Tracing contamination sources in soils with Cu and Zn isotopic ratios

International Nuclear Information System (INIS)

Fekiacova, Z.; Cornu, S.; Pichat, S.

2015-01-01

Copper (Cu) and zinc (Zn) are naturally present and ubiquitous in soils and are important micronutrients. Human activities contribute to the input of these metals to soils in different chemical forms, which can sometimes reach a toxic level for soil organisms and plants. Isotopic signatures could be used to trace sources of anthropogenic Cu and Zn pollution. The aim of this paper is to determine whether it is possible to identify (i) Cu and Zn contamination in soils and their sources, on the basis of their isotopic signatures, and (ii) situations that are a priori favorable or not for tracing Cu and Zn pollution using the isotopic approach. Therefore, we compiled data from the literature on Cu and Zn isotopes in soils, rocks and pollutants and added to this database the results of our own research. As only a few studies have dealt with agricultural contamination, we also studied a soil toposequence from Brittany, France, that experienced spreading of pig slurry for tens of years. In the surface horizons of the natural soils, the δ 65 Cu values vary from − 0.15 to 0.44‰ and the δ 66 Zn from − 0.03 to 0.43‰. Furthermore, vertical variations along soil profiles range from − 0.95 to 0.44‰ for δ 65 Cu and from − 0.53 to 0.64‰ for δ 66 Zn values. We concluded that pedogenetic processes can produce isotopic fractionation, yet, it is not always discernible and can be overprinted by an exogenous isotopic signature. Furthermore, some contaminants are enriched in heavy Cu or in light Zn compared to the rock or soil, but no generalization can be made. The anthropogenic inputs can be identified based on stable Cu and Zn isotope ratios if the isotope ratios of the sources are different from those of the soil, which needs to be tested for each individual case. - Highlights: • Pedogenetic processes produce some Cu and Zn isotope fractionation. • Pollution with distinct isotopic signatures can be traced using Cu and Zn isotopes. • Tracing of the metal

Tracing contamination sources in soils with Cu and Zn isotopic ratios.

Science.gov (United States)

Fekiacova, Z; Cornu, S; Pichat, S

2015-06-01

Copper (Cu) and zinc (Zn) are naturally present and ubiquitous in soils and are important micronutrients. Human activities contribute to the input of these metals to soils in different chemical forms, which can sometimes reach a toxic level for soil organisms and plants. Isotopic signatures could be used to trace sources of anthropogenic Cu and Zn pollution. The aim of this paper is to determine whether it is possible to identify (i) Cu and Zn contamination in soils and their sources, on the basis of their isotopic signatures, and (ii) situations that are a priori favorable or not for tracing Cu and Zn pollution using the isotopic approach. Therefore, we compiled data from the literature on Cu and Zn isotopes in soils, rocks and pollutants and added to this database the results of our own research. As only a few studies have dealt with agricultural contamination, we also studied a soil toposequence from Brittany, France, that experienced spreading of pig slurry for tens of years. In the surface horizons of the natural soils, the δ(65)Cu values vary from -0.15 to 0.44‰ and the δ(66)Zn from -0.03 to 0.43‰. Furthermore, vertical variations along soil profiles range from -0.95 to 0.44‰ for δ(65)Cu and from -0.53 to 0.64‰ for δ(66)Zn values. We concluded that pedogenetic processes can produce isotopic fractionation, yet, it is not always discernible and can be overprinted by an exogenous isotopic signature. Furthermore, some contaminants are enriched in heavy Cu or in light Zn compared to the rock or soil, but no generalization can be made. The anthropogenic inputs can be identified based on stable Cu and Zn isotope ratios if the isotope ratios of the sources are different from those of the soil, which needs to be tested for each individual case. Copyright © 2015 Elsevier B.V. All rights reserved.

Structural and optical properties of nanocrystalline ZnS and ZnS:Al films

Science.gov (United States)

Hurma, T.

2018-06-01

ZnS and ZnS:Al films have been deposited by ultrasonic spray pyrolysis (USP) method. Three different atomic ratios of aluminium were used as the dopant element. The effects of aluminum incorporation on structural and optical properties of the ZnS films have been investigated. The XRD analysis showed that the cubic structure of the ZnS was not much affected by Al doping. The crystal size of the films decreased, as the Al ratio increased. Al incorporation caused an increase in the intensity of ZnS films' peaks observed in Raman spectra and nearly symmetrical peaks were observed. Al doping caused a small decrease in optical band gap of the ZnS film. The coating of ZnS:Al films on the surface was quite good and there were not any deformation in their crystallization levels. Reflectance values of films are about 5% in the visible region but a little decrease is seen with aluminum doping. We can say that Al doping tends to improve the optical properties of the ZnS:Al films when compared with the undoped ZnS.

Lattice location of the group V elements Sb, As, and P in ZnO

CERN Document Server

Wahl, Ulrich; Mendonça, Tânia; Decoster, Stefan

2010-01-01

Modifying the properties of ZnO by means of incorporating antimony, arsenic or phosphorus impurities is of interest since these group V elements have been reported in the literature among the few successful p-type dopants in this technologically promising II-VI compound. The lattice location of ion-implanted Sb, As, and P in ZnO single crystals was investigated by means of the electron emission channeling technique using the radioactive isotopes $^{124}$Sb, $^{73}$As and $^{33}$P and it is found that they preferentially occupy substitutional Zn sites while the possible fractions on substitutional O sites are a few percent at maximum. The lattice site preference is understandable from the relatively large ionic size of the heavy mass group V elements. Unfortunately the presented results cannot finally settle the interesting issue whether substitutional Sb, As or P on oxygen sites or Sb$_{Zn}$−2V$_{Zn}$, As$_{Zn}$−2V$_{Zn}$ or P$_{Zn}$−2V$_{Zn}$ complexes (as suggested in the literature) are responsible f...

Evaluation of Fe and Zn/Cu ratio in serum of patients with sickle cell anemia by total reflection X-ray fluorescence using synchrotron radiation

Energy Technology Data Exchange (ETDEWEB)

Canellas, Catarine G.L.; Leitao, Roberta G.; Lopes, Ricardo T., E-mail: catarine@lin.ufrj.b, E-mail: ricardo@lin.ufrj.b [Universidade Federal do Rio de Janeiro (PEN/COPPE/UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-Graduacao de Engenharia. Programa de Engenharia Nuclear. Lab. de Instrumentaco Nuclear; Carvalho, Silvia M.F., E-mail: silvia@hemorio.rj.gov.b [State Institute of Hematology Arthur de Siqueira Cavalcanti (HEMORIO), Rio de Janeiro, RJ (Brazil); Bellido, Alfredo Victor B., E-mail: alfredo@ien.gov.b [Federal Fluminense University (UFF), Niteroi, RJ (Brazil). Chemistry Inst.; Anjos, Marcelino J., E-mail: marcelin@lin.ufrj.b [State University of Rio de Janeiro (UERJ), RJ (Brazil). Physics Inst.

2011-07-01

Sickle cell anemia (SCA) is a blood disorder that affects hemoglobin, the protein found in red blood cells that help carry oxygen throughout the body. In this work we have analyzed serum samples from patients with SCA by using total reflection X-ray fluorescence using synchrotron radiation (SRTXRF). The SRTXRF measurements were performed at the X-ray fluorescence beamline at Brazilian National Synchrotron Light Laboratory (LNLS), in Campinas, Sao Paulo using a polychromatic beam. We have studied forty-three patients aged 18-50 years old, suffering from SCA and Sixty healthy volunteers aged 18-60 years old. It was possible to determine the concentrations of the following elements: P, S, Cl, K, Ca, Fe, Cu, Zn, Br and Rb. Student's t-test was applied in order to check whether the two populations (CG x SCA) had the same mean values. It was observed that elemental concentration of P, Cl, K, Fe, Cu, Zn and Br differed significantly ({alpha} = 0.05) between groups of healthy subjects and SCA. The concentrations of K, Fe and Cu in the serum samples of patients with SCA were larger 15%, 120 % and 20 %, respectively, when compared with the CG. On the other hand, the concentrations of P (-20 %), Cl (-6 %), Zn (-25 %) and Br (-22 %) were smaller than the values determined for the control group. The serum level Cu/Zn ratio was significantly higher (60%) in the serum samples of patients with SCA group than the CG. So, the Cu/Zn ratio can be used as an adjuvant index in enhancement for diagnosis of SCA. There are evidences of an association among Fe, Cu, Zn and Cu/Zn in the SCA pathogenesis process. (author)

Role of VI/II ratio on the growth of ZnO nanostructures using chemical bath deposition

Energy Technology Data Exchange (ETDEWEB)

Urgessa, Z.N., E-mail: zelalem.urgessa@nmmu.ac.za [Department of Physics, P.O. Box 77000, Nelson Mandela Metropolitan University, Port Elizabeth 6031 (South Africa); Oluwafemi, O.S. [Department of Chemistry and Chemical Technology, Walter Sisulu University, Mthatha Campus, Private Bag XI, 5117 (South Africa); Botha, J.R. [Department of Physics, P.O. Box 77000, Nelson Mandela Metropolitan University, Port Elizabeth 6031 (South Africa)

2012-05-15

In this paper the growth process and morphological evolution of ZnO nanostructures were investigated in a series of experiments using chemical bath deposition. The experimental results indicate that the morphological evolution depends on the reaction conditions, particularly on OH{sup -} to Zn{sup 2+} ratio (which directly affects the pH). For low VI/II ratios, quasi-spherical nanoparticles of an average diameter 30 nm are obtained, whereas for larger VI/II ratios, nanorods with an average diameter less than 100 nm are produced, which indicates that by systematically controlling the VI/II ratio, it is possible to produce different shapes and sizes of ZnO nanostructures. A possible mechanism for the nanostructural change of the as-synthesized ZnO from particle to rod was elucidated based on the relative densities of H{sup +} and OH{sup -} in the solution.

Role of VI/II ratio on the growth of ZnO nanostructures using chemical bath deposition

International Nuclear Information System (INIS)

Urgessa, Z.N.; Oluwafemi, O.S.; Botha, J.R.

2012-01-01

In this paper the growth process and morphological evolution of ZnO nanostructures were investigated in a series of experiments using chemical bath deposition. The experimental results indicate that the morphological evolution depends on the reaction conditions, particularly on OH − to Zn 2+ ratio (which directly affects the pH). For low VI/II ratios, quasi-spherical nanoparticles of an average diameter 30 nm are obtained, whereas for larger VI/II ratios, nanorods with an average diameter less than 100 nm are produced, which indicates that by systematically controlling the VI/II ratio, it is possible to produce different shapes and sizes of ZnO nanostructures. A possible mechanism for the nanostructural change of the as-synthesized ZnO from particle to rod was elucidated based on the relative densities of H + and OH − in the solution.

Comparison of trace element contamination levels (Cu, Zn, Fe, Cd ...

African Journals Online (AJOL)

SERVER

2008-03-18

Mar 18, 2008 ... Chemical analysis of the trace elements in the soft tissues. The trace elements of interest (Cu, Zn, Fe, Pb, Cd) were then determined in the digested solutions, using Thermoelemental type. M6 brand of an atomic absorption Spectrometer equipped with a flame operated atomisation system and a deuterium ...

Compositional ratio effect on the surface characteristics of CuZn thin films

Science.gov (United States)

Choi, Ahrom; Park, Juyun; Kang, Yujin; Lee, Seokhee; Kang, Yong-Cheol

2018-05-01

CuZn thin films were fabricated by RF co-sputtering method on p-type Si(100) wafer with various RF powers applied on metallic Cu and Zn targets. This paper aimed to determine the morphological, chemical, and electrical properties of the deposited CuZn thin films by utilizing a surface profiler, atomic force microscopy (AFM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), UV photoelectron spectroscopy (UPS), and a 4-point probe. The thickness of the thin films was fixed at 200 ± 8 nm and the roughness of the thin films containing Cu was smaller than pure Zn thin films. XRD studies confirmed that the preferred phase changed, and this tendency is dependent on the ratio of Cu to Zn. AES spectra indicate that the obtained thin films consisted of Cu and Zn. The high resolution XPS spectra indicate that as the content of Cu increased, the intensities of Zn2+ decreased. The work function of CuZn thin films increased from 4.87 to 5.36 eV. The conductivity of CuZn alloy thin films was higher than pure metallic thin films.

Study of new sheep bone and Zn/Ca ratio around TiAlV screw: PIXE RBS analysis

Science.gov (United States)

Guibert, G.; Munnik, F.; Langhoff, J. D.; Von Rechenberg, B.; Buffat, Ph. A.; Laub, D.; Faber, L.; Ducret, F.; Gerber, I.; Mikhailov, S.

2008-03-01

This study reports on in vivo particle induced X-ray emission (PIXE) measurements combined with Rutherford backscattering spectroscopy (RBS) analyses of new remodeled sheep bone formed around TiAlV screws. The implants (screws) were anodized by a modified TiMax™ process. The interface between the implant and the bone was carefully investigated. [Zn]/[Ca] in-depth composition profiles as well as Ca, Fe elemental maps were recorded. The thickness of new bone formed around the screw reached 300-400 μm. Osteon and Osteoid phases were identified in the new bone. A higher [Zn]/[Ca] ratio was observed in the new bone as compared to the mature bone. Blood vessels were observed in the bone in close contact with the screw. This study shows the potential of ion beam analysis for biological and biomedical characterization.

Study of new sheep bone and Zn/Ca ratio around TiAlV screw: PIXE-RBS analysis

International Nuclear Information System (INIS)

Guibert, G.; Munnik, F.; Langhoff, J.D.; Von Rechenberg, B.; Buffat, Ph.A.; Laub, D.; Faber, L.; Ducret, F.; Gerber, I.; Mikhailov, S.

2008-01-01

This study reports on in vivo particle induced X-ray emission (PIXE) measurements combined with Rutherford backscattering spectroscopy (RBS) analyses of new remodeled sheep bone formed around TiAlV screws. The implants (screws) were anodized by a modified TiMax TM process. The interface between the implant and the bone was carefully investigated. [Zn]/[Ca] in-depth composition profiles as well as Ca, Fe elemental maps were recorded. The thickness of new bone formed around the screw reached 300-400 μm. Osteon and Osteoid phases were identified in the new bone. A higher [Zn]/[Ca] ratio was observed in the new bone as compared to the mature bone. Blood vessels were observed in the bone in close contact with the screw. This study shows the potential of ion beam analysis for biological and biomedical characterization

The origin of volatile element depletion in early solar system material: Clues from Zn isotopes in chondrules

Science.gov (United States)

Pringle, Emily A.; Moynier, Frédéric; Beck, Pierre; Paniello, Randal; Hezel, Dominik C.

2017-06-01

Volatile lithophile elements are depleted in the different planetary materials to various degrees, but the origin of these depletions is still debated. Stable isotopes of moderately volatile elements such as Zn can be used to understand the origin of volatile element depletions. Samples with significant volatile element depletions, including the Moon and terrestrial tektites, display heavy Zn isotope compositions (i.e. enrichment of 66Zn vs. 64Zn), consistent with kinetic Zn isotope fractionation during evaporation. However, Luck et al. (2005) found a negative correlation between δ66Zn and 1/[Zn] between CI, CM, CO, and CV chondrites, opposite to what would be expected if evaporation caused the Zn abundance variations among chondrite groups. We have analyzed the Zn isotope composition of multiple samples of the major carbonaceous chondrite classes: CI (1), CM (4), CV (2), CO (4), CB (2), CH (2), CK (4), and CK/CR (1). The bulk chondrites define a negative correlation in a plot of δ66Zn vs 1/[Zn], confirming earlier results that Zn abundance variations among carbonaceous chondrites cannot be explained by evaporation. Exceptions are CB and CH chondrites, which display Zn systematics consistent with a collisional formation mechanism that created enrichment in heavy Zn isotopes relative to the trend defined by CI-CK. We further report Zn isotope analyses of chondrite components, including chondrules from Allende (CV3) and Mokoia (CV3), as well as an aliquot of Allende matrix. All chondrules are enriched in light Zn isotopes (∼500 ppm on 66Zn/64Zn) relative to the bulk, contrary to what would be expected if Zn were depleted during evaporation, on the other hand the matrix has a complementary heavy isotope composition. We report sequential leaching experiments in un-equilibrated ordinary chondrites, which show sulfides are isotopically heavy compared to silicates and the bulk meteorite by ca. +0.65 per mil on 66Zn/64Zn. We suggest isotopically heavy sulfides were

Copper to Zinc Ratio as Disease Biomarker in Neonates with Early-Onset Congenital Infections

Science.gov (United States)

Wisniewska, Monika; Cremer, Malte; Wiehe, Lennart; Becker, Niels-Peter; Rijntjes, Eddy; Martitz, Janine; Renko, Kostja; Bührer, Christoph; Schomburg, Lutz

2017-01-01

Copper (Cu) and zinc (Zn) are essential trace elements for regular development. Acute infections alter their metabolism, while deficiencies increase infection risks. A prospective observational case-control study was conducted with infected (n = 21) and control (n = 23) term and preterm newborns. We analyzed trace element concentrations by X-ray fluorescence, and ceruloplasmin (CP) by Western blot. Median concentration of Cu at birth (day 1) was 522.8 [387.1–679.7] μg/L, and Zn was 1642.4 ± 438.1 μg/L. Cu and Zn correlated positively with gestational age in control newborns. Cu increased in infected newborns from day 1 to day 3. CP correlated positively to Cu levels at birth in both groups and on day 3 in the group of infected neonates. The Cu/Zn ratio was relatively high in infected newborns. Interleukin (IL)-6 concentrations on day 1 were unrelated to Cu, Zn, or the Cu/Zn ratio, whereas C-reactive protein (CRP) levels on day 3 correlated positively to the Cu/Zn -ratio at both day 1 and day 3. We conclude that infections affect the trace element homeostasis in newborns: serum Zn is reduced, while Cu and CP are increased. The Cu/Zn ratio combines both alterations, independent of gestational age. It may, thus, constitute a meaningful diagnostic biomarker for early-onset infections. PMID:28358335

Elaboration and optical properties of type-II ZnTe on ZnSe heterostructures

Energy Technology Data Exchange (ETDEWEB)

Najjar, Rita, E-mail: rita.najjar@cea.f [CEA-CNRS group ' Nanophysique et semiconducteurs' , Institut NEEL-CNRS, BP166, 25 rue des martyrs, 38042 Grenoble Cedex 9 (France); Andre, Regis; Besombes, Lucien; Bougerol, Catherine; Tatarenko, Serge; Mariette, Henri [CEA-CNRS group ' Nanophysique et semiconducteurs' , Institut NEEL-CNRS, BP166, 25 rue des martyrs, 38042 Grenoble Cedex 9 (France)

2009-11-25

Special growth conditions are presented in this work, in order to produce ZnTe/ZnSe type-II quantum dots and preserve them during the capping stage. A detailed study emphasizes the high sensitivity of the sample structure to Se/Zn ratio as opposed to other growth parameters. It is shown that nominally identical samples can evolve into two-dimensional quantum well or quantum dot plane, depending on which element is in excess. Transmission electron microscopy, atomic force microscopy and optical characterizations evidence this phenomenon.

Enrichment ratios of elements in selected plant species from black coal mine dumps in Lower Silesia (Poland)

Energy Technology Data Exchange (ETDEWEB)

Samecka-Cymerman, A.; Kempers, A.J. [University of Wroclaw, Wroclaw (Poland)

2003-07-01

Concentration of the metals Al, Ba, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sr, Zn and V as well as N, P, K, Ca, Mg, Fe and S were measured in soils and in two tree species (leaves of Betula pendula and Salix caprea) and two herbs (whole above-ground parts of Solidago canadensis and Tanacetum vulgare) sampled from dumps in the Walbrzych coal mine area (Lower Silesia, SW Poland). These plants, as used to evaluate the distribution of elements in the examined dumps, contained elevated levels of Cd, Co, Cu, Mn, Ni, Pb and Zn. Especially the highest levels of Mn in Betula pendula seriously exceed background values. Betula pendula characterized also the highest enrichment ratio for Mn, Salix caprea for Ni and Sr and Tanacetum vulgare for Cu. Test-t indicated that from both herbs Tanace-tum vulgare accumulated much more K, N, S and Zn than Solidago canadensis and of both trees Salix caprea accumulated significantly more Cd, Cu, K and Ca than Betula pendula, while this last species accumulated significantly more Fe and Mn than Salix caprea. A post hoc LSD test indicated that all examined plants had similar enrichment ratios for Al, Pb and V.

Influence of ZnO seed layer precursor molar ratio on the density of interface defects in low temperature aqueous chemically synthesized ZnO nanorods/GaN light-emitting diodes

Energy Technology Data Exchange (ETDEWEB)

Alnoor, Hatim, E-mail: hatim.alnoor@liu.se; Iandolo, Donata; Willander, Magnus; Nur, Omer [Department of Science and Technology (ITN), Linköping University, SE-601 74 Norrköping (Sweden); Pozina, Galia; Khranovskyy, Volodymyr; Liu, Xianjie [Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-583 81 Linköping (Sweden)

2016-04-28

Low temperature aqueous chemical synthesis (LT-ACS) of zinc oxide (ZnO) nanorods (NRs) has been attracting considerable research interest due to its great potential in the development of light-emitting diodes (LEDs). The influence of the molar ratio of the zinc acetate (ZnAc): KOH as a ZnO seed layer precursor on the density of interface defects and hence the presence of non-radiative recombination centers in LT-ACS of ZnO NRs/GaN LEDs has been systematically investigated. The material quality of the as-prepared seed layer as quantitatively deduced by the X-ray photoelectron spectroscopy is found to be influenced by the molar ratio. It is revealed by spatially resolved cathodoluminescence that the seed layer molar ratio plays a significant role in the formation and the density of defects at the n-ZnO NRs/p-GaN heterostructure interface. Consequently, LED devices processed using ZnO NRs synthesized with molar ratio of 1:5 M exhibit stronger yellow emission (∼575 nm) compared to those based on 1:1 and 1:3 M ratios as measured by the electroluminescence. Furthermore, seed layer molar ratio shows a quantitative dependence of the non-radiative defect densities as deduced from light-output current characteristics analysis. These results have implications on the development of high-efficiency ZnO-based LEDs and may also be helpful in understanding the effects of the ZnO seed layer on defect-related non-radiative recombination.

The effect of Cu/Zn molar ratio on CO{sub 2} hydrogenation over Cu/ZnO/ZrO{sub 2}/Al{sub 2}O{sub 3} catalyst

Energy Technology Data Exchange (ETDEWEB)

Shaharun, Salina, E-mail: salinashaharun@gmail.com, E-mail: maizats@petronas.com.my; Shaharun, Maizatul S., E-mail: salinashaharun@gmail.com, E-mail: maizats@petronas.com.my; Taha, Mohd F., E-mail: faisalt@petronas.com.my [Department of Fundamental and Applied Science, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia); Mohamad, Dasmawati, E-mail: dasmawati@kck.usm.my [School of Dental Sciences, Health Campus, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan (Malaysia)

2014-10-24

Catalytic hydrogenation of carbon dioxide (CO{sub 2}) to methanol is an attractive way to recycle and utilize CO{sub 2}. A series of Cu/ZnO/Al{sub 2}O{sub 3}/ZrO{sub 2} catalysts (CZAZ) containing different molar ratios of Cu/Zn were prepared by the co-precipitation method and investigated in a stirred slurry autoclave system. The catalysts were characterized by temperature-programmed reduction (TPR), field emission scanning electron microscopy-energy dispersive analysis (FESEM-EDX), X-ray diffraction (XRD) and N{sub 2} adsorption-desorption. Higher surface area, SA{sub BET} values (42.6–59.9 m{sup 2}/g) are recorded at low (1) and high (5) Cu/Zn ratios with the minimum value of 35.71 m{sup 2}/g found for a Cu/Zn of 3. The reducibility of the metal oxides formed after calcination of catalyst samples was also affected due to change in metal-support interaction. At a low reaction temperature of 443 K, total gas pressure of 3.0 MPa and 0.1 g/mL of the CZAZ catalyst, the selectivity to methanol decreased as the Cu/Zn molar ratio increased, and the maximum selectivity of 67.73 was achieved at Cu/Zn molar ratio of 1. With a reaction time of 3h, the best performing catalyst was CZAZ75 with Cu/Zn molar ratio of 5 giving methanol yield of 79.30%.

Growth of high-aspect ratio horizontally-aligned ZnO nanowire arrays.

Science.gov (United States)

Soman, Pranav; Darnell, Max; Feldman, Marc D; Chen, Shaochen

2011-08-01

A method of fabricating horizontally-aligned zinc-oxide (ZnO) nanowire (NW) arrays with full control over the width and length is demonstrated. SEM images reveal the hexagonal structure typical of zinc oxide NWs. Arrays of high-aspect ratio horizontal ZnO NWs are fabricated by making use of the lateral overgrowth from dot patterns created by electron beam lithography (EBL). An array of patterned wires are lifted off and transferred to a flexible PDMS substrate with possible applications in several key nanotechnology areas.

Quantitative microanalysis of Mn, Zn and other elements in mature wheat seed

International Nuclear Information System (INIS)

Mazzolini, A.P.; Pallaghy, C.K.; Legge, G.J.F.

1984-01-01

A scanning proton microprobe has been used to determine quantitatively the distribution of Mn,Zn and other elements in the mature wheat seed. Both X-ray and nuclear scattered proton data were collected during the irradiation of a 40 μ-thick longitudinal section, and these were used to calculate absolute elemental concentrations for the various features of interest in the embryo region. In the embryo, Mn was highest in the radicle (1400 +- 200 ppm) and lowest in the coleorhiza (200 +- 30 ppm), whereas Zn was highest in the scutellum (600 +- 100 ppm) and lowest in the leaf primordium (410 +- 70 ppm). Comparisons with direct bulk chemical analysis of excised embryos showed agreement. The possible biological significance of the distribution of elements is discussed

Fungal Transformation of Tree Stumps into a Suitable Resource for Xylophagous Beetles via Changes in Elemental Ratios

Directory of Open Access Journals (Sweden)

Michał Filipiak

2016-04-01

Full Text Available The elements present in dead pine stumps inhabited by larvae of wood-boring beetles (Stictoleptura rubra, Arhopalus rusticus and Chalcophora mariana were analyzed over the initial (first 5 years; a chronosequence stages of wood decay. The quantities of N, P, K, Ca, Mg, Fe, Zn, Mn, Cu and Na (but not S increased with increases in the content of ergosterol (used as a proxy for the amount of fungal tissue. In fact, the amounts of P, N, K, Fe and Cu presented marked increases. These findings show that fungi stoichiometrically rearrange dead wood by importing externally occurring nutrients to decaying stumps. During the first years of wood decay, the ratios of C to other elements decrease substantially, but differently, for various elements, whereas the N:Fe, N:Cu, N:P and N:K ratios remain relatively stable. Therefore, the stoichiometric mismatch between xylophages and their food is greatly reduced. By changing the nutritional stoichiometry of dead wood, fungi create a nutritional niche for wood-eaters, and these changes enable the development of xylophages.

Fungal Transformation of Tree Stumps into a Suitable Resource for Xylophagous Beetles via Changes in Elemental Ratios

Science.gov (United States)

Filipiak, Michał; Sobczyk, Łukasz; Weiner, January

2016-01-01

The elements present in dead pine stumps inhabited by larvae of wood-boring beetles (Stictoleptura rubra, Arhopalus rusticus and Chalcophora mariana) were analyzed over the initial (first 5 years; a chronosequence) stages of wood decay. The quantities of N, P, K, Ca, Mg, Fe, Zn, Mn, Cu and Na (but not S) increased with increases in the content of ergosterol (used as a proxy for the amount of fungal tissue). In fact, the amounts of P, N, K, Fe and Cu presented marked increases. These findings show that fungi stoichiometrically rearrange dead wood by importing externally occurring nutrients to decaying stumps. During the first years of wood decay, the ratios of C to other elements decrease substantially, but differently, for various elements, whereas the N:Fe, N:Cu, N:P and N:K ratios remain relatively stable. Therefore, the stoichiometric mismatch between xylophages and their food is greatly reduced. By changing the nutritional stoichiometry of dead wood, fungi create a nutritional niche for wood-eaters, and these changes enable the development of xylophages.

Effect of Zn/Sn molar ratio on the microstructural and optical properties of Cu2Zn1-xSnxS4 thin films prepared by spray pyrolysis technique

Science.gov (United States)

Thiruvenkadam, S.; Prabhakaran, S.; Sujay Chakravarty; Ganesan, V.; Vasant Sathe; Santhosh Kumar, M. C.; Leo Rajesh, A.

2018-03-01

Quaternary kesterite Cu2ZnSnS4 (CZTS) compound is one of the most promising semiconductor materials consisting of abundant and eco-friendly elements for absorption layer in thin film solar cells. The effect of Zn/Sn ratio on Cu2Zn1-xSnxS4 (0 ≤ x ≤ 1) thin films were studied by deposited by varying molar volumes in the precursor solution of zinc and tin was carried out in proportion of (1-x) and x respectively onto soda lime glass substrates kept at 573 K by using chemical spray pyrolysis technique. The GIXRD pattern revealed that the films having composites of Cu2ZnSnS4, Cu2SnS3, Sn2S3, CuS and ZnS phases. The crystallinity and grain size were found to increase by increasing the x value and the preferential orientation along (103), (112), (108) and (111) direction corresponding to CZTS, Cu2SnS3, CuS, and ZnS phases respectively. Micro-Raman spectra exposed a prominent peak at 332 cm-1 corresponding to the CZTS phase. Atomic force microscopy was employed to study the grain size and roughness of the deposited thin films. The optical band gap was found to lie between 1.45 and 2.25 eV and average optical absorption coefficient was found to be greater than 105 cm-1. Hall measurements exhibited that all the deposited Cu2Zn1-xSnxS4 films were p type and the resistivity lies between 10.9 ×10-2Ωcm and 149.6 × 10-2Ωcm .

Vertically integrated ZnO-Based 1D1R structure for resistive switching

International Nuclear Information System (INIS)

Zhang Yang; Duan Ziqing; Li Rui; Ku, Chieh-Jen; Reyes, Pavel I; Ashrafi, Almamun; Zhong Jian; Lu Yicheng

2013-01-01

We report a ZnO-based 1D1R structure, which is formed by a vertical integration of a FeZnO/MgO switching resistor (1R) and an Ag/MgZnO Schottky diode (1D). The multifunctional ZnO and its compounds are grown through MOCVD with in situ doping. For the R element, the current ratio of the high-resistance state (HRS) over the low-resistance state (LRS) at 1 V is 2.4 × 10 6 . The conduction mechanisms of the HRS and LRS are Poole–Frenkel emission and resistive conduction, respectively. The D element shows the forward/reverse current ratio at ±1 V to be 2.4 × 10 7 . This 1D1R structure exhibits high R HRS /R LRS ratio, excellent rectifying characteristics and robust retention. (paper)

Comparison of trace element contamination levels (Cu, Zn, Fe, Cd ...

African Journals Online (AJOL)

Comparison of trace element contamination levels (Cu, Zn, Fe, Cd and Pb) in the soft tissues of the gastropods Tympanotonus fuscatus fuscatus and Tf radula collected in the Ebrié Lagoon (Côte d'Ivoire): Evidence of the risks linked to linked to lead and.

Effect of starting pH and stabilizer/metal ion ratio on the photocatalytic activity of ZnS nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Devi, L. Meerabai; Negi, Devendra P.S., E-mail: dpsnegi@nehu.ac.in

2013-09-16

ZnS nanoparticles have been synthesized using the amino acid histidine as a stabilizing agent. The syntheses were carried out by varying the starting pH and histidine/Zn{sup 2+} ratio. The as-prepared ZnS nanoparticles were characterized by various analytical techniques. The photocatalytic activity of the ZnS nanoparticles was determined by studying the degradation of methyl orange. The ZnS nanoparticles synthesized with 1:1 histidine/Zn{sup 2+} ratio and starting pH of 10.3 were found to exhibit the highest photocatalytic activity. Nearly 95% of methyl orange was degraded in 30 min of irradiation using the photocatalyst. Particle size was not the main factor in determining the photocatalytic activity of the ZnS nanoparticles. Fluorescence lifetime measurements indicated that photocatalytic activity of the ZnS nanoparticles was enhanced with increase in their fluorescence lifetime. - Graphical abstract: Display Omitted - Highlights: • Photocatalytic activity of ZnS nanoparticles dependent on synthesis parameters. • About 95% of methyl orange degraded in 30 min of irradiation using optimal ZnS nanoparticles. • Particle size is not the main factor in determining the photocatalytic activity of ZnS. • Photocatalytic activity of ZnS was enhanced with increase in fluorescence lifetime.

Influence of Li/Nb ratios on defect structure and photorefractive properties of Zn: In: Fe: LiNbO 3 crystals

Science.gov (United States)

Dai, Li; Su, Yan-Qing; Wu, Shi-Ping; Guo, Jing-Jie; Xu, Chao; Xu, Yu-Heng

2011-04-01

A series of Zn: In: Fe: LiNbO3 crystals are grown by the Czochralski technique with various ratios of Li/Nb = 0.94, 1.05, 1.20 and 1.38 in the melt. The Zn, In, Fe, Nb and Li concentrations in the crystals are analyzed by inductively coupled plasma (ICP) spectrometry. The results indicate that with increasing the [Li]/[Nb] ratio in melt, [Li]/[Nb] ratio increases and goes up continuously in the crystal, the segregation coefficients of both Zn and In ions decrease. The absorption spectra measurement and two-wave coupling experiment are employed to study the effect of [Li]/[Nb] ratio on photorefractive properties of Zn: In: Fe: LiNbO3 crystals. It is found that the [Li]/[Nb] ratio increases, the write time is shortened and the photorefractive sensitivity is improved.

Effect of metal cation ratio on chemical properties of ZnFe2O4/AC composite and adsorption of organic contaminant

Science.gov (United States)

Meilia, Demara; Misbah Khunur, Mochamad; Setianingsih, Tutik

2018-01-01

Porous woody char is biochar prepared through pyrolisis. The biochar can be used as adsorbent. In this research, ZnFe2O4/AC composite was synthesized through imregnation of the woody biochar with ZnFe2O4 to study effect of mol ratio of Fe(III) and Zn(II) toward their physicochemistry and adsorption of drug wastewater. Paracetamol was used as adsorbate model. This research was conducted in several steps, including activation of the woody biochar using KOH activator at temperatur 500 °C for 15 min to produce the activated carbon, fungsionalization of the carbon using H2SO4 oxidator (6M) at temperature of 80 °C for 3 h, impregnation of the oxidized activated carbon with Zn-Fe-LDH (Layered Double Hydroxide) at various mol ratio of Fe(III) and Zn(III), including 1:2, 1:3 and 1:4 using NaOH solution (5M) for coprecipitation, and calcination of Zn-Fe-LDH/AC at 950 °C for 5 min to produce ZnFe2O4/AC. FTIR diffraction characterization indicated existence of M-O (M = Zn(II), Fe(III)) and OH functional groups. FTIR spectra showed increasing of bands connected to -OH by increasing of the ratio till the ratio was achieved at 1:4, then decreased again. The ratio mol showed effect on the adsorption of paracetamol. Profile of adsorption value was fit with changing of functional groups. The highest adsorption was achieved at the ratio of 1:4. After calcination it gave the adsorption value of 17,66 mg/g.

Geochemistry of CI chondrites: Major and trace elements, and Cu and Zn Isotopes

Science.gov (United States)

Barrat, J. A.; Zanda, B.; Moynier, F.; Bollinger, C.; Liorzou, C.; Bayon, G.

2012-04-01

In order to check the heterogeneity of the CI chondrites and determine the average composition of this group of meteorites, we analyzed a series of six large chips (weighing between 0.6 and 1.2 g) of Orgueil prepared from five different stones. In addition, one sample from each of Ivuna and Alais was analyzed. Although the sizes of the chips used in this study were “large”, our results show evidence for minor chemical heterogeneity in Orgueil, particularly for alkali elements and U. After removal of one outlier sample, the spread of the results is considerably reduced. For most of the 46 elements analyzed in this study, the average composition calculated for Orgueil is in very good agreement with previous CI estimates. This average, obtained with a “large” mass of samples, is analytically homogeneous and is suitable for normalization purposes. Finally, the Cu and Zn isotopic ratios are homogeneously distributed within the CI parent body with a spread of less than 100 ppm per atomic mass unit (amu).

Implications of Zn/Fe ratios for the sources of Colorado Plateau basalts

Science.gov (United States)

Rudzitis, S.; Reid, M. R.

2011-12-01

Early Miocene to recent mafic magmatism migrated across the Arizona Transition Zone towards the center of the stable Colorado Plateau at a rate of ~ 3-6 km/Myr (Roy et al., 2009). Present-day volcanic centers are close to a stepwise change in the thickness of the lithosphere between the Colorado Plateau and Basin and Range. Accordingly, volcanic migration might track progressive thinning of the lithosphere towards the center of the Colorado Plateau. This project aims to determine the conditions of melt generation across the transition zone in order to investigate the temporal/spatial correlation between volcanism and thinning of the Colorado Plateau lithosphere. Pressure and temperature estimates for Colorado Plateau basalts can be obtained from the Mg and Si contents of melts (Lee et al, 2009) but require melting of a peridotitic source. Eclogite and pyroxenite xenoliths reported in Colorado Plateau basalts show that melt sources could be olivine-poor. Zn/Fe ratios in melts can help to distinguish contributions from olivine-poor sources because they are sensitive to differences in bulk chemistry and to mineralogy (Le Roux et al., 2010). Specifically, Zn/Fe is not fractionated between melt, olivine, and orthopyroxene, but is highly fractionated when clinopyroxene and garnet are present. Our work to date has focused on laser ablation-IC-PMS analysis of individual olivine grains from high-Mg basalts (>8.0 wt. %) from the San Francisco and Mormon Mountain volcanic fields. Preliminary values of Zn/Fe ratios that represent the averages of multiple analyses of several grains in individual samples range from 7.9 to 9.3 (x10000). Variations of up to 1.7 (x10000) in the ratios exist between individual grains within samples and could be the result of co-crystallization of clinopyroxene with olivine. The lowest values in each sample should approach the Zn/Fe ratios of parental melts, and are, in turn, similar to MORB values and predicted peridotite melts. The results suggest

Measurement of total Zn and Zn isotope ratios by quadrupole ICP-MS for evaluation of Zn uptake in gills of brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss)

Science.gov (United States)

Wolf, R.E.; Todd, A.S.; Brinkman, S.; Lamothe, P.J.; Smith, K.S.; Ranville, J.F.

2009-01-01

This study evaluates the potential use of stable zinc isotopes in toxicity studies measuring zinc uptake by the gills of brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss). The use of stable isotopes in such studies has several advantages over the use of radioisotopes, including cost, ease of handling, elimination of permit requirements, and waste disposal. A pilot study using brown trout was performed to evaluate sample preparation methods and the ability of a quadrupole inductively coupled plasma mass spectrometer (ICP-MS) system to successfully measure changes in the 67Zn/66Zn ratios for planned exposure levels and duration. After completion of the pilot study, a full-scale zinc exposure study using rainbow trout was performed. The results of these studies indicate that there are several factors that affect the precision of the measured 67Zn/66Zn ratios in the sample digests, including variations in sample size, endogenous zinc levels, and zinc uptake rates by individual fish. However, since these factors were incorporated in the calculation of the total zinc accumulated by the gills during the exposures, the data obtained were adequate for their intended use in calculating zinc binding and evaluating the influences of differences in water quality parameters.

Effect of vanadium treatment on tissue distribution of biotrace elements in normal and streptozotocin-induced diabetic rats. Simultaneous analysis of V and Zn using radioactive multitracer

International Nuclear Information System (INIS)

Yasui, Hiroyuki; Takino, Toshikazu; Fugono, Jun; Sakurai, Hiromu; Hirunuma, Rieko; Enomoto, Shuichi

2001-01-01

Because vanadium ions such as vanadyl (VO 2+ ) and vanadate (VO 3- ) ions were demonstrated to normalize blood glucose levels of diabetic animals and patients, the action mechanism of vanadium treatment has been of interest. In this study, we focused on understanding interactions among trace elements in diabetic rats, in which a multitracer technique was used. The effects of vanadyl sulfate (VS)-treatment on the tissue distribution of trace vanadium ( 48 V) and zinc ( 65 Zn) in normal and streptozotocin (STZ)-induced diabetic rats were examined, and were evaluated in terms of the uptake ratio. The uptake ratio of both elements in tissues significantly changed between STZ-rats and those treated with VS. These results indicated that vanadium treatment in STZ-rats alters the tissue distribution of endogenous elements, suggesting the importance of the relationship between biotrace elements and pathophysiology. (author)

Preparation and characterization of ZnTe thin films by SILAR method

International Nuclear Information System (INIS)

Kale, S.S.; Mane, R.S.; Pathan, H.M.; Shaikh, A.V.; Joo, Oh-Shim; Han, Sung-Hwan

2007-01-01

Nanocrystalline zinc telluride (ZnTe) thin films were prepared by using successive ionic layer adsorption and reaction (SILAR) method from aqueous solutions of zinc sulfate and sodium telluride. The films were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis and optical absorption measurement techniques. The synthesized ZnTe thin films were nanocrystalline with densely aggregated particles in nanometer scale and were free from the voids or cracks. The optical band gap energy of the film was found to be thickness dependent. The elemental chemical compositional stoichiometric analysis revealed good Zn:Te elemental ratio of 53:47

A Resistive Humidity Sensor Based on Nanostructured WO3-ZnO Composites

Directory of Open Access Journals (Sweden)

Karunesh Tiwari

2011-11-01

Full Text Available Paper reports morphological and humidity sensing studies of WO3 and WO3-ZnO composite pellets prepared in the weight % ratio of 10:1, 4:1 and 2:1 by solid-state reaction route. The pellets have been annealed at temperatures of 300-500 °C. XRD pattern shows peaks of ZnWO4 formed due to solid state reaction between WO3 and ZnO. SEM micrographs show that the sensing elements manifest porous structure. Granulation and tendency to agglomerate seen in the SEM micrograph are due to the presence of zinc ions in ZnWO4. Nanoparticles are having their sizes in the range 37-182 nm. The average Kelvin radius at 20˚C room temperature is 27 Ả. Humidity sensing application of the pellets has been studied in a humidity control cabinet. It is observed that as relative humidity increases, there is decrease in the resistance of pellets in the range 10-85 % RH. Sensing element of WO3-ZnO in 2:1 weight % ratio shows best results in 10-85 % relative humidity range. The average sensitivity of this sample is 1.25 MΩ/%RH. This sensing element shows good reproducibility, low hysteresis and less effect of aging.

Elimination of Cu (II) and Zn (II) ions in mono-element and the bi ...

African Journals Online (AJOL)

Elimination of Cu (II) and Zn (II) ions in mono-element and the bi-element aqueous solutions by adsorption on natural clay of Bikougou (Gabon) ... The modeling of the experimental results is better achieved by application of. Freundlich adsorption isotherm and Langmuir adsorption isotherm concerning the adsorption of Cu ...

Impact of Zn, Mg, Ni and Co elements on glass alteration: Additive effects

Energy Technology Data Exchange (ETDEWEB)

Aréna, H., E-mail: helene.arena@cea.fr [CEA, DEN, DTCD, LCLT, Centre de Marcoule, F-30207 Bagnols sur Cèze Cedex (France); Godon, N. [CEA, DEN, DTCD, LCLT, Centre de Marcoule, F-30207 Bagnols sur Cèze Cedex (France); Rébiscoul, D.; Podor, R. [ICSM-UMR5257 CNRS/CEA/UM2/ENCSM, Site de Marcoule, Bat. 426, 30207 Bagnols/Cèze (France); Garcès, E. [CEA, DEN, DTCD, LCLT, Centre de Marcoule, F-30207 Bagnols sur Cèze Cedex (France); Cabie, M. [Aix-Marseille Université, CP2M, F-13397 Marseille (France); Mestre, J.-P. [CEA, DEN, DTCD, LCLT, Centre de Marcoule, F-30207 Bagnols sur Cèze Cedex (France)

2016-03-15

The minor elements present in the nuclear glass composition or coming from the groundwater of the future repository may impact glass alteration. In this study, the effects of Zn, Mg, Ni and Co on the International Simple Glass (ISG) alteration were studied throughout 511 days of aqueous leaching experiments. The aim was to determine their additive or competitive effect on glass alteration and the nature of the alteration products. The four elements were introduced separately or altogether in solution as XCl{sub 2} chloride salts (X = Zn, Mg, Ni or Co) with monthly additions to compensate for their consumption. The alteration kinetics were determined by leachate analyses (ICP-AES) and alteration products were characterized in terms of composition, morphology and microstructure (SEM, TEM-EDX, ToF-SIMS and XRD). Results indicate that when they are introduced separately, Zn, Mg, Ni and Co have the same qualitative and quantitative effect on glass alteration kinetics and on pH: they form secondary phases leading to a pH decrease and a significant increase in glass alteration. The secondary phases were identified as silicates of the added X element: trioctahedral smectites with a stoichiometry of[(Si{sub (4-a)} Al{sub a}) (X{sub (3-b)} Al{sub b}) O{sub 10} (OH){sub 2}]{sup (a+b)−} [X{sub c} Na{sub d} Ca{sub e}] {sup (2c+d+2e) +} with a = 0.11 to 0.45, b = 0.00 to 0.29, c = 0, d = 0.19 to 0.74 and e = 0.10 to 0.14. . It was shown that as pH stabilizes at a minimum value, X-silicates no longer precipitate, thus leading to a significant drop in the glass alteration rate. This pH value depends on X and it has been identified as being 8 for Mg-silicates, probably around 7.3 for Ni and Co-silicates and less than 6.2 for Zn-silicates. When tested together, the effects of these four elements on glass alteration are additive and lead to the formation of a mix of X-silicates that precipitate as long as their constitutive elements are available and the pH is above

A history of violence: Insights into post-accretionary heating in carbonaceous chondrites from volatile element abundances, Zn isotopes and water contents

Science.gov (United States)

Mahan, Brandon; Moynier, Frédéric; Beck, Pierre; Pringle, Emily A.; Siebert, Julien

2018-01-01

Carbonaceous chondrites (CCs) may have been the carriers of water, volatile and moderately volatile elements to Earth. Investigating the abundances of these elements, their relative volatility, and isotopes of state-change tracer elements such as Zn, and linking these observations to water contents, provide vital information on the processes that govern the abundances and isotopic signatures of these species in CCs and other planetary bodies. Here we report Zn isotopic data for 28 CCs (20 CM, 6 CR, 1 C2-ung, and 1 CV3), as well as trace element data for Zn, In, Sn, Tl, Pb, and Bi in 16 samples (8 CM, 6 CR, 1 C2-ung, and 1 CV3), that display a range of elemental abundances from case-normative to intensely depleted. We use these data, water content data from literature and Zn isotopes to investigate volatile depletions and to discern between closed and open system heating. Trace element data have been used to construct relative volatility scales among the elements for the CM and CR chondrites. From least volatile to most, the scale in CM chondrites is Pb-Sn-Bi-In-Zn-Tl, and for CR chondrites it is Tl-Zn-Sn-Pb-Bi-In. These observations suggest that heated CM and CR chondrites underwent volatile loss under different conditions to one another and to that of the solar nebula, e.g. differing oxygen fugacities. Furthermore, the most water and volatile depleted samples are highly enriched in the heavy isotopes of Zn. Taken together, these lines of evidence strongly indicate that heated CM and CR chondrites incurred open system heating, stripping them of water and volatiles concomitantly, during post-accretionary shock impact(s).

Effects of the aspect ratio on the dye adsorption of ZnO nanorods grown by using a sonochemical method for dye-sensitized solar cells

International Nuclear Information System (INIS)

Choi, Seok Cheol; Yun, Won Suk; Sohn, Sang Ho; Oh, Sang Jin

2012-01-01

Well-aligned ZnO nanorods for the photoelectrode of dye-sensitized solar cells (DSSCs) were grown via a sonochemical method, and the effects of their aspect ratios on the dye adsorption in DSSCs were studied. The control of the aspect ratio of well-aligned ZnO nanorods was performed by tuning the mole concentration of zinc acetate dehydrate in the range of 0.04 ∼ 0.06M. The dye amounts adsorbed in the ZnO nanorods were estimated from the UV-Visible absorbance by using the Beer-Lambert law. The efficiency of DSSCs with ZnO nanorods was measured to investigate the effects of the aspect ratio of the ZnO nanorods on the dye adsorption properties. A change in the aspect ratio of the ZnO nanorods was founded to yield a change in their dye adsorption ability, resulting in a change in the efficiency of the DSSCs.

Buckling of ZnS-filled single-walled carbon nanotubes – The influence of aspect ratio

KAUST Repository

Monteiro, André O.

2014-08-16

The mechanical response of single-walled carbon nanotubes (SWCNT) filled with crystalline zinc sulphide (ZnS) nanowires under uniaxial compression is studied using classical molecular dynamics. These simulations were used to analyse the behaviour of SWCNT, with and without ZnS filling, in terms of critical force and critical strain. Force versus strain curves have been computed for hollow and filled systems, the latter clearly showing an improvement of the mechanical behaviour caused by the ZnS nanowire. The same simulations were repeated for a large range of dimensions in order to evaluate the influence of the aspect ratio on the mechanical response of the tubes.

Effect of vanadium treatment on tissue distribution of biotrace elements in normal and streptozotocin-induced diabetic rats. Simultaneous analysis of V and Zn using radioactive multitracer

Energy Technology Data Exchange (ETDEWEB)

Yasui, Hiroyuki; Takino, Toshikazu; Fugono, Jun; Sakurai, Hiromu [Department of Analytical and Bioinorganic Chemistry, Kyoto Pharmaceutical University, Kyoto (Japan); Hirunuma, Rieko; Enomoto, Shuichi [Radioisotope Technology Division, Cyclotron Center, Institute of Physical and Chemical Research (RIKEN), Wako, Saitama (Japan)

2001-05-01

Because vanadium ions such as vanadyl (VO{sup 2+}) and vanadate (VO{sup 3-}) ions were demonstrated to normalize blood glucose levels of diabetic animals and patients, the action mechanism of vanadium treatment has been of interest. In this study, we focused on understanding interactions among trace elements in diabetic rats, in which a multitracer technique was used. The effects of vanadyl sulfate (VS)-treatment on the tissue distribution of trace vanadium ({sup 48}V) and zinc ({sup 65}Zn) in normal and streptozotocin (STZ)-induced diabetic rats were examined, and were evaluated in terms of the uptake ratio. The uptake ratio of both elements in tissues significantly changed between STZ-rats and those treated with VS. These results indicated that vanadium treatment in STZ-rats alters the tissue distribution of endogenous elements, suggesting the importance of the relationship between biotrace elements and pathophysiology. (author)

Methodology to obtain exchange properties of the calcite surface-Application to major and trace elements: Ca(II), HCO3-, and Zn(II)

International Nuclear Information System (INIS)

Tertre, E.; Beaucaire, C.; Juery, A.; Ly, J.; Tertre, E.; Beaucaire, C.; Juery, A.; Ly, J.

2010-01-01

Sorption of inorganic elements onto carbonate minerals has been intensively described in the literature by two reaction steps: (1) a first one rapid and completed within a few hours and (2) a second one slower, eventually irreversible, and occurring at a constant rate. The first step is often attributed to an ion-exchange process, but its reversibility is rarely investigated. Consequently, discrimination of the global sorption phenomenon into two different mechanisms is not always justified. In this study, we investigated, by batch experiments, both sorption and desorption of Ca(II), HCO 3 - , and Zn(II), radiolabeled with isotopes 45 Ca(II), H 14 CO 3 - , and 65 Zn(II), respectively, onto synthetic pure calcite. Solutions were pre-equilibrated with atmospheric p(CO 2 ) and saturated with respect to calcite. Therefore, our purpose was to: (1) obtain experimental distribution coefficients of major elements (Ca(II) and HCO 3 - ) and a trace element (Zn(II)) onto calcite from sorption and desorption experiments, (2) test the validity of a first-occurring ion-exchange process generally noted in the literature, by calculating distribution coefficients for the 'sole' exchange process, and (3) quantify the amounts of Ca(II), HCO 3 - , and Zn(II) sorbed on the calcite surface by the sole 'exchange process' and compare them with surface crystallochemical data. Ca(II) or HCO 3 - sorption experimental data suggest that a significant fraction of these two elements was sorbed irreversibly onto or in the calcite. By using a method based on isotopic ratios, the Ca(II) or HCO 3 - concentrations, which are reversibly adsorbed on the calcite, have been quantified. These concentrations are respectively estimated at 4. 0 ± 2. 0 * 10 -4 and 7. 0 ± 1. 5 * 10 -4 mol/kg. The obtained Ca(II) surface concentration value is one order of magnitude lower than the one obtained from isotopic measurement by former authors [Geochim. Cosmochim. Acta 55 (1991) 1549; Geochim. Cosmochim. Acta 51

Effect of methanol ratio in mixed solvents on optical properties and wettability of ZnO films by cathodic electrodeposition

International Nuclear Information System (INIS)

Zhang, Miao; Xu, Kai; Jiang, Xishun; Yang, Lei; He, Gang; Song, Xueping; Sun, Zhaoqi; Lv, Jianguo

2014-01-01

Highlights: • Different surface morphologies of ZnO films were prepared by cathodic electrodeposition. • The surface morphologies are controlled through add different ratio methanol to electrolyte. • The morphology changes from nanorods with hexagonal structure to net-like nanostructure. • The wettability of films shows obvious change with increasing methanol ratio. • The maximum light-induced CA change has been observed with the methanol ratio of 0.8. - Abstract: ZnO thin films were prepared in the electrolyte with different methanol ratio by cathodic electrodeposition method. Microstructure, surface morphology, optical properties and wettability of the thin films were investigated by X-ray diffractometer, field-emission scanning electron microscope, ultraviolet–visible spectroscope, fluorescence spectrometer and water contact angle apparatus. Increase of methanol ratio in the solvents may restrain the (0 0 2) plane preferential orientation in some extent. Change of current density curves with the ratio of methanol in the solution play a vital role on electrochemical reaction kinetics, microstructure and/or surface morphology of ZnO thin films. With the methanol ratio increase from 0 to 0.8, the surface morphology changes from nanorods to net-like nanostructure. The adsorbed NO 3 − ions on the polar planes hinder the crystal growth along the c-axis and redirect the growth direction along the nonpolar planes. The maximum and minimum band gaps have been obtained in the ZnO thin films with the methanol ratio of 0.4 and 0.6, respectively. Change of contact angle before UV irradiation may be related to surface morphology and oxygen vacancies. The maximum light-induced water contact angle change has been observed in the sample with the methanol ratio of 0.8. The results may be attributed to the higher surface roughness and net-like morphology

Effect of methanol ratio in mixed solvents on optical properties and wettability of ZnO films by cathodic electrodeposition

Energy Technology Data Exchange (ETDEWEB)

Zhang, Miao; Xu, Kai; Jiang, Xishun; Yang, Lei; He, Gang; Song, Xueping [School of Physics and Material Science, Anhui University, Hefei 230601 (China); Sun, Zhaoqi, E-mail: szq@ahu.edu.cn [School of Physics and Material Science, Anhui University, Hefei 230601 (China); Lv, Jianguo, E-mail: lvjg1@163.com [School of Electronic and Information Engineering, Hefei Normal University, Hefei 230601 (China)

2014-12-05

Highlights: • Different surface morphologies of ZnO films were prepared by cathodic electrodeposition. • The surface morphologies are controlled through add different ratio methanol to electrolyte. • The morphology changes from nanorods with hexagonal structure to net-like nanostructure. • The wettability of films shows obvious change with increasing methanol ratio. • The maximum light-induced CA change has been observed with the methanol ratio of 0.8. - Abstract: ZnO thin films were prepared in the electrolyte with different methanol ratio by cathodic electrodeposition method. Microstructure, surface morphology, optical properties and wettability of the thin films were investigated by X-ray diffractometer, field-emission scanning electron microscope, ultraviolet–visible spectroscope, fluorescence spectrometer and water contact angle apparatus. Increase of methanol ratio in the solvents may restrain the (0 0 2) plane preferential orientation in some extent. Change of current density curves with the ratio of methanol in the solution play a vital role on electrochemical reaction kinetics, microstructure and/or surface morphology of ZnO thin films. With the methanol ratio increase from 0 to 0.8, the surface morphology changes from nanorods to net-like nanostructure. The adsorbed NO{sub 3}{sup −} ions on the polar planes hinder the crystal growth along the c-axis and redirect the growth direction along the nonpolar planes. The maximum and minimum band gaps have been obtained in the ZnO thin films with the methanol ratio of 0.4 and 0.6, respectively. Change of contact angle before UV irradiation may be related to surface morphology and oxygen vacancies. The maximum light-induced water contact angle change has been observed in the sample with the methanol ratio of 0.8. The results may be attributed to the higher surface roughness and net-like morphology.

Segregation of solute elements at grain boundaries in an ultrafine grained Al-Zn-Mg-Cu alloy

International Nuclear Information System (INIS)

Sha, Gang; Yao, Lan; Liao, Xiaozhou; Ringer, Simon P.; Chao Duan, Zhi; Langdon, Terence G.

2011-01-01

The solute segregation at grain boundaries (GBs) of an ultrafine grained (UFG) Al-Zn-Mg-Cu alloy processed by equal-channel angular pressing (ECAP) at 200 o C was characterised using three-dimensional atom probe. Mg and Cu segregate strongly to the grain boundaries. In contrast, Zn does not always show clear segregation and may even show depletion near the grain boundaries. Trace element Si selectively segregates at some GBs. An increase in the number of ECAP passes leads to a decrease in the grain size but an increase in solute segregation at the boundaries. The significant segregation of alloying elements at the boundaries of ultrafine-grained alloys implies that less solutes will be available in the matrix for precipitation with a decrease in the average grain size. -- Research Highlights: → Atom probe tomography has been employed successfully to reveal unique segregation of solutes at ultrafine grained material. → Mg and Cu elements segregated strongly at the grain boundary of an ultrafine grained Al-Zn-Mg-Cu alloy processed by 4-pass and 8-pass ECAP at 200 o C. Zn frequently depleted at GBs with a Zn depletion region of 7-15 nm in width on one or both sides of the GBs. Only a small fraction (3/13) of GBs were observed with a low level of Zn segregation where the combined Mg and Cu excess is over 3.1 atom/nm 2 . Si appeared selectively segregated at some of the GBs. → The increase in number of ECAP passes from 4 to 8 correlated with the increase in mean level segregation of Mg and Cu for both solute excess and peak concentration. → The change of plane normal of a grain boundary within 30 o only leads to a slight change in the solute segregation level.

Mechanisms involved in the hydrothermal growth of ultra-thin and high aspect ratio ZnO nanowires

Energy Technology Data Exchange (ETDEWEB)

Demes, Thomas [Univ. Grenoble Alpes, CNRS, Grenoble-INP, LMGP, F-38000 Grenoble (France); Ternon, Céline, E-mail: celine.ternon@grenoble-inp.fr [Univ. Grenoble Alpes, CNRS, Grenoble-INP, LMGP, F-38000 Grenoble (France); Univ. Grenoble Alpes, CNRS, LTM, F-38000 Grenoble (France); Morisot, Fanny [Univ. Grenoble Alpes, CNRS, Grenoble-INP, LMGP, F-38000 Grenoble (France); Univ. Grenoble Alpes, CNRS, Grenoble-INP" 2, IMEP-LaHC, F-38000 Grenoble (France); Riassetto, David [Univ. Grenoble Alpes, CNRS, Grenoble-INP, LMGP, F-38000 Grenoble (France); Legallais, Maxime [Univ. Grenoble Alpes, CNRS, Grenoble-INP, LMGP, F-38000 Grenoble (France); Univ. Grenoble Alpes, CNRS, Grenoble-INP" 2, IMEP-LaHC, F-38000 Grenoble (France); Roussel, Hervé; Langlet, Michel [Univ. Grenoble Alpes, CNRS, Grenoble-INP, LMGP, F-38000 Grenoble (France)

2017-07-15

Highlights: • ZnO nanowires are grown on sol-gel ZnO seed layers by hydrothermal synthesis. • Ultra-thin and high aspect ratio nanowires are obtained without using additives. • Nanowire diameter is 20–25 nm regardless of growth time and seed morphology. • A nanowire growth model is developed on the basis of thermodynamic considerations. • The nanowires are intended for integration into electrically conductive nanonets. - Abstract: Hydrothermal synthesis of ZnO nanowires (NWs) with tailored dimensions, notably high aspect ratios (AR) and small diameters, is a major concern for a wide range of applications and still represents a challenging and recurring issue. In this work, an additive-free and reproducible hydrothermal procedure has been developed to grow ultra-thin and high AR ZnO NWs on sol-gel deposited ZnO seed layers. Controlling the substrate temperature and using a low reagent concentration (1 mM) has been found to be essential for obtaining such NWs. We show that the NW diameter remains constant at about 20–25 nm with growth time contrary to the NW length that can be selectively increased leading to NWs with ARs up to 400. On the basis of investigated experimental conditions along with thermodynamic and kinetic considerations, a ZnO NW growth mechanism has been developed which involves the formation and growth of nuclei followed by NW growth when the nuclei reach a critical size of about 20–25 nm. The low reagent concentration inhibits NW lateral growth leading to ultra-thin and high AR NWs. These NWs have been assembled into electrically conductive ZnO nanowire networks, which opens attractive perspectives toward the development of highly sensitive low-cost gas- or bio-sensors.

Influence of Ca/Mg ratio on phytoextraction properties of Salix viminalis. II. Secretion of low molecular weight organic acids to the rhizosphere.

