WorldWideScience

Sample records for wet chemical deposition

  1. Modeled Wet Nitrate Deposition

    Data.gov (United States)

    U.S. Environmental Protection Agency — Modeled data on nitrate wet deposition was obtained from Dr. Jeff Grimm at Penn State Univ. Nitrate wet depostion causes acidification and eutrophication of surface...

  2. Wet chemical deposition of single crystalline epitaxial manganite thin films with atomically flat surface

    International Nuclear Information System (INIS)

    Mishra, Amita; Dutta, Anirban; Samaddar, Sayanti; Gupta, Anjan K.

    2013-01-01

    We report the wet chemical deposition of single crystalline epitaxial thin films of the colossal magneto-resistive manganite La 0.67 Sr 0.33 MnO 3 on the lattice-matched (001)-face of a La 0.3 Sr 0.7 Al 0.65 Ta 0.35 O 3 substrate. Topographic images of these films taken with a scanning tunneling microscope show atomically flat terraces separated by steps of monatomic height. The resistivity of these films shows an insulator-metal transition at 310 K, nearly coincident with the Curie temperature of 340 K, found from magnetization measurements. The films show a magnetoresistance of 7% at 300 K and 1.2 T. Their saturation magnetization value at low temperatures is consistent with that of the bulk. - Highlights: ► Wet chemical deposition of La 0.67 Sr 0.33 MnO 3 (LSMO) on a lattice-matched substrate. ► Single crystalline epitaxial LSMO films obtained. ► Flat terraces separated by monatomic steps observed by scanning tunneling microscope

  3. Oxidation Kinetics of Chemically Vapor-Deposited Silicon Carbide in Wet Oxygen

    Science.gov (United States)

    Opila, Elizabeth J.

    1994-01-01

    The oxidation kinetics of chemically vapor-deposited SiC in dry oxygen and wet oxygen (P(sub H2O) = 0.1 atm) at temperatures between 1200 C and 1400 C were monitored using thermogravimetric analysis. It was found that in a clean environment, 10% water vapor enhanced the oxidation kinetics of SiC only very slightly compared to rates found in dry oxygen. Oxidation kinetics were examined in terms of the Deal and Grove model for oxidation of silicon. It was found that in an environment containing even small amounts of impurities, such as high-purity Al2O3 reaction tubes containing 200 ppm Na, water vapor enhanced the transport of these impurities to the oxidation sample. Oxidation rates increased under these conditions presumably because of the formation of less protective sodium alumino-silicate scales.

  4. Comparison of wet-only and bulk deposition at Chiang Mai (Thailand) based on rainwater chemical composition

    Science.gov (United States)

    Chantara, Somporn; Chunsuk, Nawarut

    The chemical composition of 122 rainwater samples collected daily from bulk and wet-only collectors in a sub-urban area of Chiang Mai (Thailand) during August 2005-July 2006 has been analyzed and compared to assess usability of a cheaper and less complex bulk collector over a sophisticated wet-only collector. Statistical analysis was performed on log-transformed daily rain amount and depositions of major ions for each collector type. The analysis of variance (ANOVA) test revealed that the amount of rainfall collected from a rain gauge, bulk collector and wet-only collector showed no significant difference ( ∝=0.05). The volume weight mean electro-conductivity (EC) values of bulk and wet-only samples were 0.69 and 0.65 mS/m, respectively. The average pH of the samples from both types of collectors was 5.5. Scatter plots between log-transformed depositions of specific ions obtained from bulk and wet-only samples showed high correlation ( r>0.91). Means of log-transformed bulk deposition were 14% (Na + and K +), 13% (Mg 2+), 7% (Ca 2+), 4% (NO 3-), 3% (SO 42- and Cl -) and 2% (NH 4+) higher than that of wet-only deposition. However, multivariate analysis of variance (MANOVA) revealed that ion depositions obtained from bulk and wet-only collectors were not significantly different ( ∝=0.05). Therefore, it was concluded that a bulk collector can be used instead of a wet-only collector in a sub-urban area.

  5. European wet deposition maps based on measurements

    NARCIS (Netherlands)

    Leeuwen EP van; Erisman JW; Draaijers GPJ; Potma CJM; Pul WAJ van; LLO

    1995-01-01

    To date, wet deposition maps on a European scale have been based on long-range transport model results. For most components wet deposition maps based on measurements are only available on national scales. Wet deposition maps of acidifying components and base cations based on measurements are needed

  6. Influence of Air Pollution on Chemical Quality of Wet Atmospheric Deposition: a Case Study in Urmia, Iran

    Directory of Open Access Journals (Sweden)

    Yaghoub Hajizadeh

    2017-10-01

    Full Text Available Increased combustion of fossil fuel owing to the energy requirement is a main cause of air pollution throughout the world. Atmospheric precipitation is considered as a major water resource for indoor, municipal, industrial and agricultural uses. This study was aimed to evaluate the effect of air pollution on chemical quality of rain and snow in Urmia, a city in northwest of Iran. Sampling was performed during the wet seasons from October to March at six sampling stations in different locations of the city. Acidity, alkalinity, NO3- , SO42-, Cl- and pH contents of the collected samples were analyzed. All samples showed a pH value of more than 6.8, and lower acidity than alkalinity, therefore, the precipitations were not acidic. Maximum concentrations of SO42- and NO3- in the samples were 5 and 8.8mg/L, respectively. Chloride was varied from 1 to 11.5 mg/L with the highest measures observing in autumn. According to the results, concentrations of the analyzed parameters in wet precipitations in Urmia were within the natural ranges except chloride ions, which was higher than its common level in the atmosphere. This phenomenon may be the result of desert dusts which transfers by wind from the west border to Iran. ‎

  7. ROE Wet Sulfate Deposition 2009-2011

    Data.gov (United States)

    U.S. Environmental Protection Agency — The raster data represent the amount of wet sulfate deposition in kilograms per hectare from 2009 to 2011. Summary data in this indicator were provided by EPA’s...

  8. Facts and fallacies in wet deposition modelling

    International Nuclear Information System (INIS)

    ApSimon, H.M.; Goddard, A.J.H.; Manning, P.M.; Simms, K.

    1987-01-01

    Following a reactor accident, relatively high contamination at ground level can occur, even at quite long distances from the source, if the pollutant cloud encounters intense precipitation. To estimate such contamination and its extent properly, it is necessary to take into account the spatial and temporal structure of rain patterns and their motion. Currently, models of wet deposition are rather crude. Source meteorology is usually used and is clearly inadequate. Furthermore, no allowance is made for the dynamic nature of rainfall, which occurs as a result of vertical air motions and convergence; nor for the different scavenging mechanism operating in and below cloud. Meteorological information available on these aspects of wet deposition is reviewed, and their importance and inclusion in modelling and prediction of resulting ground contamination is indicated. Some of the pitfalls of simple modelling procedures are illustrated. (author)

  9. Characteristics of Wet Deposition in Japan

    Science.gov (United States)

    Iwasaki, A.; Arakaki, T.

    2017-12-01

    Acid deposition survey in Japan has started since 1991 by Japan Environmental Laboratories Association (JELA). The JELA has about 60 monitoring sites for wet deposition including remote, rural and urban area. The measured constituents of wet deposition are; precipitation, pH, electric conductivity, major Anions, and major Cations. From those data, we analyze spatial and temporal variations of wet deposition components in Japan. Among the 60 monitoring sites, 39 sampling sites were selected in this study, which have kept sampling continuously between 2003JFY and 2014JFY. All samples were collected by wet-only samplers. To analyze area characteristics, all the areas were divided into 6 regions; Northern part of Japan (NJ), Facing the Japan Sea (JS), Eastern part of Japan (EJ), Central part of Japan (CJ), Western part of Japan (WJ) and Southern West Islands (SW). NO3- and non-sea-salt-SO42- (nss-SO42-) are major components of rain acidification. Especially, between December and February (winter) the air mass from west affected the temporal variations of those acid components and the concentrations were higher in JS and WJ regions than those in other regions. Japanese ministry of the Environment reported that mixing ratio of NO2 in Japan has been less than 0.04ppm since 1976, and that of SO2 has been less than 0.02ppm since 1978. Their concentrations in Japan have remained flat or slowly decreased recently. However the temporal variations of NO3-/nss-SO42- ratio in winter in JS region were significantly increased on average at 2.2% y-1 from 2003JFY to 2014JFY. The results suggest that long-range transboundary air pollutants increased NO3- concentrations and NO3-/nss-SO42- ratio.

  10. Surface passivation by Al2O3 and a-SiNx: H films deposited on wet-chemically conditioned Si surfaces

    NARCIS (Netherlands)

    Bordihn, S.; Mertens, V.; Engelhart, P.; Kersten, K.; Mandoc, M.M.; Müller, J.W.; Kessels, W.M.M.

    2012-01-01

    The surface passivation of p- and n-type silicon by different chemically grown SiO2 films (prepared by HNO3, H2SO4/H2O2 and HCl/H2O2 treatments) was investigated after PECVD of a-SiNx:H and ALD of Al2O3 capping films. The wet chemically grown SiO2 films were compared to thermally grown SiO2 and the

  11. Mercury Wet Scavenging and Deposition Differences by Precipitation Type.

    Science.gov (United States)

    Kaulfus, Aaron S; Nair, Udaysankar; Holmes, Christopher D; Landing, William M

    2017-03-07

    We analyze the effect of precipitation type on mercury wet deposition using a new database of individual rain events spanning the contiguous United States. Measurements from the Mercury Deposition Network (MDN) containing single rainfall events were identified and classified into six precipitation types. Mercury concentrations in surface precipitation follow a power law of precipitation depth that is modulated by precipitation system morphology. After controlling for precipitation depth, the highest mercury deposition occurs in supercell thunderstorms, with decreasing deposition in disorganized thunderstorms, quasi-linear convective systems (QLCS), extratropical cyclones, light rain, and land-falling tropical cyclones. Convective morphologies (supercells, disorganized, and QLCS) enhance wet deposition by a factor of at least 1.6 relative to nonconvective morphologies. Mercury wet deposition also varies by geographic region and season. After controlling for other factors, we find that mercury wet deposition is greater over high-elevation sites, seasonally during summer, and in convective precipitation.

  12. Trace organic compounds in wet atmospheric deposition: an overview

    Science.gov (United States)

    Steinheimer, T.R.; Johnson, S.M.

    1987-01-01

    An overview of the occurrence of organic compounds in wet atmospheric deposition is given. Multiplicity of sources and problems associated with source identification are discussed. Available literature is reviewed by using citations from Chemical Abstracts and Water Resources Abstracts through June 1985 and includes reports published through December 1984 that summarize current knowledge. Approaches to the chemical determination of organic compounds in precipitation are examined in addition to aspects of sampling protocols. Best methods for sample collection and preparation for instrumental analysis continue to be discussed among various investigators. Automatic wet-deposition-only devices for collection and extraction are preferred. Classes of organic compounds that have been identified in precipitation include a spectrum of compounds with differing properties of acidity or basicity, polarity, and water solubility. Those compounds that have been reported in rainfall, snowfall, and ice include hydrocarbons (both aromatic and nonaromatic), chlorinated derivatives of these hydrocarbons, carbonyl compounds (both acidic and nonacidic), and carboxylic acids and esters. Formic and acetic are the most abundant organic acids present. Cloudwater, fogwater, and mist also have been collected and analyzed for organic composition.

  13. Precipitation chemistry and wet deposition in a remote wet savanna site in West Africa: Djougou (Benin)

    Science.gov (United States)

    Akpo, A. B.; Galy-Lacaux, C.; Laouali, D.; Delon, C.; Liousse, C.; Adon, M.; Gardrat, E.; Mariscal, A.; Darakpa, C.

    2015-08-01

    In the framework of the IDAF (IGAC/DEBITS/AFrica) international program, this study aims to study the chemical composition of precipitation and associated wet deposition at the rural site of Djougou in Benin, representative of a West and Central African wet savanna. Five hundred and thirty rainfall samples were collected at Djougou, Benin, from July 2005 to December 2009 to provide a unique database. The chemical composition of precipitation was analyzed for inorganic (Ca2+, Mg2+, Na+, NH4+, K+, NO3-, Cl-, SO42-) and organic (HCOO-, CH3COO-, C2H5COO-, C2O42-) ions, using ion chromatography. The 530 collected rain events represent a total of 5706.1 mm of rainfall compared to the measured pluviometry 6138.9 mm, indicating that the collection efficiency is about 93%. The order of total annual loading rates for soluble cations is NH4+ > Ca2+ > Mg2+ > K+. For soluble anions the order of loading is carbonates > HCOO- > NO3- > CH3COO- > SO42- > Cl- > C2O42- > C2H5COO-. In the wet savanna of Djougou, 86% of the measured pH values range between 4.7 and 5.7 with a median pH of 5.19, corresponding to a VWM (Volume Weighed Mean) H+ concentration of 6.46 μeq·L-1. This acidity results from a mixture of mineral and organic acids. The annual sea salt contribution was computed for K+, Mg2+, Ca2+ and SO42- and represents 4.2% of K+, 41% of Mg2+, 1.3% of Ca2+, and 7.4% of SO42-. These results show that K+, Ca2+, SO42-, and Mg2+ were mainly of non-marine origin. The marine contribution is estimated at 9%. The results of the chemical composition of rainwater of Djougou indicates that, except for the carbonates, ammonium has the highest VWM concentration (14.3 μeq·L-1) and nitrate concentration is 8.2 μeq·L-1. The distribution of monthly VWM concentration for all ions is computed and shows the highest values during the dry season, comparing to the wet season. Identified nitrogenous compound sources (NOx and NH3) are domestic animals, natural emissions from savanna soils, biomass

  14. Quantitative and simultaneous analysis of the polarity of polycrystalline ZnO seed layers and related nanowires grown by wet chemical deposition

    Science.gov (United States)

    Guillemin, Sophie; Parize, Romain; Carabetta, Joseph; Cantelli, Valentina; Albertini, David; Gautier, Brice; Brémond, Georges; Fong, Dillon D.; Renevier, Hubert; Consonni, Vincent

    2017-03-01

    The polarity in ZnO nanowires is an important issue since it strongly affects surface configuration and reactivity, nucleation and growth, electro-optical properties, and nanoscale-engineering device performances. However, measuring statistically the polarity of ZnO nanowire arrays grown by chemical bath deposition and elucidating its correlation with the polarity of the underneath polycrystalline ZnO seed layer grown by the sol-gel process represents a major difficulty. To address that issue, we combine resonant x-ray diffraction (XRD) at Zn K-edge using synchrotron radiation with piezoelectric force microscopy and polarity-sensitive chemical etching to statistically investigate the polarity of more than 107 nano-objects both on the macroscopic and local microscopic scales, respectively. By using high temperature annealing under an argon atmosphere, it is shown that the compact, highly c-axis oriented ZnO seed layer is more than 92% Zn-polar and that only a few small O-polar ZnO grains with an amount less than 8% are formed. Correlatively, the resulting ZnO nanowires are also found to be Zn-polar, indicating that their polarity is transferred from the c-axis oriented ZnO grains acting as nucleation sites in the seed layer. These findings pave the way for the development of new strategies to form unipolar ZnO nanowire arrays as a requirement for a number of nanoscale-engineering devices like piezoelectric nanogenerators. They also highlight the great advantage of resonant XRD as a macroscopic, non-destructive method to simultaneously and statistically measure the polarity of ZnO nanowire arrays and of the underneath ZnO seed layer.

  15. Wet chemical synthesis of soluble gold nanogaps

    DEFF Research Database (Denmark)

    Jain, Titoo; Tang, Qingxin; Bjørnholm, Thomas

    2014-01-01

    NRs) in aqueous solution. Through controlled end-to-end assembly of the AuNRs into dimers or chains, facilitated via target molecules, they can be used as electrical contacts. In this way, the preparation of AuNR-molecule-AuNR junctions by wet chemical methods may afford a large number of identical devices...... with little variation in the interface between molecule and electrode (AuNR). In this Account, we highlight recent progress in using chemically synthesized AuNRs as building blocks for molecular electronic applications. We outline the general synthesis and properties of AuNRs and describe the aqueous growth...... in the nanogaps lets us spectroscopically characterize the molecules via surface-enhanced Raman scattering. We discuss the incorporation of oligopeptides functionalized with acetylene units having uniquely identifiable vibrational modes. This acetylene moiety allows chemical reactions to be performed in the gaps...

  16. Wet deposition flux of trace elements to the Adirondack region

    International Nuclear Information System (INIS)

    Huang, X.; Keskin, S.S.; Gullu, G.; Olmez, I.

    2001-01-01

    Wet deposition samples from two locations in the Adirondack region of New York were analyzed for trace elemental composition by instrumental neutron activation analysis. Annual fluxes of the measured species were determined by precipitation-weighted and linear-regression methods. Despite several episodes of high deposition fluxes, the cumulative areal wet deposition of trace elements increased fairly linearly (r 2 > 0.9) over the two year sampling period at both sites. This implies that short duration sampling programs may be used to estimate long-term fluxes and cumulative wet deposition impacts. Based on the magnitude of their fluxes, the measured species have been divided into four groups: acidic anions, electroneutral balancing cations, and minor and trace elements of anthropogenic origin. (author)

  17. Episodic response project: Wet deposition at watersheds in three regions of the eastern United States

    International Nuclear Information System (INIS)

    Barchet, W.R.

    1991-11-01

    During the period from August 1988 to June 1990, wet-only sampling of precipitation was carried out at three Episodic Response Project sites and at one supplemental site. The three watershed sites are Moss Lake, Biscuit Brook, and Linn Run. The supplemental site was the MAP3S site at Pennsylvania State University that characterizes the central group of northern Appalachian streams. The site operators adhered by varying degrees to the sample collection protocol based on the daily sampling protocol of the MAP3S Precipitation Chemistry Network. Sulfate and nitrate ion together accounted for more than 80% of total anions (in μEq/L) in the precipitation at all sites. Wet deposition of sulfate at Moss Lake, Biscuit Brook, Penn State, and Linn Run averaged 223, 230, 253, and 402 mg/m 2 /month, respectively, whereas nitrate wet deposition averaged 197, 195, 160, and 233 mg/m 2 /month, respectively. Sulfate deposition was a factor of 2 to 4 higher in summer than in winter. The seasonal pattern for nitrate deposition was weak; the seasonal contrast was less than a factor of 2.5 at all sites. The association between the wet deposition and precipitation chemistry at the MAP3S monitoring site and the average for the study watersheds was dependent on the distance between the site and watershed and the intervening terrain. Precipitation chemistry at the monitoring site is representative of that at the ERP study watersheds in the Adirondack and Catskill regions and in the south-western group of watersheds in the Appalachian region. High spatial variability in precipitation amounts makes this assumption weaker for wet deposition. Chemical input to watersheds from dry deposition has not been determined at any site but could range from a factor of 0.3 to 1.0 of the wet deposition. 7 refs., 38 figs., 12 tabs

  18. Atmospheric wet deposition of mercury in North America

    Energy Technology Data Exchange (ETDEWEB)

    Sweet, C.W.; Prestbo, E.; Brunette, B.

    1999-07-01

    Currently, 39 states in the US and 5 Canadian provinces have issued advisories about the dangers of eating mercury-contaminated fish taken from waters within their boundaries. The problem is most severe in the Great Lakes region, the Northeast US states, the Canadian maritime provinces, and in south Florida where many lakes and streams contain fish with concentrations of 1 ppm or higher. For many rural and remote locations, atmospheric deposition is the primary source of mercury. In 1995, the National Atmospheric Deposition Program (NADP) initiated a program to monitor total mercury and methylmercury (MMHg) in wet deposition (rain and snow) in North America. In this program, the Mercury Deposition Network (MDN), individual monitoring sites are funded and operated by a variety of local, state, and federal agencies. However, sampling and analysis are coordinated through a central laboratory so that all of the samples are collected and analyzed using the same protocols. Weekly wet-only precipitation samples are collected using an all-glass sampling train and special handling techniques. Analysis is by cold vapor atomic fluorescence spectrometry using USEPA Method 1631 for total mercury. Nearly 40 MDN sites are in operation in 1999. Most of the sites are in the eastern US and Canada. During 1996 and 1997, the volume-weighted mean concentration of total mercury in precipitation collected at 22 sites ranged from 6.0 to 18.9 ng/L. Annual deposition varied between 2.1 and 25.3 {micro} g/m{sup 2}. The average weekly wet deposition of total mercury is more than three times higher in the summer (June-August) than in the winter (December-February). This increase is due to both higher amounts of precipitation and higher concentrations of mercury in precipitation during the summer. The highest values for mercury concentration in precipitation and wet deposition of mercury were measured in the southeastern US.

  19. Wet chemical etching of Al-doped ZnO film deposited by RF magnetron sputtering method on textured glass substrate for energy application

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Ki Hwan; Nam, Sang Hun; Jung, Won Suk; Lee, Yong Min; Yang, Hee Su; Boo, Jin Hyo [Dept. of Chemistry, Sungkyunkwan University, Suwon (Korea, Republic of)

    2015-03-15

    The etching of glasses in aqueous hydrofluoric acid (HF) solutions is applied in many technological fields. Particularly, the textured transparent conductive oxide materials on the glass substrate etched by HF were used to improve the current density of solar cells. In this study, the textured glass substrate has been etched by solution and the Al-doped ZnO (AZO) thin films have been prepared on this textured glass substrates by RF magnetron sputtering method. After the AZO film deposition, the surface of AZO has been etched by hydrochloric acid with different concentration and etching time. Etched AZO thin films had higher haze ratio and sheet resistance than bare AZO glass. Increases in the root-mean-square surface roughness of AZO films enhanced from 53.78 to 84.46 nm the haze ratio in above 700 nm wavelength. Our process could be applicable in texturing glass and etching AZO surface to fabricate solar cell in industrial scale. We also carried out fabricating an organic solar-cell device. Energy conversion efficiency improvement of 123% was obtained with textured AZO-based solar-cell device compared with that of nontextured solar-cell device.

  20. Wet-Chemical Surface Texturing of Sputter-Deposited ZnO:Al Films as Front Electrode for Thin-Film Silicon Solar Cells

    Directory of Open Access Journals (Sweden)

    Xia Yan

    2015-01-01

    Full Text Available Transparent conductive oxides (TCOs play a major role as the front electrodes of thin-film silicon (Si solar cells, as they can provide optical scattering and hence improved photon absorption inside the devices. In this paper we report on the surface texturing of aluminium-doped zinc oxide (ZnO:Al or AZO films for improved light trapping in thin-film Si solar cells. The AZO films are deposited onto soda-lime glass sheets via pulsed DC magnetron sputtering. Several promising AZO texturing methods are investigated using diluted hydrochloric (HCl and hydrofluoric acid (HF, through a two-step etching process. The developed texturing procedure combines the advantages of the HCl-induced craters and the smaller and jagged—but laterally more uniform—features created by HF etching. In the two-step process, the second etching step further enhances the optical haze, while simultaneously improving the uniformity of the texture features created by the HCl etch. The resulting AZO films show large haze values of above 40%, good scattering into large angles, and a surface angle distribution that is centred at around 30°, which is known from the literature to provide efficient light trapping for thin-film Si solar cells.

  1. Meteorological testing and analysis of sampling equipment for wet deposition

    International Nuclear Information System (INIS)

    Winkler, P.; Jobst, S.; Harder, C.

    1989-01-01

    11 rain collector types for wet deposition were subjected to a field test. Two of the nine types were identically constructed. The following measured values were analyzed: amount of rainfall, electrical conductivity, pH value, Cl - , NO 3 - , SO 4 = , NH 4 + , Na + , K + , Ca ++ , Mg ++ , Fe, Pb, Cu, Cd. The analysis was restricted to rainfall. In a basic study structural and statistical analyses of precipitations were made in order to find out from which extent of intensity resp. rain volume per rainfall the precipitations are important for wet deposition. Some sensors required intensities of nearly 1 mm/h in order to recognize all rainfalls. In order to reach a better standardization of the measuring technique the funnel geometry should be standardized. The current technique is not suited for correctly registering the deposition which is connected with light and very light rainfall. It was found out in rinsing tests with diluted HNO 3 that considerable amounts of trace metals accumulate at funnel walls and in headers, although the collecting device had been subjected to a thorough acid purification before. For the determination of the wet deposition of the trace metals problems arise if the samples are filtered and the filters are not analyzed. In that case particle-bound metals which are suspended in raindrops will not be registered. After comparing the equipment some of the devices were improved in order to eliminate known sources of contamination. (orig./KW) [de

  2. Wet deposition of poly- and perfluorinated compounds in Northern Germany

    International Nuclear Information System (INIS)

    Dreyer, Annekatrin; Matthias, Volker; Weinberg, Ingo; Ebinghaus, Ralf

    2010-01-01

    Twenty precipitation samples were taken concurrently with air samples at a northern German monitoring site over a period of 7 months in 2007 and 2008. Thirty four poly- and perfluorinated compounds (PFC) were determined in rain water samples by solid phase extraction and HPLC-MS/MS analysis. Seventeen compounds were detected in rain water with ΣPFC concentrations ranging from 1.6 ng L -1 to 48.6 ng L -1 . Perfluorooctanoate (PFOA) and perfluorobutanate (PFBA) were the compounds that were usually observed in highest concentrations. Calculated ΣPFC deposition rates were between 2 and 91 ng m -2 d -1 . These findings indicate that particle phase PFC are deposited from the atmosphere by precipitation. A relationship between PFC wet deposition and air concentration may be established via precipitation amounts. Trajectory analysis revealed that PFC concentration and deposition estimates in precipitation can only be explained if a detailed air mass history is considered. - Information on air mass history, meteorological conditions, and distribution of PFC sources is necessary to understand and estimate PFC concentrations and wet deposition.

  3. 1988 Wet deposition temporal and spatial patterns in North America

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, J.C.; Olsen, A.R.; Bittner, E.A.

    1992-03-01

    The focus of this report is on North American wet deposition temporal patterns from 1979 to 1988 and spatial patterns for 1988. It is the third in a series of reports that investigate the patterns of annual precipitation-weighted average concentration and annual deposition for nine ion species: hydrogen, sulfate, nitrate, ammonium, calcium, chloride, sodium, potassium, and magnesium. Mosaic maps, based on surface estimation using kriging, display concentration and deposition spatial patterns of pH, hydrogen, sulfate, nitrate, ammonium, and calcium ion species for 1988 annual, winter, and summer periods. Temporal pattern analyses use a subset of 35 sites over a 10-year (1979--1988) period and an expanded subset of 137 sites, with greater spatial coverage, over a 7-year (1982--1988) period. The 10-year period represents the longest period with wet deposition monitoring data available that has a sufficient number of sites with data of known quality to allow a descriptive summary of annual temporal patterns. Sen's median trend estimate and Kendall's seasonal tau (KST) test are calculated for each ion species concentration and deposition at each site in both subsets.

  4. 1988 Wet deposition temporal and spatial patterns in North America

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, J.C.; Olsen, A.R.; Bittner, E.A.

    1992-03-01

    The focus of this report is on North American wet deposition temporal patterns from 1979 to 1988 and spatial patterns for 1988. It is the third in a series of reports that investigate the patterns of annual precipitation-weighted average concentration and annual deposition for nine ion species: hydrogen, sulfate, nitrate, ammonium, calcium, chloride, sodium, potassium, and magnesium. Mosaic maps, based on surface estimation using kriging, display concentration and deposition spatial patterns of pH, hydrogen, sulfate, nitrate, ammonium, and calcium ion species for 1988 annual, winter, and summer periods. Temporal pattern analyses use a subset of 35 sites over a 10-year (1979--1988) period and an expanded subset of 137 sites, with greater spatial coverage, over a 7-year (1982--1988) period. The 10-year period represents the longest period with wet deposition monitoring data available that has a sufficient number of sites with data of known quality to allow a descriptive summary of annual temporal patterns. Sen`s median trend estimate and Kendall`s seasonal tau (KST) test are calculated for each ion species concentration and deposition at each site in both subsets.

  5. Chemical solution deposition techniques for epitaxial growth of complex oxides

    NARCIS (Netherlands)

    ten Elshof, Johan E.; Koster, G.; Huijben, Mark; Rijnders, G.

    2015-01-01

    The chemical solution deposition (CSD) process is a wet-chemical process that is employed to fabricate a wide variety of amorphous and crystalline oxide thin films. This chapter describes the typical steps in a CSD process and their influence on the final microstructure and properties of films, and

  6. 1987 wet deposition temporal and spatial patterns in North America

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, J.C.; Olsen, A.R.

    1990-03-01

    The focus of this report is on North American wet deposition temporal patterns from 1979 to 1987 and spatial patterns for 1987. The report investigates the patterns of annual precipitation-weighted average concentration and annual deposition for nine ion species: hydrogen, sulfate, nitrate, ammonium, calcium, chloride, sodium, potassium, and magnesium. Data are from the Acid Deposition System (ADS) for the statistical reporting of North American deposition data which includes the National Atmospheric Deposition Program/National Trends Network (NADP/NTN), the MAP3S precipitation chemistry network, the Utility Acid Precipitation Study Program (UAPSP), the Canadian Precipitation Monitoring Network (CAPMoN), and the daily and 4-weekly Acidic Precipitation in Ontario Study (APIOS-D and APIOS-C). Mosaic maps, based on surface estimation using kriging, display concentration and deposition spatial patterns of pH, hydrogen, sulfate, nitrate, ammonium, and calcium ion species for 1987 annual, winter, and summer periods. The temporal pattern analyses use a subset of 39 sites over a 9-year (1979--1987) period and an expanded subset of 140 sites with greater spatial coverage over a 6-year (1982--1987) period. 68 refs., 15 figs., 15 tabs.

  7. Wet-etch sequence optimisation incorporating time dependent chemical maintenance

    NARCIS (Netherlands)

    Kruif, B.J. de

    2015-01-01

    Wafer fabrication is the major cost contributor in semiconductor manufacturing. One of the steps in the fabrication is the removal of exposed layers in an automatic wet-etch station with chemicals. In time, these chemicals get polluted and their effectiveness decreases. Therefore, the chemicals in

  8. Indium sulfide buffer layers deposited by dry and wet methods

    International Nuclear Information System (INIS)

    Asenjo, B.; Sanz, C.; Guillen, C.; Chaparro, A.M.; Gutierrez, M.T.; Herrero, J.

    2007-01-01

    Indium sulfide (In 2 S 3 ) thin films have been deposited on amorphous glass, glass coated by tin oxide (TCO) and crystalline silicon substrates by two different methods: modulated flux deposition (MFD) and chemical bath deposition (CBD). Composition, morphology and optical characterization have been carried out with Scanning Electron Microscopy (SEM), IR-visible-UV Spectrophotometry, X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectrometer. Different properties of the films have been obtained depending on the preparation techniques. With MFD, In 2 S 3 films present more compact and homogeneous surface than with CBD. Films deposited by CBD present also indium oxide in their composition and higher absorption edge values when deposited on glass

  9. Characterization of silver nanoparticles prepared by wet chemical ...

    African Journals Online (AJOL)

    Results: The silver nanoparticles formed were spherical in shape with mean size of 10.3 nm. The ... antibacterial activity against various strains of bacteria. Keywords: Wet ..... Fang J, Zhong C, Mu R. The study of deposited silver particulate ...

  10. Dependence of wet etch rate on deposition, annealing conditions and etchants for PECVD silicon nitride film

    International Nuclear Information System (INIS)

    Tang Longjuan; Zhu Yinfang; Yang Jinling; Li Yan; Zhou Wei; Xie Jing; Liu Yunfei; Yang Fuhua

    2009-01-01

    The influence of deposition, annealing conditions, and etchants on the wet etch rate of plasma enhanced chemical vapor deposition (PECVD) silicon nitride thin film is studied. The deposition source gas flow rate and annealing temperature were varied to decrease the etch rate of SiN x :H by HF solution. A low etch rate was achieved by increasing the SiH 4 gas flow rate or annealing temperature, or decreasing the NH 3 and N2 gas flow rate. Concentrated, buffered, and dilute hydrofluoric acid were utilized as etchants for SiO 2 and SiN x :H. A high etching selectivity of SiO 2 over SiN x :H was obtained using highly concentrated buffered HF.

  11. Urban wet deposition nitrate: a comparison to non-urban deposition

    International Nuclear Information System (INIS)

    Schultz, J.A.M.

    1994-01-01

    The concentration of nitrate in both wet and dry deposition has both increased historically and currently, and recently parallels emissions in NO x . Since NO x is produced in amounts comparable to SO 2 , it is an important contributor to acid deposition, and is produced in higher amounts in urban areas due to concentrated sources. Prior to to this study, national acid deposition monitoring networks in the United States have been and remain established in non-urban areas. This research study consisted of a comparison of precipitation sampling and analysis of wet deposition nitrate and pH for each deposition event in each of two urban sites over a 15 mo period. Also, a comparison of urban data and data generated at a nearby non-urban NADP site was made by examination of both monthly and seasonal data. This research suggests that national monitoring programs should consider inclusion of urban and non-urban monitoring sites in order to achieve a more representative regional assessment. 24 refs., 2 figs., 2 tabs

  12. Temperature-dependent evolution of the wetting layer thickness during Ge deposition on Si(001).

    Science.gov (United States)

    Bergamaschini, R; Brehm, M; Grydlik, M; Fromherz, T; Bauer, G; Montalenti, F

    2011-07-15

    The evolution of the wetting layer (WL) thickness during Ge deposition on Si(001) is analyzed with the help of a rate-equation approach. The combined role of thickness, island volume and shape-dependent chemical potentials is considered. Several experimental observations, such as WL thinning following the pyramid-to-dome transformation, are captured by the model, as directly demonstrated by a close comparison with photoluminescence measurements (PL) on samples grown at three different temperatures. The limitations of the model in describing late stages of growth are critically addressed.

  13. Simulation of convection-driven wet-chemical etching

    NARCIS (Netherlands)

    Driesen, C.H.

    1999-01-01

    In a wet-chemical etching process, the resulting etched shape is smaller than the originally designed shape at the mask. This is caused by the fact that, as soon as material next to the mask is dissolved, material under the mask will be dissolved too. This is the so-called undercut effect. During an

  14. Simulation of convection-driven wet-chemical etching

    NARCIS (Netherlands)

    Driesen, C.H.

    1999-01-01

    a wet-chemical etching process, the resulting etched shape is smaller than the originally designed shape at the mask. This is caused by the fact that, as soon as material next to the mask is dissolved, material under the mask will be dissolved too. This is the so-called undercut effect. During an

  15. Physical chemistry of wet chemical anisotropic etching of silicon

    NARCIS (Netherlands)

    Elwenspoek, Michael Curt

    1995-01-01

    In this paper we explain a view to understand the anisotropy of the etching of silicon in certain wet chemical agents (such as KOH). The starting point is the assumption that the [Left angle bracket]111[Right Angle Bracket] face of silicon is a flat face, the etch rate of which is then governed by a

  16. Increasing aeolian dust deposition to snowpacks in the Rocky Mountains inferred from snowpack, wet deposition, and aerosol chemistry

    Science.gov (United States)

    Clow, David W.; Williams, Mark W.; Schuster, Paul F.

    2016-01-01

    Mountain snowpacks are a vital natural resource for ∼1.5 billion people in the northern Hemisphere, helping to meet human and ecological demand for water in excess of that provided by summer rain. Springtime warming and aeolian dust deposition accelerate snowmelt, increasing the risk of water shortages during late summer, when demand is greatest. While climate networks provide data that can be used to evaluate the effect of warming on snowpack resources, there are no established regional networks for monitoring aeolian dust deposition to snow. In this study, we test the hypothesis that chemistry of snow, wet deposition, and aerosols can be used as a surrogate for dust deposition to snow. We then analyze spatial patterns and temporal trends in inferred springtime dust deposition to snow across the Rocky Mountains, USA, for 1993–2014. Geochemical evidence, including strong correlations (r2 ≥ 0.94) between Ca2+, alkalinity, and dust concentrations in snow deposited during dust events, indicate that carbonate minerals in dust impart a strong chemical signature that can be used to track dust deposition to snow. Spatial patterns in chemistry of snow, wet deposition, and aerosols indicate that dust deposition increases from north to south in the Rocky Mountains, and temporal trends indicate that winter/spring dust deposition increased by 81% in the southern Rockies during 1993–2014. Using a multivariate modeling approach, we determined that increases in dust deposition and decreases in springtime snowfall combined to accelerate snowmelt timing in the southern Rockies by approximately 7–18 days between 1993 and 2014. Previous studies have shown that aeolian dust emissions may have doubled globally during the 20th century, possibly due to drought and land-use change. Climate projections for increased aridity in the southwestern U.S., northern Africa, and other mid-latitude regions of the northern Hemisphere suggest that aeolian dust emissions may continue to

  17. Solid state de-wetting observed for vapor deposited copper films on carbon substrates

    International Nuclear Information System (INIS)

    Schrank, C.; Eisenmenger-Sittner, C.; Neubauer, E.; Bangert, H.; Bergauer, A.

    2004-01-01

    Copper-Carbon composites are a good example for novel materials consisting of components with extremely different physical and chemical properties. They have a high potential for an application as heat sinks for electronic components, but the joining of the two materials is a difficult task. To obtain reasonable mechanical and thermal contact between copper and carbon the following route was chosen. First glassy-carbon substrates were subjected to an RF-Nitrogen plasma treatment. Then 300 nm thick copper coatings were sputter-deposited on the plasma treated surface within the same vacuum chamber. Finally, the samples were removed from the deposition chamber and either investigated immediately or thermally annealed at 850 deg. C under high vacuum conditions (10 -4 Pa). While non-annealed copper-coatings were continuous and showed excellent adhesion values of approximately 700 N/cm 2 , the heat treated samples lose their continuity by a de-wetting process. At the beginning holes are formed, then a labyrinth-like morphology develops and finally the coating consists of isolated droplets. All these processes occur well below the melting temperature of copper and were observed by AFM and SEM. The mechanism of this solid-state de-wetting process is investigated in relation to the recent literature on de-wetting and its consequences on the manufacturing of copper-carbon composites are discussed

  18. Origin and chemical composition of evaporite deposits

    Science.gov (United States)

    Moore, George William

    1960-01-01

    A comparative study of marine evaporite deposits forming at the present time along the pacific coast of central Mexico and evaporite formations of Permian age in West Texas Basin was made in order to determine if the modern sediments provide a basis for understanding environmental conditions that existed during deposition of the older deposits. The field work was supplemented by investigations of artificial evaporite minerals precipitated in the laboratory and by study of the chemical composition of halite rock of different geologic ages. The environment of deposition of contemporaneous marine salt deposits in Mexico is acidic, is strongly reducing a few centimeters below the surface, and teems with microscopic life. Deposition of salt, unlike that of many other sediments, is not wholly a constructional phenomenon. Permanent deposits result only if a favorable balance exists between deposition in the dry season and dissolution in the wet season. Evaporite formations chosen for special study in the West Texas Basin are, in ascending order, the Castile, Salado, and Rustler formations, which have a combined thickness of 1200 meters. The Castile formation is largely composed of gypsum rock, the Salado, halite rock, and the Rustler, quartz and carbonate sandstone. The lower part of the Castile formation is bituminous and contains limestone laminae. The Castile and Rustler formations thicken to the south at the expense of salt of the intervening Salado formation. The clastic rocks of the Rustler formation are interpreted as the deposits of a series of barrier islands north of which halite rock of the Salado was deposited. The salt is believed to have formed in shallow water of uniform density that was mixed by the wind. Where water depth exceeded the depth of the wind mixing, density stratification developed, and gypsum was deposited. Dense water of high salinity below the density discontinuity was overlain by less dense, more normally saline water which was derived from

  19. Calcium phosphate bioceramics prepared from wet chemically precipitated powders

    Directory of Open Access Journals (Sweden)

    Kristine Salma

    2010-03-01

    Full Text Available In this work calcium phosphates were synthesized by modified wet chemical precipitation route. Contrary to the conventional chemical precipitation route calcium hydroxide was homogenized with planetary mill. Milling calcium oxide and water in planetary ball mill as a first step of synthesis provides a highly dispersed calcium hydroxide suspension. The aim of this work was to study the influence of main processing parameters of wet chemical precipitation synthesis product and to control the morphology, phase and functional group composition and, consequently, thermal stability and microstructure of calcium phosphate bioceramics after thermal treatment. The results showed that it is possible to obtain calcium phosphates with different and reproducible phase compositions after thermal processing (hydroxyapatite [HAp], β-tricalcium phosphate [β-TCP] and HAp/β-TCP by modified wet-chemical precipitation route. The β-TCP phase content in sintered bioceramics samples is found to be highly dependent on the changes in technological parameters and it can be controlled with ending pH, synthesis temperature and thermal treatment. Pure, crystalline and highly thermally stable (up to 1300°C HAp bioceramics with homogenous grainy microstructure, grain size up to 200–250 nm and high open porosity can be successfully obtained by powder synthesized at elevated synthesis temperature of 70°C and stabilizing ending pH at 9.

  20. Wet and dry atmospheric deposition on TiO2 coated glass

    International Nuclear Information System (INIS)

    Chabas, Anne; Gentaz, Lucile; Lombardo, Tiziana; Sinegre, Romain; Falcone, Roberto; Verita, Marco; Cachier, Helene

    2010-01-01

    To prevent the soiling of glass window used in the built environment, the use TiO 2 coated products appears an important application matter. To test the cleaning efficiency and the sustainability of self-cleaning glass, a field experiment was conducted under real life condition, on a site representative of the background urban pollution. Samples of float glass, used as reference, and commercialized TiO 2 coated glasses were exposed to dry and wet atmospheric deposition during two years. The crossed optical, chemical and microscopic evaluations performed, after withdrawal, allowed highlighting a sensible difference between the reference and the self-cleaning substrate in terms of accumulation, nature, abundance and geometry of the deposit. This experiment conducted in real site emphasized on the efficacy of self-cleaning glass to reduce the maintenance cost. - This paper evaluates the self-cleaning glass efficiency highlighting its ability to prevent soiling and to be used as a mean of remediation.

  1. 3D Modelling of Transport, Deposition and Resuspension of Highway Deposited Sediments in wet Detention Ponds

    DEFF Research Database (Denmark)

    Bentzen, Thomas Ruby

    2010-01-01

    concrete channel with width of 0.8m and a water depth of approximately 0.8m and in circular flume experiments in order to reproduce near-bed specific processes such as resuspension and consolidation. With a fairly good agreement with measurements, modelling of hydrodynamics, transport of dissolved...... pollutants and particles in wet detention ponds is possible with application of a three dimensional RANS model and the advection/dispersion equation taken physical phenomena like wind, waves, deposition, erosion and consolidation of the bottom sediment into account....

  2. Wet-chemical passivation of atomically flat and structured silicon substrates for solar cell application

    Science.gov (United States)

    Angermann, H.; Rappich, J.; Korte, L.; Sieber, I.; Conrad, E.; Schmidt, M.; Hübener, K.; Polte, J.; Hauschild, J.

    2008-04-01

    Special sequences of wet-chemical oxidation and etching steps were optimised with respect to the etching behaviour of differently oriented silicon to prepare very smooth silicon interfaces with excellent electronic properties on mono- and poly-crystalline substrates. Surface photovoltage (SPV) and photoluminescence (PL) measurements, atomic force microscopy (AFM) and scanning electron microscopy (SEM) investigations were utilised to develop wet-chemical smoothing procedures for atomically flat and structured surfaces, respectively. Hydrogen-termination as well as passivation by wet-chemical oxides were used to inhibit surface contamination and native oxidation during the technological processing. Compared to conventional pre-treatments, significantly lower micro-roughness and densities of surface states were achieved on mono-crystalline Si(100), on evenly distributed atomic steps, such as on vicinal Si(111), on silicon wafers with randomly distributed upside pyramids, and on poly-crystalline EFG ( Edge-defined Film-fed- Growth) silicon substrates. The recombination loss at a-Si:H/c-Si interfaces prepared on c-Si substrates with randomly distributed upside pyramids was markedly reduced by an optimised wet-chemical smoothing procedure, as determined by PL measurements. For amorphous-crystalline hetero-junction solar cells (ZnO/a-Si:H(n)/c-Si(p)/Al) with textured c-Si substrates the smoothening procedure results in a significant increase of short circuit current Isc, fill factor and efficiency η. The scatter in the cell parameters for measurements on different cells is much narrower, as compared to conventional pre-treatments, indicating more well-defined and reproducible surface conditions prior to a-Si:H emitter deposition and/or a higher stability of the c-Si surface against variations in the a-Si:H deposition conditions.

  3. Wet deposition at the base of Mt Everest: Seasonal evolution of the chemistry and isotopic composition

    Science.gov (United States)

    Balestrini, Raffaella; Delconte, Carlo A.; Sacchi, Elisa; Wilson, Alana M.; Williams, Mark W.; Cristofanelli, Paolo; Putero, Davide

    2016-12-01

    The chemistry of wet deposition was investigated during 2012-2014 at the Pyramid International Laboratory in the Upper Khumbu Valley, Nepal, at 5050 m a.s.l., within the Global Atmosphere Watch (GAW) programme. The main hydro-chemical species and stable isotopes of the water molecule were determined for monsoon rain (July-September) and snow samples (October-June). To evaluate the synoptic-scale variability of air masses reaching the measurement site, 5 day back-trajectories were computed for the sampling period. Ion concentrations in precipitation during the monsoon were low suggesting that they represent global regional background concentrations. The associations between ions suggested that the principal sources of chemical species were marine aerosols, rock and soil dust, and fossil fuel combustion. Most chemical species exhibited a pattern during the monsoon, with maxima at the beginning and at the end of the season, partially correlated with the precipitation amount. Snow samples exhibited significantly higher concentrations of chemical species, compared to the monsoon rainfall observations. Particularly during 2013, elevated concentrations of NO3-, SO42- and NH4+ were measured in the first winter snow event, and in May at the end of the pre-monsoon season. The analysis of large-scale circulation and wind regimes as well as atmospheric composition observations in the region indicates the transport of polluted air masses from the Himalayan foothills and Indian sub-continent up to the Himalaya region. During the summer monsoon onset period, the greater values of pollutants can be attributed to air-mass transport from the planetary boundary layer (PBL) of the Indo-Gangetic plains. Isotopic data confirm that during the monsoon period, precipitation occurred from water vapor that originated from the Indian Ocean and the Bay of Bengal; by contrast during the non-monsoon period, an isotopic signature of more continental origin appeared, indicating that the higher

  4. Comparison of annual dry and wet deposition fluxes of selected pesticides in Strasbourg, France

    International Nuclear Information System (INIS)

    Sauret, Nathalie; Wortham, Henri; Strekowski, Rafal; Herckes, Pierre; Nieto, Laura Ines

    2009-01-01

    This work summarizes the results of a study of atmospheric wet and dry deposition fluxes of Deisopropyl-atrazine (DEA), Desethyl-atrazine (DET), Atrazine, Terbuthylazine, Alachlor, Metolachlor, Diflufenican, Fenoxaprop-p-ethyl, Iprodione, Isoproturon and Cymoxanil pesticides conducted in Strasbourg, France, from August 2000 through August 2001. The primary objective of this work was to calculate the total atmospheric pesticide deposition fluxes induced by atmospheric particles. To do this, a modified one-dimensional cloud water deposition model was used. All precipitation and deposition samples were collected at an urban forested park environment setting away from any direct point pesticide sources. The obtained deposition fluxes induced by atmospheric particles over a forested area showed that the dry deposition flux strongly contributes to the total deposition flux. The dry particle deposition fluxes are shown to contribute from 4% (DET) to 60% (cymoxanil) to the total deposition flux (wet + dry). - A modified one-dimensional cloud water deposition model is used to estimate the deposition fluxes of pesticides in the particle phase and compare the relative importance of dry and wet depositions

  5. Comparison of annual dry and wet deposition fluxes of selected pesticides in Strasbourg, France

    Energy Technology Data Exchange (ETDEWEB)

    Sauret, Nathalie [Marseilles University, Laboratoire Chimie Provence - UMR 6264, Campus Saint Charles, Case 29, 3 Place Victor Hugo, 13331 Marseilles Cedex 03 (France); Wortham, Henri [Marseilles University, Laboratoire Chimie Provence - UMR 6264, Campus Saint Charles, Case 29, 3 Place Victor Hugo, 13331 Marseilles Cedex 03 (France)], E-mail: Henri.Wortham@univ-provence.fr; Strekowski, Rafal [Marseilles University, Laboratoire Chimie Provence - UMR 6264, Campus Saint Charles, Case 29, 3 Place Victor Hugo, 13331 Marseilles Cedex 03 (France); Herckes, Pierre [Arizona State University, Department of Chemistry and Biochemistry, Tempe, AZ 85287-1604 (United States); Nieto, Laura Ines [Marseilles University, Laboratoire Chimie Provence - UMR 6264, Campus Saint Charles, Case 29, 3 Place Victor Hugo, 13331 Marseilles Cedex 03 (France)

    2009-01-15

    This work summarizes the results of a study of atmospheric wet and dry deposition fluxes of Deisopropyl-atrazine (DEA), Desethyl-atrazine (DET), Atrazine, Terbuthylazine, Alachlor, Metolachlor, Diflufenican, Fenoxaprop-p-ethyl, Iprodione, Isoproturon and Cymoxanil pesticides conducted in Strasbourg, France, from August 2000 through August 2001. The primary objective of this work was to calculate the total atmospheric pesticide deposition fluxes induced by atmospheric particles. To do this, a modified one-dimensional cloud water deposition model was used. All precipitation and deposition samples were collected at an urban forested park environment setting away from any direct point pesticide sources. The obtained deposition fluxes induced by atmospheric particles over a forested area showed that the dry deposition flux strongly contributes to the total deposition flux. The dry particle deposition fluxes are shown to contribute from 4% (DET) to 60% (cymoxanil) to the total deposition flux (wet + dry). - A modified one-dimensional cloud water deposition model is used to estimate the deposition fluxes of pesticides in the particle phase and compare the relative importance of dry and wet depositions.

  6. Mechanism of deposit formation on fuel-wetted metal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Stavinoha, L.L.; Westbrook, S.R.; McInnis, L.A. [Southwest Research Institute, San Antonio, TX (United States)

    1995-05-01

    Experiments were performed in a Single-Tube Heat Exchanger (STHE) apparatus and a Hot Liquid Process Simulator (HLPS) configured and operated to meet Jet Fuel Thermal Oxidation Tester (JFTOT) ASTM D 3241 requirements. The HLPS-JFTOT heater tubes used were 1018 mild steel, 316 stainless steel (SS), 304 stainless steel (SS), and 304 SS tubes coated with aluminum, magnesium, gold, and copper. A low-sulfur Jet A fuel with a breakpoint temperature of 254{degrees}C was used to create deposits on the heater tubes at temperatures of 300{degrees}C, 340{degrees}C, and 380{degrees}C. Deposit thickness was measured by dielectric breakdown voltage and Auger ion milling. Pronounced differences between the deposit thickness measuring techniques suggested that both the Auger milling rate and the dielectric strength of the deposit may be affected by deposit morphology/composition (such as metal ions that may have become included in the bulk of the deposit). Carbon burnoff data were obtained as a means of judging the validity of DMD-derived deposit evaluations. ESCA data suggest that the thinnest deposit was on the magnesium-coated test tube. The Scanning Electron Microscope (SEM) photographs showed marked variations in the deposit morphology and the results suggested that surface composition has a significant effect on the mechanism of deposition. The most dramatic effect observed was that the bulk of deposits moved to tube locations of lower temperature as the maximum temperature of the tube was increased from 300{degrees} to 380{degrees}C, also verified in a single-tube heat exchanger. The results indicate that the deposition rate and quantity at elevated temperatures is not completely temperature dependent, but is limited by the concentration of dissolved oxygen and/or reactive components in the fuel over a temperature range.

  7. Organic micropollutants in wet and dry depositions in the Venice Lagoon.

    Science.gov (United States)

    Gambaro, Andrea; Radaelli, Marta; Piazza, Rossano; Stortini, Angela Maria; Contini, Daniele; Belosi, Franco; Zangrando, Roberta; Cescon, Paolo

    2009-08-01

    Atmospheric transport is an important route by which pollutants are conveyed from the continents to both coastal and open sea. The role of aerosol deposition in the transport of polycyclic aromatic hydrocarbons (PAHs), polychlorobiphenyls (PCBs) and polybromodiphenyls ethers (PBDEs) to water and soil systems has been evaluated by measuring their concentrations in wet and dry depositions to the Venice Lagoon. The organic micropollutant flux data indicate that they contribute to the total deposition flux in different ways through wet and dry deposition, showing that the prevalent contribution derives from wet deposition. The fluxes calculated for PBDEs, showed the prevalence of 47, 99, 100 and 183 congeners, both in dry and wet fluxes. With regard to PCBs, the flux of summation operatorPCB for wet deposition is in the same order of magnitude of the diffusive flux at the air-water interface. The PAH fluxes obtained in the present study are similar to those obtained in previous studies on the atmospheric bulk deposition to the Venice Lagoon. The ratios between Phe/Ant and Fl/Py indicate that the pollutants sources are pyrolytic, deriving from combustion fuels.

  8. Thermal plasma chemical vapor deposition

    International Nuclear Information System (INIS)

    Heberlein, J.; Pfender, E.

    1993-01-01

    Thermal plasmas, with temperatures up to and even exceeding 10 4 K, are capable of producing high density vapor phase precursors for the deposition of relatively thick films. Although this technology is still in its infancy, it will fill the void between the relatively slow deposition processes such as physical vapor deposition and the high rate thermal spray deposition processes. In this chapter, the present state-of-the-art of this field is reviewed with emphasis on the various types of reactors proposed for this emerging technology. Only applications which attracted particular attention, namely diamond and high T c superconducting film deposition, are discussed in greater detail. (orig.)

  9. Lecithin-based wet chemical precipitation of hydroxyapatite nanoparticles.

    Science.gov (United States)

    Michał, Wojasiński; Ewa, Duszyńska; Tomasz, Ciach

    Hydroxyapatite Ca 10 (PO 4 ) 6 (OH) 2 nanoparticles have been successfully synthesized by the wet chemical precipitation method at 60 °C in the presence of biocompatible natural surfactant-lecithin. The composition and morphology of nanoparticles of hydroxyapatite synthesized with lecithin (nHAp-PC) was studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Size distribution for nanoparticles was measured by nanoparticle tracking analysis in NanoSight system. We discuss in details influence of lecithin concentration in reaction system on nHAp-PC morphology, as well as on size distributions and suspendability of nanoparticles. Product exhibits crystalline structure and chemical composition of hydroxyapatite, with visible traces of lecithin. Difference in surfactant amounts results in changes in particles morphology and their average size.

  10. Electrophoretic deposition of titania nanoparticles: Wet density of ...

    Indian Academy of Sciences (India)

    Administrator

    field has a dual effect on the packing density of particles in the deposits formed by .... Saturated calomel electrode (SCE) and a platinum wire mesh were used as .... density of the deposit, the smaller the volume of liquid phase, which should be.

  11. Removal of Atmospheric Ethanol by Wet Deposition: A Global Flux Estimate

    Science.gov (United States)

    Felix, J. D. D.; Willey, J. D.; Avery, B.; Thomas, R.; Mullaugh, K.; Kieber, R. J.; Mead, R. N.; Helms, J. R.; Campos, L.; Shimizu, M. S.; Guibbina, F.

    2017-12-01

    Global ethanol fuel consumption has increased exponentially over the last two decades and the US plans to double annual renewable fuel production in the next five years as required by the renewable fuel standard. Regardless of the technology or feedstock used to produce the renewable fuel, the primary end product will be ethanol. Increasing ethanol fuel consumption will have an impact on the oxidizing capacity of the atmosphere and increase atmospheric concentrations of the secondary pollutant peroxyacetyl nitrate as well a variety of VOCs with relatively high ozone reactivities (e.g. ethanol, formaldehyde, acetaldehyde). Despite these documented effects of ethanol emissions on atmospheric chemistry, current global atmospheric ethanol budget models have large uncertainties in the magnitude of ethanol sources and sinks. The presented work investigates the global wet deposition sink by providing the first estimate of the global wet deposition flux of ethanol (2.4 ± 1.6 Tg/yr) based on empirical wet deposition data (219 samples collected at 12 locations). This suggests the wet deposition sink removes between 6 and 17% of atmospheric ethanol annually. Concentrations of ethanol in marine wet deposition (25 ± 6 nM) were an order of magnitude less than in the majority of terrestrial deposition (345 ± 280 nM). Terrestrial deposition collected in locations impacted by high local sources of biofuel usage and locations downwind from ethanol distilleries were an order of magnitude higher in ethanol concentration (3090 ± 448 nM) compared to deposition collected in terrestrial locations not impacted by these sources. These results indicate that wet deposition of ethanol is heavily influenced by local sources and ethanol emission impacts on air quality may be more significant in highly populated areas. As established and developing countries continue to rapidly increase ethanol fuel consumption and subsequent emissions, understanding the magnitude of all ethanol sources and

  12. High Mercury Wet Deposition at a "Clean Air" Site in Puerto Rico.

    Science.gov (United States)

    Shanley, James B; Engle, Mark A; Scholl, Martha; Krabbenhoft, David P; Brunette, Robert; Olson, Mark L; Conroy, Mary E

    2015-10-20

    Atmospheric mercury deposition measurements are rare in tropical latitudes. Here we report on seven years (April 2005 to April 2012, with gaps) of wet Hg deposition measurements at a tropical wet forest in the Luquillo Mountains, northeastern Puerto Rico, U.S. Despite receiving unpolluted air off the Atlantic Ocean from northeasterly trade winds, during two complete years the site averaged 27.9 μg m(-2) yr(-1) wet Hg deposition, or about 30% more than Florida and the Gulf Coast, the highest deposition areas within the U.S. These high Hg deposition rates are driven in part by high rainfall, which averaged 2855 mm yr(-1). The volume-weighted mean Hg concentration was 9.8 ng L(-1), and was highest during summer and lowest during the winter dry season. Rainout of Hg (decreasing concentration with increasing rainfall depth) was minimal. The high Hg deposition was not supported by gaseous oxidized mercury (GOM) at ground level, which remained near global background concentrations (<10 pg m(-3)). Rather, a strong positive correlation between Hg concentrations and the maximum height of rain detected within clouds (echo tops) suggests that droplets in high convective cloud tops scavenge GOM from above the mixing layer. The high wet Hg deposition at this "clean air" site suggests that other tropical areas may be hotspots for Hg deposition as well.

  13. High mercury wet deposition at a “clean Air” site in Puerto Rico

    Science.gov (United States)

    Shanley, James B.; Engle, Mark A.; Scholl, Martha A.; Krabbenhoft, David P.; Brunette, Robert; Olson, Mark L.; Conroy, Mary E.

    2015-01-01

    Atmospheric mercury deposition measurements are rare in tropical latitudes. Here we report on seven years (April 2005 to April 2012, with gaps) of wet Hg deposition measurements at a tropical wet forest in the Luquillo Mountains, northeastern Puerto Rico, U.S. Despite receiving unpolluted air off the Atlantic Ocean from northeasterly trade winds, during two complete years the site averaged 27.9 μg m–2 yr–1 wet Hg deposition, or about 30% more than Florida and the Gulf Coast, the highest deposition areas within the U.S. These high Hg deposition rates are driven in part by high rainfall, which averaged 2855 mm yr–1. The volume-weighted mean Hg concentration was 9.8 ng L–1, and was highest during summer and lowest during the winter dry season. Rainout of Hg (decreasing concentration with increasing rainfall depth) was minimal. The high Hg deposition was not supported by gaseous oxidized mercury (GOM) at ground level, which remained near global background concentrations (<10 pg m–3). Rather, a strong positive correlation between Hg concentrations and the maximum height of rain detected within clouds (echo tops) suggests that droplets in high convective cloud tops scavenge GOM from above the mixing layer. The high wet Hg deposition at this “clean air” site suggests that other tropical areas may be hotspots for Hg deposition as well.

  14. Triple oxygen isotopes indicate urbanization affects sources of nitrate in wet and dry atmospheric deposition

    Science.gov (United States)

    Nelson, David M.; Tsunogai, Urumu; Ding, Dong; Ohyama, Takuya; Komatsu, Daisuke D.; Nakagawa, Fumiko; Noguchi, Izumi; Yamaguchi, Takashi

    2018-05-01

    Atmospheric nitrate deposition resulting from anthropogenic activities negatively affects human and environmental health. Identifying deposited nitrate that is produced locally vs. that originating from long-distance transport would help inform efforts to mitigate such impacts. However, distinguishing the relative transport distances of atmospheric nitrate in urban areas remains a major challenge since it may be produced locally and/or be transported from upwind regions. To address this uncertainty we assessed spatiotemporal variation in monthly weighted-average Δ17O and δ15N values of wet and dry nitrate deposition during one year at urban and rural sites along the western coast of the northern Japanese island of Hokkaido, downwind of the East Asian continent. Δ17O values of nitrate in wet deposition at the urban site mirrored those of wet and dry deposition at the rural site, ranging between ˜ +23 and +31 ‰ with higher values during winter and lower values in summer, which suggests the greater relative importance of oxidation of NO2 by O3 during winter and OH during summer. In contrast, Δ17O values of nitrate in dry deposition at the urban site were lower (+19 - +25 ‰) and displayed less distinct seasonal variation. Furthermore, the difference between δ15N values of nitrate in wet and dry nitrate deposition was, on average, 3 ‰ greater at the urban than rural site, and Δ17O and δ15N values were correlated for both forms of deposition at both sites with the exception of dry deposition at the urban site. These results suggest that, relative to nitrate in wet and dry deposition in rural environments and wet deposition in urban environments, nitrate in dry deposition in urban environments forms from relatively greater oxidation of NO by peroxy radicals and/or oxidation of NO2 by OH. Given greater concentrations of peroxy radicals and OH in cities, these results imply that dry nitrate deposition results from local NOx emissions more so than wet

  15. Atmospheric wet and dry deposition of trace elements at 10 sites in Northern China

    Science.gov (United States)

    Pan, Y. P.; Wang, Y. S.

    2015-01-01

    Atmospheric deposition is considered to be a major process that removes pollutants from the atmosphere and an important source of nutrients and contaminants for ecosystems. Trace elements (TEs), especially toxic metals deposited on plants and into soil or water, can cause substantial damage to the environment and human health due to their transfer and accumulation in food chains. Despite public concerns, quantitative knowledge of metal deposition from the atmosphere to ecosystems remains scarce. To advance our understanding of the spatiotemporal variations in the magnitudes, pathways, compositions and impacts of atmospherically deposited TEs, precipitation (rain and snow) and dry-deposited particles were collected simultaneously at 10 sites in Northern China from December 2007 to November 2010. The measurements showed that the wet and dry depositions of TEs in the target areas were orders of magnitude higher than previous observations within and outside China, generating great concern over the potential risks. The spatial distribution of the total (wet plus dry) deposition flux was consistent with that of the dry deposition, with a significant decrease from industrial and urban areas to suburban, agricultural and rural sites, while the wet deposition exhibited less spatial variation. In addition, the seasonal variation of wet deposition was also different from that of dry deposition, although they were both governed by the precipitation and emission patterns. For the majority of TEs that exist as coarse particles, dry deposition dominated the total flux at each site. This was not the case for potassium, nickel, arsenic, lead, zinc, cadmium, selenium, silver and thallium, for which the relative importance between wet and dry deposition fluxes varied by site. Whether wet deposition is the major atmospheric cleansing mechanism for the TEs depends on the size distribution of the particles. We found that atmospheric inputs of copper, lead, zinc, cadmium, arsenic and

  16. Model of wet chemical etching of swift heavy ions tracks

    Science.gov (United States)

    Gorbunov, S. A.; Malakhov, A. I.; Rymzhanov, R. A.; Volkov, A. E.

    2017-10-01

    A model of wet chemical etching of tracks of swift heavy ions (SHI) decelerated in solids in the electronic stopping regime is presented. This model takes into account both possible etching modes: etching controlled by diffusion of etchant molecules to the etching front, and etching controlled by the rate of a reaction of an etchant with a material. Olivine ((Mg0.88Fe0.12)2SiO4) crystals were chosen as a system for modeling. Two mechanisms of chemical activation of olivine around the SHI trajectory are considered. The first mechanism is activation stimulated by structural transformations in a nanometric track core, while the second one results from neutralization of metallic atoms by generated electrons spreading over micrometric distances. Monte-Carlo simulations (TREKIS code) form the basis for the description of excitations of the electronic subsystem and the lattice of olivine in an SHI track at times up to 100 fs after the projectile passage. Molecular dynamics supplies the initial conditions for modeling of lattice relaxation for longer times. These simulations enable us to estimate the effects of the chemical activation of olivine governed by both mechanisms. The developed model was applied to describe chemical activation and the etching kinetics of tracks of Au 2.1 GeV ions in olivine. The estimated lengthwise etching rate (38 µm · h-1) is in reasonable agreement with that detected in the experiments (24 µm · h-1).

  17. Air pollution: Tropospheric ozone, and wet deposition of sulfate and inorganic nitrogen

    Science.gov (United States)

    John W. Coulston

    2009-01-01

    The influence of air pollutants on ecosystems in the United States is an important environmental issue. The term “air pollution” encompasses a wide range of topics, but acid deposition and ozone are primary concerns in the context of forest health. Acid deposition partially results from emissions of sulfur dioxide, nitrogen oxides, and ammonia that are deposited in wet...

  18. Wet Deposition of Perchlorate Over the Continental United States

    Science.gov (United States)

    Rajagopalan, S.; Jackson, A. W.; Anderson, T. A.

    2007-12-01

    Natural perchlorate (ClO4-) has been detected in soil, vegetation, food products, and ground and drinking water supplies at various concentrations across the world. For almost a century natural perchlorate has been known to exist in Chilean nitrate deposits that are up to 16 million years old, and recent isotopic evidence has confirmed its source to be predominantly atmospheric. Although the source of natural perchlorate has been attributed to atmospheric deposition, there is almost no data available concerning the deposition rate of perchlorate from precipitation. This research effort, supported by SERDP, was designed to investigate the range of concentrations, and temporal and spatial variations in perchlorate deposition. Sub-samples of precipitation collected through the National Atmospheric Deposition program over a two year period were analyzed for perchlorate. Sample locations included 14 continental states, and Puerto Rico. Perchlorate has been detected (DL= 5 ng/L) in over 65 % of all samples tested with a mean value of 12.60 ± 13.60 ng/L and ranged from 0.5) between ClO4- and other ions (Cl-, NO3-, SO4-2, Na+, K+, Ca+2, Mg+2, and NH4+). Results from this study will have important implications to the national perchlorate issue and may aid in explaining the occurrence of non-anthropogenic perchlorate being reported in arid and semi-arid areas.

  19. A simple wet chemical synthesis and characterization of hydroxyapatite nanorods

    International Nuclear Information System (INIS)

    Liu Yingkai; Hou Dedong; Wang Guanghou

    2004-01-01

    Calcium hydroxyapatite (Ca 5 (PO 4 ) 3 (OH):HAP) nanorods have been synthesized successfully via wet chemical technique at low temperature in the presence of suitable surfactant. The as-made nanorods have a diameter of 50-80 nm and a length of 0.5-1.2 μm. The microstructures and composition are characterized via X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectrometer (FT-IR). The formation mechanism of HAP nanorod is discussed in detail. It has been found that nanorods are pure, there is no HAP carbonated HAP. The growth mechanism of HAP nanorods could be explained by a soft template

  20. Trace impurities in coal by wet chemical methods

    International Nuclear Information System (INIS)

    Pollock, E.N.

    1975-01-01

    In determining trace elements in coal by wet chemical methods, conventional atomic absorption spectroscopy (AAS) was used to determine Li, Be, V, Cr, Mn, Co, Ni, Cu, Zn, Ag, Cd, and Pb after dry ashing and acid dissolutions. A graphite furnace accessory was used for the flameless AAS determination of Bi, Se, Sn, Te, Be, Pb, As, Cd, Cr, Sb, and Ge. Mercury can be determined by flameless AAS after oxygen bomb combustion. Arsenic and antimony can be determined as their hydrides by AAS after low temperature ashing. Germanium, tin, bismuth, and tellurium can be determined as their hydrides by AAS after high temperature ashing. Selenium can be determined as its hydride by AAS after a special combustion procedure or after oxygen bomb combustion. Fluorine can be determined by specific ion analysis after oxygen bomb combustion. Boron can be determined colorimetrically. (U.S.)

  1. Intercomparison of rain sampers with respect to physical and chemical parameters aiming at the standardization of methods to measure wet deposition. Vergleich von Niederschlagssammlern in Hinblick auf physikalische und chemische Parameter mit dem Ziel einer Standardisierung der Messtechnik der nassen Deposition

    Energy Technology Data Exchange (ETDEWEB)

    Danecker, W

    1990-02-28

    From 1 April 1986 to 31 December 1989, with support from the BMFT till 31 March 1989, the problem of standardization of methods to measure wet deposition was investigated in cooperation with the Meteorological Observatorium Hamburg. In a large field experiment 11 different rain samplers were intercompared for a long period with respect to their suitability for measurement of wet deposition of atmospheric trace substances. The observed systematic differences could be related to specific contamination sources. In addition differing large surface effects of the rain drainage system of the samplers were investigated. Two intercalibrations were performed with the participation of 26 and 21 experienced European laboratories. The results for the 12 measured parameters in rainwater clearly show the available analytical technique of today. Statistical evaluation and return of the individual results for the participating laboratories allowed them to control their methods and check for reliability of common analytical procedures. Conclusions and results of the project have been incorporated in the VDI-guideline 3870 'Measurement of rain constituents' as well as into the report BPT 1/89 of the GSF. (orig.) With 11 refs., 57 tabs., 84 figs.

  2. Total Sulfur Deposition (wet+dry) from the Atmosphere

    Data.gov (United States)

    U.S. Environmental Protection Agency — Sulfur Dioxide (SO2) is emitted primarily as a by-product of coal combustion from power plants. Sulfur Dioxide reacts in the atmosphere to form other chemical such...

  3. Rapid Deceleration-Driven Wetting Transition during Pendant Drop Deposition on Superhydrophobic Surfaces

    Science.gov (United States)

    Kwon, Hyuk-Min; Paxson, Adam T.; Varanasi, Kripa K.; Patankar, Neelesh A.

    2011-01-01

    A hitherto unknown mechanism for wetting transition is reported. When a pendant drop settles upon deposition, there is a virtual “collision” where its center of gravity undergoes rapid deceleration. This induces a high water hammer-type pressure that causes wetting transition. A new phase diagram shows that both large and small droplets can transition to wetted states due to the new deceleration driven and the previously known Laplace mechanisms, respectively. It is explained how the attainment of a nonwetted Cassie-Baxter state is more restrictive than previously known.

  4. Chemical vapour deposition of carbon nanotubes

    CSIR Research Space (South Africa)

    Arendse, CJ

    2006-02-01

    Full Text Available , effective, more versatile and easily scalable to large substrate sizes. In this paper, we present a design of the hot-wire CVD system constructed at the CSIR for the deposition of CNTs. Additionally, we will report on the structure of CNTs deposited... exhibit exceptional chemical and physical properties related to toughness, chemical inertness, magnetism, and electrical and thermal conductivity. A variety of preparation methods to synthesise CNTs are known, e.g. carbon-arc discharge, laser ablation...

  5. Quantum confinement of lead titanate nanocrystals by wet chemical method

    Energy Technology Data Exchange (ETDEWEB)

    Kaviyarasu, K., E-mail: kaviyarasuloyolacollege@gmail.com [UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology Laboratories, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, P O Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), Materials Research Department (MSD), iThemba LABS-National Research Foundation - NRF, 1 Old Faure Road, 7129, P O Box 722, Somerset West, Western Cape Province (South Africa); Manikandan, E., E-mail: maniphysics@gmail.com [Nanosciences African Network (NANOAFNET), Materials Research Department (MSD), iThemba LABS-National Research Foundation - NRF, 1 Old Faure Road, 7129, P O Box 722, Somerset West, Western Cape Province (South Africa); Central Research Laboratory, Sree Balaji Medical College & Hospital, Bharath University, Chrompet, Chennai, Tamil Nadu (India); Nuru, Z.Y. [UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology Laboratories, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, P O Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), Materials Research Department (MSD), iThemba LABS-National Research Foundation - NRF, 1 Old Faure Road, 7129, P O Box 722, Somerset West, Western Cape Province (South Africa); Maaza, M., E-mail: likmaaz@gmail.com [UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology Laboratories, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, P O Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), Materials Research Department (MSD), iThemba LABS-National Research Foundation - NRF, 1 Old Faure Road, 7129, P O Box 722, Somerset West, Western Cape Province (South Africa)

    2015-11-15

    Lead Titanate (PbTiO{sub 3)} is a category of the practical semiconductor metal oxides, which is widely applied in various scientific and industrial fields because of its catalytic, optical, and electrical properties. PbTiO{sub 3} nanocrystalline materials have attracted a wide attention due to their unique properties. PbTiO{sub 3} nanocrystals were investigated by X-ray diffraction (XRD) to identify the PbTiO{sub 3} nanocrystals were composed a tetragonal structure. The diameter of a single sphere was around 20 nm and the diameter reached up to 3 μm. The chemical composition of the samples and the valence states of elements were determined by X-ray photoelectron spectroscopy (XPS) in detail. - Highlights: • Single crystalline NSs of PbTiO{sub 3} fabricated by wet chemical method. • PbTiO{sub 3} NSs were uniform and continuous along the long axis. • Tetragonal perovskite structure with the diameter 20 nm and length 3 μm. • XPS spectrum was fitted with Lorentzian function respectively. • The size of the images is also 10 μm × 10 μm.

  6. Indium tin oxide films prepared via wet chemical route

    International Nuclear Information System (INIS)

    Legnani, C.; Lima, S.A.M.; Oliveira, H.H.S.; Quirino, W.G.; Machado, R.; Santos, R.M.B.; Davolos, M.R.; Achete, C.A.; Cremona, M.

