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Sample records for av zn cu

  1. On Cu diffusion in ZnO

    Energy Technology Data Exchange (ETDEWEB)

    Herklotz, F.; Lavrov, E.V.; Weber, J. [Technische Universitaet Dresden (Germany)

    2009-07-01

    Copper in ZnO is of special interest since recent theoretical and experimental studies found ferromagnetic behavior of ZnO:Cu at room temperature. In addition, Cu is a deep acceptor in ZnO and one of the causes of the green emission band. Experimental studies of Cu diffusion in bulk ZnO single crystals were carried out in the temperature range 1030 to 1180 C. Concentration profiles of substitutional Cu were determined via IR absorption at 5817 cm{sup -1}. Our findings reveal that the diffusion coefficient of Cu is 7.6 x 10{sup 7} exp(-4.56 eV/k{sub B}T) cm{sup 2}s{sup -1}. This is about a factor of 25 higher than reported in the earlier studies, which probed the total Cu concentration. The discrepancy is explained by the formation of Cu complexes, which occurs at high concentrations. Diffusion mechanisms are discussed.

  2. Cu2ZnSiS4

    Directory of Open Access Journals (Sweden)

    Kimberly A. Rosmus

    2011-04-01

    Full Text Available Single crystals of Cu2ZnSiS4, dicopper(I zinc silicon tetrasulfide, have been prepared via high-temperature solid-state synthesis. Cu2ZnSiS4 was found to have the wurtz-stannite structure type, like that of Li2CdGeS4, Li2CdSnS4, and Cu2CdSiS4. Each sulfur anion is tetrahedrally coordinated by two Cu cations, one Si cation, and one Zn cation, forming a three-dimensional honeycomb structure. When viewed along the c axis, the atoms are aligned in rows in which each cation alternates with the sulfur anions.

  3. [Investigation of spectroscopy of ZnCuInS/ZnSe/ZnS quantum dots].

    Science.gov (United States)

    Lin, Yi-Jun; Liu, Wen-Yan; Zhang, Yu; Bi, Ke; Zhang, Tie-Qiang; Feng, Yi; Wang, Yi-Ding

    2014-01-01

    ZnCuInS/ZnSe/ZnS quantum dots were non-toxic and heavy-metal free semiconductor nanocrystals. In the present paper, ZnCuInS/ZnSe/ZnS core/shell/shell quantum dots were prepared with the particle size of 3.3, 2.7 and 2.3 nm. The photoluminescence of ZnCuInS/ZnSe/ZnS quantum dots with different size were measured, and the wavelength of peak was blue-shifted with decreasing the diameter. The wavelength of absorption peaks and photoluminescence peaks were 510 nm, 611 nm (3.3 nm), 483 nm, 583 nm (2.7 nm) and 447 nm and 545 nm(2.3 nm). The obvious size-dependence of ZnCuInS/ZnSe/ZnS quantum dots was shown. The Stokes shifts of ZnCuInS/ZnSe/ZnS quantum dots were 398 meV (3.3 nm), 436 meV (2.7 nm) and 498 meV (2.3 nm). Such large Stokes shifts indicate that the emission should be ascribed to the defect-related recombination. The temperature-dependent photoluminescence of ZnCuInS/ZnSe/ZnS quantum dots with the particle size of 3.3 nm were measured. The wavelength of peaks was red-shifted with increasing temperature and the intensity of photoluminescence spectra was decreased with increasing temperature. Therefore, the emission was concluded to be the transition from the conduction band to defect state.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-11-01

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

  5. Interfacial Reactions in the Ni/Sn- xZn/Cu Sandwich Couples

    Science.gov (United States)

    Yen, Yee-Wen; Lin, Chung-Yung; Lai, Mei-Ting; Chen, Wan-Ching

    2016-01-01

    The interfacial reactions in Ni/Sn- xZn/Cu sandwich couples which were reflowed at 270°C for 1 h and then aged at 160°C for 1-1000 h were investigated. When the 1000- μm-thick Sn-Zn alloy reacted with Ni and Cu in this couple, the results indicated that the (Ni, Cu)3Sn4, (Ni, Cu)5Zn21, and Ni5Zn21 phases were formed at Sn-1Zn/Ni, Sn-5Zn/Ni, and Sn-9Zn/Ni interfaces for 1 h reflowing, respectively. After 1000 h aging, each intermetallic compound (IMC) was converted to (Cu, Ni, Zn)6Sn5, (Ni, Cu, Sn)5Zn21/Ni5Zn21, and Ni5Zn21 (two layers) phases in the related couples. On the Cu side, the Cu6Sn5 phase in the Sn-1Zn/Cu interface and the Cu5Zn8 phase in the Sn-5Zn/Cu and Sn-9Zn/Cu interfaces were observed when the couple was reflowed at 270°C for 1 h. After 100 h aging, the (Cu, Ni, Zn)6Sn5, Cu5Zn8/(Cu, Zn)6Sn5, and Cu5Zn8 phases were formed at the Sn-1Zn/Cu, Sn-5Zn/Cu and Sn-9Zn/Cu interfaces. When the Sn-Zn alloy thickness was decreased to 500 μm, the (Cu, Ni, Zn)6Sn5 phase at the Sn-1Zn/Ni interface and the (Ni, Cu, Sn)5Zn21 phase at the Sn-5Zn/Ni and Sn-9Zn/Ni interfaces were observed after 1 h reflowing. When the couple was aged at 160°C for 1000 h, each IMC was converted to (Cu, Ni, Zn)6Sn5 and Cu5Zn8/(Cu, Ni, Sn)Zn/Ni5Zn21 phases at the Sn-1Zn/Ni and Sn-(5, 9)Zn/Ni interfaces. (Cu, Ni, Zn)6Sn5 and Cu5Zn8 were, respectively, formed at the Sn-1Zn/Cu and Sn-(5, 9)Zn/Cu interfaces for 1 h reflowing. After 100 h aging, the IMCs were converted to (Cu, Ni, Zn)6Sn5 and Cu5Zn8/(Cu, Zn)6Sn5 phases. This current study reveals that the IMC formation in Ni/(Sn- xZn)/Cu sandwich couples are very sensitive to the Zn concentration and thickness in Sn- xZn alloys.

  6. On diffusion of Cu in ZnO

    Energy Technology Data Exchange (ETDEWEB)

    Herklotz, F., E-mail: frank.herklotz@physik.tu-dresden.d [Institut fuer Angewandte Physik, Technische Universitaet Dresden, 01062 Dresden (Germany); Lavrov, E.V.; Weber, J. [Institut fuer Angewandte Physik, Technische Universitaet Dresden, 01062 Dresden (Germany)

    2009-12-15

    An experimental study of Cu diffusion in bulk ZnO single crystals in the temperature range 1012-1220 deg. C is presented. Concentration profiles of substitutional Cu were determined by IR absorption at 5817cm{sup -1}. Our findings reveal that Cu in ZnO diffuses faster than previously reported [G. Mueller, R. Helbig, J. Phys. Chem. Solids 32 (1971) 1971]. The discrepancy is tentatively explained by the formation of Cu complexes, which occurs at high Cu concentrations.

  7. Ferromagnetism in CuO-ZnO multilayers

    Science.gov (United States)

    Chandran, Sudakar; Kirby, B. J.; Padmanabhan, K.; Lawes, G.; Naik, R.; Kumar, Sanjiv; Naik, V. M.

    2008-03-01

    The magnetic properties of CuO-ZnO heterostructures are examined to elucidate the origin of the ferromagnetic signature in Cu doped ZnO. The CuO and ZnO layer thickness varied from 15 nm to 350 nm, and we observed no significant diffusion of either Cu^2+ in the ZnO layers or of Zn^2+ in the CuO layers using Rutherford backscattering spectrometry. Bulk magnetization measurements established that the multilayers exhibit a ferromagnetic moment at room temperature, with a saturation magnetization (˜2-5 emu/cc of CuO) that depends on the CuO size, but not the CuO-ZnO interfacial area. Polarized neutron reflection studies suggest that the ferromagnetism arises from the CuO layers, and not from the interdiffusion of CuO and ZnO. These results indicate that the ferromagnetism in these multicomponent structures arises from the uncompensated surface spins of CuO nanoparticles in the layer rather than from regions of interdiffusing ZnO and CuO.

  8. Effect of temperature on mechanical alloying of Cu-Zn and Cu-Cr system

    Institute of Scientific and Technical Information of China (English)

    ZUO Ke-sheng; XI Sheng-qi; ZHOU Jin-gen

    2009-01-01

    Cu-Zn and Cu-Cr powders were milled with an attritor mill at room temperature, -10, -20 and -30 ℃, respectively. Phase transformation and morphology evolution of the alloyed powder were investigated by X-ray diffractometry(XRD), X-ray photoelectron spectroscopy(XPS) and scanning electron microscopy(SEM). The results show that lowering temperature can delay mechanical alloying(MA) process of Cu-Zn system with negative mixing enthalpy, and promote MA process of Cu-Cr system with positive mixing enthalpy. As for Cu-Cr and Cu-Zn powders milled at -10 ℃, lamellar structures are firstly formed, while fewer lamellar particles can be found when the powder is milled at -20 ℃. When the alloyed powder is annealed at 1 000 ℃, Cu(Cr) solid solution is decomposed and Cr precipitates from Cu matrix, whereas Cu(Zn) solid solution keeps stable.

  9. Tuning of properties of sprayed CuZnS films

    Science.gov (United States)

    Sreejith, M. S.; Deepu, D. R.; Kartha, C. Sudha; Vijayakumar, K. P.

    2014-04-01

    CuZnS is an alloy having mixed structure of CuxS and ZnS. Here we studied the structural, optical, compositional and electrical properties of CuZnS films prepared using chemical spray pyrolysis (CSP). Just by varying ratio of Cu to Zn was observed that material can be changed from P type to N type and electrical conductivity can be increased by 4 orders. Increase in concentration of Cu leads to decrease bandgap to 1.8 eV from 3.4 eV. CuZnS films having high concentration of copper can be used as good absorber and weakly doped films as buffer / window layers in solar cells.

  10. Room temperature ferromagnetism in Cu-doped ZnO synthesized from CuO and ZnO nanoparticles

    Science.gov (United States)

    Owens, Frank J.

    2009-11-01

    AC susceptibility and ferromagnetic resonance (FMR) measurements indicate that ZnO doped with Cu by a simple sintering process starting from nanoparticles of ZnO and CuO is ferromagnetic above room temperature. FMR measurements above room temperature indicate the ordering temperature to be above 520 K. The observation supports the recent theoretical calculations of Huang et al. which predict ferromagnetism in copper-doped ZnO.

  11. Effect of dietary Zn on high Cu intake in sheep

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, P.J.

    1976-01-01

    The objective was to determine whether high dietary levels of Zn will ameliorate or prevent chronic Cu toxicity in lambs fed a high Cu containing finishing diet. Four-month-old crossbred lambs were individually fed a pelleted diet of 35% cottonseed hulls, 5% alfalfa, 1.6% urea, 57.4% corn meal, vitamins A and D and minerals. The ration supplements and number of head per treatment were: group 1, none (4); group 2, 45 ppm Cu (5);group 3, 45 ppm Cu plus 250 ppm Zn (5), group 4, 45 ppm Cu plus 500 ppm Zn. The Cu and Zn supplements were CuSO/sub 4/ and ZnO. Plasma aspartate transaminase (AspT) activity, measured biweekly, was first elevated after 41 days feeding. Thereafter, in group 2, one lamb died and the AspT levels of the others gradually increased to a point where death from chronic Cu toxicity seemed imminent; the lambs in all groups were then slaughtered after 91 days feeding. Mean plasma AspT (SF units/ml) and liver Cu and Zn (..mu..g/g DM) at slaughter were, respectively: group 1, 65, 232 and 118; group 2, 308, 1074 and 135; group 3, 130, 705 and 139; group 4, 194, 1145 and 179. Neither Zn level reduced (P > .05) liver Cu; both reduced (P < .05) AspT activity late in the study, but not to control levels (P < .05). Thus, chronic Cu toxicity may be delayed, but not prevented, by high Zn levels.

  12. Process of electroless plating Cu-Sn-Zn ternary alloy

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Cu-Sn-Zn ternary alloy layer with 10 μm thickness was prepared through electroless plating method. The influences of process conditions including the concentration of metallic salts, reductant and complex agent on Cu-Sn-Zn alloy were studied in details.The stability to bear color changes and corrosion resistance of Cu-Sn-Zn film layer were studied through air-exposure experiment and electrochemical analyses test respectively. The results show that the performances of Cu-Sn-Zn film layer are obviously superior to brass matrix. By use of SEM,EDS and XRD, the morphology, microstructure and chemical composition were investigated. The results show that complex agent can increase the content of Sn and Zn, improve the evenness and compactness and decrease needle holes, therefore the properties of electroless plating layer such as the stability to bear color changes and corrosion resistance are improved remarkably.The probable mechanism of complex agent was discussed.

  13. Cu,Zn-superoxide dismutase without Zn is folded but catalytically inactive.

    Science.gov (United States)

    Nedd, Sean; Redler, Rachel L; Proctor, Elizabeth A; Dokholyan, Nikolay V; Alexandrova, Anastassia N

    2014-12-12

    Amyotrophic lateral sclerosis has been linked to the gain of aberrant function of superoxide dismutase, Cu,Zn-SOD1 upon protein misfolding. The mechanism of SOD1 misfolding is thought to involve mutations leading to the loss of Zn, followed by protein unfolding and aggregation. We show that the removal of Zn from SOD1 may not lead to an immediate unfolding but immediately deactivates the enzyme through a combination of subtle structural and electronic effects. Using quantum mechanics/discrete molecular dynamics, we showed that both Zn-less wild-type (WT)-SOD1 and its D124N mutant that does not bind Zn have at least metastable folded states. In those states, the reduction potential of Cu increases, leading to the presence of detectable amounts of Cu(I) instead of Cu(II) in the active site, as confirmed experimentally. The Cu(I) protein cannot participate in the catalytic Cu(I)-Cu(II) cycle. However, even without the full reduction to Cu(I), the Cu site in the Zn-less variants of SOD1 is shown to be catalytically incompetent: unable to bind superoxide in a way comparable to the WT-SOD1. The changes are more radical and different in the D124N Zn-less mutant than in the Zn-less WT-SOD1, suggesting D124N being perhaps not the most adequate model for Zn-less SOD1. Overall, Zn in SOD1 appears to be influencing the Cu site directly by adjusting its reduction potential and geometry. Thus, the role of Zn in SOD1 is not just structural, as was previously thought; it is a vital part of the catalytic machinery.

  14. Characterization of ZnO/Cu/ZnO multilayers structure for solar cell devices

    Science.gov (United States)

    Rasheed, Hiba S.; Hassan, Z.; Ahmed, Naser M.; Sabah, Fayroz A.; Azzez, Shrook A.; Al-Hazim, Nabeel Z.

    2016-07-01

    A series of ZnO/Cu/ZnO multilayer films has been fabricated from zinc and copper metallic targets by simultaneous RF and DC magnetron sputtering. The influences of the ZnO and Cu layer thicknesses, and Ar flow rate on the optical, electrical and structural properties of the films were investigated. The optical and electrical properties of the multilayers were studied by optical spectrometry and four point probe measurements, respectively. The thickness of the ZnO layers were varied between 20 and 60 nm and the Cu layers were between 5 and 15 nm, the optimum thin film structures were deposited under 12 sccm Ar flow rate. Low sheet resistance and high transmittance were obtained when the film was prepared using thickness of ZnO (60 nm)/Cu (15 nm)/ZnO (60 nm).

  15. Aqueous synthesis of internally doped Cu:ZnSe/ZnS core-shell nanocrystals with good stability.

    Science.gov (United States)

    Xu, Shuhong; Wang, Chunlei; Wang, Zhuyuan; Zhang, Haisheng; Yang, Jing; Xu, Qinying; Shao, Haibao; Li, Rongqing; Lei, Wei; Cui, Yiping

    2011-07-08

    To prepare biologically available Zn-based NCs in aqueous solution, we herein reported the synthesis of aqueous Cu:ZnSe/ZnS NCs with internally doped aqueous Cu:ZnSe NCs as the core template. Due to the dual protection of Cu impurities by the ZnSe core and ZnS shells, the as-prepared Cu:ZnSe/ZnS NCs show excellent stability in the open air, which overcomes the intrinsic instability of traditional aqueous Cu:ZnSe NCs. The as-prepared Cu:ZnSe/ZnS NCs possess extremely good stability, good biocompatibility and lower cytotoxicity, and thus can be used as a promising candidate for fluorescent NC-based biological applications.

  16. pyridine Zn(II) and Cu(II) Complexes

    African Journals Online (AJOL)

    NICO

    2014-09-03

    Sep 3, 2014 ... The kinetics, mechanism and polymer microstructure studies of ring-opening polymerization (ROP) of lactides (LA) by Zn(II) and Cu(II) ... transparency, ease of processing and ease of microbial decompo- sition or degradation.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-11-01

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

  18. Cu-Zn disorder in Cu2ZnGeSe4: A complementary neutron diffraction and Raman spectroscopy study

    Science.gov (United States)

    Gurieva, G.; Többens, D. M.; Valakh, M. Ya.; Schorr, S.

    2016-12-01

    The crystal structure of the quaternary compound semiconductor Cu2ZnGeSe4 (CZGSe) was investigated by the complementary use of neutron diffraction, and Raman spectroscopy. The powder sample, which resulting from wavelength dispersive X-ray spectroscopy (WDX) turned out to be single phase Cu-rich CZGSe, was synthesized by solid state reaction of the pure elements in an evacuated silica tube at 700 °C. Raman spectroscopy confirmed the homogeneity and phase purity of the sample, in addition, the kesterite type structure was suggested. Rietveld analysis of the neutron diffraction data confirmed that the compound crystallizes in the tetragonal kesterite type structure. The refined site occupancy factors were used to determine the average neutron scattering lengths of the cation sites, giving insights into cation distribution and finally point defect types. Thus it has been shown, that additional to the CuZn-ZnCu anti-site defects in the lattice planes at z=¼ and ¾ (Cu-Zn disorder) also the off-stoichiometry type related point defects like Cui and CuZn occur in Cu-rich CZGSe.

  19. Fatigue crack behavior on a Cu-Zn-Al SMA

    OpenAIRE

    V. Di Cocco; Iacoviello, F.; Natali, S.; V. Volpe

    2014-01-01

    In recent years, mechanical property of many SMA has improved in order to introduce these alloys in specific field of industry. Main examples of these alloys are the NiTi, Cu-Zn-Al and Cu-Al-Ni which are used in many fields of engineering such as aerospace or mechanical systems. Cu-Zn-Al alloys are characterized by good shape memory properties due to a bcc disordered structure stable at high temperature called β-phase, which is able to change by means of a reversible transition to...

  20. Research Update: Stable single-phase Zn-rich Cu2ZnSnSe4 through In doping

    Science.gov (United States)

    Hartnauer, Stefan; Körbel, Sabine; Marques, Miguel A. L.; Botti, Silvana; Pistor, Paul; Scheer, Roland

    2016-07-01

    Alloying in the system Cu2ZnSnSe4-CuInSe2-ZnSe (CZTISe) is investigated experimentally and theoretically. The goal is to distinguish single-phase and multi-phase regions within the Cu2ZnSnSe4-2CuInSe2-4ZnSe pseudo-ternary phase diagram. CZTISe thin films are prepared by co-evaporation of the chemical elements and are investigated in real-time during growth using in situ angle dispersive X-ray diffraction. The focus is mainly on thin films along the Cu2ZnSnSe4-2CuInSe2 isopleth with small ZnSe addition as well as on films along the Cu2ZnSnSe4-4ZnSe isopleth with small CuInSe2 addition. For both cases, ab initio calculations with density-functional theory are performed to estimate the stability of the alloy with respect to the formation of secondary phases. Both in experiment and calculation, we find a surprisingly large single-phase region in the Cu2ZnSnSe4 corner of the pseudo-ternary phase diagram slightly off the Cu2ZnSnSe4-4ZnSe isopleth. This may help avoiding secondary phase formation under Zn-rich conditions and open up new possibilities for the application of CZTISe thin films in solar cells.

  1. Exploring the activated state of Cu/ZnO-Zn, a model catalyst for methanol synthesis

    NARCIS (Netherlands)

    Batyrev, E.D.; Shiju, N.R.; Rothenberg, G.

    2012-01-01

    The interaction of Cu clusters with ZnO(0001)-Zn terminated crystal faces is studied after reduction at high temperatures by a combination of scanning tunneling microscopy, scanning tunneling spectroscopy, X-ray photoelectron spectroscopy (XPS), and thermal desorption spectroscopy. We find that tiny

  2. Colloidal synthesis of Cu-ZnO and Cu@CuNi-ZnO hybrid nanocrystals with controlled morphologies and multifunctional properties.

    Science.gov (United States)

    Zeng, Deqian; Gong, Pingyun; Chen, Yuanzhi; Zhang, Qinfu; Xie, Qingshui; Peng, Dong-Liang

    2016-06-02

    Metal-semiconductor hybrid nanocrystals have received extensive attention owing to their multiple functionalities which can find wide technological applications. The utilization of low-cost non-noble metals to construct novel metal-semiconductor hybrid nanocrystals is important and meaningful for their large-scale applications. In this study, a facile solution approach is developed for the synthesis of Cu-ZnO hybrid nanocrystals with well-controlled morphologies, including nanomultipods, core-shell nanoparticles, nanopyramids and core-shell nanowires. In the synthetic strategy, Cu nanocrystals formed in situ serve as seeds for the heterogeneous nucleation and growth of ZnO, and it eventually forms various Cu-ZnO hetero-nanostructures under different reaction conditions. These hybrid nanocrystals possess well-defined and stable heterostructure junctions. The ultraviolet-visible-near infrared spectra reveal morphology-dependent surface plasmon resonance absorption of Cu and the band gap absorption of ZnO. Furthermore, we construct a novel Cu@CuNi-ZnO ternary hetero-nanostructure by incorporating the magnetic metal Ni into the pre-synthesized colloidal Cu nanocrystals. Such hybrid nanocrystals possess a magnetic Cu-Ni intermediate layer between the ZnO shell and the Cu core, and exhibit ferromagnetic/superparamagnetic properties which expand their functionalities. Finally, enhanced photocatalytic activities are observed in the as-prepared non-noble metal-ZnO hybrid nanocrystals. This study not only provides an economical way to prepare high-quality morphology-controlled Cu-ZnO hybrid nanocrystals for potential applications in the fields of photocatalysis and photovoltaic devices, but also opens up new opportunities in designing ternary non-noble metal-semiconductor hybrid nanocrystals with multifunctionalities.

  3. Punicalagin Green Functionalized Cu/Cu2O/ZnO/CuO Nanocomposite for Potential Electrochemical Transducer and Catalyst

    Science.gov (United States)

    Fuku, X.; Kaviyarasu, K.; Matinise, N.; Maaza, M.

    2016-09-01

    A novel ternary Punica granatum L-Cu/Cu2O/CuO/ZnO nanocomposite was successfully synthesised via green route. In this work, we demonstrate that the green synthesis of metal oxides is more viable and facile compare to other methods, i.e., physical and chemical routes while presenting a potential electrode for energy applications. The prepared nanocomposite was characterised by both microscopic and spectroscopic techniques. High-resolution scanning electron microscopy (HRSEM) and X-ray diffraction (XRD) techniques revealed different transitional phases with an average nanocrystallite size of 29-20 mm. It was observed that the nanocomposites changed from amorphous-slightly crystalline Cu/Cu2O to polycrystalline Cu/Cu2O/CuO/ZnO at different calcination temperatures (room temperature-RT- 600 °C). The Cu/Cu2O/ZnO/CuO metal oxides proved to be highly crystalline and showed irregularly distributed particles with different sizes. Meanwhile, Fourier transform infrared (FTIR) spectroscopy confirmed the purity while together with ultraviolet-visible (UV-Vis) spectroscopy proved the proposed mechanism of the synthesised nanocomposite. UV-Vis showed improved catalytic activity of the prepared metal oxides, evident by narrow band gap energy. The redox and electrochemical properties of the prepared nanocomposite were achieved by cyclic voltammetry (CV), electrochemical impedance (EIS) and galvanostatic charge-discharge (GCD). The maximum specific capacitance ( C s) was calculated to be 241 F g-1 at 50 mV s-1 for Cu/Cu2O/CuO/ZnO nanoplatelets structured electrode. Moreover, all the CuO nanostructures reveal better power performance, excellent rate as well as long term cycling stability. Such a study will encourages a new design for a wide spectrum of materials for smart electronic device applications.

  4. Influence of Zn content and annealing process on electrical property of CuZn alloy

    Institute of Scientific and Technical Information of China (English)

    罗丰华; 尹志民; 汪明朴; 左铁镛

    2001-01-01

    The relationship among annealing temperature, microstructure and electrical resistivity of Cu-(8%~13%)Zn (mole fraction) alloys was studied. The results show that the relationship between the electrical resistivity of cold deformation CuZn alloy and annealing temperature is related to the recovery and recrystallization of the processes. The increments of electrical resistivity due to strain are restored mainly on the process of recovery and recrystallization. The room temperature resistivity of soft state alloys is linear to the Zn contents. The extended application of Matthissen rule on high concentration solid solution was discussed.

  5. The properties of CdTe solar cells with ZnTe/ZnTe: Cu buffer layers

    Institute of Scientific and Technical Information of China (English)

    Song Huijin; Zheng Jiagui; Feng Lianghuan; Yan Qiang; Lei Zhi; Wu Lili; Zhang Jingquan; Li Wei; Li Bing

    2008-01-01

    CdS/CdTe solar cells with ZnTe/ZnTe:Cu buffer layers were fabricated and studied. The energy band structure of it was analyzed. The C-V, I-V characteristics and the spectral response show that the ZnTe/ZnTe:Cu buffer layers improve the back contact characteristic properties, the diode characteristics of the forward junction and the short-wave spectral response of the CdTe solar cells. The ZnTe/ZnTe:Cu buffer layers affect the solar cell conversion efficiency and its fill factor.

  6. Medical applications of Cu, Zn, and S isotope effects.

    Science.gov (United States)

    Albarede, Francis; Télouk, Philippe; Balter, Vincent; Bondanese, Victor P; Albalat, Emmanuelle; Oger, Philippe; Bonaventura, Paola; Miossec, Pierre; Fujii, Toshiyuki

    2016-10-01

    This review examines recent applications of stable copper, zinc and sulfur isotopes to medical cases and notably cancer. The distribution of the natural stable isotopes of a particular element among coexisting molecular species varies as a function of the bond strength, the ionic charge, and the coordination, and it also changes with kinetics. Ab initio calculations show that compounds in which a metal binds to oxygen- (sulfate, phosphate, lactate) and nitrogen-bearing moieties (histidine) favor heavy isotopes, whereas bonds with sulfur (cysteine, methionine) favor light isotopes. Oxidized cations (e.g., Cu(ii)) and low coordination numbers are expected to favor heavy isotopes relative to their reduced counterparts (Cu(i)) and high coordination numbers. Here we discuss the first observations of Cu, Zn, and S isotopic variations, three elements closely related along multiple biological pathways, with emphasis on serum samples of healthy volunteers and of cancer patients. It was found that heavy isotopes of Zn and to an even greater extent Cu are enriched in erythrocytes relative to serum, while the difference is small for sulfur. Isotopic variations related to age and sex are relatively small. The (65)Cu/(63)Cu ratio in the serum of patients with colon, breast, and liver cancer is conspicuously low relative to healthy subjects. The characteristic time over which Cu isotopes may change with disease progression (a few weeks) is consistent with both the turnover time of the element and albumin half-life. A parallel effect on sulfur isotopes is detected in a few un-medicated patients. Copper in liver tumor tissue is isotopically heavy. In contrast, Zn in breast cancer tumors is isotopically lighter than in healthy breast tissue. (66)Zn/(64)Zn is very similar in the serum of cancer patients and in controls. Possible reasons for Cu isotope variations may be related to the cytosolic storage of Cu lactate (Warburg effect), release of intracellular copper from cysteine

  7. Phase transformation of Al-Zn (Cu) alloys and the phase diagram of Al-Zn-Cu system%Al-Zn(Cu)合金的相变和Al-Zn-Cu系相图

    Institute of Scientific and Technical Information of China (English)

    郝士明; 李洪晓; 陈辉

    2005-01-01

    The room temperature phase diagram of Al-Zn-Cu system is the important basis for judging the phase constituents of the materials at the usage condition. New results about the room temperature phase diagram of the low copper side in the Al-Zn-Cu systems have been shown in this study. Miscibility gap of fcc phase in the Al-Zn-Cu system has also been studied by experimental diffusion-couple method and thermodynamic calculation. Properties of this miscibility gap have been known. It is practically significant for the study on the aging behavior and for the control of the microstructure and properties of the Al alloys with Zn and Cu element.

  8. Conduction behavior conversion for Cu-doped ZnS/n-type Si devices with different Cu contents

    Science.gov (United States)

    Ni, Wei-Shih; Lin, Yow-Jon

    2015-06-01

    Currents through Cu-doped ZnS (ZnCuS)/n-type Si structures were studied. The electrical conduction investigations suggest that the carrier transport behavior is governed by the Poole-Frenkel emission for ZnCuS/n-type Si devices having the low Cu concentration. However, the carrier transport behavior is governed by the thermionic emission for ZnCuS/n-type Si devices having the high Cu concentration. The photoluminescence result revealed that sulfur vacancy ( V S) is the origin of conduction behavior conversion. It is shown that the increased Cu concentration leads to the reduced formation probability of V S. The dependence of V S on the film composition was identified for providing a guide to control the current transport behavior of ZnCuS/n-type Si devices.

  9. Electrodeposited Cu2ZnSnS4 thin films

    CSIR Research Space (South Africa)

    Valdes, M

    2014-05-01

    Full Text Available Electrochimica Acta Vol. 128, pp 393-399 Electrodeposited Cu2ZnSnS4thin films M. Valdesa, M. Modibedib, M. Matheb, T. Hilliec,d, M. Vazqueza,∗ aDivisión Electroquimica y Corrosión, INTEMA, UNMdP-CONICET, J. B. Justo 4302 B7608FDQ Mar del Plata, Argentina...

  10. Tuning the emission of aqueous Cu:ZnSe quantum dots to yellow light window.

    Science.gov (United States)

    Wang, Chunlei; Hu, Zhiyang; Xu, Shuhong; Wang, Yanbin; Zhao, Zengxia; Wang, Zhuyuan; Cui, Yiping

    2015-07-31

    Synthesis of internally doped Cu:ZnSe QDs in an aqueous solution still suffers from narrow tunable emissions from the blue to green light window. In this work, we extended the emission window of aqueous Cu:ZnSe QDs to the yellow light window. Our results show that high solution pH, multiple injections of Zn precursors, and nucleation doping strategy are three key factors for preparing yellow emitted Cu:ZnSe QDs. All these factors can depress the reactivity of CuSe nuclei and Zn monomers, promoting ZnSe growth outside CuSe nuclei rather than form ZnSe nuclei separately. With increased ZnSe QD size, the conduction band and nearby trap state energy levels shift to higher energy sites, causing Cu:ZnSe QDs to have a much longer emission.

  11. Phosphine-free synthesis of high quality ZnSe, ZnSe/ZnS, and Cu-, Mn-doped ZnSe nanocrystals.

    Science.gov (United States)

    Shen, Huaibin; Wang, Hongzhe; Li, Xiaomin; Niu, Jin Zhong; Wang, Hua; Chen, Xia; Li, Lin Song

    2009-12-21

    High quality zinc blende ZnSe and ZnSe/ZnS core/shell nanocrystals have been synthesized by two converse injection methods (i.e. zinc precursor injection or selenium precursor injection) when Se-ODE complex was chosen as the phosphine-free selenium precursor. Absorption spectroscopy, fluorescence spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM) were used to characterize the as-synthesized ZnSe and ZnSe/ZnS nanocrystals. The quality of the as-prepared ZnSe nanocrystals reached the same high level compared with the method using phosphine selenium precursors since the quantum yields were between 40 and 60% and photoluminescence (PL) full width at half-maximum (FWHM) was well controlled between 14 and 17 nm. The parameter window for the growth of high quality ZnSe nanocrystals was found to be much broader and monodisperse ZnSe nanocrystals were synthesized successfully even when the reaction temperature was set as low as 240 degrees C. As cores, such zinc blende ZnSe nanocrystals were also used to synthesize ZnSe/ZnS core/shell nanocrystals with high fluorescence quantum yields of 70%. Cu(2+) or Mn(2+) doped ZnSe nanocrystals were also synthesized by simply modifying this phosphine-free method. The emission range has been extended to 500 and 600 nm with the use of Cu(2+) and Mn(2+) dopants compared with the emission coverage of ZnSe at around 400 nm. This is the first totally "green approach" (i.e. phosphine-free synthesis) for the synthesis of high quality ZnSe, ZnSe/ZnS, and Cu(2+) or Mn(2+) doped ZnSe nanocrystals.

  12. Organic/inorganic nanocomposites of ZnO/CuO/chitosan with improved properties

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Xingfa, E-mail: xingfamazju@aliyun.com [School of Environmental and Material Engineering, Center of Advanced Functional Materials, Yantai University, Yantai, 264005 (China); State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou, 310027 (China); Zhang, Bo; Cong, Qin; He, Xiaochun; Gao, Mingjun [School of Environmental and Material Engineering, Center of Advanced Functional Materials, Yantai University, Yantai, 264005 (China); Li, Guang [National Laboratory of Industrial Control Technology, Institute of Cyber-Systems and Control, Zhejiang University, Hangzhou, 310027 (China)

    2016-08-01

    To extend the visible light response of ZnO, ZnO/CuO heterostructured nanocomposite was synthesized by a hydrothermal approach. At the same time, chitosan (Ch) is considered as a very promising natural polymer. It holds not only abundant resource and low cost, but also has excellent adsorption properties to a broad range of organic pollutants and some heavy metal ions. To improve the adsorption properties of ZnO/CuO nanocomposite, ZnO/CuO/chitosan organic-inorganic composites were prepared with precipitation method. The as-prepared nanocomposites were characterized by TEM (Transmission electron microscopy), SAED pattern (Selected Area Electron Diffraction), SEM (scanning electron microscopy), UV–Vis (Ultraviolet–visible spectroscopy), PL (Photoluminescence), XRD (X-ray diffraction), TGA (Thermo Gravimetric Analyzer), Fourier transform infrared spectroscopy spectra (FTIR) et al. To examine the surface and interface properties of nanocomposites, chemical prototype sensor arrays were constructed based on ZnO, ZnO/CuO, ZnO/Cu{sub 2}O, ZnO/CuO/chitosan, ZnO/Cu{sub 2}O/chitosan nanocomposites and QCM (quartz crystal microbalance) arrays devices. The adsorption response behaviors of the sensor arrays to some typical volatile compounds were examined under similar conditions. The results indicated that with comparison to ZnO nanostructure, the ZnO/CuO nanocomposite exhibited enhanced adsorption properties to some typical volatile compounds greatly, and the adsorption properties of ZnO/CuO/chitosan are much better than that of ZnO/CuO nanocomposite. The adsorption of ZnO/CuO system is super to that of ZnO/Cu{sub 2}O. Therefore, ZnO/CuO/chitosan nanocomposite not only showed broadening visible light response, but also possessed of excellent adsorption properties, and has good potential applications in photocatalysts, chemical sensors, biosensors, self-cleaning coating fields et al. - Highlights: • ZnO/CuO nanocomposites exhibited good response in near whole visible

  13. CuZn Alloy- Based Electrocatalyst for CO2 Reduction

    KAUST Repository

    Alazmi, Amira

    2014-06-01

    ABSTRACT CuZn Alloy- Based Electrocatalyst for CO2 Reduction Amira Alazmi Carbon dioxide (CO2) is one of the major greenhouse gases and its emission is a significant threat to global economy and sustainability. Efficient CO2 conversion leads to utilization of CO2 as a carbon feedstock, but activating the most stable carbon-based molecule, CO2, is a challenging task. Electrochemical conversion of CO2 is considered to be the beneficial approach to generate carbon-containing fuels directly from CO2, especially when the electronic energy is derived from renewable energies, such as solar, wind, geo-thermal and tidal. To achieve this goal, the development of an efficient electrocatalyst for CO2 reduction is essential. In this thesis, studies on CuZn alloys with heat treatments at different temperatures have been evaluated as electrocatalysts for CO2 reduction. It was found that the catalytic activity of these electrodes was strongly dependent on the thermal oxidation temperature before their use for electrochemical measurements. The polycrystalline CuZn electrode without thermal treatment shows the Faradaic efficiency for CO formation of only 30% at applied potential ~−1.0 V vs. RHE with current density of ~−2.55 mA cm−2. In contrast, the reduction of oxide-based CuZn alloy electrode exhibits 65% Faradaic efficiency for CO at lower applied potential about −1.0 V vs. RHE with current density of −2.55 mA cm−2. Furthermore, stable activity was achieved over several hours of the reduction reaction at the modified electrodes. Based on electrokinetic studies, this improvement could be attributed to further stabilization of the CO2•− on the oxide-based Cu-Zn alloy surface.

  14. Aging behavior and fatigue crack propagation of high Zn-containing Al-Zn-Mg-Cu alloys with zinc variation

    National Research Council Canada - National Science Library

    Kai Wen Yunqiang Fan Guojun Wang Longbing Jin Xiwu Li Zhihui Li Yongan Zhang Baiqing Xiong

    2017-01-01

    In the present work, the influence of two-step aging treatments on hardness, electrical conductivity and mechanical properties of two high Zn-containing Al-Zn-Mg-Cu alloys with zinc content variation...

  15. Effect of Heat Treatment on the Microstructure and Corrosion Resistance of Cu-Zn Alloy

    Institute of Scientific and Technical Information of China (English)

    Xu Tao; Zhang Hailong; Xiao Nianxin; Zhao Xiangling

    2007-01-01

    The microstructure of Cu-Zn alloy with different heat treatment conditions in 3.5% NaCl + NH3 solution were observed, and the average corrosion rates and electrochemical data of Cu-Zn alloy were measured, as well as the effect of heat treatment on microstructure and corrosion resistance of Cu-Zn alloy was analyzed. The results show that the microstructure of Cu-Zn alloy has been changed due to the heat treatment. As a results, the better corrosion resistance can be obtained for the Cu-Zn alloy quenched from 900℃ for 0.5h followed by tempered at 100℃ for 2h.

  16. Colloidal synthesis of Cu-ZnO and Cu@CuNi-ZnO hybrid nanocrystals with controlled morphologies and multifunctional properties

    Science.gov (United States)

    Zeng, Deqian; Gong, Pingyun; Chen, Yuanzhi; Zhang, Qinfu; Xie, Qingshui; Peng, Dong-Liang

    2016-06-01

    Metal-semiconductor hybrid nanocrystals have received extensive attention owing to their multiple functionalities which can find wide technological applications. The utilization of low-cost non-noble metals to construct novel metal-semiconductor hybrid nanocrystals is important and meaningful for their large-scale applications. In this study, a facile solution approach is developed for the synthesis of Cu-ZnO hybrid nanocrystals with well-controlled morphologies, including nanomultipods, core-shell nanoparticles, nanopyramids and core-shell nanowires. In the synthetic strategy, Cu nanocrystals formed in situ serve as seeds for the heterogeneous nucleation and growth of ZnO, and it eventually forms various Cu-ZnO hetero-nanostructures under different reaction conditions. These hybrid nanocrystals possess well-defined and stable heterostructure junctions. The ultraviolet-visible-near infrared spectra reveal morphology-dependent surface plasmon resonance absorption of Cu and the band gap absorption of ZnO. Furthermore, we construct a novel Cu@CuNi-ZnO ternary hetero-nanostructure by incorporating the magnetic metal Ni into the pre-synthesized colloidal Cu nanocrystals. Such hybrid nanocrystals possess a magnetic Cu-Ni intermediate layer between the ZnO shell and the Cu core, and exhibit ferromagnetic/superparamagnetic properties which expand their functionalities. Finally, enhanced photocatalytic activities are observed in the as-prepared non-noble metal-ZnO hybrid nanocrystals. This study not only provides an economical way to prepare high-quality morphology-controlled Cu-ZnO hybrid nanocrystals for potential applications in the fields of photocatalysis and photovoltaic devices, but also opens up new opportunities in designing ternary non-noble metal-semiconductor hybrid nanocrystals with multifunctionalities.Metal-semiconductor hybrid nanocrystals have received extensive attention owing to their multiple functionalities which can find wide technological applications

  17. Classification of lattice defects in the kesterite Cu2ZnSnS4 and Cu2ZnSnSe4 earth-abundant solar cell absorbers.

    Science.gov (United States)

    Chen, Shiyou; Walsh, Aron; Gong, Xin-Gao; Wei, Su-Huai

    2013-03-20

    The kesterite-structured semiconductors Cu2ZnSnS4 and Cu2ZnSnSe4 are drawing considerable attention recently as the active layers in earth-abundant low-cost thin-film solar cells. The additional number of elements in these quaternary compounds, relative to binary and ternary semiconductors, results in increased flexibility in the material properties. Conversely, a large variety of intrinsic lattice defects can also be formed, which have important influence on their optical and electrical properties, and hence their photovoltaic performance. Experimental identification of these defects is currently limited due to poor sample quality. Here recent theoretical research on defect formation and ionization in kesterite materials is reviewed based on new systematic calculations, and compared with the better studied chalcopyrite materials CuGaSe2 and CuInSe2 . Four features are revealed and highlighted: (i) the strong phase-competition between the kesterites and the coexisting secondary compounds; (ii) the intrinsic p-type conductivity determined by the high population of acceptor CuZn antisites and Cu vacancies, and their dependence on the Cu/(Zn+Sn) and Zn/Sn ratio; (iii) the role of charge-compensated defect clusters such as [2CuZn +SnZn ], [VCu +ZnCu ] and [ZnSn +2ZnCu ] and their contribution to non-stoichiometry; (iv) the electron-trapping effect of the abundant [2CuZn +SnZn ] clusters, especially in Cu2ZnSnS4. The calculated properties explain the experimental observation that Cu poor and Zn rich conditions (Cu/(Zn+Sn) ≈ 0.8 and Zn/Sn ≈ 1.2) result in the highest solar cell efficiency, as well as suggesting an efficiency limitation in Cu2ZnSn(S,Se)4 cells when the S composition is high. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Molecular characterization and oxidative stress response of an intracellular Cu/Zn superoxide dismutase (CuZnSOD) of the whitefly, Bemisia tabaci.

    Science.gov (United States)

    Li, Jun-Min; Su, Yun-Lin; Gao, Xian-Long; He, Jiao; Liu, Shu-Sheng; Wang, Xiao-Wei

    2011-07-01

    Superoxide dismutases (SODs) are important for the survival of insects under environmental and biological stresses; however, little attention has been devoted to the functional characterization of SODs in whitefly. In this study, an intracellular copper/zinc superoxide dismutase of whitefly (Bemisia tabaci) (Bt-CuZnSOD) was cloned. Sequence analysis indicated that the full length cDNA of Bt-CuZnSOD is of 907 bp with a 471 bp open reading frame encoding 157 amino acids. The deduced amino acid sequence shares common consensus patterns with the CuZnSODs of various vertebrate and invertebrate animals. Phylogenetic analysis revealed that Bt-CuZnSOD is grouped together with intracellular CuZnSODs. Bt-CuZnSOD was then over-expressed in E. coli and purified using GST purification system. The enzymatic activity of purified Bt-CuZnSOD was assayed under various temperatures. When whiteflies were exposed to low (4°C) and high (40°C) temperatures, the in vivo activity of Bt-CuZnSOD was significantly increased. Furthermore, we measured the activities of several antioxidant enzymes, including SOD, catalase and peroxidase, in the whitefly after transferring the whitefly from cotton to tobacco (an unfavorable host plant). We found that the activity of SOD increased rapidly on tobacco plant. Taken together, these results suggest that the Bt-CuZnSOD plays a major role in protecting the whitefly against various stress conditions.