Science.gov (United States)

Magdziak, Z; Kozlowska, M; Kaczmarek, Z; Mleczek, M; Chadzinikolau, T; Drzewiecka, K; Golinski, P

2011-01-01

A hydroponic experiment in a phytotron was performed to investigate the effect of two different Ca/Mg ratios (4:1 and 1:10) and trace element ions (Cd, Cu, Pb and Zn) in solution on the efficiency of low molecular weight organic acid (LMWOA) formation in Salix viminalis rhizosphere. Depending on the Ca/Mg ratio and presence of selected trace elements at 0.5mM concentration, the amount and kind of LMWOAs in the rhizosphere were significantly affected. In physiological 4:1 Ca/Mg ratio the following complex of acids was observed: malonic (Pb, Zn), citric, lactic, maleic and succinic (Zn) acids. Under 1:10 Ca/Mg ratio, citric (Cd, Zn), maleic and succinic (Cd, Cu, Pb, Zn) acids were seen. Additionally, high accumulation of zinc and copper in all systems was observed, with the exception of those where one of the metals was at higher concentration. Summing up, the results indicate a significant role of LMWOAs in Salix phytoremediation abilities. Both effects can be modulated depending on the mutual Ca/Mg ratio. Copyright © 2010 Elsevier Inc. All rights reserved.

Synthesis and characterization of heterobinuclear (La-Zn, Pr-Zn, Nd-Zn, Sm-Zn, Eu-Zn, Gd-Zn, Tb-Zn, Dy-Zn) azine-bridged complexes

International Nuclear Information System (INIS)

Singh, Bachcha; Srivastav, A.K.; Singh, P.K.

1997-01-01

Zinc(II) complex of 2-acetylpyridine salicyl aldazine (Haps) of the type Zn(aps) 2 (H 2 O) 2 has been synthesised. The reaction of Zn(aps) 2 (H 2 O) 2 with lanthanide chlorides, LnCl 3 (where Ln=La, Pr, Nd, Sm, Eu, Gd, Tb and Dy) yields azine-bridged heterobinuclear complexes of the formulae LnCl 3 Zn(aps) 2 (H 2 O) 2 . These complexes have been characterized by elemental analyses, molecular weight, conductance (solid and solution) and magnetic susceptibility measurements, mass, IR and electronic spectral data. X-ray powder diffraction data indicate the tetragonal unit lattice for Zn(aps) 2 (H 2 O) 2 and PrCl 3 Zn(aps) 2 (H 2 O) 2 . (author)

Understanding corrosion behavior of Mg-Zn-Ca alloys from subcutaneous mouse model: effect of Zn element concentration and plasma electrolytic oxidation.

Science.gov (United States)

Jang, Yongseok; Tan, Zongqing; Jurey, Chris; Xu, Zhigang; Dong, Zhongyun; Collins, Boyce; Yun, Yeoheung; Sankar, Jagannathan

2015-03-01

Mg-Zn-Ca alloys are considered as suitable biodegradable metallic implants because of their biocompatibility and proper physical properties. In this study, we investigated the effect of Zn concentration of Mg-xZn-0.3Ca (x=1, 3 and 5wt.%) alloys and surface modification by plasma electrolytic oxidation (PEO) on corrosion behavior in in vivo environment in terms of microstructure, corrosion rate, types of corrosion, and corrosion product formation. Microstructure analysis of alloys and morphological characterization of corrosion products were conducted using x-ray computed tomography (micro-CT) and scanning electron microscopy (SEM). Elemental composition and crystal structure of corrosion products were determined using x-ray diffraction (XRD) and electron dispersive x-ray spectroscopy (EDX). The results show that 1) as-cast Mg-xZn-0.3Ca alloys are composed of Mg matrix and a secondary phase of Ca2Mg6Zn3 formed along grain boundaries, 2) the corrosion rate of Mg-xZn-0.3Ca alloys increases with increasing concentration of Zn in the alloy, 3) corrosion rates of alloys treated by PEO sample are decreased in in vivo environment, and 4) the corrosion products of these alloys after in vivo tests are identified as brucite (Mg(OH)2), hydroxyapatite (Ca10(PO4)6(OH)2), and magnesite (MgCO3·3H2O). Copyright © 2014 Elsevier B.V. All rights reserved.

Synthesis of high aspect ratio ZnO nanowires with an inexpensive handcrafted electrochemical setup

Energy Technology Data Exchange (ETDEWEB)

Taheri, Ali, E-mail: at1361@aut.ac.ir, E-mail: atahery@aeoi.org.ir [Nuclear Science and Technology Institute (Iran, Islamic Republic of); Saramad, Shahyar; Setayeshi, Saeed [Amirkabir University of Technology, Faculty of Energy Engineering and Physics (Iran, Islamic Republic of)

2016-12-15

In this work, high aspect ratio zinc oxide nanowires are synthesized using templated one-step electrodeposition technique. Electrodeposition of the nanowires is done using a handcrafted electronic system. Nuclear track-etched polycarbonate membrane is used as a template to form the high aspect ratio nanowires. The result of X-ray diffraction and scanning electron microscopy shows that nanowires with a good crystallinity and an aspect ratio of more than 30 can be achieved in a suitable condition. The height of electrodeposited nanowires reaches to about 11 μm. Based on the obtained results, high aspect ratio ZnO nanowires can be formed using inexpensive electrodeposition setup with an acceptable quality.

Сomposition and ratio of the chemical elements on the surfaces different by height of reindeer lichen podetia Cladonia rangiferina

Directory of Open Access Journals (Sweden)

Byazrov Lev

2016-06-01

Full Text Available In the paper the composition of 21 elements – Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Sr, Ba, Pb – was compared in the upper, central, and lower parts of podetia surfaces of the reindeer lichen Cladonia rangiferina, sampled on the slope of Barguzinsky chain. For the measurement of the elements content (%, a sample-nondestructive μ-XRF spectrometer was used. It was stated that the share (% of the most elements, except for Cu and Zn, was highly variable. The content of the elements on the surfaces differs significantly between the studied parts of C. rangiferina podetia: mean values of the content of P, S, Cl, and K were statistically higher on the surface of the upper part of podetia, while those of Al, Si, Ca, Ti, Cr, Mn, Fe, Cu, Zn, Co, and the total content – on the surface of the lower part of podetia. On all the parts of podetia very high value of the enrichment factor for As and Pb was established, and It was increased for P, Co, Ni, Cu, Zn.

Influence of S186 on trace elements in organs of dogs

International Nuclear Information System (INIS)

Luo Meichu; Li Landi; Chen Guibao; Zhang Meizhen

1993-01-01

The authors report the influence of a radiostrontium de-cooperating agents, S186 (calcium sodium N-acetylproplysmine 1, 1-diphosphonate), on trace elements in internal organs of dogs. The trace elements contents were determined with a PE-3030 atomic absorption spectrophotometer. Compared with the control group, the trace elements (Cu, Zn and Mn) contents and the Cu/Zn ratio in organs of Beagle dogs after intramuscular injection of S186 for 30 days did not change obviously except the Cu content in the liver increased

Development of textured ZnO-coated low-cost glass substrate with very high haze ratio for silicon-based thin film solar cells

Energy Technology Data Exchange (ETDEWEB)

Hongsingthong, Aswin, E-mail: aswin.hongsingthong@nectec.or.th [Solar Energy Technology Laboratory, National Electronics and Computer Technology Center, 112 Thailand Science Park, Phahonyothin Road, Khlong 1, Khlong Luang, Pathumthani 12120 (Thailand); Krajangsang, Taweewat; Limmanee, Amornrat; Sriprapha, Kobsak; Sritharathikhun, Jaran [Solar Energy Technology Laboratory, National Electronics and Computer Technology Center, 112 Thailand Science Park, Phahonyothin Road, Khlong 1, Khlong Luang, Pathumthani 12120 (Thailand); Konagai, Makoto [Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1, NE-15, O-okayama, Meguro-ku, Tokyo 152-8552 (Japan)

2013-06-30

Zinc oxide (ZnO) films with a very high haze ratio and low resistivity were developed on soda–lime glass substrate by using reactive ion etching (RIE) treatment with carbon tetrafluoride (CF{sub 4}) to modify the substrate surface morphology before the deposition of ZnO films. We found that the surface morphology of the ZnO films deposited by metal organic chemical vapor deposition (MOCVD) technique could be modified by varying the glass treatment conditions and the gas pressure was a key parameter. With increasing glass-etching pressure, the surface morphology of the ZnO films changed from conventional pyramid-like single texture to greater cauliflower-like double texture, leading to significant increases in root mean square roughness and haze ratio of the films. By employing the developed high-haze ZnO films as a front transparent conductive oxide (TCO) layer in microcrystalline silicon solar cells, an enhancement in the quantum efficiency in the long-wavelength region has been achieved. Experimental results have verified that our unique and original glass etching treatment is a simple and effective technique to improve the light-scattering properties of the ZnO films while preserving their good transparency and electrical properties. Thus, the ZnO films deposited on etched soda–lime glass have a high potential for the use as a front TCO layer in thin-film Si solar cells. - Highlights: • High-haze zinc oxide (ZnO) grown on low cost soda–lime glass has been developed. • Surface of the ZnO can be modified by varying glass-substrate etching conditions. • Glass-etching pressure is a key to increase haze ratio of the ZnO films. • Higher cell efficiency has been achieved from cell using etched glass. • High-haze ZnO coated glass is a promising transparent conductive oxide coated glass.

Development of textured ZnO-coated low-cost glass substrate with very high haze ratio for silicon-based thin film solar cells

International Nuclear Information System (INIS)

Hongsingthong, Aswin; Krajangsang, Taweewat; Limmanee, Amornrat; Sriprapha, Kobsak; Sritharathikhun, Jaran; Konagai, Makoto

2013-01-01

Zinc oxide (ZnO) films with a very high haze ratio and low resistivity were developed on soda–lime glass substrate by using reactive ion etching (RIE) treatment with carbon tetrafluoride (CF 4 ) to modify the substrate surface morphology before the deposition of ZnO films. We found that the surface morphology of the ZnO films deposited by metal organic chemical vapor deposition (MOCVD) technique could be modified by varying the glass treatment conditions and the gas pressure was a key parameter. With increasing glass-etching pressure, the surface morphology of the ZnO films changed from conventional pyramid-like single texture to greater cauliflower-like double texture, leading to significant increases in root mean square roughness and haze ratio of the films. By employing the developed high-haze ZnO films as a front transparent conductive oxide (TCO) layer in microcrystalline silicon solar cells, an enhancement in the quantum efficiency in the long-wavelength region has been achieved. Experimental results have verified that our unique and original glass etching treatment is a simple and effective technique to improve the light-scattering properties of the ZnO films while preserving their good transparency and electrical properties. Thus, the ZnO films deposited on etched soda–lime glass have a high potential for the use as a front TCO layer in thin-film Si solar cells. - Highlights: • High-haze zinc oxide (ZnO) grown on low cost soda–lime glass has been developed. • Surface of the ZnO can be modified by varying glass-substrate etching conditions. • Glass-etching pressure is a key to increase haze ratio of the ZnO films. • Higher cell efficiency has been achieved from cell using etched glass. • High-haze ZnO coated glass is a promising transparent conductive oxide coated glass

Copperton - Areachap Cu-Zn mineralization

International Nuclear Information System (INIS)

Theart, H.F.J.

1985-05-01

Stratiform massive sulfide deposit at the Prieska Cu-Zn and Areachap mines are situated close to the eastern margin of the Namaqua Province, South Africa, within the Copperton and Jannelsepan Formations. The investigation of the petrology and geochemistry of the Prieska Cu-Zn deposits forms the basis of this study. Borehole core and surface samples were investigated petrographically. Knowledge gained during this investigation was used to select suitable samples for geochemical analysis. Suites of samples were analysed for their major element and some trace element concentrations by wavelength-dispersive X-ray fluorescence spectrometry. Concentrations of some elements in the lanthanide group were determined using the inductively coupled plasma emission spectrometer. Samples were also submitted for analysis by instrumental neutron activation analysis. Determinations of concentrations of U and Pb and isotopic compositions of Pb were done for both whole rock samples and sulfide mineral separates. Major and trace element abundances within different rock types of the Copperton Formation are discussed and compared with those of the Jannelsepan and Hartebeest Pan Formations. The petrogenetic implications of these, the U-Pb isotope systematics and S isotope ratios are used to reconstruct the geological environment of mineralization. 187 refs., 106 figs., 68 tabs

The effect of concentration ratio and type of functional group on synthesis of CNT-ZnO hybrid nanomaterial by an in situ sol-gel process

Science.gov (United States)

Hosseini Largani, Sekineh; Akbarzadeh Pasha, Mohammad

2017-12-01

In this research, MWCNT-ZnO hybrid nanomaterials were synthesized by a simple sol-gel process using Zn(CH3COO)2·2H2O and functionalized MWCNT with carboxyl(COOH) and hydroxyl(OH) groups. Three different mass ratios of MWCNT:ZnO = 3:1, 1:1 and 1:3 were examined. The prepared nanomaterials were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX) and Fourier transform infrared spectroscopy (FTIR). Successful growth of MWCNT-ZnO hybrids for both COOH and OH functional groups and all the three mass ratios were obtained. The ZnO nanoparticles attached on the surfaces of CNTs have rather spherical shapes and hexagonal crystal structure. By increasing the concentration of ZnO, the number and average size of ZnO nanoparticles decorated the body of CNTs in hybrid structures increase. By increasing the ZnO precursor, the distribution of ZnO nanoparticles that appeared on the surface of CNTs becomes more uniform. The SEM observation beside EDX analysis revealed that at the same concentration ratio the amount of ZnO loading on the surface of MWCNT-COOH is more than MWCNT-OH. Moreover, the average size of ZnO nanoparticles attached on the surface of COOH functionalized CNTs is relatively smaller than that of OH functionalized ones.

The electrical, elemental, optical, and surface properties of Si-doped ZnO thin films prepared by thermionic vacuum arc

Science.gov (United States)

Mohammadigharehbagh, Reza; Özen, Soner; Yudar, Hafizittin Hakan; Pat, Suat; Korkmaz, Şadan

2017-09-01

The purpose of this work is to study the properties of Si-doped ZnO (SZO) thin films, which were prepared using the non-reactive thermionic vacuum arc technique. The analysis of the elemental, optical, and surface properties of ZnO:Si thin films was carried out using energy dispersive x-ray spectroscopy, UV-VIS spectrophotometry, atomic force microscopy, and scanning electron microscopy, respectively. The current-voltage measurement was employed in order to study the electrical properties of the films. The effect of Si doping on the physical properties of ZnO films was investigated. The film thicknesses were measured as 55 and 35 nm for glass and PET substrates, respectively. It was clearly observed from the x-ray diffraction results that the Si and ZnO peaks were present in the coated SZO films for all samples. The morphological studies showed that the deposited surfaces are homogenous, dense, and have a uniform surface, with the existence of some cracks only on the glass substrate. The elemental composition has confirmed the existence of Zn, Si, and O elements within the prepared films. Using a UV-VIS spectrophotometer, the optical parameters such as transmittance, absorbance, refractive index, and reflectance were calculated. It should be noted that the transparency and refractive indices obtained from the measurements decrease with increasing Si concentration. The obtained optical bandgap values using transmittance spectra were determined to be 3.74 and 3.84 eV for the glass and PET substrates, respectively. An increase in the bandgap results demonstrates that the Si doping concentration is comparable to the pure ZnO thin films. The current versus voltage curves revealed the ohmic nature of the films. Subsequently, the development and fabrication of excellent transparent conducting electrodes enabled the appropriate use of Si-doped ZnO thin films.

Comparison of two organic fertilizers along with Zn and B elements on concentration, uptake of nutrients and some growth parameters in millet (Panicum miliaceum L.

Directory of Open Access Journals (Sweden)

T Nezhad hoseini

2016-05-01

Full Text Available A field experiment was conducted to study the effect of two organic fertilizers along with zinc and boron elements on some growth parameters, concentration and uptake of nutrients in millet (Panicum miliaceum L. by using factorial based on randomized completely block design with three replications in Qaen region, Iran. The main treatments were municipal solid waste compost and cow manure (each at 0 and 25 t.ha-1 and sub treatments were elements of Zn (0, 50 kg.ha-1 and B (0, 10 kg.ha-1 using their respective ZnSO4 and H3BO3 salts. Results showed that treatments interaction had significant effects on total dry matter yield, number of tillers per plant and plant height of Millet. The highest total dry matter production was achieved by interaction of cow manure along with Zn and B elements. Concentrations of N, Fe, Zn, B and Cu in plant were increased significantly by treatments interaction effects compared to control. Interaction effect of organic fertilizers with B (in the absence of Zn enhanced plant B concentration significantly, whereas, interaction of organic fertilizers with Zn (in the absence of B decreased B concentration in plant. The highest plant uptake of N, P, K, Zn, and B was observed in plots with cow manure and Zn and B elements.

The role of soil biogeochemistry in wine taste: Soil factors influencing grape elemental composition, photosynthetic biomarkers and Cu/Zn isotopic signature of Vitis vinifera

Science.gov (United States)

Blotevogel, Simon; Oliva, Priscia; Darrozes, José; Viers, Jérôme; Audry, Stéphane; Courjault-Radé, Pierre; Orgogozo, Laurent; Le Guedard, Marina; Schreck, Eva

2015-04-01

to the geological difference. These soils differ in elemental compositions and bioavailability of mineral nutrients, preconditions for a potential influence on plants and wine. Elemental ratios of soils are partly transmitted to leaves and grapes of correspondent plants, including nutrients such as Ca. Plant photosynthetic functioning is significantly better on the limestone vineyard due to lower Cu bioavailability: Omega-3 values are negatively linked to Cu bioavailability in corresponding soils. These observations suggest a difference in organic molecule synthesis depending on the vineyard soil, which might include components relevant for taste and fermentation. Cu and Zn isotopic ratios do not differ between both soils. The main fractionation of Cu and Zn isotopes occurs at the soil-plant interface making those isotopes suitable tracers for uptake mechanisms. As a result Zn isotope ratios reveal a strong recycling of Zn in the soil-plant continuum. Our results show a significant influence of soil composition on grape composition, plant biochemistry and potentially wine taste. Determination of organic and sensorial composition of grapes and wine is ongoing and will be discussed in further communications.

Elemental mapping and quantitative analysis of Cu, Zn, and Fe in rat brain sections by laser ablation ICP-MS

Energy Technology Data Exchange (ETDEWEB)

Jackson, Brian [Dartmouth College, Departments of Earth Sciences and Chemistry, Hanover, NH (United States); Harper, Steve [University of Georgia, Savannah River Ecology Laboratory, Aiken, SC (United States); Smith, Laura; Flinn, Jane [George Mason University, Department of Psychology, Fairfax, VA (United States)

2006-02-15

This report details the application of laser ablation quadrupole ICP-MS for the (multi)elemental mapping of 100-{mu}m-thick sections of rat brain. The laser spot size used was 60 {mu}m, and the laser scan speed was 120 {mu}m s{sup -1}. The analysis was relatively rapid, allowing mapping of a whole brain thin section ({approx}1 cm{sup 2}) in about 2 h. Furthermore, the method was amenable to multi-element data collection including the physiologically important elements P and S and afforded sub {mu}g g{sup -1} detection limits for the important trace elements Cu and Zn. Calibrations were performed with pressed pellets of biological certified reference materials, and the elemental distributions and concentrations of Cu, Zn, and Fe were determined in whole rat brain sections. The distributions and concentration ranges for these elements were consistent with previous studies and demonstrate the utility of this technique for rapid mapping of brain thin sections. (orig.)

pH-Dependent Toxicity of High Aspect Ratio ZnO Nanowires in Macrophages Due to Intracellular Dissolution

KAUST Repository

H. Müller, Karin

2010-11-23

High-aspect ratio ZnO nanowires have become one of the most promising products in the nanosciences within the past few years with a multitude of applications at the interface of optics and electronics. The interaction of zinc with cells and organisms is complex, with both deficiency and excess causing severe effects. The emerging significance of zinc for many cellular processes makes it imperative to investigate the biological safety of ZnO nanowires in order to guarantee their safe economic exploitation. In this study, ZnO nanowires were found to be toxic to human monocyte macrophages (HMMs) at similar concentrations as ZnCl2. Confocal microscopy on live cells confirmed a rise in intracellular Zn2+ concentrations prior to cell death. In vitro, ZnO nanowires dissolved very rapidly in a simulated body fluid of lysosomal pH, whereas they were comparatively stable at extracellular pH. Bright-field transmission electron microscopy (TEM) showed a rapid macrophage uptake of ZnO nanowire aggregates by phagocytosis. Nanowire dissolution occurred within membrane-bound compartments, triggered by the acidic pH of the lysosomes. ZnO nanowire dissolution was confirmed by scanning electron microscopy/energy-dispersive X-ray spectrometry. Deposition of electron-dense material throughout the ZnO nanowire structures observed by TEM could indicate adsorption of cellular components onto the wires or localized zinc-induced protein precipitation. Our study demonstrates that ZnO nanowire toxicity in HMMs is due to pH-triggered, intracellular release of ionic Zn2+ rather than the high-aspect nature of the wires. Cell death had features of necrosis as well as apoptosis, with mitochondria displaying severe structural changes. The implications of these findings for the application of ZnO nanowires are discussed. © 2010 American Chemical Society.

Source rock identification of sediments using trace element ratios and 13C isotope data - a case study from Pondicherry region

International Nuclear Information System (INIS)

Tirumalesh, K.; Kulkarni, U.P.; Singh, Gursharan; Ramakumar, K.L.; Chidambaram, S.

2012-01-01

Compositional characteristics of source rocks are generally well recorded in sedimentary deposits and provide valuable information about nature of source rocks even though weathering, physical sorting and deposition environment influence the sediment geochemistry. In this paper we report major, trace element and 13 C isotope data of cutting samples collected from Quaternary, Tertiary and Cretaceous formations in Pondicherry area. The distribution patterns and inter elemental correlations are used to identify source rock composition and carbon isotope compositions to understand the sediment deposition conditions. Mineralogy of the bulk sediment indicates presence of Quartz, K-feldspar, Calcite, Mg-calcite, Aragonite and Clay minerals. Compared to upper continental crust values most of these sediments show lower concentration of all elements except Ca and Zn at some depths. The depletion is probably associated with weathering of feldspar and removal of elements through solution. This also increases the proportion of quartz relative to source rock. The ratios of redox sensitive elements (Th/U) infer oxic weathering in shallow sediments. Elemental ratios (La/Sc, Th/Sc, Th/Cr, Th/Co) and ternary plots (La-Th-Sc and Th-Hf-Co) indicate contribution of felsic source rocks with varying degree of weathering. These plots also infer the inherent heterogeneity in the source rocks. Hafnium correlations with other trace elements suggest contribution of Tonalitic rocks in addition to granite to these sediments. The geochemical characteristics of the sediments are found to be similar to that of sediments belonging to similar geology in nearby regions. Presence of shallow marine condition during the sedimentation is inferred from the detrital index (DI) values, which is further supported by the presence of fibrous clay minerals in ESEM scans. This study also brings out the utility of δ 13 C information to reinforce the geochemical and mineralogical inferences. (author)

The accumulation of elements in plants growing spontaneously on small heaps left by the historical Zn-Pb ore mining.

Science.gov (United States)

Stefanowicz, Anna M; Stanek, Małgorzata; Woch, Marcin W; Kapusta, Paweł

2016-04-01

The study evaluated the levels of nine metals, namely Ca, Cd, Fe, K, Mg, Mn, Pb, Tl, and Zn, in soils and tissues of ten plant species growing spontaneously on heaps left by historical mining for Zn-Pb ores. The concentrations of Cd, Pb, Tl, and Zn in heap soils were much higher than in control soils. Plants growing on heaps accumulated excessive amounts of these elements in tissues, on average 1.3-52 mg Cd kg(-1), 9.4-254 mg Pb kg(-1), 0.06-23 mg Tl kg(-1) and 134-1479 mg Zn kg(-1) in comparison to 0.5-1.1 mg Cd kg(-1), 2.1-11 mg Pb kg(-1), 0.02-0.06 mg Tl kg(-1), and 23-124 mg Zn kg(-1) in control plants. The highest concentrations of Cd, Pb, and Zn were found in the roots of Euphorbia cyparissias, Fragaria vesca, and Potentilla arenaria, and Tl in Plantago lanceolata. Many species growing on heaps were enriched in K and Mg, and depleted in Ca, Fe, and Mn. The concentrations of all elements in plant tissues were dependent on species, organ (root vs. shoot), and species-organ interactions. Average concentrations of Ca, K, and Mg were generally higher in shoots than in roots or similar in the two organs, whereas Cd, Fe, Pb, Tl, and Zn were accumulated predominantly in the roots. Our results imply that heaps left by historical mining for Zn-Pb ores may pose a potential threat to the environment and human health.

Determination of chemical state of Al doping element in ZnO layer

International Nuclear Information System (INIS)

Csik, A.; Toth, J.; Lovics, R.; Takats, V.; Hakl, J.; Vad, K.

2011-01-01

Complete text of publication follows. Transparent and conducting oxides (TCO) thin films are very important from the scientific and technological point of view. The coexistence of electrical conductivity and optical transparency in these materials makes it possible to use them in modern technologies: transparent electrodes for flat panel displays and photovoltaic cells, low emissivity windows, transparent thin films transistors, light emitting diodes. One of the important TCO semiconductors is the impurity-doped zinc-oxide (ZnO) layer, for example aluminium doped zinc-oxide layer (AZO), due to its unique physical and chemical properties. It has wide band gap (3.44 eV) and large exciton binding energy (60 meV). ZnO thin layers have a great interest for potential applications in optical and optoelectronic devices. Furthermore, high quality single crystal ZnO wafers has already been available as a result of new developments in ZnO growth technologies with the capability to scale up wafer size, which is an important factor for increasing efficiency of solar cells. Nonetheless, in order to enable the use of ZnO layers with enhanced electrical properties, higher conductivities can be obtained by doping with donor elements such as aluminium, gallium, indium, boron or fluorine. Investigation of p-type doping possibilities, diffusion processes and thermal stability of these layers are in the focus of interest in the interpretation of their optical and electrical properties, and the prediction of their lifetime. In our SNMS/SIMS-XPS laboratory, experiments on TCO layered structures were carried on. Depth profile and chemical state analyses of ZnO/AlO/ZnO layered structures were performed by Secondary Neutral Mass Spectrometry (SNMS) and X-ray photoelectron spectroscopy (XPS). The samples were produced by atomic layer deposition technique with the following layered structure: between a few hundred atomic layers of ZnO was an AlO atomic layer. The SNMS was used for depth

SPECTROSCOPIC STUDIES OF EXTREMELY METAL-POOR STARS WITH THE SUBARU HIGH DISPERSION SPECTROGRAPH. V. THE Zn-ENHANCED METAL-POOR STAR BS 16920-017

International Nuclear Information System (INIS)

Honda, Satoshi; Aoki, Wako; Beers, Timothy C.; Takada-Hidai, Masahide

2011-01-01

We report Zn abundances for 18 very metal-poor stars studied in our previous work, covering the metallicity range -3.2< [Fe/H] <-2.5. The [Zn/Fe] values of most stars show an increasing trend with decreasing [Fe/H] in this metallicity range, confirming the results found by previous studies. However, the extremely metal-poor star BS 16920-017([Fe/H] =-3.2) exhibits a significantly high [Zn/Fe] ratio ([Zn/Fe] = +1.0). Comparison of the chemical abundances of this object with HD 4306, which has similar atmospheric parameters to BS 16920-017, clearly demonstrates a deficiency of α elements and neutron-capture elements in this star, along with enhancements of Mn and Ni, as well as Zn. The association with a hypernova explosion that has been proposed to explain the high Zn abundance ratios found in extremely metal-poor stars is a possible explanation, although further studies are required to fully interpret the abundance pattern of this object.

Experimental study on ZnO-TiO_2 sorbents for the removal of elemental mercury

International Nuclear Information System (INIS)

Qiu, Kunzan; Zhou, Jinsong; Qi, Pan; Zhou, Qixin; Gao, Xiang; Luo, Zhongyang

2017-01-01

ZnO-TiO_2 sorbents synthesized by an impregnation method were characterized through XRD (X-ray diffraction), XPS (X-ray photoelectron spectroscopy) and EDS (Energy dispersive spectrometer) analyses. An experiment concerning the adsorption of Hg0 by ZnO-TiO_2 under a simulated fuel gas atmosphere was then conducted in a benchscale fixed-bed reactor. The effects of ZnO loading amounts and reaction temperatures on Hg"0 removal performance were analyzed. The results showed that ZnO-TiO_2 sorbents exhibited excellent Hg removal capacity in the presence of H2S at 150 .deg. C and 200 .deg. C; 95.2% and 91.2% of Hg0 was removed, respectively, under the experimental conditions. There are two possible causes for the H_2S reacting on the surface of ZnO-TiO_2: (1) H_2S directly reacted with ZnO to form ZnS, (2) H_2S was oxidized to elemental sulfur (S_a_d) by means of active oxygen on the sorbent surface, and then Sad provided active absorption sites for Hg0 to form HgS. This study identifies three reasons why higher temperatures limit mercury removal. First, the reaction between Hg"0 and H_2S is inhibited at high temperatures. Second, HgS, as the resulting product in the reaction of mercury removal, becomes unstable at high temperatures. Third, the desulfurization reaction strengthens at higher temperatures, and it is likely that H_2S directly reacts with ZnO, thus decreasing the Sad on the sorbent surfaces.

Effects of the Ho{sup 3+}/Yb{sup 3+} concentration ratio on the structure and photoluminescence of ZnO films

Energy Technology Data Exchange (ETDEWEB)

Xu, Boxu [School of Materials Science and Engineering, Tianjin Polytechnic University, Tianjin 300387 (China); Wang, Pei [Auditing Department, Tianjin Polytechnic University, Tianjin 300387 (China); Meng, Xiaoqi; Zou, Kaishun [School of Materials Science and Engineering, Tianjin Polytechnic University, Tianjin 300387 (China); Liu, Juncheng, E-mail: jchliu@tjpu.edu.cn [School of Materials Science and Engineering, Tianjin Polytechnic University, Tianjin 300387 (China)

2016-07-15

To improve the efficiency of photoluminescent films, this study investigates the effects of the Ho{sup 3+}/Yb{sup 3+} concentration ratio on the structure and up-conversion photoluminescence of ZnO films prepared by the sol–gel method and the spin-coating technique. ZnO maintained its hexagonal wurtzite structure after doping with rare earth ions. The ZnO films consist of round granules, the average size of which increases as the Ho{sup 3+}/Yb{sup 3+} concentration ratio increases. Once the ratio exceeds 1:2, the film's granules significantly coarsen, and the surface roughness slightly increases. When the film is pumped with a 980-nm laser, two intense emission bands are observed in the up-conversion emission spectrum, with a green band centered at 550 nm and a red band centered at 660 nm, corresponding to the Ho{sup 3+}: {sup 5}S{sub 2}/{sup 5}F{sub 4}→{sup 5}I{sub 8}, and {sup 5}F{sub 5}→{sup 5}I{sub 8} transitions, respectively. In addition, as the Ho{sup 3+}/Yb{sup 3+} concentration ratio increases, the intensity of the film's upconversion luminescence first increases and then decreases, reaching a maximum at a concentration ratio of 1:2, with a peak of about four times the minimum value.

Mechanisms involved in the hydrothermal growth of ultra-thin and high aspect ratio ZnO nanowires

Science.gov (United States)

Demes, Thomas; Ternon, Céline; Morisot, Fanny; Riassetto, David; Legallais, Maxime; Roussel, Hervé; Langlet, Michel

2017-07-01

Hydrothermal synthesis of ZnO nanowires (NWs) with tailored dimensions, notably high aspect ratios (AR) and small diameters, is a major concern for a wide range of applications and still represents a challenging and recurring issue. In this work, an additive-free and reproducible hydrothermal procedure has been developed to grow ultra-thin and high AR ZnO NWs on sol-gel deposited ZnO seed layers. Controlling the substrate temperature and using a low reagent concentration (1 mM) has been found to be essential for obtaining such NWs. We show that the NW diameter remains constant at about 20-25 nm with growth time contrary to the NW length that can be selectively increased leading to NWs with ARs up to 400. On the basis of investigated experimental conditions along with thermodynamic and kinetic considerations, a ZnO NW growth mechanism has been developed which involves the formation and growth of nuclei followed by NW growth when the nuclei reach a critical size of about 20-25 nm. The low reagent concentration inhibits NW lateral growth leading to ultra-thin and high AR NWs. These NWs have been assembled into electrically conductive ZnO nanowire networks, which opens attractive perspectives toward the development of highly sensitive low-cost gas- or bio-sensors.

The Prestudy for Studying Inorganic Nutrient Metabolism in Humans : the Aplication of ICP-MS for Determination of Stable Isotope Ratio of Fe and Zn

International Nuclear Information System (INIS)

Rukihati; Sumadjo

2001-01-01

A method is described for the determination of isotope ratio of Fe and Zn by means of inductively coupled plasma-mass spectrometry (ICP-MS). The mass spectrometer was operated in low resolution mode to provide maximal sensitivity. Typical conditions for operations were: plasma power 0.85 k W, reflected power 56 Fe/ 54 Fe, 57 Fe/ 54 Fe, 58 Fe/ 54 Fe, dan 64 Zn/ 67 Zn, 66 Zn/ 67 Zn, 68 Zn/ 67 Zn, 70 Zn/ 67 Zn measured by ICP-MS showed a good level of agreement with TIMS (thermal ionization mass spectrometry). This method was prepared for studying the absorption and/or metabolism of inorganic nutrients in humans. (author)

Evaluation of CF/CM, concentration ratios for elements in fetus to mother, using cord blood and maternal blood

International Nuclear Information System (INIS)

Watanabe, Y.; Yukawa, M.; Kim, H.S.; Nishimura, Y.; Osada, H.; Sekiya, S.

2000-01-01

ICRP recommends age-dependent dose evaluation for intakes of radionuclides by inhalation and ingestion, and gave age-specific biokinetic models and dose coefficients (doses per unit intake) for infants, children and adults in the publications. Dose coefficients are also needed for the assessment of exposures received in utero and after birth by the offspring of the woman who has received intakes of radionuclides. In the model that has been adopted by ICRP, the doses to the developing fetus are calculated using CF/CM values, concentration ratios for radionuclides in the fetus and the maternal tissues. The purpose of this study is to evaluate the CF/CM of each radionuclide by the measurement of element concentration in cord blood and maternal blood. Blood samples were obtained from 35 mothers who delivered in Department of Obstetrics and Gynecology of Chiba University. Just after the delivery, unbiblical cord blood was sampled. Maternal blood was also obtained from the arm vein within 30 minutes after the delivery. The serum was separated from the blood sample with centrifugation. About 50 mg of freezer-dried whole blood and serum were digested with 0.5 ml of 65% ultra-pure nitric acid and 0.2 ml of 30% hydrogen peroxide in a microwave digester. The diluted solutions were used for the determination of elements by ICP-MS (Inductively Coupled Plasma Mass Spectrometry) and ICP-AES (Inductively Coupled Plasma Atomic Emission Spectrometry). The elements determined in these samples included Mg, K, Ca, Mn, Fe, Cu, Zn, Se, Rb, Sr and Cs. The concentration of Cu was higher in the maternal blood than in the cord blood in both whole blood and serum. On the other hand, Mn and Fe were higher in the cord blood. The differences of concentration ratios among elements and the differences among tissues will be discussed. (author)

Optical properties and surface morphology of ZnTe thin films prepared by multiple potential steps

Energy Technology Data Exchange (ETDEWEB)

Gromboni, Murilo F.; Lucas, Francisco W. S.; Mascaro, Lucia H., E-mail: lmascaro@ufscar.br [Universidade de Federal de Sao Carlos (LIEC/UFSCar), SP (Brazil). Departamento de Quimica. Lab. de Eletroquimica e Ceramica

2014-03-15

In this work, the ZnTe thin films were electrodeposited using potentiostatic steps, on Pt substrate. The effect of steps number, the deposition time for each element (Zn or Te) and layer order (Zn/Te or Te/Zn) in the morphology, composition, band gap energy and photocurrent was evaluated. Microanalysis data showed that the ratio Zn/Te ranged from 0.12 and 0.30 and the film was not stoichiometric. However, the band-gap value obtained from in all experimental conditions used in this work was 2.28 eV, indicating film growth of ZnTe. The samples with higher Zn showed higher photocurrent, which was of the order of 2.64 μA cm{sup -2} and dendritic morphology (author)

Transfer factors of some selected radionuclides (radioactive Cs, Sr, Mn, Co and Zn) from soil to leaf vegetables

International Nuclear Information System (INIS)

Ban-nai, Tadaaki; Muramatsu, Yasuyuki; Yanagisawa, Kei

1995-01-01

Transfer factors of radionuclides from soil to leaf vegetables (cabbage, Chinese cabbage, komatsuna, spinach and lettuce) have been studied by radiotracer experiments using Andosol as a representative of Japanese soils. The transfer factors of radioactive Cs, Sr, Mn, Co and Zn for edible parts of vegetables (average of five vegetables) were 0.11, 0.24, 0.61, 0.05 and 0.52, respectively. These values should be used in safety assessment for Japanese agricultural environment. The transfer factors of Mn, Co and Zn for spinach were higher than those for the other vegetables. The transfer factors of Cs for different organs of the leaf vegetables were rather homogeneous. The transfer factors of Sr and Mn were higher for older (outer) leaves than younger (inner) ones. In contrast to Sr and Mn, transfer factors of Zn for younger leaves were higher than those for older ones. The distribution ratios of the elements between soil-solution and soil were in the order Sr>Mn>Cs>Co>Zn, whereas the distribution ratios of the elements between plant and soil-solution were in the order Zn>Cs>Mn>Co>Sr. These results indicate that the selectivity for Sr by plants from the soil-solution was low and that for Zn was very high. (author)

Bioaccumulation of trace elements by Avicennia marina

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Kandasamy Kathiresan

2014-11-01

Full Text Available Objective: To analyze the concentrations of 12 micro-nutrients (Al, B, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, and Zn in different plant parts of Avicennia marina and its rhizosphere soil of the south east coast of India. Methods: The samples were acid digested, then analyzed by using inductively coupled plasma system (ICP-Optical Emission Spectrophotometer. Results: Levels of metals were found in the decreasing order: Cd>Co>Ni>Pb>B >Cr>Zn>Mg>Mn>Cu>Fe>Al. The soil held more levels of metals than plant parts, but within the permissible limits of concentration. Bark and root accumulated higher levels of trace elements in a magnitude of 10-80 folds than other plant parts. The overall bioaccumulation factor in the sampling sites of Vellar, Pichavaram and Cuddalore was 2.88, 1.42 0.47 respectively. Essential elements accumulate high in mature mangroves forest while non-essential elements accumulate high in the industrially polluted mangroves. Conclusions: The ratio between essential and non-essential elements was found higher in young mangrove forest than that in mature mangrove forest and polluted mangrove areas. Thus, the ratio of accumulation can be used as an index of the growth and pollution status of mangroves.

Alterations of serum antioxidant trace elements (Se, Zn and Cu status in patients with cutaneous leishmaniasis

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Leila Farzin

2014-02-01

Full Text Available Objective: To assess the serum antioxidant trace elements selenium (Se, zinc (Zn and copper (Cu in cutaneous leishmaniasis patients. Methods: In this study, serum Se, Zn and Cu was determined by using atomic absorption spectrometry in patients with cutaneous leishmaniasis (n=95. The values were statistically compared between patients and control group (n=100 using One-way analysis of variance (ANOVA. Results: Our results showed that there was a significant difference in the values of Se and Zn between two groups (P0.05. Se and Zn levels were found to be (4.33依1.06 and (70.23依19.12 µg/dL in cutaneous leishmaniasis cases, and these values were found statistically lower compared to the controls (11.10依2.37 and (119.61依26.18 µg/dL, respectively. Conclusions: The observations that host products are released from stimulated leukocytes and could induce metabolic changes similar to an acute-phase response revealed an endocrine role for the immune system. Characteristic changes in trace-mineral metabolism are an integral part of the acute-phase response. The changes are usually reflected in decreased serum Se and Zn concentrations.

Nonlinear Finite Element Analysis of Shells with Large Aspect Ratio

Science.gov (United States)

Chang, T. Y.; Sawamiphakdi, K.

1984-01-01

A higher order degenerated shell element with nine nodes was selected for large deformation and post-buckling analysis of thick or thin shells. Elastic-plastic material properties are also included. The post-buckling analysis algorithm is given. Using a square plate, it was demonstrated that the none-node element does not have shear locking effect even if its aspect ratio was increased to the order 10 to the 8th power. Two sample problems are given to illustrate the analysis capability of the shell element.

Elemental ratios for characterization of quantum-dots populations in complex mixtures by asymmetrical flow field-flow fractionation on-line coupled to fluorescence and inductively coupled plasma mass spectrometry

International Nuclear Information System (INIS)

Menendez-Miranda, Mario; Fernandez-Arguelles, Maria T.; Costa-Fernandez, Jose M.; Encinar, Jorge Ruiz; Sanz-Medel, Alfredo

2014-01-01

Highlights: • The hyphenated system allows unequivocal identification of nanoparticle populations. • AF4 separation permitted detection of unexpected nanosized species in a sample. • ICP-QQQ provides elemental ratios with adequate accuracy in every nanoparticle. • Purity and chemical composition of different quantum dot samples were assessed. - Abstract: Separation and identification of nanoparticles of different composition, with similar particle diameter, coexisting in heterogeneous suspensions of polymer-coated CdSe/ZnS quantum dots (QDs) have been thoroughly assessed by asymmetric flow field-flow fractionation (AF4) coupled on-line to fluorescence and inductively coupled plasma mass spectrometry (ICPMS) detectors. Chemical characterization of any previously on-line separated nanosized species was achieved by the measurement of the elemental molar ratios of every element involved in the synthesis of the QDs, using inorganic standards and external calibration by flow injection analysis (FIA). Such elemental molar ratios, strongly limited so far to pure single nanoparticles suspensions, have been achieved with adequate accuracy by coupling for the first time an ICP-QQQ instrument to an AF4 system. This hyphenation turned out to be instrumental to assess the chemical composition of the different populations of nanoparticles coexisting in the relatively complex mixtures, due to its capabilities to detect the hardly detectable elements involved in the synthesis. Interestingly such information, complementary to that obtained by fluorescence, was very valuable to detect and identify unexpected nanosized species, present at significant level, produced during QDs synthesis and hardly detectable by standard approaches

Effects of Mo, Zn, Sr and Ba loads on these elements' uptake and oil content and fatty acid composition of rapeseed

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Kastori Rudolf R.

2003-01-01

Full Text Available Studied in the present paper were the long-term effects of the application of high Mo, Zn, Sr and Ba rates (0, 90, 270, and 810 kg ha-1 on rapeseed oil content and oil fatty acid composition. The trace elements were applied in the spring of 1991, while the rapeseed was sown on a calcareous сhernozem soil in 2001. The trace elements differed significantly in their rates of accumulation in rapeseed plants. Relative to the control, the Mo content of the stem increased up to 1,000 times, that of the chaff over 100 times, and that of the seed around 60 times. The levels of the other trace elements increased considerably less relative to the control. The increases were typically twofold to threefold, depending on the plant part involved. The trace elements accumulated the most in the vegetative plant parts, except for Zn, a major quantity of which was found in the seed as well. The application of the high rates of Sr, Zn and, to an extent. Mo reduced the seed oil content of rapeseed. However, the differences were not statistically significant. The application of the trace elements had no significant effect on the fatty acid composition of the rapeseed oil, either. The increased levels of the trace elements found in the rapeseed plants indicate that 11 years after application significant amounts of the applied elements are still present in the soil in a form available to plants. However, the rates were not high enough to affect the synthesis of oil and its fatty acid composition.

Experimental study on ZnO-TiO{sub 2} sorbents for the removal of elemental mercury

Energy Technology Data Exchange (ETDEWEB)

Qiu, Kunzan; Zhou, Jinsong; Qi, Pan; Zhou, Qixin; Gao, Xiang; Luo, Zhongyang [Zhejiang University, Hangzhou (China)

2017-09-15

ZnO-TiO{sub 2} sorbents synthesized by an impregnation method were characterized through XRD (X-ray diffraction), XPS (X-ray photoelectron spectroscopy) and EDS (Energy dispersive spectrometer) analyses. An experiment concerning the adsorption of Hg0 by ZnO-TiO{sub 2} under a simulated fuel gas atmosphere was then conducted in a benchscale fixed-bed reactor. The effects of ZnO loading amounts and reaction temperatures on Hg{sup 0} removal performance were analyzed. The results showed that ZnO-TiO{sub 2} sorbents exhibited excellent Hg removal capacity in the presence of H2S at 150 .deg. C and 200 .deg. C; 95.2% and 91.2% of Hg0 was removed, respectively, under the experimental conditions. There are two possible causes for the H{sub 2}S reacting on the surface of ZnO-TiO{sub 2}: (1) H{sub 2}S directly reacted with ZnO to form ZnS, (2) H{sub 2}S was oxidized to elemental sulfur (S{sub ad}) by means of active oxygen on the sorbent surface, and then Sad provided active absorption sites for Hg0 to form HgS. This study identifies three reasons why higher temperatures limit mercury removal. First, the reaction between Hg{sup 0} and H{sub 2}S is inhibited at high temperatures. Second, HgS, as the resulting product in the reaction of mercury removal, becomes unstable at high temperatures. Third, the desulfurization reaction strengthens at higher temperatures, and it is likely that H{sub 2}S directly reacts with ZnO, thus decreasing the Sad on the sorbent surfaces.

ZnO/Cu/ZnO multilayer films: Structure optimization and investigation on photoelectric properties

International Nuclear Information System (INIS)

Liu Xiaoyu; Li Yingai; Liu Shi; Wu Honglin; Cui Haining

2012-01-01

A series of ZnO/Cu/ZnO multilayer films has been fabricated from zinc and copper metallic targets by simultaneous RF and DC magnetron sputtering. Numerical simulation of the optical properties of the multilayer films has been carried out in order to guide the experimental work. The influences of the ZnO and Cu layer thicknesses, and of O 2 /Ar ratio on the photoelectric and structural properties of the films were investigated. The optical and electrical properties of the multilayers were studied by optical spectrometry and four point probe measurements, respectively. The structural properties were investigated using X-ray diffraction. The performance of the multilayers as transparent conducting coatings was compared using a figure of merit. In experiments, the thickness of the ZnO layers was varied between 4 and 70 nm and those of Cu were between 8 and 37 nm. The O 2 /Ar ratios range from 1:5 to 2:1. Low sheet resistance and high transmittance were obtained when the film was prepared using an O 2 /Ar ratio of 1:4 and a thickness of ZnO (60 nm)/Cu (15 nm)/ZnO (60 nm). - Highlights: ► ZnO/Cu/ZnO films were fabricated from zinc and copper targets by sputtering. ► Transmittance reaches maximum when top and bottom ZnO thicknesses are nearly equal. ► Sheet resistance increases with increasing ZnO layer thickness. ► Variation in sheet resistance with oxygen/argon ratio is due to interface effect.

Cytotoxicity evaluation of ZnO-eugenol (ZOE) using different ZnO structure on human gingival fibroblast

Science.gov (United States)

Bakhori, Siti Khadijah Mohd; Mahmud, Shahrom; Masudi, Sam'an Malik; Seeni, Azman; Mohamad, Dasmawati; Ann, Ling Chuo; Sirelkhatim, Amna

2017-07-01

Application of ZnO is widely used in many industries, such as in optoelectronic devices, automotive, textile, cosmetics, medical and dentistry. In this study, emphasis was given on ZnO-eugenol (ZOE) that has been used in dental restoration. ZOE contained 80% ZnO and 20% eugenol. ZOE exhibited selective toxicity that could kill bacteria but safe on human cells. The safety of ZOE on humans is critically important. Two types of ZnO with different morphology, namely ZnO-A and ZnO-K were used to make ZOE (ZOE-A and ZOE-K) and the cytotoxicity level on human gingival fibroblast (HGF) cell line were evaluated. Both ZnO were characterized for its morphology and structural using Field Emission Scanning Electron Microscopy (FESEM) and X-ray Diffraction (XRD), respectively. The cytotoxicity level was evaluated using CCK-8 assay where the percentage of viable cells after 72 h were observed. The result showed ZnO-A, containing mostly rod-like shape with a crystallite size of 37.5 nm, had a higher percentage of viable cells after 72 h. Sample ZnO-K, containing irregular shape morphology with bigger crystallite size of 42.2 nm, had a lower percentage of viable cells after 72 h. The HGF cell line was treated with extract dilution of ZOE-A and ZOE-K at 5, 10 and 15%, respectively. At 15% of extracts dilution, 97.3% of the HGF cells survived (for ZOE-A) while the survival percentage of ZOE-K was only 88.1%. This fact was probably due to the larger surface-to-volume ratio of ZnO-A that gave better interlocking bond in ZOE-A. This interlocking bond can prevent the ZnO and eugenol elements leaching out from the ZOE matrix thereby decrease in cytotoxicity effects on HGF.

Assessment Cu, Ni and Zn Pollution in the Surface Sediments in the Southern Peninsular Malaysia using Cluster Analysis, Ratios of Geochemical Nonresistant to Resistant Fractions, and Geochemical Indices

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Yap. C. K.

2011-01-01

Full Text Available The intertidal sediment samples collected in May 2007 from 12 sampling sites in the southern part of Peninsular Malaysia, were determined for the total concentrations of Cu, Ni and Zn and their four geochemical fractions. The total concentrations (μg/g dry weight of Cu, Ni and Zn ranged from 9.48 to 115.82, 12.95 to 36.18 and 45.35 to 136.56, respectively. The ratios of nonresistant to resistant fractions based on geochemical analysis revealed that the Pantai Lido and Senibong had > 1.0, indicating > 50% of the total concentrations of Cu, Ni and Cu were contributed by anthropogenic sources. This is well complemented by the cluster analysis in which Pantai Lido and Senibong are clustered together based on the three metals clustering pattern. By using Fe as a normalizing element, Cu found at Pantai Lido and Senibong showed > 1.5 for the enrichment factor (EF, which indicated that the Cu was delivered from non-crustal materials or anthropogenic origins while all sampling sites showed Ni and Zn may be entirely from crustal materials. Based on the geoaccumulation index (Igeo (Müller, 1981, similar pattern was also found for Pantai Lido and Senibong in which again only Cu concentrations ranged from 1-2, indicating 'moderate pollution' (Igeo 1 < 2; Class 2.while other sites can be considered as 'unpolluted' (Igeo < 0; Class 0 by Cu, Ni and Zn. Ratios of NR/R exhibited better in the assessment of polluted sites while EF and Igeo should be revised according to Malaysian sedimentary characteristics. This study should prompt more biochemical and molecular studies on the intertidal molluscs from the Straits of Johore since the identified two sites are located in the Straits of Johore, especially the commercial mussel, Perna viridis.

Luminescent, magnetic and optical properties of ZnO-ZnS nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Raleaooa, Pule V. [Department of Physics, University of the Free State, ZA 9300 Bloemfontein (South Africa); Department of Chemistry, University of the Free State, ZA 9300 (South Africa); Roodt, Andreas [Department of Chemistry, University of the Free State, ZA 9300 (South Africa); Mhlongo, Gugu G.; Motaung, David E. [DST/CSIR Nanotechnology Innovation Center, National Center for Nano-Structured Materials, Council for Scientific and Industrial Research, P.O. Box 395, ZA 0001 Pretoria (South Africa); Kroon, Robin E. [Department of Physics, University of the Free State, ZA 9300 Bloemfontein (South Africa); Ntwaeaborwa, Odireleng M., E-mail: ntwaeab@gmail.com [School of Physics, University of the Witwatersrand, Private Bag 3, Wits, ZA 2050 (South Africa)

2017-02-15

The structure, particle morphology, optical and magnetic properties of ZnO, ZnS and ZnO-ZnS nanoparticles prepared by the sol-gel method are reported. ZnO and ZnS were combined at room temperature by an ex situ synthetic route to prepare ZnO-ZnS nanocomposites. The nanocomposites exhibited particle morphology different from that of ZnO and ZnS nanoparticles. The ZnO and ZnS nanoparticles exhibited quantum confinement as inferred from the widening of their respective bandgap energies. The electron paramagnetic resonance data provided evidence for the existence of magnetic clusters near the surface, electron to nuclei interactions and defect states. The ZnO-ZnS nanocomposites exhibited tunable emission that was dependent on the ratio of ZnO to ZnS. These composites were evaluated for application in different types of light emitting devices.

Elemental and isotopic characterization of Japanese and Philippine polished rice samples using instrumental neutron activation analysis and isotope ratio mass spectrometry

International Nuclear Information System (INIS)

Pabroa, Preciosa Corazon B.; Sucgang, Raymond J.; Mendoza, Norman dS.; Ebihara, Mitsuru

2011-01-01

Rice is a staple food for most Asian countries such as the Philippines and Japan and as such its elemental and isotopic content are of interest to the consumers. Its elemental content may reflect the macro nutrient reduction during milling or probable toxic elements uptake. Three Japanese and four Philippine polished rice samples in his study mostly came from rice bought from supermarkets.These rice samples were washed, dried and ground to fine powder. Instrumental neutron activation analysis (INAA), a very sensitive non-destructive multi-element analytical technique, was used for the elemental analysis of the samples and isotope-ratio mass spectrometry (IRMS) was used to obtain the isotopic signatures of the samples. Results show that compared with the unpolished rice standard NIES CRM10b, the polished Japanese and Philippine rice sampled show reduced concentrations of elements by as much as 1/3 to 1/10 of Mg, Mn, K and Na. Levels of Ca and Zn are not greatly affected. Arsenic is found in all the Japanese rice tested at an average concentration of 0.103 μg/g and three out of four of the Philippine rice at an average concentration of 0.070 μg/g. Arsenic contamination may have been introduced from the fertilizer used in rice fields. Higher levels of Br are seen in two of the Philippine rice at 14 and 34 μg/g with the most probable source being the pesticide methyl bromide. Isotopic ratio of ae 13 C show signature of a C3 plant with possible narrow distinguishable signature of Japanese rice within -27.5 to -28.5 while Philippine rice within -29 to -30. More rice samples will be analyzed to gain better understanding of isotopic signatures to distinguish inter-varietal and/or geographical differences. Elemental composition of soil samples of rice samples sources will be determined for better understanding of uptake mechanisms. (author)

INFLUENCE OF IONIZING IRRADIATION ON THE PARAMETERS OF ZN NANOTUBES ARRAYS FOR DESIGN OF FLEXIBLE ELECTRONICS ELEMENTS

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D. B. Kadyrzhanov

2018-01-01

Full Text Available The aim of the study is establishing the possibility of using Zn nanotube arrays as a basis for design compact and lightweight elements of flexible electronics, including operating under influence of ionizing irradiation.The paper presents the results of the synthesis of Zn nanotubes obtained by electrochemical deposition in the pores of polymer matrices and the study of their structural and electrophysical properties after directional modification by ionizing radiation with different doses. Using the methods of scanning electron microscopy, X-ray diffraction and energy dispersive analysis, the structure of nanotubes having a polycrystalline structure and completely consisting of zinc was studied and it was demonstrated that irradiation with Ar8+ ions with a dose from 1 × 109 to 5 × 1011 ion/cm2 and energy 1.75 MeV/nucleon has an effect on the crystal structure of nanotubes.At high doses, localized highly defect zones arise, leading to a critical change in the structure and physical properties of the nanotubes, respectively. It is shown that the consequence of the modification of the crystal structure is a change in the electrical conductivity of nanotubes: at low doses the electrical conductivity increases, but when the threshold value is reached, it sharply decreases. The change in the crystal structure and the corresponding changes in the conductive properties of Zn nanotubes due to irradiation determine the mechanism of ionizing radiation influence on nanomaterials and determine the possibility of using Zn nanotubes arrays as a basis for creating compact and lightweight elements of flexible electronics.

Distribution of P, K, Ca, Mg, Cd, Cu, Fe, Mn, Pb and Zn in wood and bark age classes of willows and poplars used for phytoextraction on soils contaminated by risk elements.

Science.gov (United States)

Zárubová, Pavla; Hejcman, Michal; Vondráčková, Stanislava; Mrnka, Libor; Száková, Jiřina; Tlustoš, Pavel

2015-12-01

Fast-growing clones of Salix and Populus have been studied for remediation of soils contaminated by risk elements (RE) using short-rotation coppice plantations. Our aim was to assess biomass yield and distributions of elements in wood and bark of highly productive willow (S1--[Salix schwerinii × Salix viminalis] × S. viminalis, S2--Salix × smithiana clone S-218) and poplar (P1--Populus maximowiczii × Populus nigra, P2--P. nigra) clones with respect to aging. The field experiment was established in April 2008 on moderately Cd-, Pb- and Zn- contaminated soil. Shoots were harvested after four seasons (February 2012) and separated into annual classes of wood and bark. All tested clones grew on contaminated soils, with highest biomass production and lowest mortality exhibited by P1 and S2. Concentrations of elements, with exception of Ca and Pb, decreased with age and were higher in bark than in wood. The Salix clones were characterised by higher removal of Cd, Mn and Zn compared to the Populus clones. Despite generally higher RE content in young shoots, partly due to lower wood/bark ratios and higher RE concentrations in bark, the overall removal of RE was higher in older wood classes due to higher biomass yield. Thus, longer rotations seem to be more effective when phytoextraction strategy is considered. Of the four selected clones, S1 exhibited the best removal of Cd and Zn and is a good candidate for phytoextraction.

Acceptors related to group I elements in ZnO ceramics

Energy Technology Data Exchange (ETDEWEB)

Kushnirenko, V.I. [V. Lashkarev Institute of Semiconductor Physics, NAS of Ukraine, Pr. Nauky 45, Kiev 03028 (Ukraine); Markevich, I.V., E-mail: ivmarkevich@ukr.net [V. Lashkarev Institute of Semiconductor Physics, NAS of Ukraine, Pr. Nauky 45, Kiev 03028 (Ukraine); Zashivailo, T.V. [National Technical University of Ukraine ' KPI' , Pr. Pobedy 37, Kiev 03056 (Ukraine)

2012-08-15

ZnO ceramics doped with Li, Na or K were sintered in air for 4 h at 1000 Degree-Sign C. Electrical conductivity as well as photoluminescence (PL), PL excitation and photoconductivity spectra were measured and compared with those in undoped samples. The influence of both fast and slow cooling of the samples from 1000 Degree-Sign C on measured characteristics was investigated. The yellow-orange PL bands associated with the deep acceptors Li{sub Zn}, Na{sub Zn} and K{sub Zn} were observed and the corresponding PL excitation spectra were determined. These acceptors were found to form some complexes with other lattice defects. - Highlights: Black-Right-Pointing-Pointer Centers related to Li, Na and K impurities in zinc oxide were investigated. Black-Right-Pointing-Pointer It was shown that Li{sub Zn}, Na{sub Zn} and K{sub Zn} centers were deep acceptors responsible for yellow-orange PL bands. Black-Right-Pointing-Pointer These acceptors were found to form some complexes with other lattice defects. Black-Right-Pointing-Pointer The formation of shallow acceptors due to doping ZnO ceramics with Li, Na and K was not found.

Trace elements in scalp hair of leukaemia patients

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Khuder Ali

2014-08-01

Full Text Available The aim of this study was to determine the concentration of Fe, Ni, Cu, Zn and Pb in scalp hair of leukaemia patients and healthy volunteers, using the optimised XRF method. Leukaemia hair samples were classifi ed corresponding to type, growth and age of the participants. The results showed that the studied trace elements (TEs in both of leukaemia and control groups were positively skewed. In comparison with the control group, lower Fe, Cu, Zn and Pb and higher of Ni medians were found in all studied leukaemia patients. The median rank obtained by Mann-Whitney U-test revealed insignifi cant differences between the leukaemia patients subgroups and the controls. An exact probability (α 0.70 in the scalp hair of control group were observed between Ni/Fe-Ni, Cu/Fe-Cu, Zn/Fe-Zn, Pb/Fe-Pb, Cu/Ni-Zn/Ni, Cu/Ni-Pb/Ni, Zn/Ni-Pb/Ni, Zn/Fe-Zn/Cu, Pb/Ni-Ni and Ni/Fe-Pb/Ni, whereas only very strong positive ratios in the scalp hair of leukaemia patients group were observed between Ni/Fe-Ni, Cu/Fe-Cu, Zn/Fe-Zn and Pb/Fe-Pb, all correlations were signifi cant at p < 0.05. Other strong and signifi cant correlations were also observed in scalp hair of both groups. Signifi cant differences between grouping of studied TEs in all classifi ed leukaemia groups and controls were found using principal component analysis (PCA. The results of PCA confi rmed that the type and the growth of leukaemia factors were more important in element loading than the age factor.

Elemental ratios for characterization of quantum-dots populations in complex mixtures by asymmetrical flow field-flow fractionation on-line coupled to fluorescence and inductively coupled plasma mass spectrometry.

Science.gov (United States)

Menendez-Miranda, Mario; Fernandez-Arguelles, Maria T; Costa-Fernandez, Jose M; Encinar, Jorge Ruiz; Sanz-Medel, Alfredo

2014-08-11

Separation and identification of nanoparticles of different composition, with similar particle diameter, coexisting in heterogeneous suspensions of polymer-coated CdSe/ZnS quantum dots (QDs) have been thoroughly assessed by asymmetric flow field-flow fractionation (AF4) coupled on-line to fluorescence and inductively coupled plasma mass spectrometry (ICPMS) detectors. Chemical characterization of any previously on-line separated nanosized species was achieved by the measurement of the elemental molar ratios of every element involved in the synthesis of the QDs, using inorganic standards and external calibration by flow injection analysis (FIA). Such elemental molar ratios, strongly limited so far to pure single nanoparticles suspensions, have been achieved with adequate accuracy by coupling for the first time an ICP-QQQ instrument to an AF4 system. This hyphenation turned out to be instrumental to assess the chemical composition of the different populations of nanoparticles coexisting in the relatively complex mixtures, due to its capabilities to detect the hardly detectable elements involved in the synthesis. Interestingly such information, complementary to that obtained by fluorescence, was very valuable to detect and identify unexpected nanosized species, present at significant level, produced during QDs synthesis and hardly detectable by standard approaches. Copyright © 2014. Published by Elsevier B.V.