    2007-01-01

    In this work, indium tin oxide (ITO) films were prepared using a wet chemical route, the Pechini method. This consists of a polyesterification reaction between an α-hydroxicarboxylate complex (indium citrate and tin citrate) with a polyalcohol (ethylene glycol) followed by a post annealing at 500 deg. C. A 10 at.% of doping of Sn 4+ ions into an In 2 O 3 matrix was successfully achieved through this method. In order to characterize the structure, the morphology as well as the optical and electrical properties of the produced ITO films, they were analyzed using different experimental techniques. The obtained films are highly transparent, exhibiting transmittance of about 85% at 550 nm. They are crystalline with a preferred orientation of [222]. Microscopy discloses that the films are composed of grains of 30 nm average size and 0.63 nm RMS roughness. The films' measured resistivity, mobility and charge carrier concentration were 5.8 x 10 -3 Ω cm, 2.9 cm 2 /V s and - 3.5 x 10 20 /cm 3 , respectively. While the low mobility value can be related to the small grain size, the charge carrier concentration value can be explained in terms of the high oxygen concentration level resulting from the thermal treatment process performed in air. The experimental conditions are being refined to improve the electrical characteristics of the films while good optical, chemical, structural and morphological qualities already achieved are maintained

  7. Five-year records of mercury wet deposition flux at GMOS sites in the Northern and Southern hemispheres

    Science.gov (United States)

    Sprovieri, Francesca; Pirrone, Nicola; Bencardino, Mariantonia; D'Amore, Francesco; Angot, Helene; Barbante, Carlo; Brunke, Ernst-Günther; Arcega-Cabrera, Flor; Cairns, Warren; Comero, Sara; Diéguez, María del Carmen; Dommergue, Aurélien; Ebinghaus, Ralf; Feng, Xin Bin; Fu, Xuewu; Garcia, Patricia Elizabeth; Gawlik, Bernd Manfred; Hageström, Ulla; Hansson, Katarina; Horvat, Milena; Kotnik, Jože; Labuschagne, Casper; Magand, Olivier; Martin, Lynwill; Mashyanov, Nikolay; Mkololo, Thumeka; Munthe, John; Obolkin, Vladimir; Ramirez Islas, Martha; Sena, Fabrizio; Somerset, Vernon; Spandow, Pia; Vardè, Massimiliano; Walters, Chavon; Wängberg, Ingvar; Weigelt, Andreas; Yang, Xu; Zhang, Hui

    2017-02-01

    The atmospheric deposition of mercury (Hg) occurs via several mechanisms, including dry and wet scavenging by precipitation events. In an effort to understand the atmospheric cycling and seasonal depositional characteristics of Hg, wet deposition samples were collected for approximately 5 years at 17 selected GMOS monitoring sites located in the Northern and Southern hemispheres in the framework of the Global Mercury Observation System (GMOS) project. Total mercury (THg) exhibited annual and seasonal patterns in Hg wet deposition samples. Interannual differences in total wet deposition are mostly linked with precipitation volume, with the greatest deposition flux occurring in the wettest years. This data set provides a new insight into baseline concentrations of THg concentrations in precipitation worldwide, particularly in regions such as the Southern Hemisphere and tropical areas where wet deposition as well as atmospheric Hg species were not investigated before, opening the way for future and additional simultaneous measurements across the GMOS network as well as new findings in future modeling studies.

  8. Laser-induced chemical vapor deposition reactions

    International Nuclear Information System (INIS)

    Teslenko, V.V.

    1990-01-01

    The results of investigation of chemical reactions of deposition of different substances from the gas phase when using the energy of pulse quasicontinuous and continuous radiation of lasers in the wave length interval from 0.193 to 10.6 μm are generalized. Main attetion is paid to deposition of inorganic substances including nonmetals (C, Si, Ge and others), metals (Cu, Au, Zn, Cd, Al, Cr, Mo, W, Ni) and some simple compounds. Experimental data on the effect of laser radiation parameters and reagent nature (hydrides, halogenides, carbonyls, alkyl organometallic compounds and others) on the deposition rate and deposit composition are described in detail. Specific features of laser-chemical reactions of deposition and prospects of their application are considered

  9. Conditioning of Si-interfaces by wet-chemical oxidation: Electronic interface properties study by surface photovoltage measurements

    International Nuclear Information System (INIS)

    Angermann, Heike

    2014-01-01

    Highlights: • Determination of electronic interface properties by contact-less surface photovoltage (SPV) technique. • Systematic correlations of substrate morphology and surface electronic properties. • Optimization of surface pre-treatment for flat, saw damage etched, and textured Si solar cell substrates. • Ultra-thin passivating Si oxide layers with low densities of rechargeable states by wet-chemical oxidation and subsequent annealing. • Environmentally acceptable processes, utilizing hot water, diluted HCl, or ozone low cost alternative to current approaches with concentrated chemicals. • The effect of optimized wet-chemical pre-treatments can be preserved during subsequent layer deposition. - Abstract: The field-modulated surface photovoltage (SPV) method, a very surface sensitive technique, was utilized to determine electronic interface properties on wet-chemically oxidized and etched silicon (Si) interfaces. The influence of preparation-induced surface micro-roughness and un-stoichiometric oxides on the resulting the surface charge, energetic distribution D it (E), and density D it,min of rechargeable states was studied by simultaneous, spectroscopic ellipsometry (SE) measurements on polished Si(111) and Si(100) substrates. Based on previous findings and new research, a study of conventional and newly developed wet-chemical oxidation methods was established, correlating the interactions between involved oxidizing and etching solutions and the initial substrate morphology to the final surface conditioning. It is shown, which sequences of wet-chemical oxidation and oxide removal, have to be combined in order to achieve atomically smooth, hydrogen terminated surfaces, as well as ultra-thin oxide layers with low densities of rechargeable states on flat, saw damage etched, and textured Si substrates, as commonly applied in silicon device and solar cell manufacturing. These conventional strategies for wet-chemical pre-treatment are mainly based on

  10. Characterizations of wet mercury deposition to a remote islet (Pengjiayu) in the subtropical Northwest Pacific Ocean

    Science.gov (United States)

    Sheu, Guey-Rong; Lin, Neng-Huei

    2013-10-01

    Thirty-four weekly rainwater samples were collected in 2009 at Pengjiayu, a remote islet in the subtropical Northwest (NW) Pacific Ocean, to study the distribution of rainwater mercury (Hg) concentrations and associated wet deposition fluxes. This is the first study concerning wet Hg deposition to the subtropical NW Pacific Ocean downwind of the East Asian continent, which is the major source region for Hg emissions worldwide. Sample Hg concentrations ranged from 2.25 to 22.33 ng L-1, with a volume-weighted mean (VWM) concentration of 8.85 ng L-1. The annual wet Hg deposition flux was 10.18 μg m-2, about 2.5 times the fluxes measured at sites on the Pacific coast of the USA, supporting the hypothesis that deposition is higher in the western than in the eastern Pacific. Seasonal VWM concentrations were 7.23, 11.58, 7.82, and 9.84 ng L-1, whereas seasonal wet deposition fluxes were 2.14, 3.45, 2.38, and 2.21 μg m-2, for spring, summer, fall and winter, respectively. Higher summer wet Hg deposition was a function of both higher rainwater Hg concentration and greater rainfall. The seasonal pattern of rainwater Hg concentrations was the opposite of the general seasonal pattern of the East Asian air pollutant export. Since there is no significant anthropogenic Hg emission source on the islet of Pengjiayu, the observed high summertime rainwater Hg concentration hints at the importance of Hg0 oxidation and/or scavenging of upper-altitude reactive gaseous Hg (RGM) by deep convection. Direct anthropogenic RGM emissions from the East Asian continent may not contribute significantly to the rainwater Hg concentrations, but anthropogenic Hg0 emissions could be transported to the upper troposphere or marine boundary layer (MBL) where they can be oxidized to produce RGM, which will then be effectively scavenged by cloud water and rainwater.

  11. Analysis of uncertainties in CRAC2 calculations: wet deposition and plume rise

    International Nuclear Information System (INIS)

    Ward, R.C.; Kocher, D.C.; Hicks, B.B.; Hosker, R.P. Jr.; Ku, J.Y.; Rao, K.S.

    1984-01-01

    We have studied the sensitivity of results from the CRAC2 computer code, which predicts health impacts from a reactor-accident scenario, to uncertainties in selected meteorological models and parameters. The sources of uncertainty examined include the models for plume rise and wet deposition and the meteorological bin-sampling procedure. An alternative plume-rise model usually had little effect on predicted health impacts. In an alternative wet-deposition model, the scavenging rate depends only on storm type, rather than on rainfall rate and atmospheric stability class as in the CRAC2 model. Use of the alternative wet-deposition model in meteorological bin-sampling runs decreased predicted mean early injuries by as much as a factor of 2 to 3 and, for large release heights and sensible heat rates, decreased mean early fatalities by nearly an order of magnitude. The bin-sampling procedure in CRAC2 was expanded by dividing each rain bin into four bins that depend on rainfall rate. Use of the modified bin structure in conjunction with the CRAC2 wet-deposition model changed all predicted health impacts by less than a factor of 2. 9 references

  12. Meteorological effects on Hg wet deposition in a forested site in the Adirondack region of New York during 2000-2015

    Science.gov (United States)

    Mao, Huiting; Ye, Zhuyun; Driscoll, Charles

    2017-11-01

    An analysis of weekly measurement data of mercury (Hg) wet deposition was conducted for Huntington Wildlife Forest (HWF), a forest ecosystem in Upstate New York and a biological Hg hotspot, during 2000-2015. Annual accumulated Hg wet deposition flux was found to decrease at a rate of -0.13 μg m-2 yr-1 (2% yr-1) (p = 0.09), and volume weighted mean (VWM) Hg precipitation concentrations at -0.14 ng L-1 yr-1 (2.5% yr-1) (p = 0.00). In examining data by season, no trends were identified for the two variables. It was found that the North Atlantic Oscillation (NAO) affected Hg wet deposition predominantly in spring, as did the position of the U.S. East Coast trough in summer, which suggests different dominant mechanisms driving Hg wet deposition in different seasons. The impacts of such large scale circulation processes were facilitated via variations in precipitation amounts. This was manifested in spring 2011 with the strongest positive phase of NAO, resulting in the wettest spring with the largest Hg wet deposition flux, and in summer 2007 with the U.S. East Coast trough positioned the farthest out over the Atlantic Ocean, causing the driest summer with the lowest Hg wet deposition flux of the study period. Extreme precipitation amounts in spring could singularly drive the overall long-term trend in Hg wet deposition whereas in summer other factors could just be as important. Similar mechanisms were thought to control the long term variations of Hg wet deposition and precipitation concentrations in all seasons but summer as indicated in their significant correlation in all but summer. Atmospheric concentrations of gaseous oxidized mercury (GOM) and particulate borne mercury (PBM) at HWF over 2009-2015 hardly exhibited correlations with Hg wet deposition or precipitation concentrations. Chemical transport model simulations strongly supported efficient scavenging of oxidized Hg by precipitation resulting in the lowest concentration of GOM in the warm season despite the

  13. Characterization of deep wet etching of fused silica glass for single cell and optical sensor deposition

    International Nuclear Information System (INIS)

    Zhu, Haixin; Holl, Mark; Ray, Tathagata; Bhushan, Shivani; Meldrum, Deirdre R

    2009-01-01

    The development of a high-throughput single-cell metabolic rate monitoring system relies on the use of transparent substrate material for a single cell-trapping platform. The high optical transparency, high chemical resistance, improved surface quality and compatibility with the silicon micromachining process of fused silica make it very attractive and desirable for this application. In this paper, we report the results from the development and characterization of a hydrofluoric acid (HF) based deep wet-etch process on fused silica. The pin holes and notching defects of various single-coated masking layers during the etching are characterized and the most suitable masking materials are identified for different etch depths. The dependence of the average etch rate and surface roughness on the etch depth, impurity concentration and HF composition are also examined. The resulting undercut from the deep HF etch using various masking materials is also investigated. The developed and characterized process techniques have been successfully implemented in the fabrication of micro-well arrays for single cell trapping and sensor deposition. Up to 60 µm deep micro-wells have been etched in a fused silica substrate with over 90% process yield and repeatability. To our knowledge, such etch depth has never been achieved in a fused silica substrate by using a non-diluted HF etchant and a single-coated masking layer at room temperature

  14. Interception of wet deposited atmospheric pollutants by herbaceous vegetation: Data review and modelling

    Energy Technology Data Exchange (ETDEWEB)

    Gonze, M.-A., E-mail: marc-andre.gonze@irsn.fr; Sy, M.M.

    2016-09-15

    Better understanding and predicting interception of wet deposited pollutants by vegetation remains a key issue in risk assessment studies of atmospheric pollution. We develop different alternative models, following either empirical or semi-mechanistic descriptions, on the basis of an exhaustive dataset consisting of 440 observations obtained in controlled experiments, from 1970 to 2014, for a wide variety of herbaceous plants, radioactive substances and rainfall conditions. The predictive performances of the models and the uncertainty/variability of the parameters are evaluated under Hierarchical Bayesian modelling framework. It is demonstrated that the variability of the interception fraction is satisfactorily explained and quite accurately modelled by a process-based alternative in which absorption of ionic substances onto the foliage surfaces is determined by their electrical valence. Under this assumption, the 95% credible interval of the predicted interception fraction encompasses 81% of the observations, including situations where either plant biomass or rainfall intensity are unknown. This novel approach is a serious candidate to challenge existing empirical relationships in radiological or chemical risk assessment tools. - Highlights: • Literature data on the interception of atmospheric pollutants by herbs were reviewed • Predictive models were developed and evaluated in the Bayesian modelling framework • Sensitivity of interception to environmental conditions was satisfactorily explained • 81% of the observations were satisfactorily predicted by a semi-mechanistic model • This model challenges empirical relationships currently used in risk assessment tools.

  15. Dry and wet "deposition" studies of the degradation of cement mortars

    Directory of Open Access Journals (Sweden)

    Martínez-Ramírez, S.

    1998-06-01

    Full Text Available The reaction of portland cement mortars with SO2 gaseous pollutant and artificial 'acid rain' solution has been examined using laboratory exposure chambers, with realistic presentation rates of pollutants. The mortar were previously carbonated to produce superficial carbonation. Two mortars with different w/c ratio and hence specific surface were prepared and exposed into the chambers. For dry deposition of SO2 pollutant gas, the important roles of water and water plus oxidant in increasing chemical reaction are readily revealed. Further, accessible porosity also increases reaction through increased times of reaction of pollutant with the mortars. Interestingly, in the absence of deliberate surface wetting, the presence of oxidant, ozone, leads to a reduction in the already limited extent of reaction. Wet deposition studies using artificial 'acid rain' solution result in gypsum formation, which is more extensive for mortars of increased w/c ratios.

    Se han realizado ensayos de laboratorio de simulación de los procesos ambientales de "deposición" seca y húmeda sobre morteros de cemento portland, estudiándose las reacciones que se producen con el contaminante SO2 ("deposición" seca y la disolución de 'lluvia acida' ("deposición" húmeda. Los morteros de cemento se carbonataron para favorecer la carbonatación superficial de los mismos. Se prepararon morteros con dos relaciones a/c con el fin de estudiar la influencia que la variable superficie específica tenía en el proceso de deterioro de dichos materiales. En los estudios de deposición seca con SO2 como gas agresivo se ha visto la importancia que el agua y el agua junto a un oxidante tienen en la reacción del contaminante con los componentes del mortero. La superficie específica Juega un papel importante, ya que al aumentar, aumenta la reacción con el contaminante. La reacción en presencia de oxidante, (SO2+O3

  16. Radiocaesium activity in rape oil and in rape cake after a wet deposition event

    Energy Technology Data Exchange (ETDEWEB)

    Chaiko, Y.; Rappe-George, M.; Bengtsson, S. [Department of Soil and Environment (Sweden)

    2014-07-01

    After a release of radionuclides in agricultural areas there can be concerns on the levels of radionuclides in food products produced. The uptake of radionuclides via the above ground plant parts is a very important transport route into the food chain for humans as caesium is relatively mobile inside plants. In the production of rape oil the use of a processing factor (Pf) is used to estimate the activity concentration of radioactivity in the final oil product based on the activity concentration in rape seeds. The processing factor has been estimated to be 0.004 for caesium in rape oil by IAEA, and is based on a limited numbers of studies (1). In this project we analysed the activity concentration of radiocaesium ({sup 134}Cs) in rape oil and in rape cake from rape seeds contaminated after a wet deposition event with {sup 134}Cs. With the information of activity concentration of {sup 134}Cs in rape oil and in rape cake, we calculated the Pf-value and confirm or suggest new enhanced Pf-value. We analysed the activity concentration of {sup 134}Cs in rape oil and in rape cake from spring oilseed rape seeds (Brassica napus L.) that had been contaminated experimentally by wet deposited {sup 134}Cs in an earlier experiment by Bengtsson et al. (2013). The estimation of activity concentration of {sup 134}Cs in rape oil and in rape cake was achieved by performing extraction of the oil (and other extractable compounds) from the seeds based on the Randall extraction method (Randall, 1974) using petroleum ether as extraction chemical. The extracted oil and the rape cake samples were weighed and the activity concentration was measured with High-Purity Germanium (HPGe) detectors. Pf-values were calculated by dividing the measured activity concentration in rape oil after extraction by the activity concentration in oilseed rape seeds before extraction. Results from the present study will be presented at the international conference on radioecology and environmental radioactivity

  17. Modeling wet deposition and concentration of inorganics over Northeast Asia with MRI-PM/c

    Directory of Open Access Journals (Sweden)

    M. Kajino

    2012-11-01

    Full Text Available We conducted a regional-scale simulation over Northeast Asia for the year 2006 using an aerosol chemical transport model, with time-varying lateral and upper boundary concentrations of gaseous species predicted by a global stratospheric and tropospheric chemistry-climate model. The present one-way nested global-through-regional-scale model is named the Meteorological Research Institute–Passive-tracers Model system for atmospheric Chemistry (MRI-PM/c. We evaluated the model's performance with respect to the major anthropogenic and natural inorganic components, SO42−, NH4+, NO3, Na+ and Ca2+ in the air, rain and snow measured at the Acid Deposition Monitoring Network in East Asia (EANET stations. Statistical analysis showed that approximately 40–50 % and 70–80 % of simulated concentration and wet deposition of SO42−, NH4+, NO3and Ca2+ are within factors of 2 and 5 of the observations, respectively. The prediction of the sea-salt originated component Na+ was not successful at near-coastal stations (where the distance from the coast ranged from 150 to 700 m, because the model grid resolution (Δx=60 km is too coarse to resolve it. The simulated Na+ in precipitation was significantly underestimated by up to a factor of 30.

  18. Model study on acidifying wet deposition in East Asia during wintertime

    Science.gov (United States)

    Han, Zhiwei; Ueda, Hiromasa; Sakurai, Tatsuya

    A regional air quality model (RAQM) has been developed and applied together with an aerosol model to investigate the states and characteristics of wet deposition in East Asia in December 2001. Model simulation is performed with monthly based emission inventory [Streets, D.G., Bond, T.C., Carmichael, G.R., Fernandes, S.D., Fu, Q., He, D., Klimont, Z., Nelson, S. M., Tsai, N.Y., Wang, M.Q., Woo, J.-H., Yarber, K.F., 2003. An inventory of gaseous and primary emissions in Asia in the year 2000. Journal of Geophysical Research 108(D21), 8809] and meteorological fields derived from MM5. Model results are compared with extensive monitoring data including relevant gaseous species and ions in precipitation. The validation demonstrates that this model system is able to represent most of the major physical and chemical processes involved in acid deposition and reproduces concentrations reasonably well, within a factor of 2 of observations in general. The study shows that the regions with pH less than 4.5 are mainly located in southwestern China, parts of the Yangtze Delta, the Yellow Sea and the Korean peninsula, indicating wide regions of acid precipitation in East Asia in wintertime. Japan islands mainly exhibit pH values of 4.5-5.0, whereas over wide areas of northern China, pH values are relatively high (⩾5.0) due to neutralization by alkaline materials such as calcium-laden particles and ammonia, which are more abundant in northern China than that in southern China. While acid rain over most of China is still characterized by sulfur-induced type, considerable areas of eastern China and the western Pacific Rim are found to be more affected by nitric acid than sulfuric acid in acidification of precipitation, which is supposed to result from a combined effect of variations in photochemistry and emission, suggesting the increasing importance of NO x emission in these regions.

  19. Wet and Dry Atmospheric Mercury Deposition Accumulates in Watersheds of the Northeastern United States

    Science.gov (United States)

    Boyer, E. W.; Grant, C.; Grimm, J.; Drohan, P. J.; Bennett, J.; Lawler, D.

    2013-12-01

    Mercury emissions to the atmosphere from coal-fired power plants and other sources such as waste incineration can be deposited to landscapes in precipitation and in dry fallout. Some mercury reaches watersheds and streams, where it can accumulate in sediments and biota. Human exposure to mercury occurs primarily through fish consumption, and currently mercury fish eating advisories are in place for many of the streams and lakes in the state. Here, we explored mercury in air, soils, water, and biota. To quantify atmospheric mercury deposition, we measured both wet and dry mercury deposition at over 10 locations in Pennsylvania, from which we present variation in mercury deposition and initial assessments of factors affecting the patterns. Further, we simulated mercury deposition at unmonitored locations in Pennsylvania and the northeastern United States over space and time with a high-resolution modeling technique that reflects storm tracks and air flow patterns. To consider mercury accumulation in watersheds, we collected data on soil mercury concentrations in a set of soil samples, and collected baseline data on mercury in streams draining 35 forested watersheds across Pennsylvania, spanning gradients of atmospheric deposition, climate and geology. Mercury concentrations were measured in stream water under base-flow conditions, in streambed sediments, aquatic mosses, and in fish tissues from brook trout. Results indicate that wet and dry atmospheric deposition is a primary source of mercury that is accumulating in watersheds of Pennsylvania and the northeastern United States.

  20. Sulfate-rich eolian and wet interdune deposits, erebus crater, meridiani Planum, Mars

    Science.gov (United States)

    Metz, J.M.; Grotzinger, J.P.; Rubin, D.M.; Lewis, K.W.; Squyres, S. W.; Bell, J.F.

    2009-01-01

    This study investigates three bedrock exposures at Erebus crater, an ?? 300 m diameter crater approximately 4 km south of Endurance crater on Mars. These outcrops, called Olympia, Payson, and Yavapai, provide additional evidence in support of the dune-interdune model proposed for the formation of the deposits at the Opportunity landing site in Meridiani Planum. There is evidence for greater involvement of liquid water in the Olympia outcrop exposures than was observed in Eagle or Endurance craters. The Olympia outcrop likely formed in a wet interdune and sand sheet environment. The facies observed within the Payson outcrop, which is likely stratigraphically above the Olympia outcrop, indicate that it was deposited in a damp-wet interdune, sand sheet, and eolian dune environment. The Yavapai outcrop, which likely stratigraphically overlies the Payson outcrop, indicates that it was deposited in primarily a sand sheet environment and also potentially in an eolian dune environment. These three outcrop exposures may indicate an overall drying-upward trend spanning the stratigraphic section from its base at the Olympia outcrop to its top at the Yavapai outcrop. This contrasts with the wetting-upward trend seen in Endurance and Eagle craters. Thus, the series of outcrops seen at Meridiani by Opportunity may constitute a full climatic cycle, evolving from dry to wet to dry conditions. ?? 2009, SEPM (Society for Sedimentary Geology).

  1. Wetting, Solubility and Chemical Characteristics of Plasma-Polymerized 1-Isopropyl-4-Methyl-1,4-Cyclohexadiene Thin Films

    Directory of Open Access Journals (Sweden)

    Jakaria Ahmad

    2014-07-01

    Full Text Available Investigations on the wetting, solubility and chemical composition of plasma polymer thin films provide an insight into the feasibility of implementing these polymeric materials in organic electronics, particularly where wet solution processing is involved. In this study, thin films were prepared from 1-isopropyl-4-methyl-1,4-cyclohexadiene (γ-Terpinene using radio frequency (RF plasma polymerization. FTIR showed the polymers to be structurally dissimilar to the original monomer and highly cross-linked, where the loss of original functional groups and the degree of cross-linking increased with deposition power. The polymer surfaces were hydrocarbon-rich, with oxygen present in the form of O–H and C=O functional groups. The oxygen content decreased with deposition power, with films becoming more hydrophobic and, thus, less wettable. The advancing and receding contact angles were investigated, and the water advancing contact angle was found to increase from 63.14° to 73.53° for thin films prepared with an RF power of 10 W to 75 W. The wetting envelopes for the surfaces were constructed to enable the prediction of the surfaces’ wettability for other solvents. The effect of roughness on the wetting behaviour of the films was insignificant. The polymers were determined to resist solubilization in solvents commonly used in the deposition of organic semiconducting layers, including chloroform and chlorobenzene, with higher stability observed in films fabricated at higher RF power.

  2. Chronic nitrogen deposition influences the chemical dynamics ...

    Science.gov (United States)

    Atmospheric nitrogen deposition induces a forest carbon sink across broad parts of the Northern Hemisphere; this carbon sink may partly result from slower litter decomposition. Although microbial responses to experimental nitrogen deposition have been well-studied, evidence linking these microbial responses to changes in the degradation of specific compounds in decaying litter is sparse. We used wet chemistry and Fourier transform infrared spectroscopy (FTIR) methodologies to study the effects of chronic simulated nitrogen deposition on leaf litter and fine root chemistry during a three-year decomposition experiment at four northern hardwood forests in the north-central USA. Leaf litter and fine roots were highly different in initial chemistry such as concentrations of acid-insoluble fraction (AIF, or Klason lignin) and condensed tannins (CTs). These initial differences persisted over the course of decomposition. Results from gravimetrically-defined AIF and lignin/carbohydrate reference IR peak ratios both provide evidence that lignin in fine roots was selectively preserved under simulated nitrogen deposition. Lignin/carbohydrate peak ratios were strongly correlated with AIF, suggesting that AIF is a good predictor of lignin. Because AIF is abundant in fine roots, slower AIF degradation was the major driver of the slower fine root decomposition under nitrogen enrichment, explaining 73.9 % of the additional root mass retention. Nitrogen enrichment also slowed the

  3. Trends in bromide wet deposition concentrations in the contiguous United States, 2001-2016.

    Science.gov (United States)

    Wetherbee, Gregory A; Lehmann, Christopher M B; Kerschner, Brian M; Ludtke, Amy S; Green, Lee A; Rhodes, Mark F

    2018-02-01

    Bromide (Br - ) and other solute concentration data from wet deposition samples collected and analyzed by the National Atmospheric Deposition Program (NADP) from 2001 to 2016, were statistically analyzed for trends both geographically and temporally by precipitation type. Analysis was limited to NADP sites in the contiguous 48 United States. The Br - concentrations for this time period had a high number of values censored at the detection limits with greater than 86 percent of sample concentrations below analytical detection. Bromide was more frequently detected at NADP sites in coastal regions. Analysis using specialized statistical techniques for censored data revealed that Br - concentrations varied by precipitation type with higher concentrations usually observed in liquid versus precipitation containing snow. Negative temporal trends in Br - wet deposition concentrations were observed at a majority of NADP sites; approximately 25 percent of these trend values were statistically significant at less than 0.05 to 0.10 significance levels. Potential causes for the negative trends were explored, including annual and seasonal changes in precipitation depth, reduced emissions of methyl bromide (CH 3 Br) from coastal wetlands, and declining industrial use of bromine compounds. The results indicate that Br - in non-coastal wet-deposition comes mainly from long-range transport, not local sources. Correlations between Br - , chloride, and nitrate concentrations also were evaluated. Published by Elsevier Ltd.

  4. Controlling Factors of Mercury Wet Deposition and Precipitation Concentrations in Upstate New York

    Science.gov (United States)

    Ye, Z.; Mao, H.; Driscoll, C. T.

    2017-12-01

    Observations from the Mercury Deposition Network (MDN) at Huntington Wildlife Forest (HWF) suggested that a significant decline in Hg concentrations in precipitation was linked to Hg emission decreases in the United States, especially in the Northeast and Midwest, and yet Hg wet deposition has remained fairly constant over the past two decades. The present study was aimed to investigate how climatic, terrestrial, and anthropogenic factors had influenced the Hg wet deposition flux in upstate New York (NY). To achieve this, an improved Community Multiscale Air Quality (CMAQ) model was employed, which included state-of-the-art Hg and halogen chemistry mechanisms. A base simulation and five sensitivity simulations were conducted. The base simulation used 2010 meteorology, U.S. EPA NEI 2011, and GEOS-Chem output as initial and boundary conditions (ICs and BCs). The five sensitivity runs each changed one condition at the time as follows: 1-3) 2004, 2005, and 2007 meteorology instead of 2010, 4) NEI 2005 Hg anthropogenic emission out of NYS instead of NEI 2011, and 5) no in-state Hg anthropogenic emission. The study period of all the simulations was March - November 2010, and the domain covered the northeastern United States at 12 km resolution. As a result, compared with rural areas in NYS, Hg wet deposition and ambient Hg concentrations in urban areas were affected more significantly by in-state anthropogenic Hg emission. The in-state anthropogenic Hg emissions contributed up to 20% of Hg wet deposition at urban sites and cloud height, precipitation, wind speed and direction, and relative humidity, among which precipitation had the largest effects in most areas. Diluting effects were found in non-convective precipitation, which contributed 31-48% to changes in Hg concentration in precipitation.

  5. Wet and Dry Atmospheric Depositions of Inorganic Nitrogen during Plant Growing Season in the Coastal Zone of Yellow River Delta

    Directory of Open Access Journals (Sweden)

    Junbao Yu

    2014-01-01

    Full Text Available The ecological problems caused by dry and wet deposition of atmospheric nitrogen have been widespread concern in the world. In this study, wet and dry atmospheric depositions were monitored in plant growing season in the coastal zone of the Yellow River Delta (YRD using automatic sampling equipment. The results showed that SO42- and Na+ were the predominant anion and cation, respectively, in both wet and dry atmospheric depositions. The total atmospheric nitrogen deposition was ~2264.24 mg m−2, in which dry atmospheric nitrogen deposition was about 32.02%. The highest values of dry and wet atmospheric nitrogen deposition appeared in May and August, respectively. In the studied area, NO3-–N was the main nitrogen form in dry deposition, while the predominant nitrogen in wet atmospheric deposition was NH4+–N with ~56.51% of total wet atmospheric nitrogen deposition. The average monthly attribution rate of atmospheric deposition of NO3-–N and NH4+–N was ~31.38% and ~20.50% for the contents of NO3-–N and NH4+–N in 0–10 cm soil layer, respectively, suggested that the atmospheric nitrogen was one of main sources for soil nitrogen in coastal zone of the YRD.

  6. Wet and dry atmospheric depositions of inorganic nitrogen during plant growing season in the coastal zone of Yellow River Delta.

    Science.gov (United States)

    Yu, Junbao; Ning, Kai; Li, Yunzhao; Du, Siyao; Han, Guangxuan; Xing, Qinghui; Wu, Huifeng; Wang, Guangmei; Gao, Yongjun

    2014-01-01

    The ecological problems caused by dry and wet deposition of atmospheric nitrogen have been widespread concern in the world. In this study, wet and dry atmospheric depositions were monitored in plant growing season in the coastal zone of the Yellow River Delta (YRD) using automatic sampling equipment. The results showed that SO4 (2-) and Na(+) were the predominant anion and cation, respectively, in both wet and dry atmospheric depositions. The total atmospheric nitrogen deposition was ~2264.24 mg m(-2), in which dry atmospheric nitrogen deposition was about 32.02%. The highest values of dry and wet atmospheric nitrogen deposition appeared in May and August, respectively. In the studied area, NO3 (-)-N was the main nitrogen form in dry deposition, while the predominant nitrogen in wet atmospheric deposition was NH4 (+)-N with ~56.51% of total wet atmospheric nitrogen deposition. The average monthly attribution rate of atmospheric deposition of NO3 (-)-N and NH4 (+)-N was ~31.38% and ~20.50% for the contents of NO3 (-)-N and NH4 (+)-N in 0-10 cm soil layer, respectively, suggested that the atmospheric nitrogen was one of main sources for soil nitrogen in coastal zone of the YRD.

  7. Size dependent optical characteristics of chemically deposited

    Indian Academy of Sciences (India)

    Keywords. Thin film; ZnS; CBD method; optical properties. Abstract. ZnS thin films of different thicknesses were prepared by chemical bath deposition using thiourea and zinc acetate as S2- and Zn2+ source. The effect of film thickness on the optical and structural properties was studied. The optical absorption studies in the ...

  8. Chemical effect on ozone deposition over seawater

    Science.gov (United States)

    Surface layer resistance plays an important role in determining ozone deposition velocity over seawater. Recent studies suggest that surface layer resistance over sea-water is influenced by wind-speed and chemical interaction at the air-water interface. Here, we investigate the e...

  9. Trends in mercury wet deposition and mercury air concentrations across the U.S. and Canada

    Science.gov (United States)

    Weiss-Penzias, Peter S.; Gay, David A.; Brigham, Mark E.; Parsons, Matthew T.; Gustin, Mae S.; ter Shure, Arnout

    2016-01-01

    This study examined the spatial and temporal trends of mercury (Hg) in wet deposition and air concentrations in the United States (U.S.) and Canada between 1997 and 2013. Data were obtained from the National Atmospheric Deposition Program (NADP) and Environment Canada monitoring networks, and other sources. Of the 19 sites with data records from 1997–2013, 53% had significant negative trends in Hg concentration in wet deposition, while no sites had significant positive trends, which is in general agreement with earlier studies that considered NADP data up until about 2010. However, for the time period 2007–2013 (71 sites), 17% and 13% of the sites had significant positive and negative trends, respectively, and for the time period 2008–2013 (81 sites) 30% and 6% of the sites had significant positive and negative trends, respectively. Non-significant positive tendencies were also widespread. Regional trend analyses revealed significant positive trends in Hg concentration in the Rocky Mountains, Plains, and Upper Midwest regions for the recent time periods in addition to significant positive trends in Hg deposition for the continent as a whole. Sulfate concentration trends in wet deposition were negative in all regions, suggesting a lower importance of local Hg sources. The trend in gaseous elemental Hg from short-term datasets merged as one continuous record was broadly consistent with trends in Hg concentration in wet deposition, with the early time period (1998–2007) producing a significantly negative trend (− 1.5 ± 0.2% year− 1) and the recent time period (2008–2013) displaying a flat slope (− 0.3 ± 0.1% year− 1, not significant). The observed shift to more positive or less negative trends in Hg wet deposition primarily seen in the Central-Western regions is consistent with the effects of rising Hg emissions from regions outside the U.S. and Canada and the influence of long-range transport in the free troposphere.

  10. Characterisation of nutrients wet deposition under influence of Saharan dust at Puerto-Rico in Caribbean Sea

    Science.gov (United States)

    Desboeufs, Karine; Formenti, Paola; Triquet, Sylvain; Laurent, Benoit; Denjean, Cyrielle; Gutteriez-Moreno, Ian E.; Mayol-Bracero, Olga L.

    2015-04-01

    Large quantities of African dust are carried across the North Atlantic toward the Caribbean every summer by Trade Winds. Atmospheric deposition of dust aerosols, and in particular wet deposition, is widely acknowledged to be the major delivery pathway for nutrients to ocean ecosystems, as iron, phosphorus and various nitrogen species. The deposition of this dustis so known to have an important impact on biogeochemical processes in the Tropical and Western Atlantic Ocean and Caribbean including Puerto-Rico. However, very few data exists on the chemical composition in nutrients in dusty rain in this region. In the framework of the Dust-ATTAcK project, rainwater was collected at the natural reserve of Cape San Juan (CSJ) (18.38°N, 65.62°W) in Puerto-Ricobetween 20 June 2012 and 12 July 2012 during thedusty period. A total of 7 rainwater events were sampled during various dust plumes. Complementary chemical analyses on aerosols in suspension was also determined during the campaign. The results on dust composition showed that no mixing with anthropogenic material was observed, confirming dust aerosols were the major particles incorporated in rain samples. The partitioning between soluble and particulate nutrients in rain samples showed that phosphorous solubility ranged from 30 and 80%. The average Fe solubility was around 0.5%, in agreement with Fe solubility observed in rains collected in Niger during African monsoon. That means that the high solubility measurements previously observed in Caribbean was probably due to an anthropogenic influence. Atmospheric wet deposition fluxes of soluble and total nutrients (N, P, Si, Fe, Co, Cu, Mn, Ni, Zn) to Caribbean Sea were determined. Atmospheric P and N inputs were strongly depleted relative to the stoichiometry of phytoplankton Fe, N, P and Si requirements.The nitrogen speciation was also determined and showed the predominance of ammonium form. 3-D modeling was used to estimate the spatial extend of these fluxes over the

  11. Long term precipitation chemistry and wet deposition in a remote dry savanna site in Africa (Niger

    Directory of Open Access Journals (Sweden)

    C. Galy-Lacaux

    2009-03-01

    , the total mean wet deposition flux in the Sahelian region is of 60.1 mmol.m−2.yr−1 ±25%. Finally, Banizoumbou measurements are compared to other long-term measurements of precipitation chemistry in the wet savanna of Lamto (Côte d'Ivoire and in the forested zone of Zoétélé (Cameroon. The total chemical loading presents a maximum in the dry savanna and a minimum in the forest (from 143.7, 100.2 to 86.6 μeq.l−1, associated with the gradient of terrigeneous sources. The wet deposition fluxes present an opposite trend, with 60.0 mmol.m−2.yr−1 in Banizoumbou, 108.6 mmol.m−2.yr−1 in Lamto and 162.9 mmol.m−2.yr−1 in Zoétélé, controlled by rainfall gradient along the ecosystems transect.

  12. Silver deposition on chemically treated carbon monolith

    Directory of Open Access Journals (Sweden)

    Jovanović Zoran M.

    2009-01-01

    Full Text Available Carbon monolith was treated with HNO3, KOH and H2O2. Effects of these treatments on the surface functional groups and on the amount of silver deposited on the CM surface were studied by temperature programmed desorption (TPD and atomic absorption spectrometry (AAS. As a result of chemical treatment there was an increase in the amount of surface oxygen complexes. The increase in the amount of silver deposit is proportional to the amount of surface groups that produce CO under decomposition. However, the high amount of CO groups, decomposing above 600°C, induces the smaller Ag crystallite size. Therefore, the high temperature CO evolving oxides are, most likely, the initial centers for Ag deposition.

  13. Determination of electroless deposition by chemical nickeling

    Directory of Open Access Journals (Sweden)

    M. Badida

    2013-07-01

    Full Text Available Increasing of technical level and reliability of machine products in compliance with the economical and ecological terms belongs to the main trends of the industrial development. During the utilisation of these products there arise their each other contacts and the interaction with the environment. That is the reason for their surface degradation by wear effect, corrosion and other influences. The chemical nickel-plating allows autocatalytic deposition of nickel from water solutions in the form of coherent, technically very profitable coating without usage of external source of electric current. The research was aimed at evaluating the surface changes after chemical nickel-plating at various changes of technological parameters.

  14. Comparison of snowpack and winter wet-deposition chemistry in the Rocky Mountains, USA: implications for winter dry deposition

    Science.gov (United States)

    Clow, David W.; Ingersoll, George P.; Mast, M. Alisa; Turk, John T.; Campbell, Donald H.

    Depth-integrated snowpack chemistry was measured just prior to maximum snowpack depth during the winters of 1992-1999 at 12 sites co-located with National Atmospheric Deposition Program/National Trend Network (NADP/NTN) sites in the central and southern Rocky Mountains, USA. Winter volume-weighted mean wet-deposition concentrations were calculated for the NADP/NTN sites, and the data were compared to snowpack concentrations using the paired t-test and the Wilcoxon signed-rank test. No statistically significant differences were indicated in concentrations of SO 42- or NO 3- ( p>0.1). Small, but statistically significant differences ( p⩽0.03) were indicated for all other solutes analyzed. Differences were largest for Ca 2+ concentrations, which on average were 2.3 μeq l -1 (43%) higher in the snowpack than in winter NADP/NTN samples. Eolian carbonate dust appeared to influence snowpack chemistry through both wet and dry deposition, and the effect increased from north to south. Dry deposition of eolian carbonates was estimated to have neutralized an average of 6.9 μeq l -1 and a maximum of 12 μeq l -1 of snowpack acidity at the southernmost sites. The good agreement between snowpack and winter NADP/NTN SO 42- and NO 3- concentrations indicates that for those solutes the two data sets can be combined to increase data density in high-elevation areas, where few NADP/NTN sites exist. This combination of data sets will allow for better estimates of atmospheric deposition of SO 42- and NO 3- across the Rocky Mountain region.

  15. Advanced deposition model for thermal activated chemical vapor deposition

    Science.gov (United States)

    Cai, Dang

    Thermal Activated Chemical Vapor Deposition (TACVD) is defined as the formation of a stable solid product on a heated substrate surface from chemical reactions and/or dissociation of gaseous reactants in an activated environment. It has become an essential process for producing solid film, bulk material, coating, fibers, powders and monolithic components. Global market of CVD products has reached multi billions dollars for each year. In the recent years CVD process has been extensively used to manufacture semiconductors and other electronic components such as polysilicon, AlN and GaN. Extensive research effort has been directed to improve deposition quality and throughput. To obtain fast and high quality deposition, operational conditions such as temperature, pressure, fluid velocity and species concentration and geometry conditions such as source-substrate distance need to be well controlled in a CVD system. This thesis will focus on design of CVD processes through understanding the transport and reaction phenomena in the growth reactor. Since the in situ monitor is almost impossible for CVD reactor, many industrial resources have been expended to determine the optimum design by semi-empirical methods and trial-and-error procedures. This approach has allowed the achievement of improvements in the deposition sequence, but begins to show its limitations, as this method cannot always fulfill the more and more stringent specifications of the industry. To resolve this problem, numerical simulation is widely used in studying the growth techniques. The difficulty of numerical simulation of TACVD crystal growth process lies in the simulation of gas phase and surface reactions, especially the latter one, due to the fact that very limited kinetic information is available in the open literature. In this thesis, an advanced deposition model was developed to study the multi-component fluid flow, homogeneous gas phase reactions inside the reactor chamber, heterogeneous surface

  16. Chemical deposition methods using supercritical fluid solutions

    Science.gov (United States)

    Sievers, Robert E.; Hansen, Brian N.

    1990-01-01

    A method for depositing a film of a desired material on a substrate comprises dissolving at least one reagent in a supercritical fluid comprising at least one solvent. Either the reagent is capable of reacting with or is a precursor of a compound capable of reacting with the solvent to form the desired product, or at least one additional reagent is included in the supercritical solution and is capable of reacting with or is a precursor of a compound capable of reacting with the first reagent or with a compound derived from the first reagent to form the desired material. The supercritical solution is expanded to produce a vapor or aerosol and a chemical reaction is induced in the vapor or aerosol so that a film of the desired material resulting from the chemical reaction is deposited on the substrate surface. In an alternate embodiment, the supercritical solution containing at least one reagent is expanded to produce a vapor or aerosol which is then mixed with a gas containing at least one additional reagent. A chemical reaction is induced in the resulting mixture so that a film of the desired material is deposited.

  17. 3D Numerical Modelling of Transport, Deposition and Resuspension of Highway Deposited Sediments in Wet Detention Ponds

    DEFF Research Database (Denmark)

    Bentzen, Thomas Ruby

    2009-01-01

    concrete channel with width of 0.8 m and a water depth of approximately 0.8 m and in circular flume experiments in order to reproduce near-bed specific processes such as resuspension and consolidation. With good agreement with measurements, modelling of hydrodynamics, transport of dissolved pollutants...... and particles in wet detention ponds is possible with application of a three dimensional RANS model and the advection/dispersion equation taken physical phenomena like wind, waves, deposition, erosion and consolidation of the bottom sediment into account....

  18. Characterizations of wet mercury deposition on a remote high-elevation site in the southeastern Tibetan Plateau

    International Nuclear Information System (INIS)

    Huang, Jie; Kang, Shichang; Zhang, Qianggong; Guo, Junming; Sillanpää, Mika; Wang, Yongjie; Sun, Shiwei

    2015-01-01

    Accurate measurements of wet mercury (Hg) deposition are critically important for the assessment of ecological responses to pollutant loading. The Hg in wet deposition was measured over a 3-year period in the southeastern Tibetan Plateau. The volume-weighted mean (VWM) total Hg (Hg_T) concentration was somewhat lower than those reported in other regions of the Tibetan Plateau, but the VWM methyl-Hg concentration and deposition flux were among the highest globally reported values. The VWM Hg_T concentration was higher in non-monsoon season than in monsoon season, and wet Hg_T deposition was dominated by the precipitation amount rather than the scavenging of atmospheric Hg by precipitation. The dominant Hg species in precipitation was mainly in the form of dissolved Hg, which indicates the pivotal role of reactive gaseous Hg within-cloud scavenging to wet Hg deposition. Moreover, an increasing trend in precipitation Hg concentrations was synchronous with the recent economic development in South Asia. - Highlights: • The lowest Hg_T concentration in precipitation was found at Southeast Tibet Station. • MeHg concentration and wet deposition flux were among the highest at our study site. • Hg_D dominated the concentration and flux of Hg_T in wet Hg deposition. • A long-term increasing trend in the Hg_T concentration was found at our study site. - An increasing trend in the precipitation Hg concentrations was synchronous with the recent economic development in South Asia.

  19. Sensitivity study of the wet deposition schemes in the modelling of the Fukushima accident.

    Science.gov (United States)

    Quérel, Arnaud; Quélo, Denis; Roustan, Yelva; Mathieu, Anne; Kajino, Mizuo; Sekiyama, Thomas; Adachi, Kouji; Didier, Damien; Igarashi, Yasuhito

    2016-04-01

    The Fukushima-Daiichi release of radioactivity is a relevant event to study the atmospheric dispersion modelling of radionuclides. Actually, the atmospheric deposition onto the ground may be studied through the map of measured Cs-137 established consecutively to the accident. The limits of detection were low enough to make the measurements possible as far as 250km from the nuclear power plant. This large scale deposition has been modelled with the Eulerian model ldX. However, several weeks of emissions in multiple weather conditions make it a real challenge. Besides, these measurements are accumulated deposition of Cs-137 over the whole period and do not inform of deposition mechanisms involved: in-cloud, below-cloud, dry deposition. A comprehensive sensitivity analysis is performed in order to understand wet deposition mechanisms. It has been shown in a previous study (Quérel et al, 2016) that the choice of the wet deposition scheme has a strong impact on the assessment of the deposition patterns. Nevertheless, a "best" scheme could not be highlighted as it depends on the selected criteria: the ranking differs according to the statistical indicators considered (correlation, figure of merit in space and factor 2). A possibility to explain the difficulty to discriminate between several schemes was the uncertainties in the modelling, resulting from the meteorological data for instance. Since the move of the plume is not properly modelled, the deposition processes are applied with an inaccurate activity in the air. In the framework of the SAKURA project, an MRI-IRSN collaboration, new meteorological fields at higher resolution (Sekiyama et al., 2013) were provided and allows to reconsider the previous study. An updated study including these new meteorology data is presented. In addition, a focus on several releases causing deposition in located areas during known period was done. This helps to better understand the mechanisms of deposition involved following the

  20. Standard test method for determining atmospheric chloride deposition rate by wet candle method

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2002-01-01

    1.1 This test method covers a wet candle device and its use in measuring atmospheric chloride deposition (amount of chloride salts deposited from the atmosphere on a given area per unit time). 1.2 Data on atmospheric chloride deposition can be useful in classifying the corrosivity of a specific area, such as an atmospheric test site. Caution must be exercised, however, to take into consideration the season because airborne chlorides vary widely between seasons. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  1. Deceleration-driven wetting transition of "gently" deposited drops on textured hydrophobic surfaces

    Science.gov (United States)

    Varanasi, Kripa; Kwon, Hyukmin; Paxson, Adam; Patankar, Neelesh

    2010-11-01

    Many applications of rough superhydrophobic surfaces rely on the presence of droplets in a Cassie state on the substrates. A well established understanding is that if sessile droplets are smaller than a critical size, then the large Laplace pressure induces wetting transition from a Cassie to a Wenzel state, i.e., the liquid impales the roughness grooves. Thus, larger droplets are expected to remain in the Cassie state. In this work we report a surprising wetting transition where even a "gentle" deposition of droplets on rough substrates lead to the transition of larger droplets to the Wenzel state. A hitherto unknown mechanism based on rapid deceleration is identified. It is found that modest amount of energy, during the deposition process, is channeled through rapid deceleration into high water hammer pressure which induces wetting transition. A new "phase" diagram is reported which shows that both large and small droplets can transition to Wenzel states due to the deceleration and Laplace mechanisms, respectively. This novel insight reveals for the first time that the attainment of a Cassie state is more restrictive than previous criteria based on the Laplace pressure transition mechanism.

  2. Wet and dry deposition and resuspension of AFCT/TFCT fuel processing radionuclides. Final report

    International Nuclear Information System (INIS)

    Slinn, W.G.N.; Katen, P.C.; Wolf, M.A.; Loveland, W.D.; Radke, L.F.; Miller, E.L.; Ghannam, L.J.; Reynolds, B.W.; Vickers, D.

    1979-09-01

    After short summary and introductory chapters, Chapter IV contains a critical analysis of available parameterizations for resuspension and for wet and dry removal processes and recommends interim parameterizations for use in radiation dose calculations. Chapter V describes methods and experimental results from field studies of in-cloud vs below-cloud scavenging, precipitation efficiency, and modifications of aerosols by clouds. In Chapter VI are contained descriptions of methods and results from four different approaches to the problem of measuring the dry deposition velocities of submicron aerosol particles depositing on vegetation. Chapter VII describes experimental results from a study of resuspension and weathering of tracer aerosol particles deposited on soil, grass and gravel; typical resuspension rates were found to be of the order of 10 -8 s -1 and it is recommended that the concept of weathering be reassessed. In Chapter VIII, National Weather Service data are used to obtain Lagrangian statistics for use in a regional-scale study of wet and dry removal. Chapter IX develops new concepts in reservoir models for application at regional to global scales. In the final chapter are some comments about the results found in this study and recommendations for future research

  3. Chemical Vapour Deposition of Large Area Graphene

    DEFF Research Database (Denmark)

    Larsen, Martin Benjamin Barbour Spanget

    Chemical Vapor Deposition (CVD) is a viable technique for fabrication of large areas of graphene. CVD fabrication is the most prominent and common way of fabricating graphene in industry. In this thesis I have attempted to optimize a growth recipe and catalyst layer for CVD fabrication of uniform......, single layer, and high carrier mobility large area graphene. The main goals of this work are; (1) explore the graphene growth mechanics in a low pressure cold-wall CVD system on a copper substrate, and (2) optimize the process of growing high quality graphene in terms of carrier mobility, and crystal...... structure. Optimization of a process for graphene growth on commercially available copper foil is limited by the number of aluminium oxide particles on the surface of the catalyst. By replacing the copper foil with a thin deposited copper film on a SiO2/Si or c-plane sapphire wafer the particles can...

  4. Contributions of wastewater, runoff and sewer deposit erosion to wet weather pollutant loads in combined sewer systems.

    Science.gov (United States)

    Gasperi, J; Gromaire, M C; Kafi, M; Moilleron, R; Chebbo, G

    2010-12-01

    An observatory of urban pollutants was created in Paris for the purpose of assessing the dynamics of wastewater and wet weather flow (WW and WWF) pollutant loads within combined sewers. This observatory is composed of six urban catchments, covering land areas ranging in size from 42 ha to 2581 ha. For a wide array of parameters including total suspended solids (TSS), chemical and biochemical oxygen demand (COD and BOD(5)), total organic carbon (TOC), total Kjeldahl nitrogen (TKN), heavy metals (Cu and Zn) and polycyclic aromatic hydrocarbons (PAHs), this article is intended to evaluate the contributions of wastewater, runoff and in-sewer processes to WWF pollutant loads through the use of an entry-exit mass balance approach. To achieve this objective, a total of 16 rain events were sampled on these sites between May 2003 and February 2006. This study has confirmed that at the considered catchment scale (i.e. from 42 ha to 2581 ha) the production and transfer processes associated with WWF pollutant loads do not vary with basin scale. Entry-exit chemical mass balances over all catchments and for a large number of rain events indicate that wastewater constitutes the main source of organic and nitrogenous pollution, while runoff is the predominant source of Zn. For Cu, PAHs and TSS, the calculation underscores the major role played by in-sewer processes, specifically by sediment erosion, as a source of WWF pollution. A significant loss of dissolved metals was also observed during their transfer within the sewer network, likely as a consequence of the adsorption of dissolved metals on TSS and/or on sewer deposits. Moreover, the nature of eroded particles was examined and compared to the various sewer deposits. This comparison has highlighted that such particles exhibit similar organic and PAH contents to those measured in the organic layer, thus suggesting that the deposit eroded during a wet weather period is organic and of a nature comparable to the organic layer

  5. Conditioning of Si-interfaces by wet-chemical oxidation: Electronic interface properties study by surface photovoltage measurements

    Energy Technology Data Exchange (ETDEWEB)

    Angermann, Heike, E-mail: angermann@helmholtz-berlin.de

    2014-09-01

    Highlights: • Determination of electronic interface properties by contact-less surface photovoltage (SPV) technique. • Systematic correlations of substrate morphology and surface electronic properties. • Optimization of surface pre-treatment for flat, saw damage etched, and textured Si solar cell substrates. • Ultra-thin passivating Si oxide layers with low densities of rechargeable states by wet-chemical oxidation and subsequent annealing. • Environmentally acceptable processes, utilizing hot water, diluted HCl, or ozone low cost alternative to current approaches with concentrated chemicals. • The effect of optimized wet-chemical pre-treatments can be preserved during subsequent layer deposition. - Abstract: The field-modulated surface photovoltage (SPV) method, a very surface sensitive technique, was utilized to determine electronic interface properties on wet-chemically oxidized and etched silicon (Si) interfaces. The influence of preparation-induced surface micro-roughness and un-stoichiometric oxides on the resulting the surface charge, energetic distribution D{sub it}(E), and density D{sub it,min} of rechargeable states was studied by simultaneous, spectroscopic ellipsometry (SE) measurements on polished Si(111) and Si(100) substrates. Based on previous findings and new research, a study of conventional and newly developed wet-chemical oxidation methods was established, correlating the interactions between involved oxidizing and etching solutions and the initial substrate morphology to the final surface conditioning. It is shown, which sequences of wet-chemical oxidation and oxide removal, have to be combined in order to achieve atomically smooth, hydrogen terminated surfaces, as well as ultra-thin oxide layers with low densities of rechargeable states on flat, saw damage etched, and textured Si substrates, as commonly applied in silicon device and solar cell manufacturing. These conventional strategies for wet-chemical pre-treatment are mainly

  6. Influence of radioactive contamination to agricultural products due to dry and wet deposition processes during a nuclear emergency

    International Nuclear Information System (INIS)

    Hwang, Won Tae; Kim, Eun Han; Suh, Kyung Suk; Han, Moon Hee; Choi, Yong Ho; Lee, Chang Woo

    2002-01-01

    Combined with deposition model onto the ground of radionuclides, the influence of radioactive contamination to agricultural products was analyzed due to wet deposition as well as dry deposition from radioactive air concentration during a nuclear emergency. The previous dynamic food chain model, in which initial input parameter is only radionuclide concentrations on the ground, was improved for the evaluating of radioactive contamination to agricultural products from either radionuclide concentrations in air or radionuclide concentrations on the ground. As the results, in case of deposition onto the ground, wet deposition was more dominant process than dry deposition. While the contamination levels of agricultural products were dependent on the a variety of factors such as radionuclides and rainfall rate. It means that the contamination levels of agricultural products are determined from which is more dominant process between deposition on the ground and interception onto agricultural plants

  7. Characterisation of silicon carbide films deposited by plasma-enhanced chemical vapour deposition

    International Nuclear Information System (INIS)

    Iliescu, Ciprian; Chen Bangtao; Wei Jiashen; Pang, A.J.

    2008-01-01

    The paper presents a characterisation of amorphous silicon carbide films deposited in plasma-enhanced chemical vapour deposition (PECVD) reactors for MEMS applications. The main parameter was optimised in order to achieve a low stress and high deposition rate. We noticed that the high frequency mode (13.56 MHz) gives a low stress value which can be tuned from tensile to compressive by selecting the correct power. The low frequency mode (380 kHz) generates high compressive stress (around 500 MPa) due to ion bombardment and, as a result, densification of the layer achieved. Temperature can decrease the compressive value of the stress (due to annealing effect). A low etching rate of the amorphous silicon carbide layer was noticed for wet etching in KOH 30% at 80 o C (around 13 A/min) while in HF 49% the layer is practically inert. A very slow etching rate of amorphous silicon carbide layer in XeF 2 -7 A/min- was observed. The paper presents an example of this application: PECVD-amorphous silicon carbide cantilevers fabricated using surface micromachining by dry-released technique in XeF 2

  8. Wet nitrogen deposition across the urban-intensive agricultural-rural transect of a small urban area in southwest China.

    Science.gov (United States)

    Deng, Ouping; Zhang, Shirong; Deng, Liangji; Zhang, Chunlong; Fei, Jianbo

    2018-03-01

    Understanding of the spatial and temporal variation of the flux of atmospheric nitrogen (N) deposition is essential for assessment of its impact on ecosystems. However, little attention has been paid to the variability of N deposition across urban-intensive agricultural-rural transects. A continuous 2-year observational study (from January 2015 to December 2016) was conducted to determine wet N deposition across the urban-intensive agricultural-rural transect of a small urban area in southwest China. Significantly spatial and temporal variations were found in the research area. Along the urban-intensive agricultural-rural transect, the TN and NH 4 + -N deposition first increased and then decreased, and the NO 3 - -N and dissolved organic N (DON) deposition decreased continuously. Wet N deposition was mainly affected by the districts of agro-facilities, roads and build up lands. Wet NH 4 + -N deposition had non-seasonal emission sources including industrial emissions and urban excretory wastes in urban districts and seasonal emission sources such as fertilizer and manure volatilization in the other districts. However, wet NO 3 - -N deposition had seasonal emission sources such as industrial emissions and fireworks in urban district and non-seasonal emission sources such as transportation in the other districts. Deposition of DON was likely to have had similar sources to NO 3 - -N deposition in rural district, and high-temperature-dependent sources in urban and intensive agricultural districts. Considering the annual wet TN deposition in the intensive agricultural district was about 11.1% of the annual N fertilizer input, N fertilizer rates of crops should be reduced in this region to avoid the excessive application, and the risk of N emissions to the environment.

  9. Wet chemical synthesis of nickel supported on alumina catalysts

    International Nuclear Information System (INIS)

    Freire, Ranny Rodrigues; Costa, Talita Kenya Oliveira; Morais, Ana Carla da Fonseca Ferreira; Costa, Ana Cristina Figueiredo de Melo; Freitas, Normanda Lino de

    2016-01-01

    Heterogenic catalysts are those found to be in a different phase on the reaction when compared to the reactants and products. Preferred when compared to homogeneous catalysts due to the easiness on which the separation is processed. The objective of this study is to obtain and characterize Alumina based catalysts impregnated with Nickel (Al_2O_3), by wet impregnation. The alumina was synthesized by combustion reaction. Before and after the impregnation the catalysts were characterized by X-ray diffraction (XRD), granulometric analysis, the textural analysis will be held by nitrogen adsorption (BET), energy-dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM). The results show a presence of a stable crystalline phase of Al2O3 in all the studied samples and after the impregnation the second phase formed was of NiO and NiAl_2O_4. The Al_2O_3 e Ni/Al_2O_3 catalysts resulted in clusters with a medium diameter of 18.9 and 14.2 μm, respectively. The catalysts show a medium-pore characteristic (medium pore diameter between 2 and 50 nm), the superficial area to Al_2O_3 and Ni/Al_2O_3 catalysts were 8.69 m"2/g and 5.56 m"2/g, respectively. (author)

  10. Tungsten Deposition on Graphite using Plasma Enhanced Chemical Vapour Deposition

    International Nuclear Information System (INIS)

    Sharma, Uttam; Chauhan, Sachin S; Sharma, Jayshree; Sanyasi, A K; Ghosh, J; Choudhary, K K; Ghosh, S K

    2016-01-01

    The tokamak concept is the frontrunner for achieving controlled thermonuclear reaction on earth, an environment friendly way to solve future energy crisis. Although much progress has been made in controlling the heated fusion plasmas (temperature ∼ 150 million degrees) in tokamaks, technological issues related to plasma wall interaction topic still need focused attention. In future, reactor grade tokamak operational scenarios, the reactor wall and target plates are expected to experience a heat load of 10 MW/m 2 and even more during the unfortunate events of ELM's and disruptions. Tungsten remains a suitable choice for the wall and target plates. It can withstand high temperatures, its ductile to brittle temperature is fairly low and it has low sputtering yield and low fuel retention capabilities. However, it is difficult to machine tungsten and hence usages of tungsten coated surfaces are mostly desirable. To produce tungsten coated graphite tiles for the above-mentioned purpose, a coating reactor has been designed, developed and made operational at the SVITS, Indore. Tungsten coating on graphite has been attempted and successfully carried out by using radio frequency induced plasma enhanced chemical vapour deposition (rf -PECVD) for the first time in India. Tungsten hexa-fluoride has been used as a pre-cursor gas. Energy Dispersive X-ray spectroscopy (EDS) clearly showed the presence of tungsten coating on the graphite samples. This paper presents the details of successful operation and achievement of tungsten coating in the reactor at SVITS. (paper)

  11. Investigation on structural and optical properties of ZnO film prepared by simple wet chemical method

    Science.gov (United States)

    Sholehah, Amalia; Mulyadi, Rendi; Haryono, Didied; Muttakin, Imamul; Rusbana, Tb Bahtiar; Mardiyanto

    2018-04-01

    ZnO thin layer has a broad potential application in electronic and optoelectronic devices. In this study, vertically align ZnO layers were deposited on ITO glass using wet chemistry method. The seed layers were prepared using electrodeposition technique at 3°C. The growing process was carried out using chemical bath deposition at 90°C. To improve the structural properties, two different hydrothermal treatment variations were applied separately. From the experiment, it is shown that the hydrothermal process using N2 gas has given the best result, with average diameter, crystallite size, and band-gap energy of 68.83 nm; 56.37 nm; and 3.16 eV, respectively.

  12. Characterization of wet and dry deposition in the downwind of industrial sources in a dry tropical area.

    Science.gov (United States)

    Singh, R K; Agrawal, M

    2001-12-19

    An atmospheric deposition study was conducted in the downwind of Shaktinagar Thermal Power Plant (STPP), Renusagar Thermal Power Plant (RTPP), and Anpara Thermal Power Plant (ATPP), at Singrauli region, Uttar Pradesh (UP), India to characterize dry and wet deposition in relation to different pollution loading. During the study period, dry and wet depositions and levels of gaseous pollutants (SO2 and NO2) were estimated across the sites. Dry deposition was collected on a monthly basis and wet deposition on an event basis. Depositions were analyzed for pH, nitrate (NO3-), ammonium (NH4+), and sulphate (SO4(2-)) contents. Dry deposition rate both collected as clearfall and throughfall varied between 0.15 to 2.28 and 0.33 to 3.48 g m(-2) day(-1), respectively, at control and maximally polluted sites. The pH of dry deposition varied from 5.81 to 6.89 during winter and 6.09 to 7.02 during summer across the sites. During the rainy season, the mean pH of clear wet deposition varied from 6.56 to 7.04 and throughfall varied from 6.81 to 7.22. The concentrations of NO2 and SO2 pollutants were highest during the winter season. Mean SO2 concentrations varied from 18 to 75 g m(-3) at control and differently polluted sites during the winter season. The variation in NO2 concentrations did not show a pattern similar to that of SO2. The highest NO2 concentration during the winter season was 50 g m(-3), observed near RTPP. NO2 concentration did not show much variation among different sites, suggesting that the sources of NO2 emission are evenly distributed along the sites. The concentrations of NH4+, NO3-, and SO4(2-) ions in dry deposition were found to be higher in summer as compared to the winter season. In dry deposition (clearfall) the concentrations of NH4+, NO3-, and SO4(2-) varied from 0.13 to 1.0, 0.81 to 1.95, and 0.82 to 3.27 mg l(-1), respectively, during winter. In wet deposition (clearfall), the above varied from 0.14 to 0.74, 0.81 to 1.82, and 0.67 to 2.70 mg l(-1

  13. Chemical composition of wet precipitation in Ibadan, Nigeria

    Directory of Open Access Journals (Sweden)

    P.C. Onianwa

    2002-12-01

    Full Text Available Rainwater samples were collected for four two-weekly periods at nine sampling points in the city of Ibadan, Nigeria, during May-July, 1999, and analysed for pH, sulphate, nitrate, chloride, phosphate, sodium, potassium, calcium, and magnesium. The rainwater was predominantly neutral with pH values ranging between 5.8 and 7.0, and averaging 6.6 plus or minus 0.3. Average concentrations (μeq/L for all the sampling points and sampling periods were: SO42- (46 plus or minus 22, NO3- (1.6 plus or minus 0.3, Cl- (11 plus or minus 13, PO43- (3.2 plus or minus 1.8, Na (11.7 plus or minus 7.9, K (5.6 plus or minus 4.4, Ca (30 plus or minus 26, and Mg (1.2 plus or minus 8.8. Concentrations of the various ions in the rainwater decreased slightly with the progress of the sampling period. The deposition flux (kg km-2 month-1 was estimated as: SO42- (390, NO3- (16.8, Cl- (67.6, PO43- (17.5, Na (46.6, K (37.9, Ca (104, and Mg (21.5.

  14. WetA bridges cellular and chemical development in Aspergillus flavus.

    Directory of Open Access Journals (Sweden)

    Ming-Yueh Wu

    Full Text Available Bridging cellular reproduction and survival is essential for all life forms. Aspergillus fungi primarily reproduce by forming asexual spores called conidia, whose formation and maturation is governed by the central genetic regulatory circuit BrlA→AbaA→WetA. Here, we report that WetA is a multi-functional regulator that couples spore differentiation and survival, and governs proper chemical development in Aspergillus flavus. The deletion of wetA results in the formation of conidia with defective cell walls and no intra-cellular trehalose, leading to reduced stress tolerance, a rapid loss of viability, and disintegration of spores. WetA is also required for normal vegetative growth, hyphal branching, and production of aflatoxins. Targeted and genome-wide expression analyses reveal that WetA exerts feedback control of brlA and that 5,700 genes show altered mRNA levels in the mutant conidia. Functional category analyses of differentially expressed genes in ΔwetA RNA-seq data indicate that WetA contributes to spore integrity and maturity by properly regulating the metabolic pathways of trehalose, chitin, α-(1,3-glucan, β-(1,3-glucan, melanin, hydrophobins, and secondary metabolism more generally. Moreover, 160 genes predicted to encode transcription factors are differentially expressed by the absence of wetA, suggesting that WetA may play a global regulatory role in conidial development. Collectively, we present a comprehensive model for developmental control that bridges spore differentiation and survival in A. flavus.

  15. Seasonal and annual variations and regional characteristics of wet and dry deposition amounts in East Asian region

    Science.gov (United States)

    Sato, K.; Tsuyoshi, O.; Endo, T.; Yagoh, H.; Matsuda, K.

    2011-12-01

    Emission of sulfur and nitrogen compounds in Asian region has been remarkably increased with recent rapid economical growth (Ohara et al., 2007). To appropriately assess the influence of air pollutants on the ecosystem, it is important to quantitatively determine the atmospheric deposition of air pollutants. Here, Seasonal and annual variations and regional characteristics of estimated wet and dry deposition amounts at 27 monitoring sites of Acid Deposition Monitoring Network in East Asia (EANET) from 2003 to 2009 are discussed. Wet deposition sample was collected every 24 hours or 1 week by a wet only sampler. Wet deposition amounts were calculated by the product of the volume-weighted concentrations of ionic species (SO42-, NO3-, and NH4+) in the precipitation and precipitation amount measured by a standard rain gauge at each site. Dry deposition amount was estimated by the inferential method which was originated the model developed by Wesely and Hicks (1977) and modified by Matsuda (2008). The components examined for dry deposition were sulfur compounds (gaseous SO2 and particulate SO42-) and nitrogen compounds (gaseous HNO3 and NH3, particulate NO3- and NH4+). Dry deposition was calculated by the product of the deposition velocity estimated by the inferential method for forest and grass surfaces and the monitored air concentration of each compound. The mean annual dry deposition amounts for sulfur and nitrogen compounds in Japanese sites were in the range of 5-37 and 7-50 mmol m-2 year-1, respectively. The regional characteristics of dry deposition amounts in Japan were similar between sulfur and nitrogen compounds, which showed higher deposition in the Sea of Japan side and the western Japan. The mean annual total (wet + dry) deposition amounts for sulfur and nitrogen compounds in Japanese sites were in the range of 28-77 and 22-130 mmol m-2 year-1, respectively. The contributions of dry deposition to the total deposition amounts were 10-55% and 13-56% for

  16. Zirconia thin film preparation by wet chemical methods at low temperature

    NARCIS (Netherlands)

    Popovici, M.; Graaf, de J.; Verschuuren, M.A.; Graat, P.C.J.; Verheijen, M.A.

    2010-01-01

    In this study the preparation of zirconia thin films with a high refractive index at low temperature is aimed for. Two non-hydrolytic type approaches of wet chemical synthesis are presented. Both by sol–gel and colloid chemistry, highly transmissive, smooth thin films of zirconia cubic and/or

  17. A wet-chemical approach to perovskite and fluorite-type nanoceramics: synthesis and processing

    NARCIS (Netherlands)

    Veldhuis, Sjoerd

    2015-01-01

    In thesis the low-temperature, wet-chemical approach to various functional inorganic oxide materials is described. The main focus of this research is to control the material’s synthesis from liquid precursor to metal oxide powder or thin film; while understanding its formation mechanism. In

  18. Estimating chemical composition of atmospheric deposition fluxes from mineral insoluble particles deposition collected in the western Mediterranean region

    Directory of Open Access Journals (Sweden)

    Y. Fu

    2017-11-01

    Full Text Available In order to measure the mass flux of atmospheric insoluble deposition and to constrain regional models of dust simulation, a network of automatic deposition collectors (CARAGA has been installed throughout the western Mediterranean Basin. Weekly samples of the insoluble fraction of total atmospheric deposition were collected concurrently on filters at five sites including four on western Mediterranean islands (Frioul and Corsica, France; Mallorca, Spain; and Lampedusa, Italy and one in the southern French Alps (Le Casset, and a weighing and ignition protocol was applied in order to quantify their mineral fraction. Atmospheric deposition is both a strong source of nutrients and metals for marine ecosystems in this area. However, there are few data on trace-metal deposition in the literature, since their deposition measurement is difficult to perform. In order to obtain more information from CARAGA atmospheric deposition samples, this study aimed to test their relevance in estimating elemental fluxes in addition to total mass fluxes. The elemental chemical analysis of ashed CARAGA filter samples was based on an acid digestion and an elemental analysis by inductively coupled plasma atomic emission spectroscopy (ICP-AES and mass spectrometry (MS in a clean room. The sampling and analytical protocols were tested to determine the elemental composition for mineral dust tracers (Al, Ca, K, Mg and Ti, nutrients (P and Fe and trace metals (Cd, Co, Cr, Cu, Mn, Ni, V and Zn from simulated wet deposition of dust analogues and traffic soot. The relative mass loss by dissolution in wet deposition was lower than 1 % for Al and Fe, and reached 13 % for P due to its larger solubility in water. For trace metals, this loss represented less than 3 % of the total mass concentration, except for Zn, Cu and Mn for which it could reach 10 %, especially in traffic soot. The chemical contamination during analysis was negligible for all the elements except for Cd

  19. Low-pressure chemical vapor deposition as a tool for deposition of thin film battery materials

    NARCIS (Netherlands)

    Oudenhoven, J.F.M.; Dongen, van T.; Niessen, R.A.H.; Croon, de M.H.J.M.; Notten, P.H.L.

    2009-01-01

    Low Pressure Chemical Vapor Deposition was utilized for the deposition of LiCoO2 cathode materials for all-solid-state thin-film micro-batteries. To obtain insight in the deposition process, the most important process parameters were optimized for the deposition of crystalline electrode films on

  20. Characterizations of wet mercury deposition on a remote high-elevation site in the southeastern Tibetan Plateau.

    Science.gov (United States)

    Huang, Jie; Kang, Shichang; Zhang, Qianggong; Guo, Junming; Sillanpää, Mika; Wang, Yongjie; Sun, Shiwei; Sun, Xuejun; Tripathee, Lekhendra

    2015-11-01

    Accurate measurements of wet mercury (Hg) deposition are critically important for the assessment of ecological responses to pollutant loading. The Hg in wet deposition was measured over a 3-year period in the southeastern Tibetan Plateau. The volume-weighted mean (VWM) total Hg (HgT) concentration was somewhat lower than those reported in other regions of the Tibetan Plateau, but the VWM methyl-Hg concentration and deposition flux were among the highest globally reported values. The VWM HgT concentration was higher in non-monsoon season than in monsoon season, and wet HgT deposition was dominated by the precipitation amount rather than the scavenging of atmospheric Hg by precipitation. The dominant Hg species in precipitation was mainly in the form of dissolved Hg, which indicates the pivotal role of reactive gaseous Hg within-cloud scavenging to wet Hg deposition. Moreover, an increasing trend in precipitation Hg concentrations was synchronous with the recent economic development in South Asia. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Quantitative analysis of precipitation over Fukushima to understand the wet deposition process in March 2011

    Science.gov (United States)

    Yatagai, A.; Onda, Y.; Watanabe, A.

    2012-04-01

    The Great East Japan Earthquake caused a severe accident at the Fukushima-Daiichi nuclear power plant (NPP), leading to the emission of large amounts of radioactive pollutants into the environment. The transport and diffusion of these radioactive pollutants in the atmosphere caused a disaster for residents in and around Fukushima. Studies have sought to understand the transport, diffusion, and deposition process, and to understand the movement of radioactive pollutants through the soil, vegetation, rivers, and groundwater. However, a detailed simulation and understanding of the distribution of radioactive compounds depend on a simulation of precipitation and on the information on the timing of the emission of these radioactive pollutants from the NPP. Past nuclear expansion studies have demonstrated the importance of wet deposition in distributing pollutants. Hence, this study examined the quantitative precipitation pattern in March 2011 using rain-gauge observations and X-band radar data from Fukushima University. We used the AMeDAS rain-gauge network data of 1) the Japan Meteorological Agency (1273 stations in Japan) and 2) the Water Information System (47 stations in Fukushima prefecture) and 3) the rain-gauge data of the Environmental Information Network of NTT Docomo (30 stations in Fukushima) to construct 0.05-degree mesh data using the same method used to create the APHRODITE daily grid precipitation data (Yatagai et al., 2009). Since some AMeDAS data for the coastal region were lost due to the earthquake, the complementary network of 2) and 3) yielded better precipitation estimates. The data clarified that snowfall was observed on the night of Mar 15 into the morning of Mar 16 throughout Fukushima prefecture. This had an important effect on the radioactive contamination pattern in Fukushima prefecture. The precipitation pattern itself does not show one-on-one correspondence with the contamination pattern. While the pollutants transported northeast of the

  2. Ammonia emissions in the United States, European Union, and China derived by high-resolution inversion of ammonium wet deposition data: Interpretation with a new agricultural emissions inventory (MASAGE_NH3)

    Science.gov (United States)

    We use the adjoint of a global 3-D chemical transport model (GEOS-Chem) to optimizeammonia (NH3European Union, and China by inversion of 2005–2008 network data for NH+4 wet deposition fluxes. Optimized emissions are derive...

