain-structure, indicating the vertical growth of the rotational domains after their nucleation. Coincidence structure of In{sub 2}O{sub 3} (110) (In atoms in red) grown on Al{sub 2}O{sub 3} (10.2) (O atoms in blue) showing two rotational domians. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Fabrication of low thermal expansion SiC/ZrW{sub 2}O{sub 8} porous ceramics

Energy Technology Data Exchange (ETDEWEB)

Poowancum, A; Matsumaru, K; Juarez-Ramirez, I; Ishizaki, K [Department of Mechanical Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188 (Japan); Torres-Martinez, L M [Universidad Autonoma de Nuevo Leon, Av. Universidad s/n, San Nicolas de los Garza, NL, C.P. 66451 (Mexico); Fu, Z Y [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, Hubei, 430070 (China); Lee, S W, E-mail: anurat@ishizaki.nagaokaut.ac.jp [Department of Environment Engineering, Sun Moon University, 100, Kalsan-ri, Tangjeong-myeon, Asan, Chungnam 336-708 (Korea, Republic of)

2011-03-15

Low or zero thermal expansion porous ceramics are required for several applications. In this work near zero thermal expansion porous ceramics were fabricated by using SiC and ZrW{sub 2}O{sub 8} as positive and negative thermal expansion materials, respectively, bonded by soda lime glass. The mixture of SiC, ZrW{sub 2}O{sub 8} and soda lime glass was sintered by Pulsed Electric Current Sintering (PECS, or sometimes called Spark Plasma Sintering, SPS) at 700 deg. C. Sintered samples with ZrW{sub 2}O{sub 8} particle size smaller than 25 {mu}m have high thermal expansion coefficient, because ZrW{sub 2}O{sub 8} has the reaction with soda lime glass to form Na{sub 2}ZrW{sub 3}O{sub 12} during sintering process. The reaction between soda lime glass and ZrW{sub 2}O{sub 8} is reduced by increasing particle size of ZrW{sub 2}O{sub 8}. Sintered sample with ZrW{sub 2}O{sub 8} particle size 45-90 {mu}m shows near zero thermal expansion.
Phase relationships in the area of the beta aluminate of the system K{sub 2}O-MgO-AL{sub 2}O{sub 3}; Phasenbeziehungen im Bereich der Beta-Aluminate des Systems K{sub 2}O-MgO-Al{sub 2}O{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Kroon, P de

1996-12-01

The aim of this work was to be able to make statements about the thermodynamic stability of K-{beta}``-Al{sub 2}O{sub 3} in the pseudo-binary system K{sub 2}O-Al{sub 2}O{sub 3} and in the pseudo-ternary system K{sub 2}O-MgO-Al{sub 2}O{sub 3} relative to the adjacent phases of KAlO{sub 2} {alpha}-Al{sub 2}O{sub 3}, MgAl{sub 2}O{sub 4} and K-{beta}-Al{sub 2}O{sub 3}. (orig./MM) [Deutsch] Ziel dieser Arbeit war es, Aussagen ueber die thermodynamische Stabilitaet von K-{beta}``-Al{sub 2}O{sub 3} im pseudobinaeren System K{sub 2}O-Al{sub 2}O{sub 3} und im pseudoternaeren System K{sub 2}O-MgO-Al{sub 2}O{sub 3} relativ zu den benachbarten Phasen KAlO{sub 2}, {alpha}-Al{sub 2}O{sub 3}, MgAl{sub 2}O{sub 4} und K-{beta}-Al{sub 2}O{sub 3} machen zu koennen. (orig./MM)
High-pressure synthesis and single-crystal structure elucidation of the indium oxide-borate In{sub 4}O{sub 2}B{sub 2}O{sub 7}

Energy Technology Data Exchange (ETDEWEB)

Ortner, Teresa S.; Vitzthum, Daniela; Heymann, Gunter; Huppertz, Hubert [Department of General, Inorganic and Theoretical Chemistry, Centre of Chemistry and Biomedicine (CCB), Leopold-Franzens-University Innsbruck (Austria)

2017-12-29

The indium oxide-borate In{sub 4}O{sub 2}B{sub 2}O{sub 7} was synthesized under high-pressure/high-temperature conditions at 12.5 GPa/1420 K using a Walker-type multianvil apparatus. Single-crystal X-ray structure elucidation showed edge-sharing OIn{sub 4} tetrahedra and B{sub 2}O{sub 7} units building up the oxide-borate. It crystallizes with Z = 8 in the monoclinic space group P2{sub 1}/n (no. 14) with a = 1016.54(3), b = 964.55(3), c = 1382.66(4) pm, and β = 109.7(1) . The compound was also characterized by powder X-ray diffraction and vibrational spectroscopy. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Nearest-cell: a fast and easy tool for locating crystal matches in the PDB

International Nuclear Information System (INIS)

Ramraj, V.; Evans, G.; Diprose, J. M.; Esnouf, R. M.

2012-01-01

A fast and easy tool to locate unit-cell matches in the PDB is described. When embarking upon X-ray diffraction data collection from a potentially novel macromolecular crystal form, it can be useful to ascertain whether the measured data reflect a crystal form that is already recorded in the Protein Data Bank and, if so, whether it is part of a large family of related structures. Providing such information to crystallographers conveniently and quickly, as soon as the first images have been recorded and the unit cell characterized at an X-ray beamline, has the potential to save time and effort as well as pointing to possible search models for molecular replacement. Given an input unit cell, and optionally a space group, Nearest-cell rapidly scans the Protein Data Bank and retrieves near-matches
Amorphous and crystalline In{sub 2}O{sub 3}-based transparent conducting films for photovoltaics

Energy Technology Data Exchange (ETDEWEB)

Koida, Takashi [Research Center for Photovoltaics, National Institute of Advanced Industrial Science and Technology, Tsukuba (Japan)

2017-02-15

We reported solar cells with reduced electrical and optical losses using hydrogen-doped In{sub 2}O{sub 3} (In{sub 2}O{sub 3}:H) transparent conducting layers with low sheet resistance and high transparence characteristics. The transparent conducting oxide (TCO) films were prepared by solid-phase crystallization of amorphous (a-) In{sub 2}O{sub 3}:H films grown by magnetron sputtering. The polycrystalline (poly-) In{sub 2}O{sub 3}:H films exhibited electron mobilities (over 100 cm{sup 2}V{sup -1} s{sup -1}) 2 and 3 times greater than those of conventional TCO films. This paper describes (i) the current status of the electrical properties of In{sub 2}O{sub 3}-based TCO; (ii) the structural and optoelectrical properties of the a-In{sub 2}O{sub 3}:H and poly-In{sub 2}O{sub 3}:H films, focusing on the inhomogeneity and stability characteristics of the films; and (iii) the electrical properties of bilayer TCO. The potential of these high mobility TCO films for solar cells was also described. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
{sup 4}He channelling studies of U{sub 4}O{sub 9}

Energy Technology Data Exchange (ETDEWEB)

Garrido, Frederico [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse, CNRS-IN2P3-Universite Paris-Sud, Batiments 104-108, 91405 Orsay (France)]. E-mail: garrido@csnsm.in2p3.fr; Nowicki, Lech [The Andrzej Soltan Institute for Nuclear Studies, Hoza 69, 00-681 Warsaw (Poland); Stonert, Anna [Andrzej Soltan Institute for Nuclear Studies, Hoza 69, 00-681 Warsaw (Poland); Pietraszko, Adam [Institute for Low Temperature and Structural Research, Polish Academy of Science, 50-422 Wroclaw (Poland); Wendler, Elke [Institut fuer Festkoerperphysik, Friedrich-Schiller Universitaet Jena, 07743 Jena (Germany)

2006-08-15

UO{sub 2} and U{sub 4}O{sub 9} single crystals were investigated by means of the {sup 4}He backscattering/channelling technique and the use of the 3032-keV elastic scattering resonance on {sup 16}O. Angular scans obtained for U{sub 4}O{sub 9} were interpreted in the framework of a recently published U{sub 4}O{sub 9} model. It was shown that the U{sub 4}O{sub 9} channelling data can be explained by the aggregation of some O atoms in cuboctahedral clusters, and the displacement of other (U and O) atoms from the UO{sub 2}-type sites. Basing on the combined use of the channelling technique and Monte Carlo simulations we suggest that the displacements of U atoms from their fluorite sites are larger than those determined by the neutron diffraction analysis.
Studies on high-pressure reaction of Er/sub 2/O/sub 3/ or Yb/sub 2/O/sub 3/ with VO/sub 2/

Energy Technology Data Exchange (ETDEWEB)

Shin-ike, T [Osaka Dental Coll., Hirakata (Japan); Adachi, G; Shiokawa, J; Shimada, M; Koizumi, M

1980-12-01

The reaction of erbium sesquioxide (Er/sub 2/O/sub 3/) or ytterbium sesquioxide (Yb/sub 2/O/sub 3/) with vanadium dioxide (VO/sub 2/) at 1400/sup 0/C and 50 kbar and 30 kbar pressures was studied. Quadrivalent vanadium ions were reduced to the trivalent state, erbium vanadate (ErVO/sub 3/) or ytterbium vanadate (YbVO/sub 3/) being obtained. The crystal structure of ErVO/sub 3/ obtained at 50 kbar pressure was vaterite-type isostructural with ErBO/sub 3/ belonging to a hexagonal system, and that obtained at 30 kbar calcite-type belonging to a rhombohedral (pseudo-hexagonal) system. In the reaction of Yb/sub 2/O/sub 3/ with VO/sub 2/ at high pressure, a perovskite-type crystal was obtained. The electrical and magnetic properties of the vaterite- and the calcite-type ErVO/sub 3/ were studied.
Oxygen redistribution in (UCe)Osub(2-x)

International Nuclear Information System (INIS)

Guedeney, Philippe.

1983-01-01

Redistribution of oxygen has been investigated in (Usub(0,7)Cesub(0,3))Osub(2-x) mixed oxide subjected to a temperature gradient in laboratory experiments, in order to apply the results to the nuclear fuel (UPu)Osub(2-x). Cylindrical sintered oxide specimens were exposed to temperature up to 1300 0 C with a longitudinal thermal gradient of about 400 0 C/cm. The most interesting feature of the experimental set-up is a solid-state electrochemical gauge (ThO 2 - Y 2 O 3 ), placed in the cold part of the sample which allows a continuous measurement of the oxygen activity. The experiments showed a fast oxygen migration down the thermal gradient. The calculations performed with a model based on solid-state thermodiffusion are in good agreement with experimental results. The heat of transport Q measured for bare samples reaches (7.2+-0.5)-kcal/mole. When the sample is coated with a tight fitting metallic cladding, an extra term Qe has to be added to the heat of transport Qe. This was interpreted as an electrotransport phenomena. On the same basis, calculations applied to radial oxygen redistribution in (UPu)Osub(2-x) seem to be adequate at least during the first stage of irradiation, taking Q=(20+-5)kcal/mole [fr
Studies on the Ln/sub 2/O/sub 3/ (Ln: rare-earth elements)-SrO-V/sub 2/O/sub 3/ system, 1. Phase diagrams at 1400/sup 0/C

Energy Technology Data Exchange (ETDEWEB)

Shin-ike, T [Osaka Dental Coll., Hirakata (Japan); Adachi, G; Shiokawa, J

1980-11-01

Rare-earth oxides Ln/sub 2/O/sub 3/ (Ln : Nd, Eu or Er), strontium oxide SrO and vanadium oxide V/sub 2/O/sub 3/ were mixed in a given molecular ratio, heated at 1400/sup 0/C in vacuum. The products were examined by an x-ray diffraction method to study the phase relations of the ternary systems. On heating, part of the trivalent vanadium was oxidized to the tetravalent state by atmospheric oxygen. In this experimental condition, the following ternary-phase solid solutions were identified: perovskite type Nd sub(1-x)Sr sub(x)VO sub(3-0.1x) (x > 0.3. cubic, x < 0.3: orthorhombic) and Eu sub(1-x)Sr sub(x)VO sub(3-0.1x) (x > 0.4: cubic, x < 0.4: orthorhombic), K/sub 2/NiF/sub 4/ type SrO.Nd sub(1-x)Sr sub(x)VO sub(3-0.1x) (x > 0.3) and SrO.Eu sub(1-x)Sr sub(x)VO sub(3-0.1x) (x > 0.4) and Eu/sub 3/Ti/sub 2/O/sub 7/ type SrO.2Nd sub(1-x)Sr sub(x)VO sub(3-0.1x) (x > 0.3) and SrO.2Eu sub(1-x)Sr sub(x)VO sub(3-0.1x) (x > 0.4). For the Er/sub 2/O/sub 3/-SrO-V/sub 2/O/sub 3/ system, only a mixture of Er/sub 2/O/sub 3/, SrVO sub(2.9), ErVO/sub 3/, SrO and V/sub 2/O/sub 3/ was obtained.
Evaluation of the urea content in the synthesis by combustion reaction of the NiAl{sub 2}O{sub 4} catalysts; Avaliacao do teor de ureia na sintese por reacao de combustao do catalisador NiAl{sub 2}O{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Leal, E.; Sousa, J.-P.L.M.L.; Costa, A.C.F.M.; Gama, L. [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Unidade Academica de Engenharia de Materiais; Argolo, F. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica; Sasaki, J.M. [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil). Dept. de Fisica

2009-07-01

The aim of this work is to evaluate the influence of the urea fuel in the structure and morphology of the NiAl{sub 2}O{sub 4} prepared by combustion reaction. The powders were prepared according to the propellants and explosives theory, using urea in the stoichiometric composition, with 10% of excess and deficiency of this fuel. The samples were characterized by XRD, FTIR, particle size distribution and textural analysis by nitrogen adsorption (BET/BJH). The DRX results showed the presence of NiAl{sub 2}O{sub 4} as major phase and traces of NiO for all the samples. Also show crystallites size between 13 and 21 nm. All the samples showed large agglomerates size distribution, with D{sub 50%} between 18.6 and 20.4 {mu}m, and morphology with irregular plates shape. The increase of the urea content caused an increase in the particle size and a reduction in the surface area, from 270 to 52 m{sup 2}/g. (author)
Structure of RbAlAs[sub 2]O[sub 7]. Structure de RbAlAs[sub 2]O[sub 7

Energy Technology Data Exchange (ETDEWEB)

Boughzala, H. (Dept. de Chimie, Faculte des Sciences, Tunis (Tunisia)); Driss, A. (Dept. de Chimie, Faculte des Sciences, Tunis (Tunisia)); Jouini, T. (Dept. de Chimie, Faculte des Sciences, Tunis (Tunisia))

1993-03-15

Rubidium aluminium pyroarsenate, M[sub r]=374.29, triclinic, P anti 1, a=8.233(5), b=6.34(2), c=6.241(5) A, [alpha]=102.6(1), [beta]=103.89(7), [gamma]=96.7(1) , V=303.9 A[sup 3], Z=2, D[sub m]=3.9(3) (pycnometry), D[sub x]=4.09 g cm[sup -3], [lambda](Ag K anti [alpha])=0.5608 A, [mu]=108.14 cm[sup -1], F(000)=344, T=296 K, R=0.049, wR=0.053 for 2193 reflections. The first structural investigation on a pyroarsenate is reported. It is built from AlAs[sub 2]O[sub 11] units comprising one AlO[sub 6] octahedron and one As[sub 2]O[sub 7] pyroarsenate group in which two AsO[sub 4] tetrahedra point in opposite directions. These units are connected by heteropolyhedral linkages to form a three-dimensional framework having intersecting tunnels where the Rb[sup +] ions are located. Although this structure is not isotypic with the phosphate analogues, it is closely related to that of the pyrophosphates of type I represented by KAlP[sub 2]O[sub 7]. (orig.).
Pt/Al/sub 2/O/sub 3/- carbon nanocomposite as a catalyst for fuel cells

International Nuclear Information System (INIS)

Naeem, R.; Ahmed, R.; Ansari, M.S.

2013-01-01

Catalysts comprising platinum nanoparticles (Pt NPs) on carbon support are used in fuel cells for the hydrogen and electricity production by electrochemical oxidation of methanol. However, the catalyst is not the best in terms of its performance. Considering role of the support as significant towards efficiency and durability of the catalyst, there is need for introducing novel support materials to replace carbon alone. Deposition of various metallic NPs on ceramic-carbon (hybrid) supports has been reported to improve thermal, mechanical, electrical and chemical properties of different types of catalyst. In search of better performing catalysts for proton exchange membrane fuel cells (PEMFCs), hybrid supports having different ceramic materials should be synthesized. In this regard Pt/Al/sub 2/O/sub 3/-Carbon (nanocomposites) have been synthesized and applied as promising catalysts in the PEMFCs; results obtained for the nanocomposites were compared with Pt/carbon and Pt/Al/sub 2/O/sub 3/. Vulcan carbon was purified and functionalized prior to use; presence of oxygen containing functional groups on carbon was established from the FTIR spectrum, Hybrid support (1:8 by weight ratio of ceramic and carbon) were already prepared in aqueous 2-propanol employing sonication method on to which Pt NPs (10% by weight in all the cases) were deposited by simple chemical reduction of PtCl/sub 4/ by NaBH/sub 4/ under controlled conditions. The catalysts were subjected to various characterization techniques like TGA (for thermal stability), EDX (for chemical composition), SEM (for surface morphology) and XRD (for cell-shape and -volume, material density and average crystalline size). Catalysts efficiencies for the methanol oxidation were investigated through cyclic voltammetery (CV) by comparing electrochemical surface area, peak current, exchange current density and rate constant in the acidic and basic media. Pt/Al/sub 2/O/sub 3/-carbon exhibited better catalytic efficiencies

Performance assessment of the catalyst ZnAl{sub 2}O{sub 4} and Cu/ZnAl{sub 2}O{sub 4} esterification reaction fatty acid in biodiesel; Avaliacao do desempenho do catalisador ZnAl{sub 2}O{sub 4} e Cu/ZnAl{sub 2}O{sub 4} na reacao de estereficacao de acidos graxos em biodiesel

Energy Technology Data Exchange (ETDEWEB)

Feitosa, A.C.; Dantas, J.; Costa, A.C.M.F., E-mail: alexcaval2@hotmail.com [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Departamento de Engenharia de Materiais; Barbosa, D.C.; Meneghetti, S.M.P. [Universidade Federal de Alagoas (UFAL), Maceio, AL (Brazil). Dept. de Quimica

2012-07-01

This study aims to evaluate the performance of the Cu/ZnAl{sub 2}O{sub 4} and ZnAl{sub 2}O{sub 4} methyl esterification of fatty acids of soybean oil into biodiesel. The ZnAl{sub 2}O{sub 4} was synthesized by combustion reaction and then the sample was wet impregnated with a copper source. The samples were characterized by XRD, SEM, textural analysis and catalytic tests bench. The characterization results showed that the samples showed characteristic diffraction peaks spinel, with the characteristic of mesoporous material (10-250 Å), particles in the form of blocks and slabs of hard point. The results showed that the conversion impregnation of copper has increased by 17% conversion to biodiesel. (author)
Late production of hydrocarbon gases in sedimentary basins: kinetic and isotopic study; Genese tardive des gaz hydrocarbures dans les bassins sedimentaires: etude cinetique et isotopique

Energy Technology Data Exchange (ETDEWEB)

Lorant, F.

1999-06-23

to describe more precisely these reactions, additional pyrolysis experiments were performed on an aromatic compound, representative of the chemical structure of mature kerogens: the 1-methyl-pyrene. The data show that the methane is mainly produced during secondary and tertiary mechanisms, following to global succeeding stages: E{sub 1} = 56.7 kcal/mol and A{sub 1} = 8.52 x 10{sup 12} s{sup -1}, E{sub 2} = 49.5 kcal/mol and A{sub 2} 2.48 x 10{sup 9} s{sup -1}. By analogy, it was established that the three reactions of late methane generation, as observed by pyrolyzing mature kerogens, are respectively related to beta-scission, demethylation and cokefaction processes. In other respects, the late methane is characterized by {delta}{sup 13}C values between -36 and -24 0/00{sub PDB} (experimental conditions), and for the Type II kerogen by a reversal of the isotopic fractionation between the gas and its source at the high maturity levels: {delta}{sup 13}C{sub CH4/kerogene} = -10 to +2 0/00{sub PDB}. Such an uncommon {delta}{sup 13}C evolution was not observed during the pyrolysis of the I-methyl-pyrene, the generated methane being, on the contrary, strongly {sup 12}C-enriched compared to its source ({delta}{sup 13}C{sub CH4/1-MPy} = -35 to -19 0/00{sub PDB}). Nevertheless, by coupling a model of isotopic fractionation, based on the assumption of strictly kinetically-controlled effects, to the kinetic scheme previously generated, it was shown that the differences of isotopic signature between the model compound and the kerogens are mainly due to highly contrasted precursor effects (i.e. {delta}{sup 13}C of the functional groups from which the methane originates) specific to demethylation processes. Besides the elaboration of a methodology for the acquisition of kinetic, stoichiometric and isotopic parameters specific to the generation of late methane, this work has allowed the validation of a model of isotopic fractionation, especially by emphasizing the synergy between
Electromagnetic and microwave absorption properties of BaMg{sub x}Co{sub 1−x}TiFe{sub 10}O{sub 19}

Energy Technology Data Exchange (ETDEWEB)

Chen, Jing [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010 (China); Meng, Pingyuan [Huzhou Innovation Center of Advanced Materials, Shanghai Institute of Ceramics Chinese Academy of Sciences, Huzhou 215100 (China); Wang, Meiling [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010 (China); Zhou, Guanchen [School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010 (China); Wang, Xinqing [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010 (China); Xu, Guangliang, E-mail: xuguangliang@swust.edu.cn [School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010 (China)

2016-09-15

To improve the impedance matching and then achieve a better microwave absorption performance in electromagnetic absorber, the Mg{sup 2+} was added to occupy the sites of Co{sup 2+} in hexagonal-type ferrite BaCoTiFe{sub 10}O{sub 19}. BaMg{sub x}Co{sub 1−x}TiFe{sub 10}O{sub 19} were synthesized by a simple sol-gel combustion technique and the phase of BaMg{sub x}Co{sub 1−x}TiFe{sub 10}O{sub 19} was confirmed by X-ray diffraction analysis (XRD). The grain size of BaMg{sub x}Co{sub 1−x}TiFe{sub 10}O{sub 19} was in the range of 100–400 nm and crystal particles were refined with the augment of doped Mg{sup 2+}. Based on the static magnetic measurement, the coercivity (H{sub c}) increased and the saturation magnetization (M{sub s}) decreased as the x increased. Moreover, it was found that BaMg{sub 0.4}Co{sub 0.6}TiFe{sub 10}O{sub 19} possessed a maximum reflection loss of −33.7 dB with a matching thickness of 2.0 mm measured by the vector net-analyzer in the frequency of 0.5–18 GHz, which also had a bandwidth below −20 dB ranging from 11.5 GHz to 17.2 GHz. Meanwhile, the permeability of the prepared ferrites could be adjusted and a proper match was provided between dielectric and magnetic properties by controlling the doped content of Mg{sup 2+}, which would be significant to the application of BaMg{sub x}Co{sub 1−x}TiFe{sub 10}O{sub 19} in the field of the microwave absorbing materials. - Highlights: • The Mg{sup 2+} ions were first employed to occupy the place of Co{sup 2+} ions in BaCoTiFe{sub 10}O{sub 19}. • The grains were refined as Co substitution by Mg in ferrite. • The peaks of complex permeability shift to high frequency with Mg{sup 2+} substituted. • The coercivity increased and saturation magnetization slightly decreased. • Substitution of Mg{sup 2+} enhanced microwave absorption and broadened bandwidth.
Effects of Al{sub 2}O{sub 3} phase and Cl component on dehydrogenation of propane

Energy Technology Data Exchange (ETDEWEB)

Liu, Jie; Liu, Changcheng; Ma, Aizeng; Rong, Junfeng; Da, Zhijian, E-mail: dazhijianripp@163.com; Zheng, Aiguo; Qin, Ling

2016-04-15

Graphical abstract: - Highlights: • Comparative study of Al{sub 2}O{sub 3} phase on dehydrogenation of propane was implemented. • Pore structures and acid properties of Pt-Al{sub 2}O{sub 3} are correlated to the activities. • Pt-θ-Al{sub 2}O{sub 3} with abundant Cl content shows the highest activity and stability. - Abstract: The effects of two Al{sub 2}O{sub 3} phases, γ- and θ-Al{sub 2}O{sub 3}, and Cl component on the performances of Pt-Al{sub 2}O{sub 3} catalysts in the dehydrogenation of propane were investigated in this work. The catalysts were systematically characterized by various techniques, such as scanning transmission electron microscopy (STEM), temperature-programmed desorption with ammonia as probe molecules (NH{sub 3}-TPD) and temperature-programmed oxidation (TPO). The characterizations and catalytic results show that: (i) the pore structures and acid properties of the two Al{sub 2}O{sub 3} phases can change the quantity, location and property of the carbon deposition, (ii) the existence of Cl plays a significant role on the agglomeration of Pt particles and carbon deposition, which further influence the catalytic performances of Pt-Al{sub 2}O{sub 3} catalysts with different support phases for propane dehydrogenation.
Assessment of coal combustion in O{sub 2}+CO{sub 2} by equilibrium calculations

Energy Technology Data Exchange (ETDEWEB)

Zheng, Ligang [Natural Resources Canada, CANMET Energy Technology Centre, 1 Haanel Drive, Nepean, ON (Canada); Furimsky, Edward [IMAF Group, 184 Marlborough Avenue, Ottawa, ON (Canada)

2003-04-15

The facility for analysis of chemical thermodynamics (F*A*C*T) method based on the Gibbs energy minimization principle was used for the environmental assessment of coal combustion in O{sub 2}+CO{sub 2} mixture compared with that in air. For the former case, the calculations predict higher emissions of CO and lower emissions of NO{sub x}. For both combustion media, SO{sub x} emissions are governed by O{sub 2} concentration, whereas distribution of trace metals was unaffected when O{sub 2} concentration in the O{sub 2}+CO{sub 2} mixture approached that in air. The effect of O{sub 2}+CO{sub 2} mixture on the distribution of chlorine- and alkali-containing compounds in the vapor phase was minor compared with that in air. In spite of the large excess of CO{sub 2} in combustion medium, sulfation was the predominant reaction occurring in ash.
Structure of Na/sub 2/As/sub 4/O/sub 11/

Energy Technology Data Exchange (ETDEWEB)

Driss, A.; Jouini, T.; Omezzine, M.

1988-05-15

Disodium tetraarsenate, M/sub r/=521.66, monoclinic, C2/c, a=9.049(3), b=8.287(3), c=11.508(5) A, ..beta..=102.74(4)/sup 0/, V=842(2) A/sup 3/, Z=4, D/sub m/=4.06 (by flotation), D/sub x/=4.11 Mg m/sup -3/, lambda(AgK anti ..cap alpha..)=0.5608 A, ..mu..=8.6 mm/sup -1/, F(000)=968, room temperature, final R=0.046 and ..omega..R=0.048 for 1153 independent reflections. The main feature of this structure is the existence of the first three-dimensional anion (As/sub 4/O/sub 11/)/sub n//sup 2n-/ in the chemistry of the condensed arsenates. It has the lowest O/As ratio (2.75) of the known arsenates showing marked condensation: all the O atoms are shared except one per AsO/sub 4/ tetrahedron. The structural unit is the As/sub 4/O/sub 15/ ring with point symmetry 2, built up from alternate AsO/sub 4/ tetrahedra and AsO/sub 6/ octahedra sharing corners. In addition, the two octahedra share one O atom located on the 2 axis. The As/sub 4/O/sub 15/ ring derives from the known centrosymmetric As/sub 4/O/sub 14/ ring by the cleavage of one As-O-As linkage between the two octahedra of the ring to form two new As-O-As linkages with AsO/sub 4/ tetrahedra connecting two rings, leading to a decrease of the O/As ratio. The As/sub 4/O/sub 15/ rings are further linked by sharing edges of AsO/sub 6/ octahedra to form a three-dimensional framework. This completes the set of the already known arrangements of the As/sub 4/O/sub 14/ ring (isolated units, infinite chains, layers).
Enrichment of Sc{sub 2}O{sub 3} and TiO{sub 2} from bauxite ore residues

Energy Technology Data Exchange (ETDEWEB)

Deng, Bona; Li, Guanghui, E-mail: liguangh@csu.edu.cn; Luo, Jun; Ye, Qing; Liu, Mingxia; Peng, Zhiwei; Jiang, Tao

2017-06-05

Highlights: • Sc{sub 2}O{sub 3} and TiO{sub 2} from bauxite ore residue were successfully enriched. • H{sub 3}PO{sub 4} and NaOH were efficient for enriching Sc{sub 2}O{sub 3} and TiO{sub 2} by removing SiO{sub 2}, Al{sub 2}O{sub 3}, and partial Fe{sub 2}O{sub 3} and CaO. • Enriching mechanism of Sc{sub 2}O{sub 3} and TiO{sub 2} was explicitly explained. - Abstract: As a major byproduct generated in the alumina industry, bauxite ore residue is an important reserve of scandium and titanium. In this study, the feasibility and mechanism of enriching Sc{sub 2}O{sub 3} and TiO{sub 2} from a non-magnetic material, which was obtained from carbothermal reductive roasting and magnetic separation of bauxite ore residue, were investigated based on a two-step (acidic and alkali) leaching process. It was revealed that approximately 78% SiO{sub 2} and 30–40% of CaO, FeO and Al{sub 2}O{sub 3} were removed from a non-magnetic material with 0.0134 wt.% Sc{sub 2}O{sub 3} and 7.64 wt.% TiO{sub 2} by phosphoric acidic leaching, while about 95% Al{sub 2}O{sub 3} and P{sub 2}O{sub 5} were further leached by subsequent sodium hydroxide leaching of the upper-stream leach residue. A Sc{sub 2}O{sub 3}-, TiO{sub 2}- rich material containing 0.044 wt.% Sc{sub 2}O{sub 3} and 25.5 wt.% TiO{sub 2} was obtained, the recovery and the enrichment factor of Sc{sub 2}O{sub 3} and TiO{sub 2} were about 85% and 5, respectively. The enrichment of Sc{sub 2}O{sub 3} was attributed to higher pH (>3.3) of phosphoric acid solution than its dissolution pH{sup 0}, and the enrichment of TiO{sub 2} was mainly associated with the insoluble perovskite (CaTiO{sub 3}) in the acidic solution at ambient temperature. As Sc{sub 2}O{sub 3} and TiO{sub 2} cannot be dissolved in the alkali solution, they were further enriched in the leach residue.
From Ba{sub 3}Ta{sub 5}O{sub 14}N to LaBa{sub 2}Ta{sub 5}O{sub 13}N{sub 2}: Decreasing the optical band gap of a photocatalyst

Energy Technology Data Exchange (ETDEWEB)

Anke, B. [Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin (Germany); Bredow, T. [Mulliken Center for Theoretical Chemistry, Institut für Physikalische und Theoretische Chemie, Universität Bonn, Beringstr. 4, 53115 Bonn (Germany); Pilarski, M.; Wark, M. [Institut für Chemie, Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Str. 9-11, 26129 Oldenburg (Germany); Lerch, M., E-mail: martin.lerch@tu-berlin.de [Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin (Germany)