Factors affecting trace element content in periurban market garden subsoil in Yunnan Province, China.

Science.gov (United States)

Zu, Yanqun; Bock, Laurent; Schvartz, Christian; Colinet, Gilles; Li, Yuan

2011-01-01

Field investigations were conducted to measure subsoil trace element content and factors influencing content in an intensive periurban market garden in Chenggong County, Yunnan Province, South-West China. The area was divided into three different geomorphological units: specifically, mountain (M), transition (T) and lacustrine (L). Mean trace element content in subsoil were determined for Pb (58.2 mg/kg), Cd (0.89 mg/kg), Cu (129.2 mg/kg), and Zn (97.0 mg/kg). Strong significant relationships between trace element content in topsoil and subsoil were observed. Both Pb and Zn were accumulated in topsoil (RTS (ratio of mean trace element in topsoil to subsoil) of Pb and Zn > or =1.0) and Cd and Cu in subsoil (RTS of Cd and Cu related to relief, stoniness, soil color, clay content, and cation exchange capacity. Except for 7.5 YR (yellow-red) color, trace element content increased with color intensity from brown to reddish brown. Significant positive relationships were observed between Fe content and that of Pb and Cu. Trace element content in mountain unit subsoil was higher than in transition and lacustrine units (M > T > L), except for Cu (T > M > L). Mean trace element content in calcareous subsoil was higher than in sandstone and shale. Mean trace element content in clay texture subsoil was higher than in sandy and sandy loam subsoil, and higher Cu and Zn content in subsoil with few mottles. It is possible to model Pb, Cd, Cu, and Zn distribution in subsoil physico-chemical characteristics to help improve agricultural practice.

Effects of KOH:ZnCl2 mole ratio on the phase formation, morphological and inhibitive properties of potassium zinc phosphate (PZP) pigments

International Nuclear Information System (INIS)

Askari, F.; Ghasemi, E.; Ramezanzadeh, B.; Mahdavian, M.

2015-01-01

Graphical abstract: This figure illustrates the inhibition mechanism. The film precipitation on the anodic and cathodic regions of the metal surface causes a drop in dissolution rate of steel. - Highlights: • We synthesized the ZP pigments via coprecipitation method. • Effect of KOH:ZnCl 2 on phase formation, morphology and inhibitive performance of pigment. • KOH:ZnCl 2 ratio is effective on phase formation and morphology of ZP pigments. • KZn 2 H(PO 4 ) 2 phase showed superior corrosion inhibition behavior than KZnPO 4 . - Abstract: Different types of potassium zinc phosphate (PZP) pigments were synthesized by a co-precipitation method. The PZPs were obtained through changing KOH:ZnCl 2 mole ratio. The chemical composition of the pigments was studied by X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy (SEM). Then, the extracts of the PZPs were prepared in 3.5% (w/w) NaCl solution. The inhibitive performance of the pigments was investigated by polarization technique and SEM surface analysis through dipping mild steel panels in the pigment extracts for different immersion times. Results showed that changing ZnCl 2 /KOH mole ratio could influence formation of KZn 2 H(PO 4 ) 2 and KZnPO 4 phases. It was known that the KZn 2 H(PO 4 ) 2 phase has a superior corrosion inhibition behavior in 3.5% NaCl solution than KZnPO 4 phase

Incorporation of trace elements in Portland cement clinker: Thresholds limits for Cu, Ni, Sn or Zn

International Nuclear Information System (INIS)

Gineys, N.; Aouad, G.; Sorrentino, F.; Damidot, D.

2011-01-01

This paper aims at defining precisely, the threshold limits for several trace elements (Cu, Ni, Sn or Zn) which correspond to the maximum amount that could be incorporated into a standard clinker whilst reaching the limit of solid solution of its four major phases (C 3 S, C 2 S, C 3 A and C 4 AF). These threshold limits were investigated through laboratory synthesised clinkers that were mainly studied by X-ray Diffraction and Scanning Electron Microscopy. The reference clinker was close to a typical Portland clinker (65% C 3 S, 18% C 2 S, 8% C 3 A and 8% C 4 AF). The threshold limits for Cu, Ni, Zn and Sn are quite high with respect to the current contents in clinker and were respectively equal to 0.35, 0.5, 0.7 and 1 wt.%. It appeared that beyond the defined threshold limits, trace elements had different behaviours. Ni was associated with Mg as a magnesium nickel oxide (MgNiO 2 ) and Sn reacted with lime to form a calcium stannate (Ca 2 SnO 4 ). Cu changed the crystallisation process and affected therefore the formation of C 3 S. Indeed a high content of Cu in clinker led to the decomposition of C 3 S into C 2 S and of free lime. Zn, in turn, affected the formation of C 3 A. Ca 6 Zn 3 Al 4 O 15 was formed whilst a tremendous reduction of C 3 A content was identified. The reactivity of cements made with the clinkers at the threshold limits was followed by calorimetry and compressive strength measurements on cement paste. The results revealed that the doped cements were at least as reactive as the reference cement.

Cd induced redistribution of elements within leaves of the Cd/Zn hyperaccumulator Thlaspi praecox as revealed by micro-PIXE

International Nuclear Information System (INIS)

Pongrac, Paula; Vogel-Mikus, Katarina; Vavpetic, Primoz; Tratnik, Janja; Regvar, Marjana; Simcic, Jurij; Grlj, Natasa; Pelicon, Primoz

2010-01-01

A detailed localisation of elements within leaf tissues of hydroponically grown Cd/Zn hyperaccumulator Thlaspi praecox (Brassicaceae) was determined by micro-PIXE at Jozef Stefan Institute (Ljubljana, Slovenia) in order to study accumulation patterns of Cd and other elements in the case of a single metal (Cd) pollution. Plants were treated with increasing concentrations of Cd in the solution (0 (control), 1, 10 and 100 μM). As expected, concentration of Cd in the leaves gradually increased with Cd concentration in the solution. In order to reveal the main Cd storage compartment space within the leaves a relative element distribution (pool) was calculated based on concentrations of elements in specific leaf tissues and their weight portions. Where present at detectable levels, Cd accumulated in the epidermal tissues (at 10 μM), but the contribution of epidermal pool decreased with increasing Cd concentration in solution (at 100 μM). The opposite was observed for the mesophyll pool. In addition, in Cd treated plants, a significant decrease in mesophyll Fe pool and an increase in the epidermal Fe pool were observed. Similar effect was seen for Mn pool at 100 μM Cd treatment accompanied by increasing Zn epidermal pool with increasing Cd in nutrient solution. Altogether these results indicate repartitioning of essential mesophyll cation pools (e.g., Fe, Mn and possibly Zn) when increasing Cd contents, that are instead more intensively stored in the epidermal cells. These results confirmed micro-PIXE as effective and powerful technique providing essential information on metal localisation, repartitioning and major elemental stores in plants on the tissue levels that were not accessible using classical analytical techniques and thus complementing our current understanding of plant metal tolerance mechanisms as a whole.

Influence of aspect ratio and surface defect density on hydrothermally grown ZnO nanorods towards amperometric glucose biosensing applications

Science.gov (United States)

Shukla, Mayoorika; Pramila; Dixit, Tejendra; Prakash, Rajiv; Palani, I. A.; Singh, Vipul

2017-11-01

In this work, hydrothermally grown ZnO Nanorods Array (ZNA) has been synthesized over Platinum (Pt) coated glass substrate, for biosensing applications. In-situ addition of strong oxidizing agent viz KMnO4 during hydrothermal growth was found to have profound effect on the physical properties of ZNA. Glucose oxidase (GOx) was later immobilized over ZNA by means of physical adsorption process. Further influence of varying aspect ratio, enzyme loading and surface defects on amperometric glucose biosensor has been analyzed. Significant variation in biosensor performance was observed by varying the amount of KMnO4 addition during the growth. Moreover, investigations revealed that the suppression of surface defects and aspect ratio variation of the ZNA played key role towards the observed improvement in the biosensor performance, thereby significantly affecting the sensitivity and response time of the fabricated biosensor. Among different biosensors fabricated having varied aspect ratio and surface defect density of ZNA, the best electrode resulted into sensitivity and response time to be 18.7 mA cm-2 M-1 and <5 s respectively. The observed results revealed that apart from high aspect ratio nanostructures and the extent of enzyme loading, surface defect density also hold a key towards ZnO nanostructures based bio-sensing applications.

A preliminary study of the effect of phytoadditive carvacrol on the trace elements (Cu, Mn and Zn content in fish tissues

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EBRU YILMAZ

2014-04-01

Full Text Available Phytoadditives have gained increasing interest as feed additives for fish. The aim of the present study was to determine whether selected dietary phytoadditive can influence the bioavailability of several trace elements (Cu, Mn and Zn, which play an important role in the physiological processes. The experiments were carried out at a commercial trout farm. A total of 420 juvenile rainbow trout (mean weight ± SD = 10.79±0.57, Oncorhynchus mykiss, were randomly allocated into four different treatments with three replicates each. Fish were kept in raceways (3X0.8X0.4 m at 10±1°C with a natural photoperiod. Proper amount of carvacrol was sprayed on 1 kg of commercial trout diet to prepare four diets with 0 (Control, C0, 1 (C1, 3 (C3 and 5 (C5 carvacrol g/kg diet. Fish were fed to apparent satiation three times per day. The feeding trial lasted four weeks. Then, in different type of fish tissues (muscle, liver and pyloric caeca from fish fed with diets enriched in carvacrol, beneficial elements (Cu, Mn and Zn were analysed by atomic adsorption spectrophotometer. Results showed that the levels of Cu, Zn and Mn were especially significantly increase by C1 diet in all tissues (muscle, liver and pyloric caeca except muscle and pyloric caeca Zn. The results of this experiment indicate that the carvacrol had the ability to potentiate the trace element retention. Although bioaccumulations of Cu, Zn and Mn in the muscle, liver and pyloric caeca are well demonstrated, the exact mechanisms of phytoadditives are still only partially understood. More investigations are required to detail the mechanisms involved in phytoadditives this enhancement.

UV Enhanced Oxygen Response Resistance Ratio of ZnO Prepared by Thermally Oxidized Zn on Sapphire Substrate

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Cheng-Chang Yu

2013-01-01

Full Text Available ZnO thin film was fabricated by thermally oxidized Zn at 600°C for 1 h. A surface containing nanostructured dumbbell and lines was observed by scanning electron microscope (SEM. The ZnO resistor device was formed after the following Ti/Au metallization. The device resistance was characterized at different oxygen pressure environment in the dark and under ultraviolet (UV light illumination coming from the mercury lamp with a short pass filter. The resistance increases with the increase of oxygen pressure. The resistance decreases and response increases with the increase of light intensity. Models considering the barrier height variation caused by the adsorbed oxygen related species were used to explain these results. The UV light illumination technology shows an effective method to enhance the detection response for this ZnO resistor oxygen sensor.

Essential trace (Zn, Cu, Mn and toxic (Cd, Pb, Cr elements in the liver of birds from Eastern Poland

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Komosa A.

2012-01-01

Full Text Available We have focused our study on the concentrations of essential heavy metals (Zn, Cu and Mn and non-essential trace metals (Pb, Cd and Cr in the livers of birds from Eastern Poland. The largest mean amount of Zn - as much as 279 mg/kg dry mass (d.m. - was found in mute swans. However, only in one of the analysed buzzard specimens the concentration of Zn, found to be 664 mg/kg d.m., exceeded the level indicative of poisoning for this element. Birds specializing in catching rodents accumulated Mn in their livers in a very narrow range of concentrations, around 5.0 mg/kg d.m. on average. The range of mean Mn concentrations (around 6.5 mg/kg d.m. was also found to be narrow for piscivorous birds. The highest mean levels of Pb were found in mute swans (2.7 mg/kg d.m., and the highest levels of Cd (2.0 mg/kg d.m. for rooks. Concentrations of total Cr above detection level were found in 22 specimens (53.7%, and concentration values were highest for rooks. Analyses showed that the concentrations of biogenic elements did not exceed the levels indicative of poisoning (except in one specimen. The study demonstrated that lead shots remain a hazard to water ecosystems. Pb, Cd and Cr levels in the livers of omnivorous and piscivorous species indicate the permanent presence of these elements in the environment and may confirm the thesis about the growing role of electronic waste, including metallic e-waste, in the emission of the total amount of contamination with these elements.

PIXE analysis of trace elements in cetacean teeth

International Nuclear Information System (INIS)

Mitani, Yoko; Arai, Nobuaki; Sakamoto, Wataru; Yoshida, Koji

1997-01-01

PIXE was adopted for analysis of trace elements in teeth of two species of cetaceans, sperm whale (Physeter microcephalus) and pantropical spotted dolphin (Stenella attenuata). The analyses were performed along with the growth layer of the teeth, which is formed annually, suitable for age determination. Mn, Fe, Cu, Zu and Sr were detected in the teeth of sperm whale and pantropical spotted dolphin. Among these trace elements, gradual increase was observed for Zn/Ca ratio in the sperm whale's teeth. (author)

Assessment of the effects of glutamic acid decarboxylase antibodies and trace elements on cognitive performance in older adults

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Alghadir AH

2015-12-01

Full Text Available Ahmad H Alghadir,1 Sami A Gabr,1,2 Einas Al-Eisa11Department of Rehabilitation Sciences, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia; 2Department of Anatomy, Faculty of Medicine, Mansoura University, Mansoura, EgyptBackground: Homeostatic imbalance of trace elements such as iron (Fe, copper (Cu, and zinc (Zn demonstrated adverse effects on brain function among older adults.Objective: The present study aimed to investigate the effects of trace elements and the presence of anti-glutamic acid decarboxylase antibodies (GADAs in human cognitive abilities among healthy older adults.Methods: A total of 100 healthy subjects (65 males, 35 females; age range; 64–96 years were recruited for this study. Based on Loewenstein Occupational Therapy Cognitive Assessment (LOTCA score, the participants were classified according to cognitive performance into normal (n=45, moderate (n=30, and severe (n=25. Cognitive functioning, leisure-time physical activity (LTPA, serum trace elements – Fe, Cu, Zn, Zn/Cu, and GADAs were assessed using LOTCA battery, pre-validated physical activity (PA questionnaire, atomic absorption, and immunoassay techniques, respectively.Results: Approximately 45% of the study population (n=45 had normal distribution of cognitive function and 55% of the study population (n=55 had abnormal cognitive function; they were classified into moderate (score 62–92 and severe (score 31–62. There was a significant reduction in the level of Zn and Zn/Cu ratio along with an increase in the level of Fe, Cu, and anti-GADAs in subjects of severe (P=0.01 and moderate (P=0.01 cognitive performance. LOTCA-cognitive scores correlated positively with sex, HbA1c, Fe, Cu, Zn, and Zn/Cu ratio, and negatively with age, PA, body mass index, and anti-GADAs. Significant inter-correlation was reported between serum trace element concentrations and anti-GADAs which suggest producing a cognitive decline via oxidative and neural

Trace elements in digestive cancer tissue by PIXE

International Nuclear Information System (INIS)

Ciortea, C.; Constantinescu, O.; Cata, I.; Dumitriu, D. E.; Enulescu, A.; Fluerasu, D.; Pantelica, A.; Penescu, L. C.; Piticu, I.; Radu, A. T.; Vargolici, M.; Ciortea, M.; Staniceanu, F.; Popescu, E.; Donciu, D.; Moldovan, A.; Popescu, L.; Burghelea, B.

2004-01-01

Elemental composition study of digestive cancer tissue with different localizations (esophagus, stomach, colon) by using PIXE analysis is presented. A number of 20 tumor and normal (control) tissue samples were analyzed. Thin targets were prepared by mineralization of the lyophilized tissue with nitric acid and dropping on 2 μm Mylar foil. The measurements were carried out in vacuum using 3 MeV protons delivered by the tandem accelerator in Bucharest, Romania. The following elements were identified: S, Cl, K, Ca, Cr, Mn, Fe, Cu and Zn. Although the results show relatively large variations from a sample to another there were obtained mean ratios of tumor/normal concentrations which are significantly greater than one, in the limit of the standard deviation for the following elements: K (1.45±0.28), Ca (1.30±0.21), Cr (2.33±0.56), and Zn (1.18±0.15). For the other determined elements, no significant difference between the tumor and normal tissues, in the limit of the present standard deviation, was found. (authors)

Trace elements in digestive cancer tissue by PIXE

International Nuclear Information System (INIS)

Ciortea, Constantin; Constantinescu, Olimpiu; Filimon, Andrei

2005-01-01

Elemental composition study of digestive cancer tissue with different localizations (esophagus, stomach, colon), by using PIXE analysis, is presented. A number of 20 tumors and normal (control) tissue samples was analyzed. Thin targets were prepared by mineralization with nitric acid of the lyophilized tissue and dropping on 2 μm Mylar foil. The measurements were carried out in vacuum using 3 MeV protons delivered by the Tandem Accelerator in Bucharest, Romania. The following elements were determined: S, Cl, K, Ca, Cr, Mn, Fe, Cu and Zn. Although the results show relatively large variations from a sample to another, there were obtained mean ratios of tumor/normal concentrations which are significantly greater than one, in the limit of the standard deviation, for the following elements: K(1.45 ± 0.28), Ca(1.30 ± 0.21), Cr(2.33 ± 0.56), and Zn(1.18 ± 0.15). For other elements determined, no significant difference between the tumor and normal tissues , in the limit of the present standard deviation, was found. (authors)

Differential Scanning Calorimetry and Thermodynamic Predictions—A Comparative Study of Al-Zn-Mg-Cu Alloys

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Gernot K.-H. Kolb

2016-08-01

Full Text Available Al-Zn-Mg-Cu alloys are widely used in aircraft applications because of their superior mechanical properties and strength/weight ratios. Commercial Al-Zn-Mg-Cu alloys have been intensively studied over the last few decades. However, well-considered thermodynamic calculations, via the CALPHAD approach, on a variation of alloying elements can guide the fine-tuning of known alloy systems and the development of optimized heat treatments. In this study, a comparison was made of the solidus temperatures of different Al-Zn-Mg-Cu alloys determined from thermodynamic predictions and differential scanning calorimetry (DSC measurements. A variation of the main alloying elements Zn, Mg, and Cu generated 38 experimentally produced alloys. An experimental determination of the solidus temperature via DSC was carried out according to a user-defined method, because the broad melting interval present in Al-Zn-Mg-Cu alloys does not allow the use of the classical onset method for pure substances. The software algorithms implemented in FactSage®, Pandat™, and MatCalc with corresponding commercially available databases were deployed for thermodynamic predictions. Based on these investigations, the predictive power of the commercially available CALPHAD databases and software packages was critically reviewed.

Optimal Zn-Modified Ca–Si-Based Ceramic Nanocoating with Zn Ion Release for Osteoblast Promotion and Osteoclast Inhibition in Bone Tissue Engineering

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Jiangming Yu

2017-01-01

Full Text Available We investigated the slow release of Zn ion (Zn2+ from nanocoatings and compared the in vitro response of osteoblasts (MC3T3-E1 and proosteoclasts (RAW 264.7 cultured on Ca2ZnSi2O7 nanocoated with different Zn/Ca molar ratios on a Ti-6Al-4V (i.e., Ti substrate to optimize cell behaviors and molecule levels. Significant morphology differences were observed among samples. By comparing with pure Ti and CaSiO3 nanocoating, the morphology of Ca2ZnSi2O7 ceramic nanocoatings was rough and contained small nanoparticles or aggregations. Slow Zn2+ release from nanocoatings was observed and Zn2+ concentration was regulated by varying the Zn/Ca ratios. The cell-response results showed Ca2ZnSi2O7 nanocoating at different Zn/Ca molar ratios for osteoblasts and osteoclasts. Compared to other nanocoatings and Ti, sample Zn/Ca (0.3 showed the highest cell viability and upregulated expression of the osteogenic differentiation genes ALP, COL-1, and OCN. Additionally, sample Zn/Ca (0.3 showed the greatest inhibition of RAW 264.7 cell growth and decreased the mRNA levels of osteoclast-related genes OAR, TRAP, and HYA1. Therefore, the optimal Zn-Ca ratio of 0.3 in Ca2ZnSi2O7 ceramic nanocoating on Ti had a dual osteoblast-promoting and osteoclast-inhibiting effect to dynamically balance osteoblasts/osteoclasts. These optimal Zn-Ca ratios are valuable for Ca2ZnSi2O7 ceramic nanocoating on Ti-coated implants for potential applications in bone tissue regeneration.

Hardening mechanisms of spray formed Al-Zn-Mg-Cu alloys with scandium and other elemental additions

International Nuclear Information System (INIS)

Sharma, M.M.; Amateau, M.F.; Eden, T.J.

2006-01-01

The hardening mechanisms in spray formed Al-Zn-Mg-Cu alloys with additions of chromium, zinc and scandium were studied. The microstructure of the spray formed alloys was analyzed by transmission electron microscopy. A range of tensile strengths were achieved, and varied based on elemental additions, and second phase particle strengthening. To explain the significantly higher strength in one alloy with scandium, theoretical results due to the yield stress of Al-Zn-Mg-Cu alloys as a function of volume fraction and precipitate particle size, were compared to experimental data. Both the possibilities of coherency and order strengthening are examined. The significant additional hardening achieved in the alloy with scandium is attributed to small ordered particles of Al 3 Sc, which precipitated during aging

In-situ thermal analysis and macroscopical characterization of Mg–xCa and Mg–0.5Ca–xZn alloy systems

International Nuclear Information System (INIS)

Farahany, Saeed; Bakhsheshi-Rad, Hamid Reza; Idris, Mohd Hasbullah; Abdul Kadir, Mohammed Rafiq; Lotfabadi, Amir Fereidouni; Ourdjini, Ali

2012-01-01

Highlights: ► The effect of Ca and Zn addition on Mg–Ca and Mg–Ca–Zn were investigated. ► Ca and Zn addition decreased solid fraction at coherency point. ► T N –T DCP increased by adding Ca and Zn in Mg–Ca and Mg–Ca–Zn, respectively. ► Three reactions were detected when Zn/Ca atomic ratio less than 1.25 in Mg–Ca–Zn. ► A new peak Mg 51 Zn 20 was identified in Mg–0.5Ca–9Zn in addition of other peaks. - Abstract: This research described the identification phases by thermal analysis and microscopy inspection of Mg–xCa and Mg–0.5%Ca–xZn alloys that were solidified at slow cooling rate. Analysis of cooling curve after Ca addition shows the evolution of the Mg 2 Ca intermetallic phase at around 520 °C in addition to α-Mg phase. First derivative curves of alloys after the addition of Zn to Mg–0.5Ca alloy reveals three peaks related to α-Mg, Mg 2 Ca and Ca 2 Mg 6 Zn 3 for alloys that have Zn/Ca atomic ratio less than 1.23. The peak of Mg 2 Ca reaction on the first derivative curves disappeared for alloys containing Zn/Ca ratio more than 1.23. A new peak was also observed at 330 °C for Mg–0.5Ca–9Zn which was identified as Mg 51 Zn 20 . Solid fraction at coherency point decreased with increasing Ca and Zn elements. However, coherency time and difference between the nucleation and coherency temperatures (T N –T DCP ) increased by adding Ca and Zn in Mg–Ca and Mg–Ca–Zn systems.

Fabrication and properties of high-strength extruded brass using elemental mixture of Cu-40% Zn alloy powder and Mg particle

Energy Technology Data Exchange (ETDEWEB)

Atsumi, Haruhiko, E-mail: atsumi-h@jwri.osaka-u.ac.jp [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Imai, Hisashi; Li, Shufeng; Kondoh, Katsuyoshi [Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Kousaka, Yoshiharu; Kojima, Akimichi [San-etsu Metals Co. Ltd., 1892 Ohta, Tonami, Toyama 939-1315 (Japan)

2012-08-15

In this paper, high-strength brass (Cu-40% Zn) alloy with magnesium (Mg) element was fabricated via powder technology process, and the effect of the additive Mg element on microstructural and mechanical properties of extruded brass alloys with {alpha}-{beta} duplex phases was investigated. Pre-mixed Cu-40% Zn alloy powder with 0.5-1.5 mass% pure Mg powder (Cu-40% Zn + Mg) was consolidated using a spark plasma sintering (SPS) equipment. SPSed Cu-40% Zn + Mg specimens consisted of {alpha}-{beta} duplex phases containing Mg(Cu{sub 1-x}Zn{sub x}){sub 2} intermetallic compounds (IMCs) with a mean particle size of 10-30 {mu}m in diameter. The IMCs were completely dissolved in the {alpha}-{beta} duplex phases by a heat-treatment at 973 K for 15 min; thus, in order to disperse fine IMCs on {alpha}-{beta} duplex phase matrix, the SPSed Cu-40% Zn + Mg specimens were pre-heated at the solid solutionizing condition, and immediately extruded. The extruded specimen exhibited fine {alpha}-{beta} duplex phases, containing very fine precipitates of the above Mg(Cu{sub 1-x}Zn{sub x}){sub 2} IMCs with 0.5-3.0 {mu}m in diameter. In particular, a mean grain size of the extruded Cu-40% Zn + 1.0% Mg specimen was 3.32 {mu}m analyzed using an electron back-scattered diffraction. Tensile properties of the extruded Cu-40% Zn + 1.0% Mg specimen were an average value of yield strength (YS): 328 MPa, ultimate tensile strength (UTS): 553 MPa, and 25% elongation. This indicated that the extruded Cu-40% Zn + 1.0% Mg specimen revealed the significantly high-strength properties compared to a conventional binary brass alloy with 229 MPa YS and 464 MPa UTS. A high strengthening mechanism of this wrought brass alloy was mainly due to the grain refinement because of a pinning effect by the fine Mg(Cu{sub 1-x}Zn{sub x}){sub 2} precipitates at the boundaries of each phase. -- Highlights: Black-Right-Pointing-Pointer New high-strength extruded brass alloy with Mg was fabricated via powder metallurgy. Black

Synthesis of ZnFe2O4/ZnO nanocomposites immobilized on graphene with enhanced photocatalytic activity under solar light irradiation

International Nuclear Information System (INIS)

Sun, Lin; Shao, Rong; Tang, Lanqin; Chen, Zhidong

2013-01-01

Highlights: ► ZnFe 2 O 4 /ZnO nanocomposites immobilized on graphene were successfully prepared. ► The photocatalyst exhibited excellent reactivity under solar light irradiation. ► The photocatalysts could be recycled by external magnetic field conveniently. ► The photocatalytic mechanism of the novel material was proposed in detail. -- Abstract: Magnetically recyclable ZnFe 2 O 4 /ZnO nanocomposites immobilized on different content of graphene with favorable photocatalytic activity under solar light irradiation were successfully prepared on the basis of an ultrasound aided solution method. The molar ratio of ZnFe 2 O 4 to ZnO and the content of graphene could be controlled by adjusting the amount of zinc salts and graphene oxide dispersions. The most excellent photocatalytic activity under solar light irradiation was displayed when the molar ratio of ZnFe 2 O 4 to ZnO was 0.1 and the weight ratio of graphene to ZnFe 2 O 4 /ZnO was 0.04. Furthermore, the presence of magnetical ZnFe 2 O 4 will facilitate the recycling process of photocatalyst nanoparticles

Determination of Cu/Zn and Fe in human serum of patients with sickle cell anemia using radiation synchrotron

Energy Technology Data Exchange (ETDEWEB)

Canellas, C.G.L. [Nuclear Instrumentation Laboratory, COPPE/UFRJ, P.O. Box 68509, 21.941-972 Rio de Janeiro (Brazil); Carvalho, S.M.F. [State Institute of Hematology Arthur de Siqueira Cavalcanti, 20.211-030 Rio de Janeiro (Brazil); Anjos, M.J. [Nuclear Instrumentation Laboratory, COPPE/UFRJ, P.O. Box 68509, 21.941-972 Rio de Janeiro (Brazil); Physics Institute, State University of Rio de Janeiro, 20.559-900 Rio de Janeiro (Brazil); Lopes, R.T., E-mail: ricardo@lin.ufrj.br [Nuclear Instrumentation Laboratory, COPPE/UFRJ, P.O. Box 68509, 21.941-972 Rio de Janeiro (Brazil)

2012-07-15

In this work we analyzed serum samples from patients with Sickle Cell Anemia (SCA) using Total Reflection X-Ray Fluorescence using Synchrotron Radiation (SRTXRF). The SRTXRF measurements were performed at the X-Ray Fluorescence Beamline at the Brazilian National Synchrotron Light Laboratory (LNLS). We studied forty-three patients aged 18-50 suffering from SCA and sixty healthy volunteers aged 18-60. It was possible to determine the concentrations of the following elements: P, S, Cl, K, Ca, Fe, Cu, Zn, Br and Rb. Moreover, there are evidences of an association among Fe, Cu, Zn and Cu/Zn in the SCA pathogenesis process. The concentrations of Fe and Cu in the serum samples of patients with SCA were larger, 120% and 20%, respectively, when compared with the CG. The serum level Cu/Zn ratio was significantly higher (60%) in the serum samples from patients suffering from SCA than from the CG. Therefore, the Cu/Zn ratio can be used as an adjuvant index in enhancement for diagnosis of SCA. - Highlights: Black-Right-Pointing-Pointer Serum samples from patients with Sickle Cell Anemia (SCA) were analyzed by SRTXRF. Black-Right-Pointing-Pointer It was possible to determine the concentrations of the P, S, Cl, K, Ca, Fe, Cu, Zn, Br and Rb. Black-Right-Pointing-Pointer There are evidences of an association among Fe, Cu, Zn and Cu/Zn in the SCA process. Black-Right-Pointing-Pointer The results indicate that the Cu/Zn ratio can be used as an adjuvant index for diagnosis of SCA.

Determination of Cu/Zn and Fe in human serum of patients with sickle cell anemia using radiation synchrotron

International Nuclear Information System (INIS)

Canellas, C.G.L.; Carvalho, S.M.F.; Anjos, M.J.; Lopes, R.T.

2012-01-01

In this work we analyzed serum samples from patients with Sickle Cell Anemia (SCA) using Total Reflection X-Ray Fluorescence using Synchrotron Radiation (SRTXRF). The SRTXRF measurements were performed at the X-Ray Fluorescence Beamline at the Brazilian National Synchrotron Light Laboratory (LNLS). We studied forty-three patients aged 18–50 suffering from SCA and sixty healthy volunteers aged 18–60. It was possible to determine the concentrations of the following elements: P, S, Cl, K, Ca, Fe, Cu, Zn, Br and Rb. Moreover, there are evidences of an association among Fe, Cu, Zn and Cu/Zn in the SCA pathogenesis process. The concentrations of Fe and Cu in the serum samples of patients with SCA were larger, 120% and 20%, respectively, when compared with the CG. The serum level Cu/Zn ratio was significantly higher (60%) in the serum samples from patients suffering from SCA than from the CG. Therefore, the Cu/Zn ratio can be used as an adjuvant index in enhancement for diagnosis of SCA. - Highlights: ► Serum samples from patients with Sickle Cell Anemia (SCA) were analyzed by SRTXRF. ► It was possible to determine the concentrations of the P, S, Cl, K, Ca, Fe, Cu, Zn, Br and Rb. ► There are evidences of an association among Fe, Cu, Zn and Cu/Zn in the SCA process. ► The results indicate that the Cu/Zn ratio can be used as an adjuvant index for diagnosis of SCA.

Influence of zinc on the biokinetics of Zn-65 and hepatic trace elements of ethanol treated rats

International Nuclear Information System (INIS)

Dhawan, D.K.; Pathak, A.; Pathak, R.; Mahmood, A.

2002-01-01

Influence of zinc on the biokinetics of 65 Zn and hepatic trace elements of ethanol treated rats. The effect of zinc on the biokinetics of 65 Zn in liver and whole body and its relation to the hepatic levels of different elements was evaluated in male wistar rats under alcoholic conditions. The rats were segregated into four treatment groups viz., normal control, ethanol treated, zinc treated and combined zinc+ethanol treated. Animals were fed 3ml of 30% ethanol orally daily and zinc in the form of zinc sulfate (ZnSo 4 7H 2 O) was administrated to rats at a dose level of 227mg/L mixed in their drinking water for a total duration of 2 months. Whole body counting studies indicated that the Tb 1 i.e., the faster elimination of the radiotracer. On the contrary, Tb 2 i.e., the slower component was increased significantly following ethanol treatment. Percent uptake values of 65 Zn were found to be increased in liver, intestine, muscle and kidney and decreased in bone under alcoholic conditions. A significant elevation was noticed in in vitro uptake 65 Zn in ethanol treated animals. In the above said conditions, the values were reverted back to within normal limits upon zinc supplementation to these ethanol intoxicated animals, except in the case of in vitro 65 Zn uptake in liver where the uptake was further increased upon combined treatment. A significant decrease in zinc contents was noticed in ethanol treated rats, which however were raised to normal levels upon zinc supplementation. Copper levels, on the other hand, were found to be significantly enhanced in both ethanol fed and combined ethanol+zinc supplemented animals. Calcium levels were found to e significantly decreased in both ethanol and zinc treated rats, which however were further reduced upon zinc supplementation to ethanol fed rats. However, no significant change was observed in the concentrations of sodium and potassium in any of the treatment groups. Therefore, zinc appears to play a protective role by

Effects of KOH:ZnCl{sub 2} mole ratio on the phase formation, morphological and inhibitive properties of potassium zinc phosphate (PZP) pigments

Energy Technology Data Exchange (ETDEWEB)

Askari, F. [Inorganic Pigment and Glazes Department, Institute for Color Science and Technology, Tehran 1668814811 (Iran, Islamic Republic of); Surface Coatings and Corrosion Department, Institute for Color Science and Technology, Tehran 1668814811 (Iran, Islamic Republic of); Ghasemi, E., E-mail: eghasemi@iust.ac.ir [Inorganic Pigment and Glazes Department, Institute for Color Science and Technology, Tehran 1668814811 (Iran, Islamic Republic of); Ramezanzadeh, B.; Mahdavian, M. [Surface Coatings and Corrosion Department, Institute for Color Science and Technology, Tehran 1668814811 (Iran, Islamic Republic of)

2015-05-15

Graphical abstract: This figure illustrates the inhibition mechanism. The film precipitation on the anodic and cathodic regions of the metal surface causes a drop in dissolution rate of steel. - Highlights: • We synthesized the ZP pigments via coprecipitation method. • Effect of KOH:ZnCl{sub 2} on phase formation, morphology and inhibitive performance of pigment. • KOH:ZnCl{sub 2} ratio is effective on phase formation and morphology of ZP pigments. • KZn{sub 2}H(PO{sub 4}){sub 2} phase showed superior corrosion inhibition behavior than KZnPO{sub 4}. - Abstract: Different types of potassium zinc phosphate (PZP) pigments were synthesized by a co-precipitation method. The PZPs were obtained through changing KOH:ZnCl{sub 2} mole ratio. The chemical composition of the pigments was studied by X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy (SEM). Then, the extracts of the PZPs were prepared in 3.5% (w/w) NaCl solution. The inhibitive performance of the pigments was investigated by polarization technique and SEM surface analysis through dipping mild steel panels in the pigment extracts for different immersion times. Results showed that changing ZnCl{sub 2}/KOH mole ratio could influence formation of KZn{sub 2}H(PO{sub 4}){sub 2} and KZnPO{sub 4} phases. It was known that the KZn{sub 2}H(PO{sub 4}){sub 2} phase has a superior corrosion inhibition behavior in 3.5% NaCl solution than KZnPO{sub 4} phase.

Complexity and Productivity Differentiation Models of Metallogenic Indicator Elements in Rocks and Supergene Media Around Daijiazhuang Pb–Zn Deposit in Dangchang County, Gansu Province

International Nuclear Information System (INIS)

He, Jin-zhong; Yao, Shu-zhen; Zhang, Zhong-ping; You, Guan-jin

2013-01-01

With the help of complexity indices, we quantitatively studied multifractals, frequency distributions, and linear and nonlinear characteristics of geochemical data for exploration of the Daijiazhuang Pb–Zn deposit. Furthermore, we derived productivity differentiation models of elements from thermodynamics and self-organized criticality of metallogenic systems. With respect to frequency distributions and multifractals, only Zn in rocks and most elements except Sb in secondary media, which had been derived mainly from weathering and alluviation, exhibit nonlinear distributions. The relations of productivity to concentrations of metallogenic elements and paragenic elements in rocks and those of elements strongly leached in secondary media can be seen as linear addition of exponential functions with a characteristic weak chaos. The relations of associated elements such as Mo, Sb, and Hg in rocks and other elements in secondary media can be expressed as an exponential function, and the relations of one-phase self-organized geological or metallogenic processes can be represented by a power function, each representing secondary chaos or strong chaos. For secondary media, exploration data of most elements should be processed using nonlinear mathematical methods or should be transformed to linear distributions before processing using linear mathematical methods.

Adsorption of tetracycline on Fe (hydr)oxides: effects of pH and metal cation (Cu2+, Zn2+ and Al3+) addition in various molar ratios

Science.gov (United States)

Hsu, Liang-Ching; Liu, Yu-Ting; Syu, Chien-Hui; Huang, Mei-Hsia; Teah, Heng Yi

2018-01-01

Iron (Fe) (hydr)oxides control the mobility and bioavailability of tetracycline (TC) in waters and soils. Adsorption of TC on Fe (hydr)oxides is greatly affected by polyvalent metals; however, impacts of molar metal/TC ratios on TC adsorptive behaviours on Fe (hydr)oxides remain unclear. Results showed that maximum TC adsorption on ferrihydrite and goethite occurred at pH 5–6. Such TC adsorption was generally promoted by the addition of Cu2+, Zn2+ and Al3+. The greatest increase in TC adsorption was found in the system with molar Cu/TC ratio of 3 due to the formation of Fe hydr(oxide)–Cu–TC ternary complexes. Functional groups on TC that were responsible for the complexation with Cu2+shifted from phenolic diketone groups at Cu/TC molar ratio adsorption at a molar Al/TC ratio of 1. However, TC adsorption decreased for Al/TC molar ratio > 1 as excess Al3+ led to the competitive adsorption with Al/TC complexes. For the Zn2+ addition, no significant correlation was found between TC adsorption capacity and molar Zn/TC ratios. PMID:29657795

The relationship of element contents in erythrocyte with thyroid function

International Nuclear Information System (INIS)

Zhu Li; Zhao Zhiying; Wang Zhenghua; Li Yanfen; Liu Nianqing; Liu Pingsheng; Xu qing; Liu Peng; Qian Qingfang

1998-01-01

The serum thyroid hormones (T 3 , T 4 , TSH, FT 3 and FT 4 ) level and the elements K, Ca, Fe, Cu, Zn, Se and Rb in the erythrocyte in 76 cases is measured by radiometric assay in vitro (RIA and IRMA) and nuclear analytical technique (PIXE and INNA). According to thyroid hormones level, the cases are divided into four groups with hyperthyroid, normal, subhyperthyroid and hypothyroid. The difference and correlation of various parameters in four groups are compared by Oneway-ANOVA and Partial Correlation using SPSS/PC statistical package respectively. The results show that the content of Zn for hypothyroid group is significantly higher than hyperthyroid (P = 0.007) and sub-hyperthyroid (P = 0.046) groups, and the content of Zn for normal is lower than hypothyroid group but not significant difference (P = 0.083), the other elements contents are no significant difference among four groups. The highly significant linear correlation between the contents of K, Zn and Cu in the erythrocyte and T 3 , T 4 level ratio and TSH level is observed in hypothyroid and normal groups, the close correlation between the content of Se and serum T 4 and TSH level is also observed in hyperthyroid and sub-hyperthyroid groups. These suggest that trace elements may be important for the synthesis, metabolism and biological function of thyroid hormones

Characteristics of plant concentration ratios assessed in a 64-site field survey of 23 elements

International Nuclear Information System (INIS)

Sheppard, S.C.; Evenden, W.G.

1990-01-01

Many of the statistical characteristics of plant concentration ratios (CRs) and translocation factors (TFs) have not been critically assessed, especially in field surveys. The statistical characteristics, particularly the measures of variation, are important for stochastic modelling of plant uptake. The CR and TF values for 23 naturally occurring elements throughout the geographic range of one plant species, blueberries (Vaccinium angustifolium), in Canada were surveyed. Although the ratios imply linear relationships, the numerator concentrations were not closely correlated with the denominator concentrations. The variation in the ratios was not clearly related to the means or to characteristics of the elements. The overall geometric standard deviation for CRs was 2.5 and for TFs was 1.6. The values of CR were intercorrelated for certain groups of elements and these groups reflected the periodic classification of elements. Thus, correlation between elements in stochastic models, which may reduce overall variability, is valid. Site variables such as soil pH, soil bulk density, soil fertility and plant growth condition were only slightly useful in statistically explaining some of the variation in CR values. (author)

Synthesis of highly luminescent Mn:ZnSe/ZnS nanocrystals in aqueous media

International Nuclear Information System (INIS)

Fang Zheng; Wu Ping; Zhong Xinhua; Yang Yongji

2010-01-01

High-quality water-dispersible Mn 2+ -doped ZnSe core/ZnS shell (Mn:ZnSe/ZnS) nanocrystals have been synthesized directly in aqueous media. Overcoating a high bandgap ZnS shell around the Mn:ZnSe cores can bring forward an efficient energy transfer from the ZnSe host nanocrystals to the dopant Mn. The quantum yields of the dopant Mn photoluminescence in the as-prepared water-soluble Mn:ZnSe/ZnS core/shell nanocrystals can be up to 35 ± 5%. The optical features and structure of the obtained Mn:ZnSe/ZnS core/shell nanocrystals have been characterized by UV-vis, PL spectroscopy, TEM, XRD and ICP elementary analysis. The influences of various experimental variables, including the Mn concentration, the Se/Zn molar ratio as well as the kind and amount of capping ligand used in the core production and shell deposition process, on the luminescent properties of the obtained Mn:ZnSe/ZnS nanocrystals have been systematically investigated.

Growth stimulation of Bacillus cereus and Pseudomonas putida using nanostructured ZnO thin film as transducer element

International Nuclear Information System (INIS)

Loukanov, Alexandre; Filipov, Chavdar; Valcheva, Violeta; Lecheva, Marta; Emin, Saim

2015-01-01

The semiconductor zinc oxide nanomaterial (ZnO or ZnO:H) is widely used in advanced biosensor technology for the design of highly-sensitive detector elements for various applications. In the attempt to evaluate its effect on common microorganisms, two types of nanostructured transducer films have been used (average diameter 600–1000 nm). They have been prepared by using both wet sol–gel method and magnetron sputtering. Their polycrystalline structure and specific surface features have been analyzed by X-ray diffraction (XRD), scanning electron microscope, and atomic force microscope. The assessment of growth stimulation of bacteria was determined using epifluorescent microscope by cell staining with Live/Dead BacLight kit. In our experiments, the growth stimulation of Gram-positive and Gram-negative bacteria on nanostructured ZnO film is demonstrated by Bacillus cereus and Pseudomonas putida. These two bacterial species have been selected, because they are well known and studied in biosensor technologies, with structural difference of their cell walls. These pathogens are easy for with common source in the liquid food or some commercial products. Our data has revealed that the method of transducer film preparation influences strongly bacterial inhibition and division. These results present the transforming signal precisely, when ZnO is used in biosensor applications

Growth stimulation of Bacillus cereus and Pseudomonas putida using nanostructured ZnO thin film as transducer element

Science.gov (United States)

Loukanov, Alexandre; Filipov, Chavdar; Valcheva, Violeta; Lecheva, Marta; Emin, Saim

2015-04-01

The semiconductor zinc oxide nanomaterial (ZnO or ZnO:H) is widely used in advanced biosensor technology for the design of highly-sensitive detector elements for various applications. In the attempt to evaluate its effect on common microorganisms, two types of nanostructured transducer films have been used (average diameter 600-1000 nm). They have been prepared by using both wet sol-gel method and magnetron sputtering. Their polycrystalline structure and specific surface features have been analyzed by X-ray diffraction (XRD), scanning electron microscope, and atomic force microscope. The assessment of growth stimulation of bacteria was determined using epifluorescent microscope by cell staining with Live/Dead BacLight kit. In our experiments, the growth stimulation of Gram-positive and Gram-negative bacteria on nanostructured ZnO film is demonstrated by Bacillus cereus and Pseudomonas putida. These two bacterial species have been selected, because they are well known and studied in biosensor technologies, with structural difference of their cell walls. These pathogens are easy for with common source in the liquid food or some commercial products. Our data has revealed that the method of transducer film preparation influences strongly bacterial inhibition and division. These results present the transforming signal precisely, when ZnO is used in biosensor applications.

Growth stimulation of Bacillus cereus and Pseudomonas putida using nanostructured ZnO thin film as transducer element

Energy Technology Data Exchange (ETDEWEB)

Loukanov, Alexandre, E-mail: loukanov@mail.saitama-u.ac.jp [Saitama University, Department of Chemistry, Faculty of Science (Japan); Filipov, Chavdar [University of Forestry, Department of Infectious pathology, hygiene, technology and control of food stuffs of animal origin, Faculty of Veterinary Medicine (Bulgaria); Valcheva, Violeta [Bulgarian Academy of Science, Department of Infectious Diseases, Institute of microbiology (Bulgaria); Lecheva, Marta [University of Mining and Geology “St. Ivan Rilski”, Laboratory of Engineering NanoBiotechnology, Department of Engineering Geoecology (Bulgaria); Emin, Saim [University of Nova Gorica, Materials Research Laboratory (Slovenia)

2015-04-15

The semiconductor zinc oxide nanomaterial (ZnO or ZnO:H) is widely used in advanced biosensor technology for the design of highly-sensitive detector elements for various applications. In the attempt to evaluate its effect on common microorganisms, two types of nanostructured transducer films have been used (average diameter 600–1000 nm). They have been prepared by using both wet sol–gel method and magnetron sputtering. Their polycrystalline structure and specific surface features have been analyzed by X-ray diffraction (XRD), scanning electron microscope, and atomic force microscope. The assessment of growth stimulation of bacteria was determined using epifluorescent microscope by cell staining with Live/Dead BacLight kit. In our experiments, the growth stimulation of Gram-positive and Gram-negative bacteria on nanostructured ZnO film is demonstrated by Bacillus cereus and Pseudomonas putida. These two bacterial species have been selected, because they are well known and studied in biosensor technologies, with structural difference of their cell walls. These pathogens are easy for with common source in the liquid food or some commercial products. Our data has revealed that the method of transducer film preparation influences strongly bacterial inhibition and division. These results present the transforming signal precisely, when ZnO is used in biosensor applications.

Low-temperature solid-state synthesis and optical properties of CdS-ZnS and ZnS-CdS alloy nanoparticles

International Nuclear Information System (INIS)

Liu Jinsong; Zhao Chuanbao; Li Ziquan; Chen Jiankang; Zhou Hengzhi; Gu Shanqun; Zeng Youhong; Li Yongchan; Huang Yongbing

2011-01-01

Highlights: → Using a simple low-temperature solid-state synthetic method, ZnS-CdS and CdS-ZnS alloy nanoparticles were obtained, respectively. → The size of the nanoparticles increased with increasing reaction temperature, and reaction sequence had no effect on the size of the nanoparticles under the same temperature. → The particle diameters of the CdS-ZnS products decreased gradually with increasing Cd 2+ /Zn 2+ molar ratio, whereas those of the ZnS-CdS products increased gradually with increasing Zn 2+ /Cd 2+ molar ratio. → The study shows that sufficient grinding and crystalline water may be a key in forming the alloy nanoparticles. → Optical properties of the products depend on reaction temperature, reactant addition sequence, and reactant molar ratio. - Abstract: A simple low-temperature solid-state synthetic method was employed to obtain ZnS-CdS and CdS-ZnS alloy nanoparticles. The effects of reaction sequence, reactant molar ratios, and synthesis temperature on the products were investigated. The crystal structure and morphology of the products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and fourier transform infrared (FT-IR) spectroscopy. The results show that the products are alloy nanoparticles with a cubic phase structure. The formation mechanism of the alloy nanoparticles is briefly discussed. Sufficient grinding and crystalline water may be essential to form alloy nanoparticles. Ultraviolet-visible (UV-vis) spectra show that the edge absorptions of the CdS-ZnS and ZnS-CdS nanoparticles were located between those of ZnS and CdS bulks, and the absorbance at the peak maximum was practically dependent on reaction temperature, reaction sequence, and molar ratio. Extrinsic deep-level emission resulted in strong peaks in the photoluminescence (PL) spectra. The position and intensity of the emission peaks varied with the conditions during synthesis.

Determination of elements in ayurvedic medicinal plants by AAS

International Nuclear Information System (INIS)

Teerthe, Santoshkumar S.; Kerur, B. R.

2015-01-01

India has a rich country for the uses of Ayurvedic medicinal plants for treatment and also the north- Karnataka boasts an unparallel diversity of medicinal plants. The present study attempts to estimate and compare the level of trace and heavy metals in some selected leaves and root samples of Ayurvedic medicinal plants such as Mg, Al, K, Cr, Mn, Fe, Cu, Zn, and Cd. The samples are collected from different places of North-Karnataka regions and sample solutions prepared as the ratio of 1:25:25+950ml=1000ppm.the trace and heavy elemental concentration was estimated using Atomic Absorption Spectrometric (AAS) Method. The average concentrations of Mg, Mn, Fe and Zn, are ranging from 2ppm to 5250.2ppm and potassium (K) has more concentration as compare to all other. The other elements likes Al, Cr, Cu, and Cd were also estimed and presented in the table. Therefore, these medicinal plants are rich in some essential minerals, especially K, Mg, Mn, Fe and Zn which are essential for human health

Determination of elements in ayurvedic medicinal plants by AAS

Energy Technology Data Exchange (ETDEWEB)

Teerthe, Santoshkumar S.; Kerur, B. R., E-mail: kerurbrk@yahoo.com [Department of Physics, Gulbarga University, Gulbarga, and Karnataka, India – 585106 (India)

2015-08-28

India has a rich country for the uses of Ayurvedic medicinal plants for treatment and also the north- Karnataka boasts an unparallel diversity of medicinal plants. The present study attempts to estimate and compare the level of trace and heavy metals in some selected leaves and root samples of Ayurvedic medicinal plants such as Mg, Al, K, Cr, Mn, Fe, Cu, Zn, and Cd. The samples are collected from different places of North-Karnataka regions and sample solutions prepared as the ratio of 1:25:25+950ml=1000ppm.the trace and heavy elemental concentration was estimated using Atomic Absorption Spectrometric (AAS) Method. The average concentrations of Mg, Mn, Fe and Zn, are ranging from 2ppm to 5250.2ppm and potassium (K) has more concentration as compare to all other. The other elements likes Al, Cr, Cu, and Cd were also estimed and presented in the table. Therefore, these medicinal plants are rich in some essential minerals, especially K, Mg, Mn, Fe and Zn which are essential for human health.

Effect of Zn(NO{sub 3}){sub 2} concentration in hydrothermal–electrochemical deposition on morphology and photoelectrochemical properties of ZnO nanorods

Energy Technology Data Exchange (ETDEWEB)

Yilmaz, Ceren, E-mail: ceryilmaz@ku.edu.tr [Koc University, Department of Chemistry, Rumelifeneri yolu, Sariyer 34450, Istanbul (Turkey); Unal, Ugur [Koc University, Department of Chemistry, Rumelifeneri yolu, Sariyer 34450, Istanbul (Turkey); Graduate School of Science and Engineering, Koc University, Rumelifeneri yolu, Sariyer 34450, Istanbul (Turkey); Koc University Surface Science and Technology Center (KUYTAM), Rumelifeneri yolu, Sariyer 34450, Istanbul (Turkey)

2016-04-15

Graphical abstract: - Highlights: • Combined hydrothermal–electrochemical deposition was used to grow ZnO films. • 1-D ZnO NRs are obtained even at high Zn(NO{sub 3}){sub 2} concentrations (1 mM < [Zn{sup 2+}] < 0.1 M). • Aspect ratio and alignment of ZnO NRs can be controlled by initial [Zn(NO{sub 3}){sub 2}]. • [Zn{sup 2+}] dependent structural and photoelectrochemical properties have been studied. • Photocurrent density exhibited by ZnO NRs increases with increasing aspect ratio. - Abstract: Zn(NO{sub 3}){sub 2} concentration had been reported to be significantly influential on electrodeposition of ZnO structures. In this work, this issue is revisited using hydrothermal–electrochemical deposition (HED). Seedless, cathodic electrochemical deposition of ZnO films is carried out on ITO electrode at 130 °C in a closed glass reactor with varying Zn(NO{sub 3}){sub 2} concentration. Regardless of the concentration of Zn{sup 2+} precursor (0.001–0.1 M) in the deposition solution, vertically aligned 1-D ZnO nanorods are obtained as opposed to electrodepositions at lower temperatures (70–80 °C). We also report the effects of high bath temperature and pressure on the photoelectrochemical properties of the ZnO films. Manipulation of precursor concentration in the deposition solution allows adjustment of the aspect ratio of the nanorods and the degree of texturation along the c-axis; hence photoinduced current density. HED is shown to provide a single step synthesis route to prepare ZnO rods with desired aspect ratio specific for the desired application just by controlling the precursor concentration.

Investigation of the nanoscale two-component ZnS-ZnO heterostructures by means of HR-TEM and X-ray based analysis

Science.gov (United States)

Pankin, I. A.; Polozhentsev, O. E.; Soldatov, M. A.; Bugaev, A. L.; Tsaturyan, A.; Lomachenko, K. A.; Guda, A. A.; Budnyk, A. P.; Lamberti, C.; Soldatov, A. V.

2018-06-01

This article is devoted to the spectroscopic characterization of ZnS-ZnO nanoscale heterostructures synthesized by the microwave-assisted solvothermal method. The synthesized samples were investigated by means of X-ray powder diffraction (XRPD), high energy resolution fluorescence detected X-ray absorption near-edge-structure (HERFD-XANES) spectroscopy, valence-to-core X-ray emission spectroscopy (VtC-XES) and high resolution transmission electron microscopy (HR-TEM) as well as energy dispersive X-ray spectroscopy (EDX). The average crystallite size estimated by the broadening of XRPD peaks increases from 2.7 nm to 3.7 nm in the temperature range from 100 °C to 150 °C. HR-TEM images show that nanoparticles are arranged in aggregates with the 60-200 nm size. Theoretical estimation shows that the systems synthesized at higher temperatures more prone to the agglomeration. The full profile Reitveld analysis of XRPD data reveals the formation of hexagonal zinc sulfide structure, whereas electron diffraction data reveal also the formation of cubic zinc sulfide and claim the polymorphous character of the system. High energy resolution Zn K-edge XANES data unambiguously demonstrate the presence of a certain amount of the zinc oxide which is likely to have an amorphous structure and could not be detected by XRPD. Qualitative analysis of XANES data allows deriving ZnS/ZnO ratio as a function of synthesis temperature. EDX analysis depicts homogeneous distribution of ZnS and amorphous ZnO phases across the conglomerates. A complementary element-selective valence to core X-ray emission spectroscopy evidences formation of two-component system and confirms estimations of ZnS/ZnO fractions obtained by linear combination fit of XANES data.

Photoluminescence and electrochemical properties of transparent CeO{sub 2}-ZnO nanocomposite thin films prepared by Pechini method

Energy Technology Data Exchange (ETDEWEB)

Sani, Z.K.; Ghodsi, F.E.; Mazloom, J. [University of Guilan, Department of Physics, Faculty of Science, Namjoo Ave, P.O. Box 41335-1914, Rasht (Iran, Islamic Republic of)

2017-02-15

Nanocomposite thin films of CeO{sub 2}-ZnO with different molar ratios of Zn/Ce (=0, 0.25, 0.5, 0.75 and 1) were prepared by the Pechini sol-gel route. Various spectroscopic and electrochemical techniques were applied to investigate the films. XRD patterns of all the samples exhibited the peaks corresponding to cubic fluorite structure of ceria and the (101) and (103) peaks of ZnO with hexagonal structure was just observed in the sample with molar ratio of 1. EDS confirmed the presence of constituent of element in the samples. FESEM images of the films showed a surface composed of nanograins. AFM analysis revealed that root mean square roughness was enhanced as molar ratio of Zn/Ce increased. Moreover, fractal dimension of surfaces were calculated by cube counting approach. Optical measurements indicated that the film with molar ratio of 1 has the highest transmission and lowest reflectivity. The optical band gap values varied between 2.95 and 3.42 eV. The compositional dependence of refractive index and extinction coefficient were reported. The UV and blue emission appeared in PL spectra. The highest photoluminescence emission intensity was observed in the 1:1 molar ratio sample. The cyclic voltammetry measurements indicated the highest charge density (9.75 mC cm{sup -2}) and diffusion coefficient (3.507 x 10{sup -17} cm{sup 2} s{sup -1}) belonged to the Ce/Zn (1:1) thin film. (orig.)

The behaviour of the elements Ni, Co, Cu, Pb, Zn, Au, Ag, Mo, Sn, W and U in the magmatic, hydrothermal, sedimentary and weathering environments

International Nuclear Information System (INIS)

Anderson, J.R.

1978-01-01

In the last two decades much has been published on the behaviour of certain elements in the magmatic, hydrothermal, sedimentary and weathering environments, but the information is scattered throughout the literature. This situation prompted the present study on the elements Ni, Co, Cu, Pb, Zn, Au, Ag, Mo, Sn, W and U. The behaviour of the elements Ni, Cu, Pb, Zn, Au, Sn, W and U has been studied experimentally in some depth. Ag has been moderately studied, but there is very little information about Co and Mo. Studies on the complexes formed by the elements within the hydrothermal and aqueous environment are often inconclusive and controversial, but conclusions are drawn as to the more likely complexes formed. A genetic classification of ore deposits is used as a framework for the discussion. The source of the elements is regarded as being the mantle, and therefore discussion on other possible sources is beyond the scope of this dissertation. The crystal chemistry and geochemistry of the elements are presented and the essay concludes with a discussion on the elements within their depositional environments

Exposure of Arabidopsis thaliana to excess Zn reveals a Zn-specific oxidative stress signature.

NARCIS (Netherlands)

Remans, T.; Opdenakker, G.; Guisez, Y.; Carleer, R.; Schat, H.; Vangronsveld, J.; Cuypers, A.

2012-01-01

Zinc (Zn) is an essential micronutrient for plants, but accumulation of excess Zn causes oxidative stress, even though the element is not redox-active. An oxidative stress signature, consisting of multiple oxidative stress related parameters, is indicative of disturbance of redox homeostasis and

Thermodynamic modeling of the Ce-Zn and Pr-Zn systems

International Nuclear Information System (INIS)

Wang, C.P.; Chen, X.; Liu, X.J.; Pan, F.S.; Ishida, K.

2008-01-01

In order to develop the thermodynamic database of phase equilibria in the Mg-Zn-Re (Re: rare earth element) base alloys, the thermodynamic assessments of the Ce-Zn and Pr-Zn systems were carried out by using the calculation of phase diagrams (CALPHAD) method on the basis of the experimental data including thermodynamic properties and phase equilibria. Based on the available experimental data, Gibbs free energies of the solution phases (liquid, bcc, fcc, hcp and dhcp) were modeled by the subregular solution model with the Redlich-Kister formula, and those of the intermetallic compounds were described by the sublattice model. A consistent set of thermodynamic parameters has been derived for describing the Gibbs free energies of each solution phase and intermetallic compound in the Ce-Zn and Pr-Zn binary systems. An agreement between the present calculated results and experimental data is obtained

The association between content of the elements S, Cl, K, Fe, Cu, Zn and Br in normal and cirrhotic liver tissue from Danes and Greenlandic Inuit examined by dual hierarchical clustering analysis.

Science.gov (United States)

Laursen, Jens; Milman, Nils; Pind, Niels; Pedersen, Henrik; Mulvad, Gert

2014-01-01

Meta-analysis of previous studies evaluating associations between content of elements sulphur (S), chlorine (Cl), potassium (K), iron (Fe), copper (Cu), zinc (Zn) and bromine (Br) in normal and cirrhotic autopsy liver tissue samples. Normal liver samples from 45 Greenlandic Inuit, median age 60 years and from 71 Danes, median age 61 years. Cirrhotic liver samples from 27 Danes, median age 71 years. Element content was measured using X-ray fluorescence spectrometry. Dual hierarchical clustering analysis, creating a dual dendrogram, one clustering element contents according to calculated similarities, one clustering elements according to correlation coefficients between the element contents, both using Euclidian distance and Ward Procedure. One dendrogram separated subjects in 7 clusters showing no differences in ethnicity, gender or age. The analysis discriminated between elements in normal and cirrhotic livers. The other dendrogram clustered elements in four clusters: sulphur and chlorine; copper and bromine; potassium and zinc; iron. There were significant correlations between the elements in normal liver samples: S was associated with Cl, K, Br and Zn; Cl with S and Br; K with S, Br and Zn; Cu with Br. Zn with S and K. Br with S, Cl, K and Cu. Fe did not show significant associations with any other element. In contrast to simple statistical methods, which analyses content of elements separately one by one, dual hierarchical clustering analysis incorporates all elements at the same time and can be used to examine the linkage and interplay between multiple elements in tissue samples. Copyright © 2013 Elsevier GmbH. All rights reserved.