  3. Wet etching and chemical polishing of InAs/GaSb superlattice photodiodes

    International Nuclear Information System (INIS)

    Chaghi, R; Cervera, C; Aït-Kaci, H; Grech, P; Rodriguez, J B; Christol, P

    2009-01-01

    In this paper, we studied wet chemical etching fabrication of the InAs/GaSb superlattice mesa photodiode for the mid-infrared region. The details of the wet chemical etchants used for the device process are presented. The etching solution is based on orthophosphoric acid (H 3 PO 4 ), citric acid (C 6 H 8 O 7 ) and H 2 O 2 , followed by chemical polishing with the sodium hypochlorite (NaClO) solution and protection with photoresist polymerized. The photodiode performance is evaluated by current–voltage measurements. The zero-bias resistance area product R 0 A above 4 × 10 5 Ω cm 2 at 77 K is reported. The device did not show dark current degradation at 77 K after exposition during 3 weeks to the ambient air

  4. Deposition and early hydrologic evolution of Westwater Canyon wet alluvial-fan system

    International Nuclear Information System (INIS)

    Galloway, W.E.

    1980-01-01

    The Westwater Canyon Member is one of several large, low-gradient alluvial fans that compose the Morrison Formation in the Four Corners area. Morrison fans were deposited by major laterally migrating streams entering a broad basin bounded by highlands to the west and south. The Westwater Canyon sand framework consists of a downfan succession of 1) proximal braided channel, 2) straight bed-load channel, 3) sinuous mixed-load channel, and 4) distributary mixed-load-channel sand bodies. Regional sand distribution and facies patterns are highly digitate and radiate from a point source located northwest of Gallup, New Mexico. Early ground-water flow evolution within the Westwater Canyon fan aquifer system can be inferred by analogy with Quaternary wet-fan deposits and by the interpreted paragenetic sequence of diagenetic features present. Syndepositional flow was controlled by the downfan hydrodynamic gradient and the high horizontal and vertical transmissivity of the sand-rich fan aquifer. Dissolution and transport of soluble humate would be likely in earliest ground water, which was abundant, fresh, and slightly alkaline. With increasing confinement of the aquifer below less permeable tuffaceous Brushy Basin deposits and release of soluble constituents from volcanic ash, flow patterns stabilized, and relatively more saline, uranium-rich ground water permeated the aquifer. Uranium mineralization occurred during this early postdepositional, semiconfined flow phase. Development of overlying Dakota swamps suggests a shallow water table indicative of regional dischare or stagnation. In either event, only limited downward flux of acidic water is recorded by local, bleached, kaolinized zones where the Westwater Canyon directly underlies the Dakota swamps. Subsequent ground-water flow phases have further obscured primary alteration patterns and caused local oxidation and redistribution of uranium

  5. Green wet chemical route to synthesize capped CdSe quantum dots

    Indian Academy of Sciences (India)

    In the present work, we report green synthesis of tartaric acid (TA) and triethanolamine (TEA) capped ... CdSe quantum dots; chemical bath deposition; capping; green chemistry; nanomaterials. 1. .... at high concentration of nanoparticles.

  6. Effects of wet deposition on the abundance and size distribution of black carbon in East Asia

    Science.gov (United States)

    Kondo, Y.; Moteki, N.; Oshima, N.; Ohata, S.; Koike, M.; Shibano, Y.; Takegawa, N.; Kita, K.

    2016-05-01

    An improved understanding of the variations in the mass concentration and size distribution of black carbon (BC) in the free troposphere (FT) over East Asia, where BC emissions are very high, is needed to reliably estimate the radiative forcing of BC in climate models. We measured these parameters and the carbon monoxide (CO) concentration by conducting the Aerosol Radiative Forcing in East Asia (A-FORCE) 2013W aircraft campaign in East Asia in winter 2013 and compared these data with measurements made in the same region in spring 2009. The median BC concentrations in the FT originating from North China (NC) and South China (SC) showed different seasonal variations, which were primarily caused by variations in meteorological conditions. CO concentrations above the background were much higher in SC than in NC in both seasons, suggesting a more active upward transport of CO. In SC, precipitation greatly increased from winter to spring, leading to an increased wet deposition of BC. As a result, the median BC concentration in the FT was highest in SC air in winter. This season and region were optimal for the effective transport of BC from the planetary boundary layer to the FT. The count median diameters of the BC size distributions generally decreased with altitude via wet removal during upward transport. The altitude dependence of the BC size distributions was similar in winter and spring, in accord with the similarity in the BC mixing state. The observed BC concentrations and microphysical properties will be useful for evaluating the performance of climate models.

  7. Hot-wire chemical vapour deposition of carbon nanotubes

    CSIR Research Space (South Africa)

    Cummings, FR

    2006-07-01

    Full Text Available ablation of graphite, carbon-arc discharge and chemical vapour deposition (CVD). However, some of these techniques have been shown to be expensive due to high deposition temperatures and are not easily controllable. Recently hot-wire chemical vapour...

  8. Investigation of the Factors Influencing Volatile Chemical Fate During Steady-state Accretion on Wet-growing Hail

    Science.gov (United States)

    Michael, R. A.; Stuart, A. L.

    2007-12-01

    Phase partitioning during freezing affects the transport and distribution of volatile chemical species in convective clouds. This consequently can have impacts on tropospheric chemistry, air quality, pollutant deposition, and climate change. Here, we discuss the development, evaluation, and application of a mechanistic model for the study and prediction of volatile chemical partitioning during steady-state hailstone growth. The model estimates the fraction of a chemical species retained in a two-phase freezing hailstone. It is based upon mass rate balances over water and solute for accretion under wet-growth conditions. Expressions for the calculation of model components, including the rates of super-cooled drop collection, shedding, evaporation, and hail growth were developed and implemented based on available cloud microphysics literature. Solute fate calculations assume equilibrium partitioning at air-liquid and liquid-ice interfaces. Currently, we are testing the model by performing mass balance calculations, sensitivity analyses, and comparison to available experimental data. Application of the model will improve understanding of the effects of cloud conditions and chemical properties on the fate of dissolved chemical species during hail growth.

  9. Chemical deposits in volcanic caves of Argentina

    Directory of Open Access Journals (Sweden)

    Carlos Benedetto

    1998-01-01

    Full Text Available During the last Conference of the FEALC (Speleological Federation of Latin America and Caribbean Islands which was held in the town of Malargue, Mendoza, in February 1997, two volcanic caves not far from that town were visited and sampled for cave mineral studies. The first cave (Cueva del Tigre opens close to the Llancanelo lake, some 40 kms far from Malargue and it is a classical lava tube. Part of the walls and of the fallen lava blocks are covered by white translucent fibres and grains. The second visited cave is a small tectonic cavity opened on a lava bed some 100 km southward of Malargue. The cave “El Abrigo de el Manzano” is long no more than 10-12 meters with an average width of 3 meters and it hosts several bird nests, the larger of which is characterized by the presence of a relatively thick pale yellow, pale pink flowstone. Small broken or fallen samples of the secondary chemical deposits of both these caves have been collected in order to detect their mineralogical composition. In the present paper the results of the detailed mineralogical analyses carried out on the sampled material are shortly reported. In the Cueva del Tigre lava tube the main detected minerals are Sylvite, Thenardite, Bloedite and Kieserite, all related to the peculiar dry climate of that area. The flowstone of “El Abrigo de el Manzano” consists of a rather complex admixture of several minerals, the large majority of which are phosphates but also sulfates and silicates, not all yet identified. The origin of all these minerals is related to the interaction between bird guano and volcanic rock.

  10. Gas analysis during the chemical vapor deposition of carbon

    International Nuclear Information System (INIS)

    Lieberman, M.L.; Noles, G.T.

    1973-01-01

    Gas chromatographic analyses were performed during the chemical vapor deposition of carbon in both isothermal and thermal gradient systems. Such data offer insight into the gas phase processes which occur during deposition and the interrelations which exist between gas composition, deposition rate, and resultant structure of the deposit. The results support a carbon CVD model presented previously. The application of chromatographic analysis to research, development, and full-scale facilities is shown. (U.S.)

  11. Changes in wetting and energetic properties of glass caused by deposition of different lipid layers

    Energy Technology Data Exchange (ETDEWEB)

    Golabek, Monika [Department of Physical Chemistry - Interfacial Phenomena, Faculty of Chemistry, Maria-Curie Sklodowska University, 20-031 Lublin (Poland); Holysz, Lucyna, E-mail: lucyna.holysz@poczta.umcs.lublin.pl [Department of Physical Chemistry - Interfacial Phenomena, Faculty of Chemistry, Maria-Curie Sklodowska University, 20-031 Lublin (Poland)

    2010-06-15

    An investigation of wetting and energetic properties of different lipid layers deposited on the glass surface was carried out by contact angles measurements and determination of the apparent surface free energy. The topography of the lipid layers was also determined with the help of atomic force microscopy (AFM). Two synthetic phospholipids were chosen for these studies, having the same phosphatidylcholine headgroup bound to the apolar part composed either by two saturated chains (1,2-dipalmitoyl-sn-glycero-3-phospshocholine - DPPC) or two unsaturated chains (1,2-dioleoyl-sn-glycero-3-phosphocholine - DOPC) and one lipid (1,2,3-trihexadecanoyl-sn-glycerol - tripalmitoylglycerol - TPG). The lipid layers, from the 1st to the 5th statistical monolayer, were deposited on the glass surface from chloroform solutions by spreading. The apparent surface free energy of the deposited layers was determined by contact angles measurements (advancing and receding) for three probe liquids (diiodomethane, water, and formamide), and then two concepts of interfacial interactions were applied. In the contact angle hysteresis approach (CAH) the apparent total surface free energy was calculated from the advancing and receding contact angles and surface tension of probe liquids. In the Lifshitz-van der Waals/acid-base approach (LWAB) the total surface free energy was calculated from the determined components of the energy, which were obtained from the advancing contact angles of the probe liquids only. Comparison of the results obtained by two approaches provided more information about the changes in the hydrophobicity/hydrophilicity of the layers depending on the number of monolayers and kind of the lipid deposited on the glass surface. It was found that the most visible changes in the surface free energy took place for the first two statistical monolayers irrespectively of the kind of the lipid used. Additionally, in all cases periodic oscillations from layer-to-layer in the lipid

  12. Influence of wet chemical cleaning on quantum efficiency of GaN photocathode

    International Nuclear Information System (INIS)

    Wang Xiao-Hui; Gao Pin; Wang Hong-Gang; Li Biao; Chang Ben-Kang

    2013-01-01

    GaN samples 1–3 are cleaned by a 2:2:1 solution of sulfuric acid (98%) to hydrogen peroxide (30%) to de-ionized water; hydrochloric acid (37%); or a 4:1 solution of sulfuric acid (98%) to hydrogen peroxide (30%). The samples are activated by Cs/O after the same annealing process. X-ray photoelectron spectroscopy after the different ways of wet chemical cleaning shows: sample 1 has the largest proportion of Ga, N, and O among the three samples, while its C content is the lowest. After activation the quantum efficiency curves show sample 1 has the best photocathode performance. We think the wet chemical cleaning method is a process which will mainly remove C contamination. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  13. Activation of aluminum as an effective reducing agent by pitting corrosion for wet-chemical synthesis.

    Science.gov (United States)

    Li, Wei; Cochell, Thomas; Manthiram, Arumugam

    2013-01-01

    Metallic aluminum (Al) is of interest as a reducing agent because of its low standard reduction potential. However, its surface is invariably covered with a dense aluminum oxide film, which prevents its effective use as a reducing agent in wet-chemical synthesis. Pitting corrosion, known as an undesired reaction destroying Al and is enhanced by anions such as F⁻, Cl⁻, and Br⁻ in aqueous solutions, is applied here for the first time to activate Al as a reducing agent for wet-chemical synthesis of a diverse array of metals and alloys. Specifically, we demonstrate the synthesis of highly dispersed palladium nanoparticles on carbon black with stabilizers and the intermetallic Cu₂Sb/C, which are promising candidates, respectively, for fuel cell catalysts and lithium-ion battery anodes. Atomic hydrogen, an intermediate during the pitting corrosion of Al in protonic solvents (e.g., water and ethylene glycol), is validated as the actual reducing agent.

  14. Sensitivity of the modelled deposition of Caesium-137 from the Fukushima Dai-ichi nuclear power plant to the wet deposition parameterisation in NAME

    International Nuclear Information System (INIS)

    Leadbetter, Susan J.; Hort, Matthew C.; Jones, Andrew R.; Webster, Helen N.; Draxler, Roland R.

    2015-01-01

    This paper describes an investigation into the impact of different meteorological data sets and different wet scavenging coefficients on the model predictions of radionuclide deposits following the accident at the Fukushima Dai-ichi nuclear power plant in March 2011. Three separate operational meteorological data sets, the UK Met Office global meteorology, the ECMWF global meteorology and the Japan Meteorological Agency (JMA) mesoscale meteorology as well as radar rainfall analyses from JMA were all used as inputs to the UK Met Office's dispersion model NAME (the Numerical Atmospheric-dispersion Modelling Environment). The model predictions of Caesium-137 deposits based on these meteorological models all showed good agreement with observations of deposits made in eastern Japan with correlation coefficients ranging from 0.44 to 0.80. Unexpectedly the NAME run using radar rainfall data had a lower correlation coefficient (R = 0.66), when compared to observations, than the run using the JMA mesoscale model rainfall (R = 0.76) or the run using ECMWF met data (R = 0.80). Additionally the impact of modifying the wet scavenging coefficients used in the parameterisation of wet deposition was investigated. The results showed that modifying the scavenging parameters had a similar impact to modifying the driving meteorology on the rank calculated from comparing the modelled and observed deposition

  15. Atmospheric wet deposition of mercury and other trace elements in Pensacola, Florida

    Directory of Open Access Journals (Sweden)

    W. M. Landing

    2010-05-01

    Full Text Available In an effort to understand and quantify the impact of local, regional, and far-distant atmospheric mercury sources to rainfall mercury deposition in the Pensacola, Florida watershed, a program of event-based rainfall sampling was started in late 2004. Modified Aerochem-Metrics wet/dry rainfall samplers were deployed at three sites in the region around the Crist coal-fired power plant and event-based samples were collected continuously for three years. Samples were analyzed for total Hg and a suite of trace elements including Al, As, Ba, Bi, Cd, Ce, Co, Cr, Cs, Cu, Fe, Ga, La, Li, Mg, Mn, Na, Nb, Ni, P, Pb, Sb, Se, Si, Sn, Sr, Th, U, V, and Zn. Nutrients (ammonia and nitrate and major anions (chloride and sulfate were also measured on each sample. Multivariate statistical methods were used to sort these tracers into factors that represent potential source categories contributing to the rainfall chemistry. As, Hg, Sb, Se, Sn, and non sea-salt sulfate were all significantly correlated (R>0.6 with one factor which we interpret as an anthropogenic source term reflecting input from coal combustion throughout the southeastern US. Using ratios of total Hg to volatile elements, we estimate that 22–33% of the rainfall Hg results from coal combustion in the southeastern US with the majority coming from the global background.

  16. Fabrication of high quality GaN nanopillar arrays by dry and wet chemical etching

    OpenAIRE

    Paramanik, Dipak; Motayed, Abhishek; King, Matthew; Ha, Jong-Yoon; Kryluk, Sergi; Davydov, Albert V.; Talin, Alec

    2013-01-01

    We study strain relaxation and surface damage of GaN nanopillar arrays fabricated using inductively coupled plasma (ICP) etching and post etch wet chemical treatment. We controlled the shape and surface damage of such nanopillar structures through selection of etching parameters. We compared different substrate temperatures and different chlorine-based etch chemistries to fabricate high quality GaN nanopillars. Room temperature photoluminescence and Raman scattering measurements were carried ...

  17. Year-round atmospheric wet and dry deposition of nitrogen and phosphorus on water and land surfaces in Nanjing, China.

    Science.gov (United States)

    Sun, Liying; Li, Bo; Ma, Yuchun; Wang, Jinyang; Xiong, Zhengqin

    2013-06-01

    The dry deposition of ammonium, nitrate, and total phosphorus (TP) to both water (DW) and land (DD) surfaces, along with wet deposition, were simultaneously monitored from March 2009 to February 2011 in Nanjing, China. Results showed that wet deposition of total phosphorus was 1.1 kg phosphorus ha (-1)yr(-1), and inorganic nitrogen was 28.7 kg nitrogen ha (-1)yr(-1), with 43% being ammonium nitrogen. Dry deposition of ammonium, nitrate, and total phosphorus, measured by the DW/DD method, was 7.5/2.2 kg nitrogen ha (-1)yr(-1), 6.3/ 4.9 kg nitrogen ha (-1)yr(-1), and 1.9/0.4 kg phosphorus ha (-1)yr(-1), respectively. Significant differences between the DW and DD methods indicated that both methods should be employed simultaneously when analyzing deposition to aquatic and terrestrial ecosystems in watershed areas. The dry deposition of ammonium, nitrate, and total phosphorus contributed 38%, 28%, and 63%, respectively, to the total deposition in the simulated aquatic ecosystem; this has significance for the field of water eutrophication control.

  18. Understanding the chemical vapor deposition of diamond: recent progress

    International Nuclear Information System (INIS)

    Butler, J E; Mankelevich, Y A; Cheesman, A; Ma, Jie; Ashfold, M N R

    2009-01-01

    In this paper we review and provide an overview to the understanding of the chemical vapor deposition (CVD) of diamond materials with a particular focus on the commonly used microwave plasma-activated chemical vapor deposition (MPCVD). The major topics covered are experimental measurements in situ to diamond CVD reactors, and MPCVD in particular, coupled with models of the gas phase chemical and plasma kinetics to provide insight into the distribution of critical chemical species throughout the reactor, followed by a discussion of the surface chemical process involved in diamond growth.

  19. Structural, morphological, wettability and thermal resistance properties of hydro-oleophobic thin films prepared by a wet chemical process

    International Nuclear Information System (INIS)

    Phani, A.R.

    2006-01-01

    The structural properties of fluorine containing polymer compounds make them highly attractive materials for hydro-oleophobic applications. However, most of these exhibit low surface energy and poor adhesion on the substrates. In the present investigation, crack free, smooth and uniform thin films of poly[4,5-difluoro-2,2-bis(trifluoromethyl)-1,3-dioxole] -co-tetrafluoroethylene (TFD-co-TFE) with good adhesion have been deposited by wet chemical spin-coating technique on polished AISI 440C steel substrates. The as-deposited films (xerogel films) have been subjected to annealing for 1 h at different temperatures ranging from 100 to 500 deg. C in an argon atmosphere. The size growth of the nano-hemispheres increased from 8 nm for xerogel film to 28 nm for film annealed at 400 deg. C. It was found that as the annealing temperature increased from 100 to 400 deg. C, nano-hemisphere-like structures were formed, which in turn have shown increase in the water contact angle from 122 deg. to 147 deg. and oil (peanut) contact angle from 85 deg. to 96 deg. No change in the water contact angle (122 deg.) has been observed when the films deposited at room temperature were heated in air from 30 to 80 deg. C as well as exposed to steam for 8 days for 8 h/day indicating thermal stability of the film

  20. Characterization of Wet and Dry Deposition in the Downwind of Industrial Sources in a Dry Tropical Area

    Directory of Open Access Journals (Sweden)

    Raj K. Singh

    2001-01-01

    Full Text Available An atmospheric deposition study was conducted in the downwind of Shaktinagar Thermal Power Plant (STPP, Renusagar Thermal Power Plant (RTPP, and Anpara Thermal Power Plant (ATPP, at Singrauli region, Uttar Pradesh (UP, India to characterize dry and wet deposition in relation to different pollution loading. During the study period, dry and wet depositions and levels of gaseous pollutants (SO2 and NO2 were estimated across the sites. Dry deposition was collected on a monthly basis and wet deposition on an event basis. Depositions were analyzed for pH, nitrate (NO3�, ammonium (NH4+, and sulphate (SO42� contents. Dry deposition rate both collected as clearfall and throughfall varied between 0.15 to 2.28 and 0.33 to 3.48 g m�2 day�1, respectively, at control and maximally polluted sites. The pH of dry deposition varied from 5.81 to 6.89 during winter and 6.09 to 7.02 during summer across the sites. During the rainy season, the mean pH of clear wet deposition varied from 6.56 to 7.04 and throughfall varied from 6.81 to 7.22. The concentrations of NO2 and SO2 pollutants were highest during the winter season. Mean SO2 concentrations varied from 18 to 75 �g m�3 at control and differently polluted sites during the winter season. The variation in NO2 concentrations did not show a pattern similar to that of SO2. The highest NO2 concentration during the winter season was 50 �g m�3, observed near RTPP. NO2 concentration did not show much variation among different sites, suggesting that the sources of NO2 emission are evenly distributed along the sites. The concentrations of NH4+, NO3�, and SO42� ions in dry deposition were found to be higher in summer as compared to the winter season. In dry deposition (clearfall the concentrations of NH4+, NO3�, and SO42� varied from 0.13 to 1.0, 0.81 to 1.95, and 0.82 to 3.27 mg l�1, respectively, during winter. In wet deposition (clearfall, the above varied from 0.14 to 0.74, 0.81 to 1.82, and 0

  1. Nitride-based Schottky diodes and HFETs fabricated by photo-enhanced chemical wet etching

    International Nuclear Information System (INIS)

    Su, Y.K.; Chang, S.J.; Kuan, T.M.; Ko, C.H.; Webb, J.B.; Lan, W.H.; Cherng, Y.T.; Chen, S.C.

    2004-01-01

    Photo-enhanced chemical (PEC) wet etching technology was used to etch GaN and AlGaN epitaxial layers. It was found that the maximum etch rates were 510, 1960, 300, and 0 nm/mm for GaN, Al 0.175 Ga 0.825 N, Al 0.23 Ga 0.77 N, and Al 0.4 Ga 0.6 N, respectively. It was also found that we could achieve a high Al 0.175 Ga 0.825 N to GaN etch rate ratio of 12.6. Nitride-based Schottky diodes and heterostructure field effect transistors (HFETs) were also fabricated by PEC wet etching. It was found that we could achieve a saturated I D larger than 850 mA/mm and a maximum g m about 163 mS/mm from PEC wet etched HFET with a 0.5 μm gate length. Compared with dry etched devices, the leakage currents observed from the PEC wet etched devices were also found to be smaller

  2. Achieving uniform layer deposition by atmospheric-pressure plasma-enhanced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae-Ok [Department of Plasma Engineering, Korea Institute of Machinery & Materials (KIMM), Daejeon 305-343 (Korea, Republic of); Kang, Woo Seok, E-mail: kang@kimm.re.kr [Department of Plasma Engineering, Korea Institute of Machinery & Materials (KIMM), Daejeon 305-343 (Korea, Republic of); Department of Environment & Energy Mechanical Engineering, University of Science & Technology (UST), Daejeon 305-350 (Korea, Republic of); Hur, Min; Lee, Jin Young [Department of Plasma Engineering, Korea Institute of Machinery & Materials (KIMM), Daejeon 305-343 (Korea, Republic of); Song, Young-Hoon [Department of Plasma Engineering, Korea Institute of Machinery & Materials (KIMM), Daejeon 305-343 (Korea, Republic of); Department of Environment & Energy Mechanical Engineering, University of Science & Technology (UST), Daejeon 305-350 (Korea, Republic of)

    2015-12-31

    This work investigates the use of plasma-enhanced chemical vapor deposition under atmospheric pressure for achieving uniform layer formation. Electrical and optical measurements demonstrated that the counterbalance between oxygen and precursors maintained the homogeneous discharge mode, while creating intermediate species for layer deposition. Several steps of the deposition process of the layers, which were processed on a stationary stage, were affected by flow stream and precursor depletion. This study showed that by changing the flow streamlines using substrate stage motion uniform layer deposition under atmospheric pressure can be achieved. - Highlights: • Zirconium oxide was deposited by atmospheric-pressure plasma-enhanced chemical vapor deposition. • Homogeneous plasma was maintained by counterbalancing between discharge gas and precursors. • Several deposition steps were observed affected by the gas flow stream and precursor depletion. • Thin film layer was uniformly grown when the substrate underwent a sweeping motion.

  3. Structural, optical and electrical properties of chemically deposited ...

    Indian Academy of Sciences (India)

    Structural, optical and electrical properties of chemically deposited nonstoichiometric copper ... One of these compounds, CuInSe2, with its optical absorption .... is clear from SEM images that the number of grains goes on increasing with the ...

  4. Chemical solution deposition of functional oxide thin films

    CERN Document Server

    Schneller, Theodor; Kosec, Marija

    2014-01-01

    Chemical Solution Deposition (CSD) is a highly-flexible and inexpensive technique for the fabrication of functional oxide thin films. Featuring nearly 400 illustrations, this text covers all aspects of the technique.

  5. Chemical vapour deposition of thin-film dielectrics

    International Nuclear Information System (INIS)

    Vasilev, Vladislav Yu; Repinsky, Sergei M

    2005-01-01

    Data on the chemical vapour deposition of thin-film dielectrics based on silicon nitride, silicon oxynitride and silicon dioxide and on phosphorus- and boron-containing silicate glasses are generalised. The equipment and layer deposition procedures are described. Attention is focussed on the analysis and discussion of the deposition kinetics and on the kinetic models for film growth. The film growth processes are characterised and data on the key physicochemical properties of thin-film covalent dielectric materials are given.

  6. Electrical Conductivity of CUXS Thin Film Deposited by Chemical ...

    African Journals Online (AJOL)

    Thin films of CuxS have successfully been deposited on glass substrates using the Chemical Bath Deposition (CBD) technique. The films were then investigated for their electrical properties. The results showed that the electrical conductivities of the CuxS films with different molarities (n) of thiourea (Tu), determined using ...

  7. Chemical vapor deposition of nanocrystalline diamond films

    International Nuclear Information System (INIS)

    Vyrovets, I.I.; Gritsyna, V.I.; Dudnik, S.F.; Opalev, O.A.; Reshetnyak, O.M.; Strel'nitskij, V.E.

    2008-01-01

    The brief review of the literature is devoted to synthesis of nanocrystalline diamond films. It is shown that the CVD method is an effective way for deposition of such nanostructures. The basic technological methods that allow limit the size of growing diamond crystallites in the film are studied.

  8. Comparison of chemical solution deposition systems for the fabrication of lead zirconate titanate thin films

    International Nuclear Information System (INIS)

    Lecarpentier, F.; Daglish, M.; Kemmitt, T.

    2001-01-01

    Ferroelectric thin films of lead zirconate titanate Pb(Zr x Ti 1-x )O 3 (PZT) were prepared from five chemical solution deposition (CSD) systems, namely methoxyethanol, citrate, diol, acetic acid and triethanolamine. Physical characteristics of the solutions, processing parameters and physical and electrical properties of the films were used to assess the relative advantages and disadvantages of the different chemical systems. All the CSD systems decomposed to produce single phase perovskite PZT at temperatures above 650 deg C. Thin film deposition was influenced by the specific characteristics of each system such as wetting on the substrate and viscosity. Distinct precursor effects on the thin film crystallinity and electrical performance were revealed. The diol route yielded films with the highest crystallite size, highest permittivity and lowest loss tangent. The relative permittivity exhibited by films made by the other routes were 25% to 35% lower at equivalent thicknesses. Copyright (2001) The Australian Ceramic Society

  9. Mobilization and distribution of lead originating from roof dust and wet deposition in a roof runoff system.

    Science.gov (United States)

    Yu, Jianghua; Yu, Haixia; Huang, Xiaogu

    2015-12-01

    In this research, the mobilization and distribution of lead originating in roof dust and wet deposition were investigated within a roof dust-rooftop-runoff system. The results indicated that lead from roof dust and wet deposition showed different transport dynamics in runoff system and that this process was significantly influenced by the rainfall intensity. Lead present in the roof dust could be easily washed off into the runoff, and nearly 60 % of the total lead content was present in particulate form. Most of the lead from the roof dust was transported during the late period of rainfall; however, the lead concentration was higher for several minutes at the rainfall beginning. Even though some of the lead from wet deposition, simulated with a standard isotope substance, was adsorbed onto adhered roof dust and/or retained on rooftop in runoff system, most of it (50-82 %) remained as dissolved lead in the runoff for rainfall events of varying intensity. Regarding the distribution of lead in the runoff system, the results indicated that it could be carried in the runoff in dissolved and particulate form, be adsorbed to adhered roof dust, or remain on the rooftop because of adsorption to the roof material. Lead from the different sources showed different distribution patterns that were also related to the rainfall intensity. Higher rainfall intensity resulted in a higher proportion of lead in the runoff and a lower proportion of lead remaining on the rooftop.

  10. Stress evaluation of chemical vapor deposited silicon dioxide films

    International Nuclear Information System (INIS)

    Maeda, Masahiko; Itsumi, Manabu

    2002-01-01

    Film stress of chemical vapor deposited silicon dioxide films was evaluated. All of the deposited films show tensile intrinsic stresses. Oxygen partial pressure dependence of the intrinsic stress is very close to that of deposition rate. The intrinsic stress increases with increasing the deposition rate under the same deposition temperature, and decreases with increasing substrate temperature. Electron spin resonance (ESR) active defects in the films were observed when the films were deposited at 380 deg. C and 450 deg. C. The ESR signal intensity decreases drastically with increasing deposition temperature. The intrinsic stress correlates very closely to the intensity of the ESR-active defects, that is, the films with larger intrinsic stress have larger ESR-active defects. It is considered that the intrinsic stress was generated because the voids caused by local bond disorder were formed during random network formation among the SiO 4 tetrahedra. This local bond disorder also causes the ESR-active defects

  11. Effects of Dry-Milling and Wet-Milling on Chemical, Physical and Gelatinization Properties of Rice Flour

    Directory of Open Access Journals (Sweden)

    Jitranut Leewatchararongjaroen

    2016-09-01

    Full Text Available Rice flour from nine varieties, subjected to dry- and wet-milling processes, was determined for its physical and chemical properties. The results revealed that milling method had an effect on properties of flour. Wet-milling process resulted in flour with significantly lower protein and ash contents and higher carbohydrate content. Wet-milled flour also tended to have lower lipid content and higher amylose content. In addition, wet-milled rice flour contained granules with smaller average size compared to dry-milled samples. Swelling power at 90 °C of wet-milled samples was higher while solubility was significantly lower than those of dry-milled flour. Dry milling process caused the destruction of the crystalline structure and yielded flour with lower crystallinity compared to wet-milling process, which resulted in significantly lower gelatinization enthalpy.

  12. Si substrate by chemical solution deposition

    Indian Academy of Sciences (India)

    ZnMn2O4 active layer for resistance random access memory (RRAM) was ... The bipolar resistive switching behaviours of the Ag/ZnMn2O4/p+-Si capacitor ... nal electric field were first proposed by Chua (1971). In ... In this work, the spinel ZnMn2O4 films were deposited .... The typical I–V curves plotted in double logarithmic.

  13. Unveiling the wet chemical etching characteristics of polydimethylsiloxane film for soft micromachining applications

    International Nuclear Information System (INIS)

    Kakati, A; Maji, D; Das, S

    2017-01-01

    Micromachining of a polydimethylsiloxane (PDMS) microstructure by wet chemical etching is explored for microelectromechanical systems (MEMS) and microfluidic applications. A 100 µ m thick PDMS film was patterned with different microstructure designs by wet chemical etching using a N-methyl-2-pyrrolidone (C 16 H 36 FN) and tetra-n-butylammonium fluoride (C 5 H 9 NO) mixture solution with 3:1 volume ratio after lithography for studying etching characteristics. The patterning parameters, such as etch rate, surface roughness, pH of etchant solution with time, were thoroughly investigated. A detailed study of surface morphology with etching time revealed nonlinear behaviour of the PDMS surface roughness and etch rate. A maximum rate of 1.45 µ m min −1 for 10 min etching with surface roughness of 360 nm was achieved. A new approach of wet chemical etching with pH controlled doped etchant was introduced for lower surface roughness of etched microstructures, and a constant etch rate during etching. Variation of the etching rate and surface roughness by pH controlled etching was performed by doping 5–15 gm l −1 of silicic acid (SiO 2xH2 O) into the traditional etchant solution. PDMS etching by silicic acid doped etchant solution showed a reduction in surface roughness from 400 nm to 220 nm for the same 15 µ m etching. This study is beneficial for micromachining of various MEMS and microfluidic structures such as micropillars, microchannels, and other PDMS microstructures. (paper)

  14. The effect of dry and wet deposition of condensable vapors on secondary organic aerosols concentrations over the continental US

    Directory of Open Access Journals (Sweden)

    C. Knote

    2015-01-01

    Full Text Available The effect of dry and wet deposition of semi-volatile organic compounds (SVOCs in the gas phase on the concentrations of secondary organic aerosol (SOA is reassessed using recently derived water solubility information. The water solubility of SVOCs was implemented as a function of their volatility distribution within the WRF-Chem regional chemistry transport model, and simulations were carried out over the continental United States for the year 2010. Results show that including dry and wet removal of gas-phase SVOCs reduces annual average surface concentrations of anthropogenic and biogenic SOA by 48 and 63% respectively over the continental US. Dry deposition of gas-phase SVOCs is found to be more effective than wet deposition in reducing SOA concentrations (−40 vs. −8% for anthropogenics, and −52 vs. −11% for biogenics. Reductions for biogenic SOA are found to be higher due to the higher water solubility of biogenic SVOCs. The majority of the total mass of SVOC + SOA is actually deposited via the gas phase (61% for anthropogenics and 76% for biogenics. Results are sensitive to assumptions made in the dry deposition scheme, but gas-phase deposition of SVOCs remains crucial even under conservative estimates. Considering reactivity of gas-phase SVOCs in the dry deposition scheme was found to be negligible. Further sensitivity studies where we reduce the volatility of organic matter show that consideration of gas-phase SVOC removal still reduces average SOA concentrations by 31% on average. We consider this a lower bound for the effect of gas-phase SVOC removal on SOA concentrations. A saturation effect is observed for Henry's law constants above 108 M atm−1, suggesting an upper bound of reductions in surface level SOA concentrations by 60% through removal of gas-phase SVOCs. Other models that do not consider dry and wet removal of gas-phase SVOCs would hence overestimate SOA concentrations by roughly 50%. Assumptions about the water

  15. Low pressure chemical vapour deposition of temperature resistant colour filters

    International Nuclear Information System (INIS)

    Verheijen, J.; Bongaerts, P.; Verspui, G.

    1987-01-01

    The possibility to deposit multilayer colour filters, based on optical inference, by means of Low Pressure Chemical Vapour Deposition (LPCVD) was investigated. The filters were made in a standard LPCVD system by alternate deposition of Si/sub 3/N/sub 4/ and SiO/sub 2/ layers. This resulted in filters with excellent colour uniformity on glass and quartz substrates. No difference was measured between theoretically calculated transmission and the transmission of the filters deposited by LPCVD. Temperature treatment at 600 0 C in air air showed no deterioration of filter quality and optical properties

  16. CHEMICAL VAPOUR DEPOSITION FROM A RADIATION-SENSITIVE PRECURSOR

    DEFF Research Database (Denmark)

    2017-01-01

    The present invention relates in one aspect to a method of depositing a thin film on a substrate by chemical vapour deposition (CVD) from a radiation-sensitive precursor substance. The method comprises the steps of: (i) placing the substrate in a reaction chamber of a CVD system; (ii) heating...... heating pulse followed by an idle period; (iii) during at least one of the idle periods, providing a pressure pulse of precursor substance inside the reaction chamber by feeding at least one precursor substance to the reaction chamber so as to establish a reaction partial pressure for thin film deposition...... is formed. According to a further aspect, the invention relates to a chemical vapour deposition (CVD) system for depositing a thin film onto a substrate using precursor substances containing at least one radiation sensitive species....

  17. Wet-chemical approach for the cell-adhesive modification of polytetrafluoroethylene

    International Nuclear Information System (INIS)

    Gabriel, Matthias; Dahm, Manfred; Vahl, Christian-F

    2011-01-01

    Polytetrafluoroethylene (PTFE), a frequently utilized polymer for the fabrication of synthetic vascular grafts, was surface-modified by means of a wet-chemical process. The inherently non-cell-adhesive polymer does not support cellular attachment, a prerequisite for the endothelialization of luminal surface grafts in small diameter applications. To impart the material with cell-adhesive properties a treatment with sodium-naphthalene provided a basis for the subsequent immobilization of the adhesion promoting RGD-peptide using a hydroxy- and amine-reactive crosslinker. Successful conjugation was shown with cell culture experiments which demonstrated excellent endothelial cell growth on the modified surfaces.

  18. Direct synthesis of nanocrystalline oxide powders by wet-chemical techniques

    Directory of Open Access Journals (Sweden)

    Vladimir V. Srdić

    2010-09-01

    Full Text Available In a recent period there is a great need for increasing the knowledge of tailoring the innovative procedures for the synthesis of electroceramic nanopowders and materials with improved quality for specific application. In order to produce electroceramics with desirable microstructure and properties, synthesis of stoichiometric, ultra-fine and agglomerate free powders with narrow size distributions is one of the most important steps. Within this scope, in the present paper we summarize our recent results on direct synthesis of some important perovskites and ferrites nanopowders by wet-chemical techniques.

  19. L1{sub 0}-FePt films fabricated by wet-chemical route

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Xiaoliang; Xiao, Wen; Bao, Nina; Li, Weimin; Chichvarina, Olga, E-mail: A0077107@nus.edu.sg; Ding, Jun, E-mail: msedingj@nus.edu.sg

    2015-08-31

    In this work, we have developed a method to fabricate FePt films by a combination of chemical deposition and post-annealing. Pt-doped Fe films were deposited on Pt(100 nm)/Ti(50 nm)/SiO{sub 2}/Si substrate using thermal deposition and the as-deposited films were subsequently annealed from 300 °C to 800 °C under 5% H{sub 2}/95% N{sub 2}. FePt films were achieved through diffusion and rearrangement of Fe and Pt atoms in post-annealing process. From X-ray diffraction results, the face-centered cubic (fcc) FePt phase appeared at 300 °C and the transformation from fcc to L1{sub 0} phase started at 400 °C. The L1{sub 0}-FePt film possessed an out-of-plane anisotropy and a coercivity of 729 kA/m after annealing at 600 °C. A further increase in annealing temperature led to lower value of coercivity, probably because of grain growth. In addition, the thickness of Pt-doped Fe films could be controlled from 150 nm to 700 nm by adjusting the amount of surfactant used. Our superconducting quantum interference device analysis showed that Pt dopant could significantly improve the chemical stability of Fe films in air. - Highlights: • We fabricated FePt film by a combination of chemical deposition and post-annealing. • L1{sub 0} FePt film was formed by Fe/Pt diffusion in annealing of Pt-doped Fe film. • L1{sub 0}-phase FePt with high coercivity and small out-of-plane anisotropy • Relatively small amount of Pt dopant can enhance chemical stability greatly. • We studied structure and magnetic property of as-deposited and annealed FePt film.

  20. Advances in the chemical vapor deposition (CVD) of Tantalum

    DEFF Research Database (Denmark)

    Mugabi, James Atwoki; Eriksen, Søren; Christensen, Erik

    2014-01-01

    The chemical stability of tantalum in hot acidic media has made it a key material in the protection of industrial equipment from corrosion under such conditions. The Chemical Vapor Deposition of tantalum to achieve such thin corrosion resistant coatings is one of the most widely mentioned examples...

  1. The chemical vapor deposition of zirconium carbide onto ceramic substrates

    International Nuclear Information System (INIS)

    Glass A, John Jr.; Palmisiano, Nick Jr.; Welsh R, Edward

    1999-01-01

    Zirconium carbide is an attractive ceramic material due to its unique properties such as high melting point, good thermal conductivity, and chemical resistance. The controlled preparation of zirconium carbide films of superstoichiometric, stoichiometric, and substoichiometric compositions has been achieved utilizing zirconium tetrachloride and methane precursor gases in an atmospheric pressure high temperature chemical vapor deposition system

  2. Characterization and photo-chemical applications of nano-ZnO prepared by wet chemical and thermal decomposition methods

    International Nuclear Information System (INIS)

    Mousa, M.A.; Bayoumy, W.A.A.; Khairy, M.

    2013-01-01

    Graphical abstract: - Highlights: • Nano-ZnO particles were synthesized by soft-wet precipitation and dry methods. • ZnO nanoparticle with different morphologies was obtained. • Nano ZnO samples showed a high photocatalytic activity. • ZnO nanoparticle showed strong ultraviolet emission at room temperature. • The samples showed high biological activity depending on their synthetic method. - Abstract: Nano-crystalline ZnO particles were synthesized using two different routes: soft-wet and dry methods. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to identify the particles structures and morphologies, while X-ray diffraction (XRD) was used for verifying the particles crystal structure. The thermal stabilities of the particles were examined through thermal gravimetric analysis technique and their surface areas were calculated using BET method. Moreover, the photocatalytic activities were evaluated using UV–vis spectroscopy and photoluminescence (PL) characterization. The results showed that all the prepared ZnO samples possess a hexagonal wurtzite structure with high purity. Different particle sizes and morphologies of spheres, rods and wires were obtained depending on the preparation method used. Particle sizes obtained by the dry method are smaller than that found by the wet chemical method. The effects of both particle size and morphology on each of surface as well as optical properties, photocatalytic activity, dye/ZnO solar cell efficiency and biological activity have been studied and discussed

  3. Controlling the resistivity gradient in chemical vapor deposition-deposited aluminum-doped zinc oxide

    NARCIS (Netherlands)

    Ponomarev, M. V.; Verheijen, M. A.; Keuning, W.; M. C. M. van de Sanden,; Creatore, M.

    2012-01-01

    Aluminum-doped ZnO (ZnO:Al) grown by chemical vapor deposition (CVD) generally exhibit a major drawback, i.e., a gradient in resistivity extending over a large range of film thickness. The present contribution addresses the plasma-enhanced CVD deposition of ZnO: Al layers by focusing on the control

  4. Tandem solar cells deposited using hot-wire chemical vapor deposition

    NARCIS (Netherlands)

    Veen, M.K. van

    2003-01-01

    In this thesis, the application of the hot-wire chemical vapor deposition (HWCVD) technique for the deposition of silicon thin films is described. The HWCVD technique is based on the dissociation of silicon-containing gasses at the catalytic surface of a hot filament. Advantages of this technique

  5. Accessing the Impact of Sea-Salt Emissions on Aerosol Chemical Formation and Deposition Over Pearl River Delta, China

    Science.gov (United States)

    Fan, Q.; Wang, X.; Liu, Y.; Wu, D.; Chan, P. W.; Fan, S.; Feng, Y.

    2015-12-01

    Sea-salt aerosol (SSA) emissions have a significant impact on aerosol pollution and haze formation in the coastal areas. In this study, Models-3/CMAQ modeling system was utilized to access the impact of SSA emissions on aerosol chemical formation and deposition over Pearl River Delta (PRD), China in July 2006. More SSAs were transported inland from the open-ocean under the southeast wind in summertime. Two experiments (with and without SSA emissions in the CMAQ model) were set up to compare the modeling results with each other. The results showed that the increase of sulfate concentrations were more attributable to the primary emissions of coarse SO42- particles in SSA, while the increase of nitrate concentrations were more attributable to secondary chemical formations, known as the mechanisms of chloride depletion in SSA. In the coastal areas, 17.62 % of SO42-, 26.6% of NO3- and 38.2% of PM10 were attributed to SSA emissions, while those portions were less than 1% in the inland areas. The increases of PM10 and its components due to SSA emissions resulted in higher deposition fluxes over PRD, particularly in the coastal areas, except for the wet deposition of nitrate. Nitrate was more sensitive to SSA emissions in chemical formations than sulfate and dry deposition of aerosol was also more sensitive than that for wet deposition. Process analysis of sulfate and nitrate was applied to find out the difference of physical and chemical mechanisms between Guangzhou (the inland areas) and Zhuhai (the coastal areas). The negative contributions of dry deposition process to both sulfate and nitrate concentrations increased if SSA emissions were taken into account in the model, especially for Zhuhai. The negative contributions of cloud process also increased due to cloud scavenging and wet deposition process. In the coastal area, the gas-to-particle conversions became more active with high contributions of aerosol process to nitrate concentrations.

  6. Stratigraphy and sedimentology of a dry to wet eolian depositional system, Burns formation, Meridiani Planum, Mars

    Science.gov (United States)

    Grotzinger, J. P.; Arvidson, R. E.; Bell, J. F.; Calvin, W.; Clark, B. C.; Fike, D. A.; Golombek, M.; Greeley, R.; Haldemann, A.; Herkenhoff, K. E.; Jolliff, B. L.; Knoll, A. H.; Malin, M.; McLennan, S. M.; Parker, T.; Soderblom, L.; Sohl-Dickstein, J. N.; Squyres, S. W.; Tosca, N. J.; Watters, W. A.

    2005-11-01

    Outcrop exposures of sedimentary rocks at the Opportunity landing site (Meridiani Planum) form a set of genetically related strata defined here informally as the Burns formation. This formation can be subdivided into lower, middle, and upper units which, respectively, represent eolian dune, eolian sand sheet, and mixed eolian sand sheet and interdune facies associations. Collectively, these three units are at least 7 m thick and define a "wetting-upward" succession which records a progressive increase in the influence of groundwater and, ultimately, surface water in controlling primary depositional processes. The Burns lower unit is interpreted as a dry dune field (though grain composition indicates an evaporitic source), whose preserved record of large-scale cross-bedded sandstones indicates either superimposed bedforms of variable size or reactivation of lee-side slip faces by episodic (possibly seasonal) changes in wind direction. The boundary between the lower and middle units is a significant eolian deflation surface. This surface is interpreted to record eolian erosion down to the capillary fringe of the water table, where increased resistance to wind-induced erosion was promoted by increased sediment cohesiveness in the capillary fringe. The overlying Burns middle unit is characterized by fine-scale planar-laminated to low-angle-stratified sandstones. These sandstones accumulated during lateral migration of eolian impact ripples over the flat to gently undulating sand sheet surface. In terrestrial settings, sand sheets may form an intermediate environment between dune fields and interdune or playa surfaces. The contact between the middle and upper units of the Burns formation is interpreted as a diagenetic front, where recrystallization in the phreatic or capillary zones may have occurred. The upper unit of the Burns formation contains a mixture of sand sheet facies and interdune facies. Interdune facies include wavy bedding, irregular lamination with

  7. CdS films deposited by chemical bath under rotation

    International Nuclear Information System (INIS)

    Oliva-Aviles, A.I.; Patino, R.; Oliva, A.I.

    2010-01-01

    Cadmium sulfide (CdS) films were deposited on rotating substrates by the chemical bath technique. The effects of the rotation speed on the morphological, optical, and structural properties of the films were discussed. A rotating substrate-holder was fabricated such that substrates can be taken out from the bath during the deposition. CdS films were deposited at different deposition times (10, 20, 30, 40 and 50 min) onto Corning glass substrates at different rotation velocities (150, 300, 450, and 600 rpm) during chemical deposition. The chemical bath was composed by CdCl 2 , KOH, NH 4 NO 3 and CS(NH 2 ) 2 as chemical reagents and heated at 75 deg. C. The results show no critical effects on the band gap energy and the surface roughness of the CdS films when the rotation speed changes. However, a linear increase on the deposition rate with the rotation energy was observed, meanwhile the stoichiometry was strongly affected by the rotation speed, resulting a better 1:1 Cd/S ratio as speed increases. Rotation effects may be of interest in industrial production of CdTe/CdS solar cells.

  8. CdS films deposited by chemical bath under rotation

    Energy Technology Data Exchange (ETDEWEB)

    Oliva-Aviles, A.I., E-mail: aoliva@mda.cinvestav.mx [Centro de Investigacion y de Estudios Avanzados Unidad Merida, Departamento de Fisica Aplicada. A.P. 73-Cordemex, 97310 Merida, Yucatan (Mexico); Patino, R.; Oliva, A.I. [Centro de Investigacion y de Estudios Avanzados Unidad Merida, Departamento de Fisica Aplicada. A.P. 73-Cordemex, 97310 Merida, Yucatan (Mexico)

    2010-08-01

    Cadmium sulfide (CdS) films were deposited on rotating substrates by the chemical bath technique. The effects of the rotation speed on the morphological, optical, and structural properties of the films were discussed. A rotating substrate-holder was fabricated such that substrates can be taken out from the bath during the deposition. CdS films were deposited at different deposition times (10, 20, 30, 40 and 50 min) onto Corning glass substrates at different rotation velocities (150, 300, 450, and 600 rpm) during chemical deposition. The chemical bath was composed by CdCl{sub 2}, KOH, NH{sub 4}NO{sub 3} and CS(NH{sub 2}){sub 2} as chemical reagents and heated at 75 deg. C. The results show no critical effects on the band gap energy and the surface roughness of the CdS films when the rotation speed changes. However, a linear increase on the deposition rate with the rotation energy was observed, meanwhile the stoichiometry was strongly affected by the rotation speed, resulting a better 1:1 Cd/S ratio as speed increases. Rotation effects may be of interest in industrial production of CdTe/CdS solar cells.

  9. Chemical vapor deposition of tetraboron silicide whiskers

    International Nuclear Information System (INIS)

    Motozima, Seizi; Sugiyama, Kozoh; Takahashi, Yasutaka

    1975-01-01

    Growth conditions of B 4 Si whiskers were investigated at the temperature range of 1000 - 1100 0 C. Optimum composition of halides was determined as BCl 3 /SiCl 4 =2 - 0.5, and BCl 3 =1 - 6 vol%, SiCl 4 =1 - 7 vol%. Gold had an excellent impurity effect with optimum concentration of 20 - 50 μg/cm 2 on whisker growth, and gave wool like whiskers of 0.1 - 1 μ in thickness and 0.5 - 2 mm in length. B 4 Si whisker growth was explained in terms of a tip VLS mechanism, for a drop-like deposit of impurity was observed on each tip. (auth.)

  10. Synthesis of ZnO nanopencils using wet chemical method and its investigation as LPG sensor

    International Nuclear Information System (INIS)

    Shimpi, Navinchandra G.; Jain, Shilpa; Karmakar, Narayan; Shah, Akshara; Kothari, D.C.; Mishra, Satyendra

    2016-01-01

    Highlights: • Synthesis using a simple and cost-effective wet chemical process. • Uniform, monodispersed and pure nanoparticles. • Pencil shaped rods with sharp tips. • Understanding of Growth mechanism. • Efficient LPG sensing with high response. • Morphology dependent sensing. - Abstract: ZnO nanopencils (NPCs) were prepared by a novel wet chemical process, using triethanolamine (TEA) as a mild base, which is relatively simple and cost effective method as compared to hydrothermal method. ZnO NPCs were characterized using powder X-ray diffraction (XRD), Fourier Transform Infra-Red (FTIR) spectroscopy in mid-IR and far-IR regions, X-ray Photoelectron Spectroscopy (XPS), UV–vis (UV–vis) absorption spectroscopy, room temperature Photoluminescence (PL) spectroscopy and Field Emission Scanning Electron Microscopy (FESEM). ZnO NPCs obtained, were highly pure, uniform and monodispersed.XRD pattern indicated hexagonal unit cell structure with preferred orientation along the c-axis. Sensing behaviour of ZnO NPCs was studied towards Liquefied Petroleum Gas (LPG) at different operating temperatures. The study shows that ZnO NPCs were most sensitive and promising candidate for detection of LPG at 250 °C with gas sensitivity > 60%. The high response towards LPG is due to high surface area of ZnO NPCs and their parallel alignment.

  11. Synthesis of ZnO nanopencils using wet chemical method and its investigation as LPG sensor

    Energy Technology Data Exchange (ETDEWEB)

    Shimpi, Navinchandra G., E-mail: navin_shimpi@rediffmail.com [Department of Chemistry, University of Mumbai, Santacruz (East), Mumbai-400098 (India); Jain, Shilpa [Department of Chemistry, University of Mumbai, Santacruz (East), Mumbai-400098 (India); Karmakar, Narayan [Department of Physics, University of Mumbai, Santacruz (East), Mumbai-400098 (India); Shah, Akshara [Department of Chemistry, University of Mumbai, Santacruz (East), Mumbai-400098 (India); Kothari, D.C. [Department of Physics, University of Mumbai, Santacruz (East), Mumbai-400098 (India); National Centre for Nanosciences & Nanotechnology, University of Mumbai, Santacruz (East), Mumbai-400098 (India); Mishra, Satyendra [University Institute of Chemical Technology, North Maharashtra University, Jalgaon (India)

    2016-12-30

    Highlights: • Synthesis using a simple and cost-effective wet chemical process. • Uniform, monodispersed and pure nanoparticles. • Pencil shaped rods with sharp tips. • Understanding of Growth mechanism. • Efficient LPG sensing with high response. • Morphology dependent sensing. - Abstract: ZnO nanopencils (NPCs) were prepared by a novel wet chemical process, using triethanolamine (TEA) as a mild base, which is relatively simple and cost effective method as compared to hydrothermal method. ZnO NPCs were characterized using powder X-ray diffraction (XRD), Fourier Transform Infra-Red (FTIR) spectroscopy in mid-IR and far-IR regions, X-ray Photoelectron Spectroscopy (XPS), UV–vis (UV–vis) absorption spectroscopy, room temperature Photoluminescence (PL) spectroscopy and Field Emission Scanning Electron Microscopy (FESEM). ZnO NPCs obtained, were highly pure, uniform and monodispersed.XRD pattern indicated hexagonal unit cell structure with preferred orientation along the c-axis. Sensing behaviour of ZnO NPCs was studied towards Liquefied Petroleum Gas (LPG) at different operating temperatures. The study shows that ZnO NPCs were most sensitive and promising candidate for detection of LPG at 250 °C with gas sensitivity > 60%. The high response towards LPG is due to high surface area of ZnO NPCs and their parallel alignment.

  12. Wet chemical synthesis of LiBaF{sub 3} phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Vartika S., E-mail: svmoharil@yahoo.com [Physics Department, Shri Ramdeobaba K.N. Engineering College, Katol Road, Nagpur 440 013 (India); Joshi, C.P. [Physics Department, Shri Ramdeobaba K.N. Engineering College, Katol Road, Nagpur 440 013 (India); Moharil, S.V. [Department of Physics, R.T.M. Nagpur University, Nagpur 440 010 (India)

    2013-12-05

    Highlights: •LiBaF{sub 3}:RE{sup 3+} phosphors synthesized by a simple wet chemical method. •Ce{sup 3+} and Tb{sup 3+} emissions observed in as-prepared powders without any thermal treatment. •Intense Eu{sup 2+} emission observed after annealing in reductive atmosphere. -- Abstract: LiBaF{sub 3} has great potential applications as X-ray storage phosphor, slow neutron imaging, scintillator, vacuum ultraviolet (VUV) optical lithography, etc. Conventionally, LiBaF{sub 3} is prepared by solid state reaction between the constituent fluorides. However, the preparation of phase pure material and especially single crystals is rather tricky due to incongruent melting. For the first time, a wet chemical preparation of rare earth activated LiBaF{sub 3} is described here. As precipitated powders containing Ce{sup 3+} or Tb{sup 3+} exhibited characteristic luminescence. For observing Eu{sup 2+} emission, it was necessary to heat the powders in a reductive atmosphere. It is suggested that phosphors prepared by this method may prove useful in applications like OSL, X-ray imaging, etc. which do not require large single crystals.

  13. Bottom-Up, Wet Chemical Technique for the Continuous Synthesis of Inorganic Nanoparticles

    Directory of Open Access Journals (Sweden)

    Annika Betke

    2014-01-01

    Full Text Available Continuous wet chemical approaches for the production of inorganic nanoparticles are important for large scale production of nanoparticles. Here we describe a bottom-up, wet chemical method applying a microjet reactor. This technique allows the separation between nucleation and growth in a continuous reactor environment. Zinc oxide (ZnO, magnetite (Fe3O4, as well as brushite (CaHPO4·2H2O, particles with a small particle size distribution can be obtained continuously by using the rapid mixing of two precursor solutions and the fast removal of the nuclei from the reaction environment. The final particles were characterized by FT-IR, TGA, DLS, XRD and SEM techniques. Systematic studies on the influence of the different process parameters, such as flow rate and process temperature, show that the particle size can be influenced. Zinc oxide was obtained with particle sizes between 44 nm and 102 nm. The obtained magnetite particles have particle sizes in the range of 46 nm to 132 nm. Brushite behaves differently; the obtained particles were shaped like small plates with edge lengths between 100 nm and 500 nm.

  14. Optimization of wet lay-up conditions for steam generators hydrazine chemical treatment

    International Nuclear Information System (INIS)

    Long, A.; Organista, M.; Brun, C.; Combrade, P.

    2002-01-01

    Since a long time, hydrazine is used as a chemical agent to prevent corrosion of unalloyed steels. This is a conventional treatment widely used by nuclear power plant operators. But its application in SG lay-up at French nuclear power plants has, however, lead to some drawbacks. Effluent releases: Due to regulation relative to release of hydrazine and alkaline chemical compounds, some plant operators limit the concentrations of reagents to levels that could lead to insufficient protection of materials. Safety hazards associated with SG nitrogen blanketing: Prohibiting use of nitrogen blankets for SG wet lay-up due to associated safety hazards could likewise jeopardize corrosion protection at normally specified hydrazine levels. As the exact limits of hydrazine action against corrosion during SG lay-up are not well known, it is sometimes difficult to evaluate the risk associated to low dosage of N 2 H 4 . In order to answer to these problems, Framatome ANP (France) decided to carry out a test program aimed to determine the limit conditions for use of hydrazine in a wet lay-up environment. (authors)

  15. Structural and Optical Properties of Chemical Bath Deposited Silver Oxide Thin Films: Role of Deposition Time

    Directory of Open Access Journals (Sweden)

    A. C. Nwanya

    2013-01-01

    Full Text Available Silver oxide thin films were deposited on glass substrates at a temperature of 50°C by chemical bath deposition technique under different deposition times using pure AgNO3 precursor and triethanolamine as the complexing agent. The chemical analysis based on EDX technique shows the presence of Ag and O at the appropriate energy levels. The morphological features obtained from SEM showed that the AgxO structures varied as the deposition time changes. The X-ray diffraction showed the peaks of Ag2O and AgO in the structure. The direct band gap and the refractive index increased as the deposition time increased and was in the range of 1.64–1.95 eV and 1.02–2.07, respectively. The values of the band gap and refractive index obtained indicate possible applications in photovoltaic and photothermal systems.

  16. Oxygen Barrier Coating Deposited by Novel Plasma-enhanced Chemical Vapor Deposition

    DEFF Research Database (Denmark)

    Jiang, Juan; Benter, M.; Taboryski, Rafael Jozef

    2010-01-01

    We report the use of a novel plasma-enhanced chemical vapor deposition chamber with coaxial electrode geometry for the SiOx deposition. This novel plasma setup exploits the diffusion of electrons through the inner most electrode to the interior samples space as the major energy source. This confi......We report the use of a novel plasma-enhanced chemical vapor deposition chamber with coaxial electrode geometry for the SiOx deposition. This novel plasma setup exploits the diffusion of electrons through the inner most electrode to the interior samples space as the major energy source...... effect of single-layer coatings deposited under different reaction conditions was studied. The coating thickness and the carbon content in the coatings were found to be the critical parameters for the barrier property. The novel barrier coating was applied on different polymeric materials...

  17. Study on stability of a-SiCOF films deposited by plasma enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    Ding Shijin; Zhang Qingquan; Wang Pengfei; Zhang Wei; Wang Jitao

    2001-01-01

    Low-dielectric-constant a-SiCOF films have been prepared from TEOS, C 4 F 8 and Ar by using plasma enhanced chemical vapor deposition method. With the aid of X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR), the chemical bonding configuration, thermal stability and resistance to water of the films are explored

  18. Morphologies and wetting properties of copper film with 3D porous micro-nano hierarchical structure prepared by electrochemical deposition

    International Nuclear Information System (INIS)

    Wang, Hongbin; Wang, Ning; Hang, Tao; Li, Ming

    2016-01-01

    Highlights: • A 3D porous micro-nano hierarchical structure Cu films were prepared. • The evolution of morphology and wettability with deposition time was reported. • The effects of EDA on the microscopic morphology were revealed. • A high contact angle of 162.1° was measured when deposition time is 5 s. • The mechanism of super-hydrophobicity was illustrated by two classical models. - Abstract: Three-dimensional porous micro-nano hierarchical structure Cu films were prepared by electrochemical deposition with the Hydrogen bubble dynamic template. The morphologies of the deposited films characterized by Scanning Electronic Microscopy (SEM) exhibit a porous micro-nano hierarchical structure, which consists of three levels in different size scales, namely the honeycomb-like microstructure, the dendritic substructure and the nano particles. Besides, the factors which influenced the microscopic morphology were studied, including the deposition time and the additive Ethylene diamine. By measuring the water contact angle, the porous copper films were found to be super-hydrophobic. The maximum of the contact angles could reach as high as 162.1°. An empirical correlation between morphologies and wetting properties was revealed for the first time. The pore diameter increased simultaneously with the deposition time while the contact angle decreased. The mechanism was illustrated by two classical models. Such super-hydrophobic three-dimensional hierarchical micro-nano structure is expected to have practical application in industry.

  19. Effects of deposition time in chemically deposited ZnS films in acidic solution

    Energy Technology Data Exchange (ETDEWEB)

    Haddad, H.; Chelouche, A., E-mail: azeddinechelouche@gmail.com; Talantikite, D.; Merzouk, H.; Boudjouan, F.; Djouadi, D.

    2015-08-31

    We report an experimental study on the synthesis and characterization of zinc sulfide (ZnS) single layer thin films deposited on glass substrates by chemical bath deposition technique in acidic solution. The effect of deposition time on the microstructure, surface morphology, optical absorption, transmittance, and photoluminescence (PL) was investigated by X-ray diffraction (XRD), scanning electronic microscopy (SEM), UV-Vis–NIR spectrophotometry and photoluminescence (PL) spectroscopy. The results showed that the samples exhibit wurtzite structure and their crystal quality is improved by increasing deposition time. The latter, was found to affect the morphology of the thin films as showed by SEM micrographs. The optical measurements revealed a high transparency in the visible range and a dependence of absorption edge and band gap on deposition time. The room temperature PL spectra indicated that all ZnS grown thin films emit a UV and blue light, while the band intensities are found to be dependent on deposition times. - Highlights: • Single layer ZnS thin films were deposited by CBD in acidic solution at 95 °C. • The effect of deposition time was investigated. • Coexistence of ZnS and ZnO hexagonal structures for time deposition below 2 h • Thicker ZnS films were achieved after monolayer deposition for 5 h. • The highest UV-blue emission observed in thin film deposited at 5 h.

  20. Fabrication and evaluation of chemically vapor deposited tungsten heat pipe.

    Science.gov (United States)

    Bacigalupi, R. J.

    1972-01-01

    A network of lithium-filled tungsten heat pipes is being considered as a method of heat extraction from high temperature nuclear reactors. The need for material purity and shape versatility in these applications dictates the use of chemically vapor deposited (CVD) tungsten. Adaptability of CVD tungsten to complex heat pipe designs is shown. Deposition and welding techniques are described. Operation of two lithium-filled CVD tungsten heat pipes above 1800 K is discussed.

  1. Chemical solution deposition: a path towards low cost coated conductors

    International Nuclear Information System (INIS)

    Obradors, X; Puig, T; Pomar, A; Sandiumenge, F; Pinol, S; Mestres, N; Castano, O; Coll, M; Cavallaro, A; Palau, A; Gazquez, J; Gonzalez, J C; Gutierrez, J; Roma, N; Ricart, S; Moreto, J M; Rossell, M D; Tendeloo, G van

    2004-01-01

    The achievement of low cost deposition techniques for high critical current YBa 2 Cu 3 O 7 coated conductors is one of the major objectives to achieve a widespread use of superconductivity in power applications. Chemical solution deposition techniques are appearing as a very promising methodology to achieve epitaxial oxide thin films at a low cost, so an intense effort is being carried out to develop routes for all chemical coated conductor tapes. In this work recent achievements will be presented towards the goal of combining the deposition of different type of buffer layers on metallic substrates based on metal-organic decomposition with the growth of YBa 2 Cu 3 O 7 layers using the trifluoroacetate route. The influence of processing parameters on the microstructure and superconducting properties will be stressed. High critical currents are demonstrated in 'all chemical' multilayers

  2. Chemical solution deposition of LaMnO3-based films for coated conductors

    International Nuclear Information System (INIS)

    Shi, D Q; Zhu, X B; Kim, J H; Wang, L; Zeng, R; Dou, S X; Lei, H C; Sun, Y P

    2008-01-01

    LaMnO 3 -based films were prepared using the chemical solution deposition method. It was found that the films on perovskite oxide single crystal substrates are highly (h00)-oriented when the annealing atmosphere is oxygen or air; however, when the substrate is yttrium-stabilized ZrO 2 , only the La 1-x Na x MnO 3 films are highly (h00)-oriented, and other LaMnO 3 -based films are (110)-oriented. Under a reducing annealing atmosphere, the atmosphere must be wet in order to create a suitable oxygen partial pressure to crystallize the LaMnO 3 -based films. After annealing under a wet reducing atmosphere the LaMnO 3 -based films are (110)-oriented when the films are directly deposited on Ni tapes; however, when SrTiO 3 -buffered Ni tapes are used, the LaMnO 3 films are (h00)-oriented, which is suitable for subsequent growth of YBCO. The results suggest that it is possible to tune the orientation of buffer layers using suitable templates, which can widen the selection of buffer layers for coated conductors in the all metallorganic deposition approach

  3. Chemical vapor deposition (CVD) of uranium for alpha spectrometry

    International Nuclear Information System (INIS)

    Ramirez V, M. L.; Rios M, C.; Ramirez O, J.; Davila R, J. I.; Mireles G, F.

    2015-09-01

    The uranium determination through radiometric techniques as alpha spectrometry requires for its proper analysis, preparation methods of the source to analyze and procedures for the deposit of this on a surface or substrate. Given the characteristics of alpha particles (small penetration distance and great loss of energy during their journey or its interaction with the matter), is important to ensure that the prepared sources are thin, to avoid problems of self-absorption. The routine methods used for this are the cathodic electro deposition and the direct evaporation, among others. In this paper the use of technique of chemical vapor deposition (CVD) for the preparation of uranium sources is investigated; because by this, is possible to obtain thin films (much thinner than those resulting from electro deposition or evaporation) on a substrate and comprises reacting a precursor with a gas, which in turn serves as a carrier of the reaction products to achieve deposition. Preliminary results of the chemical vapor deposition of uranium are presented, synthesizing and using as precursor molecule the uranyl acetylacetonate, using oxygen as carrier gas for the deposition reaction on a glass substrate. The uranium films obtained were found suitable for alpha spectrometry. The variables taken into account were the precursor sublimation temperatures and deposition temperature, the reaction time and the type and flow of carrier gas. Of the investigated conditions, two depositions with encouraging results that can serve as reference for further work to improve the technique presented here were selected. Alpha spectra obtained for these depositions and the characterization of the representative samples by scanning electron microscopy and X-ray diffraction are also presented. (Author)

  4. Wet deposition of mercury in Qingdao, a coastal urban city in China: Concentrations, fluxes, and influencing factors

    Science.gov (United States)

    Chen, Lufeng; Li, Yanbin; Liu, Chang; Guo, Lina; Wang, Xiulin

    2018-02-01

    Mercury (Hg) is a global pollutant of public concern because of its high toxicity and capability for worldwide distribution via long-range atmospheric transportation. Wet atmospheric deposition is an important source of Hg in both terrestrial and aquatic environments. Concentrations of various Hg species in precipitation were monitored from March 2016 to February 2017 in a coastal urban area of Qingdao, and their wet deposition fluxes were estimated. The results showed that the volume-weighted mean (VWM) concentrations of total mercury (THg), reactive mercury (RHg), dissolved THg (DTHg), particulate THg (PTHg), total methylmercury (TMeHg), and dissolved and particulate MeHg (DMeHg and PMeHg) in Qingdao's precipitation were 13.6, 1.5, 5.4, 8.2, 0.38, 0.15, and 0.22 ng L-1, respectively, and their annual deposition fluxes were estimated to be 5703.0 (THg), 666.6 (RHg), 2304.0 (DTHg), 3470.4 (PTHg), 161.6 (TMeHg), 64.0 (DMeHg), and 95.7 (PMeHg) ng m-2 y-1, respectively. A relatively high proportion of MeHg in THg was observed in precipitation (3.0 ± 2.6%) possibly due to higher methylation and contributions from an oceanic source to MeHg in the precipitation. Obvious seasonal variations in Hg concentrations and deposition fluxes were observed in the precipitation in Qingdao. Correlation analyses and multiple regression analyses showed that SO2, pH, and NO3- were the controlling factors for THg in precipitation, whereas the MeHg concentration was primarily controlled by the SO2, WS, Cl-, and THg concentrations. PM2.5 and Cl- were the major controlling factors for PMeHg/TMeHg, whereas the TMeHg/THg ratio was mainly influenced by Cl-. The THg and MeHg fluxes were primarily controlled by precipitation, whereas Cl- was also an important factor for the MeHg wet deposition flux. The results of a 72-h backward trajectory analysis in the study region with the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model indicated that Hg deposition in Qingdao mainly

  5. Atmospheric dry and wet deposition of sulphur and nitrogen species and assessment of critical loads of acidic deposition exceedance in South Africa

    Directory of Open Access Journals (Sweden)

    Stuart J. Piketh

    2011-03-01

    Full Text Available We tested the hypothesis that acidic atmospheric pollution deposition, originating from the South African central industrial area, poses an environmental threat across a larger region within the dispersal footprint. A network of 37 passive monitoring sites to measure SO2 and NO2 was operated from August 2005 to September 2007. The area extended over the entire northern and eastern interior of South Africa. Monitoring locations were chosen to avoid direct impacts from local sources such as towns, mines and highways. Dry deposition rates of SO2 and NO2 were calculated from the measured concentrations. Concentrations of sulphur and nitrogen species in wet deposition from a previous study were used in conjunction with measured rainfall for the years 2006 and 2007 to estimate the wet deposition over the region. The calculated total (non-organic acidic deposition formed the basis for an assessment of exceedance of critical loads based on sensitivity of the regional soils. Regional soil sensitivity was determined by combining two major soil attributes available in the World Inventory of Soil Emission Potentials (International Soil Reference and Information Centre. Results indicate that certain parts of the central pollution source area on the South African Highveld have the potential for critical load exceedance, while limited areas downwind show lower levels of exceedance. Areas upwind and remote areas up and downwind, including forested areas of the Drakensberg escarpment, do not show any exceedance of the critical loads.

  6. Short-term seasonal variability in 7Be wet deposition in a semiarid ecosystem of central Argentina

    International Nuclear Information System (INIS)

    Juri Ayub, J.; Di Gregorio, D.E.; Velasco, H.; Huck, H.; Rizzotto, M.; Lohaiza, F.

    2009-01-01

    The 7 Be wet deposition has been intensively investigated in a semiarid region at San Luis Province, Argentina. From November 2006 to May 2008, the 7 Be content in rainwater was determined in 58 individual rain events, randomly comprising more than 50% of all individual precipitations at the sampling period. 7 Be activity concentration in rainwater ranged from 0.7 ± 0.3 Bq l -1 to 3.2 ± 0.7 Bq l -1 , with a mean value of 1.7 Bq l -1 (sd = 0.53 Bq l -1 ). No relationship was found between 7 Be content in rainwater and (a) rainfall amount, (b) precipitation intensity and (c) elapsed time between events. 7 Be ground deposition was found to be well correlated with rainfall amount (R = 0.92). For the precipitation events considered, the 7 Be depositional fluxes ranged from 1.1 to 120 Bq m -2 , with a mean value of 32.7 Bq m -2 (sd = 29.9 Bq m -2 ). The annual depositional flux was estimated at 1140 ± 120 Bq m -2 y -1 . Assuming the same monthly deposition pattern and that the 7 Be content in soil decreases only through radioactive decay, the seasonal variation of 7 Be areal activity density in soil was estimated. Results of this investigation may contribute to a valuable characterization of 7 Be input in the explored semiarid ecosystem and its potential use as tracer of environmental processes.

  7. Atmospheric deposition of heavy metals due to dry, wet and occult deposition at the altitude profile Achenkirch

    International Nuclear Information System (INIS)

    Stopper, S.

    2001-12-01

    The goal of this work was to determine the height dependence of the three types of deposition throughout a one year time period to be able to get information about their elevational and seasonal behavior. In the time period from October 1998 to November 1999 measurements of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn in aerosol, rain and cloud water were conducted in the Achenkirch-Valley in Tyrol, Austria. Afterwards the dry and occult deposition were modeled. The estimated annual inputs of metals at the two measurement sites Christlumkopf (1758 m a.s.l.) Mueeggerkoel (940 m a.s.l.) and the limits of the national law for protection of forest are shown. The measured depositions at both sites were far below the legal regulations. Due to the much higher occult deposition ratio at the top of the mountain the total annual input at the Christlumkopf was higher than at the Mueeggerkoel. This indicates the potential importance of occult deposition. (author)

  8. Combined wet-chemical process to synthesize 65PMN-35PT nanosized powders

    International Nuclear Information System (INIS)

    Santos, Luis P.S.; Longo, Elson; Leite, Edson R.; Camargo, Emerson R.

    2004-01-01

    Columbite MgNb 2 O 6 precursors were synthesized by a wet-chemical method by means of the dissolution of Nb 2 O 5 .5H 2 O and magnesium carbonate in a solution of oxalic acid. Pure 65PMN-35PT powders could be obtained by the columbite method with the use of the partial oxalate and oxidant peroxo methods. Powders were characterized by X-ray diffraction and FT-Raman spectroscopy showing that pure 65PMN-35PT are obtained when the powders are calcined up to 800 deg. C, without any trace of Pb-Nb pyrochlore. Cubic Pb 1,86 Mg 0.24 Nb 1.76 O 6.5 pyrochlore phase is formed by lead loss in the powders calcined at 900 deg. C and higher temperatures as undoubtedly characterized by Raman spectroscopy

  9. Washing of gel particles in wet chemical manufacture of reactor fuel particles

    International Nuclear Information System (INIS)

    Ringel, H.