2017-02-15

Yellow LaBa{sub 2}Ta{sub 5}O{sub 13}N{sub 2} was successfully synthesized as phase-pure material crystallizing isostructurally to previously reported Ba{sub 3}Ta{sub 5}O{sub 14}N and mixed-valence Ba{sub 3}Ta{sup V}{sub 4}Ta{sup IV}O{sub 15}. The electronic structure of LaBa{sub 2}Ta{sub 5}O{sub 13}N{sub 2} was studied theoretically with the range-separated hybrid method HSE06. The most stable structure was obtained when lanthanum was placed on 2a and nitrogen on 4h sites confirming Pauling's second rule. By incorporating nitrogen, the measured band gap decreases from ∼3.8 eV for the oxide via 2.74 eV for Ba{sub 3}Ta{sub 5}O{sub 14}N to 2.63 eV for the new oxide nitride, giving rise to an absorption band well in the visible-light region. Calculated fundamental band gaps confirm the experimental trend. The atom-projected density of states has large contributions from N2p orbitals close to the valence band edge. These are responsible for the observed band gap reduction. Photocatalytic hydrogen formation was investigated and compared with that of Ba{sub 3}Ta{sub 5}O{sub 14}N revealing significantly higher activity for LaBa{sub 2}Ta{sub 5}O{sub 13}N{sub 2} under UV-light. - Graphical abstract: X-ray powder diffraction pattern of LaBa{sub 2}Ta{sub 5}O{sub 13}N{sub 2} with the results of the Rietveld refinements. Inset: Unit cell of LaBa{sub 2}Ta{sub 5}O{sub 13}N{sub 2} and polyhedral representation of the crystal structure. - Highlights: • Synthesis of a new oxide nitride LaBa{sub 2}Ta{sub 5}O{sub 13}N{sub 2}. • Refinement of the crystal structure. • Quantum chemical calculations provided band gap close to the measured value. • New phase shows a higher photocatalytic H{sub 2} evolution rate compared to prior tested Ba{sub 3}Ta{sub 5}O{sub 14}N.
Spectroscopic and dielectric properties of titanium doped MgO-Al{sub 2}O{sub 3}-B{sub 2}O{sub 3} glass system

Energy Technology Data Exchange (ETDEWEB)

Raju, G Naga; Ramesh, N Ch; Naresh, P; Krishna, T L; Srinivasulu, K; Sudhkar, K S V; Rao, P Venkateswara, E-mail: gnag_9@rediffmail.com [Department of Physics, Acharya Nagarjuna University-Nuzvid Campus, Nuzvid - 521 201 (India)

2009-07-15

In this paper we have reported the influence of titanium ions on different spectroscopic and dielectric properties of MgO-Al{sub 2}O{sub 3}-B{sub 2}O{sub 3} glasses. The analysis of result of all these studies has indicated that as the concentration of TiO{sub 2} increased in the glass matrix, there is a gradual transformation of titanium ions from octahedral position to tetrahedral positions and cause to increase the rigidity of glass network.
Electrical properties of reactive-ion-sputtered Al{sub 2}O{sub 3} on 4H-SiC

Energy Technology Data Exchange (ETDEWEB)

Shukla, Madhup, E-mail: madhup.iit@gmail.com [Microelectronics and MEMS Laboratory, Electrical Engineering Department, Indian Institute of Technology Madras, Chennai 600036 (India); Dutta, Gourab [Microelectronics and MEMS Laboratory, Electrical Engineering Department, Indian Institute of Technology Madras, Chennai 600036 (India); Mannam, Ramanjaneyulu [Department of Physics and Nano Functional Materials Technology Centre, Indian Institute of Technology Madras, Chennai 600036 (India); DasGupta, Nandita [Microelectronics and MEMS Laboratory, Electrical Engineering Department, Indian Institute of Technology Madras, Chennai 600036 (India)

2016-05-31

Al{sub 2}O{sub 3} was deposited on n-type 4H-SiC by reactive-ion-sputtering (RIS) at room temperature using aluminum target and oxygen as a reactant gas. Post deposition oxygen annealing was carried out at a temperature of 1100 °C. Metal-oxide-semiconductor (MOS) test structures were fabricated on 4H-SiC using RIS-Al{sub 2}O{sub 3} as gate dielectric. The C-V characteristics reveal a significant reduction in flat band voltage for oxygen annealed RIS-Al{sub 2}O{sub 3} samples (V{sub fb} = 1.95 V) compared to as-deposited Al{sub 2}O{sub 3} samples (V{sub fb} > 10 V), suggesting a reduction in negative oxide charge after oxygen annealing. Oxygen annealed RIS-Al{sub 2}O{sub 3} samples also showed significant improvement in I-V characteristics compared to as-deposited RIS-Al{sub 2}O{sub 3} samples. A systematic analysis was carried out to investigate the leakage current mechanisms present in oxygen annealed RIS-Al{sub 2}O{sub 3} on 4H-SiC at higher gate electric field and at different operating temperature. For measurement temperature (T) < 303 K, Fowler–Nordheim (FN) tunneling was found to be the dominant leakage mechanism and for higher temperature (T ≥ 303 K), a combination of FN tunneling and Poole-Frenkel (PF) emission was confirmed. The improvement in I-V characteristics of oxygen annealed RIS-Al{sub 2}O{sub 3}/4H-SiC MOS devices is attributed to large effective barrier height (Φ{sub B} = 2.53 eV) at Al{sub 2}O{sub 3}/SiC interface, due to the formation of an interfacial SiO{sub 2} layer during oxygen annealing, as confirmed from X-ray Photoelectron Spectroscopy results. Further improvement in C-V characteristics for oxygen annealed RIS-Al{sub 2}O{sub 3}/4H-SiC MOS devices was observed after forming gas annealing at 400 °C. - Highlights: • O{sub 2} annealed RIS-Al{sub 2}O{sub 3} on 4H-SiC showed better performance than other reported result. • FN, FN + PF tunneling was found in O{sub 2} annealed RIS-Al{sub 2}O{sub 3} for different temp. ranges. • Al
Effect of iron doping on the magnetic properties of TbMn{sub 2}O{sub 5}

Energy Technology Data Exchange (ETDEWEB)

Han, T.-C. [Center for Condensed Matter Sciences, National Taiwan University, Taipei 106, Taiwan (China)]. E-mail: taichun_han@yahoo.com.tw; Lin, Jauyn Grace [Center for Condensed Matter Sciences, National Taiwan University, Taipei 106, Taiwan (China) and Center for Nanostorage Research, National Taiwan University, Taipei 106, Taiwan (China)]. E-mail: jglin@ccms.ntu.edu.tw

2007-03-15

We synthesized a series of TbFe{sub x}Mn{sub 2-x}O{sub 5} (0{<=}x{<=}0.2) samples and studied the effect of the Fe-doping on their magnetic properties. X-ray diffraction patterns indicate a pure orthorhombic structure with space group Pbam for all the samples. Based on the data of temperature- and field-dependent magnetization, M(T) and M(H) curves, it is found that the magnetic moment enhances with increase in the Fe-content in TbMn{sub 2}O{sub 5}. With increase in the Fe-content from 0 to 0.2, the magnetic moment increases progressively from 0.014 to 0.030 {mu} {sub Bohr} p.f.u. at room temperature (RT). Particularly for the TbFe{sub 0.2}Mn{sub 1.8}O{sub 5} sample, a current-voltage curve displays a nonlinear behavior at RT. If a strong coupling between magnetic moment and electric polarization exists, the Fe-doped sample may have a higher polarization/ferroelectric effect, which should be a great advantage for the future application of the spintronics devices.
A 3d-4f complex constructed by the assembly of a cationic template, [Cu(en){sub 2}]{sup 2+}, and a 3D anionic coordination polymer, [Sm{sub 2}(C{sub 2}O{sub 4}){sub 3}(C{sub 5}O{sub 5})(H{sub 2}O){sub 2}]{sup 2-}

Energy Technology Data Exchange (ETDEWEB)

Ke, Szu-Yu; Yeh, Chang-Tsung; Wang, Chih-Chieh [Department of Chemistry, Soochow University, Taipei, Taiwan (China); Lee, Gene-Hsiang [Instrumentation Center, National Taiwan University, Taipei, Taiwan (China); Sheu, Hwo-Shuenn [National Synchrotron Radiation Research Center, Hsinchu, Taiwan (China)

2017-05-18

A three-dimensional (3D) 3d-4f complex, [Cu(en){sub 2}][Sm{sub 2}(C{sub 5}O{sub 5})(C{sub 2}O{sub 4}){sub 3}(H{sub 2}O){sub 2}].8H{sub 2}O (1) (en = ethylenediamine, C{sub 5}O{sub 5}{sup 2-} = dianion of 4,5-dihydroxycyclopent-4-ene-1,2,3-trione), were prepared via the in-situ ring-opening oxidation reaction of croconate in the presence of the template-directed complex, [Cu(en){sub 2}]{sup 2+} cation. The structural characterization determined by X-ray diffraction determination reveals that the 3D anionic coordination polymer of [Sm{sub 2}(C{sub 2}O{sub 4}){sub 3}(C{sub 5}O{sub 5})(H{sub 2}O){sub 2}]{sup 2-} in 1 can be describe in terms of in-plane 2D honeycomb-like [Sm{sub 2}(C{sub 2}O{sub 4}){sub 3}] layered frameworks bridged by oxalate with bis-chelating mode, being mutually interlinked via the bridge of μ{sub 1,2,3,4}-croconate ligands with bis-chelating coordination mode to complete the 3D open framework, which gives rise to 1D channels with pore size of 14.023 x 11.893 Aa (longest atom-atom contact distances) along the b axis. The structure-directing complex, [Cu(en){sub 2}]{sup 2+}, and solvated water molecules are resided into these honeycomb-type hexagonal channels. The thermal stability of 1 was further studied by TGA and in-situ powder X-ray diffraction measurement. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Magnetic behavior of biosynthesized Co{sub 3}O{sub 4} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Diallo, A., E-mail: abdoulayediallosn@gmail.com [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation,1 Old Faure road, Somerset West 7129, PO Box 722, Somerset West, Western Cape (South Africa); Centre for Nano Science and Nanotechnology, K.S. Rangasamy College of Technology, Tiruchengode 63721, Tamil Nadu (India); Laboratoire de Photonique et de Nano-Fabrication, Faculté des sciences et Techniques, Université Cheikh Anta Diop de Dakar (UCAD), B.P. 25114, Dakar-Fann Dakar (Senegal); Doyle, T.B. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation,1 Old Faure road, Somerset West 7129, PO Box 722, Somerset West, Western Cape (South Africa); School of Chemistry and Physics, University of KwaZulu-Natal, Durban 4001 (South Africa); Mothudi, B.M.; Manikandan, E. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation,1 Old Faure road, Somerset West 7129, PO Box 722, Somerset West, Western Cape (South Africa); and others

2017-02-15

This contribution reports for the 1st time on the magnetic behavior of CO{sub 3}O{sub 4} nanoparticles synthesized by a “green” process using an Aspalathus linearis’ leaves natural extract. More accurately magnetic behavior of CO{sub 3}O{sub 4} nanoparticles successfully biosynthesized was investigated using vibrating sample magnetometer. The magnetization behavior for the samples manifests a combination of size dependent antiferromagnetic and paramagnetic behaviors, respectively, for the core and shell of the nanoparticles. - Highlights: • 1{sup st} report on magnetic behavior of Co3O4 nanoparticles via Aspalathus linearis. • Co{sub 3}O{sub 4} nanoparticles manifest size-dependent antiferromagnetic & paramagnetic behaviors. • Antiferromagnetic & paramagnetic behaviors were confirmed by VSM.
Magnetic biodegradable Fe{sub 3}O{sub 4}/CS/PVA nanofibrous membranes for bone regeneration

Energy Technology Data Exchange (ETDEWEB)

Wei Yan; Zhang Xuehui; Hu Xiaoyang; Deng Xuliang [Department of Geriatric Dentistry, School and Hospital of Stomatology, Peking University, Beijing, 100081 (China); Song Yu; Lin Yuanhua [State Key Laboratory of New Ceramics and Fine Processing, Department of Materials Science and Engineering, Tsinghua University, Beijing, 100084 (China); Han Bing [Department of Orthodontics, School and Hospital of Stomatology, Peking University, Beijing, 100081 (China); Wang Xinzhi, E-mail: kqdengxuliang@bjmu.edu.cn [Department of Prosthodontics, School and Hospital of Stomatology, Peking University, Beijing, 100081 (China)

2011-10-15

In recent years, interest in magnetic biomimetic scaffolds for tissue engineering has increased considerably. The aim of this study is to develop magnetic biodegradable fibrous materials with potential use in bone regeneration. Magnetic biodegradable Fe{sub 3}O{sub 4}/chitosan (CS)/poly vinyl alcohol (PVA) nanofibrous membranes were achieved by electrospinning with average fiber diameters ranging from 230 to 380 nm and porosity of 83.9-85.1%. The influences of polymer concentration, applied voltage and Fe{sub 3}O{sub 4} nanoparticles loading on the fabrication of nanofibers were investigated. The polymer concentration of 4.5 wt%, applied voltage of 20 kV and Fe{sub 3}O{sub 4} nanoparticles loading of lower than 5 wt% could produce homogeneous, smooth and continuous Fe{sub 3}O{sub 4}/CS/PVA nanofibrous membranes. X-ray diffraction (XRD) data confirmed that the crystalline structure of the Fe{sub 3}O{sub 4}, CS and PVA were maintained during electrospinning process. Fourier transform infrared spectroscopy (FT-IR) demonstrated that the Fe{sub 3}O{sub 4} loading up to 5 wt% did not change the functional groups of CS/PVA greatly. Transmission electron microscopy (TEM) showed islets of Fe{sub 3}O{sub 4} nanoparticles evenly distributed in the fibers. Weak ferrimagnetic behaviors of membranes were revealed by vibrating sample magnetometer (VSM) test. Tensile test exhibited Young's modulus of membranes that were gradually enhanced with the increase of Fe{sub 3}O{sub 4} nanoparticles loading, while ultimate tensile stress and ultimate strain were slightly reduced by Fe{sub 3}O{sub 4} nanoparticles loading of 5%. Additionally, MG63 human osteoblast-like cells were seeded on the magnetic nanofibrous membranes to evaluate their bone biocompatibility. Cell growth dynamics according to MTT assay and scanning electron microscopy (SEM) observation exhibited good cell adhesion and proliferation, suggesting that this magnetic biodegradable Fe{sub 3}O{sub 4}/CS/PVA nanofibrous
Gas-sensing properties of In{sub 2}O{sub 3} films modified with gold nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Korotcenkov, G., E-mail: ghkoro@yahoo.com [School of Material Science and Engineering, Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of); Brinzari, V. [Department of Theoretical Physics, State University of Moldova, Chisinau, Republic of Moldova (Moldova, Republic of); Han, S.H. [Division of Maritime Transportation System, Mokpo National Maritime University, Mokpo (Korea, Republic of); Cho, B.K., E-mail: chobk@gist.ac.kr [School of Material Science and Engineering, Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of)

2016-06-01

A study of the surface and gas–sensitive properties of In{sub 2}O{sub 3} films modified with gold nanoparticles and synthesized by the successive ionic layer deposition (SILD) method was conducted. In{sub 2}O{sub 3} films were prepared using the spray pyrolysis method. The gas-sensing characteristics were tested using CO, H{sub 2}, and O{sub 3} as target gases. It has been shown that the surface modification with gold nanoparticles gives the opportunity to optimize the response of In{sub 2}O{sub 3}-based gas sensors to both reducing (CO, H{sub 2}) and oxidizing (O{sub 3}) gases. It has been found that the sensitizing effect during ozone detection was significantly higher than the effect during CO and H{sub 2} detection. It has been demonstrated that the sensitizing effect depended on the number of SILD cycles used for gold nanoparticle deposition and was maximal for the In{sub 2}O{sub 3} surface decorated with gold nanoparticles with the smallest size. The mechanism of the gold nanoparticles' influence on the gas-sensing properties of the In{sub 2}O{sub 3} films is also discussed. It is suggested that to explain the observed effects, we have to consider both the “electronic” and “chemical” mechanisms of sensitization. Suggestions for studies to be carried out to further improve both the understanding of the nature of the gas-sensitive effects and the parameters of In{sub 2}O{sub 3}:Au-based gas sensors are also formulated. - Highlights: • In{sub 2}O{sub 3} gas sensors modified with gold nanoparticles using SILD method are studied. • AuNPs exhibit activity during interaction with either reducing or oxidizing gases. • Maximal effect of optimization is observed during ozone detection. • Sensitizing effect depends on the number of SILD cycles. • Proposed mechanisms explain effects observed in the In{sub 2}O{sub 3}:Au based gas sensors.
Hot corrosion of the ceramic composite coating Ni{sub 3}Al-Al{sub 2}O{sub 3}-Al{sub 2}O{sub 3}/MgO plasma sprayed on 316L stainless steel

Energy Technology Data Exchange (ETDEWEB)

Shirazi, Amir Khodaparast; Kiahosseini, Seyed Rahim [Islamic Azad Univ., Damghan (Iran, Islamic Republic of). Dept. of Engineering

2017-08-15

Ni{sub 3}Al-Al{sub 2}O{sub 3}-Al{sub 2}O{sub 3}/MgO three-layered coatings with thicknesses of 50, 100, and 150 μm for Al{sub 2}O{sub 3}/MgO and 100 μm for the other layers were deposited on 316L stainless steel using plasma spraying. X-ray diffraction, atomic force microscopy, furnace hot corrosion testing in the presence of a mixture of Na{sub 2}SO{sub 4} and V{sub 2}O{sub 5} corrosive salts and scanning electron microscopy were used to determine the structural, morphological and hot corrosion resistance of samples. Results revealed that the crystalline grains of MgO and Al{sub 2}O{sub 3} coating were very small. Weight loss due to hot corrosion decreased from approximately 4.267 g for 316L stainless steel without coating to 2.058 g. The samples with 150 μm outer coating showed improved resistance with the increase in outer layer thickness. Scanning electron microscopy of the coated surface revealed that the coating's resistance to hot corrosion is related to the thickness and the grain size of Al{sub 2}O{sub 3}/MgO coatings.
Microstructure and temperature dependence of the microhardness of W–4V–1La{sub 2}O{sub 3} and W–4Ti–1La{sub 2}O{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Savoini, B., E-mail: begona.savoini@uc3m.es; Martínez, J.; Muñoz, A.; Monge, M.A.; Pareja, R.

2013-11-15

W–4V–1La{sub 2}O{sub 3} and W–4Ti–1La{sub 2}O{sub 3} (wt.%) alloys have been produced by mechanical alloying and subsequent hot isostatic pressing. Electron microscopy observations revealed that these alloys exhibit a submicron grain structure with a dispersion of La oxide nanoparticles. Large V or Ti pools with martensitic characteristics are found segregated in the interstices between the W particles of the respective alloys. Microhardness tests were carried out over the temperature range 300–1073 K in vacuum. The microhardness–temperature curve for W–4V–1La{sub 2}O{sub 3} exhibited the expected decreasing trend with increasing temperature although the microhardness stayed constant between ∼473 and 773 K. The W–4Ti–1La{sub 2}O{sub 3} presented quite different temperature dependence with an anomalous microhardness increase for temperatures above ∼473 K.
Mn{sub 2}O{sub 3}/carbon aerogel microbead composites synthesized by in situ coating method for supercapacitors

Energy Technology Data Exchange (ETDEWEB)

Wang Xingyan, E-mail: wxianyou@yahoo.com [Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, Chemistry School, Xiangtan University, Hunan, Xiangtan 411105 (China); Hunan Institute of Humanities Science and Technology, Loudi 417000 (China); Key Laboratory of Materials Design and Preparation Technology of Hunan, Xiangtan 411105 (China); Liu Li [Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, Chemistry School, Xiangtan University, Hunan, Xiangtan 411105 (China); Wang Xianyou, E-mail: wqinyan801@yahoo.com.cn [Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, Chemistry School, Xiangtan University, Hunan, Xiangtan 411105 (China); Key Laboratory of Materials Design and Preparation Technology of Hunan, Xiangtan 411105 (China); Yi Lanhua [Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, Chemistry School, Xiangtan University, Hunan, Xiangtan 411105 (China); Hu Chuanyue [Hunan Institute of Humanities Science and Technology, Loudi 417000 (China); Zhang Xiaoyan [Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, Chemistry School, Xiangtan University, Hunan, Xiangtan 411105 (China)

2011-09-15

Highlights: > Mn{sub 2}O{sub 3}/CAMB composite materials for supercapacitor were prepared by in situ coating method. > The optimum amount of Mn{sub 2}O{sub 3} in Mn{sub 2}O{sub 3}/CAMB composite is 10 wt%. > Coating nano-sized Mn{sub 2}O{sub 3} on the CAMB could improve the supercapacitive behaviors of composites. - Abstract: A series of Mn{sub 2}O{sub 3}/carbon aerogel microbead (Mn{sub 2}O{sub 3}/CAMB) composites for supercapacitor electrodes have been synthesized by in situ encapsulation method. The structure and morphology of Mn{sub 2}O{sub 3}/CAMB are characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectrum and scanning electron microscopy (SEM). Electrochemical performances of the synthesized composites are evaluated by cyclic voltammetry and galvanostatic charge/discharge measurement. All the composites with different Mn{sub 2}O{sub 3} contents show higher specific capacitance than pure CAMB due to the pseudo-capacitance of the Mn{sub 2}O{sub 3} particles dispersed on the surface of CAMB. The highest specific capacitance is up to 368.01 F g{sup -1} when 10 wt% Mn{sub 2}O{sub 3} is coated on the surface of CAMB. Besides, 10%-Mn{sub 2}O{sub 3}/CAMB supercapacitor exhibits excellent cyclic stability, the specific capacitance still retains 90% of initial capacitance over 5000 cycles.
Compatibility of yttria (Y{sub 2}O{sub 3}) with liquid lithium

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Mitsuyama, Takaaki; Yoneoka, Toshiaki; Terai, Takayuki; Tanaka, Satoru [Tokyo Univ. (Japan). Faculty of Engineering

1996-10-01

Compatibility of Y{sub 2}O{sub 3} sintered specimens with liquid lithium was tested at 773K. No configuration change was observed with a slight increase of thickness for 1419 hr. Lithium-yttrium complex oxide (LiYO{sub 2}) was formed on the surface, and the inner part changed to gray or black nonstoichiometric Y{sub 2}O{sub 3-X} with lower electrical resistibility. It is concluded that Y{sub 2}O{sub 3} has a possibility as a ceramic coating material for liquid blankets if it can be made into a dense coating on the surface of piping materials. (author)
Fe{sub 3}O{sub 4}/carbon nanocomposite: Investigation of capacitive & magnetic properties for supercapacitor applications

Energy Technology Data Exchange (ETDEWEB)

Sinan, Neriman, E-mail: sinanneriman@gmail.com [Department of Advanced Technologies, Materials Science and Engineering Program, Bursa Technical University, Yildirim 16310, Bursa (Turkey); Unur, Ece, E-mail: eceunur@yahoo.com [Department of Energy Systems Engineering, Bursa Technical University, Yildirim 16310, Bursa (Turkey)

2016-11-01

Fe{sub 3}O{sub 4} nanoparticles with ∼10 nm diameters were synthesized by an extremely low-cost, scalable and relatively biocompatible chemical co-precipitation method. Magnetic measurements revealed that Fe{sub 3}O{sub 4} nanoparticles have bifunctional superparamagnetic and ferromagnetic character with saturation magnetization (M{sub s}) values of 64 and 71 emu g{sup −1} at 298 K and 10 K, respectively. Pseudocapacitive Fe{sub 3}O{sub 4} nanoparticles were then integrated into hazelnut shells - an abundant agricultural biomass - by an energy efficient hydrothermal carbonization method. Presence of magnesium oxide (MgO) ceramic template or its precursor in the hydrothermal reactor allowed simultaneous introduction of pores into the composite structure. Hierarchically micro-mesoporous Fe{sub 3}O{sub 4}/C nanocomposite possesses a high specific surface area of 344 m{sup 2} g{sup −1}. Electrochemical properties of Fe{sub 3}O{sub 4}/C nanocomposite were investigated by cyclic voltammetry and galvanostatic charge-discharge measurements in a conventional three-electrode cell. The Fe{sub 3}O{sub 4}/C nanocomposite is able to operate in a large negative potential window in 1 M Na{sub 2}SO{sub 4} aqueous electrolyte (−1.2–0 V vs. Ag/AgCl). Synergistic effect of the Fe{sub 3}O{sub 4} and carbon leads to enhanced specific capacitance, rate capability and cyclability making Fe{sub 3}O{sub 4}/C nanocomposite a very promising negative electrode material for asymmetric supercapacitors. - Highlights: • Fe{sub 3}O{sub 4} (magnetite) particles with ∼10 nm dia. were prepared by a facile chemical co-precipitation. • Fe{sub 3}O{sub 4} nanospheres are superparamagnetic at 298K with high saturation magnetization of 64 emu g{sup −1}. • Porous Fe{sub 3}O{sub 4}/C nanocomposite was also prepared by a green HTC method combined with MgO templating. • Electrochemical properties of Fe{sub 3}O{sub 4}/C were studied in 1 M Na{sub 2}SO{sub 4} (between −1.2 and 0 V vs. Ag

Structural, optical, and magnetic properties of Fe doped In{sub 2}O{sub 3} powders

Energy Technology Data Exchange (ETDEWEB)

Krishna, N. Sai [Thin Films Laboratory, School of Advanced Sciences, VIT University, Vellore 632 014, Tamilnadu (India); Kaleemulla, S., E-mail: skaleemulla@gmail.com [Thin Films Laboratory, School of Advanced Sciences, VIT University, Vellore 632 014, Tamilnadu (India); Amarendra, G. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamilnadu (India); UGC-DAE-CSR, Kalpakkam Node, Kokilamedu 603 104, Tamilnadu (India); Rao, N. Madhusudhana; Krishnamoorthi, C.; Kuppan, M.; Begam, M. Rigana [Thin Films Laboratory, School of Advanced Sciences, VIT University, Vellore 632 014, Tamilnadu (India); Reddy, D. Sreekantha [Department of Physics and Sungkyunkwan Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Omkaram, I. [Department of Electronics and Radio Engineering, Kyung Hee University, Yongin-si, Gyeonggi-do 446-701 (Korea, Republic of)

2015-01-15

Highlights: • Synthesis of Fe doped In{sub 2}O{sub 3} powders using a solid state reaction. • Characterization of the samples using XRD, UV–vis-NIR, FT-IR, and VSM. • All Fe doped In{sub 2}O{sub 3} powders exhibited the cubic structure of In{sub 2}O{sub 3}. • All the Fe doped In{sub 2}O{sub 3} samples exhibited room temperature ferromagnetism. - Abstract: Iron doped indium oxide dilute magnetic semiconductor (In{sub 1−x}Fe{sub x}){sub 2}O{sub 3} (x = 0.00, 0.03, 0.05, and 0.07) powders were synthesized by standard solid state reaction method followed by vacuum annealing. The effect of Fe concentration on structural, optical, and magnetic properties of the (In{sub 1−x}Fe{sub x}){sub 2}O{sub 3} powders have been systematically studied. X-ray diffraction patterns confirmed the polycrystalline cubic structure of all the samples. An optical band gap increases from 3.12 eV to 3.16 eV while Fe concentration varying from 0.03 to 0.07. Magnetic studies reveal that virgin/undoped In{sub 2}O{sub 3} is diamagnetic. However, all the Fe-doped In{sub 2}O{sub 3} samples are ferromagnetic. The saturation magnetization (M{sub s}) of ferromagnetic (In{sub 1−x}Fe{sub x}){sub 2}O{sub 3} (x = 0.03, 0.05, and 0.07) samples increases from 11.56 memu/g to 148.64 memu/g with x = 0.03–0.07. The observed ferromagnetism in these samples was attributed to magnetic nature of the dopant (Fe) as well as defects created in the samples during vacuum annealing.
La{sub 2}O{sub 3}-reinforced W and W-V alloys produced by hot isostatic pressing

Energy Technology Data Exchange (ETDEWEB)

Munoz, A., E-mail: angel.munoz@uc3m.es [Departamento de Fisica, Universidad Carlos III de Madrid, 28911 Leganes (Spain); Monge, M.A., E-mail: mmonge@fis.uc3m.es [Departamento de Fisica, Universidad Carlos III de Madrid, 28911 Leganes (Spain); Savoini, B., E-mail: bsavoi@fis.uc3m.es [Departamento de Fisica, Universidad Carlos III de Madrid, 28911 Leganes (Spain); Rabanal, M.E., E-mail: eugenia@ing.uc3m.es [Departamento de Ciencia e Ingenieria de Materiales e Ingenieria Quimica, Universidad Carlos III de Madrid, 28911 Leganes (Spain); Garces, G., E-mail: ggarces@cenim.csic.es [Centro Nacional de Investigaciones Melaturgicas, CENIM, 28040 Madrid (Spain); Pareja, R., E-mail: rpp@fis.uc3m.es [Departamento de Fisica, Universidad Carlos III de Madrid, 28911 Leganes (Spain)

2011-10-01

W and W-V alloys reinforced with La{sub 2}O{sub 3} particles have been produced by MA and subsequent HIP at 1573 K and 195 MPa. The microstructure of the consolidated alloys has been characterized by scanning electron microscopy, energy dispersive spectroscopy analyses and X-ray diffraction. The mechanical properties were studied by nanoindentation measurements. The results show that practically full dense billets of W-V, W-V-La{sub 2}O{sub 3} and W-La{sub 2}O{sub 3} alloys can be produced. The microstructure analysis has shown that islands of V are present in W-V and W-V-1La{sub 2}O{sub 3} alloys. In W-1La{sub 2}O{sub 3} islands of La{sub 2}O{sub 3} are also present. The nanohardness of the W matrix increases with the addition of V, while decreases with the addition of La{sub 2}O{sub 3}.
Nanostructured Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O heterojunction photoelectrode for efficient hydrogen production

Energy Technology Data Exchange (ETDEWEB)

Sharma, Dipika; Upadhyay, Sumant; Verma, Anuradha [Department of Chemistry, Dayalbagh Educational Institute, Agra-282 110 India (India); Satsangi, Vibha R. [Department of Physics Computer Sciences, Dayalbagh Educational Institute, Agra-282 110 India (India); Shrivastav, Rohit [Department of Chemistry, Dayalbagh Educational Institute, Agra-282 110 India (India); Dass, Sahab, E-mail: drsahabdas@gmail.com [Department of Chemistry, Dayalbagh Educational Institute, Agra-282 110 India (India)

2015-01-01

Nanostructured thin films of pristine Fe{sub 2}O{sub 3}, Ti-doped Fe{sub 2}O{sub 3}, Cu{sub 2}O, and Fe{sub 2}O{sub 3}/Cu{sub 2}O, and Ti-doped Fe{sub 2}O{sub 3}/Cu{sub 2}O heterojunction were deposited on tin-doped indium oxide (Sn:In{sub 2}O{sub 3}) glass substrate using spray pyrolysis method. Ti doping is done to improve photoelectric conversion efficiency and electrical conductivity of hematite thin films. Further enhanced photocurrent is achieved for Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O heterojunction electrodes. All samples were characterized using X-ray diffractometry, scanning electron microscopy, atomic force microscopy, and UV-Vis spectrometry. Photoelectrochemical properties were also investigated in a three-electrode cell system. UV-Vis absorption spectrum for pristine Fe{sub 2}O{sub 3}, Ti-Fe{sub 2}O{sub 3}, Cu{sub 2}O, Fe{sub 2}O{sub 3}/Cu{sub 2}O, and Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O heterojunction thin films exhibited absorption in visible region. Nanostructured thin films as prepared were used as photoelectrode in the photoelectrochemical cell for water splitting reaction. Maximum photocurrent density of 2.60 mA/cm{sup 2} at 0.95 V/SCE was exhibited by 454 nm thick Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O heterojunction photoelectrode. Increased photocurrent density and enhanced incident photon-to-electron conversion efficiency, offered by the heterojunction thin films may be attributed to improved conductivity and efficient separation of the photogenerated charge carriers at the Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O interface. - Highlights: • Heterojunction thin films were deposited using spray pyrolysis techniques. • Titanium doping in Fe{sub 2}O{sub 3} played a significant role in PEC response. • Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O heterojunction shows the absorption in visible range. • Improved charge separation and enhanced PEC response were achieved in Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O.
Magnetotransport in La{sub 0.7}Sr{sub 0.3}MnO{sub 3}/CuCr{sub 2}O{sub 4}/Fe{sub 3}O{sub 4} magnetic junctions