  19. Interfacial Phenomena in Al/Al, Al/Cu, and Cu/Cu Joints Soldered Using an Al-Zn Alloy with Ag or Cu Additions

    Science.gov (United States)

    Pstruś, Janusz; Gancarz, Tomasz

    2014-05-01

    The studies of soldered joints were carried out in systems: Al/solder/Al, Al/solder/Cu, Cu/solder/Cu, where the solder was (Al-Zn)EUT, (Al-Zn)EUT with 0.5, 1.0, and 1.5 at.% of Ag and (Al-Zn)EUT with 0.5, 1.0, and 1.5 at.% of Cu addition. Brazing was performed at 500 °C for 3 min. The EDS analysis indicated that the composition of the layers starting from the Cu pad was CuZn, Cu5Zn8, and CuZn4, respectively. Wetting tests were performed at 500 °C for 3, 8, 15, and 30 min, respectively. Thickness of the layers and their kinetics of growth were measured based on the SEM micrographs. The formation of interlayers was not observed from the side of Al pads. On the contrary, dissolution of the Al substrate and migration of Al-rich particles into the bulk of the solder were observed.

  20. Dynamic Behavior of CuZn Nanoparticles under Oxidizing and Reducing Conditions

    DEFF Research Database (Denmark)

    Holse, Christian; Elkjær, Christian Fink; Nierhoff, Anders Ulrik Fregerslev;

    2015-01-01

    The oxidation and reduction of CuZn nanoparticles was studied using X-ray photoelectron spectroscopy (XPS) and in situ transmission electron microscopy (TEM). CuZn nanoparticles with a narrow size distribution were produced with a gas-aggregation cluster source in conjunction with mass......-filtration. A direct comparison between the spatially averaged XPS information and the local TEM observations was thus made possible. Upon oxidation in O2, the as-deposited metal clusters transform into a polycrystalline cluster consisting of separate CuO and ZnO nanocrystals. Specifically, the CuO is observed...... to segregate to the cluster surface and partially cover the ZnO nanocrystals. Upon subsequent reduction in H2 the CuO converts into metallic Cu with ZnO nanocrystal covering their surface. In addition, a small amount of metallic Zn is detected suggesting that ZnO is reduced. It is likely that Zn species can...

  1. Electron paramagnetic resonance in Cu-doped ZnO

    Science.gov (United States)

    Buchheit, R.; Acosta-Humánez, F.; Almanza, O.

    2016-04-01

    In this work, ZnO and Cu-doped ZnO nanoparticles (Zn1-xCuxO, x = 3%), with a calcination temperature of 500∘C were synthesized using the sol-gel method. The particles were analyzed using atomic absorption spectroscopy (AAS), X-ray diffraction (XRD) and electron paramagnetic resonance (EPR) at X-band, measurement in a temperature range from 90 K to room temperature. AAS confirmed a good correspondence between the experimental doping concentration and the theoretical value. XRD reveals the presence of ZnO phase in hexagonal wurtzite structure and a nanoparticle size for the samples synthesized. EPR spectroscopy shows the presence of point defects in both samples with g-values of g = 1.959 for shallow donors and g = 2.004 for ionized vacancies. It is important when these materials are required have been used as catalysts, as suggested that it is not necessary prepare them at higher temperature. A simulation of the Cu EPR signal using an anisotropic spin Hamiltonian was performed and showed good coincidence with the experimental spectra. It was shown that Cu2+ ions enter interstitial octahedral sites of orthorhombic symmetry in the wurtzite crystal structure. Temperature dependence of the EPR linewidth and signal intensity shows a paramagnetic behavior of the sample in the measurement range. A Néel temperature TN = 78 ± 19 K was determined.

  2. Synthesis of highly non-stoichiometric Cu2ZnSnS4 nanoparticles with tunable bandgaps

    Science.gov (United States)

    Hamanaka, Yasushi; Oyaizu, Wataru; Kawase, Masanari; Kuzuya, Toshihiro

    2017-01-01

    Non-stoichiometric Cu2ZnSnS4 nanoparticles with average diameters of 4-15 nm and quasi-polyhedral shape were successfully synthesized by a colloidal method. We found that a non-stoichiometric composition of Zn to Cu in Cu2ZnSnS4 nanoparticles yielded a correlation where Zn content increased with a decrease in Cu content, suggesting formation of lattice defects relating to Cu and Zn, such as a Cu vacancy (VCu), antisite with Zn replacing Cu (ZnCu), and/or defect cluster of VCu and ZnCu. The bandgap energy of Cu2ZnSnS4 nanoparticles systematically varies between 1.56 and 1.83 eV depending on the composition ratios of Cu and Zn, resulting in a wider bandgap for Cu-deficient Cu2ZnSnS4 nanoparticles. These characteristics can be ascribed to the modification in electronic band structures due to formation of VCu and ZnCu on the analogy of ternary copper chalcogenide, chalcopyrite CuInSe2, in which the top of the valence band shifts downward with decreasing Cu contents, because much like the structure of CuInSe2, the top of the valence band is composed of a Cu 3 d orbital in Cu2ZnSnS4.

  3. Fatigue crack behavior on a Cu-Zn-Al SMA

    Directory of Open Access Journals (Sweden)

    V. Di Cocco

    2014-10-01

    Full Text Available In recent years, mechanical property of many SMA has improved in order to introduce these alloys in specific field of industry. Main examples of these alloys are the NiTi, Cu-Zn-Al and Cu-Al-Ni which are used in many fields of engineering such as aerospace or mechanical systems. Cu-Zn-Al alloys are characterized by good shape memory properties due to a bcc disordered structure stable at high temperature called β-phase, which is able to change by means of a reversible transition to a B2 structure after appropriate cooling, and reversible transition from B2 secondary to DO3 order, under other types of cooling. In β-Cu-Zn-Al shape memory alloys, the martensitic transformation is not in equilibrium at room temperature. It is therefore often necessary to obtain the martensitic structure, using a thermal treatment at high temperature followed by quenching. The martensitic phases can be either thermally-induced spontaneous transformation, or stressinduced, or cooling, or stressing the β- phase. Direct quenching from high temperatures to the martensite phase is the most effective because of the non-diffusive character of the transformation. The martensite inherits the atomic order from the β-phase. Precipitation of many kinds of intermetallic phases is the main problem of treatment on cu-based shape memory alloy. For instance, a precipitation of α-phase occurs in many low aluminum copper based SMA alloy and presence of α-phase implies a strong degradation of shape recovery. However, Cu-Zn-Al SMA alloys characterized by aluminum contents less than 5% cover a good cold machining and cost is lower than traditional NiTi SMA alloys. In order to improve the SMA performance, it is always necessary to identify the microstructural changing in mechanical and thermal conditions, using X-Ray analyses. In this work a Cu-Zn-Al SMA alloy obtained in laboratory has been microstructurally and metallographically characterized by means of X-Ray diffraction and Light

  4. First-principles study of defect formation in the photovoltaic semiconductors Cu2GeS3 and Cu2ZnGeS4 for comparison with Cu2SnS3, Cu2ZnSnS4, and CuInSe2

    Science.gov (United States)

    Nishihara, Hironori; Maeda, Tsuyoshi; Shigemi, Akio; Wada, Takahiro

    2017-04-01

    The formation energies of neutral Cu, Ge, and S vacancies in monoclinic Cu2GeS3 and those of neutral Cu, Zn, Ge, and S vacancies in kesterite-type Cu2ZnGeS4 were evaluated by first-principles pseudopotential calculations using plane-wave basis functions. The calculations were performed at typical points in a schematic ternary phase diagram of a Cu-Ge-S system for Cu2GeS3 and in Cu-(Zn1/2Ge1/2)-S and Cu29S16-ZnS-GeS2 pseudoternary phase diagrams for Cu2ZnGeS4. The results have been compared with those for Cu2SnS3, Cu2ZnSnS4, and CuInSe2 calculated with the same version of the CASTEP program code. The results indicate that Cu vacancies are easily formed in Cu2GeS3 and Cu2ZnGeS4 under the Cu-poor condition as in the cases of Cu2SnS3, Cu2ZnSnS4, and CuInSe2, suggesting that Cu2GeS3 and Cu2ZnGeS4 are also preferable p-type absorber materials for thin-film solar cells. Desirable preparation conditions of these thin films for photovoltaic application are discussed using the calculated formation energies of antisite defects.

  5. Corrosion Resistance of Zn and Cu Coated Steel Pipes as a Substitute for Cu Pipe in an Air Conditioner System

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Jae Gyeong; Park, Chan Jin; Hong, Sung Kil [Chonnam National University, Gwangju (Korea, Republic of)

    2009-02-15

    We investigated the corrosion resistance of Zn and Cu coated steel pipes as a substitute for Cu pipe in an air-conditioner system. In addition, the galvanic corrosion tendency between two dissimilar metal parts was studied. The corrosion resistance of the Cu electroplated steel was similar to that of Cu, while the corrosion rate of the Zn electro-galvanized and the galvalume (Zn-55 % Al) coated steels was much higher and not suitable for Cu substitute in artificial sea water and acidic rain environments. Furthermore, the galvanic difference between Cu electroplated steel and Cu was so small that the Cu coated steel pipe can be used as a substitute for Cu pipe in an air-conditioner system.

  6. The Brittleness Of Zn-Cu-Ti Sheet Alloys

    Directory of Open Access Journals (Sweden)

    Boczkal G.

    2015-09-01

    Full Text Available At temperatures below 5°C, the ductility of ZnCuTi alloy sheets is observed to suffer a drastic drop in direction transverse to the rolling direction. Studies have shown that the critical temperature at which this phenomenon occurs is strongly dependent on the alloy structure and parameters of the sheet metal production process. Quite important is also the role of micro-inhomogeneity arising in the chemical composition of the alloy matrix, directly related with the structure of intermetallic precipitates containing Cu and Ti.

  7. Effect of Cu/(Zn+Sn) ratio on the properties of co-evaporated Cu{sub 2}ZnSnSe{sub 4} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Suresh Babu, G.; Kishore Kumar, Y.B.; Uday Bhaskar, P.; Raja Vanjari, Sundara [Sri Venkateswara University, Solar Energy Laboratory, Department of Physics, S.V.U. Campus, Tirupati 517 502 (India)

    2010-02-15

    The effect of Cu/(Zn+Sn) ratio on the properties of Cu{sub 2}ZnSnSe{sub 4} (CZTSe) thin films is investigated. CZTSe thin films with Cu/(Zn+Sn) ratio in the range 0.85-1.15 are deposited using 4-source co-evaporation technique onto glass substrates held at a substrate temperature T{sub s}=623 K and post-deposition annealed at T{sub pa}=723 K for 1 h in the selenium atmosphere. Powder X-ray diffraction (XRD) patterns reveal that CZTSe films deposited with Cu/(Zn+Sn) ratio in the range 0.90-1.10 are single phase and polycrystalline. CZTSe films, deposited with Cu/(Zn+Sn) ratio of 0.85 contain ZnSe as secondary phase and films with ratio of 1.15 contain Cu{sub 2-X}Se as the secondary phase. The films are found to exhibit kesterite structure. Band gap of the films is found to increase with decrease in Cu/(Zn+Sn) ratio. Electrical resistivity of the films is found to lie in the range 0.02-23-{omega}-cm depending on Cu/(Zn+Sn) ratio. (author)

  8. Synthesis of CuS/ZnO Nanocomposite and Its Visible-Light Photocatalytic Activity

    OpenAIRE

    Lianping Zhu; Min Zheng; Juan Lu; Mengfei Xu; Hyo Jin Seo

    2014-01-01

    The CuS/ZnO nanocomposite was successfully synthesized by a simple mechanical method, without adding any surfactants. TEM images showed that CuS existed in the nanocomposite and the size of CuS/ZnO nanocomposite particle was around 35 nm. CuS worked as an electron absorber in the nanocomposite, which was beneficial for the improvement of photocatalysis of ZnO. It was also proved by the experiments performed under the visible light irradiation that CuS could help ZnO degrade methylene blue (MB...

  9. Tolerance of spermatogonia to oxidative stress is due to high levels of Zn and Cu/Zn superoxide dismutase.

    Directory of Open Access Journals (Sweden)

    Fritzie T Celino

    Full Text Available BACKGROUND: Spermatogonia are highly tolerant to reactive oxygen species (ROS attack while advanced-stage germ cells such as spermatozoa are much more susceptible, but the precise reason for this variation in ROS tolerance remains unknown. METHODOLOGY/PRINCIPAL FINDINGS: Using the Japanese eel testicular culture system that enables a complete spermatogenesis in vitro, we report that advanced-stage germ cells undergo intense apoptosis and exhibit strong signal for 8-hydroxy-2'-deoxyguanosine, an oxidative DNA damage marker, upon exposure to hypoxanthine-generated ROS while spermatogonia remain unaltered. Activity assay of antioxidant enzyme, superoxide dismutase (SOD and Western blot analysis using an anti-Copper/Zinc (Cu/Zn SOD antibody showed a high SOD activity and Cu/Zn SOD protein concentration during early spermatogenesis. Immunohistochemistry showed a strong expression for Cu/Zn SOD in spermatogonia but weak expression in advanced-stage germ cells. Zn deficiency reduced activity of the recombinant eel Cu/Zn SOD protein. Cu/Zn SOD siRNA decreased Cu/Zn SOD expression in spermatogonia and led to increased oxidative damage. CONCLUSIONS/SIGNIFICANCE: These data indicate that the presence of high levels of Cu/Zn SOD and Zn render spermatogonia resistant to ROS, and consequently protected from oxidative stress. These findings provide the biochemical basis for the high tolerance of spermatogonia to oxidative stress.

  10. Production of hydrogen from methanol over Cu/ZnO and Cu/ZnO/Al2O3 catalysts prepared by homogeneous precipitation : Steam reforming and oxidative steam reforming

    OpenAIRE

    2006-01-01

    Two series of Cu/ZnO and Cu/ZnO/Al2O3 catalysts with varying Cu/Zn ratio have been prepared by the homogeneous precipitation (hp) method using urea hydrolysis. Steam reforming and oxidative steam reforming of methanol were performed using the hp-Cu/Zn-based catalysts for catalytic production of hydrogen. The hp-Cu/ZnO/Al2O3 catalyst showed a higher activity than the hp-Cu/ZnO catalysts. In both cases, the catalytic activity was well correlated with the surface area of Cu metal, and the maximu...

  11. [Bioconcentration and translocation of Cu and Zn by Brassica sinensis L. planted in high Cu and Zn contaminated pig manure-applied soils].

    Science.gov (United States)

    Zhang, Yan; Cui, Xiao-yong; Luo, Wei; Shi, Peng; Lü, Yong-long

    2011-05-01

    In recent years, Cu and Zn have been widely used in pig fodders in large-scale animal feeding, causing Cu and Zn contamination in soils and effecting plants in land application of pig manure. It is of great concern to the world that pig manure is used in the dose greater than the organic fertilizer criterion. It is very important to clarify bioconcentration and translocation of Cu and Zn in vegetables in order to assess human health risk of these heavy metals accumulated in soil and to safely produce vegetables. Bioconcentration and translocation of Cu and Zn by Brassica sinensis L. planted in pig manure-applied soils were studied using pot experiments. Pig manure with great concentrations of Cu and Zn (Cu = 1114.7 mg x kg(-1), Zn = 1496.8 mg x kg(-1)) were applied to soils at six rates, i.e., 0, 25, 50, 100, 200 and 500 t x hm(-2). The results indicate that the concentration of Zn was greater than that of Cu in both aboveground and underground parts of B. sinensis. Both Cu and Zn concentrations in the underground part were greater than those in upper-ground for every treatment. There were significant differences for both Cu and Zn concentrations in shoots between CK and the treatment with application rate above 50 t x hm(-2). Bioconcentration factor of Cu in B. sinensis increased with pig manure application rate from 0.11 to 0.17, while that of Zn decreased from 0.47 to 0.11. The proportion of Cu and Zn transported from roots to shoots decreased 25% and 38% with the increase of pig manure application, respectively. It indicates that pig manure application can reduce bioconcentration of Zn in B. sinensis, and build up Cu accumulation which leads to human health risk. The ratio of Zn:Cu in every part of B. sinensis decreased with manure application rate increment. This result prompted that uptake and translocation capacity discrepancy of Cu and Zn decreased with manure application rate increment in B. sinensis.

  12. Electronic structure and optical properties of Cu-doping and Zn vacancy impurities in ZnTe.

    Science.gov (United States)

    Li, Qing-Fang; Hu, Ge; She, Qing; Yao, Jing; Feng, Wen-Jiang

    2013-09-01

    The geometric structures of perfect ZnTe, that with Zn vacancy (Zn0.875Te), and Cu-doped ZnTe (Zn0.875Cu0.125Te) were optimized using the pseudopotential plane wave (PP-PW) method based on the density functional theory (DFT) within generalized gradient approximation (GGA). The cohesive energy, band structure, density of states, and Mulliken populations were calculated and discussed in detail. On the other hand, an accurate calculation of linear optical functions (the dielectric function, refraction index, reflectivity, conductivity function, and energy-loss spectrum) was performed. The results demonstrated that compared to the perfect ZnTe, the lattice parameters of Zn0.875Te and Zn0.875Cu0.125Te were changed and the cell volumes decreased to some extent due to the vacancy and introduction of impurity. A vacancy acceptor level and an acceptor impurity level were produced in Zn0.875Te and Zn0.875Cu0.125Te, respectively. By comparison, Cu doping in the ZnTe system is relatively stable while the monovacancy system is not.

  13. Metallothionein Zn(2+)- and Cu(2+)-clusters from first-principles calculations

    DEFF Research Database (Denmark)

    Greisen, Per Junior; Jespersen, Jakob Berg; Kepp, Kasper Planeta

    2012-01-01

    Detailed electronic structures of Zn(ii) and Cu(ii) clusters from metallothioneins (MT) have been obtained using density functional theory (DFT), in order to investigate how oxidative stress-caused Cu(ii) intermediates affect Zn-binding to MT and cooperatively lead to Cu(i)MT. The inferred accura...

  14. ZnO/Cu(InGa)Se.sub.2 solar cells prepared by vapor phase Zn doping

    Science.gov (United States)

    Ramanathan, Kannan; Hasoon, Falah S.; Asher, Sarah E.; Dolan, James; Keane, James C.

    2007-02-20

    A process for making a thin film ZnO/Cu(InGa)Se.sub.2 solar cell without depositing a buffer layer and by Zn doping from a vapor phase, comprising: depositing Cu(InGa)Se.sub.2 layer on a metal back contact deposited on a glass substrate; heating the Cu(InGa)Se.sub.2 layer on the metal back contact on the glass substrate to a temperature range between about 100.degree. C. to about 250.degree. C.; subjecting the heated layer of Cu(InGa)Se.sub.2 to an evaporant species from a Zn compound; and sputter depositing ZnO on the Zn compound evaporant species treated layer of Cu(InGa)Se.sub.2.

  15. Thermal Decomposition Studies of Layered Metal Hydroxynitrates (Metal: Cu, Zn, Cu/Co, and Zn/Co

    Directory of Open Access Journals (Sweden)

    Thimmasandra Narayan Ramesh

    2015-01-01

    Full Text Available Layered metal hydroxynitrates and mixed metal hydroxynitrates (copper/cobalt hydroxynitrates and zinc/cobalt hydroxynitrates at different mole ratios were synthesized by hydrolysis of urea and metal nitrates at 140°C. Layered metal hydroxyl nitrates derive their structure from brucite mineral and generally crystallize in hexagonal and monoclinic phases. Isothermal decomposition studies of Cu2(OH3(NO3, Co2(OH3(NO3, Cu1.5Co0.5(OH3(NO3, Cu1.34Co0.66(OH3(NO3, Zn5(OH8(NO32(H2O2, Zn3.75Co1.25(OH8(NO32(H2O2, and Zn3.35Co1.65(OH8(NO32(H2O2 samples were carried out at different intervals of temperature and the structural transformations during the process were monitored using powder X-ray diffractograms. Biphasic mixture of metal hydroxynitrate/metal oxide is observed in case of cobalt/zinc based layered hydroxynitrates, while copper hydroxynitrate or copper/cobalt metal hydroxynitrate decomposes in a single step. The decomposition temperatures of layered metal hydroxynitrates and mixed layered metal hydroxides depend on the method of preparation, their composition and the nature of metal ion, and their coordination.

  16. Atmospheric corrosion of Cu, Zn, and Cu-Zn alloys protected by self-assembled monolayers of alkanethiols

    Science.gov (United States)

    Hosseinpour, Saman; Forslund, Mattias; Johnson, C. Magnus; Pan, Jinshan; Leygraf, Christofer

    2016-06-01

    In this article results from earlier studies have been compiled in order to compare the protection efficiency of self-assembled monolayers (SAM) of alkanethiols for copper, zinc, and copper-zinc alloys exposed to accelerated indoor atmospheric corrosion conditions. The results are based on a combination of surface spectroscopy and microscopy techniques. The protection efficiency of investigated SAMs increases with chain length which is attributed to transport hindrance of the corrosion stimulators in the atmospheric environment, water, oxygen and formic acid, towards the copper surface. The transport hindrance is selective and results in different corrosion products on bare and on protected copper. Initially the molecular structure of SAMs on copper is well ordered, but the ordering is reduced with exposure time. Octadecanethiol (ODT), the longest alkanethiol investigated, protects copper significantly better than zinc, which may be attributed to the higher bond strength of Cu-S than of Zn-S. Despite these differences, the corrosion protection efficiency of ODT for the single phase Cu20Zn brass alloy is equally efficient as for copper, but significantly less for the heterogeneous double phase Cu40Zn brass alloy.

  17. Cu,Zn SOD in Shandong families with amyotrophic lateral sclerosis

    Institute of Scientific and Technical Information of China (English)

    GU Hong-yan; ZHANG Feng-zhen; JIANG Han-Ming; SUN Ling-Yun; ZAI Jing; ZHANG Yuan-ying

    2004-01-01

    Objective: To understand the relationship between Cu,Zn SOD and amyotrophic lateral sclerosis. Methods: The patients were clinically examined and classified according to the E1 Escorial Criteria, then we obtained blood samples from the patients for Cu,Zn SOD analysis and SOD assay. Amino acid analysis of Cu,Zn SOD were fully automated in instruments called amino acid analyzers. SOD assay was determined by cytochrome c method Results: Amino acid analysis of Cu,Zn SOD from patients with familial ALS was normal. The activity of Cu,Zn SOD was normal both in familial and sporadic form of ALS compared with normal person. Conclusion: Amyotrophic lateral sclerosis is not related to Cu,Zn SOD.

  18. Tensile behavior of Sn-0.7Cu with Zn addition at various deformation temperatures

    Institute of Scientific and Technical Information of China (English)

    Zhongbing LUO; Jie ZHAO; Junshan ZHANG; Lai WANG

    2011-01-01

    The tensile behavior of Sn-0.7Cu and Sn-0.7Cu-lZn was compared at various deformation temperatures. Refined microstructure and γ-CuZn particles were discovered with Zn addition. The strengths of Zn-containing solder were higher than that of Sn-0.7Cu at room and subzero temperatures. With the elevation of deformation temperature, they both decreased and they were nearly the same at 80 ℃. The works of fracture exhibited the similar evolution law. For Sn-0.7Cu solder, the elongation after fracture was smaller and the reduction of area was bigger than those of Sn-0.7Cu-1Zn. This shows that Zn addition improved the deformation stability, which is attributed to the modification of the microstructure. Dimples in fracture surface became smaller and shallower with the decreasing temperature. Ductile fracture was discovered in all the samples.

  19. Research of Interaction Between Zn Based Solders and Cu, Al Substrates

    Directory of Open Access Journals (Sweden)

    Prach Michal

    2014-06-01

    Full Text Available The paper deals with the study of interaction between Cu, Al substrates (purity 5N and ZnAl4, ZnAg6Al6 zinc solders for higher application temperatures. Soldering was performed with power ultrasound in the air without flux application at temperature 420 °C. Acting time of ultrasonic vibration was 3 s and ultrasound frequency was 40 kHz. Soldered joints were assessed by optical light microscopy and EDX microanalysis. Intermetallic layers (IM CuZn4 and Cu5Zn8 were formed at the Cu/ZnAl4 boundary. The βZn-αAl mechanical mixture was formed at the Al/ZnAl4 boundary. AgZn3 and Cu5Zn8 IM layers were formed at the Cu/ZnAg6Al6 boundary, and mechanical mixture of βZn-αAl and AgZn3 intermetallic mixture were formed at the boundary Al/ZnAg6Al6.

  20. Concentrative phenomenon of relative content ratios of Cu, Pb and Zn in soils

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    It is discovered that there is the concentrative phenomenon of relative content ratios of Cu, Pb and Zn in soil by studying their parageneous association in soil, meterites and rocks with the relative content ratios. This not only is helpful to understand the trends of Cu, Cd and Zn enriched and dispersed in the evolution course of earth matter, but also provide evidence for geochemical self-organization that there may be in the process of Cu, Pb and Zn translation and distribution.

  1. Detection of Cu2Zn5SnSe8 and Cu2Zn6SnSe9 phases in co-evaporated Cu2ZnSnSe4 thin-films

    Science.gov (United States)

    Schwarz, Torsten; Marques, Miguel A. L.; Botti, Silvana; Mousel, Marina; Redinger, Alex; Siebentritt, Susanne; Cojocaru-Mirédin, Oana; Raabe, Dierk; Choi, Pyuck-Pa

    2015-10-01

    Cu2ZnSnSe4 thin-films for photovoltaic applications are investigated using combined atom probe tomography and ab initio density functional theory. The atom probe studies reveal nano-sized grains of Cu2Zn5SnSe8 and Cu2Zn6SnSe9 composition, which cannot be assigned to any known phase reported in the literature. Both phases are considered to be metastable, as density functional theory calculations yield positive energy differences with respect to the decomposition into Cu2ZnSnSe4 and ZnSe. Among the conceivable crystal structures for both phases, a distorted zinc-blende structure shows the lowest energy, which is a few tens of meV below the energy of a wurtzite structure. A band gap of 1.1 eV is calculated for both the Cu2Zn5SnSe8 and Cu2Zn6SnSe9 phases. Possible effects of these phases on solar cell performance are discussed.

  2. Enhanced wetting of Cu on ZnO by migration of subsurface oxygen vacancies

    DEFF Research Database (Denmark)

    Beinik, Igor; Helström, Matti; Jensen, Thomas Nørregaard;

    2015-01-01

    is of utmost importance. The Cu/ZnO system is among the most investigated of such systems in model studies, but the presence of subsurface ZnO defects and their important role for adhesion on ZnO have been unappreciated so far. Here we reveal that the surface-directed migration of subsurface defects affects...... the Cu adhesion on polar ZnO(0001) in the technologically interesting temperature range up to 550 K. This leads to enhanced adhesion and ultimately complete wetting of ZnO(0001) by a Cu overlayer. On the basis of our experimental and computational results we demonstrate a mechanism which implies...

  3. Low temperature sintering of MgCuZn ferrite and its electrical and magnetic properties

    Indian Academy of Sciences (India)

    S R Murthy

    2001-08-01

    The low temperature sintering of MgCuZn ferrite was investigated using the usual ceramic method. The effect of Cu substitution on the properties of MgZn ferrites was also investigated and it was found that the densification of MgCuZn ferrite is dependent upon Cu concentration. The sintered ferrite with a density of 4.93 g/cm3 and electrical resistivity > 1011-cm was obtained for the ferrite with 12 mol% Cu at relatively low sintering temperature (910°C). The magnetic properties of the ferrites also improved by the Cu substitution. The chip inductors made of the ferrite fired at 910 C with 12 mol% Cu exhibited higher d.c. resistance. From these studies it is concluded that the good quality chip inductor can be obtained using the MgCuZn ferrites.

  4. The effect of Cu/Zn molar ratio on CO2 hydrogenation over Cu/ZnO/ZrO2/Al2O3 catalyst

    Science.gov (United States)

    Shaharun, Salina; Shaharun, Maizatul S.; Mohamad, Dasmawati; Taha, Mohd F.

    2014-10-01

    Catalytic hydrogenation of carbon dioxide (CO2) to methanol is an attractive way to recycle and utilize CO2. A series of Cu / ZnO / Al2O3/ZrO2 catalysts (CZAZ) containing different molar ratios of Cu/Zn were prepared by the co-precipitation method and investigated in a stirred slurry autoclave system. The catalysts were characterized by temperature-programmed reduction (TPR), field emission scanning electron microscopy-energy dispersive analysis (FESEM-EDX), X-ray diffraction (XRD) and N2 adsorption-desorption. Higher surface area, SABET values (42.6-59.9 m2/g) are recorded at low (1) and high (5) Cu/Zn ratios with the minimum value of 35.71 m2/g found for a Cu/Zn of 3. The reducibility of the metal oxides formed after calcination of catalyst samples was also affected due to change in metal-support interaction. At a low reaction temperature of 443 K, total gas pressure of 3.0 MPa and 0.1 g/mL of the CZAZ catalyst, the selectivity to methanol decreased as the Cu/Zn molar ratio increased, and the maximum selectivity of 67.73 was achieved at Cu/Zn molar ratio of 1. With a reaction time of 3h, the best performing catalyst was CZAZ75 with Cu/Zn molar ratio of 5 giving methanol yield of 79.30%.

  5. Elastocaloric effect in CuAlZn and CuAlMn shape memory alloys under compression.

    Science.gov (United States)

    Qian, Suxin; Geng, Yunlong; Wang, Yi; Pillsbury, Thomas E; Hada, Yoshiharu; Yamaguchi, Yuki; Fujimoto, Kenjiro; Hwang, Yunho; Radermacher, Reinhard; Cui, Jun; Yuki, Yoji; Toyotake, Koutaro; Takeuchi, Ichiro

    2016-08-13

    This paper reports the elastocaloric effect of two Cu-based shape memory alloys: Cu68Al16Zn16 (CuAlZn) and Cu73Al15Mn12 (CuAlMn), under compression at ambient temperature. The compression tests were conducted at two different rates to approach isothermal and adiabatic conditions. Upon unloading at a strain rate of 0.1 s(-1) (adiabatic condition) from 4% strain, the highest adiabatic temperature changes (ΔTad) of 4.0 K for CuAlZn and 3.9 K for CuAlMn were obtained. The maximum stress and hysteresis at each strain were compared. The stress at the maximum recoverable strain of 4.0% for CuAlMn was 120 MPa, which is 70% smaller than that of CuAlZn. A smaller hysteresis for the CuAlMn alloy was also obtained, about 70% less compared with the CuAlZn alloy. The latent heat, determined by differential scanning calorimetry, was 4.3 J g(-1) for the CuAlZn alloy and 5.0 J g(-1) for the CuAlMn alloy. Potential coefficients of performance (COPmat) for these two alloys were calculated based on their physical properties of measured latent heat and hysteresis, and a COPmat of approximately 13.3 for CuAlMn was obtained.This article is part of the themed issue 'Taking the temperature of phase transitions in cool materials'.

  6. Effect of Cu doping on the properties of ZnTe:Cu thin films and CdS/CdTe/ZnTe solar cells

    Science.gov (United States)

    Tang, J.; Mao, D.; Trefny, J. U.

    1997-02-01

    The effects of Cu doping concentration and post-deposition annealing treatment on the properties of ZnTe thin films were investigated in an effort to decrease the Cu doping concentration and improve the long-term stability of CdS/CdTe/ZnTe solar cells. The structural, compositional, and electrical properties were studied systematically using x-ray diffraction (XRD), electron microprobe, Hall effect and conductivity measurements. XRD measurements indicated that the crystalline phase of as-deposited and low-temperature annealed ZnTe films is dependent on Cu doping concentration. Low-Cu-doped films exhibited zincblende phase, whereas high-Cu-doped films showed wurtzite phase. After annealing at high temperature (⩾350 °C), all films exhibited zincblende structure. Electron probe microanalysis revealed a deficiency of cations in low-Cu-doped films and an excess of cations in high-Cu-doped films. Hall effect measurements revealed a dependence of hole mobility on Cu doping concentration with the highest mobility (20 cm2/Vṡs) obtained at a low Cu concentration. Carrier concentrations higher than mid-1016cm-3 were obtained at a Cu concentration of 2 at. % and relatively low annealing temperatures. Studies of the activation energy of dark conductivity suggested that intrinsic defects (e.g., Zn vacancies) are the dominant acceptors for Cu concentrations lower than 4.5 at. %. Finally, ZnTe films with Cu concentrations as low as 1 at. % were used successfully as a back contact layer in CdTe based solar cells. Fill factors over 0.70 were obtained using ZnTe films of low Cu concentrations.

  7. Interaction of Copper in CuZn-Superoxide Dismutase With Histidine

    Institute of Scientific and Technical Information of China (English)

    胡皆汉; 舒占永

    1994-01-01

    The interaction of CuZn-superoxide dismutase ( CuZn-SOD ) with the external histidine in aqueous solution has been studied in this work by ESR and NMR. It is found that the Cu(Ⅱ) of CuZn-SOD makes an exchanging interaction with the external substance in aqueous solution. Unlike in solid state, the Cu(Ⅱ) forms complex with external histidine, and keeps a motional equilibrium between the active centers and the complexes. Enzyme activity is also affected by this interaction. Some other amino acids are also discussed in this paper.

  8. S, Zn, Cr, Cu and Fe changes during fluvial sediments oxidation Transformaciones del S, Zn, Cr, Cu y Fe en sedimentos fluviales durante el proceso de secado

    Directory of Open Access Journals (Sweden)

    María Pía Di Nanno

    2009-12-01

    Full Text Available Acidification of dredged sediments which have been disposed on land is highly dependent on redox shifts. The aim of the present work was to assess changes in sulphur, metal speciation (Zn, Fe, Cr y Cu and acidity caused by a polluted sediment oxidation event. Sediments were dessicated under controlled conditions and sulphide compounds (acid volatile sulphides-AVS- and sulphate, pH and neutralization potential were measured through time during 36 days. Zinc, Cu, Cr and Fe speciation (BCR metal sequential extraction procedure were measured at the beginning of the experiment and at day 22. An acid-base equilibrium method based on the BCR procedure was employed to assess the sediment acidification risk. Some of the re-suspension experiments were inoculated with an Acidithiobacillus ferrooxidans strain to assess biological catalysis on sulphide oxidation. Acid-base equilibrium results indicated the sediment sample had a significant acidification potential. Oxidation increased sulphate levels (56 to 2300 mg S kg-¹ in the desiccation experiment with a temporal evolution adjusted by a logistic model, and a 2100 to 3000 mg SO4 -² L-¹ increase for the resuspension experiments. Sulphide oxidation rates varied between 0 to 3.1.10-9 mg O2 kg-¹ s-¹ for the drying sediment. Zinc changes could be explained partially by ZnS conversion to ZnSO4 during oxidation. Iron reduction could be attributed to an increase in Fe oxides crystallinity. Acid-base equilibrium for the sample indicated it was a potentially acid-generating material. Zinc increased its bioavailability during drying and was the only metal that appeared in significant amounts in solution during re-suspension. Land-filling with dredged sediments could present increased metals bioavailability problems despite having an important and effective neutralization potential.La evaluación de los riesgos de acidificación por deposición de sedimentos dragados en superficie es muy dependiente de los

  9. Quantifying point defects in Cu2ZnSn(S,Se)4 thin films using resonant x-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Stone, Kevin H. [Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA; Christensen, Steven T. [National Renewable Energy Laboratory, Golden, Colorado 80401, USA; Harvey, Steven P. [National Renewable Energy Laboratory, Golden, Colorado 80401, USA; Teeter, Glenn [National Renewable Energy Laboratory, Golden, Colorado 80401, USA; Repins, Ingrid L. [National Renewable Energy Laboratory, Golden, Colorado 80401, USA; Toney, Michael F. [Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA

    2016-10-17

    Cu 2ZnSn(S,Se)4 is an interesting, earth abundant photovoltaic material, but has suffered from low open circuit voltage. To better understand the film structure, we have measured resonant x-ray diffraction across the Cu and Zn K-edges for the device quality thin films of Cu 2ZnSnS4 (8.6% efficiency) and Cu 2ZnSn(S,Se)4 (3.5% efficiency). This approach allows for the confirmation of the underlying kesterite structure and quantification of the concentration of point defects and vacancies on the Cu, Zn, and Sn sublattices. Rietveld refinement of powder diffraction data collected at multiple energies is used to determine that there exists a high level of Cu Zn and Zn Cu defects on the 2c and 2d Wyckoff positions. We observe a significantly lower concentration of Zn Sn defects and Cu or Zn vacancies.

  10. Quantifying point defects in Cu2ZnSn(S,Se)4 thin films using resonant x-ray diffraction

    Science.gov (United States)

    Stone, Kevin H.; Christensen, Steven T.; Harvey, Steven P.; Teeter, Glenn; Repins, Ingrid L.; Toney, Michael F.

    2016-10-01

    Cu2ZnSn(S,Se)4 is an interesting, earth abundant photovoltaic material, but has suffered from low open circuit voltage. To better understand the film structure, we have measured resonant x-ray diffraction across the Cu and Zn K-edges for the device quality thin films of Cu2ZnSnS4 (8.6% efficiency) and Cu2ZnSn(S,Se)4 (3.5% efficiency). This approach allows for the confirmation of the underlying kesterite structure and quantification of the concentration of point defects and vacancies on the Cu, Zn, and Sn sublattices. Rietveld refinement of powder diffraction data collected at multiple energies is used to determine that there exists a high level of CuZn and ZnCu defects on the 2c and 2d Wyckoff positions. We observe a significantly lower concentration of ZnSn defects and Cu or Zn vacancies.

  11. Preparation of Cu2ZnSnS4 thin films by hybrid sputtering

    Science.gov (United States)

    Tanaka, Tooru; Nagatomo, Takeshi; Kawasaki, Daisuke; Nishio, Mitsuhiro; Guo, Qixin; Wakahara, Akihiro; Yoshida, Akira; Ogawa, Hiroshi

    2005-11-01

    In order to fabricate Cu2ZnSnS4 thin films, hybrid sputtering system with two sputter sources and two effusion cells is used. The Cu2ZnSnS4 films are fabricated by the sequential deposition of metal elements and annealing in S flux, varying the substrate temperature. The Cu2ZnSnS4 films with stoichiometric composition are obtained at the substrate temperature up to 400 °C, whereas the film composition becomes quite Zn-pool at the substrate temperature above 450 °C. The Cu2ZnSnS4 film shows p-type conductivity, and the optical absorption coefficient and the band gap of the Cu2ZnSnS4 film prepared in this experiment are suitable for fabricating a thin film solar cell.

  12. X-ray excited ZnS:Cu,Co afterglow nanoparticles for photodynamic activation

    Science.gov (United States)

    Ma, Lun; Zou, Xiaoju; Bui, Brian; Chen, Wei; Song, Kwang Hyun; Solberg, Timothy

    2014-07-01

    Copper and cobalt co-doped ZnS (ZnS:Cu,Co) afterglow nanoparticles were conjugated to photosensitizer tetrabromorhodamine-123 (TBrRh123) and efficient energy transfer from the nanoparticles to TBrRh123 was observed. In addition to their X-ray excited luminescence, the ZnS:Cu,Co nanoparticles also show long lasting afterglow, which continuously serve as a light source for photodynamic therapy (PDT) activation. Compared to TBrRh123 or ZnS:Cu,Co alone, the ZnS:Cu,Co-TBrRh123 conjugates show low dark toxicity but high X-ray induced toxicity to human prostate cancer cells. The results indicate that the ZnS:Cu,Co afterglow nanoparticles have a good potential for PDT activation.

  13. ZnCuInS/ZnSe/ZnS Quantum Dot-Based Downconversion Light-Emitting Diodes and Their Thermal Effect

    Directory of Open Access Journals (Sweden)

    Wenyan Liu

    2015-01-01

    Full Text Available The quantum dot-based light-emitting diodes (QD-LEDs were fabricated using blue GaN chips and red-, yellow-, and green-emitting ZnCuInS/ZnSe/ZnS QDs. The power efficiencies were measured as 14.0 lm/W for red, 47.1 lm/W for yellow, and 62.4 lm/W for green LEDs at 2.6 V. The temperature effect of ZnCuInS/ZnSe/ZnS QDs on these LEDs was investigated using CIE chromaticity coordinates, spectral wavelength, full width at half maximum (FWHM, and power efficiency (PE. The thermal quenching induced by the increased surface temperature of the device was confirmed to be one of the important factors to decrease power efficiencies while the CIE chromaticity coordinates changed little due to the low emission temperature coefficients of 0.022, 0.050, and 0.068 nm/°C for red-, yellow-, and green-emitting ZnCuInS/ZnSe/ZnS QDs. These indicate that ZnCuInS/ZnSe/ZnS QDs are more suitable for downconversion LEDs compared to CdSe QDs.

  14. Dielectric behaviour of Zn substituted Cu nano-ferrites

    Energy Technology Data Exchange (ETDEWEB)

    Parashar, Jyoti, E-mail: phyjyoti.2@gmail.com [Department of Physics, University of Rajasthan, Jaipur 302055 (India); Saxena, V.K.; Jyoti; Bhatnagar, Deepak [Department of Physics, University of Rajasthan, Jaipur 302055 (India); Sharma, K.B. [Department of Physics, S.S. Jain Subodh P.G. College, Jaipur 302004 (India)

    2015-11-15

    Herein, the dielectric properties such as permittivity (real part ε′ and imaginary part ε′′) and dielectric loss tangent (tan δ) are reported for Zn substituted Cu ferrites (Cu{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4}; 0≤x≤1) composite using the sol–gel auto-combustion method. The variations of real and imaginary part of dielectric constant, tan δ and AC conductivity (σ{sub ac}) are studied at room temperature in the frequency range of 100 Hz–120 MHz. The real part of dielectric constant decrease with increasing frequency and the imaginary part (ε′′) varies with frequency showing the characteristic peak for each sample. The relation of tan δ with frequency shows relaxation spectra. Further, the σ{sub ac} tended to increase with increase in frequency. The variation in dielectric constant may be explained on the basis of space charge polarization, according to Maxwell and Wagner two-layer model. The dielectric constant and tan δ as a function of temperature are also studied with different temperatures ranging from 323 K to 583 K. - Highlights: • Zn substituted Cu nano-ferrite samples bearing formula Cu{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4}(0≤x≤1) are synthesized by the sol–gel auto combustion method. • The variation of real and imaginary parts of dielectric constant, dielectric loss tangent (tan δ) and AC conductivity with frequency are reported in the frequency range from 100 Hz to 120 MHz at room temperature. • The real part of dielectric constant (ε′) decreases with increasing frequency where as the AC conductivity (σ{sub ac}) increases with increase in frequency. The relation of tan δ with frequency shows relaxation spectra. • The variation in dielectric constant may be explained on the basis of space charge polarization, according to Maxwell and Wagner two-layer model. • Dielectric constant as a function of temperature is studied at different temperatures ranging from 323 K to 583 K.

  15. The Effects of Sputtering Target Preparation and Deposition Temperature on ZnTe:Cu Film Properties

    Energy Technology Data Exchange (ETDEWEB)

    Faulkner, Brooke R.; Ohno, T. R.; Burst, James M.; Duenow, Joel N.; Perkins, Craig L.; To, Bobby; Gessert, Timothy A.