    1980-07-01

    In the manufacture of HTR fuel particles and particles of fertile material by wet chemical methods, the ammonium nitrate formed during the precipitation reaction must be washed out of the gel particles. This washing process has been investigated theoretically and experimentally. A counter-current washer has been developed which in particular takes account of the aspects of refabrication - such as compact construction and minimum waste. A counter-current washing column of 17 mm internal diameter and 640 mm length gives to gel particle throughput of 0.65 1/h. The volume ratio of wash water to gel particles is 5, and the residual nitrate concentration in the particles is 7 x 10 -3 mols of NO - 3 /1. (orig.) [de

  10. PEG capped CaS nanoparticles synthesized by wet chemical co-precipitation method

    Science.gov (United States)

    Rekha, S.; Anila, E. I.

    2018-04-01

    Calcium sulfide (CaS) nanoparticles capped with polyethyleneglycol (PEG) were synthesized using wet chemical co-precipitation method. The structural and optical properties of the prepared sample were studied by X-ray diffractogram (XRD), transmission electron microscopy (TEM), diffuse reflectance spectrum (DRS) and photoluminescence (PL) spectrum. The structure of CaS nanoparticles is cubic as demonstrated by the X-ray powder diffraction (XRD) and selected area electron diffraction (SAED) analysis. TEMimage revealed the spherical morphology of the particles with diameter in the range 15-20 nm. The optical band gap of the prepared sample was determined from the DRS and its value was found to be 4.1 eV. The PL studies showed that the relative intensity of the PEG capped CaS nanoparticles was higher than that of uncapped CaS nanoparticles. The presence of various functional groups in the capped samples were examined by Fourier Transform Infrared (FTIR) spectroscopy.

  11. Fabrication of Aligned Polyaniline Nanofiber Array via a Facile Wet Chemical Process.

    Science.gov (United States)

    Sun, Qunhui; Bi, Wu; Fuller, Thomas F; Ding, Yong; Deng, Yulin

    2009-06-17

    In this work, we demonstrate for the first time a template free approach to synthesize aligned polyaniline nanofiber (PN) array on a passivated gold (Au) substrate via a facile wet chemical process. The Au surface was first modified using 4-aminothiophenol (4-ATP) to afford the surface functionality, followed subsequently by an oxidation polymerization of aniline (AN) monomer in an aqueous medium using ammonium persulfate as the oxidant and tartaric acid as the doping agent. The results show that a vertically aligned PANI nanofiber array with individual fiber diameters of ca. 100 nm, heights of ca. 600 nm and a packing density of ca. 40 pieces·µm(-2) , was synthesized. Copyright © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Fabrication and Photovoltaic Characteristics of Coaxial Silicon Nanowire Solar Cells Prepared by Wet Chemical Etching

    Directory of Open Access Journals (Sweden)

    Chien-Wei Liu

    2012-01-01

    Full Text Available Nanostructured solar cells with coaxial p-n junction structures have strong potential to enhance the performances of the silicon-based solar cells. This study demonstrates a radial junction silicon nanowire (RJSNW solar cell that was fabricated simply and at low cost using wet chemical etching. Experimental results reveal that the reflectance of the silicon nanowires (SNWs declines as their length increases. The excellent light trapping was mainly associated with high aspect ratio of the SNW arrays. A conversion efficiency of ∼7.1% and an external quantum efficiency of ∼64.6% at 700 nm were demonstrated. Control of etching time and diffusion conditions holds great promise for the development of future RJSNW solar cells. Improving the electrode/RJSNW contact will promote the collection of carries in coaxial core-shell SNW array solar cells.

  13. Simulation of the evolution of fused silica's surface defect during wet chemical etching

    Science.gov (United States)

    Liu, Taixiang; Yang, Ke; Li, Heyang; Yan, Lianghong; Yuan, Xiaodong; Yan, Hongwei

    2017-08-01

    Large high-power-laser facility is the basis for achieving inertial confinement fusion, one of whose missions is to make fusion energy usable in the near future. In the facility, fused silica optics plays an irreplaceable role to conduct extremely high-intensity laser to fusion capsule. But the surface defect of fused silica is a major obstacle limiting the output power of the large laser facility and likely resulting in the failure of ignition. To mitigate, or event to remove the surface defect, wet chemical etching has been developed as a practical way. However, how the surface defect evolves during wet chemical etching is still not clearly known so far. To address this problem, in this work, the three-dimensional model of surface defect is built and finite difference time domain (FDTD) method is developed to simulate the evolution of surface defect during etching. From the simulation, it is found that the surface defect will get smooth and result in the improvement of surface quality of fused silica after etching. Comparatively, surface defects (e.g. micro-crack, scratch, series of pinholes, etc.) of a typical fused silica at different etching time are experimentally measured. It can be seen that the simulation result agrees well with the result of experiment, indicating the FDTD method is valid for investigating the evolution of surface defect during etching. With the finding of FDTD simulation, one can optimize the treatment process of fused silica in practical etching or even to make the initial characterization of surface defect traceable.

  14. Functionalization of Hydrogenated Chemical Vapour Deposition-Grown Graphene by On-Surface Chemical Reactions

    Czech Academy of Sciences Publication Activity Database

    Drogowska, Karolina; Kovaříček, Petr; Kalbáč, Martin

    2017-01-01

    Roč. 23, č. 17 (2017), s. 4022-4022 ISSN 1521-3765 Institutional support: RVO:61388955 Keywords : Chemical vapor deposition * Hydrogenation * Graphene Subject RIV: CF - Physical ; Theoretical Chemistry

  15. Chemical vapor deposition: A technique for applying protective coatings

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, T.C. Sr.; Bowman, M.G.

    1979-01-01

    Chemical vapor deposition is discussed as a technique for applying coatings for materials protection in energy systems. The fundamentals of the process are emphasized in order to establish a basis for understanding the relative advantages and limitations of the technique. Several examples of the successful application of CVD coating are described. 31 refs., and 18 figs.

  16. Ballistic transport in graphene grown by chemical vapor deposition

    NARCIS (Netherlands)

    Calado, V.E.; Zhu, S.E.; Goswami, S.; Xu, Q.; Watanabe, K.; Taniguchi, T.; Janssen, G.C.A.M.; Vandersypen, L.M.K.

    2014-01-01

    In this letter, we report the observation of ballistic transport on micron length scales in graphene synthesised by chemical vapour deposition (CVD). Transport measurements were done on Hall bar geometries in a liquid He cryostat. Using non-local measurements, we show that electrons can be

  17. Microscopic characterisation of suspended graphene grown by chemical vapour deposition

    NARCIS (Netherlands)

    Bignardi, L.; Dorp, W.F. van; Gottardi, S.; Ivashenko, O.; Dudin, P.; Barinov, A.; de Hosson, J.T.M.; Stöhr, M.; Rudolf, P.

    2013-01-01

    We present a multi-technique characterisation of graphene grown by chemical vapour deposition (CVD) and thereafter transferred to and suspended on a grid for transmission electron microscopy (TEM). The properties of the electronic band structure are investigated by angle-resolved photoelectron

  18. Influence of deposition time on the properties of chemical bath deposited manganese sulfide thin films

    Directory of Open Access Journals (Sweden)

    Anuar Kassim

    2010-12-01

    Full Text Available Manganese sulfide thin films were chemically deposited from an aqueous solution containing manganese sulfate, sodium thiosulfate and sodium tartrate. The influence of deposition time (2, 3, 6 and 8 days on the properties of thin films was investigated. The structure and surface morphology of the thin films were studied by X-ray diffraction and atomic force microscopy, respectively. In addition, in order to investigate the optical properties of the thin films, the UV-visible spectrophotometry was used. The XRD results indicated that the deposited MnS2 thin films exhibited a polycrystalline cubic structure. The number of MnS2 peaks on the XRD patterns initially increased from three to six peaks and then decreased to five peaks, as the deposition time was increased from 2 to 8 days. From the AFM measurements, the film thickness and surface roughness were found to be dependent on the deposition time.

  19. SnS thin films deposited by chemical bath deposition, dip coating and SILAR techniques

    Science.gov (United States)

    Chaki, Sunil H.; Chaudhary, Mahesh D.; Deshpande, M. P.

    2016-05-01

    The SnS thin films were synthesized by chemical bath deposition (CBD), dip coating and successive ionic layer adsorption and reaction (SILAR) techniques. In them, the CBD thin films were deposited at two temperatures: ambient and 70 °C. The energy dispersive analysis of X-rays (EDAX), X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and optical spectroscopy techniques were used to characterize the thin films. The electrical transport properties studies on the as-deposited thin films were done by measuring the I-V characteristics, DC electrical resistivity variation with temperature and the room temperature Hall effect. The obtained results are deliberated in this paper.

  20. ZnSe thin films by chemical bath deposition method

    Energy Technology Data Exchange (ETDEWEB)

    Lokhande, C.D.; Patil, P.S.; Tributsch, H. [Hahn-Meitner-Institute, Bereich Physikalische Chemie, Abt. CS, Glienicker Strasse-100, D-14109 Berlin (Germany); Ennaoui, A. [Hahn-Meitner-Institute, Bereich Physikalische Chemie, Abt. CG, Glienicker Strasse-100, D-14109 Berlin (Germany)

    1998-09-04

    The ZnSe thin films have been deposited onto glass substrates by the simple chemical bath deposition method using selenourea as a selenide ion source from an aqueous alkaline medium. The effect of Zn ion concentration, bath temperature and deposition time period on the quality and thickness of ZnSe films has been studied. The ZnSe films have been characterized by XRD, TEM, EDAX, TRMC (time-resolved microwave conductivity), optical absorbance and RBS techniques for their structural, compositional, electronic and optical properties. The as-deposited ZnSe films are found to be amorphous, Zn rich with optical band gap, Eg, equal to 2.9 eV

  1. Preparation of hafnium carbide by chemical vapor deposition

    International Nuclear Information System (INIS)

    Hertz, Dominique.

    1974-01-01

    Hard, adhesive coatings of single-phase hafnium carbide were obtained by chemical vapor reaction in an atmosphere containing hafnium tetrachloride, methane and a large excess of hydrogen. By varying the gas phase composition and temperature the zones of formation of the different solid phases were studied and the growth of elementary hafnium and carbon deposits evaluated separately. The results show that the mechanism of hafnium carbide deposition does not hardly involve phenomene of homogeneous-phase methane decomposition or tetrachloride reduction by hydrogen unless the atmosphere is very rich or very poor in methane with respect to tetrachloride. However, hydrogen acting inversely on these two reactions, affects the stoichiometry of the substance deposited. The methane decomposition reaction is fairly slow, the reaction leading to hafnium carbide deposition is faster and that of tetrachloride reduction by hydrogen is quite fast [fr

  2. The atmospheric chemical vapour deposition of coatings on glass

    International Nuclear Information System (INIS)

    Sanderson, Kevin David

    1996-01-01

    The deposition of thin films of indium oxide, tin doped indium oxide (ITO) and titanium nitride for solar control applications have been investigated by Atmospheric Chemical Vapour Deposition (APCVD). Experimental details of the deposition system and the techniques used to characterise the films are presented. Results from investigations into the deposition parameters, the film microstructure and film material properties are discussed. A range of precursors were investigated for the deposition of indium oxide. The effect of pro-mixing the vaporised precursor with an oxidant source and the deposition temperature has been studied. Polycrystalline In 2 O 3 films with a resistivity of 1.1 - 3x10 -3 Ω cm were obtained with ln(thd) 3 , oxygen and nitrogen. The growth of ITO films from ln(thd) 3 , oxygen and a range of tin dopants is also presented. The effect of the dopant precursor, the doping concentration, deposition temperature and the effect of additives on film growth and microstructure is discussed. Control over the preferred orientation growth of ITO has been achieved by the addition of acetate species during film growth. Insitu infra-red spectroscopy has been used to identify the gas phase species and identify the species responsible for the film modification. ITO films with a resistivities of 1.5 - 4x10 -4 Ω cm have been achieved. The deposition of titanium nitride by the APCVD of Ti(NMe 2 ) 4 and a mixture of Ti(NMe 2 ) 4 and ammonia is reported. Contamination of the films and pro-reaction between the precursors in the gas phase is discussed, and the synthesis of new precursors for the deposition of titanium nitride is reported. New precursors have been synthesised under anaerobic conditions and characterised by infra-red spectroscopy, 1 H and 13 C NMR, mass spectrometry, thermal gravemetric analysis and three by single crystal X-ray diffraction. Deposition of titanium nitride utilising two new precursors is reported. (author)

  3. Microbes and associated soluble and volatile chemicals on periodically wet household surfaces.

    Science.gov (United States)

    Adams, Rachel I; Lymperopoulou, Despoina S; Misztal, Pawel K; De Cassia Pessotti, Rita; Behie, Scott W; Tian, Yilin; Goldstein, Allen H; Lindow, Steven E; Nazaroff, William W; Taylor, John W; Traxler, Matt F; Bruns, Thomas D

    2017-09-26

    Microorganisms influence the chemical milieu of their environment, and chemical metabolites can affect ecological processes. In built environments, where people spend the majority of their time, very little is known about how surface-borne microorganisms influence the chemistry of the indoor spaces. Here, we applied multidisciplinary approaches to investigate aspects of chemical microbiology in a house. We characterized the microbial and chemical composition of two common and frequently wet surfaces in a residential setting: kitchen sink and bathroom shower. Microbial communities were studied using culture-dependent and independent techniques, including targeting RNA for amplicon sequencing. Volatile and soluble chemicals from paired samples were analyzed using state-of-the-art techniques to explore the links between the observed microbiota and chemical exudates. Microbial analysis revealed a rich biological presence on the surfaces exposed in kitchen sinks and bathroom shower stalls. Microbial composition, matched for DNA and RNA targets, varied by surface type and sampling period. Bacteria were found to have an average of 25× more gene copies than fungi. Biomass estimates based on qPCR were well correlated with measured total volatile organic compound (VOC) emissions. Abundant VOCs included products associated with fatty acid production. Molecular networking revealed a diversity of surface-borne compounds that likely originate from microbes and from household products. Microbes played a role in structuring the chemical profiles on and emitted from kitchen sinks and shower stalls. Microbial VOCs (mVOCs) were predominately associated with the processing of fatty acids. The mVOC composition may be more stable than that of microbial communities, which can show temporal and spatial variation in their responses to changing environmental conditions. The mVOC output from microbial metabolism on kitchen sinks and bathroom showers should be apparent through careful

  4. A multi-resolution assessment of the Community Multiscale Air Quality (CMAQ model v4.7 wet deposition estimates for 2002–2006

    Directory of Open Access Journals (Sweden)

    K. W. Appel

    2011-05-01

    Full Text Available This paper examines the operational performance of the Community Multiscale Air Quality (CMAQ model simulations for 2002–2006 using both 36-km and 12-km horizontal grid spacing, with a primary focus on the performance of the CMAQ model in predicting wet deposition of sulfate (SO4=, ammonium (NH4+ and nitrate (NO3. Performance of the wet deposition estimates from the model is determined by comparing CMAQ predicted concentrations to concentrations measured by the National Acid Deposition Program (NADP, specifically the National Trends Network (NTN. For SO4= wet deposition, the CMAQ model estimates were generally comparable between the 36-km and 12-km simulations for the eastern US, with the 12-km simulation giving slightly higher estimates of SO4= wet deposition than the 36-km simulation on average. The result is a slightly larger normalized mean bias (NMB for the 12-km simulation; however both simulations had annual biases that were less than ±15 % for each of the five years. The model estimated SO4= wet deposition values improved when they were adjusted to account for biases in the model estimated precipitation. The CMAQ model underestimates NH4+ wet deposition over the eastern US, with a slightly larger underestimation in the 36-km simulation. The largest underestimations occur in the winter and spring periods, while the summer and fall have slightly smaller underestimations of NH4+ wet deposition. The underestimation in NH4+ wet deposition is likely due in part to the poor temporal and spatial representation of ammonia (NH3 emissions, particularly those emissions associated with fertilizer applications and NH3 bi-directional exchange. The model performance for estimates of NO3 wet deposition are

  5. Vertically aligned carbon nanotube growth by pulsed laser deposition and thermal chemical vapor deposition methods

    International Nuclear Information System (INIS)

    Sohn, Jung Inn; Nam, Chunghee; Lee, Seonghoon

    2002-01-01

    We have grown vertically aligned carbon nanotubes on the various substrates such as a planar p-type Si(1 0 0) wafer, porous Si wafer, SiO 2 , Si 3 N 4 , Al 2 O 3 , and Cr by thermal chemical vapor deposition (CVD) at 800 deg.C, using C 2 H 2 gas as a carbon source and Fe catalyst films deposited by a pulsed laser on the substrates. The Fe films were deposited for 5 min by pulsed laser deposition (PLD). The advantage of Fe deposition by PLD over other deposition methods lies in the superior adhesion of Fe to a Si substrate due to high kinetic energies of the generated Fe species. Scanning electron microscopy (SEM) images show that vertically well-aligned carbon nanotubes are grown on Fe nanoparticles formed from the thermal annealing of the Fe film deposited by PLD on the various substrates. Atomic force microscopy (AFM) images show that the Fe film annealed at 800 deg.C is broken to Fe nanoparticles of 10-50 nm in size. We show that the appropriate density of Fe nanoparticles formed from the thermal annealing of the film deposited by PLD is crucial in growing vertically aligned carbon nanotubes. Using a PLD and a lift-off method, we developed the selective growth of carbon nanotubes on a patterned Fe-coated Si substrate

  6. Synthesis of CuS nanoparticles by a wet chemical route and their photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Pal, Mou; Mathews, N. R. [Universidad Nacional Autónoma de México, Instituto de Energías Renovables (Mexico); Sanchez-Mora, E.; Pal, U. [Instituto de Física, BUAP (Mexico); Paraguay-Delgado, F. [Centro de Investigación en Materiales Avanzados (CIMAV), Departamento de Materiales Nanoestructurados (Mexico); Mathew, X., E-mail: xm@ier.unam.mx [Universidad Nacional Autónoma de México, Instituto de Energías Renovables (Mexico)

    2015-07-15

    CuS nanoparticles (NPs) of few nanometers in size were prepared by a wet chemical method. The structural, compositional, and optical properties of the NPs were characterized by X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, micro Raman and Fourier transform infrared spectroscopy, N{sub 2} adsorption–desorption isotherms, and UV–Vis diffuse reflectance spectroscopy. The XRD pattern proved the presence of hexagonal phase of CuS particles which was further supported by Raman spectrum. The estimated band gap energy of 2.05 eV for the slightly sulfur-rich CuS NPs is relatively larger than that of bulk CuS (1.85 eV), indicating the small size effect. As-prepared NPs showed excellent photocatalytic activity for the degradation of methylene blue (MB) under visible light. The surface-bound OH{sup −} ions at the CuS nanostructures help adsorb MB molecules facilitating their degradation process under visible light illumination. The studies presented in this paper suggest that the synthesized CuS NPs are promising, efficient, stable, and visible-light-sensitive photocatalyst for the remediation of wastewater polluted by chemically stable azo dyes such as MB.

  7. Investigation of microstructure and mechanical properties of phosphocalcic bone substitute using the chemical wet method

    Science.gov (United States)

    Alimi, Latifa; Bahloul, Lynda; Azzi, Afef; Guerfi, Souad; Ismail, Fadhel; Chaoui, Kamel

    2018-05-01

    Selection of calcium phosphate base materials in reconstructive bone surgery is justified by the surprising similarities in chemical compositions with human bones. The closest to natural apatite material is the hydroxyapatite (HAp) which has a chemical composition based on calcium and phosphate (Ca10(PO4)6(OH)2). In this study, HAp is synthesized using the wet precipitation method from hydrated calcium chloride (CaCl2,12H2O) and di-sodium hydrogen phosphate di-hydrate (HNa2PO4,2H2O). The powder is calcinated at 900°C and 1200°C in order to compare with sintered condition at 1150°C. Vickers microhardness tests and X-ray diffraction analyzes are used for the characterization of the crystalline material. Mechanical properties (Hv, σe, σr, and KC) and the degree of crystallinity (Xc) are discussed according to heat treatment temperatures. Results indicate that heat treating the powder at 1200°C increased crystallinity up to 72%. At the same time, microhardness increased with temperature and even outmatched the sintered case at 1150°C. Fracture toughness is ameliorated with increasing heat treatment temperature by more than two folds.

  8. Oil sands development and its impact on atmospheric wet deposition of air pollutants to the Athabasca Oil Sands Region, Alberta, Canada

    International Nuclear Information System (INIS)

    Lynam, Mary M.; Dvonch, J. Timothy; Barres, James A.; Morishita, Masako; Legge, Allan; Percy, Kevin

    2015-01-01

    Characterization of air pollutant deposition resulting from Athabasca oil sands development is necessary to assess risk to humans and the environment. To investigate this we collected event-based wet deposition during a pilot study in 2010–2012 at the AMS 6 site 30 km from the nearest upgrading facility in Fort McMurray, AB, Canada. Sulfate, nitrate and ammonium deposition was (kg/ha) 1.96, 1.60 and 1.03, respectively. Trace element pollutant deposition ranged from 2 × 10"−"5 - 0.79 and exhibited the trend Hg < Se < As < Cd < Pb < Cu < Zn < S. Crustal element deposition ranged from 1.4 × 10"−"4 – 0.46 and had the trend: La < Ce < Sr < Mn < Al < Fe < Mg. S, Se and Hg demonstrated highest median enrichment factors (130–2020) suggesting emissions from oil sands development, urban activities and forest fires were deposited. High deposition of the elements Sr, Mn, Fe and Mg which are tracers for soil and crustal dust implies land-clearing, mining and hauling emissions greatly impacted surrounding human settlements and ecosystems. - Highlights: • Atmospheric event wet deposition was collected during a 21 month pilot study. • Major ion, anthropogenic and crustal element wet deposition was characterized. • Low precipitation depths attenuated major ion and anthropogenic element deposition. • Oil sands development, urban activities and forest fires contributed to deposition. - In the vicinity of oil sands, monitoring revealed that wet deposition of major ions (SO_4"2"−, NO_3"-, NH_4"+) was highest followed by S and Mg, the latter is a tracer for soil/crustal dust.

  9. Kinetics of chemical vapor deposition of boron on molybdenum

    International Nuclear Information System (INIS)

    Tanaka, W.; Nakaanishi, N.; Kato, E.

    1987-01-01

    Experimental rate data of chemical vapor deposition of boron by reduction of boron trichloride with hydrogen are analyzed to determine the reaction mechanism. The reaction orders with respect to the partial pressures of hydrogen and boron trichloride are one half and one third, respectively. It has been found that the outer layer of a deposited film is Mo/sub 2/B/sub 5/ and the inner layer is MoB by the use of X-ray diffraction and EPMA line analysis

  10. Carry-over of plant protection agents through wet deposition on the Kleine Feldberg/Taunus; Eintrag von Pflanzenschutzmitteln durch nasse Deposition auf dem Kleinen Feldberg/Taunus

    Energy Technology Data Exchange (ETDEWEB)

    Gath, B. [Zentrum fuer Umweltforschung der Johann Wolfgang Goethe-Universitaet, Frankfurt am Main (Germany); Jaeschke, W. [Zentrum fuer Umweltforschung der Johann Wolfgang Goethe-Universitaet, Frankfurt am Main (Germany); Kubiak, R. [Landes-Lehr- und Forschungsanstalt fuer Landwirtschaft, Weinbau und Gartenbau, Neustadt an der Weinstrasse (Germany); Ricker, I. [Battelle Europe Battelle-Institut e.V., Frankfurt am Main (Germany); Schmider, F. [BASF AG, Landwirtschaftliche Versuchsstation, Limburgerhof (Germany); Zietz, E. [Battelle Europe Battelle-Institut e.V., Frankfurt am Main (Germany)

    1993-11-01

    On the Feldberg and at two more sites precipitation samples were taken and analysed for selected pesticides (Lindan, Isoproturon, Triadimenol, Pirimicarb, Parathion-ethyl and atrazine). Bulk samplers (acc. to Daemmgen) were used in 14-day intervals. At two stations wet-only samplers were used in addition to the bulk samplers. Parathion-ethyl, Pirimicarb and Triadimenol were only found in single cases only. Distinct annual curves could be established for atrazin and isoproturon, they are shown in desposition charts. Only Lindan was detectable all year round. Concentrations were between 3 and 300 ng l{sup {minus}1}. Annual curves show good correlation with application periods of the individual substances. In general the annual mean value of the concentrations are below 50 ng l{sup {minus}1}. The share of dry deposition depends on substance and weather and account roughly for 10-20% of total deposition. (orig./EW) [Deutsch] Auf dem Feldberg sowie an zwei weiteren Messstandorten wurden parallel Niederschlagsproben genommen und auf ausgewaehlte Pestizide (Lindan, Isoproturon, Triadimenol, Pirimicarb, Parathion-ethyl und Atrazin) untersucht. Die Probenahme erfolgte in bulk-Sammlern nach Daemmgen in 14-Tage Intervallen. An zwei Stationen wurden parallel zu den bulk-Sammlern auch wet-only Sammler betrieben. Parathion-ethyl, Pirimicarb und Triadimenol konnten nur vereinzelt nachgewiesen werden. Von Atrazin und Isoproturon wurden ausgepraegte Jahresgaenge ermittelt und in Depositionsgraphiken dargestellt. Lediglich Lindan war nahezu das ganze Jahr ueber nachweisbar. Die gemessenen Konzentrationen lagen zwischen 3 und 300 ng 1{sup -1}. Die dargestellten Jahresgaenge korrelieren gut mit den jeweiligen Anwendungszeitraeumen der einzelnen Substanzen. Insgesamt liegen die gemessenen Konzentrationen im Jahresmittel unter 50 ngl{sup -1}. Der Beitrag der trockenen Deposition ist substanz- und wetterabhaengig und macht etwa 10-20% der Gesamtdeposition aus. (orig.)

  11. How deposition parameters control growth dynamics of nc-Si deposited by hot-wire chemical vapor deposition

    International Nuclear Information System (INIS)

    Moutinho, H.R.; To, B.; Jiang, C.-S.; Xu, Y.; Nelson, B.P.; Teplin, C.W.; Jones, K.M.; Perkins, J.; Al-Jassim, M.M.

    2006-01-01

    We studied the growth of silicon films deposited by hot-wire chemical vapor deposition under different values of filament current, substrate temperature, and hydrogen dilution ratio. The physical and electrical properties of the films were studied by Raman spectroscopy, x-ray diffraction, atomic force microscopy, conductive-atomic force microscopy, and transmission electron microscopy. There is an interdependence of the growth parameters, and films grown with different parameters can have similar structures. We discuss why this interdependence occurs and how it influences the properties of the deposited films, as well as the deposition rate. In general, the films have a complex structure, with a mixture of amorphous (220)-oriented crystalline and nanocrystalline phases present in most cases. The amount of each phase can be controlled by the variation of one or more of the growth parameters at a time

  12. Analysis of Wetting and Contact Angle Hysteresis on Chemically Patterned Surfaces

    KAUST Repository

    Xu, Xianmin; Wang, Xiaoping

    2011-01-01

    Wetting and contact angle hysteresis on chemically patterned surfaces in two dimensionsare analyzed from a stationary phase-field model for immiscible two phase fluids. We first study the sharp-interface limit of the model by the method of matched asymptotic expansions. We then justify the results rigorously by the γ-convergence theory for the related variational problem and study the properties of the limiting minimizers. The results also provide a clear geometric picture of the equilibrium configuration of the interface. This enables us to explicitly calculate the total surface energy for the two phase systems on chemically patterned surfaces with simple geometries, namely the two phase flow in a channel and the drop spreading. By considering the quasi-staticmotion of the interface described by the change of volume (or volume fraction), we can follow the change-of-energy landscape which also reveals the mechanism for the stick-slip motion of the interface and contact angle hysteresis on the chemically patterned surfaces. As the interface passes throughpatterned surfaces, we observe not only stick-slip of the interface and switching of the contact angles but also the hysteresis of contact point and contact angle. Furthermore, as the size of the patternde creases to zero, the stick-slip becomes weaker but the hysteresis becomes stronger in the sense that one observes either the advancing contact angle or the receding contact angle (when the interface ismoving in the opposite direction) without the switching in between. © 2011 Society for Industrial and Applied Mathematics.

  13. The versatility of hot-filament activated chemical vapor deposition

    International Nuclear Information System (INIS)

    Schaefer, Lothar; Hoefer, Markus; Kroeger, Roland

    2006-01-01

    In the field of activated chemical vapor deposition (CVD) of polycrystalline diamond films, hot-filament activation (HF-CVD) is widely used for applications where large deposition areas are needed or three-dimensional substrates have to be coated. We have developed processes for the deposition of conductive, boron-doped diamond films as well as for tribological crystalline diamond coatings on deposition areas up to 50 cm x 100 cm. Such multi-filament processes are used to produce diamond electrodes for advanced electrochemical processes or large batches of diamond-coated tools and parts, respectively. These processes demonstrate the high degree of uniformity and reproducibility of hot-filament CVD. The usability of hot-filament CVD for diamond deposition on three-dimensional substrates is well known for CVD diamond shaft tools. We also develop interior diamond coatings for drawing dies, nozzles, and thread guides. Hot-filament CVD also enables the deposition of diamond film modifications with tailored properties. In order to adjust the surface topography to specific applications, we apply processes for smooth, fine-grained or textured diamond films for cutting tools and tribological applications. Rough diamond is employed for grinding applications. Multilayers of fine-grained and coarse-grained diamond have been developed, showing increased shock resistance due to reduced crack propagation. Hot-filament CVD is also used for in situ deposition of carbide coatings and diamond-carbide composites, and the deposition of non-diamond, silicon-based films. These coatings are suitable as diffusion barriers and are also applied for adhesion and stress engineering and for semiconductor applications, respectively

  14. Determination of dry and wet deposition in forest areas in the Federal Republic of Germany. Final report. Pt. A. Feststellung der Schadstoffbelastung von Waldgebieten in der Bundesrepublik Deutschland durch trockene und nasse Deposition. Abschlussbericht. T. A

    Energy Technology Data Exchange (ETDEWEB)

    Georgii, H.W.; Grosch, S.; Schmitt, G.

    1986-08-01

    A network of 7 forest stations was maintained during the period of 1982-1985. The investigation included the evaluation of the dry and wet deposition of the following compounds: H/sup +/, SO/sub 4//sup 2-/, NO/sub 3//sup -/, Cl/sup -/, Pb, Mn, Fe, Cd, Na, K, Ca and Mg. During a certain period of time also the compounds Al, Cu, Cr and NH/sub 4//sup +/ were analyzed. Measurements of the aerosols and bulk deposition in different levels of the forest stands give information about the influence of spruce stands on the distribution of deposition. Detailed investigation on the composition of fogwater show the importance of fog with respect to the atmospheric input into forest ecosystems. Investigations of ozone at stations in the Taunus area show increasing concentrations with increasing altitudes. The sudden release of accumulated pollutants in snow appearing in the spring time during the thaw is shown. Sequential rain sampling at stations at different altitudes gives information about the contribution of 'rain-out' and 'wash-out'-processes with respect of the chemical composition of the rain. (orig.) With 55 refs., 20 tabs., 99 figs.

  15. Correlation of film density and wet etch rate in hydrofluoric acid of plasma enhanced atomic layer deposited silicon nitride

    Energy Technology Data Exchange (ETDEWEB)

    Provine, J., E-mail: jprovine@stanford.edu; Schindler, Peter; Kim, Yongmin; Walch, Steve P.; Kim, Hyo Jin [Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Kim, Ki-Hyun [Manufacturing Technology Center, Samsung Electronics, Suwon, Gyeonggi-Do (Korea, Republic of); Prinz, Fritz B. [Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States)

    2016-06-15

    The continued scaling in transistors and memory elements has necessitated the development of atomic layer deposition (ALD) of silicon nitride (SiN{sub x}), particularly for use a low k dielectric spacer. One of the key material properties needed for SiN{sub x} films is a low wet etch rate (WER) in hydrofluoric (HF) acid. In this work, we report on the evaluation of multiple precursors for plasma enhanced atomic layer deposition (PEALD) of SiN{sub x} and evaluate the film’s WER in 100:1 dilutions of HF in H{sub 2}O. The remote plasma capability available in PEALD, enabled controlling the density of the SiN{sub x} film. Namely, prolonged plasma exposure made films denser which corresponded to lower WER in a systematic fashion. We determined that there is a strong correlation between WER and the density of the film that extends across multiple precursors, PEALD reactors, and a variety of process conditions. Limiting all steps in the deposition to a maximum temperature of 350 °C, it was shown to be possible to achieve a WER in PEALD SiN{sub x} of 6.1 Å/min, which is similar to WER of SiN{sub x} from LPCVD reactions at 850 °C.

  16. Chemical bath ZnSe thin films: deposition and characterisation

    Science.gov (United States)

    Lokhande, C. D.; Patil, P. S.; Ennaoui, A.; Tributsch, H.

    1998-01-01

    The zinc selenide (ZnSe) thin films have been deposited by a simple and inexpensive chemical bath deposition (CBD) method. The selenourea was used as a selenide ion source. The ZnSe films have been characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDAX), Rutherford back scattering (RBS), and optical absorption. The as-deposited ZnSe films on various substrates are found to be amorphous and contain O2 and N2 in addition to Zn and Se. The optical band gap of the film is estimated to be 2.9 eV. The films are photoactive as evidenced by time resolved microwave conductivity (TRMC).

  17. Structural characterization of chemically deposited PbS thin films

    International Nuclear Information System (INIS)

    Fernandez-Lima, F.A.; Gonzalez-Alfaro, Y.; Larramendi, E.M.; Fonseca Filho, H.D.; Maia da Costa, M.E.H.; Freire, F.L.; Prioli, R.; Avillez, R.R. de; Silveira, E.F. da; Calzadilla, O.; Melo, O. de; Pedrero, E.; Hernandez, E.

    2007-01-01

    Polycrystalline thin films of lead sulfide (PbS) grown using substrate colloidal coating chemical bath depositions were characterized by RBS, XPS, AFM and GIXRD techniques. The films were grown on glass substrates previously coated with PbS colloidal particles in a polyvinyl alcohol solution. The PbS films obtained with the inclusion of the polymer showed non-oxygen-containing organic contamination. All samples maintained the Pb:S 1:1 stoichiometry throughout the film. The amount of effective nucleation centers and the mean grain size have being controlled by the substrate colloidal coating. The analysis of the polycrystalline PbS films showed that a preferable (1 0 0) lattice plane orientation parallel to the substrate surface can be obtained using a substrate colloidal coating chemical bath deposition, and the orientation increases when a layer of colloid is initially dried on the substrate

  18. Physical properties of chemical vapour deposited nanostructured carbon thin films

    International Nuclear Information System (INIS)

    Mahadik, D.B.; Shinde, S.S.; Bhosale, C.H.; Rajpure, K.Y.

    2011-01-01

    Research highlights: In the present paper, nanostructured carbon films are grown using a natural precursor 'turpentine oil (C 10 H 16 )' as a carbon source in the simple thermal chemical vapour deposition method. The influence of substrate surface topography (viz. stainless steel, fluorine doped tin oxide coated quartz) and temperature on the evolution of carbon allotropes surfaces topography/microstructural and structural properties are investigated and discussed. - Abstract: A simple thermal chemical vapour deposition technique is employed for the deposition of carbon films by pyrolysing the natural precursor 'turpentine oil' on to the stainless steel (SS) and FTO coated quartz substrates at higher temperatures (700-1100 deg. C). In this work, we have studied the influence of substrate and deposition temperature on the evolution of structural and morphological properties of nanostructured carbon films. The films were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), contact angle measurements, Fourier transform infrared (FTIR) and Raman spectroscopy techniques. XRD study reveals that the films are polycrystalline exhibiting hexagonal and face-centered cubic structures on SS and FTO coated glass substrates respectively. SEM images show the porous and agglomerated surface of the films. Deposited carbon films show the hydrophobic nature. FTIR study displays C-H and O-H stretching vibration modes in the films. Raman analysis shows that, high ID/IG for FTO substrate confirms the dominance of sp 3 bonds with diamond phase and less for SS shows graphitization effect with dominant sp 2 bonds. It reveals the difference in local microstructure of carbon deposits leading to variation in contact angle and hardness, which is ascribed to difference in the packing density of carbon films, as observed also by Raman.

  19. Determination of chemical oxygen demand (COD) using an alternative wet chemical method free of mercury and dichromate.

    Science.gov (United States)

    Kolb, Marit; Bahadir, Müfit; Teichgräber, Burkhard

    2017-10-01

    Worldwide, the standard methods for the determination of the important wastewater parameter chemical oxygen demand (COD) are still based on the use of the hazardous chemicals, mercury sulfate and chromium(VI). However, due to their properties they are meanwhile classified as "priority pollutants" and shall be phased out or banned in the frame of REACH (current European Chemical Law: Registration, Evaluation, Authorization and restriction of Chemicals) by the European Union. Hence, a new wet-chemical method free of mercury and chromium(VI) was developed. Manganese(III) was used as oxidant and silver nitrate for the removal of chloride ions. The quantification was performed by back titration of manganese(III) with iron(II) as done in the standard method. In order to minimize losses of organic substances during the precipitation of silver chloride, suspended and colloid organic matter had to be separated by precipitation of aluminum hydroxide in a first step. In these cases, two fractions, one of the suspended and colloid matters and a second of the dissolved organic substances, are prepared and oxidized separately. The method was tested with potassium hydrogen phthalate (KHP) as conventional COD reference substance and different types of wastewater samples. The oxidation of KHP was reproducible in a COD range of 20-500 mg/L with a mean recovery rate of 88.7% in comparison to the standard COD method (DIN 38409-41). Also in presence of 1000 mg/L chloride a recovery rate of 84.1% was reached. For a series of industrial and municipal wastewater samples a high correlation (R 2  = 0.9935) to the standard method with a mean recovery rate of 78.1% (±5.2%) was determined. Even though the results of the new method are not 100% of the standard method, its high correlation to the standard method and reproducibility offers an environmentally benign alternative method with no need to purchase new laboratory equipment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Research on chemical vapor deposition processes for advanced ceramic coatings

    Science.gov (United States)

    Rosner, Daniel E.

    1993-01-01

    Our interdisciplinary background and fundamentally-oriented studies of the laws governing multi-component chemical vapor deposition (VD), particle deposition (PD), and their interactions, put the Yale University HTCRE Laboratory in a unique position to significantly advance the 'state-of-the-art' of chemical vapor deposition (CVD) R&D. With NASA-Lewis RC financial support, we initiated a program in March of 1988 that has led to the advances described in this report (Section 2) in predicting chemical vapor transport in high temperature systems relevant to the fabrication of refractory ceramic coatings for turbine engine components. This Final Report covers our principal results and activities for the total NASA grant of $190,000. over the 4.67 year period: 1 March 1988-1 November 1992. Since our methods and the technical details are contained in the publications listed (9 Abstracts are given as Appendices) our emphasis here is on broad conclusions/implications and administrative data, including personnel, talks, interactions with industry, and some known applications of our work.

  1. Geochemistry and hydrology of a small catchment: fogs as an important part of the wet deposition

    Czech Academy of Sciences Publication Activity Database

    Tesař, Miroslav; Fottová, D.; Šír, Miloslav; Fišák, Jaroslav

    2010-01-01

    Roč. 39, 1-2 (2010), s. 389-390 ISSN 0324-0894. [Congress of the Carpathian-Balkan Geological Association /19./. 23.09.2010-26.09.2010, Thessaloniki] R&D Projects: GA ČR GA205/09/1918 Institutional research plan: CEZ:AV0Z20600510; CEZ:AV0Z30420517 Keywords : fog water deposition * chemistry * fog water sampler Subject RIV: DA - Hydrology ; Limnology

  2. Confined high-pressure chemical deposition of hydrogenated amorphous silicon.

    Science.gov (United States)

    Baril, Neil F; He, Rongrui; Day, Todd D; Sparks, Justin R; Keshavarzi, Banafsheh; Krishnamurthi, Mahesh; Borhan, Ali; Gopalan, Venkatraman; Peacock, Anna C; Healy, Noel; Sazio, Pier J A; Badding, John V

    2012-01-11

    Hydrogenated amorphous silicon (a-Si:H) is one of the most technologically important semiconductors. The challenge in producing it from SiH(4) precursor is to overcome a significant kinetic barrier to decomposition at a low enough temperature to allow for hydrogen incorporation into a deposited film. The use of high precursor concentrations is one possible means to increase reaction rates at low enough temperatures, but in conventional reactors such an approach produces large numbers of homogeneously nucleated particles in the gas phase, rather than the desired heterogeneous deposition on a surface. We report that deposition in confined micro-/nanoreactors overcomes this difficulty, allowing for the use of silane concentrations many orders of magnitude higher than conventionally employed while still realizing well-developed films. a-Si:H micro-/nanowires can be deposited in this way in extreme aspect ratio, small-diameter optical fiber capillary templates. The semiconductor materials deposited have ~0.5 atom% hydrogen with passivated dangling bonds and good electronic properties. They should be suitable for a wide range of photonic and electronic applications such as nonlinear optical fibers and solar cells. © 2011 American Chemical Society

  3. Trace elements and rare earth elements in wet deposition of Lijiang, Mt. Yulong region, southeastern edge of the Tibetan Plateau.

    Science.gov (United States)

    Guo, Junming; Kang, Shichang; Huang, Jie; Sillanpää, Mika; Niu, Hewen; Sun, Xuejun; He, Yuanqing; Wang, Shijing; Tripathee, Lekhendra

    2017-02-01

    In order to investigate the compositions and wet deposition fluxes of trace elements and rare earth elements (REEs) in the precipitation of the southeastern edge of the Tibetan Plateau, 38 precipitation samples were collected from March to August in 2012 in an urban site of Lijiang city in the Mt. Yulong region. The concentrations of most trace elements and REEs were higher during the non-monsoon season than during the monsoon season, indicating that the lower concentrations of trace elements and REEs observed during monsoon had been influenced by the dilution effect of increased precipitation. The concentrations of trace elements in the precipitation of Lijiang city were slightly higher than those observed in remote sites of the Tibetan Plateau but much lower than those observed in the metropolises of China, indicating that the atmospheric environment of Lijiang city was less influenced by anthropogenic emissions, and, as a consequence, the air quality was still relatively good. However, the results of enrichment factor and principal component analysis revealed that some anthropogenic activities (e.g., the increasing traffic emissions from the rapid development of tourism) were most likely important contributors to trace elements, while the regional/local crustal sources rather than anthropogenic activities were the predominant contributors to the REEs in the wet deposition of Lijiang city. Our study was relevant not only for assessing the current status of the atmospheric environment in the Mt. Yulong region, but also for specific management actions to be implemented for the control of atmospheric inputs and the health of the environment for the future. Copyright © 2016. Published by Elsevier B.V.

  4. CuO nanostructures on copper foil by a simple wet chemical route at room temperature

    International Nuclear Information System (INIS)

    Jana, S.; Das, S.; Das, N.S.; Chattopadhyay, K.K.

    2010-01-01

    Uniform CuO nanostructures have been synthesized on copper foil substrates by oxidation of Cu in alkaline condition by a simple wet chemical route at room temperature. By controlling the alkaline condition (pH value) different CuO nanostructures like nanoneedles, self-assembled nanoflowers and staking of flake-like structures were achieved. The phase formation and the composition of the films were characterized by X-ray diffraction and energy dispersive analysis of X-ray studies. X-ray photoelectron spectroscopic studies indicated that the samples were composed of CuO. The morphologies of the films were investigated by scanning electron microscopy. A possible growth mechanism is also proposed here. Band gap energies of the nanostructures were determined from the optical reflectance spectra. The different CuO nanostructures showed good electron field emission properties with turn-on fields in the range 6-11.3 V μm -1 . The field emission current was significantly affected by the morphologies of the CuO films.

  5. Bioceramics synthesis of hydroxyapatite from red snapper fish scales biowaste using wet chemical precipitation route

    Science.gov (United States)

    Ulfyana, D.; Anugroho, F.; Sumarlan, S. H.; Wibisono, Y.

    2018-03-01

    Fish scales biowaste contain high collagens and calcium phosphates, therefore have considerable potential as raw material for value-added biomaterial such as hydroxyapatite (HAp). HAp is the main constituent component of hard tissue such as bone and teeth in the human body and is known as bioceramic materials. In this work, wet chemical precipitation method was used to syntesize HAp from Red Snapper Fish (Lutjanus campechanus) Scales. Two variations of calcination temperatures of 600°C (FHAp1) and 800°C (FHAp2) were conducted for 5 hours. The results showed calcium content from biowaste of red snapper fish scale was 83.62%. FTIR result shows that PO4 3-, OH-, and CO3 2- functional groups presence as indicates the formation of HAp. XRD result showed the degree of crystallinity for FHAp1 and FHAp2 were 75.52% and 79.20%, respectively. The degree of crystallinity is in accordance with ISO 13779-2:2000 standard in which the minimum degree of crystallinity of hydroxyapatite used for biomedical materials is 45%. Finally, Particle Size Analyzer (PSA) results show that the particle size distribution is evenly distributed, with the size of micro-scale hydroxyapatite particles, ranging from 5.76 μm to 132.64 μm.

  6. Wet chemical passivation of YBa2Cu3O(7-x)

    Science.gov (United States)

    Vasquez, R. P.; Hunt, B. D.; Foote, M. C.

    1990-01-01

    Wet chemical techniques are described for treatment of YBa2Cu3O(7-x) surfaces, which result in the formation of native compounds known to have little or no reactivity to water. Suitable native compounds include CuI, BaSO4, CuS, Cu2S, YF3, and the oxalates. Formation of surface layers in which these nonreactive native compounds are major constituents is verified with X-ray photoelectron spectroscopy (XPS) measurements on YBa2Cu3O(7-x) films treated with dilute solutions of HI, H2SO4, Na2S, HF, or H2C2O4. No significant changes are observed in the XPS spectra when the sulfide, sulfate, or oxalate films are dipped in water, while the iodide and fluoride films show evidence of reaction with water. X-ray diffraction measurements show that the superconducting phase is absent in the sulfide film, but is unaffected by the oxalate and sulfate treatments.

  7. Tailoring Novel PTFE Surface Properties: Promoting Cell Adhesion and Antifouling Properties via a Wet Chemical Approach.

    Science.gov (United States)

    Gabriel, Matthias; Niederer, Kerstin; Becker, Marc; Raynaud, Christophe Michel; Vahl, Christian-Friedrich; Frey, Holger

    2016-05-18

    Many biomaterials used for tissue engineering applications lack cell-adhesiveness and, in addition, are prone to nonspecific adsorption of proteins. This is especially important for blood-contacting devices such as vascular grafts and valves where appropriate surface properties should inhibit the initial attachment of platelets and promote endothelial cell colonization. As a consequence, the long-term outcome of the implants would be improved and the need for anticoagulation therapy could be reduced or even abolished. Polytetrafluoroethylene (PTFE), a frequently used polymer for various medical applications, was wet-chemically activated and subsequently modified by grafting the endothelial cell (EC) specific peptide arginine-glutamic acid-aspartic acid-valine (REDV) using a bifunctional polyethylene glycol (PEG)-spacer (known to reduce platelet and nonspecific protein adhesion). Modified and control surfaces were both evaluated in terms of EC adhesion, colonization, and the attachment of platelets. In addition, samples underwent bacterial challenges. The results strongly suggested that PEG-mediated peptide immobilization renders PTFE an excellent substrate for cellular growth while simultaneously endowing the material with antifouling properties.

  8. Zintl Clusters as Wet-Chemical Precursors for Germanium Nanomorphologies with Tunable Composition.

    Science.gov (United States)

    Bentlohner, Manuel M; Waibel, Markus; Zeller, Patrick; Sarkar, Kuhu; Müller-Buschbaum, Peter; Fattakhova-Rohlfing, Dina; Fässler, Thomas F

    2016-02-12

    [Ge9](4-) Zintl clusters are used as soluble germanium source for a bottom-up fabrication of Ge nanomorphologies such as inverse opal structures with tunable composition. The method is based on the assembly and oxidation of [Ge9 ](4-) clusters in a template mold using SiCl4 , GeCl4 , and PCl3 leading to Si and P-containing Ge phases as shown by X-ray diffraction, Raman spectroscopy, and energy-dispersive X-ray analysis. [Ge9](4-) clusters are retained using ethylenediamine (en) as a transfer medium to a mold after removal of the solvent if water is thoroughly excluded, but are oxidized to amorphous Ge in presence of water traces. (1)H NMR spectroscopy reveals the oxidative deprotonation of en by [Ge9](4-). Subsequent annealing leads to crystalline Ge. As an example for wet-chemical synthesis of complex Ge nanomorphologies, we describe the fabrication of undoped and P-doped inverse opal-structured Ge films with a rather low oxygen contents. The morphology of the films with regular volume porosity is characterized by SEM, TEM, and grazing incidence small-angle X-ray scattering. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Wet-chemical etching of atom probe tips for artefact free analyses of nanoscaled semiconductor structures.

    Science.gov (United States)

    Melkonyan, D; Fleischmann, C; Veloso, A; Franquet, A; Bogdanowicz, J; Morris, R J H; Vandervorst, W

    2018-03-01

    We introduce an innovative specimen preparation method employing the selectivity of a wet-chemical etching step to improve data quality and success rates in the atom probe analysis of contemporary semiconductor devices. Firstly, on the example of an SiGe fin embedded in SiO 2 we demonstrate how the selective removal of SiO 2 from the final APT specimen significantly improves accuracy and reliability of the reconstructed data. With the oxide removal, we eliminate the origin of shape artefacts, i.e. the formation of a non-hemispherical tip shape, that are typically observed in the reconstructed volume of complex systems. Secondly, using the same approach, we increase success rates to ∼90% for the damage-free, 3D site-specific localization of short (250 nm), vertical Si nanowires at the specimen apex. The impact of the abrupt emitter radius change that is introduced by this specimen preparation method is evaluated as being minor using field evaporation simulation and comparison of different reconstruction schemes. The Ge content within the SiGe fin as well as the 3D boron distribution in the Si NW as resolved by atom probe analysis are in good agreement with TEM/EDS and ToF-SIMS analysis, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Concurrent production of biodiesel and chemicals through wet in situ transesterification of microalgae.

    Science.gov (United States)

    Im, Hanjin; Kim, Bora; Lee, Jae W

    2015-10-01

    This work addresses an unprecedented way of co-producing biodiesel (FAEE) and valuable chemicals of ethyl levulinate (EL), ethyl formate (EF) and diethyl ether (DEE) from wet in situ transesterification of microalgae. EL, EF, and DEE were significantly produced up to 23.1%, 10.3%, and 52.1% of the maximum FAEE mass with the FAEE yield higher than 90% at 125 °C. Experiments to elucidate a detailed route of EL and EF synthesis were fulfilled and it was found that its main route to the production of EL and EF was the acid hydrolysis of algal cells and esterification with ethanol. To investigate the effect of reaction variables on the products yields, comprehensive experiments were carried out with varying temperatures, solvent and alcohol volumes, moisture contents and catalyst amounts. Coproduction of DEE, EL, EF and FAEE can contribute to elevating the economic feasibility of microalgae-based biodiesel supply chain. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Effects of etchants in the transfer of chemical vapor deposited graphene

    Science.gov (United States)

    Wang, M.; Yang, E. H.; Vajtai, R.; Kono, J.; Ajayan, P. M.

    2018-05-01

    The quality of graphene can be strongly modified during the transfer process following chemical vapor deposition (CVD) growth. Here, we transferred CVD-grown graphene from a copper foil to a SiO2/Si substrate using wet etching with four different etchants: HNO3, FeCl3, (NH4)2S2O8, and a commercial copper etchant. We then compared the quality of graphene after the transfer process in terms of surface modifications, pollutions (residues and contaminations), and electrical properties (mobility and density). Our tests and analyses showed that the commercial copper etchant provides the best structural integrity, the least amount of residues, and the smallest doping carrier concentration.

  12. Remote plasma-enhanced metalorganic chemical vapor deposition of aluminum oxide thin films

    NARCIS (Netherlands)

    Volintiru, I.; Creatore, M.; Hemmen, van J.L.; Sanden, van de M.C.M.

    2008-01-01

    Aluminum oxide films were deposited using remote plasma-enhanced metalorganic chemical vapor deposition from oxygen/trimethylaluminum mixtures. Initial studies by in situ spectroscopic ellipsometry demonstrated that the aluminum oxide films deposited at temperatures

  13. Deposition characteristics of titanium coating deposited on SiC fiber by cold-wall chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Xian, E-mail: luo_shenfan@hotmail.com; Wu, Shuai; Yang, Yan-qing; Jin, Na; Liu, Shuai; Huang, Bin

    2016-12-01

    The deposition characteristics of titanium coating on SiC fiber using TiCl{sub 4}-H{sub 2}-Ar gas mixture in a cold-wall chemical vapor deposition were studied by the combination of thermodynamic analysis and experimental studies. The thermodynamic analysis of the reactions in the TiCl{sub 4}-H{sub 2}-Ar system indicates that TiCl{sub 4} transforms to titanium as the following paths: TiCl{sub 4} → TiCl{sub 3} → Ti, or TiCl{sub 4} → TiCl{sub 3} → TiCl{sub 2} → Ti. The experimental results show that typical deposited coating contains two distinct layers: a TiC reaction layer close to SiC fiber and titanium coating which has an atomic percentage of titanium more than 70% and that of carbon lower than 30%. The results illustrate that a carbon diffusion barrier coating needs to be deposited if pure titanium is to be prepared. The deposition rate increases with the increase of temperature, but higher temperature has a negative effect on the surface uniformity of titanium coating. In addition, appropriate argon gas flow rate has a positive effect on smoothing the surface morphology of the coating. - Highlights: • Both thermodynamic analysis and experimental studies were adopted in this work. • The transformation paths of TiCl{sub 4} to Ti is: TiCl{sub 4} → TiCl{sub 3} → Ti, or TiCl{sub 4} → TiCl{sub 3} → TiCl{sub 2} → Ti. • Typical deposited Ti coating on SiC fiber contained two distinct layers. • Deposition temperature is important on deposition rate and morphologies. • Appropriate argon gas flow rate has a positive effect on smoothing of the coating.

  14. Radionuclide ratios in wet and dry deposition samples from June 1976 through December 1977

    International Nuclear Information System (INIS)

    Gavini, M.B.

    1978-01-01

    238 Pu, 239 Pu and 137 Cs in rain and dry fallout and 90 Sr in rain samples were measured at Woods Hole, Massachusetts, from June 1976 through December 1977. The dry fallout was estimated to be about 7.8% of the total deposition of 239 Pu and 137 Cs. 239 Pu/ 137 Cs ratios, almost constant at about 0.011 in rain or dry fallout, February through December 1977, suggested that fractionation between the refractory and volatile radionuclides is insignificant in stratospheric fallout. This supports the idea of regional homogeneity of radionuclide ratios in fallout. (Auth.)

  15. Chemical bath deposition of CdS thin films doped with Zn and Cu

    Indian Academy of Sciences (India)

    Abstract. Zn- and Cu-doped CdS thin films were deposited onto glass substrates by the chemical bath technique. ... Cadmium sulfide; chemical bath deposition; doping; optical window. 1. ..... at low temperature (10 K), finding similar trends than.

  16. Wet-chemical passivation of InAs: toward surfaces with high stability and low toxicity.

    Science.gov (United States)

    Jewett, Scott A; Ivanisevic, Albena

    2012-09-18

    In a variety of applications where the electronic and optical characteristics of traditional, siliconbased materials are inadequate, recently researchers have employed semiconductors made from combinations of group III and V elements such as InAs. InAs has a narrow band gap and very high electron mobility in the near-surface region, which makes it an attractive material for high performance transistors, optical applications, and chemical sensing. However, silicon-based materials remain the top semiconductors of choice for biological applications, in part because of their relatively low toxicity. In contrast to silicon, InAs forms an unstable oxide layer under ambient conditions, which can corrode over time and leach toxic indium and arsenic components. To make InAs more attractive for biological applications, researchers have investigated passivation, chemical and electronic stabilization, of the surface by adlayer adsorption. Because of the simplicity, low cost, and flexibility in the type of passivating molecule used, many researchers are currently exploring wet-chemical methods of passivation. This Account summarizes much of the recent work on the chemical passivation of InAs with a particular focus on the chemical stability of the surface and prevention of oxide regrowth. We review the various methods of surface preparation and discuss how crystal orientation affects the chemical properties of the surface. The correct etching of InAs is critical as researchers prepare the surface for subsequent adlayer adsorption. HCl etchants combined with a postetch annealing step allow the tuning of the chemical properties in the near-surface region to either arsenic- or indium-rich environments. Bromine etchants create indium-rich surfaces and do not require annealing after etching; however, bromine etchants are harsh and potentially destructive to the surface. The simultaneous use of NH(4)OH etchants with passivating molecules prevents contact with ambient air that can

  17. Short review on chemical bath deposition of thin film and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Mugle, Dhananjay, E-mail: dhananjayforu@gmail.com; Jadhav, Ghanshyam, E-mail: ghjadhav@rediffmail.com [Depertment of Physics, Shri Chhatrapati Shivaji College, Omerga-413606 (India)

    2016-05-06

    This reviews the theory of early growth of the thin film using chemical deposition methods. In particular, it critically reviews the chemical bath deposition (CBD) method for preparation of thin films. The different techniques used for characterizations of the chemically films such as X-ray diffractometer (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Electrical conductivity and Energy Dispersive Spectroscopy (EDS) are discussed. Survey shows the physical and chemical properties solely depend upon the time of deposition, temperature of deposition.

  18. Optimization of solar cell performance using atmospheric pressure chemical vapour deposition deposited TCOs

    Czech Academy of Sciences Publication Activity Database

    Yates, H.M.; Evans, P.; Sheel, D.W.; Hodgkinson, J.L.; Sheel, P.; Dagkaldiran, U.; Gordijn, A.; Finger, F.; Remeš, Zdeněk; Vaněček, Milan

    2009-01-01

    Roč. 25, č. 8 (2009), s. 789-796 ISSN 1938-5862. [International Chemical Vapor Deposition Symposium (CVD-XVII) /17./. Wien, 04.10.2009-09.10.2009] Grant - others:European Community(XE) Project (STREP) of the 6. FP Institutional research plan: CEZ:AV0Z10100521 Keywords : solar cells * TCO * CVD Subject RIV: BM - Solid Matter Physics ; Magnetism

  19. Size distribution of atmospheric Pb and 210Pb in rural New Jersey: implications for wet and dry deposition

    International Nuclear Information System (INIS)

    Knuth, R.H.; Knutson, E.O.; Feely, H.W.; Volchok, H.L.

    1983-01-01

    High volume cascade impactor samples taken during spring, 1980, at the Chester sampling station in northern New Jersey showed a small but persistent difference in the size distributions of Pb and 210 Pb. On the average, 69% of Pb was below 0.58 μm and 12% was above 3.45 μm. For 210 Pb, the corresponding figures were 71% and 2.8%. These 210 Pb data indicate larger particles than found in Colorado, but smaller than those found over the Mediterranean Sea. The average air concentrations for the two species were 111 ng/m 3 (Pb) and 10.9 fCi/m 3 ( 210 Pb), in good agreement with other reported results for rural northeast areas. Experimental results imply a factor of three difference in dry deposition velocity between the two species, providing a qualitative explanation of a previously observed difference in wet/dry deposition of the two species. 19 references, 1 figure, 6 tables

  20. Wet deposition and soil content of Beryllium - 7 in a micro-watershed of Minas Gerais (Brazil).

    Science.gov (United States)

    Esquivel L, Alexander D; Moreira, Rubens M; Monteiro, Roberto Pellacani G; Dos Santos, Anômora A Rochido; Juri Ayub, Jimena; Valladares, Diego L

    2017-04-01

    Beryllium-7 ( 7 Be) is a natural radionuclide of cosmogenic origin, normally used as a tracer for several environmental processes; such as soil redistribution, sediment source discrimination, atmospheric mass transport, and trace metal scavenging from the atmosphere. In this research the content of 7 Be in soil, its seasonal variation throughout the year and its relationship with the rainfall regime in the Mato Frio creek micro-watershed was investigated, to assess its potential use in estimating soil erosion. The 7 Be content in soil shows a marked variation throughout the year. Minimum 7 Be values were observed in the dry season (from April to September) and were between 7 and 14 times higher in the rainy season (from October to March). The seasonal oscillations in 7 Be soil content could be explained by the asymmetric rainfall regime. A highly linear relationship between rainfall amount and 7 Be deposition was observed in rain water. A good agreement between 7 Be soil content and 7 Be atmospheric deposition was noticed, mainly in wet months. 7 Be penetration in soil reaches a 5 cm depth, this could be explained by the soil type in the region. The soils are Acrisol type, characterized by low pH values and clay illuviation in deeper layers of the soil. In some regions of Brazil special attention should be paid if this radionuclide will be used as soil erosion tracer, taking into account the soil origin and its particular properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Wet and Occult Ion Deposition To An Elevated Forest Ecosystem In Switzerland

    Science.gov (United States)

    Buetzberger, P.; Burkard, R.; Eugster, W.

    Due to much higher ion concentrations in fogwater compared to rainwater, critical deposition levels of nutrients such as sulfate, nitrate or ammonium can be achieved in areas with high fog frequency. From summer 2001 until spring 2002 a measuring campaign of the FINIMSAS project (Fog Interception and Nutrient Inputs to Montane- Subalpine Areas in Switzerland) is being conducted at Laegeren (690m asl) on the Swiss Plateau. Fog frequency was high during our campaign. Similar measurements were carried out in 1986/87 at the exact same location, providing a reference data set for comparison. Because the deposition flux was measured differently during 1986/87, direct compar- isons are only possible for ion concentrations. Preliminary results show a significant decrease of sulfate and ammonium median concentrations of more than 50 % over this 15 year period, whereas nitrate decrease is relatively small. This corresponds well with the large-scale evolution of the air pollutant emissions of SO2 (major decrease) and NOx (relatively small decrease). The strong reduction of ammonium is probably due to the reduced use of fertilizer in the area. Chloride shows the largest decrease which can be attributed to the improvement of filtering technique of waste incinerations. In order to achieve maximum comparability, similar event types (e.g. advection fog vs. radiation fog) with similar meteorological conditions were interpreted individually. Analysis of fog nutrient input with respect to wind direction, wind speed, and origin of air mass will help to understand the influence of local and large-scale emissions on fog water concentrations in Switzerland. Computations based on half-hourly mean wind direction revealed significantly lower fog water input but higher median concentra- tions of all measured components if the dominating wind sector was East. Event-based wind field analyses were also carried out and compared to computed trajectories. In order to assess the influence of fog

  2. Deposition of chemically reactive and repellent sites on biosensor chips for reduced non-specific binding.

    Science.gov (United States)

    Gandhiraman, R P; Gubala, V; Le, N C H; Nam, Le Cao Hoai; Volcke, C; Doyle, C; James, B; Daniels, S; Williams, D E

    2010-08-01

    The performances of new polymeric materials with excellent optical properties and good machinability have led the biomedical diagnostics industry to develop cheap disposable biosensor platforms appropriate for point of care applications. Zeonor, a type of cycloolefin polymer (COP), is one such polymer that presents an excellent platform for biosensor chips. These polymer substrates have to be modified to have suitable physico-chemical properties for immobilizing proteins. In this work, we have demonstrated the amine functionalization of COP substrates, by plasma enhanced chemical vapour deposition (PECVD), through codeposition of ethylene diamine and 3-aminopropyltriethoxysilane precursors, for building chemistries on the plastic chip. The elemental composition, adhesion, ageing and reactivity of the plasma polymerized film were examined. The Si-O functionality present in amino silane contributed for a good interfacial adhesion of the coating to COP substrates and also acted as a network building layer for plasma polymerization. Wet chemical modification was then carried out on the amine functionalized chips to create chemically reactive isothiocyanate sites and protein repellent fluorinated sites on the same chip. The density of the reactive and repellent sites was altered by choosing appropriate mixtures of homofunctional phenyldiisothiocyanate (PDITC), pentafluoroisothiocyanate (5FITC) and phenylisothiocyanate (PITC) compounds. By tailoring the density of reactive binding sites and protein repellent sites, the non-specific binding of ssDNA has been decreased to a significant extent. Copyright 2010 Elsevier B.V. All rights reserved.

  3. Deposition of thermal and hot-wire chemical vapor deposition copper thin films on patterned substrates.

    Science.gov (United States)

    Papadimitropoulos, G; Davazoglou, D

    2011-09-01

    In this work we study the hot-wire chemical vapor deposition (HWCVD) of copper films on blanket and patterned substrates at high filament temperatures. A vertical chemical vapor deposition reactor was used in which the chemical reactions were assisted by a tungsten filament heated at 650 degrees C. Hexafluoroacetylacetonate Cu(I) trimethylvinylsilane (CupraSelect) vapors were used, directly injected into the reactor with the aid of a liquid injection system using N2 as carrier gas. Copper thin films grown also by thermal and hot-wire CVD. The substrates used were oxidized silicon wafers on which trenches with dimensions of the order of 500 nm were formed and subsequently covered with LPCVD W. HWCVD copper thin films grown at filament temperature of 650 degrees C showed higher growth rates compared to the thermally ones. They also exhibited higher resistivities than thermal and HWCVD films grown at lower filament temperatures. Thermally grown Cu films have very uniform deposition leading to full coverage of the patterned substrates while the HWCVD films exhibited a tendency to vertical growth, thereby creating gaps and incomplete step coverage.

  4. Continuous wet-only and dry-only deposition measurements of 137Cs and 7Be: an indicator of their origin

    International Nuclear Information System (INIS)

    Rosner, G.; Hoetzl, H.; Winkler, R.

    1996-01-01

    Series of monthly values of 137 Cs and 7 Be wet and dry deposition were measured with a wet-only and a dry-only collector each having an area of 2.25 m 2 . The results are presented for the period from November 1991 to May 1995. The behaviour of resuspended, Chernobyl-derived radiocesium is shown to be significantly different from that of cosmogenic 7 Be and from that of global fallout 137 Cs from nuclear weapons testing. The dry-to-total ratio of 0.65, the dry deposition velocity of 1.5 cm s -1 , the close correlation to the total amount of solids collected and the absence of a correlation between activity deposition and amount of rainfall point to a strong similarity in the deposition behaviour of present radiocesium and that of stable elements of terrestrial origin. (author)

  5. Continuous wet-only and dry-only deposition measurements of {sup 137}Cs and {sup 7}Be: an indicator of their origin

    Energy Technology Data Exchange (ETDEWEB)

    Rosner, G.; Hoetzl, H.; Winkler, R. [GSF - Forschungszentrum fuer Umwelt und Gesundheit Neuherberg GmbH, Oberschleissheim (Germany). Inst. fuer Strahlenschutz

    1996-09-01

    Series of monthly values of {sup 137}Cs and {sup 7}Be wet and dry deposition were measured with a wet-only and a dry-only collector each having an area of 2.25 m{sup 2}. The results are presented for the period from November 1991 to May 1995. The behaviour of resuspended, Chernobyl-derived radiocesium is shown to be significantly different from that of cosmogenic {sup 7}Be and from that of global fallout {sup 137}Cs from nuclear weapons testing. The dry-to-total ratio of 0.65, the dry deposition velocity of 1.5 cm s{sup -1}, the close correlation to the total amount of solids collected and the absence of a correlation between activity deposition and amount of rainfall point to a strong similarity in the deposition behaviour of present radiocesium and that of stable elements of terrestrial origin. (author).

  6. Cadmium sulfide thin films growth by chemical bath deposition

    Science.gov (United States)

    Hariech, S.; Aida, M. S.; Bougdira, J.; Belmahi, M.; Medjahdi, G.; Genève, D.; Attaf, N.; Rinnert, H.

    2018-03-01

    Cadmium sulfide (CdS) thin films have been prepared by a simple technique such as chemical bath deposition (CBD). A set of samples CdS were deposited on glass substrates by varying the bath temperature from 55 to 75 °C at fixed deposition time (25 min) in order to investigate the effect of deposition temperature on CdS films physical properties. The determination of growth activation energy suggests that at low temperature CdS film growth is governed by the release of Cd2+ ions in the solution. The structural characterization indicated that the CdS films structure is cubic or hexagonal with preferential orientation along the direction (111) or (002), respectively. The optical characterization indicated that the films have a fairly high transparency, which varies between 55% and 80% in the visible range of the optical spectrum, the refractive index varies from 1.85 to 2.5 and the optical gap value of which can reach 2.2 eV. It can be suggested that these properties make these films perfectly suitable for their use as window film in thin films based solar cells.

  7. Zinc oxide nanostructures by chemical vapour deposition as anodes for Li-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Laurenti, M., E-mail: marco.laurenti@iit.it [Center for Space Human Robotics @Polito, Istituto Italiano di Tecnologia, Corso Trento, 21, 10129 Turin (Italy); Department of Applied Science and Technology – DISAT, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin (Italy); Garino, N. [Center for Space Human Robotics @Polito, Istituto Italiano di Tecnologia, Corso Trento, 21, 10129 Turin (Italy); Porro, S.; Fontana, M. [Center for Space Human Robotics @Polito, Istituto Italiano di Tecnologia, Corso Trento, 21, 10129 Turin (Italy); Department of Applied Science and Technology – DISAT, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin (Italy); Gerbaldi, C., E-mail: claudio.gerbaldi@polito.it [Center for Space Human Robotics @Polito, Istituto Italiano di Tecnologia, Corso Trento, 21, 10129 Turin (Italy); Department of Applied Science and Technology – DISAT, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin (Italy)

    2015-08-15

    Highlights: • ZnO nanostructures are grown by simple chemical vapour deposition. • Polycrystalline nanostructured porous thin film is obtained. • Film exhibits stable specific capacity (∼400 mA h g{sup −1}) after prolonged cycling. • CVD-grown ZnO nanostructures show promising prospects as Li-ion battery anode. - Abstract: ZnO nanostructures are grown by a simple chemical vapour deposition method directly on a stainless steel disc current collector and successfully tested in lithium cells. The structural/morphological characterization points out the presence of well-defined polycrystalline nanostructures having different shapes and a preferential orientation along the c-axis direction. In addition, the high active surface of the ZnO nanostructures, which accounts for a large electrode/electrolyte contact area, and the complete wetting with the electrolyte solution are considered to be responsible for the good electrical transport properties and the adequate electrochemical behaviour, as confirmed by cyclic voltammetry and galvanostatic charge/discharge cycling. Indeed, despite no binder or conducting additives are used, when galvanostatically tested in lithium cells, after an initial decay, the ZnO nanostructures can provide a rather stable specific capacity approaching 70 μA h cm{sup −2} (i.e., around 400 mA h g{sup −1}) after prolonged cycling at 1 C, with very high Coulombic efficiency and an overall capacity retention exceeding 62%.

  8. Structural and chemical transformations in SnS thin films used in chemically deposited photovoltaic cells

    International Nuclear Information System (INIS)

    Avellaneda, David; Delgado, Guadalupe; Nair, M.T.S.; Nair, P.K.

    2007-01-01

    Chemically deposited SnS thin films possess p-type electrical conductivity. We report a photovoltaic structure: SnO 2 :F-CdS-SnS-(CuS)-silver print, with V oc > 300 mV and J sc up to 5 mA/cm 2 under 850 W/m 2 tungsten halogen illumination. Here, SnO 2 :F is a commercial spray-CVD (Pilkington TEC-8) coating, and the rest deposited from different chemical baths: CdS (80 nm) at 333 K, SnS (450 nm) and CuS (80 nm) at 293-303 K. The structure may be heated in nitrogen at 573 K, before applying the silver print. The photovoltaic behavior of the structure varies with heating: V oc ∼ 400 mV and J sc 2 , when heated at 423 K in air, but V oc decreases and J sc increases when heated at higher temperatures. These photovoltaic structures have been found to be stable over a period extending over one year by now. The overall cost of materials, simplicity of the deposition process, and possibility of easily varying the parameters to improve the cell characteristics inspire further work. Here we report two different baths for the deposition of SnS thin films of about 500 nm by chemical deposition. There is a considerable difference in the nature of growth, crystalline structure and chemical stability of these films under air-heating at 623-823 K or while heating SnS-CuS layers, evidenced in XRF and grazing incidence angle XRD studies. Heating of SnS-CuS films results in the formation of SnS-Cu x SnS y . 'All-chemically deposited photovoltaic structures' involving these materials are presented

  9. Chemical vapor deposition of refractory metals and ceramics III

    International Nuclear Information System (INIS)

    Gallois, B.M.; Lee, W.Y.; Pickering, M.A.

    1995-01-01

    The papers contained in this volume were originally presented at Symposium K on Chemical Vapor Deposition of Refractory Metals and Ceramics III, held at the Fall Meeting of the Materials Research Society in Boston, Massachusetts, on November 28--30, 1994. This symposium was sponsored by Morton International Inc., Advanced Materials, and by The Department of Energy-Oak Ridge National Laboratory. The purpose of this symposium was to exchange scientific information on the chemical vapor deposition (CVD) of metallic and ceramic materials. CVD technology is receiving much interest in the scientific community, in particular, to synthesize new materials with tailored chemical composition and physical properties that offer multiple functionality. Multiphase or multilayered films, functionally graded materials (FGMs), ''smart'' material structures and nanocomposites are some examples of new classes of materials being produced via CVD. As rapid progress is being made in many interdisciplinary research areas, this symposium is intended to provide a forum for reporting new scientific results and addressing technological issues relevant to CVD materials and processes. Thirty four papers have been processed separately for inclusion on the data base

  10. Synthesis of mullite coatings by chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Mulpuri, R.P.; Auger, M.; Sarin, V.K. [Boston Univ., MA (United States)

    1996-08-01

    Formation of mullite on ceramic substrates via chemical vapor deposition was investigated. Mullite is a solid solution of Al{sub 2}O{sub 3} and SiO{sub 2} with a composition of 3Al{sub 2}O{sub 3}{circ}2SiO{sub 2}. Thermodynamic calculations performed on the AlCl{sub 3}-SiCl{sub 4}-CO{sub 2}-H{sub 2} system were used to construct equilibrium CVD phase diagrams. With the aid of these diagrams and consideration of kinetic rate limiting factors, initial process parameters were determined. Through process optimization, crystalline CVD mullite coatings have been successfully grown on SiC and Si{sub 3}N{sub 4} substrates. Results from the thermodynamic analysis, process optimization, and effect of various process parameters on deposition rate and coating morphology are discussed.

  11. Bath parameter dependence of chemically deposited Copper Selenide thin film

    International Nuclear Information System (INIS)

    Al-Mamun; Islam, A.B.M.O.