Energy Technology Data Exchange (ETDEWEB)

Iwata-Harms, Jodi M.; Suzuki, Yuri [Department of Materials Science and Engineering, University of California, Berkeley, California 94720 (United States); Department of Applied Physics and Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305 (United States); Chopdekar, Rajesh V. [Department of Materials Science and Engineering, University of California, Berkeley, California 94720 (United States); School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853 (United States); Wong, Franklin J. [Department of Materials Science and Engineering, University of California, Berkeley, California 94720 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Nelson-Cheeseman, Brittany B. [Department of Materials Science and Engineering, University of California, Berkeley, California 94720 (United States); Jenkins, Catherine A.; Arenholz, Elke [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2015-01-05

We demonstrate distinct magnetic and resistive switching with junction magnetoresistance up to −6% in magnetic tunnel junctions with a CuCr{sub 2}O{sub 4} barrier. Junction magnetoresistance is inversely related to barrier thickness and reveals a maximum at a finite applied bias that converges to zero bias at low temperatures for all barrier thicknesses. The non-monotonic bias dependence is attributed to a charge gap from the Fe{sub 3}O{sub 4} electrode and possible spin filtering from the spin-split conduction band of the ferrimagnetic CuCr{sub 2}O{sub 4} barrier.
Diffusion Monte Carlo studies of MB-pol (H{sub 2}O){sub 2−6} and (D{sub 2}O){sub 2−6} clusters: Structures and binding energies

Energy Technology Data Exchange (ETDEWEB)

Mallory, Joel D.; Mandelshtam, Vladimir A. [Department of Chemistry, University of California, Irvine, California 92697 (United States)

2016-08-14

We employ the diffusion Monte Carlo (DMC) method in conjunction with the recently developed, ab initio-based MB-pol potential energy surface to characterize the ground states of small (H{sub 2}O){sub 2−6} clusters and their deuterated isotopomers. Observables, other than the ground state energies, are computed using the descendant weighting approach. Among those are various spatial correlation functions and relative isomer fractions. Interestingly, the ground states of all clusters considered in this study, except for the dimer, are delocalized over at least two conformations that differ by the orientation of one or more water monomers with the relative isomer populations being sensitive to the isotope substitution. Most remarkably, the ground state of the (H{sub 2}O){sub 6} hexamer is represented by four distinct cage structures, while that of (D{sub 2}O){sub 6} is dominated by the prism, i.e., the global minimum geometry, with a very small contribution from a prism-book geometry. In addition, for (H{sub 2}O){sub 6} and (D{sub 2}O){sub 6}, we performed DMC calculations to compute the ground states constrained to the cage and prism geometries. These calculations compared results for three different potentials, MB-pol, TTM3/F, and q-TIP4P/F.
Synthesis of NiCo{sub 2}O{sub 4} nanostructures with different morphologies for the removal of methyl orange

Energy Technology Data Exchange (ETDEWEB)

Tian, Yaxi; Li, Haizhen; Ruan, Zhongyuan; Cui, Guijia; Yan, Shiqiang, E-mail: yansq@lzu.edu.cn

2017-01-30

Highlights: • Magnetic materials NiCo{sub 2}O{sub 4} with six different morphologies were successfully synthesized by a facile method. • Adsorption capacity strongly depends on the morphology. • It could be easily recovered from solution. - Abstract: Aiming to investigate the adsorption removal performance of NiCo{sub 2}O{sub 4} as water purification adsorbents, magnetic materials NiCo{sub 2}O{sub 4} with six different morphologies were successfully synthesized by a facile method. NiCo{sub 2}O{sub 4} with six different morphologies were characterized by scanning electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction, N{sub 2} adsorption-desorption, vibrating sample magnetometry and X-ray energy dispersive spectrometry. In this study, we mainly explored the effect of specific surface area, pore volume and pore size on the performance for the removal of methyl orange, and the adsorption capacity followed an order of (b) NiCo{sub 2}O{sub 4} nanorods > (e) balsam-like NiCo{sub 2}O{sub 4} > (f) rose-like NiCo{sub 2}O{sub 4} > (d) NiCo{sub 2}O{sub 4} nanoribbons > (a) NiCo{sub 2}O{sub 4} flowerlike nanostructures > (c) dandelion-like NiCo{sub 2}O{sub 4} spheres. The results indicated that NiCo{sub 2}O{sub 4} nanorods exhibited better adsorption performance. The reasons for the excellent adsorption capacity of NiCo{sub 2}O{sub 4} nanorods were also discussed in depth by analyzing scale and surface characteristics. Besides, NiCo{sub 2}O{sub 4} could be easily recovered from solution, which may avoid potential secondary pollution. Moreover, adsorption kinetics, the influence of pH and adsorption mechanism were comprehensively investigated. This finding indicated that NiCo{sub 2}O{sub 4} were promising adsorbents for water purification.
Luminescence dosemeter of the Al{sub 2}O{sub 3}:Er,Yb

Energy Technology Data Exchange (ETDEWEB)

Goncalves, Katia A.; Ventieri, Alexandre; Bitencourt, Jose F.S. [Universidade de Sao Paulo (EP/USP), SP (Brazil). Escola Politecnica. Dept. de Engenharia Eletrica; Mittani, Juan C.R.; Tatumi, Sonia H. [Faculdade de Tecnologia de Sao Paulo (CEETEPS), SP (Brazil)

2011-07-01

The present work deals with the thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) properties of {alpha}-Al{sub 2}O{sub 3}: Er,Yb obtained by sol gel process. Nanocrystals formations composed by Er{sub 2}O{sub 3}, Yb{sub 2}O{sub 3} and Yb{sub 3}Al{sub 5}O{sub 12} were observed by TEM images, EDS, electron beam diffraction and RXD, located at the surface of the alumina grains. The sample codoped with 1mol% of Er and 2 mol% of Yb supplied the best results for TL and OSL responses. The growth of the intensity of dosimetric TL peak at 205 deg C was linear with gamma radiation doses and the same behavior was observed in OSL growth curve. The luminescence fading of the sample after a dose of 5 Gy was found initially for a period of 30 days and minimum detectable dose measured for TL was 60.78 mGy and for OSL was 13.09 mGy. (author)
Analysis of molecular species of triacylglycerols from vegetable oils containing fatty acids with non-methylene-interrupted double bonds, by HPLC in the silver-ion mode

Energy Technology Data Exchange (ETDEWEB)

Joh, Y.; Kim, S. [Dong A Univ., Pusan (Korea, Republic of)

1998-10-20

The possibilities for application of silver ion HPLC to analysis of the triacylglycerols containing conjugate trienoic acids and {Delta}{sup 5}-polymethylene-interrupted acids and proportions of triacylglycerol fractions obtained by silver-ion HPLC from the seed oil of Momordica charantia double bonds were examined, respectively. The triacylglycerols of seed oils containing conjugate trienoic acids such as {alpha}-eleostearic acid (C{sub 18:3 9c,11t,13t}) and punicic acid (C{sub 18:3} {sub 9c,11t,13c}) were resolved by silver-ion HPLC. Fractions were fractionated on the basis of the number and configuration of double bonds in the species, and the elution profile is quite different from that of the species comprising exclusively saturated and unsaturated fatty acids with methylene-interrupted double bonds ; for instance, the species (DT(c2)) composed of one dienoic acid and two conjugate trienoic acids eluted much earlier than the species (D{sub 2}T{sub c}) composed of two dienoic acids and one conjugate trienoic acid, in spite of having larger number of double bonds. This means that the interaction of conjugate double bonds with silver ions is weaker than that of methylene-interrupted double bonds, presumably because of the delocalization of {pi}-electrons in conjugate double bonds. In this instance, the strength of interaction of a conjugate trienoic double bond system with silver ions seemed to be between that of methylene-interrupted dienoic and monoenoic double bond systems. Triacylglycerols of the seeds of Ginkgo biloba have been resolved by HPLC in the silver-ion mode according to the number and position of double bonds. In this instance, the strength of interaction between the {pi}-electrons of double bonds in the fatty acyl residues and silver ions is in the order; C{sub 18:3{omega}3}>C(20:3){Delta}{sup 5,11,14}C{sub 18:3}{Delta}{sup 5,9,12}>= C{sub 18:2{omega}6}>C{sub 18:2}{Delta}{sup 5,9}>C{sub 18:1{omega}9}>C{sub 18:1ome= ga7}. 49 refs., 2 figs., 2 tabs.
Adsorption studies of Cd(II) onto Al{sub 2}O{sub 3}/Nb{sub 2}O{sub 5} mixed oxide dispersed on silica matrix and its on-line preconcentration and determination by flame atomic absorption spectrometry

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Mendonca Costa, Lucimara [Programa de Pos-Graduacao em Quimica da Universidade Federal de Alfenas, Rua Gabriel Monteiro da Silva, 700, Alfenas-MG, CEP 37130-000 (Brazil); Ribeiro, Emerson Schwingel [Instituto de Quimica, Universidade Federal do Rio de Janeiro, Rio de Janeiro-RJ, CEP 21941-909 (Brazil); Segatelli, Mariana Gava [Departamento de Quimica, Universidade Estadual de Londrina, Rod. Celso Garcia Cid, PR 445 Km 380, Campus Universitario, Londrina-PR, CEP 86051-990 (Brazil); Nascimento, Danielle Raphael do [Instituto de Quimica, Universidade Federal do Rio de Janeiro, Rio de Janeiro-RJ, CEP 21941-909 (Brazil); Midori de Oliveira, Fernanda [Departamento de Quimica, Universidade Estadual de Londrina, Rod. Celso Garcia Cid, PR 445 Km 380, Campus Universitario, Londrina-PR, CEP 86051-990 (Brazil); Tarley, Cesar Ricardo Teixeira, E-mail: tarley@uel.br [Programa de Pos-Graduacao em Quimica da Universidade Federal de Alfenas, Rua Gabriel Monteiro da Silva, 700, Alfenas-MG, CEP 37130-000 (Brazil); Departamento de Quimica, Universidade Estadual de Londrina, Rod. Celso Garcia Cid, PR 445 Km 380, Campus Universitario, Londrina-PR, CEP 86051-990 (Brazil)

2011-05-15

The present study describes the adsorption characteristic of Cd(II) onto Nb{sub 2}O{sub 5}/Al{sub 2}O{sub 3} mixed oxide dispersed on silica matrix. The characterization of the adsorbent has been carried out by infrared spectroscopy (IR), scanning electronic microscopy (SEM), energy dispersive spectroscopy (EDS), energy dispersive X-ray fluorescence analysis (EDXRF) and specific surface area (S{sub BET}). From batch experiments, adsorption kinetic of Cd(II) was described by a pseudo-second-order kinetic model. The Langmuir linear isotherm fitted to the experimental adsorption isotherm very well, and the maximum adsorption capacity was found to be 17.88 mg g{sup -1}. Using the effective material, a method for Cd(II) preconcentration at trace level was developed. The method was based on on-line adsorption of Cd(II) onto SiO{sub 2}/Al{sub 2}O{sub 3}/Nb{sub 2}O{sub 5} at pH 8.64, in which the quantitative desorption occurs with 1.0 mol L{sup -1} hydrochloric acid towards FAAS detector. The experimental parameters related to the system were studied by means of multivariate analysis, using 2{sup 4} full factorial design and Doehlert matrix. The effect of SO{sub 4}{sup 2-}, Cu{sup 2+}, Zn{sup 2+} and Ni{sup 2+} foreign ions showed no interference at 1:100 analyte:interferent proportion. Under the most favorable experimental conditions, the preconcentration system provided a preconcentration factor of 18.4 times, consumption index of 1.08 mL, sample throughput of 14 h{sup -1}, concentration efficiency of 4.35 min{sup -1}, linear range from 5.0 up to 35.0 {mu}g L{sup -1} and limits of detection and quantification of 0.19 and 0.65 {mu}g L{sup -1} respectively. The feasibility of the proposed method for Cd(II) determination was assessed by analysis of water samples, cigarette sample and certified reference materials TORT-2 (Lobster hepatopancreas) and DOLT-4 (Dogfish liver).
Cobalt surface modification during γ-Fe{sub 2}O{sub 3} nanoparticle synthesis by chemical-induced transition

Energy Technology Data Exchange (ETDEWEB)

Li, Junming [School of Physical Science and Technology, Southwest University, Chongqing 400715 (China); Li, Jian, E-mail: aizhong@swu.edu.cn [School of Physical Science and Technology, Southwest University, Chongqing 400715 (China); Chen, Longlong; Lin, Yueqiang; Liu, Xiaodong; Gong, Xiaomin [School of Physical Science and Technology, Southwest University, Chongqing 400715 (China); Li, Decai [School of Mechanical and Control Engineering, Beijing Jiaotong University, Beijing 100044 (China)

2015-02-01

In the chemical-induced transition of FeCl{sub 2} solution, the FeOOH/Mg(OH){sub 2} precursor was transformed into spinel structured γ-Fe{sub 2}O{sub 3} crystallites, coated with a FeCl{sub 3}·6H{sub 2}O layer. CoCl{sub 2} surface modified γ-Fe{sub 2}O{sub 3} nanoparticles were prepared by adding Co(NO{sub 3}){sub 2} during the synthesis. CoFe{sub 2}O{sub 4} modified γ-Fe{sub 2}O{sub 3} nanoparticles were prepared by adding NaOH during the surface modification with Co(NO{sub 3}){sub 2}. The CoFe{sub 2}O{sub 4} layer grew epitaxially on the γ-Fe{sub 2}O{sub 3} crystallite to form a composite crystallite, which was coated by CoCl{sub 2}·6H{sub 2}O. The composite could not be distinguished using X-ray diffraction or transmission electron microscopy, since CoFe{sub 2}O{sub 4} and γ-Fe{sub 2}O{sub 3} possess similar spinel structures and lattice constants. X-ray photoelectron spectroscopy was used to distinguish them. The saturation magnetization and coercivity of the spinel structured γ-Fe{sub 2}O{sub 3}-based nanoparticles were related to the grain size. - Highlights: • γ-Fe{sub 2}O{sub 3} nanoparticles were synthesized by chemical induced transition. • CoCl{sub 2} modified nanoparticles were prepared by additional Co(NO{sub 3}){sub 2} during synthesization. • CoFe{sub 2}O{sub 4} modified nanoparticles were prepared by additional Co(NO{sub 3}){sub 2} and NaOH. • The magnetism of the nanoparticles is related to the grain size.
Water isotopic characterization of hypersaline formation of a petroleum field Reconcavo basin, Brazil; Caracterizacao isotopica de aguas de formacao hipersalinas de um campo de petroleo da Bacia do Reconcavo, Brasil

Energy Technology Data Exchange (ETDEWEB)

Teles, Danilo Ribeiro de Sa; Azevedo, Antonio Expedito Gomes de, E-mail: danilosateles@yahoo.com.br, E-mail: expedito@ufba.br [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Fisica. Centro de Pesquisa em Geofisica e Geologia; Santos, Christian Pereira Lopes dos, E-mail: cplsgs@gmail.com [Instituto Federal Baiano, Salvador, BA (Brazil)

2010-04-15

Formation water is the water present in reservoir rock pores, produced together with petroleum. Usually it is hyper saline with concentrations that can be higher than 250 g/l of dissolved solids. The concentration of the dissolved elements and the isotopic composition of the water and of some of the dissolved elements can be excellent tracers to study the dynamic of underground fluid flux, the mixing of distinct sources and the origin of salinization of these waters. This work reports the isotopic composition ({delta}{sup 2}H , {delta}{sup 18}O) and electrical conductivity (EC) of formation waters from 10 wells of a petroleum field of the Reconcavo Basin, looking for their evolution, interaction with the minerals and rocks and reservoir interconnection. The samples have electric conductivity ranging from 84 to 137 mS/cm, with conductivity increasing with depth of production zone. It is observed an enrichment of deuterium and oxygen-18 with the depth of production zone, probably due to water-rock interactions that were probably increased by higher temperatures of the deeper levels and longer residence times. The samples from the production zone between 1450 to 1520 m, drained by 7 of the 10 wells sampled, show a small range in isotopic composition and in electric conductivity, indicating homogeneity in this level of the reservoir. In the shallow level of 450 m the values of {delta}{sup 2}H , {delta}{sup 18}O and EC are lower, with isotopic composition similar to the oceanic water, possibly representing the original water that entered the reservoir during the sedimentation of the basin. (author)
Cubic-tetragonal transformation and magnetic properties in copper ferrites with excess Fe/sub 2/O/sub 3/

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Sugimoto, M [Saitama Univ., Urawa (Japan)

1977-01-01

Measurements have been performed of cubic-tetragonal transition temperatures and magnetic properties on a set of those samples of the binary system CuO-Fe/sub 2/O/sub 3/ which contain Fe/sub 2/O/sub 3/ more than stoichiometric CuFe/sub 2/O/sub 4/. A marked magnetic hardening was observed on a sample of 40CuO.60Fe/sub 2/O/sub 3/ which has been verified, through the X-ray analyses and measurements of Moessbauer spectra, to result from the precipitation of ..cap alpha..-Fe/sub 2/O/sub 3/ taking place during annealing.
Novel fungus-Fe{sub 3}O{sub 4} bio-nanocomposites as high performance adsorbents for the removal of radionuclides

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Ding, Congcong [Institute of Plasma Physics, Chinese Academy of Science, P.O. Box 1126, Hefei 230031 (China); University of Science and Technology of China, Hefei 230000 (China); Cheng, Wencai [Institute of Plasma Physics, Chinese Academy of Science, P.O. Box 1126, Hefei 230031 (China); Sun, Yubing, E-mail: sunyb@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Science, P.O. Box 1126, Hefei 230031 (China); School for Radiological and Interdisciplinary Sciences (RAD-X), Soochow University and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, 215123 Suzhou (China); School of Environment and Chemical Engineering, North China Electric Power University, Beijing 102206 (China); Wang, Xiangke, E-mail: xkwang@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Science, P.O. Box 1126, Hefei 230031 (China); School for Radiological and Interdisciplinary Sciences (RAD-X), Soochow University and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, 215123 Suzhou (China); School of Environment and Chemical Engineering, North China Electric Power University, Beijing 102206 (China); Faculty of Engineering, King Abdulaziz University, Jeddah 21589 (Saudi Arabia)

2015-09-15

Highlights: • Fungus was used as a template for the assembly of nano-Fe{sub 3}O{sub 4}. • Fungal template directed the nano-Fe{sub 3}O{sub 4} structure from the micro-scale level. • Fungal template enhanced the dispersity and stability of nano-Fe{sub 3}O{sub 4}. • Fungus-Fe{sub 3}O{sub 4} exhibited high sorption capacity for Sr(II), Th(IV) and U(VI). • Fungus-Fe{sub 3}O{sub 4} possessed satisfactory regeneration performance and reusability. - Abstract: The bio-nanocomposites of fungus-Fe{sub 3}O{sub 4} were successfully synthesized using a low-cost self-assembly technique. SEM images showed uniform decoration of nano-Fe{sub 3}O{sub 4} particles on fungus surface. The FTIR analysis indicated that nano-Fe{sub 3}O{sub 4} was combined to the fungus surface by chemical bonds. The sorption ability of fungus-Fe{sub 3}O{sub 4} toward Sr(II), Th(IV) and U(VI) was evaluated by batch techniques. Radionuclide sorption on fungus-Fe{sub 3}O{sub 4} was independent of ionic strength, indicating that inner-sphere surface complexion dominated their sorption. XPS analysis indicated that the inner-sphere radionuclide complexes were formed by mainly bonding with oxygen-containing functional groups (i.e., alcohol, acetal and carboxyl) of fungus-Fe{sub 3}O{sub 4}. The maximum sorption capacities of fungus-Fe{sub 3}O{sub 4} calculated from Langmuir isotherm model were 100.9, 223.9 and 280.8 mg/g for Sr(II) and U(VI) at pH 5.0, and Th(IV) at pH 3.0, respectively, at 303 K. Fungus-Fe{sub 3}O{sub 4} also exhibited excellent regeneration performance for the preconcentration of radionuclides. The calculated thermodynamic parameters showed that the sorption of radionuclides on fungus-Fe{sub 3}O{sub 4} was a spontaneous and endothermic process. The findings herein highlight the novel synthesis method of fungus-Fe{sub 3}O{sub 4} and its high sorption ability for radionuclides.
Thermoluminescence studies of γ-irradiated Al{sub 2}O{sub 3}:Ce{sup 3+} phosphor

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Reddy, S. Satyanarayana [Physics R & D Center, PES Institute of Technology, BSK 3rd Stage, Bangalore 560085 (India); Nagabhushana, K.R., E-mail: bhushankr@gmail.com [Physics R & D Center, PES Institute of Technology, BSK 3rd Stage, Bangalore 560085 (India); Department of Physics, PES University, BSK 3rd Stage, Bangalore 560085 (India); Singh, Fouran [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110 067 (India)

2016-07-15

Pure and Ce{sup 3+} doped Al{sub 2}O{sub 3} phosphors were synthesized by solution combustion method. The synthesized samples were characterized by X-ray diffraction (XRD) and its shows α-phase of Al{sub 2}O{sub 3}. Crystallite size was estimated by Williamson–Hall (W–H) method and found to be 49, 59 and 84 nm for pure, 0.1 mol% and 1 mol% Ce{sup 3+} doped Al{sub 2}O{sub 3} respectively. Trace elemental analysis of undoped Al{sub 2}O{sub 3} shows impurities viz. Fe, Cr, Mn, Mg, Ti, etc. Photoluminescence (PL) spectra of Al{sub 2}O{sub 3}:Ce{sup 3+} shows emission at 367 nm and excitation peak at 273 nm, which are corresponding to {sup 5}D → {sup 4}F and {sup 4}F → {sup 5}D transitions respectively. PL intensity decreases with concentration up to 0.4 mol%, beyond this mol% PL intensity increases with doping concentration up to 2 mol%. Thermoluminescence (TL) studies of γ-rayed pure and Ce{sup 3+} doped Al{sub 2}O{sub 3} have been studied. Two well resolved TL glow peaks at 457.5 K and 622 K were observed in pure Al{sub 2}O{sub 3}. Additional glow peak at 566 K was observed in Al{sub 2}O{sub 3}:Ce{sup 3+}. Maximum TL intensity was observed for Al{sub 2}O{sub 3}:Ce{sup 3+} (0.1 mol%) beyond this TL intensity decreases with increasing Ce{sup 3+} concentration. Computerized glow curve deconvolution (CGCD) method was used to resolve the multiple peaks and to calculate TL kinetic parameters. Thermoluminescence emission (TLE) spectra of pure Al{sub 2}O{sub 3} glow peaks (457.5 K and 622 K) shows sharp emission at 694 nm and two small humps at 672 nm and 709 nm. The sharp peak at 696 nm corresponds to Cr{sup 3+} impurity of {sup 2}E{sub g} → {sup 4}A{sub 2g} transition of R lines and 713 nm hump is undoubtedly belongs to Cr{sup 3+} emission of near neighbor pairs. The emission at 672 nm is characteristic of Mn{sup 4+} impurity ions of {sup 2}E → {sup 4}A{sub 2} transition. TLE of Al{sub 2}O{sub 3}:Ce{sup 3+} (0.1 mol%) shows additional broad emission at 412 nm
A comparative study of dissolution of {alpha}-Fe{sub 2}O{sub 3} and {gamma}-Fe{sub 2}O{sub 3} in DCD formulations

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Ranganathan, S.; Raghavan, P.S.; Gopalan, R. [Madras Christian Coll. (India). Dept. of Chemistry; Srinivasan, M.P.; Narasimhan, S.V.

1998-12-31

The important corrosion products deposited on the surfaces of structural materials such as stainless steel in the primary coolant system of BWRs are haematite in the outer layers and ferrites such as magnetite, nickel ferrite, cobalt ferrite, etc., in the inner layers. Magnetite dissolution by 2, 6 Pyridinedicarboxylic acid (PDCA), Ethylenediaminetetraacetic acid (EDTA) and Nitrolotriacetic acid (NTA) showed that there is an optimum pH of dissolution for each ligand. The leaching of the metal ions from the oxides is controlled in part by reductive dissolution; this is due to the presence of Fe(II)-L complexes generated from the released Fe{sup 2+} ions. The addition of Fe(II)-L with the formulation greatly increases the rate of dissolution. In order to understand the role of Fe{sup 2+} arising from the spinel lattice of Fe{sub 3}O{sub 4} in aiding the dissolution of magnetite, it is appropriate to study the dissolution behaviour of the system like Fe{sub 2}O{sub 3} which is not containing any Fe{sup 2+} in the crystal lattice. The present study has been carried out with {alpha}-Fe{sub 2}O{sub 3} and {gamma}-Fe{sub 2}O{sub 3} in DCD formulation in the presence of ascorbic acid and with the addition of Fe(II)-L as a reductant. (author)
Electrodeposition of Fe{sub 2}O{sub 3} nanoparticles and its supercapacitive properties

Energy Technology Data Exchange (ETDEWEB)

Kadam, S. L., E-mail: snehal.kadam54@gmail.com; Padwal, P. M., E-mail: pal-soni279@yahoo.com; Mane, S. M., E-mail: manesagar99@gmail.com; Kulkarni, S. B., E-mail: sbk-physics@yahoo.com [Department of Physics, The Institute of Science, Madam Cama Road, Mumbai-400032 (India)

2016-04-13

Fe{sub 2}O{sub 3} metal oxide nanoparticles are synthesized by electrodeposition method on stainless steel substrate. The crystal structure and surface morphological studies of the obtained metal oxide thin film are carried out by using X-ray diffraction (XRD) technique and Scanning Electron Microscopy (SEM) respectively. The electrochemical properties of Fe{sub 2}O{sub 3} thin film like Cyclic Voltammetry (CV), Galvonostatic Charge-Discharge (GCD) and Electrochemical Impedance Spectroscopy (EIS) are studied in a bath of 0.5 M Na{sub 2}SO{sub 4} as electrolyte. The observed specific capacitance shows improved values 135 Fg{sup −1} at 5 mVs{sup −1} scan rate. The electrochemical stability of Fe{sub 2}O{sub 3} electrode is investigated using cyclic voltammetry for 1000 cycles at a scan rate 50 mVs{sup −1}. The Fe{sub 2}O{sub 3} electrode exhibits superior cycling stability with only 4-5% capacitance loss after one thousand cycles. The values of specific power and specific energy of Fe{sub 2}O{sub 3} electrode obtained from Galvonostatic charge discharge studies are 2250 W.kg{sup −1} and 63.15 Wh.kg{sup −1} respectively at current density 1 A/g. From all the electrochemical properties of Fe{sub 2}O{sub 3} electrode, it indicates that it will be promising electrode material for supercapacitor application.
Magnetic and catalytic properties of inverse spinel CuFe{sub 2}O{sub 4} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Anandan, S., E-mail: sanand@nitt.edu [Nanomaterials and Solar Energy Conversion Lab, Department of Chemistry, National Institute of Technology, Trichy 620 015 (India); Department of Environmental Engineering and Science, Feng Chia University, Taichung 407, Taiwan (China); Selvamani, T.; Prasad, G. Guru [Nanomaterials and Solar Energy Conversion Lab, Department of Chemistry, National Institute of Technology, Trichy 620 015 (India); Asiri, A.M. [The Center of Excellence for Advanced Materials Research, King Abdulaziz University, P.O. Box 80203, Jeddah 21413 (Saudi Arabia); Wu, J.J., E-mail: jjwu@fcu.edu.tw [Department of Environmental Engineering and Science, Feng Chia University, Taichung 407, Taiwan (China)

2017-06-15

Highlights: • Copper ferrite (CuFe{sub 2}O{sub 4}) nanoparticles were synthesized via citrate-nitrate combustion method. • Spectroscopic information’s have found that CuFe{sub 2}O{sub 4} nanoparticles as an inverse spinel structure. • Magnetic study exhibits CuFe{sub 2}O{sub 4} nanoparticles have ferromagnetic behavior. • CuFe{sub 2}O{sub 4} nanoparticles employed for photocatalytic decolourisation of methylene blue under visible light irradiation. - Abstract: In this research, inverse spinel copper ferrite nanoparticles (CuFe{sub 2}O{sub 4} NPs) were synthesized via citrate-nitrate combustion method. The crystal structure, particle size, morphology and magnetic studies were investigated using various instrumental tools to illustrate the formation of the inverse spinel structure. Mossbauer spectrometry identified Fe is located both in the tetrahedral and octahedral site in the ratio (40:60) and the observed magnetic parameters values such as saturation magnetization (M{sub s} = 20.62 emu g{sup −1}), remnant magnetization (M{sub r} = 11.66 emu g{sup −1}) and coercivity (H{sub c} = 63.1 mTesla) revealed that the synthesized CuFe{sub 2}O{sub 4} NPs have a typical ferromagnetic behaviour. Also tested CuFe{sub 2}O{sub 4} nanoparticles as a photocatalyst for the decolourisation of methylene blue (MB) in the presence of peroxydisulphate as the oxidant.
Poly(o-phenylenediamine)/NiCoFe{sub 2}O{sub 4} nanocomposites: Synthesis, characterization, magnetic and dielectric properties

Energy Technology Data Exchange (ETDEWEB)

Kannapiran, Nagarajan [PG and Research Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India); Muthusamy, Athianna, E-mail: muthusrkv@gmail.com [PG and Research Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India); Chitra, Palanisamy; Anand, Siddeswaran [PG and Research Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India); Jayaprakash, Rajan [Nanotechnology Laboratory, Department of Physics, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India)

2017-02-01

In this study, poly(o-phenylenediamine) (PoPD)/NiCoFe{sub 2}O{sub 4} nanocomposites were synthesized by in-situ oxidative chemical polymerization method with different amount of NiCoFe{sub 2}O{sub 4} nanoparticles. The NiCoFe{sub 2}O{sub 4} nanoparticles were prepared by auto-combustion method. The structural, morphological, thermal properties of the synthesized PoPD/NiCoFe{sub 2}O{sub 4} nanocomposites were characterized by fourier transform infrared spectrum (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). Magnetic properties of NiCoFe{sub 2}O{sub 4} nanoparticles and PoPD/NiCoFe{sub 2}O{sub 4} nanocomposites were studied by vibrating sample magnetometer (VSM). The FTIR and XRD techniques were used to confirm the formation of PoPD/NiCoFe{sub 2}O{sub 4} nanocomposites. The average crystalline size of NiCoFe{sub 2}O{sub 4} nanoparticles and PoPD/NiCoFe{sub 2}O{sub 4} nanocomposites were calculated from XRD. From the SEM analysis, spherical morphology of the PoPD was confirmed. The TGA results showed that the NiCoFe{sub 2}O{sub 4} nanoparticles have improved the thermal stability of PoPD. Dielectric properties of PoPD/NiCoFe{sub 2}O{sub 4} nanocomposites at different temperatures have been carried in the frequency range 50 Hz to 5 MHz. - Highlights: • Auto-combustion method was support to achieve less particle size. • Green synthesis of PoPD and nanocomposites by in-situ oxidative chemical polymerization method. • For the first time, PoPD incorporated with NiCoFe{sub 2}O{sub 4} nanoparticles. • Ferrite content affects the magnetic and dielectric properties of the nanocomposites.
Radiation induced synthesis of In{sub 2}O{sub 3} nanoparticles - Part II: Synthesis of In{sub 2}O{sub 3} nanoparticles by thermal decomposition of un-irradiated and γ-irradiated indium acetylacetonate