In-situ thermal analysis and macroscopical characterization of Mg-xCa and Mg-0.5Ca-xZn alloy systems

Energy Technology Data Exchange (ETDEWEB)

Farahany, Saeed [Department of Materials Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Bakhsheshi-Rad, Hamid Reza, E-mail: Rezabakhsheshi@gmail.com [Department of Materials Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Idris, Mohd Hasbullah [Department of Materials Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Abdul Kadir, Mohammed Rafiq [Medical Implants Technology Group, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Department of Biomechanics and Biomedical Materials, Faculty of Biomedical Engineering and Health Sciences, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Lotfabadi, Amir Fereidouni [Department of Manufacturing and Industrial Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Ourdjini, Ali [Department of Materials Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia)

2012-01-10

Highlights: Black-Right-Pointing-Pointer The effect of Ca and Zn addition on Mg-Ca and Mg-Ca-Zn were investigated. Black-Right-Pointing-Pointer Ca and Zn addition decreased solid fraction at coherency point. Black-Right-Pointing-Pointer T{sub N}-T{sub DCP} increased by adding Ca and Zn in Mg-Ca and Mg-Ca-Zn, respectively. Black-Right-Pointing-Pointer Three reactions were detected when Zn/Ca atomic ratio less than 1.25 in Mg-Ca-Zn. Black-Right-Pointing-Pointer A new peak Mg{sub 51}Zn{sub 20} was identified in Mg-0.5Ca-9Zn in addition of other peaks. - Abstract: This research described the identification phases by thermal analysis and microscopy inspection of Mg-xCa and Mg-0.5%Ca-xZn alloys that were solidified at slow cooling rate. Analysis of cooling curve after Ca addition shows the evolution of the Mg{sub 2}Ca intermetallic phase at around 520 Degree-Sign C in addition to {alpha}-Mg phase. First derivative curves of alloys after the addition of Zn to Mg-0.5Ca alloy reveals three peaks related to {alpha}-Mg, Mg{sub 2}Ca and Ca{sub 2}Mg{sub 6}Zn{sub 3} for alloys that have Zn/Ca atomic ratio less than 1.23. The peak of Mg{sub 2}Ca reaction on the first derivative curves disappeared for alloys containing Zn/Ca ratio more than 1.23. A new peak was also observed at 330 Degree-Sign C for Mg-0.5Ca-9Zn which was identified as Mg{sub 51}Zn{sub 20}. Solid fraction at coherency point decreased with increasing Ca and Zn elements. However, coherency time and difference between the nucleation and coherency temperatures (T{sub N}-T{sub DCP}) increased by adding Ca and Zn in Mg-Ca and Mg-Ca-Zn systems.

The Effect of Zn-Al-Hydrotalcites Composited with Calcium Stearate and β-Diketone on the Thermal Stability of PVC

Directory of Open Access Journals (Sweden)

Runjuan Wen

2011-03-01

Full Text Available A clean-route synthesis of Zn-Al-hydrotalcites (Zn-Al-LDHs using zinc oxide and sodium aluminate solution has been developed. The as-obtained materials were characterized by X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FT-IR, and scanning electron microscopy (SEM. The effects of metal ions at different molar ratios on the performance of hydrotalcites were discussed. The results showed that the Zn-Al-hydrotalcites can be successfully synthesized at three different Zn/Al ratios of 3:1, 2:1 and 1:1. Thermal aging tests of polyvinyl chloride (PVC mixed with Zn-Al-LDHs, calcium stearate (CaSt2 and β-diketone were carried out in a thermal aging test box by observing the color change. The results showed that Zn-Al-LDHs can not only enhance the stability of PVC significantly due to the improved capacity of HCl-adsorption but also increase the initial stability and ensure good-initial coloring due to the presence of the Zn element. The effects of various amounts of Zn-Al-LDHs, CaSt2 and β-diketone on the thermal stability of PVC were discussed. The optimum composition was determined to be 0.1 g Zn-Al-LDHs, 0.15 g CaSt2 and 0.25 g β-diketone in 5 g PVC.

Interfering elements in activation analysis. Study of instrumental analysis possibilities for the groups: Sc-Zn, Hg-Se and As-Sb-Br

International Nuclear Information System (INIS)

Figueiredo, A.M.G.; Atalla, L.T.

1979-01-01

The determination of the elements present in the groups Sc-Zn, Hg-Se and As-Sb-Br represents a classical problem in thermal neutron activation analysis, since the energy values of the gamma-ray photopeaks of the radioisotopes of these elements formed by thermal neutron activation are very closely located in the spectrum. A study is presented of the possibility of simultaneous instrumental determination of these elements by means of the spectrum stripping technique. For this purpose, artificial mixtures of the interfering elements, in varying proportions, were prepared. Radiochemical separations procedures for the above mentioned elements were also studied by means of tracers. (Author) [pt

[Analysis of inorganic elements in hydroponic Taraxacum mongolicum grown under different spectrum combinations by ICP-AES].

Science.gov (United States)

Chen, Xiao-li; Morewane, M B; Xue, Xu-zhang; Guo, Wen-zhong; Wang, Li-chun

2015-02-01

Dandelion (Taraxacum mongolicum) was hydroponically cultured in a completely enclosed plant factory, in which fluorescence and LED emitting spectra of different bands were used as the sole light source for plant growth. Effects of spectral component on the growth of dandelion were studied and the contents of ten inorganic elements such as K, P, Ca, Mg, Na, Fe, Mn, Zn, Cu and B in dandelion were analyzed by ICP-AES technology. The results showed that: (1) Under the condition of similar photosynthetic active radiation (PAR), single R or combined spectrums of FLRB were beneficial for biomass accumulation, while single B was the contrary; (2) Macroelements content ratio in Taraxacum mongolicum grown under FLwas K:Ca:P:Mg : Na=79.74:32.39:24.32:10.55:1.00, microelements content ratio was Fe:Mn:B:Zn:Cu = 9.28:9.71:3.82:2.08:1.00; (3) Red light (peak at 660 nm) could promote the absorptions of Ca, Fe, Mn, Zn, while absorption of Cu was not closely related to spectral conditions; (4) Thehighest accumulation of Ca, Na, Mn and Zn were obtained in aerial parts of Taraxacum mongolicum plants grown under pure red spectrum R, while the accumulation of the rest six elements reached the highest level under the mixed spectrum FLRB.

Electrodeposition of Zn and Cu–Zn alloy from ZnO/CuO precursors in deep eutectic solvent

Energy Technology Data Exchange (ETDEWEB)

Xie, Xueliang [State Key Laboratory of Advanced Special Steel & Shanghai Key Laboratory of Advanced Ferrometallurgy & School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Zou, Xingli, E-mail: xinglizou@shu.edu.cn [State Key Laboratory of Advanced Special Steel & Shanghai Key Laboratory of Advanced Ferrometallurgy & School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Lu, Xionggang, E-mail: luxg@shu.edu.cn [State Key Laboratory of Advanced Special Steel & Shanghai Key Laboratory of Advanced Ferrometallurgy & School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Lu, Changyuan; Cheng, Hongwei; Xu, Qian [State Key Laboratory of Advanced Special Steel & Shanghai Key Laboratory of Advanced Ferrometallurgy & School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Zhou, Zhongfu [State Key Laboratory of Advanced Special Steel & Shanghai Key Laboratory of Advanced Ferrometallurgy & School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Institute of Mathematics and Physics, Aberystwyth University, Aberystwyth SY23 3BZ (United Kingdom)

2016-11-01

Graphical abstract: Micro/nanostructured Zn and Cu–Zn alloy films have been electrodeposited directly from ZnO/CuO precursors in ChCl/urea-based DES, the typical nucleation-growth mechanism and the micro/nanostructures-formation process are determined. Display Omitted - Highlights: • Micro/nanostructured Zn films have been electrodeposited directly from ZnO precursor in deep eutectic solvent (DES). • The morphology of the Zn electrodeposits depends on the cathodic potential and temperature. • The electrodeposited Zn films exhibit homogeneous morphologies with controllable particle sizes and improved corrosion resistance. • Cu–Zn alloy films have also been electrodeposited directly from their metal oxides precursors in DES. - Abstract: The electrodeposition of Zn and Cu–Zn alloy has been investigated in choline chloride (ChCl)/urea (1:2 molar ratio) based deep eutectic solvent (DES). Cyclic voltammetry study demonstrates that the reduction of Zn(II) to Zn is a diffusion-controlled quasi-reversible, one-step, two electrons transfer process. Chronoamperometric investigation indicates that the electrodeposition of Zn on a Cu electrode typically involves three-dimensional instantaneous nucleation with diffusion-controlled growth process. Micro/nanostructured Zn films can be obtained by controlling the electrodeposition potential and temperature. The electrodeposited Zn crystals preferentially orient parallel to the (101) plane. The Zn films electrodeposited under more positive potentials and low temperatures exhibit improved corrosion resistance in 3 wt% NaCl solution. In addition, Cu–Zn alloy films have also been electrodeposited directly from CuO–ZnO precursors in ChCl/urea-based DES. The XRD analysis indicates that the phase composition of the electrodeposited Cu–Zn alloy depends on the electrodeposition potential.

A Simple Method for the Preparation of ZnO Prickly Spheres

Institute of Scientific and Technical Information of China (English)

Da Zhi LI; Xin Yu SONG; Si Xiu SUN; Jin Xin GUO

2004-01-01

The synthesis of ZnO prickly spheres using precipitation followed by heating treatment was investigated. Zn(OH)2 precursor was prepared by precipitation process using Zn(CH3COO)2·2H2O in mixed 1-propanol-water solvent. Sodium dodecyl sulfate (SDS) as the anionic surfactant was added to control the morphology. The size and structure of ZnO prickly spheres were studied using XRD, TEM and SEM. The results showed that the morphologies and size of the spheres strongly depended on the volume ratio of 1-propanol /water and molar ratio of SDS/Zn2+. ZnO prickly spheres composed of nanorods could be obtained, when the volume ratio of 1-propanol/water = 2:3 and the molar ratio of Zn2+/SDS ≈ 450:1.

Origin of localized states in zinc-blende ZnCdSe thin films and the influence on carrier relaxation of self-assembled ZnTe/ZnCdSe quantum dots

International Nuclear Information System (INIS)

Lee, Ling; Dai, Yue-Ru; Yang, Chu-Shou; Fan, Wen-Chung; Chou, Wu-Ching

2015-01-01

Highlights: • The localized emission in zinc-blende ZnCdSe is induced by excess selenium. • An optimized growth is demonstrated as the VI/II ratio approaches unity. • Size-independent lifetimes are observed in ZnTe/ZnCdSe quantum dots. • Localized electrons in the capping layer dominate size-independent lifetimes. - Abstract: This study discovered the origin of deep level emission in zinc-blende ZnCdSe thin films grown by molecular beam epitaxy, in which a localization behavior was noticed. Pronounced deep level emission observed in films grown under a VI/II ratio of 1.74 (Se-accumulated regime) could be suppressed by a lower VI/II ratio of 1.04 (intermediate regime) and 0.74 (metal-rich regime). Hence the localized states could be correlated to excess selenium accumulated at the growth surface. The localized states also influence the carrier relaxation process of self-assembled ZnTe quantum dots embedded in a ZnCdSe matrix. Once quantum dots surmount the wetting layer, localized electrons in the capping layer dominate the type-II transition and exhibit size-independent lifetimes

Identification of Zn vacancies in ZnTe doped with Cl and I

Science.gov (United States)

Asoka-Kumar, Palakkal; Alatalo, Matti; Wang, Wen

1997-03-01

The doping difficulties of II-VI semiconductors are well known. For example, ZnTe can be doped easily to have p-type conductivity but not n-type. We examined Cl and I doped ZnTe using positron annihilation spectroscopy to understand the role of vacancies in the compensation mechanism. The annihilation line shapes from inner-shell electrons can be used for elemental identification[1]. Results from ZnTe:Cl and ZnTe:I show an enhancement of annihilations with Te electrons compared to undoped samples, and is explained as arising due to first neighbor of a Zn vacancy. Theoretical calculations of the annihilation line shapes from bulk ZnTe and Zn and Te vacancies will also be presented. This work was supported in part by the US DOE under contract No. DE-AC02-76CH00016. [1] P. Asoka-Kumar, M. Alatalo, V.J. Ghosh, A.C. Kruseman, B. Nielsen, and K.G. Lynn, Phys. Rev. Lett. Vol. 77, 2097 (1996).

Luminescence of one dimensional ZnO, GeO{sub 2}–Zn{sub 2}GeO{sub 4} nanostructure through thermal evaporation of Zn and Ge powder mixture

Energy Technology Data Exchange (ETDEWEB)

Pham, Vuong-Hung, E-mail: vuong.phamhung@hust.edu.vn; Kien, Vu Trung; Tam, Phuong Dinh; Huy, Pham Thanh

2016-07-15

Graphical abstract: - Highlights: • ZnO and GeO{sub 2}–ZnGeO{sub 4} nanowires were fabricated by thermal evaporation of Zn and Ge powder mixture. • Morphology of specimens were observed to have a nanowire structure to rod-like morphology. • Strong NBE emission band with suppressed visible green emission band were observed on the dominant ZnO nanowires. • Strong emission of ∼530 nm were observed on the GeO{sub 2}–Zn{sub 2}GeO{sub 4} nanowires. - Abstract: This paper reports the first attempt for fabrication of thermal evaporated Zn–Ge powder mixture to achieve near-band-edge (NBE) emission of ZnO and visible emission of GeO{sub 2}–Zn{sub 2}GeO{sub 4} nanowires with controllable intensities. The nanowires were fabricated by thermal evaporation of Zn and Ge powder mixture, particularly, by using different Zn:Ge ratio, temperature and evaporated times. The morphology of nanowires was depended on the Zn and Ge ratio that was observed to have a nanowire structure to rod-like morphology. The thermal evaporation of Zn:Ge powder mixture resulted in formation of dominant ZnO or GeO{sub 2}–Zn{sub 2}GeO{sub 4} nanowires as a function of evaporated parameters. These results suggest that the application of thermal evaporation of Zn and Ge mixture for potential application in synthesis of ZnO or GeO{sub 2}–Zn{sub 2}GeO{sub 4} nanowires for optoelectronic field.

Trace element concentrations in the fruit peels and trunks of Musa paradisiaca.

Science.gov (United States)

Selema, M D; Farago, M E

1996-08-01

Chemical analyses for the elementary compositions of the ashes of the fruit peels and trunks of the tropical plantain Musa paradisiaca have been undertaken. The elements, categorized as trace elements, generally are found to have higher mean concentrations in the fruit peels than in the trunks (except in the case of Zn). Their peel-trunk uptake ratios have been calculated and range between 1 and 4, showing normal levels of accumulations in the fruit peels over the trunks.

Effect of different processes and Ti/Zn molar ratios on the structure, morphology, and enhanced photoelectrochemical and photocatalytic performance of Ti3+ self-doped titanium-zinc hybrid oxides

Science.gov (United States)

Fu, Rongrong; Wang, Qingyao; Gao, Shanmin; Wang, Zeyan; Huang, Baibiao; Dai, Ying; Lu, Jun

2015-07-01

Ti3+ self-doped titanium-zinc hybrid oxides with different phase compositions and morphologies were successfully synthesized using Zn powder as the reductant and Zn source by a chemical-reduction precipitation method with subsequent thermal treatment. The fabricated Ti3+ self-doped TiO2(A)/TiO2(R), TiO2(A)/TiO2(R)/ZnTiO3, and TiO2(A)/ZnO heterojunctions were characterized by X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and UV-Vis diffuse reflectance spectroscopy. The effects of various Ti/Zn molar ratios and preparation processes on the structural, morphological, optical, photocurrent and photocatalytic properties of the resultant samples were investigated systematically. Results reveal that Ti3+ self-doping enhances the photoabsorption capability of titanium-zinc hybrid oxides in the visible-light region. Moreover, different processes and Ti/Zn molar ratios play great influences on the structure, morphology, optical, photocurrent and photocatalytic properties of the final products. Ti3+ self-doped titanium-zinc hybrid oxides exhibit excellent photocurrent and photocatalytic activity than pure TiO2 and ZnTiO3 under visible-light irradiation (λ ≥ 400 nm). The most active Ti3+ self-doped titanium-zinc hybrid oxides photoanode presents significantly improved water splitting performance. The synergistic effect between the Ti3+ self-doped and heterojunctions is responsible for the enhanced performance of these materials.

Studies on the relationship between trace element (selenium, zinc) accumulation in hair and metabolism in body of rabbit by using 75Se and 65Zn tracer technique

International Nuclear Information System (INIS)

Cai Xuelin; Song Xuehua; Wu Suqiong

1999-01-01

In the study, the rabbit was used as experimental animal. After 2 months of feeding the diet with different levels of Se or Zn, five animals from each group were given an oral dose of Na 2 75 SeO 3 or 65 ZnSO 4 solution, respectively. The process of absorption, exertion, accumulation and transfer of isotopes to the hair were determined, and the tissues retention of 75 Se or 65 Zn were also examined at the end of the experiments. The results obtained from the measurement of radioactive change of back hair in each group animal after the oral intake of 75 Se or 65 Zn showed that the 75 Se or 65 Zn transfer to hair were fast. At the seventh and fifth day after dosing, the 75 Se or 65 Zn were determined in the down-end section and upper-end section of back hair, and the radioactivity increased with time. At the first, the radioactivity in down-end section was higher than that of the upper-end section. However, at the end of experiment the upper-end section was higher than the down-end section. The data obtained from the different measuring point indicated that the accumulation, distribution of trace element in hair was not even. there was extended process from the down-end to the upper-end of hair and accumulation in upper-end section. The content of 75 Se or 65 Zn in hair was related to the level of Se or Zn in diet. However, there were difference among the different trace elements

Resistive switching in ZnO/ZnO:In nanocomposite

Science.gov (United States)

Khakhulin, D. A.; Vakulov, Z. E.; Smirnov, V. A.; Tominov, R. V.; Yoon, Jong-Gul; Ageev, O. A.

2017-11-01

A lot of effort nowadays is put into development of new approaches to processing and storage of information in integrated circuits due to limitations in miniaturisation. Our research is dedicated to one of actively developed concepts - oxide based resistive memory devices. A material that draws interest due to its promising technological properties is ZnO but pure ZnO lacks in performance in comparison with some other transition metal oxides. Thus our work is focused on improvement of resistive switching parameters in ZnO films by creation of complex nanocomposites. In this work we report characterisation of a nanocomposite based on PLD grown ZnO films with inclusions of In. Such solution allows us to achieve improvements of main parameters that are critical for ReRAM device: RHRS/RLRS ratio, endurance and retention.

Preparation and characterization of electrodeposited ZnO and ZnO:Co nanorod films for heterojunction diode applications

Energy Technology Data Exchange (ETDEWEB)

Caglar, Yasemin, E-mail: yasemincaglar@anadolu.edu.tr [Anadolu University, Science Faculty, Physics Department, Eskisehir (Turkey); Arslan, Andaç [Eskisehir Osmangazi University, Art and Science Faculty, Chemistry Department, Eskisehir (Turkey); Ilican, Saliha [Anadolu University, Science Faculty, Physics Department, Eskisehir (Turkey); Hür, Evrim [Eskisehir Osmangazi University, Art and Science Faculty, Chemistry Department, Eskisehir (Turkey); Aksoy, Seval; Caglar, Mujdat [Anadolu University, Science Faculty, Physics Department, Eskisehir (Turkey)

2013-10-15

Highlights: •Undoped and Co-doped ZnO films were deposited on p-Si by electrodeposition method. •The effects of Co doping on some properties of ZnO films were investigated. •ZnO morphology was converted uniform multi-oriented rods with incorporation of Co. •Co-doped ZnO nanorod films showed a multi-oriented spear-like structure. -- Abstract: Well-aligned undoped and Co-doped nanorod ZnO films were grown by electrochemical deposition onto p-Si substrates from an aqueous route. Aqueous solution of Zn(NO{sub 3}){sub 2}⋅6H{sub 2}O and hexamethylenetetramine (HMT) were prepared using triple distilled water. Two different atomic ratios of Co(NO{sub 3}){sub 2}⋅6H{sub 2}O were used as a dopant element. Electrodepositions were carried out in a conventional three electrode cell for the working electrode (p-Si), reference electrode (Ag/AgCl, sat.) and counter electrode (platin wire). The effects of Co doping on the structural, morphological and electrical properties of ZnO films were investigated. X-ray diffraction (XRD) measurement showed that the undoped ZnO nanorod film was crystallized in the hexagonal wurtzite phase and presented a preferential orientation along the c-axis. Only one peak, corresponding to the (0 0 2) phase, appeared on the diffractograms. The lattice parameters and texture coefficient values were calculated. The nanorods were confirmed by the field emission scanning electron microscopy (FE-SEM) measurements. The FE-SEM image showed that the ZnO nanorods grow uniformly on the substrates, providing a surface with fairly homogeneous roughness. The surface morphology was transformed into uniform multi-oriented rods with incorporation of Co. Co-doped ZnO nanorod films showed a multi-oriented spear-like structure. The diffuse reflectance spectra of the films were measured and the optical band gap values were determined using Kubelka–Munk theory. The van der Pauw method was used to measure the sheet resistance of the films. The sheet resistance

Element enrichment and U-series isotopic characteristics of the hydrothermal sulfides at Jade site in the Okinawa Trough

Institute of Scientific and Technical Information of China (English)

无

2009-01-01

The geochemical and U-series isotopic characteristics of hydrothermal sulfide samples from the Jade site (127°04.5′E, 27°15′N, water depth 1300-1450 m) at Jade site in the Okinawa Trough were analyzed. In the hydrothermal sulfide samples bearing sulfate (samples HOK1 and HOK2), the LREEs are relatively enriched. All the hydrothermal sulfide samples except HOK1 belong to Zn-rich hydrothermal sulfide. In comparison with Zn-rich hydrothermal sulfides from other fields, the contents of Zn, Pb, Ag, Cd, Au and Hg are higher, the contents of Fe, Al, Cr, Co, Ni, Sr, Te, Cs, Ti and U lower, and the 210Pb radioactivity ratios and 210Pb/Pb ratios very low. In the hydrothermal sulfide mainly composed of sphalerite, the correlations between rare elements Hf and U, and Hf and Mn as well as that between dispersive elements Ga and Zn, are strongly positive; also the contents of Au and Ag are related to Fe-sulfide, because the low temperature promotes enrichment of Au and Ag. Meanwhile, the positive correlations between Fe and Bi and between Zn and Cd are not affected by the change of mineral assemblage. Based on the 210Pb/Pb ratios of hydrothermal sulfide samples (3.99×10-5-5.42×10?5), their U isotopic composition (238U content 1.15-2.53 ppm, 238U activity 1.07-1.87 dpm/g, 234U activity 1.15-2.09 dpm/g and 234U/238U ratio 1.07-1.14) and their 232Th and 230Th contents are at base level, and the chronological age of hydrothermal sulfide at Jade site in the Okinawa Trough is between 200 and 2000 yr.

Liquid petroleum gas sensing application of ZnO/CdO:ZnO nanocomposites at low temperature

Science.gov (United States)

Rajput, Jeevitesh K.; Pathak, T. K.; Kumar, V.; Swart, H. C.; Purohit, L. P.

2018-04-01

ZnO and CdO:ZnO nanoparticles are synthesized by sol-gel precipitation method. The structural analysis shows composite structure for CdO:ZnO nanoparticles with (002) and (111) phase. The SEM images show wedge like morphology and 3-D hexagonal morphology with ˜110 nm in size. The uniform growth of CdO:ZnO nanoparticles were observed in EDS element mapping image. LPG sensing was observed for CdO:ZnO nanoparticle with rapid sensing response 8.69% at operating temperature 50°C. This sensing response can be accounted due by absorption ions reactions at low operating temperature.

Evaluation of local trace element status and 8-Iso-prostaglandin F2α concentrations in patients with Tinea pedis.

Science.gov (United States)

Miraloglu, Meral; Kurutas, Ergul Belge; Ozturk, Perihan; Arican, Ozer

2016-01-01

Tinea pedis (TP) is an infection of the feet caused by fungi. The infectious diseases caused by dermatophytes are mainly related to the enzymes produced by these fungi. Up to the now, the local 8-iso-prostaglandin F2α (8-iso-PGF2α), concentration as oxidative stress biomarker and trace elements status have not been published in patients with TP. The aim of this study is to evaluate the relationship between oxidative stress and trace elements (Cu, Zn, Se), and to evaluate the ratios of Cu/Zn and Cu/Se in this disorder. Forty-three consecutive patients with a diagnosis of unilateral interdigital TP were enrolled in this study. The samples were obtained by scraping the skin surface. 8-iso-PGF2α concentrations in scraping samples were determined by ELISA. In addition, the levels of Se, Zn and Cu in scraping samples were determined on flame and furnace atomic absorption spectrophotometer using Zeeman background correction. Oxidative stress was confirmed by the significant elevation in 8-iso-PGF2α concentrations (p iso-PGF2α parameters, but negative correlations between Se-Cu; Se-8-iso-PGF2α parameters in lesional area. Furthermore, the ratios of Cu/Zn and Cu/Se were significantly higher on the lesional area than the non-lesional area (p iso-PGF2α and trace elements in patients with TP (p > 0.05). Our results showed that there is a possible link between oxidative stress (increased 8-iso-PGF2α concentrations) and imbalanced of trace elements status in lesional area of TP patients. The use of antifungal agents together with both Zn and Se drugs could be helpful in the both regression of disease and in shortening the duration of disease.

Elemental composition of Malawian rice.

Science.gov (United States)

Joy, Edward J M; Louise Ander, E; Broadley, Martin R; Young, Scott D; Chilimba, Allan D C; Hamilton, Elliott M; Watts, Michael J

2017-08-01

Widespread potential dietary deficiencies of calcium (Ca), iron (Fe), iodine (I), selenium (Se) and zinc (Zn) have been identified in Malawi. Several deficiencies are likely to be compounded by high phytic acid (PA) consumption. Rice (Oryza sativa) is commonly consumed in some Malawian populations, and its mineral micronutrient content is important for food security. The considerable irrigation requirements and flooded conditions of paddy soils can also introduce or mobilise potentially toxic elements including arsenic (As), cadmium (Cd) and lead (Pb). The aim of this study was to determine the mineral composition of rice sampled from farmers' fields and markets in Malawi. Rice was sampled from 18 extension planning areas across Malawi with 21 white (i.e. polished) and 33 brown samples collected. Elemental composition was determined by inductively coupled plasma-mass spectrometry (ICP-MS). Arsenic speciation was performed using high-performance liquid chromatography (HPLC)-ICP-MS. Concentration of PA was determined using a PA-total phosphorus assay. Median total concentrations (mg kg -1 , dry weight) of elements important for human nutrition in brown and white rice, respectively, were: Ca = 66.5 and 37.8; Cu = 3.65 and 2.49; Fe = 22.1 and 7.2; I = 0.006 and rice samples, respectively, median PA concentrations were 5438 and 1906 mg kg -1 , and median PA:Zn molar ratios were 29 and 13. Concentrations of potentially toxic elements (mg kg -1 , dry weight) in brown and white rice samples, respectively, were: As = 0.030 and 0.006; Cd  ≤ 0.002 and 0.006; Pb = 0.008 and 0.008. Approximately 95 % of As was found to be inorganic As, where this could be quantified. Malawian rice, like the more widely consumed staple grain maize, contains inadequate Ca, I, Se or Zn to meet dietary requirements. Biofortification strategies could significantly increase Se and Zn concentrations and require further investigation. Concentrations of Fe in rice grain varied

Study on Characteristics of Soil Elements Bio-availability and Their Interrelationship in Black Soil Area of Jilin Province

Science.gov (United States)

Wang, D. Y.

2015-12-01

Abstract: Based on systematic field investigation and surface soil(0-20cm) sampling in the middle part of Jilin province where the soil type mainly consists of black soil and chernozem, soil total content and bio-available content of Fe, Fe, Ca, Mg, K, P, Cu, Zn, Ni, Cr, B, Cd, As were tested. This paper summarizes the geochemical characteristics of the soil elements and takes the ratio of bio-available content to total content as the bio-availability characteristic of each element in soil and studies the interrelationship between their geochemical characteristics of bio-availability by PCA and correlation analysis. Cd、Cr、Ni、Zn、P、Ca are selected out by PCA due to the similar impact under 4 principal components. And their correlation analysis results indicate: the correlation coefficients between heavy metal elements(Cr, Cd, Zn, Ni) bio-availability are significant positive, i.e., the same spatial variation trends are found between them in study area; the same relationships are also found between the bioavailability of P and 4 heavy metal elements (Cr, Cd, Zn, Ni), the promotion of the bioavailability of heavy metal elements goes with P; However, the correlation coefficients between heavy metal(Cr, Cd, Zn, Ni) bio-availability and Ca are mostly significant negative and the adverse spatial variation trends are found between them. The promotion of the bioavailability of heavy metal elements goes against Ca. Key words: soil geochemistry; soil heavy metals; elements interaction; bio-availability

Association between essential trace and toxic elements in scalp hair samples of smokers rheumatoid arthritis subjects

Energy Technology Data Exchange (ETDEWEB)

Afridi, Hassan Imran, E-mail: hassanimranafridi@yahoo.com [Mechanical and Manufacturing Engineering, Dublin City University, Dublin, Ireland. (Ireland); National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro (Pakistan); Kazi, Tasneem Gul, E-mail: tgkazi@yahoo.com [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro (Pakistan); Brabazon, Dermot, E-mail: dermot.brabazon@dcu.ie [Mechanical and Manufacturing Engineering, Dublin City University, Dublin, Ireland. (Ireland); Naher, Sumsun, E-mail: sumsun.naher@dcu.ie [Mechanical and Manufacturing Engineering, Dublin City University, Dublin, Ireland. (Ireland)

2011-12-15

The incidence of rheumatoid arthritis (RA) has been increased among people who possess habit of tobacco smoking. In the present study, zinc (Zn), copper (Cu), manganese (Mn), lead (Pb) and cadmium (Cd) were determined in scalp hair samples of smokers and nonsmokers RA patients, residents of Dublin, Ireland. For comparison purposes scalp hair samples of age and sex matched healthy smokers and nonsmokers were also analyzed. The concentrations of understudied elements were measured by inductive coupled plasma atomic emission spectrophotometer, prior to microwave assisted acid digestion. The validity and accuracy of methodology was checked using certified reference material (NCS ZC 81002b) and by the conventional wet acid digestion method on the same certified reference material and on real samples. The mean hair Zn, Cu and Mn contents were significantly lower in smokers and nonsmokers RA patients as compared to healthy individuals (p = 0.01-0.001). Whereas the concentrations of Cd and Pb were significantly higher in scalp hair samples of RA patients of both group (p < 0.001). The referent smokers have high level of Cd and Pb in their scalp hair samples as compared to those had not smoking tobacco (p < 0.01). The ratio of Cd and Pb to Zn, Cu and Mn in scalp hair samples was also calculated. The Cd/Zn ratio was higher in smoker RA patients with related to nonsmoker RA and referents. This study is compelling evidence in support of positive associations between toxic elements, cigarette smoking, deficiency of essential trace elements and risk of arthritis.

Association between essential trace and toxic elements in scalp hair samples of smokers rheumatoid arthritis subjects

International Nuclear Information System (INIS)

Afridi, Hassan Imran; Kazi, Tasneem Gul; Brabazon, Dermot; Naher, Sumsun

2011-01-01

The incidence of rheumatoid arthritis (RA) has been increased among people who possess habit of tobacco smoking. In the present study, zinc (Zn), copper (Cu), manganese (Mn), lead (Pb) and cadmium (Cd) were determined in scalp hair samples of smokers and nonsmokers RA patients, residents of Dublin, Ireland. For comparison purposes scalp hair samples of age and sex matched healthy smokers and nonsmokers were also analyzed. The concentrations of understudied elements were measured by inductive coupled plasma atomic emission spectrophotometer, prior to microwave assisted acid digestion. The validity and accuracy of methodology was checked using certified reference material (NCS ZC 81002b) and by the conventional wet acid digestion method on the same certified reference material and on real samples. The mean hair Zn, Cu and Mn contents were significantly lower in smokers and nonsmokers RA patients as compared to healthy individuals (p = 0.01–0.001). Whereas the concentrations of Cd and Pb were significantly higher in scalp hair samples of RA patients of both group (p < 0.001). The referent smokers have high level of Cd and Pb in their scalp hair samples as compared to those had not smoking tobacco (p < 0.01). The ratio of Cd and Pb to Zn, Cu and Mn in scalp hair samples was also calculated. The Cd/Zn ratio was higher in smoker RA patients with related to nonsmoker RA and referents. This study is compelling evidence in support of positive associations between toxic elements, cigarette smoking, deficiency of essential trace elements and risk of arthritis.

A boron and gallium co-doped ZnO intermediate layer for ZnO/Si heterojunction diodes

Science.gov (United States)

Lu, Yuanxi; Huang, Jian; Li, Bing; Tang, Ke; Ma, Yuncheng; Cao, Meng; Wang, Lin; Wang, Linjun

2018-01-01

ZnO (Zinc oxide)/Si (Silicon) heterojunctions were prepared by depositing n-type ZnO films on p-type single crystal Si substrates using magnetron sputtering. A boron and gallium co-doped ZnO (BGZO) high conductivity intermediate layer was deposited between aurum (Au) electrodes and ZnO films. The influence of the BGZO layer on the properties of Au/ZnO contacts and the performance of ZnO/Si heterojunctions was investigated. The results show an improvement in contact resistance by introducing the BGZO layer. Compared with the ZnO/Si heterojunction, the BGZO/ZnO/Si heterojunction exhibits a larger forward current, a smaller turn-on voltage and higher ratio of ultraviolet (UV) photo current/dark current.

Flexible Memristive Devices Based on InP/ZnSe/ZnS Core-Multishell Quantum Dot Nanocomposites.

Science.gov (United States)

Kim, Do Hyeong; Wu, Chaoxing; Park, Dong Hyun; Kim, Woo Kyum; Seo, Hae Woon; Kim, Sang Wook; Kim, Tae Whan

2018-05-02

The effects of the ZnS shell layer on the memory performances of flexible memristive devices based on quantum dots (QDs) with an InP/ZnSe/ZnS core-multishell structure embedded in a poly(methylmethacrylate) layer were investigated. The on/off ratios of the devices based on QDs with an InP/ZnSe core-shell structure and with an InP/ZnSe/ZnS core-multishell structure were approximately 4.2 × 10 2 and 8.5 × 10 3 , respectively, indicative of enhanced charge storage capability in the latter. After bending, the memory characteristics of the memristive devices based on QDs with the InP/ZnSe/ZnS structure were similar to those before bending. In addition, those devices maintained the same on/off ratios for retention time of 1 × 10 4 s, and the number of endurance cycles was above 1 × 10 2 . The reset voltages ranged from -2.3 to -3.1 V, and the set voltages ranged from 1.3 to 2.1 V, indicative of reliable electrical characteristics. Furthermore, the possible operating mechanisms of the devices are presented on the basis of the electron trapping and release mode.

PIXE as a monitoring method on the behavior of elements in coastal sediments

International Nuclear Information System (INIS)

Matsuda, Y.; Ishiyama, T.; Ito, N.; Kiyoda, S.

1993-01-01

The chemical extraction + PIXE + NAA proposed in the previous paper as a monitoring method of the elemental behavior in the coastal sediments is appeared as a very useful technique in view of giving information on detail adsorption/ desorption behavior of transition metal ions. The ratios of reversible adsorption amounts to total adsorption with Mn and Co were comparatively high as 0.37 and 0.13, respectively. On the other hand, the ratios with Fe and Zn were very low as 0.01. Any eluting rates of Mn, Fe, Co and Zn were considerably greater with 0.01 M EDTA·2Na than with 0.2 M ammonium oxalate, which reflect the sizes of the stability constants of chelates with possible forms at extraction. (1 tab.)

Composites of Laminar Nanostructured ZnO and VOx-Nanotubes Hybrid as Visible Light Active Photocatalysts

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Eglantina Benavente

2018-02-01

Full Text Available A series of hybrid heterostructured nanocomposites of ZnO with V2O5 nanotubes (VOx-NTs in different mixing ratios were synthesized, with the aim of reducing the recombination of photoinduced charge carriers and to optimize the absorption of visible light. The study was focused on the use of heterostructured semiconductors that can extend light absorption to the visible range and enhance the photocatalytic performance of ZnO in the degradation of methylene blue as a model pollutant. The addition of VOx-NTs in the synthesis mixture led to a remarkable performance in the degradation of the model dye, with hybrid ZnO (stearic acid/VOx-NTs at a ratio of 1:0.06 possessing the highest photocatalytic activity, about seven times faster than pristine zinc oxide. Diffuse reflectance spectroscopic measurements and experiments in the presence of different trapping elements allowed us to draw conclusions regarding the band positions and photocatalytic degradation mechanism. The photocatalytic activity measured in three subsequent cycles showed good reusability as no significant loss in efficiency of dye degradation was observed.

Distribution and leaching characteristics of trace elements in ashes as a function of different waste fuels and incineration technologies.

Science.gov (United States)

Saqib, Naeem; Bäckström, Mattias

2015-10-01

Impact of waste fuels (virgin/waste wood, mixed biofuel (peat, bark, wood chips) industrial, household, mixed waste fuel) and incineration technologies on partitioning and leaching behavior of trace elements has been investigated. Study included 4 grate fired and 9 fluidized boilers. Results showed that mixed waste incineration mostly caused increased transfer of trace elements to fly ash; particularly Pb/Zn. Waste wood incineration showed higher transfer of Cr, As and Zn to fly ash as compared to virgin wood. The possible reasons could be high input of trace element in waste fuel/change in volatilization behavior due to addition of certain waste fractions. The concentration of Cd and Zn increased in fly ash with incineration temperature. Total concentration in ashes decreased in order of Zn>Cu>Pb>Cr>Sb>As>Mo. The concentration levels of trace elements were mostly higher in fluidized boilers fly ashes as compared to grate boilers (especially for biofuel incineration). It might be attributed to high combustion efficiency due to pre-treatment of waste in fluidized boilers. Leaching results indicated that water soluble forms of elements in ashes were low with few exceptions. Concentration levels in ash and ash matrix properties (association of elements on ash particles) are crucial parameters affecting leaching. Leached amounts of Pb, Zn and Cr in >50% of fly ashes exceeded regulatory limit for disposal. 87% of chlorine in fly ashes washed out with water at the liquid to solid ratio 10 indicating excessive presence of alkali metal chlorides/alkaline earths. Copyright © 2015. Published by Elsevier B.V.

Ultra-long Zn{sub 2}SnO{sub 4}-ZnO microwires based gas sensor for hydrogen detection

Energy Technology Data Exchange (ETDEWEB)

Fan, Hong [School of Resources and Civil Engineering, Northeastern University, Shenyang 110819 (China); Xu, Shucong [School of Material Science & Engineering, Shandong University, Jinan 250061 (China); Cao, Xianmin; Liu, Daoxi; Yin, Yaoyu; Hao, Haiyong; Wei, Dezhou [School of Resources and Civil Engineering, Northeastern University, Shenyang 110819 (China); Shen, Yanbai, E-mail: shenyanbai@mail.neu.edu.cn [School of Resources and Civil Engineering, Northeastern University, Shenyang 110819 (China)

2017-04-01

Highlights: • Ultra-long Zn{sub 2}SnO{sub 4}-ZnO microwires with excellent crystallinity and high yield were obtained. • The maximal length-to-diameter ratio of Zn{sub 2}SnO{sub 4}-ZnO microwires is approximately 1500. • Ultra-long Zn{sub 2}SnO{sub 4}-ZnO microwires show outstanding H{sub 2} sensing properties. - Abstract: Ultra-long Zn{sub 2}SnO{sub 4}-ZnO microwires were synthesized by thermal evaporation of the mixture of SnO{sub 2}, ZnO and C powders. Microstructural characterization by means of X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy showed that Zn{sub 2}SnO{sub 4}-ZnO microwires with excellent crystallinity were 2.8–3.2 μm in diameter and 4.0–4.2 mm in length. The maximal length-to-diameter ratio of Zn{sub 2}SnO{sub 4}-ZnO microwires is approximately 1500. H{sub 2} sensing properties showed that Zn{sub 2}SnO{sub 4}-ZnO microwires exhibited not only excellent reversibility to H{sub 2}, but also a good linear relationship between the sensor response and H{sub 2} concentration. The response time and recovery time decreased as the operating temperature increased. The highest sensor response of 9.6 to 1000 ppm H{sub 2} was achieved at an operating temperature of 300 °C. The electron depletion theory was used for explaining H{sub 2} sensing mechanism by the chemical adsorption and reaction of H{sub 2} molecules on the surface of Zn{sub 2}SnO{sub 4}-ZnO microwires.

Neutron-proton matrix element ratios of 21+ states in 58,60,62,64Ni

International Nuclear Information System (INIS)

Antalik, R.

1989-01-01

The neutron-proton matrix element ratios (η) for 2 1 + states of even Ni isotopes are investigated within the framework of the shell model quasiparticle random-phase approximation. The special attention is devoted to the dependence of η ratios on the radial neutron and proton ground-state density-distribution differences (Δ np ). This dependence is found to be about 0.5Δ np . The theoretical η ratios are 14-23% greater than the hydrodynamical limit. The theoretical Δ np dependence of η ratios enable us to understand the empirical η ratio results. 20 refs.; 2 figs.; 2 tabs

Studies on the transfer of Cs, Sr, Co, Mn and Zn from soil to plants and from medium to mushrooms by using radiotracer

International Nuclear Information System (INIS)

Ban-nai, Tadaaki; Muramatsu, Yasuyuki; Yoshida, Satoshi; Yanagisawa, Kei

1996-01-01

Radiotracer experiments were carried out to study radionuclide uptake by plants and mushrooms. Transfer factors of radionuclides from soil to leaf vegetables (cabbage, Chinese cabbage, komatsuna, spinach and lettuce) have been determined by radiotracers. The transfer factors of radioactive Cs, Sr, Mn, Co and Zn for edible parts of vegetables were 0.11, 0.24, 0.61, 0.05 and 0.52, respectively. The transfer factors of Mn, Co and Zn for spinach were higher than those for the other vegetables. The transfer factors of Cs for different organs of the leaf vegetables were rather homogeneous. The transfer factors of Sr and Mn were higher for older (outer) leaves than younger (inner) ones. In contrast to Sr and Mn, transfer factors of Zn for younger leaves were higher than those for older ones. In order to study radionuclide uptake by mushrooms, cultivation experiments in flasks were carried out using radiotracers, 137 Cs, 85 Sr, 60 Co, 54 Mn and 65 Zn. Four mushroom species Hebeloma vinosophyllum, Flammulina velutipes, Agrocybe cylindracea and Coprinus phlyctidosporus were used. In addition, Medicago sativa was also tested. Mushrooms tended to accumulate Cs, although there was a large difference between mushroom species. The concentration ratio had the highest value of 21 for Cs in vinosophyllum. The value was much higher than that in the plant sample. The present findings agreed with our previous observations in which Hebeloma species collected in forests contained large amount of 137 Cs. The effects of stable elements in the medium on the accumulations were investigated. The concentration ratios of Cs, Sr and Co were not influenced highly by coexisting stable elements in the medium. However, the ratio of Mn decreased as the amount of coexisting stable elements in the medium was increased. (J.P.N.)

A Three End-Member Mixing Model Based on Isotopic Composition and Elemental Ratio

Directory of Open Access Journals (Sweden)

Kon-Kee Liu Shuh-Ji Kao

2007-01-01

Full Text Available A three end-member mixing model based on nitrogen isotopic composition and organic carbon to nitrogen ratio of suspended particulate matter in an aquatic environment has been developed. Mathematical expressions have been derived for the calculation of the fractions of nitrogen or organic carbon originating from three different sources of distinct isotopic and elemental compositions. The model was successfully applied to determine the contributions from anthropogenic wastes, soils and bedrock-derived sediments to particulate nitrogen and particulate organic carbon in the Danshuei River during the flood caused by Typhoon Bilis in August 2000. The model solutions have been expressed in a general form that allows applications to mixtures with other types of isotopic compositions and elemental ratios or in forms other than suspended particulate matter.

ZnO Nanorods with Tunable Aspect Ratios Deriving from Oriented-attachment for Enhanced Performance in Quantum-dot Sensitized Solar Cells

International Nuclear Information System (INIS)

Wu, Dapeng; Wang, Xiaolu; Cao, Kun; An, Yipeng; Song, Xiaohui; Liu, Ning; Xu, Fang; Gao, Zhiyong; Jiang, Kai

2017-01-01

ZnO nanorods consisted of oriented aligned elongated-nanoparticles along the [0001] direction were readily prepared with tunable aspect ratios by a facile solvothermal method. An oriented-attachment growth mechanism was proposed based on time-dependent trails and first principle density function theory calculation. Control experiments indicated that the reaction medium played important roles to influence the oriented-attachment process and the aspect ratio could be tuned from ∼4.6 to ∼16.0 by simply altering the precursor dosages. The as-prepared ZnO nanorods were applied as photoanode materials in quantum-dot sensitized solar cells. The large pore size in the film structure and rough surface of the nanorod could enhance the quantum dots loading amounts and light scattering effect. In addition, the orderly aligned primary ENPs minimized the grain boundaries for suppressed recombination and provided a direct pathway for increased electron diffusion length. Meanwhile, the enhanced film hydrophilicity facilitated the electrolyte penetration and the regeneration of oxidized sensitizers. Therefore, a high power conversion efficiency of ∼4.83% was demonstrated, indicating substantial improvement compared with that of traditional nanoparticle based device (∼3.54%).

Composition and strain effects in Type I and Type II heterostructure ZnSe/Cd(Zn)S and ZnSe/Cd1-xZnxS core/shell quantum dots

Science.gov (United States)

Gheshlaghi, Negar; Pisheh, Hadi Sedaghat; Ünlü, Hilmi

2017-11-01

We investigated the effect of ternary shell alloy composition on the bandgap and diameter of core of ZnSe / Cd1 - x Znx S heterostructure core/shell quantum dots, which were synthesized by using a simple colloidal technique. Characterization by using the x-ray diffraction (XRD), transmission electron microscopy (TEM), UV-Vis absorption and fluorescence emission spectroscopic techniques indicate that (i) there is a transition of ZnSe / Cd0.6 Zn0.4 S Type-I heterostructure (electrons and holes tend to localize in core) to ZnSe / Cd0.75 Zn0.25 S quasi-Type-II heterostructures (holes tend to localized in the core and electrons are delocalized) and (ii) then after large red shift and Stock-shift in PL emission spectra but not a distinct absorption peak in UV spectra become noticeable in ZnSe/Cd0.75Zn0.25 S quasi-Type II and ZnSe/CdS Type II heterostructures (electrons are localized in core and holes are localized in shell). Furthermore, the increase of Cd:S ratio in shell alloy composition shifts the XRD peaks to lower 2θ degrees which corresponds to tensile strain in the ZnSe core. Finally, the hydrostatic interfacial strain has effect on the squeezing or stretching the capped core: A decrease of compressive force on core from ZnSe/ZnS to tensile force in ZnSe/CdS with increase in Cd:S ratio indicates that transition of compressive strain to tensile strain takes place with the transition from Type-I to II heterostructure.

Characteristics of mechanical alloying of Zn-Al-based alloys

International Nuclear Information System (INIS)

Zhu, Y.H.; Hong Kong Polytechnic; Perez Hernandez, A.; Lee, W.B.

2001-01-01

Three pure elemental powder mixtures of Zn-22%Al-18%Cu, Zn-5%Al-11%Cu, and Zn-27%Al-3%Cu (in wt.%) were mechanically alloyed by steel-ball milling processing. The mechanical alloying characteristics were investigated using X-ray diffraction, scanning electron microscopy, and transmission electron microscopy techniques. It was explored that mechanical alloying started with the formation of phases from pure elemental powders, and this was followed by mechanical milling-induced phase transformation. During mechanical alloying, phases stable at the higher temperatures formed at the near room temperature of milling. Nano-structure Zn-Al-based alloys were produced by mechanical alloying. (orig.)

Aqueous-phase synthesis and color-tuning of core/shell/shell inorganic nanocrystals consisting of ZnSe, (Cu, Mn)-doped ZnS, and ZnS

Energy Technology Data Exchange (ETDEWEB)

Choi, Jongwan; Yoon, Sujin [Department of Chemistry and Research Institute for Natural Science, Hanyang University, Seoul, 133-791 (Korea, Republic of); Kim, Felix Sunjoo, E-mail: fskim@cau.ac.kr [School of Chemical Engineering and Materials Science, Chung-Ang University, Seoul, 156-756 (Korea, Republic of); Kim, Nakjoong, E-mail: kimnj@hanyang.ac.kr [Department of Chemistry and Research Institute for Natural Science, Hanyang University, Seoul, 133-791 (Korea, Republic of)

2016-06-25

We report synthesis of colloidal nanocrystals based on ZnSe core, (Cu,Mn)-doped ZnS inner-shell, and ZnS outer-shell by using an eco-friendly method and their optical properties. Synthesis of core/shell/shell nanocrystals was performed by using a one-pot/three-step colloidal method with 3-mercaptopropionic acid as a stabilizer in aqueous phase at low temperature. A double-shell structure was employed with inner-shell as a host for doping and outer-shell as a passivation layer for covering surface defects. Copper and manganese were introduced as single- or co-dopants during inner-shell formation, providing an effective means to control the emission color of the nanocrystals. The synthesized nanocrystals showed fluorescent emission ranging from blue to green, to white, and to orange, adjusted by doping components, amounts, and ratios. The photoluminescence quantum yields of the core/doped-shell/shell nanocrystals approached 36%. - Highlights: • ZnSe/ZnS:(Cu,Ms)/ZnS core/(doped)shell/shell nanocrystals were synthesized in an aqueous phase. • Emission color of nanocrystals was controlled from blue to white to orange by adjusting the atomic ratio of Cu and Mn co-dopants. • Photoluminescence quantum yields of the colloidal nanocrystals approached 36%.

Effect of Zn(NO3)2 concentration in hydrothermal-electrochemical deposition on morphology and photoelectrochemical properties of ZnO nanorods

Science.gov (United States)

Yilmaz, Ceren; Unal, Ugur

2016-04-01

Zn(NO3)2 concentration had been reported to be significantly influential on electrodeposition of ZnO structures. In this work, this issue is revisited using hydrothermal-electrochemical deposition (HED). Seedless, cathodic electrochemical deposition of ZnO films is carried out on ITO electrode at 130 °C in a closed glass reactor with varying Zn(NO3)2 concentration. Regardless of the concentration of Zn2+ precursor (0.001-0.1 M) in the deposition solution, vertically aligned 1-D ZnO nanorods are obtained as opposed to electrodepositions at lower temperatures (70-80 °C). We also report the effects of high bath temperature and pressure on the photoelectrochemical properties of the ZnO films. Manipulation of precursor concentration in the deposition solution allows adjustment of the aspect ratio of the nanorods and the degree of texturation along the c-axis; hence photoinduced current density. HED is shown to provide a single step synthesis route to prepare ZnO rods with desired aspect ratio specific for the desired application just by controlling the precursor concentration.

Finite element analysis of surface acoustic waves in high aspect ratio electrodes

DEFF Research Database (Denmark)

Dühring, Maria Bayard; Laude, Vincent; Khelif, Abdelkrim

2008-01-01

This paper elaborates on how the finite element method is employed to model surface acoustic waves generated by high aspect ratio electrodes and their interaction with optical waves in a waveguide. With a periodic model it is shown that these electrodes act as a mechanical resonator which slows...

Composition-ratio influence on resistive switching behavior of solution-processed InGaZnO-based thin-film.

Science.gov (United States)

Hwang, Yeong-Hyeon; Hwang, Inchan; Cho, Won-Ju

2014-11-01

The influence of composition ratio on the bipolar resistive switching behavior of resistive switching memory devices based on amorphous indium-gallium-zinc-oxide (a-IGZO) using the spin-coating process was investigated. To study the stoichiometric effects of the a-IGZO films on device characteristics, four devices with In/Ga/Zn stoichiometries of 1:1:1, 3:1:1, 1:3:1, and 1:1:3 were fabricated and characterized. The 3:1:1 film showed an ohmic behavior and the 1:1:3 film showed a rectifying switching behavior. The current-voltage characteristics of the a-IGZO films with stoichiometries of 1:1:1 and 1:3:1, however, showed a bipolar resistive memory switching behavior. We found that the three-fold increase in the gallium content ratio reduces the reset voltage from -0.9 to - 0.4 V and enhances the current ratio of high to low resistive states from 0.7 x 10(1) to 3 x 10(1). Our results show that the increase in the Ga composition ratio in the a-IGZO-based ReRAM cells effectively improves the device performance and reliability by increasing the initial defect density in the a-IGZO films.

In-situ anion exchange fabrication of porous ZnO/ZnSe heterostructural microspheres with enhanced visible light photocatalytic activity

Energy Technology Data Exchange (ETDEWEB)

Liu, Hairui, E-mail: liuhairui1@126.com [College of Physics & Electrics Engineering, Henan Normal University, Henan Key Laboratory of Photovoltaic Materials, Xinxiang 453007 (China); Key Laboratory of Interface Science and Engineering in Advanced Materials (Taiyuan University of Technology), Ministry of Education, Taiyuan, Shanxi, 030024 (China); College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan, Shanxi 030024 (China); Hu, Yanchun [College of Physics & Electrics Engineering, Henan Normal University, Henan Key Laboratory of Photovoltaic Materials, Xinxiang 453007 (China); He, Xia [Key Laboratory of Interface Science and Engineering in Advanced Materials (Taiyuan University of Technology), Ministry of Education, Taiyuan, Shanxi, 030024 (China); Jia, Husheng, E-mail: jia_husheng@126.com [Key Laboratory of Interface Science and Engineering in Advanced Materials (Taiyuan University of Technology), Ministry of Education, Taiyuan, Shanxi, 030024 (China); College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan, Shanxi 030024 (China); Liu, Xuguang; Xu, Bingshe [Key Laboratory of Interface Science and Engineering in Advanced Materials (Taiyuan University of Technology), Ministry of Education, Taiyuan, Shanxi, 030024 (China)

2015-11-25

Porous ZnO microspheres were fabricated by an ultrasonic irradiation technique. Subsequently, through a facile in-situ anion exchange reaction between the ZnO microsphere and sodium selenite, spherical ZnO/ZnSe heterostructures with different ratios of the two components were fabricated. The as-obtained products were characterized by field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray (EDX) spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), and UV–vis spectrometry. The results reveal that the secondary ZnSe nanoparticles are grown on the surface of pre-grown ZnO microspheres. Compared with pure ZnO microspheres, the ZnO/ZnSe hetero-microspheres show enhance visible-light photocatalytic activity for degradation of methylene blue (MB) and 4-nitrophenol (4-NP). The enhanced photocatalytic performance is attributed to fast separation and transport of photogenerated electrons and holes derived from the coupling effect of ZnSe and ZnO heterostructure. Photoluminescent spectra further indicate that the ZnO/ZnSe heterostructures greatly suppress the charge recombination of photogenerated electron–hole pairs, which would be beneficial to improve their photocatalytic activity. Finally, the photocatalytic mechanism of the ZnO/ZnSe heterostructures is proposed. - Graphical abstract: Porous ZnO/ZnSe heterostructures with different ratios of the two components were fabricated and present enhance visible-light photocatalytic activity for degradation of methylene blue (MB) and 4-nitrophenol (4-NP). The enhanced photocatalytic performance is attributed to fast separation and transport of photogenerated electrons and holes derived from the coupling effect of ZnSe and ZnO heterostructure. - Highlights: • Spherical ZnO/ZnSe porous composites were fabricated by in-situ anion exchange. • ZnO/ZnSe composites exhibited enhanced visible-light photocatalytic activity. • The matching band gap improves the separation of

Determinação dos elementos-traço (Zn, Co e Ni em sedimentos da Plataforma Continental Amazônica sob influência da descarga do rio Amazonas Determination of trace elements (Zn, Co and Ni in sediments at the Amazon Continental Shelf on influence of the Amazon River discharge

Directory of Open Access Journals (Sweden)

Gilmar Wanzeller Siqueira

2006-01-01

Full Text Available Esta pesquisa foi desenvolvida na Plataforma Continental Amazônica (PCA no trecho compreendido entre os cabos Orange (AP e Maguari (PA, para determinar os teores de Zn, Co e Ni nos sedimentos superficiais, identificando o papel dos sedimentos como fonte ou reserva de elementos-traço. A concentração dos elementos metálicos apresentou a seguinte associação: Zn > Ni > Co. Os sedimentos localizados na PCA podem ser considerados como sítio de ocorrência natural dos elementos metálicos, não havendo influência de fontes poluidoras na liberação destes para o sistema.Determination of trace elements (Zn, Co and Ni in sediments at the Amazon Continental Shelf on influence of the Amazon River discharge This research was developed at Amazon Continental Shelf (ACS between the Orange Cape (Amapá State and the Maguari Cape (Pará State, to determine the levels of zinc, cobalt and nickel in the superficial sediments identifying its inputs and outputs. The rate of these metallic elements in the sediments decreases following Zn> Ni> Co. The concentrations of total metals in the surface sediments range from Zn = 52.8 159.5; Ni = 21.7 47.4 and Co = 14.3 48.8 (mg.kg-1. The levels of trace elements observed in the sediments at ACS are of natural occurrence. Pollution sources of metallic elements were not observed.

K X-ray production cross sections, Kβ/Kα ratios, and radiative Auger ratios for protons impacting low-Z elements

International Nuclear Information System (INIS)

Cipolla, Sam J.

1999-01-01

A Cockcroft-Walton accelerator was used to produce 50-300 keV protons to excite characteristic X-rays from thick targets of elements from Z=21 to 32, using an efficiency-calibrated Si(Li) detector equipped with an ultra-thin window. X-ray production cross sections were determined and compared with prevailing theories. Special attention was paid to accounting for the radiative Auger effects (RAE) in the analysis of the X-ray energy spectra. Ratios of RAE to K α and K β intensities, as well as K β /K α ratios, will be compared to theoretical values

Element distribution study of drinking water and well sediments using the method of instrumental neutron activation analysis

International Nuclear Information System (INIS)

Vircavs, M.; Taure, I.; Eglite, G.; Brike, Z.

1996-01-01

The method of instrumental activation analysis was used to estimate the distribution of major, minor and trace elements in well sediments, Riga tap water and well water used for drinking and for preparation of food. The chemical composition of drinking water (tap and well water) varies considerably in different districts of Riga and in different wells. The greatest concentration differences for Zn, Fe and Al are observed in tap water. Median concentrations of determined elements are smaller than maximum permissible concentrations (MPC). However, in some cases the concentration of Al and Fe higher than their MPC for tap water. The highest concentration ratios were observed for Ti, Cr and Zn in well sediments. (author). 19 refs, 2 tabs

Selected element contents formation in linseed plants (Linum usitatissimum L. depending on the phase of development and plant part

Directory of Open Access Journals (Sweden)

Tadeusz Zając

2013-12-01

Full Text Available A single factor (variety strict field experiment was carried out in 1999-2000 at the experimental station of the Department of Plant Production, Agricultural University of Krakow located at Prusy near Cracow to study the changes in selected macro-and microelement concentrations in the top parts of linseed and the uptake of these elements during vegetation at the characteristic phases of development, including also the plant parts, i.e. leaves, stems, seeds and straw. On the basis of obtained results it was demonstrated that microelement contents in the linseed top parts changed considerably with the plant growth. The levels of Cr, Zn,Cd, Fe and Mn were highest at budding, while Cr, Pb, Fe and Mn levels were lowest at full maturity phase. Linseed grown in the area unpolluted with trace elements did not reveal the ability to accumulate excessive amounts of Cr, Zn, Pb, Cu, Ni, Fe and Mn, undesired from the usefulness for consumption point of view. Cadmium, irrespective of the examined stage of plant development, revealed high capacity for an excessive accumulation in the top parts. The contents and reciprocal ratios of macroelements in plants changed variously with their growth. The highest Na and K contents were noticed at budding phase, Ca at vegetative stage (arborescent and Mg at the initial budding. The widest Ca:P ratio and K:(Ca+Mg ratio occurred at budding, whereas K:Na ratio at full maturity phase. Linseed accumulated macro- and microele ments in the yield at various rates. Among the analysed elements Cd, Zn and Ni were taken up proportionally to increasing yields of linseed top part biomass.

Direct evidence for As as a Zn-site impurity in ZnO

CERN Document Server

Wahl, Ulrich; Correia, J G; Lourenço-Santana-Marques, Ana Claudia; Alves, E; Carvalho-Soares, José

2005-01-01

Arsenic has been reported in the literature as one of the few p-type dopants in the technologically promising II-VI semiconductor ZnO. However, there is an ongoing debate whether the p-type character is due to As simply replacing O atoms or to the formation of more complicated defect complexes, possibly involving As on Zn sites. We have determined the lattice location of implanted As in ZnO by means of conversion electron emission channeling from radioactive $^{73}$As. In contrast to what one might expect from its nature as a group V element, we find that As does not occupy substitutional O sites but in its large majority substitutional Zn sites. Arsenic in ZnO (and probably also in GaN) is thus an interesting example for an impurity in a semiconductor where the major impurity lattice site is determined by atomic size and electronegativity rather than its position in the periodic system.

Synthesis and characterization of Mn-doped ZnO column arrays

International Nuclear Information System (INIS)

Yang Mei; Guo Zhixing; Qiu Kehui; Long Jianping; Yin Guangfu; Guan Denggao; Liu Sutian; Zhou Shijie

2010-01-01

Mn-doped ZnO column arrays were successfully synthesized by conventional sol-gel process. Effect of Mn/Zn atomic ratio and reaction time were investigated, and the morphology, tropism and optical properties of Mn-doped ZnO column arrays were characterized by SEM, XRD and photoluminescence (PL) spectroscopy. The result shows that a Mn/Zn atomic ratio of 0.1 and growth time of 12 h are the optimal condition for the preparation of densely distributed ZnO column arrays. XRD analysis shows that Mn-doped ZnO column arrays are highly c-axis oriented. As for Mn-doped ZnO column arrays, obvious increase of photoluminescence intensity is observed at the wavelength of ∼395 nm and ∼413 nm, compared to pure ZnO column arrays.

The elements Se, Hg, Cr, Sb, Fe, Zn, Co, and Rb were investigated by neutron activation analysis in blood serum of leukemia patients and workers of metal coating industries

International Nuclear Information System (INIS)

Taheriean, Ali Akbar.