    2004-09-01

    In this article, a low cost chemical bath deposition (CBD) technique has been used for the preparation Of Cu 2-x Se thin films on to glass substrate. Different thin fms (0.2-0.6/μm) were prepared by adjusting the bath parameter like concentration of ammonia, deposition time, temperature of the solution, and the ratios of the mixing composition between copper and selenium in the reaction bath. From these studies, it reveals that at low concentration of ammonia or TEA, the terminal thicknesses of the films are less, which gradually increases with the increase of concentrations and then drop down at still higher concentrations. It has been found that completing the Cu 2+ ions with EA first, and then addition of ammonia yields better results than the reverse process. The film thickness increases with the decrease of value x of Cu 2-x Se. (author)

  12. Kinetics of chemical vapor deposition of boron on molybdenum

    International Nuclear Information System (INIS)

    Tanaka, H.; Nakanishi, N.; Kato, E.

    1987-01-01

    Experimental rate data of chemical vapor deposition of boron by reduction of boron trichloride with hydrogen are analyzed to determine the reaction mechanism. The experiments were conducted at atmospheric pressure. The weight change of the sample was noted by means of a thermobalance. Molybdenum was used as the substrate. It has been found that the outer layer of the deposited film is Mo/sub 2/B/sub 5/ and the inner layer is MoB, and in the stational state of the reaction, the diffusion in the solid state is considered not to be rate controlling. When mass transport limitation was absent, the reaction orders with respect to boron trichloride and hydrogen were one third and one half, respectively. By comparing these orders with those obtained from Langmuir-Hinshelwood type equations, the rate controlling mechanism is identified to be the desorption of hydrogen chloride from the substrate

  13. Optimization of chemical displacement deposition of copper on porous silicon.

    Science.gov (United States)

    Bandarenka, Hanna; Redko, Sergey; Nenzi, Paolo; Balucani, Marco; Bondarenko, Vitaly

    2012-11-01

    Copper (II) sulfate was used as a source of copper to achieve uniform distribution of Cu particles deposited on porous silicon. Layers of the porous silicon were formed by electrochemical anodization of Si wafers in a mixture of HF, C3H7OH and deionized water. The well-known chemical displacement technique was modified to grow the copper particles of specific sizes. SEM and XRD analysis revealed that the outer surface of the porous silicon was covered with copper particles of the crystal orientation inherited from the planes of porous silicon skeleton. The copper crystals were found to have the cubic face centering elementary cell. In addition, the traces of Cu2O cubic primitive crystalline phases were identified. The dimensions of Cu particles were determined by the Feret's analysis of the SEM images. The sizes of the particles varied widely from a few to hundreds of nanometers. A phenomenological model of copper deposition was proposed.

  14. New luminescence lines in nanodiamonds obtained by chemical vapor deposition

    Science.gov (United States)

    Golubev, V. G.; Grudinkin, S. A.; Davydov, V. Yu.; Smirnov, A. N.; Feoktistov, N. A.

    2017-12-01

    The spectral characteristics of the photoluminescence lines detected for nanodiamonds obtained by the reactive ion etching of diamond particles in oxygen plasma, deposited by chemical vapor deposition on a silicon substrate, are studied. At room temperature, narrow lines are observed in the visible and infrared spectral regions, with a full width at half-maximum in the range of 1-2 nm at an almost complete absence of a broadband photoluminescence background signal. At decreasing temperature, the lines narrowed to 0.2-0.6 nm at T = 79 K, and the minimum line width was 0.055 nm at T = 10 K. With increasing temperature, the narrow lines shifted to the long-wavelength region of the spectrum, and their intensity decreased.

  15. Mixing and transport during pharmaceutical twin-screw wet granulation: experimental analysis via chemical imaging.

    Science.gov (United States)

    Kumar, Ashish; Vercruysse, Jurgen; Toiviainen, Maunu; Panouillot, Pierre-Emmanuel; Juuti, Mikko; Vanhoorne, Valérie; Vervaet, Chris; Remon, Jean Paul; Gernaey, Krist V; De Beer, Thomas; Nopens, Ingmar

    2014-07-01

    Twin-screw granulation is a promising continuous alternative for traditional batch high shear wet granulation (HSWG). The extent of HSWG in a twin screw granulator (TSG) is greatly governed by the residence time of the granulation materials in the TSG and degree of mixing. In order to determine the residence time distribution (RTD) and mixing in TSG, mostly visual observation and particle tracking methods are used, which are either inaccurate and difficult for short RTD, or provide an RTD only for a finite number of preferential tracer paths. In this study, near infrared chemical imaging, which is more accurate and provides a complete RTD, was used. The impact of changes in material throughput (10-17 kg/h), screw speed (500-900 rpm), number of kneading discs (2-12) and stagger angle (30-90°) on the RTD and axial mixing of the material was characterised. The experimental RTD curves were used to calculate the mean residence time, mean centred variance and the Péclet number to determine the axial mixing and predominance of convective over dispersive transport. The results showed that screw speed is the most influential parameter in terms of RTD and axial mixing in the TSG and established a significant interaction between screw design parameters (number and stagger angle of kneading discs) and the process parameters (material throughput and number of kneading discs). The results of the study will allow the development and validation of a transport model capable of predicting the RTD and macro-mixing in the TSG. These can later be coupled with a population balance model in order to predict granulation yields in a TSG more accurately. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Initiated chemical vapor deposition of pH responsive poly(2-diisopropylamino)ethyl methacrylate thin films

    Energy Technology Data Exchange (ETDEWEB)

    Karaman, Mustafa, E-mail: karamanm@selcuk.edu.tr [Department of Chemical Engineering, Selcuk University (Turkey); Advanced Technology Research and Application Center, Selcuk University (Turkey); Cabuk, Nihat [Department of Chemical Engineering, Selcuk University (Turkey)

    2012-08-31

    Poly(2-(diisopropylamino)ethyl methacrylate) (PDPAEMA) thin films were deposited on low temperature substrates by initiated chemical vapor deposition (iCVD) method using tertbutyl peroxide as an initiator. Very high deposition rates up to 38 nm/min were observed at low filament temperatures due to the use of the initiator. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy show the formation of PDPAEMA films with high retention of tertiary amine functionality which is responsible for pH induced changes in the wetting behavior of the surfaces. As-deposited PDPAEMA thin films on flat Si surface showed a reversible switching of water contact angle values between 87 Degree-Sign and 28 Degree-Sign ; after successive treatments of high and low pH water solutions, respectively. Conformal and non-damaging nature of iCVD allowed to functionalize fragile and rough electrospun poly(methyl methacrylate) fiber mat surfaces by PDPAEMA, which creates a surface with a switching behavior between superhydrophobic and approaching superhydrophilic with contact angle values of 155 {+-} 3 Degree-Sign and 22 {+-} 5 Degree-Sign , respectively. - Highlights: Black-Right-Pointing-Pointer Poly(2-diisopropylaminoethyl methacrylate) thin films were deposited by a dry process. Black-Right-Pointing-Pointer Initiated chemical vapor deposition can produce thin films on fragile substrates. Black-Right-Pointing-Pointer We report a reversible pH-induced transition from hydrophilic to super-hydrophobic.

  17. Ballistic transport in graphene grown by chemical vapor deposition

    International Nuclear Information System (INIS)

    Calado, V. E.; Goswami, S.; Xu, Q.; Vandersypen, L. M. K.; Zhu, Shou-En; Janssen, G. C. A. M.; Watanabe, K.; Taniguchi, T.

    2014-01-01

    In this letter, we report the observation of ballistic transport on micron length scales in graphene synthesised by chemical vapour deposition (CVD). Transport measurements were done on Hall bar geometries in a liquid He cryostat. Using non-local measurements, we show that electrons can be ballistically directed by a magnetic field (transverse magnetic focussing) over length scales of ∼1 μm. Comparison with atomic force microscope measurements suggests a correlation between the absence of wrinkles and the presence of ballistic transport in CVD graphene

  18. Handbook of chemical vapor deposition principles, technology and applications

    CERN Document Server

    Pierson, Hugh O

    1999-01-01

    Turn to this new second edition for an understanding of the latest advances in the chemical vapor deposition (CVD) process. CVD technology has recently grown at a rapid rate, and the number and scope of its applications and their impact on the market have increased considerably. The market is now estimated to be at least double that of a mere seven years ago when the first edition of this book was published. The second edition is an update with a considerably expanded and revised scope. Plasma CVD and metallo-organic CVD are two major factors in this rapid growth. Readers will find the latest

  19. Ballistic transport in graphene grown by chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Calado, V. E.; Goswami, S.; Xu, Q.; Vandersypen, L. M. K., E-mail: l.m.k.vandersypen@tudelft.nl [Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft (Netherlands); Zhu, Shou-En; Janssen, G. C. A. M. [Micro and Nano Engineering Laboratory, Precision and Microsystems Engineering, Delft University of Technology, 2628 CD Delft (Netherlands); Watanabe, K.; Taniguchi, T. [Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044 (Japan)

    2014-01-13

    In this letter, we report the observation of ballistic transport on micron length scales in graphene synthesised by chemical vapour deposition (CVD). Transport measurements were done on Hall bar geometries in a liquid He cryostat. Using non-local measurements, we show that electrons can be ballistically directed by a magnetic field (transverse magnetic focussing) over length scales of ∼1 μm. Comparison with atomic force microscope measurements suggests a correlation between the absence of wrinkles and the presence of ballistic transport in CVD graphene.

  20. Local emission of primary air pollutants and its contribution to wet deposition and concentrations of aerosols and gases in ambient air in Japan

    Science.gov (United States)

    Aikawa, Masahide; Hiraki, Takatoshi; Tomoyose, Nobutaka; Ohizumi, Tsuyoshi; Noguchi, Izumi; Murano, Kentaro; Mukai, Hitoshi

    2013-11-01

    We studied wet deposition by precipitation and the concentrations of aerosols and gases in ambient air in relation to the primary air pollutants discharged from domestic areas. The concentrations of aerosols and gases were influenced by nearby emissions except for non-sea-salt SO, which is transported long distances. The area facing the Sea of Japan showed much larger wet deposition than other areas, although the domestic emissions of the primary air pollutants there were small and showed a peak in wet deposition from October to March, as distinct from April to September in other areas. We performed the correlation analyses between wet deposition of each component and the product of the concentrations of corresponding aerosols and gases in ambient air and the two-thirds power of the precipitation. From the results, following scavenging processes were suggested. • Sulfate and ammonium were scavenged in precipitation as particulate matter such as (NH4)2SO4 and NH4HSO4. • Nitrate was scavenged mainly in precipitation through gaseous HNO3. • Ammonium was complementarily scavenged in precipitation through aerosols such as (NH4)2SO4 and NH4HSO4 and through gaseous NH3.

  1. Effect of wet depositions on losses of nutrients from soil on deforested areas in the Moravian-Silesian Beskids Mts. (the Czech Republic)

    Czech Academy of Sciences Publication Activity Database

    Fiala, Karel; Tůma, Ivan; Holub, P.

    2001-01-01

    Roč. 20, č. 4 (2001), s. 373-381 ISSN 1335-342X R&D Projects: GA ČR GA526/97/0170 Institutional research plan: CEZ:AV0Z6005908 Keywords : wet depositions * deforested area * Moravian-Silesian Beskids Mts. Subject RIV: EF - Botanics Impact factor: 0.192, year: 2001

  2. Chemical characteristics of atmospheric deposition collected at two ENEA stations near Bologna

    International Nuclear Information System (INIS)

    Barilli, L.; Olivieri, P.; Salvi, S.; Morselli, L.; Grandi, E.; Ianuccilli, A.

    1997-06-01

    This article presents the results of the measurements of the water quality in acid rains, collected by a Wet and Dry Sampler in 1994 and in 1995 at two ENEA stations, Brasimone and Bologna town, belonging to the RIDEP network and characterized by different geography and different anthropogenic sources. In the Bologna station from April 95 an innovative sampler DAS (Dry Deposition on Aquatic Surface) has been activated. The monitoring has allowed determining the wet deposition fluxes in both the stations and pointing out the differences between two areas characterized by different topology. Besides the DAS sampler has allowed evaluating the total deposition fluxes (wet and dry deposition) in the Bologna station and comparing them with the ''critical loads'' pertaining to the examined territory

  3. A comparative study of transfer factors of water, iodine and strontium on rye-grass and clover. Development of a model of evaluation of the limits of foliar contamination by wet deposit

    International Nuclear Information System (INIS)

    Angeletti, Livio; Levi, Emilio.

    1977-07-01

    Transfer factors of water, iodine ( 131 I) and strontium ( 85 Sr) on above-ground parts of rye-grass and clover were determined as a function of aspersion intensities. An analysis of the results showed the effect of aspersion intensities, nature of the chemical element and plant species on the values of transfer factors of iodine and strontium. It also made it possible to propose a simple method of evaluation of contamination limits of the aerial parts of plants by wet deposit, based on transfer values of water on plants only [fr

  4. Chemical characteristics, deposition fluxes and source apportionment of precipitation components in the Jiaozhou Bay, North China

    Science.gov (United States)

    Xing, Jianwei; Song, Jinming; Yuan, Huamao; Li, Xuegang; Li, Ning; Duan, Liqin; Qu, Baoxiao; Wang, Qidong; Kang, Xuming

    2017-07-01

    To systematically illustrate the chemical characteristics, deposition fluxes and potential sources of the major components in precipitation, 49 rainwater and snow water samples were collected in the Jiaozhou Bay from June 2015 to May 2016. We determined the pH, electric conductivity (EC) and the concentrations of main ions (Na+, K+, Ca2 +, Mg2 +, NH4+, SO42 -, NO3-, Cl- and F-) as well as analyzed their source contributions and atmospheric transport. The results showed that the precipitation samples were severely acidified with an annual volume-weighted mean (VWM) pH of 4.77. The frequency of acid precipitation (pH pollution level over the Jiaozhou Bay. Surprisingly, NH4+ (40.4%), which is higher than Ca2 + (29.3%), is the dominant species of cations, which is different from that in most areas of China. SO42 - was the most abundant anions, and accounted for 41.6% of the total anions. The wet deposition fluxes of sulfur (S) was 12.98 kg ha- 1 yr- 1. Rainfall, emission intensity and long-range transport of natural and anthropogenic pollutants together control the concentrations and wet deposition fluxes of chemical components in the precipitation. Non-sea-salt SO42 - and NO3- were the primary acid components while NH4+ and non-sea-salt Ca2 + were the dominating neutralizing constituents. The comparatively lower rainwater concentration of Ca2 + in the Jiaozhou Bay than that in other regions in Northern China likely to be a cause for the strong acidity of precipitation. Based on the combined enrichment factor and correlation analysis, the integrated contributions of sea-salt, crustal and anthropogenic sources to the total ions of precipitation were estimated to be 28.7%, 14.5% and 56.8%, respectively. However, the marine source fraction of SO42 - may be underestimated as the contribution from marine phytoplankton was neglected. Therefore, the precipitation components in the Jiaozhou Bay present complex chemical characteristics under the combined effects of natural

  5. Rain pH estimation based on the particulate matter pollutants and wet deposition study.

    Science.gov (United States)

    Singh, Shweta; Elumalai, Suresh Pandian; Pal, Asim Kumar

    2016-09-01

    In forecasting of rain pH, the changes caused by particulate matter (PM) are generally neglected. In regions of high PM concentration like Dhanbad, the role of PM in deciding the rain pH becomes important. Present work takes into account theoretical prediction of rain pH by two methods. First method considers only acid causing gases (ACG) like CO2, SO2 and NOx in pH estimation, whereas, second method additionally accounts for effect of PM (ACG-PM). In order to predict the rain pH, site specific deposited dust that represents local PM was studied experimentally for its impact on pH of neutral water. After incorporation of PM correction factor, it was found that, rain pH values estimated were more representative of the observed ones. Fractional bias (FB) for the ACG-PM method reduced to values of the order of 10(-2) from those with order of 10(-1) for the ACG method. The study confirms neutralization of rain acidity by PM. On account of this, rain pH was found in the slightly acidic to near neutral range, despite of the high sulfate flux found in rain water. Although, the safer range of rain pH blurs the severity of acid rain from the picture, yet huge flux of acidic and other ions get transferred to water bodies, soil and ultimately to the ground water system. Simple use of rain pH for rain water quality fails to address the issues of its increased ionic composition due to the interfering pollutants and thus undermines severity of pollutants transferred from air to rain water and then to water bodies and soil. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Nitrogen-doped graphene by microwave plasma chemical vapor deposition

    International Nuclear Information System (INIS)

    Kumar, A.; Voevodin, A.A.; Paul, R.; Altfeder, I.; Zemlyanov, D.; Zakharov, D.N.; Fisher, T.S.

    2013-01-01

    Rapid synthesis of nitrogen-doped, few-layer graphene films on Cu foil is achieved by microwave plasma chemical vapor deposition. The films are doped during synthesis by introduction of nitrogen gas in the reactor. Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy and scanning tunneling microscopy reveal crystal structure and chemical characteristics. Nitrogen concentrations up to 2 at.% are observed, and the limit is linked to the rigidity of graphene films on copper surfaces that impedes further nitrogen substitutions of carbon atoms. The entire growth process requires only a few minutes without supplemental substrate heating and offers a promising path toward large-scale synthesis of nitrogen-doped graphene films. - Highlights: ► Rapid synthesis of nitrogen doped few layer graphene on Cu foil. ► Defect density increment on 2% nitrogen doping. ► Nitrogen doped graphene is a good protection to the copper metallic surface

  7. Nitrogen-doped graphene by microwave plasma chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, A., E-mail: kumar50@purdue.edu [Birck Nanotechnolgy Center, Purdue University, West Lafayette, IN 47907 (United States); Voevodin, A.A. [Birck Nanotechnolgy Center, Purdue University, West Lafayette, IN 47907 (United States); Materials and Manufacturing Directorate, Air Force Research Laboratory, WPAFB, OH 45433 (United States); Paul, R. [Birck Nanotechnolgy Center, Purdue University, West Lafayette, IN 47907 (United States); Altfeder, I. [Materials and Manufacturing Directorate, Air Force Research Laboratory, WPAFB, OH 45433 (United States); Zemlyanov, D.; Zakharov, D.N. [Birck Nanotechnolgy Center, Purdue University, West Lafayette, IN 47907 (United States); Fisher, T.S., E-mail: tsfisher@purdue.edu [Birck Nanotechnolgy Center, Purdue University, West Lafayette, IN 47907 (United States); Materials and Manufacturing Directorate, Air Force Research Laboratory, WPAFB, OH 45433 (United States)

    2013-01-01

    Rapid synthesis of nitrogen-doped, few-layer graphene films on Cu foil is achieved by microwave plasma chemical vapor deposition. The films are doped during synthesis by introduction of nitrogen gas in the reactor. Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy and scanning tunneling microscopy reveal crystal structure and chemical characteristics. Nitrogen concentrations up to 2 at.% are observed, and the limit is linked to the rigidity of graphene films on copper surfaces that impedes further nitrogen substitutions of carbon atoms. The entire growth process requires only a few minutes without supplemental substrate heating and offers a promising path toward large-scale synthesis of nitrogen-doped graphene films. - Highlights: ► Rapid synthesis of nitrogen doped few layer graphene on Cu foil. ► Defect density increment on 2% nitrogen doping. ► Nitrogen doped graphene is a good protection to the copper metallic surface.

  8. ZnS nanoflakes deposition by modified chemical method

    International Nuclear Information System (INIS)

    Desai, Mangesh A.; Sartale, S. D.

    2014-01-01

    We report deposition of zinc sulfide nanoflakes on glass substrates by modified chemical method. The modified chemical method involves adsorption of zinc–thiourea complex on the substrate and its dissociation in presence of hydroxide ions to release sulfur ions from thiourea which react with zinc ions present in the complex to form zinc sulfide nanoflakes at room temperature. Influence of zinc salt and thiourea concentrations ratios on the morphology of the films was investigated by scanning electron microscope (SEM). The ratio of zinc and thiourea in the zinc–thiourea complex significantly affect the size of the zinc sulfide nanoflakes, especially width and density of the nanoflakes. The X-ray diffraction analysis exhibits polycrystalline nature of the zinc sulfide nanoflakes with hexagonal phase

  9. Ti-doped hydrogenated diamond like carbon coating deposited by hybrid physical vapor deposition and plasma enhanced chemical vapor deposition

    Science.gov (United States)

    Lee, Na Rae; Sle Jun, Yee; Moon, Kyoung Il; Sunyong Lee, Caroline

    2017-03-01

    Diamond-like carbon films containing titanium and hydrogen (Ti-doped DLC:H) were synthesized using a hybrid technique based on physical vapor deposition (PVD) and plasma enhanced chemical vapor deposition (PECVD). The film was deposited under a mixture of argon (Ar) and acetylene gas (C2H2). The amount of Ti in the Ti-doped DLC:H film was controlled by varying the DC power of the Ti sputtering target ranging from 0 to 240 W. The composition, microstructure, mechanical and chemical properties of Ti-doped DLC:H films with varying Ti concentrations, were investigated using Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), nano indentation, a ball-on-disk tribometer, a four-point probe system and dynamic anodic testing. As a result, the optimum composition of Ti in Ti-doped DLC:H film using our hybrid method was found to be a Ti content of 18 at. %, having superior electrical conductivity and high corrosion resistance, suitable for bipolar plates. Its hardness value was measured to be 25.6 GPa with a low friction factor.

  10. Spatial patterns and temporal trends in mercury concentrations, precipitation depths, and mercury wet deposition in the North American Great Lakes region, 2002–2008

    International Nuclear Information System (INIS)

    Risch, Martin R.; Gay, David A.; Fowler, Kathleen K.; Keeler, Gerard J.; Backus, Sean M.; Blanchard, Pierrette; Barres, James A.; Dvonch, J. Timothy

    2012-01-01

    Annual and weekly mercury (Hg) concentrations, precipitation depths, and Hg wet deposition in the Great Lakes region were analyzed by using data from 5 monitoring networks in the USA and Canada for a 2002–2008 study period. High-resolution maps of calculated annual data, 7-year mean data, and net interannual change for the study period were prepared to assess spatial patterns. Areas with 7-year mean annual Hg concentrations higher than the 12 ng per liter water-quality criterion were mapped in 4 states. Temporal trends in measured weekly data were determined statistically. Monitoring sites with significant 7-year trends in weekly Hg wet deposition were spatially separated and were not sites with trends in weekly Hg concentration. During 2002–2008, Hg wet deposition was found to be unchanged in the Great Lakes region and its subregions. Any small decreases in Hg concentration apparently were offset by increases in precipitation. - Highlights: ► Data from 5 Hg and precipitation networks in the USA and Canada were combined for the first time. ► High-resolution maps and statistical trends tests were used for spatial and temporal data analysis. ► Some 7-year mean annual Hg concentrations exceeded a 12 ng per liter water-quality criterion. ► Small, localized decreases in Hg concentration were offset by increases in precipitation. ► Hg wet deposition was unchanged in the Great Lakes region and its subregions during 2002–2008. - Analysis of monitoring data from 5 networks in the USA and Canada determined that mercury wet deposition was unchanged in the North American Great Lakes region during 2002–2008.

  11. Comparative study of tantalum deposition by chemical vapor deposition and electron beam vacuum evaporation

    International Nuclear Information System (INIS)

    Spitz, J.; Chevallier, J.

    1975-01-01

    The coating by tantalum of steel parts has been carried out by the two following methods: chemical vapor deposition by hydrogen reduction of TaCl 5 (temperature=1100 deg C, pressure=200 mmHg, H 2 /TaCl 5 =10); electron beam vacuum evaporation. In this case Ta was firstly condensed by ion plating (P(Ar)=5x10 -3 up to 2x10 -2 mmHg; U(c)=3 to -4kV and J(c)=0.2 to 1mAcm -2 ) in order to ensure a good adhesion between deposit and substrate; then by vacuum condensation (substrate temperature: 300 to 650 deg C) to ensure that the coating is impervious to HCl an H 2 SO 4 acids. The advantages and inconveniences of each method are discussed [fr

  12. Parallel measurements of organic and elemental carbon dry (PM1, PM2.5) and wet (rain, snow, mixed) deposition into the Baltic Sea.

    Science.gov (United States)

    Witkowska, Agnieszka; Lewandowska, Anita; Falkowska, Lucyna M

    2016-03-15

    Parallel studies on organic and elemental carbon in PM1 and PM2.5 aerosols and in wet deposition in various forms of its occurrence were conducted in the urbanised coastal zone of the Baltic Sea. The carbon load introduced into the sea water was mainly affected by the form of precipitation. Dry deposition load of carbon was on average a few orders of magnitude smaller than wet deposition. The suspended organic carbon was more effectively removed from the air with rain than snow, while an inverse relationship was found for elemental carbon. However the highest flux of water insoluble organic carbon was recorded in precipitation of a mixed nature. The atmospheric cleaning of highly dissolved organic carbon was observed to be the most effective on the first day of precipitation, while the hydrophobic elemental carbon was removed more efficiently when the precipitation lasted longer than a day. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Precipitation composition and wet deposition temporal pattern in Central Serbia for the period from 1998 to 2004.

    Science.gov (United States)

    Golobocanin, D; Zujić, A; Milenković, A; Miljević, N

    2008-07-01

    Bulk samples collected on a daily basis at three principal meteorological stations in central Serbia were analyzed on chloride (Cl(-)), nitrate (NO(3)(-)), sulfate (SO(4)(2-)), sodium (Na(+)), ammonium (NH(4)(+)), potassium (K(+)), calcium (Ca(2+)), and magnesium (Mg(2+)) in addition to precipitation amount, pH and conductivity measurements over the period 1998-2004. The data were subjected to variety of analyses (linear regression, principal component analysis, time series analysis) to characterize precipitation chemistry in the study area. The most abundant ion was SO(2-)(4) with annual volume weighted mean concentration of 242 microeq L(-1). Neutralization of precipitation acidity occurs both as a result of the dissolution of alkaline compounds containing Ca(2+), Mg(2+), and K(+) as well as the absorption of ammonia. The ratio of SO(4)(2-)/NO(3)(-) was above 5, which indicated that the combustion process of low-grade domestic lignite for electricity generation from coal-fired thermal power plants was the main source of pollution in the investigated area. A considerable mean annual bulk wet deposition of SO(4)-S determined by precipitation amount and concentrations of sulfate in the precipitation was calculated to be 12-35 kg ha(-1).

  14. NASA evaluation of Type 2 chemical depositions. [effects of deicer deposition on aircraft tire friction performance

    Science.gov (United States)

    Yager, Thomas J.; Stubbs, Sandy M.; Howell, W. Edward; Webb, Granville L.

    1993-01-01

    Recent findings from NASA Langley tests to define effects of aircraft Type 2 chemical deicer depositions on aircraft tire friction performance are summarized. The Aircraft Landing Dynamics Facility (ALDF) is described together with the scope of the tire cornering and braking friction tests conducted up to 160 knots ground speed. Some lower speed 32 - 96 km/hr (20 - 60 mph) test run data obtained using an Instrumented Tire Test Vehicle (ITTV) to determine effects of tire bearing pressure and transverse grooving on cornering friction performance are also discussed. Recommendations are made concerning which parameters should be evaluated in future testing.

  15. Deposition of controllable preferred orientation silicon films on glass by inductively coupled plasma chemical vapor deposition

    International Nuclear Information System (INIS)

    Li Junshuai; Wang Jinxiao; Yin Min; Gao Pingqi; He Deyan; Chen Qiang; Li Yali; Shirai, Hajime

    2008-01-01

    An inductively coupled plasma (ICP) system with the adjustable distance between the inductance coil and substrates was designed to effectively utilize the spatial confinement of ICP discharge, and then control the gas-phase transport process. The effects of the gas phase processes on the crystallinity and preferred orientation of silicon films deposited on glass were systematically investigated. The investigation was conducted in the ICP-chemical vapor deposition process with the precursor gas of a SiH 4 /H 2 mixture at a substrate temperature of 350 deg. Highly crystallized silicon films with different preferred orientations, (111) or (220), could be selectively deposited by adjusting the SiH 4 dilution ratio [R=[SiH 4 ]/([SiH 4 ]+[H 2 ])] or total working pressure. When the total working pressure is 20 Pa, the crystallinity of the silicon films increases with the increase of the SiH 4 dilution ratio, while the preferred orientation was changed from (111) to (220). In the case of the fixed SiH 4 dilution (10%), the silicon film with I (220) /I (111) of about 3.5 and Raman crystalline fraction of about 89.6% has been deposited at 29.7 nm/min when the total working pressure was increased to 40 Pa. At the fixed SiH 4 partial pressure of 2 Pa, the film crystallinity decreases and the preferred orientation is always (111) with increasing the H 2 partial pressure from 18 to 58 Pa. Atomic force microscope reveals that the film deposited at a relatively high H 2 partial pressure has a very rough surface caused by the devastating etching of H atoms to the silicon network

  16. Hysteresis losses in iron oxide nanoparticles prepared by glass crystallization or wet chemical precipitation

    International Nuclear Information System (INIS)

    Mueller, Robert; Dutz, Silvio; Hergt, Rudolf; Schmidt, Christopher; Steinmetz, Hanna; Zeisberger, Matthias; Gawalek, Wolfgang

    2007-01-01

    Ferrofluids were prepared from glass crystallized as well as wet precipitated iron oxide particles. Comparing hysteresis losses versus applied field amplitude from particles in immobilized state (powder) and in fluid state (ferrofluid) shows in some cases anomalous large losses at low magnetic fields. The influence of texture on the losses was investigated

  17. Polycrystalline thin films of antimony selenide via chemical bath deposition and post deposition treatments

    International Nuclear Information System (INIS)

    Rodriguez-Lazcano, Y.; Pena, Yolanda; Nair, M.T.S.; Nair, P.K.

    2005-01-01

    We report a method for obtaining thin films of polycrystalline antimony selenide via chemical bath deposition followed by heating the thin films at 573 K in selenium vapor. The thin films deposited from chemical baths containing one or more soluble complexes of antimony, and selenosulfate initially did not show X-ray diffraction (XRD) patterns corresponding to crystalline antimony selenide. Composition of the films, studied by energy dispersive X-ray analyses indicated selenium deficiency. Heating these films in presence of selenium vapor at 573 K under nitrogen (2000 mTorr) resulted in an enrichment of Se in the films. XRD peaks of such films matched Sb 2 Se 3 . Evaluation of band gap from optical spectra of such films shows absorption due to indirect transition occurring in the range of 1-1.2 eV. The films are photosensitive, with dark conductivity of about 2 x 10 -8 (Ω cm) -1 and photoconductivity, about 10 -6 (Ω cm) -1 under tungsten halogen lamp illumination with intensity of 700 W m -2 . An estimate for the mobility life time product for the film is 4 x 10 -9 cm 2 V -1

  18. Thermoluminescence characterisation of chemical vapour deposited diamond films

    CERN Document Server

    Mazzocchi, S; Bucciolini, M; Cuttone, G; Pini, S; Sabini, M G; Sciortino, S

    2002-01-01

    The thermoluminescence (TL) characteristics of a set of six chemical vapour deposited diamond films have been studied with regard to their use as off-line dosimeters in radiotherapy. The structural characterisation has been performed by means of Raman spectroscopy. Their TL responses have been tested with radiotherapy beams ( sup 6 sup 0 Co photons, photons and electrons from a linear accelerator (Linac), 26 MeV protons from a TANDEM accelerator) in the dose range 0.1-7 Gy. The dosimetric characterisation has yielded a very good reproducibility, a very low dependence of the TL response on the type of particle and independence of the radiation energy. The TL signal is not influenced by the dose rate and exhibits a very low thermal fading. Moreover, the sensitivity of the diamond samples compares favourably with that of standard TLD100 dosimeters.

  19. Chemical vapour deposition synthetic diamond: materials, technology and applications

    International Nuclear Information System (INIS)

    Balmer, R S; Brandon, J R; Clewes, S L; Dhillon, H K; Dodson, J M; Friel, I; Inglis, P N; Madgwick, T D; Markham, M L; Mollart, T P; Perkins, N; Scarsbrook, G A; Twitchen, D J; Whitehead, A J; Wilman, J J; Woollard, S M

    2009-01-01

    Substantial developments have been achieved in the synthesis of chemical vapour deposition (CVD) diamond in recent years, providing engineers and designers with access to a large range of new diamond materials. CVD diamond has a number of outstanding material properties that can enable exceptional performance in applications as diverse as medical diagnostics, water treatment, radiation detection, high power electronics, consumer audio, magnetometry and novel lasers. Often the material is synthesized in planar form; however, non-planar geometries are also possible and enable a number of key applications. This paper reviews the material properties and characteristics of single crystal and polycrystalline CVD diamond, and how these can be utilized, focusing particularly on optics, electronics and electrochemistry. It also summarizes how CVD diamond can be tailored for specific applications, on the basis of the ability to synthesize a consistent and engineered high performance product.

  20. Chemical vapor deposition of amorphous ruthenium-phosphorus alloy films

    International Nuclear Information System (INIS)

    Shin Jinhong; Waheed, Abdul; Winkenwerder, Wyatt A.; Kim, Hyun-Woo; Agapiou, Kyriacos; Jones, Richard A.; Hwang, Gyeong S.; Ekerdt, John G.

    2007-01-01

    Chemical vapor deposition growth of amorphous ruthenium-phosphorus films on SiO 2 containing ∼ 15% phosphorus is reported. cis-Ruthenium(II)dihydridotetrakis-(trimethylphosphine), cis-RuH 2 (PMe 3 ) 4 (Me = CH 3 ) was used at growth temperatures ranging from 525 to 575 K. Both Ru and P are zero-valent. The films are metastable, becoming increasingly more polycrystalline upon annealing to 775 and 975 K. Surface studies illustrate that demethylation is quite efficient near 560 K. Precursor adsorption at 135 K or 210 K and heating reveal the precursor undergoes a complex decomposition process in which the hydride and trimethylphosphine ligands are lost at temperatures as low at 280 K. Phosphorus and its manner of incorporation appear responsible for the amorphous-like character. Molecular dynamics simulations are presented to suggest the local structure in the films and the causes for phosphorus stabilizing the amorphous phase

  1. Chemical vapour deposition of freestanding sub-60 nm graphene gyroids

    Science.gov (United States)

    Cebo, Tomasz; Aria, Adrianus I.; Dolan, James A.; Weatherup, Robert S.; Nakanishi, Kenichi; Kidambi, Piran R.; Divitini, Giorgio; Ducati, Caterina; Steiner, Ullrich; Hofmann, Stephan

    2017-12-01

    The direct chemical vapour deposition of freestanding graphene gyroids with controlled sub-60 nm unit cell sizes is demonstrated. Three-dimensional (3D) nickel templates were fabricated through electrodeposition into a selectively voided triblock terpolymer. The high temperature instability of sub-micron unit cell structures was effectively addressed through the early introduction of the carbon precursor, which stabilizes the metallized gyroidal templates. The as-grown graphene gyroids are self-supporting and can be transferred onto a variety of substrates. Furthermore, they represent the smallest free standing periodic graphene 3D structures yet produced with a pore size of tens of nm, as analysed by electron microscopy and optical spectroscopy. We discuss generality of our methodology for the synthesis of other types of nanoscale, 3D graphene assemblies, and the transferability of this approach to other 2D materials.

  2. Polarized Raman spectroscopy of chemically vapour deposited diamond films

    International Nuclear Information System (INIS)

    Prawer, S.; Nugent, K.W.; Weiser, P.S.

    1994-01-01

    Polarized micro-Raman spectra of chemically vapour deposited diamond films are presented. It is shown that important parameters often extracted from the Raman spectra such as the ratio of the diamond to non-diamond component of the films and the estimation of the level of residual stress depend on the orientation of the diamond crystallites with respect to the polarization of the incident laser beam. The dependence originates from the fact that the Raman scattering from the non-diamond components in the films is almost completely depolarized whilst the scattering from the diamond components is strongly polarized. The results demonstrate the importance of taking polarization into account when attempting to use Raman spectroscopy in even a semi-quantitative fashion for the assessment of the purity, perfection and stress in CVD diamond films. 8 refs., 1 tab. 2 figs

  3. Chemical vapor deposition of TiB2 on graphite

    International Nuclear Information System (INIS)

    Pierson, H.O.; Randich, E.; Mattox, D.M.

    1978-01-01

    This study is an experimental investigation of the coating of graphite with TiB 2 by chemical vapor deposition (CVD) using the hydrogen reduction of BCl 3 and TiCl 4 at 925 0 C and 1 atm. Reasonable matching of the thermal expansion of TiB 2 and graphite was necessary to eliminate cracking. A suitable graphite was POCO DFP-1. Adhesion was improved by having a slightly rough graphite surface. Heat treatment at 2000 0 C and above resulted in a certain degree of diffusion. No melting or solid phases other than TiB 2 and graphite were detected up to 2400 0 C. The coatings showed no failure when repeatedly submitted to an electron beam pulse of 2 KW/cm 2 for 0.8 sec

  4. Anisotropic Friction of Wrinkled Graphene Grown by Chemical Vapor Deposition.

    Science.gov (United States)

    Long, Fei; Yasaei, Poya; Yao, Wentao; Salehi-Khojin, Amin; Shahbazian-Yassar, Reza

    2017-06-21

    Wrinkle structures are commonly seen on graphene grown by the chemical vapor deposition (CVD) method due to the different thermal expansion coefficient between graphene and its substrate. Despite the intensive investigations focusing on the electrical properties, the nanotribological properties of wrinkles and the influence of wrinkle structures on the wrinkle-free graphene remain less understood. Here, we report the observation of anisotropic nanoscale frictional characteristics depending on the orientation of wrinkles in CVD-grown graphene. Using friction force microscopy, we found that the coefficient of friction perpendicular to the wrinkle direction was ∼194% compare to that of the parallel direction. Our systematic investigation shows that the ripples and "puckering" mechanism, which dominates the friction of exfoliated graphene, plays even a more significant role in the friction of wrinkled graphene grown by CVD. The anisotropic friction of wrinkled graphene suggests a new way to tune the graphene friction property by nano/microstructure engineering such as introducing wrinkles.

  5. Plasma Enhanced Chemical Vapour Deposition of Horizontally Aligned Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Matthew T. Cole

    2013-05-01

    Full Text Available A plasma-enhanced chemical vapour deposition reactor has been developed to synthesis horizontally aligned carbon nanotubes. The width of the aligning sheath was modelled based on a collisionless, quasi-neutral, Child’s law ion sheath where these estimates were empirically validated by direct Langmuir probe measurements, thereby confirming the proposed reactors ability to extend the existing sheath fields by up to 7 mm. A 7 mbar growth atmosphere combined with a 25 W plasma permitted the concurrent growth and alignment of carbon nanotubes with electric fields of the order of 0.04 V μm−1 with linear packing densities of up to ~5 × 104 cm−1. These results open up the potential for multi-directional in situ alignment of carbon nanotubes providing one viable route to the fabrication of many novel optoelectronic devices.

  6. Thermoluminescence of Zn O thin films deposited by chemical bath

    International Nuclear Information System (INIS)

    Camacho A, M. C.; Cruz V, C.; Bernal H, R.; Berman M, D.; Castano M, V. M.

    2015-10-01

    Full text: Zn O films on Si were synthesized using a deposition method by chemical bath and thermally treated at 900 degrees C for 12 h in air. The morphological characterization by scanning electron microscopy reveals that uniform films were obtained. To investigate the thermoluminescent properties of the films were exposed to irradiation with beta particles with doses in the range from 0.5 to 128 Gy. The brightness curves obtained using a heating rate of 5 degrees C have two peaks, one at 124 and another at 270 degrees C, and a linear dependence of the integrated thermoluminescence as a function of dose. The second maximum reveals the existence of localized trapping states of potential utility in thermoluminescent dosimetry. (Author)

  7. Chemically vapor deposited coatings for multibarrier containment of nuclear wastes

    International Nuclear Information System (INIS)

    Rusin, J.M.; Shade, J.W.; Kidd, R.W.; Browning, M.F.

    1981-01-01

    Chemical vapor deposition (CVD) was selected as a feasible method to coat ceramic cores, since the technology has previously been demonstrated for high-temperature gas-cooled reactor (HTGR) fuel particles. CVD coatings, including SiC, PyC (pyrolytic carbon), SiO 2 , and Al 2 O 3 were studied. This paper will discuss the development and characterization of PyC and Al 2 O 3 CVD coatings on supercalcine cores. Coatings were applied to 2 mm particles in either fluidized or vibrating beds. The PyC coating was deposited in a fluidized bed with ZrO 2 diluent from C 2 H 2 at temperatures between 1100 and 1200 0 C. The Al 2 O 3 coatings were deposited in a vibrated bed by a two-stage process to minimize loss of PyC during the overcoating operation. This process involved applying 10 μm of Al 2 O 3 using water vapor hydrolysis of AlCl 3 and then switching to the more surface-controlled hydrolysis via the H 2 + CO 2 reaction (3CO 2 + 3H 2 + 2AlCl 3 = Al 2 O 3 + 6HCl + 3CO). Typically, 50 to 80 μm Al 2 O 3 coatings were applied over 30 to 40 μm PyC coatings. The coatings were evaluated by metallographic examination, PyC oxidation tests, and leach resistance. After air oxidation for 100 hours at 750 0 C, the duplex PyC/Al 2 O 3 coated particles exhibited a weight loss of 0.01 percent. Leach resistance is being determined for temperatures from 50 to 150 0 C in various solutions. Typical results are given for selected ions. The leach resistance of supercalcine cores is significantly improved by the application of PyC and/or Al 2 O 3 coatings

  8. Cobalt Xanthate Thin Film with Chemical Bath Deposition

    Directory of Open Access Journals (Sweden)

    İ. A. Kariper

    2013-01-01

    Full Text Available Cobalt xanthate thin films (CXTFs were successfully deposited by chemical bath deposition, onto amorphous glass substrates, as well as on p- and n-silicon, indium tin oxide, and poly(methyl methacrylate. The structure of the films was analyzed by far-infrared spectrum (FIR, mid-infrared (MIR spectrum, nuclear magnetic resonance (NMR, and scanning electron microscopy (SEM. These films were investigated from their structural, optical, and electrical properties point of view. Electrical properties were measured using four-point method, whereas optical properties were investigated via UV-VIS spectroscopic technique. Uniform distribution of grains was clearly observed from the photographs taken by scanning electron microscope (SEM. The transmittance was about 70–80% (4 hours, 50°C. The optical band gap of the CXTF was graphically estimated to be 3.99–4.02 eV. The resistivity of the films was calculated as 22.47–75.91 Ω·cm on commercial glass depending on film thickness and 44.90–73.10 Ω ·cm on the other substrates. It has been observed that the relative resistivity changed with film thickness. The MIR and FIR spectra of the films were in agreement with the literature analogues. The expected peaks of cobalt xanthate were observed in NMR analysis on glass. The films were dipped in chloroform as organic solvent and were analyzed by NMR.

  9. Chemical vapor deposition of yttria stabilized zirconia in porous substrates

    International Nuclear Information System (INIS)

    Carolan, M.F.; Michaels, J.N.

    1987-01-01

    Electrochemical vapor deposition (EVD) of yttria stabilized zirconia (YSZ) is the preferred route to the production of thin films of YSZ on porous substrates. This process has been used in the construction of both fuel cells and steam electrolyzers. A critical aspect of the EVD process is an initial chemical vapor deposition phase in which the pores of a porous substrate are plugged by YSZ. In this process, water vapor and a mixture of gaseous zirconium chloride and yttrium chloride diffuse into the porous substrate from opposite sides and react to form YSZ and HCl ga. During the second stage of the process a continuous dense film of electrolyte is formed by a tarnishing-type process. Experimentally it is observed that the pores plug within a few pore diameters of the metal chloride face of the substrate. A kinetic rate expression that is first order in metal chloride but zero order in water is best able to explain this phenomenon. With this rate expression, the pores always plug near the metal chloride face. The model predicts less pore narrowing to occur as the ratio of the reaction rate to the diffusion rate of the metal chloride is increased. A kinetic rate expression that is first order in both water and metal chloride predicts that the pores plug much deeper in the substrate

  10. Chemical vapour deposition of vanadium oxide thermochromic thin films

    Science.gov (United States)

    Piccirillo, Clara

    Thermochromic materials change optical properties, such as transmittance or reflectance, with a variation in temperature. An ideal intelligent (smart) material will allow solar radiation in through a window in cold conditions, but reflect that radiation in warmer conditions. The variation in the properties is often associated with a phase change, which takes place at a definite temperature, and is normally reversible. Such materials are usually applied to window glass as thin films. This thesis presents the work on the development of thermochromic vanadium (IV) oxide (VO2) thin films - both undoped and doped with tungsten, niobium and gold nanoparticles - which could be employed as solar control coatings. The films were deposited using Chemical Vapour Deposition (CVD), using improved Atmospheric Pressure (APCVD), novel Aerosol Assisted (AACVD) and novel hybrid AP/AACVD techniques. The effects of dopants on the metalto- semiconductor transition temperature and transmittance/reflectance characteristics were also investigated. This work significantly increased the understanding of the mechanisms behind thermochromic behaviour, and resulted in thermochromic materials based on VO2 with greatly improved properties.

  11. Wet Deposition of Trace Metals at a Typical Urban Site in Southwestern China: Fluxes, Sources and Contributions to Aquatic Environments

    Directory of Open Access Journals (Sweden)

    Liuyi Zhang

    2017-12-01

    Full Text Available In this study, we quantified the atmospheric wet deposition (AWD of 13 trace metals (TMs and estimated their potential effects on the surface water of the Three Gorges Reservoir in China. Precipitation was collected in Wanzhou in southwestern China from March 2015 to February 2016. The concentrations and fluxes of the 13 TMs were in the ranges of 0.16–9.44 µg L−1 and 0.18–10.22 mg m−2 yr−1, respectively, in the order Al > Zn > Fe > Ba > Pb > Mn > Ti > Cd > Cu > As > V > Ni ≈ Cr. Using principal component analysis, it was found that Al, Ba, Cu, Fe, Mn and Zn were mainly derived from a mixture of soil and road dust, As, Cd, Cr, Pb and Ti primarily originated from the local industries, and Ni and V were related to diesel and gasoline combustion, including both vehicle exhaust emissions and ship emissions from the nearby Yangtze River. The estimated TM inputs to the Three Gorges Reservoir were 11.1, 11.0, 5.7, 5.3, 4.5, 2.7, 2.5, 1.5, 1.0, 0.7, 0.5, 0.2, and 0.2 t yr−1 for Al, Zn, Fe, Ba, Pb, Mn, Ti, Cd, Cu, As, V, Ni and Cr, respectively. The AWD TM fluxes in Wanzhou were lower than those in metropolises and their inputs were limited for surface water of the Three Gorges Reservoir. However, Cd was strongly enriched in precipitation and rainstorms greatly increased the surface water concentrations of Cd and Pb. Therefore, the behavior of Cd and Pb in southwestern mountain areas of China, including emission, transport, transformation, and their ecological effects, should be given more attention in future studies.

  12. Morphology, conductivity, and wetting characteristics of PEDOT:PSS thin films deposited by spin and spray coating

    Energy Technology Data Exchange (ETDEWEB)

    Zabihi, F.; Xie, Y.; Gao, S.; Eslamian, M., E-mail: Morteza.Eslamian@sjtu.edu.cn

    2015-05-30

    Highlights: • Nanostructure of spun-on and spray-on PEDOT:PSS thin films is studied. • A correlation is established between the film nanostructure and electrical conductivity. • Effect of process parameters is studied on the film characteristics. • A high solution concentration, high process temperature and multiple deposition layers are recommended. - Abstract: The goal of this paper is to study the characteristics of PEDOT:PSS thin films and the effects of varying the processing parameters on the structure, functionality, and surface wetting of spun-on and spray-on PEDOT:PSS thin films. PEDOT:PSS is a polymer mixture, which is electrically conductive and transparent and, therefore, is an attractive material for some optoelectronic applications, such as organic and perovskite solar cells. In this work, the films are fabricated using spin coating (a lab-scale method) and spray coating (an up-scalable method). The effects of spinning speed, drying time, and post-annealing temperature on spun-on samples and the effects of the substrate temperature and number of spray passes (deposition layers) on spray-on samples, as well as the effect of precursor solution concentration on both cases are investigated. Various characterization tools, such as AFM, SEM, XRD, confocal laser scanning microscopy (CLSM), and electrical conductivity measurements are used to determine the film roughness, thickness, structure, and morphology. The solution precursor physical data, such as contact angle on glass substrates, viscosity, and interfacial tension, are also obtained within a practical range of temperatures and concentrations. It is found that in both spin and spray coating routes, only well-controlled operating conditions result in the formation of conductive and defect-free PEDOT:PSS films. The formation of PEDOT:PSS thin films with small grains composed of PEDOT forming the core of the grains and PSS forming a shell or coating, which are evenly distributed in a PSS

  13. Morphology, conductivity, and wetting characteristics of PEDOT:PSS thin films deposited by spin and spray coating

    International Nuclear Information System (INIS)

    Zabihi, F.; Xie, Y.; Gao, S.; Eslamian, M.

    2015-01-01

    Highlights: • Nanostructure of spun-on and spray-on PEDOT:PSS thin films is studied. • A correlation is established between the film nanostructure and electrical conductivity. • Effect of process parameters is studied on the film characteristics. • A high solution concentration, high process temperature and multiple deposition layers are recommended. - Abstract: The goal of this paper is to study the characteristics of PEDOT:PSS thin films and the effects of varying the processing parameters on the structure, functionality, and surface wetting of spun-on and spray-on PEDOT:PSS thin films. PEDOT:PSS is a polymer mixture, which is electrically conductive and transparent and, therefore, is an attractive material for some optoelectronic applications, such as organic and perovskite solar cells. In this work, the films are fabricated using spin coating (a lab-scale method) and spray coating (an up-scalable method). The effects of spinning speed, drying time, and post-annealing temperature on spun-on samples and the effects of the substrate temperature and number of spray passes (deposition layers) on spray-on samples, as well as the effect of precursor solution concentration on both cases are investigated. Various characterization tools, such as AFM, SEM, XRD, confocal laser scanning microscopy (CLSM), and electrical conductivity measurements are used to determine the film roughness, thickness, structure, and morphology. The solution precursor physical data, such as contact angle on glass substrates, viscosity, and interfacial tension, are also obtained within a practical range of temperatures and concentrations. It is found that in both spin and spray coating routes, only well-controlled operating conditions result in the formation of conductive and defect-free PEDOT:PSS films. The formation of PEDOT:PSS thin films with small grains composed of PEDOT forming the core of the grains and PSS forming a shell or coating, which are evenly distributed in a PSS

  14. The structural properties of CdS deposited by chemical bath deposition and pulsed direct current magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Lisco, F., E-mail: F.Lisco@lboro.ac.uk [Centre for Renewable Energy Systems Technology (CREST), School of Electronic, Electrical and Systems Engineering, Loughborough University, Leicestershire, LE11 3TU (United Kingdom); Kaminski, P.M.; Abbas, A.; Bass, K.; Bowers, J.W.; Claudio, G. [Centre for Renewable Energy Systems Technology (CREST), School of Electronic, Electrical and Systems Engineering, Loughborough University, Leicestershire, LE11 3TU (United Kingdom); Losurdo, M. [Institute of Inorganic Methodologies and of Plasmas, IMIP-CNR, via Orabona 4, 70126 Bari (Italy); Walls, J.M. [Centre for Renewable Energy Systems Technology (CREST), School of Electronic, Electrical and Systems Engineering, Loughborough University, Leicestershire, LE11 3TU (United Kingdom)

    2015-05-01

    Cadmium sulphide (CdS) thin films were deposited by two different processes, chemical bath deposition (CBD), and pulsed DC magnetron sputtering (PDCMS) on fluorine doped-tin oxide coated glass to assess the potential advantages of the pulsed DC magnetron sputtering process. The structural, optical and morphological properties of films obtained by CBD and PDCMS were investigated using X-ray photoelectron spectroscopy, X-ray diffraction, scanning and transmission electron microscopy, spectroscopic ellipsometry and UV-Vis spectrophotometry. The as-grown films were studied and comparisons were drawn between their morphology, uniformity, crystallinity, and the deposition rate of the process. The highest crystallinity is observed for sputtered CdS thin films. The absorption in the visible wavelength increased for PDCMS CdS thin films, due to the higher density of the films. The band gap measured for the as-grown CBD-CdS is 2.38 eV compared to 2.34 eV for PDCMS-CdS, confirming the higher density of the sputtered thin film. The higher deposition rate for PDCMS is a significant advantage of this technique which has potential use for high rate and low cost manufacturing. - Highlights: • Pulsed DC magnetron sputtering (PDCMS) of CdS films • Chemical bath deposition of CdS films • Comparison between CdS thin films deposited by chemical bath and PDCMS techniques • High deposition rate deposition for PDCMS deposition • Uniform, pinhole free CdS thin films.

  15. The structural properties of CdS deposited by chemical bath deposition and pulsed direct current magnetron sputtering

    International Nuclear Information System (INIS)

    Lisco, F.; Kaminski, P.M.; Abbas, A.; Bass, K.; Bowers, J.W.; Claudio, G.; Losurdo, M.; Walls, J.M.

    2015-01-01

    Cadmium sulphide (CdS) thin films were deposited by two different processes, chemical bath deposition (CBD), and pulsed DC magnetron sputtering (PDCMS) on fluorine doped-tin oxide coated glass to assess the potential advantages of the pulsed DC magnetron sputtering process. The structural, optical and morphological properties of films obtained by CBD and PDCMS were investigated using X-ray photoelectron spectroscopy, X-ray diffraction, scanning and transmission electron microscopy, spectroscopic ellipsometry and UV-Vis spectrophotometry. The as-grown films were studied and comparisons were drawn between their morphology, uniformity, crystallinity, and the deposition rate of the process. The highest crystallinity is observed for sputtered CdS thin films. The absorption in the visible wavelength increased for PDCMS CdS thin films, due to the higher density of the films. The band gap measured for the as-grown CBD-CdS is 2.38 eV compared to 2.34 eV for PDCMS-CdS, confirming the higher density of the sputtered thin film. The higher deposition rate for PDCMS is a significant advantage of this technique which has potential use for high rate and low cost manufacturing. - Highlights: • Pulsed DC magnetron sputtering (PDCMS) of CdS films • Chemical bath deposition of CdS films • Comparison between CdS thin films deposited by chemical bath and PDCMS techniques • High deposition rate deposition for PDCMS deposition • Uniform, pinhole free CdS thin films

  16. Photoluminescence properties of poly (p-phenylene vinylene) films deposited by chemical vapor deposition

    International Nuclear Information System (INIS)

    Gedelian, Cynthia A.; Rajanna, K.C.; Premerlani, Brian; Lu, Toh-Ming

    2014-01-01

    Photoluminescence spectra of PPV at varying thicknesses and temperatures have been studied. A study of the quenching of the polymer film using a modified version of fluorescence spectroscopy reveals interface effects dominating at thicknesses below about 600 Å, while bulk effects dominate at higher thicknesses. The application of the Stern–Volmer equation to solid film is discussed. Stern–Volmer plots were nonlinear with downward deviations at higher thickness of the film which was explained due to self-quenching in films and larger conformational change and increased restriction from change in electron density due to electron transition during excitation in bulk polymer films over 60 nm thick. PPV deposited into porous (∼4 nm in diameter) nanostructured substrate shows a larger 0–0 than 0–1 transition peak intensity and decreased disorder in the films due to structure imposed by substrate matrix. Temperature dependent effects are measured for a film at 500 Å, right on the border between the two areas. PPV films deposited on porous methyl silsesquioxane (MSQ) were also examined in order to compare the flat film to a substrate that allows for the domination of interface effects. The enthalpies of the first two peaks are very similar, but the third peak demonstrates a lower enthalpy and a larger wavelength shift with temperature. Films deposited inside pores show a smaller amount of disorder than flat films. Calculation of the Huang–Rhys factor at varying temperatures for the flat film and film in porous MSQ shows large temperature dependence for the flat film but a smaller amount of disorder in the nanostructured film. -- Highlights: • Poly (p-phenylene vinylene) films deposited by chemical vapor deposition exhibited photoluminescence properties. • Fluorescence spectra of the polymer films revealed interface effects dominating at thicknesses below about 600 Å, while bulk effects dominate at higher thicknesses. • Stern–Volmer plots were

  17. Low-temperature wafer direct bonding of silicon and quartz glass by a two-step wet chemical surface cleaning

    Science.gov (United States)

    Wang, Chenxi; Xu, Jikai; Zeng, Xiaorun; Tian, Yanhong; Wang, Chunqing; Suga, Tadatomo

    2018-02-01

    We demonstrate a facile bonding process for combining silicon and quartz glass wafers by a two-step wet chemical surface cleaning. After a post-annealing at 200 °C, strong bonding interfaces with no defects or microcracks were obtained. On the basis of the detailed surface and bonding interface characterizations, the bonding mechanism was explored and discussed. The amino groups terminated on the cleaned surfaces might contribute to the bonding strength enhancement during the annealing. This cost-effective bonding process has great potentials for silicon- and glass-based heterogeneous integrations without requiring a vacuum system.

  18. A simple wet chemical method for the determination of cation stoichiometry of YBa2Cu3O7-d

    International Nuclear Information System (INIS)

    Sahasranaman, S.; Premila, M.; Sreedharan, O.M.

    1996-01-01

    A comprehensive wet chemical procedure for the rapid analysis of yttrium, barium and copper ions in dilute HNO 3 medium has been developed to facilitate a precise and accurate determination of cation non-stoichiometry in high temperature ceramic superconducting materials Y 1±x Ba 2±y Cu 3±z O 7-d . The ease of analysis for copper by electrogravimetry and of yttrium and barium by a complexometric titration of the same aliquot against complexone III using arsenazo I as the indicator under appropriate pH has been demonstrated with the help of individual standard solutions and with synthetic mixtures. (author)

  19. Chemical vapor deposited fiber coatings and chemical vapor infiltrated ceramic matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Kmetz, M.A.

    1992-01-01

    Conventional Chemical Vapor Deposition (CVD) and Organometallic Chemical Vapor Deposition (MOCVD) were employed to deposit a series of interfacial coatings on SiC and carbon yarn. Molybdenum, tungsten and chromium hexacarbonyls were utilized as precursors in a low temperature (350[degrees]C) MOCVD process to coat SiC yarn with Mo, W and Cr oxycarbides. Annealing studies performed on the MoOC and WOC coated SiC yarns in N[sub 2] to 1,000[degrees]C establish that further decomposition of the oxycarbides occurred, culminating in the formation of the metals. These metals were then found to react with Si to form Mo and W disilicide coatings. In the Cr system, heating in N[sub 2] above 800[degrees]C resulted in the formation of a mixture of carbides and oxides. Convention CVD was also employed to coat SiC and carbon yarn with C, Bn and a new interface designated BC (a carbon-boron alloy). The coated tows were then infiltrated with SiC, TiO[sub 2], SiO[sub 2] and B[sub 4]C by a chemical vapor infiltration process. The B-C coatings were found to provide advantageous interfacial properties over carbon and BN coatings in several different composite systems. The effectiveness of these different coatings to act as a chemically inert barrier layer and their relationship to the degree of interfacial debonding on the mechanical properties of the composites were examined. The effects of thermal stability and strength of the coated fibers and composites were also determined for several difference atmospheres. In addition, a new method for determining the tensile strength of the as-received and coated yarns was also developed. The coated fibers and composites were further characterized by AES, SEM, XPS, IR and X-ray diffraction analysis.

  20. Deposition of highly (111)-oriented PZT thin films by using metal organic chemical deposition

    CERN Document Server

    Bu, K H; Choi, D K; Seong, W K; Kim, J D

    1999-01-01

    Lead zirconate titanate (PZT) thin films have been grown on Pt/Ta/SiNx/Si substrates by using metal organic chemical vapor deposition with Pb(C sub 2 H sub 5) sub 4 , Zr(O-t-C sub 4 H sub 9) sub 4 , and Ti(O-i-C sub 3 H sub 7) sub 4 as source materials and O sub 2 as an oxidizing gas. The Zr fraction in the thin films was controlled by varying the flow rate of the Zr source material. The crystal structure and the electrical properties were investigated as functions of the composition. X-ray diffraction analysis showed that at a certain range of Zr fraction, highly (111)-oriented PZT thin films with no pyrochlore phases were deposited. On the other hand, at low Zr fractions, there were peaks from Pb-oxide phases. At high Zr fractions, peaks from pyrochlore phase were seen. The films also showed good electrical properties, such as a high dielectric constant of more than 1200 and a low coercive voltage of 1.35 V.

  1. Diamond-like carbon films deposited on polycarbonates by plasma-enhanced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Guo, C.T. [Department of Computer and Communication, Diwan College of Management, 72141 Taiwan (China)], E-mail: ctguo@dwu.edu.tw

    2008-04-30

    Diamond-like carbon films were coated on optical polycarbonate using plasma-enhanced chemical vapor deposition. A mixture of SiH{sub 4} and CH{sub 4}/H{sub 2} gases was utilized to reduce the internal compressive stress of the deposited films. The structure of the DLC films was characterized as a function of film thickness using Raman spectroscopy. The dependence of G peak positions and the intensity ratio of I{sub D}/I{sub G} on the DLC film thicknesses was analyzed in detail. Other studies involving atomic force microscopy, ultraviolet visible spectrometry, and three adhesion tests were conducted. Good transparency in the visible region, and good adhesion between diamond-like carbon films and polycarbonate were demonstrated. One-time recordings before and after a DLC film was coated on compact rewritable disc substrates were analyzed as a case study. The results reveal that the diamond-like carbon film overcoating the optical polycarbonates effectively protects the storage media.

  2. Deposition barium titanate (BaTiO3) doped lanthanum with chemical solution deposition

    International Nuclear Information System (INIS)

    Iriani, Y.; Nurhadi, N.; Jamaludin, A.

    2016-01-01

    Deposition of Barium Titanate (BaTiO 3 ) thin films used Chemical Solution Deposition (CSD) method and prepared with spin coater. BaTiO 3 is doped with lanthanum, 1%, 2%, and 3%. The thermal process use annealing temperature 900°C and holding time for 3 hours. The result of characterization with x-ray diffraction (XRD) equipment show that the addition of La 3+ doped on Barium Titanate caused the change of angle diffraction.The result of refine with GSAS software shows that lanthanum have been included in the structure of BaTiO 3 . Increasing mol dopant La 3+ cause lattice parameter and crystal volume become smaller. Characterization result using Scanning Electron Microscopy (SEM) equipment show that grain size (grain size) become smaller with increasing mole dopant (x) La 3+ . The result of characterization using Sawyer Tower methods show that all the samples (Barium Titanante and Barium Titanate doped lanthanum) are ferroelectric material. Increasing of mole dopant La 3+ cause smaller coercive field and remanent polarization increases. (paper)

  3. Plasma-enhanced chemical vapor deposition for YBCO film fabrication of superconducting fault-current limiter

    Energy Technology Data Exchange (ETDEWEB)

    Jun, Byung Hyuk; Kim, Chan Joong

    2006-05-15

    Since the high-temperature superconductor of oxide type was founded, many researches and efforts have been performed for finding its application field. The YBCO superconducting film fabricated on economic metal substrate with uniform critical current density is considered as superconducting fault-current limiter (SFCL). There are physical and chemical processes to fabricate superconductor film, and it is understood that the chemical methods are more economic to deposit large area. Among them, chemical vapor deposition (CVD) is a promising deposition method in obtaining film uniformity. To solve the problems due to the high deposition temperature of thermal CVD, plasma-enhanced chemical vapor deposition (PECVD) is suggested. This report describes the principle and fabrication trend of SFCL, example of YBCO film deposition by PECVD method, and principle of plasma deposition.

  4. Laser diagnostics of a diamond depositing chemical vapour deposition gas-phase environment

    Energy Technology Data Exchange (ETDEWEB)

    Smith, James Anthony

    2002-07-01

    Studies have been carried out to understand the gas-phase chemistry underpinning diamond deposition in hot filament and DC-arcjet chemical vapour deposition (CVD) systems. Resonance enhanced Multiphoton lonisation (REMPI) techniques were used to measure the relative H atom and CH{sub 3} radical number densities and local gas temperatures prevalent in a hot filament reactor, operating on Ch{sub 4}/H{sub 2} and C{sub 2}H{sub 2}/H{sub 2} gas mixtures. These results were compared to a 3D-computer simulation, and hence provided an insight into the nature of the gas-phase chemistry with particular reference to C{sub 2}{yields}C{sub 1} species conversion. Similar experimental and theoretical studies were also carried out to explain the chemistry involved in NH{sub 3}/CH{sub 4}/H{sub 2} and N{sub 2}/CH{sub 4}/H{sub 2} gas mixtures. It was demonstrated that the reactive nature of the filament surface was dependent on the addition of NH{sub 3}, influencing atomic hydrogen production, and thus the H/C/N gas-phase chemistry. Studies of the DC-arcjet diamond CVD reactor consisted of optical emission spectroscopic studies of the plume during deposition from an Ar/H{sub 2}/CH{sub 4}/N{sub 2} gas mixture. Spatially resolved species emission intensity maps were obtained for C{sub 2}(d{yields}a), CN(B{yields}X) and H{sub {beta}} from Abel-inverted datasets. The C{sub 2}(d{yields}a) and CN(B{yields}X) emission intensity maps both show local maxima near the substrate surface. SEM and Laser Raman analyses indicate that N{sub 2} additions lead to a reduction in film quality and growth rate. Photoluminescence and SIMS analyses of the grown films provide conclusive evidence of nitrogen incorporation (as chemically bonded CN). Absolute column densities of C{sub 2}(a) in a DC-arcjet reactor operating on an Ar/H{sub 2}/CH{sub 4} gas mixture, were measured using Cavity ring down spectroscopy. Simulations of the measured C{sub 2}(v=0) transition revealed a rotational temperature of {approx

  5. Laser diagnostics of a diamond depositing chemical vapour deposition gas-phase environment

    International Nuclear Information System (INIS)

    Smith, James Anthony

    2002-01-01

    Studies have been carried out to understand the gas-phase chemistry underpinning diamond deposition in hot filament and DC-arcjet chemical vapour deposition (CVD) systems. Resonance enhanced Multiphoton lonisation (REMPI) techniques were used to measure the relative H atom and CH 3 radical number densities and local gas temperatures prevalent in a hot filament reactor, operating on Ch 4 /H 2 and C 2 H 2 /H 2 gas mixtures. These results were compared to a 3D-computer simulation, and hence provided an insight into the nature of the gas-phase chemistry with particular reference to C 2 →C 1 species conversion. Similar experimental and theoretical studies were also carried out to explain the chemistry involved in NH 3 /CH 4 /H 2 and N 2 /CH 4 /H 2 gas mixtures. It was demonstrated that the reactive nature of the filament surface was dependent on the addition of NH 3 , influencing atomic hydrogen production, and thus the H/C/N gas-phase chemistry. Studies of the DC-arcjet diamond CVD reactor consisted of optical emission spectroscopic studies of the plume during deposition from an Ar/H 2 /CH 4 /N 2 gas mixture. Spatially resolved species emission intensity maps were obtained for C 2 (d→a), CN(B→X) and H β from Abel-inverted datasets. The C 2 (d→a) and CN(B→X) emission intensity maps both show local maxima near the substrate surface. SEM and Laser Raman analyses indicate that N 2 additions lead to a reduction in film quality and growth rate. Photoluminescence and SIMS analyses of the grown films provide conclusive evidence of nitrogen incorporation (as chemically bonded CN). Absolute column densities of C 2 (a) in a DC-arcjet reactor operating on an Ar/H 2 /CH 4 gas mixture, were measured using Cavity ring down spectroscopy. Simulations of the measured C 2 (v=0) transition revealed a rotational temperature of ∼3300 K. This gas temperature is similar to that deduced from optical emission spectroscopy studies of the C 2 (d→a) transition. (author)

  6. SiC fibre by chemical vapour deposition on tungsten filament

    Indian Academy of Sciences (India)

    Unknown

    SiC fibre by chemical vapour deposition on tungsten filament ... CMCs), in defence and industrial applications. SiC has attractive ... porosity along with chemical purity. This is lacking .... reactor. Since mercury is very toxic it should be removed.

  7. Continental-scale assessment of long-term trends in wet deposition trajectories: Role of anthropogenic and hydro-climatic drivers

    Science.gov (United States)

    Park, J.; Gall, H. E.; Niyogi, D.; Rao, S.

    2012-12-01

    The global trend of increased urbanization, and associated increased intensity of energy and material consumption and waste emissions, has contributed to shifts in the trajectories of aquatic, terrestrial, and atmospheric environments. Here, we focus on continental-scale spatiotemporal patterns in two atmospheric constituents (nitrate and sulfate), whose global biogeochemical cycles have been dramatically altered by emissions from mobile and fixed sources in urbanized and industrialized regions. The observed patterns in wet deposition fluxes of nitrate and sulfate are controlled by (1) natural hydro-climatic forcing, and (2) anthropogenic forcing (emissions and regulatory control), both of which are characterized by stochasticity and non-stationarity. We examine long-term wet deposition records in the U.S., Europe, and East Asia to evaluate how anthropogenic and natural forcing factors jointly contributed to the shifting temporal patterns of wet deposition fluxes at continental scales. These data offer clear evidence for successful implementation of regulatory controls and widespread adoption of technologies contributed to improving water quality and mitigation of adverse ecological impacts. We developed a stochastic model to project the future trajectories of wet deposition fluxes in emerging countries with fast growing urban areas. The model generates ellipses within which projected wet deposition flux trajectories are inscribed, similar to the trends in observational data. The shape of the ellipses provides information regarding the relative dominance of anthropogenic (e.g., industrial and urban emissions) versus hydro-climatic drivers (e.g., rainfall patterns, aridity index). Our analysis facilitates projections of the trajectory shift as a result of urbanization and other land-use changes, climate change, and regulatory enforcement. We use these observed data and the model to project likely trajectories for rapidly developing countries (BRIC), with a

  8. Temperature dependence of morphology, structural and optical properties of ZnS nanostructures synthesized by wet chemical route

    International Nuclear Information System (INIS)

    Navaneethan, M.; Archana, J.; Nisha, K.D.; Hayakawa, Y.; Ponnusamy, S.; Muthamizhchelvan, C.

    2010-01-01

    Research highlights: → ZnS nanoparticles and nanorods have been synthesized by wet chemical route. → Higher annealing temperature influenced the change in morphology due to aggregation of the nanoparticles. → The temperature dependent optical properties were investigated. → Absorption edge of nanoparticles (295 nm) and nanorods (326 nm) were shifted towards shorter wavelength compared to bulk ZnS (337 nm) due to the quantum confinement effect. → ZnS nanoparticles exhibit high photoluminescence intensity than that of ZnS nanorods annealed at 180 o C. - Abstract: ZnS nanostructures have been synthesized by simple wet chemical route and annealed at two different temperatures of 50 o C and 180 o C. From the measurements of transmission electron microscopy and contact-mode atomic force microscopy, it is found that annealed temperature changes the morphology from nanoparticles to nanorods. The optical properties of the synthesized ZnS nanomaterial have been characterized by UV-visible absorption spectroscopy and photoluminescence spectroscopy. The structural and elemental analyses were carried out by powder X-ray diffraction pattern and energy dispersive X-ray absorption spectroscopy, respectively. Absorption edge of the nanoparticles (295 nm) and nanorods (326 nm) was shifted towards shorter wavelength compared to bulk ZnS (337 nm) due to the quantum confinement effect.

  9. Fabrication of Cu{sub 2}S nanoneedles by self-assembly of nanoparticles via simple wet chemical route

    Energy Technology Data Exchange (ETDEWEB)

    Kumarakuru, Haridas, E-mail: haridas.kumarakuru@nmmu.ac.za; Coombes, Matthew J.; Neethling, Johannes H.; Westraadt, Johan E.

    2014-03-15

    Highlights: • An inexpensive wet chemical method was used at room temperature to grow Cu{sub 2}S. • Growth of Cu{sub 2}S nanostructures influences by the Cl{sup −} ion concentration. • Thioglycerol and Cl{sup −} ions are used as a blend capping agents. • Cu{sub 2}S nanoneedles were formed via self-assembly of nanoparticles. • We can propose a growth model for Cu{sub 2}S nanoneedles based on our observations. -- Abstract: Cu{sub 2}S nanoneedles, fabricated by self-assembly of Cu{sub 2}S nanoparticles via wet chemical method are investigated. Crystallinity and surface morphologies of the as-grown needles are examined using X-ray diffraction and scanning and transmission electron microscopy. It is observed that the nanoparticle formation is controlled by the blend concentration of capping agents, thioglycerol, added during the synthesis and the Cl{sup −} ions delivered by the CuCl source. The likely reasons for the elongated structure of the nanoparticle self-assembly are also discussed.

  10. Wet oxidative degradation of cellulosic wastes 5- chemical and thermal properties of the final waste forms

    International Nuclear Information System (INIS)

    Eskander, S.B.; Saleh, H.M.

    2002-01-01

    In this study, the residual solution arising from the wet oxidative degradation of solid organic cellulosic materials, as one of the component of radioactive solid wastes, using hydrogen peroxide as oxidant. Were incorporated into ordinary Portland cement matrix. Leaching as well as thermal characterizations of the final solidified waste forms were evaluated to meet the final disposal requirements. Factors, such as the amount of the residual solution incorporated, types of leachant. Release of different radionuclides and freezing-thaw treatment, that may affect the leaching characterization. Were studied systematically from the data obtained, it was found that the final solid waste from containing 35% residual solution in tap water is higher than that in ground water or sea water. Based on the data obtained from thermal analysis, it could be concluded that incorporating the residual solution form the wet oxidative degradation of cellulosic materials has no negative effect on the hydration of cement materials and consequently on the thermal stability of the final solid waste from during the disposal process

  11. Formation of amorphous metal alloys by chemical vapor deposition

    Science.gov (United States)

    Mullendore, A.W.

    1988-03-18

    Amorphous alloys are deposited by a process of thermal dissociation of mixtures of organometallic compounds and metalloid hydrides,e.g., transition metal carbonyl, such as nickel carbonyl and diborane. Various sizes and shapes of deposits can be achieved, including near-net-shape free standing articles, multilayer deposits, and the like. Manipulation or absence of a magnetic field affects the nature and the structure of the deposit. 1 fig.