Energy Technology Data Exchange (ETDEWEB)

Al-Resheedi, Ajayb Saud; Alhokbany, Norah Saad [Department of Chemistry, College of Science, King Saud University, KSU, (Saudi Arabia); Mahfouz, Refaat Mohammed, E-mail: rmhfouz@science.au.edu.eg [Chemistry Department, Faculty of Science, Assiut University, AUN, (Egypt)

2015-09-15

Pure cubic phase, In{sub 2}O{sub 3} nanoparticles with porous structure were synthesized by solid state thermal oxidation of un-irradiated and γ-irradiated indium acetyl acetonate in presence and absence of sodium dodecyl sulphate as surfactant. The as- synthesized In{sub 2}O{sub 3} nanoparticles were characterized by X-ray diffraction (XRD), fourier transformation infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transition electron microscopy (TEM) and thermogravimetry (TG). The shapes and morphologies of as- synthesized In{sub 2}O{sub 3} nanoparticles were highly affected by γ-irradiation of indium acetyl acetonate precursor and by addition of sodium dodecyl sulphate as surfactant. Calcination of un-irradiated indium acetyl acetonate precursor to 4 hours of 600 °C leads to the formation of spherical- shaped accumulative and merged In{sub 2}O{sub 3} nanoparticles with porous structure, whereas irregular porous architectures composed of pure In{sub 2}O{sub 3} nanoparticles were obtained by using γ-irradiated indium acetylacetonate precursor. The as- prepared In{sub 2}O{sub 3} nano products exhibit photoluminescence emission (PL) property and display thermal stability in a wide range of temperature (25-800 °C) which suggest possible applications in nanoscale optoelectronic devices. (author)
Microstructural characterization of Al{sub 2}O{sub 3}: Eu with dosimetric purposes; Cracterizacion microestructural de Al{sub 2}O{sub 3}: Eu con fines dosimetricos

Energy Technology Data Exchange (ETDEWEB)

Mendoza A, D.; Espinosa P, M.E.; Gonzalez M, P.R. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Rubio, E. [BUAP, Facultad de Ingenieria Quimica, 72570 Puebla (Mexico)

2004-07-01

In this work a microstructural analysis is presented, through Sem, EDS and XRD, of the alumina with Europium (Al{sub 2}O{sub 3}: Eu) synthesized by the sol gel method. According to those obtained results, a previous thermal treatment to 1000 C to the samples, induces the formation of the {gamma}-alumina phase for the samples that does not contain Eu; however when there is presence of this element, the {theta} alumina phase is obtained. Likewise, it was observed that the particle size is increased with the presence of Eu. When analyzing the thermoluminescent response (TL) induced by the gamma radiation, it was observed that the pure Al{sub 2}O{sub 3} presents an intense TL sign; while the Al{sub 2}O{sub 3}: Eu, the sign suffers a marked decrement. (Author)

SrBeB{sub 2}O{sub 5}: Growth, crystal structure and optical properties

Energy Technology Data Exchange (ETDEWEB)

Yao, Wenjiao; Wang, Xiaoshan [Center for Crystal Research and Development, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); University of the Chinese Academy of Sciences, Beijing 100049 (China); Huang, Hongwei [National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Xu, Tao; Jiang, Xingxing [Center for Crystal Research and Development, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); University of the Chinese Academy of Sciences, Beijing 100049 (China); Wang, Xiaoyang [Center for Crystal Research and Development, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Lin, Zheshuai, E-mail: zslin@mail.ipc.ac.cn [Center for Crystal Research and Development, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Chen, Chuangtian [Center for Crystal Research and Development, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

2014-04-01

Graphical abstract: The crystal displays a layered configuration along c axis with the wrinkled infinite (BeB{sub 2}O{sub 5}){sub ∞} layers. Display Omitted - Highlights: • A new beryllium borate SrBeB{sub 2}O{sub 5} was synthesized. • A layered structure (BeB{sub 2}O{sub 5}){sub ∞} was formed by BO{sub 3} triangles and B/BeO{sub 4} tetrahedrons. • SrBeB{sub 2}O{sub 5} has a very wide transparency range of wavelengths from 200 nm to 1800 nm. • A-site ions impact greatly on the structures of beryllium borates. - Abstract: A novel beryllium borate SrBeB{sub 2}O{sub 5} is discovered for the first time through traditional solid state reaction and high temperature solution method. The framework of the structure is composed by two-dimensional [BeB{sub 2}O{sub 5}] layers determined from single-crystal X-ray diffraction data. The further structural analysis of beryllium borates reveals that the arrangement of anionic groups attributes to the structural stability. Moreover, the influences of the A-site cations on the structural features of fundamental building blocks in the alkaline or alkaline earth beryllium borates are discussed. The UV–Vis–NIR diffuse-reflectance pattern reveals that this compound has a very wide transparency range of wavelengths down to 200 nm. In addition, the properties of SrBeB{sub 2}O{sub 5} were also characterized by powder X-ray diffraction, differential scanning calorimetry, and IR spectroscopy.
Structural and optical characterization of In{sub 2}O{sub 3}/PANI nanocomposite prepared by in-situ polymerization

Energy Technology Data Exchange (ETDEWEB)

Janeoo, Shashi; Sharma, Mamta, E-mail: mamta.phy85@gmail.com; Goswamy, J. [Department of Applied Sciences (Physics), UIET, Panjab University, Chandigarh-160 014 (India); Singh, Gurinder [Department of Applied Sciences (Physics), UIET, PUSSGSRC, Hoshiarpur (Punjab) (India)

2016-05-23

Polyaniline-indium oxide (In{sub 2}O{sub 3}/PANI) nanocomposite have been prepared by in-situ polymerization of aniline and as-synthesized In{sub 2}O{sub 3} nanoparticles. X-ray diffraction (XRD), Transmission electron microscopy (TEM), Fourier transformation infrared (FTIR) and UV/Vis spectroscopy techniques are used to investigate the structural and optical properties of In{sub 2}O{sub 3}/PANI nanocomposite. TEM analysis shows In{sub 2}O{sub 3} nanoparticles are embedded in PANI nanofibers. FTIR spectra show the good interactions between PANI nanofibers and In{sub 2}O{sub 3} nanoparticles. The band gap and electronic transitions in In{sub 2}O{sub 3}/PANI nanocomposite is determined by using UV/Vis spectra.
One step synthesis of Bi@Bi{sub 2}O{sub 3}@carboxylate-rich carbon spheres with enhanced photocatalytic performance

Energy Technology Data Exchange (ETDEWEB)

Qu, Lingling [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China); Luo, Zhijun, E-mail: lzj@ujs.edu.cn [School of the Environment, Jiangsu University, Zhenjiang 212013 (China); State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210093 (China); Tang, Chao [Maple Leaf International High School, Zhenjiang 212013 (China)

2013-11-15

Graphical abstract: Functional groups of sodium gluconate play synergetic roles in the formation of Bi@Bi{sub 2}O{sub 3}@carboxylate-rich carbon core–shell nanosturctures (Bi@Bi{sub 2}O{sub 3}@CRCSs). Bi@Bi{sub 2}O{sub 3}@CRCSs exhibits significant enhanced photocatalytic activity under visible light irradiation. - Highlights: • One step synthesis of Bi@Bi{sub 2}O{sub 3}@carboxylate-rich carbon spheres. • Functional groups of sodium gluconate play synergetic roles in the formation of Bi@Bi{sub 2}O{sub 3}@CRCSs. • Bi@Bi{sub 2}O{sub 3}@CRCSs exhibits enhanced photocatalytic activity under visible light irradiation. - Abstract: Bi@Bi{sub 2}O{sub 3}@carboxylate-rich carbon core-shell nanosturctures (Bi@Bi{sub 2}O{sub 3}@CRCSs) have been synthesized via a one-step method. The core–shell nanosturctures of the as-prepared samples were confirmed by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and Raman spectroscopy. The formation of Bi@Bi{sub 2}O{sub 3}@CRCSs core–shell nanosturctures should attribute to the synergetic roles of different functional groups of sodium gluconate. Bi@Bi{sub 2}O{sub 3}@CRCSs exhibits significant enhanced photocatalytic activity under visible light irradiation (λ > 420 nm) and shows an O{sub 2}-dependent feature. According to trapping experiments of radicals and holes, hydroxyl radicals were not the main active oxidative species in the photocatalytic degradation of MB, but O{sub 2}·{sup −} are the main active oxidative species.
The influence of magnetic interactions and shape anisotropy on the alignment and assembly of BaFe{sub 12}O{sub 19} and Er{sub 2}O{sub 3} nanoplates

Energy Technology Data Exchange (ETDEWEB)

Lisjak, Darja, E-mail: darja.lisjak@ijs.si

2014-11-14

Magnetically anisotropic material with useful properties can be obtained when the barium ferrite (BaFe{sub 12}O{sub 19}) plates are aligned in a single plane. We studied the influence of the magnetic forces and the shape anisotropy on the alignment of barium ferrite nanoparticles. Nanoplates with diameters of 10–350 nm and diameter-to-thickness ratios of 3–30 were synthesized hydrothermally and stabilized in 1-butanol with dodecylbenzene sulphonic acid. The nanoplates were then deposited from the suspension on gold-coated substrates and dried with or without an applied magnetic field. In both cases the nanoplates aligned preferentially in the plane of the substrate, as evidenced by the scanning electron microscopy observations. To compare the influence of the magnetic field and the magnetic dipole–dipole interactions with that of the nanoparticle shape anisotropy, the alignment of paramagnetic erbium oxide (Er{sub 2}O{sub 3}) nanoplates was also studied. A lower degree of alignment was obtained with the erbium oxide than with the barium ferrite nanoplates. Barium ferrite films with a minimum orientation of 90% were prepared from the deposits after sintering at 1150 °C for 5 h. A comparable alignment of the erbium oxide films was induced hydrodynamically during the electrophoretic deposition. - Highlights: • Aligned deposits from BaFe{sub 12}O{sub 19} and Er{sub 2}O{sub 3} were prepared. • The magnetic interactions prevail over the shape anisotropy effect. • The alignment of the BaFe{sub 12}O{sub 19} nanoplates was obtained by drying a suspension. • The alignment of Er{sub 2}O{sub 3} nanoplates was obtained only by electrophoretic deposition.
Characterization and study of dielectric and electrical properties of CaBi4Ti4O{sub 15} (CBT) added with Bi{sub 2}O{sub 3}; Caracterizacao e estudo das propriedades eletricas e dieletricas do CaBi{sub 4}Ti{sub 4}O{sub 15} (CBT) adicionado com Bi{sub 2}O{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Freitas, D.B.; Campos Filho, M.C.; Sales, J.C.; Silva, P.M.O.; Sombra, A.S. [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil)

2011-07-01

The ceramic perovskite CaBi{sub 4}Ti{sub 4}O{sub 15} (CBT) of space group A21am, Aurivillius family with deficiency A{sub 5}B{sub 4}O{sub 15} cation has been prepared by solid state method in a planetary ball mill of high energy. The reagents samples were ground and calcined and then added with Bi{sub 2}O{sub 3} (2% wt.) This work aims to characterize by X-ray diffraction to study the electrical properties and dielectric properties of (CBT). The x-ray diffraction revealed the formation of single orthorhombic phase. As for the dielectric properties (dielectric constant and dielectric loss) were measured at 30 deg C to 450 deg C, through which can be verified the presence of thermally activated processes. This phase has properties very relevant for possible use in capacitive devices, miniaturized filters, dielectric resonators antennas and oscillators. (author)
Thermal stability of SiO{sub 2}–B{sub 2}O{sub 3}–Al{sub 2}O{sub 3}–Na{sub 2}O–CaO glasses with high Nd{sub 2}O{sub 3} and MoO{sub 3} concentrations

Energy Technology Data Exchange (ETDEWEB)

Chouard, Nolwenn [Chimie ParisTech, PSL Research University, CNRS, Institut de Recherche de Chimie Paris (IRCP), 75005, Paris (France); Laboratoire d' Etude et Développement des Matrices de Conditionnement, CEA/DEN/DTCD/SECM, Marcoule, 30207, Bagnols-sur-Cèze (France); Caurant, Daniel, E-mail: daniel.caurant@chimie-paristech.fr [Chimie ParisTech, PSL Research University, CNRS, Institut de Recherche de Chimie Paris (IRCP), 75005, Paris (France); Majérus, Odile; Guezi-Hasni, Nadia [Chimie ParisTech, PSL Research University, CNRS, Institut de Recherche de Chimie Paris (IRCP), 75005, Paris (France); Dussossoy, Jean-Luc [Laboratoire des Matériaux et Procédés Actifs, CEA/DEN/DTCD/SECM/LMPA, Marcoule, 30207, Bagnols-sur-Cèze (France); Baddour-Hadjean, Rita; Pereira-Ramos, Jean-Pierre [Groupe Electrochimie et Spectroscopie des Matériaux (UMR CNRS 7182), Institut de Chimie et des Matériaux Paris-Est, 94320, Thiais (France)

2016-06-25

The incorporation of high MoO{sub 3} amounts in borosilicate glasses developed for the immobilization of radioactive waste may lead to the crystallization of Mo-rich phases that may induce a decrease of the long term performances of glasses. It is thus essential to understand their crystallization mechanisms and the possible effect of other abundant fission products present in the wastes (such as rare earths) in order to control or to avoid their formation during glass preparation. This paper presents a study, performed by X-ray diffraction, scanning electron microscopy, Raman and optical absorption spectroscopies of the stability as a function of the thermal treatment temperature T{sub C} of a simplified Mo-rich nuclear waste glass. The impact of the addition of a high amount of Nd{sub 2}O{sub 3} on the thermal stability of this glass is studied. For comparison, the thermal stability of a Nd{sub 2}O{sub 3}-rich glass without Mo is also presented. The crystallization range of all phases formed in these glasses (CaMoO{sub 4}, Na{sub 2}MoO{sub 4}, Ca{sub 2}Nd{sub 8}(SiO{sub 4}){sub 6}O{sub 2} (apatite)) and the evolution of their structure and microstructure as a function of T{sub C} are presented. The introduction of Nd{sub 2}O{sub 3} in the MoO{sub 3}-rich glass inhibits the crystallization of molybdates (increase of Mo solubility), as long as apatite does not form which suggests that [MoO{sub 4}]{sup 2-} entities and Nd{sup 3+} cations are close to each other in the glass structure. Besides, when a high density of apatite crystals form, for instance from glass surface, small Mo-rich partially crystallized globular heterogeneities are observed between these crystals that exacerbate the nucleation of new apatite crystals (nucleating effect). - Highlights: • Effect of MoO{sub 3} and Nd{sub 2}O{sub 3} separately or together on glass crystallization is studied. • The crystallization range of molybdates and apatite (Ca{sub 2}Nd{sub 8}(SiO{sub 4}){sub 6}O{sub 2}) was
Stemcell Information: SKIP000970 [SKIP Stemcell Database[Archive

Lifescience Database Archive (English)

Full Text Available SKIP000970 ... Diseased PDB1lox-21Puro-18 PDB1lox-21Puro-18 ... パーキンソン病 G20 Parkinson...ch Rudolf Jaenisch Available The Whitehead Institute The Whitehead Institute ... 19269371 10.1016/j.cell.2009.02.013 Parkinson
Production of thermoluminescent dosemeters based on MgB{sub 4}O{sub 7}: Dy and MgB{sub 4}O{sub 7}: Tm; Producao de dosimetros termoluminescentes a base de MgB{sub 4}O{sub 7}: Dy e MgB{sub 4}O{sub 7}: Tm

Energy Technology Data Exchange (ETDEWEB)

Souza, Luiza Freire de; Souza, Divanizia N., E-mail: luizaf25@hotmail.com, E-mail: divanizi@ufs.br [Universidade Federal de Sergipe (UFS), Sao Cristovao, SE (Brazil). Programa de Pos-Graduacao em Fisica

2013-07-01

The thermoluminescent dosimetry (TL) is a well-established technique for the detection of ionizing radiation in hospitals, clinics, and industrial establishments where there is the need to quantify the radiation. For this practice is require the use phosphors which are sensitive to radiation. Some phosphors are already commonly used in this practice, for example, TLD-100 (LiF: Mg, Ti), CaSO{sub 4}:Tm and CaSO{sub 4}:Dy. A compound that was most recently introduced in dosimetry and has many advantageous features to detect neutrons, electrons and gamma is the magnesium tetraborate (MgB{sub 4}O{sub 7}), but the undoped material is not good for dosimetry, since signal does not show satisfactory thermoluminescence. The present work presents the analysis of the compound MgB{sub 4}O{sub 7} when doped with rare earth elements, thulium (Tm) and dysprosium (Dy). The production of MgB{sub 4}O{sub 7}: Dy and MgB{sub 4}O{sub 7}: Tm occurred under acidic conditions. Following the process of crystal growth, several tests were made on phosphors produced to verify the quality of materials as TL dosimeter. Initially, was made the identification of the crystalline phases found in the material, using the technique of X-ray diffractometry, and then were evaluated and compared the TL emission curves of the crystals with two different types of dopants, to this, the samples were irradiated with different radiation sources: {sup 137}Cs (0,66 MeV), {sup 60}Co (1.25 MeV) and X-rays (0.41 MeV) and based on the results was evaluated the energy dependence of phosphors. Another characteristic analyzed, was the decay of TL signal for the material (fading). The results show that the material can be an excellent TL dosimeter when doped with rare earth elements Dy and Tm. (author)
Positron annihilation studies in the high-temperature superconductors YBa2Cu3Osub(7-x) and HoBa2Cu3Osub(7-x)

International Nuclear Information System (INIS)

Mandal, P.; Poddar, A.; Nambissan, P.M.G.; Choudhury, P.; Ghosh, B.; Sen, P.; Majumdar, C.K.

1988-01-01

In the high-Tsub(c) superconductors YBa 2 Cu 3 Osub(7-x) and HoBa 2 Cu 3 Osub(7-x) the Doppler-broadened positron annihilation lineshape parameter is studied as a function of temperature. Anomalies are detected around the transition temperature found by resistance measurements, giving indirect support for an electronic mechanism for superconductivity. The positron lifetimes in these compounds are measured at room temperature and are found to be similar. The origins of the several lifetimes found and their intensities are discussed. (author)
Syntheses, crystal structures and solid-state properties of the lanthanoid-containing nanoclusters [(Ln{sub 2}PW{sub 10}O{sub 38}){sub 4}(W{sub 3}O{sub 8})(OH){sub 4}(H{sub 2}O){sub 2}]{sup 26-}

Energy Technology Data Exchange (ETDEWEB)

Gupta, Rakesh; Saini, Mukesh Kumar; Hussain, Firasat [Department of Chemistry, University of Delhi (India)

2014-12-15

A series of lanthanoid-substituted polyoxometalates have been synthesized by a self-assembly process in potassium chloride solution by the reaction of dilacunary [P{sub 2}W{sub 19}O{sub 69}(H{sub 2}O)]{sup 14-} with mid- and late-lanthanoid Ln(NO{sub 3}){sub 3}.nH{sub 2}O salts leading to the formation of the tetrameric tungstophosphates [(Ln{sub 2}PW{sub 10}O{sub 38}){sub 4}(W{sub 3}O{sub 8})(OH){sub 4}(H{sub 2}O){sub 2}]{sup 26-} [Ln = Y{sup 3+} (1), Sm{sup 3+} (2), Eu{sup 3+} (3), Gd{sup 3+} (4), Tb{sup 3+} (5), Dy{sup 3+} (6), Ho{sup 3+} (7), Er{sup 3+} (8), Tm{sup 3+} (9), Yb{sup 3+} (10)]. The polyanions were isolated as potassium or mixed-alkali salts. Most of the compounds were characterized by single-crystal X-ray diffraction and various analytical techniques, such as FTIR, UV/Vis, {sup 31}P NMR and photoluminescence spectroscopy, magnetism, as well as thermogravimetric analysis. The FTIR spectra suggest that all the compounds are isomorphous. The crystal structures of these complexes consist of four A-[α-PW{sub 10}O{sub 36}]{sup 7-} units, each incorporating two Ln{sup III} ions to create four Keggin-like anions that further assemble with three additional tungstate units to form a tetramer species with C{sub 2} symmetry. The photoluminescent properties of 3a and 6a were investigated following photoexcitation at room temperature. The magnetic properties of 3a, 4a, 5a and 6a were investigated at room temperature, the complexes exhibiting paramagnetic behaviour. (Copyright copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Solid state reaction studies in Fe{sub 3}O{sub 4}–TiO{sub 2} system by diffusion couple method

Energy Technology Data Exchange (ETDEWEB)

Ren, Zhongshan [State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083 (China); School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Hu, Xiaojun, E-mail: huxiaojun@ustb.edu.cn [State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083 (China); School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Xue, Xiangxin [School of Materials and Metallurgy, Northeastern University, Shenyang 110006 (China); Chou, Kuochih [State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083 (China); School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083 (China)

2013-12-15

Highlights: •The solid state reactions of Fe2O3-TiO2 system was studied by the diffusion couple method. •Different products were formed by diffusion, and the FeTiO3 was more stable phase. •The inter-diffusion coefficients and diffusion activation energy were estimated. -- Abstract: The solid state reactions in Fe{sub 3}O{sub 4}–TiO{sub 2} system has been studied by diffusion couple experiments at 1323–1473 K, in which the oxygen partial pressure was controlled by the CO–CO{sub 2} gas mixture. The XRD analysis was used to confirm the phases of the inter-compound, and the concentration profiles were determined by electron probe microanalysis (EPMA). Based on the concentration profile of Ti, the inter-diffusion coefficients in Fe{sub 3}O{sub 4} phase, which were both temperature and concentration of Ti ions dependent, were calculated by the modified Boltzmann–Matano method. According to the relation between the thickness of diffusion layer and temperature, the diffusion coefficient of the Fe{sub 3}O{sub 4}–TiO{sub 2} system was obtained. According to the Arrhenius equation, the estimated diffusion activation energy was about 282.1 ± 18.8 kJ mol{sup −1}.
Ferromagnetic glass ceramics and glass fibers based on the composition of SiO{sub 2}-CaO-Al{sub 2}O{sub 3}-B{sub 2}O{sub 3}-Fe{sub 2}O{sub 3} glass system

Energy Technology Data Exchange (ETDEWEB)

Liu, Jianan, E-mail: lja@qlu.edu.cn; Zhu, Chaofeng; Zhang, Meimei; Zhang, Yanfei; Yang, Xuena

2017-03-15

Ferromagnetic glass-ceramics and glass fibers were obtained by the melt-method from the glass system SiO{sub 2}-CaO-Al{sub 2}O{sub 3}-B{sub 2}O{sub 3}-Fe{sub 2}O{sub 3} without performing any nucleation and crystallization heat treatments. Glass-ceramics and glass fibers were characterized by x-ray diffraction, scanning and transmission electron microscopy, magnetic measurements, and thermal expansion instrument. The influence of alumina content on the spontaneous crystallization of magnetite, magnetism properties and thermal expansion performances in glass were investigated. We examined the crystallization behavior of the glasses and found that the spontaneous crystallization capacity of magnetite and magnetism properties in base glass increases with increasing the content of alumina. The ferromagnetic glass fibers containing magnetite nano-crystals are also obtained. - Highlights: • Magnetite nano-crystals are formed spontaneously in the investigated glass systems. • The crystallization behavior of the glasses with the alumina content is examined. • Ferromagnetic glass fibers containing magnetite nano-crystals are obtained.
Surface passivation of Fe{sub 3}O{sub 4} nanoparticles with Al{sub 2}O{sub 3} via atomic layer deposition in a rotating fluidized bed reactor

Energy Technology Data Exchange (ETDEWEB)

Duan, Chen-Long; Deng, Zhang; Cao, Kun [State Key Laboratory of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei 430074 (China); Yin, Hong-Feng [Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201 (China); Shan, Bin [State Key Laboratory of Material Processing and Die and Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei 430074 (China); Chen, Rong, E-mail: rongchen@mail.hust.edu.cn [State Key Laboratory of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, School of Optical and Electronic Information, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei 430074 (China)

2016-07-15

Iron(II,III) oxide (Fe{sub 3}O{sub 4}) nanoparticles have shown great promise in many magnetic-related applications such as magnetic resonance imaging, hyperthermia treatment, and targeted drug delivery. Nevertheless, these nanoparticles are vulnerable to oxidation and magnetization loss under ambient conditions, and passivation is usually required for practical applications. In this work, a home-built rotating fluidized bed (RFB) atomic layer deposition (ALD) reactor was employed to form dense and uniform nanoscale Al{sub 2}O{sub 3} passivation layers on Fe{sub 3}O{sub 4} nanoparticles. The RFB reactor facilitated the precursor diffusion in the particle bed and intensified the dynamic dismantling of soft agglomerates, exposing every surface reactive site to precursor gases. With the aid of in situ mass spectroscopy, it was found that a thicker fluidization bed formed by larger amount of particles increased the residence time of precursors. The prolonged residence time allowed more thorough interactions between the particle surfaces and the precursor gas, resulting in an improvement of the precursor utilization from 78% to nearly 100%, even under a high precursor feeding rate. Uniform passivation layers around the magnetic cores were demonstrated by both transmission electron microscopy and the statistical analysis of Al mass concentrations. Individual particles were coated instead of the soft agglomerates, as was validated by the specific surface area analysis and particle size distribution. The results of thermogravimetric analysis suggested that 5 nm-thick ultrathin Al{sub 2}O{sub 3} coatings could effectively protect the Fe{sub 3}O{sub 4} nanoparticles from oxidation. The x-ray diffraction patterns also showed that the magnetic core crystallinity of such passivated nanoparticles could be well preserved under accelerated oxidation conditions. The precise thickness control via ALD maintained the saturation magnetization at 66.7 emu/g with a 5 nm-thick Al
Plasmonic Ag-pillared rectorite as catalyst for degradation of 2,4-DCP in the H{sub 2}O{sub 2}-containing system under visible light irradiation

Energy Technology Data Exchange (ETDEWEB)

Chen, Yunfang [School of Chemistry and Environment, South China Normal University, Guangzhou 510006, Guangdong (China); Fang, Jianzhang, E-mail: fangjzh@scnu.edu.cn [School of Chemistry and Environment, South China Normal University, Guangzhou 510006, Guangdong (China); Guangdong Technology Research Center for Ecological Management and Remediation of Urban Water System, Guangzhou 510006 (China); Lu, Shaoyou [Shenzhen Center for Disease Control and Prevention, Shenzhen 518055 (China); Wu, Yan; Chen, Dazhi; Huang, Liyan [Institute of Engineering Technology of Guangdong Province, Key Laboratory of Water Environmental Pollution Control of Guangdong Province, Guangzhou 510440 (China); Cheng, Cong; Ren, Lu; Zhu, Ximiao [School of Chemistry and Environment, South China Normal University, Guangzhou 510006, Guangdong (China); Fang, Zhanqiang [School of Chemistry and Environment, South China Normal University, Guangzhou 510006, Guangdong (China); Guangdong Technology Research Center for Ecological Management and Remediation of Urban Water System, Guangzhou 510006 (China)

2015-10-30

Highlights: • The Ag-R catalyst was synthesized via a novel thermal decomposition method. • Ag-R catalyst possessed the synergistic effects of SPR and adsorption capacity. • The degradation of 2,4-DCP was evaluated in Ag-R/H{sub 2}O{sub 2}/visible light system. - Abstract: This study aims at photocatalytic degradation of 2,4-DCP with the assistance of H{sub 2}O{sub 2} in aqueous solution by a composite catalyst of Ag-rectorite. The catalysts were prepared via a novel thermal decomposition method followed after the cation-exchange process. The synthesized nano-materials were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) surface analyzer, Ultraviolet–visible light (UV–vis) absorption spectra, field-emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM). The different mechanisms of degradation process with or without visible light irradiation were discussed, respectively. Moreover, the degradation efficiency of 2,4-DCP wastewater under Ag-rectorite/H{sub 2}O{sub 2}/visible light system was investigated by series of experiments, concerning on effects of major operation factors, such as H{sub 2}O{sub 2} dosage and the initial pH value. The highest degradation rate was observed when adding 0.18 mL H{sub 2}O{sub 2} into 50 mL 2,4-DCP solution, and the optimal pH value was 4 for the reaction. Afterwards, total organic carbon (TOC) experiments were carried out to evaluate the mineralization ratio of 2,4-DCP.
Single crystalline Co{sub 3}O{sub 4}: Synthesis and optical properties

Energy Technology Data Exchange (ETDEWEB)

Hosny, Nasser Mohammed, E-mail: Nasserh56@yahoo.com

2014-04-01

Crystals of Co{sub 3}O{sub 4} have been prepared from thermal decomposition of molecular precursors derived from salicylic acid and cobalt (II) acetate or chloride at 500 °C. A cubic phase Co{sub 3}O{sub 4} micro- and nanocrystals have been obtained. The as-synthesized products were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The images of electron microscopes showed octahedral crystals of Co{sub 3}O{sub 4}. The volume and polarizability of the optimized structures of molecular precursors have been calculated and related to the particle size. The optical band gap of the obtained crystals has been measured. The results indicated two optical band gaps with values 2.65 and 2.95 eV for (E{sub g1}) (E{sub g2}), respectively. - Highlights: • Synthesis of Co{sub 3}O{sub 4} nanocrystals by decomposition of cobalt salicylic acid precursor. • Characterization of the isolated nanocrystals by using XRD, SEM and HRTEM. • The optical band gap has been measured.
Sustained magnetization oscillations in polyaniline-Fe{sub 3}O{sub 4} nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Araújo, A. C. V. de [Unidade Acadêmica de Garanhuns, Universidade Federal Rural de Pernambuco, Recife, Pernambuco (Brazil); Rodrigues, A. R., E-mail: ricalde@df.ufpe.br; Machado, F. L. A.; Rezende, S. M. [Departamento de Física, Universidade Federal de Pernambuco, 50670-901 Recife, Pernambuco (Brazil); Azevedo, W. M. de [Departamento de Química Fundamental, Universidade Federal de Pernambuco, 50670-901 Recife, Pernambuco (Brazil)

2015-09-28

We report experiments with polyaniline-Fe{sub 3}O{sub 4} (PANI-Fe{sub 3}O{sub 4}) nanocomposites synthesized under several different conditions. With a reaction carried out at room temperature and assisted by intense ultra-violet (UV) irradiation, we observe sustained oscillations in the magnetization with a period of about 25 min. The oscillations are interpreted as the result of an oscillatory chemical reaction in which part of the Fe{sup +2} ions of magnetite, Fe{sub 3}O{sub 4}, are oxidized by the UV irradiation to form Fe{sup +3} so that a fraction of the magnetite content transforms into maghemite, γ-Fe{sub 2}O{sub 3}. Then, Fe{sup +3} ions at the nanoparticle surfaces are reduced and transformed back into Fe{sup +2}, when acting as an oxidizing agent for polyaniline in the polymerization process. Since maghemite has smaller magnetization than magnetite, the oscillating chemical reaction results in the oscillatory magnetization. The observations are interpreted with the Lotka-Volterra nonlinear coupled equations with parameters that can be adjusted to fit very well the experimental data.
Muon spin depolarization in Gd- and EuBa1Cu3O/sub x/

International Nuclear Information System (INIS)

Cooke, D.W.; Hutson, R.L.; Kwok, R.S.