    2015-06-14

    A back contact containing a sputtered ZnTe:Cu interface layer can produce high-performing thin-film CdS/CdTe photovoltaic devices. We have found that varying the ZnTe:Cu sputtering target fabrication processes and deposition temperature can affect material properties of the ZnTe:Cu films and the resulting device performance. Two different target 'recipes' with various copper contents were used to study changes in the compositional, structural, optical, and electrical properties of ZnTe:Cu films. Substrate temperature during deposition was also varied to investigate the temperature dependence of the films. It was found that the target recipe, Cu concentration in the target, and deposition temperature affect the composition of the ZnTe:Cu films, which impacts their structural, optical, and electrical properties.

  16. Facile synthesis and photocatalytic activity of bi-phase dispersible Cu-ZnO hybrid nanoparticles.

    Science.gov (United States)

    Liu, Xiao; Liu, HongLing; Zhang, WenXing; Li, XueMei; Fang, Ning; Wang, XianHong; Wu, JunHua

    2015-01-01

    Bi-phase dispersible Cu-ZnO hybrid nanoparticles were synthesized by one-pot non-aqueous nanoemulsion with the use of poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEO-PPO-PEO) as the surfactant. The transmission electron microscopy (TEM) and X-ray diffraction (XRD) show high crystallinity of the Cu-ZnO hybrid nanoparticles and an average particle size of ~19.4 nm. The ultraviolet-visible light absorbance spectrometry (UV-vis) and photoluminescence spectrophotometry (PL) demonstrate well dispersibility and excellent optical performance of Cu-ZnO hybrid nanoparticles both in organic and aqueous solvent. The X-ray photoelectron spectroscopy (XPS) confirms Cu(1+) and Cu(2+) in ZnO. The observation using Sudan red (III) as probe molecule reveals that the Cu-ZnO hybrid nanoparticles possess enhanced photocatalytic activity and stability which are promising for potential applications in photocatalysis.

  17. Zn—Cu Interaction Affecting Zn Adsorption and Plant Availability in a Metal—Contaminated Soil

    Institute of Scientific and Technical Information of China (English)

    D.L.Rimmer; LuoYongming

    1996-01-01

    In a previous greenhouse experiment,we showed that there was an interaction between cu and Zn,which affected growth and metal uptake by young barley plants grown on soil to which Cd,Cu,Pb,and Zn had been added.We suggested that the underlying mechanism was the control of the amount of plant-available Zn by competitive adsorption between Cu and Zn,In order to test this hypothesis,the adsorption of Zn alone,and in the presence of added Cd,Cu and Pb,has been measured using the same soil.Following adsorption,the extractability of the Zn in CaCl2 solution was measured .The adsorption isotherms showed that of the added metals only Cu had a large effect on Zn adsorption.The effect of Cu was to reduce Zn adsoption and to increase the amount of CaCl2-extractable(i.e.plant-available) Zn,in agreement with the conclusions from the greenhouse experiment.The magnitude of the effect of Cu on plant-avalilable Zn was similar in both experiments.

  18. Microstructure Properties of Rapidly Solidified Al-Zn-Mg-Cu Alloys

    Directory of Open Access Journals (Sweden)

    Emad M. Ahmed

    2014-01-01

    Full Text Available The Rietveld X-ray diffraction analysis was applied to analyze the weight fraction of precipitation phases and microstructure characterizations of rapidly solidified Al-8Zn-4Mg-xCu, x = 1, 4, 8, and 10 alloys (in wt.%, prepared by melt spun technique. A good agreement between observed and calculated diffraction pattern was obtained and the conventional Rietveld factors (Rp, Rwp, and GOF converged to satisfactory values. Solid solubilities of Zn, Mg, and Cu in α-Al were extended to high values. Besides, metastable Al0.71Zn0.29, intermetallic Al2CuMg, Al2Cu, and CuMgZn phases have been observed for x = 4, 8, and 10 Cu alloys. The crystal structure and microstructure characterizations exhibit strong Cu content dependence.

  19. Relationship between BMD and Zn, Cu, Ca Levels in the Hair and Meal in Elderly People

    Institute of Scientific and Technical Information of China (English)

    LI Wanli; TIAN Yuhui; SONG Xiaofei; ZHANG Min; SHEN Guanxin

    2005-01-01

    The relationship between bone mineral density (BMD) and Zn, Cu, Ca levels in the meal and hair of urban and rural elderly people were studied. 470 subjects above 60 years old (urban 205 and rural 265), 178 males with an average age of 65.70±3.48 and 292 females with an average age of 65.90±4.02, were inquired. The BMD and Zn, Cu, Ca levels in the meal and hair were measured. The detected BMD in urban and rural female old people was significantly lower than that of the males; The contents of Ca and Zn in the meal of the urban females were significantly lower than those of the urban males; The Ca, Zn in the meal and Zn in the hair of the rural females were significantly lower than those of rural males (P< 0.05 or 0.01). The BMD, Ca intakes, Ca and Zn in the hair of the rural old people were significantly lower than those of the urban old people (P<0.05 or 0.01). There was a correlation between BMD with the Ca, Zn of the hair and dietary Ca,Zn, Cu or between dietary Zn with Ca, Zn in the hair and Ca, Cu intakes. The Zn, Cu and Ca levels in the meal nutrients were correlated with BMD to some degrees. Lack of Ca and Zn in the meal can cause the reduction of BMD.

  20. Thermal behavior of MOCVD-grown Cu-clusters on ZnO(1010).

    Science.gov (United States)

    Kroll, Martin; Löber, Thomas; Schott, Vadim; Wöll, Christof; Köhler, Ulrich

    2012-02-01

    Scanning tunnelling microscopy (STM) and X-ray photoelectron spectroscopy (XPS, AES) were used to study MOCVD of Cu-clusters on the mixed terminated ZnO(1010) surface in comparison to MBE Cu-deposition. Both deposition methods result in the same Cu cluster morphology. After annealing to 670 K the amount of Cu visible above the oxide surface is found to decrease substantially, indicating a substantial diffusion of Cu atoms inside the ZnO-bulk. The spectroscopic data do not show any evidence for changes in the Cu oxidation state during thermal treatment up to 770 K.

  1. Radiative recombination in Cu2ZnSnSe4 thin films with Cu deficiency and Zn excess

    Science.gov (United States)

    Yakushev, M. V.; Márquez-Prieto, J.; Forbes, I.; Edwards, P. R.; Zhivulko, V. D.; Mudryi, A. V.; Krustok, J.; Martin, R. W.

    2015-12-01

    Thin films of Cu2ZnSnSe4 (CZTSe) with copper deficiency and zinc excess were fabricated at Northumbria University by the selenisation of metallic precursors deposited on Mo/glass and bare glass substrates. Absorption and photoluminescence (PL) measurements were used to examine the film on glass whereas films on Mo/glass were used to produce a solar cell with efficiency of 8.1%. Detailed temperature and excitation intensity analysis of PL spectra allows identification of the main recombination mechanisms as band-to-tail and band-to-band transitions. The latter transition was observed in the spectra from 6 to 300 K.

  2. Structural, chemical and optical evaluation of Cu-doped ZnO nanoparticles synthesized by an aqueous solution method

    Energy Technology Data Exchange (ETDEWEB)

    Iribarren, A., E-mail: augusto@imre.oc.uh.cu [Instituto de Ciencia y Tecnología de Materiales (IMRE), Universidad de La Habana, Zapata y G, Vedado, Plaza, La Habana 10400 (Cuba); Hernández-Rodríguez, E. [Instituto de Ciencia y Tecnología de Materiales (IMRE), Universidad de La Habana, Zapata y G, Vedado, Plaza, La Habana 10400 (Cuba); Maqueira, L. [Instituto de Ciencia y Tecnología de Materiales (IMRE), Universidad de La Habana, Zapata y G, Vedado, Plaza, La Habana 10400 (Cuba); Facultad de Química, Universidad de La Habana, Zapata y G, Vedado, Plaza, La Habana 10400 (Cuba)

    2014-12-15

    Highlights: • Cu-doped ZnO nanoparticles obtained by chemical synthesis. • Substitutional or interstitial Cu into ZnO lead specific structural, chemical, and optical changes. • Incorporation efficiency of Cu atoms in ZnO as a function of the Cu concentration in the precursor dissolution. - Abstract: In this work a study of ZnO and Cu-doped ZnO nanoparticles obtained by chemical synthesis in aqueous media was carried out. Structural analysis gave the dominant presence of wurtzite ZnO phase forming a solid solution Zn{sub 1−x}Cu{sub x}O. For high Cu doping CuO phase is also present. For low Cu concentration the lattice shrinks due to Cu atoms substitute Zn atoms. For high Cu concentration the lattice enlarges due to predominance of interstitial Cu. From elemental analysis we determined and analyzed the incorporation efficiency of Cu atoms in Zn{sub 1−x}Cu{sub x}O as a function of the Cu concentration in the precursor dissolution. Combining structural and chemical results we described the Cu/Zn precursor concentrations r{sub w} in which the solid solution of Cu in ZnO is predominant. In the region located at r{sub w} ≈ 0.2–0.3 it is no longer valid. For Cu/Zn precursor concentration r{sub w} > 0.3 interstitial Cu dominates, and some amount of copper oxide appears. As the Cu concentration increases, the effective size of nanoparticles decreases. Photoluminescence (PL) measurements of the Cu-doped ZnO nanoparticles were carried out and analyzed.

  3. Polarized Raman spectroscopy of Cu-poor and Zn-rich single-crystal Cu2ZnSnSe4

    Science.gov (United States)

    Nam, Dahyun; Kim, Jungcheol; Lee, Jae-Ung; Nagaoka, Akira; Yoshino, Kenji; Cha, Wonsuk; Kim, Hyunjung; Hwang, In Chul; Yoon, Kyung Byung; Cheong, Hyeonsik

    2014-10-01

    Cu2ZnSnSe4 (CZTSe) is a p-type semiconductor which has been developed as an absorber layer of polycrystalline thin film solar cells. Generally, Cu-poor and Zn-rich compositions tend to give the highest solar conversion efficiencies. Raman spectroscopy has been used to detect secondary phases such as ZnSe and Cu2SnSe3 in CZTSe thin films. However, the fundamental phonon modes in single-crystal CZTSe with a composition matching that of high-efficiency thin film solar cells have not yet been fully understood. We performed polarized Raman measurements on Cu-poor and Zn-rich single-crystal CZTSe and identified 12 peaks, including two low-frequency peaks. By comparing the polarization dependence of the Raman peaks with a group theoretical analysis, we concluded that the crystal structure of CZTSe single-crystal is kesterite and made appropriate peak assignments.

  4. Absolute densities of Cu, Zn, Sn, and S atoms in magnetron sputtering plasmas employing a Cu2ZnSnS4 target

    Science.gov (United States)

    Nafarizal, Nayan; Sasaki, Koichi

    2016-07-01

    Absolute densities of Cu, Zn, Sn, and S atoms in magnetron sputtering plasmas were measured by ultraviolet absorption spectroscopy and vacuum ultraviolet absorption spectroscopy. A stoichiometric Cu2ZnSnS4 (CZTS) target was used in this work. It was found that, at various Ar pressures, the S density ranged between (2-8) × 1010 cm-3, the Cu and Sn densities ranged between (0.6-3) × 1010 cm-3, and the Zn density ranged between (2-3) × 109 cm-3. The effective depositing flux, which was evaluated from the absolute densities and the sticking probabilities, was comparable with that evaluated from the deposition rate of the CZTS film. However, the composition ratio of Cu, Zn, Sn, and S in the gas phase deviated from the ideal stoichiometry of CZTS. We discussed the possible mechanisms for the difference among the element compositions of the target, the deposited film, and the gas-phase densities.

  5. Investigations on Cu2+-substituted Ni-Zn ferrite nanoparticles

    Science.gov (United States)

    Amarjeet; Kumar, Vinod

    2016-11-01

    CuxNi(1-x)/2Zn(1-x)/2Fe2O4 (x = 0.1, 0.3 and 0.5) nanoparticles were prepared by chemical co-precipitation method. The developed nanoparticles were characterized for structural properties by powder X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) techniques. Peak position in the X-ray diffraction pattern confirmed the single spinel phase of the developed particles. Infrared (IR) spectroscopy in mid-IR range showed the presence of characteristic absorption bands corresponding to octahedral and tetrahedral bonds in the spinel structure of prepared samples. Thermo-gravimetric analysis (TGA) measurements showed a considerable weight loss in the developed samples above 700∘C. Frequency dependence of the electrical properties of the developed material pellets was studied in the frequency range of 1 kHz-5 MHz. Temperature dependence of the dielectric constant of Cu0.1Ni0.45Zn0.45Fe2O4 was studied at different temperatures, i.e. at 425, 450 and 475 K, in the frequency range of 1 kHz-5 MHz. It was found that the electrical conductivity decreases with increasing Cu2+ ion content while it increases with the increase in temperature.

  6. Oxidación de Fenol con Catalizadores de CuO/Al2O3, CuO/ZnAl2O4 y CuO-ZnO-AlxOy Oxidation of Phenol with CuO/Al2O3, CuO/ZnAl2O4 and CuO-ZnO-AlxOy Catalysts

    Directory of Open Access Journals (Sweden)

    Isaías Hernández

    2006-01-01

    Full Text Available Fenol en agua residual industrial fue oxidado catalíticamente con O2 en un reactor por lotes. Para este fin, se evaluaron tres series de catalizadores preparados por impregnación de Cu(NO2 en Al2O3 y en ZnAl2O4 y por precipitación de nitratos de Cu, Zn y Al. Se caracterizaron por difracción de rayos-X, absorción atómica, microscopia electrónica, adsorción de N2 y termorreducción programada. Se observó CuO sobre las superficies de todos los catalizadores. Se encontró una fase amorfa solo en los catalizadores soportados en Al2O3 con alta área y en los demás fue cristalina con bajas áreas. La mayor velocidad de reacción fue obtenida por el catalizador másico de 22% de Cu. La velocidad de reacción máxima para todos los catalizadores fue cercana a una concentración de 20% de Cu. Durante la reacción se produjeron compuestos orgánicos oxigenados que aumentaron la acidez del agua residual, la cual atacó la superficie de los catalizadores disolviendo una parte pequeña de Cu, Zn y Al.Fenol in industrial residual water was oxidized catalytically with O2 in a batch reactor. For this purpose, three series of catalysts were evaluated which were prepared by impregnation of Cu(NO2 on Al2O3, on ZnAl2O4 and by precipitation of nitrates of Cu, Zn and Al. They were characterized by x-ray diffraction, atomic absorption, electronic microscopy, adsorption of N2 and temperature programmed reduction. CuO very dispersed was observed on the surface of all the catalysts. It was found an amorphous phase in the Al2O3 supported catalysts with high surface area and in the other ones it was crystalline with low areas. The highest reaction rate was obtained for the massive catalyst with 22% of Cu. The maximum of reaction rate for all the catalysts was near to 20% of Cu. During the reaction it was produced oxygenated organic compounds which increased the acidity of the residual water, which attacked the surface of the catalysts dissolving a small amount of

  7. Pine bark as bio-adsorbent for Cd, Cu, Ni, Pb and Zn

    DEFF Research Database (Denmark)

    Cutillas-Barreiro, L.; Ansias-Manso, L.; Fernandez Calviño, David;

    2014-01-01

    % for Pb2+, 83-84% for Cu2+, 78-84% for Cd2+, 77-83% for Zn2+, and 70-75% for Ni2+, and it was faster for low concentrations, with Pb suffering the highest retention, followed by Cu, Cd, Ni and Zn. The fitting to the Freundlich and Langmuir models was satisfactory. Desorption increased in parallel...

  8. Formation of ferric flocks for the removal of Zn and Cu from dockyard wastewater

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Arevalo, Edurado; Stichnothe, Heinz

    2006-01-01

    Wastewater from wash down of boat hulls contains typically Cu, Zn and organometallic biocides, e.g. tributyltin (TBT). In some cases this wastewater is led directly into the marine system. In the present paper a cheap flocculation method (iron flocculants) for removal of Cu and Zn from...

  9. Activation of a Cu/ZnO catalyst for methanol synthesis

    DEFF Research Database (Denmark)

    Andreasen, Jens Wenzel; Rasmussen, F.B.; Helveg, S.;

    2006-01-01

    The structural changes during activation by temperature-programmed reduction of a Cu/ZnO catalyst for methanol synthesis have been studied by several in situ techniques. The catalyst is prepared by coprecipitation and contains 4.76 wt% Cu, which forms a substitutional solid solution with Zn...

  10. Selective recovery of Cu, Zn, and Ni from acid mine drainage.

    Science.gov (United States)

    Park, Sang-Min; Yoo, Jong-Chan; Ji, Sang-Woo; Yang, Jung-Seok; Baek, Kitae

    2013-12-01

    In Korea, the heavy metal pollution from about 1,000 abandoned mines has been a serious environmental issue. Especially, the surface waters, groundwaters, and soils around mines have been contaminated by heavy metals originating from acid mine drainage (AMD) and mine tailings. So far, AMD was considered as a waste stream to be treated to prevent environmental pollutions; however, the stream contains mainly Fe and Al and valuable metals such as Ni, Zn, and Cu. In this study, Visual MINTEQ simulation was carried out to investigate the speciation of heavy metals as functions of pH and neutralizing agents. Based on the simulation, selective pH values were determined to form hydroxide or carbonate precipitates of Cu, Zn, and Ni. Experiments based on the simulation results show that the recovery yield of Zn and Cu were 91 and 94 %, respectively, in a binary mixture of Cu and Zn, while 95 % of Cu and 94 % of Ni were recovered in a binary mixture of Cu and Ni. However, the recovery yield and purity of Zn and Ni were very low because of similar characteristics of Zn and Ni. Therefore, the mixture of Cu and Zn or Cu and Ni could be recovered by selective precipitation via pH adjustment; however, it is impossible to recover selectively Zn and Ni in the mixture of them.

  11. Synthesis CuO-ZnO nanocomposite and its application as an antibacterial agent

    Science.gov (United States)

    Widiarti, N.; Sae, J. K.; Wahyuni, S.

    2017-02-01

    The synthesis of CuO-ZnO composites and their application as anti-bacterial have been conducted. Nanocomposite CuO-ZnO was synthesized using sol-gel method. The nanocomposite products were characterized by XRD, DR-UV, SAA, FTIR, SEM-EDX. The results of the XRD analysis showed that the CuO-ZnO composite has a nanometer size with the average of 15.99 nanometer. The DR-UV analysis showed that the CuO-ZnO composite has a band-gap of 2.28 eV in the average. The analysis of SAA showed that the CuO-ZnO has a surface area of 23.20 m2/g in average. FTIR investigation revealed that the vibration of ZnO was observed at 432.05 cm-1 whereas CuO at 524.64 cm-1 and 594, 06 cm-1. The SEM-EDX analysis showed that the ZnO has a hexagonal structure whereas the CuO has a monoclinic structure. The CuO-ZnO nanocomposite has the ability as an antibacterial against S. aureus as gram-positive and E. coli as Gram-negative bacteria.

  12. Formation of ferric flocks for the removal of Zn and Cu from dockyard wastewater

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Arevalo, Edurado; Stichnothe, Heinz

    2006-01-01

    Wastewater from wash down of boat hulls contains typically Cu, Zn and organometallic biocides, e.g. tributyltin (TBT). In some cases this wastewater is led directly into the marine system. In the present paper a cheap flocculation method (iron flocculants) for removal of Cu and Zn from the wastew...

  13. First-principles investigation of Cu-doped ZnS with enhanced photocatalytic hydrogen production activity

    Science.gov (United States)

    Dong, Ming; Zhou, Peng; Jiang, Chuanjia; Cheng, Bei; Yu, Jiaguo

    2017-01-01

    The band structure and electronic properties of Cu-doped wurtzite ZnS were investigated by density functional theory calculations. According to the formation energies, the substitutional Cu and S vacancy defects are stable among the examined doping species. Particularly, the hybridization of substitutional Cu 3d and S 3p orbitals narrows the band gap of substitutional Cu-doped ZnS (CuZn-ZnS), while the high effective mass ratio of photogenerated holes and electrons (mh∗/me∗) in the CuZn-ZnS is beneficial for the separation and migration of the photogenerated charge carriers. Lab-synthesized CuZn-ZnS sample exhibited enhanced visible-light absorption and photocatalytic hydrogen production activity compared to pure ZnS.

  14. On the concentration and separation of the trace-elements fe, cu, zn, mn, pb, mo and co : Paper chromatography

    NARCIS (Netherlands)

    Erkelens, P.C. van

    1961-01-01

    Paper chromatographic separations are described by which the minor constituents of biological ashes are separated either into: (Pb) - Mn - Co - (Pb) - Cu - Fe, Mo, Zn; or into: Cu, Mn, Co - Pb - Fe - Mo - Zn.

  15. Reversible switching of ferromagnetism in ZnCuO nanorods by electric field

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Changwei, E-mail: Changweizou@hotmail.com; Wang, Hongjun; Liang, Feng; Shao, Lexi [Department of Physics and Development Center for New Materials Engineering and Technology in Universities of Guangdong, Lingnan Normal University, Zhanjiang 524048 (China)

    2015-04-06

    The reproducible switching of ferromagnetism in ZnCuO nanorods by applying a reversible electric field has been realized. High-resolution transmission electron microscopy images showed a hexagonal wurtzite structure with no detectable trace of secondary phase or precipitation of Cu impurity in the ZnCuO nanorods. The Cu concentrations in the ZnCuO nanorods were tested by energy dispersive spectroscopy and x-ray photoelectron spectroscopy and found to be about 2.7 at. %. The switching mechanism is confirmed in terms of the formation and rupture of conductive filaments, with oxygen vacancies (V{sub O}) localized mainly on surface of the ZnCuO nanorods. Subsequently, the variation of V{sub O} concentration during the resistive switching process modulates the ferromagnetism of the ZnCuO nanorods. The saturation magnetization at low resistance state is apparently 6.4 times larger than that at high resistance state for an Au/ZnCuO/ITO structure. An indirect double-exchange model has been used to explain the ferromagnetism in ZnCuO nanorods.

  16. Continuous determination of Cu, Al, Zn in Ag- Cu- Al- Zn quarternary alloy by titration%滴定法连续测定银铜铝锌四元合金中Cu,Al,Zn

    Institute of Scientific and Technical Information of China (English)

    麦丽碧

    2004-01-01

    采用连续滴定的方法同时测定Cu,Al,Zn.加入一定量的EDTA标准溶液,使Cu2+,Al3+,Zn2+全部与EDTA络合,用Zn2+盐滴定过量EDTA,然后加氟盐置换出EDTA-Al中的EDTA,用硫脲抗坏血酸和邻菲啰啉置换出EDTA-Cu中的EDTA,并分别用Zn2+盐滴定,从总量中减去Al量和Cu量即得Zn量.滴定Cu,Al,Zn回收率均在98%以上,本法分析快速准确.

  17. Quantifying the promotion of Cu catalysts by ZnO for methanol synthesis

    DEFF Research Database (Denmark)

    Kuld, Sebastian; Thorhauge, Max; Falsig, Hanne

    2016-01-01

    Promoter elements enhance the activity and selectivity of heterogeneous catalysts. Here, we show how methanol synthesis from synthesis gas over copper (Cu) nanoparticles is boosted by zinc oxide (ZnO) nanoparticles. By combining surface area titration, electron microscopy, activity measurement......, density functional theory calculations, and modeling, we show that the promotion is related to Zn atoms migrating in the Cu surface. The Zn coverage is quantitatively described as a function of the methanol synthesis conditions and of the size-dependent thermodynamic activities of the Cu and Zn...

  18. Molecular distortion and charge transfer effects in ZnPc/Cu(111)

    KAUST Repository

    Amin, B.

    2013-04-23

    The adsorption geometry and electronic properties of a zinc-phthalocyanine molecule on a Cu(111) substrate are studied by density functional theory. In agreement with experiment, we find remarkable distortions of the molecule, mainly as the central Zn atom tends towards the substrate to minimize the Zn-Cu distance. As a consequence, the Zn-N chemical bonding and energy levels of the molecule are significantly modified. However, charge transfer induces metallic states on the molecule and therefore is more important for the ZnPc/Cu(111) system than the structural distortions.

  19. Cooperative cytotoxic activity of Zn and Cu in bovine serum albumin-conjugated ZnS/CuS nano-composites in PC12 cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hua-Jie, E-mail: wanghuajie972001@163.com; Yu, Xue-Hong; Wang, Cai-Feng; Cao, Ying, E-mail: caoying1130@sina.com [Henan Normal University, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, College of Chemistry and Chemical Engineering (China)

    2013-11-15

    Series of self-assembled and mono-dispersed bovine serum albumin (BSA)-conjugated ZnS/CuS nano-composites with different Zn/Cu ratios had been successfully synthesized by a combination method of the biomimetic synthesis and ion-exchange strategy under the gentle conditions. High-resolution transmission electron microscopy observation, Fourier transform infrared spectra and zeta potential analysis demonstrated that BSA-conjugated ZnS/CuS nano-composites with well dispersity had the hierarchical structure and BSA was a key factor to control the morphology and surface electro-negativity of final products. The real-time monitoring by atomic absorption spectroscopy and powder X-ray diffraction revealed that the Zn/Cu ratio of nano-composites could be controlled by adjusting the ion-exchange time. In addition, the metabolic and morphological assays indicated that the metabolic proliferation and spread of rat pheochromocytoma (PC12) cells could be inhibited by nano-composites, with the high anti-cancer activity at a low concentration (4 ppm). What were more important, Zn and Cu in nano-composites exhibited a positive cooperativity at inhibiting cancer cell functions. The microscope observation and biochemical marker analysis clearly revealed that the nano-composites-included lipid peroxidation and disintegration of membrane led to the death of PC12 cells. Summarily, the present study substantiated the potential of BSA-conjugated ZnS/CuS nano-composites as anti-cancer drug.

  20. Photocatalytic Characterization of Fe- and Cu-Doped ZnO Nanorods Synthesized by Cohydrolysis

    Directory of Open Access Journals (Sweden)

    Young Rang Uhm

    2013-01-01

    Full Text Available Fe- and Cu-doped ZnO nanorods have been synthesized by a novel process employing a hydrolysis of metal powders. Zn, Fe, and Cu nanopowders were used as starting materials and incorporated into distilled water. The solution was refluxed at 60°C for 24 h to obtain the precipitates from the hydrolysis of Zn and dopants (Cu and Fe. The TEM results for ZnO with and without metal doping showed that the produced powders had a rod-like shape. The rod shape was attributable to the zinc oxide from the hydrolysis of Zn. With an increasing doping content, the UV-vis spectra were shifted to a long wavelength and this result indicates that the band gap was changed by the metal doping. The values of phenol degrading Fe- and Cu-doped ZnO by a solar simulator were measured to be 60 and 75%, respectively.

  1. Cu2ZnSnSe4 thin-film solar cells fabricated using Cu2SnSe3 and ZnSe bilayers

    Science.gov (United States)

    Kim, Kang Min; Liao, Kuang Hsiang; Tampo, Hitoshi; Shibata, Hajime; Niki, Shigeru

    2015-04-01

    Evaporated Cu2SnSe3 (CTSe) and ZnSe bilayers are used as precursors for the fabrication of Cu2ZnSnSe4 (CZTSe) thin films. Large grains (i.e., >1 µm) in CZTSe were obtained at a relatively low annealing temperature of 500 °C. The stacking order of precursors strongly affected the chemical composition of CZTSe thin films even under identical growth conditions. Zn loss in CTSe/ZnSe/Mo precursors occurred during CTSe deposition, whereas ZnSe/CTSe/Mo precursors showed improved stability in composition. The CZTSe solar cells fabricated using ZnSe/CTSe bilayer precursors with annealing showed a conversion efficiency of over 7%.

  2. As-cast microstructure of Al-Zn-Mg and Al-Zn-Mg-Cu alloys added erbium

    Institute of Scientific and Technical Information of China (English)

    MAO Jian-wei; JIN Tou-nan; XU Guo-fu; NIE Zuo-ren

    2005-01-01

    The effects of different contents of rare earth element, and erbium, on the as-cast microstructures of Al-6Zn-2Mg and Al-6Zn-2Mg-1.8Cu alloys were studied by optical microscopy, scanning electron microscopy, X-ray diffractometry, transmission electron microscopy and EDS analysis. The results show that the netlike structure of as-cast alloys can be remarkably refined, and the distance of dendritic structure decreases, with Er addition. However, the improvement results on Al-Zn-Mg-Cu are not better than that of Al-Zn-Mg. Er and Al can interact to form Al3Er phase, which is coherent with α(Al) matrix, with trace Er addition to the Al-Zn-Mg alloy. The refinement effect of Al-Zn-Mg alloys is familiar with the formation and precipitation of coherent Al3Er phases. The ternary compound AlCuEr, similar with AlCuSc phase, will form when Er is added to Al-Zn-Mg-Cu alloy, which suppresses the formation of Al3Er phase and doesn't solve in the following heat treatment.

  3. Cation/Anion Substitution in Cu2ZnSnS4 for Improved Photovoltaic Performance

    OpenAIRE

    Balakrishna Ananthoju; Jeotikanta Mohapatra; Jangid, Manoj K.; Bahadur, D.; Medhekar, N. V.; ASLAM, M.

    2016-01-01

    Cations and anions are replaced with Fe, Mn, and Se in CZTS in order to control the formations of the secondary phase, the band gap, and the micro structure of Cu2ZnSnS4. We demonstrate a simplified synthesis strategy for a range of quaternary chalcogenide nanoparticles such as Cu2ZnSnS4 (CZTS), Cu2FeSnS4 (CFTS), Cu2MnSnS4 (CMTS), Cu2ZnSnSe4 (CZTSe), and Cu2ZnSn(S0.5Se0.5)4 (CZTSSe) by thermolysis of metal chloride precursors using long chain amine molecules. It is observed that the crystal s...

  4. Research on Cu2ZnSnTe4 crystals and heterojunctions based on such crystals

    Directory of Open Access Journals (Sweden)

    Kovaliuk T. T.

    2015-12-01

    Full Text Available The paper reports on the results of the studies of magnetic, kinetic and optical properties of Cu2ZnSnTe4 crystals. The Cu2ZnSnTe4 crystals showed diamagnetic properties (the magnetic susceptibility almost independent of the magnetic field and temperature. The Cu2ZnSnTe4 crystals possessed p-type of conductivity and the Hall coefficient was independent on temperature. The temperature dependence of the electrical conductivity of the Cu2ZnSnTe4 crystal shows metallic character, i. e. decreases with the increase of temperature, that is caused by the lower charge carrier mobility at higher temperature. Thermoelectric power of the samples ispositive that also indicates on the prevalence of p-type conductivity. Heterojunctions n-TiN/p-Cu2ZnSnTe4, n-TiO2/p-Cu2ZnSnTe4 and n-MoO/p-Cu2ZnSnTe4 were fabricated by the reactive magnetron sputtering of TiN, TiO2 and MoOx thin films, respectively, onto the substrates made of the Cu2ZnSnTe4 crystals. The dominating current transport mechanisms in the n-TiN/p-Cu2ZnSnTe4 and n-TiO2/p-Cu2ZnSnTe4 heterojunctions were established to be the tunnel-recombination mechanism at forward bias and tunneling at reverse bias.

  5. Sputtered Ni-Zn under bump metallurgy (UBM) for Sn-Ag-Cu solders

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae Jin; Kim, Young Min [Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Kim, Young-Ho, E-mail: kimyh@hanyang.ac.kr [Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer Ni-Zn UBM can effectively suppress the growth of IMCs and the consumption of UBM. Black-Right-Pointing-Pointer The growth of (Ni, Cu){sub 3}Sn{sub 4} was retarded at the SAC305/Ni-Zn interface after aging. Black-Right-Pointing-Pointer Only a single (Cu, Ni){sub 6}Sn{sub 5} formed at the SAC107/Ni-Zn interface after aging. Black-Right-Pointing-Pointer Segregated Zn atoms on IMC layers retarded the interdiffusion of Cu, Ni, and Sn. Black-Right-Pointing-Pointer Sputtered Ni-Zn UBM is promising for Pb-free solder flip chip applications. - Abstract: We developed a new sputtered under bump metallurgy (UBM) based on Ni-20wt% Zn thin films for Pb-free solders. This study focuses on the interfacial reactions between two Pb-free solders (Sn3.0Ag0.5Cu and Sn1.0Ag0.7Cu) and a Ni-Zn alloy UBM. By adding Zn to Ni UBM, Zn is incorporated into intermetallic compounds (IMCs) to form a quaternary Cu-Ni-Zn-Sn phase at the solder/Ni-Zn interface after reflow and subsequent isothermal aging. The Ni-Zn UBM sufficiently reduces the interfacial reaction and IMCs formation rates as well as UBM consumption rates compared to a Ni UBM. In particular, the formation of (Ni, Cu){sub 3}Sn{sub 4} IMC was significantly retarded by adding Zn into UBM.

  6. Evolution of intermetallic phases of Al-Zn-Mg-Cu alloy during heat treatment

    Institute of Scientific and Technical Information of China (English)

    FAN Xi-gang; JIANG Da-ming; MENG Qing-chang; LI Nian-kui; SUN Zhao-xia

    2006-01-01

    Al-Zn-Mg-Cu alloy is a favorable choice for aerospace applications requiring good combination of strength and toughness,which is greatly influenced by the coarse intermetallic particles. The evolution of intermetallic particles in an Al-Zn-Mg-Cu alloy during heat treatment was studied by field emission gun scanning electron microscopy (FEG-SEM) and X-ray diffractometry(XRD).The results show that there are lamellar eutectic structure (α(Al)+Mg(Zn,Al,Cu)2) and Al7Cu2Fe particles in the solidified structure.The Al7Cu2Fe particles are embedded in the eutectic structure. The content of eutectic structure decreases with the increase of holding time and disappears after 24 h. The size and morphology of Al7Cu2Fe particles exhibit no change during the heat treatment. It is found that the Al2CuMg phase is formed during the treatment at 460 ℃. A transformation process from the primary eutectic phase Mg(Zn,Al,Cu)2 to Al2CuMg is observed, and the transformation mechanism and kinetics are analyzed. The Al2CuMg constituents form in the primary Mg(Zn,Al,Cu)2 phase, and grow along the eutectic microstructure.

  7. Effect of Cu content and temperature on the properties of Cu2ZnSnSe4 solar cells

    Science.gov (United States)

    Sahayaraj, Sylvester; Brammertz, Guy; Buffière, Marie; Meuris, Marc; Vleugels, Jef; Poortmans, Jef

    2016-09-01

    The complexity involved in obtaining pure Kesterite Cu2ZnSnSe4 (CZTSe) thin film primarily arises due to its narrow region of stability, leading to the presence of unavoidable binary selenides of the constituent metals. This study offers an insight on the formation of Cu selenides when the amount of Cu is varied in the precursor from Cu poor to Cu rich. The amount of Cu selenides was found to decrease when the composition of CZTSe absorber approached Cu rich conditions but functional devices were not obtained. Detailed characterizations also showed that the Cu and Sn binary phases were present at the backside interface of CZTSe solar cells. However with an increase in the selenization temperature it was found that the amount of Cu selenides and other secondary phases could be drastically minimized or even eliminated leading to high efficiency devices.

  8. Effect of Cu content and temperature on the properties of Cu2ZnSnSe4 solar cells

    Directory of Open Access Journals (Sweden)

    Sahayaraj Sylvester

    2016-01-01

    Full Text Available The complexity involved in obtaining pure Kesterite Cu2ZnSnSe4 (CZTSe thin film primarily arises due to its narrow region of stability, leading to the presence of unavoidable binary selenides of the constituent metals. This study offers an insight on the formation of Cu selenides when the amount of Cu is varied in the precursor from Cu poor to Cu rich. The amount of Cu selenides was found to decrease when the composition of CZTSe absorber approached Cu rich conditions but functional devices were not obtained. Detailed characterizations also showed that the Cu and Sn binary phases were present at the backside interface of CZTSe solar cells. However with an increase in the selenization temperature it was found that the amount of Cu selenides and other secondary phases could be drastically minimized or even eliminated leading to high efficiency devices.

  9. Highly efficient photocatalytic degradation of organic dyes by Cu doped ZnO nanostructures.

    Science.gov (United States)

    Kuriakose, Sini; Satpati, Biswarup; Mohapatra, Satyabrata

    2015-10-14

    Copper doped ZnO nanostructures have been synthesized by a facile wet chemical method. Structural properties of as-synthesized nanomaterials have been studied by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) with energy dispersive X-ray spectroscopy, while UV-visible absorption spectroscopy and Raman spectroscopy have been used to study their optical properties. Sunlight driven photocatalytic degradation of methylene blue (MB) and methyl orange (MO) dyes in water was used to evaluate the photocatalytic activities of Cu doped ZnO nanostructures using UV-visible absorption spectroscopy. The results showed that there is an optimum Cu doping level which leads to the highly enhanced photocatalytic activity of Cu doped ZnO nanostructures, as compared to pure ZnO nanostructures. A mechanism for the enhanced photocatalytic activity of Cu-ZnO nanostructures is tentatively proposed. The enhanced photocatalytic activity of Cu-ZnO nanostructures is attributed to the combined effects of improved separation of photogenerated charge carriers due to optimal Cu doping in ZnO nanostructures and the formation of ZnO-CuO nanoheterojunctions.

  10. Crevice Corrosion of the Shape Memory Alloy Cu-Zn-Al%Cu-Zn-Al形状记忆合金的缝隙腐蚀

    Institute of Scientific and Technical Information of China (English)

    郭海霞; 梁成浩

    2001-01-01

    The crevice corrosion of the benzotriazole(BTA) passive specimensof the shape memory alloy Cu-Zn-Al in Hank's artificial body fluid has been studied using electrochemical tests. The results show that the shape memory alloy Cu-Zn-Al exhibits better property than the annealed alloy Cu-Zn-Al. T he reason is that the martensite single phase in the alloy Cu-Zn-Al improves electrochemical property and inhibits active solution. The occurring of crevice corrosion is attributed to the metal ions concentration cell. BTA passivation improves the crevice corrosion resistance of the alloy.%采用电化学方法研究了Cu-Zn-Al形状记忆合金及其BTA钝化处理试样在Hank's人工体液中的缝隙腐蚀行为。结果表明:在人工体液中,Cu-Zn-Al形状记忆合金的耐缝隙腐蚀性能优于未进行热处理的Cu-Zn-Al合金,其作用机理是单相马氏体组织改善了合金的电化学行为,抑制了活性溶解。缝隙腐蚀的发生是由于形成了金属离子浓差电池。经BTA钝化后,Cu-Zn-Al形状记忆合金的耐缝隙腐蚀性能得到改善。

  11. First-principle Calculations of Mechanical Properties of Al2Cu, Al2CuMg and MgZn2 Intermetallics in High Strength Aluminum Alloys

    Directory of Open Access Journals (Sweden)

    LIAO Fei

    2016-12-01

    Full Text Available Structural stabilities, mechanical properties and electronic structures of Al2Cu, Al2CuMg and MgZn2 intermetallics in Al-Zn-Mg-Cu aluminum alloys were determined from the first-principle calculations by VASP based on the density functional theory. The results show that the cohesive energy (Ecoh decreases in the order MgZn2 > Al2CuMg > Al2Cu, whereas the formation enthalpy (ΔH decreases in the order MgZn2 > Al2Cu > Al2CuMg. Al2Cu can act as a strengthening phase for its ductile and high Young's modulus. The Al2CuMg phase exhibits elastic anisotropy and may act as a crack initiation point. MgZn2 has good plasticity and low melting point, which is the main strengthening phase in the Al-Zn-Mg-Cu aluminum alloys. Metallic bonding mode coexists with a fractional ionic interaction in Al2Cu, Al2CuMg and MgZn2, and that improves the structural stability. In order to improve the alloys' performance further, the generation of MgZn2 phase should be promoted by increasing Zn content while Mg and Cu contents are decreased properly.

  12. Highly efficient visible light photocatalysis of novel CuS/ZnO heterostructure nanowire arrays

    Science.gov (United States)

    Lee, Mikyung; Yong, Kijung

    2012-05-01

    Here, a facile approach for the fabrication of CuS nanoparticle (NP)/ZnO nanowire (NW) heterostructures on a mesh substrate through a simple two-step solution method is demonstrated. Successive ionic layer adsorption and reaction (SILAR) was employed to uniformly deposit CuS NPs on the hydrothermally grown ZnO NW array. The synthesized CuS/ZnO heterostructure NWs exhibited superior photocatalytic activity under visible light compared to bare ZnO NWs. This strong photocatalytic activity under visible light is due to the interfacial charge transfer (IFCT) from the valence band of the ZnO NW to the CuS NP, which reduces CuS to Cu2S. After repeated cycles of photodecolorization of Acid Orange 7 (AO7), the photocatalytic behavior of CuS/ZnO heterostructure NWs exhibited no significant loss of activity. Furthermore, our CuS/ZnO NWs/mesh photocatalyst floats in solution via partial superhydrophobic modification of the NWs.

  13. Cu-doped ZnO nanoparticles: Synthesis, structural and electrical properties

    Science.gov (United States)

    Singhal, Sonal; Kaur, Japinder; Namgyal, Tsering; Sharma, Rimi

    2012-04-01

    Pure and Cu doped ZnO nanopowders (5, 10, 15, 20, 25 and 30 at% Cu) have been synthesized using co-precipitation method. Transmission Electron Microscopic analysis has shown the morphology of ZnO nanopowders to be quasi-spherical. Powder X-ray Diffraction studies have revealed the systematic doping of Cu into the ZnO lattice up to 10% Cu, though the peaks corresponding to CuO in 10% Cu are negligibly very small. Beyond this level, there was segregation of a secondary phase corresponding to the formation of CuO. Fourier Transform Infrared spectra have shown a broad absorption band at ∼490 cm-1 for all the samples, which corresponds to the stretching vibration of Zn-O bond. DC electrical resistivity has been found to decrease with increasing Cu content. The activation energy has also been observed to decrease with copper doping i.e. from ∼0.67 eV for pure ZnO to ∼0.41 eV for 30 at% Cu doped ZnO.

  14. Cu-doped ZnO nanoparticles: Synthesis, structural and electrical properties

    Energy Technology Data Exchange (ETDEWEB)

    Singhal, Sonal, E-mail: sonal1174@gmail.com [Department of Chemistry, Panjab University, Chandigarh 160014 (India); Kaur, Japinder; Namgyal, Tsering; Sharma, Rimi [Department of Chemistry, Panjab University, Chandigarh 160014 (India)

    2012-04-15

    Pure and Cu doped ZnO nanopowders (5, 10, 15, 20, 25 and 30 at% Cu) have been synthesized using co-precipitation method. Transmission Electron Microscopic analysis has shown the morphology of ZnO nanopowders to be quasi-spherical. Powder X-ray Diffraction studies have revealed the systematic doping of Cu into the ZnO lattice up to 10% Cu, though the peaks corresponding to CuO in 10% Cu are negligibly very small. Beyond this level, there was segregation of a secondary phase corresponding to the formation of CuO. Fourier Transform Infrared spectra have shown a broad absorption band at {approx}490 cm{sup -1} for all the samples, which corresponds to the stretching vibration of Zn-O bond. DC electrical resistivity has been found to decrease with increasing Cu content. The activation energy has also been observed to decrease with copper doping i.e. from {approx}0.67 eV for pure ZnO to {approx}0.41 eV for 30 at% Cu doped ZnO.