  12. Chemical vapor deposition growth of two-dimensional heterojunctions

    Science.gov (United States)

    Cui, Yu; Li, Bo; Li, JingBo; Wei, ZhongMing

    2018-01-01

    The properties of two-dimensional (2D) layered materials with atom-smooth surface and special interlayer van der Waals coupling are different from those of traditional materials. Due to the absence of dangling bonds from the clean surface of 2D layered materials, the lattice mismatch influences slightly on the growth of 2D heterojunctions, thus providing a flexible design strategy. 2D heterojunctions have attracted extensive attention because of their excellent performance in optoelectronics, spintronics, and valleytronics. The transfer method was utilized for the fabrication of 2D heterojunctions during the early stage of fundamental research on these materials. This method, however, has limited practical applications. Therefore, chemical vapor deposition (CVD) method was recently developed and applied for the preparation of 2D heterojunctions. The CVD method is a naturally down-top growth strategy that yields 2D heterojunctions with sharp interfaces. Moreover, this method effectively reduces the introduction of contaminants to the fabricated heterojunctions. Nevertheless, the CVD-growth method is sensitive to variations in growth conditions. In this review article, we attempt to provide a comprehensive overview of the influence of growth conditions on the fabrication of 2D heterojunctions through the direct CVD method. We believe that elucidating the effects of growth conditions on the CVD method is necessary to help control and improve the efficiency of the large-scale fabrication of 2D heterojunctions for future applications in integrated circuits.

  13. Long distance spin communication in chemical vapour deposited graphene

    Science.gov (United States)

    Kamalakar, M. Venkata; Groenveld, Christiaan; Dankert, André; Dash, Saroj P.

    2015-04-01

    Graphene is an ideal medium for long-distance spin communication in future spintronic technologies. So far, the prospect is limited by the smaller sizes of exfoliated graphene flakes and lower spin transport properties of large-area chemical vapour-deposited (CVD) graphene. Here we demonstrate a high spintronic performance in CVD graphene on SiO2/Si substrate at room temperature. We show pure spin transport and precession over long channel lengths extending up to 16 μm with a spin lifetime of 1.2 ns and a spin diffusion length ~6 μm at room temperature. These spin parameters are up to six times higher than previous reports and highest at room temperature for any form of pristine graphene on industrial standard SiO2/Si substrates. Our detailed investigation reinforces the observed performance in CVD graphene over wafer scale and opens up new prospects for the development of lateral spin-based memory and logic applications.

  14. Mineralogical and chemical characteristics of marble of Bela Pola deposite

    International Nuclear Information System (INIS)

    Shijakova-Ivanova, Tena; Boev, Blazho; Panov, Zoran; Pavlov, Dejan

    2009-01-01

    This paper presents mineralogical characteristics of marbles from the Bela Pola deposit. We have made mineralogical-chemical analyses of marbles and associated minerals in them. The investigation was carried out at the Faculty of natural and technical sciences - Shtip. Marbles from Bela Pola are dolomite and dolomite-calcite types. Microscope investigations have shown that marbles from Bela Pola have granoblastic structure but at some places it can be found with porphyroblastic structures. Percentage on calcite and dolomite is: 94.08% dolomite, 6.25% is calcite in white marbles. On the other hand calcite is present with 93% in gray marbles. Except dolomite and calcite also appear the following accessoring minerals: quartz, fluorite, corundum and paragonite. In general, after summarizing all the facts, which have resulted from this research we could say that, the Bela Pola marbles are massive, compact and white with high quality. In accordance to all formerly mentioned features, this marbles can be classified in the commercial group of marbles suitable for external application or internal design

  15. Review: Plasma-enhanced chemical vapor deposition of nanocrystalline diamond

    Directory of Open Access Journals (Sweden)

    Katsuyuki Okada

    2007-01-01

    Full Text Available Nanocrystalline diamond films have attracted considerable attention because they have a low coefficient of friction and a low electron emission threshold voltage. In this paper, the author reviews the plasma-enhanced chemical vapor deposition (PE-CVD of nanocrystalline diamond and mainly focuses on the growth of nanocrystalline diamond by low-pressure PE-CVD. Nanocrystalline diamond particles of 200–700 nm diameter have been prepared in a 13.56 MHz low-pressure inductively coupled CH4/CO/H2 plasma. The bonding state of carbon atoms was investigated by ultraviolet-excited Raman spectroscopy. Electron energy loss spectroscopy identified sp2-bonded carbons around the 20–50 nm subgrains of nanocrystalline diamond particles. Plasma diagnostics using a Langmuir probe and the comparison with plasma simulation are also reviewed. The electron energy distribution functions are discussed by considering different inelastic interaction channels between electrons and heavy particles in a molecular CH4/H2 plasma.

  16. Growth of graphene underlayers by chemical vapor deposition

    International Nuclear Information System (INIS)

    Fabiane, Mopeli; Khamlich, Saleh; Bello, Abdulhakeem; Dangbegnon, Julien; Momodu, Damilola; Manyala, Ncholu; Charlie Johnson, A. T.

    2013-01-01

    We present a simple and very convincing approach to visualizing that subsequent layers of graphene grow between the existing monolayer graphene and the copper catalyst in chemical vapor deposition (CVD). Graphene samples were grown by CVD and then transferred onto glass substrates by the bubbling method in two ways, either direct-transfer (DT) to yield poly (methyl methacrylate) (PMMA)/graphene/glass or (2) inverted transfer (IT) to yield graphene/PMMA/glass. Field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM) were used to reveal surface features for both the DT and IT samples. The results from FE-SEM and AFM topographic analyses of the surfaces revealed the underlayer growth of subsequent layers. The subsequent layers in the IT samples are visualized as 3D structures, where the smaller graphene layers lie above the larger layers stacked in a concentric manner. The results support the formation of the so-called “inverted wedding cake” stacking in multilayer graphene growth

  17. Intelligent process control of fiber chemical vapor deposition

    Science.gov (United States)

    Jones, John Gregory

    Chemical Vapor Deposition (CVD) is a widely used process for the application of thin films. In this case, CVD is being used to apply a thin film interface coating to single crystal monofilament sapphire (Alsb2Osb3) fibers for use in Ceramic Matrix Composites (CMC's). The hot-wall reactor operates at near atmospheric pressure which is maintained using a venturi pump system. Inert gas seals obviate the need for a sealed system. A liquid precursor delivery system has been implemented to provide precise stoichiometry control. Neural networks have been implemented to create real-time process description models trained using data generated based on a Navier-Stokes finite difference model of the process. Automation of the process to include full computer control and data logging capability is also presented. In situ sensors including a quadrupole mass spectrometer, thermocouples, laser scanner, and Raman spectrometer have been implemented to determine the gas phase reactants and coating quality. A fuzzy logic controller has been developed to regulate either the gas phase or the in situ temperature of the reactor using oxygen flow rate as an actuator. Scanning electron microscope (SEM) images of various samples are shown. A hierarchical control structure upon which the control structure is based is also presented.

  18. Long-term atmospheric wet deposition of dissolved organic nitrogen in a typical red-soil agro-ecosystem, Southeastern China.

    Science.gov (United States)

    Cui, Jian; Zhou, Jing; Peng, Ying; He, Yuan Q; Yang, Hao; Xu, Liang J; Chan, Andy

    2014-05-01

    Dissolved organic nitrogen (DON) from atmospheric deposition has been a growing concern in the world and atmospheric nitrogen (N) deposition is increasing quickly in China especially Southeastern China. In our study, DON wet deposition was estimated by collecting and analyzing rainwater samples continuously over eight years (2005-2012) in a typical red-soil farmland ecosystem, Southeast China. Results showed that the volume-weighted-average DON concentration varied from 0.2 to 3.3 mg N L(-1) with an average of 1.2 mg N L(-1). DON flux ranged from 5.7 to 71.6 kg N ha(-1) year(-1) and averaged 19.7 kg N ha(-1) year(-1) which accounted for 34.6% of the total dissolved nitrogen (TDN) in wet deposition during the eight-year period. Analysis of DON concentration and flux, contribution of DON to TDN, rainfall, rain frequency, air temperature and wind frequency and the application of pig manure revealed possible pollution sources. Significant positive linear relation of annual DON flux and usage of pig manure (Pcycle in the red-soil agro-ecosystem in the future.

  19. ZnO based nanowires grown by chemical vapour deposition for selective hydrogenation of acetylene alcohols

    NARCIS (Netherlands)

    Protasova, L.N.; Rebrov, E.; Choy, K.L.; Pung, S.Y.; Engels, V.; Cabaj, M.; Wheatley, A.E.H.; Schouten, J.C.

    2011-01-01

    Vertically aligned ZnO nanowires (NWs) with a length of 1.5–10 µm and a mean diameter of ca. 150 nm were grown by chemical vapour deposition onto a c-oriented ZnO seed layer which was deposited by atomic layer deposition on Si substrates. The substrates were then spin-coated with an ethanol solution

  20. Chemical solution deposition of CaCu 3 Ti 4 O 12 thin film

    Indian Academy of Sciences (India)

    CaCu3Ti4O12 (CCTO) thin film was successfully deposited on boron doped silica substrate by chemical solution deposition and rapid thermal processing. The phase and microstructure of the deposited films were studied as a function of sintering temperature, employing X-ray diffractometry and scanning electron ...

  1. Wet chemical treatment of boron doped emitters on n-type (1 0 0) c-Si prior to amorphous silicon passivation

    Energy Technology Data Exchange (ETDEWEB)

    Meddeb, H., E-mail: hosny.meddeb@gmail.com [KACST-Intel Consortium Center of Excellence in Nano-manufacturing Applications (CENA), Riyadh (Saudi Arabia); IMEC, Kapeldreef 75, B-3001 Leuven (Belgium); Research and Technology Center of Energy, Photovoltaic Department, Borj-Cedria Science and Technology Park, BP 95, 2050 (Tunisia); University of Carthage, Faculty of Sciences of Bizerta (Tunisia); Bearda, T.; Recaman Payo, M.; Abdelwahab, I. [IMEC, Kapeldreef 75, B-3001 Leuven (Belgium); Abdulraheem, Y. [Electrical Engineering Department, College of Engineering & Petroleum, Kuwait University, P.O. Box 5969, 13060 Safat (Kuwait); Ezzaouia, H. [Research and Technology Center of Energy, Photovoltaic Department, Borj-Cedria Science and Technology Park, BP 95, 2050 (Tunisia); Gordon, I.; Szlufcik, J. [IMEC, Kapeldreef 75, B-3001 Leuven (Belgium); Poortmans, J. [IMEC, Kapeldreef 75, B-3001 Leuven (Belgium); Department of Electrical Engineering (ESAT), K.U. Leuven, 3001 Leuven (Belgium); Faculty of Sciences, University of Hasselt, Martelarenlaan 42, 3500 Hasselt (Belgium)

    2015-02-15

    Highlights: • The influence of the cleaning process using different HF-based cleaning on the amorphous silicon passivation of homojunction boron doped emitters is analyzed. • The effect of boron doping level on surface characteristics after wet chemical cleaning: For heavily doped surfaces, the reduction in contact angle was less pronounced, which proves that such surfaces are more resistant to oxide formation and remain hydrophobic for a longer time. In the case of low HF concentration, XPS measurements show higher oxygen concentrations for samples with higher doping level, probably due to the incomplete removal of the native oxide. • Higher effective lifetime is achieved at lower doping for all considered different chemical pre-treatments. • A post-deposition annealing improves the passivation level yielding emitter saturation currents determined by Auger recombination in the order of 70 fA/cm{sup 2} and below. • The dominance of Auger recombination over other type of B-induced defects on lifetime quality in the case of our p+ emitter. - Abstract: The influence of the cleaning process on the amorphous silicon passivation of homojunction emitters is investigated. A significant variation in the passivation quality following different cleaning sequences is not observed, even though differences in cleaning performance are evident. These results point out the effectiveness of our cleaning treatment and provide a hydrogen termination for intrinsic amorphous silicon passivation. A post-deposition treatment improves the passivation level yielding emitter saturation currents determined by Auger recombination in the order of 70 fA/cm{sup 2} and below.

  2. The contact angle of wetting of the solid phase of soil before and after chemical modification

    Directory of Open Access Journals (Sweden)

    Tyugai Zemfira

    2015-07-01

    Full Text Available Wettability of soil affects a wide variety of processes including infiltration, preferential flow and surface runoff. Wettability of surface is usually expressed in terms of contact angle (CA measurement. If the CA between liquid and solid surface is less than 90°, the surface is called hydrophilic, otherwise the surface is called hydrophobic. If the CA of water droplet on hydrophilic surface is in a range of 0-30° this surface is called superhydrophilic. In case of superhydrophobic surfaces the CA exceeds 150° that means that these surfaces are extremely difficult to wet. CA of wetting of mineral soil particles depends on the overlying organic and iron compounds. The object of study is a sample of the humus-accumulative horizon of typical chernozem (Kursk, Russia and two samples (horizons A1, B2 of red ferrallitic soils (Fr. Norfolk, NE Oceania. The soil samples were analyzed for organic carbon, forms of non-silicate iron and hydrophobic-hydrophilic composition of humic substances. CA of wetting was determined in the intact samples and after removal of organic matter (H2O2 treatment, amorphous and crystallized forms of iron. Static contact angles were determined with the sessile drop method using a digital goniometer (Drop Shape Analysis System, DSA100, Krüss GmbH, Hamburg, Germany. The contact angle was calculated by the Young–Laplace method (fitting of Young–Laplace equation to the drop shape. The measurements were repeated 10-15 times for every sample. Oxidation of organic matter (H2O2 treatment causes an increase in the values of CA of wetting (in chernozem from 9.3 to 28,0-29.5º, in ferrallitic soil from 18.0 − 27.3 to 22.4 − 33.4º. CA remained constant for chernozem and slightly decreased in the case of ferrallitic soil, when the removal of amorphous and crystallized forms of iron was performed on samples pretreated with H2O2. CA increase occurs after successive removal of nonsilicate forms of iron from soil samples of

  3. Microstructure and chemical bonding of DLC films deposited on ACM rubber by PACVD

    NARCIS (Netherlands)

    Martinez-Martinez, D.; Schenkel, M.; Pei, Y.T.; Sánchez-López, J.C.; Hosson, J.Th.M. De

    2011-01-01

    The microstructure and chemical bonding of DLC films prepared by plasma assisted chemical vapor deposition on acrylic rubber (ACM) are studied in this paper. The temperature variation produced by the ion impingement during plasma cleaning and subsequent film deposition was used to modify the film

  4. Chemical bath deposited and dip coating deposited CuS thin films - Structure, Raman spectroscopy and surface study

    Science.gov (United States)

    Tailor, Jiten P.; Khimani, Ankurkumar J.; Chaki, Sunil H.

    2018-05-01

    The crystal structure, Raman spectroscopy and surface microtopography study on as-deposited CuS thin films were carried out. Thin films deposited by two techniques of solution growth were studied. The thin films used in the present study were deposited by chemical bath deposition (CBD) and dip coating deposition techniques. The X-ray diffraction (XRD) analysis of both the as-deposited thin films showed that both the films possess covellite phase of CuS and hexagonal unit cell structure. The determined lattice parameters of both the films are in agreement with the standard JCPDS as well as reported data. The crystallite size determined by Scherrer's equation and Hall-Williamsons relation using XRD data for both the as-deposited thin films showed that the respective values were in agreement with each other. The ambient Raman spectroscopy of both the as-deposited thin films showed major emission peaks at 474 cm-1 and a minor emmision peaks at 265 cm-1. The observed Raman peaks matched with the covellite phase of CuS. The atomic force microscopy of both the as-deposited thin films surfaces showed dip coating thin film to be less rough compared to CBD deposited thin film. All the obtained results are presented and deliberated in details.

  5. Ternary Ag-In-S polycrystalline films deposited using chemical bath deposition for photoelectrochemical applications

    International Nuclear Information System (INIS)

    Chang, Wen-Sheng; Wu, Ching-Chen; Jeng, Ming-Shan; Cheng, Kong-Wei; Huang, Chao-Ming; Lee, Tai-Chou

    2010-01-01

    This paper describes the preparation and characterization of ternary Ag-In-S thin films deposited on indium tin oxide (ITO)-coated glass substrates using chemical bath deposition (CBD). The composition of the thin films was varied by changing the concentration ratio of [Ag]/[In] in the precursor solutions. The crystal structure, optical properties, and surface morphology of the thin films were analyzed by grazing incidence X-ray diffraction (GIXRD), UV-vis spectroscopy, and field-emission scanning electron microscopy (FE-SEM). GIXRD results indicate that the samples consisted of AgInS 2 and/or AgIn 5 S 8 crystal phases, depending on the composition of the precursor solutions. The film thicknesses, electrical resistivity, flat band potentials, and band gaps of the samples were between 1.12 and 1.37 μm, 3.73 x 10 -3 and 4.98 x 10 4 Ω cm, -0.67 and -0.90 V vs. NHE, and 1.83 and 1.92 eV, respectively. The highest photocurrent density was observed in the sample with [Ag]/[In] = 4. A photocurrent density of 9.7 mA cm -2 was obtained with an applied potential of 0.25 V vs. SCE in the three-electrode system. The photoresponse experiments were conducted in 0.25 M K 2 SO 3 and 0.35 M Na 2 S aqueous electrolyte solutions under irradiation by a 300 W Xe light (100 mW cm -2 ). The results show that ternary Ag-In-S thin film electrodes have potential in water splitting applications.

  6. Ternary Ag-In-S polycrystalline films deposited using chemical bath deposition for photoelectrochemical applications

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Wen-Sheng [Energy and Environmental Laboratories, Industrial Technology Research Institute, 195 Sec. 4, Chung-Hsing Road, Hsin-Chu 310, Taiwan (China); Wu, Ching-Chen [Department of Chemical Engineering, National Chung Cheng University, 168 University Road, Min-Hsiung, Chia-Yi 621, Taiwan (China); Jeng, Ming-Shan [Energy and Environmental Laboratories, Industrial Technology Research Institute, 195 Sec. 4, Chung-Hsing Road, Hsin-Chu 310, Taiwan (China); Cheng, Kong-Wei [Department of Chemical and Materials Engineering, Chang Gung University, 259 Wen-Hwa 1st Road, Kwei-Shan, Tao-Yuan 333, Taiwan (China); Huang, Chao-Ming [Department of Environmental Engineering, Kun Shan University, 949 Da Wan Road, Yung-Kang City, Tainan Hsien 710, Taiwan (China); Lee, Tai-Chou, E-mail: chmtcl@ccu.edu.tw [Department of Chemical Engineering, National Chung Cheng University, 168 University Road, Min-Hsiung, Chia-Yi 621, Taiwan (China)

    2010-04-15

    This paper describes the preparation and characterization of ternary Ag-In-S thin films deposited on indium tin oxide (ITO)-coated glass substrates using chemical bath deposition (CBD). The composition of the thin films was varied by changing the concentration ratio of [Ag]/[In] in the precursor solutions. The crystal structure, optical properties, and surface morphology of the thin films were analyzed by grazing incidence X-ray diffraction (GIXRD), UV-vis spectroscopy, and field-emission scanning electron microscopy (FE-SEM). GIXRD results indicate that the samples consisted of AgInS{sub 2} and/or AgIn{sub 5}S{sub 8} crystal phases, depending on the composition of the precursor solutions. The film thicknesses, electrical resistivity, flat band potentials, and band gaps of the samples were between 1.12 and 1.37 {mu}m, 3.73 x 10{sup -3} and 4.98 x 10{sup 4} {Omega} cm, -0.67 and -0.90 V vs. NHE, and 1.83 and 1.92 eV, respectively. The highest photocurrent density was observed in the sample with [Ag]/[In] = 4. A photocurrent density of 9.7 mA cm{sup -2} was obtained with an applied potential of 0.25 V vs. SCE in the three-electrode system. The photoresponse experiments were conducted in 0.25 M K{sub 2}SO{sub 3} and 0.35 M Na{sub 2}S aqueous electrolyte solutions under irradiation by a 300 W Xe light (100 mW cm{sup -2}). The results show that ternary Ag-In-S thin film electrodes have potential in water splitting applications.

  7. Microstructures, Mechanical Properties and Thermal Conductivities of W-0.5 wt.%TiC Alloys Prepared via Ball Milling and Wet Chemical Method

    Science.gov (United States)

    Lang, Shaoting; Yan, Qingzhi; Sun, Ningbo; Zhang, Xiaoxin; Ge, Changchun

    2017-10-01

    Two kinds of W-0.5 wt.%TiC alloys were prepared, one by ball milling and the other by the wet chemical method. For comparison, pure tungsten powders were chemically prepared and sintered by the same process. The microstructures, mechanical properties and thermal conductivities of the prepared samples were characterized. It has been found that the wet chemical method resulted in finer sizes and more uniform distribution of TiC particles in the sintered tungsten matrix than the ball milling method. The W-TiC alloy prepared by the wet chemical method achieved the highest bending strength (1065.72 MPa) among the samples. Further, it also exhibited obviously higher thermal conductivities in the temperature range of room temperature to 600°C than did the W-TiC alloy prepared by ball milling, but the differences in their thermal conductivities could be ignored in the range of 600-800°C.

  8. CO gas sensing of CuO nanostructures, synthesized by an assisted solvothermal wet chemical route

    International Nuclear Information System (INIS)

    Aslani, Alireza; Oroojpour, Vahid

    2011-01-01

    CuO nanostructures with different morphologies and sizes were grown in a controlled manner using a simple low-temperature hydrothermal technique. By controlling the pH of reaction mixture, spherical nanoparticles and cloudlike CuO structures were synthesized at 100-150 o C with excellent efficiency. These CuO nanostructures have been tested for CO gas monitoring by depositing them as thick films on an interdigitated alumina substrate and evaluated the surface resistance of the deposited layer as a function of operating temperature and CO concentrations. The gas sensitivity tests have demonstrated that the CuO nanostructures, especially cloudlike morphology, exhibit high sensitivity to CO proving their applicability in gas sensors. The role of the nanostructure on the sensing properties of CuO is also discussed.

  9. Chemical Vapor-Deposited (CVD) Diamond Films for Electronic Applications

    Science.gov (United States)

    1995-01-01

    Diamond films have a variety of useful applications as electron emitters in devices such as magnetrons, electron multipliers, displays, and sensors. Secondary electron emission is the effect in which electrons are emitted from the near surface of a material because of energetic incident electrons. The total secondary yield coefficient, which is the ratio of the number of secondary electrons to the number of incident electrons, generally ranges from 2 to 4 for most materials used in such applications. It was discovered recently at the NASA Lewis Research Center that chemical vapor-deposited (CVD) diamond films have very high secondary electron yields, particularly when they are coated with thin layers of CsI. For CsI-coated diamond films, the total secondary yield coefficient can exceed 60. In addition, diamond films exhibit field emission at fields orders of magnitude lower than for existing state-of-the-art emitters. Present state-of-the-art microfabricated field emitters generally require applied fields above 5x10^7 V/cm. Research on field emission from CVD diamond and high-pressure, high-temperature diamond has shown that field emission can be obtained at fields as low as 2x10^4 V/cm. It has also been shown that thin layers of metals, such as gold, and of alkali halides, such as CsI, can significantly increase field emission and stability. Emitters with nanometer-scale lithography will be able to obtain high-current densities with voltages on the order of only 10 to 15 V.

  10. Single crystal diamond detectors grown by chemical vapor deposition

    International Nuclear Information System (INIS)

    Tuve, C.; Angelone, M.; Bellini, V.; Balducci, A.; Donato, M.G.; Faggio, G.; Marinelli, M.; Messina, G.; Milani, E.; Morgada, M.E.; Pillon, M.; Potenza, R.; Pucella, G.; Russo, G.; Santangelo, S.; Scoccia, M.; Sutera, C.; Tucciarone, A.; Verona-Rinati, G.

    2007-01-01

    The detection properties of heteropitaxial (polycrystalline, pCVD) and homoepitaxial (single crystal, scCVD) diamond films grown by microwave chemical vapor deposition (CVD) in the Laboratories of Roma 'Tor Vergata' University are reported. The pCVD diamond detectors were tested with α-particles from different sources and 12 C ions produced by 15MV Tandem accelerator at Southern National Laboratories (LNS) in Catania (Italy). pCVDs were also used to monitor 14MeV neutrons produced by the D-T plasma at Joint European Torus (JET), Culham, U.K. The limit of pCVDs is the poor energy resolution. To overcome this problem, we developed scCVD diamonds using the same reactor parameters that optimized pCVD diamonds. scCVD were grown on a low cost (100) HPHT single crystal substrate. A detector 110μm thick was tested under α-particles and under 14MeV neutron irradiation. The charge collection efficiency spectrum measured under irradiation with a triple α-particle source shows three clearly resolved peaks, with an energy resolution of about 1.1%. The measured spectra under neutron irradiation show a well separated C(n,α 0 ) 9 Be12 reaction peak with an energy spread of 0.5MeV for 14.8MeV neutrons and 0.3MeV for 14.1MeV neutrons, which are fully compatible with the energy spread of the incident neutron beams

  11. Modeling dry and wet deposition of sulfate, nitrate, and ammonium ions in Jiuzhaigou National Nature Reserve, China using a source-oriented CMAQ model: Part I. Base case model results.

    Science.gov (United States)

    Qiao, Xue; Tang, Ya; Hu, Jianlin; Zhang, Shuai; Li, Jingyi; Kota, Sri Harsha; Wu, Li; Gao, Huilin; Zhang, Hongliang; Ying, Qi

    2015-11-01

    A source-oriented Community Multiscale Air Quality (CMAQ) model driven by the meteorological fields generated by the Weather Research and Forecasting (WRF) model was used to study the dry and wet deposition of nitrate (NO3(-)), sulfate (SO4(2-)), and ammonium (NH4(+)) ions in the Jiuzhaigou National Nature Reserve (JNNR), China from June to August 2010 and to identify the contributions of different emission sectors and source regions that were responsible for the deposition fluxes. The model performance is evaluated in this paper and the source contribution analyses are presented in a companion paper. The results show that WRF is capable of reproducing the observed precipitation rates with a Mean Normalized Gross Error (MNGE) of 8.1%. Predicted wet deposition fluxes of SO4(2-) and NO3(-) at the Long Lake (LL) site (3100 m a.s.l.) during the three-month episode are 2.75 and 0.34 kg S(N) ha(-1), which agree well with the observed wet deposition fluxes of 2.42 and 0.39 kg S(N) ha(-1), respectively. Temporal variations in the weekly deposition fluxes at LL are also well predicted. Wet deposition flux of NH4(+) at LL is over-predicted by approximately a factor of 3 (1.60 kg N ha(-1)vs. 0.56 kg N ha(-1)), likely due to missing alkaline earth cations such as Ca(2+) in the current CMAQ simulations. Predicted wet deposition fluxes are also in general agreement with observations at four Acid Deposition Monitoring Network in East Asia (EANET) sites in western China. Predicted dry deposition fluxes of SO4(2-) (including gas deposition of SO2) and NO3(-) (including gas deposition of HNO3) are 0.12 and 0.12 kg S(N) h a(-1) at LL and 0.07 and 0.08 kg S(N) ha(-1) at Jiuzhaigou Bureau (JB) in JNNR, respectively, which are much lower than the corresponding wet deposition fluxes. Dry deposition flux of NH4(+) (including gas deposition of NH3) is 0.21 kg N ha(-1) at LL, and is also much lower than the predicted wet deposition flux. For both dry and wet deposition fluxes, predictions

  12. Initial evaluation of dry storage issues for spent nuclear fuels in wet storage at the Idaho Chemical Processing Plant

    Energy Technology Data Exchange (ETDEWEB)

    Guenther, R J; Johnson, Jr, A B; Lund, A L; Gilbert, E R [and others

    1996-07-01

    The Pacific Northwest Laboratory has evaluated the basis for moving selected spent nuclear fuels in the CPP-603 and CPP-666 storage pools at the Idaho Chemical Processing Plant from wet to dry interim storage. This work is being conducted for the Lockheed Idaho Technologies Company as part of the effort to determine appropriate conditioning and dry storage requirements for these fuels. These spent fuels are from 22 test reactors and include elements clad with aluminum or stainless steel and a wide variety of fuel materials: UAl{sub x}, UAl{sub x}-Al and U{sub 3}O{sub 8}-Al cermets, U-5% fissium, UMo, UZrH{sub x}, UErZrH, UO{sub 2}-stainless steel cermet, and U{sub 3}O{sub 8}-stainless steel cermet. The study also included declad uranium-zirconium hydride spent fuel stored in the CPP-603 storage pools. The current condition and potential failure mechanisms for these spent fuels were evaluated to determine the impact on conditioning and dry storage requirements. Initial recommendations for conditioning and dry storage requirements are made based on the potential degradation mechanisms and their impacts on moving the spent fuel from wet to dry storage. Areas needing further evaluation are identified.

  13. Initial evaluation of dry storage issues for spent nuclear fuels in wet storage at the Idaho Chemical Processing Plant

    International Nuclear Information System (INIS)

    Guenther, R.J.; Johnson, A.B. Jr.; Lund, A.L.; Gilbert, E.R.

    1994-11-01

    The Pacific Northwest Laboratory has evaluated the basis for moving selected spent nuclear fuels in the CPP-603 and CPP-666 storage pools at the Idaho Chemical Processing Plant from wet to dry interim storage. This work is being conducted for the Lockheed Idaho Technologies Company as part of the effort to determine appropriate conditioning and dry storage requirements for these fuels. These spent fuels are from 22 test reactors and include elements clad with aluminum or stainless steel and a wide variety of fuel materials: UAl x , UAl x -Al and U 3 O 8 -Al cermets, U-5% fissium, UMo, UZrH x , UErZrH, UO 2 -stainless steel cermet, and U 3 O 8 -stainless steel cermet. The study also included declad uranium-zirconium hydride spent fuel stored in the CPP-603 storage pools. The current condition and potential failure mechanisms for these spent fuels were evaluated to determine the impact on conditioning and dry storage requirements. Initial recommendations for conditioning and dry storage requirements are made based on the potential degradation mechanisms and their impacts on moving the spent fuel from wet to dry storage. Areas needing further evaluation are identified

  14. Validation of chemical analyses of atmospheric deposition in forested European sites

    Directory of Open Access Journals (Sweden)

    Erwin ULRICH

    2005-08-01

    Full Text Available Within the activities of the Integrated Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests and of the EU Regulation 2152/2003, a Working Group on Quality Assurance/Quality Control of analyses has been created to assist the participating laboratories in the analysis of atmospheric deposition, soil and soil solution, and leaves/needles. As part of the activity of the WG, this study is a statistical analysis in the field of water analysis of chemical concentrations and relationships between ions, and between conductivity and ions for different types of samples (bulk or wet-only samples, throughfall, stemflow considered in forest studies. About 5000 analyses from seven laboratories were used to establish relationships representative of different European geographic and climatic situations, from northern Finland to southern Italy. Statistically significant differences between the relationships obtained from different types of solutions, interacting with different types of vegetation (throughfall and stemflow samples, broad-leaved trees and conifers and with varying influence of marine salt were tested. The ultimate aim is to establish general relationships between ions, and between conductivity and ions, with relative confidence limits, which can be used as a comparison with those established in single laboratories. The use of such techniques is strongly encouraged in the ICPF laboratories to validate single chemical analyses, to be performed when it is still possible to replicate the analysis, and as a general overview of the whole set of analyses, to obtain an indication of the laboratory performance on a long-term basis.

  15. Luminescent thin films by the chemical aerosol deposition technology (CADT)

    NARCIS (Netherlands)

    Martin, F.J.; Martin, F.J.; Albers, H.; Lambeck, Paul; Popma, T.J.A.; van de Velde, G.M.H.

    1992-01-01

    Zinc sulphide thin films have been deposited with CART using zinc chlorideand zinc acetylacetonate as Zn compounds and thiourea and 1,1,3,3-tetramethylthiourea as S compounds soluted in methanol, ethanol, isopropanol and cellosolve. After optimalization of the deposition process homogeneous layers

  16. Metallorganic chemical vapor deposition and atomic layer deposition approaches for the growth of hafnium-based thin films from dialkylamide precursors for advanced CMOS gate stack applications

    Science.gov (United States)

    Consiglio, Steven P.

    To continue the rapid progress of the semiconductor industry as described by Moore's Law, the feasibility of new material systems for front end of the line (FEOL) process technologies needs to be investigated, since the currently employed polysilicon/SiO2-based transistor system is reaching its fundamental scaling limits. Revolutionary breakthroughs in complementary-metal-oxide-semiconductor (CMOS) technology were recently announced by Intel Corporation and International Business Machines Corporation (IBM), with both organizations revealing significant progress in the implementation of hafnium-based high-k dielectrics along with metal gates. This announcement was heralded by Gordon Moore as "...the biggest change in transistor technology since the introduction of polysilicon gate MOS transistors in the late 1960s." Accordingly, the study described herein focuses on the growth of Hf-based dielectrics and Hf-based metal gates using chemical vapor-based deposition methods, specifically metallorganic chemical vapor deposition (MOCVD) and atomic layer deposition (ALD). A family of Hf source complexes that has received much attention recently due to their desirable properties for implementation in wafer scale manufacturing is the Hf dialkylamide precursors. These precursors are room temperature liquids and possess sufficient volatility and desirable decomposition characteristics for both MOCVD and ALD processing. Another benefit of using these sources is the existence of chemically compatible Si dialkylamide sources as co-precursors for use in Hf silicate growth. The first part of this study investigates properties of MOCVD-deposited HfO2 and HfSixOy using dimethylamido Hf and Si precursor sources using a customized MOCVD reactor. The second part of this study involves a study of wet and dry surface pre-treatments for ALD growth of HfO2 using tetrakis(ethylmethylamido)hafnium in a wafer scale manufacturing environment. The third part of this study is an investigation of

  17. chemical and physical comparative study of the effect of wet and dry ...

    African Journals Online (AJOL)

    eobe

    The clay content of the raw clay which was 48 wt% was improved to 73 wt%. The clay content of the ... refractories and wide spectrum of ceramics [4, 5] in several industries. ... physicochemical properties, which can be determined by chemical ...

  18. Synthesis of Monodispersed Spherical Single Crystalline Silver Particles by Wet Chemical Process; Shisshiki kagakuho ni yoru tanbunsankyujo tankesshoginryushi no gose

    Energy Technology Data Exchange (ETDEWEB)

    Ueyama, Ryousuke.; Harada, Masahiro.; Ueyama, Tamotsu.; Harada, Akio. [Daiken Chemistry Industry Corporation, Osaka (Japan); Yamamoto, Takashi. [National Defence Academy, Kanagawa (Japan). Dept. of Electrical Engineering; Shiosaki, Tadashi. [Nara Institute of Science and Technology, Nara (Japan). Graduate School of Materials Science; Kuribayashi, Kiyoshi. [Teikyo University of Science and Technology, Yamanashi (Japan). Dept. of Materials

    1999-01-01

    Ultrafine silver monodispersed particle were prepared by wet chemical process. To decrease the reduction speed, an important factor in generating monodispersed particles is to control the following three factors: synthesis temperature, concentration of aggregation-relaxing agent added, and concentration of silver nitrate solution. Synthesis of monodispersed spherical Ag particles, used as metal powders for electrode, became possible using the nucleus grouwth reaction method. This process also allowed the control of the diameter of the powder particles. The silver particles were distributed in ta narrow particle diameter range with on average of 0.5 {mu}m. Transmission electron microscopy (TEM) revealed that single-crystalline silver particles were prepared by the present method. (author)

  19. Structural, optical and photocatalytic properties of flower-like ZnO nanostructures prepared by a facile wet chemical method

    Directory of Open Access Journals (Sweden)

    Sini Kuriakose

    2013-11-01

    Full Text Available Flower-like ZnO nanostructures were synthesized by a facile wet chemical method. Structural, optical and photocatalytic properties of these nanostructures have been studied by X-ray diffraction (XRD, scanning electron microscopy (SEM, transmission electron microscopy (TEM, photoluminescence (PL and UV–vis absorption spectroscopy. SEM and TEM studies revealed flower-like structures consisting of nanosheets, formed due to oriented attachment of ZnO nanoparticles. Flower-like ZnO structures showed enhanced photocatalytic activity towards sun-light driven photodegradation of methylene blue dye (MB as compared to ZnO nanoparticles. XRD, UV–vis absorption, PL, FTIR and TEM studies revealed the formation of Zn(OH2 surface layer on ZnO nanostructures upon ageing. We demonstrate that the formation of a passivating Zn(OH2 surface layer on the ZnO nanostructures upon ageing deteriorates their efficiency to photocatalytically degrade of MB.

  20. Wet-Chemical Preparation of Silicon Tunnel Oxides for Transparent Passivated Contacts in Crystalline Silicon Solar Cells.

    Science.gov (United States)

    Köhler, Malte; Pomaska, Manuel; Lentz, Florian; Finger, Friedhelm; Rau, Uwe; Ding, Kaining

    2018-05-02

    Transparent passivated contacts (TPCs) using a wide band gap microcrystalline silicon carbide (μc-SiC:H(n)), silicon tunnel oxide (SiO 2 ) stack are an alternative to amorphous silicon-based contacts for the front side of silicon heterojunction solar cells. In a systematic study of the μc-SiC:H(n)/SiO 2 /c-Si contact, we investigated selected wet-chemical oxidation methods for the formation of ultrathin SiO 2 , in order to passivate the silicon surface while ensuring a low contact resistivity. By tuning the SiO 2 properties, implied open-circuit voltages of 714 mV and contact resistivities of 32 mΩ cm 2 were achieved using μc-SiC:H(n)/SiO 2 /c-Si as transparent passivated contacts.

  1. A simple cost-effective and eco-friendly wet chemical process for the fabrication of superhydrophobic cotton fabrics

    Energy Technology Data Exchange (ETDEWEB)

    Richard, Edna; Lakshmi, R.V.; Aruna, S.T., E-mail: aruna_reddy@nal.res.in; Basu, Bharathibai J.

    2013-07-15

    Superhydrophobic surfaces were created on hydrophilic cotton fabrics by a simple wet chemical process. The fabric was immersed in a colloidal suspension of zinc hydroxide followed by subsequent hydrophobization with stearic acid. The wettability of the modified cotton fabric sample was studied by water contact angle (WCA) and water shedding angle (WSA) measurements. The modified cotton fabrics exhibited superhydrophobicity with a WCA of 151° for 8 μL water droplet and a WSA of 5–10° for 40 μL water droplet. The superhydrophobic cotton sample was also characterized by field emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectroscopy (EDX). The method is simple, eco-friendly and cost-effective and can be applied to large area of cotton fabric materials. It was shown that superhydrophobicity of the fabric was due to the combined effect of surface roughness imparted by zinc hydroxide and the low surface energy of stearic acid.

  2. A simple cost-effective and eco-friendly wet chemical process for the fabrication of superhydrophobic cotton fabrics

    International Nuclear Information System (INIS)

    Richard, Edna; Lakshmi, R.V.; Aruna, S.T.; Basu, Bharathibai J.

    2013-01-01

    Superhydrophobic surfaces were created on hydrophilic cotton fabrics by a simple wet chemical process. The fabric was immersed in a colloidal suspension of zinc hydroxide followed by subsequent hydrophobization with stearic acid. The wettability of the modified cotton fabric sample was studied by water contact angle (WCA) and water shedding angle (WSA) measurements. The modified cotton fabrics exhibited superhydrophobicity with a WCA of 151° for 8 μL water droplet and a WSA of 5–10° for 40 μL water droplet. The superhydrophobic cotton sample was also characterized by field emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectroscopy (EDX). The method is simple, eco-friendly and cost-effective and can be applied to large area of cotton fabric materials. It was shown that superhydrophobicity of the fabric was due to the combined effect of surface roughness imparted by zinc hydroxide and the low surface energy of stearic acid.

  3. Formation of hydrogen-related traps in electron-irradiated n-type silicon by wet chemical etching

    International Nuclear Information System (INIS)

    Tokuda, Yutaka; Shimada, Hitoshi

    1998-01-01

    Interaction of hydrogen atoms and vacancy-related defects in 10 MeV electron-irradiated n-type silicon has been studied by deep-level transient spectroscopy. Hydrogen has been incorporated into electron-irradiated n-type silicon by wet chemical etching. The reduction of the concentration of the vacancy-oxygen pair and divacancy occurs by the incorporation of hydrogen, while the formation of the NH1 electron trap (E c - 0.31 eV) is observed. Further decrease of the concentration of the vacancy-oxygen pair and further increase of the concentration of the NH1 trap are observed upon subsequent below-band-gap light illumination. It is suggested that the trap NH1 is tentatively ascribed to the vacancy-oxygen pair which is partly saturated with hydrogen

  4. Green synthesis of nanocrystalline α-Al2O3 powders by both wet-chemical and mechanochemical methods

    Science.gov (United States)

    Gao, Huiying; Li, Zhiyong; Zhao, Peng

    2018-03-01

    Nanosized α-Al2O3 powders were prepared with AlCl3ṡ6H2O and NH4HCO3 as raw materials by both wet-chemical and mechanochemical methods, through the synthesis of the ammonium aluminum carbonate hydroxide (AACH) precursor followed by calcination. The environmentally benign starch was used as an effective dispersant during the preparation of nanocrystalline α-Al2O3 powders. X-ray diffraction (XRD), thermogravimetric differential thermal analysis (TG-DTA), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were employed to characterize the precursor AACH and products. The results show that nanosized spherical α-Al2O3 powders without hard agglomeration and with particle size in the range of 20-40 nm can be obtained by the two methods. Comparing the two “green” processes, the mechanochemical method has better prospects for commercial production.

  5. Enhanced local piezoelectric response in the erbium-doped ZnO nanostructures prepared by wet chemical synthesis

    Directory of Open Access Journals (Sweden)

    Reza Zamiri

    2017-03-01

    Full Text Available Pure and erbium (Er doped ZnO nanostructures were prepared by simple and cost effective wet chemical precipitation method. The successful doping with phase purity of prepared ZnO nanostructure was confirmed by X-ray diffraction (XRD and their Rietveld analysis. The change in structural morphology of nanoscale features of prepared ZnO nanopowders on Er doping was observed from their scanning electron microscopy (SEM images. The presence of Er in prepared ZnO nanopowder was further confirmed from corresponding energy dispersive X-ray spectroscopy (EDX spectra of scanned SEM images. Piezoelectric properties of before (green samples and after sintering of consolidated compact of synthesized nanopowders were successfully measured. The out-of-plane (effective longitudinal and in-plane (effective shear coefficients of the samples were estimated from the local piezoresponse.

  6. Metalorganic chemical vapor deposition of gallium nitride on sacrificial substrates

    Science.gov (United States)

    Fenwick, William Edward

    GaN-based light emitting diodes (LEDs) face several challenges if the technology is to continue to make a significant impact in general illumination, and on technology that has become known as solid state lighting (SSL). Two of the most pressing challenges for the continued penetration of SSL into traditional lighting applications are efficacy and total lumens from the device, and their related cost. The development of alternative substrate technologies is a promising avenue toward addressing both of these challenges, as both GaN-based device technology and the associated metalorganic chemical vapor deposition (MOCVD) technology are already relatively mature technologies with a well-understood cost base. Zinc oxide (ZnO) and silicon (Si) are among the most promising alternative substrates for GaN epitaxy. These substrates offer the ability to access both higher efficacy and lumen devices (ZnO) at a much reduced cost. This work focuses on the development of MOCVD growth processes to yield high quality GaN-based materials and devices on both ZnO and Si. ZnO is a promising substrate for growth of low defect-density GaN because of its similar lattice constant and thermal expansion coefficient. The major hurdles for GaN growth on ZnO are the instability of the substrate in a hydrogen atmosphere, which is typical of nitride growth conditions, and the inter-diffusion of zinc and oxygen from the substrate into the GaN-based epitaxial layer. A process was developed for the MOCVD growth of GaN and InxGa 1-xN on ZnO that attempted to address these issues. The structural and optical properties of these films were studied using various techniques. X-ray diffraction (XRD) showed the growth of wurtzite GaN on ZnO, and room-temperature photoluminescence (RT-PL) showed near band-edge luminescence from the GaN and InxGa1-xN layers. However, high zinc and oxygen concentrations due to interdiffusion near the ZnO substrate remained an issue; therefore, the diffusion of zinc and oxygen

  7. Annealing effect on the photoluminescence properties of ZnO nanorod array prepared by a PLD-assistant wet chemical method

    International Nuclear Information System (INIS)

    Wei Sufeng; Lian Jianshe; Wu Hua

    2010-01-01

    Well-aligned ZnO nanorod arrays were synthesized by a wet chemical method on the glass substrate with ZnO thin film as seed layer prepared by pulsed laser deposition. The effect of annealing temperature on the luminescence characteristics was investigated. As the annealing temperature increased, the photoluminescence properties show a general enhancing tendency. The nanorod array with high ultraviolet emission and negligible visible light emission (designated by the photoluminescence intensity ratio of ultraviolet to visible emission of 66.4) is obtained by annealing the sample at 700 deg. C for 1 h. Based on the results of X-ray photoelectron spectroscopy and photoluminescence spectra, the mechanisms of visible emission were discussed. - Research Highlights: → ZnO nanorod array with good crystallography, low defects concentration and good optical property was obtained after annealed at 700 deg. C for 1 h. → The transition from the conduction band to the O i level may be responsible for the yellow-green emission. → The yellow emission may originate from the presence of Zn(OH) 2 on the surface or the band transition from conduction band to V o Zn i level. → The transition from the Zn i level to the level should produce an orange emission or an orange-red emission.

  8. Characterization of microbial and chemical composition of shuttle wet waste with permanent gas and volatile organic compound analyses

    Science.gov (United States)

    Peterson, B. V.; Hummerick, M.; Roberts, M. S.; Krumins, V.; Kish, A. L.; Garland, J. L.; Maxwell, S.; Mills, A.

    2004-01-01

    Solid-waste treatment in space for Advanced Life Support, ALS, applications requires that the material can be safely processed and stored in a confined environment. Many solid-wastes are not stable because they are wet (40-90% moisture) and contain levels of soluble organic compounds that can contribute to the growth of undesirable microorganisms with concomitant production of noxious odors. In the absence of integrated Advanced Life Support systems on orbit, permanent gas, trace volatile organic and microbiological analyses were performed on crew refuse returned from the volume F "wet" trash of three consecutive Shuttle missions (STS-105, 109, and 110). These analyses were designed to characterize the short-term biological stability of the material and assess potential crew risks resulting from microbial decay processes during storage. Waste samples were collected post-orbiter landing and sorted into packaging material, food waste, toilet waste, and bulk liquid fractions deposited during flight in the volume F container. Aerobic and anaerobic microbial loads were determined in each fraction by cultivation on R2A and by acridine orange direct count (AODC). Dry and ash weights were performed to determine both water and organic content of the materials. Experiments to determine the aerobic and anaerobic biostability of refuse stored for varying periods of time were performed by on-line monitoring of CO2 and laboratory analysis for production of hydrogen sulfide and methane. Volatile organic compounds and permanent gases were analyzed using EPA Method TO15 by USEPA et al. [EPA Method TO15, The Determination of Volatile Organic Compounds (VOCs) in Ambient Air using SUMMA, Passivated Canister Sampling and Gas Chromatographic Analysis,1999] with gas chromatography/mass spectrometry and by gas chromatography with selective detectors. These baseline measures of waste stream content, labile organics, and microbial load in the volume F Shuttle trash provide data for waste

  9. Dissolved organic nitrogen in wet deposition in a coastal city (Keelung) of the southern East China Sea: Origin, molecular composition and flux

    Science.gov (United States)

    Chen, You-Xin; Chen, Hung-Yu; Wang, Wei; Yeh, Jun-Xian; Chou, Wen-Chen; Gong, Gwo-Ching; Tsai, Fu-Jung; Huang, Shih-Jen; Lin, Cheng-Ting

    2015-07-01

    In this study, we collected and analyzed rainwater samples from Keelung, Taiwan, which is a coastal city located south of the East China Sea (ECS). From January 2012 until June 2013, 78 rainwater samples were collected over an 18-month period and were analyzed to examine the total dissolved nitrogen (TDN) and major ions in the rainwater. TDN can be divided into dissolved inorganic nitrogen (DIN) and dissolved organic nitrogen (DON). This study, which focused on the composition of DON, is the first study to employ ultrafiltration to separate DON in wet deposition into low molecular weight-DON (LMW-DON) and high molecular weight-DON (HMW-DON). The concentrations of dissolved nitrogen species observed in the research area between November 2012 and April 2013 were relatively high, whereas those observed between May 2013 and October 2012 were relatively low. The patterns of changes over time were similar to those of non-sea-salt (nss) ions. The concentration of nss-ions was high during months in which the total dissolved nitrogen concentration was also high, which occur frequently during the spring and winter. In addition, the concentration of nss-ions was low during months in which the TDN concentration was low, which primarily occurs during the summer. The amounts of DIN and DON accounted for 63 ± 5% and 37 ± 5% of the TDN, respectively, and the percentage of the DIN was higher during the spring and winter. The concentrations of LMW-DON and HMW-DON, which accounted for 84 ± 3% and 16 ± 3% of the DON, respectively, were both high in the winter and low in the summer. The percentage of LMW-DON increased in the summer, possibly because of the numerous oceanic air masses and typhoons. Furthermore, the percentage of HMW-DON increased in the spring, potentially due to biomass burning during agricultural activities. Regarding the wet deposition fluxes, the DIN (197 ± 10.27 mmol m-2 yr-1) and DON (129 ± 6.82 mmol m-2 yr-1) accounted for approximately 64% and 36% of the

  10. Evaluating the effectiveness of pollution control measures via the occurrence of DDTs and HCHs in wet deposition of an urban center, China.

    Science.gov (United States)

    Guo, Ling-Chuan; Bao, Lian-Jun; Li, Shao-Meng; Tao, Shu; Zeng, Eddy Y

    2017-04-01

    Wet deposition is not only a mechanism for removing atmospheric pollutants, but also a process which reflects loadings of atmospheric pollutants. Our previous study on wet deposition examined the effectiveness of short-term control measures on atmospheric particulate pollution, which were partly effective for organic pollutants of current input sources. In the present study, dichlorodiphenyltrichloroethanes (DDTs) and hexachlorocyclohexanes (HCHs), representative of legacy contaminants, were measured in the same samples collected throughout the entire year of 2010 in Guangzhou, a large urban center in South China. Concentrations of ∑DDT (sum of o,p' and p,p'-DDT, o,p' and p,p'-DDE, o,p' and p,p'-DDD, and p,p'-DDMU) and ∑HCH (sum of α-, β-, γ-, and δ-HCH) in wet deposition were in the ranges of nd-69 (average: 1.8 ng L -1 ) and nd-150 ng L -1 (average: 5.1 ng L -1 ), respectively. In addition, the results of source diagnostics and backward air mass trajectories appeared to suggest the transport of antifouling paint derived DDTs from the coastal region off South China to Guangzhou. The combined wet and dry deposition flux of ∑HCH in the first quarter (January to March) was greater than that in the fourth quarter (October to December), while those of ∑DDT were comparable in the first and fourth quarters. Similar trends were also observed for the concentrations of ∑HCH and ∑DDT in aerosol samples. These results suggested the short-term pollution control measures implemented during the 16th Asian Games and 10th Asian Para Games (held in November and December 2010, respectively) did not work well for DDTs. The reduced input of HCHs during the fourth quarter was probably associated with the strict ban on lindane for food safety, which also exposed the weakness of control measures focusing mainly on the removal of atmospheric particulate matter. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Comparative X-ray photoelectron spectroscopy study of plasma enhanced chemical vapor deposition and micro pressure chemical vapor deposition of phosphorus silicate glass layers after rapid thermal annealing

    International Nuclear Information System (INIS)

    Beshkov, G.; Krastev, V.; Gogova, D.; Talik, E.; Adamies, M.

    2008-01-01

    In this paper the bonding state of Phosphorus Silicate Glass (PSG) layers obtained by two different technological approaches, i.e. in two types of reactors: Plasma Enhanced Chemical Vapor Deposition (PECVD) and Micro Pressure Chemical Vapor Deposition (MPCVD) are investigated employing XPS and AES. The PSG layers are deposited at 380 0 C and 420 0 C in corresponding reactors. XPS and AES analyses show that Si2p peak recorded from PECVD layers are not as expected at their position characteristics of silicon dioxide but instead they are at the characteristic of elemental silicon. Plasma enhancement during deposition leads to less oxidized and more inhomogeneous layer. After rapid thermal annealing the Si2p peak is situated at position characteristic of silicon dioxide. (authors)

  12. Breakthrough to Non-Vacuum Deposition of Single-Crystal, Ultra-Thin, Homogeneous Nanoparticle Layers: A Better Alternative to Chemical Bath Deposition and Atomic Layer Deposition

    Directory of Open Access Journals (Sweden)

    Yu-Kuang Liao

    2017-04-01

    Full Text Available Most thin-film techniques require a multiple vacuum process, and cannot produce high-coverage continuous thin films with the thickness of a few nanometers on rough surfaces. We present a new ”paradigm shift” non-vacuum process to deposit high-quality, ultra-thin, single-crystal layers of coalesced sulfide nanoparticles (NPs with controllable thickness down to a few nanometers, based on thermal decomposition. This provides high-coverage, homogeneous thickness, and large-area deposition over a rough surface, with little material loss or liquid chemical waste, and deposition rates of 10 nm/min. This technique can potentially replace conventional thin-film deposition methods, such as atomic layer deposition (ALD and chemical bath deposition (CBD as used by the Cu(In,GaSe2 (CIGS thin-film solar cell industry for decades. We demonstrate 32% improvement of CIGS thin-film solar cell efficiency in comparison to reference devices prepared by conventional CBD deposition method by depositing the ZnS NPs buffer layer using the new process. The new ZnS NPs layer allows reduction of an intrinsic ZnO layer, which can lead to severe shunt leakage in case of a CBD buffer layer. This leads to a 65% relative efficiency increase.

  13. Role of Annealing Temperature on Morphology of Alumina Thin Film Prepared by Wet-Chemical Method

    Directory of Open Access Journals (Sweden)

    Manju Pandey

    2015-03-01

    Full Text Available In this paper, we reported the compositional, morphological and structural properties of the alumina(Al2O3 thin films prepared by sol-gel technique and annealed between 800 0C to 1200 0C for 1-hour in an air atmosphere. The deposited films were polycrystalline in nature. Thin films were found uniform and adherent to the alumina substrate. Effect of annealing temperature on structural parameters such as pore size and surface area were calculated. The result indicates that pore size and surface area was decreased by increasing annealing temperature. The material characterization was done by field emission scanning electron microscope (SEM, atomic force microscopy (AFM and Brunaur, Emmet and Teller (BET.

  14. Influence of annealing temperature on the structural, mechanical and wetting property of TiO2 films deposited by RF magnetron sputtering

    International Nuclear Information System (INIS)

    Pradhan, Swati S.; Sahoo, Sambita; Pradhan, S.K.

    2010-01-01

    TiO 2 films have been deposited on silicon substrates by radio frequency magnetron sputtering of a pure Ti target in Ar/O 2 plasma. The TiO 2 films deposited at room temperature were annealed for 1 h at different temperatures ranging from 400 o C to 800 o C. The structural, morphological, mechanical properties and the wetting behavior of the as deposited and annealed films were obtained using Raman spectroscopy, atomic force microscopy, transmission electron microscopy, nanoindentation and water contact angle (CA) measurements. The as deposited films were amorphous, and the Raman results showed that anatase phase crystallization was initiated at annealing temperature close to 400 o C. The film annealed at 400 o C showed higher hardness than the film annealed at 600 o C. In addition, the wettability of film surface was enhanced with an increase in annealing temperature from 400 o C to 800 o C, as revealed by a decrease in water CA from 87 o to 50 o . Moreover, the water CA of the films obtained before and after UV light irradiation revealed that the annealed films remained more hydrophilic than the as deposited film after irradiation.

  15. Metallization on FDM Parts Using the Chemical Deposition Technique

    Directory of Open Access Journals (Sweden)

    Azhar Equbal

    2014-08-01

    Full Text Available Metallization of ABS (acrylonitrile-butadiene-styrene parts has been studied on flat part surfaces. These parts are fabricated on an FDM (fused deposition modeling machine using the layer-wise deposition principle using ABS as a part material. Electroless copper deposition on ABS parts was performed using two different surface preparation processes, namely ABS parts prepared using chromic acid for etching and ABS parts prepared using a solution mixture of sulphuric acid and hydrogen peroxide (H2SO4/H2O2 for etching. After surface preparations using these routes, copper (Cu is deposited electrolessly using four different acidic baths. The acidic baths used are 5 wt% CuSO4 (copper sulfate with 15 wt% of individual acids, namely HF (hydrofluoric acid, H2SO4 (sulphuric acid, H3PO4 (phosphoric acid and CH3COOH (acetic acid. Cu deposition under different acidic baths used for both the routes is presented and compared based on their electrical performance, scanning electron microscopy (SEM and energy dispersive X-ray spectrometry (EDS. The result shows that chromic acid etched samples show better electrical performance and Cu deposition in comparison to samples etched via H2SO4/H2O2.

  16. Spatial and temporal variability of 7Be and 210Pb wet deposition during four successive monsoon storms in a catchment of northern Laos

    International Nuclear Information System (INIS)

    Gourdin, E.; Evrard, O.; Huon, S.; Reyss, J.-L.; Ribolzi, O.; Bariac, T.; Sengtaheuanghoung, O.; Ayrault, S.

    2014-01-01

    Fallout radionuclides 7 Be and 210 Pb have been identified as potentially relevant temporal tracers for studying soil particles dynamics (surface vs. subsurface sources contribution; remobilization of in-channel sediment) during erosive events in river catchments. An increasing number of studies compared 7 Be: 210 Pb activity ratio in rainwater and sediment to estimate percentages of freshly eroded particles. However, the lack of data regarding the spatial and temporal variability of radionuclide wet deposition during individual storms has been identified as one of the main gaps in these estimates. In order to determine these key parameters, rainwater samples were collected at three stations during four storms that occurred at the beginning of the monsoon (June 2013) in the Houay Xon mountainous catchment in northern Laos. Rainwater 7 Be and 210 Pb activities measured using very low background hyperpure Germanium detectors ranged from 0.05 to 1.72 Bq L −1 and 0.02 to 0.26 Bq L −1 , respectively. Water δ 18 O were determined on the same samples. Total rainfall amount of the four sampled storms ranged from 4.8 to 26.4 mm (51 mm in total) at the time-fractionated collection point. Corresponding cumulative 7 Be and 210 Pb wet depositions during the sampling period were 17.6 and 2.9 Bq m −2 , respectively. The 7 Be: 210 Pb activity ratio varied (1) in space from 6 to 9 for daily deposition and (2) in time from 3 to 12 for samples successively collected. Intra-event evolution of rainwater 7 Be and 210 Pb activities as well as δ 18 O highlighted the progressive depletion of local infra-cloud atmosphere radionuclide stock with time (washout), which remains consistent with a Raleigh-type distillation process for water vapour. Intra-storm ratio increasing with time showed the increasing contribution of rainout scavenging. Implications of such variability for soil particle labelling and erosion studies are briefly discussed and recommendations are formulated for the

  17. Room-temperature plasma-enhanced chemical vapor deposition of SiOCH films using tetraethoxysilane

    International Nuclear Information System (INIS)

    Yamaoka, K.; Yoshizako, Y.; Kato, H.; Tsukiyama, D.; Terai, Y.; Fujiwara, Y.

    2006-01-01

    Carbon-doped silicon oxide (SiOCH) thin films were deposited by room-temperature plasma-enhanced chemical vapor deposition (PECVD) using tetraethoxysilane (TEOS). The deposition rate and composition of the films strongly depended on radio frequency (RF) power. The films deposited at low RF power contained more CH n groups. The SiOCH films showed high etch rate and low refractive index in proportion to the carbon composition. The deposition with low plasma density and low substrate temperature is effective for SiOCH growth by PECVD using TEOS

  18. Laser chemical vapor deposition of millimeter scale three-dimensional shapes

    Science.gov (United States)

    Shaarawi, Mohammed Saad

    2001-07-01

    Laser chemical vapor deposition (LCVD) has been successfully developed as a technique to synthesize millimeter-scale components directly from the gas phase. Material deposition occurs when heat generated by the interaction of a laser beam with a substrate thermally decomposes the gas precursor. Selective illumination or scanning the laser beam over portions of a substrate forms the single thin layer of material that is the building block of this process. Sequential scanning of the laser in a pre-defined pattern on the substrate and subsequent deposit causes the layers to accumulate forming the three-dimensional shape. The primary challenge encountered in LCVD shape forming is the synthesis of uniform layers. Three deposition techniques are studied to address this problem. The most successful technique, Active Surface Deposition, is based on the premise that the most uniform deposits are created by measuring the deposition surface topology and actively varying the deposition rate in response to features at the deposition surface. Defects observed in the other techniques were significantly reduced or completely eliminated using Active Surface Deposition. The second technique, Constant Temperature Deposition, maintains deposit uniformity through the use of closed-loop modulation of the laser power to sustain a constant surface temperature during deposition. The technique was successful in depositing high quality graphite tubes >2 mm tall from an acetylene precursor and partially successful in depositing SiC + C composite tubes from tetramethylsilane (TMS). The final technique, Constant Power Deposition, is based on the premise that maintaining a uniform power output throughout deposition would result in the formation of uniform layers. Constant Power Deposition failed to form coherent shapes. Additionally, LCVD is studied using a combination of analytic and numerical models to gain insight into the deposition process. Thermodynamic modeling is used to predict the

  19. Thermodynamic calculations for chemical vapor deposition of silicon carbide

    International Nuclear Information System (INIS)

    Minato, Kazuo; Fukuda, Kousaku; Ikawa, Katsuichi

    1985-03-01

    The composition of vapor and condensed phases at equilibrium and CVD phase diagrams were calculated for the CH 3 SiCl 3 -H 2 -Ar system using a computer code SOLGASMIX-PV, which is based on the free energy minimization method. These calculations showed that β-SiC, β-SiC+C(s), β-SiC+Si(s), β-SiC+Si(l), Si(s), Si(l), or C(s) would be deposited depending on deposition parameters. In the CH 3 SiCl 3 -Ar system, condensed phase was found to be β-SiC+C(s) or C(s). Comparing the calculated CVD phase diagrams with the experimental results from the literature, β-SiC+C(s) and β-SiC+Si(s) were deposited in the experiments at the high temperature (more than 2000K) and low temperature (less than 1700K) parts of a resion, respectively, where only β-SiC would be deposited in the calculations. These are remakable results to consider the deposition mechanism of silicon carbide. (author)

  20. Technical Note: Quantification of interferences of wet chemical HONO LOPAP measurements under simulated polar conditions

    Directory of Open Access Journals (Sweden)

    J. Kleffmann

    2008-11-01

    Full Text Available In the present pilot study, an optimized LOPAP instrument (LOng Path Absorption Photometer for the detection of nitrous acid (HONO in the atmosphere (DL 0.2 pptV was tested at the high alpine research station Jungfraujoch at 3580 m altitude in the Swiss Alps under conditions comparable to polar regions. HONO concentrations in the range <0.5–50 pptV with an average of 7.5 pptV were observed at the Jungfraujoch. The diurnal profiles obtained exhibited clear maxima at noon and minima with very low concentration during the night supporting the proposed photochemical production of HONO. In good agreement with recent measurements at the South Pole, it was demonstrated, that interferences of chemical HONO instruments can significantly influence the measurements and lead to considerable overestimations, especially for low pollution level. Accordingly, the active correction of interferences is of paramount importance for the determination of reliable HONO data.

  1. Controlled low-temperature fabrication of ZnO nanopillars with a wet-chemical approach

    Energy Technology Data Exchange (ETDEWEB)

    Postels, B [Institute of Semiconductor Technology, Technical University of Braunschweig, Hans-Sommer-Strasse 66, D-38106 Braunschweig (Germany); Wehmann, H-H [Institute of Semiconductor Technology, Technical University of Braunschweig, Hans-Sommer-Strasse 66, D-38106 Braunschweig (Germany); Bakin, A [Institute of Semiconductor Technology, Technical University of Braunschweig, Hans-Sommer-Strasse 66, D-38106 Braunschweig (Germany); Kreye, M [Institute of Semiconductor Technology, Technical University of Braunschweig, Hans-Sommer-Strasse 66, D-38106 Braunschweig (Germany); Fuhrmann, D [Institute of Applied Physics, Technical University of Braunschweig, Mendelssohnstrasse 2, D-38106 Braunschweig (Germany); Blaesing, J [Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg, Universitaetsplatz 1, 39016 Magdeburg (Germany); Hangleiter, A [Institute of Applied Physics, Technical University of Braunschweig, Mendelssohnstrasse 2, D-38106 Braunschweig (Germany); Krost, A [Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg, Universitaetsplatz 1, 39016 Magdeburg (Germany); Waag, A [Institute of Semiconductor Technology, Technical University of Braunschweig, Hans-Sommer-Strasse 66, D-38106 Braunschweig (Germany)

    2007-05-16

    Aqueous chemical growth (ACG) is an efficient way to generate wafer-scale and densely packed arrays of ZnO nanopillars on various substrate materials. ACG is a low-temperature growth approach that is only weakly influenced by the substrate and even allows growth on flexible polymer substrates or on conducting materials. The advanced fabrication of wafer-scale and highly vertically aligned arrays of ZnO nanopillars on various substrate materials is demonstrated. Moreover, it is possible to control the morphology in diameter and length by changing the growth conditions. Photoluminescence characterization clearly shows a comparatively strong band-edge luminescence, even at room temperature, that is accompanied by a rather weak visible luminescence in the yellow/orange spectral range.

  2. Process for the preparation of fiber-reinforced ceramic composites by chemical vapor deposition

    Science.gov (United States)

    Lackey, Jr., Walter J.; Caputo, Anthony J.

    1986-01-01

    A chemical vapor deposition (CVD) process for preparing fiber-reinforced ceramic composites. A specially designed apparatus provides a steep thermal gradient across the thickness of a fibrous preform. A flow of gaseous ceramic matrix material is directed into the fibrous preform at the cold surface. The deposition of the matrix occurs progressively from the hot surface of the fibrous preform toward the cold surface. Such deposition prevents the surface of the fibrous preform from becoming plugged. As a result thereof, the flow of reactant matrix gases into the uninfiltrated (undeposited) portion of the fibrous preform occurs throughout the deposition process. The progressive and continuous deposition of ceramic matrix within the fibrous preform provides for a significant reduction in process time over known chemical vapor deposition processes.

  3. Chemical vapor deposition based tungsten disulfide (WS2) thin film transistor

    KAUST Repository

    Hussain, Aftab M.; Sevilla, Galo T.; Rader, Kelly; Hussain, Muhammad Mustafa

    2013-01-01

    electric field. This makes them an interesting option for channel material in field effect transistors (FETs). Therefore, we show a highly manufacturable chemical vapor deposition (CVD) based simple process to grow WS2 directly on silicon oxide in a furnace

  4. Continuous, Highly Flexible, and Transparent Graphene Films by Chemical Vapor Deposition for Organic Photovoltaics

    KAUST Repository

    Gomez De Arco, Lewis; Zhang, Yi; Schlenker, Cody W.; Ryu, Koungmin; Thompson, Mark E.; Zhou, Chongwu

    2010-01-01

    We report the implementation of continuous, highly flexible, and transparent graphene films obtained by chemical vapor deposition (CVD) as transparent conductive electrodes (TCE) in organic photovoltaic cells. Graphene films were synthesized by CVD

  5. Rapid Thermal Chemical Vapor Deposition for Dual-Gated Sub-100 nm MOSFET's

    National Research Council Canada - National Science Library

    Sturm, James

    2001-01-01

    ... (such as microprocessors and memory chips) is based. This project examines the scaling of MOSFET's to very small channel dimensions using a vertical structure which is defined by Rapid Thermal Chemical Vapor Deposition...

  6. A kinetic and equilibrium analysis of silicon carbide chemical vapor deposition on monofilaments

    Science.gov (United States)

    Gokoglu, S. A.; Kuczmarski, M. A.

    1993-01-01

    Chemical kinetics of atmospheric pressure silicon carbide (SiC) chemical vapor deposition (CVD) from dilute silane and propane source gases in hydrogen is numerically analyzed in a cylindrical upflow reactor designed for CVD on monofilaments. The chemical composition of the SiC deposit is assessed both from the calculated total fluxes of carbon and silicon and from chemical equilibrium considerations for the prevailing temperatures and species concentrations at and along the filament surface. The effects of gas and surface chemistry on the evolution of major gas phase species are considered in the analysis.

  7. Size- and Shape-Dependent Antibacterial Studies of Silver Nanoparticles Synthesized by Wet Chemical Routes

    Directory of Open Access Journals (Sweden)

    Muhammad Akram Raza

    2016-04-01

    Full Text Available Silver nanoparticles (AgNPs of different shapes and sizes were prepared by solution-based chemical reduction routes. Silver nitrate was used as a precursor, tri-sodium citrate (TSC and sodium borohydride as reducing agents, while polyvinylpyrrolidone (PVP was used as a stabilizing agent. The morphology, size, and structural properties of obtained nanoparticles were characterized by scanning electron microscopy (SEM, UV-visible spectroscopy (UV-VIS, and X-ray diffraction (XRD techniques. Spherical AgNPs, as depicted by SEM, were found to have diameters in the range of 15 to 90 nm while lengths of the edges of the triangular particles were about 150 nm. The characteristic surface plasmon resonance (SPR peaks of different spherical silver colloids occurring in the wavelength range of 397 to 504 nm, whereas triangular particles showed two peaks, first at 392 nm and second at 789 nm as measured by UV-VIS. The XRD spectra of the prepared samples indicated the face-centered cubic crystalline structure of metallic AgNPs. The in vitro antibacterial properties of all synthesized AgNPs against two types of Gram-negative bacteria, Pseudomonas aeruginosa and Escherichia coli were examined by Kirby–Bauer disk diffusion susceptibility method. It was noticed that the smallest-sized spherical AgNPs demonstrated a better antibacterial activity against both bacterial strains as compared to the triangular and larger spherical shaped AgNPs.

  8. Expanding thermal plasma chemical vapour deposition of ZnO:Al layers for CIGS solar cells

    NARCIS (Netherlands)

    Sharma, K.; Williams, B.L.; Mittal, A.; Knoops, H.C.M.; Kniknie, B.J.; Bakker, N.J.; Kessels, W.M.M.; Schropp, R.E.I.; Creatore, M.

    2014-01-01

    Aluminium-doped zinc oxide (ZnO:Al) grown by expanding thermal plasma chemical vapour deposition (ETP-CVD) has demonstrated excellent electrical and optical properties, which make it an attractive candidate as a transparent conductive oxide for photovoltaic applications. However, when depositing

  9. Metal–organic covalent network chemical vapor deposition for gas separation

    NARCIS (Netherlands)

    Boscher, N.D.; Wang, M.; Perrotta, A.; Heinze, K.; Creatore, A.; Gleason, K.K.

    2016-01-01

    The chemical vapor deposition (CVD) polymerization of metalloporphyrin building units is demonstrated to provide an easily up-scalable one-step method toward the deposition of a new class of dense and defect-free metal–organic covalent network (MOCN) layers. The resulting hyper-thin and flexible

  10. Physical and chemical properties of deposited airborne particulates over the Arabian Red Sea coastal plain

    KAUST Repository

    Engelbrecht, Johann; Stenchikov, Georgiy L.; Prakash, P. Jish; Lersch, Traci; Anisimov, Anatolii; Shevchenko, Illia

    2017-01-01

    ) situated on the Red Sea coastal plain of Saudi Arabia and subjected to the same chemical and mineralogical analysis we conducted on soil samples. Frisbee deposition samplers with foam inserts were used to collect dust and other deposits, for the period

  11. Plasma-enhanced chemical vapor deposition of aluminum oxide using ultrashort precursor injection pulses

    NARCIS (Netherlands)

    Dingemans, G.; Sanden, van de M.C.M.; Kessels, W.M.M.

    2012-01-01

    An alternative plasma-enhanced chemical vapor deposition (PECVD) method is developed and applied for the deposition of high-quality aluminum oxide (AlOx) films. The PECVD method combines a continuous plasma with ultrashort precursor injection pulses. We demonstrate that the modulation of the

  12. Plasma enhanced chemical vapor deposition silicon oxynitride optimized for application in integrated optics

    NARCIS (Netherlands)

    Worhoff, Kerstin; Driessen, A.; Lambeck, Paul; Hilderink, L.T.H.; Linders, Petrus W.C.; Popma, T.J.A.

    1999-01-01

    Silicon Oxynitride layers are grown from SiH4/N2, NH3 and N2O by Plasma Enhanced Chemical Vapor Deposition. The process is optimized with respect to deposition of layers with excellent uniformity in the layer thickness, high homogeneity of the refractive index and good reproducibility of the layer

  13. Dry transfer of chemical-vapor-deposition-grown graphene onto liquid-sensitive surfaces for tunnel junction applications

    International Nuclear Information System (INIS)

    Feng, Ying; Chen, Ke

    2015-01-01

    We report a dry transfer method that can tranfer chemical vapor deposition (CVD) grown graphene onto liquid-sensitive surfaces. The graphene grown on copper (Cu) foil substrate was first transferred onto a freestanding 4 μm thick sputtered Cu film using the conventional wet transfer process, followed by a dry transfer process onto the target surface using a polydimethylsiloxane stamp. The dry-transferred graphene has similar properties to traditional wet-transferred graphene, characterized by scanning electron microscopy, atomic force microscopy, Raman spectroscopy, and electrical transport measurements. It has a sheet resistance of 1.6 ∼ 3.4 kΩ/□, hole density of (4.1 ∼ 5.3) × 10 12 cm −2 , and hole mobility of 460 ∼ 760 cm 2 V −1 s −1 without doping at room temperature. The results suggest that large-scale CVD-grown graphene can be transferred with good quality and without contaminating the target surface by any liquid. Mg/MgO/graphene tunnel junctions were fabricated using this transfer method. The junctions show good tunneling characteristics, which demonstrates the transfer technique can also be used to fabricate graphene devices on liquid-sensitive surfaces. (paper)

  14. Extended phase homogeneity and electrical properties of barium calcium titanate prepared by the wet chemical methods

    International Nuclear Information System (INIS)

    Jayanthi, S.; Kutty, T.R.N.