1992-02-01

Current universal interests in trace element studies are being spurred by our needs to determine trace element requirements and tolerance by organism, including relationships to animal and human health and disease, evaluate the potential bio magnification and bio toxicity of trace elements. The element Se, Hg, Cr, Sb, Fe, Zn, Co, and Rb were investigated in blood serum of 24 leukemia patients and 20 workers of metal coating of industries, using neutron activation analysis and gamma ray counting high purity germanium detector, it was possible to determine the above mentioned trace elements with great accuracy. The result of these investigations are described briefly. In the blood serum of leukemia patients, which were collected from Ali Asghar children Hospital, some increase of Fe and decrease of Se could be found, whereas the amount variation of other trace elements were negligible. The amount of Zn in the blood serum of these workers by comparison with 60 normal man indicates no change. Due to importance of trace elements in the human health we suggest that this investigation must be prolonged using more samples

Preparation of Cu2ZnSnS4 nano-crystalline powder by mechano-chemical method

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Alirezazadeh, Farzaneh; Sheibani, Saeed; Rashchi, Fereshteh

2018-01-01

Copper zinc tin sulfide (Cu2ZnSnS4, CZTS) is one of the most promising ceramic materials as an absorber layer in solar cells due to its suitable band gap, high absorption coefficient and non-toxic and environmental friendly constituent elements. In this work, nano-crystalline CZTS powder was synthesized by mechanical milling. Elemental powders of Cu, Zn, Sn and were mixed in atomic ratio of 2:1:1:4 according to the stoichiometry of Cu2ZnSnS4 and then milled in a planetary high energy ball mill under argon atmosphere. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and diffusion reflectance spectroscopy (DRS). XRD results confirm the formation of single-phase CZTS with kesterite structure after 20 h of milling. Also, the mean crystallite size was about 35 nm. SEM results show that after 20 h of milling, the product has a relatively uniform particle size distribution. Optical properties of the product indicate that the band gap of prepared CZTS is 1.6 eV which is near to the optimum value for photovoltaic solar cells showing as a light absorber material in solar energy applications.

A volatile topic: Parsing out the details of Earth's formation through experimental metal-silicate partitioning of volatile and moderately volatile elements

Science.gov (United States)

Mahan, B. M.; Siebert, J.; Blanchard, I.; Badro, J.; Sossi, P.; Moynier, F.

2017-12-01

Volatile and moderately volatile elements display different volatilities and siderophilities, as well as varying sensitivity to thermodynamic controls (X, P, T, fO2) during metal-silicate differentiation. The experimental determination of the metal-silicate partitioning of these elements permits us to evaluate processes controlling the distribution of these elements in Earth. In this work, we have combined metal-silicate partitioning data and results for S, Sn, Zn and Cu, and input these characterizations into Earth formation models. Model parameters such as source material, timing of volatile delivery, fO2 path, and degree of impactor equilibration were varied to encompass an array of possible formation scenarios. These models were then assessed to discern plausible sets of conditions that can produce current observed element-to-element ratios (e.g. S/Zn) in the Earth's present-day mantle, while also satisfying current estimates on the S content of the core, at no more than 2 wt%. The results of our models indicate two modes of accretion that can maintain chondritic element-to-element ratios for the bulk Earth and can arrive at present-day mantle abundances of these elements. The first mode requires the late addition of Earth's entire inventory of these elements (assuming a CI-chondritic composition) and late-stage accretion that is marked by partial equilibration of large impactors. The second, possibly more intuitive mode, requires that Earth accreted - at least initially - from volatile poor material preferentially depleted in S relative to Sn, Zn, and Cu. From a chemical standpoint, this source material is most similar to type I chondrule rich (and S poor) materials (Hewins and Herzberg, 1996; Mahan et al., 2017; Amsellem et al., 2017), such as the metal-bearing carbonaceous chondrites.

Brain regional distributions of the minor and trace elements, Na, Mg, Cl, K, Mn, Zn, Rb and Br, in young and aged mice

International Nuclear Information System (INIS)

Amano, R.; Oishi, S.; Ishie, M.; Kimura, M.

2001-01-01

Brain regional cerebral concentrations of minor and trace elements, Na, Mg, Cl, K, Mn, Zn, Rb and Br were determined in young and aged mice, by instrumental neutron activation analysis for small amounts of regional (corpus striatum, cerebellum, cerebral cortex, hippocampus, midbrain, pons and medulla olfactory bulb) samples. Significant age-related differences were found for Mn concentration in all brain regions: The Mn concentration of the young brain was higher than those of aged brain, in addition, Zn was distributed heterogeneously, and highly concentrated in cerebral cortex and hippocampus regions in both young and aged mice. These results suggest that, in the aged brain, Mn is required less than in the young brain, on the other hand, Zn is required equally in both young and aged brains. (author)

Ionization ratios and elemental abundances in the atmosphere of 68 Tauri

Science.gov (United States)

Aouina, A.; Monier, R.

2017-12-01

We have derived the ionization ratios of twelve elements in the atmosphere of the star 68 Tauri (HD 27962) using an ATLAS9 model atmosphere with 72 layers computed for the effective temperature and surface gravity of the star. We then computed a grid of synthetic spectra generated by SYNSPEC49 based on an ATLAS9 model atmosphere in order to model one high resolution spectrum secured by one of us (RM) with the échelle spectrograph SOPHIE at Observatoire de Haute Provence. We could determine the abundances of several elements in their dominant ionization stage, including those defining the Am phenomenon. We thus provide new abundance determinations for 68 Tauri using updated accurate atomic data retrieved from the NIST database which extend previous abundance works.

Intrinsic labeling of alpha-fetoprotein with 65Zn

International Nuclear Information System (INIS)

Preiss, I.L.

1994-01-01

Many enzymes, proteins, and large molecules bind a variety of inorganic ions. The replacement of a specific metal ion with another element can disrupt the biodistribution and biochemistry of the host molecule. Alpha-fetoprotein (AFP) is a known oncofetal antigen. The authors have demonstrated that the substitution of Cu or Pb on AFP inhibits the transplacental migration of AFP and may lead to fetal demise. It is evident that in labeling with a radiotracer in order to observe the true distribution of a molecule, one must select a radioisotope of an element which is naturally bound to the host molecule. It has been demonstrated that AFP binds Zn in vivo. Thus, substituting 65 Zn for natural Zn produces an intrinsic label for AFP. The authors discuss the methodology for stripping and labeling of AFP with 65 Zn. The biodistribution of labeled AFP is compared with that of 65 Zn 2+ in healthy and diseased (hepatoma) animals

Luminescence properties of In(Zn)P alloy core/ZnS shell quantum dots

Science.gov (United States)

Thuy, Ung Thi Dieu; Reiss, Peter; Liem, Nguyen Quang

2010-11-01

Chemically synthesized InP/ZnS core/shell quantum dots (QDs) are studied using time-resolved photoluminescence spectroscopy and x-ray diffraction. Zinc stearate, which is added during the synthesis of the InP core, significantly improves the optical characteristics of the QDs. The luminescence quantum yield (QY) reaches 60%-70% and the emission is tunable from 485 to 586 nm by varying the Zn2+:In3+ molar ratio and growth temperature. The observed increased Stokes shift, luminescence decay time, and QY in the presence of Zn are rationalized by the formation of an In(Zn)P alloy structure that causes band-edge fluctuation to enhance the confinement of the excited carriers.

Phytoextraction of potentially toxic elements by Indian mustard, rapeseed, and sunflower from a contaminated riparian soil.

Science.gov (United States)

Shaheen, Sabry M; Rinklebe, Jörg

2015-12-01

The objective of this study was to quantify the phytoextraction of the potentially toxic elements Al, As, Cd, Co, Cr, Cu, Mo, Ni, Pb, Se, V, and Zn by Indian mustard, rapeseed, and sunflower from a contaminated riparian soil. To achieve this goal, a greenhouse pot experiment was established using a highly contaminated grassland soil collected at the Wupper River (Germany). The impact of ethylene-diamine-tetra-acetic acid (EDTA), humate (HK), and phosphate potassium (PK) on the mobility and uptake of the elements by rapeseed also was investigated. Indian mustard showed the highest efficiency for phytoextraction of Al, Cr, Mo, Se, and V; sunflower for Cd, Ni, Pb, and Zn, and rapeseed for Cu. The bioconcentration ratios were higher than 1 for the elements (except As and Cu), indicating the suitability of the studied plants for phytoextraction. Application of EDTA to the soil increased significantly the solubility of Cd, Co, Cr, Ni, and Pb and decreased the solubility of Al, As, Se, V, and Mo. Humate potassium decreased significantly the concentrations of Al and As in rapeseed but increased the concentrations of Cu, Se, and Zn. We may conclude that HK can be used for immobilization of Al and As, while it can be used for enhancing the phytoextraction of Cu, Se, and Zn by rapeseed. Phosphate potassium immobilized Al, Cd, Pb, and Zn, but enhanced phytoextraction of As, Cr, Mo, and Se by rapeseed.

PM2.5 particulates and metallic elements (Ni, Cu, Zn, Cd and Pb) study in a mixed area of summer season in Shalu, Taiwan.

Science.gov (United States)

Fang, Guor-Cheng; Xiao, You-Fu; Zhuang, Yuan-Jie; Cho, Meng-Hsien; Huang, Chao-Yang; Tsai, Kai-Hsiang

2017-08-01

PM 2.5 has become an important environmental issue in Taiwan during the past few years. Moreover, electricity increased significantly during the summertime and TTPP generated by coal burning base is the main electricity provider in central Taiwan. Therefore, summer season has become the main research target in this study. The ambient air concentrations of particulate matter PM 2.5 and PM 10 collected by using VAPS at a mixed characteristic sampling site were studied in central Taiwan. The results indicated that the average daytime PM 2.5 and PM 10 particulate concentrations were occurred in May and they were 44.75 and 57.77 µg/m 3 in this study. The results also indicated that the average nighttime PM 2.5 and PM 10 particulate concentrations were occurred in June and they were 38.19 and 45.79 µg/m 3 in this study. The average PM 2.5 /PM 10 ratios were 0.7 for daytime, nighttime and 24-h sampling periods in the summer for this study. This value was ranked as the lowest ratios when compared to the other seasons in previous study. Noteworthy, the results further indicated that the metallic element Pb has the mean highest concentrations for 24-h, daytime and nighttime sampling periods when compared to those of the other metallic elements (Ni, Cu, Zn and Cd). The average mean highest metallic Pb concentrations in PM10 were 110.7, 203.0 and 207.2 ng/m 3 for 24-h, daytime and nighttime sampling periods in this study. And there were 59.53, 105.2 and 106.6 ng/m 3 for Pb in PM2.5 for 24-h, daytime and nighttime sampling periods, respectively. Moreover, the results further indicated that mean metallic element Pb concentrations on PM 2.5 and PM 10 were all higher than those of the other elements for 24 h, day and nighttime.

Uptake of elements by fungi in the Forsmark area

Energy Technology Data Exchange (ETDEWEB)

Johanson, Karl J.; Nikolova, Ivanka; Taylor, Andy F.S. [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Forest Mycology and Pathology; Vinichuk, Mykhaylo M. [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Soil Sciences

2004-10-01

Samples were collected in a forest ecosystem close to the Nuclear Power Plant at Forsmark, Sweden. The soil was fractioned in bulk soil, rhizosphere, soil-root interface and fungal mycelium. At the same sampling sites, fruit bodies of fungi were also collected. The concentration (mg/kg dw of soil) of K, Rb, Cs, P, Ca, Cr, Mn, Co, Ni, Cu, Zn, As, Sr, Cd, I, Hg, Pb, Ra, Th and U, were analysed in the various fractions using microspectrometry. The concentration of the stable potassium, rubidium and cesium in forest soil as well as in fungal compartment is discussed first and than the other 17 elements is discussed. Compared to bulk soil, rhizosphere was enriched with K, Rb and Cs by a factor 1.3, 1.7 and 1.5, and soil-root interface by factor 5.4, 2.6 and 1.0. Concentration of K, Rb and Cs was much higher in mycelium compared to bulk soil, indicating accumulation of these elements within fungi. The concentration ratios (CR) defined as mg/kg dw in mycelium divided by mg/kg dw in soil were found to be 4.5, 5.1 and 2.4 for K, Rb and Cs respectively. For fruit bodies of fungi, these ratios were about one order of magnitude higher than that for mycelium: 65, 3. 75.8 and 18.6 for K, Rb and Cs, respectively. In mycelium, only weak correlations were found between K and Rb uptake (r=0.33) and between K and Cs uptake (r=0.48). The concentrations of the elements in fruit bodies of fungi were species-dependent. Generally, fungi seemed to take up Rb more efficiently than K. Highest Cs concentrations were found in fruit bodies of Sarcodon imbricatus (25.1 mg/kg). Sarcodon imbricatus was found to accumulate K, Cs and especially Rb to greatest extent, followed by Cortinarius sp., and Suillus variegatus. Litter decomposing fungi Hypholoma capnoides and Collybia peronata showed relatively weak ability to accumulate K, Rb as well as Cs, compared to the mycorrhizal species. No correlation was found between concentration of K, Rb and Cs in fruit bodies of fungi and soil pH as well as

Uptake of elements by fungi in the Forsmark area

International Nuclear Information System (INIS)

Johanson, Karl J.; Nikolova, Ivanka; Taylor, Andy F.S.; Vinichuk, Mykhaylo M.

2004-10-01

Samples were collected in a forest ecosystem close to the Nuclear Power Plant at Forsmark, Sweden. The soil was fractioned in bulk soil, rhizosphere, soil-root interface and fungal mycelium. At the same sampling sites, fruit bodies of fungi were also collected. The concentration (mg/kg dw of soil) of K, Rb, Cs, P, Ca, Cr, Mn, Co, Ni, Cu, Zn, As, Sr, Cd, I, Hg, Pb, Ra, Th and U, were analysed in the various fractions using microspectrometry. The concentration of the stable potassium, rubidium and cesium in forest soil as well as in fungal compartment is discussed first and than the other 17 elements is discussed. Compared to bulk soil, rhizosphere was enriched with K, Rb and Cs by a factor 1.3, 1.7 and 1.5, and soil-root interface by factor 5.4, 2.6 and 1.0. Concentration of K, Rb and Cs was much higher in mycelium compared to bulk soil, indicating accumulation of these elements within fungi. The concentration ratios (CR) defined as mg/kg dw in mycelium divided by mg/kg dw in soil were found to be 4.5, 5.1 and 2.4 for K, Rb and Cs respectively. For fruit bodies of fungi, these ratios were about one order of magnitude higher than that for mycelium: 65, 3. 75.8 and 18.6 for K, Rb and Cs, respectively. In mycelium, only weak correlations were found between K and Rb uptake (r=0.33) and between K and Cs uptake (r=0.48). The concentrations of the elements in fruit bodies of fungi were species-dependent. Generally, fungi seemed to take up Rb more efficiently than K. Highest Cs concentrations were found in fruit bodies of Sarcodon imbricatus (25.1 mg/kg). Sarcodon imbricatus was found to accumulate K, Cs and especially Rb to greatest extent, followed by Cortinarius sp., and Suillus variegatus. Litter decomposing fungi Hypholoma capnoides and Collybia peronata showed relatively weak ability to accumulate K, Rb as well as Cs, compared to the mycorrhizal species. No correlation was found between concentration of K, Rb and Cs in fruit bodies of fungi and soil pH as well as

Trace element analysis of soy sauce

International Nuclear Information System (INIS)

Tomita, Michio; Haruyama, Yoichi; Saito, Manabu

1994-01-01

Trace elements in soy sauce have been measured by means of in-air PIXE. Six kinds of trace elements were detected, such as Mu, Fe, Ni, Zn, Cu and Br. Concentrations of Mn, Fe, Zn and Br which were observed in all samples, have been determined. Each analyzed sample contained considerable amount of bromine about 160 ppm. (author)

Brain trace elements and aging

International Nuclear Information System (INIS)

Hebbrecht, Geert; Maenhaut, Willy; Reuck, Jacques de

1999-01-01

Degenerative mechanisms involved in the aging process of the brain are to a certain extent counteracted by repair mechanisms. In both degenerative and recovery processes, trace elements are involved. The present study focused on the role of two minor (i.e., K and Ca) and six trace elements (i.e., Mn, Fe, Cu, Zn, Se and Rb) in the aging process. The elements were determined by PIXE in cerebral cortex and white matter, basal ganglia, brainstem and cerebellar cortex of 18 postmortem human brains, from persons without a history of neurologic or psychiatric disease who deceased between the age of 7 and 79. This age range allowed us to study the relationship between elemental concentrations and age. The most prominent findings were a concentration decrease for K and Rb and a concentration increase for the elements Ca, Fe, Zn and Se. The study supports recent findings that Ca and Fe are involved in brain degenerative processes initiated by oxygen free radicals, whereas Zn and Se are involved in immunological reactions counteracting the aging process

The new barium zinc mercurides Ba3ZnHg10 and BaZn0.6Hg3.4 – Synthesis, crystal and electronic structure

International Nuclear Information System (INIS)

Schwarz, Michael; Wendorff, Marco; Röhr, Caroline

2012-01-01

The title compounds Ba 3 ZnHg 10 and BaZn 0.6 Hg 3.4 were synthesized from stoichiometric ratios of the elements in Ta crucibles. Their crystal structures, which both represent new structure types, have been determined using single crystal X-ray data. The structure of Ba 3 ZnHg 10 (orthorhombic, oP28, space group Pmmn, a=701.2(3), b=1706.9(8), c=627.3(3)pm, Z=2, R1=0.0657) contains folded 4 4 Hg nets, where the meshes form the bases of flat rectangular pyramids resembling the structure of BaAl 4 . The flat pyramids are connected via Hg–Zn/Hg bonds, leaving large channels at the folds, in which Ba(1) and Hg(2) atoms alternate. Whereas the remaining Hg/Zn atoms form a covalent 3D network of three- to five-bonded atoms with short M–M distances (273–301 pm; CN 9–11), the Hg(2) atoms in the channels adopt a comparatively large coordination number of 12 and increased distances (317–348 pm) to their Zn/Hg neighbours. In the structure of BaZn 0.6 Hg 3.4 (cubic, cI320, space group I4 ¯ 3d, a=2025.50(7) pm, Z=64, R1=0.0440), with a chemical composition not much different from that of Ba 3 ZnHg 10 , the Zn/Hg atoms of the mixed positions M(1/2) are arranged in an slightly distorted primitive cubic lattice with a 4×4×4 subcell relation to the unit cell. The 24 of the originating 64 cubes contain planar cis tetramers Hg(5,6) 4 with Hg in a nearly trigonal planar or tetrahedral coordination. In another 24 of the small cubes, two opposing faces are decorated by Hg(3,4) 2 dumbbells, two by Ba(2) atoms respectively. The third type of small cubes are centered by Ba(1) atoms only. The complex 3D polyanionic Hg/Zn network thus formed is compared with the Hg partial structure in Rb 3 Hg 20 applying a group-subgroup relation. Despite their different overall structures, the connectivity of the negatively charged Hg atoms, the rather metallic Zn bonding characteristic (as obtained from FP-LAPW band structure calculations) and the coordination number of 16 for all Ba cations

Availability of essential trace elements in medicinal herbs used for diabetes mellitus and their possible correlations

International Nuclear Information System (INIS)

Choudhury, R.P.; Garg, A.N.; Acharya, R.; Nair, A.G.C.; Reddy, A.V.R.

2008-01-01

Four plant parts (leaves, roots, fruits and seeds) of twenty samples of sixteen antidiabetic herbs including three commercially marketed capsules have been analyzed for 6 minor (Na, K, Ca, Cl, Mg, and P) and 21 trace (As, Ba, Br, Ce, Co, Cr, Cs, Cu, Eu, Fe, Hg, La, Mn, Rb, Sb, Sc, Se, Sm, Th, V and Zn) elements by instrumental neutron activation analysis (INAA). Further, Ni, Cd and Pb contents were determined by AAS. Elemental data were validated by simultaneously analyzing reference material (RM), MPH-2 Mixed Polish Herbs. Several elements such as Cr and V (1-2 μg/g), Rb (10-40 μg/g), Cs (80-300 ng/g), Se (∼100 ng/g) and Zn (25-60 μg/g) play an important role in diabetes mellitus. Interelemental linear correlations have been observed for Cu vs. Zn (r = 0.89) and Rb vs. Cs (r 0.87). K/P ratio varies in a narrow range with a mean value of 6.2±1.4. Toxic elements As and Hg were found in <1 μg/g whereas Cd and Pb were in ∼5 μg/g and <10 μg/g, respectively. (author)

Trace elements in natural drugs determined by INAA

International Nuclear Information System (INIS)

Chen Kehshaw; Tseng Chialiang; Lin Tehsien

1993-01-01

Natural drugs are widely used for diuretic, phlegm elimination and stomach invigoration purposes. Seventy-five of the most common remedies used by Chinese people have been subjected to trace element survey analysis by instrumental neutron activation. Within this large number of different natural products, fourteen trace elements (K, Sc, Cr, Fe, Co, Zn, Br, Rb, Cs, La, Sm, Eu, Au and Th) are commonly detected. Among these elements, Fe had the highest concentration followed by Zn, and Rb, Sm, Eu and Au were found to have the lowest concentrations. Although the three groups of natural drugs exhibit a widely different therapeutic action, the concentration ranges of the fourteen elements were very similar. While this suggests no apparent specific role for the trace elements in the drug function, parallels are drawn between the known drug related functions of Rb, Zn, Br, Fe, Co and K and the levels of elements found in the natural drugs. It is concluded that the various natural drugs also provide human benefits through supplements of essential elements such as Fe, Zn, Cr, Sc, Rb and Co. (author) 13 refs.; 5 tabs

Zinc and group V element co-implantation in indium phosphide

International Nuclear Information System (INIS)

Yu, Kin Man; Ridgway, M.C.

2000-01-01

Group V elements with mass ranging from 35 to 122 amu have been co-implanted with Zn in InP substrates. Co-implantation with all group V elements drastically reduced Zn out-diffusion and to a certain extent also inhibited Zn in-diffusion. The reduction in out-diffusion was insensitive to the group V element mass and thus, to implantation-induced damage. We believe the group V element excess created an In-vacancy excess that enhanced Zn substitution into the In sublattice. A maximum hole concentration of 7x10 18 cm -3 was achieved with P co-implantation. Electrochemical capacitance-voltage profiling clearly showed a decrease in hole concentration as a function of increasing group V element mass. This was attributed to differences in compensating residual implantation-induced damage

Anthropogenic impacts in North Poland over the last 1300 years - A record of Pb, Zn, Cu, Ni and S in an ombrotrophic peat bog

International Nuclear Information System (INIS)

De Vleeschouwer, Francois; Fagel, Nathalie; Cheburkin, Andriy; Pazdur, Anna; Sikorski, Jaroslaw; Mattielli, Nadine; Renson, Virginie; Fialkiewicz, Barbara; Piotrowska, Natalia; Le Roux, Gael

2009-01-01

Lead pollution history over Northern Poland was reconstructed for the last ca. 1300 years using the elemental and Pb isotope geochemistry of a dated Polish peat bog. The data show that Polish Pb-Zn ores and coal were the main sources of Pb, other heavy metals and S over Northern Poland up until the industrial revolution. After review of the potential mobility of each element, most of the historical interpretation was based on Pb and Pb isotopes, the other chemical elements (Zn, Cu, Ni, S) being considered secondary indicators of pollution. During the last century, leaded gasoline also contributed to anthropogenic Pb pollution over Poland. Coal and Pb-Zn ores, however, remained important sources of pollution in Eastern European countries during the last 50 years, as demonstrated by a high 206 Pb/ 207 Pb ratio (1.153) relative to that of Western Europe (ca. 1.10). The Pb data for the last century were also in good agreement with modelled Pb inventories over Poland and the Baltic region.

Comparative study on structure, corrosion properties and tribological behavior of pure Zn and different Zn-Ni alloy coatings

Energy Technology Data Exchange (ETDEWEB)

Tafreshi, M. [Department of Metallurgy and Materials Engineering, South Tehran Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Allahkaram, S.R., E-mail: akaram@ut.ac.ir [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, P.O.Box: 11155-4563, Tehran (Iran, Islamic Republic of); Farhangi, H. [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, P.O.Box: 11155-4563, Tehran (Iran, Islamic Republic of)

2016-11-01

Zn and Zn-Ni alloy coatings were electrodeposited from sulfate based electrolytes. The effect of alloys Ni content on morphology, microstructure, corrosion properties, microhardness and tribological behavior of these coatings were investigated and the results were compared with Zn film. According to X-ray diffraction patterns, different intermediate phases (η-Ni{sub 3}Zn{sub 22}, γ-Ni{sub 5}Zn{sub 21}, β-Zn-Ni) were formed by increasing the coatings Ni content from 11 to 17 wt%. Polarization and EIS results revealed that all the alloy coatings had better corrosion resistance than the Zn film. Zn-14 wt%Ni coating had the least corrosion current density and maximum polarization resistance between all the samples. Microhardness of the coatings was improved by increasing their Ni percentage to 17%. However, Zn-14 wt%Ni coating had the lowest wear loss and friction coefficient, while Zn film had the worst wear resistance between all the coatings. - Highlights: • Effect of Ni alloying element on morphology and structure of Zn electrodeposits. • Comparing corrosion behavior of Zn and Zn-Ni coatings. • Influence of Ni content on hardness of Zn-Ni films. • A comparison of tribological behavior of Zn and different Zn-Ni electrodeposits.

Investigation on the trace elemental profile of sewage workers in Kolkata, an Indian megacity

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Rajlaxmi Basu

2015-07-01

Full Text Available Background. Environmental pollution has become a global health risk. Exposure to pollutants at the work place, i.e. occupational exposure, is one of the areas that need immediate attention. The civic drainage workers are exposed to pollutants present in the wastewater they handle and most of them are toxic heavy metals. Exposure to such pollutants may be a health hazard, since it can lead to the imbalance in nutrient elements status.§Design and Methods. In the present study, profiling of trace elements in the blood of drainage worker population from an Indian megacity, Kolkata, was carried out by energy dispersive x-ray fluorescence (EDXRF and compared with the control group population of the same area. Results. The elements detected by EDXRF spectrometry include P, S, Cl, K, Fe, Cu, Zn, Se, Br, and Rb. By using ANOVA with 5% significance level, we observed significant alterations in the trace elements status, iron over loading, selenium deficiency, and in Cu-Zn ratio. Gender specific variations within the same population were also observed. Conclusions. The results indicate that the drainage workers have altered elemental profile in comparison to that of control population.

Inductively coupled plasma-mass spectrometry for elemental analysis and isotope ratio determinations in individual organic compounds separated by gas chromatography

International Nuclear Information System (INIS)

Chong, N.S.; Houk, R.S.

1987-01-01

A gas chromatograph (GC) with a packed column was interfaced to an inductively coupled plasma-mass spectrometer (ICP-MS) to yield atomic mass spectra from volatile organic compounds. Atomization of injected compounds was nearly complete and independent of molecular structure, so that elemental ratios could be determined. Detection limits were in the range 0.001 to 400 ng s -1 , depending on the ionization energy of the element and its abundance in the background spectrum. The relative standard deviation of measured isotope ratios varied from 0.4% for Br (i.e., a ratio close to unity) to 18% for N (a very large ratio). Thus, GC-ICP-MS provides elemental and isotope ratio information that is complementary to the molecular information derived from GC-MS with conventional ionization methods

Elemental composition of otoliths from migrating chum salmon, Oncorhynchus keta, captured at the Kitakami river and Ishinomaki Bay

International Nuclear Information System (INIS)

Kakuta, Izuru; Iizuka, Keiki; Sugawara, Yoshio; Tsuchiya, Takeshi; Ishii, Keizo

2000-01-01

The elemental composition (Ca, Sr, Zn and Fe) of otoliths from migrating chum salmon, Oncorhynchus keta, captured at the Kitakami river and Ishinomaki Bay was analyzed to understand the migratory history using a particle induced X-ray emission (PIXE) technique. The Sr/Ca ratio of salmon otoliths was lower (less than 1 x 10 -3 ) in the portion formed in a freshwater environment and higher (approximately 4.8 x 10 -3 ) in a sea water environment. When the fish migrated from sea water into a freshwater environment, the otoliths' Sr/Ca ratios significantly increased. The highest values were found in the fish captured at the lower part of the Kitakami river (about 20 km upriver from the mouth). The values from the fish captured at the upper part of the Kitakami river (about 200 km upriver from the mouth) were also not less than those of the fish captured at Ishinomaki Bay. Abnormally high otolith Sr/Ca ratios for these upriver-migrating fish, when compared to the values from non-migrating salmon inhabiting stable environmental (salinity and temperature) conditions, provided evidence that they were stressed. No significant changes in the otoliths' Zn/Ca ratios were found, while these values were inversely proportional to the Sr/Ca ratios. However, a rapid drop in the Zn/Ca ratio and an increase in the Sr/Ca ratio was observed in some individuals in which higher values for the Fe/Ca were found. These results suggest that these otolith parameters don't exactly reflect the salinity and temperature history in upriver-migrating chum salmon because the physiological mechanism of incorporation of Sr, Zn and Ca within the otolith of those fish is abnormal, though for fish in non-stressful conditions the Sr/Ca and the Zn/Ca ratios in otoliths are effective indices for predicting the history of environmental conditions experienced by the fish in the past. Regarding the relationship between the Sr/Ca and the Zn/Ca ratios, and also the Fe/Ca ratio, there is a possibility that they

Stratospheric particles: Synchrotron x-ray fluorescence determination of trace element contents

International Nuclear Information System (INIS)

Sutton, S.R.; Flynn, G.J.

1987-01-01

The first trace element analyses on stratospheric particles using synchrotron x-ray fluorescence (SXRF) are reported. Cr, Mn, Fe, Ni, Cu, Zn, Ga, Ge, Se and Br were detected. Concentrations for chondritic particle U2022G1 are within a factor of 1.7 of CI for all elements detected with the exception of Br which is 37 times CI. Chondritic particle W7029*A27 is also near CI for Cr, Mn, Fe, Ni, Cu, Zn and Ge but enriched in Ga, Se, and Br by factors of 5.8, 3.5 and 8.4, respectively. The third particle of the cosmic dust class also showed high Br enriched relative to CI by a factor of 28. Br was also detected at a high level in an aluminum-rich particle classified as probable artificial terrestrial contamination but exhibiting a chondritic Fe/Ni ratio. Br was not detected in a fifth particle also classified terrestrial and exhibiting a crustal Fe/Ni ratio. If the high Br has a pre-terrestrial origin, the ubiquity of the effect suggests that a large fraction of the chondritic interplanetary dust particles derive from a parent body (bodies) not sampled in the meteorite collection. 26 refs., 3 figs., 3 tabs

Electrodeposition and properties of Zn, Cu, and Cu{sub 1−x} Zn{sub x} thin films

Energy Technology Data Exchange (ETDEWEB)

Özdemir, Rasim [Kilis Vocational High School, Kilis 7 Aralık University, 79000 Kilis (Turkey); Karahan, İsmail Hakkı, E-mail: ihkarahan@gmail.com [Department of Metallurgical and Materials Engineering, Faculty of Technology, Mustafa Kemal University, 31040 Hatay (Turkey)

2014-11-01

Highlights: • Cu, Zn and Cu–Zn deposits successfully deposited from the non-cyanide sulphate electrolyte. • The effect of alloying element was investigated on the electrical resistivity and the structure of Cu–Zn alloy. • The average crystallite size of the samples varied from 66 to 161 nm and decreased when the Zn and Cu combined in Cu–Zn. • Microstrain has been decreased with increasing crystallite size. • Electrical resistivity of alloy was obtained between the Zn and Cu films. - Abstract: The electrodeposition of Cu, Zn and Cu–Zn deposits from the non-cyanide Zn sulphate and Cu sulphate reduced by citrate at constant stirring speed has been investigated. The composition of the Cu–Zn bath was shown to influence the morphology, electrical resistivity, phase composition, and Cu and Zn content of the Cu–Zn deposits. Their structural and electrical properties have been investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDAX), cyclic voltammeter (CV) and current–voltage measurements against the temperature for electrical resistivity, respectively. XRD shows that Cu–Zn samples are polycrystalline phase. Resistivity results show that the copper film exhibits bigger residual resistivity than both the zinc and the Cu–Zn alloy. Theoretical calculations of the XRD peaks demonstrate that the average crystallite size of the Cu–Zn alloy decreased and microstrain increased when the Cu alloyed with zinc.

Synthesis of high aspect ratio of Ni 0.5Zn 0.5Fe 2O 4 platelets for electromagnetic devices

Science.gov (United States)

Hallynck, Sylvain; Pourroy, Geneviève; Vilminot, Serge; Jacquart, Pierre-Marie; Autissier, Denis; Vukadinovic, Nicolas; Pascard, Hubert

2006-01-01

Ni 0.5Zn 0.5Fe 2O 4 ferrite platelets of 5 to 300 μm have been obtained by reaction in a molten salt between hematite platelets, NiO and ZnO powders. The hematite platelets are obtained by a hydrothermal treatment in an alkaline medium between 180 and 270 °C through a dissolution-recrystallization mechanism from maghemite which crystallizes first. The key parameter for size control is the mixture alkalinity. The largest platelets are obtained for [Fe 3+] = 2.0 mol dm -3 and [OH -] = 15.3 N. The size distribution is narrow and the aspect ratio about 30. The reaction with nickel and zinc oxides yields the formation of polycrystalline platelets through a topotactic reaction allowing the platelet morphology, initial shape and size to be conserved. SEM observations reveal the ferrite platelets are made of adjacent micronic ferrite crystals with their [111] faces parallel to the platelet surface. Increasing the reaction temperature promotes an enlargement of the [111] faces. The respective solubilities of oxides and ferrites in the molten salts control the ferrite stoichiometry. KCl as a flux gives better results than NaCl with no modification of the crystal shape and no ZnO loss.

pH-Dependent Toxicity of High Aspect Ratio ZnO Nanowires in Macrophages Due to Intracellular Dissolution

KAUST Repository

H. Müller, Karin; Kulkarni, Jaideep; Motskin, Michael; Goode, Angela; Winship, Peter; Skepper, Jeremy N.; Ryan, Mary P.; Porter, Alexandra E.

2010-01-01

exploitation. In this study, ZnO nanowires were found to be toxic to human monocyte macrophages (HMMs) at similar concentrations as ZnCl2. Confocal microscopy on live cells confirmed a rise in intracellular Zn2+ concentrations prior to cell death. In vitro, Zn

Microwave-assisted silica coating and photocatalytic activities of ZnO nanoparticles

International Nuclear Information System (INIS)

Siddiquey, Iqbal Ahmed; Furusawa, Takeshi; Sato, Masahide; Suzuki, Noboru

2008-01-01

A new and rapid method for silica coating of ZnO nanoparticles by the simple microwave irradiation technique is reported. Silica-coated ZnO nanoparticles were characterized by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), high-resolution transmission electron microscopy (HR-TEM), CHN elemental analysis and zeta potential measurements. The FT-IR spectra and XPS clearly confirmed the silica coating on ZnO nanoparticles. The results of XPS analysis showed that the elements in the coating at the surface of the ZnO nanoparticles were Zn, O and Si. HR-TEM micrographs revealed a continuous and uniform dense silica coating layer of about 3 nm in thickness on the surface of ZnO nanoparticles. In addition, the silica coating on the ZnO nanoparticles was confirmed by the agreement in the zeta potential of the silica-coated ZnO nanoparticles with that of SiO 2 . The results of the photocatalytic degradation of methylene blue (MB) in aqueous solution showed that silica coating effectively reduced the photocatalytic activity of ZnO nanoparticles. Silica-coated ZnO nanoparticles showed excellent UV shielding ability and visible light transparency

Cu and Zn Isotopes as New Tracers of Early Solar Nebula and Asteroidal processes

Science.gov (United States)

LUCK, J.; BEN OTHMAN, D.; ALBAREDE, F.

2001-12-01

experiments have been conducted on various powder aliquots : HF-HCl cold(#1), HF-HCl hot(#2), HF-HNO3(#3) hot under pressure. Results show clearly that different Zn (and Cu) isotopic signatures (are preserved in early components. We stress that these are NOT anomalies for Zn : three isotopic ratios (66, 67 and 68 vs. 64) agree perfectly with a mass-dependent process. In particular Zn gets systematically lighter from the ``volatile" compounds (#1) to the refractory ones (#3). The rough correlation between O and Zn isotopes in these compounds could imply that Zinc, like Oxygen, experienced interaction between gaseous and solid states (e.g. spinels) at high temperatures. III- Iron Meteorites Non magmatic irons do not show much variation (less than 1 permil in range for both elements). On the other hand, meteorites from the IAB-IIICD group show not only large variations (3.5 permil in Zn), but also a negative correlation between Cu and Zn isotopes : this could be interpreted as a mixing between two endmembers, one of them being strongly fractionated in Zn isotopes. Fractionation of such extent (+3.7 permil) could reflect either volatilization during impact melting, or alteration on the parent body. Data available indicate that Cu and Zn isotopes are potentially important tracers for studying : 1- early solar nebula processes (e.g. high and low-T compounds exhibit different isotopic signatures); 2- meteorite parent body evolution (e.g. Cu and Zn isotopes correlate remarkably well with Oxygen isotopes in a well-established order : CV-CO-CM-CI). References (1)\\x90Marechal C., Telouk P. and Albarede F. (1999) Chem. Geol., 156, 251-273.

High-precision abundances of elements in Kepler LEGACY stars. Verification of trends with stellar age

Science.gov (United States)

Nissen, P. E.; Silva Aguirre, V.; Christensen-Dalsgaard, J.; Collet, R.; Grundahl, F.; Slumstrup, D.

2017-12-01

Context. A previous study of solar twin stars has revealed the existence of correlations between some abundance ratios and stellar age providing new knowledge about nucleosynthesis and Galactic chemical evolution. Aims: High-precision abundances of elements are determined for stars with asteroseismic ages in order to test the solar twin relations. Methods: HARPS-N spectra with signal-to-noise ratios S/N ≳ 250 and MARCS model atmospheres were used to derive abundances of C, O, Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Ni, Zn, and Y in ten stars from the Kepler LEGACY sample (including the binary pair 16 Cyg A and B) selected to have metallicities in the range - 0.15 LTE iron abundances derived from Fe I and Fe II lines. Available non-LTE corrections were also applied when deriving abundances of the other elements. Results: The abundances of the Kepler stars support the [X/Fe]-age relations previously found for solar twins. [Mg/Fe], [Al/Fe], and [Zn/Fe] decrease by 0.1 dex over the lifetime of the Galactic thin disk due to delayed contribution of iron from Type Ia supernovae relative to prompt production of Mg, Al, and Zn in Type II supernovae. [Y/Mg] and [Y/Al], on the other hand, increase by 0.3 dex, which can be explained by an increasing contribution of s-process elements from low-mass AGB stars as time goes on. The trends of [C/Fe] and [O/Fe] are more complicated due to variations of the ratio between refractory and volatile elements among stars of similar age. Two stars with about the same age as the Sun show very different trends of [X/H] as a function of elemental condensation temperature Tc and for 16 Cyg, the two components have an abundance difference, which increases with Tc. These anomalies may be connected to planet-star interactions. Based on spectra obtained with HARPS-N@TNG under programme A33TAC_1.Tables 1 and 2 are also available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http

The influence of sputtering power and O2/Ar flow ratio on the performance and stability of Hf-In-Zn-O thin film transistors under illumination

International Nuclear Information System (INIS)

Kim, Hyun-Suk; Park, Kyung-Bae; Son, Kyoung Seok; Park, Joon Seok; Maeng, Wan-Joo; Kim, Tae Sang; Lee, Kwang-Hee; Kim, Eok Su; Lee, Jiyoul; Suh, Joonki; Seon, Jong-Baek; Ryu, Myung Kwan; Lee, Sang Yoon; Lee, Kimoon; Im, Seongil

2010-01-01

The performance and stability of amorphous HfInZnO thin film transistors under visible light illumination were studied. The extent of device degradation upon negative bias stress with the presence of visible light is found to be strongly sensitive to the extent of photoelectric effect in the oxide semiconductor. Highly stable devices were fabricated by optimizing the deposition conditions of HfInZnO films, where the combination of high sputtering power and high O 2 /Ar gas flow ratio was found to result in the highest stability under bias stress experiments.

Uniaxial Negative Thermal Expansion, Negative Linear Compressibility, and Negative Poisson's Ratio Induced by Specific Topology in Zn[Au(CN)2]2.

Science.gov (United States)

Wang, Lei; Luo, Hubin; Deng, Shenghua; Sun, Ying; Wang, Cong

2017-12-18

The well-known idea of "structure determines properties" can be understood profoundly in the case of hexagonal zinc dicyanometalate. Using density functional theory (DFT) calculations, we show the uniaxial negative thermal expansion (NTE) and negative linear compressibility (NLC) properties of Zn[Au(CN) 2 ] 2 . The temperature dependence of phonon frequencies within the quasi-harmonic approximation (QHA) is investigated. The abnormal phonon hardening (frequency increase on heating) is detected in the ranges of 0-225, 320-345, and 410-430 cm -1 , which can be indicative of the unusual physical properties of Zn[Au(CN) 2 ] 2 . Due to the significance of low-energy phonon frequencies in Zn[Au(CN) 2 ] 2 , in this work, the corresponding vibrational mode of the lowest-frequency optical phonon at the zone center is analyzed. The specific topology of a springlike framework that will produce the effects of a compressed spring on heating and an extended spring under hydrostatic pressure is identified and leads to the coexistence of uniaxial-NTE and NLC behaviors in Zn[Au(CN) 2 ] 2 . The distinguishing phonon group velocity along the a axis and c axis facilitates different responses for both the axes under temperature and hydrostatic pressure field. Through an analysis and visualization of the spatial dependence of elastic tensors, it is found that a negative Poisson's ratio (NPR) is presented in all projection planes due to the specific topology.

Preparation, structural and optical characterization of ZnO, ZnO: Al nanopowder

Energy Technology Data Exchange (ETDEWEB)

Mohan, R. Raj [Department of ECE, Gojan School of Business and Technology, Chennai (India); Rajendran, K. [Department of Electronics, Government Arts College for Women, Ramanathapuram, TN (India); Sambath, K. [Department of ECS, Sri Krishna Arts and Science College, Coimbatore, TN (India)

2014-01-28

In this paper, ZnO and ZnO:Al nanopowders have been synthesized by low cost hydrothermal method. Zinc nitrate, hexamethylenetetramine (HMT) and aluminium nitrate are used as precursors for ZnO and AZO with different molar ratios. The structural and optical characterization of doped and un-doped ZnO powders have been investigated by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDAX), photoluminescence (PL) and ultra violet visible (UV-Vis) absorption studies. The SEM results show that the hydrothermal synthesis can be used to obtain nanoparticles with different morphology. It is observed that the grain size of the AZO nanoparticles increased with increasing of Al concentration. The PL measurement of AZO shows that broad range of green emission around 550nm with high intensity. The green emission resulted mainly because of intrinsic defects.

Aluminum-doped Zn O polycrystalline films prepared by co-sputtering of a Zn O-Al target

Energy Technology Data Exchange (ETDEWEB)

Becerril, M.; Silva L, H.; Guillen C, A.; Zelaya A, O. [Instituto Politecnico Nacional, Centro de Investigacion y de Estudios Avanzados, Departamento de Fisica, Apdo. Postal 14-740, 07000 Mexico D. F. (Mexico)

2014-07-01

Aluminum-doped Zinc oxide polycrystalline thin films (Azo) were grown on 7059 Corning glass substrates at room temperature by co-sputtering from a Zn O-Al target. The target was designed as follows, high purity elemental Aluminum was evaporated onto a Zn O target covering small areas. The structural, optical and electrical properties were analyzed as a function of Al content. The Al doped Zn O polycrystalline films showed an n-type conductivity. It was found that the electrical resistivity drops and the carrier concentration increases as a consequence of Al incorporation within the Zn O lattice. In both cases, the changes are of several orders of magnitude. From the results, we conclude that, using these Zn O-Al targets, n-type Al doped Zn O polycrystalline films with high transmittance and low resistivity can be obtained. The crystalline structure of the films was determined by X-ray diffraction. Atomic Force Microscopy images were obtained with an Auto probe C P (Veeco Metrology Group) Microscope. (Author)

Trace elements (Cu, Zn, and Hg) and δ13C/δ15N in seabird subfossils from three islands of the South China Sea and its implications.

Science.gov (United States)

Xu, Liqiang; Liu, Xiaodong; Nie, Yaguang

2016-05-01

Seabird subfossils were collected on three islands of the Xisha Archipelago, South China Sea. Via elemental analysis, we identified that bird guano was a significant source for heavy metals Cu, Zn, and Hg. Cu and Zn levels in these guano samples are comparable to their levels in wildbird feces, but guano Hg was lower than previously reported. Trophic positions significantly impacted transfer efficiency of heavy metals by seabirds. Despite of a common source, trace elements, as well as stable isotopes (i.e., guano δ(13)C and collagen δ(15)N), showed island-specific characteristics. Bird subfossils on larger island had relatively greater metal concentrations and revealed higher trophic positions. Partition of element and isotope levels among the islands suggested that transfer efficacy of seabirds on different islands was different, and bird species were probably unevenly distributed among the islets. Island area is possibly a driving factor for distributions of seabird species.

Structure and properties of ZnSxSe1-x thin films deposited by thermal evaporation of ZnS and ZnSe powder mixtures

Science.gov (United States)

Valeev, R. G.; Romanov, E. A.; Vorobiev, V. L.; Mukhgalin, V. V.; Kriventsov, V. V.; Chukavin, A. I.; Robouch, B. V.

2015-02-01

Interest to ZnSxSe1-x alloys is due to their band-gap tunability varying S and Se content. Films of ZnSxSe1-x were grown evaporating ZnS and ZnSe powder mixtures onto SiO2, NaCl, Si and ITO substrates using an original low-cost method. X-ray diffraction patterns and Raman spectroscopy, show that the lattice structure of these films is cubic ZnSe-like, as S atoms replace Se and film compositions have their initial S/Se ratio. Optical absorption spectra show that band gap values increase from 2.25 to 3 eV as x increases, in agreement with the literature. Because S atomic radii are smaller than Se, EXAFS spectra confirm that bond distances and Se coordination numbers decrease as the Se content decreases. The strong deviation from linearity of ZnSe coordination numbers in the ZnSxSe1-x indicate that within this ordered crystal structure strong site occupation preferences occur in the distribution of Se and S ions. The behavior is quantitatively confirmed by the strong deviation from the random Bernoulli distribution of the three sight occupation preference coefficients of the strained tetrahedron model. Actually, the ternary ZnSxSe1-x system is a bi-binary (ZnS+ZnSe) alloy with evanescent formation of ternary configurations throughout the x-range.

The measurement of the isotope ratios and concentrations of zinc by thermal ionization mass spectrometry using double isotope dilution

International Nuclear Information System (INIS)

Deng Zhongguo

1994-01-01

The isotope ratios and concentrations of zinc are measured by silicagel-thermal ionization mass spectrometry using the double isotope spikers. The double isotope spikers ( 70 Zn and 67 Zn-enriched isotopes) are used to correct the isotope mass fractionation for the zinc isotope ratios, and to certify the zinc concentrations in the unknown samples. The zinc concentrations of these double isotope spikers are surveyed by a spiker made of pure (99.99%) natural zinc metal powder. The correcting factors (f a , f t and f n ) of the zinc isotope ratios in the spiked mixture, spike and unspiked samples for the isotope mass fractionation, and the spike-to-unspiked ratios (X r ) of the zinc isotope r in the spiked mixture samples can be obtained to solve the matrix equations by numerical approximation. The natural zinc isotope ratios are: 64 Zn/ 67 Zn = 11.8498, 66 Zn/ 67 Zn = 6.7977, 68 Zn/ 67 Zn = 4.5730 and 70 Zn/ 67 Zn = 0.1520. The uncertainties determined of the isotope ratios and concentrations of zinc are +- 0.16% and +-0.31%, respectively

Spray pyrolysis deposition of Cu-ZnO and Zn-SnO{sub 2} solar cells

Energy Technology Data Exchange (ETDEWEB)

Khelfane, A.; Tarzalt, H.; Sebboua, B.; Zerrouki, H.; Kesri, N., E-mail: kesri5n@gmail.com [Faculty of Physics, University of Science and Technology of Houari Boumediene, Algiers (Algeria)

2015-12-31

Large-gap metal oxides, such as titanium, tin, and zinc oxides, have attracted great interest because of their remarkable potential in dye-sensitized solar cells (DSSC) and their low cost and simple preparation procedure. In this work, we investigated several Zn-SnO{sub 2} and Cu-ZnO thin films that were sprayed under different experimental conditions. We varied [Zn/[Sn] and [Cu/[Zn] ratios, calculated on atomic percent in the starting solution. We report some structural results of the films using X-ray diffraction. Optical reflection and transmission spectra investigated by an UV/VIS/NIR spectrophotometer permit the determination of optical constants. The direct band gap was deduced from the photon energy dependence of the absorption coefficient.

Trioctylphosphine-assisted morphology control of ZnO nanoparticles

Science.gov (United States)

Hong, Yun-Kun; Cho, GeonHee; Park, YoonSu; Oh, Soong Ju; Ha, Don-Hyung

2018-06-01

This study investigates the morphological change in colloidal ZnO nanoparticles (NPs) synthesized with trioctylphosphine (TOP). The addition of TOP to the synthesis causes an evolution in the shape of ZnO NPs to tadpole-like particles from quasi-spherical particles at 300 °C. The total length of the tadpole-like ZnO NPs can be modified by controlling the molar ratio of TOP to oleylamine (OLAM). The tadpole-like particles are elongated as the concentration of TOP increased but decreased when the addition of TOP is excessive. These tadpole-like ZnO NPs transform to quasi-spherical NPs regardless of the amount of TOP at a reaction time of 3 h at 300 °C. At 200 °C, the effect of TOP on the ZnO NP synthesis differs from that at 300 °C. The ZnO NPs synthesized by controlling the molar ratios of surfactant ligands (TOP:OLAM = 2:100 and 70:100) at 200 °C share similar amorphous structures, while a crystalline ZnO phase is formed when the reaction time is 3 h. X-ray photoelectron spectroscopy analysis shows that TOP influences the oxidation of ZnO and suggests that a combination of OLAM and TOP plays a role in controlling the shape of ZnO NPs. These results provide critical insights to the utilization of TOP for a shape controlling ligand in ZnO NPs and suggest a new route to design oxide NPs.

Element interactions and soil properties affecting the soil-to-plant transfer of six elements relevant to radioactive waste in boreal forest

International Nuclear Information System (INIS)

Roivainen, Paeivi; Makkonen, Sari; Holopainen, Toini; Juutilainen, Jukka

2012-01-01

Cobalt (Co), lead (Pb), molybdenum (Mo), nickel (Ni), uranium (U), and zinc (Zn) are among the elements that have radioactive isotopes in radioactive waste. Soil-to-plant transfer is a key process for possible adverse effects if these radionuclides are accidentally released into the environment. The present study aimed at investigating factors affecting such transfer in boreal forest. The plant species studied were blueberry (Vaccinium myrtillus), May lily (Maianthemum bifolium), narrow buckler fern (Dryopteris carthusiana), rowan (Sorbus aucuparia) and Norway spruce (Picea abies). Regression analyses were carried out to investigate the effects of the chemical composition and physical properties of soil on the soil-to-leaf/needle concentration ratios of Co, Mo, Ni, Pb, U and Zn. Soil potassium (K), magnesium (Mg), manganese (Mn), phosphorus (P) and sulphur (S) concentrations were the most important factors affecting the soil-to-plant transfer of the elements studied. Soil clay and organic matter contents were found to significantly affect plant uptake of Mo, Pb and U. Knowledge of the effects of these factors is helpful for interpretation of the predictions of radioecological models describing soil-to-plant transfer and for improving such models. (orig.)

Element interactions and soil properties affecting the soil-to-plant transfer of six elements relevant to radioactive waste in boreal forest

Energy Technology Data Exchange (ETDEWEB)

Roivainen, Paeivi; Makkonen, Sari; Holopainen, Toini; Juutilainen, Jukka [University of Eastern Finland, Department of Environmental Science, Kuopio (Finland)

2012-03-15

Cobalt (Co), lead (Pb), molybdenum (Mo), nickel (Ni), uranium (U), and zinc (Zn) are among the elements that have radioactive isotopes in radioactive waste. Soil-to-plant transfer is a key process for possible adverse effects if these radionuclides are accidentally released into the environment. The present study aimed at investigating factors affecting such transfer in boreal forest. The plant species studied were blueberry (Vaccinium myrtillus), May lily (Maianthemum bifolium), narrow buckler fern (Dryopteris carthusiana), rowan (Sorbus aucuparia) and Norway spruce (Picea abies). Regression analyses were carried out to investigate the effects of the chemical composition and physical properties of soil on the soil-to-leaf/needle concentration ratios of Co, Mo, Ni, Pb, U and Zn. Soil potassium (K), magnesium (Mg), manganese (Mn), phosphorus (P) and sulphur (S) concentrations were the most important factors affecting the soil-to-plant transfer of the elements studied. Soil clay and organic matter contents were found to significantly affect plant uptake of Mo, Pb and U. Knowledge of the effects of these factors is helpful for interpretation of the predictions of radioecological models describing soil-to-plant transfer and for improving such models. (orig.)

Electronic and elemental properties of the Cu2ZnSn(S,Se)4 surface and grain boundaries

International Nuclear Information System (INIS)

Haight, Richard; Shao, Xiaoyan; Wang, Wei; Mitzi, David B.

2014-01-01

X-ray and femtosecond UV photoelectron spectroscopy, secondary ion mass spectrometry and photoluminescence imaging were used to investigate the electronic and elemental properties of the CZTS,Se surface and its oxides. Oxide removal reveals a very Cu poor and Zn rich surface relative to bulk composition. O and Na are observed at the surface and throughout the bulk. Upward bending of the valence bands indicates the presence of negative charge in the surface region and the Fermi level is found near the band gap center. The presence of point defects and the impact of these findings on grain boundary properties will be described

Electronic and elemental properties of the Cu2ZnSn(S,Se)4 surface and grain boundaries

Science.gov (United States)

Haight, Richard; Shao, Xiaoyan; Wang, Wei; Mitzi, David B.

2014-01-01

X-ray and femtosecond UV photoelectron spectroscopy, secondary ion mass spectrometry and photoluminescence imaging were used to investigate the electronic and elemental properties of the CZTS,Se surface and its oxides. Oxide removal reveals a very Cu poor and Zn rich surface relative to bulk composition. O and Na are observed at the surface and throughout the bulk. Upward bending of the valence bands indicates the presence of negative charge in the surface region and the Fermi level is found near the band gap center. The presence of point defects and the impact of these findings on grain boundary properties will be described.

A study on morphology control and optical properties of ZnO nanorods synthesized by microwave heating

International Nuclear Information System (INIS)

Tsai, M.K.; Huang, C.C.; Lee, Y.C.; Yang, C.S.; Yu, H.C.; Lee, J.W.; Hu, S.Y.; Chen, C.H.

2012-01-01

In this study, we present morphology control investigations on zinc oxide (ZnO) nanorods synthesized by microwave heating of a mixture of zinc nitrate hexahydrate and hexamethylenetetramine (HMTA) precursors in deionized water (DI water). To study the morphology and structural variations of the obtained ZnO nanorods in different molar ratio of zinc nitrate hexahydrate to HMTA, X-ray diffraction (XRD), scanning electron microscopy (SEM) images, Raman scattering, and photoluminescence (PL) spectroscopy were measured. XRD and SEM images are utilized to examine the crystalline quality as well as the morphological properties of the ZnO nanorods. It is found that morphology control can be achieved by simply adjusting the reactant concentrations and the molar ratio of zinc nitrate hexahydrate to HMTA. Raman scattering and PL spectroscopy measurements were demonstrated to study the size- and shape-dependent optical response of the ZnO nanorods. The Raman scattering result shows that the intensity of LO mode at around 576 cm -1 decreases with the increase in the molar ratio of zinc nitrate hexahydrate to HMTA, indicating the reduction of defect concentrations in the synthesized ZnO nanorods. Room temperature PL spectrum of the synthesized ZnO nanorods reveals an ultraviolet (UV) emission peak and a broad visible emission. An enhancement of UV emission appears in the PL spectra as the molar ratio of zinc nitrate hexahydrate to HMTA increases, indicating that the defect concentration of the synthesized ZnO nanorods can be reduced by increasing the molar ratio. - Highlights: → Morphology of ZnO nanorods can be controlled via microwave-heating synthesis. → Molar ratio of Zn(NO 3 ) 2 .6H 2 O to C 6 H 12 N 4 affects the aspect ratio of ZnO nanorod. → ZnO nanorod showing higher aspect ratio can exhibit better optical properties.

Visible tunable lighting system based on polymer composites embedding ZnO and metallic clusters: from colloids to thin films

Science.gov (United States)

Truong, Thai Giang; Dierre, Benjamin; Grasset, Fabien; Saito, Noriko; Saito, Norio; Nguyen, Thi Kim Ngan; Takahashi, Kohsei; Uchikoshi, Tetsuo; Amela-Cortes, Marian; Molard, Yann; Cordier, Stéphane; Ohashi, Naoki

2016-01-01

The development of phosphor devices free of heavy metal or rare earth elements is an important issue for environmental reasons and energy efficiency. Different mixtures of ZnO nanocrystals with Cs2Mo6I8(OOC2F5)6 cluster compound (CMIF) dispersed into polyvinylpyrrolidone matrix have been prepared by very simple and low cost solution chemistry. The resulting solutions have been used to fabricate highly transparent and luminescent films by dip coating free of heavy metal or rare earth elements. The luminescence properties of solution and dip-coated films were investigated. The luminescence of such a system is strongly dependent on the ratios between ZnO and CMIF amounts, the excitation wavelength and the nature of the system. By varying these two parameters (ratio and wavelength), a large variety of colors, from blue to red as well as white, can be achieved. In addition, differences in the luminescence properties have been observed between solutions and thin films as well as changes of CMIF emission band maximum wavelength. This may suggest some possible interactions between the different luminophore centers, such as energy transfer or ligands exchange on the Mo6 clusters.

Solid Liquid Interdiffusion Bonding of Zn4Sb3 Thermoelectric Material with Cu Electrode

Science.gov (United States)

Lin, Y. C.; Lee, K. T.; Hwang, J. D.; Chu, H. S.; Hsu, C. C.; Chen, S. C.; Chuang, T. H.

2016-10-01

The ZnSb intermetallic compound may have thermoelectric applications because it is low in cost and environmentally friendly. In this study, a Zn4Sb3 thermoelectric element coated with a Ni barrier layer and a Ag reaction layer was bonded with a Ag-coated Cu electrode using a Ag/Sn/Ag solid-liquid interdiffusion bonding process. The results indicated that a Ni5Zn21 intermetallic phase formed easily at the Zn4Sb3/Ni interface, leading to sound adhesion. In addition, Sn film was found to react completely with the Ag layer to form a Ag3Sn intermetallic layer having a melting point of 480°C. The resulting Zn4Sb3 thermoelectric module can be applied at the optimized operation temperature (400°C) of Zn4Sb3 material as a thermoelectric element. The bonding strengths ranged from 14.9 MPa to 25.0 MPa, and shear tests revealed that the Zn4Sb3/Cu-joints fractured through the interior of the thermoelectric elements.

Volatile characteristic of trace elements during microwave pyrolysis of oil shale

Energy Technology Data Exchange (ETDEWEB)

Bai, Jing-ru; Wang, Qing; Kong, Ling-wen; Bai, Zhang [Northeast Dianli Univ., Jilin (China). Engineering Research Centre

2013-07-01

Oil shale is abundant in the world. Today, the industry of oil shale retorting for producing shale oil is developing owing to high price of oil in the world. In order to study migratory behavior of trace elements in oil shale at microwave pyrolysis, tests were performed in laboratory with oil shale of the Huadian deposit of China at different powers from 400 to 700 W. The trace elements As, Cd, Hg, Mo, Pb, Se, Cr, Cu, Ni, V, Zn, Ba, Co, Mn present in oil shale and shale char were determined by the inductively coupled plasma-mass spectrometry (ICP-MS). By comparing the content of trace elements in oil shale and shale char, distribution characteristics of trace elements at retorting were studied. The overall trends of volatile ratio of trace elements are ascending with higher microwave power and higher than the conventional pyrolysis. The differences in the volatile ratio indicate that the trace elements investigated are bound with the oil shale kerogen and its mineral matter in different manner. So Float-sink experiments (FSE) were performed on oil shale. Huadian oil shale has more included mineral. The volatilization of organic matter is not the main reason for the volatilization of trace elements in oil shale. The trace elements combined with the mineral elements may be also certain volatility.