  15. Calculation and measurement of helium generation and solid transmutations in Cu-Zn-Ni alloys

    Energy Technology Data Exchange (ETDEWEB)

    Greenwood, L.R.; Oliver, B.M.; Garner, F.A. [Pacific Northwest National Lab., Richland, WA (United States); Muroga, T. [National Inst. of Fusion Science, Nagoya (Japan)

    1998-03-01

    A method was recently proposed by Garner and Greenwood that would allow the separation of the effects of solid and gaseous transmutation for Cu-Zn-Ni alloys. Pure copper produces zinc and nickel during neutron irradiation. {sup 63}Cu transmutes to {sup 64}Ni and {sup 64}Zn, in about a 2-to-1 ratio, and {sup 65}Cu transmutes to {sup 66}Zn. The {sup 64}Zn further transmutes to {sup 65}Zn which has been shown to have a high thermal neutron (n,{alpha}) cross-section. Since a three-step reaction sequence is required for natural copper, the amount of helium produced is much smaller than would be produced for the two-step, well-known {sup 58}Ni (n,{gamma}) {sup 59}Ni (n,{alpha}) reaction sequence. The addition of natural Zn and Ni to copper leads to greatly increased helium production in neutron spectra with a significant thermal component. Using a suitable Cu-Zn-Ni alloy matrix and comparative irradiation of thermal neutron-shielded and unshielded specimens, it should be possible to distinguish the separate influences of the solid and gaseous transmutants. Whereas helium generation rates have been previously measured for natural nickel and copper, they have not been measured for natural Zn or Cu-Ni-Zn alloys. The (N,{alpha}) cross section for {sup 65}Zn was inferred from helium measurements made with natural copper. By comparing helium production in Cu and Cu-Zn alloys, this cross section can be determined more accurately. In the current study, both the solid and helium transmutants were measured for Cu, Cu-5Ni, Cu-3.5Zn and Cu-5Ni-2Zn, irradiated in each of two positions in the HFIR JP-23 test. Highly accurate helium measurements were performed on these materials by isotope dilution mass spectrometry using a facility that was recently moved from Rockwell International to PNNL. It is shown that both the helium and solid transmutants for Cu-zn-Ni alloys can be calculated with reasonable certainty, allowing the development of a transmutation experiment as proposed by

  16. Synthesis and characterization of (Cd,Zn)S buffer layer for Cu2ZnSnSe4 solar cells

    Science.gov (United States)

    Ben Messaoud, Khaled; Buffière, Marie; Brammertz, Guy; Lenaers, Nick; Boyen, Hans-Gerd; Sahayaraj, Sylvester; Meuris, Marc; Amlouk, Mosbah; Poortmans, Jef

    2017-07-01

    In order to improve the electrical performances of Cu2ZnSnSe4 (CZTSe) based solar cells, the standard CdS buffer layer was replaced by (Cd,Zn)S processed by chemical bath deposition. The morphology and composition of the (Cd,Zn)S thin films were studied as a function of [Zn]/([Zn]  +  [Cd]) ratio in the chemical bath (80, 85 and 90%). The CZTSe/(Cd,Zn)S solar cells with and without Cd partial electrolyte (Cd PE) treatment were compared to CZTSe/CdS reference devices using current-voltage and external quantum efficiency measurements. The (Cd,Zn)S thin films show a non-homogeneity of Zn distribution and phase formation, with a shift from Zn(O,OH) x to ZnS phase when increasing the deposition time and a decrease of the layers thicknesses when increasing the Zn concentration in chemical bath. A model for the growth of (Cd,Zn)S thin films is proposed. The resulting CZTSe/(Cd,Zn)S devices show an important reduction of the barrier at the hetero-interface, which is attributed to the lower density of O contamination in (Cd,Zn)S compared to CdS, inducing a lower density of deep p-type recombination centers. Despite the reduced compensation of the buffer layer, CZTSe/(Cd,Zn)S devices show a deterioration of the open circuit voltage and the fill factor with the increase of Zn content in (Cd,Zn)S. These electrical losses were avoided by Cd PE treatment prior to the deposition of (Cd,Zn)S.

  17. Enhanced bake-hardening response of an Al–Mg–Si–Cu alloy with Zn addition

    Energy Technology Data Exchange (ETDEWEB)

    Guo, M.X., E-mail: mingxingguo@skl.ustb.edu.cn [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Sha, G., E-mail: gang.sha@njust.edu.cn [School of Materials Science and Engineering, Nanjing University of Science and Technology, Jiangsu 210094 (China); Cao, L.Y. [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Liu, W.Q. [Key Laboratory for Microstructures, Shanghai University, Shanghai 200444 (China); Zhang, J.S.; Zhuang, L.Z. [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China)

    2015-07-15

    This study reports that Zn addition greatly enhances the bake-hardening response of an Al–Mg–Si–Cu alloy. The pre-aged alloy exhibits a high strength increment of 135 MPa after paint baking. Differential scanning calorimetry, atom probe tomography and high-resolution transmission electron microscopy reveal that Zn addition and pre-aging have significant effects on the solute nanostructure formation. Zn atoms partition into solute clusters/GP zones, and reduce the activation energy of β” precipitation in the alloy. - Highlights: • Zn addition can improve the bake-hardening response of an Al–Mg–Si–Cu alloy. • Zn addition can stabilize the solute clusters/GP zones from dissolution. • Zn addition can reduce the size of clusters formed in the pre-aging treatment. • Zn partitioned into solute clusters/GP zones and β” in the Zn-containing Al alloy.

  18. Non-isothermal precipitation behaviors of Al-Mg-Si-Cu alloys with different Zn contents

    Energy Technology Data Exchange (ETDEWEB)

    Guo, M.X., E-mail: mingxingguo@skl.ustb.edu.cn; Zhang, Y.; Zhang, X.K.; Zhang, J.S.; Zhuang, L.Z.

    2016-07-04

    The non-isothermal precipitation behaviors of Al–Mg–Si–Cu alloys with different Zn contents were investigated by differential scanning calorimetry (DSC) analysis, hardness measurement and high resolution transmission electron microscope characterization. The results show that Zn addition has a significant effect on the GP zone dissolution and precipitation of Al-Mg-Si-Cu alloys. And their activation energies change with the changes of Zn content and aging conditions. Precipitation kinetics can be improved by adding 0.5 wt% or 3.0 wt%Zn, while be suppressed after adding 1.5 wt%Zn. The Mg-Si precipitates (GP zones and β″) are still the main precipitates in the Al-Mg-Si-Cu alloys after heated up to 250 °C, and no Mg-Zn precipitates are observed in the Zn-added alloy due to the occurrence of Mg-Zn precipitates reversion. The measured age-hardening responses of the alloys are corresponding to the predicted results by the established precipitation kinetic equations. Additionally, a double-hump phenomenon of hardness appears in the artificial aging of pre-aged alloy with 3.0 wt% Zn addition, which resulted from the formation of pre-β″ and β″ precipitates. Finally, the precipitation mechanism of Al-Mg-Si-Cu alloys with different Zn contents was proposed based on the microstructure evolution and interaction forces between Mg, Si and Zn atoms.

  19. Effect of Ag on Sn–Cu and Sn–Zn lead free solders

    Directory of Open Access Journals (Sweden)

    Alam S.N.

    2015-06-01

    Full Text Available Lead and lead-containing compounds are considered as toxic substances due to their detrimental effect on the environment. Sn-based soldering systems, like Sn-Cu and Sn-Zn are considered as the most promising candidates to replace the eutectic Sn-Pb solder compared to other solders because of their low melting temperature and favorable properties. Eutectic Sn-0.7 wt.% Cu and near eutectic composition Sn-8 wt.% Zn solders have been considered here for study. For the Sn-Cu system, besides the eutectic Sn-0.7 wt.% Cu composition, Sn-1Cu and Sn-2Cu were studied. Three compositions containing Ag: Sn-2Ag-0.7Cu, Sn-2.5Ag-0.7Cu and Sn-4.5Ag-0.7Cu were also developed. Ag was added to the eutectic Sn-0.7 wt.% Cu composition in order to reduce the melting temperature of the eutectic alloy and to enhance the mechanical properties. For the Sn-Zn system, besides the Sn-8 wt.% Zn near eutectic composition, Sn-8Zn-0.05Ag, Sn-8Zn-0.1Ag and Sn-8Zn-0.2Ag solder alloys were developed. The structure and morphology of the solder alloys were analyzed using a scanning electron microscope (SEM, filed emission scanning electron microscope (FESEM, electron diffraction X-ray spectroscopy (EDX and X-ray diffraction (XRD. Thermal analysis of the alloys was also done using a differential scanning calorimeter (DSC. Trace additions of Ag have been found to significantly reduce the melting temperature of the Sn-0.7 wt.% Cu and Sn-8 wt.% Zn alloys.

  20. Thermal formation of atomic vacancies in {gamma} Cu-Zn

    Energy Technology Data Exchange (ETDEWEB)

    Macchi, Carlos [Instituto de Fisica de Materiales Tandil, Universidad Nacional del Centro de la Provincia de Buenos Aires, Pinto 399, B7000GHG Tandil (Argentina); Romero, Ricardo [Instituto de Fisica de Materiales Tandil, Universidad Nacional del Centro de la Provincia de Buenos Aires, Pinto 399, B7000GHG Tandil (Argentina); Comision de Investigaciones Cientificas de la Provincia de Buenos Aires, Pinto 399, B7000GHG Tandil (Argentina); Somoza, Alberto [Instituto de Fisica de Materiales Tandil, Universidad Nacional del Centro de la Provincia de Buenos Aires, Pinto 399, B7000GHG Tandil (Argentina) and Comision de Investigaciones Cientificas de la Provincia de Buenos Aires, Pinto 399, B7000GHG Tandil (Argentina)]. E-mail: asomoza@exa.unicen.edu.ar

    2006-02-15

    g positron annihilation lifetime spectroscopy, the temperature dependence of the formation of thermal vacancies in the {gamma} phase of the Cu-Zn alloy was studied. Thermal equilibrium measurements were made in situ between 135K and about 950K. The experimental data were interpreted in terms of the well-established positron two-state trapping model. From the evolution of the lifetime parameters between {approx}400K and {approx}800K, an Arrhenius plot for trapping rate, directly linked to the vacancy concentration, exhibits the usual linear behavior. As a result, a value for the vacancy formation enthalpy for the complex cubic structure studied was estimated at H{sub v}{sup f}=0.46+/-0.03eV.

  1. Effects of annealing on the ferromagnetism and photoluminescence of Cu-doped ZnO nanowires

    Science.gov (United States)

    Xu, H. J.; Zhu, H. C.; Shan, X. D.; Liu, Y. X.; Gao, J. Y.; Zhang, X. Z.; Zhang, J. M.; Wang, P. W.; Hou, Y. M.; Yu, D. P.

    2010-01-01

    Room temperature ferromagnetic Cu-doped ZnO nanowires have been synthesized using the chemical vapor deposition method. By combining structural characterizations and comparative annealing experiments, it has been found that both extrinsic (CuO nanoparticles) and intrinsic (Zn1-xCuxO nanowires) sources are responsible for the observed ferromagnetic ordering of the as-grown samples. As regards the former, annealing in Zn vapor led to a dramatic decrease of the ferromagnetism. For the latter, a reversible switching of the ferromagnetism was observed with sequential annealings in Zn vapor and oxygen ambience respectively, which agreed well with previous reports for Cu-doped ZnO films. In addition, we have for the first time observed low temperature photoluminescence changed with magnetic properties upon annealing in different conditions, which revealed the crucial role played by interstitial zinc in directly mediating high Tc ferromagnetism and indirectly modulating the Cu-related structured green emission via different charge transfer transitions.

  2. Relationship between color and composition of Cu-Mn-Zn alloys

    Institute of Scientific and Technical Information of China (English)

    张玉平; 张津徐; 吴建生

    2002-01-01

    The color of Cu-Mn-Zn alloys is quantitatively researched using the CIE L*a*b* color system. The color parameters such as L*, a* and b* are employed to describe the color and are measured by a spectrophotometer. Based on the color data of 46 experimental alloys, a series of formulae are established to correlate color parameters changed with the alloy composition. Therefore, the color of the ternary Cu-Mn-Zn alloys can be calculated and forecast easily. The results show that Mn plays a more important role in the color of Cu-Mn-Zn alloys than Zn does. In particular, the chroma values of ternary Cu-Mn-Zn alloys mainly depend on the Mn content.

  3. Improved photocatalytic activity of nanocrystalline ZnO by coupling with CuO

    Science.gov (United States)

    Xu, Linhua; Zhou, Yang; Wu, Zijun; Zheng, Gaige; He, Jiaojiao; Zhou, Yanjing

    2017-07-01

    Although ZnO as a photocatalyst has attracted wide attention in the word in recent years, it is still a big challenge to develop low-cost, visible-light responsive ZnO based photocatalysts which can be used on a large scale. In this work, the CuO/ZnO nanocomposites have been synthesized by a facile one-step hydrothermal method and the influence of CuO contents on the photocatalytic properties of the nanocomposites has been investigated. The crystalline phase of the CuO/ZnO nanocomposites is determined by X-ray diffraction (XRD); the morphology and microstructures of the samples are analyzed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The photocatalytic performance of the samples is tested using methylene blue (MB)dyes as the simulated pollutant under irradiation of a Xe lamp. Compared with pure ZnO, the photocatalytic activity of the CuO/ZnO nanocomposites is largely improved, especially for the sample prepared by the precursor solution with the molar ratio of Zn2+: Cu2+=2:1. The improvement of the photocatalytic activity is attributed to two main factors: (1) the band coupling improves the separation efficiency of photogenerated electrons and holes; (2) the utilization efficiency for solar energy is enhanced in the CuO/ZnO coupling system.

  4. Lattice sites of implanted Cu and Ag in ZnO

    CERN Document Server

    Wahl, Ulrich; Correia, J G; Agne, Thomas; Alves, E; Carvalho-Soares, João

    2006-01-01

    The group $\\textrm{I}$b impurities Cu and Ag on substitutional Zn sites are among possible candidates for p-type doping of ZnO. In order to explore possible lattice sites of Cu and Ag in ZnO the radioactive impurities $^{67}\\!$Cu and $^{111}\\!$Ag were implanted at doses of $4\\!\\times\\!10^{12}$cm$^{-2}\\to1\\!\\times\\!10^{14}$cm$^{-2}$ at 60 keV into ZnO single crystals. The emission channeling effects of $\\beta\\!^{-}$ -particles from the decay were studied by means of position-sensitive electron detectors, giving direct evidence that in the as-implanted state large fractions of Cu and Ag atoms (60--70% for Cu and 30% for Ag) occupy almost ideal substitutional Zn sites with root mean square (rms) displacements of 0.014--0.017 nm. However, following vacuum annealing at 600 °C and above both Cu and Ag were found to be located increasingly on sites that are characterized by large rms displacements (0.03--0.05 nm) from Zn sites. We conclude that in high-temperature treated ZnO Cu and Ag are most likely not simply re...

  5. Molecular Cloning and Expression Analysis of Cu/Zn SOD Gene from Gynura bicolor DC.

    Directory of Open Access Journals (Sweden)

    Xin Xu

    2017-01-01

    Full Text Available Superoxide dismutase is an important antioxidant enzyme extensively existing in eukaryote, which scavenges reactive oxygen species (ROS and plays an essential role in stress tolerance of higher plants. A full-length cDNA encoding Cu/Zn SOD was cloned from leaves of Gynura bicolor DC. by rapid amplification of cDNA ends (RACE. The full-length cDNA of Cu/Zn SOD is 924 bp and has a 681 bp open reading frame encoding 227 amino acids. Bioinformatics analysis revealed that belonged to the plant SOD super family. Cu/Zn SODs of the Helianthus annuus, Mikania micrantha, and Solidago canadensis var. scabra all have 86% similarity to the G. bicolor Cu/Zn SOD. Analysis of the expression of Cu/Zn SOD under different treatments revealed that Cu/Zn SOD was a stress-responsive gene, especially to 1-MCP. It indicates that the Cu/Zn SOD gene would be an important gene in the resistance to stresses and will be helpful in providing evidence for future research on underlying molecular mechanism and choosing proper postharvest treatments for G. bicolor.

  6. Cu-ZnO-C nanoreactors studied by in situ synchrotron SAXS spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Ching-I; Kang, Hsu-Ya [Department of Environmental Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Wang, H. Paul, E-mail: wanghp@mail.ncku.edu.tw [Department of Environmental Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Lin, Wei-Keng [Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Jeng, U-Ser; Su, Chiu-Hun [National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan (China)

    2011-04-15

    Research highlights: {yields} Cu-ZnO-C nanoreactors formed by carbonization of Cu{sup 2+}- and Zn{sup 2+}-starch complexes. {yields} A threshold temperature for growth of coreshell nanoparticles at 433 K observed by in situ SAXS. {yields} Cu-ZnO-C nanoreactors are very effective in catalytic partial oxidation of methanol. - Abstract: By small angle X-ray scattering (SAXS) spectroscopy, changes of electronic density of selected element can be determined. A size growth of Cu-ZnO nanoparticles encapsulated in the carbon shell during temperature-programmed carbonization of Cu{sup 2+}- and Zn{sup 2+}-starch (Cu-to-Zn ratio = 1) at 343-523 K was observed by in situ SAXS. The Cu-ZnO-C behaves like a nanoreactor for catalytic partial oxidation of methanol (POM) to yield H{sub 2}-rich product gas. It seems that the enhanced POM may be associated with the high collision frequency of methanol, oxygen (as O atoms) and copper catalytic species in the confined nanoreactor.

  7. Hydrogen motion in the Cu-H complex in ZnO

    Energy Technology Data Exchange (ETDEWEB)

    Boerrnert, Felix; Lavrov, E.V.; Weber, J. [Technische Universitaet Dresden (Germany)

    2008-07-01

    The Cu-H complex in ZnO consists of Cu on Zn site and a hydrogen atom bound to a nearby O atom with the O-H bond oriented in the basal plane of the hexagonal lattice to the c axis. The motion of hydrogen in the Cu-H complex is studied by the stress-induced dichroism. Stress applied at room temperature along [10 anti 10] results in an alignment of the Cu-H bond. The reorientation process was found to be thermally activated with the activation energy of 0.52{+-}0.04 eV. The connection of the hydrogen movement in the Cu-H complex with the hydrogen diffusion in ZnO is discussed and consequences for the existence of interstitial hydrogen in ZnO at room temperature are presented.

  8. P-Cu2O/n-ZnO nanowires on ITO glass for solar cells.

    Science.gov (United States)

    Zhang, Jin; Que, Wenxiu; Zhong, Peng; Zhu, Gangqiang

    2010-11-01

    In this paper, the fabrication and characterization of a heterojunction solar cell based on p-Cu2O/n-ZnO nanowires on ITO glass are presented. ZnO aligned nanocrystal seed layer is firstly prepared by RF magnetron sputtering technique, and then vertical ZnO nanowire arrays with an acicular crystal structure are obtained by using a chemical bath deposition processing. The results indicate that the ZnO nanowires with a diameter of about 50 nm and 500 nm in length can be easily obtained. The absorption and transmittance of the ZnO nanowires are studied. It is also noted that the Cu2O can fill well into the space between ZnO nanowires by an electrodeposition process. Furthermore, the effect of the Cu2O orientation on the cell performance is also presented.

  9. Ecotoxicity of nanoparticles of CuO and ZnO in natural water

    Energy Technology Data Exchange (ETDEWEB)

    Blinova, I., E-mail: irina.blinova@kbfi.e [Laboratory of Molecular Genetics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, Tallinn 12618 (Estonia); Ivask, A. [Laboratory of Molecular Genetics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, Tallinn 12618 (Estonia); Heinlaan, M. [Laboratory of Molecular Genetics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, Tallinn 12618 (Estonia); Estonian University of Life Sciences, Kreutzwaldi 5, Tartu 51014 (Estonia); Mortimer, M. [Laboratory of Molecular Genetics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, Tallinn 12618 (Estonia); Tallinn University of Technology, Akadeemia tee 15, Tallinn 12618 (Estonia); Kahru, A. [Laboratory of Molecular Genetics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, Tallinn 12618 (Estonia)

    2010-01-15

    The acute toxicity of CuO and ZnO nanoparticles in artificial freshwater (AFW) and in natural waters to crustaceans Daphnia magna and Thamnocephalus platyurus and protozoan Tetrahymena thermophila was compared. The L(E)C{sub 50} values of nanoCuO for both crustaceans in natural water ranged from 90 to 224 mg Cu/l and were about 10-fold lower than L(E)C{sub 50} values of bulk CuO. In all test media, the L(E)C{sub 50} values for both bulk and nanoZnO (1.1-16 mg Zn/l) were considerably lower than those of nanoCuO. The natural waters remarkably (up to 140-fold) decreased the toxicity of nanoCuO (but not that of nanoZnO) to crustaceans depending mainly on the concentration of dissolved organic carbon (DOC). The toxicity of both nanoCuO and nanoZnO was mostly due to the solubilised ions as determined by specific metal-sensing bacteria. - Natural waters remarkably reduced the toxicity of nanoCuO but not nanoZnO.

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

    Science.gov (United States)

    Fekiacova, Z; Cornu, S; Pichat, S

    2015-06-01

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

  11. Cu2ZnSnS4 absorption layers with controlled phase purity

    OpenAIRE

    Chia-Ying Su; Chiu -Yen Chiu; Jyh-Ming Ting

    2015-01-01

    We report the synthesis and characterization of Cu2ZnSnS4 (CZTS) with controlled phase purity. The precursor was first prepared using sequential electrodeposition of Cu, Zn, and Sn in different orders. The Cu/(Sn+Zn) ratio in each stacking order was also varied. The precursor was subjected to annealing at 200°C and sulfurization at 500°C in a 5%-H2S/Ar atmosphere for the formation of CZTS. The phase evolutions during the electrodeposition and annealing stages, and the final phase formation at...

  12. Improved photocatalytic activity of ZnO coupled CuO nanocomposites synthesized by reflux condensation method

    Energy Technology Data Exchange (ETDEWEB)

    Mageshwari, K. [Department of Electronic Engineering, Hanyang University, Seoul (Korea, Republic of); PG and Research Department of Physics, Kongunadu Arts and Science College, Coimbatore 641 029, Tamil Nadu (India); Nataraj, D. [Department of Physics, Bharathiar University, Coimbatore 641 046 (India); Pal, Tarasankar [Department of Chemistry, Indian Institute of Technology, Kharagpur 721 302 (India); Sathyamoorthy, R., E-mail: rsathya59@gmail.com [PG and Research Department of Physics, Kongunadu Arts and Science College, Coimbatore 641 029, Tamil Nadu (India); Park, Jinsub, E-mail: jinsubpark@hanyang.ac.kr [Department of Electronic Engineering, Hanyang University, Seoul (Korea, Republic of)

    2015-03-15

    Highlights: • CuO–ZnO nanocomposites were synthesized by reflux condensation method. • Photodegradation of methyl orange and methylene blue dyes was investigated. • Morphological studies show 3D flower-like CuO microspheres adorned with ZnO nanorods. • Optical analysis showed characteristic absorption bands of CuO and ZnO. • CuO–ZnO nanocomposites exhibited superior photocatalytic activity than CuO. - Abstract: Nanostructured CuO–ZnO nanocomposites were successfully synthesized for different Zn{sup 2+} concentrations by reflux condensation method without using any surfactant, and their photocatalytic activity was evaluated using methyl orange and methylene blue dyes under UV light irradiation. XRD revealed the formation of CuO–ZnO nanocomposites, composing of monoclinic CuO and hexagonal ZnO. XPS analysis revealed that CuO–ZnO nanocomposites are made up of Cu(II), Zn(II) and O. FESEM and TEM images showed that pure CuO exhibit 3D flower-like microstructure, while the CuO–ZnO nanocomposites prepared for different Zn{sup 2+} concentrations have 3D flower-like CuO, microstructure adorned with rod-like ZnO particles. UV–Vis DRS showed absorption bands corresponding to CuO and ZnO around 960 nm and 395 nm, respectively. PL spectra of CuO–ZnO nanocomposites exhibited reduced PL emissions compared to pure CuO, indicating the low recombination rate of photogenerated electrons and holes. Photodegradation assay revealed that catalytic activity of CuO–ZnO nanocomposites increased with Zn{sup 2+} concentration, and also effectively degrade methyl orange and methylene blue dyes when compared to pure CuO. The enhanced photocatalytic activity of CuO–ZnO nanocomposites were mainly ascribed to the reduced recombination and efficient separation of photogenerated charge carriers. The possible mechanism for the improved photocatalytic activity of CuO–ZnO nanocomposites was proposed.

  13. Cu2ZnSnSe4 thin films prepared by selenization of one-step electrochemically deposited Cu-Zn-Sn-Se precursors

    Science.gov (United States)

    Meng, Mingming; Wan, Lei; Zou, Peng; Miao, Shiding; Xu, Jinzhang

    2013-05-01

    In this research a non-vacuum strategy was reported in facile preparation of kesterite-type Cu2ZnSnSe4 (CZTSe) thin films via selenization of one-step electrochemically prepared Cu-Zn-Sn-Se precursors. The Cu-Zn-Sn-Se precursor films were prepared by electrochemical deposition from electrolytes containing CuSO4, ZnSO4, SnCl4 and H2SeO3, and the substrate is a Mo coated soda-lime glass. The CZTSe thin films were obtained by annealing the electrochemically deposited films in the selenium vapors at the temperature of 550 °C. The crystal phases, micro-structures, chemical compositions and optical properties of CZTSe films have been studied by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), inductively coupled plasma optical emission spectrometer (ICP-OES), Raman scattering spectrum, and UV-vis absorption spectroscopic means. The results revealed that the electrolytes with Cu:Zn:Sn:Se molar ratio of 3:70:20:3 yields nearly pure phase of kesterite, and a band gap of 0.94 eV was determined by spectroscopic measurements.

  14. Facile synthesis of Zn doped CuO hierarchical nanostructures: Structural, optical and antibacterial properties

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, Javed, E-mail: tariqjan84@gmail.com, E-mail: javed.suggau@iiu.edu.pk; Jan, Tariq, E-mail: tariqjan84@gmail.com, E-mail: javed.suggau@iiu.edu.pk; Ul-Hassan, Sibt; Umair Ali, M.; Abbas, Fazal [Laboratory of Nanoscience and Technology, Department of Physics, International Islamic University, H-10, Islamabad (Pakistan); Ahmed, Ishaq [Experimental Physics Labs, National Center for Physics, Islamabad (Pakistan); Mansoor, Qaisar; Ismail, Muhammad [Institute of Biomedical and Genetic Engineering (IBGE), Islamabad (Pakistan)

    2015-12-15

    Zn{sub x}Cu{sub 1−x}O (where x= 0, 0.01, 0.03, 0.05, 0.07 and 0.1 mol%) hierarchical nanostructures have been prepared via soft chemical route. X-ray diffraction (XRD) results of the synthesized samples reveal the monoclinic structure of CuO without any impurity related phases. The micro-structural parameters such as crystallite size and microstrain have been strongly influenced by Zn doping. Scanning electron microscope (SEM) analyses depict the formation of hierarchical nanostructures having average particle size in the range of 26-43 nm. The surface area of CuO nanostructures has been reduced systematically with the increase in Zn content which is linked with the variations in particle size. An obvious decrease in the optical band gap energy of the synthesized CuO hierarchical nanostructures has been observed with Zn doping which is assigned to the formation of shallow levels in the band gap of CuO and combined transition from oxygen 2p states to d sates of Cu and Zn ions. The bactericidal potency of the CuO hierarchical nanostructures have been found to be enhanced remarkably with Zn doping.

  15. ZnO:Cu nanorods with visible luminescence: copper induced defect levels and its luminescence dynamics

    Science.gov (United States)

    Raji, R.; Gopchandran, K. G.

    2017-02-01

    In this work, we report the synthesis of ZnO:Cu nanoparticles with rod-like morphology using co-precipitation method. X-ray diffraction analysis indicated that these ZnO:Cu nanoparticles has wurtzite structure with preferential growth along (1 0 1) crystal plane. The formation of additional defect levels in these particles on doping with Cu was investigated using Raman and fluorescence spectroscopy. The increase in intensity of E 1 (LO) mode observed at ~580 cm-1 in the Raman spectra of ZnO:Cu nanoparticles, confirmed the formation of additional defect levels in these nanoparticles on doping with Cu. The doping concentration was evident in the intensity of the additional Raman mode observed at ~280 cm-1 for the Cu doped nanoparticles. Photoluminescence spectra of Cu doped ZnO nanoparticles shows three visible emission peaks at 413, 435 and 531 nm along with a UV emission peak at 390 nm, whereas undoped ZnO nanoparticles showed only two peaks, at 389 and 582 nm. The shrinkage in band gap causing the emission of violet, blue and green colors on doping with Cu are attributed to the s-d and p-d exchange interactions between conduction band electrons of ZnO and localized d electrons of Cu ions, resulting in renormalization of band gap. The emission bands observed in these ZnO:Cu nanoparticles has been illustrated with a schematic energy level diagram.

  16. Cu{sub 2}ZnSnSe{sub 4} thin films prepared by selenization of co-electroplated Cu-Zn-Sn precursors

    Energy Technology Data Exchange (ETDEWEB)

    Chen Zhesheng, E-mail: zheshengchen@gmail.com [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Han Lei; Wan Lei [Research center for Photovoltaic System Engineering Ministry of Education, Hefei University of Technology, Hefei 230009 (China); Zhang Chunhui; Niu Haihong [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Xu Jinzhang, E-mail: xujz@lzu.edu.cn [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Research center for Photovoltaic System Engineering Ministry of Education, Hefei University of Technology, Hefei 230009 (China)

    2011-08-01

    A novel technique for growth of high quality Cu{sub 2}ZnSnSe{sub 4} (CZTSe) thin films is reported in our work. The CZTSe thin films were fabricated onto Mo layers by co-electroplating Cu-Zn-Sn precursors followed by annealing in the selenium vapors at the substrate temperature of 550 deg. C. The morphology and structure of CZTSe thin films were characterized using scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD) and Raman scattering spectrum, respectively. The results revealed that the single phase was in the CZTSe thin films, and the other impurities such as ZnSe and Cu{sub 2}SnSe{sub 3} were not existed though they were difficult to distinguish both from EDS and XRD.

  17. Cu 2ZnSnSe 4 thin films prepared by selenization of co-electroplated Cu-Zn-Sn precursors

    Science.gov (United States)

    Chen, Zhesheng; Han, Lei; Wan, Lei; Zhang, Chunhui; Niu, Haihong; Xu, Jinzhang

    2011-08-01

    A novel technique for growth of high quality Cu 2ZnSnSe 4 (CZTSe) thin films is reported in our work. The CZTSe thin films were fabricated onto Mo layers by co-electroplating Cu-Zn-Sn precursors followed by annealing in the selenium vapors at the substrate temperature of 550 °C. The morphology and structure of CZTSe thin films were characterized using scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD) and Raman scattering spectrum, respectively. The results revealed that the single phase was in the CZTSe thin films, and the other impurities such as ZnSe and Cu 2SnSe 3 were not existed though they were difficult to distinguish both from EDS and XRD.

  18. Selective hydrogenolysis of glycerol to propylene glycol on Cu-ZnO composite catalysts: structural requirements and reaction mechanism.

    Science.gov (United States)

    Wang, Shuai; Zhang, Yichi; Liu, Haichao

    2010-05-03

    Cu-ZnO catalysts were prepared by homogeneous coprecipitation with varying Cu/Zn atomic ratios (0.4-2:1). The catalysts were examined in selective hydrogenolysis of glycerol to propylene glycol. Although propylene glycol selectivities remained essentially constant (over 93%) on the different Cu-ZnO catalysts, the turnover frequencies changed markedly with the Cu/Zn ratio, and reached the greatest value at the ratio of 1:1. Such activity dependence on the Cu/Zn ratio was in parallel with the change in the interaction between Cu and ZnO and in the Cu microstrain, as a consequence of the effects on the crystalline phases of hydroxycarbonate precursors for the Cu-ZnO catalysts, reflecting the structural requirements for glycerol hydrogenolysis. The hydrogenolysis mechanism was also examined and apparently involves kinetically relevant glycerol dehydrogenation to glyceraldehyde on Cu-ZnO and subsequent glyceraldehyde dehydration and hydrogenation to propylene glycol. The mechanism is consistent with the observed superior activities of the more strained Cu particles, and the higher propylene glycol selectivities obtained at higher glycerol and hydrogen concentrations. These findings provide a rationale for the design of more effective Cu-based catalysts in selective hydrogenolysis of glycerol and other biomass-derived polyols, for example, by synthesis of highly strained Cu particles strongly interacting with ZnO or other oxide supports.

  19. Nanoparticles from Cu-Zn-Al shape memory alloys physically synthesized by ion milling deposition

    Energy Technology Data Exchange (ETDEWEB)

    Pavon, Luis Alberto Lopez [Universidad Autonoma de Nuevo Leon (UANL), Nuevo Leon (Mexico); Cuellara, Enrique Lopez; Castro, Alejandro Torres; Cruza, Azael Martinez de la [Universidad Autonoma de Nuevo Leon (CIIDIT/UANL), Nuevo Leon (Mexico). Centro de Innovacion, Investigacion y Desarrollo en Ingenieria y Tecnologia; Ballesteros, Carmen [Universidad Carlos III de Madrid, Madrid (Spain). Departamento de Fisica; Araujo, Carlos Jose de [Universidade Federal de Campina Grande (UFCG), Campina Grande, PB (Brazil). Departamento de Engenharia Mecanica

    2012-05-15

    In this research, an ion milling equipment was used to elaborate nanoparticles from Cu-Zn-Al alloys with shape memory effect. Two different compositions were used, target A: 75.22Cu-17.12Zn-7.66Al at % with an Ms of -9 deg C and target B: 76.18Cu-15.84Zn-7.98Al with an Ms of 20 degree C. Nanoparticles were characterized by High Resolution Transmission Electron Microscopy, Electron Diffraction and Energy Dispersive X-ray Spectroscopy. The obtained nanoparticles showed a small dispersion, with a size range of 3.2-3.5 nm. Their crystal structure is in good agreement with the bulk martensitic structure of the targets. In this sense, results on morphology, composition and crystal structure have indicated that it is possible to produce nanoparticles of CuZnAl shape memory alloys with martensitic structure in a single process using Ion Milling. (author)

  20. Toxicity of Nanoscale CuO and ZnO to Daphnia magna

    Institute of Scientific and Technical Information of China (English)

    ZHAO Hai-zhou; LU Guang-hua; XIA Jun; JIN Shao-ge

    2012-01-01

    The potential effects of nanoscale CuO(nCuO),nanoscale ZnO(nZnO)and their mixtures on Daphnia magna were investigated,including 48-h acute toxicity and 21-d chronic toxicity tests as well as a feeding experiment.The results of acute toxicity show that nCuO/nZnO mixture was the most toxic followed by nCuO and nZnO.The nanoparticles(NPs)inhibited both the growth and reproduction of Daphnia magna during the testing period.Concentration dependence was apparent in all the cases and the intrinsic rate of natural increase was confirmed to be a very sensitive parameter to NPs exposure.Binary mixture appeared to be more toxic than the corresponding individual exposures at most cases except for the feeding behavior.

  1. Enhanced Solar Photoelectrochemical Conversion Efficiency of ZnO:Cu Electrodes for Water-Splitting Application

    Directory of Open Access Journals (Sweden)

    Rekha Dom

    2013-01-01

    Full Text Available n-type ZnO:Cu photoanodes were fabricated by simple spray pyrolysis deposition technique. Influence of low concentration (range ~10−4–10−1% of Cu doping in hexagonal ZnO lattice on its photoelectrochemical performance has been investigated. The doped photoanodes displayed 7-time enhanced conversion efficiencies with respect to their undoped counterpart, as estimated from the photocurrents generated under simulated solar radiation. This is the highest enhancement in the solar conversion efficiency reported so far for the Cu-doped ZnO. This performance is attributed to the red shift in the band gap of the Cu-doped films and is in accordance with the incident-photon-current-conversion efficiency (IPCE measurements. Electrochemical studies reveal an n-type nature of these photoanodes. Thus, the study indicates a high potential of doped ZnO films for solar energy applications, in purview of the development of simple nanostructuring methodologies.

  2. Predictive GIS Model for Potential Mapping of Cu, Pb, Zn Mineralization

    Institute of Scientific and Technical Information of China (English)

    Tarik. B. Benomar; BIAN Fuling

    2006-01-01

    The geologic features indicative of Cu, Pb, Zn mineral deposits in a area are fractures (structure), and host rock sediments. Datasets used include Cu, Pb, Zn deposit points record, geological data, remote sensing imagery (Landsat TM5). The mineral potential of the study area is assessed by means of GIS based geodata integration techniques for generating predictive maps. GIS predictive model for Cu, Pb, Zn potential was carried out in this study area (Weixi) using weight of evidence. The weights of evidence modeling techniques is the data driven method in which the spatial associations of the indicative geologic features with the known mineral occurrences in the area are quantified, and weights statistically assigned to the geologic features. The best predictive map generated by this method defines 24% the area having potential for Cu, Pb, Zn mineralization further exploration work.

  3. Pitting Corrosion of Cu-Zn-Al Shape Memory Alloy in Simulated Uterine Fluid

    Institute of Scientific and Technical Information of China (English)

    Bangyi CHEN; Chenghao LIANG; Daojun FU

    2005-01-01

    Electrochemical test technology and surface analysis method were employed to investigate the pitting corrosion of Cu-Zn-Al shape memory alloy in simulated uterine fluid. The results showed that the breakage of the breakingrenovating equilibrium of surface layers resulted in the pitting corrosion of Cu-Zn-Al shape memory alloy in simulated uterine fluid. The development of pitting corrosion was controlled by dissolution of surface layers. The critical pitting corrosion potential was 1.70 VsCE. The kinetics equation for the development of pitting corrosion for Cu-Zn-Al shape memory alloy in simulated uterine fluid was i0=465.68 t-0.5+1.5. Pitting appearances of pits could be two types: tortoise-shell, and anomaly abscess. Cl- ion facilitated the pitting corrosion of Cu-Zn-Al shape memory alloy by competing adsorption and concentrating on alloy surface at high positive potential.

  4. Understanding the activity of Zn-Cu sites in methanol synthesis

    NARCIS (Netherlands)

    Batyrev, E.D.

    2013-01-01

    This thesis deals with the Cu/ZnO interaction in activated methanol synthesis catalysts. A combination of classical characterization techniques and surface science techniques was applied to probe the dynamic modification of catalyst structure upon the activation in hydrogen.

  5. Effect of precipitation on elastic modulus of Al-Zn-Mg-Cu-Li alloys

    Institute of Scientific and Technical Information of China (English)

    ZHAO Zhong-kui; ZHOU Tie-tao; LIU Pei-ying; LI Huan-xi; CHEN Chang-qi

    2006-01-01

    Al-5.6Zn-3.0Mg-1.6Cu-1.1Li-0.24Cr alloys and Al-8.0Zn-2.4Mg-2.4Cu-1.1Li-0.18Zr alloys (mass fraction, %) were aged by different processes. The microstructure and mechanical properties were determined by transmission electron microscopy(TEM),tensile test and Vicker's hardness test. The experimental results show that the most signified hardening is obtained by double-ageing or multi-ageing for the Al-Zn-Mg-Cu-Li alloys. The yield strength and the elastic modulus of the Li-containing alloys have relationships with ageing processes. The elastic modulus of Li-containing alloys decreases with the increment of precipitates though it is higher than that of Al-Zn-Mg-Cu alloy.

  6. Characterization of Cu-Zn Alloy Nanocrystalline Powders Prepared by Wire Electrical Explosion

    Institute of Scientific and Technical Information of China (English)

    WANG Qun; YANG Hai-Bin; GUO Wei-Li; ZOU Guang-Tian

    2000-01-01

    Nanocrystalline powders of Cu-Zn alloy in size ranging from 10 to 140nm was prepared from α-Cu-Zn alloy wire containing 39.8at.% Zn by an electrical explosion method. The particles are identified from x-ray diffraction as a mixture of the α,β,γ, and ε phases of Cu-Zn alloy. Most of the particles are hexagonal in shape, with only a small part being spherical and cubic. The composition of Zn in the explosion products varied from 6.9 to 45.2 at.% in different particles as determined by energy dispersive x-ray spectrometer. A possible mechanism for the formation of the alloy nanocrystalline powders is proposed, in which a redistribution process occurred caused by strong collision and diffusion between the two kinds of atoms during the powder formation.

  7. Enhanced wetting of Cu on ZnO by migration of subsurface oxygen vacancies

    DEFF Research Database (Denmark)

    Beinik, Igor; Helström, Matti; Jensen, Thomas Nørregaard

    2015-01-01

    Metal adhesion on metal oxides is strongly controlled by the oxide surface structure and composition, but lack of control over the surface conditions often limits the possibilities to exploit this in opto- and micro-electronics applications and heterogeneous catalysis where nanostructural control...... is of utmost importance. The Cu/ZnO system is among the most investigated of such systems in model studies, but the presence of subsurface ZnO defects and their important role for adhesion on ZnO have been unappreciated so far. Here we reveal that the surface-directed migration of subsurface defects affects...... the Cu adhesion on polar ZnO(0001) in the technologically interesting temperature range up to 550 K. This leads to enhanced adhesion and ultimately complete wetting of ZnO(0001) by a Cu overlayer. On the basis of our experimental and computational results we demonstrate a mechanism which implies...

  8. Physical characterization of Cu{sub 2}ZnGeSe{sub 4} thin films from annealing of Cu-Zn-Ge precursor layers

    Energy Technology Data Exchange (ETDEWEB)

    Buffière, M., E-mail: buffiere@imec.be [Imec—Partner in Solliance, Leuven (Belgium); Department of Electrical Engineering (ESAT), KU Leuven, Heverlee (Belgium); ElAnzeery, H. [Imec—Partner in Solliance, Leuven (Belgium); KACST-Intel Consortium Center of Excellence in Nano-manufacturing Applications (CENA), Riyadh (Saudi Arabia); Microelectronics System Design department, Nile University, Cairo (Egypt); Oueslati, S.; Ben Messaoud, K. [Imec—Partner in Solliance, Leuven (Belgium); KACST-Intel Consortium Center of Excellence in Nano-manufacturing Applications (CENA), Riyadh (Saudi Arabia); Department of Physics, Faculty of Sciences of Tunis, El Manar (Tunisia); Brammertz, G.; Meuris, M. [Imec Division IMOMEC — Partner in Solliance, Diepenbeek (Belgium); Institute for Material Research (IMO) Hasselt University, Diepenbeek (Belgium); Poortmans, J. [Imec—Partner in Solliance, Leuven (Belgium); Department of Electrical Engineering (ESAT), KU Leuven, Heverlee (Belgium)

    2015-05-01

    Cu{sub 2}ZnGeSe{sub 4} (CZGeSe) can be considered as a potential alternative for wide band gap thin film devices. In this work, CZGeSe thin films were deposited on Mo-coated soda lime glass substrates by sequential deposition of sputtered Cu, Zn and e-beam evaporated Ge layers from elemental targets followed by annealing at high temperature using H{sub 2}Se gas. We report on the effect of the precursor stack order and composition and the impact of the annealing temperature on the physical properties of CZGeSe thin films. The optimal layer morphology was obtained when using a Mo/Cu/Zn/Ge precursor stack annealed at 460 °C. We have observed that the formation of secondary phases such as ZnSe can be prevented by tuning the initial composition of the stack, the stack order and the annealing conditions. This synthesis process allows synthesizing CZGeSe absorber with an optical band gap of 1.5 eV. - Highlights: • Cu{sub 2}ZnGeSe{sub 4} (CZGeSe) thin films were deposited using a two-step process. • CZGeSe dense layers were obtained using a Mo/Cu/Zn/Ge precursor annealed at 460 °C. • Formation of ZnSe can be avoided by tuning the composition and order of the initial stack. • P-type CZGeSe absorber with an optical band gap of 1.5 eV was obtained.