    2004-01-01

    Ca-substituted BaTiO 3 with extended homogeneity range upto ∼50 mol% CaTiO 3 have been prepared by three different chemical routes namely carbonate-oxalate (COBCT), gel-carbonate (GCBCT), and gel-to-crystallite conversion (GHBCT) followed by heat treatment above 1150 deg. C. X-ray powder diffraction (XRD) data show continuous decrease in the tetragonal unit cell parameters as well as c 0 /a 0 ratio with CaTiO 3 content, which are in accordance with the substitution of smaller sized Ca 2+ ions at the barium sites. The microstructure as well as the dielectric properties are greatly influenced by the cationic ratio, α=(Ba+Ca)/Ti. The grain size decreases with CaTiO 3 content for the stoichiometric samples (α=1), whereas ultrafine microstructure is observed in the case of off-stoichiometric samples (α>1) for the whole compositional range of CaTiO 3 concentrations. Sharper ε r -T characteristics at lower calcium content and broader ε r -T with decreased ε max , in the higher calcium range are observed in the case of α=1. Whereas nanometer grained ceramics exhibiting diffuse ε r -T characteristics are obtained in the case of α>1. The positive temperature coefficient of resistivity (PTCR) is realized for barium calcium titanate ceramics having 0.3 at.% Sb as the donor dopant for higher CaTiO 3 (typically 30 mol%) containing samples (α=1), indicating that Ca 2+ ions do not behave as acceptors if they were to substitute at the Ti 4+ sites. Whereas the off-stoichiometric (α>1) ceramics retained high resistivity, indicative of the Ti-site occupancy for Ca 2+ in fine grain ceramics

  15. Modeling dry and wet deposition of sulfate, nitrate, and ammonium ions in Jiuzhaigou National Nature Reserve, China using a source-oriented CMAQ model: Part II. Emission sector and source region contributions.

    Science.gov (United States)

    Qiao, Xue; Tang, Ya; Kota, Sri Harsha; Li, Jingyi; Wu, Li; Hu, Jianlin; Zhang, Hongliang; Ying, Qi

    2015-11-01

    A source-oriented Community Multiscale Air Quality (CMAQ) model driven by the meteorological fields generated by the Weather Research and Forecasting (WRF) model was used to study the dry and wet deposition of nitrate (NO3(-)), sulfate (SO4(2-)), and ammonium (NH4(+)) ions in the Jiuzhaigou National Nature Reserve (JNNR), China from June to August 2010 and to identify the contributions of different emission sectors and source regions that were responsible for the deposition fluxes. Contributions from power plants, industry, transportation, domestic, biogenic, windblown dust, open burning, fertilizer, and manure management sources to deposition fluxes in JNNR watershed and four EANET sites are determined. In JNNR, 96%, 82%, and 87% of the SO4(2-), NO3(-) and NH4(+) deposition fluxes are in the form of wet deposition of the corresponding aerosol species. Industry and power plants are the two major sources of SO4(2-) deposition flux, accounting for 86% of the total wet deposition of SO4(2-), and industry has a higher contribution (56%) than that of power plants (30%). Power plants and industry are also the top sources that are responsible for NO3(-) wet deposition, and contributions from power plants (30%) are generally higher than those from industries (21%). The major sources of NH4(+) wet deposition flux in JNNR are fertilizer (48%) and manure management (39%). Source-region apportionment confirms that SO2 and NOx emissions from local and two nearest counties do not have a significant impact on predicted wet deposition fluxes in JNNR, with contributions less than 10%. While local NH3 emissions account for a higher fraction of the NH4(+) deposition, approximately 70% of NH4(+) wet deposition in JNNR originated from other source regions. This study demonstrates that S and N deposition in JNNR is mostly from long-range transport rather than from local emissions, and to protect JNNR, regional emission reduction controls are needed. Copyright © 2015 Elsevier B.V. All

  16. Photocatalytic activity of tin-doped TiO{sub 2} film deposited via aerosol assisted chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Chua, Chin Sheng, E-mail: cschua@simtech.a-star.edu.sg [School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore); Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, 638075 (Singapore); Tan, Ooi Kiang; Tse, Man Siu [School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore); Ding, Xingzhao [Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, 638075 (Singapore)

    2013-10-01

    Tin-doped TiO{sub 2} films are deposited via aerosol assisted chemical vapor deposition using a precursor mixture composing of titanium tetraisopropoxide and tetrabutyl tin. The amount of tin doping in the deposited films is controlled by the volume % concentration ratio of tetrabutyl tin over titanium tetraisopropoxide in the mixed precursor solution. X-ray diffraction analysis results reveal that the as-deposited films are composed of pure anatase TiO{sub 2} phase. Red-shift in the absorbance spectra is observed attributed to the introduction of Sn{sup 4+} band states below the conduction band of TiO{sub 2}. The effect of tin doping on the photocatalytic property of TiO{sub 2} films is studied through the degradation of stearic acid under UV light illumination. It is found that there is a 10% enhancement on the degradation rate of stearic acid for the film with 3.8% tin doping in comparison with pure TiO{sub 2} film. This improvement of photocatalytic performance with tin incorporation could be ascribed to the reduction of electron-hole recombination rate through charge separation and an increased amount of OH radicals which are crucial for the degradation of stearic acid. Further increase in tin doping results in the formation of recombination site and large anatase grains, which leads to a decrease in the degradation rate. - Highlights: ► Deposition of tin-doped TiO{sub 2} film via aerosol assisted chemical vapor depositionDeposited anatase films show red-shifted in UV–vis spectrum with tin-dopants. ► Photoactivity improves at low tin concentration but reduces at higher concentration. ► Improvement in photoactivity due to bandgap narrowing from Sn{sup 4+} band states ► Maximum photoactivity achieved occurs for films with 3.8% tin doping.

  17. Chemical vapor deposition polymerization the growth and properties of parylene thin films

    CERN Document Server

    Fortin, Jeffrey B

    2004-01-01

    Chemical Vapor Deposition Polymerization - The Growth and Properties of Parylene Thin Films is intended to be valuable to both users and researchers of parylene thin films. It should be particularly useful for those setting up and characterizing their first research deposition system. It provides a good picture of the deposition process and equipment, as well as information on system-to-system variations that is important to consider when designing a deposition system or making modifications to an existing one. Also included are methods to characterizae a deposition system's pumping properties as well as monitor the deposition process via mass spectrometry. There are many references that will lead the reader to further information on the topic being discussed. This text should serve as a useful reference source and handbook for scientists and engineers interested in depositing high quality parylene thin films.

  18. Chemical vapor deposition of Si/SiC nano-multilayer thin films

    International Nuclear Information System (INIS)

    Weber, A.; Remfort, R.; Woehrl, N.; Assenmacher, W.; Schulz, S.

    2015-01-01

    Stoichiometric SiC films were deposited with the commercially available single source precursor Et_3SiH by classical thermal chemical vapor deposition (CVD) as well as plasma-enhanced CVD at low temperatures in the absence of any other reactive gases. Temperature-variable deposition studies revealed that polycrystalline films containing different SiC polytypes with a Si to carbon ratio of close to 1:1 are formed at 1000 °C in thermal CVD process and below 100 °C in the plasma-enhanced CVD process. The plasma enhanced CVD process enables the reduction of residual stress in the deposited films and offers the deposition on temperature sensitive substrates in the future. In both deposition processes the film thickness can be controlled by variation of the process parameters such as the substrate temperature and the deposition time. The resulting material films were characterized with respect to their chemical composition and their crystallinity using scanning electron microscope, energy dispersive X-ray spectroscopy (XRD), atomic force microscopy, X-ray diffraction, grazing incidence X-ray diffraction, secondary ion mass spectrometry and Raman spectroscopy. Finally, Si/SiC multilayers of up to 10 individual layers of equal thickness (about 450 nm) were deposited at 1000 °C using Et_3SiH and SiH_4. The resulting multilayers features amorphous SiC films alternating with Si films, which feature larger crystals up to 300 nm size as measured by transmission electron microscopy as well as by XRD. XRD features three distinct peaks for Si(111), Si(220) and Si(311). - Highlights: • Stoichiometric silicon carbide films were deposited from a single source precursor. • Thermal as well as plasma-enhanced chemical vapor deposition was used. • Films morphology, crystallinity and chemical composition were characterized. • Silicon/silicon carbide multilayers of up to 10 individual nano-layers were deposited.

  19. A simple method to deposit palladium doped SnO2 thin films using plasma enhanced chemical vapor deposition technique

    International Nuclear Information System (INIS)

    Kim, Young Soon; Wahab, Rizwan; Shin, Hyung-Shik; Ansari, S. G.; Ansari, Z. A.

    2010-01-01

    This work presents a simple method to deposit palladium doped tin oxide (SnO 2 ) thin films using modified plasma enhanced chemical vapor deposition as a function of deposition temperature at a radio frequency plasma power of 150 W. Stannic chloride (SnCl 4 ) was used as precursor and oxygen (O 2 , 100 SCCM) (SCCM denotes cubic centimeter per minute at STP) as reactant gas. Palladium hexafluroacetyleacetonate (Pd(C 5 HF 6 O 2 ) 2 ) was used as a precursor for palladium. Fine granular morphology was observed with tetragonal rutile structure. A peak related to Pd 2 Sn is observed, whose intensity increases slightly with deposition temperature. Electrical resistivity value decreased from 8.6 to 0.9 mΩ cm as a function of deposition temperature from 400 to 600 deg. C. Photoelectron peaks related to Sn 3d, Sn 3p3, Sn 4d, O 1s, and C 1s were detected with varying intensities as a function of deposition temperature.

  20. Effects of deposition period on the chemical bath deposited Cu4SnS4 thin films

    International Nuclear Information System (INIS)

    Kassim, Anuar; Wee Tee, Tan; Soon Min, Ho.; Nagalingam, Saravanan

    2010-01-01

    Cu 4 SnS 4 thin films were prepared by simple chemical bath deposition technique. The influence of deposition period on the structural, morphological and optical properties of films was studied. The films were characterized using X-ray diffraction, atomic force microscopy and UV-Vis Spectrophotometer. X-ray diffraction patterns indicated that the films were polycrystalline with prominent peak attributed to (221) plane of orthorhombic crystal structure. The films prepared at 80 min showed significant increased in the intensity of all diffractions. According to AFM images, these films indicated that the surface of substrate was covered completely. The obtained films also produced higher absorption characteristics when compared to the films prepared at other deposition periods based on optical absorption studies. The band gap values of films deposited at different deposition periods were in the range of 1.6-2.1 eV. Deposition for 80 min was found to be the optimum condition to produce good quality thin films under the current conditions. (author).

  1. Mechanisms and rates of atmospheric deposition of selected trace elements and sulfate to a deciduous forest watershed. [Roles of dry and wet deposition concentrations measured in Walker Branch Watershed

    Energy Technology Data Exchange (ETDEWEB)

    Lindberg, S.E.; Harriss, R.C.; Turner, R.R.; Shriner, D.S.; Huff, D.D.

    1979-06-01

    The critical links between anthropogenic emissions to the atmosphere and their effects on ecosystems are the mechanisms and rates of atmospheric deposition. The atmospheric input of several trace elements and sulfate to a deciduous forest canopy is quantified and the major mechanisms of deposition are determined. The study area was Walker Branch Watershed (WBW) in eastern Tennessee. The presence of a significant quantity of fly ash and dispersed soil particles on upward-facing leaf and flat surfaces suggested sedimentation to be a major mechanism of dry deposition to upper canopy elements. The agreement for deposition rates measured to inert, flat surfaces and to leaves was good for Cd, SO/sub 4//sup =/, Zn, and Mn but poor for Pb. The precipitation concentrations of H/sup +/, Pb, Mn, and SO/sub 4//sup =/ reached maximum values during the summer months. About 90% of the wet deposition of Pb and SO/sub 4//sup =/ was attributed to scavenging by in-cloud processes while for Cd and Mn, removal by in-cloud scavenging accounted for 60 to 70% of the deposition. The interception of incoming rain by the forest canopy resulted in a net increase in the concentrations of Cd, Mn, Pb, Zn, and SO/sub 4//sup =/ but a net decrease in the concentration of H/sup +/. The source of these elements in the forest canopy was primarily dry deposited aerosols for Pb, primarily internal plant leaching for Mn, Cd, and Zn, and an approximately equal combination of the two for SO/sub 4//sup =/. Significant fractions of the total annual elemental flux to the forest floor in a representative chestnut oak stand were attributable to external sources for Pb (99%), Zn (44%), Cd (42%), SO/sub 4//sup =/ (39%), and Mn (14%), the remainder being related to internal element cycling mechanisms. On an annual scale the dry deposition process constituted a significant fraction of the total atmospheric input. (ERB)

  2. Reduced chemical warfare agent sorption in polyurethane-painted surfaces via plasma-enhanced chemical vapor deposition of perfluoroalkanes.

    Science.gov (United States)

    Gordon, Wesley O; Peterson, Gregory W; Durke, Erin M

    2015-04-01

    Perfluoralkalation via plasma chemical vapor deposition has been used to improve hydrophobicity of surfaces. We have investigated this technique to improve the resistance of commercial polyurethane coatings to chemicals, such as chemical warfare agents. The reported results indicate the surface treatment minimizes the spread of agent droplets and the sorption of agent into the coating. The improvement in resistance is likely due to reduction of the coating's surface free energy via fluorine incorporation, but may also have contributing effects from surface morphology changes. The data indicates that plasma-based surface modifications may have utility in improving chemical resistance of commercial coatings.

  3. A study of wet deposition of atmospheric tritium releases at the Ontario Power Generation, Pickering Nuclear Generating Station

    International Nuclear Information System (INIS)

    Crooks, G.; DeWilde, J.; Yu, L.

    2001-01-01

    The Ontario Power Generation,Pickering Nuclear Generating Station (PNGS) has been investigating deposition of atmospheric releases of tritium on their site. This study has included numerical dispersion modelling studies conducted over the past three years, as well as an ongoing field monitoring study. The following paper will present results of the field monitoring study and make comparisons to the numerical modelling. The results of this study could be of potential use to nuclear stations in quantifying tritium deposition in near field regions where building wake effects dominate pollutant dispersion

  4. Kinetic Study of the Chemical Vapor Deposition of Tantalum in Long Narrow Channels

    DEFF Research Database (Denmark)

    Mugabi, James Atwoki; Eriksen, Søren; Petrushina, Irina

    2016-01-01

    A kinetic study of the chemical vapor deposition of tantalum in long narrow channels is done to optimize the industrial process for the manufacture of tantalum coated plate heat exchangers. The developed model fits well at temperatures between 750 and 850 °C, and in the pressure range of25–990 mbar....... According to the model, the predominant tantalum growth species is TaCl3. The temperature is shown to have a pronounced effect onthe morphology and rate of deposition of the tantalum and an apparent change in deposition mechanism occurs between 850–900 °C, resulting in the deposition rate at 900 °C being...

  5. Rapid synthesis of tantalum oxide dielectric films by microwave microwave-assisted atmospheric chemical vapor deposition

    International Nuclear Information System (INIS)

    Ndiege, Nicholas; Subramanian, Vaidyanathan; Shannon, Mark A.; Masel, Richard I.

    2008-01-01

    Microwave-assisted chemical vapor deposition has been used to generate high quality, high-k dielectric films on silicon at high deposition rates with film thicknesses varying from 50 nm to 110 μm using inexpensive equipment. Characterization of the post deposition products was performed by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Auger electron spectroscopy and Raman spectroscopy. Film growth was determined to occur via rapid formation and accumulation of tantalum oxide clusters from tantalum (v) ethoxide (Ta(OC 2 H 5 ) 5 ) vapor on the deposition surface

  6. PREPARATION AND CHARACTERIZATION OF IRON SULPHIDE THIN FILMS BY CHEMICAL BATH DEPOSITION METHOD

    Directory of Open Access Journals (Sweden)

    Anuar Kassim

    2010-06-01

    Full Text Available FeS2 thin films have been deposited by using low cost chemical bath deposition technique. The films obtained under deposition parameters such as bath temperature (90 °C, deposition period (90 min, electrolyte concentration (0.15 M and pH of the reactive mixture (pH 2.5. The thin films were characterized using X-ray diffraction and atomic force microscopy in order to study the structural and morphological properties. The band gap energy, transition type and absorption properties were determined using UV-Vis Spectrophotometer. X-ray diffraction displayed a pattern consistent with the formation of an orthorhombic structure, with a strong (110 preferred orientation. Atomic force microscopy image showed the substrate surface is well covered with irregular grains. A direct band gap of 1.85 eV was obtained according to optical absorption studies.   Keywords: Iron sulfide, X-ray diffraction, chemical bath deposition, thin films

  7. A comparative chemical network study of HWCVD deposited amorphous silicon and carbon based alloys thin films

    Energy Technology Data Exchange (ETDEWEB)

    Swain, Bibhu P., E-mail: bibhuprasad.swain@gmail.com [Centre for Materials Science and Nanotechnology, Sikkim Manipal Institute of Technology, Majitar, Rangpo Sikkim (India); Swain, Bhabani S.; Hwang, Nong M. [Thin Films and Microstructure Laboratory, Department of Materials Science and Engineering, Seoul National University, Seoul (Korea, Republic of)

    2014-03-05

    Highlights: • a-SiC:H, a-SiN:H, a-C:H and a-SiCN:H films were deposited by hot wire chemical vapor deposition. • Evolution of microstructure of a-SiCN:H films deposited at different NH{sub 3} flow rate were analyzed. • The chemical network of Si and C based alloys were studied by FTIR and Raman spectroscopy. -- Abstract: Silicon and carbon based alloys were deposited by hot wire chemical vapor deposition (HWCVD). The microstructure and chemical bonding of these films were characterized by field emission scanning electron microscopy, Fourier transform infrared spectroscopy and Raman spectroscopy. The electron microscopy revealed various microstructures were observed for a-C:H, a-SiC:H, a-SiN:H, a-CN:H and a-SiCN:H films. The microstructure of SiN:H films showed agglomerate spherical grains while a-C:H films showed more fractal surface with branched microstructure. However, a-SiC:H, a-CN:H and a-SiCN:H indicated uniform but intermediate surface fractal microstructure. A series of a-SiCN:H films were deposited with variation of NH{sub 3} flow rate. The nitrogen incorporation in a-SiCN:H films alter the carbon network from sp{sup 2} to sp{sup 3} bonding The detail chemical bonding of amorphous films was analyzed by curve fitting method.

  8. Modification of optical and electrical properties of chemical bath deposited CdS using plasma treatments

    International Nuclear Information System (INIS)

    Gonzalez, G.; Krishnan, B.; Avellaneda, D.; Castillo, G. Alan; Das Roy, T.K.; Shaji, S.

    2011-01-01

    Cadmium sulphide (CdS) is a well known n-type semiconductor that is widely used in solar cells. Here we report preparation and characterization of chemical bath deposited CdS thin films and modification of their optical and electrical properties using plasma treatments. CdS thin films were prepared from a chemical bath containing Cadmium chloride, Triethanolamine and Thiourea under various deposition conditions. Good quality thin films were obtained during deposition times of 5, 10 and 15 min. CdS thin films prepared for 10 min. were treated using a glow discharge plasma having nitrogen and argon carrier gases. The changes in morphology, optical and electrical properties of these plasma treated CdS thin films were analyzed in detail. The results obtained show that plasma treatment is an effective technique in modification of the optical and electrical properties of chemical bath deposited CdS thin films.

  9. PbS Thin Films for Photovoltaic Applications Obtained by Non-Traditional Chemical Bath Deposition

    Directory of Open Access Journals (Sweden)

    Pérez-García Claudia Elena

    2015-01-01

    Full Text Available To optimize cost-efficiency relation for thin film solar cells, we explore the recently developed versions of chemical deposition of semiconductor films, together with classic CBD (Chemical Bath Deposition: SILAR (Successive Ionic Layer Adsorption and Reaction and PCBD (Photo Chemical Bath Deposition, all of them ammonia-free and ecologically friendly. The films of CdS and PbS were made, and experimental solar cells with CdS window layer and PbS absorber elaborated. We found that band gap of PbS films can be monitored by deposition process due to porosity-induced quantum confinement which depends on the parameters of the process. We expect that the techniques employed can be successfully used for production of optoelectronic devices.

  10. Modification of optical and electrical properties of chemical bath deposited CdS using plasma treatments

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, G. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon, C.P 66450 (Mexico); Krishnan, B. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon, C.P 66450 (Mexico); CIIDIT, Universidad Autonoma de Nuevo Leon, Apodaca, Nuevo Leon (Mexico); Avellaneda, D.; Castillo, G. Alan; Das Roy, T.K. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon, C.P 66450 (Mexico); Shaji, S., E-mail: sshajis@yahoo.com [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon, C.P 66450 (Mexico); CIIDIT, Universidad Autonoma de Nuevo Leon, Apodaca, Nuevo Leon (Mexico)

    2011-08-31

    Cadmium sulphide (CdS) is a well known n-type semiconductor that is widely used in solar cells. Here we report preparation and characterization of chemical bath deposited CdS thin films and modification of their optical and electrical properties using plasma treatments. CdS thin films were prepared from a chemical bath containing Cadmium chloride, Triethanolamine and Thiourea under various deposition conditions. Good quality thin films were obtained during deposition times of 5, 10 and 15 min. CdS thin films prepared for 10 min. were treated using a glow discharge plasma having nitrogen and argon carrier gases. The changes in morphology, optical and electrical properties of these plasma treated CdS thin films were analyzed in detail. The results obtained show that plasma treatment is an effective technique in modification of the optical and electrical properties of chemical bath deposited CdS thin films.

  11. An in-situ chemical reaction deposition of nanosized wurtzite CdS thin films

    International Nuclear Information System (INIS)

    Chu Juan; Jin Zhengguo; Cai Shu; Yang Jingxia; Hong Zhanglian

    2012-01-01

    Nanocrystalline CdS thin films were deposited on glass substrates by an ammonia-free in-situ chemical reaction synthesis technique using cadmium cationic precursor solid films as reaction source and sodium sulfide based solutions as anionic reaction medium. Effects of ethanolamine addition to the cadmium cationic precursor solid films, deposition cycle numbers and annealing treatments in Ar atmosphere on structure, morphology, chemical composition and optical properties of the resultant films were investigated by X-ray diffraction, field emission scanning electron microscope, energy dispersive X-ray analysis and UV–Vis spectra measurements. The results show that CdS thin films deposited by the in-situ chemical reaction synthesis have wurtzite structure with (002) plane preferential orientation and crystallite size is in the range of 16 nm–19 nm. The growth of film thickness is almost constant with deposition cycle numbers and about 96 nm per cycle.

  12. Ammonia-free chemical bath method for deposition of microcrystalline cadmium selenide films

    International Nuclear Information System (INIS)

    Lokhande, C.D.; Lee, Eun-Ho; Jung, Kwang-Deog; Joo, Oh-Shim

    2005-01-01

    Chemical deposition of cadmium selenide (CdSe) films has been carried out from alkaline aqueous solution containing Cd 2+ and Se 2- ions. In general, the alkaline pH of the CdSe deposition bath has been adjusted by addition of liquid ammonia. However, the use of ammonia in large-scale chemical deposition method represents an environmental problem due to its volatility and toxicity. The volatility of ammonia changes the pH of deposition bath and results into irreproducible film properties. In the present paper, ammonia-free and weak alkaline (pH < 9.0) chemical method for cadmium selenide film has been developed. The cadmium selenide films are microcrystalline (grain size 0.5-0.7 μm) with hexagonal crystal structure. These films are photoactive and therefore, useful in photo conversion of light into electrical power

  13. Industrial Scale Synthesis of Carbon Nanotubes Via Fluidized Bed Chemical Vapor Deposition: A Senior Design Project

    Science.gov (United States)

    Smith, York R.; Fuchs, Alan; Meyyappan, M.

    2010-01-01

    Senior year chemical engineering students designed a process to produce 10 000 tonnes per annum of single wall carbon nanotubes (SWNT) and also conducted bench-top experiments to synthesize SWNTs via fluidized bed chemical vapor deposition techniques. This was an excellent pedagogical experience because it related to the type of real world design…

  14. Industrialization of hot wire chemical vapor deposition for thin film applications

    NARCIS (Netherlands)

    Schropp, Ruud

    2015-01-01

    The consequences of implementing a Hot Wire Chemical Vapor Deposition (HWCVD) chamber into an existing in-line or roll-to-roll reactor are described. The hardware and operation of the HWCVD production reactor is compared to that of existing roll-to-roll reactors based on Plasma Enhanced Chemical

  15. Impact of acid atmospheric deposition on soils : quantification of chemical and hydrologic processes

    NARCIS (Netherlands)

    Grinsven, van J.J.M.

    1988-01-01

    Atmospheric deposition of SO x , NOx and NHx will cause major changes in the chemical composition of solutions in acid soils, which may affect the biological functions of the soil. This thesis deals with quantification of soil acidification by means of chemical

  16. In situ investigation of wet chemical processes for chalcopyrite solar cells by L-edge XAS under ambient conditions

    Energy Technology Data Exchange (ETDEWEB)

    Greil, Stefanie M. [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Lauermann, Iver, E-mail: Iver.lauermann@helmholtz-berlin.d [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Ennaoui, Ahmed; Kropp, Timo; Lange, Kathrin M.; Weber, Matthieu [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Aziz, Emad F., E-mail: Emad.Aziz@helmholtz-berlin.d [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin (Germany)

    2010-02-15

    Two instrumental setups for in situ soft X-ray absorption spectroscopy in liquid systems are demonstrated in this work. One for investigating chemical reactions in solutions and a new one for the solid component of a liquid / (as in both / absorber) solid interface. We used these setups for investigating two production processes for chalcopyrite solar cells under ambient conditions, probing the L-edge of Zn and Cu. The first one is a flow cell with a silicon nitride membrane to study the chemical bath deposition process for Cd-free buffer layers. Examining the electronic structure of involved Zn complexes allows to determine the exact reaction mechanism taking place during this process. The second setup is a rotating disk for investigating the bath/absorber interface upon the etching process of superficial binary copper compounds of the absorber as a function of time. The time resolution of the chemical reaction demonstrated in this study ranges from the second to minute time scale.

  17. In situ investigation of wet chemical processes for chalcopyrite solar cells by L-edge XAS under ambient conditions

    International Nuclear Information System (INIS)

    Greil, Stefanie M.; Lauermann, Iver; Ennaoui, Ahmed; Kropp, Timo; Lange, Kathrin M.; Weber, Matthieu; Aziz, Emad F.

    2010-01-01

    Two instrumental setups for in situ soft X-ray absorption spectroscopy in liquid systems are demonstrated in this work. One for investigating chemical reactions in solutions and a new one for the solid component of a liquid / (as in both / absorber) solid interface. We used these setups for investigating two production processes for chalcopyrite solar cells under ambient conditions, probing the L-edge of Zn and Cu. The first one is a flow cell with a silicon nitride membrane to study the chemical bath deposition process for Cd-free buffer layers. Examining the electronic structure of involved Zn complexes allows to determine the exact reaction mechanism taking place during this process. The second setup is a rotating disk for investigating the bath/absorber interface upon the etching process of superficial binary copper compounds of the absorber as a function of time. The time resolution of the chemical reaction demonstrated in this study ranges from the second to minute time scale.

  18. In situ investigation of wet chemical processes for chalcopyrite solar cells by L-edge XAS under ambient conditions

    Science.gov (United States)

    Greil, Stefanie M.; Lauermann, Iver; Ennaoui, Ahmed; Kropp, Timo; Lange, Kathrin M.; Weber, Matthieu; Aziz, Emad F.

    2010-02-01

    Two instrumental setups for in situ soft X-ray absorption spectroscopy in liquid systems are demonstrated in this work. One for investigating chemical reactions in solutions and a new one for the solid component of a liquid / (as in both / absorber) solid interface. We used these setups for investigating two production processes for chalcopyrite solar cells under ambient conditions, probing the L-edge of Zn and Cu. The first one is a flow cell with a silicon nitride membrane to study the chemical bath deposition process for Cd-free buffer layers. Examining the electronic structure of involved Zn complexes allows to determine the exact reaction mechanism taking place during this process. The second setup is a rotating disk for investigating the bath/absorber interface upon the etching process of superficial binary copper compounds of the absorber as a function of time. The time resolution of the chemical reaction demonstrated in this study ranges from the second to minute time scale.

  19. A comparative study of the annealing behavior of Cu(In,Ga)(S,Se)2 based solar cells with an indium sulfide buffer layer, partly submitted to wet chemical treatments

    International Nuclear Information System (INIS)

    Hönes, C.; Hackenberg, J.; Zweigart, S.; Wachau, A.; Hergert, F.; Siebentritt, S.

    2015-01-01

    Indium sulfide thin films deposited via thermal evaporation from compound source material have been successfully utilized as a cadmium free buffer layer for Cu(In,Ga)Se 2 based solar cells. However, high efficiencies are only reached after an additional annealing step. In this work, the annealing behavior of Cu(In,Ga)(S,Se) 2 based indium sulfide buffered solar cells is compared to the annealing behavior of similar cells, which were submitted to wet chemical treatments partly containing cadmium ions. Upon annealing a significant improvement of the initial solar cell characteristics is observed for the untreated cell and is related to the increase of activation energy for the carrier recombination process and a decrease of the ideality factor within the one diode model. It is shown here that this improvement can also be achieved by wet treatments of the absorber prior to buffer layer deposition. Upon annealing these treated cells still gain in collection length but lose open circuit voltage, which is explained here within a model including a highly p-doped absorber surface layer and supported by simulations showing that a decrease in doping density of such a surface layer would lead to the observed effects

  20. A comparative study of the annealing behavior of Cu(In,Ga)(S,Se){sub 2} based solar cells with an indium sulfide buffer layer, partly submitted to wet chemical treatments

    Energy Technology Data Exchange (ETDEWEB)

    Hönes, C., E-mail: christian.hoenes@de.bosch.com [Corporate Research and Advance Engineering, Robert Bosch GmbH, Robert-Bosch-Straße 2, D-71701 Schwieberdingen (Germany); Laboratory for Photovoltaics, University of Luxembourg, 41 rue du Brill, L-4422 Belvaux (Luxembourg); Hackenberg, J. [Corporate Research and Advance Engineering, Robert Bosch GmbH, Robert-Bosch-Straße 2, D-71701 Schwieberdingen (Germany); Zweigart, S. [Corporate Research and Advance Engineering, Robert Bosch GmbH, Postfach 10 60 50, D-70049 Stuttgart (Germany); Wachau, A.; Hergert, F. [Bosch Solar CISTech GmbH, D-14772 Brandenburg (Germany); Siebentritt, S., E-mail: susanne.siebentritt@uni.lu [Laboratory for Photovoltaics, University of Luxembourg, 41 rue du Brill, L-4422 Belvaux (Luxembourg)

    2015-03-07

    Indium sulfide thin films deposited via thermal evaporation from compound source material have been successfully utilized as a cadmium free buffer layer for Cu(In,Ga)Se{sub 2} based solar cells. However, high efficiencies are only reached after an additional annealing step. In this work, the annealing behavior of Cu(In,Ga)(S,Se){sub 2} based indium sulfide buffered solar cells is compared to the annealing behavior of similar cells, which were submitted to wet chemical treatments partly containing cadmium ions. Upon annealing a significant improvement of the initial solar cell characteristics is observed for the untreated cell and is related to the increase of activation energy for the carrier recombination process and a decrease of the ideality factor within the one diode model. It is shown here that this improvement can also be achieved by wet treatments of the absorber prior to buffer layer deposition. Upon annealing these treated cells still gain in collection length but lose open circuit voltage, which is explained here within a model including a highly p-doped absorber surface layer and supported by simulations showing that a decrease in doping density of such a surface layer would lead to the observed effects.

  1. Evaluation of physical and chemical properties and their interactions in fat, oil, and grease (FOG) deposits.

    Science.gov (United States)

    Gross, Martin A; Jensen, Jeanette L; Gracz, Hanna S; Dancer, Jens; Keener, Kevin M

    2017-10-15

    Fat, oil and grease (FOG) blockages in sewer systems are a substantial problem in the United States. It has been estimated that over 50% of sewer overflows are a result of FOG blockages. In this work, a thorough laboratory study was undertaken to examine key variables that contribute to FOG deposit formation under controlled conditions. Physical and chemical properties and their interactions were evaluated and conditions that generated deposits that mimicked field FOG deposits were identified. It was found that 96 of the of 128 reaction conditions tested in the laboratory formed FOG deposits with similar physical and chemical characteristics as field FOG deposits. It was also found that FOG deposits can be created through fatty acid crystallization and not just saponification. Furthermore FOG deposits were found to be more complex than previously documented and contain free fatty acids, fatty acid metal salts, triacylglycerol's, diacylglycerol's and, monoacylglycerol's. Lastly it was found that FOG deposits that only contained saturated fatty acids were on average 2.1 times higher yield strength than deposits that contained unsaturated fatty acids. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. The Chemical Vapour Deposition of Tantalum - in long narrow channels

    DEFF Research Database (Denmark)

    Mugabi, James Atwoki

    protective layers of tantalum because of the process’ ability to coat complex geometries and its relative ease to control. This work focuses on studying the CVD of tantalum in long narrow channels with the view that the knowledge gained during the project can be used to optimise the commercial coating...... and that there is a major change in morphology between 850 – 900 °C. The effects of system pressure and precursor partial pressure are also studied, and were found to have relevance to the tantalum distribution along the substrates but little effect on the structural morphology of the deposited layer. In the implemented...

  3. Coating of ceramic powders by chemical vapor deposition techniques (CVD)

    International Nuclear Information System (INIS)

    Haubner, R.; Lux, B.

    1997-01-01

    New ceramic materials with selected advanced properties can be designed by coating of ceramic powders prior to sintering. By variation of the core and coating material a large number of various powders and ceramic materials can be produced. Powders which react with the binder phase during sintering can be coated with stable materials. Thermal expansion of the ceramic materials can be adjusted by varying the coating thickness (ratio core/layer). Electrical and wear resistant properties can be optimized for electrical contacts. A fluidized bed reactor will be designed which allow the deposition of various coatings on ceramic powders. (author)

  4. Chemical analysis of the Assale (Ethiopia) rock salt deposit | Binega ...

    African Journals Online (AJOL)

    contaminants) elements found in the Assale (Ethiopia) rock salt. The results showed that the rock salt is found to be the best natural common salt. This was proved by comparison with the chemical requirement and trace elements in common ...

  5. Characterization of photoluminescent europium doped yttrium oxide thin-films prepared by metallorganic chemical vapor deposition

    International Nuclear Information System (INIS)

    McKittrick, J.; Bacalski, C.F.; Hirata, G.A.; Hubbard, K.M.; Pattillo, S.G.; Salazar, K.V.; Trkula, M.

    1998-01-01

    Europium doped yttrium oxide, (Y 1-x Eu x ) 2 O 3 , thin-films were deposited on silicon and sapphire substrates by metallorganic chemical vapor deposition (MOCVD). The films were grown in a MOCVD chamber reacting yttrium and europium tris(2,2,6,6-tetramethyl-3,5,-heptanedionates) precursors in an oxygen atmosphere at low pressures (5 Torr) and low substrate temperatures (500--700 C). The films deposited at 500 C were flat and composed of nanocrystalline regions of cubic Y 2 O 3 , grown in a textured [100] or [110] orientation to the substrate surface. Films deposited at 600 C developed from the flat, nanocrystalline morphology into a plate-like growth morphology oriented in the [111] with increasing deposition time. Monoclinic Y 2 O 3 :Eu 3+ was observed in x-ray diffraction for deposition temperatures ≥600 C on both (111) Si and (001) sapphire substrates. This was also confirmed by the photoluminescent emission spectra

  6. Chemical bath deposition of indium sulphide thin films: preparation and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Lokhande, C.D.; Ennaoui, A.; Patil, P.S.; Giersig, M.; Diesner, K.; Muller, M.; Tributsch, H. [Hahn-Meitner-Institut Berlin GmbH (Germany). Bereich Physikalische Chemie

    1999-02-26

    Indium sulphide (In{sub 2}S{sub 3}) thin films have been successfully deposited on different substrates under varying deposition conditions using chemical bath deposition technique. The deposition mechanism of In{sub 2}S{sub 3} thin films from thioacetamide deposition bath has been proposed. Films have been characterized with respect to their crystalline structure, composition, optical and electrical properties by means of X-ray diffraction, TEM, EDAX, optical absorption, TRMC (time resolved microwave conductivity) and RBS. Films on glass substrates were amorphous and on FTO (flourine doped tin oxide coated) glass substrates were polycrystalline (element of phase). The optical band gap of In{sub 2}S{sub 3} thin film was estimated to be 2.75 eV. The as-deposited films were photoactive as evidenced by TRMC studies. The presence of oxygen in the film was detected by RBS analysis. (orig.) 27 refs.

  7. Two dimensional radial gas flows in atmospheric pressure plasma-enhanced chemical vapor deposition

    Science.gov (United States)

    Kim, Gwihyun; Park, Seran; Shin, Hyunsu; Song, Seungho; Oh, Hoon-Jung; Ko, Dae Hong; Choi, Jung-Il; Baik, Seung Jae

    2017-12-01

    Atmospheric pressure (AP) operation of plasma-enhanced chemical vapor deposition (PECVD) is one of promising concepts for high quality and low cost processing. Atmospheric plasma discharge requires narrow gap configuration, which causes an inherent feature of AP PECVD. Two dimensional radial gas flows in AP PECVD induces radial variation of mass-transport and that of substrate temperature. The opposite trend of these variations would be the key consideration in the development of uniform deposition process. Another inherent feature of AP PECVD is confined plasma discharge, from which volume power density concept is derived as a key parameter for the control of deposition rate. We investigated deposition rate as a function of volume power density, gas flux, source gas partial pressure, hydrogen partial pressure, plasma source frequency, and substrate temperature; and derived a design guideline of deposition tool and process development in terms of deposition rate and uniformity.

  8. Effect of Different Catalyst Deposition Technique on Aligned Multiwalled Carbon Nanotubes Grown by Thermal Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    Mohamed Shuaib Mohamed Saheed

    2014-01-01

    Full Text Available The paper reported the investigation of the substrate preparation technique involving deposition of iron catalyst by electron beam evaporation and ferrocene vaporization in order to produce vertically aligned multiwalled carbon nanotubes array needed for fabrication of tailored devices. Prior to the growth at 700°C in ethylene, silicon dioxide coated silicon substrate was prepared by depositing alumina followed by iron using two different methods as described earlier. Characterization analysis revealed that aligned multiwalled carbon nanotubes array of 107.9 µm thickness grown by thermal chemical vapor deposition technique can only be achieved for the sample with iron deposited using ferrocene vaporization. The thick layer of partially oxidized iron film can prevent the deactivation of catalyst and thus is able to sustain the growth. It also increases the rate of permeation of the hydrocarbon gas into the catalyst particles and prevents agglomeration at the growth temperature. Combination of alumina-iron layer provides an efficient growth of high density multiwalled carbon nanotubes array with the steady growth rate of 3.6 µm per minute for the first 12 minutes and dropped by half after 40 minutes. Thicker and uniform iron catalyst film obtained from ferrocene vaporization is attributed to the multidirectional deposition of particles in the gaseous form.

  9. Surfactant-induced deposit structures in relation to the biological efficacy of glyphosate on easy- and difficult-to-wet weed species.

    Science.gov (United States)

    Kraemer, Thorsten; Hunsche, Mauricio; Noga, Georg

    2009-08-01

    Typical active ingredient (AI) residue patterns are formed during droplet drying on plant surfaces owing to the interaction of spray solution characteristics and leaf micromorphology. Currently, comparatively little is known about the influence of AI deposit patterns within a spray droplet residue area on the penetration and biological efficacy of glyphosate. A scanning electron microscope with energy dispersive X-ray microanalysis has been used to characterise residue patterns and to quantify the area ultimately covered by glyphosate within the droplet spread area. The easy-to-wet weed species Stellaria media L. and Viola arvensis L., as well as the difficult-to-wet Chenopodium album L. and Setaria viridis L., differing in their surface micromorphology, have been used. Rapeseed oil ethoxylates (RSO 5 or RSO 60) were added to glyphosate solutions to provide different droplet spread areas. Addition of RSO 5 enhanced droplet spread area more than RSO 60, and both caused distinct glyphosate residue patterns. The biological efficacy of treatment solutions showed no significant correlation with the area ultimately covered by glyphosate. The results have implications on herbicide uptake models. This study shows that droplet spread area does not correspond to the area ultimately covered by glyphosate, and that the latter does not affect glyphosate phytotoxicity.

  10. Identification sources of pollen spectra in dry and wet atmospheric deposition in the forest-steppe zone of Altai Krai (Russia)

    Science.gov (United States)

    Ryabchinskaya, Natalia; Nenasheva, Galina; Malygina, Natalia

    2015-04-01

    Pollen spectra circulating in the atmosphere contain the important information about primary biological aerosol particles (PBAP), worldwide interest in which has significantly increased in recent decades [Despres, 2012]. It is related to the fact that many researchers suggest primary aerosols as a condensation nucleus significantly affected on the formation of clouds and precipitation and, consequently, on the hydrological cycle and climate, especially at the regional level [Andreae et al., 2008; Poschlet et al., 2010; Prenni et al., 2009]. We present the comparison of pollen spectra obtained during the dry and wet atmospheric deposition in Altai Krai (Russia) and identification of the sources/regions of their receipts. Altai Krai is located in the center of the Eurasian continent, at the border of several natural and climatic zones. A significant part of the region's territory is characterized as a forest-steppe zone with a lot of natural and anthropogenic landscapes, accompanied by continental climate. It provides a rich diversity of natural vegetation and cultural associations. During last 10 years pollen grains has been monitored in the airspace of Barnaul city (the capital of Altai Krai) located in the central part of the forest-steppe zone). During the monitoring, the attempts to determine the origin of pollen spectra (local or introduced) were made as well. In the long-term average dates of the first wave of dusting in the spring season 2014 Burkard pollen traps were used in order to monitor the airspace in Barnaul, namely dry deposition of pollen grains [Nenasheva, 2013]. To estimate the wet deposition PBAP (pollen), which can reach 80% in the middle latitudes, precipitation sampler were installed close to Burkard pollen traps in order to sample precipitation. The samples were filtered through a filter having a pore diameter of 1 µm, then prepared and examined for the presence of pollen grains. The comparison of the results of pollen analysis of 10 samples

  11. Database development for understanding the wet deposition and dispersion processes after the Fukushima nuclear plant accident. Radar data

    International Nuclear Information System (INIS)

    Yatagai, Akiyo; Takara, Kaoru; Ishihara, Masahito; Ishikawa, Hirohiko; Watanabe, Akira; Murata, Ken T.

    2015-01-01

    This manuscript describes datasets of meteorological information being developed for understanding the dispersion and deposition process of radionuclides associated with the Fukushima accident in March 2011. Among several products, this paper reports mainly our original radar data images including the X-band radar data from Fukushima University as well as the three-dimensional reflectivity data from the Japan Meteorological Agency C-band radar network. (author)

  12. Spatial variations of wet deposition rates in an extended region of complex topography deduced from measurements of 210Pb soil inventories

    International Nuclear Information System (INIS)

    Branford, D.; Mourne, R.W.; Fowler, D.

    1998-01-01

    The radionuclide 210 Pb derived from gaseous 222 Rn present in the atmosphere becomes attached to the same aerosols as the bulk of the main pollutants sulphur and nitrogen. When scavenged from the atmosphere by precipitation, the 210 Pb is readily attached to organic matter in the surface horizons of the soil. Inventories of 210 Pb in soil can thus be used to measure the spatial variations in wet (or cloud) deposition due to orography averaged over many precipitation events (half-life of 210 Pb is 22·3 year). Measurements of soil 210 Pb inventories were made along a transect through complex terrain in the Scottish Highlands to quantify the orographic enhancement of wet deposition near the summits of the three mountains Ben Cruachan, Beinn Dorain and Ben Lawers, which, respectively, lie at distances of approximately 30, 55 and 80 km from the coast in the direction of the prevailing wind. The inventory of 210 Pb on the wind-facing slopes of Ben Cruachan shows an increase with altitude that rises faster than the precipitation rate, which is indicative of seeder-feeder scavenging of orographic cloud occurring around the summit. Results for Beinn Dorain show a smaller rise with altitude whereas those for Ben Lawers give no indication of a rise. It is concluded that the seeder-feeder mechanism in regions of complex topology decreases in effectiveness as a function of distance inland along the direction of the prevailing wind. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  13. Low-pressure chemical vapour deposition of LiCoO2 thin films: a systematic investigation of the deposition parameters

    NARCIS (Netherlands)

    Oudenhoven, J.F.M.; Dongen, van T.; Niessen, R.A.H.; Croon, de M.H.J.M.; Notten, P.H.L.

    2009-01-01

    The feasibility of volatile precursor low-pressure chemical vapor deposition (LPCVD) for the production of LiCoO2 cathodes for all solid-state microbatteries was examined. To test this feasibility, and gain insight into the deposition behavior, the influence of the deposition parameters on the

  14. Chemical characterization of condensates from the Shatlyk deposit

    Energy Technology Data Exchange (ETDEWEB)

    Khankuliev, K.; Makarov, V.V.; Talalaev, E.I.

    1980-01-01

    Condensates from the deposits of Eastern and Western Shatlyk differ little in terms of fractional and group hydrocarbon composition. They are all comparatively light, boil away by 350/sup 0/, while the benzene part (60-200/sup 0/) amounts to 43-44% and the kerosene part (200-300/sup 0/), 39-42%. The basic part of the cyclic hydrocarbons (naphthene and aromatic) is concentrated in the light condensate fractions, which boil away by 150/sup 0/. The total content of the aromatic hydrocarbons in the condensates is at most 10%. The 150-200/sup 0/ fractions is 85% paraffin hydrocarbons, while ramified and nonramified structures of paraffin hydrocarbons are found in equal quantities.

  15. Structural, mechanical, electrical and wetting properties of ZrNx films deposited by Ar/N2 vacuum arc discharge: Effect of nitrogen partial pressure

    Science.gov (United States)

    Abdallah, B.; Naddaf, M.; A-Kharroub, M.

    2013-03-01

    Non-stiochiometric zirconium nitride (ZrNx) thin films have been deposited on silicon substrates by vacuum arc discharge of (N2 + Ar) gas mixtures at different N2 partial pressure ratio. The microstructure, mechanical, electrical and wetting properties of these films are studied by means of X-ray diffraction (XRD), micro-Raman spectroscopy, Rutherford back scattering (RBS) technique, conventional micro-hardness testing, electrical resistivity, atomic force microscopy (AFM) and contact angle (CA) measurements. RBS results and analysis show that the (N/Zr) ratio in the film increases with increasing the N2 partial pressure. A ZrNx film with (Zr/N) ratio in the vicinity of stoichiometric ZrN is obtained at N2 partial pressure of 10%. XRD and Raman results indicate that all deposited films have strained cubic crystal phase of ZrN, regardless of the N2 partial pressure. On increasing the N2 partial pressure, the relative intensity of (1 1 1) orientation with respect to (2 0 0) orientation is seen to decrease. The effect of N2 partial pressure on micro-hardness and the resistivity of the deposited film is revealed and correlated to the alteration of grain size, crystallographic texture, stoichiometry and residual stress developed in the film. In particular, it is found that residual stress and nitrogen incorporation in the film play crucial role in the alteration of micro-hardness and resistivity respectively. In addition, CA and AFM results demonstrate that as N2 partial pressure increases, both the surface hydrophobicity and roughness of the deposited film increase, leading to a significant decrease in the film surface free energy (SFE).

  16. Comparison of the chemical properties of wheat straw and beech fibers following alkaline wet oxidation and laccase treatments

    DEFF Research Database (Denmark)

    Schmidt, A. S.; Mallon, S.; Thomsen, Anne Belinda

    2002-01-01

    Wheat straw (Triticum aestivum) and beech (Fagus sylvatica), were used to evaluate the effects of two pre-treatment processes (alkaline wet oxidation and enzyme treatment with laccase) on lignocellulosic materials for applications in particleboards and fiberboards. Wheat straw and beech fibers...... treatment gave a more reactive surface than alkaline wet oxidation for wheat straw, whereas the opposite was observed for beech. Fourier transform infrared (FT-IR) spectroscopy showed an almost complete loss of the ester carbonyl stretching signal and the corresponding C-C-O stretching in wet...

  17. Deposition of titanium coating on SiC fiber by chemical vapor deposition with Ti-I{sub 2} system

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Xian, E-mail: luo_shenfan@hotmail.com; Wu, Shuai; Yang, Yan-qing; Jin, Na; Liu, Shuai; Huang, Bin

    2017-06-01

    Highlights: • The transformation paths of (Ti + I{sub 2}) powder to Ti coating is: Ti + I{sub 2} → (TiI{sub 2}, TiI{sub 3}) → Ti. • Uniform coating was obtained on SiC fiber, but it contained Si and C elements. • Deposition rate of the coating increased with the increase of temperature. • Deposition thickness increased with time and achieved the maximum at 90 min. - Abstract: Titanium coating was prepared on SiC fiber using titanium-iodine (Ti-I{sub 2}) mixture by hot-wall chemical vapor deposition. Thermodynamic analysis and experimental observation were carried out in this work. The thermodynamic analysis of the reactions in the Ti-I{sub 2} system indicates that Ti and I{sub 2} raw powder materials transform to titanium coating as follows: Ti + I{sub 2} → (TiI{sub 2}, TiI{sub 3}), and (TiI{sub 2}, TiI{sub 3}) → Ti. In theory, the conversions of TiI{sub 3} and TiI{sub 2} reach the maximum when Ti:I{sub 2} is 1:1.5, while in actual experiment that reached the maximum when Ti:I{sub 2} was 1:2, as there existed the waste of I{sub 2} due to sublimation. Typical deposited coating is relatively flat and uniform. However, as SiC is prone to react with Ti at high temperatures, the obtained coating contained some Si and C elements except for Ti. So the coating was not a pure Ti coating but contained some carbides and silicides. Deposition rate of the coating increased with the increase of temperature. The deposited thickness increased with the increase of heat preservation time, and achieved the maximum thickness at 90 min.

  18. Novel morphology of chemical vapor deposited diamond films

    Energy Technology Data Exchange (ETDEWEB)

    Tang, C.J. [I3N and Department of Physics, University of Aveiro (Portugal); Jiangsu Key Laboratory for Advanced Functional Materials and Department of Physics, Changshu Institute of Technology, Changshu (China); TEMA and Department of Mechanical Engineering, University of Aveiro (Portugal); Fernandes, A.J.S.; Abe, I.; Pinto, J.L. [I3N and Department of Physics, University of Aveiro (Portugal); Gracio, J. [TEMA and Department of Mechanical Engineering, University of Aveiro (Portugal); Buijnsters, J.G. [Institute for Molecules and Materials (IMM), Radboud University Nijmegen (Netherlands)

    2010-04-15

    We have obtained simultaneously nanocrystalline and {l_brace}100{r_brace} faceted large-grained polycrystalline diamond films not only on different substrates but also on the same substrate in only one deposition run using a novel approach for substrate arrangement. Furthermore, interesting unusual morphologies and microstructures composed by non-faceted nanostructures and terminated with large smooth {l_brace}100{r_brace} facet-like belt are found near the edges of the top square sample. The morphology variation is likely caused by the so called edge effect, where a strong variation in temperature is also present. We have modelled the temperature distribution on the substrates by computer simulations using the finite element method. The novel feature, namely the coexistence of oval non-faceted nanocrystalline diamond grains and large smooth {l_brace}100{r_brace} facet-like belt in one diamond grain, is in the transition from {l_brace}100{r_brace} faceted polycrystalline diamond to cauliflower-like nanocrystalline diamond. The formation mechanism is discussed based on the temperature analysis and other simulation results described in the literature. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  19. Investigation of deposition characteristics and properties of high-rate deposited silicon nitride films prepared by atmospheric pressure plasma chemical vapor deposition

    International Nuclear Information System (INIS)

    Kakiuchi, H.; Nakahama, Y.; Ohmi, H.; Yasutake, K.; Yoshii, K.; Mori, Y.

    2005-01-01

    Silicon nitride (SiN x ) films have been prepared at extremely high deposition rates by the atmospheric pressure plasma chemical vapor deposition (AP-PCVD) technique on Si(001) wafers from gas mixtures containing He, H 2 , SiH 4 and N 2 or NH 3 . A 150 MHz very high frequency (VHF) power supply was used to generate high-density radicals in the atmospheric pressure plasma. Deposition rate, composition and morphology of the SiN x films prepared with various deposition parameters were studied by scanning electron microscopy and Auger electron spectroscopy. Fourier transformation infrared (FTIR) absorption spectroscopy was also used to characterize the structure and the chemical bonding configurations of the films. Furthermore, etching rate with buffered hydrofluoric acid (BHF) solution, refractive index and capacitance-voltage (C-V) characteristics were measured to evaluate the dielectric properties of the films. It was found that effective passivation of dangling bonds and elimination of excessive hydrogen atoms at the film-growing surface seemed to be the most important factor to form SiN x film with a dense Si-N network. The C-V curve of the optimized film showed good interface properties, although further improvement was necessary for use in the industrial metal-insulator-semiconductor (MIS) applications

  20. The development of chemically vapor deposited mullite coatings for the corrosion protection of SiC

    Energy Technology Data Exchange (ETDEWEB)

    Auger, M.; Hou, P.; Sengupta, A.; Basu, S.; Sarin, V. [Boston Univ., MA (United States)

    1998-05-01

    Crystalline mullite coatings have been chemically vapor deposited onto SiC substrates to enhance the corrosion and oxidation resistance of the substrate. Current research has been divided into three distinct areas: (1) Development of the deposition processing conditions for increased control over coating`s growth rate, microstructure, and morphology; (2) Analysis of the coating`s crystal structure and stability; (3) The corrosion resistance of the CVD mullite coating on SiC.

  1. Strain and Structure Heterogeneity in MoS2 Atomic Layers Grown by Chemical Vapour Deposition

    Science.gov (United States)

    2014-11-18

    cture heterogeneity in MoS2 atomiclayers grown by chemical vapour deposition 6. AUTHORS Zheng Liu, Matin Amani, Sina Najmaei, Quan Xu, Xiaolong Zou...deposition Zheng Liu1•2•3·*, Matin Amani4·*, Sina Najmaei5·*, Quan Xu6•7, Xiaolong Zou5, Wu Zhou8, Ting Yu9, Caiyu Qiu9, A Glen Birdwell4, Frank J. Crowne4

  2. Green electroluminescence from ZnO/n-InP heterostructure fabricated by metalorganic chemical vapour deposition

    International Nuclear Information System (INIS)

    Zhu Huichao; Zhang Baolin; Li Xiangping; Dong Xin; Li Wancheng; Guan Hesong; Cui Yongguo; Xia Xiaochuan; Yang Tianpeng; Chang Yuchun; Du Guotong

    2007-01-01

    Vertically aligned ZnO films were deposited on n-InP by metalorganic chemical vapour deposition. X-ray diffraction, field emission scanning electron microscopy and photoluminescence measurements demonstrated that the ZnO films had good quality. By evaporating AuZn electrodes on both ZnO and InP surfaces, a ZnO-based light emitting device was fabricated. Under forward voltage, weak green emissions can be observed in darkness

  3. Properties of amorphous silicon thin films synthesized by reactive particle beam assisted chemical vapor deposition

    International Nuclear Information System (INIS)

    Choi, Sun Gyu; Wang, Seok-Joo; Park, Hyeong-Ho; Jang, Jin-Nyoung; Hong, MunPyo; Kwon, Kwang-Ho; Park, Hyung-Ho

    2010-01-01

    Amorphous silicon thin films were formed by chemical vapor deposition of reactive particle beam assisted inductively coupled plasma type with various reflector bias voltages. During the deposition, the substrate was heated at 150 o C. The effects of reflector bias voltage on the physical and chemical properties of the films were systematically studied. X-ray diffraction and Raman spectroscopy results showed that the deposited films were amorphous and the films under higher reflector voltage had higher internal energy to be easily crystallized. The chemical state of amorphous silicon films was revealed as metallic bonding of Si atoms by using X-ray photoelectron spectroscopy. An increase in reflector voltage induced an increase of surface morphology of films and optical bandgap and a decrease of photoconductivity.

  4. Fibrous hydroxyapatite–carbon nanotube composites by chemical vapor deposition: In situ fabrication, structural and morphological characterization

    International Nuclear Information System (INIS)

    Kosma, Vassiliki; Tsoufis, Theodoros; Koliou, Theodora; Kazantzis, Antonios; Beltsios, Konstantinos; De Hosson, Jeff Th. M.; Gournis, Dimitrios

    2013-01-01

    Highlights: ► CNTs synthesized on fibrous HA surfaces supporting Fe–Co bi- metallic catalysts by CVD. ► CNTs are rooted on HA distinct needle-like monocrystals and needle spherulitic aggregates. ► Reaction temperature and metal loading are critical parameters for CNT production. -- Abstract: Fibrous hydroxyapatite (HA)–carbon nanotube composites were synthesized by the catalytic decomposition of acetylene over Fe–Co bimetallic catalysts supported on the fibrous HA. Two forms of fibrous HA (distinct needle-like monocrystals and spherulitic aggregates of needles) were synthesized using a simple precipitation method and loaded with bimetallic catalysts (from 2 up to 20 wt%) by a wet chemical impregnation method. The HA supported catalysts were evaluated for the in situ growth of carbon nanotubes using the catalytic chemical vapor deposition method. The effect of reaction temperature and metal loading on the yield, structural perfection and morphology of the carbon products were investigated using a combination of X-ray diffraction, thermal analysis, Raman spectroscopy and scanning and transmission electron microscopies. The results revealed that both the selection of the growing conditions and the metal loading determine the yield and overall quality of the synthesized carbon nanotubes, which exhibit high graphitization degree when synthesized in high yields

  5. Fibrous hydroxyapatite–carbon nanotube composites by chemical vapor deposition: In situ fabrication, structural and morphological characterization

    Energy Technology Data Exchange (ETDEWEB)

    Kosma, Vassiliki; Tsoufis, Theodoros; Koliou, Theodora [Department of Materials Science and Engineering, University of Ioannina, GR-45110 Ioannina (Greece); Kazantzis, Antonios [Department of Applied Physics, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, NL-9747AG Groningen (Netherlands); Beltsios, Konstantinos [Department of Materials Science and Engineering, University of Ioannina, GR-45110 Ioannina (Greece); De Hosson, Jeff Th. M. [Department of Applied Physics, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, NL-9747AG Groningen (Netherlands); Gournis, Dimitrios, E-mail: dgourni@cc.uoi.gr [Department of Materials Science and Engineering, University of Ioannina, GR-45110 Ioannina (Greece)

    2013-04-20

    Highlights: ► CNTs synthesized on fibrous HA surfaces supporting Fe–Co bi- metallic catalysts by CVD. ► CNTs are rooted on HA distinct needle-like monocrystals and needle spherulitic aggregates. ► Reaction temperature and metal loading are critical parameters for CNT production. -- Abstract: Fibrous hydroxyapatite (HA)–carbon nanotube composites were synthesized by the catalytic decomposition of acetylene over Fe–Co bimetallic catalysts supported on the fibrous HA. Two forms of fibrous HA (distinct needle-like monocrystals and spherulitic aggregates of needles) were synthesized using a simple precipitation method and loaded with bimetallic catalysts (from 2 up to 20 wt%) by a wet chemical impregnation method. The HA supported catalysts were evaluated for the in situ growth of carbon nanotubes using the catalytic chemical vapor deposition method. The effect of reaction temperature and metal loading on the yield, structural perfection and morphology of the carbon products were investigated using a combination of X-ray diffraction, thermal analysis, Raman spectroscopy and scanning and transmission electron microscopies. The results revealed that both the selection of the growing conditions and the metal loading determine the yield and overall quality of the synthesized carbon nanotubes, which exhibit high graphitization degree when synthesized in high yields.

  6. Effects of heat treatment on the microstructure of amorphous boron carbide coating deposited on graphite substrates by chemical vapor deposition

    International Nuclear Information System (INIS)

    Li Siwei; Zeng Bin; Feng Zude; Liu Yongsheng; Yang Wenbin; Cheng Laifei; Zhang Litong

    2010-01-01

    A two-layer boron carbide coating is deposited on a graphite substrate by chemical vapor deposition from a CH 4 /BCl 3 /H 2 precursor mixture at a low temperature of 950 o C and a reduced pressure of 10 KPa. Coated substrates are annealed at 1600 o C, 1700 o C, 1800 o C, 1900 o C and 2000 o C in high purity argon for 2 h, respectively. Structural evolution of the coatings is explored by electron microscopy and spectroscopy. Results demonstrate that the as-deposited coating is composed of pyrolytic carbon and amorphous boron carbide. A composition gradient of B and C is induced in each deposition. After annealing, B 4 C crystallites precipitate out of the amorphous boron carbide and grow to several hundreds nanometers by receiving B and C from boron-doped pyrolytic carbon. Energy-dispersive spectroscopy proves that the crystallization is controlled by element diffusion activated by high temperature annealing, after that a larger concentration gradient of B and C is induced in the coating. Quantified Raman spectrum identifies a graphitization enhancement of pyrolytic carbon. Transmission electron microscopy exhibits an epitaxial growth of B 4 C at layer/layer interface of the annealed coatings. Mechanism concerning the structural evolution on the basis of the experimental results is proposed.

  7. Surface modification of reverse osmosis desalination membranes by thin-film coatings deposited by initiated chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Ozaydin-Ince, Gozde, E-mail: gozdeince@sabanciuniv.edu [Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Matin, Asif, E-mail: amatin@mit.edu [Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Khan, Zafarullah, E-mail: zukhan@mit.edu [Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Zaidi, S.M. Javaid, E-mail: zaidismj@kfupm.edu.sa [Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Gleason, Karen K., E-mail: kkgleasn@mit.edu [Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2013-07-31

    Thin-film polymeric reverse osmosis membranes, due to their high permeation rates and good salt rejection capabilities, are widely used for seawater desalination. However, these membranes are prone to biofouling, which affects their performance and efficiency. In this work, we report a method to modify the membrane surface without damaging the active layer or significantly affecting the performance of the membrane. Amphiphilic copolymer films of hydrophilic hydroxyethylmethacrylate and hydrophobic perfluorodecylacrylate (PFA) were synthesized and deposited on commercial RO membranes using an initiated chemical vapor deposition technique which is a polymer deposition technique that involves free-radical polymerization initiated by gas-phase radicals. Relevant surface characteristics such as hydrophilicity and roughness could be systematically controlled by varying the polymer chemistry. Increasing the hydrophobic PFA content in the films leads to an increase in the surface roughness and hydrophobicity. Furthermore, the surface morphology studies performed using the atomic force microscopy show that as the thickness of the coating increases average surface roughness increases. Using this knowledge, the coating thickness and chemistry were optimized to achieve high permeate flux and to reduce cell attachment. Results of the static bacterial adhesion tests show that the attachment of bacterial cells is significantly reduced on the coated membranes. - Highlights: • Thin films are deposited on reverse osmosis membranes. • Amphiphilic thin films are resistant to protein attachment. • The permeation performance of the membranes is not affected by the coating. • The thin film coatings delayed the biofouling.

  8. Electrochromic and electrochemical capacitive properties of tungsten oxide and its polyaniline nanocomposite films obtained by chemical bath deposition method

    CSIR Research Space (South Africa)

    Nwanya, AC

    2014-05-01

    Full Text Available Polyanine and its nanocomposite WO3/PANI films were deposited on fluorine doped tin oxide (FTO) glassslides by simple chemical bath deposition method. The morphology structure of the composite film wasstudied using atomic force microscopy (AFM...

  9. New insights into the mixing of gold and copper in a nanoparticle from a structural study of Au-Cu nanoalloys synthesized via a wet chemistry method and pulsed laser deposition.

    Science.gov (United States)

    Prunier, Hélène; Nelayah, Jaysen; Ricolleau, Christian; Wang, Guillaume; Nowak, Sophie; Lamic-Humblot, Anne-Félicie; Alloyeau, Damien

    2015-11-14

    Gold-copper nanoparticles (Au-Cu NPs) were elaborated by both chemical (polyol reduction method) and physical (laser deposition) routes. The size, composition and crystal structure of these bimetallic nanoalloys were then characterized by aberration corrected transmission electron microscopy (TEM). Using a one-pot polyol method, Au-Cu nanocubes (NCs) with nominal compositions Au3Cu and AuCu3 were synthesized. The size and composition of the NCs were tuned by varying the amount and the ratio of Au(iii) and Cu(ii) ions used as metallic precursors in the reaction. While the particle shape and size were well-controlled, single particle X-ray spectroscopy showed that, irrespective of the targeted compositions, the Cu content in all NCs was about 11-12 at%, i.e. in both samples, the real composition was different from the nominal one. This was ascribed to an incomplete alloying of the two constituent metals of the alloy in the cubes due to different reduction kinetics of the two metallic precursors. To shed light on the alloying of gold and copper at the nanoscale, Au-Cu NPs with targeted compositions Au3Cu and AuCu3 were deposited on amorphous carbon by laser ablation of two monometallic sources, and their structural properties were studied by TEM. These studies show that Au-Cu nanoalloys were synthesized in both samples and that the complete mixing of Au and Cu atoms achieved with this synthesis technique led to the production of Au-Cu NPs with well-controlled compositions. These results constitute a first but major step towards a complete understanding of the details of kinetics and thermodynamics determining the mixing of gold and copper atoms at the nanoscale. Such an understanding is essential for producing Au-Cu bimetallic nanoalloys with well-defined structural properties via wet chemical synthesis.

  10. Facile synthesis of graphene on single mode fiber via chemical vapor deposition

    International Nuclear Information System (INIS)

    Zhang, C.; Man, B.Y.; Jiang, S.Z.; Yang, C.; Liu, M.; Chen, C.S.; Xu, S.C.; Feng, D.J.; Bi, D.; Liu, F.Y.; Qiu, H.W.

    2014-01-01

    Direct deposition of graphene film on the standard single mode fiber is offered using a Cu-vapor-assisted chemical vapor deposition system. The gas flow of H 2 and Ar before the growth process plays a crucial role for the direct deposition of the graphene film and the layers of the graphene can be controlled by the growth time. With a large gas flow, Cu atoms are carried off with the gas flow and hard to deposit on the surface of the single mode fiber before the growth process. Consequently, uniform graphene film is obtained in this case. On the contrary, with a lower one, Cu atoms is facile to deposit on the surface of the single mode fiber and form nanodots acting as active catalytic sites for the growth of carbon nanotubes. This method presents us a promising transfer-free technique for fabrication of the photonic applications.

  11. Chemical Bath Deposition and Characterization of CdS layer for CZTS Thin Film Solar Cell

    OpenAIRE

    Kamal, Tasnim; Parvez, Sheikh; Matin, Rummana; Bashar, Mohammad Shahriar; Hossain, Tasnia; Sarwar, Hasan; Rashid, Mohammad Junaebur

    2016-01-01

    CZTS is a new type of an absorber and abundant materials for thin film solar cells (TFSC). Cadmium sulfide (CdS) is the n-type buffer layer of it with band gap of 2.42 eV. Cadmium sulfide (CdS) buffer layer of CZTS solar cell was deposited on soda-lime glass substrates by the Chemical Bath Deposition(CBD) method, using anhydrous Cadmium chloride(CdCl_2) and Thiourea (CS(NH_2)_2). Deposition of CdS using CBD is based on the slow release of Cd^ ions and S^ ions in an alkaline bath which is achi...

  12. An economic analysis of the deposition of electrochromic WO3 via sputtering or plasma enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    Garg, D.; Henderson, P.B.; Hollingsworth, R.E.; Jensen, D.G.

    2005-01-01

    The costs of manufacturing electrochromic WO 3 thin films deposited by either radio frequency plasma enhanced chemical vapor deposition (PECVD) or DC reactive magnetron sputtering of metal targets were modeled. Both inline systems for large area glass substrates and roll-to-roll systems for flexible webs were compared. Costs of capital, depreciation, raw materials, labor, power, and other miscellaneous items were accounted for in the model. The results predict that on similar sized systems, PECVD can produce electrochromic WO 3 for as little as one-third the cost, and have more than 10 times the annual production capacity of sputtering. While PECVD cost is dominated by raw materials, primarily WF 6 , sputtering cost is dominated by labor and depreciation

  13. An economic analysis of the deposition of electrochromic WO{sub 3} via sputtering or plasma enhanced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Garg, D. [Air Products and Chemicals Inc., 7201 Hamilton Blvd., Allentown, PA 18195-7201 (United States); Henderson, P.B. [Air Products and Chemicals Inc., 7201 Hamilton Blvd., Allentown, PA 18195-7201 (United States)]. E-mail: henderpb@airproducts.co; Hollingsworth, R.E. [ITN Energy Systems Inc., 8130 Shaffer Pkwy, Littleton, CO 80127 (United States); Jensen, D.G. [ITN Energy Systems Inc., 8130 Shaffer Pkwy, Littleton, CO 80127 (United States)

    2005-06-15

    The costs of manufacturing electrochromic WO{sub 3} thin films deposited by either radio frequency plasma enhanced chemical vapor deposition (PECVD) or DC reactive magnetron sputtering of metal targets were modeled. Both inline systems for large area glass substrates and roll-to-roll systems for flexible webs were compared. Costs of capital, depreciation, raw materials, labor, power, and other miscellaneous items were accounted for in the model. The results predict that on similar sized systems, PECVD can produce electrochromic WO{sub 3} for as little as one-third the cost, and have more than 10 times the annual production capacity of sputtering. While PECVD cost is dominated by raw materials, primarily WF{sub 6}, sputtering cost is dominated by labor and depreciation.

  14. Human serum albumin (HSA) adsorption onto a-SiC:H thin films deposited by hot wire chemical vapor deposition

    International Nuclear Information System (INIS)

    Swain, Bibhu P.

    2006-01-01

    In the present paper, we report the study of the adsorption behavior of human serum albumin (HSA) onto surfaces of a-SiC:H thin films deposited by using the hot wire chemical vapor deposition (HWCVD) technique. The surface composition and surface energy of the various substrates as well as the evaluation of the adsorbed amount of protein has been carried out by means of X-ray photoelectron spectroscopy (XPS), Fourier transform infra-red (FTIR) spectroscopy, AFM and contact angle measurements. At the immediate effect of HSA interaction with a-SiC:H films N is adsorbed on the surface and stabilized after 3 days. Preliminary observation found that Si and O atom are desorbed from the surface while C and N set adsorbed to the surface of the a-SiC:H film

  15. Human serum albumin (HSA) adsorption onto a-SiC:H thin films deposited by hot wire chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Swain, Bibhu P. [Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology, Bombay (India) and Samtel Centre for Display Technologies, Indian Institute of Technology Kanpur, India, Kanpur 208016 (India)]. E-mail: bibhup@iitb.ac.in

    2006-12-15

    In the present paper, we report the study of the adsorption behavior of human serum albumin (HSA) onto surfaces of a-SiC:H thin films deposited by using the hot wire chemical vapor deposition (HWCVD) technique. The surface composition and surface energy of the various substrates as well as the evaluation of the adsorbed amount of protein has been carried out by means of X-ray photoelectron spectroscopy (XPS), Fourier transform infra-red (FTIR) spectroscopy, AFM and contact angle measurements. At the immediate effect of HSA interaction with a-SiC:H films N is adsorbed on the surface and stabilized after 3 days. Preliminary observation found that Si and O atom are desorbed from the surface while C and N set adsorbed to the surface of the a-SiC:H film.

  16. Acid Deposition Phenomena

    International Nuclear Information System (INIS)

    Ramadan, A.E.K.

    2004-01-01

    Acid deposition, commonly known as acid rain, occurs when emissions from the combustion of fossil fuels and other industrial processes undergo complex chemical reactions in the atmosphere and fall to the earth as wet deposition (rain, snow, cloud, fog) or dry deposition (dry particles, gas). Rain and snow are already naturally acidic, but are only considered problematic when less than a ph of 5.0 The main chemical precursors leading to acidic conditions are atmospheric concentrations of sulfur dioxide (SO 2 ) and nitrogen oxides (NO x ). When these two compounds react with water, oxygen, and sunlight in the atmosphere, the result is sulfuric (H 2 SO 4 ) and nitric acids (HNO 3 ), the primary agents of acid deposition which mainly produced from the combustion of fossil fuel and from petroleum refinery. Airborne chemicals can travel long distances from their sources and can therefore affect ecosystems over broad regional scales and in locations far from the sources of emissions. According to the concern of petroleum ministry with the environment and occupational health, in this paper we will discussed the acid deposition phenomena through the following: Types of acidic deposition and its components in the atmosphere Natural and man-made sources of compounds causing the acidic deposition. Chemical reactions causing the acidic deposition phenomenon in the atmosphere. Factors affecting level of acidic deposition in the atmosphere. Impact of acid deposition. Procedures for acidic deposition control in petroleum industry

  17. Coordination number constraint models for hydrogenated amorphous Si deposited by catalytic chemical vapour deposition

    Science.gov (United States)

    Kawahara, Toshio; Tabuchi, Norikazu; Arai, Takashi; Sato, Yoshikazu; Morimoto, Jun; Matsumura, Hideki

    2005-02-01

    We measured structure factors of hydrogenated amorphous Si by x-ray diffraction and analysed the obtained structures using a reverse Monte Carlo (RMC) technique. A small shoulder in the measured structure factor S(Q) was observed on the larger Q side of the first peak. The RMC results with an unconstrained model did not clearly show the small shoulder. Adding constraints for coordination numbers 2 and 3, the small shoulder was reproduced and the agreement with the experimental data became better. The ratio of the constrained coordination numbers was consistent with the ratio of Si-H and Si-H2 bonds which was estimated by the Fourier transformed infrared spectra of the same sample. This shoulder and the oscillation of the corresponding pair distribution function g(r) at large r seem to be related to the low randomness of cat-CVD deposited a-Si:H.

  18. Coordination number constraint models for hydrogenated amorphous Si deposited by catalytic chemical vapour deposition

    International Nuclear Information System (INIS)

    Kawahara, Toshio; Tabuchi, Norikazu; Arai, Takashi; Sato, Yoshikazu; Morimoto, Jun; Matsumura, Hideki

    2005-01-01

    We measured structure factors of hydrogenated amorphous Si by x-ray diffraction and analysed the obtained structures using a reverse Monte Carlo (RMC) technique. A small shoulder in the measured structure factor S(Q) was observed on the larger Q side of the first peak. The RMC results with an unconstrained model did not clearly show the small shoulder. Adding constraints for coordination numbers 2 and 3, the small shoulder was reproduced and the agreement with the experimental data became better. The ratio of the constrained coordination numbers was consistent with the ratio of Si-H and Si-H 2 bonds which was estimated by the Fourier transformed infrared spectra of the same sample. This shoulder and the oscillation of the corresponding pair distribution function g(r) at large r seem to be related to the low randomness of cat-CVD deposited a-Si:H

  19. Optimisation of electronic interface properties of a-Si:H/c-Si hetero-junction solar cells by wet-chemical surface pre-treatment

    Energy Technology Data Exchange (ETDEWEB)

    Angermann, H. [Hahn-Meitner-Institut, Abt. Siliziumphotovoltaik, Kekulestrasse 5, D-12489 Berlin (Germany)], E-mail: angermann@hmi.de; Korte, L.; Rappich, J.; Conrad, E.; Sieber, I.; Schmidt, M. [Hahn-Meitner-Institut, Abt. Siliziumphotovoltaik, Kekulestrasse 5, D-12489 Berlin (Germany); Huebener, K.; Hauschild, J. [Freie Universitaet Berlin, FB Physik, Arnimallee 14, 14195 Berlin (Germany)

    2008-08-30

    The relation between structural imperfections at structured silicon surfaces, energetic distribution of interface state densities, recombination loss at a-Si:H/c-Si interfaces and solar cell characteristics have been intensively investigated using non-destructive, surface sensitive techniques, surface photovoltage (SPV) and photoluminescence (PL) measurements, atomic force microscopy (AFM) and electron microscopy (SEM). Sequences of wet-chemical oxidation and etching steps were optimised with respect to the etching behaviour of Si(111) pyramids. Special wet-chemical smoothing and oxide removal procedures for structured substrates were developed, in order to reduce the preparation-induced surface micro-roughness and density of electronically active defects. H-termination and passivation by wet-chemical oxides were used to inhibit surface contamination and native oxidation during the technological process. We achieved significantly lower micro-roughness, densities of surface states D{sub it}(E) and recombination loss at a-Si:H/c-Si interfaces on wafers with randomly distributed pyramids, compared to conventional pre-treatments. For amorphous-crystalline hetero-junction solar cells (ZnO/a-Si:H/c-Si/BSF/Al), the c-Si surface becomes part of the a-Si:H/c-Si interface, whose recombination activity determines cell performance. With textured substrates, the smoothening procedure results in a significant increase of short circuit current, fill factor and efficiency.