Volatile element loss during planetary magma ocean phases

Science.gov (United States)

Dhaliwal, Jasmeet K.; Day, James M. D.; Moynier, Frédéric

2018-01-01

Moderately volatile elements (MVE) are key tracers of volatile depletion in planetary bodies. Zinc is an especially useful MVE because of its generally elevated abundances in planetary basalts, relative to other MVE, and limited evidence for mass-dependent isotopic fractionation under high-temperature igneous processes. Compared with terrestrial basalts, which have δ66Zn values (per mille deviation of the 66Zn/64Zn ratio from the JMC-Lyon standard) similar to some chondrite meteorites (∼+0.3‰), lunar mare basalts yield a mean δ66Zn value of +1.4 ± 0.5‰ (2 st. dev.). Furthermore, mare basalts have average Zn concentrations ∼50 times lower than in typical terrestrial basaltic rocks. Late-stage lunar magmatic products, including ferroan anorthosite, Mg- and Alkali-suite rocks have even higher δ66Zn values (+3 to +6‰). Differences in Zn abundance and isotopic compositions between lunar and terrestrial rocks have previously been interpreted to reflect evaporative loss of Zn, either during the Earth-Moon forming Giant Impact, or in a lunar magma ocean (LMO) phase. To explore the mechanisms and processes under which volatile element loss may have occurred during a LMO phase, we developed models of Zn isotopic fractionation that are generally applicable to planetary magma oceans. Our objective was to identify conditions that would yield a δ66Zn signature of ∼+1.4‰ within the lunar mantle. For the sake of simplicity, we neglect possible Zn isotopic fractionation during the Giant Impact, and assumed a starting composition equal to the composition of the present-day terrestrial mantle, assuming both the Earth and Moon had zinc 'consanguinity' following their formation. We developed two models: the first simulates evaporative fractionation of Zn only prior to LMO mixing and crystallization; the second simulates continued evaporative fractionation of Zn that persists until ∼75% LMO crystallization. The first model yields a relatively homogenous bulk solid

Influence of Rare Earth Elements on Microstructure and Mechanical Properties of Mg{sub 97}Zn{sub 1}Y{sub 1}RE{sub 1} Alloys

Energy Technology Data Exchange (ETDEWEB)

Kim, Jonghyun, E-mail: joindoc@kumamoto-u.ac.jp [Department of Material Science, Magnesium Research Center (MRC), Kumamoto University, Kumamoto, 860-8555 (Japan); Kawamura, Y. [Department of Material Science, Magnesium Research Center (MRC), Kumamoto University, Kumamoto, 860-8555 (Japan)

2013-06-20

Mg{sub 97}Zn{sub 1}Y{sub 1}RE{sub 1} (RE=La, Ce, Nd and Sm, at. %) alloys were prepared by high-frequency induction melting in an Ar atmosphere. Rods were extruded at 623 K and a ram speed of 2.5 mm·s{sup −1} using a circular die with an extrusion ratio of 10. The microstructure and mechanical properties of the extruded alloys were investigated. The Mg{sub 97}Zn{sub 1}Y{sub 1}Nd{sub 1} and Mg{sub 97}Zn{sub 1}Y{sub 1}Sm{sub 1} alloys consisted of only two phases: α-Mg and a Mg-RE intermetallic compound. The Mg{sub 97}Zn{sub 1}Y{sub 1}La{sub 1} and Mg{sub 97}Zn{sub 1}Y{sub 1}Ce{sub 1} alloys consisted of three phases: α-Mg, a Mg-RE intermetallic compound, and a Mg{sub 12}ZnY phase with a long-period stacking ordered (LPSO) phase. Additionally, after extrusion, the three-phase Mg{sub 97}Zn{sub 1}Y{sub 1}RE{sub 1} alloys, i.e., those with an LPSO phase, had a stratified microstructure and exhibited better mechanical properties than those without an LPSO. At room temperature, the yield strength and ultimate tensile strength of the three-phase Mg{sub 97}Zn{sub 1}Y{sub 1}La{sub 1} and Mg{sub 97}Zn{sub 1}Y{sub 1}Ce{sub 1} alloys were 381–384 MPa and 427–429 MPa, respectively, and yield strengths greater than 280 MPa were observed at the elevated temperature of 523 K.

Effect of process conditions and chemical composition on the microstructure and properties of chemically vapor deposited SiC, Si, ZnSe, ZnS and ZnS(x)Se(1-x)

Science.gov (United States)

Pickering, Michael A.; Taylor, Raymond L.; Goela, Jitendra S.; Desai, Hemant D.

1992-01-01

Subatmospheric pressure CVD processes have been developed to produce theoretically dense, highly pure, void-free and large area bulk materials, SiC, Si, ZnSe, ZnS and ZnS(x)Se(1-x). These materials are used for optical elements, such as mirrors, lenses and windows, over a wide spectral range from the VUV to the IR. We discuss the effect of CVD process conditions on the microstructure and properties of these materials, with emphasis on optical performance. In addition, we discuss the effect of chemical composition on the properties of the composite material ZnS(x)Se(1-x). We first present a general overview of the bulk CVD process and the relationship between process conditions, such as temperature, pressure, reactant gas concentration and growth rate, and the microstructure, morphology and properties of CVD-grown materials. Then we discuss specific results for CVD-grown SiC, Si, ZnSe, ZnS and ZnS(x)Se(1-x).

The Effect of Risk Factors on the Levels of Chemical Elements in the Tibial Plateau of Patients with Osteoarthritis following Knee Surgery

Directory of Open Access Journals (Sweden)

Natalia Lanocha-Arendarczyk

2015-01-01

Full Text Available The aim of this study was to evaluate the aforementioned chemical elements in tibial plateau samples obtained during knee arthroplasty. The gender-specific analysis of chemical element levels in the bone samples revealed that there were statistically significant differences in the concentration of Pb and Se/Pb ratio. The contents of elements in the tibial plateau in the patients with osteoarthritis (OA can be arranged in the following descending order: F− > K > Zn > Fe > Sr > Pb > Mn > Se > Cd > THg. We observed statistical significant effects of environmental factors including smoking, seafood diet, and geographical distribution on the levels of the elements in tibial bone. Significant positive correlation coefficients were found for the relationships K-Cd, Zn-Sr, Zn-F−, THg-Pb, Pb-Cd, Se-Se/Pb, Se-Se/Cd, Se/Pb-Se/Cd, Pb-Cd/Ca, Cd-Cd/Ca, and F−-F−/Ca·1000. Significant negative correlations were found for the relationships THg-Se/Pb, Pb-Se/Pb, Cd-Se/Pb, K-Se/Cd, Pb-Se/Cd, Cd-Se/Cd, THg-Se/THg, Pb-Se/THg, Se-Pb/Cd, Zn-Cd/Ca, and Se/Cd-Cd/Ca. The results reported here may provide a basis for establishing reference values for the tibial plateau in patients with OA who had undergone knee replacement surgery. The concentrations of elements in the bone with OA were determined by age, presence of implants, smoking, fish and seafood diet, and sport activity.

Structural characterization and optical properties of perovskite ZnZrO 3 nanoparticles

KAUST Repository

Zhu, Xinhua

2014-03-17

Perovskite ZnZrO3 nanoparticles were synthesized by hydrothermal method, and their microstructures and optical properties were characterized. The crystallinity, phase formation, morphology and composition of the as-synthesized nanoparticles were characterized by X-ray diffraction (XRD), selected area electron diffraction (SAED), high-resolutiontransmission electron microscopy (HRTEM), and energy-dispersive X-ray (EDX) spectroscopy analysis, respectively. TEM images demonstrated that the average particle size of the ZnZrO3 powders was increased with increasing the Zn/Zr molar ratios in the precursors, and more large ZnZrO3 particles with cubic morphology were observed at high Zn/Zr molar ratios. In addition, the phase structures of the ZnZrO3 particles were also evolved from a cubic to tetragonal perovskite phase, as revealed by XRD and SAED patterns. HRTEM images demonstrate that surface structures of the ZnZrO3 powders synthesized at high Zn/Zr molar ratios, are composed of corners bound by the {100} mini-facets, and the surface steps lying on the {100} planes are frequently observed, whereas the (101) facet isoccasionally observed. The formation of such a rough surface structure is understood from the periodic bond chain theory. Quantitative EDX analyses demonstrated that the atomic concentrations (at.%) of Zn:Zr:O in the particles were 20.70:21.07:58.23, as close to the composition of ZnZrO3. In the optical spectra, a significant red shift of the absorption edges (for the ZnZrO3 nanopowders) from UV to visible region (from 394 to 417 nm) was observed as increasing the Zn/Zr molar ratios in the precursors, which corresponds to that the band gap energies of the ZnZrO3 nanopowders can be continuously tuned from 3.15 to 2.97 eV. This opens an easy way to tune the band gap energies of the ZnZrO3 nanopowders. © 2014 The American Ceramic Society.

Trace element geochemistry and mineralogy of coal from Samaleswari open cast coal block (S-OCB), Eastern India

Science.gov (United States)

Saha, Debasree; Chatterjee, Debashis; Chakravarty, Sanchita; Mazumder, Madhurina

2018-04-01

Coal samples of Samaleswari open cast coal block (S-OCB) are high ash (Aad, mean value 35.43%) and low sulphur content (St, on dry basis, mean value 0.91% analysis. The work is further supported by the use of chemical fractionation experiment that reveals the multi mode of occurrence of several environmentally concern and interested trace elements (Sb, As, Be, Cd, Cr, Co, Cu, Pb, Mn, Ni, Zn). Among the analysed trace elements Co, Mn and Zn have major silicate association along with significant carbonate/oxide/monosulfide association. Whereas As, Cd, Cu, Pb and Ni have dominant pyritic association with notable silicate and carbonate/oxide/monosulfide association. The rest three elements (Sb, Be, Cr) have principally organic association with minor silicate and carbonate/oxide/monosulfide association. The stratigraphic variation of organo-mineral matrix content and detrital-authigenic mineral ratio are primarily related to coal rank. Geochemical character of coal also reflects a light towards proper utilisation of S-OCB coal from technical and environmental view point.

Horizontally-connected ZnO-graphene hybrid films for multifunctional devices

Energy Technology Data Exchange (ETDEWEB)

Lim, Yi Rang [Thin Film Materials Research Center, Korea Research Institute of Chemical Technology, Yuseong Post Office Box 107, Daejeon 305-600 (Korea, Republic of); School of Semiconductor and Chemical Engineering, Semiconductor Physics Research Center (SPRC), Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Song, Wooseok; Lee, Young Bum; Kim, Seong Ku; Han, Jin Kyu; Myung, Sung; Lee, Sun Sook; An, Ki-Seok [Thin Film Materials Research Center, Korea Research Institute of Chemical Technology, Yuseong Post Office Box 107, Daejeon 305-600 (Korea, Republic of); Choi, Chel-Jong [School of Semiconductor and Chemical Engineering, Semiconductor Physics Research Center (SPRC), Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Lim, Jongsun, E-mail: jslim@krict.re.kr [Thin Film Materials Research Center, Korea Research Institute of Chemical Technology, Yuseong Post Office Box 107, Daejeon 305-600 (Korea, Republic of)

2016-08-30

Highlights: • We designed horizontally-connected ZnO and graphene hybrid nanofilms with improved flexibility for multifunctional nanodevices including high performance TFTs. • The photocurrent on-off ratio, response time, and recovery time of the hybrid photodetectors were estimated to be 10{sup 2}, 34 s, and 27 s, respectively. The photocurrent from the hybrid photodetector decreased only by two-fold, whereas a significant decrease in photocurrent by two orders of magnitude was observed from the ZnO thin film based photodetectors after 10{sup 5} cycles of 5-mm radius bending. • The hybrid thin film transistors exhibited unipolar n-channel transistor behavior with electron mobility of 68.7 cm{sup 2}/V s and on-off ratio of 10{sup 7}. - Abstract: Here we designed horizontally-connected ZnO thin films and graphene in order to combine advantages of ZnO thin films, which are high on/off ratio and photo responsivity, and the superior mobility and sensitivity of graphene for applications in thin film transistors (TFTs) and flexible photodetectors. To synthesize the ZnO/graphene hybrid films, a 70-nm-thick ZnO thin film with a uniformly flat surface deposited by the atomic layer deposition process was horizontally connected with highly crystalline monolayer graphene grown by thermal chemical vapor deposition. The photocurrent on-off ratio, response time, and recovery time of the hybrid photodetectors were estimated to be 10{sup 2}, 34 s, and 27 s, respectively. The photocurrent from the hybrid photodetector decreased only by two-fold, whereas a significant decrease in photocurrent by two orders of magnitude was observed from the ZnO thin film based photodetectors after 10{sup 5} cycles of 5-mm radius bending. The hybrid TFT exhibited unipolar n-channel transistor behavior with electron mobility of 68.7 cm{sup 2}/V s and on-off ratio of 10{sup 7}.

Combinatorial study of WInZnO films deposited by rf magnetron co-sputtering

International Nuclear Information System (INIS)

Oh, Byeong-Yun; Park, Jae-Cheol; Lee, Young-Jun; Cha, Sang-Jun; Kim, Joo-Hyung; Kim, Kwang-Young; Kim, Tae-Won; Heo, Gi-Seok

2011-01-01

The compositional dependence of co-sputtered tungsten indium zinc oxide (WInZnO) film properties was first investigated by means of a combinatorial technique. Indium zinc oxide (IZO) and WO 3 targets were used with different target power. W composition ratio [W/(In+Zn+W)] was varied between 3 and 30 at% and film thickness was reduced as the sample position moved toward WO 3 target. Furthermore, the optical bandgap energy increased gradually, which might be affected by the reduction in film thickness. All the WInZnO films showed an amorphous phase regardless of the W/(In+Zn+W) ratio. As the W/(In+Zn+W) ratio in WInZnO films increased, the carrier concentration was restricted, causing the increase in electrical resistivity. W cations worked as oxygen binders in determining the electronic properties, resulting in suppressing the formation of oxygen vacancies. Consequentially, W metal cations were effectively incorporated into the WInZnO films as a suppressor against the oxygen vacancies and the carrier generation by employing the combinatorial technique. - Graphical abstract: The film thickness and the sheet resistance (R s ) with respect to the sample position of WInZnO films, which is compositionally graded by rf power for each target, are exhibited. Highlights: → The compositional dependence of co-sputtered WInZnO film properties is first investigated. → W cations work as oxygen binders in determining the electronic properties. → All the WInZnO films show an amorphous phase regardless of the W/(In+Zn+W) ratio. → W metal cations are effectively incorporated into the WInZnO films by the combinatorial technique.

A flexible UV nanosensor based on reduced graphene oxide decorated ZnO nanostructures

Science.gov (United States)

Wang, Zhenxing; Zhan, Xueying; Wang, Yajun; Muhammad, Safdar; Huang, Ying; He, Jun

2012-03-01

A low-cost, compatible with flexible electronics, high performance UV sensor has been achieved from a reduced graphene oxide (RGO) decorated hydrangea-like ZnO film on a PDMS substrate. The hydrangea-like ZnO UV sensor has the best UV sensing performance among devices made of three kinds of ZnO nanostructures synthesized by a hydrothermal method, and demonstrated a dramatic enhancement in on/off ratio and photoresponse current by introducing an appropriate weight ratio of RGO. The on/off ratio of the 0.05% RGO/ZnO sensor increases almost one order of magnitude compared to that of a pristine hydrangea-like ZnO UV sensor. While for the 5% RGO decorated ZnO sensor, the photoresponse current reaches as high as ~1 μA and exceeds 700 times that of a ZnO UV sensor. These results indicate that RGO is an appropriate material to enhance the performance of ZnO nanostructure UV sensors based on its unique features, especially the high optical transparency and excellent electronic conductivity. Our findings will make RGO/ZnO nanohybrids extraordinarily promising in optoelectronics, flexible electronics and sensor applications.

Trace and toxic elements in foodstuffs in Japan

International Nuclear Information System (INIS)

Muramatsu, Y.; Sumiya, M.; Yanagisawa, K.; Ohmomo, Y.

1994-01-01

Concentrations of trace elements in several foodstuffs collected in Japan were analyzed by neutron activation analysis (NAA), inductively-coupled plasma atomic emission spectrometry (ICP-AES) and anodic striping voltametry (ASV). The elements analyzed were as follows: Zn, Se, As, Hg, Cs, Cr, Co, Fe, Rb, Br and K by NAA; Mn, Ba, Sr, Mg, Ca, P, K, Zn, Cu and Fe by ICP-AES; and Pb, Cd, Cu and Zn by ASV. Because of the high consumption of rice in Japan, the focus of analysis was on this foodstuff. Concentrations of K, Mg, Mn, P and Zn in different polished rice samples were similar, whereas those of Br, Co, Cs, Rb and Se varied. Levels of toxic elements in polished rice were generally lower than those in other foodstuffs. The highest concentrations of As, Hg, Se and Zn were found in marine products, i.e.. Hijiki-algae (As: 59 mg/kg, dry), tuna (Hg: 1.1 mg/kg, dry), bonito (Se: 4.5 mg/kg, dry) and oysters (Zn: 350 mg/kg, dry). Dietary intakes of As, Ca, Cd, Cu, Fe, Hg, K, Mg, Mn, P, Pb, Se and Zn by Japanese were estimated by using these analytical results and published food consumption data in Japan. We have also identified the major sources of the elements in dietary intakes as follows: (a) about 90% of the As was derived from marine products (fish and seaweed); (b) about 70% of the Hg was derived from fish; (c) about 40-60% of the Cd and the Mn and 20-40% of the Zn, Cu and Mg was derived from rice; (d) selenium was mostly derived from fish, meat and eggs; (e) more than 20% of the Ca was derived from milk and milk products; (f) elements such as Fe, K, P and Pb was derived from different sorts of foodstuffs. (author). 7 refs, 1 fig., 7 tabs

Relationships Between Element Contents in Polish Children's and Adolescents' Hair.

Science.gov (United States)

Długaszek, Maria; Skrzeczanowski, Wojciech

2017-11-01

Environment, sex, and age are the main factors which determine the elemental composition of hair. The objective of the study is to determine the contents of calcium (Ca), magnesium (Mg), zinc (Zn), copper (Cu), iron (Fe), lead (Pb), and cadmium (Cd) in girls' and boys' hair in five age groups (within 1-19-year range) corresponding to successive human ontogenesis phases as well as to evaluate the relationships between these elements. Quantitative analysis has been carried out using atomic absorption spectrometry (AAS). Experimental results were analyzed using classic and principal component (PCA) statistical analyses. In particular, differences between contents of particularly Ca, Mg, and Zn in girls' and boys' hair were found, and substantial differences between age groups were stated. In general, larger amounts of Ca, Mg, and Zn as compared to boys' hair have been observed for girls' hair and higher toxic element (Pb, Cd) contents for boys were measured in some age groups. An increasing trend was found for bioelements (Ca, Mg, Zn) both for girls and boys in all age groups, while for Cu and Fe content, changes are insignificant and even decreasing for teenagers. The most frequently correlating element pairs are Ca-Mg, Ca-Zn, Mg-Zn, and Pb-Cd. Classic and PCA statistics show, in general, a satisfactory consistence. The elemental composition of hair varies depending on the gender and age of children and young people.

Investigation of the pulsed electrochemical deposition of ZnO

International Nuclear Information System (INIS)

Dunkel, Christian; Lüttich, Franziska; Graaf, Harald; Oekermann, Torsten; Wark, Michael

2012-01-01

The influence of pulse parameters on the morphology of ZnO prepared by pulsed cathodic electrodeposition from oxygen-saturated aqueous ZnCl 2 solution on ITO (indium tin oxide)/glass substrates was investigated. It was found that the ratio between the pulse and the pause duration has a crucial influence on the crystal growth, reaching the highest density of the films with pause/pulse-ratios between 0.25 and 1. Longer pauses cause an Ostwald-like ripening of the ZnO crystals and therewith a strong change in the crystal morphology from roundly shaped to hexagonal. Also the hydrophilicity of the substrate resulting from pre-treatment has a crucial influence on the deposited films, leading to films only consisting of few large and separately grown ZnO crystals for highly hydrophilic substrates and an increasing fraction of small densely grown ZnO crystals with increasing hydrophobicity.

The concentration ratio of alkaline earth elements calcium, barium and strontium in grains of diploid, tetraploid and hexaploid wheat

Directory of Open Access Journals (Sweden)

Maksimović Ivana V.

2017-01-01

Full Text Available Even though calcium (Ca, strontium (Sr and barium (Ba belong to the same group of the periodic table of elements, and thus have similar chemical features, their importance for plants differs greatly. Since plants do not have the ability to completely dis­criminate between essential (e.g. Ca and non-essential elements (e.g. Sr and Ba, they read­ily take all of them up from soil solution, which is reflected in the ratios of concentrations of those elements in plant tissues, and it influences their nutritive characteristics. The ability of plant species and genotypes to take up and accumulate chemical elements in their different tissues is related to their genetic background. However, differences in chemical composition are the least reflected in their reproductive parts. Hence, the aim of this study was to evaluate ratios of concentrations of Ca, Sr and Ba in the whole grain of diploid and tetraploid wheat - ancestors of common wheat, as well as in hexaploid commercial cultivars, grown in the field, at the same location, over a period of three years. The investigated genotypes accumulated Ca, Sr and Ba at different levels, which is reflected in the ratio of their concentrations in the grain. The lowest ratio was established between Ba and Sr, followed by Ca and Ba, while the highest ratio was between Ca and Sr. Moreover, the results have shown that the year of study, genotype and the combination highly significantly affected the ratio of the concentration Ca:Sr, Ca:Ba, and Ba:Sr.

Photoluminescence quenching and enhanced spin relaxation in Fe doped ZnO nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Ovhal, Manoj M.; Santhosh Kumar, A. [Department of Materials Engineering, Defence Institute of Advanced Technology, Girinagar, Pune 411025 (India); Khullar, Prerna [School of Materials Science and Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India); Kumar, Manjeet [Department of Materials Engineering, Defence Institute of Advanced Technology, Girinagar, Pune 411025 (India); Abhyankar, A.C., E-mail: ashutoshabhyankar@gmail.com [Department of Materials Engineering, Defence Institute of Advanced Technology, Girinagar, Pune 411025 (India)

2017-07-01

Cost-effective ultrasonically assisted precipitation method is utilized to synthesize Zinc oxide (ZnO) nanoparticles (NPs) at room temperature and the effect of Iron (Fe) doping on structural, optical and spin relaxation properties also presented. As-synthesized pure and Fe doped ZnO NPs possess a perfect hexagonal growth habit of wurtzite zinc oxide, along the (101) direction of preference. With Fe doping, ‘c/a’ ratio and compressive lattice strain in ZnO NPs are found to reduce and increase, respectively. Raman studies demonstrate that the E{sub 1} longitudinal optical (LO) vibrational mode is very weak in pure which remarkably enhanced with Fe doping into ZnO NPs. The direct band gap energy (E{sub g}) of the ZnO NPs has been increased from 3.02 eV to 3.11 eV with Fe doping. A slight red-shift observed with strong green emission band, in photoluminescence spectra, is strongly quenched in 6 wt.% Fe doped ZnO NPs. The field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) reveals spherical shape of ZnO NPs with 60–70 nm, which reduces substantially on Fe doping. The energy dispersive X-ray spectrum and elemental mapping confirms the homogeneous distribution of Fe in ZnO NPs. Moreover, the specific relaxation rate (R{sub 2sp} = 1/T{sub 2}) has been measured using Carr-Purcell-Meiboom-Gill (CPMG) method and found to be maximum in 6 wt.% Fe doped ZnO NPs. Further, the correlation of structural, optical and dynamic properties is proposed. - Highlights: • Pure ZnO and Fe doped ZnO NPs were successfully prepared by cost effective ultrasonically assisted precipitation method. • The optical band gap of ZnO has been enhanced form 3.02–3.11 eV with Fe doping. • PL quenching behaviour has been observed with Fe{sup 3+} ions substitution in ZnO lattice. • Specific relaxation rate (R{sub 2sp} = 1/T{sub 2}) has been varied with Fe doping and found to be maximum in 6 wt.% Fe doped ZnO NPs.

Techniques for intrinsically labeling wheat with 65Zn

International Nuclear Information System (INIS)

Starks, T.L.; Johnson, P.E.

1985-01-01

Several techniques of intrinsically labeling wheat with 65 Zn were compared: stem injection of 65 Zn, stem injection of 65 Zn + ZnSO 4 , foliar application of 65 Zn, and the addition of 65 Zn to a hydroponic solution. Incorporation levels of 65 Zn into the grain were 62.6% stem injection, 45.2% stem-injected 65 Zn + ZnSO 4 , 57.5% foliar application, and 2.3% hydroponic solution. Four protein fractions were extracted from fat-free whole wheat flour. Distribution of 65 Zn into the protein fractions for all treatments, was 8.5-20.3% in albumins and globulins, 47.4-60.3% in glutenins, 1-2.6% in gliadins, and 9.8-28.3% in the remaining proteins. Separation of the fractions by gel chromatography showed that protein and Zn distributions were similar among the treatments and when compared to the controls. Zinc-65 distribution was similar to the natural Zn distribution. These data illustrate that stem-injected 65 Zn is incorporated in the same manner and ratios as Zn naturally utilized by wheat

Cell-Sediment Separation and Elemental Stoichiometries in Extreme Environments

Science.gov (United States)

Neveu, M.; Poret-peterson, A. T.; Lee, Z. M.; Anbar, A. D.; Elser, J. J.

2012-12-01

Better understanding of the coupling of major biogeochemical cycles requires knowledge of the cellular elemental composition of key microbes. This is difficult in benthic sediments and mats, because of the contributions of non-living components. We are particularly interested in microbial extremophiles, and therefore sought to determine and interpret bulk and cellular elemental ratios in complex field-collected sediment samples from diverse hot spring ecosystems of Yellowstone National Park (YNP). These samples covered a broad range of temperature, pH, and chemical composition. We also sought to extend stoichiometric analysis to a broader suite of elements, including metals (Fe, Ni, Cu, Zn, Mo, etc.) of biological importance (Sterner and Elser, 2002). To overcome the challenge of rigorously isolating communities from their complex mineral matrices (Havig et al., 2011), we adapted a cell-sediment separation procedure from Amalfitano and Fazi (2008). The method involves chemical (use of a detergent and a chelating agent) and physical methods (stirring, gentle sonication, and gradient centrifugation) to break the microbe-mineral bonds. C and N elemental and isotopic abundances were determined by elemental analysis - isotope ratio - mass spectrometry (EA-IR-MS), while P, Na, Mg, Al, K, Ca, V, Cr, Fe, Co, Ni, Cu, Zn, and Mo contents were determined by inductively coupled plasma - mass spectrometry (ICP-MS). We sought to assess the existence of an "Extended Redfield Ratio" (ERR) for these microbes; that is, to establish the multi-element stoichiometric envelope within which extremophilic microbes must operate. Elemental and isotopic mass balance analyses of cultured E. coli before and after separation showed that our procedure preserved cellular C, N, P, Fe, and trace metal contents: neither loss of these elements (e.g., by cell lysis) nor contamination by reagents were observed. On the other hand, cation-forming elements (Na, Mg, K, Ca), were not conserved. Cell

Trace elements and stable isotope ratios (δ13C and δ15N) in fish from deep-waters of the Sulu Sea and the Celebes Sea

International Nuclear Information System (INIS)

Asante, Kwadwo Ansong; Agusa, Tetsuro; Kubota, Reiji; Mochizuki, Hiroko; Ramu, Karri; Nishida, Shuhei; Ohta, Suguru; Yeh, Hsin-ming; Subramanian, Annamalai; Tanabe, Shinsuke

2010-01-01

Trace elements (TEs) and stable isotope ratios (δ 15 N and δ 13 C) were analyzed in fish from deep-water of the Sulu Sea, the Celebes Sea and the Philippine Sea. Concentrations of V and Pb in pelagic fish from the Sulu Sea were higher than those from the Celebes Sea, whereas the opposite trend was observed for δ 13 C. High concentrations of Zn, Cu and Ag were found in non-migrant fish in deep-water, while Rb level was high in fish which migrate up to the epipelagic zone, probably resulting from differences in background levels of these TEs in each water environment or function of adaptation to deep-water by migrant and non-migrant species. Arsenic level in the Sulu Sea fish was positively correlated with δ 15 N, indicating biomagnification of arsenic. To our knowledge, this is the first study on relationship between diel vertical migration and TE accumulation in deep-water fish.

Single and couple doping ZnO nanocrystals characterized by positron techniques

Science.gov (United States)

Pasang, Tenzin; Namratha, Keerthiraj; Guagliardo, Paul; Byrappa, Kullaiah; Ranganathaiah, Chikkakuntappa; Samarin, S.; Williams, J. F.

2015-04-01

Zinc oxide (ZnO) nanocrystals have been synthesized using a mild hydrothermal process using low temperatures and pressures with the advantages of free growth catalyst, low cost and alternative technology. Positron annihilation lifetime spectroscopy and coincidence Doppler broadening (CDB) spectroscopic methods have been used to investigate the roles of single- and co-dopants and native defects of the ZnO nanocrystals controlled by the synthesis process. It is shown that single Ag1+ and Pd2+ dopants occupy interstitial sites of the ZnO lattice and single Ru3+ doping replaces Zn vacancies substitutionally with a significant effect on the CDB momentum ratio curves when compared using ZnO as the reference spectrum. The co-doping of the ZnO lattice with (Sn4+ + Co2+) shows similar CDB ratios as Ru3+ single-doping. Also co-doping with (Ag1+ + Pd2+) or (Ag1+ + W6+) shows significant decreases in the band gap energy up to about 12.6% compared to single doping. The momentum ratio curves, referenced to undoped ZnO, indicate dopants in interstitial and substitutional sites. The presence of transition metal ions interstitially will trap electrons which resist the recombination of electrons and in turn affect the conductivity of the material.

Single and couple doping ZnO nanocrystals characterized by positron techniques

International Nuclear Information System (INIS)

Pasang, Tenzin; Namratha, Keerthiraj; Byrappa, Kullaiah; Guagliardo, Paul; Ranganathaiah, Chikkakuntappa; Samarin, S; Williams, J F

2015-01-01

Zinc oxide (ZnO) nanocrystals have been synthesized using a mild hydrothermal process using low temperatures and pressures with the advantages of free growth catalyst, low cost and alternative technology. Positron annihilation lifetime spectroscopy and coincidence Doppler broadening (CDB) spectroscopic methods have been used to investigate the roles of single- and co-dopants and native defects of the ZnO nanocrystals controlled by the synthesis process. It is shown that single Ag 1+ and Pd 2+ dopants occupy interstitial sites of the ZnO lattice and single Ru 3+ doping replaces Zn vacancies substitutionally with a significant effect on the CDB momentum ratio curves when compared using ZnO as the reference spectrum. The co-doping of the ZnO lattice with (Sn 4+ + Co 2+ ) shows similar CDB ratios as Ru 3+ single-doping. Also co-doping with (Ag 1+ + Pd 2+ ) or (Ag 1+ + W 6+ ) shows significant decreases in the band gap energy up to about 12.6% compared to single doping. The momentum ratio curves, referenced to undoped ZnO, indicate dopants in interstitial and substitutional sites. The presence of transition metal ions interstitially will trap electrons which resist the recombination of electrons and in turn affect the conductivity of the material. (paper)

Inhibition of growth of S. epidermidis by hydrothermally synthesized ZnO nanoplates

Science.gov (United States)

Abinaya, C.; Mayandi, J.; Osborne, J.; Frost, M.; Ekstrum, C.; Pearce, J. M.

2017-07-01

The antibacterial effect of zinc oxide (ZnO#1) as prepared and annealed (ZnO#2) at 400 °C, Cu doped ZnO (CuZnO), and Ag doped ZnO (AgZnO) nanoplates on Staphylococcus epidermidis was investigated for the inhibition and inactivation of cell growth. The results shows that pure ZnO and doped ZnO samples exhibited antibacterial activity against Staphylococcus epidermidis (S. epidermidis) as compared to tryptic soy broth (TSB). Also it is observed that S. epidermidis was extremely sensitive to treatment with ZnO nanoplates and it is clear that the effect is not purely depend on Cu/Ag. Phase identification of a crystalline material and unit cell dimensions were studied by x-ray powder diffraction (XRD). The scanning electron microscopy (SEM) provides information on sample’s surface topography and the EDX confirms the presence of Zn, O, Cu and Ag. X-ray photo-electron spectroscopy (XPS) was used to analyze the elemental composition and electronic state of the elements that exist within the samples. These studies confirms the formation of nanoplates and the presence of Zn, O, Ag, Cu with the oxidation states  +2, -2, 0 and  +2 respectively. These results indicates promising antibacterial applications of these ZnO-based nanoparticles synthesized with low-cost hydrothermal methods.

Structural and elemental characterization of high efficiency Cu2ZnSnS4 solar cells

Science.gov (United States)

Wang, Kejia; Shin, Byungha; Reuter, Kathleen B.; Todorov, Teodor; Mitzi, David B.; Guha, Supratik

2011-01-01

We have carried out detailed microstructural studies of phase separation and grain boundary composition in Cu2ZnSnS4 based solar cells. The absorber layer was fabricated by thermal evaporation followed by post high temperature annealing on hot plate. We show that inter-reactions between the bottom molybdenum and the Cu2ZnSnS4, besides triggering the formation of interfacial MoSx, results in the out-diffusion of Cu from the Cu2ZnSnS4 layer. Phase separation of Cu2ZnSnS4 into ZnS and a Cu-Sn-S compound is observed at the molybdenum-Cu2ZnSnS4 interface, perhaps as a result of the compositional out-diffusion. Additionally, grain boundaries within the thermally evaporated absorber layer are found to be either Cu-rich or at the expected bulk composition. Such interfacial compound formation and grain boundary chemistry likely contributes to the lower than expected open circuit voltages observed for the Cu2ZnSnS4 devices.

Synthesis, characterization and photocatalytic activity of ZnO-SnO2 nanocomposites

International Nuclear Information System (INIS)

Hamrouni, Abdessalem; Lachheb, Hinda; Houas, Ammar

2013-01-01

Highlights: • ZnO-SnO 2 photocatalysts were prepared successfully by the coprecipitation method. • The best conditions found are: calcination at 600 °C/2 h; molar ratio Zn/Sn = 1/0.05. • The lower tin content in the samples led to the higher photocatalytic activity. • Zn-Sn 0.05 photoactivity under solar light was better than visible lamps light. -- Abstract: Nanocomposites of coupled ZnO-SnO 2 photocatalysts were synthesized by the coprecipitation method and were characterized by X-ray diffraction, UV–vis diffuse reflectance spectroscopy, surface area analyzer and scanning electron microscopy. Their photocatalytic activity was investigated under UV, visible and solar light and evaluated using methylene blue (MB) as a model pollutant. The performance of the coupled ZnO-SnO 2 photocatalysts was found to be related to the Zn/Sn molar ratio and to the calcination conditions. The photocatalyst with a Zn/Sn molar ratio of 1:0.05 calcined at 600 °C for 2 h showed the maximum degradation rate of MB under different lights used. Its photocatalytic activity was found to be about two times that of ZnO and about 10 times that of SnO 2 which can be explained by the heterojunction effect. Charge separation mechanism has been studied

ZnO as dielectric for optically transparent non-volatile memory

International Nuclear Information System (INIS)

Salim, N. Tjitra; Aw, K.C.; Gao, W.; Wright, Bryon E.

2009-01-01

This paper discusses the application of a DC sputtered ZnO thin film as a dielectric in an optically transparent non-volatile memory. The main motivation for using ZnO as a dielectric is due to its optical transparency and mechanical flexibility. We have established the relationship between the electrical resistivity (ρ) and the activation energy (E a ) of the electron transport in the conduction band of the ZnO film. The ρ of 2 x 10 4 -5 x 10 7 Ω-cm corresponds to E a of 0.36-0.76 eV, respectively. The k-value and optical band-gap for films sputtered with Ar:O 2 ratio of 4:1 are 53 ± 3.6 and 3.23 eV, respectively. In this paper, the basic charge storage element for a non-volatile memory is a triple layer dielectric structure in which a 50 nm thick ZnO film is sandwiched between two layers of methyl silsesquioxane sol-gel dielectric of varying thickness. A pronounced clockwise capacitance-voltage (C-V) hysteresis was observed with a memory window of 6 V. The integration with a solution-processable pentacene, 13,6-N-Sulfinylacetamodipentacene resulted in an optically transparent organic field effect transistor non-volatile memory (OFET-NVM). We have demonstrated that this OFET-NVM can be electrically programmed and erased at low voltage (± 10 V) with a threshold voltage shift of 4.0 V.

Controllable synthesis of ZnO nanograss with different morphologies and enhanced performance in dye-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Zhu Shibu; Chen Xiangnan; Zuo Feibiao; Jiang Man [Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Zhou Zuowan, E-mail: zwzhou@at-c.net [Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Hui, David [Department of Mechanical Engineering, University of New Orleans, New Orleans, LA 70148 (United States)

2013-01-15

A series of ZnO nanograss films grown on fluorine-doped tin oxide coated glass substrates were synthesized via hydrothermal method by using polyethyleneimine (PEI) as adjusting agent. The films were characterized by field emission scanning electron microscope (FE-SEM) and X-ray diffraction (XRD). It was found that the PEI not only affected the aspect ratios of ZnO nanograss but also changed the geometrical shape of ZnO nanograss. A possible mechanism based on PEI adsorbed on the non-polar facets of ZnO that governed the growth rate of different directions were proposed to elucidate the effect of PEI on morphology of ZnO. The ZnO nanograss films were applied to dye-sensitized solar cells (DSSCs). The results showed that the photocurrent density significantly enhanced, and the power conversion efficiency increased by 55% based on ZnO nanograss synthesized in a growth solution containing 7 mmol/L PEI, resulting from the dye loading properties related to the different morphologies. - Graphical abstract: Effect of PEI on ZnO nanograss: controlling the aspect ratio and morphology of ZnO and enhancing their photovoltaic performance. Highlights: Black-Right-Pointing-Pointer ZnO nanograss with different aspect ratios were synthesized by adjusting PEI content. Black-Right-Pointing-Pointer PEI affects both on the aspect ratios and geometrical shapes of ZnO nanograss. Black-Right-Pointing-Pointer ZnO nanograss with high aspect ratio and needle-like tip was advantageous for improved photovoltaic conversion performance.

Stable isotope and trace element status of subsistence-hunted bowhead and beluga whales in Alaska and gray whales in Chukotka

Energy Technology Data Exchange (ETDEWEB)

Dehn, Larissa-A. [Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775-7000 (United States)]. E-mail: ftld@uaf.edu; Follmann, Erich H. [Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775-7000 (United States); Rosa, Cheryl [Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775-7000 (United States); Duffy, Lawrence K. [Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775-7000 (United States); Thomas, Dana L. [Department of Mathematical Sciences, University of Alaska Fairbanks, Fairbanks, AK 99775-6660 (United States); Bratton, Gerald R. [Department of Veterinary Anatomy and Public Health, Texas A and M University, College Station, TX 77843 (United States); Taylor, Robert J. [Department of Veterinary Anatomy and Public Health, Texas A and M University, College Station, TX 77843 (United States); O' Hara, Todd M. [Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775-7000 (United States); Department of Wildlife Management, North Slope Borough, Barrow, AK 99725 (United States)

2006-03-15

Tissues of bowhead, beluga, and gray whales were analyzed for Ag, Cd, Cu, Se, Zn, THg and MeHg (belugas only). {delta}{sup 15}N and {delta}{sup 13}C in muscle were used to estimate trophic position and feeding habitat, respectively. Trace element concentrations in tissues were significantly different among whale species. Hepatic Ag was higher in belugas than bowheads and gray whales. Gray whales had lower Cd concentrations in liver and kidney than bowhead and belugas and a sigmoid correlation of Cd with length was noted for all whales. Renal and hepatic Se and THg were higher in belugas than in baleen whales. The hepatic molar ratio of Se:THg exceeded 1:1 in all species and was negatively correlated to body length. Hepatic and renal Zn in subsistence-harvested gray whales was lower than concentrations for stranded whales. Se:THg molar ratios and tissue concentrations of Zn may show promise as potential indicators of immune status and animal health.

Stable isotope and trace element status of subsistence-hunted bowhead and beluga whales in Alaska and gray whales in Chukotka

International Nuclear Information System (INIS)

Dehn, Larissa-A.; Follmann, Erich H.; Rosa, Cheryl; Duffy, Lawrence K.; Thomas, Dana L.; Bratton, Gerald R.; Taylor, Robert J.; O'Hara, Todd M.

2006-01-01

Tissues of bowhead, beluga, and gray whales were analyzed for Ag, Cd, Cu, Se, Zn, THg and MeHg (belugas only). δ 15 N and δ 13 C in muscle were used to estimate trophic position and feeding habitat, respectively. Trace element concentrations in tissues were significantly different among whale species. Hepatic Ag was higher in belugas than bowheads and gray whales. Gray whales had lower Cd concentrations in liver and kidney than bowhead and belugas and a sigmoid correlation of Cd with length was noted for all whales. Renal and hepatic Se and THg were higher in belugas than in baleen whales. The hepatic molar ratio of Se:THg exceeded 1:1 in all species and was negatively correlated to body length. Hepatic and renal Zn in subsistence-harvested gray whales was lower than concentrations for stranded whales. Se:THg molar ratios and tissue concentrations of Zn may show promise as potential indicators of immune status and animal health

Determination of the number density of excited and ground Zn atoms during rf magnetron sputtering of ZnO target

Energy Technology Data Exchange (ETDEWEB)

Maaloul, L.; Gangwar, R. K.; Stafford, L., E-mail: luc.stafford@umontreal.ca [Département de Physique, Université de Montréal, Montréal, Québec H3C 3J7 (Canada)

2015-07-15

A combination of optical absorption spectroscopy (OAS) and optical emission spectroscopy measurements was used to monitor the number density of Zn atoms in excited 4s4p ({sup 3}P{sub 2} and {sup 3}P{sub 0}) metastable states as well as in ground 4s{sup 2} ({sup 1}S{sub 0}) state in a 5 mTorr Ar radio-frequency (RF) magnetron sputtering plasma used for the deposition of ZnO-based thin films. OAS measurements revealed an increase by about one order of magnitude of Zn {sup 3}P{sub 2} and {sup 3}P{sub 0} metastable atoms by varying the self-bias voltage on the ZnO target from −115 to −300 V. Over the whole range of experimental conditions investigated, the triplet-to-singlet metastable density ratio was 5 ± 1, which matches the statistical weight ratio of these states in Boltzmann equilibrium. Construction of a Boltzmann plot using all Zn I emission lines in the 200–500 nm revealed a constant excitation temperature of 0.33 ± 0.04 eV. In combination with measured populations of Zn {sup 3}P{sub 2} and {sup 3}P{sub 0} metastable atoms, this temperature was used to extrapolate the absolute number density of ground state Zn atoms. The results were found to be in excellent agreement with those obtained previously by actinometry on Zn atoms using Ar as the actinometer gas [L. Maaloul and L. Stafford, J. Vac. Sci. Technol., A 31, 061306 (2013)]. This set of data was then correlated to spectroscopic ellipsometry measurements of the deposition rate of Zn atoms on a Si substrate positioned at 12 cm away from the ZnO target. The deposition rate scaled linearly with the number density of Zn atoms. In sharp contrast with previous studies on RF magnetron sputtering of Cu targets, these findings indicate that metastable atoms play a negligible role on the plasma deposition dynamics of Zn-based coatings.

Highly stabilized and photoluminescence enhancement of ZnS:Mn2+ nanoparticles in biotin matrix

International Nuclear Information System (INIS)

Keshari, Ashish K.; Pandey, Avinash C.

2009-01-01

We synthesized the ZnS:Mn 2+ nanoparticles passivated by biocompatible layer, namely, biotin by chemical precipitation route and studied their temporal evolution for size, structure, optical, and photoluminescence stability. To monitor the structural and optoelectronic properties of the nanoparticles with time, we have characterized the grown product by x-ray diffraction, small angle x-ray scattering, UV visible, and photoluminescence spectroscopic techniques at a regular interval for a period of three months. Results showed that the properties of nanophosphors capped with biotin are remaining the same even after 3 months. Energy dispersive x-ray analysis of 3 month aged sample shows long time compatibility between ZnS:Mn 2+ nanoparticles and the biotin. This is also confirmed by electron microscopy that the growth of the nanoparticles is strongly arrested by the biotin. X-ray photoelectron spectra were also recorded to show the chemical state of the elements. Enhanced ratio of Zn 2p to Mn 2p peaks in the x-ray photoelectron spectra of ZnS:Mn 2+ nanoparticles shows that the Mn 2+ ions are incorporated within ZnS host matrix. We found that biotin capping will enhance the luminescence from ZnS:Mn 2+ nanoparticles as compared to without capped particles. Absence of biotin will gradually degrade the luminescence upon aging while drastic degradation in luminescence intensity was observed after annealing. Properties show that biotin also protected the nanoparticles from any environmental attack

First-principles calculations of vacancy formation in In-free photovoltaic semiconductor Cu2ZnSnSe4

International Nuclear Information System (INIS)

Maeda, Tsuyoshi; Nakamura, Satoshi; Wada, Takahiro

2011-01-01

To quantitatively evaluate the formation energies of Cu, Zn, Sn, and Se vacancies in kesterite-type Cu 2 ZnSnSe 4 (CZTSe), first-principles pseudopotential calculations using plane-wave basis functions were performed. The formation energies of neutral Cu, Zn, Sn and Se vacancies were calculated as a function of the atomic chemical potentials of constituent elements. The obtained results were as follows: (1) the formation energy of Cu vacancy was generally smaller than those of the other Zn, Sn and Se vacancies, (2) under the Cu-poor and Zn-rich condition, the formation energy of Cu vacancy was particularly low, (3) the formation energy of Zn vacancy greatly depended on the chemical potentials of the constituent elements and under the Zn-poor and Se-rich condition, the formation energy of Zn vacancy was smaller than that of Cu vacancy, and (4) the formation energy of Sn vacancy did not greatly depend on the chemical potentials of the constituent elements and was much larger than those of Cu, Zn, and Se vacancies. These results indicate that Cu vacancy is easily formed under Cu-poor and Zn-rich conditions, but Zn vacancy is easily formed under the Zn-poor and Se-rich conditions.

Piezoelectricity and charge trapping in ZnO and Co-doped ZnO thin films

Directory of Open Access Journals (Sweden)

Domenico D’Agostino

2017-05-01

Full Text Available Piezoelectricity and charge storage of undoped and Co-doped ZnO thin films were investigated by means of PiezoResponse Force Microscopy and Kelvin Probe Force Microscopy. We found that Co-doped ZnO exhibits a large piezoelectric response, with the mean value of piezoelectric matrix element d33 slightly lower than in the undoped sample. Moreover, we demonstrate that Co-doping affects the homogeneity of the piezoelectric response, probably as a consequence of the lower crystalline degree exhibited by the doped samples. We also investigate the nature of the interface between a metal electrode, made up of the PtIr AFM tip, and the films as well as the phenomenon of charge storage. We find Schottky contacts in both cases, with a barrier value higher in PtIr/ZnO than in PtIr/Co-doped ZnO, indicating an increase in the work function due to Co-doping.

Characteristics of ZnO/diamond thin films prepared by RF magnetron sputtering

CERN Document Server

Park, Y W; Lee, J G; Baik, Y J; Kim, H J; Jung, H J; Choi, W K; Cho, B H; Park, C Y

1999-01-01

Due to its high Young's modulus, diamond has the highest acoustic wave velocity among all materials and is expected to be a candidate substrate for high-frequency surface acoustic wave(SAW) devices. In this study, the deposition of ZnO, as a piezoelectric layer, on a diamond substrate is investigated. ZnO has been fabricated by using RF magnetron sputtering with a ZnO target and various Ar/O sub 2 gas ratios, RF powers, and substrate temperatures at a vacuum of 10 sup - sup 5 Torr. The sputtered ZnO films are characterized by X-ray diffraction (XRD), Rutherford backscattering spectroscopy (RBS), X-ray photoelectron spectroscopy (XPS), and I-V characteristics. All the films show only a (002) orientation. The atomic concentration of the sputtered ZnO films is changed by the oxygen gas ratio, and the ZnO films are grown with a homogeneous composition over their entire thickness. The electrical resistivity of the films varied from 4x10 sup 3 to 7x10 sup 8 OMEGA cm, depending on the Ar/O sub 2 gas ratio. The phase...

Neutron Activation Resonance Integrals of 64Zn, 68Zn, 85Rb, 100Mo, 102Ru, 113In, 123Sb, and 180Hf

International Nuclear Information System (INIS)

Ricabarra, M. D.; Turjanski, R.; Ricabarra, G. H.

1969-01-01

The ratio of resonance integral to thermal activation cross sections of the isotopes 64 Zn, 68 Zn, 85 Rb, 100 Mo, 102 Ru, 113 In, 123 Sb, and 180 Hf relative to gold has been determined by measuring cadmium ratios. The standard gold or a secondary standard was mixed uniformly in the samples and the activities resolved with a lithium-drift germanium γ-ray spectrometer. Expressed as Westcott S 0 values the results were: 64 Zn = 2.06 ± 0.03, 68 Zn = 3.72 ± 0.14, 85 Rb = 18.4 ± 0.6, 100 Mo = 21.7 ± 0.8, 102 Ru = 3.76 ± 0.03, 113 In = 24.7 ± 0.5, 123 Sb = 28.3 ± 2.1, 180 Hf = 2.17 ± 0.09. All measurements are relative to S 0 = 17.7 for gold. (author)

The first principles study of elastic and thermodynamic properties of ZnSe

Science.gov (United States)

Khatta, Swati; Kaur, Veerpal; Tripathi, S. K.; Prakash, Satya

2018-05-01

The elastic and thermodynamic properties of ZnSe are investigated using thermo_pw package implemented in Quantum espresso code within the framework of density functional theory. The pseudopotential method within the local density approximation is used for the exchange-correlation potential. The physical parameters of ZnSe bulk modulus and shear modulus, anisotropy factor, Young's modulus, Poisson's ratio, Pugh's ratio and Frantsevich's ratio are calculated. The sound velocity and Debye temperature are obtained from elastic constant calculations. The Helmholtz free energy and internal energy of ZnSe are also calculated. The results are compared with available theoretical calculations and experimental data.

Hybrid Organic/ZnO p-n Junctions with n-Type ZnO Grown by Atomic Layer Deposition

Science.gov (United States)

Łuka, G.; Krajewski, T.; Szczerbakow, A.; Łusakowska, E.; Kopalko, K.; Guziewicz, E.; Wachnicki, Ł.; Szczepanik, A.; Godlewski, M.; Fidelus, J. D.

2008-11-01

We report on fabrication of hybrid inorganic-on-organic thin film structures with polycrystalline zinc oxide films grown by atomic layer deposition technique. ZnO films were deposited on two kinds of thin organic films, i.e. pentacene and poly(dimethylosiloxane) elastomer with a carbon nanotube content (PDMS:CNT). Surface morphology as well as electrical measurements of the films and devices were analyzed. The current density versus voltage (I-V) characteristics of ITO/pentacene/ZnO/Au structure show a low-voltage switching phenomenon typical of organic memory elements. The I-V studies of ITO/PDMS:CNT/ZnO/Au structure indicate some charging effects in the system under applied voltages.

NAA analysis of enriched Zn-68 by

International Nuclear Information System (INIS)

Rafii, H.; Mirzaei, M.; Mirzajani, N.; Sardari, D.; Shahabi, I.; Majedi, F.

2002-01-01

Excessive application of enriched isotopes in various fields of sciences and industry necessitates measuring their abundant by a precise and rapid methos. Beside the inductively coupled plasma mass spectrometry, the thermal neutron activation analysis, NAA, is an alternative method, which is capable to determine trace amounts of elements as well as the elemental abundance. In this article the enrichment of Zn-68 in two different samples has been studied by mean of NAA. One sample was separated by an electromagnetic system in our center and the other was purchased from a French company, Cortecnet. The neutron irradiation was took place in MNSR reactor by flux 10 1 1n/cm 2 sec. for 30 min. and the produced radioactivity from Zn-69 m was measured one day after irradiation by HPGe detector. The results shows a good agreement with the reported ones and its low derivation of about ±3.05 indicates that the NAA is a precise, rapid, and supplemental method for analyzing enriched Zn-68

Content, distribution and fate of 33 elements in sediments of rivers receiving wastewater in Hanoi, Vietnam

International Nuclear Information System (INIS)

Marcussen, Helle; Dalsgaard, Anders; Holm, Peter E.

2008-01-01

Untreated industrial and domestic wastewater from Hanoi city is discharged into rivers that supply water for various agricultural and aquacultural food production systems. The aim of this study was to assess the content, distribution and fate of 33 elements in the sediment and pore water of the main wastewater receiving rivers. The sediment was polluted with potentially toxic elements (PTEs) with maximum concentrations of 73 As, 427 Cd, 281 Cr, 240 Cu, 218 Ni, 363 Pb, 12.5 Sb and 1240 Zn mg kg -1 d.w. Observed distribution coefficients (log 10 K d,obs ) were calculated as the ratio between sediment (mg kg -1 d.w.) and pore water (mg L -1 ) concentrations. Maxima log 10 K d,obs were >4.26 Cd, >6.60 Cu, 4.78 Ni, 7.01 Pb and 6.62 Zn. The high values show a strong PTE retention and indicate the importance of both sorption and precipitation as retention mechanisms. Sulphide precipitation was a likely mechanism due to highly reduced conditions. - Sorption and precipitation processes are important in retention of potentially toxic elements in Hanoi river sediment and prevent elements entering food production systems

Multielement CdZnTe detectors for high-efficiency, ambient-temperature gamma-ray spectroscopy

International Nuclear Information System (INIS)

Prettyman, T.H.; Moss, C.E.; Sweet, M.R.; Ianakiev, K.; Reedy, R.C.; Li, J.; Valentine, J.D.

1998-01-01

CdZnTe is an attractive alternative to scintillator-based technology for ambient-temperature, gamma-ray spectroscopy. Large, single-element devices up to 3500 mm 3 have been developed for gamma-ray spectroscopy and are now available commercially. Because CdZnTe is a wide band-gap semiconductor, it can operate over a wide range of ambient temperatures with minimal power consumption. Over this range, CdZnTe detectors routinely yield better overall performance for gamma-ray spectroscopy than scintillator detectors. Manufacturing issues and material electronic properties limit the maximum size of single-element CdZnTe detectors. The authors are investigating methods to combine CdZnTe detectors together to improve detection efficiency and overall performance of gamma-ray spectroscopy. The applications include the assay and identification of radioisotopes for nuclear material safeguards and nonproliferation (over the energy range 50 keV to 1 MeV), and the analysis of elemental composition for planetary science (over the energy range 1 MeV to 10 MeV). Design issues for the two energy ranges are summarized

Elemental bioaccumulators in air pollution studies

International Nuclear Information System (INIS)

Freitas, M.C.

1995-01-01

K 0 -Based instrumental neutron activation analysis (k 0 INAA) was used to determine the concentrations of Cr, Fe, Co, Zn, Se, Sb and Hg in the vascular plants Cistus salvifolius and Inula viscosa and in the lichen Parmelia sulcata. The samples were collected in the neighbourhood of industrial complexes. The elemental accumulation in the vascular plants and the lichen are compared to optimize the choice of the bioaccumulator. It is concluded that P.sulcata seems to be the best accumulator of the three species for the element studied; Cistus salvifolius is sensitive to the contents of Zn, Fe, Cr and Sb in the air; Inula viscosa seems to accumulate Fe, Sb, Co, Cr and Zn. Nevertheless, it is concluded that lichen is a good air pollution indicator, while the vascular plants are not due to the large seasonal variations found in the elemental concentrations. (author) 11 refs.; 7 figs.; 2 tabs

Acceptor Type Vacancy Complexes In As-Grown ZnO

International Nuclear Information System (INIS)

Zubiaga, A.; Tuomisto, F.; Zuniga-Perez, J.

2010-01-01

One of the many technological areas that ZnO is interesting for is the construction of opto-electronic devices working in the blue-UV range as its large band gap (∼3.4 eV at 10 K) makes them suitable for that purpose. As-grown ZnO shows generally n-type conductivity partially due to the large concentration of unintentional shallow donors, like H, but impurities can also form complexes with acceptor type defects (Zn vacancy) leading to the creation of compensating defects. Recently, Li Zn and Na Zn acceptors have been measured and H could form similar type of defects. Doppler Broadening Positron Annihilation spectroscopy experimental results on the observation of Zn related vacancy complexes in ZnO thin films, as-grown, O implanted and Al doped will be presented. Results show that as-grown ZnO film show small Zn vacancy related complexed that could be related to presence of H as a unintentional doping element.

Influence of Dopants in ZnO Films on Defects

Science.gov (United States)

Peng, Cheng-Xiao; Weng, Hui-Min; Zhang, Yang; Ma, Xing-Ping; Ye, Bang-Jiao

2008-12-01

The influence of dopants in ZnO films on defects is investigated by slow positron annihilation technique. The results show S that parameters meet SAl > Sun > SAg for Al-doped ZnO films, undoped and Ag-doped ZnO films. Zinc vacancies are found in all ZnO films with different dopants. According to S parameter and the same defect type, it can be induced that the zinc vacancy concentration is the highest in the Al-doped ZnO film, and it is the least in the Ag-doped ZnO film. When Al atoms are doped in the ZnO films grown on silicon substrates, Zn vacancies increase as compared to the undoped and Ag-doped ZnO films. The dopant concentration could determine the position of Fermi level in materials, while defect formation energy of zinc vacancy strongly depends on the position of Fermi level, so its concentration varies with dopant element and dopant concentration.

Acceptor Type Vacancy Complexes In As-Grown ZnO

Science.gov (United States)

Zubiaga, A.; Tuomisto, F.; Zuñiga-Pérez, J.

2010-11-01

One of the many technological areas that ZnO is interesting for is the construction of opto-electronic devices working in the blue-UV range as its large band gap (˜3.4 eV at 10 K) makes them suitable for that purpose. As-grown ZnO shows generally n-type conductivity partially due to the large concentration of unintentional shallow donors, like H, but impurities can also form complexes with acceptor type defects (Zn vacancy) leading to the creation of compensating defects. Recently, LiZn and NaZn acceptors have been measured and H could form similar type of defects. Doppler Broadening Positron Annihilation spectroscopy experimental results on the observation of Zn related vacancy complexes in ZnO thin films, as-grown, O implanted and Al doped will be presented. Results show that as-grown ZnO film show small Zn vacancy related complexed that could be related to presence of H as a unintentional doping element.

Behaviors of chemical elements in the atmosphere, Kawasaki, Japan

International Nuclear Information System (INIS)

Oda, K.; Kikawada, Y.; Oi, T.

2008-01-01

A total of 19 elements in the samples of atmospheric deposition collected in Kawasaki, Japan, were determined by neutron activation analysis, ICPAES and flame photometry. The amounts of soil dust depositions were larger in springs and those of Sb and Zn depositions were larger in summers than in the other seasons. The values of the enrichment factors were higher for Sb and Zn than for the other elements determined throughout the sampling period. A factor analysis showed that the two elements were characterized as industrial components. Rubber products like tires that contain noncombustibles and rubber accelerators were a possible origin of high concentrations of Sb and Zn in the present samples. (author)

Tunable UV- and Visible-Light Photoresponse Based on p-ZnO Nanostructures/n-ZnO/Glass Peppered with Au Nanoparticles.

Science.gov (United States)

Hsu, Cheng-Liang; Lin, Yu-Hong; Wang, Liang-Kai; Hsueh, Ting-Jen; Chang, Sheng-Po; Chang, Shoou-Jinn

2017-05-03

UV- and visible-light photoresponse was achieved via p-type K-doped ZnO nanowires and nanosheets that were hydrothermally synthesized on an n-ZnO/glass substrate and peppered with Au nanoparticles. The K content of the p-ZnO nanostructures was 0.36 atom %. The UV- and visible-light photoresponse of the p-ZnO nanostructures/n-ZnO sample was roughly 2 times higher than that of the ZnO nanowires. The Au nanoparticles of various densities and diameter sizes were deposited on the p-ZnO nanostructures/n-ZnO samples by a simple UV photochemical reaction method yielding a tunable and enhanced UV- and visible-light photoresponse. The maximum UV and visible photoresponse of the Au nanoparticle sample was obtained when the diameter size of the Au nanoparticle was approximately 5-35 nm. On the basis of the localized surface plasmon resonance effect, the UV, blue, and green photocurrent/dark current ratios of Au nanoparticle/p-ZnO nanostructures/n-ZnO are ∼1165, ∼94.6, and ∼9.7, respectively.

Structural characterization of CdSe/ZnS quantum dots using medium energy ion scattering

Science.gov (United States)

Sortica, M. A.; Grande, P. L.; Radtke, C.; Almeida, L. G.; Debastiani, R.; Dias, J. F.; Hentz, A.

2012-07-01

In the present work, we have analyzed CdSe/ZnS core-shell quantum dots by medium energy ion scattering (MEIS), which is a powerful technique to explore the synthesis, formation, stability, and elemental distribution of such core-shell structures, along with other auxiliary analytical techniques. By comparing different quantum-dot structural models spectra with the experimental MEIS data, we were able to obtain some sample structural information. We found that, despite the well known non stoichiometric Cd:Se ratio, the core is stoichiometric, and there is an excess of cadmium distributed in the shell.

Morphology, Structure and Nonstoichiometry of ZnCr2O4 Nanophased Powder

Directory of Open Access Journals (Sweden)

O. Milosevic

2003-10-01

Full Text Available It is well established that gas/humidity-sensing properties of spinels are markedly influenced by their stoichiometry and microstructure. In this work nucleation and spinel phase development in the Zn-Cr-O system were investigated from the viewpoint of structural and morphological phenomena occurred during nanophased particle synthesis through aerosol reaction. The aerosol was generated from nitrates precursor solution using ultrasonic atomizer operated at 1.7 MHz. The influence of different decomposition schedules on the particle chemical content and morphology was determined by adjusting the processing parameters (aerosol droplet density 3.9x106 droplets/cm3, droplet velocity 0.035m/s, max. temperature 900oC and residence times 3, 6 and 9s. A composite particle structure comprised of primary crystallites sized from 22 to 44nm is revealed by SEM and TEM analysis. XRD structural analysis (crystallite size, microstrains, unit cell and ionic occupancies is performed in accordance with procedure based on Koalariet-Xfit program. A certain degree of non-stochiometry is characteristic for all powders. Homogenous distribution of the constituting elements and Zn/Cr ratio of about 0.68 are proved by EDAX mapping analysis in 470nm sized as-prepared particles. After additional treatment at 1000oC octahedral crystals form with the (111 surface dominat. Evaluated spinel non-stochiometry (Zn/Cr=0.58 is a result of the ZnO dissolving (1.9%wt in the stoichiometric ZnCr2O4. Determination of the way by which the ZnO is incorporated into the spinel lattice is performed according to the procedure based on calculation of both formation and attachment energies.