  9. Cu/Zn superoxide dismutase expression in the postnatal rat brain following an excitotoxic injury

    Directory of Open Access Journals (Sweden)

    Faiz Maryam

    2005-06-01

    Full Text Available Abstract Background In the nervous system, as in other organs, Cu/Zn superoxide dismutase (Cu/Zn SOD is a key antioxidant enzyme involved in superoxide detoxification in normal cellular metabolism and after cell injury. Although it has been suggested that immature brain has a different susceptibility to oxidative damage than adult brain, the distribution and cell-specific expression of this enzyme in immature brain and after postnatal brain damage has not been documented. Methods In this study, we used immunohistochemistry and western blot to analyze the expression of Cu/Zn SOD in intact immature rat brain and in immature rat brain after an NMDA-induced excitotoxic cortical injury performed at postnatal day 9. Double immunofluorescence labelling was used to identify Cu/Zn SOD-expressing cell populations. Results In intact immature brain, Cu/Zn SOD enzyme was widely expressed at high levels in neurons mainly located in cortical layers II, III and V, in the sub-plate, in the pyriform cortex, in the hippocampus, and in the hypothalamus. Glial fibrillary acidic protein-positive cells only showed Cu/Zn SOD expression in the glia limitans and in scattered cells of the ventricle walls. No expression was detected in interfascicular oligodendroglia, microglia or endothelial cells. Following excitotoxic damage, neuronal Cu/Zn SOD was rapidly downregulated (over 2–4 hours at the injection site before neurodegeneration signals and TUNEL staining were observed. Later, from 1 day post-lesion onward, an upregulation of Cu/Zn SOD was found due to increased expression in astroglia. A further increase was observed at 3, 5 and 7 days that corresponded to extensive induction of Cu/Zn SOD in highly reactive astrocytes and in the astroglial scar. Conclusion We show here that, in the intact immature brain, the expression of Cu/Zn SOD was mainly found in neurons. When damage occurs, a strong and very rapid downregulation of this enzyme precedes neuronal degeneration

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

    Energy Technology Data Exchange (ETDEWEB)

    Fekiacova, Z.; Cornu, S. [INRA, UR 1119 Géochimie des Sols et des Eaux, F-13100 Aix en Provence (France); Pichat, S. [Laboratoire de Géologie de Lyon (LGL-TPE), Ecole Normale Supérieure de Lyon, CNRS, UMR 5276, 69007 Lyon (France)

    2015-06-01

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

  11. In Vitro Degradation Behavior of Ternary Mg-Zn-Se and Mg-Zn-Cu Alloys as Biomaterials

    Science.gov (United States)

    Persaud-Sharma, Dharam; Budiansky, Noah

    2013-01-01

    In this study, the corrosion behavior of Mg-Zn-Se and Mg-Zn-Cu alloys was investigated to evaluate their corrosion behavior related to use as implantable biomaterials. The corrosion behavior of these alloys and a commercially available Mg-Zn alloy were examined using static solution electrochemical testing, dynamic solution gravimetric testing, ion leaching testing, and microscopic evaluation. Fluctuations in the pH of the Dulbecco’s Modified Eagles Medium (DMEM) used for the gravimetric and ion leaching immersion testing were also recorded over the 30-day duration to assess whether the media conditions induced by the alloy degradation would permit for cellular survival. Weight loss experimentation and electrochemical tests revealed the Mg-Zn-Cu alloy to have the greatest corrosion rate. PMID:24465245

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-12-31

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

  13. Cu-implanted ZnO nanorods array film: An aqueous synthetic approach

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Ajaya Kumar, E-mail: ajayaksingh_au@yahoo.co.in [Department of Chemistry, Govt. VYT PG. Autonomous College Durg, Chhattisgarh (India); Thool, Gautam Sheel [Department of Chemistry, Govt. VYT PG. Autonomous College Durg, Chhattisgarh (India); Singh, R.S. [Department of Physics, Govt. D.T. College, Utai, Durg, Chhattisgarh (India); Singh, Surya Prakash, E-mail: spsingh@iict.res.in [Inorganic and Physical Chemistry Division, CSIR-Indian Institute of Chemical Technology, Uppal road, Tarnaka, Hyderabad 500007 (India)

    2015-01-05

    Highlights: • Cu doped ZnO nanorods were synthesized using low temperature aqueous solution method. • We demonstrated the capping action of TEA via theoretical simulation. • Raman analysis revealed the presence of tensile strain in Cu doped ZnO nanorods. • Growth rate was found to be high in Cu doped ZnO nanorods. - Abstract: Pure and Cu doped ZnO nanorods array are synthesized via two step chemical bath deposition method. The seed layer is prepared by successive ionic layer adsorption reaction (SILAR) method. The synthesized materials have been systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDAX), Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy and photoluminescence (PL) spectroscopy. SEM pictures show the existence of vertically well aligned hexagonal ZnO nanorods. EDAX spectrum confirms the presence of Cu in ZnO nanorods. High intense peak of (0 0 2) plane and E{sub 2}{sup high} mode for XRD and Raman spectrum respectively, suggest the ZnO nanorods are adopted c-axis orientation perpendicular to substrate. XRD and Raman analysis shows the presence of tensile strain in Cu doped ZnO nanorods. Effect of Cu doping on lattice constants, unit cell volume and Zn–O bond length of ZnO nanorods have also been studied. Room temperature PL measurement exhibits two luminescence bands in the spectra i.e. UV emission centered at 3.215 eV and a broad visible band. Theoretical investigation for capping action of triethanolamine is done by Hartree–Fock (HF) method with 3-21G basis set using Gaussian 09 program package.

  14. The Influences of CuO/ZnO Ratios on the Crystallization Characteristics Electrical and Magnetic Properties of CuxZn1−xO Powders

    Directory of Open Access Journals (Sweden)

    Kuan-Jen Chen

    2013-01-01

    Full Text Available This study synthesizes CuxZn1−xO powders using an aqueous solution method. The CuxZn1−xO powders with different content ratios of CuO and ZnO (CuO : ZnO = 1 : 2, 1 : 1, and 2 : 1 were formed. The crystalline characteristics and electrical and magnetic properties depended primarily on the mixing effect and oxygenation. The electrical resistance of C0.5Z0.5O (1.5×105 Ω/□ powder was lower than that of CuO (5.82×105 Ω/□ powder after ZnO mixing in CuO. This reduction was attributed to the substitution of Cu+ ions at Zn2+ sites or the formation of electron trapping defect centers. The concentration ratio of Cu2O phase in CuxZn1−xO powder mainly dominated the electrical resistance. The CuxZn1−xO has a diluted ferromagnetism (DFM and paramagnetism (PM. The electrical resistance of CuxZn1−xO decreased; the magnetic behavior increased instead. This study also analyzes the chemical binding of Cu0.5Zn0.5O powders to confirm the contribution of Cu+ ions to the electrical and magnetic properties.

  15. ZnO/Cu2S/ZnO Multilayer Films: Structure Optimization and Its Detail Data for Applications on Photoelectric and Photocatalytic Properties

    Directory of Open Access Journals (Sweden)

    Zhenxing Wang

    2017-01-01

    Full Text Available Monolayer Cu2S and ZnO, and three kinds of complex films, Cu2S/ZnO, ZnO/Cu2S, and ZnO/Cu2S/ZnO, were deposited on glass substrates by means of radio frequency (RF magnetron sputtering device. The impact of the thickness of ZnO and Cu2S on the whole transmittance, conductivity, and photocatalysis was investigated. The optical and electrical properties of the multilayer were studied by optical spectrometry and four point probes. Numerical simulation of the optical transmittance of the multilayer films has been carried out in order to guide the experimental work. The comprehensive performances of the multilayers as transparent conductive coatings were compared using the figure of merit. Compared with monolithic Cu2S and ZnO films, both the optical transmission property and photocatalytic performance of complex films such as Cu2S/ZnO and ZnO/Cu2S/ZnO change significantly.

  16. Growth and Raman scattering characterization of Cu2ZnSnS4 thin films

    OpenAIRE

    Fernandes, P. A.; Salomé, P M P; Cunha, A. F. da

    2009-01-01

    In the present work we report the results of the growth, morphological and structural characterization of Cu2ZnSnS4 (CZTS) thin films prepared by sulfurization of DC magnetron sputtered Cu/Zn/Sn precursor layers. The adjustment of the thicknesses and the properties of the precursors were used to control the final composition of the films. Its properties were studied by SEM/EDS, XRD and Raman scattering. The influence of the sulfurization temperature on the morphology, composition ...

  17. One-pot synthesis of Cu/ZnO/ZnAl2O4 catalysts and their catalytic performance in glycerol hydrogenolysis

    KAUST Repository

    Tan, Hua

    2013-01-01

    In this work, a series of Cu/ZnO/ZnAl2O4 catalysts with different metal molar fractions (Cu:Zn:Al) were successfully prepared using a one-pot method via the evaporation-induced self-assembly (EISA) of Pluronic P123 and the corresponding metal precursors. The catalysts were characterized using N2 adsorption, H2 temperature-programmed reduction (H2-TPR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectra (XPS). The catalytic properties of the resulting Cu/ZnO/ZnAl2O4 with different molar fractions of metals were investigated for the selective hydrogenolysis of glycerol to 1,2-propanediol (1,2-PDO). It was observed that the ZnAl2O 4 support exerts a strong positive effect on the catalytic activity of the copper-based catalysts, and the presence of ZnO further improves the catalytic activity of the Cu/ZnAl2O4 catalysts. The Cu/ZnO/ZnAl2O4 catalyst (Cu10Zn 30Al60, Cu/Zn/Al molar ratio is 10:30:60), which was the best catalyst, exhibited the highest yield (79%) of 1,2-PDO with 85.8% glycerol conversion and 92.1% 1,2-PDO selectivity at 180 °C reaction temperature in 80 wt% glycerol aqueous solution over 10 h reaction time. The high catalytic activity was attributed to the presence of the ZnAl2O4 support, the strong interaction between ZnO and Cu nanoparticles and the small particle size of ZnO and Cu. Moreover, the Cu/ZnO/ZnAl2O4 catalysts exhibited higher stability than Cu/ZnO and Cu/ZnO/Al2O 3 catalysts prepared by a co-precipitation method during consecutive cycling experiments, which is due to the high chemical and thermal stability of crystalline ZnAl2O4 under harsh reaction conditions. This journal is © The Royal Society of Chemistry.

  18. Solution-processed highly efficient Cu2ZnSnSe4 thin film solar cells by dissolution of elemental Cu, Zn, Sn, and Se powders.

    Science.gov (United States)

    Yang, Yanchun; Wang, Gang; Zhao, Wangen; Tian, Qingwen; Huang, Lijian; Pan, Daocheng

    2015-01-14

    Solution deposition approaches play an important role in reducing the manufacturing cost of Cu2ZnSnSe4 (CZTSe) thin film solar cells. Here, we present a novel precursor-based solution approach to fabricate highly efficient CZTSe solar cells. In this approach, low-cost elemental Cu, Zn, Sn, and Se powders were simultaneously dissolved in the solution of thioglycolic acid and ethanolamine, forming a homogeneous CZTSe precursor solution to deposit CZTSe nanocrystal thin films. Based on high-quality CZTSe absorber layer, pure selenide CZTSe solar cell with a photoelectric conversion efficiency of 8.02% has been achieved without antireflection coating.

  19. Double junction photoelectrochemical solar cells based on Cu2ZnSnS4/Cu2ZnSnSe4 thin film as composite photocathode

    Science.gov (United States)

    Zhu, L.; Qiang, Y. H.; Zhao, Y. L.; Gu, X. Q.

    2014-02-01

    A solvothermal method was used to synthesize Cu2ZnSnS4 (CZTS) and Cu2ZnSnSe4 (CZTSe) nanoparticles. CZTS/CZTSe bilayer films have been fabricated via a layer-by-layer blade coating process on the fluorine dope tin oxide (FTO) substrates. We converted conventional dye-sensitized solar cells (DSSCs) into double junction photoelectrochemical solar cells with the replacement of the Pt-coated counter electrode with the as-prepared films as composite photocathodes. Compared with conventional DSSCs, the cells show an increased short circuit current and power conversion efficiency.

  20. Non-blinking (Zn)CuInS/ZnS Quantum Dots Prepared by In Situ Interfacial Alloying Approach

    Science.gov (United States)

    Zhang, Aidi; Dong, Chaoqing; Li, Liang; Yin, Jinjin; Liu, Heng; Huang, Xiangyi; Ren, Jicun

    2015-10-01

    Semiconductor quantum dots (QDs) are very important optical nanomaterials with a wide range of potential applications. However, blinking behavior of single QD is an intrinsic drawback for some biological and photoelectric applications based on single-particle emission. Herein we present a rational strategy for fabrication of non-blinking (Zn)CuInS/ZnS QDs in organic phase through in situ interfacial alloying approach. This new strategy includes three steps: synthesis of CuInS QDs, eliminating the interior traps of QDs by forming graded (Zn)CuInS alloyed QDs, modifying the surface traps of QDs by introducing ZnS shells onto (Zn)CuInS QDs using alkylthiols as sulfur source and surface ligands. The suppressed blinking mechanism was mainly attributed to modifying QDs traps from interior to exterior via a step-by-step modification. Non-blinking QDs show high quantum yield, symmetric emission spectra and excellent crystallinity, and will enable applications from biology to optoelectronics that were previously hindered by blinking behavior of traditional QDs.

  1. Antiferromagnetism in YBa sub 2 Cu sub 3 O sub 6+x : Ga and Zn substitutions. Pt. 2. Zero field NMR of the Cu magnetic sites. [YBaCuGaO; YBaCuZnO

    Energy Technology Data Exchange (ETDEWEB)

    Mendels, P.; Alloul, H.; Arabski, J.; Collin, G. (Lab. de Physique des Solides, Univ. Paris Sud, 91 - Orsay (France)); Marucco, J.F. (Lab. des Composes Non Stoechiometriques, Univ. Paris Sud, 91 - Orsay (France))

    1990-11-15

    We present an extensive study of the antiferromagnetic state of YBa{sub 2}Cu{sub 3}O{sub 6+x} (0Cu zero field nuclear magnetic resonance (ZFNMR). Our experiments clearly demonstrate that hole doping in the CuO{sub 2} planes occurs only for x>0.2 and that the nuclear spin T{sub 1} is very short nearby doped holes. As for static magnetic disorder, we show that ZFNMR is a very local in-plane probe nearly insensitive to the stacking of the CuO{sub 2} antiferromagnetic sheets. No magnetic disorder occurs for x<0.2 within CuO{sub 2} planes. For x>0.2 a comparison with muon and neutron results is presented. Cu substitution by Ga and Zn do not affect markedly the AF order of the CuO{sub 2} sheet while intensity measurements clearly demonstrate that Zn does not substitute appreciably on the Cu(2) site. (orig.).

  2. Ca, Mg, Zn, Fe, Cu and Mn content of ass’s milk

    Directory of Open Access Journals (Sweden)

    Elisabetta Salimei

    2010-01-01

    Full Text Available The aim of this study was to determine Ca, Mg, Zn, Fe, Cu and Mn content of ass’s milk. Twenty four individual milk samples were collected from 4 lactating asses. During the experi- mental period milk samples were collected every 3 weeks interval, using a milking machine; asses were housed with the foals that were separated from the jennets 3 hours before milking. Milk was analysed for Ca, Mg, Zn, Fe, Cu and Mn content by atomic absorption spectrometry. The concentration mean (±SD of Ca Mg, Zn, Fe, and Cu were respectively 334.61±39.80, 58.46±8.43, 1.99±0.51, 1.15±0.52, 0.16±0.06 mg/kg. Mn was found only at trace level. Iron content of ass’s milk was the most variable ranging from 0.43 to 1.88 mg/kg. Correlation coefficients were positive and significant between Ca and Mg (r=0.63, Zn and Mg (r=0.45, Zn and Fe (r=0.49 and Zn and Cu (r=0.50. In this study, except for Fe, mean concentration of Ca, Mg, Zn, and Cu in ass’s milk was similar to those reported in literature for human milk.

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

    Indian Academy of Sciences (India)

    A I Oliva; J E Corona; R Patiño; A I Oliva-Avilés

    2014-04-01

    Zn- and Cu-doped CdS thin films were deposited onto glass substrates by the chemical bath technique. ZnCl2 and CuCl2 were incorporated as dopant agents into the conventional CdS chemical bath in order to promote the CdS doping process. The effect of the deposition time and the doping concentration on the physical properties of CdS films were investigated. The morphology, thickness, bandgap energy, crystalline structure and elemental composition of Zn- and Cu-doped CdS films were investigated and compared to the undoped CdS films properties. Both Zn- and Cu-doped CdS films presented a cubic crystalline structure with (1 1 1) as the preferential orientation. Lower values of the bandgap energy were observed for the doped CdS films as compared to those of the undoped CdS films. Zn-doped CdS films presented higher thickness and roughness values than those of Cu-doped CdS films. From the photoluminescence results, it is suggested that the inclusion of Zn and Cu into CdS crystalline structure promotes the formation of acceptor levels above the CdS valence band, resulting in lower bandgap energy values for the doped CdS films.

  4. Modification and inactivation of Cu,Zn-superoxide dismutase by the lipid peroxidation product, acrolein

    Directory of Open Access Journals (Sweden)

    Jung Hoon Kang

    2013-11-01

    Full Text Available Acrolein is the most reactive aldehydic product of lipidperoxidation and is found to be elevated in the brain whenoxidative stress is high. The effects of acrolein on the structureand function of human Cu,Zn-superoxide dismutase (SOD wereexamined. When Cu,Zn-SOD was incubated with acrolein, thecovalent crosslinking of the protein was increased, and the loss ofenzymatic activity was increased in a dose-dependent manner.Reactive oxygen species (ROS scavengers and copper chelatorsinhibited the acrolein-mediated Cu,Zn-SOD modification and theformation of carbonyl compound. The present study shows thatROS may play a critical role in acrolein-induced Cu,Zn-SODmodification and inactivation. When Cu,Zn-SOD that has beenexposed to acrolein was subsequently analyzed by amino acidanalysis, serine, histidine, arginine, threonine and lysine residueswere particularly sensitive. It is suggested that the modificationand inactivation of Cu,Zn-SOD by acrolein could be produced bymore oxidative cell environments. [BMB Reports 2013; 46(11:555-560

  5. Modification and inactivation of Cu,Zn-superoxide dismutase by the lipid peroxidation product, acrolein.

    Science.gov (United States)

    Kang, Jung Hoon

    2013-11-01

    Acrolein is the most reactive aldehydic product of lipid peroxidation and is found to be elevated in the brain when oxidative stress is high. The effects of acrolein on the structure and function of human Cu,Zn-superoxide dismutase (SOD) were examined. When Cu,Zn-SOD was incubated with acrolein, the covalent crosslinking of the protein was increased, and the loss of enzymatic activity was increased in a dose-dependent manner. Reactive oxygen species (ROS) scavengers and copper chelators inhibited the acrolein-mediated Cu,Zn-SOD modification and the formation of carbonyl compound. The present study shows that ROS may play a critical role in acrolein-induced Cu,Zn-SOD modification and inactivation. When Cu,Zn-SOD that has been exposed to acrolein was subsequently analyzed by amino acid analysis, serine, histidine, arginine, threonine and lysine residues were particularly sensitive. It is suggested that the modification and inactivation of Cu,Zn-SOD by acrolein could be produced by more oxidative cell environments.

  6. Damping performance of Cu-Zn-Al shape memory alloys in engineering structures

    Institute of Scientific and Technical Information of China (English)

    司乃潮; 孙克庆; 孙少纯; 刘海霞

    2004-01-01

    The stress strain curves of two CuZnAl shape memory alloys which have the martensitic transformation temperatures of 50 ℃ and -10 ℃ respectively, were measured by using electronic material tester after treated by different heat-treatment conditions. The results show that the area enclosed by hysteresis loop of the CuZnAl shape memory alloy in martensitic state is much larger than that of the alloy in austenitic state with super-elasticity at room temperature. Therefore, the former has better vibration attenuation effect. After being oil-quenched, waterquenched, and step-quenched, the CuZnAl alloy takes on more stable shape memory effect, better super-plasticity and superelasticity (pseudoelasticity). A CuZnAl shape memory alloy damper was designed, produced and installed to a 2-layer frame structure. In addition, the vibration experiments were made by dynamic data collecting analysis meter. The velocity of vibration attenuation of frame structure with CuZnAl shape memory alloy damper is much faster than that without it. And with the help of CuZnAl shape memory alloy damper, the attenuation period reduces to 1/10 of the original.

  7. Science Letters:Preparation of high-permeability NiCuZn ferrite

    Institute of Scientific and Technical Information of China (English)

    HU Jun; YAN Mi

    2005-01-01

    Appropriate addition of CuO/V2O5 and the reduction of the granularity of the raw materials particle decrease the sintering temperature ofNiZn ferrite from 1200 ℃ to 930 ℃. Furthermore, the magnetic properties of the NiZn ferrite prepared at low temperature of 930 ℃ is superior to that of the NiZn ferrite prepared by sintering at high temperature of 1200 ℃ because the microstructure of the NiZn ferrite sintered at 930 ℃ is more uniform and compact than that of the NiZn ferrite sintered at 1200 ℃.The high permeability of 1700 and relative loss coefficient tanδ//μi of 9.0×10-6 at 100 kHz was achieved in the (Ni0.17Zn0.63Cu0.20)Fe1.915O4 ferrite.

  8. Cu,Zn superoxide dismutase: cloning and analysis of the Taenia solium gene and Taenia crassiceps cDNA.

    Science.gov (United States)

    Parra-Unda, Ricardo; Vaca-Paniagua, Felipe; Jiménez, Lucia; Landa, Abraham

    2012-01-01

    Cytosolic Cu,Zn superoxide dismutase (Cu,Zn-SOD) catalyzes the dismutation of superoxide (O(2)(-)) to oxygen and hydrogen peroxide (H(2)O(2)) and plays an important role in the establishment and survival of helminthes in their hosts. In this work, we describe the Taenia solium Cu,Zn-SOD gene (TsCu,Zn-SOD) and a Taenia crassiceps (TcCu,Zn-SOD) cDNA. TsCu,Zn-SOD gene that spans 2.841 kb, and has three exons and two introns; the splicing junctions follow the GT-AG rule. Analysis in silico of the gene revealed that the 5'-flanking region has three putative TATA and CCAAT boxes, and transcription factor binding sites for NF1 and AP1. The transcription start site was a C, located at 22 nucleotides upstream of the translation start codon (ATG). Southern blot analysis showed that TcCu,Zn-SOD and TsCu,Zn-SOD genes are encoded by a single copy. The deduced amino acid sequences of TsCu,Zn-SOD gene and TcCu,Zn-SOD cDNA reveal 98.47% of identity, and the characteristic motives, including the catalytic site and β-barrel structure of the Cu,Zn-SOD. Proteomic and immunohistochemical analysis indicated that Cu,Zn-SOD does not have isoforms, is distributed throughout the bladder wall and is concentrated in the tegument of T. solium and T. crassiceps cysticerci. Expression analysis revealed that TcCu,Zn-SOD mRNA and protein expression levels do not change in cysticerci, even upon exposure to O(2)(-) (0-3.8 nmol/min) and H(2)O(2) (0-2mM), suggesting that this gene is constitutively expressed in these parasites.

  9. Electromigration of Sn-3Ag-0.5Cu and Sn-3Ag-0.5Cu-0.5Ce-0.2Zn solder joints with Au/Ni(P)/Cu and Ag/Cu pads

    Energy Technology Data Exchange (ETDEWEB)

    Lin, H.-J., E-mail: HJLin@itri.org.t [Institute of Materials Science and Engineering, National Taiwan University, 1 Roosevelt St. Sec. 4, Taipei 106, Taiwan (China); Industrial Technology Research Institute, Mechanical and Systems Research Laboratories, Hsinchu 310, Taiwan (China); Lin, J.-S., E-mail: JohnnyLin@itri.org.t [Industrial Technology Research Institute, Mechanical and Systems Research Laboratories, Hsinchu 310, Taiwan (China); Department of Mechanical Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka 565-0871 (Japan); Chuang, T.-H., E-mail: tunghan@ntu.edu.t [Institute of Materials Science and Engineering, National Taiwan University, 1 Roosevelt St. Sec. 4, Taipei 106, Taiwan (China)

    2009-11-13

    It has previously been established that adding 0.2 wt.% Zn into a Sn-3Ag-0.5Cu-0.5Ce alloy improves the mechanical properties and eliminates the problem of rapid whisker growth. However, no detailed studies have been conducted on electromigration behavior of Sn-3Ag-0.5Cu-0.5Ce-0.2Zn alloy. The electromigration damage in solder joints of Sn-3Ag-0.5Cu and Sn-3Ag-0.5Cu-0.5Ce-0.2Zn with Ag/Cu pads and Au/Ni(P)/Cu pads was studied after current stressing at room temperature with an average current density of 3.1 x 10{sup 4} A/cm{sup 2}. With additions of 0.5 wt.% Ce and 0.2 wt.% Zn, the electromigration processes of Sn-Ag-Cu solder joints were accelerated due to refinement of the solder matrix when joint temperature was around 80 deg. C. Since Ni is more resistant than Cu to diffusion driven by electron flow, solder joints of both alloys (Sn-3Ag-0.5Cu and Sn-3Ag-0.5Cu-0.5Ce-0.2Zn) with Au/Ni(P)/Cu pads possess longer current-stressing lifetimes than those with Ag/Cu pads.

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

    Directory of Open Access Journals (Sweden)

    Ragnarsdottir K Vala

    2008-10-01

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

  11. Characteristics Of Sn-Zn Cast Alloys With The Addition Of Ag And Cu

    Directory of Open Access Journals (Sweden)

    Gancarz T.

    2015-09-01

    Full Text Available The aim of this work was to study the effects of Ag and Cu on the thermal properties and microstructure of Sn-Zn-Ag-Cu cast alloys. Solders based on eutectic Sn-Zn containing 0.5 to 1.0 at.% of Ag and Cu were developed for wave soldering. DSC measurements were performed to determine the melting temperatures of the alloys. TMA and electrical resistivity measurements were performed between −50 and 150°C and between 30 and 150°C, respectively. Small precipitates of Cu5Zn8, CuZn4, and AgZn3 were observed in the microstructures, and their presence was confirmed by XRD measurements. The inclusion of Ag and Cu improved the electrical resistivity and increased the melting temperature, as well as the CTE, of the alloys. However, tests performed to measure the mechanical properties of the alloys demonstratedthat the addition of Ag and Cu caused the mechanical properties to decrease.

  12. Effects of Cu, Zn and Pb Combined Pollution on Soil Hydrolase Activities

    Directory of Open Access Journals (Sweden)

    FENG Dan

    2015-08-01

    Full Text Available To study the relations between soil enzyme activities and heavy metal pollution, the combined effects of Cu, Zn and Pb on the three hydrolase activities, including invertase(IN, urease(Uand alkaline phosphatase(ALPwere investigated via an orthogonal experiment. Results showed as the following: When the concentration of Cu was 400 mg·kg-1, the U and ALP activities were decreased 51% and 44%, separately; When Zn was at 500 mg·kg-1, IN and ALP activities were only decreased 3% and 9%, while U activity was increased; When Pb was at 500 mg·kg-1, IN and U activities were increased, while ALP activity was decreased 13%. As a whole, Cu was considered as the most remarkable influence factor for IN, U and ALP activity regardless of interactions among the heavy metals, Zn came second, and Pb mainly showed activation. Considering interactions, Cu×Zn could significantly influence U activity(P<0.05, effects of Cu×Pb and Cu×Zn on ALP activity were remarkable(95% confidence interval. The response of ALP activity was more sensitive than the other two enzymes. Soil ALP activity might be a sensitive tool for assessing the pollution degree of Cu.

  13. Study of Zn-Cu ferrite nanoparticles for LPG sensing.

    Science.gov (United States)

    Jain, Anuj; Baranwal, Ravi Kant; Bharti, Ajaya; Vakil, Z; Prajapati, C S

    2013-01-01

    Nanostructured zinc-copper mixed ferrite was synthesized using sol-gel method. XRD patterns of different compositions of zinc-copper ferrite, Zn(1-x)Cu(x)Fe2O4 (x = 0.0, 0.25, 0.50, 0.75), revealed single phase inverse spinel ferrite in all the samples synthesized. With increasing copper concentration, the crystallite size was found to be increased from 28 nm to 47 nm. The surface morphology of all the samples studied by the Scanning Electron Microscopy there exhibits porous structure of particles throughout the samples. The pellets of the samples are prepared for LPG sensing characteristics. The sensing is carried out at different operating temperatures (200, 225, and 250°C) with the variation of LPG concentrations (0.2, 0.4, and 0.6 vol%). The maximum sensitivity of 55.33% is observed at 250°C operating for the 0.6 vol% LPG.

  14. Preparation and Characterization of Cu2ZnSnS4 Thin Films and Solar Cells Fabricated from Quaternary Cu-Zn-Sn-S Target

    OpenAIRE

    2013-01-01

    CZTS thin films were fabricated through sputtering from a quaternary Cu-Zn-Sn-S target, followed by a sulfurization process. CZTS thin-film solar cells were also fabricated and a highest efficiency of 4.04% was achieved. It has been found that obvious Zn loss occurs during the sputtering and poorly crystallized CZTS are formed in the sputtered films. The Zn loss leads to the appearance of SnS. A sulfurization process can obviously improve the crystallinity of CZTS and films with grain size of...

  15. Analysis of CdS/CdTe devices incorporating a ZnTe:Cu/Ti Contact

    Energy Technology Data Exchange (ETDEWEB)

    Gessert, T.A. [National Renewable Energy Laboratory, 1617 Cole Blvd, Golden, Colorado 80401 (United States)]. E-mail: tim_gessert@nrel.gov; Asher, S. [National Renewable Energy Laboratory, 1617 Cole Blvd, Golden, Colorado 80401 (United States); Johnston, S. [National Renewable Energy Laboratory, 1617 Cole Blvd, Golden, Colorado 80401 (United States); Young, M. [National Renewable Energy Laboratory, 1617 Cole Blvd, Golden, Colorado 80401 (United States); Dippo, P. [National Renewable Energy Laboratory, 1617 Cole Blvd, Golden, Colorado 80401 (United States); Corwine, C. [National Renewable Energy Laboratory, 1617 Cole Blvd, Golden, Colorado 80401 (United States)

    2007-05-31

    High-performance CdS/CdTe photovoltaic devices can be produced using a ZnTe:Cu/Ti back contact deposited onto the CdTe layer. We observe that prolonged exposure of the ZnTe:Cu and Ti sputtering targets to an oxygen-containing plasma significantly reduces device open-circuit voltage and fill factor. High-resolution compositional analysis of these devices reveals that Cu concentration in the CdTe and CdS layers is lower for devices with poor performance. Capacitance-voltage analysis and related numerical simulations indicate that the net acceptor concentration in the CdTe is also lower for devices with poor performance. Photoluminescence analyses of the junction region reveal that the intensity of a luminescent peak associated with a defect complex involving interstitial Cu (Cu{sub i}) and oxygen on Te (O{sub Te}) is reduced in devices with poor performance. Combined with thermodynamic considerations, these results suggest that oxygen incorporation into the ZnTe:Cu sputtering target reduces the ability of sputtered ZnTe:Cu film to diffuse Cu into the CdTe.

  16. Geogenic distribution and baseline concentrations of Cu and Zn in surficial soil of Guiyang, China

    Institute of Scientific and Technical Information of China (English)

    WANG Ji; WANG Shijie; OUYANG Ziyuan; LI Ruiling

    2006-01-01

    This paper describes the environmentally geochemical characteristics of heavy metal pollu tants such as Cu and Zn in the surficial soil of Guiyang, the capital city of Guizhou Province. The baseline concentrations of heavy metals in soil and the geochemical norms have been established to distinguish natural or artificial influence on the environment. Using the statistically analytical methods, we have established the baseline of Cu in Guiyang ( 18.8 mg/kg) and the soil ( over 68.4 mg/kg) may suffer Cu contamination. The data of Zn are 46.3 mg/kg and 112.0 mg/kg. Geoaccumulation index analysis indicated that the surficial soil that has suffered non-pollution to mid-pollution of Cu accounts for 38%, 38%, and 22% for mid-pollution, and only 2% between mid-pollution to severe pollution. Surficial soil that has suffered non-pollution to mid-pollution of Zn accounts for 41%, 50%, and 7% for mid-pollution, and only 2% between mid-pollution to severe pollution. The maximal degree of Cu contamination is 5.09 in the surficial soil of Guiyang. Surficial soil that has not suffered Cu pollution accounts for 53.2%. The total pollution degree of Cu is slightly over zero. So the surficial soil of Guiyang has suffered slight Cu pollution. The maximum value of Zn contamination degree is 2.85 in the surficial soil of Guiyang. 77.8% of the surficial soil has not yet suffered any Zn pollution. The total pollution degree of Zn is less than zero.So the surficial soil in Guiyang is free from pollution of Zn.

  17. Preparation of highly oriented Al:ZnO and Cu/Al:ZnO thin films by sol-gel method and their characterization

    Energy Technology Data Exchange (ETDEWEB)

    Vijayaprasath, G.; Murugan, R. [School of Physics, Alagappa University, Karaikudi 630 004, Tamil Nadu (India); Mahalingam, T. [Department of Electrical and Computer Engineering, Ajou University, Suwon 443-749 (Korea, Republic of); Hayakawa, Y. [Research Institute of Electronics, Shizuoka University, Hamamatsu 432-8011 (Japan); Ravi, G., E-mail: gravicrc@gmail.com [School of Physics, Alagappa University, Karaikudi 630 004, Tamil Nadu (India)

    2015-11-15

    Highly oriented thin films of Al doped ZnO (Al:ZnO) and Cu co-doped Al:ZnO (Cu/Al:ZnO) thin films were successfully deposited by sol–gel spin coating on glass substrates. The deposited films were characterized using X-ray diffraction analysis and found to exhibit hexagonal wurtzite structure with c-axis orientation. SEM images revealed that hexagonal rod shaped morphologies were grown perpendicular to the substrate surface due to repeated deposition process. High transmittance values were observed for pure ZnO compared to Al:ZnO and Cu/Al:ZnO thin films. The band gap widening is caused by the increase of carrier concentration, which is believed to be due to Burstein-Moss effect due to Al and Cu doping. PL spectra of Cu/Al:ZnO thin films indicate that the UV emission peaks slightly shifted towards lower energy side. XPS study was carried out for Zn{sub 0.80}Al{sub 0.10}Cu{sub 0.10}O thin films to analyze the binding energy of Al, Cu, Zn and O. Magnetic measurement studies exhibited ferromagnetic behavior at room temperature, which may be due to the increase in copper concentration in the doped films. The ferromagnetic behavior can be understood from the exchange coupling between localized ‘d’ spin of Cu ion mediated by free delocalized carriers. - Highlights: • High quality of Al:ZnO and Cu co-doped Al:ZnO thin films were fabricated by sol–gel method. • The XRD analyses revealed that the deposited thin films have hexagonal wurtzite structure. • XPS was carried out for Zn{sub 0.80}Al{sub 0.10}Cu{sub 0.10}O films to analyze the binding energy of Al, Cu, Zn and O. • SEM studies were made for Al:ZnO and Cu/Al:ZnO thin films. • RTFM was observed in Cu co-doped Al:ZnO thin films.

  18. Synthesis and properties of ZnO-HMD@ZnO-Fe/Cu core-shell as advanced material for hydrogen storage.

    Science.gov (United States)

    Bouazizi, N; Boudharaa, T; Bargougui, R; Vieillard, J; Ammar, S; Le Derf, F; Azzouz, A

    2017-04-01

    In this paper, a new synthetic strategy towards functionalized ZnO-HMD@ZnO-Fe/Cu core-shell using sol-gel process modified by chemical grafting of hexamethylenediamine (HMD) on the core and in-situ dispersion of Cu(0)/Fe(0) as metallic nanoparticles (M-NPs) on the shell. The as-prepared core-shell materials were fully characterized by transmission electron microscopy, X-ray powder diffractometry, diffuse reflectance and FT-IR spectrophotometery, photoluminescence, and complexes impedance spectroscopy measurements. The XRD patterns agreed with that of the ZnO typical wurtzite structure, indicating good crystallinity of ZnO-HMD@ZnO-Fe/Cu, with the presence of Fe(0) and Cu(0) phases. Hexamethylenediamine grafting and M-NPs insertion were highly activated and enhanced the core and shell interface by the physiochemical interaction. After functionalization, luminescence intensities and electrical properties of both core and core-shell nanoparticles are improved, indicating the effects of the surface groups on the charge transfer of ZnO-HMD@ZnO-Fe/Cu. The hydrogen capacity retention was depended strongly on the composition and structure of the obtained core-shell. Iron/Copper-loaded ZnO-HMD@ZnO materials exhibited the highest capacity for hydrogen storage. The excellent stability and performance of the ZnO-HMD@ZnO-Fe/Cu core-shell make it an efficient candidate for hydrogen storage.

  19. [Speciation analysis of trace elements Cu, Fe and Zn in serum by flame atomic absorption spectrophotometry].

    Science.gov (United States)

    Hu, Jun; Chang, Yao-Ming; Gao, Shuang-Bin; Hai, Chun-Xu; Li, Jin-Sheng; Xie, Xiao-Ping

    2008-03-01

    Since biological functions of the elements are generally different, depending on their chemical forms, chemical speciation analysis is really important in metallomics research. Thus, multielement analysis and chemical speciation of the elements in serum were carried out in the present work. A hyphenated technique was developed for high-throughput speciation analysis of the copper, iron and zinc in serum by molecular biology technology and flame atomic absorption spectrophotometry (AAS). Here, Cu, Fe and Zn in serum were classifyied as the forms of combination and non-combination. The serum protein was precipitated by 60% concentration of ethanol under hypothermy. The forms of combination of Cu, Fe and Zn in serum which combined with proteins were in precipitations, and the forms of non-combination of Cu, Fe and Zn in serum, which were free ions, were in supernatant. The total amount of Cu, Fe and Zn in serum and the amount of the forms of non-combination of Cu, Fe and Zn were analyzed by AAS. The amount of the forms of combination of Cu, Fe and Zn was obtained by calculation. The detection limit of Cu in serum by the method is around and 9.84 x 10(-3) microg x mL(-1). For Fe and Zn, the detection limit is about 2.76 x 10(-2) microg x mL(-1) and 1.06 x 10(-3) microg x mL(-1), respectively. The percentage recovery of trace elements Cu, Fe and Zn by the proposed procedure is in the range 95.0%-101.0%, 95.0%-102.0% and 95.0%-103.0%, respectively. The relative standard deviation (RSD) of trace elements Cu, Fe and Zn in the serum is in the range 1.88%-2.26%, 0.56%-1.59% and 0.34%-1.36%, respectively. Speciation of trace elements Cu, Fe and Zn in the serum of SD rat were analyzed by the method.

  20. Atom exchange of martensite in Cu-13Zn-15Al alloy during non-isothermal aging

    Institute of Scientific and Technical Information of China (English)

    LI Zhou; XIAO Zhu; BAO Ji-qing; XU Gen-ying; ZHENG Feng

    2006-01-01

    The bulk specimens with preferable orientation were utilized to investigate atom exchange of martensite in Cu-13Zn-15Al alloy during non-isothermal aging by in-situ X-ray diffraction. It is found that the exchange of Zn atoms at position Ⅲ and Cu atoms at Ⅱ and the exchange of Zn atoms at position Ⅲ and Al atoms atⅠon the basal plane of martensite occur during heating at a heating rate of 5 ℃/min. 13% (2/25 ) of Al atoms transfer from positionⅠto position Ⅲ when temperature goes up to 160 ℃.

  1. Complete transformation of ZnO and CuO nanoparticles in culture medium and lymphocyte cells during toxicity testing.

    Science.gov (United States)

    Ivask, Angela; Scheckel, Kirk G; Kapruwan, Pankaj; Stone, Vicki; Yin, Hong; Voelcker, Nicolas H; Lombi, Enzo

    2017-03-01

    Here, we present evidence on complete transformation of ZnO and CuO nanoparticles, which are among the most heavily studied metal oxide particles, during 24 h in vitro toxicological testing with human T-lymphocytes. Synchrotron radiation-based X-ray absorption near edge structure (XANES) spectroscopy results revealed that Zn speciation profiles of 30 nm and 80 nm ZnO nanoparticles, and ZnSO4- exposed cells were almost identical with the prevailing species being Zn-cysteine. This suggests that ZnO nanoparticles are rapidly transformed during a standard in vitro toxicological assay, and are sequestered intracellularly, analogously to soluble Zn. Complete transformation of ZnO in the test conditions was further supported by almost identical Zn spectra in medium to which ZnO nanoparticles or ZnSO4 was added. Likewise, Cu XANES spectra for CuO and CuSO4-exposed cells and cell culture media were similar. These results together with our observation on similar toxicological profiles of ZnO and soluble Zn, and CuO and soluble Cu, underline the importance of dissolution and subsequent transformation of ZnO and CuO nanoparticles during toxicological testing and provide evidence that the nano-specific effect of ZnO and CuO nanoparticles is negligible in this system. We strongly suggest to account for this aspect when interpreting the toxicological results of ZnO and CuO nanoparticles.

  2. Effects of Cu2+ and Zn2+ on growth of Triticum aestivum seedling%Cu2+和Zn2+对普通小麦幼苗生长的影响

    Institute of Scientific and Technical Information of China (English)

    李进学; 曹虎; 张芬琴; 李彩霞

    2005-01-01

    The effects of Cu2+ and Zn2+ on growth and physiological characters of Triticum aestivum Linn. seedling were studied. The resultsindicatedthat the higherconcentration ofCu2+ andZn2+ hadobvious inhibition, showing that the content of chlorophyll was reduced, the content of MDA and electrical conductivity increased, the vigor of root reduced. It showed that the effect of Cu2+ on T. aestivum was more poisonous than that of Zn2+.

  3. The energies of formation and mobilities of Cu surface species on Cu and ZnO in methanol and water gas shift atmospheres studied by DFT

    DEFF Research Database (Denmark)

    Rasmussen, Dominik Bjørn; Janssens, Ton V.W.; Temel, Burcin;

    2012-01-01

    ) species are investigated in relevant synthesis gas compositions. The CuCO and Cu2HCOO species are identified to be predominant for metal transport on Cu particles, which may contribute to sintering of Cu by particle migration and coalescence. Furthermore, transport of Cu on ZnO is found mostly to occur......Catalysts based on copper, such as the Cu/ZnO/Al2O3 system are widely used for industrial scale methanol synthesis and the low temperature water gas shift reaction. A common characteristic of these catalysts is that they deactivate quite rapidly during operation and therefore understanding...... through CuCO species, which indicates that CuCO is an important species for Ostwald ripening in a Cu/ZnO catalyst. These results provide atomistic perspective on the diffusion of the species that may contribute to catalyst sintering, therefore lending a valuable foundation for future investigations...

  4. Comparative Study of the Defect Point Physics and Luminescence of the Kesterites Cu2ZnSnS4 and Cu2ZnSnSe4 and Chalcopyrite Cu(In,Ga)Se2: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Romero, M. J.; Repins, I.; Teeter, G.; Contreras, M.; Al-Jassim, M.; Noufi, R.

    2012-08-01

    In this contribution, we present a comparative study of the luminescence of the kesterites Cu2ZnSnS4 (CZTS) and Cu2ZnSnSe4 (CZTSe) and their related chalcopyrite Cu(In,Ga)Se2 (CIGSe). Luminescence spectroscopy suggests that the electronic properties of Zn-rich, Cu-poor kesterites (both CZTS and CZTSe) and Cu-poor CIGSe are dictated by fluctuations of the electrostatic and chemical potentials. The large redshift in the luminescence of grain boundaries in CIGSe, associated with the formation of a neutral barrier is clearly observed in CZTSe, and, to some extent, in CZTS. Kesterites can therefore replicate the fundamental electronic properties of CIGSe.