  20. Optimisation of electronic interface properties of a-Si:H/c-Si hetero-junction solar cells by wet-chemical surface pre-treatment

    International Nuclear Information System (INIS)

    Angermann, H.; Korte, L.; Rappich, J.; Conrad, E.; Sieber, I.; Schmidt, M.; Huebener, K.; Hauschild, J.

    2008-01-01

    The relation between structural imperfections at structured silicon surfaces, energetic distribution of interface state densities, recombination loss at a-Si:H/c-Si interfaces and solar cell characteristics have been intensively investigated using non-destructive, surface sensitive techniques, surface photovoltage (SPV) and photoluminescence (PL) measurements, atomic force microscopy (AFM) and electron microscopy (SEM). Sequences of wet-chemical oxidation and etching steps were optimised with respect to the etching behaviour of Si(111) pyramids. Special wet-chemical smoothing and oxide removal procedures for structured substrates were developed, in order to reduce the preparation-induced surface micro-roughness and density of electronically active defects. H-termination and passivation by wet-chemical oxides were used to inhibit surface contamination and native oxidation during the technological process. We achieved significantly lower micro-roughness, densities of surface states D it (E) and recombination loss at a-Si:H/c-Si interfaces on wafers with randomly distributed pyramids, compared to conventional pre-treatments. For amorphous-crystalline hetero-junction solar cells (ZnO/a-Si:H/c-Si/BSF/Al), the c-Si surface becomes part of the a-Si:H/c-Si interface, whose recombination activity determines cell performance. With textured substrates, the smoothening procedure results in a significant increase of short circuit current, fill factor and efficiency

  1. Near-room temperature deposition of W and WO3 thin films by hydrogen atom assisted chemical vapor deposition

    International Nuclear Information System (INIS)

    Lee, W.W.; Reeves, R.R.

    1992-01-01

    A novel near-room temperatures CVD process has been developed using H-atoms reaction with WF 6 to produced tungsten and tungsten oxide films. The chemical, physical and electrical properties of these films were studied. Good adhesion and low resistivity of W films were measured. Conformal WO 3 films were obtained on columnar tungsten using a small amount of molecular oxygen in the gas stream. A reaction mechanism was evaluated on the basis of experimental results. The advantages of the method include deposition of adherent films in a plasma-free environment, near-room temperature, with a low level of impurity

  2. Electrical and optical properties of Cu–Cr–O thin films fabricated by chemical vapour deposition

    Energy Technology Data Exchange (ETDEWEB)

    Lunca Popa, P., E-mail: petru.luncapopa@list.lu; Crêpellière, J.; Leturcq, R.; Lenoble, D.

    2016-08-01

    We present electrical and optical properties of CuCrO{sub 2} thin films deposited by chemical vapour deposition, as well as the influence of depositions' parameters on these properties. Oxygen partial pressure and precursor's concentrations have the greatest influence on optical and electrical properties of the films. Values of conductivities ranging from 10{sup −4} to 10 S/cm were obtained using different deposition conditions. The conductivity is thermally activated with an activation energy ranging from 57 to 283 meV. Thermoelectric measurements confirm the p-type conduction, and demonstrate high carrier concentration typical for a degenerate semiconductor. The as-deposited films show a medium degree of crystallinity, a maximum optical transmission up to 80% in the visible range with a corresponding band gap around 3.2 eV. - Highlights: • CuCrO{sub 2} thin films deposited via a new innovative method - DLICVD. • Band gap and electrical conductivity can be tuned by controlling deposition parameters • Key process parameter is the metallic/oxygen atomic ratio involved in the process • Electrical conductivities values spanning 5 orders of magnitudes were obtained using different deposition parameters.

  3. Surface morphology and preferential orientation growth of TaC crystals formed by chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Xiong Xiang, E-mail: Xiong228@sina.co [State Key Lab for Powder Metallurgy, Central South University, Changsha 410083 (China); Chen Zhaoke; Huang Baiyun; Li Guodong [State Key Lab for Powder Metallurgy, Central South University, Changsha 410083 (China); Zheng Feng [School of Material Science and Engineering, Central South University, Changsha 410083 (China); Xiao Peng; Zhang Hongbo [State Key Lab for Powder Metallurgy, Central South University, Changsha 410083 (China)

    2009-04-02

    TaC film was deposited on (002) graphite sheet by isothermal chemical vapor deposition using TaCl{sub 5}-Ar-C{sub 3}H{sub 6} mixtures, with deposition temperature 1200 {sup o}C and pressure about 200 Pa. The influence of deposition position (or deposition rate) on preferential orientation and surface morphology of TaC crystals were investigated by X-ray diffraction and scanning electron microscopy methods. The deposits are TaC plus trace of C. The crystals are large individual columns with pyramidal-shape at deposition rate of 32.4-37.3 {mu}m/h, complex columnar at 37.3-45.6 {mu}m/h, lenticular-like at 45.6-54.6 {mu}m/h and cauliflower-like at 54.6-77.3 {mu}m/h, with <001>, near <001>, <110> and no clear preferential orientation, respectively. These results agree in part with the preditions of the Pangarov's model of the relationship between deposition rate and preferential growth orientation. The growth mechanism of TaC crystals in <001>, near <001>, <111> and no clear preferential orientation can be fairly explained by the growth parameter {alpha} with Van der Drift's model, deterioration model and Meakin model. Furthermore, a nucleation and coalescence model is also proposed to explain the formation mechanism of <110> lenticular-like crystals.

  4. Development of chemical and biological processes for production of bioethanol. Optimization of the wet oxidation process and characterization of products

    Energy Technology Data Exchange (ETDEWEB)

    Bjerre, A B; Skammelsen Schmidt, A

    1997-02-01

    The combination of the wet oxidation pretreatment process and alkaline hydrolysis was investigated in order to efficiently solubilize the hemicellulose, degrade the lignin, and open the solid crystalline cellulose structure of wheat straw lignocellulose without generating fermentation inhibitors. The effects of temperature, oxygen pressure, reaction time, and concentration of straw were evaluated. The degree of lignin degradation and hemicellulose solubilization increased with the reaction temperature and time. The optimum conditions were 15 minutes at 185 deg. C, producing 9.8 g/L hemicellulose. For quantification of the solubilized hemicellulose the best overall acid hydrolysis was obtained by treatment with 4 %w/v sulfuric acid for 10 minutes. The Aminex HPX-87H column was less sensitive towards impurities than the Aminex HPX-87P column. HPX-87H gave improved recovery and reproducibility, and was chosen for routine quantification of hydrolyzed hemicellulose sugars. The purity of the solid cellulose fraction also improved with higher temperature. The optimum condition for obtaining enzymatic convertible cellulose (90%) was 10 minutes at 170 deg. C using a high carbonate concentration. The hemicellulose yield and recovery were significantly reduced under these conditions indicating that a simultaneous optimal utilization of the hemicellulose and cellulose was difficult. The oxygen pressure and sodium carbonate concentration had little effect on the solubilization of hemicellulose, however, by combining wet oxidation with alkaline hydrolysis the formation of 2-furfural, a known microbial inhibitor, was minimal. Much more hemicellulose and lignin were solubilized from the straw by wet oxidation than by steaming(an alternative process). More cellulose was solubilized (and degraded) by steaming than by wet oxidation. Overall carbohydrates `losses` of 20.1% for steaming and 16.2% for wet oxidation were found. More 2-furfural was formed by steaming than by wet oxidation.

  5. Development of chemical and biological processes for production of bioethanol. Optimization of the wet oxidation process and characterization of products

    International Nuclear Information System (INIS)

    Bjerre, A.B.; Skammelsen Schmidt, A.

    1997-02-01

    The combination of the wet oxidation pretreatment process and alkaline hydrolysis was investigated in order to efficiently solubilize the hemicellulose, degrade the lignin, and open the solid crystalline cellulose structure of wheat straw lignocellulose without generating fermentation inhibitors. The effects of temperature, oxygen pressure, reaction time, and concentration of straw were evaluated. The degree of lignin degradation and hemicellulose solubilization increased with the reaction temperature and time. The optimum conditions were 15 minutes at 185 deg. C, producing 9.8 g/L hemicellulose. For quantification of the solubilized hemicellulose the best overall acid hydrolysis was obtained by treatment with 4 %w/v sulfuric acid for 10 minutes. The Aminex HPX-87H column was less sensitive towards impurities than the Aminex HPX-87P column. HPX-87H gave improved recovery and reproducibility, and was chosen for routine quantification of hydrolyzed hemicellulose sugars. The purity of the solid cellulose fraction also improved with higher temperature. The optimum condition for obtaining enzymatic convertible cellulose (90%) was 10 minutes at 170 deg. C using a high carbonate concentration. The hemicellulose yield and recovery were significantly reduced under these conditions indicating that a simultaneous optimal utilization of the hemicellulose and cellulose was difficult. The oxygen pressure and sodium carbonate concentration had little effect on the solubilization of hemicellulose, however, by combining wet oxidation with alkaline hydrolysis the formation of 2-furfural, a known microbial inhibitor, was minimal. Much more hemicellulose and lignin were solubilized from the straw by wet oxidation than by steaming(an alternative process). More cellulose was solubilized (and degraded) by steaming than by wet oxidation. Overall carbohydrates 'losses' of 20.1% for steaming and 16.2% for wet oxidation were found. More 2-furfural was formed by steaming than by wet oxidation

  6. Chemical solution deposition of CaCu3Ti4O12 thin film

    Indian Academy of Sciences (India)

    Administrator

    CaCu3Ti4O12; thin film; chemical solution deposition; dielectric properties. 1. Introduction. The CaCu3Ti4O12. (CCTO) compound has recently attracted considerable ... and Kelvin probe force microscopy (Chung et al 2004). Intrinsic .... SEM images of CCTO thin films as a function of sintering temperature. silicon based ...

  7. Self-catalytic growth of tin oxide nanowires by chemical vapor deposition process

    CSIR Research Space (South Africa)

    Thabethe, BS

    2013-01-01

    Full Text Available The authors report on the synthesis of tin oxide (SnO(sub2)) nanowires by a chemical vapor deposition (CVD) process. Commercially bought SnO nanopowders were vaporized at 1050°C for 30 minutes with argon gas continuously passing through the system...

  8. Prospects of chemically deposited CoS-CU2S coatings for solar ...

    African Journals Online (AJOL)

    The thin films of Cu2S deposited on CoS-precoated glass substrates from chemical baths and annealed at 100oC were found to have desirable solar control characteristics superior to commercial tinted glass and magnetron sputtered multilayer metallic solar control coatings. These include: transmission spectra in the ...

  9. Vaporization of a mixed precursors in chemical vapor deposition for YBCO films

    Science.gov (United States)

    Zhou, Gang; Meng, Guangyao; Schneider, Roger L.; Sarma, Bimal K.; Levy, Moises

    1995-01-01

    Single phase YBa2Cu3O7-delta thin films with T(c) values around 90 K are readily obtained by using a single source chemical vapor deposition technique with a normal precursor mass transport. The quality of the films is controlled by adjusting the carrier gas flow rate and the precursor feed rate.

  10. Controllable chemical vapor deposition of large area uniform nanocrystalline graphene directly on silicon dioxide

    DEFF Research Database (Denmark)

    Sun, Jie; Lindvall, Niclas; Cole, Matthew T.

    2012-01-01

    Metal-catalyst-free chemical vapor deposition (CVD) of large area uniform nanocrystalline graphene on oxidized silicon substrates is demonstrated. The material grows slowly, allowing for thickness control down to monolayer graphene. The as-grown thin films are continuous with no observable pinholes...

  11. Layer-dependent supercapacitance of graphene films grown by chemical vapor deposition on nickel foam

    KAUST Repository

    Chen, Wei; Fan, Zhongli; Zeng, Gaofeng; Lai, Zhiping

    2013-01-01

    High-quality, large-area graphene films with few layers are synthesized on commercial nickel foams under optimal chemical vapor deposition conditions. The number of graphene layers is adjusted by varying the rate of the cooling process. It is found

  12. Influence of the catalyst type on the growth of carbon nanotubes via methane chemical vapor deposition

    NARCIS (Netherlands)

    Jodin, Lucie; Dupuis, Anne-Claire; Rouvière, Emmanuelle; Reiss, Peter

    2006-01-01

    The preparation of the catalyst is one of the key parameters which governs the quality of carbon nanotubes (CNTs) grown by catalyzed chemical vapor deposition (CVD). We investigated the influence of three different procedures of catalyst preparation on the type and diameter of CNTs formed under

  13. ArF Laser -Induced Chemical Vapour Deposition of Polythiene Films from Carbon Disulfide

    Czech Academy of Sciences Publication Activity Database

    Tomovska, R.; Bastl, Zdeněk; Vorlíček, Vladimír; Vacek, Karel; Šubrt, Jan; Plzák, Zbyněk; Pola, Josef

    2003-01-01

    Roč. 107, č. 36 (2003), s. 9793-9801 ISSN 1089-5647 R&D Projects: GA MŠk ME 612 Institutional research plan: CEZ:AV0Z4032918; CEZ:AV0Z4040901 Keywords : laser photolysis * ArF * chemical vapour deposition Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.679, year: 2003

  14. The study of metal sulphide nanomaterials obtained by chemical bath deposition and hot-injection technique

    Science.gov (United States)

    Maraeva, E. V.; Alexandrova, O. A.; Forostyanaya, N. A.; Levitskiy, V. S.; Mazing, D. S.; Maskaeva, L. N.; Markov, V. Ph; Moshnikov, V. A.; Shupta, A. A.; Spivak, Yu M.; Tulenin, S. S.

    2015-11-01

    In this study lead sulphide - cadmium sulphide based layers were obtained through chemical deposition of water solutions and cadmium sulphide quantum dots were formed through hot-injection technique. The article discusses the results of surface investigations with the use of atomic force microscopy, Raman spectroscopy and photoluminescence measurements.

  15. The study of metal sulphide nanomaterials obtained by chemical bath deposition and hot-injection technique

    International Nuclear Information System (INIS)

    Maraeva, E V; Alexandrova, O A; Levitskiy, V S; Mazing, D S; Moshnikov, V A; Shupta, A A; Spivak, Yu M; Forostyanaya, N A; Maskaeva, L N; Markov, V Ph; Tulenin, S S

    2015-01-01

    In this study lead sulphide – cadmium sulphide based layers were obtained through chemical deposition of water solutions and cadmium sulphide quantum dots were formed through hot-injection technique. The article discusses the results of surface investigations with the use of atomic force microscopy, Raman spectroscopy and photoluminescence measurements. (paper)

  16. Influence of krypton atoms on the structure of hydrogenated amorphous carbon deposited by plasma enhanced chemical vapor deposition

    Science.gov (United States)

    Oliveira, M. H.; Viana, G. A.; de Lima, M. M.; Cros, A.; Cantarero, A.; Marques, F. C.

    2010-12-01

    Hydrogenated amorphous carbon (a-C:H) films were prepared by plasma enhanced chemical vapor deposition using methane (CH4) plus krypton (Kr) mixed atmosphere. The depositions were performed as function of the bias voltage and krypton partial pressure. The goal of this work was to study the influence of krypton gas on the physical properties of a-C:H films deposited on the cathode electrode. Krypton concentration up to 1.6 at. %, determined by Rutherford Back-Scattering, was obtained at high Kr partial pressure and bias of -120 V. The structure of the films was analyzed by means of optical transmission spectroscopy, multi-wavelength Raman scattering and Fourier Transform Infrared spectroscopy. It was verified that the structure of the films remains unchanged up to a concentration of Kr of about 1.0 at. %. A slight graphitization of the films occurs for higher concentration. The observed variation in the film structure, optical band gap, stress, and hydrogen concentration were associated mainly with the subplantation process of hydrocarbons radicals, rather than the krypton ion energy.

  17. Influence of krypton atoms on the structure of hydrogenated amorphous carbon deposited by plasma enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    Oliveira, M. H. Jr.; Viana, G. A.; Marques, F. C.; Lima, M. M. Jr. de; Cros, A.; Cantarero, A.

    2010-01-01

    Hydrogenated amorphous carbon (a-C:H) films were prepared by plasma enhanced chemical vapor deposition using methane (CH 4 ) plus krypton (Kr) mixed atmosphere. The depositions were performed as function of the bias voltage and krypton partial pressure. The goal of this work was to study the influence of krypton gas on the physical properties of a-C:H films deposited on the cathode electrode. Krypton concentration up to 1.6 at. %, determined by Rutherford Back-Scattering, was obtained at high Kr partial pressure and bias of -120 V. The structure of the films was analyzed by means of optical transmission spectroscopy, multi-wavelength Raman scattering and Fourier Transform Infrared spectroscopy. It was verified that the structure of the films remains unchanged up to a concentration of Kr of about 1.0 at. %. A slight graphitization of the films occurs for higher concentration. The observed variation in the film structure, optical band gap, stress, and hydrogen concentration were associated mainly with the subplantation process of hydrocarbons radicals, rather than the krypton ion energy.

  18. Annealing and deposition effects of the chemical composition of silicon rich nitride

    DEFF Research Database (Denmark)

    Andersen, Karin Nordström; Svendsen, Winnie Edith; Stimpel-Lindner, T.

    2005-01-01

    Silicon-rich nitride, deposited by LPCVD, is a low stress amorphous material with a high refractive index. After deposition the silicon-rich nitride thin film is annealed at temperatures above 1100 oC to break N-H bonds, which have absorption peaks in the wavelength band important for optical...... in optical waveguides. This means that the annealing temperature must be high enough to break the N-H bonds, but no so high as to produce clusters. Therefore, the process window for an annealing step lies between 1100 and 1150 oC. The chemical composition of amorphous silicon-rich nitride has been...... investigated by Rutherford back scattering (RBS) and X-ray photoelectron spectroscopy (XPS). The influence of deposition parameters and annealing temperatures on the stoichiometry and the chemical bonds will be discussed. The origin of the clusters has been found to be silicon due to severe silicon out...

  19. Self-cleaning and surface chemical reactions during hafnium dioxide atomic layer deposition on indium arsenide.

    Science.gov (United States)

    Timm, Rainer; Head, Ashley R; Yngman, Sofie; Knutsson, Johan V; Hjort, Martin; McKibbin, Sarah R; Troian, Andrea; Persson, Olof; Urpelainen, Samuli; Knudsen, Jan; Schnadt, Joachim; Mikkelsen, Anders

    2018-04-12

    Atomic layer deposition (ALD) enables the ultrathin high-quality oxide layers that are central to all modern metal-oxide-semiconductor circuits. Crucial to achieving superior device performance are the chemical reactions during the first deposition cycle, which could ultimately result in atomic-scale perfection of the semiconductor-oxide interface. Here, we directly observe the chemical reactions at the surface during the first cycle of hafnium dioxide deposition on indium arsenide under realistic synthesis conditions using photoelectron spectroscopy. We find that the widely used ligand exchange model of the ALD process for the removal of native oxide on the semiconductor and the simultaneous formation of the first hafnium dioxide layer must be significantly revised. Our study provides substantial evidence that the efficiency of the self-cleaning process and the quality of the resulting semiconductor-oxide interface can be controlled by the molecular adsorption process of the ALD precursors, rather than the subsequent oxide formation.

  20. Influences of in-cloud aerosol scavenging parameterizations on aerosol concentrations and wet deposition in ECHAM5-HAM

    Directory of Open Access Journals (Sweden)

    B. Croft

    2010-02-01

    Full Text Available A diagnostic cloud nucleation scavenging scheme, which determines stratiform cloud scavenging ratios for both aerosol mass and number distributions, based on cloud droplet, and ice crystal number concentrations, is introduced into the ECHAM5-HAM global climate model. This scheme is coupled with a size-dependent in-cloud impaction scavenging parameterization for both cloud droplet-aerosol, and ice crystal-aerosol collisions. The aerosol mass scavenged in stratiform clouds is found to be primarily (>90% scavenged by cloud nucleation processes for all aerosol species, except for dust (50%. The aerosol number scavenged is primarily (>90% attributed to impaction. 99% of this impaction scavenging occurs in clouds with temperatures less than 273 K. Sensitivity studies are presented, which compare aerosol concentrations, burdens, and deposition for a variety of in-cloud scavenging approaches: prescribed fractions, a more computationally expensive prognostic aerosol cloud processing treatment, and the new diagnostic scheme, also with modified assumptions about in-cloud impaction and nucleation scavenging. Our results show that while uncertainties in the representation of in-cloud scavenging processes can lead to differences in the range of 20–30% for the predicted annual, global mean aerosol mass burdens, and near to 50% for accumulation mode aerosol number burden, the differences in predicted aerosol mass concentrations can be up to one order of magnitude, particularly for regions of the middle troposphere with temperatures below 273 K where mixed and ice phase clouds exist. Different parameterizations for impaction scavenging changed the predicted global, annual mean number removal attributed to ice clouds by seven-fold, and the global, annual dust mass removal attributed to impaction by two orders of magnitude. Closer agreement with observations of black carbon profiles from aircraft (increases near to one order of magnitude for mixed phase clouds

  1. Microstructural and conductivity changes induced by annealing of ZnO:B thin films deposited by chemical vapour deposition

    International Nuclear Information System (INIS)

    David, C; Girardeau, T; Paumier, F; Eyidi, D; Guerin, P; Marteau, M; Lacroix, B; Papathanasiou, N; Tinkham, B P

    2011-01-01

    Zinc oxide (ZnO) thin films have attracted much attention in recent years due to progress in crystal growth for a large variety of technological applications including optoelectronics and transparent electrodes in solar cells. Boron (B)-doped ZnO thin films are deposited by low pressure chemical vapour deposition (LPCVD) on Si(100). These films exhibit a strong (002) texture with a pyramidal grain structure. The ZnO films were annealed after growth; the annealing temperature and the atmosphere appear to strongly impact the layer conductivity. This work will first present the modification of the physical properties (carrier concentration, mobility) extracted from the simulation of layer reflection in the infrared range. At low annealing temperatures the mobility increases slightly before decreasing drastically above a temperature close to 250 deg. C. The chemical and structural evolution (XPS, x-ray diffraction) of the films was also studied to identify the relationship between microstructural modifications and the variations observed in the film conductivity. An in situ XRD study during annealing has been performed under air and low pressure conditions. As observed for electrical properties, the microstructural modifications shift to higher temperatures for vacuum annealing.

  2. Co3O4 protective coatings prepared by Pulsed Injection Metal Organic Chemical Vapour Deposition

    DEFF Research Database (Denmark)

    Burriel, M.; Garcia, G.; Santiso, J.

    2005-01-01

    of deposition temperature. Pure Co3O4 spinel structure was found for deposition temperatures ranging from 360 to 540 degreesC. The optimum experimental parameters to prepare dense layers with a high growth rate were determined and used to prepare corrosion protective coatings for Fe-22Cr metallic interconnects......Cobalt oxide films were grown by Pulsed Injection Metal Organic Chemical Vapour Deposition (PI-MOCVD) using Co(acac)(3) (acac=acetylacetonate) precursor dissolved in toluene. The structure, morphology and growth rate of the layers deposited on silicon substrates were studied as a function......, to be used in Intermediate Temperature Solid Oxide Fuel Cells. (C) 2004 Elsevier B.V. All rights reserved....

  3. Zinc Sulfide Buffer Layer for CIGS Solar Cells Prepared by Chemical Bath Deposition

    Directory of Open Access Journals (Sweden)

    Rui-Wei You

    2016-11-01

    Full Text Available In this study, ZnS thin films were successfully synthesized by chemical bath deposition (CBD with starting materials of NH2-NH2, SC(NH22, and ZnSO4‧7H2O. ZnS thin films were deposited with different time on glass substrates by CBD at 80oC and pH=9. Based on X-ray diffraction (XRD patterns, it is found that the ZnS thin films exhibit cubic polycrystalline phase. It was found that the optimum deposition time is 90 min for preparing ZnS thin film that is suitable as buffer layer for CuIn1-xGaxSe2 solar cells. The thin film deposited for 90 min has high transmittance up to 80% in the spectra range from 350 nm to 800 nm, and the optical band gap is about 3.59 eV.

  4. One-step microwave plasma enhanced chemical vapor deposition (MW-PECVD) for transparent superhydrophobic surface

    Science.gov (United States)

    Thongrom, Sukrit; Tirawanichakul, Yutthana; Munsit, Nantakan; Deangngam, Chalongrat

    2018-02-01

    We demonstrate a rapid and environmental friendly fabrication technique to produce optically clear superhydrophobic surfaces using poly (dimethylsiloxane) (PDMS) as a sole coating material. The inert PDMS chain is transformed into a 3-D irregular solid network through microwave plasma enhanced chemical vapor deposition (MW-PECVD) process. Thanks to high electron density in the microwave-activated plasma, coating can be done in just a single step with rapid deposition rate, typically much shorter than 10 s. Deposited layers show excellent superhydrophobic properties with water contact angles of ∼170° and roll-off angles as small as ∼3°. The plasma-deposited films can be ultrathin with thicknesses under 400 nm, greatly diminishing the optical loss. Moreover, with appropriate coating conditions, the coating layer can even enhance the transmission over the entire visible spectrum due to a partial anti-reflection effect.

  5. Investigation of CdS/InP heterojunction prepared by chemical bath deposition

    International Nuclear Information System (INIS)

    Rakovics, V.; Horvath, Zs.J.; Horvath, Zs.E.; Barsony, I.; Frigeri, C.; Besagni, T.

    2007-01-01

    CdS thin films have been deposited on InP and glass substrates using the chemical bath deposition technique. Baths containing CdSO 4 , thiourea, and NH 3 were used. The temperature of the deposition process was 65 C and the duration of deposition varied between 20 and 160 minutes. The properties of the CdS/InP heterojunction were investigated by TEM, EDS and X-ray diffraction. TEM pictures, EDS and X-ray rocking curves indicate the formation of a β-In 2 S 3 transition layer at the InP-CdS interface, which may reduce the lattice mismatch between InP and CdS. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. Textured indium tin oxide thin films by chemical solution deposition and rapid thermal processing

    International Nuclear Information System (INIS)

    Mottern, Matthew L.; Tyholdt, Frode; Ulyashin, Alexander; Helvoort, Antonius T.J. van; Verweij, Henk; Bredesen, Rune

    2007-01-01

    The microstructure of state-of-the-art chemical solution deposited indium tin oxide thin films typically consists of small randomly oriented grains, high porosity and poor homogeneity. The present study demonstrates how the thin film microstructure can be improved significantly by tailoring the precursor solutions and deposition conditions to be kinetically and thermodynamically favorable for generation of homogeneous textured thin films. This is explained by the occurrence of a single heterogeneous nucleation mechanism. The as-deposited thin films, crystallized at 800 deg. C, have a high apparent density, based on a refractive index of ∼ 1.98 determined by single wavelength ellipsometry at 633 nm. The microstructure of the films consists of columnar grains with preferred orientation as determined by X-ray diffraction and transmission electron microscopy. The resistivity, measured by the four point probe method, is ∼ 2 x 10 -3 Ω cm prior to post-deposition treatments

  7. Plasma Assisted Chemical Vapour Deposition – Technological Design Of Functional Coatings

    Directory of Open Access Journals (Sweden)

    Januś M.

    2015-06-01

    Full Text Available Plasma Assisted Chemical Vapour Deposition (PA CVD method allows to deposit of homogeneous, well-adhesive coatings at lower temperature on different substrates. Plasmochemical treatment significantly impacts on physicochemical parameters of modified surfaces. In this study we present the overview of the possibilities of plasma processes for the deposition of diamond-like carbon coatings doped Si and/or N atoms on the Ti Grade2, aluminum-zinc alloy and polyetherketone substrate. Depending on the type of modified substrate had improved the corrosion properties including biocompatibility of titanium surface, increase of surface hardness with deposition of good adhesion and fine-grained coatings (in the case of Al-Zn alloy and improving of the wear resistance (in the case of PEEK substrate.

  8. Importance of deposit information in the design and execution of steam generator chemical cleaning

    International Nuclear Information System (INIS)

    Flores, O.; Remark, J.

    1997-01-01

    During the planning stages of the chemical cleaning of the San Onofre Nuclear Generating Station (SONGS) units 2 and 3 steam generators, it was determined that an understanding of the steam generator deposit loading and composition was essential to the design and success of the project. It was also determined that qualification testing, preferably with actual deposits from the SONGS steam generators, was also essential. SONGS units 2 and 3 have Combustion Engineering (CE)-designed pressurized water reactors. Each unit has two CE model 3410 steam generators. Each steam generator has 9350 alloy 600 tubes with 1.9-cm (3/4 in.) outside diameter. Unit 2 began commercial operation in 1983, and unit 3, in 1984. The purpose of this technical paper is to explain the effort and methodology for deposit composition, characterization, and quantification. In addition, the deposit qualification testing and design of the cleaning are discussed

  9. Chemical processes, desired and undesired, in the selective chemical vapor deposition of tungsten

    International Nuclear Information System (INIS)

    Wilson, R.H.

    1988-01-01

    The deposition of tungsten by the hydrogen reduction of tungsten hexafluoride is discussed in the context of its application in integrated circuits. The overall reaction is relatively simple; however, numerous competing reactions and their implications are discussed. In addition, those areas which could benefit from further investigation are identified

  10. Scavenging ratios, wet deposition, and in-cloud oxidation: An application to the oxides of sulphur and nitrogen

    International Nuclear Information System (INIS)

    Barrie, L.A.

    1985-01-01

    With special regard to the class of substances in precipitation that potentially originate from both gaseous and particulate precursors, the process of precipitation scavenging is discussed. A model relating daily average ground level scavenging ratios (W) to nucleation scavenging and in-cloud chemical transformation is introduced and is used as guidance in the regression analysis of 3 years of SO 4 = and NO 3 - scavenging-ratio observations made at six locations in eastern Canada. It was found that W of SO 4 = -, NO 3 = -, and SO 4 = -bearing particles is inversely proportional to the one-third power of the precipitation amount in the event. The best regression model explained 41% of the variance in log W for SO 4 = . It included the effects of location, precipitation amount, precipitation type, and in-cloud SO 2 oxidation. The last effect accounted for 50% of the variance explained. The analysis predicts that, on average, in-cloud SO 2 oxidation accounts for 42--79% of the SO 4 = observed in rain and with the exception of one site, less than 20% of the SO 4 = observed in snow. These results are consistent with a mechanism of SO 2 oxidation involving photochemically produced H 2 O 2 . A similar analysis for NO 3 - supports the hypothesis that throughout the year much of the NO 3 - in precipitation originates from in-cloud NO 2 oxidation. It suggests that, depending on location, oxidation of 0.5--1.2 ppbv of NO 2 is sufficient to explain observations. One possible mechanism of oxidation is the reaction with O 3 to form NO 3 and hence soluble N 2 O 5

  11. Synthesis of carbon nanotubes using the cobalt nanocatalyst by thermal chemical vapor deposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Madani, S.S. [Department of Chemistry, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Zare, K. [Department of Chemistry, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Department of Chemistry, Shahid Beheshti University, Tehran (Iran, Islamic Republic of); Ghoranneviss, M. [Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Salar Elahi, A., E-mail: Salari_phy@yahoo.com [Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of)

    2015-11-05

    The three main synthesis methods of Carbon nanotubes (CNTs) are the arc discharge, the laser ablation and the chemical vapour deposition (CVD) with a special regard to the latter one. CNTs were produced on a silicon wafer by Thermal Chemical Vapor Deposition (TCVD) using acetylene as a carbon source, cobalt as a catalyst and ammonia as a reactive gas. The DC-sputtering system was used to prepare cobalt thin films on Si substrates. A series of experiments was carried out to investigate the effects of reaction temperature and deposition time on the synthesis of the nanotubes. The deposition time was selected as 15 and 25 min for all growth temperatures. Energy Dispersive X-ray (EDX) measurements were used to investigate the elemental composition of the Co nanocatalyst deposited on Si substrates. Atomic Force Microscopy (AFM) was used to characterize the surface topography of the Co nanocatalyst deposited on Si substrates. The as-grown CNTs were characterized under Field Emission Scanning Electron Microscopy (FESEM) to study the morphological properties of CNTs. Also, the grown CNTs have been investigated by High Resolution Transmission Electron Microscopy (HRTEM) and Raman spectroscopy. The results demonstrated that increasing the temperature leads to increasing the diameter of CNTs. The ideal reaction temperature was 850 °C and the deposition time was 15 min. - Graphical abstract: FESEM images of CNTs grown on the cobalt catalyst at growth temperatures of (a) 850 °C, (b) 900 °C, (c) 950 °C and (d) 1000 °C during the deposition time of 15 min. - Highlights: • Carbon nanotubes (CNTs) were produced on a silicon wafer by TCVD technique. • EDX and AFM were used to investigate the elemental composition and surface topography. • FESEM was used to study the morphological properties of CNTs. • The grown CNTs have been investigated by HRTEM and Raman spectroscopy.

  12. On the Growth and Microstructure of Carbon Nanotubes Grown by Thermal Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    Handuja Sangeeta

    2010-01-01

    Full Text Available Abstract Carbon nanotubes (CNTs were deposited on various substrates namely untreated silicon and quartz, Fe-deposited silicon and quartz, HF-treated silicon, silicon nitride-deposited silicon, copper foil, and stainless steel mesh using thermal chemical vapor deposition technique. The optimum parameters for the growth and the microstructure of the synthesized CNTs on these substrates are described. The results show that the growth of CNTs is strongly influenced by the substrate used. Vertically aligned multi-walled CNTs were found on quartz, Fe-deposited silicon and quartz, untreated silicon, and on silicon nitride-deposited silicon substrates. On the other hand, spaghetti-type growth was observed on stainless steel mesh, and no CNT growth was observed on HF-treated silicon and copper. Silicon nitride-deposited silicon substrate proved to be a promising substrate for long vertically aligned CNTs of length 110–130 μm. We present a possible growth mechanism for vertically aligned and spaghetti-type growth of CNTs based on these results.

  13. Limitations of patterning thin films by shadow mask high vacuum chemical vapor deposition

    International Nuclear Information System (INIS)

    Reinke, Michael; Kuzminykh, Yury; Hoffmann, Patrik

    2014-01-01

    A key factor in engineering integrated devices such as electro-optic switches or waveguides is the patterning of high quality crystalline thin films into specific geometries. In this contribution high vacuum chemical vapor deposition (HV-CVD) was employed to grow titanium dioxide (TiO 2 ) patterns onto silicon. The directed nature of precursor transport – which originates from the high vacuum environment during the process – allows shading certain regions on the substrate by shadow masks and thus depositing patterned thin films. While the use of such masks is an emerging field in stencil or shadow mask lithography, their use for structuring thin films within HV-CVD has not been reported so far. The advantage of the employed technique is the precise control of lateral spacing and of the distance between shading mask and substrate surface which is achieved by manufacturing them directly on the substrate. As precursor transport takes place in the molecular flow regime, the precursor impinging rates (and therefore the film growth rates) on the surface can be simulated as function of the reactor and shading mask geometry using a comparatively simple mathematical model. In the current contribution such a mathematical model, which predicts impinging rates on plain or shadow mask structured substrates, is presented. Its validity is confirmed by TiO 2 -deposition on plain silicon substrates (450 °C) using titanium tetra isopropoxide as precursor. Limitations of the patterning process are investigated by the deposition of TiO 2 on structured substrates and subsequent shadow mask lift-off. The geometry of the deposits is according to the mathematical model. Shading effects due to the growing film enables to fabricate deposits with predetermined variations in topography and non-flat top deposits which are complicated to obtain by classical clean room processes. As a result of the enhanced residual pressure of decomposition products and titanium precursors and the

  14. A study of the performance and properties of diamond like carbon (DLC) coatings deposited by plasma chemical vapor deposition (CVD) for two stroke engine components

    Energy Technology Data Exchange (ETDEWEB)

    Tither, D. [BEP Grinding Ltd., Manchester (United Kingdom); Ahmed, W.; Sarwar, M.; Penlington, R. [Univ. of Northumbria, Newcastle-upon-Tyne (United Kingdom)

    1995-12-31

    Chemical vapor deposition (CVD) using microwave and RF plasma is arguably the most successful technique for depositing diamond and diamond like carbon (DLC) films for various engineering applications. However, the difficulties of depositing diamond are nearly as extreme as it`s unique combination of physical, chemical and electrical properties. In this paper, the modified low temperature plasma enhanced CVD system is described. The main focus of this paper will be work related to deposition of DLC on metal matrix composite materials (MMCs) for application in two-stroke engine components and results will be presented from SEM, mechanical testing and composition analysis studies. The authors have demonstrated the feasibility of depositing DLC on MMCs for the first time using a vacuum deposition process.

  15. Surface-driven, one-step chemical vapor deposition of γ-Al{sub 4}Cu{sub 9} complex metallic alloy film

    Energy Technology Data Exchange (ETDEWEB)

    Prud’homme, Nathalie [CIRIMAT, Université de Toulouse - CNRS, 4 allée Emile Monso, BP-44362, 31432 Toulouse Cedex 4 (France); Université Paris-Sud 11, LEMHE/ICMMO, Bat 410, 91405 Orsay Cedex (France); Duguet, Thomas, E-mail: thomas.duguet@ensiacet.fr [CIRIMAT, Université de Toulouse - CNRS, 4 allée Emile Monso, BP-44362, 31432 Toulouse Cedex 4 (France); Samélor, Diane; Senocq, François; Vahlas, Constantin [CIRIMAT, Université de Toulouse - CNRS, 4 allée Emile Monso, BP-44362, 31432 Toulouse Cedex 4 (France)

    2013-10-15

    The present paper is a paradigm for the one-step formation of complex intermetallic coatings by chemical vapor deposition. It genuinely addresses the challenge of depositing an intermetallic coating with comparable contents of Cu and Al. Depending on processing conditions, a pure γ-Al{sub 4}Cu{sub 9} and multi-phase Al-Cu films are grown with wetting properties of the former being similar to its bulk counterpart. The deposition process and its parametric investigation are detailed. Two metalorganic precursors are used taking into account their transport and chemical properties, and deposition temperature ranges. On line and ex situ characterizations enlighten the competition which occurs at the growing surface between molecular fragments, and which limits growth rates. Notably, introducing a partial pressure of hydrogen gas during deposition reduces Al growth rate from dimethylethylamine alane (DMEAA), by displacing the hydrogen desorption equilibrium. This Al partial growth rate decrease is not sufficient to achieve a Cu/Al atomic ratio that is high enough for the formation of intermetallics with close Al and Cu compositions. A fivefold increase of the flux of the gaseous copper(I) cyclopentadienyl triethylphosphine CpCuPEt{sub 3}, whereas the DMEAA flux remains constant, results in the targeted Al/Cu atomic ratio equal to 44/56. Nevertheless, the global growth rate is rendered extremely low by the deposition inhibition caused by a massive phosphine adsorption (-PEt{sub 3}). Despite these limitations, the results pave the way towards the conformal coating of complex surface geometries by such intermetallic compounds.

  16. Physical and chemical properties of deposited airborne particulates over the Arabian Red Sea coastal plain

    KAUST Repository

    Engelbrecht, Johann

    2017-09-27

    Mineral dust is the most abundant aerosol, having a profound impact on the global energy budget. This research continues our previous studies performed on surface soils in the Arabian Peninsula, focusing on the mineralogical, physical and chemical composition of dust deposits from the atmosphere at the Arabian Red Sea coast. For this purpose, aerosols deposited from the atmosphere are collected during 2015 at six sites on the campus of the King Abdullah University of Science and Technology (KAUST) situated on the Red Sea coastal plain of Saudi Arabia and subjected to the same chemical and mineralogical analysis we conducted on soil samples. Frisbee deposition samplers with foam inserts were used to collect dust and other deposits, for the period December 2014 to December 2015. The average deposition rate measured at KAUST for this period was 14 g m−2 per month, with lowest values in winter and increased deposition rates in August to October. The particle size distributions provide assessments of  < 10 and  < 2.5 µm dust deposition rates, and it is suggested that these represent proxies for PM10 (coarse) and PM2. 5 (fine) particle size fractions in the dust deposits. X-ray diffraction (XRD) analysis of a subset of samples confirms variable amounts of quartz, feldspars, micas, and halite, with lesser amounts of gypsum, calcite, dolomite, hematite, and amphibole. Freeze-dried samples were re-suspended onto the Teflon® filters for elemental analysis by X-ray fluorescence (XRF), while splits from each sample were analyzed for water-soluble cations and anions by ion chromatography. The dust deposits along the Red Sea coast are considered to be a mixture of dust emissions from local soils and soils imported from distal dust sources. Airborne mineral concentrations are greatest at or close to dust sources, compared to those through medium- and long-range transport. It is not possible to identify the exact origin of deposition samples from the

  17. Effect of deposition temperature on the structural, morphological and optical band gap of lead selenide thin films synthesized by chemical bath deposition method

    Energy Technology Data Exchange (ETDEWEB)

    Hone, Fekadu Gashaw, E-mail: fekeye@gmail.com [Hawassa University, Department of Physics, Hawassa (Ethiopia); Ampong, Francis Kofi [Kwame Nkrumah University of Science and Technology, Department of Physics, Kumasi (Ghana)

    2016-11-01

    Lead selenide (PbSe) nanocrystalline thin films have been deposited on silica glass substrates by the chemical bath deposition technique. The samples were deposited at the bath temperatures of 60, 75 and 90 °C respectively and characterized by a variety of techniques. The XRD results revealed that the PbSe thin film deposited at 60 °C was amorphous in nature. Films deposited at higher temperatures exhibited sharp and intense diffraction peaks, indicating an improvement in crystallinety. The deposition temperature also had a strong influence on the preferred orientation of the crystallites as well as other structural parameters such as microstrain and dislocation density. From the SEM study it was observed that film deposited at 90 °C had well defined crystallites, uniformly distributed over the entire surface of the substrate. The EDAX study confirmed that the samples deposited at the higher temperature had a better stoichiometric ratio. The optical band gap varied from 2.26 eV to 1.13 eV with increasing deposition temperature. - Highlights: • The crystallinety of the films improved as the deposition temperature increased. • The deposition temperature strongly influenced the preferred orientations. • Microstrain and dislocation density are decreased linearly with deposition temperature. • Band gap decreased from 2.26 eV to 1.13 eV as the deposition temperature increased.

  18. Dissolved organic carbon in the precipitation of Seoul, Korea: Implications for global wet depositional flux of fossil-fuel derived organic carbon

    Science.gov (United States)

    Yan, Ge; Kim, Guebuem

    2012-11-01

    Precipitation was sampled in Seoul over a one-year period from 2009 to 2010 to investigate the sources and fluxes of atmospheric dissolved organic carbon (DOC). The concentrations of DOC varied from 15 μM to 780 μM, with a volume-weighted average of 94 μM. On the basis of correlation analysis using the commonly acknowledged tracers, such as vanadium, the combustion of fossil-fuels was recognized to be the dominant source. With the aid of air mass backward trajectory analyses, we concluded that the primary fraction of DOC in our precipitation samples originated locally in Korea, albeit the frequent long-range transport from eastern and northeastern China might contribute substantially. In light of the relatively invariant organic carbon to sulfur mass ratios in precipitation over Seoul and other urban regions around the world, the global magnitude of wet depositional DOC originating from fossil-fuels was calculated to be 36 ± 10 Tg C yr-1. Our study further underscores the potentially significant environmental impacts that might be brought about by this anthropogenically derived component of organic carbon in the atmosphere.

  19. Assessing the Roles of Iron, Macronutrients and Wet deposition in Controlling Phytoplankton Growth in Seasonally Oligotrophic Waters of the Mid-Atlantic Bight

    Science.gov (United States)

    Sedwick, P.; Mulholland, M. R.; Najjar, R.; Bernhardt, P. W.; Price, L. M.; Sohst, B. M.; Sookhdeo, C.; Widner, B.

    2016-02-01

    The role of iron supply in regulating phytoplankton production in high-nutrient, low-chlorophyll ocean regions has been well established. Less clear, however, is the importance of iron for phytoplankton processes in other oceanic settings, such as coastal and oligotrophic waters, where differential changes in the supply and removal of dissolved iron (dFe) can result in limitation or co-limitation of growth due to iron deficiency. One such region of interest is the Mid-Atlantic Bight (MAB), where previous field experiments have provided some evidence of co-limitation of algal growth by nitrogen and iron. In summer 2014 we conducted field sampling and shipboard experiments to assess the role of iron and macronutrient availability in controlling primary production in seasonally oligotrophic waters over the MAB continental slope, with a focus on the the impacts of wet deposition. Our results indicate that nitrogen was the proximate limiting nutrient, with a secondary limitation imposed by availability of phosphorus; we found no evidence for a deficiency in dFe, which was present at concentrations in the range 0.3-0.9 nM. Phytoplankton growth was clearly stimulated by the addition of natural rainwater, suggesting that summer rain events stimulate primary production in the MAB by contributing new nitrogen (primarily as ammonium) and phosphorus, whilst maintaining iron-replete conditions.

  20. High-throughput combinatorial chemical bath deposition: The case of doping Cu (In, Ga) Se film with antimony

    Science.gov (United States)

    Yan, Zongkai; Zhang, Xiaokun; Li, Guang; Cui, Yuxing; Jiang, Zhaolian; Liu, Wen; Peng, Zhi; Xiang, Yong

    2018-01-01

    The conventional methods for designing and preparing thin film based on wet process remain a challenge due to disadvantages such as time-consuming and ineffective, which hinders the development of novel materials. Herein, we present a high-throughput combinatorial technique for continuous thin film preparation relied on chemical bath deposition (CBD). The method is ideally used to prepare high-throughput combinatorial material library with low decomposition temperatures and high water- or oxygen-sensitivity at relatively high-temperature. To check this system, a Cu(In, Ga)Se (CIGS) thin films library doped with 0-19.04 at.% of antimony (Sb) was taken as an example to evaluate the regulation of varying Sb doping concentration on the grain growth, structure, morphology and electrical properties of CIGS thin film systemically. Combined with the Energy Dispersive Spectrometer (EDS), X-ray Photoelectron Spectroscopy (XPS), automated X-ray Diffraction (XRD) for rapid screening and Localized Electrochemical Impedance Spectroscopy (LEIS), it was confirmed that this combinatorial high-throughput system could be used to identify the composition with the optimal grain orientation growth, microstructure and electrical properties systematically, through accurately monitoring the doping content and material composition. According to the characterization results, a Sb2Se3 quasi-liquid phase promoted CIGS film-growth model has been put forward. In addition to CIGS thin film reported here, the combinatorial CBD also could be applied to the high-throughput screening of other sulfide thin film material systems.

  1. Preparation of Hydrophobic Metal-Organic Frameworks via Plasma Enhanced Chemical Vapor Deposition of Perfluoroalkanes for the Removal of Ammonia

    Science.gov (United States)

    DeCoste, Jared B.; Peterson, Gregory W.

    2013-01-01

    Plasma enhanced chemical vapor deposition (PECVD) of perfluoroalkanes has long been studied for tuning the wetting properties of surfaces. For high surface area microporous materials, such as metal-organic frameworks (MOFs), unique challenges present themselves for PECVD treatments. Herein the protocol for development of a MOF that was previously unstable to humid conditions is presented. The protocol describes the synthesis of Cu-BTC (also known as HKUST-1), the treatment of Cu-BTC with PECVD of perfluoroalkanes, the aging of materials under humid conditions, and the subsequent ammonia microbreakthrough experiments on milligram quantities of microporous materials. Cu-BTC has an extremely high surface area (~1,800 m2/g) when compared to most materials or surfaces that have been previously treated by PECVD methods. Parameters such as chamber pressure and treatment time are extremely important to ensure the perfluoroalkane plasma penetrates to and reacts with the inner MOF surfaces. Furthermore, the protocol for ammonia microbreakthrough experiments set forth here can be utilized for a variety of test gases and microporous materials. PMID:24145623

  2. Characterization of Si:O:C:H films fabricated using electron emission enhanced chemical vapour deposition

    Energy Technology Data Exchange (ETDEWEB)

    Durrant, Steven F. [Laboratorio de Plasmas Tecnologicos, Campus Experimental de Sorocaba, Universidade Estadual Paulista-UNESP, Avenida Tres de Marco, 511, Alto da Boa Vista, 18087-180, Soracaba, SP (Brazil)], E-mail: steve@sorocaba.unesp.br; Rouxinol, Francisco P.M.; Gelamo, Rogerio V. [Instituto de Fisica Gleb Wataghin, Universidade Estadual de Campinas, 13083-970, Campinas, SP (Brazil); Trasferetti, B. Claudio [Present address: Superintendencia Regional da Policia Federal em Sao Paulo, Setor Tecnico-Cientifico, Rua Hugo d' Antola 95/10o Andar, Lapa de Baixo, 05038-090 Sao Paulo, SP (Brazil); Davanzo, C.U. [Instituto de Quimica, Universidade Estadual de Campinas, 13083-970, Campinas, SP (Brazil); Bica de Moraes, Mario A. [Instituto de Fisica Gleb Wataghin, Universidade Estadual de Campinas, 13083-970, Campinas, SP (Brazil)

    2008-01-15

    Silicon-based polymers and oxides may be formed when vapours of oxygen-containing organosilicone compounds are exposed to energetic electrons drawn from a hot filament by a bias potential applied to a second electrode in a controlled atmosphere in a vacuum chamber. As little deposition occurs in the absence of the bias potential, electron impact fragmentation is the key mechanism in film fabrication using electron-emission enhanced chemical vapour deposition (EEECVD). The feasibility of depositing amorphous hydrogenated carbon films also containing silicon from plasmas of tetramethylsilane or hexamethyldisiloxane has already been shown. In this work, we report the deposition of diverse films from plasmas of tetraethoxysilane (TEOS)-argon mixtures and the characterization of the materials obtained. The effects of changes in the substrate holder bias (V{sub S}) and of the proportion of TEOS in the mixture (X{sub T}) on the chemical structure of the films are examined by infrared-reflection absorption spectroscopy (IRRAS) at near-normal and oblique incidence using unpolarised and p-polarised, light, respectively. The latter is particularly useful in detecting vibrational modes not observed when using conventional near-normal incidence. Elemental analyses of the film were carried out by X-ray photoelectron spectroscopy (XPS), which was also useful in complementary structural investigations. In addition, the dependencies of the deposition rate on V{sub S} and X{sub T} are presented.

  3. Synthesis of electro-active manganese oxide thin films by plasma enhanced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Merritt, Anna R. [Energetics Research Division, Naval Air Warfare Center Weapons Division, China Lake, CA 93555 (United States); Rajagopalan, Ramakrishnan [Department of Engineering, The Pennsylvania State University, Dubois, PA 15801 (United States); Materials Research Institute, The Pennsylvania State University, University Park, PA 16802 (United States); Carter, Joshua D. [Energetics Research Division, Naval Air Warfare Center Weapons Division, China Lake, CA 93555 (United States)

    2014-04-01

    The good stability, cyclability and high specific capacitance of manganese oxide (MnO{sub x}) has recently promoted a growing interest in utilizing MnO{sub x} in asymmetric supercapacitor electrodes. Several literature reports have indicated that thin film geometries of MnO{sub x} provide specific capacitances that are much higher than bulk MnO{sub x} powders. Plasma enhanced chemical vapor deposition (PECVD) is a versatile technique for the production of metal oxide thin films with high purity and controllable thickness. In this work, MnO{sub x} thin films deposited by PECVD from a methylcyclopentadienyl manganese tricarbonyl precursor are presented and the effect of processing conditions on the quality of MnO{sub x} films is described. The film purity and oxidation state of the MnO{sub x} films were studied by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Preliminary electrochemical testing of MnO{sub x} films deposited on carbon fiber electrodes in aqueous electrolytes indicates that the PECVD synthesized films are electrochemically active. - Highlights: • Plasma enhanced chemical vapor deposition of manganese oxide thin films. • Higher plasma power and chamber pressure increase deposition rate. • Manganese oxide thin films are electrochemically active. • Best electrochemical performance observed for pure film with low stress • Lower capacitance observed at higher scan rates despite thin film geometry.

  4. Characterization of Si:O:C:H films fabricated using electron emission enhanced chemical vapour deposition

    International Nuclear Information System (INIS)

    Durrant, Steven F.; Rouxinol, Francisco P.M.; Gelamo, Rogerio V.; Trasferetti, B. Claudio; Davanzo, C.U.; Bica de Moraes, Mario A.

    2008-01-01

    Silicon-based polymers and oxides may be formed when vapours of oxygen-containing organosilicone compounds are exposed to energetic electrons drawn from a hot filament by a bias potential applied to a second electrode in a controlled atmosphere in a vacuum chamber. As little deposition occurs in the absence of the bias potential, electron impact fragmentation is the key mechanism in film fabrication using electron-emission enhanced chemical vapour deposition (EEECVD). The feasibility of depositing amorphous hydrogenated carbon films also containing silicon from plasmas of tetramethylsilane or hexamethyldisiloxane has already been shown. In this work, we report the deposition of diverse films from plasmas of tetraethoxysilane (TEOS)-argon mixtures and the characterization of the materials obtained. The effects of changes in the substrate holder bias (V S ) and of the proportion of TEOS in the mixture (X T ) on the chemical structure of the films are examined by infrared-reflection absorption spectroscopy (IRRAS) at near-normal and oblique incidence using unpolarised and p-polarised, light, respectively. The latter is particularly useful in detecting vibrational modes not observed when using conventional near-normal incidence. Elemental analyses of the film were carried out by X-ray photoelectron spectroscopy (XPS), which was also useful in complementary structural investigations. In addition, the dependencies of the deposition rate on V S and X T are presented

  5. Young Investigator Proposal, Research Area 7.4 Reactive Chemical Systems: Multifunctional, Bimetallic Nanomaterials Prepared by Atomic Layer Electroless Deposition

    Science.gov (United States)

    2017-09-30

    Report: Young Investigator Proposal, Research Area 7.4 Reactive Chemical Systems: Multifunctional, Bimetallic Nanomaterials Prepared by Atomic Layer ...Chemical Systems: Multifunctional, Bimetallic Nanomaterials Prepared by Atomic Layer Electroless Deposition Report Term: 0-Other Email: pcappillino... Layer Electroless Deposition (ALED, Figure 1) is the ability to tune growth mechanism, hence growth morphology, by altering conditions. In this

  6. Characterization of thin film deposits on tungsten filaments in catalytic chemical vapor deposition using 1,1-dimethylsilacyclobutane

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Yujun, E-mail: shiy@ucalgary.ca; Tong, Ling; Mulmi, Suresh [Department of Chemistry, University of Calgary, Calgary, Alberta T2N 1N4 (Canada)

    2016-09-15

    Metal filament plays a key role in the technique of catalytic chemical vapor deposition (Cat-CVD) as it serves as a catalyst in dissociating the source gas to form reactive species. These reactive species initiate the gas-phase reaction chemistry and final thin film and nanostructure formation. At the same time, they also react with the metal itself, leading to the formation of metal alloys and other deposits. The deposits on the tungsten filaments when exposed to 1,1-dimethylsilacyclobutane (DMSCB), a single-source precursor for silicon carbide thin films, in the process of Cat-CVD were studied in this work. It has been demonstrated that a rich variety of deposits, including tungsten carbides (W{sub 2}C and WC), tungsten silicide (W{sub 5}Si{sub 3}), silicon carbide, amorphous carbon, and graphite, form on the W filament surfaces. The structural and morphological changes in the tungsten filaments depend strongly on the DMSCB pressure and filament temperature. At 1000 and 2000 °C, the formation of WC and W{sub 2}C dominates. In addition, a thin amorphous carbon layer has been found at 1500 °C with the 0.12 and 0.24 Torr of DMSCB and a lower temperature of 1200 °C with the 0.48 Torr of DMSCB. An increase in the DMSCB sample pressure gives rise to higher Si and C contents. As a result, the formation of SiC and W{sub 5}Si{sub 3} has been observed with the two high-pressure DMSCB samples (i.e., 0.24 and 0.48 Torr). The rich decomposition chemistry of DMSCB on the W surfaces is responsible for the extensive changes in the structure of the W filament, providing support for the close relationship between the gas-phase decomposition chemistry and the nature of alloy formation on the metal surface. The understanding of the structural changes obtained from this work will help guide the development of efficient methods to solve the filament aging problem in Cat-CVD and also to achieve a controllable deposition process.

  7. Morphology and growth behavior of O_2-free chemical bath deposited ZnS thin films

    International Nuclear Information System (INIS)

    Jet Meitzner, K.; Tillotson, Brock M.; Siedschlag, Amanda T.; Moore, Frederick G.; Kevan, Stephen D.; Richmond, Geraldine L.

    2015-01-01

    We investigate the role of reagent concentrations and ambient O_2 on the morphology and growth behavior of ZnS thin films grown with the chemical bath deposition method. We investigate the role of substrate on film morphology, and find significant differences between films deposited on SiO_2 versus Si. The films are also sensitive to dissolved O_2 in the bath, as it causes a layer of SiO_2 to form at the ZnS/Si interface during deposition. Degassing of solutions and an N_2 atmosphere are effective to minimize this oxidation, allowing deposition of ZnS films directly onto Si. Under these conditions, we examine film properties as they relate to reagent bath concentrations. As the reagent concentrations are decreased, both the film roughness and growth rate decrease linearly. We also observe deformation and shifting of X-ray diffraction peaks that increases with decreasing reagent concentrations. The shifts are characteristic of lattice compression (caused by the substitution of oxygen for sulfur), and the deformation is characteristic of distortion of the lattice near crystal grain interfaces (caused by tensile stress from interatomic forces between neighboring crystal grains). At the weakest concentrations, the low roughness suggests a mixed growth mode in which both clusters and individual ZnS nanocrystallites contribute to film growth. With increasing reagent concentrations, the growth mode shifts and becomes dominated by deposition of clusters. - Highlights: • We deposit ZnS thin films by chemical bath deposition in an O_2-free environment. • The O_2-free environment is effective to minimize oxidation of the Si substrate. • The dominant growth mechanism changes with reagent concentrations. • Film morphology and composition change with reagent concentrations. • X-ray diffraction reveals tensile stress between ZnS crystal grains.

  8. Precise control of multiwall carbon nanotube diameters using thermal chemical vapor deposition

    Science.gov (United States)

    Siegal, M. P.; Overmyer, D. L.; Provencio, P. P.

    2002-03-01

    We grow multiwall carbon nanotube (CNT) films using thermal chemical vapor deposition at atmospheric pressure using a mixture of acetylene and nitrogen from a 4-nm-thick Ni film catalyst. CNTs are characterized using electron microscopy and Rutherford backscattering spectrometry. CNTs grown with this method are extremely uniform in diameter, both throughout the sample and within the lengths of individual tubes. Nanotube outer diameters, ranging from 5-350 nm, and the total deposition of carbon material, increase exponentially with growth temperature from 630 °C-790 °C.

  9. TPR system: a powerful technique to monitor carbon nanotube formation during chemical vapour deposition

    International Nuclear Information System (INIS)

    Tristao, Juliana Cristina; Moura, Flavia Cristina Camilo; Lago, Rochel Montero; Sapag, Karim

    2010-01-01

    In this work, a TPR (Temperature Programmed Reduction) system is used as a powerful tool to monitor carbon nanotubes production during CVD (Chemical Vapour Deposition), The experiments were carried out using catalyst precursors based on Fe-Mo supported on Al 2 O 3 and methane as carbon source. As methane reacts on the Fe metal surface, carbon is deposited and H2 is produced. TPR is very sensitive to the presence of H2 and affords information on the temperature where catalyst is active to form different forms of carbon, the reaction kinetics, the catalyst deactivation and carbon yields. (author)

  10. Physical and chemical properties of deposited airborne particulates over the Arabian Red Sea coastal plain

    Science.gov (United States)

    Engelbrecht, Johann P.; Stenchikov, Georgiy; Jish Prakash, P.; Lersch, Traci; Anisimov, Anatolii; Shevchenko, Illia

    2017-09-01

    Mineral dust is the most abundant aerosol, having a profound impact on the global energy budget. This research continues our previous studies performed on surface soils in the Arabian Peninsula, focusing on the mineralogical, physical and chemical composition of dust deposits from the atmosphere at the Arabian Red Sea coast. For this purpose, aerosols deposited from the atmosphere are collected during 2015 at six sites on the campus of the King Abdullah University of Science and Technology (KAUST) situated on the Red Sea coastal plain of Saudi Arabia and subjected to the same chemical and mineralogical analysis we conducted on soil samples. Frisbee deposition samplers with foam inserts were used to collect dust and other deposits, for the period December 2014 to December 2015. The average deposition rate measured at KAUST for this period was 14 g m-2 per month, with lowest values in winter and increased deposition rates in August to October. The particle size distributions provide assessments of particle size fractions in the dust deposits.X-ray diffraction (XRD) analysis of a subset of samples confirms variable amounts of quartz, feldspars, micas, and halite, with lesser amounts of gypsum, calcite, dolomite, hematite, and amphibole. Freeze-dried samples were re-suspended onto the Teflon® filters for elemental analysis by X-ray fluorescence (XRF), while splits from each sample were analyzed for water-soluble cations and anions by ion chromatography. The dust deposits along the Red Sea coast are considered to be a mixture of dust emissions from local soils and soils imported from distal dust sources. Airborne mineral concentrations are greatest at or close to dust sources, compared to those through medium- and long-range transport. It is not possible to identify the exact origin of deposition samples from the mineralogical and chemical results alone. These aerosol data are the first of their kind from the Red Sea region. They will help assess their potential

  11. Chemical bath deposited PbS thin films on ZnO nanowires for photovoltaic applications

    Energy Technology Data Exchange (ETDEWEB)

    Gertman, Ronen [Dept of Chemistry, Ben Gurion University of the Negev, Be' er Sheva 84105 (Israel); Ilse Katz Institute for Nanoscale Science and Technology, Ben Gurion University of the Negev, Be' er Sheva 84105 (Israel); Osherov, Anna; Golan, Yuval [Dept of Materials Engineering, Ben Gurion University of the Negev, Be' er Sheva 84105 (Israel); Ilse Katz Institute for Nanoscale Science and Technology, Ben Gurion University of the Negev, Be' er Sheva 84105 (Israel); Visoly-Fisher, Iris, E-mail: irisvf@bgu.ac.il [Ilse Katz Institute for Nanoscale Science and Technology, Ben Gurion University of the Negev, Be' er Sheva 84105 (Israel); Department of Solar Energy and Environmental Physics, Swiss Institute for Dryland Environmental and Energy Research, Jacob Blaustein Institutes for Desert Research, Ben Gurion University of the Negev, Sede Boqer Campus 84990 (Israel)

    2014-01-01

    Photovoltaic devices usually exploit mid-range band-gap semiconductors which absorb in the visible range of the solar spectrum. However, much energy is lost in the IR and near-IR range. We combined the advantages of small band-gap, bulk-like PbS deposited by facile, cheap and direct chemical bath deposition (CBD), with the good electronic properties of ZnO and the large surface area of nanowires, towards low cost photovoltaic devices utilizing IR and near-IR light. Surprisingly, CBD of PbS on ZnO, and particularly on ZnO nanowires, was not studied hitherto. Therefore, the mechanism of PbS growth by chemical bath deposition on ZnO nanowires was studied in details. A visible proof is shown for a growth mechanism starting from amorphous Pb(OH){sub 2} layer, that evolved into the ‘ion-by-ion’ growth mechanism. The growth mechanism and the resulting morphology at low temperatures were controlled by the thiourea concentration. The grain size affected the magnitude of the band-gap and was controlled by the deposition temperatures. Deposition above 40 °C resulted in bulk-like PbS with an optical band-gap of 0.4 eV. Methods were demonstrated for achieving complete PbS coverage of the complex ZnO NW architecture, a crucial requirement in optoelectronic devices to prevent shorts. Measurements of photocurrents under white and near-IR (784 nm) illumination showed that despite a 200 meV barrier for electron transfer at the PbS/ZnO interface, extraction of photo-electrons from PbS to the ZnO was feasible. The ability to harvest electrons from a narrow band-gap semiconductor deposited on a large surface-area electrode can advance the field towards high efficiency, low cost IR and near-IR sensors and third generation solar cells. - Highlights: • PbS was deposited on ZnO nanowires using chemical bath deposition. • At 50 °C the growth mechanism starts from an amorphous Pb(OH){sub 2} layer. • At 5 °C the growth mechanism of PbS can be controlled by thiourea concentrations

  12. Antimony sulfide thin films prepared by laser assisted chemical bath deposition

    International Nuclear Information System (INIS)

    Shaji, S.; Garcia, L.V.; Loredo, S.L.; Krishnan, B.

    2017-01-01

    Highlights: • Antimony sulfide thin films were prepared by normal CBD and laser assisted CBD. • Characterized these films using XRD, XPS, AFM, optical and electrical measurements. • Accelerated growth was observed in the laser assisted CBD process. • These films were photoconductive. - Abstract: Antimony sulfide (Sb_2S_3) thin films were prepared by laser assisted chemical bath deposition (LACBD) technique. These thin films were deposited on glass substrates from a chemical bath containing antimony chloride, acetone and sodium thiosulfate under various conditions of normal chemical bath deposition (CBD) as well as in-situ irradiation of the chemical bath using a continuous laser of 532 nm wavelength. Structure, composition, morphology, optical and electrical properties of the Sb_2S_3 thin films produced by normal CBD and LACBD were analyzed by X-Ray diffraction (XRD), Raman Spectroscopy, Atomic force microscopy (AFM), X-Ray photoelectron spectroscopy (XPS), UV–vis spectroscopy and Photoconductivity. The results showed that LACBD is an effective synthesis technique to obtain Sb_2S_3 thin films for optoelectronic applications.

  13. Dissolution of synthetic uranium dibutyl phosphate deposits in oxidizing and reducing chemical formulations

    International Nuclear Information System (INIS)

    Rufus, A.L.; Sathyaseelan, V.S.; Narasimhan, S.V.; Velmurugan, S.

    2013-01-01

    Graphical abstract: SEM of the U-DBP coated stainless steel coupon before and after exposure to chemical formulation containing acid permanganate at 80 °C. -- Highlights: •Combination of oxidation and reduction processes efficiently dissolves U-DBP deposits. •NP and NAC formulations are compatible with SS-304. •Dissolved uranium and added chemicals are effectively removed via ion exchangers. -- Abstract: Permanganate and nitrilotriacetic acid (NTA) based dilute chemical formulations were evaluated for the dissolution of uranium dibutyl phosphate (U-DBP), a compound that deposits over the surfaces of nuclear reprocessing plants and waste storage tanks. A combination of an acidic, oxidizing treatment (nitric acid with permanganate) followed by reducing treatment (NTA based formulation) efficiently dissolved the U-DBP deposits. The dissolution isotherm of U-DBP in its as precipitated form followed a logarithmic fit. The same chemical treatment was also effective in dissolving U-DBP coated on the surface of 304-stainless steel, while resulting in minimal corrosion of the stainless steel substrate material. Investigation of uranium recovery from the resulting decontamination solutions by ion exchange with a bed of mixed anion and cation resins showed quantitative removal of uranium

  14. Antimony sulfide thin films prepared by laser assisted chemical bath deposition

    Energy Technology Data Exchange (ETDEWEB)

    Shaji, S., E-mail: sshajis@yahoo.com [Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Av. Pedro de Alba s/n, Ciudad Universitaria, San Nicolás de los Garza, Nuevo León, 66455 (Mexico); CIIDIT—Universidad Autónoma de Nuevo León, Apodaca, Nuevo León (Mexico); Garcia, L.V. [Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Av. Pedro de Alba s/n, Ciudad Universitaria, San Nicolás de los Garza, Nuevo León, 66455 (Mexico); Loredo, S.L. [Centro de Investigación en Materiales Avanzados (CIMAV), Unidad Monterrey, PIIT, Apodaca, Nuevo León (Mexico); Krishnan, B. [Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Av. Pedro de Alba s/n, Ciudad Universitaria, San Nicolás de los Garza, Nuevo León, 66455 (Mexico); CIIDIT—Universidad Autónoma de Nuevo León, Apodaca, Nuevo León (Mexico); and others

    2017-01-30

    Highlights: • Antimony sulfide thin films were prepared by normal CBD and laser assisted CBD. • Characterized these films using XRD, XPS, AFM, optical and electrical measurements. • Accelerated growth was observed in the laser assisted CBD process. • These films were photoconductive. - Abstract: Antimony sulfide (Sb{sub 2}S{sub 3}) thin films were prepared by laser assisted chemical bath deposition (LACBD) technique. These thin films were deposited on glass substrates from a chemical bath containing antimony chloride, acetone and sodium thiosulfate under various conditions of normal chemical bath deposition (CBD) as well as in-situ irradiation of the chemical bath using a continuous laser of 532 nm wavelength. Structure, composition, morphology, optical and electrical properties of the Sb{sub 2}S{sub 3} thin films produced by normal CBD and LACBD were analyzed by X-Ray diffraction (XRD), Raman Spectroscopy, Atomic force microscopy (AFM), X-Ray photoelectron spectroscopy (XPS), UV–vis spectroscopy and Photoconductivity. The results showed that LACBD is an effective synthesis technique to obtain Sb{sub 2}S{sub 3} thin films for optoelectronic applications.

  15. Dissolution of synthetic uranium dibutyl phosphate deposits in oxidizing and reducing chemical formulations

    Energy Technology Data Exchange (ETDEWEB)

    Rufus, A.L.; Sathyaseelan, V.S.; Narasimhan, S.V.; Velmurugan, S., E-mail: svelu@igcar.gov.in

    2013-06-15

    Graphical abstract: SEM of the U-DBP coated stainless steel coupon before and after exposure to chemical formulation containing acid permanganate at 80 °C. -- Highlights: •Combination of oxidation and reduction processes efficiently dissolves U-DBP deposits. •NP and NAC formulations are compatible with SS-304. •Dissolved uranium and added chemicals are effectively removed via ion exchangers. -- Abstract: Permanganate and nitrilotriacetic acid (NTA) based dilute chemical formulations were evaluated for the dissolution of uranium dibutyl phosphate (U-DBP), a compound that deposits over the surfaces of nuclear reprocessing plants and waste storage tanks. A combination of an acidic, oxidizing treatment (nitric acid with permanganate) followed by reducing treatment (NTA based formulation) efficiently dissolved the U-DBP deposits. The dissolution isotherm of U-DBP in its as precipitated form followed a logarithmic fit. The same chemical treatment was also effective in dissolving U-DBP coated on the surface of 304-stainless steel, while resulting in minimal corrosion of the stainless steel substrate material. Investigation of uranium recovery from the resulting decontamination solutions by ion exchange with a bed of mixed anion and cation resins showed quantitative removal of uranium.

  16. Substrate Effect on Plasma Clean Efficiency in Plasma Enhanced Chemical Vapor Deposition System

    Directory of Open Access Journals (Sweden)

    Shiu-Ko JangJian

    2007-01-01

    Full Text Available The plasma clean in a plasma-enhanced chemical vapor deposition (PECVD system plays an important role to ensure the same chamber condition after numerous film depositions. The periodic and applicable plasma clean in deposition chamber also increases wafer yield due to less defect produced during the deposition process. In this study, the plasma clean rate (PCR of silicon oxide is investigated after the silicon nitride deposited on Cu and silicon oxide substrates by remote plasma system (RPS, respectively. The experimental results show that the PCR drastically decreases with Cu substrate compared to that with silicon oxide substrate after numerous silicon nitride depositions. To understand the substrate effect on PCR, the surface element analysis and bonding configuration are executed by X-ray photoelectron spectroscopy (XPS. The high resolution inductively coupled plasma mass spectrometer (HR-ICP-MS is used to analyze microelement of metal ions on the surface of shower head in the PECVD chamber. According to Cu substrate, the results show that micro Cu ion and the CuOx bonding can be detected on the surface of shower head. The Cu ion contamination might grab the fluorine radicals produced by NF3 ddissociation in the RPS and that induces the drastic decrease on PCR.

  17. Optical and structural characterization of nickel oxide-based thin films obtained by chemical bath deposition

    International Nuclear Information System (INIS)

    Vidales-Hurtado, M.A.; Mendoza-Galvan, A.

    2008-01-01

    Nickel oxide-based thin films were obtained using the chemical bath deposition method on glass and silicon substrates. The precursor solution used was a mixture of nickel nitrate, urea, and deionized water. Molar concentration of nickel (0.3-1.0 M), deposition time, and immersing cycles were considered as deposition variables. Infrared spectroscopy and X-ray diffraction data reveal that all as-deposited films correspond to the transparent turbostratic phase α(II)-Ni(OH) 2 . However, the rate of deposition depends on nickel content in the solution. After annealing in air at temperatures above of 300 deg. C, the films are transformed to the NiO phase and show a grey/black color. In these films, scanning electron microscopy images show aggregates of thin stacked sheets on their surface, such aggregates can be easily removed leaving only a thin NiO layer of about 30 nm adhered firmly to the substrate, regardless of nickel concentration in the solution and deposition time. In order to obtain thicker NiO films with good optical properties a procedure is developed performing several immersing-annealing cycles

  18. Chemical vapour deposition - a promising method for production of different kinds of carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Leonhardt, A.; Ritschel, M.; Bartsch, K.; Graff, A.; Taeschner, C.; Fink, J. [Institut fuer Festkoerper- und Werkstofforschung Dresden e.V. (Germany)

    2001-08-01