1988-01-01

Positive muon spin rotation (μSR) measurements on Gd- and EuBa 2 Cu 3 O/sub x/ (x ∼ 7) have been conducted in the temperature interval 4-300K. For each sample, muons stop both at grain boundaries and within the superconducting grains. Measured magnetic field penetration depths are 1550 and 1900/angstrom/ for two specimens of GdBa 2 Cu 3 O/sub x/, and 1350/angstrom/ for EuBa 2 Cu 3 O/sub x/. 2 refs., 5 figs
Adsorption mechanism of magnetically separable Fe{sub 3}O{sub 4}/graphene oxide hybrids

Energy Technology Data Exchange (ETDEWEB)

Ouyang, Ke [Department of Chemical and Environment Engineering, Wuyi University, Jiangmen, Guangdong 529020 (China); Zhu, Chuanhe [Department of Civil, Construction and Environmental Engineering, Department of Chemical and Biological Engineering, Iowa State University, Ames, IA 50011 (United States); Zhao, Ya; Wang, Leichao [Department of Chemical and Environment Engineering, Wuyi University, Jiangmen, Guangdong 529020 (China); Xie, Shan, E-mail: wyuchemxs@126.com [Department of Chemical and Environment Engineering, Wuyi University, Jiangmen, Guangdong 529020 (China); Wang, Qun, E-mail: qunwang@iastate.edu [Department of Civil, Construction and Environmental Engineering, Department of Chemical and Biological Engineering, Iowa State University, Ames, IA 50011 (United States)

2015-11-15

Graphical abstract: A recyclable Fe{sub 3}O{sub 4}/graphene oxide (GO) magnetic hybrid was successfully synthesized via a facile one-pot polylol approach and exhibited an effective adsorption of BPA in aqueous solution. - Highlights: • Magnetically separable Fe{sub 3}O{sub 4}/GO hybrids were synthesized via a facile one-pot polylol approach. • The Fe{sub 3}O{sub 4}/GO hybrid could be easily recovered and met the need of magnetic separation, exhibiting excellent reproducibility and reusability. • The hybrids showed excellent adsorption ability for bisphenol A in aqueous solution. • The effect of pH value, temperature and coexisting ions on the adsorption was studied. • π–π interactions were postulated to be the primary mechanisms of adsorption of BPA on Fe{sub 3}O{sub 4}/GO hybrids. - Abstract: A reclaimable Fe{sub 3}O{sub 4}/graphene oxide (GO) magnetic hybrid was successfully synthesized via a facile one-pot polyol approach and employed as a recyclable adsorbent for Bisphenol A (BPA) in aqueous solutions. The maximum adsorption capacity (q{sub m}) of the Fe{sub 3}O{sub 4}/GO hybrid for BPA was 72.80 mg/g at 273 K. The kinetics of the adsorption process and the adsorption isotherm data were fitted using the Freundlich equation and a pseudo-second-order kinetic model. The results of the thermodynamic parameters ΔH°, ΔS° and ΔG° showed that the adsorption process was exothermic and spontaneous. Furthermore, the reusability of the samples was investigated, and the results indicated that the samples exhibited high stability. The magnetic characterization demonstrated that hybrids were superparamagnetic and could be recovered conveniently by magnetic separation. The strong π–π interaction was determined to be the predominant driving force behind the adsorption of BPA onto the Fe{sub 3}O{sub 4}/GO hybrid. Therefore, the Fe{sub 3}O{sub 4}/GO hybrid could be regarded as a potential adsorbent for wastewater treatment and purification processes.
High-pressure synthesis and crystal structure of In{sub 3}B{sub 5}O{sub 12}

Energy Technology Data Exchange (ETDEWEB)

Vitzthum, Daniela; Schauperl, Michael; Liedl, Klaus R.; Huppertz, Hubert [Univ. Innsbruck (Austria). Inst. fuer Allgemeine, Anorganische und Theoretische Chemie

2017-03-01

Orthorhombic In{sub 3}B{sub 5}O{sub 12} was synthesized in a Walker-type multianvil apparatus under high-pressure/high-temperature conditions of 12.2 GPa and 1500 C. Its structure is isotypic to the rare earth analogs RE{sub 3}B{sub 5}O{sub 12} (RE=Sc, Er-Lu). In the field of indium borate chemistry, In{sub 3}B{sub 5}O{sub 12} is the third known ternary indium borate besides InBO{sub 3} and InB{sub 5}O{sub 9}. The crystal structure of In{sub 3}B{sub 5}O{sub 12} has been determined via single-crystal X-ray diffraction data collected at room temperature. It crystallizes in the orthorhombic space group Pmna with the lattice parameters a=12.570(2), b=4.5141(4), c=12.397(2) Aa, and V=703.4(2) Aa{sup 3}. IR and Raman bands of In{sub 3}B{sub 5}O{sub 12} were theoretically determined and assigned to experimentally recorded spectra.
Mechanical dispersion of Y{sub 2}O{sub 3} nanoparticles in steel EUROFER 97: process and optimisation

Energy Technology Data Exchange (ETDEWEB)

Castro, V. de E-mail: mvcastro@fis.uc3m.es; Leguey, T.; Monge, M.A.; Munoz, A.; Pareja, R.; Amador, D.R.; Torralba, J.M.; Victoria, M

2003-11-01

The procedures followed to produce Y{sub 2}O{sub 3}-dispersed EUROFER 97 powder ready to be compacted and hot isostatic pressing processed are reported. An attrition mill has been used under controlled conditions. The compositional and microstructural characterization of the Y{sub 2}O{sub 3}/EUROFER powder along the different steps of the milling process has allowed optimising the processing conditions to obtain a nanosized Y{sub 2}O{sub 3} dispersion. TEM observations performed on Y{sub 2}O{sub 3}/EUROFER powder milled under these specific conditions reveal the presence of monoclinic Y{sub 2}O{sub 3} dispersoids having sizes around 10 nm in the ferrite/martensite matrix.

Measurement of the reaction {gamma}d {yields}pn{pi}{sup +}{pi}{sup -} at SAPHIR and investigation of the decay angular distribution of the {Delta}{sup ++}(1232) resonance; Messung der Reaktion {gamma}d {yields}pn{pi}{sup +}{pi}{sup -} an SAPHIR und Untersuchung der Zerfallswinkelverteilung der {Delta}{sup ++}(1232)-Resonanz

Energy Technology Data Exchange (ETDEWEB)

Schuetz, P.

1993-03-01

SAPHIR, a new experiment at the Bonn electron stretcher ring ELSA, started taking data in spring 1992. It was set up for the investigation of photon induced reactions with multiparticle final states. In the first part of this paper the special design of the target is described. It can be operated with liquefied hydrogen or deuterium and is placed in the middle of the central drift chamber. To project the surrounding chamber in case of a fracture of the target cell as safety system is installed. In addition two independent methods of monitoring the cell are procided. The first measurement was performed with a deuterium target at a photon energy range of E{sub {gamma}} = 500-700 MeV. In the second part of this paper first results of an analysis of the decay angular distribution of the {Delta}{sup ++}(1232) in the reaction {gamma}d {yields} n{Delta}{sup ++}{pi}{sup -} are presented. They are compared to old data from a hydrogen bubble chamber experiment and are discussed on the basis of a spectator model. (orig.) [Deutsch] Im Rahmen dieser Arbeit ist der Aufbau eines Fluessiggas-Targets beschrieben worden, das speziell fuer den Einsatz im SAPHIR-Detektor entwickelt worden ist. Es wurden Funktionen zur Ueberwachung der Targetzelle vorgestellt und ein Sicherheitssystem zum Schutz der zentralen Driftkammer, die das Target unmittelbar umgibt. Weiterhin ist in Simulationsrechnungen untersucht worden, welchen Einfluss die Konstruktion des Targetstreutopfes auf die Messung unterschiedlicher Reaktionen haben kann. Dabei sind bei 50% bis 70% der Ereignisse Treffer in den Aluminiumstuetzen des Targetstreutopfes aufgetreten. Diese starke Beeintraechtigung kann durch eine Neukonstruktion des Streutopfes und der Verwendung von z.B. Rohazell als Streutopffenster vermieden werden. Rohazell zeichnet sich durch eine hohe Festigkeit und grosse Strahlungslaenge aus. An der Neukonstruktion des Streutopfes wird z.Z. gearbeitet. Der zweite Teil der Arbeit beschreibt eine der ersten
Facile synthesis of α-Fe{sub 2}O{sub 3} nanoparticles for high-performance CO gas sensor

Energy Technology Data Exchange (ETDEWEB)

Cuong, Nguyen Duc, E-mail: nguyenduccuong@hueuni.edu.vn [College of Sciences, Hue University, 77 Nguyen Hue, Phu Nhuan Ward, Hue City (Viet Nam); Faculty of Hospitality and Tourism, Hue University, 22 Lam Hoang, Vy Da Ward, Hue City (Viet Nam); Khieu, Dinh Quang; Hoa, Tran Thai [College of Sciences, Hue University, 77 Nguyen Hue, Phu Nhuan Ward, Hue City (Viet Nam); Quang, Duong Tuan [College of Education, Hue University, 34 Le Loi, Hue City (Viet Nam); Viet, Pham Hung [Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, 334 Nguyen Trai, Hanoi (Viet Nam); Lam, Tran Dai [Graduate University of Science and Technology, Vietnamese Academy of Science and Technology, Hanoi (Viet Nam); Hoa, Nguyen Duc [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (HUST), No. 1, Dai Co Viet, Hanoi (Viet Nam); Hieu, Nguyen Van, E-mail: hieu@itims.edu.vn [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (HUST), No. 1, Dai Co Viet, Hanoi (Viet Nam)

2015-08-15

Highlights: • We have demonstrated a facile method to prepare Fe{sub 2}O{sub 3} nanoparticles. • The gas sensing properties of α-Fe{sub 2}O{sub 3} have been invested. • The results show potential application of α-Fe{sub 2}O{sub 3} NPs for CO sensors in environmental monitoring. - Abstract: Iron oxide nanoparticles (NPs) were prepared via a simple hydrothermal method for high performance CO gas sensor. The synthesized α-Fe{sub 2}O{sub 3} NPs were characterized by X-ray diffraction, nitrogen adsorption/desorption isotherm, scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and selected area electron diffraction (SAED). The SEM, TEM results revealed that obtained α-Fe{sub 2}O{sub 3} particles had a peanut-like geometry with hemispherical ends. The response of the α-Fe{sub 2}O{sub 3} NPs based sensor to carbon monoxide (CO) and various concentrations of other gases were measured at different temperatures. It found that the sensor based on the peanut-like α-Fe{sub 2}O{sub 3} NPs exhibited high response, fast response–recovery, and good selectivity to CO at 300 °C. The experimental results clearly demonstrated the potential application of α-Fe{sub 2}O{sub 3} NPs as a good sensing material in the fabrication of CO sensor.
New quaternary oxides with both families of second-order Jahn–Teller (SOJT) distortive cations: Solid-state synthesis, structure determination, and characterization of YNbTe{sub 2}O{sub 8} and YNbSe{sub 2}O{sub 8}

Energy Technology Data Exchange (ETDEWEB)

Kim, Yeong Hun [Department of Chemistry, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul 156-756 (Korea, Republic of); Jeon, Beom-Yong; You, Tae-Soo [Department of Chemistry, Chungbuk National University, Cheongju, Chungbuk 361-763 (Korea, Republic of); Ok, Kang Min, E-mail: kmok@cau.ac.kr [Department of Chemistry, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul 156-756 (Korea, Republic of)

2015-07-15

Graphical abstract: Ball-and-stick representation of YNbTe{sub 2}O{sub 8} composed of polyhedra of SOJT distortive cations, i.e., NbO{sub 6} and TeO{sub 3}, in the ac-plane. - Highlights: • Two novel tellurite and selenite (YNbQ{sub 2}O{sub 8}; Q = Te and Se) are synthesized. • YNbQ{sub 2}O{sub 8} possess both families of second-order Jahn–Teller distortive cations. • The distortive environments and bonding nature are supported by electronic structure calculations. - Abstract: Two novel quaternary mixed metal tellurite and selenite, YNbTe{sub 2}O{sub 8} and YNbSe{sub 2}O{sub 8}, respectively, have been synthesized through standard solid-state reactions using Y{sub 2}O{sub 3}, Nb{sub 2}O{sub 5}, TeO{sub 2} or SeO{sub 2} as reagents. Single crystal X-ray and powder neutron diffraction analyses have been utilized to determine the structures of the reported materials. YNbTe{sub 2}O{sub 8} and YNbSe{sub 2}O{sub 8} are isostructural to each other and crystallize in the monoclinic centrosymmetric space group, C2/m (No. 12). Due to the two families of constituent second-order Jahn–Teller (SOJT) distortive cations, i.e., Nb{sup 5+} and Te{sup 4+}/Se{sup 4+}, local asymmetric environments occur from the three-dimensional frameworks. Intra-octahedral distortions along the local C{sub 4} direction and asymmetric trigonal pyramidal coordination moieties generated by stereoactive lone pairs are observed from the NbO{sub 6} octahedra and TeO{sub 3} (or SeO{sub 3}) polyhedra, respectively. Thermogravimetric analysis, infrared and UV–vis diffuse reflectance spectroscopies, elemental analysis, out-of-center distortions, dipole moment calculations, and electronic structure calculations for the reported materials are presented.
Non-isothermal crystallization kinetics of Fe{sub 2}O{sub 3}–CaO–SiO{sub 2} glass containing nucleation agent P{sub 2}O{sub 5}/TiO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Li, Bin, E-mail: stra-ceo@163.com; Wang, Yongya; Luo, Wenqin; Li, Jingfen [Huzhou University, Department of Material Chemistry (China); Li, Jianyou [Huzhou Central Hospital, Orthopedic Department (China)

2017-03-15

Fe{sub 2}O{sub 3}–CaO–SiO{sub 2} glass ceramics containing nucleation agent P{sub 2}O{sub 5}/TiO{sub 2} were prepared by sol-gel method. The samples were characterized by X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The activation energy and kinetic parameters for crystallization of the samples were calculated by the Johnson-Mehi-Avrami (JMA) model and Augis-Bennett method according to the results of DSC. The results showed that the crystallization mechanism of Fe{sub 2}O{sub 3}–CaO–SiO{sub 2} glass, whose non-isothermal kinetic parameter n = 2.3, was consistent with surface crystallization of the JMA model. The kinetics model function of Fe{sub 2}O{sub 3}–CaO–SiO{sub 2} glass, f(α) = 2.3(1–α)[–ln(1–α)]{sup 0.57}, was also obtained. The addition of nucleation agent P{sub 2}O{sub 5}/TiO{sub 2} could reduce the activation energy, which made the crystal growth modes change from onedimensional to three-dimensional.
Vapor diffusion synthesis of rugby-shaped CoFe{sub 2}O{sub 4}/graphene composites as absorbing materials

Energy Technology Data Exchange (ETDEWEB)

Zhang, Shenli [School of Chemical Engineering and the Environment, Beijing Institute of Technology, Beijing 100081 (China); Jiao, Qingze [School of Chemical Engineering and the Environment, Beijing Institute of Technology, Beijing 100081 (China); School of Chemical Engineering and Materials Science, Beijing Institute of Technology, Zhuhai, Zhuhai 519085 (China); Hu, Ju; Li, Jingjing [School of Chemical Engineering and the Environment, Beijing Institute of Technology, Beijing 100081 (China); Zhao, Yun, E-mail: zhaoyun@bit.edu.cn [School of Chemical Engineering and the Environment, Beijing Institute of Technology, Beijing 100081 (China); Li, Hansheng; Wu, Qin [School of Chemical Engineering and the Environment, Beijing Institute of Technology, Beijing 100081 (China)

2015-05-05

Graphical abstract: CoFe{sub 2}O{sub 4} rugbies/graphene composites were prepared using a vapor diffusion method followed by calcination. As-synthesized rugby-like CoFe{sub 2}O{sub 4} particles were distributed on the graphene sheet. PVP played a key role for the formation of rugby-shaped morphology of CoFe{sub 2}O{sub 4} particles. A minimum reflection loss of −39.0 dB was observed at 10.9 GHz for the CoFe{sub 2}O{sub 4} rugbies/graphene composites with a thickness of 2 mm, and the effective absorption bandwidth was 4.7 GHz. The CoFe{sub 2}O{sub 4} rugbies/graphene composites exhibited better microwave absorbing performance than that of the CoFe{sub 2}O{sub 4} nanoparticles/graphene composites prepared without PVP. - Highlights: • CoFe{sub 2}O{sub 4} rugbies/graphene hybrids were synthesized using a vapor diffusion method. • PVP played a key role for the formation of CoFe{sub 2}O{sub 4} rugbies. • CoFe{sub 2}O{sub 4} rugbies/graphene composites showed excellent microwave absorbing property. - Abstract: Rugby-shaped CoFe{sub 2}O{sub 4}/graphene composites were synthesized using a vapor diffusion method in combination with calcination. The morphologies and structures of the products were characterized by field emission scanning electron microscopy, X-ray diffractometer, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The magnetic and electromagnetic parameters were measured using a vibrating sample magnetometer and a vector network analyzer, respectively. Results show that rugby-shaped CoFe{sub 2}O{sub 4} particles are distributed on graphene sheets. A minimum reflection loss (RL) of −39.0 dB is observed at 10.9 GHz for the sample with a thickness of 2.0 mm, and the effective absorption frequency (RL < −10 dB) ranges from 9.6 to 14.3 GHz, indicating the excellent microwave absorption performance of the products. The absorbing performance of the CoFe{sub 2}O{sub 4} rugbies/graphene composites is better than that of the Co
LIBP-Pred: web server for lipid binding proteins using structural network parameters; PDB mining of human cancer biomarkers and drug targets in parasites and bacteria.

Science.gov (United States)

González-Díaz, Humberto; Munteanu, Cristian R; Postelnicu, Lucian; Prado-Prado, Francisco; Gestal, Marcos; Pazos, Alejandro

2012-03-01

Lipid-Binding Proteins (LIBPs) or Fatty Acid-Binding Proteins (FABPs) play an important role in many diseases such as different types of cancer, kidney injury, atherosclerosis, diabetes, intestinal ischemia and parasitic infections. Thus, the computational methods that can predict LIBPs based on 3D structure parameters became a goal of major importance for drug-target discovery, vaccine design and biomarker selection. In addition, the Protein Data Bank (PDB) contains 3000+ protein 3D structures with unknown function. This list, as well as new experimental outcomes in proteomics research, is a very interesting source to discover relevant proteins, including LIBPs. However, to the best of our knowledge, there are no general models to predict new LIBPs based on 3D structures. We developed new Quantitative Structure-Activity Relationship (QSAR) models based on 3D electrostatic parameters of 1801 different proteins, including 801 LIBPs. We calculated these electrostatic parameters with the MARCH-INSIDE software and they correspond to the entire protein or to specific protein regions named core, inner, middle, and surface. We used these parameters as inputs to develop a simple Linear Discriminant Analysis (LDA) classifier to discriminate 3D structure of LIBPs from other proteins. We implemented this predictor in the web server named LIBP-Pred, freely available at , along with other important web servers of the Bio-AIMS portal. The users can carry out an automatic retrieval of protein structures from PDB or upload their custom protein structural models from their disk created with LOMETS server. We demonstrated the PDB mining option performing a predictive study of 2000+ proteins with unknown function. Interesting results regarding the discovery of new Cancer Biomarkers in humans or drug targets in parasites have been discussed here in this sense.
Kinetics and intermediate phases in epitaxial growth of Fe{sub 3}O{sub 4} films from deposition and thermal reduction

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xiaozhe [School of Science, MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter, Xi' an Jiaotong University, Xi' an 710049, ShaanXi (China); Department of Physics and Astronomy, Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, Nebraska 68588 (United States); Yang, Sen; Yang, Zhimao, E-mail: zmyang@xjtu.edu.cn, E-mail: xiaoshan.xu@unl.edu [School of Science, MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter, Xi' an Jiaotong University, Xi' an 710049, ShaanXi (China); Xu, Xiaoshan, E-mail: zmyang@xjtu.edu.cn, E-mail: xiaoshan.xu@unl.edu [Department of Physics and Astronomy, Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, Nebraska 68588 (United States)

2016-08-28

We have studied the kinetics of the transitions between the Fe{sub 2}O{sub 3} and Fe{sub 3}O{sub 4} phases as thin epilayers (∼2.5 nm) on Al{sub 2}O{sub 3} (001) substrates using time-resolved reflection high energy electron diffraction. The different iron oxide phases were identified using a combination of in-situ and ex-situ characterizations. The transition from an α-Fe{sub 2}O{sub 3} (001) epilayer to a Fe{sub 3}O{sub 4} (111) epilayer through thermal reduction was found to be determined by the Fe-O bonding energy, resulting in a long time scale. The oxidation at high temperature converts a Fe{sub 3}O{sub 4} (111) epilayer to an α-Fe{sub 2}O{sub 3} (001) epilayer quickly; at low temperature, a γ-Fe{sub 2}O{sub 3} (111) epilayer was slowly generated instead. By repeating the deposition/thermal reduction processes, a thicker Fe{sub 3}O{sub 4} (111) film was obtained, which exhibit high crystallinity and moderate magnetic coercivity.
Structural, magnetic and optical properties of Y bFe{sub 2}O{sub 4} films deposited by spin coating

Energy Technology Data Exchange (ETDEWEB)

Fujii, Tatsuo, E-mail: tfujii@cc.okayama-u.ac.jp; Okamura, Naoya; Hashimoto, Hideki; Nakanishi, Makoto [Department of Applied Chemistry, Okayama University, 3-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530 (Japan); Kano, Jun [Department of Applied Chemistry, Okayama University, 3-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530 (Japan); Japan Science and Technology Agency, PRESTO, Kawaguchi, Saitama 332-0012 (Japan); Ikeda, Naoshi [Department of Physics, Okayama University, 3-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530 (Japan)

2016-08-15

Rare-earth iron oxides (RFe{sub 2}O{sub 4}) have attracting attention as new electronic device materials because of their numerous functionalities, such as electronic ferroelectricity, ferrimagnetism, and high infrared absorption. In this paper, nearly monophasic Y bFe{sub 2}O{sub 4} films were prepared on α-Al{sub 2}O{sub 3}(001) substrates by the spin coating method using an aqueous-based Y bFe{sub 2}O{sub 4} solution. The solution was composed of a stoichiometric ratio of Y b(CH{sub 3}COO){sub 3} and Fe(NO{sub 3}){sub 3} with excess chelating agents. After heat treatment above 800 °C, well-crystallized and highly (001)-oriented Y bFe{sub 2}O{sub 4} started to epitaxially form on the substrate under controlled oxygen partial pressure with H{sub 2}/CO{sub 2} gas mixtures. X-ray pole figure analysis confirmed the following epitaxial relationship: Y bFe{sub 2}O{sub 4}[100](001)//α-Al{sub 2}O{sub 3}[100](001). Moreover formation of an Fe{sub 3}O{sub 4} interracial layer between Y bFe{sub 2}O{sub 4} and α-Al{sub 2}O{sub 3} was detected by high-resolution transmission electron microscopy. Presence of the Fe{sub 3}O{sub 4} interracial layer seemed to release the lattice misfit with the substrate. The Fe{sup 2+}/Fe{sup 3+} ratio in the obtained Y bFe{sub 2}O{sub 4} films was nearly stoichiometric and the indirect bandgap assigned to Fe{sup 2+} → Fe{sup 3+} charge transfer excitation was found to be ∼0.4 eV by optical spectroscopy. A clear magnetic transition from the paramagnetic state to the ferrimagnetic state occurred at ∼230 K.
Effect of molar ratios of MgO/Al{sub 2}O{sub 3} on the sintering behavior and thermal shock resistance of MgOAl{sub 2}O{sub 3}SiO{sub 2} composite ceramics

Energy Technology Data Exchange (ETDEWEB)

Feng, Dong, E-mail: 1078155409@qq.com [School of High Temperature Materials and Magnesium Resource Engineering, University of Science and Technology Liaoning, Anshan 114051 (China); Luo, Xudong, E-mail: luoxudongs@aliyun.com [School of High Temperature Materials and Magnesium Resource Engineering, University of Science and Technology Liaoning, Anshan 114051 (China); Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Zhang, Guodong [School of High Temperature Materials and Magnesium Resource Engineering, University of Science and Technology Liaoning, Anshan 114051 (China); Xie, Zhipeng [Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

2017-01-01

In order to determine the relationship between the property of MgOAl{sub 2}O{sub 3}SiO{sub 2} composite ceramics and molar ratios of MgO/Al{sub 2}O{sub 3}, especially the sintering behavior and thermal shock resistance, the MgOAl{sub 2}O{sub 3}SiO{sub 2} composite ceramics were fabricated with micro-size MgO, Al{sub 2}O{sub 3} powder and nano-size SiO{sub 2} as main raw materials. The sample was characterized by phase analysis, densification and thermal shock times. Moreover, field emission scanning electron microscope was also conducted to study microstructure of the samples before and after thermal shock. Effect of different molar ratios of MgO/Al{sub 2}O{sub 3} on the sintering behavior and thermal shock resistance of composite ceramics were investigated. The results showed that the sample possess better sintering behavior and thermal shock resistance with the molar ratio of MgO/Al{sub 2}O{sub 3} equal to 2/1. Grains of periclase and spinel were directly bonded together, resulting in a dense and compact microstructure, and the bulk density of obtained sample reached 3.4 g/cm{sup 3}. The microstructure of sample after thermal shock revealed that the crack propagation path was deflected and bifurcated, the main-crack propagation was restricted and more fracture energy was consumed, the thermal shock resistance of composite ceramics was greatly improved. - Highlights: • Effect of MgO/Al{sub 2}O{sub 3} on the composite ceramic was firstly researched with 1 mol% SiO{sub 2}. • Microcracks for a short distance by interlinking can eliminate the crack propagation. • The composite ceramic have optimal synthetic property with MgO/Al{sub 2}O{sub 3} was 2/1.
Hydrothermal synthesis of HoMn{sub 2}O{sub 5} nanorods and their size-dependent magnetic properties

Energy Technology Data Exchange (ETDEWEB)

Lv, Yichao; Wu, Songping, E-mail: chwsp@scut.edu.cn; Xu, Rui

2017-03-01

The HoMn{sub 2}O{sub 5} nanorods were synthesized by a surfactant-assisted hydrothermal process. The length of nanorods is readily controllable with basically constant diameter. HoMn{sub 2}O{sub 5} nanorods show recognizable divagation at T{sub N}(Ho) of 13 K between FC and ZFC curve due to the contribution of the magnetic ordering of holmium. Size-dependent magnetic properties (i.e. a critical length for magnetization) of HoMn{sub 2}O{sub 5} nanorods can be ascribed to the competition between surface strain and uncompensated spin at the surface. - Highlights: • HoMn{sub 2}O{sub 5} nanorods were synthesized by a surfactant-assisted hydrothermal route. • HoMn{sub 2}O{sub 5} nanorods show recognizable divagation at T{sub N}(Ho) of 13 K between FC and ZFC. • Size-dependent magnetic properties of HoMn{sub 2}O{sub 5} nanorods can be observed.
Blue shift in optical absorption, magnetism and light-induced superparamagnetism in γ-Fe{sub 2}O{sub 3} nanoparticles formed in dendrimer

Energy Technology Data Exchange (ETDEWEB)

Domracheva, Natalia E., E-mail: ndomracheva@gmail.com; Vorobeva, Valerya E. [Zavoisky Kazan Physical-Technical Institute (Russian Federation); Gruzdev, Matvey S. [Institute of Solution Chemistry (Russian Federation); Pyataev, Andrew V. [Kazan Federal University (Russian Federation)

2015-02-15

We are presenting the investigation of the optical, magnetic, and photoinduced superparamagnetic properties of single-domain γ-Fe{sub 2}O{sub 3} nanoparticles (NPs) with diameters of about 2.5 nm formed in second-generation poly(propylene imine) dendrimer. The optical absorption studies indicated direct allowed transition with the band gap (4.5 eV), which is blue shift with respect to the value of the bulk material. Low-temperature blocking of the NPs magnetic moments at 18 K is determined by SQUID measurements. The influence of pulsed laser irradiation on the superparamagnetic properties of γ-Fe{sub 2}O{sub 3} NPs was studied by EPR spectroscopy. It has been shown that irradiation of the sample held in vacuo and cooled in zero magnetic field to 6.9 K leads to the appearance of a new EPR signal, which decays immediately after the irradiation is stopped. The appearance and disappearance of this new signal can be repeated many times at 6.9 K when we turn on/turn off the laser. We suppose that the generation of conduction band electrons by irradiation into the band gap of the γ-Fe{sub 2}O{sub 3} changes the superparamagnetic properties of NPs. Graphical Abstract: Features of the behavior of single-domain γ-Fe{sub 2}O{sub 3} nanoparticles formed in dendrimer were found by UV-Vis and EPR spectroscopy: “blue” shift in optical absorption, a significant increase in the band gap width and variation of superparamagnetic properties under light irradiation.
Hypoeutectic melting in the UO{sub 2-x}-Gd{sub 2}O{sub 3} system

Energy Technology Data Exchange (ETDEWEB)

Journeau, Christophe, E-mail: christophe.journeau@cea.fr [CEA, DEN, SMTA, LPMA, Cadarache, F13108 St Paul lez Durance (France); Fouquart, Pascal [CEA, DEN, SMTA, LPMA, Cadarache, F13108 St Paul lez Durance (France); Domenger, Renaud; Allegri, Patrick [CEA, DEN, SGCS, LMAC, Marcoule, F30207 Bagnols sur Cèze (France)

2017-05-15

Gadolinium is one of the best neutron absorber materials and its use can be considered as a sacrificial material in a Sodium Fast Reactor core catcher in view of preventing recriticallity. A series of experiments have been conducted in the VITI induction-heated facility to study the melting in the UO{sub 2-x}-Gd{sub 2}O{sub 3} system with 60–87 mol% gadolinia. These experiments have indicated that the eutectic composition is around 92 mol% Gd{sub 2}O{sub 3} – 8 mol% UO{sub 2-x} and that the liquidus line is close to that of Popov et al. [Atom. Energ. 110 (2011) pp. 221–229] phase diagram. - Highlights: •Melting/Solidification experiments with UO{sub 2-x} and Gd{sub 2}O{sub 3} in reducing environment. •Eutectic composition around 92 mol% Gd{sub 2}O{sub 3}-8 mol% UO{sub 2-x}. •UO{sub 2-x} - Gd{sub 2}O{sub 3} liquidus line seems close to that of the pseudobinary phase diagram proposed by Popov et al. •Results will support the assessment of Gd{sub 2}O{sub 3} as a sacrificial material to mitigate criticality risk in SFR core catchers.
Improvement of the specific capacitance of V{sub 2}O{sub 5} nanobelts as supercapacitor electrode by tungsten doping

Energy Technology Data Exchange (ETDEWEB)

Zheng, Jiqi [School of Chemistry, Dalian University of Technology, Dalian 116024 (China); Zhang, Yifu, E-mail: yfzhang@dlut.edu.cn [School of Chemistry, Dalian University of Technology, Dalian 116024 (China); Jing, Xuyang [College of Chemistry and Chemical Engineering, Liaoning Normal University, Dalian 116029 (China); Wang, Qiushi; Hu, Tao [School of Chemistry, Dalian University of Technology, Dalian 116024 (China); Xing, Na [College of Chemistry and Chemical Engineering, Liaoning Normal University, Dalian 116029 (China); Meng, Changgong [School of Chemistry, Dalian University of Technology, Dalian 116024 (China)