  5. Heterojunction formation in (CdZn)S/CuInSe2 ternary solar cells

    Science.gov (United States)

    Ahrenkiel, R. K.; Kazmerski, L. L.; Matson, R. J.; Osterwald, C.; Massopust, T. P.; Mickelsen, R. A.; Chen, W. S.

    1983-10-01

    The electrical properties of (CdZn)S/CuInSe2 solar cells have been investigated by combining electron beam induced current measurements and capacitance-voltage measurements on the same device. In the as-grown device, the CuInSe2 is lightly doped n type. After baking to about 225 C in vacuum, the CuInSe2 converts to p type forming the heterojunction. Oxygen does not appear to be necessary for type conversion to occur.

  6. Study of polycrystalline Cu2ZnSnS4 films by Raman scattering

    OpenAIRE

    Fernandes, P. A.; Salomé, P M P; Cunha, A. F. da

    2011-01-01

    Cu2ZnSnS4 (CZTS) is a p-type semiconductor that has been seen as a possible low-cost replacement for Cu(In,Ga)Se2 in thin film solar cells. So far compound has presented difficulties in its growth, mainly, because of the formation of secondary phases like ZnS, CuxSnSx+1, SnxSy, Cu2−xS and MoS2. X-ray diffraction analysis (XRD), which is mostly used for phase identification cannot resolve some of these phases from the kesterite/stannite CZTS and thus the use of a complementary tech...

  7. ZnO/Cu nanocomposite: a platform for direct electrochemistry of enzymes and biosensing applications.

    Science.gov (United States)

    Yang, Chi; Xu, Chunxiang; Wang, Xuemei

    2012-03-06

    Unique structured nanomaterials can facilitate the direct electron transfer between redox proteins and the electrodes. Here, in situ directed growth on an electrode of a ZnO/Cu nanocomposite was prepared by a simple corrosion approach, which enables robust mechanical adhesion and electrical contact between the nanostructured ZnO and the electrodes. This is great help to realize the direct electron transfer between the electrode surface and the redox protein. SEM images demonstrate that the morphology of the ZnO/Cu nanocomposite has a large specific surface area, which is favorable to immobilize the biomolecules and construct biosensors. Using glucose oxidase (GOx) as a model, this ZnO/Cu nanocomposite is employed for immobilization of GOx and the construction of the glucose biosensor. Direct electron transfer of GOx is achieved at ZnO/Cu nanocomposite with a high heterogeneous electron transfer rate constant of 0.67 ± 0.06 s(-1). Such ZnO/Cu nanocomposite provides a good matrix for direct electrochemistry of enzymes and mediator-free enzymatic biosensors.

  8. Research on a Zn-Cu alloy as a biodegradable material for potential vascular stents application.

    Science.gov (United States)

    Niu, Jialin; Tang, Zibo; Huang, Hua; Pei, Jia; Zhang, Hua; Yuan, Guangyin; Ding, Wenjiang

    2016-12-01

    Zn-based alloys have been viewed as new potential materials for biodegradable implants, such as cardiovascular stents, mainly in consideration of their lower corrosion rate when compared with that of Mg alloys. In this study we developed a new Zinc-4wt.%Copper (Zn-4Cu) alloy as a biodegradable material. Hot extrusion was applied to Zn-4Cu to refine the microstructure and consequently improve its mechanical properties and corrosion resistance. After extrusion, dendritic CuZn5 phases were broken and distributed along the extrusion direction. The grains were refined obviously due to dynamical recrystallization. The yield strength (YS), ultimate tensile strength (UTS) and elongation of the as-extruded alloy are 250±10MPa, 270±10MPa and 51±2%, respectively. The corrosion rate of the as-extruded alloy in Hank's solution is about 9.41(±1.34)μmyear(-1). In vitro evaluation shows that Zn-4Cu presents acceptable toxicity to human endothelial cells, and could effectively inhibit bacteria adhesion and biofilm formation. The present study indicates that the as-extruded Zn-4Cu alloy exhibits excellent strength and ductility, uniform and slow degradation, good biocompatibility and significant antibacterial effect, which make it an excellent candidate material for biodegradable implants, especially for cardiovascular stents application.

  9. Facile synthesis of ZnO/CuInS2 nanorod arrays for photocatalytic pollutants degradation.

    Science.gov (United States)

    Yang, Yawei; Que, Wenxiu; Zhang, Xinyu; Xing, Yonglei; Yin, Xingtian; Du, Yaping

    2016-11-05

    Vertically-aligned ZnO nanorod arrays on a fluorine-doped tin oxide glass substrate were homogeneously coated with visible light active CuInS2 quantum dots by using a controllable electrophoretic deposition strategy. Compared with the pure ZnO nanorod arrays, the formation of high-quality ZnO/CuInS2 heterojunction with well-matched band energy alignment expanded the light absorption from ultraviolet to visible region and facilitated efficient charge separation and transportation, thus yielding remarkable enhanced photoelectrochemical performance and photocatalytic activities for methyl orange and 4-chlorophenol degradation. The ZnO/CuInS2 film with the deposition duration of 80min showed the highest degradation rate and photocurrent density (0.95mA/cm(2)), which was almost 6.33 times higher than that of the pure ZnO nanorod arrays film. The CuInS2 QDs sensitized ZnO nanorod arrays film was proved to be a superior structure for photoelectrochemical and photocatalytic applications due to the optimized CuInS2 loading and well-maintained one-dimensional nanostructure.

  10. Cu(I)/SO2-4/ZnO和Cu(I)/S2O2-8/ZnO催化剂的制备与表征%Preparation and Characterization of Cu(Ⅰ)/SO2-4/ZnO and Cu(Ⅰ)/S2O2-8/ZnO Catalysts

    Institute of Scientific and Technical Information of China (English)

    李忠; 黄海彬; 谢克昌

    2008-01-01

    采用浸渍法对无定形ZnO分别用稀H2SO4和(NH4)2S2O8溶液处理,制备了SO2-4/ZnO和S2O2-8/ZnO固体酸.通过固体离子交换法制备了Cu(Ⅰ)/SO2-4/ZnO和Cu(Ⅰ)/S2O2-8/ZnO两种催化剂,并采用XRD,FTIR,TPD和TPR等进行了表征.研究结果表明,用稀H2SO4和(NH4)2S2O8溶液分别浸渍处理无定形ZnO,经过500~600 ℃高温焙烧后得到的SO2-4/ZnO和S2O2-8/ZnO固体酸表面形成了Zn3O(SO4)2物种;py-FTIR结果表明,两者均具有B酸中心和L酸中心,进一步的NH3-TPD研究结果证明,制备的固体酸NH3脱附峰均出现在543 ℃附近,属于高强度固体酸.结构分析认为,由于SO2-4强烈的电子诱导作用,SO2-4和ZnO形成的桥式配位物种产生了B酸中心和L酸中心,而其螯合配位形成的物种没有酸性.SO2-4/ZnO和S2O2-8/ZnO固体酸与CuCl进行离子交换所制备的Cu(Ⅰ)/SO2-4/ZnO和Cu(Ⅰ)/S2O2-8/ZnO催化剂的Cu(Ⅰ)易于还原,对甲醇氧化羰基化合成碳酸二甲酯(DMC)表现出较高的活性和选择性,DMC选择性为98.3%,时空收率可达到1.9 g(g\\5h).

  11. Magnetic properties of ZnO:Cu thin films prepared by RF magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Zhuo Shiyi; Xiong Yuying; Gu Min, E-mail: xiongyy@scnu.edu.c [Laboratory of Quantum Information Technology, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006 (China)

    2009-05-01

    ZnO films and ZnO:Cu diluted magnetic semiconductor films were prepared by radio frequency magnetron sputtering on Si (111) substrates, with targets of ZnO and Zn{sub 0.99}Cu{sub 0.01}O, respectively. The plasma emission spectra were analyzed by using a grating monochromator during sputtering. The X-ray photoelectron spectroscopy measurements indicate the existence of Zni defect in the films, and the valence state of Cu is 1+. The X-ray diffraction measurements indicate that the thin films have a hexagonal wurtzite structure and have a preferred orientation along the c-axis. The vibrating sample magnetometer measurements indicate that the sample is ferromagnetic at room temperature, and the origin of the magnetic behavior of the samples is discussed.

  12. Accumulation of Cu and Zn in discarded antifouling paint particles by the marine gastropod, Littorina littorea

    Science.gov (United States)

    Gammon, Melanie; Turner, Andrew; Brown, Murray T.

    2009-10-01

    The short-term (5 day) accumulation of Cu and Zn in different tissues of the marine gastropod, Littorina littorea, has been studied in the presence of ˜10 mg l -1 of antifouling paint particles and pre- or simultaneously contaminated algal food ( Ulva lactuca). Accumulation of Cu was observed in the head-foot, digestive gland-gonad complex and gills to extents dependent on how and when food was contaminated and administered. However, retention of Zn was only observed in the gills and only when L. littorea and U. lactuca were simultaneously exposed to paint particles. Relative to the alga, faecal material was highly enriched in Zn, suggesting that the animal is able to rapidly eliminate this metal, most likely through the formation and egestion of insoluble phosphate granules. Thus, L. littorea is a useful biomonitor of marine contamination by antifouling applications in respect of Cu but not Zn.

  13. Magnetic properties of ZnO:Cu thin films prepared by RF magnetron sputtering

    Institute of Scientific and Technical Information of China (English)

    Zhuo Shiyi; Xiong Yuying; Gu Min

    2009-01-01

    ZnO films and ZnO:Cu diluted magnetic semiconductor films were prepared by radio frequency magnetron sputtering on Si (111) substrates, with targets of ZnO and Zn0.99Cu0.01 O, respectively. The plasma emission spectra were analyzed by using a grating monochromator during sputtering. The X-ray photoelectron spectroscopy measurements indicate the existence of Zni defect in the films, and the valence state of Cu is 1. The X-ray diffraction measurements indicate that the thin films have a hexagonal wurtzite structure and have a preferred orientation along the c-axis. The vibrating sample magnetometer measurements indicate that the sample is ferromagnetic at room temperature, and the origin of the magnetic behavior of the samples is discussed.

  14. Influence of Zn Addition on Microstructures and Martensitic Transformation in CuZr-based Alloys

    Institute of Scientific and Technical Information of China (English)

    Kai-kai SONG; Dian-yu WU; Feng WAN; Xiao-jun BAI; Chong-de CAO

    2016-01-01

    Compositional dependences on microstructures and martensitic transformation behaviors in (Cu0.5 Zr0.5 )100-x Znx (x =1.5,2.5,4.5,7.0,10.0,and 14.0 at.%)alloys were investigated.It was found that CuZr martensites were present in the present alloys.With increasing Zn content,the volume fractions of CuZr martensitic crystals and B2 CuZr phase gradually decrease and increase,respectively.With the addition of high Zn contents (i.e.,7.0,10.0, and 14.0 at.%),the matrix proves to be eutectic.Thermal analysis results show that the initial martensitic transfor-mation temperature (Ms)decreases from (412±5)K to (329±5)K as the Zn content increases from 1.5 at.% to 14.0 at.%.The values of Ms of Cu-Zr-Zn shape memory alloys are inversely proportional to the number and concen-trations of valence electrons (i.e.,e v/a and c v ),respectively,implying that the martensitic transformation in CuZr-Zn alloys could be of electronic nature.

  15. Determination of the band offset for the heterostructure ZnO/Cu{sub 2}O and ZnS/Cu{sub 2}O via X-ray photoelectron spektroscopy (XPS)

    Energy Technology Data Exchange (ETDEWEB)

    Kramm, Benedikt; Laufer, Andreas; Kronenberger, Achim; Graubner, Swen; Reppin, Daniel; Seibert, Alba; Schurig, Philipp; Polity, Angelika; Meyer, Bruno K. [1. Physikalisches Institut, Justus-Liebig-Universitaet, Heinrich-Buff-Ring 16, 35392 Giessen (Germany)

    2011-07-01

    ZnO and Cu{sub 2}O are direct band-gap semiconductors. Both are promising materials for electronic devices like diodes, transistors or solar cells. Important is, that ZnO and Cu{sub 2}O contain only non toxic und sustainable elements. Due to a band-gap energy of 2.1 eV for Cu{sub 2}O a high absorption in the visible light spectrum could be obtained which is suitable for solar cells. We produced a heterojunction of intrinsic p-type Cu{sub 2}O and hydrogen doped n-type ZnO or ZnS on sapphire using sputter deposition. Investigating the energy band structure of the thin film heterojunction ZnO/Cu{sub 2}O via XPS yield to be a type II alignment with a valence-band offset between 2.4 - 2.7 eV. Furthermore the band offset between ZnS and Cu{sub 2}O, using ZnS as a buffer-layer for the heterostructure ZnO/ZnS/Cu{sub 2}O, was explored. For the band offset structure of the whole system the band offset values for ZnS/ZnO, determined by Persson, have been used.

  16. Catalytic properties of Cu/Co/Zn/Zr oxides prepared by various methods

    Institute of Scientific and Technical Information of China (English)

    Limin Shi; Wei Chu; Siyu Deng; Huiyuan Xu

    2008-01-01

    The new Cu-Co based (Cu/Co/Zn/Zr) catalysts for higher-alcohol synthesis were prepared using coprecipitation method, plasma enhanced method and reverse coprecipitation method under ultrasound irradiation. The catalysts were investi-gated by the means of BET, SEM, XRD, H2-TPR and XPS. Catalytic properties of the catalysts prepared by various methods were examined using CO hydrogenation reaction. It was found that plasma enhanced method and reverse coprecipitation method under ultrasound irradiation were both effective in enhancing the catalytic properties of Cu/Co/Zn/Zr mixed oxides. The small particle size, high dispersion of active components, the improvement of specific surface area and surface contents of active phases could account for the excellent performance of the experimental Cu/Co/Zn/Zr catalysts.

  17. Effect of the Zn(II) on the reduction of Cu(II) in natural clinoptilolite

    Science.gov (United States)

    Rodríguez Iznaga, I.; Petranovskii, V.; Castillon, F. F.; Farias, M. H.

    2006-10-01

    The [Cu(H 2O) n] 2+ reduction in the presence of Zn 2+, with both cations supported on natural clinoptilolite, has been studied using hydrogen flow at different reduction temperatures. The analysis of the obtained results allows to conclude that the Cu 2+ reduction process and the subsequent aggregation of the reduced species of copper forming particles of colloidal and nanometric size is sensitive to the presence of zinc and to the temperature of reduction. The presence of Zn 2+ diminishes the temperature of Cu 2+ reduction. The Cu 2+ reduction in the presence of Zn 2+ could constitute an alternative procedure to control the degree of aggregation of reduced copper species and, thus, to modify the size of the resultant copper nanoparticles in the clinoptilolite matrix.

  18. A facile green antisolvent approach to Cu2+-doped ZnO nanocrystals with visible-light-responsive photoactivities.

    Science.gov (United States)

    Lu, Yi-Hsuan; Lin, Wei-Hao; Yang, Chao-Yao; Chiu, Yi-Hsuan; Pu, Ying-Chih; Lee, Min-Han; Tseng, Yuan-Chieh; Hsu, Yung-Jung

    2014-08-07

    An environmentally benign antisolvent method has been developed to prepare Cu(2+)-doped ZnO nanocrystals with controllable dopant concentrations. A room temperature ionic liquid, known as a deep eutectic solvent (DES), was used as the solvent to dissolve ZnO powders. Upon the introduction of the ZnO-containing DES into a bad solvent which shows no solvation to ZnO, ZnO was precipitated and grown due to the dramatic decrease of solubility. By adding Cu(2+) ions to the bad solvent, the growth of ZnO from the antisolvent process was accompanied by Cu(2+) introduction, resulting in the formation of Cu(2+)-doped ZnO nanocrystals. The as-prepared Cu(2+)-doped ZnO showed an additional absorption band in the visible range (400-800 nm), which conduced to an improvement in the overall photon harvesting efficiency. Time-resolved photoluminescence spectra, together with the photovoltage information, suggested that the doped Cu(2+) may otherwise trap photoexcited electrons during the charge transfer process, inevitably depressing the photoconversion efficiency. The photoactivity of Cu(2+)-doped ZnO nanocrystals for photoelectrochemical water oxidation was effectively enhanced in the visible region, which achieved the highest at 2.0 at% of Cu(2+). A further increase in the Cu(2+) concentration however led to a decrease in the photocatalytic performance, which was ascribed to the significant carrier trapping caused by the increased states given by excessive Cu(2+). The photocurrent action spectra illustrated that the enhanced photoactivity of the Cu(2+)-doped ZnO nanocrystals was mainly due to the improved visible photon harvesting achieved by Cu(2+) doping. These results may facilitate the use of transition metal ion-doped ZnO in other photoconversion applications, such as ZnO based dye-sensitized solar cells and magnetism-assisted photocatalytic systems.

  19. Characterization and photocatalytic activity of (ZnO–CuO)/SBA-15 nanocomposites synthesized by two-solvent method

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Peng; Zhang, Lili; Zhang, Gongtuo; Li, Guang; Sun, Zhaoqi [Key laboratory of Information Materials and Device, School of Physics and Materials Science, Anhui University, Hefei 230039 (China); Liu, Xiansong [Engineering Technology Research Center of Magnetic Materials, Hefei 230039 (China); Wu, Mingzai, E-mail: mingzaiwu@gmail.com [Key laboratory of Information Materials and Device, School of Physics and Materials Science, Anhui University, Hefei 230039 (China); Engineering Technology Research Center of Magnetic Materials, Hefei 230039 (China)

    2014-08-15

    Schematic between charge genenration and transfer for methylene orange degradation simulated by light. - Highlights: • Two-solvent method is used to prepare ZnO–CuO particles embedded in porous SBA-15. • The absorption edge of (ZnO–CuO)/SBA-15 composite is in the visible light regime. • The absorption intensity of the composite in visible light regime is enhanced. • The (ZnO–CuO)/SBA-15 composite has higher photocatalytic ability than Degussa P-25. - Abstract: Two-solvent method was employed to prepare ZnO–CuO nanoparticles embedded in mesoporous silica SBA-15 ((ZnO–CuO)/SBA-15). The as-obtained (ZnO–CuO)/SBA-15 nanocomposites were characterized by X-ray diffraction, transmission electron microscope, X-ray photoelectron spectroscopy, N{sub 2} adsorption porosimetry, and diffusive reflective UV–vis spectroscopy. The photocatalytic activity of (ZnO–CuO)/SBA-15 nanocomposites toward methylene orange was investigated under simulated solar light irradiation, and the measurement results indicated that (ZnO–CuO)/SBA-15 nanocomposites exhibit higher photodegradation activity toward methylene orange than commercial TiO{sub 2} P-25. The photocatalytic activity of (ZnO–CuO)/SBA-15 nanocomposites were found to be dependent on both the adsorption ability of the nanocomposites and the loading dosage of ZnO–CuO nanoparticles in SBA-15. The optimal loading dosage of ZnO–CuO nanoparticles was determined. Too high or too low loading will lower the photodegradation ability of (ZnO–CuO)/SBA-15 nanocomposites.

  20. Defects related room temperature ferromagnetism in Cu-implanted ZnO nanorod arrays

    Energy Technology Data Exchange (ETDEWEB)

    Li, D. [Department of Physics and Development Center for New Materials Engineering and Technology in Universities of Guangdong, Zhanjiang Normal University, Zhanjiang 524048 (China); Li, D.K. [School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 511400 (China); Wu, H.Z.; Liang, F.; Xie, W. [Department of Physics and Development Center for New Materials Engineering and Technology in Universities of Guangdong, Zhanjiang Normal University, Zhanjiang 524048 (China); Zou, C.W., E-mail: qingyihaiyanas@163.com [Department of Physics and Development Center for New Materials Engineering and Technology in Universities of Guangdong, Zhanjiang Normal University, Zhanjiang 524048 (China); Shao, L.X. [Department of Physics and Development Center for New Materials Engineering and Technology in Universities of Guangdong, Zhanjiang Normal University, Zhanjiang 524048 (China)

    2014-04-05

    Highlights: • Room temperature ferromagnetism was observed in Cu-implanted ZnO nanorod arrays. • Cu-implanted ZnO nanorods show a saturation magnetization value of 1.82 μ{sub B}/Cu. • The origin of ferromagnetism can be explained by the defects related bound magnetic polarons. -- Abstract: Room temperature ferromagnetism (FM) was observed in Cu-implanted ZnO nanorod arrays. The implantation dose for Cu ions was 1 × 10{sup 16} cm{sup −2} and the implantation energy was 100 keV. The ion implantation induced defects and disorder has been observed by the XRD, PL and TEM experiments. The PL spectrum revealed a dominant luminescence peaks at 390 nm and a broad and strong green emission at 500–700 nm, which is considered to be related to the ionized oxygen vacancy. Cu-implanted ZnO nanorods annealed at 500 °C show a saturation magnetization value of 1.82 μ{sub B}/Cu and a positive coercive field of 68 Oe. The carrier concentration is not much improved after annealing and in the order of 10{sup 16} cm{sup −3}, which suggests that FM does not depend upon the presence of a significant carrier concentration. The origin of ferromagnetism behavior can be explained on the basis of electrons and defects that form bound magnetic polarons, which overlap to create a spin-split impurity band.

  1. Substituent Effect on Proton Affinity of Imidazole in Cu,Zn-Superoxide Dismutase

    Institute of Scientific and Technical Information of China (English)

    JI Hong-Fang; ZHANG Hong-Yu

    2006-01-01

    To investigate whether the proton-accepting ability of imidazole in Cu,Zn-superoxide dismutase (SOD) was possibly modulated by Zn(Ⅱ) or not, the proton affinity (Ap) of N3 in imidazole group was calculated by density functional theory (DFF) with B3LYP functional. It was found that Zn(Ⅱ) attenuates the Ap, because of its electron-withdrawing effect, while the three ligands connected with Zn(Ⅱ) (residues of two His and one Asp) exert an opposite effect, owing to their electron-donating ability. This finding suggested that the three ligands should play a role in the normal function of Cu,Zn-SOD and should be taken into consideration in the future study.

  2. Catalytic and photoelectrochemical performances of Cu-Zn-Sn-Se thin films prepared using selenization of electrodeposited Cu-Zn-Sn metal precursors

    Science.gov (United States)

    Shao, Pin-Wen; Li, Chun-Ting; Ho, Kuo-Chuan; Cheng, Kong-Wei

    2015-07-01

    In this study, Cu2ZnSnSe4 (CZTSe) films are deposited onto the fluorine-doped-tin-oxide-coated glass substrate via the selenization of electrodeposited Cu-Zn-Sn metal precursors in an acidic solution with the applied potential of -0.9 V vs. an Ag/AgCl electrode. X-ray diffraction patterns reveal that the samples are the quaternary tetragonal CZTSe phase. The thicknesses and direct band gaps of the samples are in the ranges of 2.3 to 2.7 μm and 0.95 to 1.02 eV, respectively. All samples are p-type semiconductors with carrier density, mobility and flat-band potential in the ranges of 3.88 × 1017 to 1.37 × 1018 cm-3, 10.31 to 12.6 cm2 V-1 s-1 and -0.01 V to -0.08 V vs. Ag/AgCl reference electrode, respectively. The sample with [Cu]/[Zn + Sn] and [Zn]/[Sn] molar ratios of 0.87 and 0.66, respectively, has a maximum photo-enhanced current density of 0.41 mA cm-2 at an applied bias of -0.5 V vs. an Ag/AgCl electrode in 0.5 M H2SO4 solution under illumination. The best photo-conversion efficiency of dye-sensitized solar cells using CZTSe with [Cu]/[Zn + Sn] and [Zn]/[Sn] molar ratios of 0.87 and 0.66, respectively, as the counter electrode was 7.98%. The results show the high quality CZTSe films have potentials in applications of photoelectrochemical water splitting and dye-sensitized solar cells.

  3. Adsorption of multi-heavy metals Zn and Cu onto surficial sediments: modeling and adsorption capacity analysis.

    Science.gov (United States)

    Li, Shanshan; Zhang, Chen; Wang, Meng; Li, Yu

    2014-01-01

    Improved multiple regression adsorption models (IMRAMs) was developed to estimate the adsorption capacity of the components [Fe oxides (Fe), Mn oxides (Mn), organic materials (OMs), residuals] in surficial sediments for multi-heavy metal Zn and Cu. IMRAM is an improved version over MRAM, which introduces a computer program in the model developing process. As MRAM, Zn(Cu) IMRAM, and Cu(Zn) IMRAM again confirmed that there is significant interaction effects that control the adsorption of compounded Zn and Cu, which was neglected by additional adsorption model. The verification experiment shows that the relative deviation of the IMRAMs is less than 13%. It is revealed by the IMRAMs that Mn, which has the greatest adsorption capability for compounded Zn and Cu (54.889 and 161.180 mg/l, respectively), follows by interference adsorption capacity of Fe/Mn (-1.072 and -24.591 mg/l respectively). Zn and Cu influence each other through different mechanisms. When Zn is the adsorbate, compounded Cu mainly affects the adsorption capacities of Fe/Mn and Fe/Mn/OMs; while when Cu is the adsorbate, compounded Zn mainly exerts its effect on Mn, Fe/Mn, and Mn/OMs. It also shows that the compounded Zn or Cu weakened the interference adsorption of Fe/Mn, and meanwhile, strengthened the interference adsorption of Mn/OMs.

  4. Cu{sub 2}ZnSn(S,Se){sub 4} solar cells based on chemical bath deposited precursors

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Chao, E-mail: chao.gao@kit.edu [Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe (Germany); Schnabel, Thomas; Abzieher, Tobias [Zentrum für Sonnenenergie-und Wasserstoff-Forschung Baden-Württemberg (ZSW), 70565 Stuttgart (Germany); Krämmer, Christoph [Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe (Germany); Powalla, Michael [Zentrum für Sonnenenergie-und Wasserstoff-Forschung Baden-Württemberg (ZSW), 70565 Stuttgart (Germany); Light Technology Institute (LTI), Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe (Germany); Kalt, Heinz; Hetterich, Michael [Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe (Germany)

    2014-07-01

    A low-cost method has been developed to fabricate Cu{sub 2}ZnSn(S,Se){sub 4} solar cells. By this method, firstly SnS, CuS, and ZnS layers are successively deposited on a molybdenum/soda lime glass (Mo/SLG) substrate by chemical bath deposition. The Cu{sub 2}ZnSn(S,Se){sub 4} thin films are obtained by annealing the precursor in a selenium atmosphere utilizing a graphite box in the furnace. The obtained Cu{sub 2}ZnSn(S,Se){sub 4} thin films show large crystalline grains. By optimizing the preparation process, Cu{sub 2}ZnSn(S,Se){sub 4} solar cells with efficiencies up to 4.5% are obtained. The results imply that the Cu{sub 2}ZnSn(S,Se){sub 4}/CdS interface and the back contact may be limiting factors for solar cell efficiency. - Highlights: • A chemical bath deposition method is developed to prepare Cu{sub 2}ZnSn(S,Se){sub 4} thin films. • The Cu{sub 2}ZnSn(S,Se){sub 4} thin films show good crystallization. • Solar cells with efficiencies up to 4.5% can be prepared based on the Cu{sub 2}ZnSn(S,Se){sub 4} layer. • The limiting factors for the solar cell efficiency are analyzed.

  5. Visible-light-induced photocatalytic performances of ZnO-CuO nanocomposites for degradation of 2,4-dichlorophenol

    Institute of Scientific and Technical Information of China (English)

    E. D. Sherly; J. Judith Vijaya; L.John Kennedy

    2015-01-01

    Nanostructured ZnO and CuO, and coupled oxides, i.e., ZnCu, Zn2Cu, and ZnCu2, with ZnO:CuO molar ratios of 1:1, 2:1, and 1:2, respectively, were successfully prepared through a simple, one-step, mi-crowave-assisted urea–nitrate combustion synthesis, without the use of organic solvents or surfac-tants. The prepared samples were characterized using X-ray diffraction, X-ray photoelectron spec-troscopy, scanning electron microscopy, energy-dispersive X-ray analysis, transmission electron microscopy, Fourier-transform infrared spectroscopy, diffuse reflectance spectroscopy, and photo-luminescence spectroscopy. The optical absorption of ZnO extended into the visible region after CuO loading. The photocatalytic activities of ZnO, CuO, and the coupled oxides were evaluated based on photodegradation of 2,4-dichlorophenol under visible-light irradiation. The coupled metal oxide Zn2Cu showed the best photocatalytic activity;this was mainly attributed to the extended photore-sponsive range and the increased charge separation rate in the nanocomposite. The photocatalytic degradation process obeyed pseudo-first-order kinetics. The results suggest that the coupled metal oxide Zn2Cu has potential applications as an efficient catalytic material with high efficiency and recyclability for the photocatalytic degradation of organic pollutants in aqueous solution under visible-light irradiation.

  6. Microstructure and properties of hot extruded Mg-3Zn-Y-xCu (x = 0, 1, 3, 5) alloys

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Bao-sheng; Kuang, Ya-fei; Fang, Da-qing; Chai, Yue-sheng [Taiyuan Univ. of Science and Technology (China). College of Materials Science and Engineering; Taiyuan Univ. of Science and Technology (China). Engineering Research Center for Magnesium Alloys of Shanxi Province; Zhang, Yue-zhong [Taiyuan Univ. of Science and Technology (China). Engineering Research Center for Magnesium Alloys of Shanxi Province; Taiyuan Univ. of Science and Technology (China). College of Chemical and Biological Engineering

    2017-04-15

    In petroleum drilling engineering, materials with high strength and rapid degradation are required for degradable fracturing ball applications. In this work, the microstructure, mechanical properties, and corrosion behavior of extruded Mg-3Zn-Y-xCu (x = 0, 1, 3, 5 weight percent) alloys are investigated using optical microscopy, scanning electronic microscopy equipped with energy dispersive X-ray spectroscopy, X-ray diffraction, transmission electronic microscopy, compression tests, electrochemical measurements, and hydrogen evolution tests, to explore their potential as excellent candidate alloys for degradable fracturing ball applications. It is found that the Mg-3Zn-Y alloy is mainly composed of α-Mg, Mg{sub 3}Zn{sub 3}Y{sub 2}, and Mg{sub 3}Zn{sub 6}Y phases. After Cu addition, a new MgZnCu phase is formed, while the Mg{sub 3}Zn{sub 3}Y{sub 2} phase disappears. The Mg-3Zn-Y-3Cu alloy shows the highest compressive strength (473 MPa) and yield strength (402 MPa), mainly attributed to the combined effect of the fine-grain and dispersed precipitation of Mg{sub 3}Zn{sub 6}Y and MgZnCu. The corrosion rate of Mg-3Zn-Y-3Cu reaches 0.41 mm day{sup -1} in 3.5 wt.% KCl solution. Consequently, Mg-3Zn-Y-3Cu alloy is a suitable degradable fracturing ball-seat material.

  7. Comparison of microstructure and corrosion properties of Al-Zn-Mg-Cu alloys 7150 and 7010

    Institute of Scientific and Technical Information of China (English)

    MENG Qing-chang; FAN Xi-gang; REN Shi-yu; ZHANG Xin-mei; ZHANG Bao-you

    2006-01-01

    The influence of coarse Cu-bearing particles, matrix and subgrain boundary precipitates on the stress corrosion susceptibility of the Al-Zn-Mg-Cu alloys was investigated. The strength of 7150 alloy is about 15 MPa higher than that of 7010 alloy.The 7010 alloy exhibits higher resistance to stress corrosion cracking as compared with the 7150 alloy. The coarse Cu-bearing particles are detrimental to the resistance to stress corrosion cracking. The increase of size of matrix and subgrain boundary precipitates decreases the susceptibility of stress corrosion. The anodic dissolution and hydrogen embrittlement govern the cracking process. The severity of stress corrosion cracking is shown to be related to the coarse Cu-bearing particles, matrix and subgrain precipitates in Al-Zn-Mg-Cu alloys.

  8. Electrical Characterization of Cu Composition Effects in CdS/CdTe Thin-Film Solar Cells with a ZnTe:Cu Back Contact: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Li, J. V.; Duenow, J. N.; Kuciauskas, D.; Kanevce, A.; Dhere, R. G.; Young, M. R.; Levi, D. H.

    2012-07-01

    We study the effects of Cu composition on the CdTe/ZnTe:Cu back contact and the bulk CdTe. For the back contact, its potential barrier decreases with Cu concentration while its saturation current density increases. For the bulk CdTe, the hole density increases with Cu concentration. We identify a Cu-related deep level at {approx}0.55 eV whose concentration is significant when the Cu concentration is high. The device performance, which initially increases with Cu concentration then decreases, reflects the interplay between the positive influences and negative influences (increasing deep levels in CdTe) of Cu.

  9. An EXAFS and XANES study of MBE grown Cu-doped ZnO

    CERN Document Server

    Fons, P; Iwata, K; Matsubara, K; Niki, S; Nakahara, K; Takasu, H

    2003-01-01

    The wide bandgap semiconductor, ZnO, is intrinsically n-type and one of the remaining hurdles to be overcome before it can be used for optoelectronic applications is achieving p-type doping. A potential candidate for a p-type dopant is Cu. Towards this end, X-ray near-edge absorption (XANES) has been used to determine changes in valency of Cu in molecular beam epitaxial grown ZnO as a function of growth parameters. Growth parameters varied include the Cu flux which was varied over roughly three orders of magnitude T sub C sub u =800-1000 deg. C and two substrate temperatures: 300 and 600 deg. C. XANES measurements confirmed that Cu was in the +1 valence state for all as-grown samples. Preliminary EXAFS measurements also demonstrated that Cu incorporated into a Zn-atom position substitutionally. X-ray diffraction also indicated significant phase separation with the presence of both metallic Cu and CuO indicated for Cu concentrations >3x10 sup 2 sup 1 cm sup - sup 3.

  10. Adsorption Behavior for CO on Modified MCM-41 with Zn and CuCl

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The Zn-Cu(Ⅰ)/HMCM-41 catalysts were successfully prepared in laboratory scale by solid-state ion exchange with CuCl salt, together with introduction of Zn to improve the dispersion degree of the active component Cu(Ⅰ) on the surface. With increase of the amounts of Zn and CuCl from 0% to 9.0% and 25.0% respectively, CO adsorption the amounts of increased from 10.6 μmol/g to 183.0 μmol/g correspondingly. The in situ FT-IR spectra for CO adsorption demonstrated that there existed two dynamic equilibriums between surface carbonyl complexes: Cu(CO)3+ Cu(CO)2++ CO and Cu(CO)2+ Cu(CO)+ + CO. The equilibriums can be shifted reversibly by changing the temperature and pressure. Due to the modified MCM-41 mesoporous materials possess both of the acidic and metallic carbonyl centers, this kind of material can be developed into mesoporous bifunctional catalysts for carbonylation reactions, in which larger molecules are involved.

  11. Discovery of Cu-Ni-Zn-Sn-Fe intermetallic compounds and S-bearing alloys in the Zhaishang gold deposit, southern Gansu Province and its geological significance

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Examination of ores by optical microscope and EPMA from the Zhaishang gold deposit, southern Gansu Province, has revealed an abundance of rare minerals. These include native metals, Cu-Ni-Zn-Sn-Fe polymetallic compounds and S-bearing alloys of Ni, Fe, Zn, Cu and Sn, occurring as native nickel, Zn-Cu alloy, Ni-Zn-Cu alloy, Sn-Zn-Ni-Cu alloy, Zn-Cu-Ni alloy, Zn-Fe-Cu-Sn-Ni alloy, Fe-Ni-S alloy, Sn-Fe-Ni-S alloy, Fe-Zn-Cu-Ni-S alloy, Zn-Ni-Cu-Fe-S alloy and others. Compared with the Zn-Cu alloy minerals discovered previously, these Zn-Cu minerals fall in the α or α+β portion in Zn-Cu alloy phase diagram, and the α portion has higher Cu content. Cu-Ni-Zn-Sn-Fe intermetallic compounds and S-bearing alloy minerals have not been previously reported in the literature. These rare alloys formed in a strongly reducing environment with absent oxygen and low sulfur activities.

  12. Discovery of Cu-Ni-Zn-Sn-Fe intermetailic compounds and S-bearing alloys in the Zhaishang gold deposit,southern Gansu Province and its geological sisnificance

    Institute of Scientific and Technical Information of China (English)

    LIU JiaJun; MAO GuangJian; MA XingHua; LI LiXing; GUO YuQian; LIU GuangZhi

    2008-01-01

    Examination of ores by optical microscope and EPMA from the Zhaishang gold deposit, southern Gansu Province, has revealed an abundance of rare minerals. These include native metals, Cu-Ni-Zn-Sn-Fe polymetallic compounds and S-bearing alloys of Ni, Fe, Zn, Cu and Sn, occurring as native nickel, Zn-Cu alloy, Ni-Zn-Cu alloy, Sn-Zn-Ni-Cu alloy, Zn-Cu-Ni alloy, Zn-Fe-Cu-Sn-Ni alloy, Fe-Ni-S alloy, Sn-Fe-Ni-S alloy, Fe-Zn-Cu-Ni-S alloy, Zn-Ni-Cu-Fe-S alloy and others. Compared with the Zn-Cu alloy minerals discovered previously, these Zn-Cu minerals fall in the α or α+β portion in Zn-Cu alloy phase diagram, and the α portion has higher Cu content. Cu-Ni-Zn-Sn-Fe intermetallic compounds and S-bearing alloy minerals have not been previously reported in the literature. These rare alloys formed in a strongly reducing environment with absent oxygen and low sulfur activities.

  13. Detection of a ZnSe secondary phase in coevaporated Cu2ZnSnSe4 thin films

    Science.gov (United States)

    Redinger, Alex; Hönes, Katja; Fontané, Xavier; Izquierdo-Roca, Victor; Saucedo, Edgardo; Valle, Nathalie; Pérez-Rodríguez, Alejandro; Siebentritt, Susanne

    2011-03-01

    Cu2ZnSnSe4 (CZTSe) thin films are grown by coevaporation. Composition depth profiles reveal that a Zn rich phase is present at the CZTSe/Mo interface. Raman measurements on the as grown films are used to study the near surface region and the CZTSe/Mo interface, after mechanically removing the thin film from the Mo coated glass. These measurements provide direct experimental evidence of the formation of a ZnSe phase at the CZTSe/Mo interface. While the Raman spectra at the surface region are dominated by CZTSe modes, those measured at the CZTSe/Mo interface are dominated by ZnSe and MoSe2 modes.

  14. Electrical properties of Cu4ZnSnS2/ZnS heterojunction prepared by ultrasonic spray pyrolysis

    Science.gov (United States)

    Guitouni, S.; Khammar, M.; Messaoudi, M.; Attaf, N.; Aida, M. S.

    2016-12-01

    Cu2ZnSnS4 (CZTS)/ZnS heterojunctions have been prepared by a successive deposition of ZnS and CZTS thin films by ultrasonic spray pyrolysis technique on glass substrates. The cupric chloride concentration has been varied in the starting solution in order to investigate its influence on device properties. CZTS/ZnS heterojunctions were characterized by recording their current-voltage characteristics at different temperatures. The obtained results exhibit a good rectifying behavior of the realized heterojunction. Analysis of these results yields saturation current, series resistance and ideality factor determination. From the activation energy of saturation current we inferred that the thermal emission through the barrier height is the dominant mechanism of the reverse current rather than the defects contribution.

  15. Assessment of environmental loads of Cu and Zn from intensive inland shrimp aquaculture.

    Science.gov (United States)

    León-Cañedo, J A; Alarcón-Silvas, S G; Fierro-Sañudo, J F; Mariscal-Lagarda, M M; Díaz-Valdés, T; Páez-Osuna, F

    2017-02-01

    An experiment was developed to simulate inland shrimp farming using diluted seawater (1.9 g L(-1)) containing 75 shrimps (Litopenaeus vannamei) per square meter during a growth cycle of 120 days. In this study, the environmental loads of copper and zinc were estimated and compared to anthropogenic sources and shrimp aquacultures in other locations. Both metals resulted primarily from feeding, which accounted for 91.8% of Cu and 97.0% of Zn. Concentrations of Cu (110.8 ± 11.8 μg g(-1)) and Zn (69.0 ± 0.7 μg g(-1)) measured in the harvested shrimp had higher Cu and lower Zn concentrations compared to those reported for farmed shrimp from Brazil and Mexico. Clearly, organic sludge was the main route of removal for both metals (Cu 46.2%; Zn 92.6%). The annual environmental loads estimated for inland shrimp aquaculture were 598 ± 74 g Cu ha(-1) and 5080 ± 328 g Zn ha(-1).

  16. Salts affect the interaction of ZnO or CuO nanoparticles with wheat.

    Science.gov (United States)

    Stewart, Jacob; Hansen, Trevor; McLean, Joan E; McManus, Paul; Das, Siddhartha; Britt, David W; Anderson, Anne J; Dimkpa, Christian O

    2015-09-01

    Exposure to nanoparticles (NPs) that release metals with potential phytotoxicity could pose problems in agriculture. The authors of the present study used growth in a model growth matrix, sand, to examine the influence of 5 mmol/kg of Na, K, or Ca (added as Cl salts) and root exudates on transformation and changes to the bioactivity of copper(II) oxide (CuO) and zinc oxide (ZnO) NPs on wheat. These salt levels are found in saline agricultural soils. After 14 d of seedling growth, particles with crystallinity typical of CuO or ZnO remained in the aqueous fraction from the sand; particles had negative surface charges that differed with NP type and salt, but salt did not alter particle agglomeration. Reduction in shoot and root elongation and lateral root induction by ZnO NPs were mitigated by all salts. However, whereas Na and K promoted Zn loading into shoots, Ca reduced loading, suggesting that competition with Zn ions for uptake occurred. With CuO NPs, plant growth and loading was modified equally by all salts, consistent with major interaction with the plant with CuO rather than Cu ions. Thus, for both NPs, loading into plant tissues was not solely dependent on ion solubility. These findings indicated that salts in agricultural soils could modify the phytotoxicity of NPs.

  17. Changes of Cu, Zn, and Cd speciation in sewage sludge during composting

    Institute of Scientific and Technical Information of China (English)

    GAO Ding; ZHENG Guo-di; CHEN Tong-bin; LUO Wei; GAO Wei; ZHANG Yi-an; LI Yan-xia

    2005-01-01

    The potential toxicity risks from heavy metals depend on their chemical speciation. The four stages of the Tessier sequential extraction method were employed to investigate changes in heavy metal speciation(Cu, Zn, and Cd) of sewage sludge during forced aeration composting, and then to identify whether the composting process would reduce or enhance their toxicities. Throughout the composting process, the exchangeable, carbonate-bound, Fe-Mn oxide-bound, and organic matter-bound fractions of Cu were converted to the residual Cu fraction. The organic matter-bound Cu fraction greatly contributed to this transformation. Residual Zn fraction was transformed to the Fe-Mn oxide-bound and organic matter-bound fractions after composting. The residual Zn fraction was a major contributor to the organic matter-bound Zn fraction. The availability of Cu and Zn was reduced by composting such that the risk of heavy metal toxicity decreased with prolonged treatment times. Additionally, attention should be paid to the increased availability of Cd in sewage sludge after composting treatment.