Determination of trace elements in chicken feeds in Khartoum state

International Nuclear Information System (INIS)

Hassan, Salma Yahya Mohammed

2017-03-01

Trace elements are very important for chicken because thy contribute in biochemical processes required for normal growth, development and formation of the eggshell. The deficiency or the elevation of these trace elements may affect the normal physiological activity and biochemical process of their bodies. In this study the concentrations of trace elements in chicken feed samples were determined by X RF spectrometry. The results showed that there were 9 trace elements in sample ( K, Ca Mn, Fe Cu Zn, Pb, Rb, Sr) the mean concentration were K ( 2.12 x 10 4 ), Ca (2.22x10 4 ), Mn (48.1). Fe (191), Cu(9.81), Zn (24.6), Pb (1.63), Rb (7.79), Sr(4.09) ppm. Comparing the trace elements concentrations obtained in this study with the recommended values showed that some of them e.g Mn, Cu, Zn, Fe were found higher concentration than the recommended values, which stipulated by national research council NRC European Union. While lead concentration was in the permissible limit (5mg/kg). However, the statistical Alan's revealed than there were no significant difference between all concentrations of trace elements in the two types of chicken feeds i.e layer and broiler. The pearson correlation test displayed a strong correlation between K-Rb (0.885), Mn-Zn (0.874). The negative correlation between Mn-Rb (0.680), K-Mn (0.6000), K-Ca (0.565), Zn-Rb (-0.541). Ca-Rb (0.458) were found . Further investigations were performed using the principal component analysis (PCA) which involved the extraction of principal factor to study the total variance in the feed samples in terms of the trace elements concentrations in each. The obtained results revealed that the first principal component have a positive correlation with the elements Ca, Mn, Pb, and Zn, while K and Rb showed negative correlation with it. Similarly, the second principal compound showed positive correlation with the elements Mn, PB and Zn, while Ca and Sr showed negative, on the perth hand the third component was found to

Understanding corrosion behavior of Mg–Zn–Ca alloys from subcutaneous mouse model: Effect of Zn element concentration and plasma electrolytic oxidation

Energy Technology Data Exchange (ETDEWEB)

Jang, Yongseok [Engineering Research Center for Revolutionizing Metallic Biomaterials (ERC-RMB), North Carolina A and T State University, Greensboro, NC 27411 (United States); Tan, Zongqing [Department of Internal Medicine, College of Medicine, University of Cincinnati, Cincinnati, OH 45221 (United States); Jurey, Chris [Luke Engineering, Wadsworth, OH 44282 (United States); Xu, Zhigang [Engineering Research Center for Revolutionizing Metallic Biomaterials (ERC-RMB), North Carolina A and T State University, Greensboro, NC 27411 (United States); Dong, Zhongyun [Department of Internal Medicine, College of Medicine, University of Cincinnati, Cincinnati, OH 45221 (United States); Collins, Boyce [Engineering Research Center for Revolutionizing Metallic Biomaterials (ERC-RMB), North Carolina A and T State University, Greensboro, NC 27411 (United States); Yun, Yeoheung, E-mail: yyun@ncat.edu [Engineering Research Center for Revolutionizing Metallic Biomaterials (ERC-RMB), North Carolina A and T State University, Greensboro, NC 27411 (United States); Sankar, Jagannathan [Engineering Research Center for Revolutionizing Metallic Biomaterials (ERC-RMB), North Carolina A and T State University, Greensboro, NC 27411 (United States)

2015-03-01

Mg–Zn–Ca alloys are considered as suitable biodegradable metallic implants because of their biocompatibility and proper physical properties. In this study, we investigated the effect of Zn concentration of Mg–xZn–0.3Ca (x = 1, 3 and 5 wt.%) alloys and surface modification by plasma electrolytic oxidation (PEO) on corrosion behavior in in vivo environment in terms of microstructure, corrosion rate, types of corrosion, and corrosion product formation. Microstructure analysis of alloys and morphological characterization of corrosion products were conducted using x-ray computed tomography (micro-CT) and scanning electron microscopy (SEM). Elemental composition and crystal structure of corrosion products were determined using x-ray diffraction (XRD) and electron dispersive x-ray spectroscopy (EDX). The results show that 1) as-cast Mg–xZn–0.3Ca alloys are composed of Mg matrix and a secondary phase of Ca{sub 2}Mg{sub 6}Zn{sub 3} formed along grain boundaries, 2) the corrosion rate of Mg–xZn–0.3Ca alloys increases with increasing concentration of Zn in the alloy, 3) corrosion rates of alloys treated by PEO sample are decreased in in vivo environment, and 4) the corrosion products of these alloys after in vivo tests are identified as brucite (Mg(OH){sub 2}), hydroxyapatite (Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}), and magnesite (MgCO{sub 3}·3H{sub 2}O). - Highlights: • Effects of PEO and Zn concentration in Mg–xZn–0.3Ca alloys on biodegradation • Corrosion rate of Mg–xZn–0.3Ca alloys increases with increasing Zn concentration. • Plasma electrolytic oxidation retards the biodegradation of Mg–xZn–0.3Ca alloys.

Using column experiments to examine transport of As and other trace elements released from poultry litter: Implications for trace element mobility in agricultural watersheds

International Nuclear Information System (INIS)

Oyewumi, Oluyinka; Schreiber, Madeline E.

2017-01-01

Trace elements are added to poultry feed to control infection and improve weight gain. However, the fate of these trace elements in poultry litter is poorly understood. Because poultry litter is applied as fertilizer in many agricultural regions, evaluation of the environmental processes that influence the mobility of litter-derived trace elements is critical for predicting if trace elements are retained in soil or released to water. This study examined the effect of dissolved organic carbon (DOC) in poultry litter leachate on the fate and transport of litter-derived elements (As, Cu, P and Zn) using laboratory column experiments with soil collected from the Delmarva Peninsula (Mid-Atlantic, USA), a region of intense poultry production. Results of the experiments showed that DOC enhanced the mobility of all of the studied elements. However, despite the increased mobility, 60–70% of Zn, As and P mass was retained within the soil. In contrast, almost all of the Cu was mobilized in the litter leachate experiments, with very little retention in soil. Overall, our results demonstrate that the mobility of As, Cu, Zn and P in soils which receive poultry litter application is strongly influenced by both litter leachate composition, specifically organic acids, and adsorption to soil. Results have implications for understanding fate and transport of trace elements released from litter application to soil water and groundwater, which can affect both human health and the environment. - Highlights: • Column experiments examined fate of trace elements derived from poultry litter leachate in soils from Delaware, USA. • Influent solutions included poultry litter leachate and simulated solution without DOC. • Results showed increased mobility of litter-derived As, Cu, Zn and P in solution in the presence of DOC. • Mass balance showed all of Cu mass remained in solution but most (60–70%) of the Zn, As and P mass was associated with soil. • Study results show that DOC

Tunable resistive switching behaviour in ferroelectric–ZnO bilayer films

International Nuclear Information System (INIS)

Zhou Mingxiu; Li Ziwei; Chen Bo; Wan Jianguo; Liu Junming

2013-01-01

Pb(Zr 0.52 Ti 0.48 )O 3 /ZnO bilayer films with various ZnO-layer thicknesses were prepared by a sol–gel process, and their phase structures, electric conduction and polarization behaviour were measured. The results showed that the preferential crystal orientation of the ZnO layer changed with a change in its thickness. The strong dependence of both asymmetric current–voltage and polarization–voltage characteristics on the ZnO-layer thickness was observed. The resistance ratio of the high-resistance state (HRS) to the low-resistance state (LRS) increased with increasing ZnO-layer thickness, and a high rectification ratio was obtained in the bilayer film with an optimized ZnO-layer thickness. The combined effects of interface polarization coupling and energy band structure on the resistive switching behaviour of the bilayer films were revealed, and the electric conduction mechanisms of the bilayer films at both HRS and LRS were analysed in detail. This work presents an effective method to modulate the resistive switching behaviour of ferroelectric–ZnO heterostructures, which is significant in designing high-performance ferroelectric–semiconductor heterostructures for actual applications. (paper)

Concentration of trace elements in marine organisms

International Nuclear Information System (INIS)

Ishii, Takaaki; Suzuki, Hamaji; Iimura, Mitsue; Koyanagi, Taku

1976-01-01

Information on the quality and quantity of stable trace elements in marine environments is frequently required to analyze the radioecological behavior of radionuclides released from nuclear facilities into the sea. In the present work, special attention was concentrated in determination of stable Mn, Fe, Co, Zn, Rb and Cs in marine organisms to estimate the concentration factors for these elements and corresponding radionuclides. Marine organisms (fishes, marine invertebrates and seaweeds) were collected at the seashore of Ibaragi prefecture and provided for chemical analysis after dry-ashing and wet-ashing. Atomic absorption spectrophotometry and neutron activation analysis were applied to determine the concentration of elements. The concentration of stable elements in fish muscle was independent on species of the fishes though slightly higher trends were observed in ''Usumebaru'', Sebastes nivosus for Cs, ''Ishimochi'', Nibea mitsukurii for Zn and Fe compared with other species. The concentration of Co, Zn and Fe in muscle of marine invertebrates was one order of magnitude higher than fish muscles especially in shellfishes for Co. Seaweeds showed peculiar species specificity for the concentration of stable trace elements and remarkable differences was observed between the species even among the same genus. (auth.)

Quantitative study of elemental inter-diffusion across ZnSe/GaAs interface by using SIMS

International Nuclear Information System (INIS)

Gard, F.S.; Riley, J.; Usher, B.F.; Prince, K.; Burke, P.

1999-01-01

ZnSe and related II-VI materials are wide bandgap semiconductors, which are expected to be used for blue/green lasers. However, the maximum lifetime of the devices has not been increased beyond 400 hours for the last 3 years. In this time commercial GaN-based devices have been successfully introduced to market. However GaN-based devices do not cover the whole range of green region, due to their bandgaps. Molecular Beam Epitaxy (MBE) of ZnSe-based materials has overcome some of the problems traditionally encountered in producing high-quality crystalline ZnSe. Controlled doping of ZnSe to produce n- and p- type material has made it possible to develop high efficiency pin diodes for use in the visible region. ZnSe-based materials still have a technological future, however remaining problems are yet to be solved. This paper present data obtained from ZnSe epilayers grown on GaAs substrates by MBE. At temperatures over 500 deg C diffusion og Ga atoms was clearly observed. The diffusion of As atoms was relatively small compared to the Ga atoms

A PIXE analysis for measuring the trace elements concentration in breast tissue of Iranian women

International Nuclear Information System (INIS)

Vatankhah, S.; Moosavi, K.; Salimi, J.; Geranpayeh, L.; Perovani, H.

2003-01-01

A powerful and improved technique, proton induced x-ray emission has been performed-yielding the elemental composition of 17 samples of surgically excised malignant and normal tumors of breast tissue. The samples without any further process as thick targets were put on cap ton foil backing. There are no homogenizing processes. The proton induced x-ray emission spectra analysis was performed using he non-linear least square fitting code AXIL and GUPIX. The samples are taken form patients in the wide range of age and are bombarded by 2.0 MeV energy proton beams produced by van de Graaff accelerator in vacuum. The quantitative comparison between two of tissue was evaluated by assessing the presence of calcium. Potassium, Iron, Copper and Zinc, as minor and trace elements. results in this study indicate that relative values of Cu/Zn, P/K and also Ca and S in being type were higher than those in those in malignant type, but the concentration of Fe and Zn in cancerous tissues was significantly higher than those for being type. Results suggest significant elevation of zinc in the pathological tissues. Cu/Zn ratio for both type of tissues are evaluated. The results show that this ratio in patients with breast cancer is significantly lower than the normal group. Selenium and arsenic was not obtained in any of 17 samples. Most of the tissues of benign kind (fibrocystic and fib ro adenoma)contain cadmium. Calcium concentration in normal tissues is significantly higher than tumorous tissues

Vapour transport growth of ZnO nanorods

Energy Technology Data Exchange (ETDEWEB)

Mofor, A.C.; Bakin, A.S.; Elshaer, A.; Waag, A. [Technical University Braunschweig, Institute of Semiconductor Technology, Braunschweig (Germany); Fuhrmann, D.; Hangleiter, A. [Technical University Braunschweig, Institute of Applied Physics, Braunschweig (Germany); Bertram, F.; Christen, J. [University of Magdeburg, Department of Solid State Physics, Magdeburg (Germany)

2007-07-15

The fabrication of low-dimensional ZnO structures has attracted enormous attention as such nanostructures are expected to pave the way for many interesting applications in optoelectronics, spin electronics gas sensor technology and biomedicine. Many reported fabrication methods, especially for ZnO nanorods are mostly based on catalyst-assisted growth techniques that employ metal-organic sources and other contaminating agents like graphite to grow ZnO nanorods at relatively high temperatures. We report on catalyst-free vapour-phase epitaxy growth of ZnO nanorods on 6H-SiC and (11-20)Al{sub 2}O{sub 3} using purely elemental sources at relatively low temperatures and growth pressure. ZnO nanorods with widths of 80-900 nm and lengths of up to 12 {mu}m were obtained. Nanorod density on the order of 10{sup 9} cm{sup -2} with homogenous luminescence and high purity was also noted. (orig.)

Positron annihilation studies in ZnO nanoparticles

Science.gov (United States)

Sharma, S. K.; Pujari, P. K.; Sudarshan, K.; Dutta, D.; Mahapatra, M.; Godbole, S. V.; Jayakumar, O. D.; Tyagi, A. K.

2009-04-01

We report results on positron annihilation spectroscopic (PAS) studies using lifetime and coincidence Doppler broadening techniques in zinc oxide (ZnO) nanoparticles (4 to 40 nm) synthesized by solid state pyrolytic reaction followed by annealing in the temperature range of 200 ∘C to 800 ∘C. Positron lifetime in the nanoparticles are observed to be higher than bulk lifetime in all the cases. Theoretical calculation of lifetime indicates the presence of either Zn or (Zn, O) vacancy clusters which migrate and anneal out at high temperature. Comparison of ratio spectra from coincidence Doppler broadening measurement and calculated electron momentum distribution indicates the presence of either Zn or (Zn, O) vacancies. In addition, photoluminescence (PL) measurements have been carried out to examine the role of defects on the intensity of emission in the visible region.

Power-dependent photocatalytic activity of ZnO

Energy Technology Data Exchange (ETDEWEB)

Chun, So Yeon; Han, Noh Soo; Jeong, Seong Hyun; Park, Seung Min; Song, Jae Kyu [Dept. of Chemistry, Kyung Hee University, Seoul (Korea, Republic of); Moon, Cheol Joo; Choi, Myong Yong [Dept. of Chemistry (BK21) and Research Institute of Natural Science, Gyeongsang NationalUniversity, Jinju (Korea, Republic of)

2017-03-15

the power-dependent photocatalytic activity of ZnO was examined for the photoreduction processes of Rh101 and AN in the presence of hole scavengers, where the fluorescence spectra were measured as a function of irradiation time and excitation intensity. The concentration of the reactants decreased, while the concentration of the products increased accordingly, which indicated the single-electron reduction process by electrons supplied from the conduction band of ZnO. Despite the single-electron process, the efficiency of the photoreaction depended nonlinearly on the excitation intensity, which was explained by the saturation of defect states in ZnO. The enhanced ratio of available electrons in ZnO led to a superlinear increase in the photoreduction efficiency, while the single-electron process linearly reflected the electrons available in ZnO.

Zinc: a multipurpose trace element

Energy Technology Data Exchange (ETDEWEB)

Stefanidou, M.; Maravelias, C.; Dona, A.; Spiliopoulou, C. [University of Athens, Department of Forensic Medicine and Toxicology, Athens (Greece)

2006-01-01

Zinc (Zn) is one of the most important trace elements in the body and it is essential as a catalytic, structural and regulatory ion. It is involved in homeostasis, in immune responses, in oxidative stress, in apoptosis and in ageing. Zinc-binding proteins (metallothioneins, MTs), are protective in situations of stress and in situations of exposure to toxic metals, infections and low Zn nutrition. Metallothioneins play a key role in Zn-related cell homeostasis due to their high affinity for Zn, which is in turn relevant against oxidative stress and immune responses, including natural killer (NK) cell activity and ageing, since NK activity and Zn ion bioavailability decrease in ageing. Physiological supplementation of Zn in ageing and in age-related degenerative diseases corrects immune defects, reduces infection relapse and prevents ageing. Zinc is not stored in the body and excess intakes result in reduced absorption and increased excretion. Nevertheless, there are cases of acute and chronic Zn poisoning. (orig.)

Chelating resin immobilizing carboxymethylated polyethyleneimine for selective solid-phase extraction of trace elements: Effect of the molecular weight of polyethyleneimine and its carboxymethylation rate.

Science.gov (United States)

Kagaya, Shigehiro; Kajiwara, Takehiro; Gemmei-Ide, Makoto; Kamichatani, Waka; Inoue, Yoshinori

2016-01-15

The effect of the molecular weight of polyethyleneimine (PEI), defined as a compound having two or more ethyleneamine units, and of its carboxymethylation rate (CM/N), represented by the ratio of ion-exchange capacity to the amount of N on the resin, on the selective solid-phase extraction ability of the chelating resin immobilizing carboxymethylated (CM) PEI was investigated. The chelating resins (24 types) were prepared by immobilization of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, PEI300 (MW=ca. 300), and PEI600 (MW=ca. 600) on methacrylate resins, followed by carboxymethylation with various amounts of sodium monochloroacetate. When resins with approximately the same CM/N ratio (0.242-0.271) were used, the recovery of Cd, Co, Cu, Fe, Ni, Pb, Ti, Zn, and alkaline earth elements increased with increasing the molecular weight of PEIs under acidic and weakly acidic conditions; however, the extraction behavior of Mo and V was only slightly affected. This was probably due to the increase in N content of the resin, resulting in an increase in carboxylic acid groups; the difference in the molecular weight of PEIs immobilized on the resin exerts an insignificant influence on the selective extraction ability. The CM/N ratio considerably affected the extraction behavior for various elements. Under acidic and neutral conditions, the recovery of Cd, Co, Cu, Fe, Ni, Pb, Ti, and Zn increased with increasing CM/N values. However, under these conditions, the recovery of alkaline earth elements was considerably low when a resin with low CM/N ratio was used. This is presumably attributed to the different stability constants of the complexes of these elements with aminocarboxylic acids and amines, and to the electrostatic repulsion between the elements and the protonated amino groups in the CM-PEI. The recovery of Mo and V decreased or varied with increasing CM/N values, suggesting that the extraction of these elements occurred mainly

Trace element analysis in soy sauce

International Nuclear Information System (INIS)

Haruyama, Yoichi; Saito, Manabu; Tomiya, Michio

1993-01-01

Trace elements in soy sauce have been measured by means of in-air PIXE. Six kinds of trace elements were detected, such as Mn, Fe, Ni, Zn, Cu and Br. Concentrations of Mn, Fe, Zn and Br which were observed in all samples, have been determined. Each analyzed sample contained considerable amount of Br about 160 ppm. Comparison of Br content of the imported raw materials with those of the domestic ones suggested that the large amount of Br was the residual fumigation chemicals in the imported raw materials. (author)

Metallic elements (Ca, Hg, Fe, K, Mg, Mn, Na, Zn) in the fruiting bodies of Boletus badius.

Science.gov (United States)

Kojta, Anna K; Falandysz, Jerzy

2016-06-01

The aim of this study was to investigate and compare the levels of eight metallic elements in the fruiting bodies of Bay Bolete (Boletus badius; current name Imleria badia) collected from ten sites in Poland to understand better the value of this popular mushroom as an organic food. Bay Bolete fruiting bodies were collected from the forest area near the towns and villages of Kętrzyn, Poniatowa, Bydgoszcz, Pelplin, Włocławek, Żuromin, Chełmno, Ełk and Wilków communities, as well as in the Augustów Primeval Forest. Elements such as Ca, Fe, K, Mg, Mn, Na and Zn were analyzed by inductively coupled plasma atomic emission spectroscopy (ICP-OES), and mercury by cold vapor atomic absorption spectrometry (CV-AAS). This made it possible to assess the nutritional value of the mushroom, as well as possible toxicological risks associated with its consumption. The results were subjected to statistical analysis (Kruskal-Wallis test, cluster analysis, principal component analysis). Copyright © 2016 Elsevier Ltd. All rights reserved.

The role of Al, Ba, and Cd dopant elements in tailoring the properties of c-axis oriented ZnO thin films

Energy Technology Data Exchange (ETDEWEB)

Ali, Dilawar [Department of Physics GC University, Lahore 54000 (Pakistan); Center for Advanced Studies in Physics, GC University Lahore, Lahore 54000 (Pakistan); Butt, M.Z., E-mail: mzakriabutt@gmail.com [Center for Advanced Studies in Physics, GC University Lahore, Lahore 54000 (Pakistan); Arif, Bilal [Department of Physics, Faculty of Arts and Sciences, Firat University, 23169 Elazig (Turkey); Al-Ghamdi, Ahmed A. [Department of Physics, Faculty of Sciences, King Abdul Aziz University, Jeddah (Saudi Arabia); Yakuphanoglu, Fahrettin [Department of Physics, Faculty of Arts and Sciences, Firat University, 23169 Elazig (Turkey); Department of Physics, Faculty of Sciences, King Abdul Aziz University, Jeddah (Saudi Arabia)

2017-02-01

Highly c-axis oriented un-doped ZnO and Al-, Ba-, and Cd-doped ZnO thin films were successfully deposited on glass substrate employing sol-gel spin coating method. XRD analysis showed that all thin films possess hexagonal wurtzite structure with preferred orientation along c-axis. Field emission scanning electron microscope (FESEM) was used to study the morphology of thin films. The morphology consists of spherical and non-spherical shape grains. EDX analysis confirms the presence of O, Zn, Al, Ba, and Cd in the relevant thin films. The optical properties of thin films were studied using UV–Vis spectrometer. All thin films possess more than 85% optical transmittance in the visible region. Blue shift in optical band gap E{sub g} has been observed on doping with Al, whereas doping with Ba and Cd resulted in red shift of E{sub g}. Urbach energy E{sub u} of all doped ZnO thin films was found to have excellent correlation with their band gap energy E{sub g}. Moreover, E{sub g} increases while E{sub u} decreases on the increase in crystallite size D. Optical parameters E{sub g} and E{sub u} as well as structural parameters lattice strain and stacking fault probability also show excellent correlation with the B-factor or the mean-square amplitude of atomic vibrations of the dopant elements. Electrical conductivity measurement of the thin films was carried out using two-point probe method. The electrical conductivity was found to increase with the increase in crystallite orientation along c-axis.

Simultaneous increase in strength and ductility by decreasing interface energy between Zn and Al phases in cast Al-Zn-Cu alloy.

Science.gov (United States)

Han, Seung Zeon; Choi, Eun-Ae; Park, Hyun Woong; Lim, Sung Hwan; Lee, Jehyun; Ahn, Jee Hyuk; Hwang, Nong-Moon; Kim, Kwangho

2017-09-22

Cast-Al alloys that include a high amount of the second element in their matrix have comparatively high strength but low ductility because of the high volume fraction of strengthening phases or undesirable inclusions. Al-Zn alloys that have more than 30 wt% Zn have a tensile strength below 300 MPa, with elongation under 5% in the as-cast state. However, we found that after substitution of 2% Zn by Cu, the tensile strength of as-cast Al-Zn-Cu alloys was 25% higher and ductility was four times higher than for the corresponding Al-35% Zn alloy. Additionally, for the Al-43% Zn alloy with 2% Cu after 1 h solution treatment at 400 °C and water quenching, the tensile strength unexpectedly reached values close to 600 MPa. For the Al-33% Zn alloy with 2% Cu, the tensile strength was 500 MPa with 8% ductility. The unusual trends of the mechanical properties of Al-Zn alloys with Cu addition observed during processing from casting to the subsequent solution treatment were attributed to the precipitation of Zn in the Al matrix. The interface energy between the Zn particles and the Al matrix decreased when using a solution of Cu in Zn.

A measuring system for the fast simultaneous isotope ratio and elemental analysis of carbon, hydrogen, nitrogen and sulfur in food commodities and other biological material.

Science.gov (United States)

Sieper, Hans-Peter; Kupka, Hans-Joachim; Williams, Tony; Rossmann, Andreas; Rummel, Susanne; Tanz, Nicole; Schmidt, Hanns-Ludwig

2006-01-01

The isotope ratio of each of the light elements preserves individual information on the origin and history of organic natural compounds. Therefore, a multi-element isotope ratio analysis is the most efficient means for the origin and authenticity assignment of food, and also for the solution of various problems in ecology, archaeology and criminology. Due to the extraordinary relative abundances of the elements hydrogen, carbon, nitrogen and sulfur in some biological material and to the need for individual sample preparations for H and S, their isotope ratio determination currently requires at least three independent procedures and approximately 1 h of work. We present here a system for the integrated elemental and isotope ratio analysis of all four elements in one sample within 20 min. The system consists of an elemental analyser coupled to an isotope ratio mass spectrometer with an inlet system for four reference gases (N(2), CO(2), H(2) and SO(2)). The combustion gases are separated by reversible adsorption and determined by a thermoconductivity detector; H(2)O is reduced to H(2). The analyser is able to combust samples with up to 100 mg of organic material, sufficient to analyse samples with even unusual elemental ratios, in one run. A comparison of the isotope ratios of samples of water, fruit juices, cheese and ethanol from wine, analysed by the four-element analyser and by classical methods and systems, respectively, yielded excellent agreements. The sensitivity of the device for the isotope ratio measurement of C and N corresponds to that of other systems. It is less by a factor of four for H and by a factor of two for S, and the error ranges are identical to those of other systems. Copyright (c) 2006 John Wiley & Sons, Ltd.

Transesterification of palm oil on K{sub y}Mg{sub 1} {sub -} {sub x}Zn{sub 1} {sub +} {sub x}O{sub 3} catalyst: Effect of Mg-Zn interaction

Energy Technology Data Exchange (ETDEWEB)

Olutoye, M.A.; Hameed, B.H. [School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia)

2010-06-15

The Mg-Zn interaction effect of K{sub y}Mg{sub 1} {sub -} {sub x}Zn{sub 1} {sub +} {sub x}O{sub 3} heterogeneous type catalyst and its performance on transesterification of palm oil have been studied using the response surface methodology and the factorial design of experiments. The catalyst was synthesized using the co-precipitation method and the activity was assessed by transesterification of palm oil into fatty acid methyl esters. The ratio of the Mg/Zn metal interaction, temperature and time of calcination were found to have positive influence on the conversion of palm oil to fatty acid methyl ester (FAME) with the effect of metal to metal ratio and temperature of calcination being more significant. The catalytic activity was found to decrease at higher calcination temperature and the catalyst type K{sub 2}Mg{sub 0.34}Zn{sub 1.66}O{sub 3} with Mg/Zn ratio of 4.81 gave FAME content of 73% at a catalyst loading of 1.404 wt.% of oil with molar ratio of methanol to oil being 6:1 at temperature of 150 C in 6 h. A regression model was obtained to predict conversions to methyl esters as a function of metal interaction ratio, temperature of calcination and time. The observed activity of the synthesized catalyst was due to its synergetic structure and composition. (author)

Population health risk via dietary exposure to trace elements (Cu, Zn, Pb, Cd, Hg, and As) in Qiqihar, Northeastern China.

Science.gov (United States)

Luo, Jinming; Meng, Jia; Ye, Yajie; Wang, Yongjie; Bai, Lin

2018-02-01

The estimated daily intakes (EDIs) of six trace elements (Cu, Zn, Pb, Cd, Hg, and As) in vegetables (leafy vegetable, i.e., bok choy, fruit vegetables, i.e., cucumber and tomato, and other categories, i.e., mushroom, kidney bean, and potato), cereals (rice and wheat flour), and meats (pork, mutton, and beef) most commonly consumed by adult inhabitants of Qiqihar, Northeastern China, were determined to assess the health status of local people. The average EDIs of Cu, Zn, Pb, Cd, Hg, and As were with 20.77 μg (kg bw) -1 day -1 of Cu, 288 μg (kg bw) -1 day -1 of Zn, 2.01 μg (kg bw) -1 day -1 of Pb, 0.41 μg (kg bw) -1 day -1 of Cd, 0.01 μg (kg bw) -1 day -1 of Hg, and 0.52 μg (kg bw) -1 day -1 of As, respectively, which are below the daily allowance recommended by FAO/WHO. However, the maximum EDIs of Pb and Cd were 4.56 μg (kg bw) -1 day -1 and 1.68 μg (kg bw) -1 day -1 , respectively, which are above the recommended levels [i.e., 3.58 μg (kg bw) -1 day -1 for Pb and 1.0 μg (kg bw) -1 day -1 for Cd] by FAO/WHO. This finding indicates that the potential health risk induced by daily ingestion of Pb and Cd for the local residents should receive a significant concern. Similarly, we detected elevated Pb and Cd concentrations, i.e., with average of 13.58 and 0.60 mg kg -1 dw, respectively, in the adult scalp hairs. Consumption of rice, potato, bok choy, and wheat flour contributed to 75 and 82% of Pb and Cd daily intake from foodstuffs. Nevertheless, human scalp hair is inappropriate biological material for determination of the nutritional status of trace elements in this region.

Effects of nitrogen and water addition on trace element stoichiometry in five grassland species

DEFF Research Database (Denmark)

Cai, Jiangping; Weiner, Jacob; Wang, Ruzhen

2017-01-01

A 9-year manipulative experiment with nitrogen (N) and water addition, simulating increasing N deposition and changing precipitation regime, was conducted to investigate the bioavailability of trace elements, iron (Fe), manganese (Mn), copper (Cu), and zinc (Zn) in soil, and their uptake by plants...... in the organism and the chemical concentration in the growth substrate) and foliar Fe:Mn ratio in each plant was calculated. Our results showed that soil available Fe, Mn and Cu concentrations increased under N addition and were negatively correlated with both soil pH and cation exchange capacity. Water addition...... under the two environmental change factors in a semi-arid grassland of Inner Mongolia. We measured concentrations of trace elements in soil and in foliage of five common herbaceous species including 3 forbs and 2 grasses. In addition, bioaccumulation factors (BAF, the ratio of the chemical concentration...

Evolution of trace elements in the planetary boundary layer in southern China: Effects of dust storms and aerosol-cloud interactions

Science.gov (United States)

Li, Tao; Wang, Yan; Zhou, Jie; Wang, Tao; Ding, Aijun; Nie, Wei; Xue, Likun; Wang, Xinfeng; Wang, Wenxing

2017-03-01

Aerosols and cloud water were analyzed at a mountaintop in the planetary boundary layer in southern China during March-May 2009, when two Asian dust storms occurred, to investigate the effects of aerosol-cloud interactions (ACIs) on chemical evolution of atmospheric trace elements. Fe, Al, and Zn predominated in both coarse and fine aerosols, followed by high concentrations of toxic Pb, As, and Cd. Most of these aerosol trace elements, which were affected by dust storms, exhibited various increases in concentrations but consistent decreases in solubility. Zn, Fe, Al, and Pb were the most abundant trace elements in cloud water. The trace element concentrations exhibited logarithmic inverse relationships with the cloud liquid water content and were found highly pH dependent with minimum concentrations at the threshold of pH 5.0. The calculation of Visual MINTEQ model showed that 80.7-96.3% of Fe(II), Zn(II), Pb(II), and Cu(II) existed in divalent free ions, while 71.7% of Fe(III) and 71.5% of Al(III) were complexed by oxalate and fluoride, respectively. ACIs could markedly change the speciation distributions of trace elements in cloud water by pH modification. The in-cloud scavenging of aerosol trace elements likely reached a peak after the first 2-3 h of cloud processing, with scavenging ratios between 0.12 for Cr and 0.57 for Pb. The increases of the trace element solubility (4-33%) were determined in both in-cloud aerosols and postcloud aerosols. These results indicated the significant importance of aerosol-cloud interactions to the evolution of trace elements during the first several cloud condensation/evaporation cycles.

Investigation on microstructure characterization and property of rapidly solidified Mg-Zn-Ca-Ce-La alloys

Energy Technology Data Exchange (ETDEWEB)

Zhou Tao, E-mail: tzhou1118@163.com [College of Material Science and Engineering, Chongqing University of Technology, Chongqing 400054 (China); Chen Zhenhua, E-mail: chenzhenhua45@hotmail.com [College of Material Science and Engineering, Hunan University, Changsha 410082 (China); Yang Mingbo, E-mail: yangmingbo@cqit.edu.cn [College of Material Science and Engineering, Chongqing University of Technology, Chongqing 400054 (China); Hu Jianjun, E-mail: hujj@qq.com [College of Material Science and Engineering, Chongqing University of Technology, Chongqing 400054 (China); Xia Hua, E-mail: xiahua@cqut.edu.cn [College of Material Science and Engineering, Chongqing University of Technology, Chongqing 400054 (China)

2012-01-15

Rapidly solidified (RS) Mg-Zn-Ca-Ce-La (wt.%) alloys have been produced via atomizing the alloy melt and subsequent splat-quenching on the water-cooled copper twin-rollers in the form of flakes. Microstructure characterization, phase compositions and thermal stability of the alloys have been systematically investigated. The results showed that with addition of RE (Ce and La) to the Mg-6Zn-5Ca alloy, the stable intermetallic compounds i.e. the Mg{sub x}Zn{sub y}RE{sub z} phase with a few Ca (about 3 at.%), shortened as the T Prime phase, were formed at the expense of the binary Mg-Zn and Ca{sub 2}Mg{sub 6}Zn{sub 3} phases, which was possibly beneficial to the enhanced thermal stability of the alloy. In the Mg-6Zn-5Ca-3Ce-0.5La alloy, the composition of the T Prime phase in the grain interior was different from that at the grain boundaries, in which the segregation of the La elements was found, and the atomic percentage ratio of Zn to Ce in the T Prime phase within the grains was close to 2. Moreover, the stable Mg{sub 2}Ca phases were detected around the T Prime phases at the grain boundaries in the alloy. - Research Highlights: Black-Right-Pointing-Pointer The phase constitution of RS Mg-6Zn-5Ca alloy can be improved by RE additions. Black-Right-Pointing-Pointer In the Mg-Zn-Ca-Ce-La alloys, the Mg{sub x}Zn{sub y}RE{sub z} phase with a few Ca (T Prime phase) is formed. Black-Right-Pointing-Pointer The formation of the T Prime phase leads to the loss of the Mg-Zn and Ca{sub 2}Mg{sub 6}Zn{sub 3} phases. Black-Right-Pointing-Pointer The composition of the T Prime phase differs from the grain interior to the grain boundary.

Microstructure, mechanical properties, biocorrosion behavior, and cytotoxicity of as-extruded Mg-Nd-Zn-Zr alloy with different extrusion ratios.

Science.gov (United States)

Zhang, Xiaobo; Yuan, Guangyin; Niu, Jialin; Fu, Penghuai; Ding, Wenjiang

2012-05-01

Recently, commercial magnesium (Mg) alloys containing Al (such as AZ31 and AZ91) or Y (such as WE43) have been studied extensively for biomedical applications. However, these Mg alloys were developed as structural materials, not as biomaterials. In this study, a patented Mg-Nd-Zn-Zr (denoted as JDBM) alloy was investigated as a biomedical material. The microstructure, mechanical properties, biocorrosion behavior, and cytotoxicity of the alloy extruded at 320 °C with extrusion ratios of 8 and 25 were studied. The results show that the lower extrusion ratio results in finer grains and higher strength, but lower elongation, while the higher extrusion ratio results in coarser grains and lower strength, but higher elongation. The biocorrosion behavior of the alloy was investigated by hydrogen evolution and mass loss tests in simulated body fluid (SBF). The results show that the alloy extruded with lower extrusion ratio exhibits better corrosion resistance. The corrosion mode of the alloy is uniform corrosion, which is favorable for biomedical applications. Aging treatment on the as-extruded alloy improves the strength and decreases the elongation at room temperature, and has a small positive influence on the corrosion resistance in SBF. The cytotoxicity test indicates that the as-extruded JDBM alloy meets the requirement of cell toxicity. Copyright © 2012 Elsevier Ltd. All rights reserved.

Characterization of 68Zn uptake, translocation, and accumulation into developing grains and young leaves of high Zn-density rice genotype*

Science.gov (United States)

Wu, Chun-yong; Feng, Ying; Shohag, Md. Jahidul Islam; Lu, Ling-li; Wei, Yan-yan; Gao, Chong; Yang, Xiao-e

2011-01-01

Zinc (Zn) is an essential micronutrient for humans, but Zn deficiency has become serious as equally as iron (Fe) and vitamin A deficiencies nowadays. Selection and breeding of high Zn-density crops is a suitable, cost-effective, and sustainable way to improve human health. However, the mechanism of high Zn density in rice grain is not fully understood, especially how Zn transports from soil to grains. Hydroponics experiments were carried out to compare Zn uptake and distribution in two different Zn-density rice genotypes using stable isotope technique. At seedling stage, IR68144 showed higher 68Zn uptake and transport rate to the shoot for the short-term, but no significant difference was observed in both genotypes for the long-term. Zn in xylem sap of IR68144 was consistently higher, and IR68144 exhibited higher Zn absorption ratio than IR64 at sufficient (2.0 µmol/L) or surplus (8.0 µmol/L) Zn supply level. IR64 and IR68144 showed similar patterns of 68Zn accumulation in new leaves at seedling stage and in developing grains at ripening stage, whereas 68Zn in new leaves and grains of IR68144 was consistently higher. These results suggested that a rapid root-to-shoot translocation and enhanced xylem loading capacity may be the crucial processes for high Zn density in rice grains. PMID:21528496

Electronic and elemental properties of the Cu{sub 2}ZnSn(S,Se){sub 4} surface and grain boundaries

Energy Technology Data Exchange (ETDEWEB)

Haight, Richard; Shao, Xiaoyan; Wang, Wei; Mitzi, David B. [IBM T. J. Watson Research Center, P.O. Box 218, Yorktown Hts., New York 10598 (United States)

2014-01-20

X-ray and femtosecond UV photoelectron spectroscopy, secondary ion mass spectrometry and photoluminescence imaging were used to investigate the electronic and elemental properties of the CZTS,Se surface and its oxides. Oxide removal reveals a very Cu poor and Zn rich surface relative to bulk composition. O and Na are observed at the surface and throughout the bulk. Upward bending of the valence bands indicates the presence of negative charge in the surface region and the Fermi level is found near the band gap center. The presence of point defects and the impact of these findings on grain boundary properties will be described.

Nano-ZnO Doping Induced Changes in Structure, Mechanical and Optical Properties of PVA Films

International Nuclear Information System (INIS)

Abdel-Galil, A.; BalboulM, R.; Ali, H.E.

2015-01-01

Zinc oxide ( ZnO ) nanoparticles ( NPs) were synthesized using t he co-precipitation method. Transmission electron microscope (TEM) was used to confirm the nanoparticle size of the ZnO powder sample. ZnO NPs (with different ratios) were dispersed into polyvinyl alcohol (PVA) matrix to get ZnO/PVA nano composites using the blending method. The structure of Pva polymer and ZnO/PVA nano composites was identified by X - ray diffraction (XRD). Thermogravimetric analysis (TGA) of PVA and ZnO/PVA nano composites has been carried out before and after γ- irradiation with different doses . The TGA , DTG thermo grams and the degradation activation energy have been studied. The results indicated the enhancement in thermal stability of PVA polymer as an effect of ZnO NPs. Irradiation doses lead to a change in the degradation activation energy as a result of the degradation and cross- linking processes of the PVA polymer. Moreover, the mechanical performance of PVA polymer has been improved by adding ZnO NPs and by γ- irradiation. The optical band gap of the PVA film was investigated with different ratios of ZnO NPs. The band gap de creased with increasing the ZnO NPs ratio. The effect of γ-irradiation, with different doses on the optical band gap of ZnO/PVA nano composites also has been studied

Synthesis of ZnO nanorods and observation of resistive switching memory in ZnO based polymer nanocomposites

Science.gov (United States)

Nair, Manjula G.; Malakar, Meenakshi; Mohapatra, Saumya R.; Chowdhury, Avijit

2018-05-01

This research reports the observation of bipolar resistive switching memory in ZnO nanorod based polymer nanocomposites. We synthesized ZnO nanorods by wet-chemical method and characterized them using XRD, UV-VIS spectroscopy and SEM. The synthesized materials have hexagonal ZnO phase with grain size of 24 nm and having strong orientation along (101) direction as observed from XRD. The SEM micrograph confirms the formation of ZnO nanorods with diameter in the range of 10 to 20 nm and length of the order of 1 µm. From optical absorption spectra the band gap is estimated to be 2.42 eV. ZnO nanorods were dispersed in PVDF-HFP polymer matrix to prepare the nanocomposite. This nanocomposite was used as active layer in the devices having sandwich structure of ITO/PVDF-HFP+ZnO nanorods/Al. Bipolar non-volatile memory was observed with ON-OFF resistance ratio of the order of 103 and with a wide voltage window of 2.3V. The switching mechanism could be due to the trapping and de-trapping of electrons by the ZnO nanorods in the nanocomposite during ON and OFF states respectively.

Effects of Post- Heat Treatment of Nanocrystalline ZnO Thin Films deposited on Zn-Deposited FTO Substrates

Energy Technology Data Exchange (ETDEWEB)

Kim, Ikhyun; Kim, Younggyu; Nam, Giwoong; Leem, Jae-Young [Inje University, Gimhae (Korea, Republic of)

2015-10-15

The effects of heat-treatment temperature on the structural and optical properties of ZnO thin films were investigated with field-effect scanning electron microscopy (SEM), X-ray diffraction analysis, and photoluminescence (PL) measurements. The ZnO thin films were grown on Zn-deposited fluorine-doped tin oxide substrates by sol-gel spin coating. The SEM images of the samples showed that their surfaces had a mountain-chain-like structure. The film annealed at 400 ℃ had the highest degree of alignment along the c-axis, and its residual stress was close to zero. The PL spectra of the ZnO thin films consisted of sharp near-band-edge emissions (NBE) and broad deep-level emissions (DLE) in the visible range. The DLE peaks exhibited a green-to-red shift with an increase in the temperature. The highest INBE/IDLE ratio was observed in the film annealed at 400 ℃. Thus, the optimal temperature for growing high-quality ZnO thin films on Zn-deposited FTO substrates is 400 ℃.

Ligand-assisted fabrication, structure, and luminescence properties of Fe:ZnSe quantum dots

International Nuclear Information System (INIS)

Xie, Ruishi; Zhang, Xingquan; Liu, Haifeng

2014-01-01

Highlights: • A green route is developed for synthesis of water-soluble and fluorescent Fe:ZnSe quantum dots. • Tunable luminescence intensity can be realized with different ligand-to-Zn molar ratios. • The obtained quantum dots are in the so-called “quantum confinement regime”. -- Abstract: Here, we report a synthetic route for highly emissive Fe:ZnSe quantum dots in aqueous media using the mercaptoacetic acid ligand as stabilizing agent. The structural, morphological, componential, and optical properties of the resulting quantum dots were explored by the X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray spectroscopy, inductively coupled plasma mass spectrometry, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, photoluminescence and UV–visible absorption spectroscopies. The average crystallite size was calculated to be about ca., 4.0 nm using the Scherrer equation, which correlates well with the value obtained from the transmission electron microscopy analysis. The obtained water-soluble Fe:ZnSe quantum dots in the so-called “quantum confinement regime” are spherical shaped, possess the cubic sphalerite crystal structure, and exhibit tunable luminescence properties. The presence of mercaptoacetic acid on the surface of Fe:ZnSe quantum dots was confirmed by the Fourier transform infrared spectroscopy measurements. As the ligand/Zn molar ratio increases from 1.3 to 2.8, there is little shift in the absorption peak of the Fe:ZnSe sample, indicating that the particle size of the obtained quantum dots is not changed during the synthetic process. The photoluminescence quantum yield of the as-prepared water-soluble Fe:ZnSe quantum dots can be up to 39%. The molar ratio of ligand-to-Zn plays a crucial role in determining the final luminescence properties of the resulting quantum dots, and the maximum PL intensity appears as the ligand-to-Zn molar ratio is 2.2. In addition, the underlying mechanism for

Ligand-assisted fabrication, structure, and luminescence properties of Fe:ZnSe quantum dots

Energy Technology Data Exchange (ETDEWEB)

Xie, Ruishi, E-mail: rxie@foxmail.com; Zhang, Xingquan; Liu, Haifeng

2014-03-15

Highlights: • A green route is developed for synthesis of water-soluble and fluorescent Fe:ZnSe quantum dots. • Tunable luminescence intensity can be realized with different ligand-to-Zn molar ratios. • The obtained quantum dots are in the so-called “quantum confinement regime”. -- Abstract: Here, we report a synthetic route for highly emissive Fe:ZnSe quantum dots in aqueous media using the mercaptoacetic acid ligand as stabilizing agent. The structural, morphological, componential, and optical properties of the resulting quantum dots were explored by the X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray spectroscopy, inductively coupled plasma mass spectrometry, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, photoluminescence and UV–visible absorption spectroscopies. The average crystallite size was calculated to be about ca., 4.0 nm using the Scherrer equation, which correlates well with the value obtained from the transmission electron microscopy analysis. The obtained water-soluble Fe:ZnSe quantum dots in the so-called “quantum confinement regime” are spherical shaped, possess the cubic sphalerite crystal structure, and exhibit tunable luminescence properties. The presence of mercaptoacetic acid on the surface of Fe:ZnSe quantum dots was confirmed by the Fourier transform infrared spectroscopy measurements. As the ligand/Zn molar ratio increases from 1.3 to 2.8, there is little shift in the absorption peak of the Fe:ZnSe sample, indicating that the particle size of the obtained quantum dots is not changed during the synthetic process. The photoluminescence quantum yield of the as-prepared water-soluble Fe:ZnSe quantum dots can be up to 39%. The molar ratio of ligand-to-Zn plays a crucial role in determining the final luminescence properties of the resulting quantum dots, and the maximum PL intensity appears as the ligand-to-Zn molar ratio is 2.2. In addition, the underlying mechanism for

Measurement of K-shell jump ratios and jump factors for some elements in 76≤Z≤92 using EDXRF spectrometer

International Nuclear Information System (INIS)

Kaya, N.; Apaydin, G.; Tirasoglu, E.

2011-01-01

This article presents experimental values of the K-shell jump factor and jump ratio (ratio of the K-shell photoionization cross section to the photoionization cross section of the rest of the atom at the K edge) for some elements in 76≤Z≤92 using an energy dispersive X-ray fluorescence (EDXRF) spectrometer and compares those values with the theoretical ones giving reasonable agreement. The experimental values have been determined using the fluorescence parameters: K α production cross sections, K β /K α X-rays intensity ratios, total atomic attenuation cross sections, etc. To the best of our knowledge, K-shell jump ratios and jump factors have been measured without having any data on K edge for the first time in these elements. The results have been plotted versus atomic number.

Calibration and correction of LA-ICP-MS and LA-MC-ICP-MS analyses for element contents and isotopic ratios

Directory of Open Access Journals (Sweden)

Jie Lin

2016-06-01

Full Text Available LA-ICP-MS and LA-MC-ICP-MS have been the techniques of choice for achieving accurate and precise element content and isotopic ratio, the state-of-the-art technique combines the advantages of low detection limits with high spatial resolution, however, the analysis accuracy and precision are restricted by many factors, such as sensitivity drift, elemental/isotopic fractionation, matrix effects, interferences and the lack of sufficiently matrix-matched reference materials. Thus, rigorous and suitable calibration and correction methods are needed to obtain quantitative data. This review systematically summarized and evaluated the interference correction, quantitative calculation and sensitivity correction strategies in order to provide the analysts with suitable calibration and correction strategies according to the sample types and the analyzed elements. The functions and features of data reduction software ICPMSDataCal were also outlined, which can provide real-time and on-line data reduction of element content and isotopic ratios analyzed by LA-ICP-MS and LA-MC-ICP-MS.

Comparison of the concentrations of metal elements and isotopes of lead found in rice and rice bran.

Science.gov (United States)

Dai, Shouhui; Yang, Hui; Yang, Lan; Wang, Fuhua; Du, Ruiying; Wen, Dian

2014-08-01

Very few studies have investigated the difference in the distribution of metal elements between rice and rice bran samples. In this study, the concentrations of 27 metal elements (Li, Be, Na, Mg, Al, K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Ag, Cd, Cs, Ba, Tl, Pb, and U) in 56 polished rice and their corresponding bran samples were determined. A significant difference in concentrations of all elements except Ag and Cd was found between rice and bran (P rice ratios of 1.21 to 36.3. High concentrations of metal elements, especially that of the heavy metal Cr, in bran samples present a potential safety issue for bran products, such as food and feed containing bran. Pb isotope ((204)Pb, (206)Pb, (207)Pb, and (208)Pb) ratios also were determined. The (206)Pb/(207)Pb and (208)Pb/(207)Pb ratios in bran were generally higher than those in rice (P rice and bran samples were distinctly different from each other, indicating that Pb isotope composition is an effective for discriminating between bran and rice samples.

Short-term influence of Cu, Zn, Ni and Cd excess on metabolism, ultrastructure and distribution of elements in lichen Xanthoria parietina (L.) Th. Fr.

Science.gov (United States)

Piovár, J; Weidinger, M; Bačkor, M; Bačkorová, M; Lichtscheidl, I

2017-11-01

Lichens are symbiotic organisms that are very sensitive to heavy metal pollution. However, there is little evidence of how heavy metal pollution affects the physiological status, ultrastructural changes and distribution of elements in the layers of lichen thalli. For this purpose we simulated metal pollution to lichens and studied its impact on Xanthoria parietina. Thalli were treated with the heavy metals Cu, Zn, Ni, Cd in the form of sulfates at concentrations of 100µM and 500µM during 24, 48 and 72h. Untreated lichens served as controls. We assessed the status of physiological parameters (fluorescence and integrity of chlorophyll a, content of soluble proteins and ergosterol), ultrastructural changes, especially to the photobiont, and the distribution of elements in the layers of thalli in relation to treatment with heavy metals. We found positive correlations between the content of all tested heavy metals and the physiological response. We assessed the toxicity of the selected metals as follows: Cd >= Cu >= Ni > Zn, based on the effects on the photobiont layer in the lichen thallus and physiological measurements. Copyright © 2017 Elsevier Inc. All rights reserved.

Measurement of Ca, Zn and Sr in enamel of human teeth by XRF

Energy Technology Data Exchange (ETDEWEB)

Wielopolski, L.; Featherstone, J.D.B.; Cohn, S.H.

1984-01-01

Energy dispersive x-ray fluorescence (EDXRF) has been employed to measure Ca, Zn, and Sr in enamel of human teeth. The calibration of the EDXRF system was performed by comparing Sr/Ca ratios with values obtained by atomic absorption analysis of acid etched biopsies of the enamel surface. Two calibration lines were obtained, one line for untreated teeth and the second line for teeth immersed (treated) in solutions containing Sr. A simple analytical model demonstrated that the two calibration lines were the result of the difference in the depth of the enamel sampled by EDXRF and by the acid-etched biopsy. The multi-elemental, non-destructive and quantitative aspects of EDXRF permit the sequential monitoring of the effects of Sr and Zn ions on the mineralization and demineralization processes in human enamel. The portability of the system and adaptability to non-invasive measurements makes it suitable for field studies. 26 references, 4 figures.

Measurement of Ca, Zn and Sr in enamel of human teeth by XRF

International Nuclear Information System (INIS)

Wielopolski, L.; Featherstone, J.D.B.; Cohn, S.H.

1984-01-01

Energy dispersive x-ray fluorescence (EDXRF) has been employed to measure Ca, Zn, and Sr in enamel of human teeth. The calibration of the EDXRF system was performed by comparing Sr/Ca ratios with values obtained by atomic absorption analysis of acid etched biopsies of the enamel surface. Two calibration lines were obtained, one line for untreated teeth and the second line for teeth immersed (treated) in solutions containing Sr. A simple analytical model demonstrated that the two calibration lines were the result of the difference in the depth of the enamel sampled by EDXRF and by the acid-etched biopsy. The multi-elemental, non-destructive and quantitative aspects of EDXRF permit the sequential monitoring of the effects of Sr and Zn ions on the mineralization and demineralization processes in human enamel. The portability of the system and adaptability to non-invasive measurements makes it suitable for field studies. 26 references, 4 figures

Measurement of Ca, Zn, and Sr in enamel of human teeth by XRF

International Nuclear Information System (INIS)

Wielopolski, L.; Featherstone, J.D.b.; Cohn, S.H.

1984-01-01

Energy dispersive x-ray fluorescence (EDXRF) has been employed to measure Ca, Zn, and Sr in enamel of human teeth. The calibration of the EDXRF system was performed by comparing Sr/Ca ratios with values obtained by atomic absorption analysis of acid etched biopsies of the enamel surface. Two calibration lines were obtained, one line for untreated teeth and the second line for teeth immersed (treated) in solutions containing Sr. A simple analytical model demonstrated that the two calibration lines were the result of the difference in the depth of the enamel sampled by EDXRF and by the acid-etched biopsy. The multi-elemental, non-destructive and quantitative aspects of EDXRF permit the sequential monitoring of the effects of Sr and Zn ions on the mineralization and demineralization processes in human enamel. The portability of the system and adaptability to non-invasive measurements makes it suitable for field studies. 26 references, 4 figures

Morphological and Relative Humidity Sensing Properties of Pure ZnO Nanomaterial

Directory of Open Access Journals (Sweden)

N. K. Pandey

2010-11-01

Full Text Available In this paper we report the resistive type humidity sensing properties of pure ZnO nanomaterial prepared by solid-state reaction method. Pellets of pure ZnO nanocrystalline powder have been made with 10 weight % of glass powder at pressure of 260 MPa by hydraulic press machine for 3 hours. These pellets have been sintered at temperatures 200 °C - 500 °C in an electric muffle furnace for 3 hours at heating rate of 5°C/min. After sintering, these pellets have been exposed to humidity in a specially designed humidity chamber at room temperature. It has been observed that as relative humidity increases, resistance of the pellets decreases for entire range of humidity i.e. 10 % to 90 %. The sensing element of ZnO shows best results with sensitivity of 11.13 MΩ/%RH for the annealing temperature of 400 °C. This sensing element manifests lower hysteresis, less effect of aging and high reproducibility for annealing temperature 400 °C. SEM micrographs show that the sensing elements manifest porous structure with a network of pores that are expected to provide sites for humidity adsorption. The average grain size calculated from SEM micrograph is 236 nm. XRD pattern shows peaks of hexagonal zincite. As calculated from Scherer’s formula, the average crystalline size for this sensing element is 59.4 nm. For this sensing element, the values of activation energy from the Arrhenius plot is 0.041 eV for temperature range 200 °C - 400 °C and 0.393 eV for temperature range 400 °C - 500 °C. The adsorption of water molecules on the surface takes place via a dissociative chemisorption process leading to release of electrons. ZnO has electron vacancy. Hence, because of this reaction, the electrons are accumulated at the ZnO surface and consequently, the resistance of the sensing element decreases with increase in relative humidity.

Measurement of L3 subshell absorption jump ratios and jump factors for high Z elements using EDXRF technique

International Nuclear Information System (INIS)

Kaçal, M.R.

2014-01-01

Energy dispersive X-ray fluorescence technique (EDXRF) has been employed for measuring L 3 -subshell absorption jump ratios, r L 3 and jump factors, J L 3 for high Z elements. Jump factors and jump ratios for these elements have been determined by measuring L 3 subshell fluorescence parameters such as L 3 subshell X-ray production cross section σ L 3 , L 3 subshell fluorescence yield, ω L 3 , total L 3 subshell and higher subshells photoionization cross section σ L T . Measurements were performed using a Cd-109 radioactive point source and an Si(Li) detector in direct excitation experimental geometry. Measured values for jump factors and jump ratios have been compared with theoretically calculated and other experimental values. - Highlights: • This paper regards L 3 subshell absorption jump ratios and jump factors using the EDXRF method. • These parameters were measured using a new method. • This method is more useful than other methods which require much effort. • Results are in good agreement with theoretical and experimental values

Solvothermal synthesis of 3D photonic crystals based on ZnS/opal system

Energy Technology Data Exchange (ETDEWEB)

Chang Xin [Nanomaterials Research Institute, College of Material Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Cao Jieming [Nanomaterials Research Institute, College of Material Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China)]. E-mail: jmcao@nuaa.edu.cn; Ji Hongmei [Nanomaterials Research Institute, College of Material Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Fang Baoqing [Nanomaterials Research Institute, College of Material Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Feng Jie [Nanomaterials Research Institute, College of Material Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Pan Lijia [Nanomaterials Research Institute, College of Material Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Zhang Fang [Nanomaterials Research Institute, College of Material Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Wang, Haiyan [Nanomaterials Research Institute, College of Material Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China)

2005-01-15

We made photonic crystals composed of artificial opals infiltrated with ZnS semiconductor nanocrystals by using self-assembly and solvothermal methods. SEM images show that the silica spheres exhibit a well-ordered arrangement and the ZnS nanocrystals infiltrate within the opal templates by heterogeneous nucleation and growth processing, and the as-synthesized ZnS nanocrystals reveal a cubic phase from X-ray diffraction pattern. Furthermore, the optical properties of the infiltrated opals with different ZnS filling ratio are also studied by transmission spectroscopy, respectively. It is proposed that the position of the stop band can be easily designed by controlling the infiltration ratio of ZnS. These results demonstrate an easy-to-handle and efficient route to obtain high performance photonic crystal structures.

Solvothermal synthesis of 3D photonic crystals based on ZnS/opal system

International Nuclear Information System (INIS)

Chang Xin; Cao Jieming; Ji Hongmei; Fang Baoqing; Feng Jie; Pan Lijia; Zhang Fang; Wang, Haiyan

2005-01-01

We made photonic crystals composed of artificial opals infiltrated with ZnS semiconductor nanocrystals by using self-assembly and solvothermal methods. SEM images show that the silica spheres exhibit a well-ordered arrangement and the ZnS nanocrystals infiltrate within the opal templates by heterogeneous nucleation and growth processing, and the as-synthesized ZnS nanocrystals reveal a cubic phase from X-ray diffraction pattern. Furthermore, the optical properties of the infiltrated opals with different ZnS filling ratio are also studied by transmission spectroscopy, respectively. It is proposed that the position of the stop band can be easily designed by controlling the infiltration ratio of ZnS. These results demonstrate an easy-to-handle and efficient route to obtain high performance photonic crystal structures

Silicon (Si) alleviates cotton (Gossypium hirsutum L.) from zinc (Zn) toxicity stress by limiting Zn uptake and oxidative damage.

Science.gov (United States)

Anwaar, Shad Ali; Ali, Shafaqat; Ali, Skhawat; Ishaque, Wajid; Farid, Mujahid; Farooq, Muhammad Ahsan; Najeeb, Ullah; Abbas, Farhat; Sharif, Muhammad

2015-03-01

Silicon (Si) is as an important fertilizer element, which has been found effective in enhancing plant tolerance to variety of biotic and a-biotic stresses. This study investigates the Si potential to alleviate zinc (Zn) toxicity stress in cotton (Gossypium hirsutum L.). Cotton plants were grown in hydroponics and exposed to different Zn concentration, 0, 25, and 50 μM, alone and/or in combination with 1 mM Si. Incremental Zn concentration in growth media instigated the cellular oxidative damage that was evident from elevated levels of hydrogen peroxide (H2O2), electrolyte leakage, and malondialdehyde (MDA) and consequently inhibited cotton growth, biomass, chlorophyll pigments, and photosynthetic process. Application of Si significantly suppressed Zn accumulation in various plant parts, i.e., roots, stems, and leaves and thus promoted biomass, photosynthetic, growth parameters, and antioxidant enzymes activity of Zn-stressed as well unstressed plants. In addition, Si reduced the MDA and H2O2 production and electrolyte leakage suggesting its role in protecting cotton plants from Zn toxicity-induced oxidative damage. Thus, the study indicated that exogenous Si application could improve growth and development of cotton crop experiencing Zn toxicity stress by limiting Zn bioavailability and oxidative damage.

The transfer and fate of Pb from sewage sludge amended soil in a multi-trophic food chain: a comparison with the labile elements Cd and Zn.

Science.gov (United States)

Dar, Mudasir Irfan; Khan, Fareed Ahmad; Green, Iain D; Naikoo, Mohd Irfan

2015-10-01

The contamination of agroecosystems due to the presence of trace elements in commonly used agricultural materials is a serious issue. The most contaminated material is usually sewage sludge, and the sustainable use of this material within agriculture is a major concern. This study addresses a key issue in this respect, the fate of trace metals applied to soil in food chains. The work particularly addresses the transfer of Pb, which is an understudied element in this respect, and compares the transfer of Pb with two of the most labile metals, Cd and Zn. The transfer of these elements was determined from sludge-amended soils in a food chain consisting of Indian mustard (Brassica juncea), the mustard aphid (Lipaphis erysimi) and a predatory beetle (Coccinella septempunctata). The soil was amended with sludge at rates of 0, 5, 10 and 20 % (w/w). Results showed that Cd was readily transferred through the food chain until the predator trophic level. Zn was the most readily transferred element in the lower trophic levels, but transfer to aphids was effectively restricted by the plant regulating shoot concentration. Pb had the lowest level of transfer from soil to shoot and exhibited particular retention in the roots. Nevertheless, Pb concentrations were significantly increased by sludge amendment in aphids, and Pb was increasingly transferred to ladybirds as levels increased. The potential for Pb to cause secondary toxicity to organisms in higher trophic levels may have therefore been underestimated.

Preparation and electrical properties of ZnO/CdS/Cu (In, Zn) Se2 (ZCIS) heterojunctions

International Nuclear Information System (INIS)

Ivanov, V.A.; Gremenok, V.F.; Zalesski, V.B.; Kovalevski, V.I.; Bente, K.