2017-01-15

Tungsten doped vanadium pentoxide (W-doped V{sub 2}O{sub 5}) nanobelts were successfully synthesized by a facile hydrothermal route and combination of calcination. The results revealed that W atoms were successfully doped into the crystal lattice of V{sub 2}O{sub 5} matrix, indicating that the homogeneous solid-solutions of W-doped V{sub 2}O{sub 5} nanobelts were obtained. The electrochemical properties of W-doped V{sub 2}O{sub 5} nanobelts as supercapacitor electrode were investigated by cyclic voltammetry (CV) and galvanostatic charge discharge (GCD) methods. W-doped V{sub 2}O{sub 5} nanobelts exhibit the excellent capacity and good rate capability. Their specific capacitance are 407, 381, 350, 328, 295 and 273 F g{sup −1} at the current density of 0.5, 1, 2, 5, 10 and 20 A g{sup −1}, respectively. W-doped V{sub 2}O{sub 5} nanobelts also show excellent energy densities of 246, 217, 212, 199, 178 and 165 W h kg{sup −1} at a power densities of 0.99, 1.98, 3.96, 9.90, 19.80 and 39.60 kW kg{sup −1}. The specific capacitance of W-doped V{sub 2}O{sub 5} nanobelts is much higher than the previous values of V{sub 2}O{sub 5} materials, achieving the aim of improving the specific capacitance of V{sub 2}O{sub 5} nanobelts. - Graphical abstract: The specific capacitance of V{sub 2}O{sub 5} nanobelts can be greatly improved by W doping. - Highlights: • Homogeneous solid-solutions of W-doped V{sub 2}O{sub 5} were prepared. • W-doped V{sub 2}O{sub 5} nanobelts exhibit excellent electrochemical property. • High specific capacitance of 407 F g{sup −1} at 0.5 A g{sup −1} was achieved. • Specific capacitance of V{sub 2}O{sub 5} nanobelts was improved by doping method.
Superconductivity induced by oxygen doping in Y{sub 2}O{sub 2}Bi

Energy Technology Data Exchange (ETDEWEB)

Cheng, Xiyue; Deng, Shuiquan [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter (FJIRSM), Chinese Academy of Sciences (CAS), Fuzhou (China); Gordon, Elijah E. [Department of Chemistry, North Carolina State University, Raleigh, NC (United States); Whangbo, Myung-Hwan [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter (FJIRSM), Chinese Academy of Sciences (CAS), Fuzhou (China); Department of Chemistry, North Carolina State University, Raleigh, NC (United States)

2017-08-14

When doped with oxygen, the layered Y{sub 2}O{sub 2}Bi phase becomes a superconductor. This finding raises questions about the sites for doped oxygen, the mechanism of superconductivity, and practical guidelines for discovering new superconductors. We probed these questions in terms of first-principles calculations for undoped and O-doped Y{sub 2}O{sub 2}Bi. The preferred sites for doped O atoms are the centers of Bi{sub 4} squares in the Bi square net. Several Bi 6p x/y bands of Y{sub 2}O{sub 2}Bi are raised in energy by oxygen doping because the 2p x/y orbitals of the doped oxygen make antibonding possible with the 6p x/y orbitals of surrounding Bi atoms. Consequently, the condition necessary for the ''flat/steep'' band model for superconductivity is satisfied in O-doped Y{sub 2}O{sub 2}Bi. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)
Effects of NO{sub x}, {alpha}-Fe{sub 2}O{sub 3}, {gamma}-Fe{sub 2}O{sub 3}, and HCl on mercury transformations in a 7-kW coal combustion system

Energy Technology Data Exchange (ETDEWEB)

Galbreath, Kevin C.; Zygarlicke, Christopher J.; Tibbetts, James E.; Schulz, Richard L.; Dunham, Grant E. [University of North Dakota Energy and Environmental Research Center, 15 North 23rd Street, P.O. Box 9018, Grand Forks, ND 58202-9018 (United States)

2005-01-25

Bench-scale investigations indicate that NO, NO{sub 2}, hematite ({alpha}-Fe{sub 2}O{sub 3}), maghemite ({gamma}-Fe{sub 2}O{sub 3}), and HCl promote the conversion of gaseous elemental mercury (Hg{sup 0}) to gaseous oxidized mercury (Hg{sup 2+}) and/or particle-associated mercury (Hg[p]) in simulated coal combustion flue gases. In this investigation, the effects of NO{sub x}, {alpha}-Fe{sub 2}O{sub 3}, {gamma}-Fe{sub 2}O{sub 3}, and HCl on Hg transformations were evaluated by injecting them into actual coal combustion flue gases produced from burning subbituminous Absaloka and lignitic Falkirk coals in a 7-kW down-fired cylindrical furnace. A bituminous Blacksville coal known to produce an Hg{sup 2+}-rich combustion flue gas was also burned in the system. The American Society for Testing and Materials Method D6784-02 (Ontario Hydro method) or an online Hg analyzer equipped to measure Hg{sup 0} and total gaseous mercury (Hg[tot]) was used to monitor Hg speciation at the baghouse inlet (160-195 {sup o}C) and outlet (110-140 {sup o}C) locations of the system. As expected, the baseline Blacksville flue gas was composed predominantly of Hg{sup 2+} (Hg{sup 2+}/Hg[tot]=0.77), whereas Absaloka and Falkirk flue gases contained primarily Hg{sup 0} (Hg{sup 0}/Hg[tot]=0.84 and 0.78, respectively). Injections of NO{sub 2} (80-190 ppmv) at 440-880 {sup o}C and {alpha}-Fe{sub 2}O{sub 3} (15 and 6 wt.%) at 450 {sup o}C into Absaloka and Falkirk coal combustion flue gases did not significantly affect Hg speciation. The lack of Hg{sup 0} to Hg{sup 2+} conversion suggests that components of Absaloka and Falkirk combustion flue gases and/or fly ashes inhibit heterogeneous Hg{sup 0}-NO{sub x}-{alpha}-Fe{sub 2}O{sub 3} reactions or that the flue gas quench rate in the 7-kW system is much different in relation to bench-scale flue gas simulators.An abundance of Hg{sup 2+}, HCl, and {gamma}-Fe{sub 2}O{sub 3} in Blacksville flue gas and the inertness of injected {alpha}-Fe{sub 2}O{sub 3
Study of irradiation damages in MgAl{sub 2}O{sub 4} and ZnAl{sub 2}O{sub 4} spinels in the framework of nuclear waste transmutation; Dommages d'irradiation dans des ceramiques de structure spinelle MgAl{sub 2}O{sub 4} et ZnAl{sub 2}O{sub 4} application a la transmutation des dechets nucleaires

Energy Technology Data Exchange (ETDEWEB)

Thiriet-Dodane, C

2002-07-01

The transmutation of minor actinides in-reactor is one solution currently being studied for the long time management of nuclear waste. In the heterogeneous concept the radionuclides are incorporating in an inert ceramic matrix. The support material must be insensitive to radiation damage. Fission product damage is the main radiation damage source during the transmutation process and therefore it is of the utmost importance to study their effects. We irradiated spinels MgAl{sub 2}O{sub 4} (matrix of reference) and ZnAl{sub 2}O{sub 4} by fast ions (by example: {sup 86}Kr of approximately 400 MeV) simulating the fission products. Under these conditions, the damage is primarily due to the electronic energy losses (S{sub e}). One of the structural features of spinel AB{sub 2}O{sub 4} is that the two cations (A{sup 2+} and B{sup 3+}) can exchange their site. This phenomenon is quantified by the inversion parameter. We highlight by XRD in grazing incidence that the structural changes observed in MgAl{sub 2}O{sub 4} correspond to an order-disorder transition from the cation sub-networks and not to a phase shift as described in the literature. Using other techniques characterizing the space group (Raman spectroscopy) as well as the local order (NMR 27Al, spectroscopy of absorption X with the thresholds K of Al and Zn), we confirm this interpretation. Moreover, for a fluence of 10{sup 14} ions/cm{sup 2}, the loss of the order at long distance is observed thus meaning a beginning of amorphization of material. The ZnAl{sub 2}O{sub 4} spinel presents the same behaviour. For this last spinel, an evolution of the inversion parameter according to the stopping power 2 was highlighted after irradiation by ions {sup 86}Kr from approximately 20 MeV. We illustrate our study by the analysis of the results obtained in XRD of an irradiation out of composite fuel (MgAl{sub 2}O{sub 4} + UO{sub 2}) called THERMHET. (authors)
Crown ether complexes of actinide elements. An X-ray study of the conformational change of the crown ether within the UO/sub 2/(NO/sub 3/)/sub 2/(H/sub 2/O)/sub 2/(18-crown-6) molecule

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Bombieri, G; De Paoli, G [Consiglio Nazionale delle Ricerche, Padua (Italy). Lab. di Chimica e Tecnologia dei Radioelementi; Immirzi, A

1978-01-01

Uranyl nitrate dihydrate-18-crown-6 crystallizes in the triclinic system with a = 9.072(3), b = 9.144(3), c = 8.323(3) A; ..cap alpha.. = 64.53(10)/sup 0/, ..beta.. = 104.23(10)/sup 0/, ..gamma.. = 110.72(10)/sup 0/, space group P1. Its structure has been determined from three dimensional X-ray data collected with an automatic diffractometer at room temperature and refined with full matrix methods to the final conventional R value = 0.038. The uranyl group does not enter into the 18-crown-6 cavity, but presents the usual hexacoordination in the equatorial plane where two water molecules and the bidentate nitrato groups are coordinated trans to each other. The whole structure is constituted by neutral UO/sub 2/(NO/sub 3/)/sub 2/(H/sub 2/O)/sub 2/ units alternated with 18-crown-6 molecules and linked together in infinite chains developing along (001) through a hydrogen bonding system. The cyclic ether assumes two statistically non-equivalent sites in the crystal (occupancy factor 0.7 and 0.3 respectively) related to each other by a 180/sup 0/ rotation about 0(7)...0(7') axis.
Surface modification of ZnAl{sub 1.9}Eu{sub 0.05}O{sub 4} aiming to obtaining ZnAl{sub 1.9}Eu{sub 0.05}O{sub 4}/SiO{sub 2} hybrid for use as a biosensor; Modificacao da superficie do ZnAl{sub 1.9}Eu{sub 0.05}O{sub 4} visando a obtencao do hibrido ZnAl{sub 1.9}Eu{sub 0.05}O{sub 4}/SiO{sub 2} para aplicacao como biossensor

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Araujo, P.M.A.G.; Santos, P.T.A.; Costa, A.C.F.M., E-mail: pascally.guerra@gmail.com, E-mail: polyanaquimica@yahoo.com.br, E-mail: ana.costa@ufcg.edu.br [Universidade Federal de Campina Grande (UFCG), PB (Brazil); Junior, S.A.; Viana, R. S., E-mail: salvesjr@ufpe.br, E-mail: rodrigosilva.viana@yahoo.com.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil)

2017-01-15

This study aimed to investigate the influence of surface modification of ZnAl{sub 1.9}Eu{sub 0.05}O{sub 4} nanoparticles for obtaining hybrid ZnAl{sub 1.9}Eu{sub 0.05}O{sub 4}/SiO{sub 2} for application as a biosensor. Initially ZnAl{sub 1.9}Eu{sub 0.05}O{sub 4} nanoparticles were synthesized by combustion reaction and, subsequently, their surfaces were modified with silane agent. The samples were characterized by X-ray diffraction, scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and excitation and emission spectroscopy. The results showed formation of ZnAl{sub 2}O{sub 4} as the major phase. By SEM, hard agglomerates, irregularly shaped in the form of plaques, with the presence of few irregular and variables pores were observed. The surface modification was confirmed by FTIR through the silanol and siloxane groups. The excitation and emission spectra revealed the presence of a broadband of ZnAl{sub 2} O{sub 4} matrix, and fine and intense transitions from europium ion arising from doping of non-stoichiometric ZnAl{sub 2}O{sub 4} with the europium. From the results of emission and excitation, it was observed that the luminescence of ZnAl{sub 1.9}Eu{sub 0.05}O{sub 4}/SiO{sub 2} hybrid presented a small decrease in relation to the ZnAl{sub 1.9}Eu0.0{sub 5}O{sub 4} nanoparticles. This decrease was almost insignificant in relation to the benefits of silanization caused by the introduction of functional groups that promote combination of hybrid ZnAl{sub 1.9}Eu{sub 0.05}O{sub 4}/SiO{sub 2} with biomolecules, being this promising for application as a biosensor used in the biomedical field for the diagnosis and treatment of diseases. (author)
Study of conduction mechanism in Fe{sub 2}O{sub 3} doped Na{sub 2}O·Bi{sub 2}O{sub 3}·B{sub 2}O{sub 3} semiconducting glasses

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Ahlawat, Navneet [Matu Ram Institute of Engineering and Management, Rohtak 124001, Haryana (India); Aghamkar, Praveen [Department of Physics, Chaudhary Devi Lal University, Sirsa 125055, Haryana (India); Agarwal, Ashish [Department of Applied Physics, Guru Jambheshwar University of Science & Technology, Hisar 125001, Haryana (India); Ahlawat, Neetu, E-mail: neetugju@yahoo.co.in [Department of Applied Physics, Guru Jambheshwar University of Science & Technology, Hisar 125001, Haryana (India)

2016-02-01

Conduction mechanism in Fe{sub 2}O{sub 3} doped Na{sub 2}O·Bi{sub 2}O{sub 3}·B{sub 2}O{sub 3} semiconducting glass system was studied in frequency range 10 Hz to 1 MHz and at temperatures between room temperature and 663 K. The total conductivity spectrum follows universal power law with frequency exponent ‘s’ value less than unity and lies in the range 0.51≤s≤0.78. These ranges of ‘s’ values indicate that the carrier transport is predominately due to hopping electrons between charged defects and show temperature dependence as predicted by correlated barrier hopping (CBH) model. The change in activation energy of dc conductivity with temperature reveals the change in conduction mode from small polaron hopping (SPH) at high temperatures (T>θ{sub D}/2) to variable range hopping (VRH) at low temperatures (T<θ{sub D}/2). The range of density of states at Fermi level N (E{sub F})=7.25×10{sup 21}–1.32×10{sup 21} eV{sup −1} cm{sup −3} at temperatures below θ{sub D}/2 corresponds to localized states near Fermi level. The large values of activation energy W{sub 2} (0.067–0.155 eV) dominated the conduction may results in high range of temperature (T=503– 423 K) for variable-range hopping conduction in these glasses.
The xGa{sub 2}O{sub 3}–(100 − x)NaPO{sub 3} glass system: Preparation, properties and structural analysis by solid state NMR

Energy Technology Data Exchange (ETDEWEB)

Caron, A. [UCCS UMR-CNRS 8181, Université de Lille1, Villeneuve d' Ascq (France); Doumert, B. [IMMCL, Université de Lille1, Villeneuve d' Ascq (France); Tricot, G., E-mail: gregory.tricot@univ-lille1.fr [UCCS UMR-CNRS 8181, Université de Lille1, Villeneuve d' Ascq (France); LASIR UMR-CNRS 8516, Université de Lille1, Villeneuve d' Ascq (France)

2014-10-15

Insertion of Ga{sub 2}O{sub 3} in sodium metaphosphate glasses has been investigated in this paper. Materials containing up to 30 mol% of Ga{sub 2}O{sub 3} have been prepared using the standard melt-quenching technique within the xGa{sub 2}O{sub 3}–(100 − x)NaPO{sub 3} composition line. Macroscopic properties (glass transition temperature, density and molar volume) are significantly affected by the Ga{sub 2}O{sub 3} insertion. 1D {sup 71}Ga and {sup 31}P magic angle spinning nuclear magnetic resonance (MAS-NMR) performed at very high field (18.8 T) indicate a strong evolution of the gallium coordination state around the x = 15 composition and a continuous evolution of the phosphate network organisation. In addition, {sup 71}Ga({sup 31}P) D-HMQC NMR technique was used for the first time to highlight the presence of mixed P–O–Ga linkages within the glass structure. The impact of gallium insertion is finally discussed and compared to the effect of the widely used aluminum and boron elements. If gallium and aluminum elements present similar effect on the macroscopic properties, some discrepancies can be observed concerning their structural effect. - Highlights: • Glasses with 30 mol% of Ga{sub 2}O{sub 3} have been prepared in the NaPO{sub 3}–Ga{sub 2}O{sub 3} line. • T{sub g} and density are affected by the Ga{sup 3+} insertion. • Presence of mixed Ga/P species have been highlighted by 2D correlation NMR.

Thermally induced structural modifications and O{sub 2} trapping in highly porous silica nanoparticles

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Alessi, A., E-mail: antonino.alessi@unipa.it; Agnello, S.; Iovino, G.; Buscarino, G.; Melodia, E.G.; Cannas, M.; Gelardi, F.M.

2014-12-15

In this work we investigate by Raman spectroscopy the effect of isochronal (2 h) thermal treatments in air in the temperature range 200–1000 °C of amorphous silicon dioxide porous nanoparticles with diameters ranging from 5 up to 15 nm and specific surface 590–690 m{sup 2}/g. Our results indicate that the amorphous structure changes similarly to other porous systems previously investigated, in fact superficial SiOH groups are removed, Si–O–Si linkages are created and the ring statistic is modified, furthermore these data evidence that the three membered rings do not contribute significantly to the Raman signal detected at about 495 cm{sup −1}. In addition, after annealing at 900 and 1000 °C we noted the appearance of the O{sub 2} emission at 1272 nm, absent in the not treated samples. The measure of the O{sub 2} emission has been combined with electron paramagnetic resonance measurements of the γ irradiation induced HO{sup ·}{sub 2} radicals to investigate the O{sub 2} content per mass unit of thin layers of silica. Our data reveal that the porous nanoparticles have a much lower ability to trap O{sub 2} molecules per mass units than nonporous silica supporting a model by which O{sub 2} trapping inside a surface layer of about 1 nm of silica is always limited. - Highlights: • O{sub 2} emission and HO{sup ·}{sub 2} electron paramagnetic resonance signals are investigated. • Silica surface ability to trap O{sub 2} molecules is explored by thermal treatments. • Raman study of thermally induced structural changes in porous silica nanoparticles. • Raman signal attributable to the three membered rings in silica.
Bi{sub 2}O{sub 3} cocatalyst improving photocatalytic hydrogen evolution performance of TiO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Xu, Difa; Hai, Yang; Zhang, Xiangchao; Zhang, Shiying; He, Rongan, E-mail: hslra@tom.com

2017-04-01

Highlights: • Bi-Bi{sub 2}O{sub 3}-anatase-rutile TiO{sub 2} multijunction photocatalyst was prepared. • Bi{sub 2}O{sub 3} quantum dots with size of 2–3 nm were uniformly distributed. • Improved H{sub 2} evolution was noticed in glycerol-water mixture. • Optimal amount of Bi{sub 2}O{sub 3} was found to be 0.89 mol%. - Abstract: Photocatalytic hydrogen production using water splitting is of potential importance from the viewpoint of renewable energy development. Herein, Bi{sub 2}O{sub 3}-TiO{sub 2} composite photocatalysts presented as Bi-Bi{sub 2}O{sub 3}-anatase-rutile TiO{sub 2} multijunction were first fabricated by a simple impregnation-calcination method using Bi{sub 2}O{sub 3} as H{sub 2}-production cocatalysts. The obtained multijunction samples exhibit an obvious enhancement in photocatalytic H{sub 2} evolution activity in the presence of glycerol. The effect of Bi{sub 2}O{sub 3} amount on H{sub 2}-evolution activity of TiO{sub 2} was investigated and the optimal Bi{sub 2}O{sub 3} content was found to be 0.89 mol%, achieving a H{sub 2}-production rate of 920 μmol h{sup −1}, exceeding that of pure TiO{sub 2} by more than 73 times. The enhanced mechanism of photocatalytic H{sub 2}-evolution activity is proposed. This study will provide new insight into the design and fabrication of TiO{sub 2}-based hydrogen-production photocatalysts using low-cost Bi{sub 2}O{sub 3} as cocatalyst.
Facile synthesis, dielectric properties and electrocatalytic activities of PMMA-NiFe{sub 2}O{sub 4} nanocomposite

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Maji, Pranabi; Choudhary, Ram Bilash, E-mail: rbcism@gmail.com

2017-06-01

The paper deals with the dielectric and catalytic properties of poly (methyl methacrylate)-nikel ferrite (PMMA-NiFe{sub 2}O{sub 4}) nanocomposite. The nanocomposite was prepared by using a general and facile synthesis strategy. Fourier transform infrared (FTIR) and X-ray diffraction (XRD) spectra confirmed the formation of PMMA-NiFe{sub 2}O{sub 4} nanocomposite. Field effect scanning electron microscopic (FESEM) and transmission electron microscopic (TEM) images revealed that NiFe{sub 2}O{sub 4} nanoparticles were uniformly distributed and were tightly adhered with PMMA matrix owing to surface modification with 3-methacryloyloxy propyl trimethoxy silane (KH-570). Thermal stability was enhanced by incorporation of NiFe{sub 2}O{sub 4} nanofillers. The nanocomposite showed high dielectric constant and low dielectric loss. The achieved dielectric and thermal property inferred the potential application of this material in energy storage and embedded electronics devices. Further, the as prepared nanocomposite also offered a remarkable electrochemical performance towards hydrogen peroxide (H{sub 2}O{sub 2}) sensing. - Highlights: • PMMA-NiFe{sub 2}O{sub 4} nanocomposite was synthesized via free radical polymerization. • The nanocomposite exhibited high value of dielectric constant (51) and tanδ (0.3). • Thermal stability of the PMMA matrix was improved by the incorporation of NiFe{sub 2}O{sub 4.} • The H{sub 2}O{sub 2} detection limit was estimated 44 μM when signal to noise (S/N) ration was 3. • The electrochemical sensitivity of H{sub 2}O{sub 2} was calculated 0.6727 μA mM{sup -1}.
Synthesis, crystal and electronic structures, and magnetic properties of LiLn{sub 9}Mo{sub 16}O{sub 35} (Ln=La, Ce, Pr, and Nd) compounds containing the original cluster Mo{sub 16}O{sub 36}

Energy Technology Data Exchange (ETDEWEB)

Gougeon, Patrick; Gall, Philippe [UMR CNRS 6226 - ' ' Sciences Chimiques de Rennes' ' , Universite de Rennes 1 - INSA (France); Cuny, Jerome; Gautier, Regis; Le Polles, Laurent [UMR CNRS 6226 - ' ' Sciences Chimiques de Rennes' ' , Ecole Nationale Superieure de Chimie de Rennes (France); Delevoye, Laurent; Trebosc, Julien [UMR CNRS 8181 - UCCS, ENSCL, Universite Lille Nord de France, Villeneuve d' Ascq (France)

2011-12-02

The new compounds LiLn{sub 9}Mo{sub 16}O{sub 35} (Ln=La, Ce, Pr, and Nd) were synthesized from stoichiometric mixtures of Li{sub 2}MoO{sub 4}, Ln{sub 2}O{sub 3}, Pr{sub 6}O{sub 11} or CeO{sub 2}, MoO{sub 3}, and Mo heated at 1600 C for 48 h in a molybdenum crucible sealed under a low argon pressure. The crystal structure, determined from a single crystal of the Nd member, showed that the main building block is the Mo{sub 16}O{sub 36} unit, the Mo{sub 16} core of which is totally new and results from the fusion of two bioctahedral Mo{sub 10} clusters. It can also be viewed as a fragment of an infinite twin chain of edge-sharing Mo{sub 6} octahedra. The Mo{sub 16}O{sub 36} cluster units share some oxygen atoms to form infinite chains running parallel to the b axis, which are separated by the rare-earth and lithium cations. {sup 7}Li-NMR experiments, carried out at high field on the nonmagnetic LiLa{sub 9}Mo{sub 16}O{sub 35}, provided insights into the local environment of the lithium ions. Magnetic susceptibility measurements confirmed the trivalent oxidation state of the magnetic rare-earth cations and indicated the absence of localized moments on the Mo{sub 16} clusters. The electronic structure of the LiLn{sub 9}Mo{sub 16}O{sub 35} compounds was analyzed using molecular and periodic quantum calculations. The study of the molecular orbital diagrams of isolated Mo{sub 16}O{sub 36} models allowed the understanding of this unique metallic architecture. Periodic density functional theory calculations demonstrated that few interactions occur between the Mo{sub 16} clusters, and predicted semiconducting properties for LiLn{sub 9}Mo{sub 16}O{sub 35} as a band gap of 0.57 eV was computed for the lanthanum phase. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Lambda based control O{sub 2} set point optimisation and evaluation; Lambdabaserad reglering. Boervaerdesoptimering av O{sub 2} och utvaerdering

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Svensson, Mikael; Brodin, Peter [Vattenfall Utveckling, Aelvkarleby (Sweden)

2004-10-01

During winter and spring 2003, the project 'Lambda based control' was carried out at Vattenfall Utveckling AB in Aelvkarleby, Sweden. The main purpose of the project was to explore if conventional lambda sensors could be used to control the fuel/air-ratio in small boilers. The conclusion was that this is possible. To be able to make use of the result, the question of what the numerical set value for O{sub 2} should be, has to be answered. Several parameters have impact on the oxygen level in combustion gas. The main purpose of this project is to explore if there is a cost efficient way of controlling fuel/air-ratio by using lambda sensors. The scope of the project is achieve the following, by using the experience from project P4-209: find out which parameters that correlate most strongly with lambda; develop a method to decide which and how many parameters to use, in order to optimize cost efficiency; calculate optimal set value for O{sub 2} in one of the boilers used for experiments in the project; and evaluate the method and compare important parameters of operation, such as efficiency and emissions. The method developed in the project uses initial measurements to find out the relation between O{sub 2} and emissions at different power levels. Then a set point curve is calculated where set point for O{sub 2} is expressed as a function of power level in the current boiler. The method has been implemented and evaluated at a 400 kW boiler in Aelvkarleby, Sweden. The results are improvements in efficiency (6 %) and emissions, CO decreased 40 %, NO decreased by 20 %. The conclusion is that lambda based control according to this method could be a profitable investment under the right circumstances, where stability in characteristics is the most important property. What makes the method uncertain is its inability to handle changes in characteristics of a boiler.
Exchange coupling behavior in bimagnetic CoFe{sub 2}O{sub 4}/CoFe{sub 2} nanocomposite

Energy Technology Data Exchange (ETDEWEB)

Leite, G.C.P. [Instituto de Fisica, Universidade Federal de Mato Grosso, 78060-900 Cuiaba-MT (Brazil); Chagas, E.F., E-mail: efchagas@fisica.ufmt.br [Instituto de Fisica, Universidade Federal de Mato Grosso, 78060-900 Cuiaba-MT (Brazil); Pereira, R.; Prado, R.J. [Instituto de Fisica, Universidade Federal de Mato Grosso, 78060-900 Cuiaba-MT (Brazil); Terezo, A.J. [Departamento de Quimica, Universidade Federal do Mato Grosso, 78060-900 Cuiaba-MT (Brazil); Alzamora, M.; Baggio-Saitovitch, E. [Centro Brasileiro de Pesquisas Fisicas, Rua Xavier Sigaud 150 Urca, Rio de Janeiro (Brazil)

2012-09-15

In this work we report a study of the magnetic behavior of ferrimagnetic oxide CoFe{sub 2}O{sub 4} and ferrimagnetic oxide/ferromagnetic metal CoFe{sub 2}O{sub 4}/CoFe{sub 2} nanocomposite. The latter compound is a good system to study hard ferrimagnet/soft ferromagnet exchange coupled. Two steps were followed to synthesize the bimagnetic CoFe{sub 2}O{sub 4}/CoFe{sub 2} nanocomposite: (i) first, preparation of CoFe{sub 2}O{sub 4} nanoparticles using a simple hydrothermal method, and (ii) second, reduction reaction of cobalt ferrite nanoparticles using activated charcoal in inert atmosphere and high temperature. The phase structures, particle sizes, morphology, and magnetic properties of CoFe{sub 2}O{sub 4} nanoparticles were investigated by X-Ray diffraction (XRD), Mossbauer spectroscopy (MS), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM) with applied field up to 3.0 kOe at room temperature and 50 K. The mean diameter of CoFe{sub 2}O{sub 4} particles is about 16 nm. Mossbauer spectra revealed two sites for Fe{sup 3+}. One site is related to Fe in an octahedral coordination and the other one to the Fe{sup 3+} in a tetrahedral coordination, as expected for a spinel crystal structure of CoFe{sub 2}O{sub 4}. TEM measurements of nanocomposite showed the formation of a thin shell of CoFe{sub 2} on the cobalt ferrite and indicate that the nanoparticles increase to about 100 nm. The magnetization of the nanocomposite showed a hysteresis loop that is characteristic of exchange coupled systems. A maximum energy product (BH){sub max} of 1.22 MGOe was achieved at room temperature for CoFe{sub 2}O{sub 4}/CoFe{sub 2} nanocomposites, which is about 115% higher than the value obtained for CoFe{sub 2}O{sub 4} precursor. The exchange coupling interaction and the enhancement of product (BH){sub max} in nanocomposite CoFe{sub 2}O{sub 4}/CoFe{sub 2} are discussed. - Highlights: Black-Right-Pointing-Pointer CoFe{sub 2}O{sub 4}/CoFe{sub 2} nanocomposite
Ag/α-Fe{sub 2}O{sub 3} hollow microspheres: Preparation and application for hydrogen peroxide detection

Energy Technology Data Exchange (ETDEWEB)

Kang, Xinyuan; Wu, Zhiping; Liao, Fang, E-mail: liaozhang2003@163.com; Zhang, Tingting; Guo, Tingting

2015-09-15

In this paper, we demonstrated a simple approach for preparing α-Fe{sub 2}O{sub 3} hollow spheres by mixing ferric nitrate aqueous and glucose in 180 °C. The glucose was found to act as a soft template in the process of α-Fe{sub 2}O{sub 3} hollow spheres formation. Ag/α-Fe{sub 2}O{sub 3} hollow nanocomposite was obtained under UV irradiation without additional reducing agents or initiators. Synthesized Ag/α-Fe{sub 2}O{sub 3} hollow composites exhibited remarkable catalytic performance toward H{sub 2}O{sub 2} reduction. The electrocatalytic activity mechanism of Ag/α-Fe{sub 2}O{sub 3}/GCE were discussed toward the reduction of H{sub 2}O{sub 2} in this paper. - Graphical abstract: Glucose is carbonized as carbon balls in the 180 °C hydrothermal carbonization process, which plays a role of a soft template. Carbon spherical shell is rich in many hydroxyls, which have good hydrophilicity and surface reactivity. When Fe(NO{sub 3}){sub 3} is added to the aqueous solution of Glucose, the hydrophilic -OH will adsorb Fe{sup 3+} to form coordination compound by coordination bond. α-FeOOH is formed on the surface of carbon balls by hydrothermal reaction. After calcination at 500 °C, carbon spheres react with oxygen to form carbon dioxide, which disappears in the air. Meanwhile α-FeOOH is calcined to form α-Fe{sub 2}O{sub 3} hollow spheres.
Charge ordering and exchange bias behaviors in Co{sub 3}O{sub 4} porous nanoplatelets and nanorings

Energy Technology Data Exchange (ETDEWEB)