  18. Chemical fractionation of Cu and Zn and their impacts on microbial properties in slightly contaminated soils

    Directory of Open Access Journals (Sweden)

    Liu Aiju

    2013-06-01

    Full Text Available Chemical fractionation of Cu and Zn in bulk soil and its effects on soil microbial properties were determined in Cu and Zn contaminated soils (Cu: 35.57~46.37 mg•kg-1, Zn: 74.33~127.20 mg•kg-1 sampled from an agricultural field in outskirts of Zibo, China during the month of September, 2011. A sequential extraction technique (SET was used for metals chemical fractionation analysis in soils and a correlation analysis was applied to determinate the effects of metal on soil microbial properties. Chemical speciation showed that Cu and Zn were mostly present in the residual fraction and their concentrations in the most labile fraction (acid soluble fraction were the lowest in the investigated soils. However, the correlation analysis indicated that the labile forms of Cu/Zn, such as its acid soluble, reducible or oxidizable fractions, were usually significantly negatively correlated with the tested microbial activities at 0.05 or 0.01 probability levels. These results indicate that the metal labile fractions could exert an inhibitory effect on the soil microbial parameters even in the minor contaminated soils.

  19. Effects of high pressure on the microstructure and hardness of a Cu-Zn alloy

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jun; LIU Lin; YANG Jingru; PENG Guirong; LIU Jianhua; ZHANG Ruijun; XING Guangzhong

    2008-01-01

    The microstructure of a Cu-Zn alloy treated under different high pressures was investigated by means of metallographic,scanning electron microscope (SEM),energy dispersive spectrometer (EDS),and X-ray diffraction (XRD),and the hardness of the Cu-Zn alloy was also measured.The results show that the a phase with a smaller grain size,different shapes,and random distribution appears in the Cu-Zn alloy during the solid-state phase transformation generation in the temperature range of 25-750℃ and the pressure range of 0-6 GPa.The amount of residual α phase in the microstructure decreases and then increases with increasing pressure.Under a high pressure of 3 GPa,the least volume fraction of residual α phase was obtained,and under a high pressure of 6 GPa,the changes of the microstructure of the Cu-Zn alloy were not obvious.In addition,high pressure can increase the hardness of the Cu-Zn alloy,but it cannot generate any new phase.

  20. Speciation of Cu and Zn during composting of pig manure amended with rock phosphate.

    Science.gov (United States)

    Lu, Duian; Wang, Lixia; Yan, Baixing; Ou, Yang; Guan, Jiunian; Bian, Yu; Zhang, Yubin

    2014-08-01

    Pig manure usually contains a large amount of metals, especially Cu and Zn, which may limit its land application. Rock phosphate has been shown to be effective for immobilizing toxic metals in toxic metals contaminated soils. The aim of this study work was to investigate the effect of rock phosphate on the speciation of Cu and Zn during co-composting of pig manure with rice straw. The results showed that composting process and rock phosphate addition significantly affected the changes of metal species. During co-composting, the exchangeable and reducible fractions of Cu were transformed to organic and residue fractions, thus the bioavailable Cu fractions were decreased. The rock phosphate addition enhanced the metal transformation depending on the level of rock phosphate amendment. Zinc was found in the exchangeable and reducible fractions in the compost. The bioavailable Zn fraction changed a little during the composting process. The composting process converted the exchangeable Zn fraction into reducible fraction. Addition of an appropriate amount (5.0%) of rock phosphate could advance the conversion. Rock phosphate could reduce metal availability through adsorption and complexation of the metal ions on inorganic components. The increase in pH and organic matter degradation could be responsible for the reduction in exchangeable and bioavailable Cu fractions and exchangeable Zn fraction in rock phosphate amended compost.

  1. Determination of metals (As, Cu, Fe, and Zn in two fish species from the Miankaleh wetland

    Directory of Open Access Journals (Sweden)

    Alipour Hossein

    2016-06-01

    Full Text Available The objective of this study was to determine the concentrations As, Cu, Fe, and Zn in the livers, gills, and muscles of vobla or Caspian roach, Rutilus caspicus (Yakovlev, and bighead goby, Neogobius gorlap (Iljin, from the Miankaleh wetland. The results showed that metal accumulation in the liver tissues was higher than in the gills and muscles for all metals, and Fe concentration was higher than Zn, Cu, and As in all the tissues studied. The concentrations of As, Cu, Fe, and Zn in the livers, gills, and muscles of bighead goby were higher than in vobla tissues, except for concentrations of As in the muscles. Fe, Cu, and Zn concentrations in the muscles were below the maximum permissible limit of the WHO and the FAO for both species, but the concentration of As in the muscles of both species exceeded the permissible limit proposed by the FAO; thus, human consumption should be limited. The levels of the other metals (Fe, Cu and Zn were completely safe.

  2. Structural, magnetic and electrical properties of CuZn ferrite nanopowders

    Science.gov (United States)

    Li, Le-Zhong; Peng, Long; Zhong, Xiao-Xi; Wang, Rui; Tu, Xiao-Qiang

    2016-12-01

    Zn-substituted Cu ferrite nanopowders, Cu1-xZnxFe2O4 (0≤x≤1.0), were synthesized by the sol-gel auto-combustion method. The effect of Zn substitution on the structural, magnetic and electrical properties have been investigated. The DTA and TG results indicate that there are three steps of combustion process. The X-ray diffraction patterns show that there are Fe2O3, CuO and CuFeO2 secondary phases and tetragonal structure when x=0.0. Furthermore, the lattice parameter and the average crystallite size decrease, and the X-ray density increases with the increase of Zn substitution. The saturation magnetization increases with the increase of Zn substitution when x≤0.40, and decreases when x>0.40. Meanwhile, the coercivity monotonically decreases with the increase of Zn substitution. The polarization behavior for all the samples in the test frequency range of 100 Hz to 10 MHz obeys the charge polarization mechanism. Electrical transport behavior of the ferrites nanopowders is same with the impurity semiconductor, and the effect of Zn substitution on the temperature dependence of dc resistivity is observed.

  3. Selective precipitation of Cu from Zn in a pS controlled continuously stirred tank reactor

    Energy Technology Data Exchange (ETDEWEB)

    Sampaio, R.M.M., E-mail: ricardo.sampaio@wur.nl [Sub-department of Environmental Technology, Wageningen University, ' Biotechnion' , Bomenweg 2, P.O. Box 8129, 6700 EV Wageningen (Netherlands); Timmers, R.A., E-mail: ruud.timmers@wur.nl [Sub-department of Environmental Technology, Wageningen University, ' Biotechnion' , Bomenweg 2, P.O. Box 8129, 6700 EV Wageningen (Netherlands); Xu, Y., E-mail: lucyxyzxyz@hotmail.com [Sub-department of Environmental Technology, Wageningen University, ' Biotechnion' , Bomenweg 2, P.O. Box 8129, 6700 EV Wageningen (Netherlands); Keesman, K.J., E-mail: karel.keesman@wur.nl [Systems and Control Group, Wageningen University, Bornsesteeg 59, 6708 PD Wageningen (Netherlands); Lens, P.N.L., E-mail: piet.lens@wur.nl [Sub-department of Environmental Technology, Wageningen University, ' Biotechnion' , Bomenweg 2, P.O. Box 8129, 6700 EV Wageningen (Netherlands)

    2009-06-15

    Copper was continuously and selectively precipitated with Na{sub 2}S to concentrations below 0.3 ppb from water containing around 600 ppm of both Cu and Zn in a Continuously Stirred Tank Reactor. The pH was controlled at 3 and the pS at 25 (pS = -log(S{sup 2-})) by means of an Ag{sub 2}S sulfide selective electrode. Copper's recovery and purity were about 100%, whereas the total soluble sulfide concentration was below 0.02 ppm. X-ray diffraction (XRD) analysis showed that copper precipitated as hexagonal CuS (covellite). The mode of the particle size distribution (PSD) of the CuS precipitates was around 36 {mu}m. The PSD increased by high pS values and by the presence of Zn. Depending on the turbulence, the CuS precipitates can grow up to 200 {mu}m or fragment in particles smaller than 3 {mu}m in a few seconds. Zn precipitation with Na{sub 2}S at pH 3 and 4, in batch, always lead to Zn concentrations above 1 ppm. Zn precipitated as cubic ZnS (spharelite).

  4. Hume-Rothery electron concentration rule across a whole solid solution range in a series of gamma-brasses in Cu-Zn, Cu-Cd, Cu-Al, Cu-Ga, Ni-Zn and Co-Zn alloy systems

    Science.gov (United States)

    Mizutani, U.; Noritake, T.; Ohsuna, T.; Takeuchi, T.

    2010-05-01

    The aim of the present work is to examine if the Hume-Rothery stabilisation mechanism holds across whole solid solution ranges in a series of gamma-brasses with especial attention to the role of vacancies introduced into the large unit cell. The concentration dependence of the number of atoms in the unit cell, N, for gamma-brasses in the Cu-Zn, Cu-Cd, Cu-Al, Cu-Ga, Ni-Zn and Co-Zn alloy systems was determined by measuring the density and lattice constants at room temperature. The number of itinerant electrons in the unit cell, e/uc, is evaluated by taking a product of N and the number of itinerant electrons per atom, e/a, for the transition metal element deduced earlier from the full-potential linearised augmented plane wave (FLAPW)-Fourier analysis. The results are discussed within the rigid-band model using as a host the density of states (DOS) derived earlier from the FLAPW band calculations for the stoichiometric gamma-brasses Cu5Zn8, Cu9Al4 and TM2Zn11 (TM = Co and Ni). A solid solution range of gamma-brasses in Cu-Zn, Cu-Cd, Cu-Al, Cu-Ga and Ni-Zn alloy systems is found to fall inside the existing pseudogap at the Fermi level. This is taken as confirmation of the validity of the Hume-Rothery stability mechanism for a whole solute concentration range of these gamma-brasses. An exception to this behaviour was found in the Co-Zn gamma-brasses, where orbital hybridisation effects are claimed to play a crucial role in stabilisation.

  5. Influence of Solution Heat Treatment on Structure and Mechanical Properties of ZnAl22Cu3 Alloy

    Directory of Open Access Journals (Sweden)

    Michalik R.

    2016-09-01

    Full Text Available The influence of solution heat treatment at 385°C over 10 h with cooling in water on the structure, hardness and strength of the ZnAl22Cu3 eutectoid alloy is presented in the paper. The eutectoid ZnAl22Cu3 alloy is characterized by a dendritic structure. Dendrites are composed of a supersaturated solid solution of Al in Zn. In the interdendritic spaces a eutectoid mixture is present, with an absence of the ε (CuZn4 phase. Solution heat treatment of the ZnAl22Cu3 alloy causes the occurrence of precipitates rich in Zn and Cu, possibly ε phase. Solution heat treatment at 385°C initially causes a significant decrease of the alloy hardness, although longer solution heat treatment causes a significant increase of the hardness as compared to the as-cast alloy.

  6. Ultrasensitive non-enzymatic glucose sensor based on three-dimensional network of ZnO-CuO hierarchical nanocomposites by electrospinning

    OpenAIRE

    2014-01-01

    Three-dimensional (3D) porous ZnO–CuO hierarchical nanocomposites (HNCs) nonenzymatic glucose electrodes with different thicknesses were fabricated by coelectrospinning and compared with 3D mixed ZnO/CuO nanowires (NWs) and pure CuO NWs electrodes. The structural characterization revealed that the ZnO–CuO HNCs were composed of the ZnO and CuO mixed NWs trunk (~200 nm), whose outer surface was attached with small CuO nanoparticles (NPs). Moreover, a good synergetic effect between CuO and ZnO w...

  7. Epitaxial Cu{sub 2}ZnSnSe{sub 4} layers by annealing of Sn/Cu/ZnSe(001) precursors on GaAs(001)

    Energy Technology Data Exchange (ETDEWEB)

    Krämmer, Christoph, E-mail: Christoph.Kraemmer@kit.edu [Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe (Germany); Sachs, Johannes [Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe (Germany); Pfaffmann, Lukas [Laboratory for Electron Microscopy, KIT (Germany); Musiol, Timo; Lang, Mario; Gao, Chao [Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe (Germany); Gerthsen, Dagmar [Laboratory for Electron Microscopy, KIT (Germany); Kalt, Heinz [Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe (Germany); Powalla, Michael [Light Technology Institute, KIT (Germany); Zentrum für Sonnenenergie-und Wasserstoff-Forschung Baden-Württemberg (ZSW), 70565 Stuttgart (Germany); Hetterich, Michael [Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe (Germany)

    2015-05-01

    We report on the fabrication of epitaxial Cu{sub 2}ZnSnSe{sub 4} films by a two-step fabrication approach. An epitaxial ZnSe(001) layer on GaAs(001) is grown by molecular-beam epitaxy followed by sequential deposition of Cu and Sn. The Sn/Cu/ZnSe(001) precursor is then thermally annealed in a selenium atmosphere. Raman spectroscopy confirms the presence of the kesterite phase. Electron microscopy shows that the films exhibit monocrystalline regions of several micrometers in size with inclusions of smaller grains with a different chemical composition. The latter is confirmed by electron backscatter diffraction measurements which prove the conservation of the crystal orientation defined by the cubic ZnSe/GaAs(001) precursor structure throughout the whole CZTSe film. - Highlights: • Two-step fabrication approach to obtain epitaxial kesterite layers is presented. • Kesterite phase formation is confirmed by Raman spectroscopy. • SnSe{sub x} compounds are identified to be the main secondary phase. • Electron backscatter diffraction proves epitaxial orientation of the films.

  8. Surface composition deviation of Cu2ZnSnS4 derivative powdered samples

    Science.gov (United States)

    Harel, S.; Guillot-Deudon, C.; Choubrac, L.; Hamon, J.; Lafond, A.

    2014-06-01

    Powdered samples of Cu2ZnSnS4 derivatives prepared through a solid-state route were investigated by both bulk (electron dispersive X-ray spectroscopy) and surface-sensitive (X-ray photoelectron spectroscopy) methods. We observe a deviation in composition between the surface and the bulk for all non-stoichiometric samples (both Cu-poor and Cu-rich). This behavior has already been observed for slightly Cu-poor CZTS thin films and is reminiscent of that of CIGSe compounds.

  9. Valence band offsets at Cu(In,Ga)Se{sub 2}/Zn(O,S) interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Adler, Tobias; Klein, Andreas [Surface Science Division, Institute of Materials Science, Technische Universitaet Darmstadt, Petersenstrasse 32, 64287, Darmstadt (Germany); Botros, Miriam [Surface Science Division, Institute of Materials Science, Technische Universitaet Darmstadt, Petersenstrasse 32, 64287, Darmstadt (Germany); Zentrum fuer Sonnenenergie- und Wasserstoff-Forschung Baden-Wuerttemberg (ZSW), Industriestrasse 6, 70565, Stuttgart (Germany); Witte, Wolfram; Hariskos, Dimitrios; Menner, Richard; Powalla, Michael [Zentrum fuer Sonnenenergie- und Wasserstoff-Forschung Baden-Wuerttemberg (ZSW), Industriestrasse 6, 70565, Stuttgart (Germany)

    2014-09-15

    The energy band alignment at interfaces between Cu-chalcopyrites and Zn(O,S) buffer layers, which are important for thin-film solar cells, are considered. Valence band offsets derived from X-ray photoelectron spectroscopy for Cu(In,Ga)Se{sub 2} absorber layers with CdS and Zn(O,S) compounds are compared to theoretical predictions. It is shown that the valence band offsets at Cu(In,Ga)Se{sub 2}/Zn(O,S) interfaces approximately follow the theoretical prediction and vary significantly from sample to sample. The integral sulfide content of chemical bath deposited Zn(O,S) is reproducibly found to be 50-70%, fortuitously resulting in a conduction band offset suitable for solar cell applications with Cu(In,Ga)Se{sub 2} absorber materials. The observed variation in offset can neither be explained by variation of the Cu content in the Cu(In,Ga)Se{sub 2} near the interface nor by local variation of the chemical composition. Fermi level pinning induced by high defect concentrations is a possible origin of the variation of band offset. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Engineering of electronic and optical properties of ZnO thin films via Cu doping

    Institute of Scientific and Technical Information of China (English)

    Zhang Guo-Heng; Deng Xiao-Yan; Xue Hua; Xiang Gang

    2013-01-01

    ZnO thin films doped with different Cu concentrations are fabricated by reactive magnetron sputtering technique.XRD analysis indicates that the crystal quality of the ZnO:Cu film can be enhanced by a moderate level of Cu-doping in the sputtering process.The results of XPS spectra of zinc,oxygen,and copper elements show that Cu-doping has an evident and complicated effect on the chemical state of oxygen,but little effect on those of zinc and copper.Interestingly,further investigation of the optical properties of ZnO:Cu samples shows that the transmittance spectra exhibit both red shift and blue shift with the increase of Cu doping,in contrast to the simple monotonic behavior of the Burstein-Moss effect.Analysis reveals that this is due to the competition between oxygen vacancies and intrinsic and surface states of oxygen in the sample.Our result may suggest an effective way of tuning the bandgap of ZnO samples.

  11. Corrosion resistance of benzotriazole passivated Cu-Zn-Al shape memory alloy in artificial Ringer's solution

    Institute of Scientific and Technical Information of China (English)

    LIANG Chenghao; CHEN Bangyi; CHEN Wan; WANG Hua

    2005-01-01

    The corrosion resistance of the Cu-Zn-Al shape memory alloy passivated by benzotriazole was investigated by salt spraying test and electrochemical methods in artificial Ringer's solution. The results showed that after benzotriazole passivation, the corrosion resistance of the Cu-Zn-Al shape memory alloy was improved evidently. The anodic polarization current density of the passivated alloy decreased, the mass loss reduced, the anodic passivation accelerated, the anodic active dissolution was inhibited effectively, and the surface tarnishing was restrained. Infrared reflection spectrum test showed that Cu(Ⅰ)-benzoaiazole or Cu(Ⅱ)-benzotriazole complex layer was formed on the surface of the Cu-Zn-Al shape memory alloy after passivation. This layer appeared plane, well adhesion, and presented homogeneous golden metallic luster. The corrosion resistance of the Cu-Zn-Al shape memory alloy passivated by benzotriazole is improved for the formation of an electrochemical stable baffle layer on passivated surface. This layer separates the metal substrate from the outside corrosion medium effectively and retards the corrosion process of dezincification.

  12. Wetting Behavior and Interfacial Reactions in (Sn-9Zn)-2Cu/Ni Joints during Soldering and Isothermal Aging

    Institute of Scientific and Technical Information of China (English)

    Ning Zhao; Haitao Ma; Haiping Xie; Lai Wang

    2009-01-01

    The wetting property of (Sn-9Zn)-2Cu (wt pct) on Ni substrate and the evolution of interfacial microstructure in (Sn-9Zn)-2Cu/Ni joints during soldering as well as isothermal aging were studied.The wetting ability of eutectic Sn-9Zn solder on Ni substrate was markedly improved by adding 2 wt pct Cu into this solder alloy.Plate-like Cu5Zn8 intermetallic compounds (IMCs) were detected in (Sn-9Zn)-2Cu solder matrix.A continuous Ni5Zn21 IMC layer was formed at (Sn-9Zn)-2Cu/Ni interface after soldering.This IMC layer kept its type and integrality even after aging at 170℃ for up to 1000 h.At the early aging stage (before 500 h), the IMC layer grew fast and its thickness followed a linear relationship with the square root of aging time.Thereafter,however, the thickness increased very slowly with longer aging time.When the joints were aged for 1000 h,a new IMC phase, (Cu,Ni)5Zn8, was found in the matrix near the interface.The formation of (Cu,Ni)5Zn8phase can be attributed to the diffusion of Ni atoms into the solder matrix from the substrate.

  13. Acute toxicity of binary and ternary mixtures of Cd, Cu, and Zn to Daphnia magna.

    Science.gov (United States)

    Meyer, Joseph S; Ranville, James F; Pontasch, Mandee; Gorsuch, Joseph W; Adams, William J

    2015-04-01

    Standard static-exposure acute lethality tests were conducted with Daphnia magna neonates exposed to binary or ternary mixtures of Cd, Cu, and Zn in moderately hard reconstituted water that contained 3 mg dissolved organic carbon/L added as Suwannee River fulvic acid. These experiments were conducted to test for additive toxicity (i.e., the response to the mixture can be predicted by combining the responses obtained in single-metal toxicity tests) or nonadditive toxicity (i.e., the response is less than or greater than additive). Based on total metal concentrations (>90% dissolved) the toxicity of the tested metal mixtures could be categorized into all 3 possible additivity categories: less-than-additive toxicity (e.g., Cd-Zn and Cd-Cu-Zn mixtures and Cd-Cu mixtures when Cu was titrated into Cd-containing waters), additive toxicity (e.g., some Cu-Zn mixtures), or more-than-additive toxicity (some Cu-Zn mixtures and Cd-Cu mixtures when Cd was titrated into Cu-containing waters). Exposing the organisms to a range of sublethal to supralethal concentrations of the titrated metal was especially helpful in identifying nonadditive interactions. Geochemical processes (e.g., metal-metal competition for binding to dissolved organic matter and/or the biotic ligand, and possibly supersaturation of exposure waters with the metals in some high-concentration exposures) can explain much of the observed metal-metal interactions. Therefore, bioavailability models that incorporate those geochemical (and possibly some physiological) processes might be able to predict metal mixture toxicity accurately.

  14. Growth of Cu2ZnSnSe4 thin films by selenization of sputtered single-layered Cu-Zn-Sn metallic precursors from a Cu-Zn-Sn alloy target

    Science.gov (United States)

    Kim, Kyoo-Ho; Amal, Ikhlasul

    2011-09-01

    Cu2ZnSnSe4 (CZTSe) thin films were prepared by the simple process of selenization of single-layered metallic Cu-Zn-Sn precursors. These metallic precursors were deposited by radio frequency magnetron sputtering of a ternary Cu-Zn-Sn alloy target. Successive selenization was performed at various temperatures between 250°C and 500°C for 30 min. X-ray diffraction and Raman analysis showed that a single phase of the CZTSe compound can be obtained by selenization at 400°C, while increasing the selenization temperature to 500°C improves the grain size and crystal quality. The direct optical band gap of CZTSe films was calculated to be 1.06 eV to 1.09 eV with a high absorption coefficient on the order of 104 cm-1 for samples selenized at 400°C to 500°C. The obtained films are p-type semiconductors with bulk carrier concentrations of 2.41 to 7.96 × 1018 cm3, mobilities of 1.30 cm2 V-1 s-1 to 9.27 cm2 V-1 s-1, and resistivities of 0.20 Ωcm to 1.95 Ωcm.

  15. A role for Haemophilus ducreyi Cu,ZnSOD in resistance to heme toxicity.

    Science.gov (United States)

    Negari, Shahin; Sulpher, Jeff; Pacello, Francesca; Ingrey, Keely; Battistoni, Andrea; Lee, B Craig

    2008-06-01

    The Cu,Zn superoxide dismutase (Cu,ZnSOD) from Haemophilus ducreyi is the only enzyme of this class which binds a heme molecule at its dimer interface. To explore the role of the enzyme in this heme-obligate bacterium, a sodC mutant was created by insertional inactivation. No difference in growth rate was observed during heme limitation. In contrast, under heme rich conditions growth of the sodC mutant was impaired compared to the wild type strain. This growth defect was abolished by supplementation of exogenous catalase. Genetic complementation of the sodC mutant in trans demonstrated that the enzymatic property or the heme-binding activity of the protein could repair the growth defect of the sodC mutant. These results indicate that Cu,ZnSOD protects Haemophilus ducreyi from heme toxicity.

  16. Article Expression, Purification, and Characterization of Cu/ZnSOD from Panax Ginseng

    Directory of Open Access Journals (Sweden)

    Dayong Ding

    2014-06-01

    Full Text Available Superoxide dismutase (SOD has a strong antioxidant effect, but the traditional SOD extraction method is not the most efficient method of SOD amplification. In this study, we report the cloning of the Cu/ZnSOD gene from Panax ginseng into a temperature-regulated expression plasmid, pBV220. Cu/ZnSOD inclusion bodies were expressed in E. coli at a high level. Then, the inclusion bodies were purified by ion-exchange chromatography and molecular sieve chromatography. Finally, we obtained stable SOD in the bacterial broth, with a protein content of 965 mg/L and enzyme specific activity of 9389.96 U/mg. These results provide a foundation for future studies on the antioxidant mechanisms of ginseng and the development and application of ginseng Cu/ZnSOD.

  17. Epitaxial growth of magnetic ZnCuO thin films by pulsed laser deposition

    Science.gov (United States)

    Kim, Dong Hun; Kim, Tae Cheol; Lee, Seung Han; Jung, Hyun Kyu; Jeong, Jaeeun; Han, Seung Ho

    2017-02-01

    The crystal structure and magnetic properties of epitaxial ZnO thin films doped with 5 at% Cu on SrTiO3 (001) and (111) substrates were investigated. In the case of films deposited in oxygen, unique crystallographic growth directions on different substrates were observed, while a metallic phase was detected in films grown under vacuum. The Cu-doped ZnO thin films deposited on the SrTiO3 (111) substrates, with hexagonal structures, showed a single epitaxial relationship with the substrates, whereas those deposited on the SrTiO3 (001) substrates showed a double epitaxial growth mode. The epitaxial ZnCuO thin films deposited on the SrTiO3 (111) substrates under high vacuum exhibited a ferromagnetic signal at room temperature.

  18. The band gap of Cu2ZnSnSe4: Effect of order-disorder

    Science.gov (United States)

    Rey, G.; Redinger, A.; Sendler, J.; Weiss, T. P.; Thevenin, M.; Guennou, M.; El Adib, B.; Siebentritt, S.

    2014-09-01

    The order-disorder transition in kesterite Cu2ZnSnSe4 (CZTSe), an interesting material for solar cell, has been investigated by spectrophotometry, photoluminescence (PL), and Raman spectroscopy. Like Cu2ZnSnS4, CZTSe is prone to disorder by Cu-Zn exchanges depending on temperature. Absorption measurements have been used to monitor the changes in band gap energy (Eg) of solar cell grade thin films as a function of the annealing temperature. We show that ordering can increase Eg by 110 meV as compared to fully disordered material. Kinetics simulations show that Eg can be used as an order parameter and the critical temperature for the CZTSe order-disorder transition is 200 ± 20 °C. On the one hand, ordering was found to increase the correlation length of the crystal. But on the other hand, except the change in Eg, ordering did not influence the PL signal of the CZTSe.

  19. Electrical and gas sensing investigations on the sprayed ZnO:Cu thin films

    Science.gov (United States)

    Mhamdi, A.; Alkhalifah, Menea S.; Rajeh, S.; Labidi, A.; Amlouk, M.; Belgacem, S.

    2017-09-01

    The electrical and gas sensing properties of the sprayed Cu doped ZnO thin layers were investigated. The main study is an analysis of the conduction mechanism based on the measurement results of the frequency dispersion of the conductivity at different temperatures performed by impedance spectroscopy. It emerges from this study that the transport mechanism of charge carriers in such thin films is a thermally activated hopping mechanism. This process is confirmed by the obtained values of the maximum barrier height Wm deduced from the study of the frequency power law of the ac conductivity. Otherwise, we have studied the response evolution of ZnO: Cu sensors ethanol versus time, working temperature and relative doping. From the measurement results of gas sensing properties of ZnO:Cu thin film, we find that a good stability and response was observed for a doping of 2%.

  20. Effect of Sn on the Color and Tarnishing of Cu-Mn-Zn Alloys

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The effect of Sn on the color and tarnishing of Cu-Mn-Zn alloys is investigated quantitatively. Using the CIE LAB color system,color parameters such as L*, a* and b* are selected to describe the surface color of alloys while the color difference (△E*)is used to evaluate the color stability. The results show that with the increase of Sn, the color change of Cu-Mn-Zn alloys is greatly reduced and the corrosion resistance in the synthetic sweat is improved dramatically. However, up to 4.4 wt pct Sn does not change the color of Cu-Mn-Zn alloys much. XPS and AES are employed to analyze the tarnished surface. It is proved that a Sn enriched film is formed and Sn takes the form of Sn oxide. This thin and protective oxide film can prevent alloy from further tarnishing.

  1. Novel inhibitors to Taenia solium Cu/Zn superoxide dismutase identified by virtual screening

    Science.gov (United States)

    García-Gutiérrez, P.; Landa-Piedra, A.; Rodríguez-Romero, A.; Parra-Unda, R.; Rojo-Domínguez, A.

    2011-12-01

    We describe in this work a successful virtual screening and experimental testing aimed to the identification of novel inhibitors of superoxide dismutase of the worm Taenia solium ( TsCu/Zn-SOD), a human parasite. Conformers from LeadQuest® database of drug-like compounds were selected and then docked on the surface of TsCu/Zn-SOD. Results were screened looking for ligand contacts with receptor side-chains not conserved in the human homologue, with a subsequent development of a score optimization by a set of energy minimization steps, aimed to identify lead compounds for in vitro experiments. Six out of fifty experimentally tested compounds showed μM inhibitory activity toward TsCu/Zn-SOD. Two of them showed species selectivity since did not inhibit the homologous human enzyme when assayed in vitro.

  2. Cumulation of Cu, Zn, Cd, and Mn in Plants of Gardno Lake

    Directory of Open Access Journals (Sweden)

    Trojanowski J.

    2013-04-01

    Full Text Available In the present paper there have been shown the results of research on yhe content of Zn, Cd, Cu, Mn and Pb in chosen plants of Lake Gardno.The biggest concentration of those metals has been observed in Potamogton natans and Elodea canadensis, on average Zn – 34.9, Pb -2.77, Cd – 0.62, Cu – 3.24 and Mn – 257.4 μg g-1. It has been found that the over-ground parts of the plants under analysis cumulate several times less of heavy metals than their roots. The determined enrichment factors enabled the researchers to state that Cu in the examined plants is of natural origin while Mn, Cd and Zn – of anthropogenic origin.

  3. Magneto-viscosity of hydrothermal synthesized Cu-Zn ferrite ferrofluids

    Directory of Open Access Journals (Sweden)

    Nisha Gautam

    2017-05-01

    Full Text Available The paraffin based ferrofluids were synthesized using the oleic acid coated Cu-Zn ferrite (CZF nanoparticles of compositions Cu0.6Zn0.4Fe2O4 (CZF1 and Cu0.4Zn0.6Fe2O4 (CZF2 synthesized by hydrothermal process. The transmission electron micrographs (TEM show the cubic shape particles of 4 to 10 nm and 4 to 18 nm size for CZF1 and CZF2 respectively. The nanoparticles show superparamagnetic behaviour. The viscosity increases with increase in magnetic field due to the formation of long chains of magnetic nanoparticles in ferrofluid. At higher flow rate, the magnetic chains break into smaller units and arrange along the flow direction. The flow curves show power law behavior. The size of magnetic nanoparticles influences the magneto-viscosity of the ferrofluids.

  4. Magneto-viscosity of hydrothermal synthesized Cu-Zn ferrite ferrofluids

    Science.gov (United States)

    Gautam, Nisha; Thirupathi, Gadipelly; Singh, Rajender

    2017-05-01

    The paraffin based ferrofluids were synthesized using the oleic acid coated Cu-Zn ferrite (CZF) nanoparticles of compositions Cu0.6Zn0.4Fe2O4 (CZF1) and Cu0.4Zn0.6Fe2O4 (CZF2) synthesized by hydrothermal process. The transmission electron micrographs (TEM) show the cubic shape particles of 4 to 10 nm and 4 to 18 nm size for CZF1 and CZF2 respectively. The nanoparticles show superparamagnetic behaviour. The viscosity increases with increase in magnetic field due to the formation of long chains of magnetic nanoparticles in ferrofluid. At higher flow rate, the magnetic chains break into smaller units and arrange along the flow direction. The flow curves show power law behavior. The size of magnetic nanoparticles influences the magneto-viscosity of the ferrofluids.

  5. Directed Evolution of Human Cu,Zn-SOD Under Artificial Oxidant Pressures

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Cu,Zn-SOD is a highly conserved enzyme and the controversy about its evolutionary possibility in the near future has been lively. In order to further our understanding of the future fate of human Cu,Zn-SOD, we adopted a strategy relating to the directed evolution to study how the mutants of human Cu,Zn-SOD respond to different oxidative stress. After five rounds of screening, we found a mutant that can survive under harsh pressures and DNA sequencing proves that it shows a mutation responsible for the phenomenon. However, under natural pressure, our screening comes to nothing. Then we may draw the following conclusions: the evolution of biological macromolecules in some respect depends on their surroundings and if they are too familiar with a certain environment, they may embody evolutionary inertia.

  6. Recrystallization of the cold-deformed discontinuous precipitation microstructure in Al-Zn (-Cu) alloys

    Institute of Scientific and Technical Information of China (English)

    DING Hua; REN Yuping; HAO Shiming; WANG Dapeng; ZHAO Gang

    2004-01-01

    Recrystallization of cold-rolled discontinuous precipitation microstructure which has fine laminar structure in an Al-40% Zn (atom fraction) binary alloy is investigated by optical microscopy, SEM and TEM. It is found that there are two kinds of recrystallization mechanisms: continuous coarsening (CC) and discontinuous coarsening (DC). The latter can be divided into coarsening mainly driven by stored deformation energy at colony boundaries and slip bands and the one mainly driven by boundary energy in the area with little deformation. It is shown that the addition of Cu can retard the nucleation of coarsening cells and their growth. X-Ray diffraction analysis indicated the metastable phase CuZn4 transformed into equilibrium phase Al4Cu3Zn during the heating process.

  7. Effect of impurity concentration on optical and magnetic properties in ZnS:Cu nanoparticles

    Science.gov (United States)

    Chandra Patel, Prayas; Ghosh, Surajit; Srivastava, P. C.

    2017-09-01

    To obtain enhanced room temperature ferromagnetism (RTFM) along with the increase in optical bandgap in the compound semiconductors has been an interesting topic. Here, we report RTFM along with increase in energy bandgap in chemically synthesized Zn1-xCuxS (0 ≤ x ≤ 0.04) DMS nanoparticles. Structural properties of the synthesized samples studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) show the formation of cubic phase Cu doped ZnS nanoparticles of 3-5 nm size. An intrinsic weak ferromagnetic behavior was observed in pure ZnS sample (at 300 K) which got increased in Cu doped samples and was understood due to defect induced ferromagnetism. UV-vis measurement showed increase in the energy bandgap with the increase in Cu doping. The PL study suggested the presence of sulfur and zinc vacancies and surface defects which were understood contributing to the intrinsic FM behavior.

  8. Cu and Zn uptake by Halimione portulacoides (L. ) Aellen. A long-term accumulation experiment

    Energy Technology Data Exchange (ETDEWEB)

    Reboredo, F. (New Univ. of Lisbon (Portugal))

    1991-03-01

    Coastal areas and plant species colonizing salt-marshes are often exposed to a large diversity of pollutants, with emphasis on heavy metals. The important role of marsh vegetation in the accumulation of metals has been shown. Halimione portulacoides is one of the most representative halophytes of the salt-marshes of the river Sado estuary. In order to study the uptake and pattern of accumulation of Cu and Zn by the roots, stems and leaves of Halimione, plants were cultivated in vitro and treated daily with solutions containing 5, 25 and 50ppm Cu (as CuCl{sub 2}) and 50, 100 and 150ppm Zn (as ZnCl{sub 2}).

  9. Behavior and influence of Pb and Bi in Ag-Cu-Zn brazing alloy

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The effects of trace content of Pb and Bi elements on the spreading property and the strength of brazed joints of Ag-Cu-Zn filler metal have been studied. The results show that Pb has little effect on both above properties, and Bi has remarkable influence on the spreading property but little effect on the strength of brazed joint. Pb and Bi dissolve into the Ag-Cu-Zn matrix and will melt and gather at lower temperature when that alloy is being heated. Therefore a liquid forms on the surface of the Ag-Cu-Zn alloy and overlays the melting alloy, then keeps the filler metal away from the materials being joined, and so decreases the spreading property.

  10. Passivation for Cu2ZnSnS4/WZ-ZnO interface states: From the first principles calculations

    Science.gov (United States)

    Cheng, Yu-Wen; Tang, Fu-Ling; Xue, Hong-Tao; Liu, Hong-Xia; Gao, Bo

    2017-02-01

    We employed the first-principles calculations to investigate F, Cl and H's passivation effects for Cu2ZnSnS4 (102)/WZ-ZnO (110) interface, in which the interface states mainly originate from Sn atoms. The interface states peaks can be reduced more or less by introducing F, Cl and H around Sn atom. H and F have a more efficient passivation effect than Cl atoms. The charge density difference and Bader atomic charge analysis suggests that F, Cl and H can get part of the electrons leading to interface states and that the interface states can be passivated by F, Cl or H atoms.

  11. Chemical behavior of Cu, Zn, Cd, and Pb in a eutrophic reservoir: speciation and complexation capacity.

    Science.gov (United States)

    Tonietto, Alessandra Emanuele; Lombardi, Ana Teresa; Choueri, Rodrigo Brasil; Vieira, Armando Augusto Henriques

    2015-10-01

    This research aimed at evaluating cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn) speciation in water samples as well as determining water quality parameters (alkalinity, chlorophyll a, chloride, conductivity, dissolved organic carbon, dissolved oxygen, inorganic carbon, nitrate, pH, total suspended solids, and water temperature) in a eutrophic reservoir. This was performed through calculation of free metal ions using the chemical equilibrium software MINEQL+ 4.61, determination of labile, dissolved, and total metal concentrations via differential pulse anodic stripping voltammetry, and determination of complexed metal by the difference between the total concentration of dissolved and labile metal. Additionally, ligand complexation capacities (CC), such as the strength of the association of metals-ligands (logK'ML) and ligand concentrations (C L) were calculated via Ruzic's linearization method. Water samples were taken in winter and summer, and the results showed that for total and dissolved metals, Zn > Cu > Pb > Cd concentration. In general, higher concentrations of Cu and Zn remained complexed with the dissolved fraction, while Pb was mostly complexed with particulate materials. Chemical equilibrium modeling (MINEQL+) showed that Zn(2+) and Cd(2+) dominated the labile species, while Cu and Pb were complexed with carbonates. Zinc was a unique metal for which a direct relation between dissolved species with labile and complexed forms was obtained. The CC for ligands indicated a higher C L for Cu, followed by Pb, Zn, and Cd in decreasing amounts. Nevertheless, the strength of the association of all metals and their respective ligands was similar. Factor analysis with principal component analysis as the extraction procedure confirmed seasonal effects on water quality parameters and metal speciation. Total, dissolved, and complexed Cu and total, dissolved, complexed, and labile Pb species were all higher in winter, whereas in summer, Zn was mostly present in the

  12. Immobilization of Zn, Cu, and Pb in contaminated soils using phosphate rock and phosphoric acid

    Energy Technology Data Exchange (ETDEWEB)

    Cao Xinde [School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)] [Soil and Water Science Department, University of Florida, Gainesville, FL 32611 (United States); Wahbi, Ammar [Soil Science Department, Faculty of Agriculture, University of Aleppo, Aleppo (Syrian Arab Republic); Ma, Lena, E-mail: lqma@ufl.edu [Soil and Water Science Department, University of Florida, Gainesville, FL 32611 (United States); Li Bing; Yang Yongliang [National Research Center for Geoanalysis, Beijing 100037 (China)

    2009-05-30

    Considerable research has been done on P-induced Pb immobilization in Pb-contaminated soils. However, application of P to soils contaminated with multiple heavy metals is limited. The present study examined effectiveness of phosphoric acid (PA) and/or phosphate rock (PR) in immobilizing Pb, Cu, and Zn in two contaminated soils. The effectiveness was evaluated using water extraction, plant uptake, and a simple bioaccessibility extraction test (SBET) mimicking metal uptake in the acidic environment of human stomach. The possible mechanisms for metal immobilization were elucidated using X-ray diffraction, scanning electron microscopy, and chemical speciation program Visual MINTEQ. Compared to the control, all P amendments significantly reduced Pb water solubility, phytoavailability, and bioaccessibility by 72-100%, 15-86%, and 28-92%, respectively. The Pb immobilization was probably attributed to the formation of insoluble Pb phosphate minerals. Phosphorus significantly reduced Cu and Zn water solubility by 31-80% and 40-69%, respectively, presumably due to their sorption on minerals (e.g., calcite and phosphate phases) following CaO addition. However, P had little effect on the Cu and Zn phytoavailability; while the acid extractability of Cu and Zn induced by SBET (pH 2) were even elevated by up to 48% and 40%, respectively, in the H{sub 3}PO{sub 4} treatments (PA and PR + PA). Our results indicate that phosphate was effective in reducing Pb availability in terms of water solubility, bioaccessibility, and phytoavailability. Caution should be exercised when H{sub 3}PO{sub 4} was amended to the soil co-contaminated with Cu and Zn since the acidic condition of SBET increased Cu and Zn bioaccessibility though their water solubility was reduced.

  13. Immobilization of Zn, Cu, and Pb in contaminated soils using phosphate rock and phosphoric acid.

    Science.gov (United States)

    Cao, Xinde; Wahbi, Ammar; Ma, Lena; Li, Bing; Yang, Yongliang

    2009-05-30

    Considerable research has been done on P-induced Pb immobilization in Pb-contaminated soils. However, application of P to soils contaminated with multiple heavy metals is limited. The present study examined effectiveness of phosphoric acid (PA) and/or phosphate rock (PR) in immobilizing Pb, Cu, and Zn in two contaminated soils. The effectiveness was evaluated using water extraction, plant uptake, and a simple bioaccessibility extraction test (SBET) mimicking metal uptake in the acidic environment of human stomach. The possible mechanisms for metal immobilization were elucidated using X-ray diffraction, scanning electron microscopy, and chemical speciation program Visual MINTEQ. Compared to the control, all P amendments significantly reduced Pb water solubility, phytoavailability, and bioaccessibility by 72-100%, 15-86%, and 28-92%, respectively. The Pb immobilization was probably attributed to the formation of insoluble Pb phosphate minerals. Phosphorus significantly reduced Cu and Zn water solubility by 31-80% and 40-69%, respectively, presumably due to their sorption on minerals (e.g., calcite and phosphate phases) following CaO addition. However, P had little effect on the Cu and Zn phytoavailability; while the acid extractability of Cu and Zn induced by SBET (pH 2) were even elevated by up to 48% and 40%, respectively, in the H(3)PO(4) treatments (PA and PR+PA). Our results indicate that phosphate was effective in reducing Pb availability in terms of water solubility, bioaccessibility, and phytoavailability. Caution should be exercised when H(3)PO(4) was amended to the soil co-contaminated with Cu and Zn since the acidic condition of SBET increased Cu and Zn bioaccessibility though their water solubility was reduced.

  14. Biosolids conditioning and the availability of Cu and Zn for rice

    Directory of Open Access Journals (Sweden)

    Pires Adriana Marlene Moreno

    2003-01-01

    Full Text Available Sewage treatment process is a factor to be considered for biosolid use in agriculture. The greatest sewage treatment facility of São Paulo State (Barueri/SP altered in the year 2000 of its sludge treatment. The addition of ferric chloride and calcium oxide was substituted by the addition of polymers. This change can modify heavy metal phytoavailability. A green house experiment, using 2 soils treated with biosolids (three with and one without polymers with and without polymers was performed to evaluate Cu and Zn phytoavailability using rice (Oryza sativa L. as test plant. Three kilograms of two soils (Haphorthox abd Hapludox were placed in pots and the equivalent to 50 Mg ha-1 (dry basis of biosolid was added and incorporated. The statistical design adopted was completely randomized experiment, with five treatments (control plus four different biossolids each soil and four replications. Soil pH before and after harvesting, Cu and Zn concentrations in shoot were evaluated. Tukey (5% was used to compare the results. DTPA, HCl 0.1 mol L-1 and Mehlich 3 were used to estimate soil available Cu and Zn. Amounts extracted were correlated to those presented in rice shoot, to evaluate the efficiency of predicting Cu and Zn phytoavailabilities. Biosolids with polymers presented higher Cu and Zn phytoavailabilities, possibly due to the lower pH of these residues. In this case soil presented lowest values of pH and plant shoot had highest. All extractants were representative of Cu and Zn availability to rice plants.