2010-01-01

Full text : Cu(In,Zn)Se 2 (ZCIS) is one of the most promising materials for commercial photovoltaic applications. This is due to the high absorption coefficient of approximately 105 cm - 1 in a wide spectral region and a band gap that is in principle adjustable between 1.05 eV for CuInSe 2 and 2.60 eV for ZnSe. Therefore they are suggested to be used in thin film solar cells as absorber as well a wide-gap window layers. The Cu/(In+Zn) ratio of the ZCIS layers is the important parameter for the physical properties of the semiconductor material as well for the solar cell applications. The presented results consider the preparation as well as the chemical, structural and physical characterization of the electrical properties of the ZnO/CdS/CuIn0, 94Zn0, 06Se2 thin films hetero junctions. The ZCIS films were prepared by two-step selenization of Cu-In-ZnSe layers under N2 flow by evaporating a solid Se source close to samples. Such technology is especially suited for developments of industrial processing of large area ZCIS films suitable for solar cells. Cu-In-ZnSe layers were deposited onto Mo-coated soda lime glass substrates by thermal evaporation or sputtering. The Zn content in the ZCIS films was controlled by choise of In/ZnSe ratio in the initial alloy. Buffer layers of CdS were deposited onto the ZCIS films in the chemical bath. The ZnO films were deposited onto CdS by thermal evaporation. The ZnO and CdS films were detected to be polycrystalline with thicknesses of 0.4im and 0.06im respectively and revealed n-type conductivity. The ''Leit-C'' conductive glue was used as electrical contacts. The effective area of each cell was about 0.8 cm2. Under non-illuminated conditions, I - V characteristics of the heterojunctions were approximately exponential at low voltages according to the standard diode equation I=Io[exp(eV/nkT)-1], with a slight deviation from this behaviour at high voltages due to a series of resistance effects. The capacitance of the heterojunctions

XRF Studies of Trace Elements and Essential hypertension

International Nuclear Information System (INIS)

Chaudhri, M.A.; Paul, U.; Chaudhri, M.N.

2011-01-01

The elemental concentrations in the blood of fully mature spontaneously hypertensive rats [SHR] were compared with that of normotensive Wistar Kyoto rats [WKy] with an energy- dispersive XRF-system using a Rhodium X-ray tube. A number of elements, Na, Mg, P, Cl, S, K, Ca, Fe, Cu, Zn, Rb and Br, ranging in concentrations from a few ppm to around 1 % were measured in all the blood samples. It has been observed that the concentrations of elements Na, Cu, Zn and Br in whole blood of SHR are about 5%, 17%, 7% and 21% higher respectively than in the WKy- group

Synthesis of High Crystalline Al-Doped ZnO Nanopowders from Al2O3 and ZnO by Radio-Frequency Thermal Plasma

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Min-Kyeong Song

2015-01-01

Full Text Available High crystalline Al-doped ZnO (AZO nanopowders were prepared by in-flight treatment of ZnO and Al2O3 in Radio-Frequency (RF thermal plasma. Micron-sized (~1 μm ZnO and Al2O3 powders were mixed at Al/Zn ratios of 3.3 and 6.7 at.% and then injected into the RF thermal plasma torch along the centerline at a feeding rate of 6.6 g/min. The RF thermal plasma torch system was operated at the plate power level of ~140 kVA to evaporate the mixture oxides and the resultant vapor species were condensed into solid particles by the high flow rate of quenching gas (~7000 slpm. The FE-SEM images of the as-treated powders showed that the multipod shaped and the whisker type nanoparticles were mainly synthesized. In addition, these nanocrystalline structures were confirmed as the single phase AZO nanopowders with the hexagonal wurtzite ZnO structure by the XRD patterns and FE-TEM results with the SAED image. However, the composition changes of 0.3 and 1.0 at.% were checked for the as-synthesized AZO nanopowders at Al/Zn ratios of 3.3 and 6.7 at.%, respectively, by the XRF data, which can require the adjustment of Al/Zn in the mixture precursors for the applications of high Al doping concentrations.

Trace elements in Taiwanese diet in different seasons

International Nuclear Information System (INIS)

Sheng-Ming Liu; Chien Chung

1992-01-01

The trace element contents of Taiwanese diet were determined using conventional neutron activation analysis. Sample were prepared with duplicate portion technique by collecting food items ate and drank during a 3 day period in winter. Samples were homogenized, freeze-dried, and elemental concentration of trace elements were determined by instrumental neutron activation analysis. The interference from fast neutron induced reactions were corrected. Concentrations and daily dietary intake of the elements were compared with those collected in the summer, resulting less daily intake of K, Ca, Mn, Fe and Zn among Taiwanese than the values recommended by WHO and RDA. Alarming low intake of Fe for females and Zn among Taiwanese were indicated. (author) 6 refs.; 2 figs.; 5 tabs

Dynamics of ZnO laser produced plasma in high pressure argon

International Nuclear Information System (INIS)

Kaydashev, V.E.; Lunney, J.G.

2011-01-01

Pulsed laser deposition of ZnO in high pressure gas offers a route for the catalyst-free preparation of ZnO nanorods less than 10 nm in diameter. This paper describes the results of some experiments to investigate the laser plume dynamics in the high gas pressure (5 x 10 3 -10 4 Pa) regime used for PLD of ZnO nanorods. In this regime the ablation plume is strongly coupled to the gas and the plume expansion is brought to a halt within about 1 cm from the target. A 248 nm excimer laser was used to ablate a ceramic ZnO target in various pressures of argon. Time- and space-resolved UV/vis emission spectroscopy and Langmuir probe measurements were used to diagnose the plasma and follow the plume dynamics. By measuring the spatial profiles of Zn I and Zn II spectral lines it was possible to follow the propagation of the external and internal shock waves associated with the interaction of the ablation plume with the gas. The Langmuir probe measurements showed that the electron density was 10 9 -10 10 cm -3 and the electron temperature was several eV. At these conditions the ionization equilibrium is described by the collisional-radiative model. The plume dynamics was also studied for ZnO targets doped with elements which are lighter (Mg), comparable to (Ga), and heavier (Er) than Zn, to see if there is any elemental segregation in the plume.

Effect of various amounts of graphene oxide on the degradation characteristics of the ZnSe/graphene nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Hsieh, S.H. [Department of Materials Science and Engineering, National Formosa University, 64, Wunhua Road, Huwei, Yunlin 632, Taiwan (China); Chen, W.J., E-mail: chenwjau@yuntech.edu.tw [Graduate School of Materials Science, National Yunlin University of Science and Technology, 123 University Road, Section 3, Douliou, Yunlin 64002, Taiwan (China); Yeh, T.H. [Graduate School of Materials Science, National Yunlin University of Science and Technology, 123 University Road, Section 3, Douliou, Yunlin 64002, Taiwan (China)

2015-12-15

Graphical abstract: When the ratio of the addition of GO to the amount of ZnSe–N{sub 2}H{sub 4} increases from 0.25 to 1, the degradation effect of GN–5 ml ZnSe on MB increases with increasing GO; the degradation efficiency of GN–ZnSe for MB increased from 35.4% to 99.6% after 6 h of visible light irradiation, which was the optimum degradation efficiency obtained in the present study. When the ratio of the addition of GO to the amount of ZnSe–N{sub 2}H{sub 4} increased from 1 to 2, the degradation efficiency of GN–5 ml ZnSe for MB decreased with the increasing addition of GO; the degradation efficiency of GN–5 ml ZnSe (2) only slightly decreased to 95.3% after 6 h of visible light irradiation. - Highlights: • The ZnSe/graphene nanocomposite was prepared using hydrothermal methods. • The ZnSe–N{sub 2}H{sub 4} reacted with different amount of GO and formed a ZnSe/graphene. • The degradation efficiency of the ZnSe/graphene depends on the amount of GO. • The photocatalytic activity was measured by the degradation of methylene blue. - Abstract: In this work, the graphene oxide (GO) sheets were synthesized by modified Hummers and Offeman's method. The GO was mixed with ZnSe that was prepared using various amounts of N{sub 2}H{sub 4} at a ratio of (0.25–2):1 to form precursors. The ZnSe/graphene nanocomposites were synthesized under hydrothermal conditions (180 °C; 12 h) from the previous precursor. Obtained ZnSe/graphene photocatalysts were characterized by X-ray diffraction analysis (XRD), Fourier transform infrared (FTIR) spectroscopy, UV–vis diffuse reflection spectroscopy, transmission electron microscope, scanning electron microscope, Raman spectra and X-ray photoelectron spectroscopy (XPS). Photocatalytic activity under visible light is evaluated in methylene blue (MB) dye degradation reaction in aqueous phase. The results show that the formation of ZnSe/graphene nanocomposite is depend on ratio of the addition of GO to the amount of

Atmospheric trace elements and Pb isotopes at an offshore site, Ieodo Ocean Research Station, in the East China Sea from June to October 2015

Science.gov (United States)

Lee, S.; Han, C.; Shin, D.; Hur, S. D.; Jun, S. J.; Kim, Y. T.; Hong, S.

2016-12-01

East Asia, especially China, has become a major anthropogenic source region of trace elements due to the rapid industrialization and urbanization in the past decades. Numerous studies reported that anthropogenic pollutants from East Asia are transported by westerly winds during winter to spring across the Pacific to North America and beyond. Here we report elemental concentrations and Pb isotope ratios in airborne particles from Ieodo Ocean Research Station (IORS) located in the middle of the East China Sea (32.07o N, 125.10o E). A total of 30 aerosol samples (PM2.5-10) were collected between 18 June and 30 October 2015 and analyzed for trace elements (Zn, As, Mo, Cd, Sb, Ba, Tl, and Pb) and Pb isotopes using ICP-SFMS and TIMS, respectively. The mean concentrations of trace elements ranged from 0.06 ng m-3 for Tl to 10.1 ng m-3 for Zn. These values are much lower (up to several orders) than those at unban sites in East Asia, confirming a low level of air pollution at IORS due to the remoteness of the site from major sources of anthropogenic pollutants. On the other hand, the mean crustal enrichment factors, calculated using Ba as a conservative crustal element, are much higher than unity (84 for Tl, 100 for Mo, 140 for Pb, 166 for Zn, 262 for As, 526 for Cd, and 570 for Sb, respectively), indicating that these elements are of anthropogenic origin. Combining the Pb isotope ratios and the HYSPLIT model 5-day backward trajectory analysis, we have identified episodic long-range transport of air pollutants from diverse source regions of China, Korea, Japan and Taiwan to the site in summer (June to August). By comparison, an increasing long-range transport of pollution from China was observed in autumn (September and October). Finally, our study shows that IORS is an ideal background site for monitoring levels of concentrations and source origins of atmospheric trace elements in East Asia.

First-principles study of ZnSnAs2-based dilute magnetic semiconductors

Science.gov (United States)

Kizaki, Hidetoshi; Morikawa, Yoshitada

2018-02-01

The electronic structure and magnetic properties of chalcopyrite Zn(Sn,TM)As2 and (Zn,TM)SnAs2 have been investigated by the Korringa-Kohn-Rostoker method combined with the coherent potential approximation within the local spin density approximation, where TM denotes a 3d transition metal element. We find that the half-metallic and high-spin ferromagnetic state can be obtained in Zn(Sn,V)As2, Zn(Sn,Cr)As2, Zn(Sn,Mn)As2, (Zn,V)SnAs2, and (Zn,Cr)SnAs2. The calculated result of Zn(Sn,Mn)As2 is in good agreement with the experimentally observed room-temperature ferromagnetism if we can control selective Mn doping at Sn sites. In addition, (Zn,V)SnAs2 and (Zn,Cr)SnAs2 are predicted to exhibit high-Curie-temperature ferromagnetism.

Synthesis and characterization of polychelates of Cu(II), Ni(II), Co(II), Mn(II), Zn(II), oxovanadium(IV) and dioxouranium(VI) with 2,4-dihydroxybenzaldehyde-urea-formaldehyde polymer

International Nuclear Information System (INIS)

Patel, G.C.; Pancholi, H.B.; Patel, M.M.

1991-01-01

Polychelates of Cu(II), Ni(II), Co(II), Mn(II), Zn(II), oxovandium(IV) and dioxouranium(VI) with 2,4-dihydroxybenzaldehyde (2,4-DB)-urea(U)-formaldehyde(F) polymer (2,4-DBUF) have been prepared. Elemental analyses of the polychelates indicate a metal:ligand ratio of 1:2. The structures of the polychelates have been assigned on the basis of their elemental analyses, IR, reflectance spectra, magnetic moment, thermal data and their electrical conductivity behaviour. (author). 1 tab., 18 refs

Effect of Ce on Casting Structure of Near-rapidly Solidified Al-Zn-Mg-Cu Alloy

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HUANG Gao-ren

2017-11-01

Full Text Available Through using XRD,DSC,SEM,EDS and other modern analysis methods, the effects of rare earth element Ce on microstructure and solidification temperature of Al-Zn-Mg-Cu under different cooling rates were studied, the principle of Ce on grain refining and melt cleaning of alloys was analyzed and discussed. The results show that MgZn2 phase and α-Al matrix are the main precipitations, Al,Cu,Mg and other elements dissolve in MgZn2 phase, a new phase Mg(Zn, Cu, Al2 is formed, solute elements in the grain boundary have higher concentration, eutectic reaction takes place between MgZn2 and α-Al, lamellar eutectic structure is generated. The addition of Ce decreases the dendritic arm spacing,reduces the layer spacing between eutectic phases and refines the eutectic structure and the grain significantly, and inhibits the appearance of the impurity phase Al7Cu2Fe in aluminum alloys. The addition of Ce also reduces the precipitation temperature of α-Al matrix and eutectic phase by 6.4℃ and 5.6℃ respectively.

Numerical study of the influence of ZnTe thickness on CdS/ZnTe solar cell performance

Science.gov (United States)

Skhouni, Othmane; El Manouni, Ahmed; Mari, Bernabe; Ullah, Hanif

2016-05-01

At present most of II-VI semiconductor based solar cells use the CdTe material as an absorber film. The simulation of its performance is realized by means of various numerical modelling programs. We have modelled a solar cell based on zinc telluride (ZnTe) thin film as absorber in substitution to the CdTe material, which contains the cadmium element known by its toxicity. The performance of such photovoltaic device has been numerically simulated and the thickness of the absorber layer has been optimized to give the optimal conversion efficiency. A photovoltaic device consisting of a ZnTe layer as absorber, CdS as the buffer layer and ZnO as a window layer was modelled through Solar Cell Capacitance Simulator Software. Dark and illuminated I-V characteristics and the results for different output parameters of ZnO/CdS/ZnTe solar cell were analyzed. The effect of ZnTe absorber thickness on different main working parameters such as: open-circuit voltage Voc, short-circuit current density Jsc, fill factor FF, photovoltaic conversion efficiency η was intensely studied in order to optimize ZnTe film thickness. This study reveals that increasing the thickness of ZnTe absorber layer results in higher efficiency until a maximum value and then decreases slightly. This maximum was found to be 10% at ZnTe optimum thickness close to 2 µm. Contribution to the topical issue "Materials for Energy Harvesting, Conversion and Storage (ICOME 2015) - Elected submissions", edited by Jean-Michel Nunzi, Rachid Bennacer and Mohammed El Ganaoui

Analysis of trace elements in chicken embryo cells

International Nuclear Information System (INIS)

Qiu Zhijun; Wang Jiqing; Guo Panlin; Li Xiaolin; Zhu Jieqing; Lu Rongrong

2002-01-01

A scanning proton microprobe (SPM) with high resolution and high sensitivity was applied to analyze trace elements in chicken embryo forebrain neutron cell and skeletal muscle myotube cell. The absorption of the two different cells to zinc ions, correlation of elements and trace elemental distributions in the cells were studied. The results indicate that the absorptive capacity of the chicken embryo forebrain neuron cell to zinc ions is larger than that of the chicken embryo skeletal muscle myotube cell, and the concentrations of intracellular trace elements such as Cr, Fe, Ni are explicitly higher. The correlations of elements such as S and Zn or Fe and Zn are positive, but the correlations of P and Ni or Cr and Fe are negative. From the maps of cellular elemental distribution the contents of the different elements are different in the intracellular parts, for example, the contents of the elements phosphorus, sulfur, potassium in the cell membranes are higher than that in the cells

Pristine rocks (8th Foray) - Plagiophile element ratios, crustal genesis, and the bulk composition of the moon

International Nuclear Information System (INIS)

Warren, P.H.; Kallemeyn, G.W.

1984-01-01

Eu/Al, Sr/Al, Eu/Sr, and similar ratios among pristine lunar nonmare lithologies with implications for nonmare petrogenesis and for the bulk composition of the moon are examined. On a plot of Eu/Al versus mg, ferroan anorthosites are separated from all other pristine nonmare rocks by a considerable gap. A nonrandom process must be invoked to account for the gap in the spectrum of ratios. A single magma probably cannot account for even the Mg-rich pristine rocks subset, based on diversity of plagiophile ratios among samples with similar mg ratios. Plagiophile ratios also constrain the bulk composition of the moon. Plagiophile ratios among ferroan anorthosites exactly match those expected under a model in which ferroan anorthosites formed by flotation of plagioclase cumulates over a primordial magmasphere. Ratios among nonvolatile elements confirm that the moon formed out of materials akin to chondritic meteorites

Solvothermal Synthesis of Zn2SnO4 Nanocrystals and Their Photocatalytic Properties

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Guang Sun

2014-01-01

Full Text Available Crystalline Zn2SnO4 nanoparticles were successfully synthesized via a simple solvothermal route by using Zn(CH3COO2·2H2O and SnCl4·5H2O as source materials, NaOH as mineralizing agent, and water and ethanol as mixed solvents. The used amount of NaOH was found to have an important influence on the formation of Zn2SnO4. When the molar ratio of OH− : Zn2+ : Sn4+ was set in the range from 4 : 2 : 1 to 8 : 2 : 1, Zn2SnO4 nanoparticles with different shape and size were obtained. However, when the molar ratio of OH− : Zn2+ : Sn4+ was set as 10 : 2 : 1, a mixture phase of ZnO and ZnSn(OH6 instead of Zn2SnO4 was obtained. Photodegradation measurements indicated that the Zn2SnO4 nanoparticles own better photocatalytic property to depredate methyl orange than the Zn2SnO4 nanopolyhedrons. The superior photocatalytic properties of Zn2SnO4 nanoparticles may be contributed to their small crystal size and high surface area.

Re-partitioning of Cu and Zn isotopes by modified protein expression

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Ragnarsdottir K Vala

2008-10-01

Full Text Available Abstract Cu and Zn have naturally occurring non radioactive isotopes, and their isotopic systematics in a biological context are poorly understood. In this study we used double focussing mass spectroscopy to determine the ratios for these isotopes for the first time in mouse brain. The Cu and Zn isotope ratios for four strains of wild-type mice showed no significant difference (δ65Cu -0.12 to -0.78 permil; δ66Zn -0.23 to -0.48 permil. We also looked at how altering the expression of a single copper binding protein, the prion protein (PrP, alters the isotope ratios. Both knockout and overexpression of PrP had no significant effect on the ratio of Cu isotopes. Mice brains expressing mutant PrP lacking the known metal binding domain have δ65Cu isotope values of on average 0.57 permil higher than wild-type mouse brains. This implies that loss of the copper binding domain of PrP increases the level of 65Cu in the brain. δ66Zn isotope values of the transgenic mouse brains are enriched for 66Zn to the wild-type mouse brains. Here we show for the first time that the expression of a single protein can alter the partitioning of metal isotopes in mouse brains. The results imply that the expression of the prion protein can alter cellular Cu isotope content.

Effect of ZnO and PbO/ZnO on structural and thermal properties of tellurite glasses

International Nuclear Information System (INIS)

Ramamoorthy, Raj Kumar; Bhatnagar, Anil K

2015-01-01

Highlights: • Structural units/linkages variation of TeO 2 -ZnO and TeO 2 -ZnO-PbO glasses was studied. • Structural arrangements of TeO 2 -ZnO glasses are rich in Te-O-Te network. • A mixture of Te-O-Te and Te-O-Pb networks is identified in TeO 2 -ZnO-PbO glasses. • Changes in thermal parameters T g and T o are correlated with the structural variations. • 15PbO and 20PbO samples of TeO 2 -ZnO-PbO glasses show large thermal stability. - Abstract: Two series of glasses, (100 − x)TeO 2 -xZnO (x = 20, 25, 30, 35) and 70TeO 2 -(30 − y)ZnO-yPbO (y = 5, 10, 15, 20), referred as TZ and TZP, respectively, were prepared by a melt quenching technique and characterized by X-ray diffraction (XRD), density, refractive index, Raman scattering and differential scanning calorimetry (DSC) to observe the changes in their properties as a function of ZnO and PbO/ZnO. Variations in individual structural units/linkages in these glasses are derived from the de-convoluted Raman spectra. The glass transition (T g ) and onset of crystallization (T o ) temperatures are determined from DSC isothermal scans. It is observed that the thermal stability (ΔT = T o − T g ) decreases for TZ glasses with increase in x, while it increases for TZP glasses with increase in y. Changes in thermal parameters of these glasses are correlated with the structural variation as a function of ZnO and PbO/ZnO ratio to determine the effect of substitution/addition of metal oxide, ZnO and PbO, to TeO 2 and TeO 2 -ZnO glasses

Uptake of trace elements in adult and suckling rat lenses

International Nuclear Information System (INIS)

Nabekura, Tomohiro; Ito, Yoshimasa; Minami, Takeshi; Hirunuma, Rieko; Enomoto, Shuichi

2001-01-01

The uptake of trace elements in the lens was compared in adult and suckling rat lenses. Multitracers, including 15 trace elements, As, Be, Co, Fe, Mn, Rb, Rh, Ru, Sc, Se, Sr, Y, V, Zn, and Zr, were incubated with the lenses for 4 hr and their concentrations in the lens were measured. A high uptake rate of Zn was observed in the lenses of both adult and suckling rats in comparison with those of the other elements, and the Zn concentration in the lens of suckling rats was higher than that of adult rats. The uptake rate of Sr was higher in adult rats than in suckling rats. On the other contrary, Rb and Se concentrations in the lens were higher in suckling rats than in adult rats. The present study suggests that the different mechanisms depending on development serve to transport trace elements into the lens. (author)

Abridgment of nano and micro length scale mechanical properties of novel Mg–9Li–7Al–1Sn and Mg–9Li–5Al–3Sn–1Zn alloys using object oriented finite element modeling

Energy Technology Data Exchange (ETDEWEB)

Gupta, Ankur [Department of Materials Science and Engineering, Indian Institute of Technology, Kanpur 208016 (India); Advanced Materials Processing and Analysis Center, Department of Materials Science and Engineering, University of Central Florida, Orlando, FL 32826 (United States); Kumar, Vinod [Department of Materials Science and Engineering, Indian Institute of Technology, Kanpur 208016 (India); Department of Metallurgical and Materials Engineering, Malaviya National Institute of Technology, Jaipur 302017 (India); Nair, Jitin [Department of Materials and Metallurgical Engineering, National Institute of Foundry and Forge Technology, Ranchi 834003 (India); Bansal, Ankit [Department of Materials Science and Engineering, Indian Institute of Technology, Kanpur 208016 (India); Tata Steel Ltd., Jamshedpur, Jharkhand 831001 (India); Balani, Kantesh, E-mail: kbalani@iitk.ac.in [Department of Materials Science and Engineering, Indian Institute of Technology, Kanpur 208016 (India)

2015-06-15

Highlights: • Dual phase (α + β) Mg–9Li–7Al–1Sn (LAT971) and Mg–9Li–5Al–3Sn–1Zn (LATZ9531) alloys. • Effective elastic modulus estimated from finite element method (FEM). • Correlation of nanoscale mechanical data with microstress distribution. • Precipitates of Mg–Al–Li act as stress relaxer and Mg–Li–Sn as stress concentrator. • Higher local heterogeneous stress distribution (∼0.6–5.7 GPa) in LATZ9531 alloys. - Abstract: In the recent years, magnesium–lithium (Mg–Li) alloys have attracted considerable attention/interest due to their high strength-to-density ratio and damping characteristic; and have found potential use in structural and biomedical applications. Here the mechanical behavior of novel Mg–9 wt.% Li–7 wt.% Al–1 wt.% Sn (LAT971) and Mg–9 wt.% Li–5 wt.% Al–3 wt.% Sn–1 wt.% Zn (LATZ9531) alloys is reported. Both, as cast and thermomechanically processed alloys have been studied which possess dual phase microstructure. Nanoindentation data have been utilized to envisage the elastic modulus of alloy via various micromechanics models (such as rule of mixtures, Voigt–Reuss, Cox model, Halpin–Tsai and Guth model) in order to estimate the elastic modulus. Object oriented finite element modeling (FEM) has been performed to predict stress distribution under tensile and compressive strain state. Close match between Halpin–Tsai model and FEM results show the abridgment of nano length scale property to evolution of microscopic stress distribution in novel LAT971 and LATZ9531 Mg–Li–Al based alloys.

Origin and migration of trace elements in the surface sediments of Majuro Atoll, Marshall Islands.

Science.gov (United States)

Ito, Lisa; Omori, Takayuki; Yoneda, Minoru; Yamaguchi, Toru; Kobayashi, Ryuta; Takahashi, Yoshio

2018-07-01

The sediments of Majuro Atoll, Marshall Islands, consist of bioclastic materials, including foraminifera and coral debris. The sedimentary depth profiles of elements showed that various elements including zinc (Zn) and copper (Cu) were enriched in the upper layers of the islands of Majuro Atoll. Carbon-14 dating revealed that the sedimentation of the upper layer was completed before 1670 and 542 cal BP in Laura and Calalen, respectively. The enriched elements could be categorized by their origins: (a) terrestrial elements transported as dust (aluminum (Al) and rare earth elements (REEs)); (b) anthropogenic elements (Zn and Cu); and (c) elements supplied by seabirds (phosphorus (P)). From the results of the total amount of Al supplied to sediments for ca. 2000 years, Al in Majuro Atoll was suggested to be airborne origin. The enrichment factors of the elements normalized to Al concentration of continental crust showed that REEs were also transported as dust, while Zn and Cu were mainly of anthropogenic origin. The speciation analysis by X-ray absorption near-edge structure (XANES) showed the presence of Zn-Cu alloys originated from industrial products. It was also revealed that Zn was enriched in the surface due to anthropogenic emission after urbanization on Majuro Atoll and fixed by carbonate and phosphate at the upper layer, which inhibits migration of Zn into the deeper layer and its release to the groundwater and costal water. Hence, the fixation of heavy metals at the surface prevents their exposure to aquatic organisms and residents via fresh groundwater in the island. Copyright © 2018 Elsevier Ltd. All rights reserved.

Finite element modelling of the mechanics of discrete carbon nanotubes filled with ZnS and comparison with experimental observations

KAUST Repository

Monteiro, André O.; Da Costa, Pedro M. F. J.; Cachim, Paulo Barreto

2013-01-01

The mechanical response to a uniaxial compressive force of a single carbon nanotube (CNT) filled (or partially-filled) with ZnS has been modelled. A semi-empirical approach based on the finite element method was used whereby modelling outcomes were closely matched to experimental observations. This is the first example of the use of the continuum approach to model the mechanical behaviour of discrete filled CNTs. In contrast to more computationally demanding methods such as density functional theory or molecular dynamics, our approach provides a viable and expedite alternative to model the mechanics of filled multi-walled CNTs. © 2013 Springer Science+Business Media New York.

Finite element modelling of the mechanics of discrete carbon nanotubes filled with ZnS and comparison with experimental observations

KAUST Repository

Monteiro, André O.

2013-09-25

The mechanical response to a uniaxial compressive force of a single carbon nanotube (CNT) filled (or partially-filled) with ZnS has been modelled. A semi-empirical approach based on the finite element method was used whereby modelling outcomes were closely matched to experimental observations. This is the first example of the use of the continuum approach to model the mechanical behaviour of discrete filled CNTs. In contrast to more computationally demanding methods such as density functional theory or molecular dynamics, our approach provides a viable and expedite alternative to model the mechanics of filled multi-walled CNTs. © 2013 Springer Science+Business Media New York.

MO-Co@N-Doped Carbon (M = Zn or Co): Vital Roles of Inactive Zn and Highly Efficient Activity toward Oxygen Reduction/Evolution Reactions for Rechargeable Zn-Air Battery

Energy Technology Data Exchange (ETDEWEB)

Chen, Biaohua [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 P. R. China; Beijing Key Laboratory of Energy Environmental Catalysis, Beijing University of Chemical Technology, Beijing 100029 P. R. China; He, Xiaobo [Changzhou Institute of Advanced Materials, Beijing University of Chemical Technology, Changzhou 213164 P. R. China; Yin, Fengxiang [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 P. R. China; Beijing Key Laboratory of Energy Environmental Catalysis, Beijing University of Chemical Technology, Beijing 100029 P. R. China; Changzhou Institute of Advanced Materials, Beijing University of Chemical Technology, Changzhou 213164 P. R. China; Wang, Hao [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 P. R. China; Beijing Key Laboratory of Energy Environmental Catalysis, Beijing University of Chemical Technology, Beijing 100029 P. R. China; Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne IL 60439 USA; Liu, Di-Jia [Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne IL 60439 USA; Shi, Ruixing [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 P. R. China; Chen, Jinnan [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 P. R. China; Yin, Hongwei [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 P. R. China

2017-06-14

A highly efficient bifunctional oxygen catalyst is required for practical applications of fuel cells and metal-air batteries, as oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are their core electrode reactions. Here, the MO-Co@ N-doped carbon (NC, M = Zn or Co) is developed as a highly active ORR/OER bifunctional catalyst via pyrolysis of a bimetal metal-organic framework containing Zn and Co, i.e., precursor (CoZn). The vital roles of inactive Zn in developing highly active bifunctional oxygen catalysts are unraveled. When the precursors include Zn, the surface contents of pyridinic N for ORR and the surface contents of Co-N-x and Co3+/Co2+ ratios for OER are enhanced, while the high specific surface areas, high porosity, and high electrochemical active surface areas are also achieved. Furthermore, the synergistic effects between Zn-based and Co-based species can promote the well growth of multiwalled carbon nanotubes (MWCNTs) at high pyrolysis temperatures (>= 700 degrees C), which is favorable for charge transfer. The optimized CoZn-NC-700 shows the highly bifunctional ORR/OER activity and the excellent durability during the ORR/OER processes, even better than 20 wt% Pt/C (for ORR) and IrO2 (for OER). CoZn-NC-700 also exhibits the prominent Zn-air battery performance and even outperforms the mixture of 20 wt% Pt/C and IrO2.

Synthesis of metal-doped Mn-Zn ferrite from the leaching solutions of vanadium slag using hydrothermal method

Science.gov (United States)

Liu, Shiyuan; Wang, Lijun; Chou, Kuochih

2018-03-01

Using vanadium slag as raw material, Metal-doped Mn-Zn ferrites were synthesized by multi-step processes including chlorination of iron and manganese by NH4Cl, selective oxidation of Fe cation, and hydrothermal synthesis. The phase composition and magnetic properties of synthesized metal-doped Mn-Zn ferrite were characterized by X-ray powder diffraction, Raman spectroscopy, transmission electron microscopy (TEM), X-ray photon spectra (XPS) and physical property measurement. It was found that Mn/Zn mole ratio significantly affected the magnetic properties and ZnCl2 content significantly influenced the purity of the phase of ferrite. Synthesized metal-doped Mn-Zn ferrite, exhibiting a larger saturation magnetization (Ms = 60.01 emu/g) and lower coercivity (Hc = 8.9 Oe), was obtained when the hydrothermal temperature was controlled at 200 °C for 12 h with a Mn/Zn mole ratio of 4. The effect of ZnCl2 content, Mn/Zn mole ratio and temperature on magnetic properties of the synthesized metal-doped Mn-Zn ferrite were systemically investigated. This process provided a new insight to utilize resources in the aim of obtaining functional materials.

Mechanical properties investigation on single-wall ZrO2 nanotubes: A finite element method with equivalent Poisson's ratio for chemical bonds

Science.gov (United States)

Yang, Xiao; Li, Huijian; Hu, Minzheng; Liu, Zeliang; Wärnå, John; Cao, Yuying; Ahuja, Rajeev; Luo, Wei

2018-04-01

A method to obtain the equivalent Poisson's ratio in chemical bonds as classical beams with finite element method was proposed from experimental data. The UFF (Universal Force Field) method was employed to calculate the elastic force constants of Zrsbnd O bonds. By applying the equivalent Poisson's ratio, the mechanical properties of single-wall ZrNTs (ZrO2 nanotubes) were investigated by finite element analysis. The nanotubes' Young's modulus (Y), Poisson's ratio (ν) of ZrNTs as function of diameters, length and chirality have been discussed, respectively. We found that the Young's modulus of single-wall ZrNTs is calculated to be between 350 and 420 GPa.

Elements and inorganic ions as source tracers in recent Greenland snow

Science.gov (United States)

Lai, Alexandra M.; Shafer, Martin M.; Dibb, Jack E.; Polashenski, Chris M.; Schauer, James J.

2017-09-01

Atmospheric transport of aerosols leads to deposition of impurities in snow, even in areas of the Arctic as remote as Greenland. Major ions (e.g. Na+, Ca2+, NH4+, K+, SO42-) are frequently used as tracers for common aerosol sources (e.g. sea spray, dust, biomass burning, anthropogenic emissions). Trace element data can supplement tracer ion data by providing additional information about sources. Although many studies have considered either trace elements or major ions, few have reported both. This study determined total and water-soluble concentrations of 31 elements (Al, As, Ca, Cd, Ce, Co, Cr, Dy, Eu, Fe, Gd, K, La, Mg, Mn, Na, Nb, Nd, Pb, Pr, S, Sb, Si, Sm, Sn, Sr, Ti, V, U, Y, Zn) in shallow snow pits at 22 sampling sites in Greenland, along a transect from Summit Station to sites in the northwest. Black carbon (BC) and inorganic ions were measured in colocated samples. Sodium, which is typically used as a tracer of sea spray, did not appear to have any non-marine sources. The rare earth elements, alkaline earth elements (Mg, Ca, Sr), and other crustal elements (Fe, Si, Ti, V) were not enriched above crustal abundances relative to Al, indicating that these elements are primarily dust sourced. Calculated ratios of non-sea salt Ca (nssCa) to estimated dust mass affirm the use of nssCa as a dust tracer, but suggest up to 50% uncertainty in that estimate in the absence of other crustal element data. Crustal enrichment factors indicated that As, Cd, Pb, non-sea-salt S, Sb, Sn, and Zn were enriched in these samples, likely by anthropogenic sources. Principal component analysis indicated more than one crustal factor, and a variety of factors related to anthropogenically enriched elements. Analysis of trace elements alongside major tracer ions does not change interpretation of ion-based source attribution for sources that are well-characterized by ions, but is valuable for assessing uncertainty in source attribution and identifying sources not represented by major ions.

Preparation of cadmium-doped ZnO thin films by SILAR and their ...

Indian Academy of Sciences (India)

Cadmium-doped zinc oxide (Cd : ZnO) thin films were deposited from sodium zincate bath .... of complex ion on the substrate followed by reaction of the .... Intensity (a.u.). 0. 500 .... trum confirmed the presence of Zn, O and Cd elements in the.

Growth and Characterization of Indium Doped ZnO Nano wires Using Thermal Evaporation Method

International Nuclear Information System (INIS)

Abrar Ismardi; Dee, C.F.; Majlis, B.Y.

2011-01-01

Indium doped ZnO nano wires were grown on silicon substrate using vapor thermal deposition method without using any catalyst. Morphological structures were extensively investigated using field emission scanning electron microscopy (FESEM) and show that the nano wires have uniformly hexagonal nano structures with diameters less than 100 nm and lengths from one to a few microns. The sample was measured for elemental composition with energy dispersive X-ray (EDX) spectroscopy, Zn, In and O elements were found on the sample. XRD spectrum of indium doped ZnO nano wires revealed that the nano wires have a high crystalline structure. (author)

Bactericidal impact of Ag, ZnO and mixed AgZnO colloidal nanoparticles on H37Rv Mycobacterium tuberculosis phagocytized by THP-1 cell lines.

Science.gov (United States)

Jafari, Alireza; Mosavari, Nader; Movahedzadeh, Farahnaz; Nodooshan, Saeedeh Jafari; Safarkar, Roya; Moro, Rossella; Kamalzadeh, Morteza; Majidpour, Ali; Boustanshenas, Mina; Mosavi, Tahereh

2017-09-01

The purpose of this research project was to infection of human macrophages (THP-1) cell lines by H 37 Rv strain of Mycobacterium tuberculosis (H 37 RvMTB) and find out the ratio/dilution of mixture silver (Ag NPs) and zinc oxide nanoparticles (ZnO NPs) whose ability to eliminate phagocytized bacteria compared to rifampicin. The colloidal Ag NPs and ZnO NPs were synthesized and their characteristics were evaluated. The THP-1 cell lines were infected with different concentration of H 37 RvMTB. Next, the infected cells were treated with different ratios/dilutions of Ag NPs, ZnO NPs and rifampicin. The THP-1 were lysed and were cultured in Lowenstein-Jensen agar medium, for eight weeks. The TEM and AFM images of NPs and H 37 RvMTB were supplied. It is observed that Ag NPs, 2 Ag :8 ZnO and 8 Ag :2 ZnO did not have any anti-tubercular effects on phagocytized H 37 RvMTB. Conversely, ZnO NPs somehow eliminated 18.7 × 10 4  CFU ml -1 of H 37 RvMTB in concentration of ∼ 0.468 ppm. To compare with 40 ppm of rifampicin, ∼ 0.663 ppm of 5 Ag :5 ZnO had the ability to kill of H 37 RvMTB, too. Based on previous research, ZnO NPs had strong anti-tubercular impact against H 37 RvMTB to in-vitro condition, but it was toxic in concentration of ∼ 0.468 ppm to both of THP-1 and normal lung (MRC-5) cell lines. It also seems that 5 Ag :5 ZnO is justified because in concentration of ∼ 0.663 ppm of 5 Ag :5 ZnO , phagocytized H 37 RvMTB into the THP-1 had died without any toxicity effects against THP-1 and also MRC-5 cell lines. It is obvious that the mixture of colloidal silver and zinc oxide NPs with ratio of 5 Ag :5 ZnO would be trustworthy options as anti-tubercular nano-drugs in future researches. Copyright © 2017. Published by Elsevier Ltd.

Nuclear microprobe investigation into the trace elemental contents of carotid artery walls of apolipoprotein E deficient mice

International Nuclear Information System (INIS)

Ren Minqin; Huang En; Beck, Konstanze; Rajendran, Reshmi; Wu, Ben J.; Halliwell, Barry; Watt, Frank; Stocker, Roland

2007-01-01

Atherosclerosis is a progressive disease that causes lesions in large and medium-sized arteries. There is increasing evidence that the function of vascular endothelial cells is impaired by oxidation reactions, and that metal ions may participate in these processes. The nuclear microscopy facility in NUS, which has the ability to focus a 2 MeV proton beam down to sub micron spot sizes, was used to investigate the trace elemental changes (e.g. Zn and Fe) in atherosclerotic lesions in the common carotid artery of apolipoprotein E deficient mice fed a high fat diet. In this preliminary study, which is part of a larger study to investigate the effects of probucol on carotid artery atherosclerosis, two sets of mice were used; a test set fed a high fat diet +1% probucol, and a control set which was fed a high fat diet only. The results show that the Zn/Fe ratio was significantly higher in the media of arteries of probucol treated animals without overlying lesion (4.3) compared to the media with overlying lesion (1.3) (p = 0.004) for test mice. For the control mice, the arterial Zn/Fe ratio was 1.8 for media without overlying lesion, compared with 1.0 for media with overlying lesion (p = 0.1). Thus, for media without overlying lesion, the Zn/Fe ratio was significantly higher (p = 0.009) in probucol-treated (4.3) than control mice (1.8), whereas there was little difference in the ratios between the two groups in media with overlying lesion (1.3 compared with 1.0). These preliminary results are consistent with the idea that the levels of iron and zinc concentrations within the artery wall may influence the formation of atherosclerotic plaque in the carotid artery

The study of major, trace and rare earth elements geochemistry in Shahrestanak Mn deposit, south of Qom: Implications for genesis

Directory of Open Access Journals (Sweden)

Mohammad Maanijou

2015-04-01

Full Text Available Introduction The Shahrestanak Mn deposit is located in southern Qom province, 12 km southwest of the city of Kahak. Based on geological-structural divisions of Iran, the deposit belongs to central volcanic belt or Urumieh-Dokhtar zone. The Venarch deposit is one the most important known manganese deposits in Iran. The Sharestanak and Venarch deposits are spatially and temporally related to each other, and have similar geology, mineral texture and structure, host rocks, relationships with faults, and depositional environment. So, their magmatism and deposition conditions can be related to each other. Since no systematic study on the Shahrestanak deposit had been performed before discussing its geological and geochemical characteristics, here it is being attempted to study the geology, petrography, geochemistry of major, minor and trace elements, and Rare Earth Elements (REE of ore, to distinguish the depositional environments and genesis of this deposit and to compare REE of ore in this deposit with other deposits. Sampling and method of study Fourteen samples of manganese ore were selected for geochemical study and analyzing of major, minor, trace elements and REE by ICP-AES and ICP-MS and were sent to SGS Co., Toronto. Detection limits for major elements and trace elements are 0.01% and 0.05ppm, respectively. Result and discussion The deposit is characterized by various lithology and stratigraphy units, consist of: 1 Middle to -Upper Eocene volcano-sedimentary rocks, 2 Oligocene lower red conglomerate and sandstone, 3 Oligo-Miocene limestone and marl (Qom Formation, and 4 Eocene and Lower Miocene basic to intermediate dykes. The most abundant minerals of the deposit are braunite, hausmannite, pyrolusite, and manganite. Evidences such as high Mn/Fe (11.33 and Si/Al (4.86 ratios, low contents of trace elements specially Co (11.40 ppm, Ni (24 ppm, Cu (81.85 ppm, and Ce, with high amounts of SiO2, Mn, Fe, Ba, Zn, As and Sr, all represent

Seasonal variation of major elements (Ca, Mg) and trace metals (Fe, Cu, Zn, Mn) and cultured mussel Perna viridis L. and seawater in the Dona Paula Bay, Goa

Digital Repository Service at National Institute of Oceanography (India)

Rivonker, C.U.; Parulekar, A.H.

The major elements and trace metals were analysed from nussel tissue and the seawater taken from three depths (0, 5 and 9 meters) from the culture site. Range of variation in Ca, Mg, Fe, Cu, Zn and Mn were 226-399; 708-1329; 0.005-0.084; BDL-0...

La5Zn2Sn

Directory of Open Access Journals (Sweden)

Igor Oshchapovsky

2011-11-01

Full Text Available A single crystal of pentalanthanum dizinc stannide, La5Zn2Sn, was obtained from the elements in a resistance furnace. It belongs to the Mo5SiB2 structure type, which is a ternary ordered variant of the Cr5B3 structure type. The space is filled by bicapped tetragonal antiprisms from lanthanum atoms around tin atoms sharing their vertices. Zinc atoms fill voids between these bicapped tetragonal antiprisms. All four atoms in the asymmetric unit reside on special positions with the following site symmetries: La1 (..m; La2 (4/m..; Zn (m.2m; Sn (422.

SIMS depth profiling of rubber-tyre cord bonding layers prepared using 64Zn depleted ZnO

International Nuclear Information System (INIS)

Fulton, W.S.; Sykes, D.E.; Smith, G.C.

2006-01-01

Zinc oxide and copper/zinc sulphide layers are formed during vulcanisation and moulding of rubber to brass-coated steel tyre reinforcing cords. Previous studies have described how zinc diffuses through the rubber-brass interface to form zinc sulphide, and combines with oxygen to create zinc oxide during dezincification. The zinc is usually assumed to originate in the brass of the tyre cord, however, zinc oxide is also present in the rubber formulation. We reveal how zinc from these sources is distributed within the interfacial bonding layers, before and after heat and humidity ageing. Zinc oxide produced using 64 Zn-isotope depleted zinc was mixed in the rubber formulation in place of the natural ZnO and the zinc isotope ratios within the interfacial layers were followed by secondary ion mass spectroscopy (SIMS) depth profiling. Variations in the relative ratios of the zinc isotopes during depth profiling were measured for unaged, heat-aged and humidity-aged wire samples and in each case a relatively large proportion of the zinc incorporated into the interfacial layer as zinc sulphide was shown to have originated from ZnO in the rubber compound

Single-Crystal Mesoporous ZnO Thin Films Composed of Nanowalls

KAUST Repository

Wang, Xudong

2009-02-05

This paper presents a controlled, large scale fabrication of mesoporous ZnO thin films. The entire ZnO mesoporous film is one piece of a single crystal, while high porosity made of nanowalls is present. The growth mechanism was proposed in comparison with the growth of ZnO nanowires. The ZnO mesoporous film was successfully applied as a gas sensor. The fabrication and growth analysis of the mesoporous ZnO thin film gi ve general guidance for the controlled growth of nanostructures. It also pro vides a unique structure with a superhigh surface-to-volume ratio for surface-related applications. © 2009 American Chemical Society.

Determination of toxic and essential elements in seafood

International Nuclear Information System (INIS)

Surtipanti, S.; Suwirma, S.; Yumiarti, S.; Yune Mellawati, T.

1990-01-01

Indonesia has only a list of the maximum permissible concentration of toxic elements in water stated in a national legislation. Therefore, it is important to study the toxic elements content in fish and shellfish, because these marine organisms are good biological indicators. The interesting elements to be analyzed are toxic elements, i.e. As, Cd, Cr, Hg, Pb, Sb and Se, and essential elements, i.e., Zn and Cu. As, Cr, Hg, Sb, Se and Zn can be determined by Neutron Activation Analysis (NAA), while Cd, Cu and Pb by Atomic Absorption Spectrometry (AAS). The determination of such elements in foodstuff i.e. rice, corn, green pea, wheat, vegetables, fruits, tea and coffee have been done previously. The major purpose of this work is to know whether the concentration of toxic elements in marine organisms is approaching or exceeding the maximum permissible concentration as stated by International legislation. 7 refs, 5 tabs

Cooperative cytotoxic activity of Zn and Cu in bovine serum albumin-conjugated ZnS/CuS nano-composites in PC12 cancer cells

International Nuclear Information System (INIS)

Wang, Hua-Jie; Yu, Xue-Hong; Wang, Cai-Feng; Cao, Ying

2013-01-01

Series of self-assembled and mono-dispersed bovine serum albumin (BSA)-conjugated ZnS/CuS nano-composites with different Zn/Cu ratios had been successfully synthesized by a combination method of the biomimetic synthesis and ion-exchange strategy under the gentle conditions. High-resolution transmission electron microscopy observation, Fourier transform infrared spectra and zeta potential analysis demonstrated that BSA-conjugated ZnS/CuS nano-composites with well dispersity had the hierarchical structure and BSA was a key factor to control the morphology and surface electro-negativity of final products. The real-time monitoring by atomic absorption spectroscopy and powder X-ray diffraction revealed that the Zn/Cu ratio of nano-composites could be controlled by adjusting the ion-exchange time. In addition, the metabolic and morphological assays indicated that the metabolic proliferation and spread of rat pheochromocytoma (PC12) cells could be inhibited by nano-composites, with the high anti-cancer activity at a low concentration (4 ppm). What were more important, Zn and Cu in nano-composites exhibited a positive cooperativity at inhibiting cancer cell functions. The microscope observation and biochemical marker analysis clearly revealed that the nano-composites-included lipid peroxidation and disintegration of membrane led to the death of PC12 cells. Summarily, the present study substantiated the potential of BSA-conjugated ZnS/CuS nano-composites as anti-cancer drug

Cooperative cytotoxic activity of Zn and Cu in bovine serum albumin-conjugated ZnS/CuS nano-composites in PC12 cancer cells

Energy Technology Data Exchange (ETDEWEB)

Wang, Hua-Jie, E-mail: wanghuajie972001@163.com; Yu, Xue-Hong; Wang, Cai-Feng; Cao, Ying, E-mail: caoying1130@sina.com [Henan Normal University, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, College of Chemistry and Chemical Engineering (China)

2013-11-15

Series of self-assembled and mono-dispersed bovine serum albumin (BSA)-conjugated ZnS/CuS nano-composites with different Zn/Cu ratios had been successfully synthesized by a combination method of the biomimetic synthesis and ion-exchange strategy under the gentle conditions. High-resolution transmission electron microscopy observation, Fourier transform infrared spectra and zeta potential analysis demonstrated that BSA-conjugated ZnS/CuS nano-composites with well dispersity had the hierarchical structure and BSA was a key factor to control the morphology and surface electro-negativity of final products. The real-time monitoring by atomic absorption spectroscopy and powder X-ray diffraction revealed that the Zn/Cu ratio of nano-composites could be controlled by adjusting the ion-exchange time. In addition, the metabolic and morphological assays indicated that the metabolic proliferation and spread of rat pheochromocytoma (PC12) cells could be inhibited by nano-composites, with the high anti-cancer activity at a low concentration (4 ppm). What were more important, Zn and Cu in nano-composites exhibited a positive cooperativity at inhibiting cancer cell functions. The microscope observation and biochemical marker analysis clearly revealed that the nano-composites-included lipid peroxidation and disintegration of membrane led to the death of PC12 cells. Summarily, the present study substantiated the potential of BSA-conjugated ZnS/CuS nano-composites as anti-cancer drug.

Main and trace element analysis of urinary stones by means of neutron activation and X-ray fluorescence

International Nuclear Information System (INIS)

Buehling, A.; Riotte, H.G.

1978-01-01

Metallosis, a tissue reaction to metal implants which is caused by corrosion of the implanted metal caused by body liquids, makes activation analysis interesting as a method to determine trace element distributions in tissue and organs. Osteosynthesis of the eft hind leg was carried out in 30 rabbits. The bone fragments were fixated with V4A steel plates and 3-4 screws each. One xear after implantation a total of 350 samples was taken in contact tissue, muscles, lymphatic tissue, kidneys, liver, lungs, and heart and investigated by instrumental neutron activation analysis. The elements Na, K, Cr, Fe, Co, Ni, Zn, Se, Rb, Mo, Cs, Ta, and W were quantitatively determinde. Four animals of the same strain hald under the same condition were used as controls. It was found that the alloy components of the V4A steel implants burden the body even at considerable distance. Of particular interest are the findings for lympatic tissue, liver and kidneys, which indicate tendencies of Cr and Ni accumulation. Element correlations showed that the tissues take up the metal ions in nearly constant ratios, with the exception of iron. The concentrations of other essential elements like Zn, Se, Rb, and k are also influenced by the implants. (orig.) [de

ZnGeP sub 2 crystals for infrared laser radiation frequency conversion

CERN Document Server

Andreev, Y M; Gribenyukov, A I; Korotkova, V V

1998-01-01

In this parer, we present some recent results on integrated studies concerned with different aspects of ZnGeP sub 2 crystal technology: synthesis, growth, and post-growth treatment. High-yield two-temperature synthesis and subsequent growth of ZnGeP sub 2 crystals are considered. By X-Ray phase analysis it has been found that two-temperature synthesis of ZnGeP sub 2 is realized through binary zinc and germanium phosphides formed at the Zn-Ge mixture temperature of about 900 .deg. C and the P pressure of 7 approx 10 atm. Using the heat-balance equation, a ratio of the thermal conductivity in the solid to that in the liquid ZnGeP sub 2 near the melting point has been determined. The value of the determined ratio is K sub l /K sub s approx =2.3. Analysis of the most favored crystallographic directions for ZnGeP sub 2 growth has been performed. These directions are [116], [132] and [102]. Data for optical absorption of the as-grown and the annealed ZnGeP sub 2 crystals are also presented.

Improving Stiffness-to-weight Ratio of Spot-welded Structures based upon Nonlinear Finite Element Modelling

Science.gov (United States)

Zhang, Shengyong

2017-07-01

Spot welding has been widely used for vehicle body construction due to its advantages of high speed and adaptability for automation. An effort to increase the stiffness-to-weight ratio of spot-welded structures is investigated based upon nonlinear finite element analysis. Topology optimization is conducted for reducing weight in the overlapping regions by choosing an appropriate topology. Three spot-welded models (lap, doubt-hat and T-shape) that approximate “typical” vehicle body components are studied for validating and illustrating the proposed method. It is concluded that removing underutilized material from overlapping regions can result in a significant increase in structural stiffness-to-weight ratio.

Elemental composition by EDXRF of marine sponges from the Berlengas portuguese natural park - western portuguese coast

International Nuclear Information System (INIS)

Araujo, Maria Fatima; Conceicao, Ana; Barbosa, Teresa

2001-01-01

Marine sponges are sedentary and unselective filter-feeding metazoans, which are nowadays represented by more than six thousand species with the Demospongiae being the most representative, inhabiting all aquatic environments. Due to their way of feeding, by filtering large amounts of water, these benthic organisms are particularly exposed to pollutants. Previous studies have demonstrated their aptitude in being used as environmental monitors. Besides, some authors have evidenced a selective bio-accumulation capability for some transition elements (e.g. Ni, Zn) which is dependent on the species. The present work aims at the investigation of marine sponges collected at the Berlengas Islands located at Western Portuguese Coastal area. These islands constitute a National Park with controlled access and low signal of anthropogenic influences, being a nearly ideal habitat to evaluate a possible selective bio-accumulation. Thirty-five sponges collected in August 1998, at the Berlengas National Park were classified and analysed by Energy-Dispersive X-Ray Fluorescence Spectrometry (EDXRF). The major, minor and some trace elements: Al, Si, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Zr, I and Pb were determined. Besides, sediment samples were also taken from the area to assess some lithological influence on the sponge composition. Due to the high percentage of elements that do not emit characteristic X-ray lines, absorption corrections for quantitative calculations were carried out taking into account the ratio between the inelastic and elastic scattered incident radiation of compounds and standard reference materials, from a silver secondary target. A lithological influence on the sponge major elemental composition is demonstrated. The absence of any trace metal contamination was confirmed and a clear selective bio-accumulation in some trace elements, such as Ni, Zn and As was detected

Transparent conducting thin films by co-sputtering of ZnO-ITO targets

Energy Technology Data Exchange (ETDEWEB)

Carreras, Paz; Antony, Aldrin; Roldan, Ruben; Nos, Oriol; Frigeri, Paolo Antonio; Asensi, Jose Miguel; Bertomeu, Joan [Grup d' Energia Solar, Universitat de Barcelona (Spain)

2010-04-15

Transparent and conductive Zn-In-Sn-O (ZITO) amorphous thin films have been deposited at room temperature by the rf magnetron co-sputtering of ITO and ZnO targets. Co-sputtering gives the possibility to deposit multicomponent oxide thin films with different compositions by varying the power to one of the targets. In order to make ZITO films with different Zn content, a constant rf power of 50 W was used for the ITO target, where as the rf power to ZnO target was varied from 25 W to 150 W. The as deposited films showed an increase in Zn content ratio from 17 to 67% as the power to ZnO target was increased from 25 to 150 W. The structural, electrical and optical properties of the as deposited films are reported. The films showed an average transmittance over 80% in the visible wavelength range. The electrical resistivity and optical band gap of the ZITO films were found to depend on the Zn content in the film. The ZITO films deposited at room temperature with lower Zn content ratios showed better optical transmission and electrical properties compared to ITO film. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Shell Thickness Dependence of Interparticle Energy Transfer in Core-Shell ZnSe/ZnSe Quantum Dots Doping with Europium

Science.gov (United States)

Liu, Ni; Li, Shuxin; Wang, Caifeng; Li, Jie

2018-04-01

Low-toxic core-shell ZnSe:Eu/ZnS quantum dots (QDs) were prepared through two steps in water solution: nucleation doping and epitaxial shell grown. The structural and morphological characteristics of ZnSe/ZnS:Eu QDs with different shell thickness were explored by transmission electron microscopy (TEM) and X-ray diffraction (XRD) results. The characteristic photoluminescence (PL) intensity of Eu ions was enhanced whereas that of band-edge luminescence and defect-related luminescence of ZnSe QDs was decreased with increasing shell thickness. The transformation of PL intensity revealed an efficient energy transfer process between ZnSe and Eu. The PL intensity ratio of Eu ions ( I 613) to ZnSe QDs ( I B ) under different shell thickness was systemically analyzed by PL spectra and time-resolved PL spectra. The obtained results were in agreement with the theory analysis results by the kinetic theory of energy transfer, revealing that energy was transmitted in the form of dipole-electric dipole interaction. This particular method of adjusting luminous via changing the shell thickness can provide valuable insights towards the fundamental understanding and application of QDs in the field of optoelectronics.

Synthesis, characterization and in vivo evaluation of [(62)Zn]-benzo-δ-sultam complex as a possible pet imaging agent.

Science.gov (United States)

Ghandi, Mehdi; Feizi, Shahzad; Ziaie, Farhood; Fazaeli, Yousef; Notash, Behrooz

2014-11-01

The development of a new tracer based on the cyclic sulfonamides (sultams) was investigated. 3-(Methoxy-phenyl-methyl)-1,6-dimethyl-1H benzo[c][1,2] thiazine 2,2-dioxide (benzo-δ-sultam) was synthesized and characterized by elemental analysis, FT-IR spectroscopy and single crystal X-ray structure determination. The prepared cyclic sulfonamide was labeled with non-commercial (62)Zn radioisotope for fast in vivo targeting and Coincidence imaging purposes (radiochemical purity 97 % ITLC, 96 % HPLC, specific activity 20-23 GBq/mmol). In vivo biodistribution of the final complex was investigated in Sprague Dawley(®) rats bearing fibro sarcoma tumor after 2, 4 and 8 h post injection and compared with free Zn(+2) cation. Using instant paper chromatography method, the physicochemical properties of labeled compounds were found sufficiently stable in organic phases, e.g. a human serum, to be reliably used in bioapplications. The complex exhibited a rapid as well as high tumor uptake (tumor to blood ratio 4.38 and tumor to muscle ratio 9.63) resulting in an efficient tumor targeting agent.

Characteristics of trace elements and lead isotope ratios in PM2.5 from four sites in Shanghai

International Nuclear Information System (INIS)

Chen Jianmin; Tan Mingguang; Li Yulan; Zheng Jian; Zhang Yuanmao; Shan Zuci; Zhang Guilin; Li Yan

2008-01-01

PM 2.5 samples were collected in Shanghai at four sites with different typical land-uses. The sampling was done concurrently once per month from April 2004 to April 2005, and the ambient mass concentration, the elemental composition and the stable lead isotope ratios in these PM 2.5 samples were determined. The annual average concentrations of PM 2.5 samples at each site were 84 ± 30, 65 ± 20, 55 ± 18, and 41 ± 10 μg m -3 , respectively, indicating there were severe air pollution levels in Shanghai. The enrichment factor was calculated for each element and the comparison and discussion of elements with significant anthropogenic contributions between Shanghai and Tokyo suggested that the major source of PM 2.5 in Shanghai was not traffic-derived emissions, but the stationary industrial contribution emitted from coal use. Moreover, the analysis of stable lead isotope ratios revealed only a slight difference within the samples at the four sites which fell well within the scope of coal composition difference, further confirming that the contribution from stationary industrial emissions to atmospheric lead pollution of PM 2.5 was very substantial in Shanghai

EDTA-assisted synthesis of rose-like ZnO architectures

Energy Technology Data Exchange (ETDEWEB)

Li, Zhen [Institute of Nanochemistry and Nanobiology, Shanghai University, Shanghai 201800 (China); Shanghai Applied Radiation Institute, Shanghai University, Shanghai 201800 (China); Fang, Yaoguo [Institute of Nanochemistry and Nanobiology, Shanghai University, Shanghai 201800 (China); Peng, Liwei; Wu, Minghong [Shanghai Applied Radiation Institute, Shanghai University, Shanghai 201800 (China); Pan, Dengyu

2010-10-15

Rose-like ZnO nanostructures were prepared by a low-temperature solution route with assistance of ethylenediaminetetraacetic acid disodium (EDTA-2Na). The morphology of ZnO nanostructures was found to change from nanowire arrays to rose- and tower-like architectures with increasing the molar ratio of EDTA-2Na/Zn{sup 2+}. Also, the shape evolution of ZnO nanostructures with time was observed from flat nanosheets to wrinkled nanosheets and to rose-like nanostructures. EDTA-2Na as a strong complexing agent was found to play a key role in the shape evolution. Photoluminescence spectra show that the rose-like ZnO architectures have more defects than the nanowire arrays. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Bk and Cf chromatographic separation and 249Bk/248Cm and 249Cf/248Cm elemental ratios determination by inductively coupled plasma quadrupole mass spectrometry

International Nuclear Information System (INIS)

Gourgiotis, A.; Isnard, H.; Nonell, A.; Aubert, M.; Stadelmann, G.; Dupont, E.; AlMahamid, I.; Tiang, G.; Rao, L.; Lukens, W.; Cassette, P.; Panebianco, S.; Letourneau, A.; Chartier, F.

2013-01-01

The French Atomic Energy Commission has carried out several experiments for the study of minor-actinide transmutation processes in high intensity thermal neutron flux. In this context a Cm sample enriched in 248 Cm (97%) was irradiated in a thermal neutron flux at the High Flux Reactor (HFR) of the Laue-Langevin Institute (ILL). The precise and accurate determination of Cf isotope ratios and of 249 Bk/ 248 Cm and 249 Cf/ 248 Cm elemental ratios in the 248 Cm irradiated sample is crucial for the calculation of actinide neutron capture cross-sections.This work describes an analytical procedure for the separation and the isotope ratio measurement of Bk and Cf in the irradiated sample.The Bk and Cf separation is based on a lanthanides separation protocol previously developed by the laboratory. Well-defined retention times for Bk and Cf were obtained by coupling the Ionic Chromatography (IC) with an ICP-QMS. All conditions of element separation by IC and the different steps of the analytical protocol in order to obtain the isotopic and elemental ratios are presented. Relative uncertainties of Cf isotopic ratios range from 0.3% to 0.5% and the uncertainty of the 249 Bk/ 248 Cm and 249 Cf/ 248 Cm elemental ratios are respectively 6.1% and 3.2%.This level of uncertainty for both isotopic and elemental ratios is in perfect agreement with the requirement for transmutation studies. (authors)

Effects of Piezoelectric Potential of ZnO on Resistive Switching Characteristics of Flexible ZnO/TiO2 Heterojunction Cells

Science.gov (United States)

Li, Hongxia; Zhou, You; Du, Gang; Huang, Yanwei; Ji, Zhenguo

2018-03-01