Debnath, J.C., E-mail: jcd341@uowmail.edu.au [Institute for Frontier Materials, Deakin University, Geelong, VIC 3216 (Australia); Wang, Jianli [Institute for Superconductivity and Electronic Materials, University of Wollongong, Wollongong, NSW 2522 (Australia); Zeng, R. [Institute for Superconductivity and Electronic Materials, University of Wollongong, Wollongong, NSW 2522 (Australia); School of Materials Science and Engineering, Faculty of Science, UNSW, Sydney NSW 2052 (Australia)

2017-01-01

We present the synthesis of α-Co{sub 3}O{sub 4} porous nanoplatelets and hexagonal nanorings using microwave-assisted hydrothermal and conventional chemical reaction methods. The x-ray diffraction (XRD) and refinement analyses indicate the α-Co{sub 3}O{sub 4} crystal structure, and the x-ray photoelectron spectrum (XPS) indicates the high purity of the samples. The M–T (including 1/χ–T) curves indicate an antiferromagnetic transition at about 35 K in both kind of samples but the interesting finding was made that a charge-ordered (CO) state appears at 250 K for the nanoplatelets sample whereas it is inattentive for the nanorings. The antiferromagnetic transition temperature T{sub N} is lower than that of the bulk α-Co{sub 3}O{sub 4} single crystal due to the nanosized structures. We observed quite significant exchange bias for nanorings. The exchange bias behavior of the α-Co{sub 3}O{sub 4} hexagonal nanorings is consistent with an antiferromagnetic (AFM) Co{sub 3}O{sub 4} core and spin-glass like shell. - Highlights: ●Charge-ordered state appears for the Co{sub 3}O{sub 4} nanoplatelets but absent for the nanorings. ●Quite significant exchange bias is only observed for Co{sub 3}O{sub 4} nanorings. ●Exchange bias behavior of Co{sub 3}O{sub 4} nanorings is consistent with spin-glass like shell. ●Potential for ultrahigh-density magnetic recording and spin valve devices.
Forged HITEMAL: Al-based MMCs strengthened with nanometric thick Al{sub 2}O{sub 3} skeleton

Energy Technology Data Exchange (ETDEWEB)

Balog, Martin, E-mail: ummsbama@savba.sk [Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Racianska 75, 83102 Bratislava (Slovakia); Krizik, Peter; Nosko, Martin; Hajovska, Zuzana [Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Racianska 75, 83102 Bratislava (Slovakia); Victoria Castro Riglos, Maria [Centro Atómico Bariloche, Av. Bustillo 9.500, 8400 Bariloche, Río Negro (Argentina); Rajner, Walter [New Materials Development GmbH, Römerstrasse 28, 83410 Laufen, Leobendorf (Germany); Liu, De-Shin [National Chung Cheng University, 168 University Rd., Min-Hsiung, 62102 Chia-Yi, Taiwan (China); Simancik, Frantisek [Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Racianska 75, 83102 Bratislava (Slovakia)

2014-09-08

Bulk Al–Al{sub 2}O{sub 3} metal matrix composites (MMCs) named HITEMAL (high temperature aluminum) were fabricated in situ by forging compaction of five different types of gas-atomized commercial purity Al powders with a mean particle size in the range of 1–9 µm. As-forged HITEMAL consisted of (sub)micrometric Al grains (matrix) decorated with nanometric thick amorphous Al{sub 2}O{sub 3} (a-Al{sub 2}O{sub 3}) skeleton. Low-angle grain boundaries (LAGBs) free of Al{sub 2}O{sub 3} were located in the Al grain interior. The Al grain size and the portion of LAGBs increased with the increase in the relative powder surface area. As-forged HITEMAL shows excellent thermal stability up to 400 °C for 24 h. Annealing at temperatures ≥450 °C led to crystallization and morphological transformation from a-Al{sub 2}O{sub 3} skeleton to nanometric γ-Al{sub 2}O{sub 3} particles. Owing to the pinning effect of Al{sub 2}O{sub 3} phase, no Al grain growth took place during annealing up to 500 °C. HITEMAL showed attractive mechanical properties especially when tested at 300 °C (yield strength up to 220 MPa, Young's modulus up to 58 GPa). Despite the presence of a nearly continuous a-Al{sub 2}O{sub 3} skeleton along adjacent Al grains, forged HITEMAL materials had reasonable room temperature elongation of 7–26%. HITEMAL's elongation decreased as the Al grain size decreased and with increased testing temperature. The loss in elongation (uniform and total) was attributed to the inhomogeneous flow, which occurred due to high densities of high angle grain boundaries (dislocation sinks) and small content of LAGBs. The strength of HITEMAL stemmed from grain boundary mediated strengthening mechanisms. The results showed a positive deviation from the Hall–Petch plot, which is typical behavior of ultrafine-grained metals. Transformation of a-Al{sub 2}O{sub 3} skeleton to γ-Al{sub 2}O{sub 3} particles led to deterioration of the HITEMAL strength and Young's modulus.
Doping of low-T{sub g} phosphate glass with Al{sub 2}O{sub 3}, B{sub 2}O{sub 3} and SiO{sub 2}: Part I- effect on glass property and stability

Energy Technology Data Exchange (ETDEWEB)

Rajbhandari, P., E-mail: p.rajbhandari@sheffield.ac.uk [UCCS UMR-CNRS 8181, Universite de Lille1, Villeneuve d' Ascq (France); Montagne, L. [UCCS UMR-CNRS 8181, Universite de Lille1, Villeneuve d' Ascq (France); Tricot, G. [UCCS UMR-CNRS 8181, Universite de Lille1, Villeneuve d' Ascq (France); LASIR UMR-CNRS 8516, Universite de Lille1, Villeneuve d' Ascq (France)

2016-11-01

A zinc alkali pyrophosphate system 46.6ZnO-20Na{sub 2}O-33.5P{sub 2}O{sub 5} presenting low-T{sub g} (339 °C) and good thermal stability has been doped with (1–4) mol% of Al{sub 2}O{sub 3}, B{sub 2}O{sub 3} and SiO{sub 2} to improve the stability of the glass with a minimal increase in glass transition temperature (T{sub g}). XRD and 1D {sup 31}P solid state NMR were used to monitor the isothermal crystallization process occurring at 130 °C above T{sub g}. If the Al{sub 2}O{sub 3} and B{sub 2}O{sub 3} doping significantly improved thermal stability, this property was marginally affected by SiO{sub 2} doping. Viscosity measurements were performed to observe the crystallization effects induced by the doping. It is noteworthy that the T{sub g} values of all the doped compositions with improved stability presented in this work are below 400 °C. Raman spectroscopy, 1D {sup 31}P, {sup 27}Al, {sup 11}B and {sup 29}Si solid state NMR were carried out to determine the structural modifications and coordination states of the doping elements all along the composition line. - Highlights: • Low-Tg phosphate glasses doped with Al{sub 2}O{sub 3}, B{sub 2}O{sub 3} and SiO{sub 2} have been formulated. • Thermal stability of the glass has been improved significantly. • The structural modification induced by doping elements has been studied by employing solid state NMR technique.
Hot and cold CO{sub 2}-rich mineral waters in Chaves geothermal area (northern Portugal)

Energy Technology Data Exchange (ETDEWEB)

Aires-Barros, Luis; Marques, Jose Manuel; Graca, Rui Cores; Matias, Maria Jose [Universidade Tecnica de Lisboa, Lab. de Mineralogia e Petrologia (LAMPIST), Lisboa (Portugal); Weijden, Cornelis H. van der; Kreulen, Rob [Utrecht Univ., Dept. of Geochemistry, Utrecht (Netherlands); Eggenkamp, Hermanus Gerardus M. [Utrecht Univ., Dept. of Geochemistry, Utrecht (Netherlands); Reading Univ., Postgraduate Research Inst. for Sedimentology, Reading (United Kingdom)

1998-02-01

In order to update the geohydrologic characterisation of Chaves geothermal area, coupled isotopic and chemical studies have been carried out on hot and cold CO{sub 2}-rich mineral waters discharging, in northern Portugal, along one of the major regional NNE-trending faults (the so-called Verin-Chaves-Penacova Depression). Based upon their location, and chemical and isotopic composition, the analysed waters can be divided into two groups. The northern group belongs to the HCO{sub 3}/Na/CO{sub 2}-rich type, and consists of the hot spring waters of Chaves and the cold spring waters of Vilarelho da Raia. The {delta}D and {delta}{sup 18}O values show that these waters are of meteoric origin. The lack of an {sup 18}O shift indicates that there is no evidence of water/rock interaction at high temperatures. The southern group includes the cold spring waters of Campilho/Vidago and Sabroso/Pedras Salgadas. Their chemistry is similar to that of the northern group but their heavier {delta}D and {delta}{sup 18}O values could be attributed to different recharge altitudes. Mixing between deep mineralised waters and dilute superficial waters of meteoric origin might explain the higher {sup 3}H activity found in the Vidago and Pedras Salgadas mineral waters. Alternatively, they could be mainly related to shallow underground flowpaths. The {delta}{sup 13}C values support a deep-seated origin for the CO{sub 2}. The {delta}{sup 37}Cl is comparable in all the mineral waters of the study areas, indicating a common origin of Cl. The {sup 87}Sr/{sup 86}Sr ratios in waters seem to be dominated by the dissolution of plagioclases or granitic rocks. (Author)
Catalytic properties of oxygen adsorbed on NiO-Sm/sub 2/O/sub 3/ binary oxides

Energy Technology Data Exchange (ETDEWEB)

Tadasu, Y.; Niwa, H.; Matsuda, Y.

1978-02-01

Various rare earths were screened as promoters for a nickel oxidation catalyst, and samarium (Sm) was selected for further studies. The activity of a physical mixture of NiO/Sm/sub 2/O/sub 3/ and SiC for the oxidation of 500 ppm nitric oxide with 5% oxygen in nitrogen to nitrogen dioxide at 320/sup 0/C went through a maximum with increasing Sm/sub 2/O/sub 3/ content of the catalyst. The most active catalyst, which contained 3.75% Sm/sub 2/O/sub 3/, was 3.7 times as active as pure nickel oxide. Temperature-programed desorption of oxygen from the catalysts revealed three peaks, ..cap alpha.. at 220/sup 0/-230/sup 0/C ..beta.. at 370/sup 0/-380/sup 0/C, and ..gamma.. at 530/sup 0/-540/sup 0/C, for all catalysts except pure Sm/sub 2/O/sub 3/. The amount of adsorbed oxygen increased with increasing Sm/sub 2/O/sub 3/ content to 3.75%, and then decreased with further Sm/sub 2/O/sub 3/ increases. The catalytic activity was correlated to oxygen in the ..beta..-state. Graphs, spectra, and table.
ZnFe{sub 2}O{sub 4} antiferromagnetic structure redetermination

Energy Technology Data Exchange (ETDEWEB)

Kremenović, Aleksandar, E-mail: akremenovic@rgf.bg.ac.rs [Laboratory for Crystallography, Faculty of Mining and Geology, University of Belgrade, Đušina 7, Belgrade 11000 (Serbia); Antić, Bratislav [Condensed Matter Physics Laboratory, Institute of Nuclear Sciences “Vinča”, University of Belgrade, P.O. Box 522, Belgrade 11001 (Serbia); Vulić, Predrag [Laboratory for Crystallography, Faculty of Mining and Geology, University of Belgrade, Đušina 7, Belgrade 11000 (Serbia); Blanuša, Jovan [Condensed Matter Physics Laboratory, Institute of Nuclear Sciences “Vinča”, University of Belgrade, P.O. Box 522, Belgrade 11001 (Serbia); Tomic, Aleksandra [Condensed Matter Physics Laboratory, Institute of Nuclear Sciences “Vinča”, University of Belgrade, P.O. Box 522, Belgrade 11001 (Serbia); Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY, 10027 (United States)

2017-03-15

Magnetic structure of ZnFe{sub 2}O{sub 4} normal spinel is re-examined. Antiferromagnetic structure non-collinear model is established within C{sub a}2 space group having four different crystallographic/magnetic sites for 32 Fe{sup 3+} spins within magnetic unit cell. - Highlights: • Magnetic structure of ZnFe{sub 2}O{sub 4} normal spinel is re-examined. • Antiferromagnetic non-collinear structure model is established within C{sub a}2 space group. • Four different crystallographic/magnetic sites contain 32 Fe{sup 3+} spins within magnetic unit cell.
A [Mo{sub 2}O{sub 2}S{sub 2}]-based ring system incorporating tartrate as the bridging ligand. Synthesis, structure and catalytic activity of Cs{sub 4}[Mo{sub 2}O{sub 2}(μ-S){sub 2}]{sub 2}(μ{sub 4}-tart){sub 2} (tart=[C{sub 4}H{sub 2}O{sub 6}]{sup 4-})

Energy Technology Data Exchange (ETDEWEB)

Qian, Ting-Ting; Cui, Yu-Jie; Xin, Zhifeng; Jia, Ai-Quan; Zhang, Qian-Feng [Anhui Univ. of Technology, Anhui (China). Inst. of Molecular Engineering and Applied Chemistry and Anhui Province Key Lab. of Metallurgy Engineering and Resources Recycling

2017-08-01

Treatment of [Mo{sub 2}S{sub 2}O{sub 2}(H{sub 2}O){sub 6}]{sup 2+} with racemic tartaric acid (tartH{sub 4}) in the presence of sodium hydroxide and cesium chloride in aqueous solution led to the isolation of a new tetra-molybdenum ring cluster Cs{sub 4}[Mo{sub 2}O{sub 2}(μ-S){sub 2}]{sub 2}(μ{sub 4}-tart){sub 2}. The cyclic cluster polyanion consists of two dinuclear [Mo{sub 2}O{sub 2}(μ-S){sub 2}]{sup 2+} moieties and two bridging tart{sup 4-} ligands. The cyclic polyoxothiomolybdate cluster, supported on the mesoporous silica SBA-15, was tested for heterogenerous catalysis in thiophene hydrodesulfurization.
Multiple-stage diagenetic alteration and fluid history of Ordovician carbonate-hosted barite mineralization, Southern Quebec Appalachians

Science.gov (United States)

Paradis, Suzanne; Lavoie, Denis

1996-12-01

Lower Ordovician bioclastic limestone of the Upton Group, southern Quebec Appalachians, hosts stratabound Ba-Zn-Pb mineralization. The Upton Group, a mixed platform carbonate-siliciclastic-volcanic succession, is exposed as windows within the tectonically overlying Cambrian siliciclastics of the Granby Nappe. Mineralization consists mostly of barite and minor amounts of sulfides (sphalerite, pyrite, galena, and chalcopyrite), in addition to calcite, quartz and bitumen cements. It is hosted by a bioclastic limestone which is interbedded with and capped by a black calcareous shale, and underlain by a mudstone-siltstone-volcanic succession and a lower poorly fossiliferous limestone. The lower limestone recorded early extensive dolomitization followed by meteoric alteration (dedolomitization, sulphate dissolution, vadose cements, soil pisoids, etc.), and burial diagenesis (recrystallization, fracturation, and cementation). The vadose gravitational calcite cements yield δ 18O PDB values of -8.4 to -11.0‰ andδ 13C PDB values of +2.4 to +2.8‰. The thin soil profiles with pisoids have a δ 18O PDB value of -8.2‰ and a δ 13C PDB value of +2.0‰. These data suggest an evaporative 18O-enrichment of near-surface trapped soil moisture (vadose water) in a rock-dominated diagenetic system. The recrystallized limestone hasδ 18O PDB values of -11.4 to -15.5‰ and near Early Ordovician marine δ 13C PDB values of -0.2 to +2.5‰. These data suggest a final stabilization of the limestone from high temperature fluids in a rock-dominated diagenetic system. The mineralized bioclastic limestone shows rare evidence of early submarine cementation which is overprinted by significant post-depositional recrystallization and hydrothermal alteration. The latter resulted in the generation of secondary porosity and precipitation of a subhedral barite cement, a bladed barite cement, and fracture-filling barite. Fracture- and void-filling calcite, sulfides, quartz and bitumen
Nickel catalyst supported on magnesium and zinc aluminates (MgAl{sub 2}O{sub 4} and ZnAl{sub 2}O{sub 4}) spinels for dry reforming of methane

Energy Technology Data Exchange (ETDEWEB)

Araujo, L.C.B. de; Melo, D.M. de A.; Melo, M.A. de F.; Barros, J.M. de F.; Braga, R.M.; Costa, C. de C.; Rodrigues, G., E-mail: ieda.garcia@pq.cnpq.br [Universidade Federal da Paraiba (LACOM/UFPB), Joao Pessoa, PB (Brazil). Dept. de Quimica

2017-01-15

Materials such as MgAl{sub 2}O{sub 4} and ZnAl{sub 2}O{sub 4} assessed in the reaction of dry reforming of methane to produce syngas were synthesized by microwave-assisted combustion method using urea as fuel. Samples of synthesized oxides were calcined at 800 °C for 2 h and impregnated with 5% nickel. The impregnated samples were calcined at 850 °C for 4 h to obtain the desired phases. The results of the catalytic tests showed that the catalysts are active for the reaction of dry reforming of methane, and the catalyst that showed the best performance for methane conversion was 5% Ni/MgAl{sub 2}O{sub 4} calcined at 850 °C/4 h. (author)
Clumped-isotope geochemistry of carbonates: A new tool for the reconstruction of temperature and oxygen isotope composition of seawater

Energy Technology Data Exchange (ETDEWEB)

Bernasconi, Stefano M., E-mail: Stefano.bernasconi@erdw.ethz.ch [Geological Institute, ETH Zuerich, Sonneggstrasse 5, 8092 Zuerich (Switzerland); Schmid, Thomas W.; Grauel, Anna-Lena [Geological Institute, ETH Zuerich, Sonneggstrasse 5, 8092 Zuerich (Switzerland); Mutterlose, Joerg [Institut fuer Geologie, Mineralogie und Geophysik, Ruhr Universitaet Bochum, Universitaetsstr. 150, 44801 Bochum (Germany)

2011-06-15

Highlights: > Clumped-isotope thermometry of carbonates is discussed. > Clumped isotopes of Belemnites show higher sea surface temperatures than commonly assumed for the lower Cretaceous. > The potential of clumped-isotope measurement on foraminifera is discussed. - Abstract: Clumped-isotope geochemistry deals with State of ordering of rare isotopes in molecules, in particular with their tendency to form bonds with other rare isotopes rather than with the most abundant ones. Among its possible applications, carbonate clumped-isotope thermometry is the one that has gained most attention because of the wide potential of applications in many disciplines of the earth sciences. In particular, it allows reconstructing the temperature of formation of carbonate minerals without knowledge of the isotopic composition of the water from which they were formed. In addition, the O isotope composition of the waters from which they were formed can be calculated using the {delta}{sup 18}O of the same carbonate sample. This feature offers new approaches in paleoclimatology for reconstructing past global geochemical cycles. In this contribution two applications of this method are presented. First the potential of a new analytical method of measurement of clumped isotopes on small samples of foraminifera, for high-resolution SST and seawater {delta}{sup 18}O reconstructions from marine sediments is shown. Furthermore the potential of clumped isotope analysis of belemnites, for reconstructing seawater {delta}{sup 18}O and temperatures in the Cretaceous is shown.
Mesoporous Fe{sub 3}O{sub 4}/hydroxyapatite composite for targeted drug delivery

Energy Technology Data Exchange (ETDEWEB)

Gu, Lina; He, Xiaomei; Wu, Zhenyu, E-mail: zhenyuwuhn@sina.com

2014-11-15

Highlights: • Mesoporous Fe{sub 3}O{sub 4}/hydroxyapatite composite was synthesized by a simple, efficient and environmental friendly method. • The prepared material had a large surface area, high pore volume, and good magnetic separability. • DOX-loaded Fe{sub 3}O{sub 4}/hydroxyapatite composite exhibited surprising slow drug release behavior and pH-dependent behavior. - Abstract: In this contribution, we introduced a simple, efficient, and green method of preparing a mesoporous Fe{sub 3}O{sub 4}/hydroxyapatite (HA) composite. The as-prepared material had a large surface area, high pore volume, and good magnetic separability, which made it suitable for targeted drug delivery systems. The chemotherapeutic agent doxorubicin (DOX) was used to investigate the drug release behavior of Fe{sub 3}O{sub 4}/HA composite. The drug release profiles displayed a little burst effect and pH-dependent behavior. The release rate of DOX at pH 5.8 was larger than that at pH 7.4, which could be attributed to DOX protonation in acid medium. In addition, the released DOX concentrations remained at 0.83 and 1.39 μg/ml at pH 7.4 and 5.8, respectively, which indicated slow, steady, and safe release rates. Therefore, the as-prepared Fe{sub 3}O{sub 4}/hydroxyapatite composite could be an efficient platform for targeted anticancer drug delivery.
Hierarchical Cr{sub 2}O{sub 3}@OPC composites with octahedral shape for rechargeable nonaqueous lithium-oxygen batteries

Energy Technology Data Exchange (ETDEWEB)

Gan, Yongqing; Lai, Yanqing; Zhang, Zhian, E-mail: zhangzhian@csu.edu.cn; Chen, Wei; Du, Ke; Li, Jie

2016-04-25

The development of catalyst materials is the most significant issue that hinders the practical applications of Li-O{sub 2} batteries. Herein we show the design and synthesis of the hierarchical chromic oxide-octahedral porous carbon (Cr{sub 2}O{sub 3}@OPC) composites catalyst with octahedral shape that derived from Cr-based metal-organic frameworks (MIL-101(Cr)) precursor. When applied as cathode catalysts in rechargeable Li-O{sub 2} batteries, the electrode with Cr{sub 2}O{sub 3}@OPC composites catalyst exhibits a low charge and discharge over-potential, high discharge capacity and excellent cycling stability. What's more, the electrode with Cr{sub 2}O{sub 3}@OPC composite shows a discharge capacity up to ∼4800 mAh g{sub (catalyst} {sub +} {sub carbon)}{sup −1} at a current density of 0.1 mA cm{sup −2}, and exhibits a very stable discharge voltage plateau of 2.7 V and a charge voltage plateau of ∼3.9 V. With the addition of Cr{sub 2}O{sub 3}@OPC composite, the Li-O{sub 2} batteries can obtain good cycle performance over 50 cycles at a fixed capacity of 800 mAh g{sub (catalyst} {sub +} {sub carbon)}{sup −1}. These results indicating that the Cr{sub 2}O{sub 3}@OPC composite derived from MIL-101(Cr) would be a promising catalyst for Li-O{sub 2} batteries. - Highlights: • The Cr{sub 2}O{sub 3}@C composites were prepared by the pyrolysis of Cr-MIL-101. • The Cr{sub 2}O{sub 3}@C composites possess octahedral shape consisted of Cr{sub 2}O{sub 3}@C nanoparticle. • The Cr{sub 2}O{sub 3}@C composites have mesoporous structure with large specific area. • The Cr{sub 2}O{sub 3}@C composites have an excellent intrinsic electrocatalytic activity. • The Cr{sub 2}O{sub 3}@C electrode exhibits great cycling performance.
The peroxidase and oxidase-like activity of NiCo{sub 2}O{sub 4} mesoporous spheres: Mechanistic understanding and colorimetric biosensing

Energy Technology Data Exchange (ETDEWEB)

Su, Li, E-mail: suli@htu.edu.cn [Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Normal University, Xinxiang, Henan 453007 (China); Henan Key Laboratory of Green Chemical Media and Reactions, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007 (China); Dong, Wenpei; Wu, Chengke; Gong, Yijun; Zhang, Yan; Li, Ling; Mao, Guojiang; Feng, Suling [Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Normal University, Xinxiang, Henan 453007 (China); Henan Key Laboratory of Green Chemical Media and Reactions, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007 (China)

2017-01-25

The synthesized NiCo{sub 2}O{sub 4} mesoporous spheres (MS) displayed intrinsic peroxidase and oxidase-like activity were firstly reported. The catalytic mechanism of the oxidase-like activity of NiCo{sub 2}O{sub 4} MS was analyzed in detail using the electron spin resonance (ESR) method. It is found that NiCo{sub 2}O{sub 4} MS could directly oxidize 3,3′,5,5′-tetramethylbenzidine (TMB) but did not produce {sup 1}O{sub 2} and ·OH. And the mechanism of the peroxidase-like activity of NiCo{sub 2}O{sub 4} MS was also verified that the oxidation of TMB stemmed from not only ·OH but also {sup 1}O{sub 2}. Based on the NiCo{sub 2}O{sub 4} MS showed excellent peroxidase-like activity over a broad temperature range, especially at normal body temperature, a detection tool was designed for glucose determination in diabetics' serum samples. And this detection method based on NiCo{sub 2}O{sub 4} MS gave a lower limit of detection than the method using Co{sub 3}O{sub 4} NPs and NiO NPs, as the single-component oxides of NiCo{sub 2}O{sub 4}. Our study may open up the possibility to make a great influence on the next generation of enzyme mimetics system. - Highlights: • NiCo{sub 2}O{sub 4} MS were found to possess the peroxidase and oxidase-like activity. • The peroxidase-like activity of NiCo{sub 2}O{sub 4} MS was stemmed from not only ·OH but also {sup 1}O{sub 2}. • The oxidase-like activity may stem from NiCo{sub 2}O{sub 4} MS′ oxidation rather than ·OH and {sup 1}O{sub 2}. • A colorimetric detection tool is designed for glucose determination in serum samples.

Thermodynamic properties of Y/sub 3/Fe/sub 5/O/sub 12/ and TbFeO/sub 3/

Energy Technology Data Exchange (ETDEWEB)

Shchelkotunov, V A; Danilov, V N; Reznitskii, L A; Korobeinikova, A V [Moskovskij Gosudarstvennyj Univ. (USSR)

1975-01-01

Two types of chemical compounds-garnets and perovskites - exist in Fe/sub 2/O/sub 3/-Y/sub 2/O/sub 3/ and Fe/sub 2/O/sub 3/-Tb/sub 2/..omega../sub 3/ systems. Both of them are noncompensated antiferromagnetics. Thermal-physical properties of TbFeO/sub 3/ were determined. Values of Csub(p),(Hsub(t)-Hsub(o)) and Ssub(T) in the temperature range 298 to 700 deg K for Y/sub 3/Fe/sub 5/O/sub 12/ and in the range 298 to 600 deg K for TbFeO/sub 3/ were calculated using the experimental data on TbFeO/sub 3/ and Y/sub 3/Fe/sub 5/O/sub 12/ thermal capacity. Magnetic contribution for Y/sub 3/Fe/sub 5/O/sub 12/ Usub(mag)=1617 cal/mol and ..delta..S=3.44 cal/mol.deg. was determined.
Solubility limit and luminescence properties of Eu{sup 3+} ions in Al{sub 2}O{sub 3} powder

Energy Technology Data Exchange (ETDEWEB)

Onishi, Yuya; Nakamura, Toshihiro, E-mail: tnakamura@gunma-u.ac.jp; Adachi, Sadao, E-mail: adachi@gunma-u.ac.jp

2016-08-15

Al–Eu–O compounds are synthesized from Al{sub 2}O{sub 3}:Eu{sub 2}O{sub 3}=(1–x):x mixtures (x=0–0.15) by the metal organic decomposition method and subsequently calcined at various temperatures from T{sub c}=750 to 1200 °C in dry O{sub 2} atmosphere. The structural and luminescence properties of these compounds are investigated using X-ray diffraction analysis, photoluminescence (PL) analysis, PL excitation spectroscopy, and luminescence lifetime measurements. The present study focuses on the effects of the Eu{sub 2}O{sub 3} addition (x) on the material and phosphor properties of Al{sub 2}O{sub 3}:Eu{sup 3+}. The stable phase of α-Al{sub 2}O{sub 3} is synthesized at T{sub c}>1100 °C and cubic γ-Al{sub 2}O{sub 3} phase at T{sub c}≤1100 °C. The calcination temperature dependence of the PL intensity yields an activation of E{sub a}~0.8 eV for Eu{sup 3+} ions in the Al{sub 2}O{sub 3} host. The luminescence decay time is determined to be ~0.8 ms, independent of x. Temperature dependence of the PL intensity at T=20–450 K exhibits thermal quenching behavior with energies of 17 meV and 0.28 eV at low (<200 K) and high temperatures (>200 K), respectively. The solubility limit of Eu{sup 3+} ions in α-Al{sub 2}O{sub 3} is determined to be ~1%. The schematic energy-level diagram of Eu{sup 3+} in α-Al{sub 2}O{sub 3} is also proposed for the sake of a better understanding of the luminescence process of this phosphor system.
Magnetic properties of nanoscaled paramelaconite Cu{sub 4}O{sub 3−x} (x=0.0 and 0.5)

Energy Technology Data Exchange (ETDEWEB)

Djurek, D., E-mail: danijel.djurek@zg.t-com.hr [A. Volta Applied Ceramics (AVAC), 49247 Zlatar Bistrica, A. Šenoe 14 (Croatia); Prester, M.; Drobac, Dj. [Institute of Physics, 10000 Zagreb, Bijenička c. 46 (Croatia); Ivanda, M.; Vojta, D. [Ruđer Bošković Institute, 10000 Zagreb, Bijenička c. 54 (Croatia)

2015-01-01

Pure paramelaconite Cu{sub 4}O{sub 3−x} has been prepared in the form of nanoparticles with 56 nm in diameter. This mixed valency oxide crystallizes in a tetragonal lattice with 4 unit formulae and forms a pyrochlore structure which manifests in two stoichiometric forms; Cu{sub 4}O{sub 3} and Cu{sub 4}O{sub 2.5}, the latter form having two oxygen vacancies per unit cell. Magnetic lattice consists of Cu spin 1/2, and both stoichiometric forms obey transition to the antiferromagnetic state at T{sub N}=45–55 K. Defect free Cu{sub 4}O{sub 3} is indicated by an inversion symmetry and exhibits both antiferromagnetic and ferromagnetic state, where the latter is supposedly due to the superexchange interaction in Cu–O(1n)–Cu bonds. An additional magnetic transition was observed in Cu{sub 4}O{sub 3} at T=120 K, probably as a result of an incommensurate ordering. Absence of an inversion symmetry in the oxygen defect Cu{sub 4}O{sub 2.5} results in a long range Dzyaloshinsky–Moriya interaction accompanied by the strong superparamagnetism. - Highlights: • The first successful preparation of pure paramelaconite Cu{sub 4}O{sub 3−x}. • High resolution AC susceptibility measurements. • Evidence is presented for two stoichiometric forms of paramelaconite; defect free Cu{sub 4}O{sub 3} and Cu{sub 4}O{sub 2.5}. • Additional magnetic transition is observed at T=120 K in the defect free Cu{sub 4}O{sub 3}.
A simple large-scale synthesis of mesoporous In{sub 2}O{sub 3} for gas sensing applications

Energy Technology Data Exchange (ETDEWEB)

Zhang, Su; Song, Peng, E-mail: mse_songp@ujn.edu.cn; Yan, Huihui; Yang, Zhongxi; Wang, Qi, E-mail: mse_wangq@ujn.edu.cn

2016-08-15

Graphical abstract: Large-scale mesoporous In{sub 2}O{sub 3} nanostructures for gas-sensing applications were successfully fabricated via a facile Lewis acid catalytic the furfural alcohol resin template route. - Highlights: • Mesoporous In{sub 2}O{sub 3} nanostructures with high-yield have been successfully fabricated via a facile strategy. • The microstructure and formation mechanism of mesoporous In{sub 2}O{sub 3} nanostructures were discussed based on the experimental results. • The as-prepared In{sub 2}O{sub 3} samples exhibited high response, short response-recovery times and good selectivity to ethanol gas. - Abstract: In this paper, large-scale mesoporous In{sub 2}O{sub 3} nanostructures were synthesized by a facile Lewis acid catalytic the furfural alcohol resin (FAR) template route for the high-yield. Their morphology and structure were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential thermal and thermogravimetry analysis (DSC-TG) and the Brunauer-Emmett-Teller (BET) approach. The as-obtained mesoporous In{sub 2}O{sub 3} nanostructures possess excellent mesoporous and network structure, which increases the contact area with the gases, it is conducive for adsorption-desorption of gas on the surface of In{sub 2}O{sub 3}. The In{sub 2}O{sub 3} particles and pores were both about 15 nm and very uniform. In gas-sensing measurements with target gases, the gas sensor based on mesoporous In{sub 2}O{sub 3} nanostructures showed a good response, short response-recovery time, good selectivity and stability to ethanol. These properties are due to the large specific surface area of mesoporous structure. This synthetic method could use as a new design concept for functional mesoporous nanomaterials and for mass production.
Magneto-optical and catalytic properties of Fe{sub 3}O{sub 4}@HA@Ag magnetic nanocomposite

Energy Technology Data Exchange (ETDEWEB)

Amir, Md., E-mail: mdamir01031001@gmail.com [Department of Chemistry, Fatih University, 34500 B.Çekmece-İstanbul, Turkey (Turkey); Bio & Nanotechnology Engineering, Faculty of Engineering, Istanbul University, 34452 Beyazıt/Fatih-İstanbul (Turkey); Güner, S. [Department of Physics, Fatih University, 34500 B.Çekmece-İstanbul, Turkey (Turkey); Yıldız, A. [Department of Textile Engineering, Namık Kemal University, 59860 Çorlu-Tekirdağ, Turkey (Turkey); Baykal, A. [Department of Chemistry, Fatih University, 34500 B.Çekmece-İstanbul, Turkey (Turkey)

2017-01-01

Fe{sub 3}O{sub 4}@HA@Ag magnetic nanocomposites (MNCs) were successfully synthesized by the simple reflux method for the removal of azo dyes from the industrial aqueous media. Fe{sub 3}O{sub 4}@HA@AgMNCs exhibited high catalytic activity to reduce MB within 20 min from the waste water. The obtained materials were characterized by the means of different techniques. Powder X-ray diffraction (XRD) analysis confirmed the single-phase of Fe{sub 3}O{sub 4} spinel structure. SEM and TEM analysis indicated that Fe{sub 3}O{sub 4}@HA@AgMNCs were nanoparticles like structure with small agglomeration. TG result showed that the products contained 9% of HA. The characteristic peaks of HA at 1601 cm{sup −1} and 1703 cm{sup −1} was observed by the means of FT-IR spectra of Fe{sub 3}O{sub 4}@HA@AgMNCs. The hysteresis (σ–H) curves revealed Fe{sub 3}O{sub 4}@HA@Ag MNCs exhibit a typical superparamagnetic characteristic with a saturation magnetization of 59.11 emu/g and measured magnetic moment is 2.45 µ{sub B}. The average magnetic particle dimension (D{sub mag}) is 13.25 nm. In accordance, the average crystallite and particle dimensions were obtained as 11.50 nm and 13.10 nm from XRD and TEM measurements, respectively. Magnetocrystalline anisotropy was offered as uniaxial and calculated effective anisotropy constant (K{sub eff}) is 2.96×10{sup 5} Erg/g. The blocking temperature was estimated as 522 K. The size-dependent saturation magnetization suggests the existence of a magnetically dead layer as 0.793 nm for Fe{sub 3}O{sub 4}@HA@Ag MNCs. The UV–vis diffuse reflectance spectroscopy (DRS) and Kubelka–Munk theory were applied to determine the optical properties of powder samples. The direct optical energy band gap (E{sub g}) values were estimated from Tauc plots between 1.62 eV and 2.12 eV. - Graphical abstract: An illustration for the fabrication of Fe{sub 3}O{sub 4}@HA@Ag MNCs. - Highlights: • The reduction of azo dye such Methylene Blue was instantly completed with
Characterization of γ- Al{sub 2}O{sub 3} nanopowders synthesized by Co-precipitation method

Energy Technology Data Exchange (ETDEWEB)

Jbara, Ahmed S., E-mail: ahmedsbhe@yahoo.com [Center for Sustainable Nanomaterials, Universiti Teknologi Malaysia, Skudai - 81310, Johor Bahru (Malaysia); Physics Department, Science College, Al-Muthanna University, Samawah - 66001 (Iraq); Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, Skudai - 81310, Johor Bahru (Malaysia); Othaman, Zulkafli [Center for Sustainable Nanomaterials, Universiti Teknologi Malaysia, Skudai - 81310, Johor Bahru (Malaysia); Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, Skudai - 81310, Johor Bahru (Malaysia); Ati, Ali A. [Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, Skudai - 81310, Johor Bahru (Malaysia); Saeed, M.A., E-mail: moalsd@gmail.com [Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, Skudai - 81310, Johor Bahru (Malaysia); Division of Science and Technology, University of Education, Township, Lahore - 54770 (Pakistan)

2017-02-15

Co-precipitation technique has been used to synthesize gamma-Al{sub 2}O{sub 3} (γ-Al{sub 2}O{sub 3}) nanopowders under annealing temperature effect. The crystalline phase and purity for the prepared powder were characterized by different spectroscopy techniques. XRD analysis confirms the gamma phase of alumina nanopowders with particle diameter ranging from 6 to 24 nm, which confirms the quantum dots formation, which is also supported by the BET measurement. The surface area of the prepared nanopowders is in the range of 109–367 m{sup 2}/g. Morphology analysis indicates that γ-Al{sub 2}O{sub 3} nanopowders are consisted of grains almost spherical in shape. Some agglomeration of nanoparticles occurs, which become more regular hexagonal shaped with the increasing annealing temperature. The small nanoparticles size and the high surface area from a simple procedure for preparing γ-Al{sub 2}O{sub 3} may make it more suitable for use as an adsorbent for malachite green. - Highlights: • Co-precipitation technique is used to synthesize gamma- Al{sub 2}O{sub 3} nanopowders. • Pure gamma- Al{sub 2}O{sub 3} phase was obtained having maximum nanoparticle size is 24 nm. • The quantum dots were formed inside powder. • High surface area of nanopowders at the low annealing temperature. • Increasing annealing temperature causes the hexagonal agglomeration shape.
The quaternary arsenide oxides Ce{sub 9}Au{sub 5-x}As{sub 8}O{sub 6} and Pr{sub 9}Au{sub 5-x}As{sub 8}O{sub 6}

Energy Technology Data Exchange (ETDEWEB)

Bartsch, Timo; Hoffmann, Rolf-Dieter; Poettgen, Rainer [Univ. Muenster (Germany). Inst. fuer Anorganische und Analytische Chemie

2016-07-01

The quaternary gold arsenide oxides Ce{sub 9}Au{sub 5-x}As{sub 8}O{sub 6} and Pr{sub 9}Au{sub 5-x}As{sub 8}O{sub 6} were synthesized from the rare earth elements (RE), rare earth oxides, arsenic and gold powder at maximum annealing temperatures of 1173 K. The structures were refined from single crystal X-ray diffractometer data: Pnnm, a=1321.64(6) pm, b=4073.0(3), c=423.96(2), wR2=0.0842, 3106 F{sup 2} values, 160 variables for Ce{sub 9}Au{sub 4.91(4)}As{sub 8}O{sub 6} and Pnnm, a=1315.01(4), b=4052.87(8), c=420.68(1) pm, wR2=0.0865, 5313 F{sup 2} values, 160 variables for Pr{sub 9}Au{sub 4.75(1)}As{sub 8}O{sub 6}. They represent a new structure type and show a further extension of pnictide oxide crystal chemistry. A complex polyanionic gold arsenide network [Au{sub 5}As{sub 8}]{sup 15-} (with some disorder in the gold substructure) is charge compensated with polycationic strands of condensed edge-sharing O rate at RE{sub 4/4} and O rate at RE{sub 4/3} tetrahedra ([RE{sub 4}O{sub 3}]{sub 2}{sup 12+}) as well as RE{sup 3+} cations in cavities.
TEA controllable preparation of magnetite nanoparticles (Fe{sub 3}O{sub 4} NPs) with excellent magnetic properties

Energy Technology Data Exchange (ETDEWEB)

Han, Chengliang, E-mail: clhan@issp.ac.cn [Department of Chemical and Material Engineering, Hefei University, Hefei 230601 (China); Zhu, Dejie [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002 (China); Wu, Hanzhao; Li, Yao; Cheng, Lu; Hu, Kunhong [Department of Chemical and Material Engineering, Hefei University, Hefei 230601 (China)

2016-06-15

A fast and controllable synthesis method for superparamagnetic magnetite nanoparticles (Fe{sub 3}O{sub 4} NPs) was developed in Fe(III)-triethanolamine (TEA) solution. The phase structure, morphology and particle size of the as-synthesized samples were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results showed that the magnetic particles were pure Fe{sub 3}O{sub 4} with mean sizes of approximately 10 nm. The used TEA has key effects on the formation of well dispersing Fe{sub 3}O{sub 4} NPs. Vibrating sample magnetometer (VSM) result indicated that the as-obtained Fe{sub 3}O{sub 4} NPs exhibited superparamagnetic behavior and the saturation magnetization (M{sub s}) was about 70 emu/g, which had potential applications in magnetic science and technology. - Highlights: • The Fe{sub 3}O{sub 4} NPs are synthesized by a simple and low-cost hydrothermal approach. • The triethanolamine (TEA) played vital roles in the formation of Fe{sub 3}O{sub 4} NPs. • Our samples exhibited superparamagnetic and excellent dispersing properties in water.
Synthesis of polycrystalline Co{sub 3}O{sub 4} nanowires with excellent ammonium perchlorate catalytic decomposition property

Energy Technology Data Exchange (ETDEWEB)

Zhou, Hai [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Lv, Baoliang, E-mail: lbl604@sxicc.ac.cn [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China); Wu, Dong; Xu, Yao [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China)

2014-12-15

Graphical abstract: Co{sub 3}O{sub 4} nanowires with excellent ammonium perchlorate catalytic decomposition property were synthesized via a methanamide-assisted hydrolysis and subsequent dissolution–recrystallization process in the presence of methanamide. - Abstract: Co{sub 3}O{sub 4} nanowires, with the length of tens of micrometers and the width of several hundred nanometers, were produced by a hydrothermal treatment and a post-anneal process. X-ray diffraction (XRD) result showed that the Co{sub 3}O{sub 4} nanowires belong to cubic crystal system. Scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) analysis indicated that the Co{sub 3}O{sub 4} nanowires, composed by single crystalline nanoparticles, were of polycrystalline nature. On the basis of time-dependent experiments, methanamide-assisted hydrolysis and subsequent dissolution–recrystallization process were used to explain the precursors' formation process of the polycrystalline Co{sub 3}O{sub 4} nanowires. The TGA experiments showed that the as-obtained Co{sub 3}O{sub 4} nanowires can catalyze the thermal decomposition of ammonium perchlorate (AP) effectively.
Dopant activation in Sn-doped Ga{sub 2}O{sub 3} investigated by X-ray absorption spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Siah, S. C., E-mail: sincheng@alum.mit.edu; Brandt, R. E.; Jaramillo, R.; Buonassisi, T., E-mail: buonassisi@mit.edu [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Lim, K. [SLAC National Accelerator Laboratory, Stanford Synchrotron Radiation Lightsource, Menlo Park, California 94025 (United States); Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States); Schelhas, L. T.; Toney, M. F. [SLAC National Accelerator Laboratory, Stanford Synchrotron Radiation Lightsource, Menlo Park, California 94025 (United States); Heinemann, M. D. [PVcomB, Helmholtz-Zentrum Berlin, 12489 Berlin (Germany); Chua, D.; Gordon, R. G. [Department of Chemistry Materials Science and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138 (United States); Wright, J.; Segre, C. U. [Physics Department and CSRRI, Illinois Institute of Technology, Chicago, Illinois 60616 (United States); Perkins, J. D. [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States)

2015-12-21

Doping activity in both beta-phase (β-) and amorphous (a-) Sn-doped gallium oxide (Ga{sub 2}O{sub 3}:Sn) is investigated by X-ray absorption spectroscopy (XAS). A single crystal of β-Ga{sub 2}O{sub 3}:Sn grown using edge-defined film-fed growth at 1725 °C is compared with amorphous Ga{sub 2}O{sub 3}:Sn films deposited at low temperature (<300 °C). Our XAS analyses indicate that activated Sn dopant atoms in conductive single crystal β-Ga{sub 2}O{sub 3}:Sn are present as Sn{sup 4+}, preferentially substituting for Ga at the octahedral site, as predicted by theoretical calculations. In contrast, inactive Sn atoms in resistive a-Ga{sub 2}O{sub 3}:Sn are present in either +2 or +4 charge states depending on growth conditions. These observations suggest the importance of growing Ga{sub 2}O{sub 3}:Sn at high temperature to obtain a crystalline phase and controlling the oxidation state of Sn during growth to achieve dopant activation.
Preparation and application of granular ZnO/Al{sub 2}O{sub 3} catalyst for the removal of hazardous trichloroethylene

Energy Technology Data Exchange (ETDEWEB)

Chen, J.-C. [Department of Environmental Engineering, Hung-Kuang University, No. 34, Chung-Chie Road, Shalu, Taichung County, Taiwan 43302 (China)]. E-mail: jcchen@sunrise.hk.edu.tw; Tang, C.-T. [Department of Environmental Engineering, Hung-Kuang University, No. 34, Chung-Chie Road, Shalu, Taichung County, Taiwan 43302 (China)

2007-04-02

Trichloroethylene (TCE) is a volatile and nerve-toxic liquid, which is widely used in many industries as an organic solvent. Without proper treatment, it will be volatilized into the atmosphere easily and hazardous to the human health and the environment. This study tries to prepare granular ZnO/Al{sub 2}O{sub 3} catalyst by a modified oil-drop sol-gel process incorporated the incipient wetness impregnation method and estimates its performance on the catalytic decomposition of TCE. The effects of different preparation and operation conditions are also investigated. Experimental results show that the granular ZnO/Al{sub 2}O{sub 3} catalyst has good catalytic performance on TCE decomposition and the conversion of TCE is 98%. ZnO/Al{sub 2}O{sub 3}(N) catalyst has better performance than ZnO/Al{sub 2}O{sub 3}(O) at high temperature. Five percent of active metal concentration and 550 deg. C calcination temperature are the better and economic preparation conditions, and the optimum operation temperature and space velocity are 450 deg. C and 18,000 h{sup -1}, respectively. The conversions of TCE are similar and all higher than 90% as the oxygen concentration in feed gas is higher than 5%. By Fourier transform infrared spectrography (FT-IR) analyses, the major reaction products in the catalytic decomposition of TCE are HCl and CO{sub 2}. The Brunauer-Emmett-Teller (BET) surface areas of catalysts are significantly decreased as the calcination temperature is higher than 550 deg. C due to the sintering of catalyst materials, as well as the reaction temperature is higher than 150 deg. C due to the accumulations of reaction residues on the surfaces of catalysts. These results are also demonstrated by the results of scanning electron micrography (SEM) and energy disperse spectrography (EDS)
Investigation on compression behavior of TZM and La{sub 2}O{sub 3} doped TZM Alloys at high temperature

Energy Technology Data Exchange (ETDEWEB)

Hu, Ping, E-mail: huping1985@126.com [School of Metallurgy Engineering, Xi’an University of Architecture and Technology, Xi’an 710055 (China); Zhou, Yuhang; Chang, Tian; Yu, Zhitao; Wang, Kuaishe; Yang, Fan; Hu, Boliang [School of Metallurgy Engineering, Xi’an University of Architecture and Technology, Xi’an 710055 (China); Cao, Weicheng [Jinduicheng Molybdenum Co., Ltd, Xi’an 710077 (China); Yu, Hailiang [School of Mechanical, Materials, Mechatronic Engineering, University of Wollongong, Wollongong, NSW 2500 (Australia)

2017-02-27

Mechanical properties of Titanium-zirconium-molybdenum (TZM) and La{sub 2}O{sub 3} doped TZM alloys under compression were tested at 1000 °C and 1200 °C. Microstructure of TZM and La{sub 2}O{sub 3} doped TZM alloys after compressing was characterized by scanning electron microscopy. The effects on La{sub 2}O{sub 3} doping on the high temperature deformation behavior and microstructure evolution of the TZM alloy were analyzed. Results show that La{sub 2}O{sub 3} doping can refine the grain size of TZM alloy. La{sub 2}O{sub 3} doping changes fracture model of TZM alloy. TZM alloy exhibits mainly intergranular fracture, while the La{sub 2}O{sub 3} doped TZM alloy exhibits both intergranular and transgranular fracture mode.
Interparticle interactions of FePt core and Fe{sub 3}O{sub 4} shell in FePt/Fe{sub 3}O{sub 4} magnetic nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Akbari, Hossein, E-mail: Akbari.ph@iauardabil.ac.ir [Department of Physics, Ardabil Branch, Islamic Azad University, Ardabil (Iran, Islamic Republic of); Zeynali, Hossein [Department of Physics, Kashan Branch, Islamic Azad University, Kashan (Iran, Islamic Republic of); Bakhshayeshi, Ali [Department of Physics, Mashhad Branch, Islamic Azad University, Mashhad (Iran, Islamic Republic of)

2016-02-22

Monodisperse FePt nanoparticles were successfully synthesized using simple wet chemical method. Fe{sub 3}O{sub 4} was used as a magnetic shell around each FePt nanoparticles. In FePt/Fe{sub 3}O{sub 4} core/shell system, core thickness is 2 nm and shell thickness varies from zero to 2.5 nm. A theoretical model presented to calculate the shell thickness dependence of Coercivity. Presented model is compared with the results from Stoner–Wohlfarth model to interpret the shell thickness dependence of Coercivity in FePt/Fe{sub 3}O{sub 4} core/shell nanoparticles. There is a difference between the results from Stoner–Wohlfarth model and experimental data when the shell thickness increases. In the presented model, the effects of interparticle exchange and random magneto crystalline anisotropy are added to the previous models of magnetization reversal for core/shell nanostructures in order to achieve a better agreement with experimental data. For magnetic shells in FePt/Fe{sub 3}O{sub 4} core/shell, effective coupling between particles increases with increasing shell thickness which leads to Coercivity destruction for stronger couplings. According to the boundary conditions, in the harder regions with higher exchange stiffness, there is small variation in magnetization and so the magnetization modes become more localized. We discussed both localized and non-localized magnetization modes. For non-zero shell thickness, non-localized modes propagate in the soft phase which effects the quality of particle exchange interactions. - Highlights: • Monodisperse FePt nanoparticles were successfully synthesized using simple wet chemical method. • Fe{sub 3}O{sub 4} was used as a magnetic shell around each FePt nanoparticles. • A theoretical model presented to calculate the shell thickness dependence of Coercivity. • Magnetic shells increase effective coupling between particles with increasing shell thickness. • Magnetization modes are more localized in the regions with
Hydrothermal synthesis and characterization of the praseodymium borate-nitrate Pr[B{sub 5}O{sub 8}(OH)(H{sub 2}O){sub 0.87}]NO{sub 3}.2H{sub 2}O

Energy Technology Data Exchange (ETDEWEB)

Ortner, Teresa S.; Huppertz, Hubert [Innsbruck Univ. (Austria). Inst. fuer Allgemeine, Anorganische und Theoretische Chemie

2017-10-01

The praseodymium borate-nitrate Pr[B{sub 5}O{sub 8}(OH)(H{sub 2}O){sub 0.87}]NO{sub 3}.2H{sub 2}O was obtained in a hydrothermal synthesis. It crystallizes monoclinically in the space group P2{sub 1}/n (no. 14) with four formula units (Z=4) and unit cell parameters of a=641.9(3), b=1551.8(7), c=1068.4(5) pm, with β=90.54(2) yielding V=1.0643(8) nm{sup 3}. The defect variant constitutes the missing member in the series of isostructural, early rare earth borate-nitrates of the composition RE[B{sub 5}O{sub 8}(OH)(H{sub 2}O){sub x}]NO{sub 3}.2H{sub 2}O [RE=La (x=0; 1), Ce (x=1), Nd (x=0.85), Sm (x=0)]. In addition to powder and single-crystal X-ray diffraction data, the novel borate-nitrate was characterized through IR and Raman spectroscopy.
Al{sub 2}O{sub 3}:Cr{sup 3+} microfibers by hydrothermal route: Luminescence properties

Energy Technology Data Exchange (ETDEWEB)

Liu, Dianguang [School of Materials Science and Engineering, Shaanxi University of Science and Technology, Xi’an 710021 (China); Zhu, Zhenfeng, E-mail: zhuzf@sust.edu.cn [School of Materials Science and Engineering, Shaanxi University of Science and Technology, Xi’an 710021 (China); Liu, Hui; Zhang, Zhengyang; Zhang, Yanbin; Li, Gege [School of Materials Science and Engineering, Shaanxi University of Science and Technology, Xi’an 710021 (China)

2012-09-15

Highlights: ► Uniform Al{sub 2}O{sub 3}:Cr{sup 3+} microfibers were synthesized via a hydrothermal route and thermal decomposition. ► The length and diameter of Al{sub 2}O{sub 3}:Cr{sup 3+} microfibers were about 3–9 μm and 300 nm, respectively. ► Al{sub 2}O{sub 3}:Cr{sup 3+} microfibers presented a broad R band at 696 nm when excited at 400 nm. ► It is shown that the 0.07 mol% of doping concentration of Cr{sup 3+} ions in α-Al{sub 2}O{sub 3}:Cr{sup 3+} is optimum. ► Critical distance between Cr{sup 3+} ions for energy transfer was determined to be 38 Å. -- Abstract: Uniform Al{sub 2}O{sub 3}:Cr{sup 3+} microfibers were synthesized by using a hydrothermal route and thermal decomposition of a precursor of Cr{sup 3+} doped ammonium aluminum hydroxide carbonate (denoted as AAHC), and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), photoluminescence (PL) spectra and decay curves. XRD indicated that Cr{sup 3+} doped samples calcined at 1473 K were the most of α-Al{sub 2}O{sub 3} phase. SEM showed that the length and diameter of these Cr{sup 3+} doped alumina microfibers were about 3–9 μm and 300 nm, respectively. PL spectra showed that the Al{sub 2}O{sub 3}:Cr{sup 3+} microfibers presented a broad R band at 696 nm. It is shown that the 0.07 mol% of doping concentration of Cr{sup 3+} ions in α-Al{sub 2}O{sub 3}:Cr{sup 3+} was optimum. According to Dexter's theory, the critical distance between Cr{sup 3+} ions for energy transfer was determined to be 38 Å. It is found that the curve followed the single-exponential decay.
Calcite veins of the Stripa granite (Sweden) as records of the origin of the ground waters and their interactions with the granitic body

International Nuclear Information System (INIS)

Clauer, N.; Fritz, B.; Frape, S.K.

1989-01-01

A Sr isotopic study combined with stable isotope determinations (δ 18 O and δ 13 C), petrographic observations and speciation calculations suggests that the Stripa granite (Sweden) contains at least three different types of calcite veins. One type with δ 18 O = -18 to -24 per-thousand (PDB) and 87 Sr/ 86 Sr = 0.7814 to 1.0696 probably formed at temperatures above 200 degree C, together with chlorite and epidote, during one or two metamorphic events which are recorded in the Rb-Sr systematics of some minerals of the granite at 1.4 and 0.8 Ga. Another type with δ 18 O = -12 to -18 per-thousand (PDB) and 87 Sr/ 86 Sr = 0.7406 to 0.7536 and mainly associated with chlorite, is most likely in equilibrium with the present day ground waters, which probably have reacted with the fracture minerals of the granitic body for a long time without any supply of external fluids. The third type of calcite with δ 18 C = -12 to -18 per-thousand (PDB), δ 13 C = -5 to -45 per-thousand (PDB) and 87 Sr/ 86 Sr = 0.7266 to 0.7406, could have formed from reactions involving methane oxidation or sulfate reduction in the presence of bacteria
Effects of Y{sub 2}O{sub 3}/CeO{sub 2} co-doping on microwave dielectric properties of Ba(Co{sub 0.6}Zn{sub 38}){sub 1/3}Nb{sub 2/3}O{sub 3} ceramics

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yuqin; Zhou, Xiaohua, E-mail: 1250590698@qq.com; Yang, Xinshi; Sun, Chengli; Yang, Fan; Chen, Hetuo

2016-09-15

The effects of CeO{sub 2}/Y{sub 2}O{sub 3} co-doping on the microstructure and microwave dielectric properties of Ba(Co{sub 0.6}Zn{sub 0.38}){sub 1/3}Nb{sub 2/3}O{sub 3}-xA-xB (x = 0,1,2,3,4,6; A = 0.1204 wt%Y{sub 2}O{sub 3}; B = 0.1 wt%CeO{sub 2}) ceramics prepared by the conventional solid-state route technique were investigated. The X-ray diffraction (XRD) results presented that all the well sintered samples exhibited the main phase BaZn{sub 0.33}Nb{sub 0.67}O{sub 3}−Ba{sub 3}CoNb{sub 2}O{sub 9}. A certain amount of Ba{sub 8}CoNb{sub 6}O{sub 24} surface secondary phase and minority phase of Ba{sub 5}Nb{sub 4}O{sub 15} were also observed in all sintered ceramics. The 1:2 B-site cation ordering degree was found to influenced by the substitution of Y{sup 3+} and Ce{sup 4+} in the crystal lattice, especially for x = 0.02. Then the scanning electron microscopy (SEM) picture of the optimally well-sintered (1350 °C for 20 h) ceramic has shown a dense microstructure. Although the ε{sub r} almost kept unchanged, appropriate doping content would greatly improve the Q × f value. Meanwhile, the τ{sub f} value first declined and then increased with increasing x. At last, the excellent microwave dielectric properties of ε{sub r} = 36.09, Q × f = 72006 GHz, τ{sub f} = 3.35 ppm/ºC were obtained for the ceramic with x = 0.02 sintered in air at 1350 °C for 20 h. - Graphical abstract: Fig. SEM images of as-sintered Ba(Co{sub 0.6}Zn{sub 0.38}){sub 1/3}Nb{sub 2/3}O{sub 3}-xA-Xb (A = 0.1204 wt%Y{sub 2}O{sub 3}; B = 0.1 wt%CeO{sub 2)}ceramics: (a) x = 0,(b) x = 0.01,(c) x = 0.02,(d) x = 0.03, (e) x = 0.04,(f) x = 0.06. The images confirmed the presences of two phases on the surface of the ceramics, plate-shaped grains (Ba{sub 8}(C{sub O},Zn){sub 1}Nb{sub 6}O{sub 24}phase) and needle-shaped grains (Ba{sub 3}(Co{sub 0.6}Zn{sub 0.38}){sub 1}Nb{sub 2}O{sub 9} phase). As a small content of CeO{sub 2}/Y{sub 2}O{sub 3} (x = 0.01–0.04) was codoped into the BCZN ceramics, the
Preparation of transparent Cu{sub 2}Y{sub 2}O{sub 5} thin films by RF magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Chiu, Te-Wei, E-mail: tewei@ntut.edu.tw; Chang, Chih-Hao; Yang, Li-Wei; Wang, Yung-Po

2015-11-01

Highlights: • Cu{sub 2}Y{sub 2}O{sub 5} thin films were prepared by RF magnetron sputtering. • Cu{sub 2}Y{sub 2}O{sub 5} thin films have high transmittance and antibacterial properties. • Mechanical properties of Cu{sub 2}Y{sub 2}O{sub 5} thin films were investigated. - Abstract: Cu{sub 2}Y{sub 2}O{sub 5} thin films were deposited on non-alkali glass substrates by RF magnetron sputtering. Its crystal structure, microstructure, optical property, mechanical property, and antibacterial activity were investigated by grazing-incidence X-ray diffraction, transmittance spectra, nanoindenter, and antibiotics test, respectively. A single-phase of Cu{sub 2}Y{sub 2}O{sub 5} was obtained while annealing at 700 °C in air and its optical transparency was >80% in the visible region. The hardness and elastic modulus of the film were 6.7 GPa and 82 GPa, respectively. Antibiotics testing result revealed that Cu{sub 2}Y{sub 2}O{sub 5} surface had a superior antibacterial performance even at a dark environment. Therefore, Cu{sub 2}Y{sub 2}O{sub 5} is a promising novel transparent antibacterial hard coating material.
Synthesis, structure, and polymorphism of A{sub 3}LnSi{sub 2}O{sub 7} (A=Na, K; Ln=Sm, Ho, Yb)

Energy Technology Data Exchange (ETDEWEB)

Latshaw, Allison M.; Yeon, Jeongho; Smith, Mark D.; Loye, Hans-Conrad zur, E-mail: zurloye@mailbox.sc.edu

2016-03-15

Four new members of the A{sub 3}LnSi{sub 2}O{sub 7} family, K{sub 3}SmSi{sub 2}O{sub 7}, Na{sub 3}HoSi{sub 2}O{sub 7}, and two polymorphs of Na{sub 3}YbSi{sub 2}O{sub 7}, are reported. K{sub 3}SmSi{sub 2}O{sub 7} crystallizes in the hexagonal space group P6{sub 3}/mcm, Na{sub 3}HoSi{sub 2}O{sub 7} and Na{sub 3}YbSi{sub 2}O{sub 7} crystallize in the hexagonal space group P6{sub 3}/m, and Na{sub 3}YbSi{sub 2}O{sub 7} crystallizes in the trigonal space group P31c. The Na{sub 3}YbSi{sub 2}O{sub 7} composition that crystallizes in P31c is a new structure type. The magnetic properties for the Ho and Yb analogs are reported. - Graphical abstract: The different structure types and polymorphs of the A{sub 3}LnSi{sub 2}O{sub 7} family reported. - Highlights: • Four new members of the A{sub 3}LnSi{sub 2}O{sub 7} family are presented. • Na{sub 3}YbSi{sub 2}O{sub 7} is reported as two polymorphs, one is a new structure type. • Crystals synthesized out of molten fluoride fluxes.
Detoxification and repair process of ozone injury: From O{sub 3} uptake to gene expression adjustment

Energy Technology Data Exchange (ETDEWEB)

Castagna, A., E-mail: castagna@agr.unipi.i [Department of Agricultural Chemistry and Biotechnology, University of Pisa, Via del Borghetto 80, 56124 Pisa (Italy); Ranieri, A., E-mail: aranieri@agr.unipi.i [Department of Agricultural Chemistry and Biotechnology, University of Pisa, Via del Borghetto 80, 56124 Pisa (Italy)

2009-05-15

Plants react to O{sub 3} threat by setting up a variety of defensive strategies involving the co-ordinated modulation of stress perception, signalling and metabolic responses. Although stomata largely controls O{sub 3} uptake, differences in O{sub 3} tolerance cannot always be ascribed to changes in stomatal conductance but cell protective and repair processes should be taken into account. O{sub 3}-driven ROS production in the apoplast induces a secondary, active, self-propagating generation of ROS, whose levels must be finely tuned, by many enzymatic and non-enzymatic antioxidant systems, to induce gene activation without determining uncontrolled cell death. Additional signalling molecules, as ethylene, jasmonic and salicylic acid are also crucial to determine the spreading and the containment of leaf lesions. The main recent results obtained on O{sub 3} sensing, signal transduction, ROS formation and detoxification mechanisms are here discussed. - A dissection of the complex network of interacting mechanisms which determine the cell fate under ozone stress.

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