  15. Biocompatibility Assessment of Novel Bioresorbable Alloys Mg-Zn-Se and Mg-Zn-Cu for Endovascular Applications: In- Vitro Studies

    OpenAIRE

    Persaud-Sharma, Dharam; Budiansky, Noah; McGoron, Anthony J

    2013-01-01

    Previous studies have shown that using biodegradable magnesium alloys such as Mg-Zn and Mg-Zn-Al possess the appropriate mechanical properties and biocompatibility to serve in a multitude of biological applications ranging from endovascular to orthopedic and fixation devices. The objective of this study was to evaluate the biocompatibility of novel as-cast magnesium alloys Mg-1Zn-1Cu wt.% and Mg-1Zn-1Se wt.% as potential implantable biomedical materials, and compare their biologically effecti...

  16. Synthesis, characterization and phosphotriesterase mimetic activity of some Zn(II) and Cu(II) complexes

    Indian Academy of Sciences (India)

    Mamata Singh; Ray J Butcher; Jerry P Jasinski; James A Golen; Govindasamy Mugesh

    2012-11-01

    We report here the synthesis and characterization of a few phenolate-based ligands bearing tertamino substituent and their Zn(II) and Cu(II) metal complexes. Three mono/binuclear Zn(II) and Cu(II) complexes [Zn(L1)(H2O)].CH3OH.H2O (1) (H2 L1 = 6,6′-(((2-dimethylamino)ethylazanediyl)bis(methylene))bis(2, 4-dimethylphenol), [Zn2(L2)2] (2) (H2L2 = 2,2′-(((2-dimethylamino)ethyl)azanediyl)bis(methylene)bis(4-methylphenol) and [Cu2(L3)2.CH2 Cl2] (3) (H2L3 = (6,6′-(((2-(diethylamino)ethyl)azanediyl)bis(methylene)) bis(methylene))bis(2,4-dimethylphenol) were synthesized by using three symmetrical tetradendate ligands containing N2O2 donor sites. These complexes are characterized by a variety of techniques including; elemental analysis, mass spectrometry, 1H, 13C NMR spectroscopic and single crystal X-ray analysis. The new complexes have been tested for the phosphotriesterase (PTE) activity with the help of 31P NMR spectroscopy. The 31P NMR studies show that mononuclear complex [Zn(L1)(H2O)].CH3OH.H2O (1) can hydrolyse the phosphotriester i.e., p-nitrophenyl diphenylphosphate (PNPDPP), more efficiently than the binuclear complexes [Zn2(L2)2] (2) and [Cu2(L3)2.CH2Cl2] (3). The mononuclear Zn(II) complex (1) having one coordinated water molecule exhibits significant PTE activity which may be due to the generation of a Zn(II)-bound hydroxide ion during the hydrolysis reactions in CHES buffer at pH 9.0.

  17. Cation/Anion Substitution in Cu2ZnSnS4 for Improved Photovoltaic Performance

    Science.gov (United States)

    Ananthoju, Balakrishna; Mohapatra, Jeotikanta; Jangid, Manoj K.; Bahadur, D.; Medhekar, N. V.; Aslam, M.

    2016-10-01

    Cations and anions are replaced with Fe, Mn, and Se in CZTS in order to control the formations of the secondary phase, the band gap, and the micro structure of Cu2ZnSnS4. We demonstrate a simplified synthesis strategy for a range of quaternary chalcogenide nanoparticles such as Cu2ZnSnS4 (CZTS), Cu2FeSnS4 (CFTS), Cu2MnSnS4 (CMTS), Cu2ZnSnSe4 (CZTSe), and Cu2ZnSn(S0.5Se0.5)4 (CZTSSe) by thermolysis of metal chloride precursors using long chain amine molecules. It is observed that the crystal structure, band gap and micro structure of the CZTS thin films are affected by the substitution of anion/cations. Moreover, secondary phases are not observed and grain sizes are enhanced significantly with selenium doping (grain size ~1 μm). The earth-abundant Cu2MSnS4/Se4 (M = Zn, Mn and Fe) nanoparticles have band gaps in the range of 1.04–1.51 eV with high optical-absorption coefficients (~104 cm‑1) in the visible region. The power conversion efficiency of a CZTS solar cell is enhanced significantly, from 0.4% to 7.4% with selenium doping, within an active area of 1.1 ± 0.1 cm2. The observed changes in the device performance parameters might be ascribed to the variation of optical band gap and microstructure of the thin films. The performance of the device is at par with sputtered fabricated films, at similar scales.

  18. Structural and optoelectronic properties of glucose capped Al and Cu doped ZnO nanostructures

    Directory of Open Access Journals (Sweden)

    Patwari Gunjan

    2016-03-01

    Full Text Available Al and Cu doped ZnO nanoparticles are considered as appropriate for modulation of structural and optoelectronic properties. Al atoms are found to substitute the host Zn whereas Cu dopants mainly segregate in grain boundaries and thereby determine the optical properties. The undoped as well as Al and Cu doped ZnO exhibit spherical well defined particles. The spherical nanoparticles change to rod type structures on co-doping. The average particle size decreases on doping what consequently results in an increment in band gap. Blue shift in UV absorption is governed by the functional group of glucose; further blue shift occurring on metal doping may be attributed to Burstein-Moss effect. PL spectra of doped and undoped ZnO show a dominant near band gap UV emission along with visible emission owing to the defects. The PL peak intensity increases on doping with Cu and Al. The linear I-V characteristics indicate the ohmic behavior of ZnO nanostructures.

  19. Structural, electronic and optical properties of Cu-doped ZnO: experimental and theoretical investigation

    Science.gov (United States)

    Horzum, S.; Torun, E.; Serin, T.; Peeters, F. M.

    2016-06-01

    Experiments are supplemented with ab initio density functional theory (DFT) calculations in order to investigate how the structural, electronic and optical properties of zinc oxide (ZnO) thin films are modified upon Cu doping. Changes in characteristic properties of doped thin films, that are deposited on a glass substrate by sol-gel dip coating technique, are monitored using X-ray diffraction (XRD) and UV measurements. Our ab initio calculations show that the electronic structure of ZnO can be well described by DFT+U/? method and we find that Cu atom substitutional doping in ZnO is the most favourable case. Our XRD measurements reveal that the crystallite size of the films decrease with increasing Cu doping. Moreover, we determine the optical constants such as refractive index, extinction coefficient, optical dielectric function and optical energy band gap values of the films by means of UV-Vis transmittance spectra. The optical band gap of ZnO the thin film linearly decreases from 3.25 to 3.20 eV at 5% doping. In addition, our calculations reveal that the electronic defect states that stem from Cu atoms are not optically active and the optical band gap is determined by the ZnO band edges. Experimentally observed structural and optical results are in good agreement with our theoretical results.

  20. Investigations on structural, vibrational and dielectric properties of nanosized Cu doped Mg-Zn ferrites

    Science.gov (United States)

    Yadav, Anand; Rajpoot, Rambabu; Dar, M. A.; Varshney, Dinesh

    2016-05-01

    Transition metal Cu2+ doped Mg-Zn ferrite [Mg0.5Zn0.5-xCuxFe2O4 (0.0 ≤ x ≤ 0.5)] were prepared by sol gel auto combustion (SGAC) method to probe the structural, vibrational and electrical properties. X-ray diffraction (XRD) pattern reveals a single-phase cubic spinel structure without the presence of any secondary phase corresponding to other structure. The average particle size of the parent Mg0.5Zn0.5Fe2O4 is found to be ~29.8 nm and is found to increase with Cu2+ doping. Progressive reduction in lattice parameter of Mg0.5Zn0.5Fe2O4 has been observed due to difference in ionic radii of cations with improved Cu doping. Spinel cubic structure is further confirmed by Raman spectroscopy. Small shift in Raman modes towards higher wave number has been observed in doped Mg-Zn ferrites. The permittivity and dielectric loss decreases at lower doping and increases at higher order doping of Cu2+.

  1. Leaching potential of pervious concrete and immobilization of Cu, Pb and Zn using pervious concrete.

    Science.gov (United States)

    Solpuker, U; Sheets, J; Kim, Y; Schwartz, F W

    2014-06-01

    This paper investigates the leaching potential of pervious concrete and its capacity for immobilizing Cu, Pb and Zn, which are common contaminants in urban runoff. Batch experiments showed that the leachability of Cu, Pb and Zn increased when pHconcrete might function to attenuate contaminant migration. A porous concrete block was sprayed with low pH water (pH=4.3±0.1) for 190 h. The effluent was highly alkaline (pH~10 to 12). In the first 50 h, specific conductance and trace-metal were high but declined towards steady state values. PHREEQC modeling showed that mixing of interstitial alkaline matrix waters with capillary pore water was required in order to produce the observed water chemistry. The interstitial pore solutions seem responsible for the high pH values and relatively high concentrations of trace metals and major cations in the early stages of the experiment. Finally, pervious concrete was sprayed with a synthetic contaminated urban runoff (10 ppb Cu, Pb and Zn) with a pH of 4.3±0.1 for 135 h. It was found that Pb immobilization was greater than either Cu or Zn. Zn is the most mobile among three and also has the highest variation in the observed degree of immobilization.

  2. A Novel Isoenzyme of CuZn-superoxide Dismutase from Nicotiana tobacum

    Institute of Scientific and Technical Information of China (English)

    Liang Quan SHENG; Shao Min LIU; Hou Rong XIAO; Bing Le XIA; Qing Liang LIU

    2004-01-01

    An isoenzyme of CuZn-superoxide dismutase, denoted as CuZnSODⅢ, has been separated and purified from Nicotiana Tobacum (tobacco) leaves to apparent homogeneity. Its molecular mass is 22976.6Da. It is composed of one subunit, which is consisted of 187 amine acid residues and contains 1 copper and 0.5 zinc atom. The activation energy of the thermal denaturation process has been obtained as about 143.5kJmol-1. Meanwhile, some properties of spectra were investigated.

  3. Cofiring behavior of NiCuZn ferrite/PMN ferroelectrics di-layer composites

    Institute of Scientific and Technical Information of China (English)

    MIAO Chun-lin; ZHOU Ji; YUE Zhen-xing; LI Long-tu

    2005-01-01

    The cofiring compatibility between ferrite and relaxor ferroelectrics materials is the key issue in the production of multilayer chip LC filters. The cofiring behavior, interfacial microstructure and diffusion of di-layer composites of NiCuZn ferrite/PMN relaxor ferroelectrics are studied. In order to analyze the matching condition of thermodynamic properties between ferrite and relaxor ferroelectric ceramics, TMA is performed on PMN ferroelectrics and NiCuZn ferrite with certain percentage of Bi2 O3, respectively. EDS results demonstrate that serious element diffusions exist at the interface, which is in accordance with the phase analysis based on XRD patterns.

  4. Quaternary Cu2ZnSnSe4 thin films for solar cells applications

    OpenAIRE

    Zoppi, Guillaume; Forbes, Ian; Miles, Robert; Dale, Phillip; Scragg, Jonathan; Peter, Laurence

    2009-01-01

    Polycrystalline thin films of Cu2ZnSnSe4 (CZTSe) were produced by selenisation of Cu(Zn,Sn) magnetron sputtered metallic precursors for solar cell applications. The p-type CZTSe absorber films were found to crystallize in the stannite structure (a = 5.684 Ã… and c = 11.353 Ã…) with an electronic bandgap of 0.9 eV. Solar cells with the structure were fabricated with device efficiencies up to 3.2%.

  5. Synthesis, surface characterization and optical properties of 3-thiopropionic acid capped ZnS:Cu nanocrystals

    Indian Academy of Sciences (India)

    Ashish Tiwari; S A Khan; R S Kher

    2011-08-01

    3-Thiopropionic acid (TPA) capped ZnS:Cu nanocrystals have been successfully synthesized by simple aqueous method. Powder X-ray diffraction (XRD) studies revealed the particle size to be 4.2 nm. Surface characterization of the nanocrystals by FTIR spectroscopy has been done and the structure for surface bound TPA based on spectral analysis was proposed. The optical studies were done using UV-VIS spectroscopy and particle size and diameter polydispersity index (DPI) were calculated. Photoluminescence (PL) spectrum reveals emission related to the transition from conduction band of ZnS to 2 level of Cu2+. Electron microscopy was also done by scanning electron microscopy (SEM).

  6. Prediction of Hardness of the Zn-Al-Cu Alloys of Agreement by Composition in Weight

    Directory of Open Access Journals (Sweden)

    Villegas-Cárdenas José David

    2013-06-01

    Full Text Available Ten alloys Zn – Al – Cu were developed in two parts, in agreement to two zones presented in the isopleth diagrams (Villas et al., 1995. The percentage of Cu and Al was systematically varied. Subsequently, hardness measurements were performed. These measurements allowed establishing two equations that predict the hardness with an error lower than 5%. With these equations, it is possible to obtain alloys that replace Al base alloys by a Zn base alloy, having the same hardness. This implicates also the elimination of the volumetric change in the presence of ε phase.

  7. HEAVY METALS (Ni, Cu, Zn AND Cd CONTENT IN SERUM OF RAT FED GREEN MUSSELS

    Directory of Open Access Journals (Sweden)

    Muhammad Yudhistira Azis

    2015-11-01

    Full Text Available Green mussel (Perna viridis can playing role as bio-indicator or biomonitoring agent for heavy-metalcontaminations in the sea. In this research, the concentrations of four elements Ni, Cu, Zn and Cd in P. viridis and in the serum of rat which orally feed by P. viridis were determined by Atomic Absorption Spectrometry (AAS following dry acid digestion. Parameter analysis was evaluated by determining confidence limit for the obtained results. The result showed that there was a sequence of heavy-metal content in green mussels sample and laboratory rats serum, such as Ni < Cd < Cu < Zn. Keywords: heavy metals, green mussels, laboratory rats serum, AAS

  8. Modeling and analysis of soybean (Glycine max. L Cu/Zn, Mn and Fe superoxide dismutases

    Directory of Open Access Journals (Sweden)

    V. Ramana Gopavajhula

    2013-01-01

    Full Text Available Superoxide dismutase (SOD, EC 1.15.1.1 is an important metal-containing antioxidant enzyme that provides the first line of defense against toxic superoxide radicals by catalyzing their dismutation to oxygen and hydrogen peroxide. SOD is classified into four metalloprotein isoforms, namely, Cu/Zn SOD, Mn SOD, Ni SOD and Fe SOD. The structural models of soybean SOD isoforms have not yet been solved. In this study, we describe structural models for soybean Cu/Zn SOD, Mn SOD and Fe SOD and provide insights into the molecular function of this metal-binding enzyme in improving tolerance to oxidative stress in plants.

  9. Effect of Deformation on Order-Disorder Phase Transformation in Cu-Zn Alloy

    Institute of Scientific and Technical Information of China (English)

    Zhang Ruijun; Xu Liang; Liu Jianhua

    2007-01-01

    The phase transformation temperature of ordered β' to disordered β in the Cu-Zn alloy was tested by DSC. The transformation activation energy was calculated and the effect of deformation of the phase transformation was discussed. The results show that the phase transformation temperature and activation energy of ordered β' to disordered β in the Cu-Zn alloy can be decreased going through deformation, and the phase transformation time can be also decreased. As a result, the order-disorder phase transformation occurs more easily.

  10. Analysis on Cu and Zn Concentrations in Agricultural Soils of Ili District, Xinjiang Autonomous Region, China

    Directory of Open Access Journals (Sweden)

    YANG Jing-na

    2015-02-01

    Full Text Available The aim of this work is mainly to investigate the contents of copper(Cuand zinc(Znin agricultural soils to provide basic infor-mation for the establishment of green and organic production base in Ili District, Xinjiang Autonomous Region. 600 topsoil samples of the a-gricultural land were collected from eight counties of Ili District, and the contents of Cu and Zn were determined by AAS after microwave di-gestion. The statistics analysis showed that the mean contents of Cu and Zn in the agricultural soils of Ili District were 28.68 mg·kg-1 and 83.17 mg·kg-1, respectively. The concentrations of Cu in the agricultural soils of Ili District ranged from 11.07 mg·kg-1 to 59.90 mg·kg-1, 85% of which ranged from 20 mg·kg-1 to 40 mg·kg-1; and the concentrations of Zn in the agricultural soils of Ili District ranged from 39.58 mg·kg-1 to 160.40 mg·kg-1, 90%of which ranged from 60 mg·kg-1 to 110 mg·kg-1. Furthermore, compared the Cu and Zn contents of the tested soils among the eight counties, Cu contents in Tekes County were higher than other counties, while Zn contents showed little difference. The con-tents of Cu and Zn in the tested soils were all below the threshold values that were established in the national environmental quality standard for soils(secondary standards, GB 15618-1995, but about 7% and 21% were higher than the Cu and Zn background values of soil in Ili District, respectively. Furthermore, the concentrations of Cu and Zn in soils of Ili District accord with the environmental requirements for or-ganic and green production base regulated by national standard of organic products(GB/T 19630-2011and industrial standard of green food(NY/T 391-2013.

  11. Structural and optical properties of Zn doped CuInS2 thin films

    Indian Academy of Sciences (India)

    Mahdi H Suhail

    2012-11-01

    Copper indium sulphide (CIS) films were deposited by spray pyrolysis onto glass substrates from aqueous solutions of copper (II) sulphate, indium chloride and thiourea using compressed air as the carrier gas. The copper/indium molar ratio (Cu/In) in the solution 1(1:1) and the sulphur/copper ratio (S/Cu) was fixed at 4. Structural properties of these films were characterized. The effects of Zn (0–5%)molecular weight compared with CuInS2 Source and different substrate temperatures on films properties were investigated using X-ray diffraction (XRD) and optical transmission spectra. Optical characteristics of the CuInS2 films have been analysed using spectrophotometer in the wavelength range 300–1100 nm. The absorption spectra of the films showed that this compound is a direct bandgap material and gap values varied between 1.55 and 1.57 eV, depending on the substrate temperatures. Zn-doped samples have a bandgap energy of 1.55–1.95 eV. It was observed that there is an increase in optical bandgap with increasing Zn % molecular weight. The optical constants of the deposited films were obtained from the analysis of the experimentally recorded transmission and absorption spectral data. The refractive index, n and dielectric constants, 1 and 2, were also discussed and calculated as a function of investigated wavelength range and found it dependent on Zn incorporation. We found that the Zn-doped CuInS2 thin films exhibit P-type conductivity and we predict that Zn species can be considered as suitable candidates for use as doped acceptors to fabricate CuInS2-based solar cells. The paper presents a study concerning the influence of deposition parameters (temperature of the substrate and concentration of Zn (1–5)% from 0.16 M ZnCl2) on the quality of CuInS2 thin films achieved by spray pyrolysis on glass substrate from solutions containing 0.02 M CuCl2.2H2O, 0.16 M thiourea and 0.08 M In2Cl3.5H2O.

  12. Room-temperature ferromagnetic properties of Cu-doped ZnO rod arrays

    Indian Academy of Sciences (India)

    C H Xia; C G Hu; C H Hu; Z Ping; F Wang

    2011-08-01

    We have investigated properties of the Cu-doped ZnO crystalline film synthesized by the hydrothermal method. X-ray diffraction and X-ray photoelectron spectroscopy results provide the evidence that Cu2+ is incorporated into the ZnO lattices. Photoluminescence spectrum of the rod arrays shows that the UV emission peak shifts a little to lower energy and its intensity decreased. There are another two emission peaks centred in blue and green regions because of the incorporation of Cu2+ ions. The rod arrays have exhibited room-temperature ferromagnetic behaviour with the remanence of 0.926 × 10-3 emu/cm3. We suggest that the exchange interaction between local spin-polarized electrons (such as the electrons of Cu2+ ions) and conductive electrons is the cause of room-temperature ferromagnetism.

  13. Fabrication of Cu2ZnSn(SxSe1 - x)4 solar cells by ethanol-ammonium solution process

    Science.gov (United States)

    Xue, Cong; Li, Jianmin; Wang, Yaguang; Jiang, Guoshun; Weifeng, Liu; Zhu, Changfei

    2016-10-01

    In this paper, Cu2ZnSn(SxSe1 - x)4 precursor films were produced by doctor blade process from SnS-Cu2O-ZnS slurry. To prepare the slurry, SnS, ZnS and Cu2O precipitates, which are outgrowths of stacked layer ZnS/Cu/SnS by CBD (chemical bath deposition)-annealing route, were dissolved in the mixture solvent of ethanol and NH3·H2O. Synthesized precursor films were then annealed at different conditions. The post-annealed films were characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman measurements and UV-vis-NIR spectroscopy. SEM studies reveal that the rough and relatively compact absorber thin films are obtained via the sulfidation and sulfidation-selenization processes. X-ray diffraction and Raman spectrum results verify that the obtained films are composed of Cu2ZnSnS4 and Cu2ZnSnSe4 phases, which have high absorbance in visible range and direct band gap energy of 1.01-1.47 eV. The best devices yield total area power conversion efficiency of 1.99% and 2.95% corresponding to Cu2ZnSnS4 and Cu2ZnSn(SxSe1 - x)4 thin film solar cells under AM1.5 illumination without any anti-reflection layer.

  14. Overexpressing the Sedum alfredii Cu/Zn Superoxide Dismutase Increased Resistance to Oxidative Stress in Transgenic Arabidopsis

    Directory of Open Access Journals (Sweden)

    Zhen Li

    2017-06-01

    Full Text Available Superoxide dismutase (SOD is a very important reactive oxygen species (ROS-scavenging enzyme. In this study, the functions of a Cu/Zn SOD gene (SaCu/Zn SOD, from Sedum alfredii, a cadmium (Cd/zinc/lead co-hyperaccumulator of the Crassulaceae, was characterized. The expression of SaCu/Zn SOD was induced by Cd stress. Compared with wild-type (WT plants, overexpression of SaCu/Zn SOD gene in transgenic Arabidopsis plants enhanced the antioxidative defense capacity, including SOD and peroxidase activities. Additionally, it reduced the damage associated with the overproduction of hydrogen peroxide (H2O2 and superoxide radicals (O2•-. The influence of Cd stress on ion flux across the root surface showed that overexpressing SaCu/Zn SOD in transgenic Arabidopsis plants has greater Cd uptake capacity existed in roots. A co-expression network based on microarray data showed possible oxidative regulation in Arabidopsis after Cd-induced oxidative stress, suggesting that SaCu/Zn SOD may participate in this network and enhance ROS-scavenging capability under Cd stress. Taken together, these results suggest that overexpressing SaCu/Zn SOD increased oxidative stress resistance in transgenic Arabidopsis and provide useful information for understanding the role of SaCu/Zn SOD in response to abiotic stress.

  15. Microstructures and optical properties of Cu-doped ZnO films prepared by radio frequency reactive magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Ma Ligang [College of physics and Electronics Engineering, Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province, Northwest Normal University, Lanzhou, Gansu, 730070 (China); Ma Shuyi, E-mail: maligang186@163.com [College of physics and Electronics Engineering, Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province, Northwest Normal University, Lanzhou, Gansu, 730070 (China); Chen Haixia; Ai Xiaoqian; Huang Xinli [College of physics and Electronics Engineering, Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province, Northwest Normal University, Lanzhou, Gansu, 730070 (China)

    2011-09-15

    Pure and Cu-doped ZnO (ZnO:Cu) thin films were deposited on glass substrates using radio frequency (RF) reactive magnetron sputtering. The effect of substrate temperature on the crystallization behavior and optical properties of the ZnO:Cu films have been studied. The crystal structures, surface morphology and optical properties of the films were systematically investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and a fluorescence spectrophotometer, respectively. The results indicated that ZnO films showed a stronger preferred orientation toward the c-axis and a more uniform grain size after Cu-doping. As for ZnO:Cu films, the full width at half maxima (FWHM) of (0 0 2) diffraction peaks decreased first and then increased, reaching a minimum of about 0.42 deg. at 350 deg. C and the compressive stress of ZnO:Cu decreased gradually with the increase of substrate temperature. The photoluminescence (PL) spectra measured at room temperature revealed two blue and two green emissions. Intense blue-green luminescence was obtained from the sample deposited at higher substrate temperature. Finally, we discussed the influence of annealing temperature on the structural and optical properties of ZnO:Cu films. The quality of ZnO:Cu film was markedly improved and the intensity of blue peak ({approx}485 nm) and green peak ({approx}527 nm) increased noticeably after annealing. The origin of these emissions was discussed.

  16. Inhibition effect of expression of Cu/Zn superoxide dismutase from rice on synthesis of Glutathione in Saccharomyces cerevisiae

    Institute of Scientific and Technical Information of China (English)

    AI Yu-zhuo; DU Ye-jie; ZU Yuan-gang; AN Zhi-gang

    2008-01-01

    The expression of a rice Cu/Zn superoxide dismutase (Cu/Zn-SOD) in Saccharomyces cerevisiae regulated by GAPDH promoter, involved in the inhibition of endogenous Glutathione (GSH) synthesis, and the competitive expression was detected by constructing the expression vector transferred Cu/Zn-SOD gene into wild-type S. Cerevisiae. Transcription and expression of the Cu/Zn-SOD gene in S. Cerevisiawere were confirmed by northern blot and SDS-PAGE, respectively, and activity of the Cu/Zn-SOD from crude extracts was enzymatically detected based on the effect of nitroblue tetrazolium (NBT) after running a native polyacrylamide gel. The GSH synthesis was also tested by DTNB (5, 5′-Dithiobis (2-nitrobenzoic acid)) method. Results showed that GSH synthesis was evidently suppressed by the expression of Cu/Zn-SOD gene in both control and heat shock strains. It implied that the expression of the Cu/Zn-SOD gene in S. Cerevisiae has more potential facility in response to oxidative exposure than that of endogenous GSH, although Cu/Zn-SOD and GSH were both contributed to the function of oxygen radical oxidoreduction.

  17. Band structures of Cu2ZnSnS4 and Cu2ZnSnSe4 from many-body methods

    Science.gov (United States)

    Botti, Silvana; Kammerlander, David; Marques, Miguel A. L.

    2011-06-01

    We calculate the band structures of kesterite and stannite Cu2ZnSnS4 and Cu2ZnSnSe4, using a state-of-the-art self-consistent GW approach. Our accurate quasiparticle states allow to discuss: the dependence of the gap on the anion displacement; the key-role of the nonlocality of the exchange-correlation potential to obtain good structural parameters; the reliability of less expensive hybrid functional and generalized gradient approximation+U approaches. In particular, we show that even if the band gap is correctly reproduced by hybrid functionals, the band-edge corrections are in disagreement with self-consistent GW results, which have decisive implications for the positioning of the defect levels in the band gap.

  18. Biosorption behaviors of Cu2+,Zn2+, Cd2+ and mixture by waste activated sludge

    Institute of Scientific and Technical Information of China (English)

    LUO Sheng-lian; YUAN Lin; CHAI Li-yuan; MIN Xiao-bo; WANG Yun-yan; FANG Yan; WANG Pu

    2006-01-01

    Biosorption of heavy metal ions, such as Cu2+, Cd2+ and Zn2+, was carried out using waste activated sludge from municipal sewage treatment plant as adsorption material, and the effects of parameters, such as pH value, temperature, reaction time and sorption duration, were studied in detail. The results indicate that the removal rates of Cu2+, Zn2+ and Cd2+ with low concentration are 96.47%, 80% and 90%, respectively, adsorbed by waste activated sludge. Little effect of dosage of activated sludge on the adsorption of Cu2+ and more effects on the adsorption of Zn2+ and Cd2+ are observed. Little effect oftemperature is observed, while pH value and adsorption time exert important influence on the sorption process. The adsorption behaviors of heavy metal ions all have parabolic relationships with pH value. The optimum pH value is between 6 and 10, and the optimum adsorption time is 1 h. In single heavy metal ion system, the sorption processes of Cu2+, Zn2+ and Cd2+ are in accordance with Freundlich model, which indicates that it is suitable for the treatment of these three heavy metal ions using intermittent operation. In addition, the sorption capacity of the sludge for Cu2+ is preferential to the other two ions.

  19. Cyclotron production of {sup 64}Cu by deuteron irradiation of {sup 64}Zn

    Energy Technology Data Exchange (ETDEWEB)

    Abbas, K. [Institute for Health and Consumer Protection, Joint Research Centre, European Commission, TP 500, I-21020 Ispra (Vatican City State, Holy See,) (Italy)]. E-mail: kamel.abbas@jrc.it; Kozempel, J. [Institute for Health and Consumer Protection, Joint Research Centre, European Commission, TP 500, I-21020 Ispra (VA) (Italy); Charles University Prague, Faculty of Science, Department of Organic and Nuclear Chemistry, 128 43 Prague (Czech Republic); Bonardi, M. [LASA, Radiochemistry Laboratory, University and INFN, via F.lli Cervi 201, I-20090 Segrate (MI) (Italy); Groppi, F. [LASA, Radiochemistry Laboratory, University and INFN, via F.lli Cervi 201, I-20090 Segrate (MI) (Italy); Alfarano, A. [Institute for Health and Consumer Protection, Joint Research Centre, European Commission, TP 500, I-21020 Ispra (VA) (Italy); Holzwarth, U. [Institute for Health and Consumer Protection, Joint Research Centre, European Commission, TP 500, I-21020 Ispra (VA) (Italy); Simonelli, F. [Institute for Health and Consumer Protection, Joint Research Centre, European Commission, TP 500, I-21020 Ispra (VA) (Italy); Hofman, H. [Institute for Health and Consumer Protection, Joint Research Centre, European Commission, TP 500, I-21020 Ispra (VA) (Italy); Horstmann, W. [Institute for Health and Consumer Protection, Joint Research Centre, European Commission, TP 500, I-21020 Ispra (VA) (Italy); Menapace, E. [ENEA, Applied Physics Division, Bologna (Italy); Leseticky, L. [Charles University Prague, Faculty of Science, Department of Organic and Nuclear Chemistry, 128 43 Prague (Czech Republic); Gibson, N. [Institute for Health and Consumer Protection, Joint Research Centre, European Commission, TP 500, I-21020 Ispra (VA) (Italy)

    2006-09-15

    The short-lived (12.7 h half-life) {sup 64}Cu radioisotope is both a {beta} {sup +} and a {beta} {sup -} emitter. This property makes {sup 64}Cu a promising candidate for novel medical applications, since it can be used simultaneously for therapeutic application of radiolabelled biomolecules and for diagnosis with PET. Following previous work on {sup 64}Cu production by deuteron irradiation of natural zinc, we report here the production of this radioisotope by deuteron irradiation of enriched {sup 64}Zn. In addition, yields of other radioisotopes such as {sup 61}Cu, {sup 67}Cu, {sup 65}Zn, {sup 69m}Zn, {sup 66}Ga and {sup 67}Ga, which were co-produced in this process, were also measured. The evaporation code ALICE-91 and the transport code SRIM 2003 were used to determine the excitation functions and the stopping power, respectively. All the nuclear reactions yielding the above-mentioned radioisotopes were taken into account in the calculations both for the natural and enriched Zn targets. The experimental and calculated yields were shown to be in reasonable agreement. The work was carried out at the Scanditronix MC-40 Cyclotron of the Institute for Health and Consumer Protection of the Joint Research Centre of the European Commission (Ispra site, Italy). The irradiations were carried out with 19.5 MeV deuterons, the maximum deuteron energy obtainable with the MC-40 cyclotron.

  20. Trap and recombination centers study in sprayed Cu2ZnSnS4 thin films

    Science.gov (United States)

    Courel, Maykel; Vigil-Galán, O.; Jiménez-Olarte, D.; Espíndola-Rodríguez, M.; Saucedo, E.

    2014-10-01

    In this work, a study of trap and recombination center properties in polycrystalline Cu2ZnSnS4 thin films is carried out in order to understand the poor performance in Cu2ZnSnS4 thin film solar cells. Thermally stimulated current has been studied in Cu2ZnSnS4 deposited by pneumatic spray pyrolysis method using various heating rates, in order to gain information about trap centers and/or deep levels present within the band-gap of this material. A set of temperature-dependent current curves revealed three levels with activation energy of 126 ± 10, 476 ± 25, and 1100 ± 100 meV. The possible nature of the three levels found is presented, in which the first one is likely to be related to CuZn antisites, while second and third to Sn vacancies and SnCu antisites, respectively. The values of frequency factor, capture cross section, and trap concentration have been determined for each center.

  1. Ab initio investigation on hydrogen adsorption capability in Zn and Cu-based metal organic frameworks

    Energy Technology Data Exchange (ETDEWEB)

    Tanuwijaya, V. V., E-mail: viny.veronika@gmail.com [Engineering Physics, Faculty of Industrial Technology, Institut Teknologi Bandung Jalan Ganeca 10 Gd. T.P. Rachmat, Bandung 40132 (Indonesia); Hidayat, N. N., E-mail: avantgarde.vee@gmail.com; Agusta, M. K., E-mail: kemal@fti.itb.ac.id; Dipojono, H. K., E-mail: dipojono@tf.itb.ac.id

    2015-09-30

    One of the biggest challenge in material technology for hydrogen storage application is to increase hydrogen uptake in room temperature and pressure. As a class of highly porous material, Metal-Organic Frameworks (MOF) holds great potential with its tunable structure. However, little is known about the effect of metal cluster to its hydrogen storage capability. Investigation on this matter has been carried out carefully on small cluster of Zn and Cu-based MOF using first principles method. The calculation of two distinct building units of MOFs, namely octahedral and paddle-wheel models, have been done with B3LYP density functional method using 6-31G(d,p) and LANL2DZ basis sets. From geometry optimization of Zn-based MOF linked by benzene-dicarboxylate (MOF-5), it is found that hydrogen tends to keep distance from metal cluster group and stays above benzene ring. In the other hand, hydrogen molecule prefers to stay atop of the exposed Cu atom in Cu-based MOF system linked by the same linker group (Cu-bdc). Calculated hydrogen binding enthalpies for Zn and Cu octahedral cages at ZnO{sub 3} sites are 1.64kJ/mol and 2.73kJ/mol respectively, while hydrogen binding enthalpies for Zn and Cu paddle-wheel cages calculated on top of metal atoms are found to be at 6.05kJ/mol and 6.10kJ/mol respectively. Major difference between Zn-MOF-5 and Cu-bdc hydrogen uptake performance might be caused by unsaturated metal sites present in Cu-bdc system and the influence of their geometric structures, although a small difference on binding energy in the type of transition metal used is also observed. The comparison between Zn and Cu-based MOF may contribute to a comprehensive understanding of metal clusters and the importance of selecting best transition metal for design and synthesis of metal-organic frameworks.

  2. Ab initio investigation on hydrogen adsorption capability in Zn and Cu-based metal organic frameworks

    Science.gov (United States)

    Tanuwijaya, V. V.; Hidayat, N. N.; Agusta, M. K.; Dipojono, H. K.

    2015-09-01

    One of the biggest challenge in material technology for hydrogen storage application is to increase hydrogen uptake in room temperature and pressure. As a class of highly porous material, Metal-Organic Frameworks (MOF) holds great potential with its tunable structure. However, little is known about the effect of metal cluster to its hydrogen storage capability. Investigation on this matter has been carried out carefully on small cluster of Zn and Cu-based MOF using first principles method. The calculation of two distinct building units of MOFs, namely octahedral and paddle-wheel models, have been done with B3LYP density functional method using 6-31G(d,p) and LANL2DZ basis sets. From geometry optimization of Zn-based MOF linked by benzene-dicarboxylate (MOF-5), it is found that hydrogen tends to keep distance from metal cluster group and stays above benzene ring. In the other hand, hydrogen molecule prefers to stay atop of the exposed Cu atom in Cu-based MOF system linked by the same linker group (Cu-bdc). Calculated hydrogen binding enthalpies for Zn and Cu octahedral cages at ZnO3 sites are 1.64kJ/mol and 2.73kJ/mol respectively, while hydrogen binding enthalpies for Zn and Cu paddle-wheel cages calculated on top of metal atoms are found to be at 6.05kJ/mol and 6.10kJ/mol respectively. Major difference between Zn-MOF-5 and Cu-bdc hydrogen uptake performance might be caused by unsaturated metal sites present in Cu-bdc system and the influence of their geometric structures, although a small difference on binding energy in the type of transition metal used is also observed. The comparison between Zn and Cu-based MOF may contribute to a comprehensive understanding of metal clusters and the importance of selecting best transition metal for design and synthesis of metal-organic frameworks.

  3. Electrodeposited ZnO/Cu{sub 2}O heterojunction solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, S.S.; Mittiga, A.; Salza, E.; Masci, A.; Passerini, S. [Agency for the New Technologies, Energy and the Environment (ENEA), Casaccia Research Center, Via Anguillarese 301, 00123 Rome (Italy)

    2008-01-01

    In this paper the fabrication and the characterization of heterojunction solar cells based on electrodeposited ZnO and Cu{sub 2}O is described. The effect of the electrodeposition conditions (pH and temperature) on the cell performance has been investigated. The cells made with a Cu{sub 2}O layer deposited at high pH (12) and moderate temperature (50 C) have shown conversion efficiency as high as 0.41%. (author)

  4. Intermetallic compound formation at Sn-3.0Ag-0.5Cu-1.0Zn lead-free solder alloy/Cu interface during as-soldered and as-aged conditions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Feng-Jiang [Department of Materials Science and Engineering, Shanghai University of Engineering Science, Shanghai 201620 (China)]. E-mail: wangfjy@yahoo.com.cn; Yu, Zhi-Shui [Department of Materials Science and Engineering, Shanghai University of Engineering Science, Shanghai 201620 (China); Qi, Kai [Department of Materials Science and Engineering, Shanghai University of Engineering Science, Shanghai 201620 (China)

    2007-07-12

    Intermetallic formations of Sn-3.0Ag-0.5Cu solder alloy with additional 1.0 wt% Zn were investigated for Cu-substrate during soldering and isothermal aging. During soldering condition, the Cu{sub 5}Zn{sub 8} compound with granular-type morphology is the interfacial IMC for Sn-3.0Ag-0.5Cu-1.0Zn solder, while the Cu{sub 6}Sn{sub 5} compound with scallop-type morphology is the interfacial IMC for Sn-3.0Ag-0.5Cu solder. During thermal aging, the final interfacial structure for Sn-3.0Ag-0.5Cu-1.0Zn solder is solder/Cu{sub 5}Zn{sub 8}/Cu{sub 6}Sn{sub 5}/Cu{sub 3}Sn/Cu, different from the solder/Cu{sub 6}Sn{sub 5}/Cu{sub 3}Sn/Cu for Sn-3.0Ag-0.5Cu solder. The thickness of Cu-Sn IMC layers increases, while the thickness of Cu{sub 5}Zn{sub 8} compound layer decreases with increasing aging time due to the decomposition of the Cu{sub 5}Zn{sub 8} layer by the diffusion of Cu and Zn atoms into the solder and Cu{sub 6}Sn{sub 5} at higher aging temperature. For Sn-3.0Ag-0.5Cu-1.0Zn solder, at higher aging temperature of 150 or 175 {sup o}C, with the formation of Cu{sub 3}Sn at Cu{sub 6}Sn{sub 5}/Cu, Kirkendall voids can be observed at the interface of Cu{sub 3}Sn/Cu.

  5. EXAFS analysis of a human Cu,Zn SOD isoform focused using non-denaturing gel electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Chevreux, Sylviane; Roudeau, Stephane; Deves, Guillaume; Ortega, Richard [Laboratoire de Chimie Nucleaire Analytique et Bioenvironnementale, CNRS UMR5084, Universite Bordeaux 1, Chemin du Solarium, F-33175 Gradignan cedex (France); Solari, Pier Lorenzo [Synchrotron SOLEIL, L' Orme des Merisiers, BP 48, F-91192 Gif-sur-Yvette cedex, Saint-Aubin (France); Alliot, Isabelle; Testemale, Denis; Hazemann, Jean Louis, E-mail: ortega@cenbg.in2p3.f [FAME, ESRF, 6 rue Jules Horowitz, BP220, F-38043 Grenoble cedex (France)

    2009-11-15

    Isoelectric point isoforms of a metalloprotein, copper-zinc superoxide dismutase (CuZnSOD), separated on electrophoresis gels were analyzed using X-ray Absorption Spectroscopy. Mutations of this protein are involved in familial cases of amyotrophic lateral sclerosis. The toxicity of mutants could be relied to defects in the metallation state. Our purpose is to establish analytical protocols to study metallation state of protein isoforms such as those from CuZnSOD. We previously highlighted differences in the copper oxidation state between CuZnSOD isoforms using XANES. Here, we present the first results for EXAFS analyses performed at Cu and Zn K-edge on the majoritary expressed isoform of human CuZnSOD separated on electrophoresis gels.

  6. Pyrroloquinoline quinone from Gluconobacter oxydans fermentation broth enhances superoxide anion-scavenging capacity of Cu/Zn-SOD.

    Science.gov (United States)

    Ma, Ke; Cui, Jun-Zhu; Ye, Jian-Bin; Hu, Xian-Mei; Ma, Ge-Li; Yang, Xue-Peng

    2017-09-01

    A bioassay-guided fractionation of extract from Gluconobacter oxydans fermentation broth afforded Compound 1, which was identified as pyrroloquinoline quinone (PQQ) by spectroscopic methods. PQQ has been shown to enhance the superoxide anion-scavenging capacity significantly for Cu/Zn-SOD. To illustrate the mechanism, the interaction between PQQ and Cu/Zn-SOD was investigated. The multiple binding sites involving hydrogen bonds and van der Waals force between PQQ and Cu/Zn-SOD were revealed by isothermal titration calorimetry. The α-helix content was increased in the Cu/Zn-SOD structure with the addition of PQQ into the solution through ultraviolet (UV) spectroscopy. These results indicated that PQQ could change the conformation of Cu/Zn-SOD through interaction, which could enhance its superoxide anion-scavenging capacity. Therefore, PQQ is a potential natural antioxidant. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Size-dependent dual emission of Cu,Mn:ZnSe QDs: Controlling both emission wavelength and intensity.

    Science.gov (United States)

    Xu, Shuhong; Jiang, Han; Dong, Renjie; Lv, Changgui; Wang, Chunlei; Cui, Yiping

    2017-06-01

    Cu,Mn:ZnSe quantum dots (QDs) of tunable size, controllable photoluminescence (PL) intensity ratio and PL range were prepared. A study of the experimental conditions confirmed that the size of Cu,Mn:ZnSe QDs is affected by the pH of the solution, the speed at which the Zn solution is injected and the reaction temperature. In general, high pH, low injection speed and high reaction temperature are optimal for preparing large QDs. Based on this knowledge, different sizes of Cu,Mn:ZnSe QDs were synthesized. Moreover, white emission Cu,Mn:ZnSe QDs were designed by controlling the experimental conditions and the feeding mole ratio of Mn:Cu. Copyright © 2017 John Wiley & Sons, Ltd.

  8. Low-Temperature Sintering and Electromagnetic Properties of NiCuZn/CaTiO3 Composites

    Science.gov (United States)

    Yang, Haibo; Yang, Yanyan; Lin, Ying; Zhu, Jianfeng; Wang, Fen

    2012-04-01

    Dense CaTiO3/Ni0.37Cu0.20Zn0.43Fe1.92O3.88 (CTO/NiCuZn) composites were prepared by the conventional solid-state reaction method and sintered at 950°C. The phase compositions and surface morphologies of the composites were investigated using x-ray diffraction and scanning electron microscopy, respectively. The dielectric and magnetic properties of the composites were also investigated. The results show that the CTO/NiCuZn composites possess high dielectric constants and permeabilities, which can be used in high-frequency communications for capacitor-inductor integrating devices such as electromagnetic interference filters and antennas. With increasing NiCuZn concentration, the permeabilities of the CTO/NiCuZn composites increase, while the dielectric constants and cutoff frequencies decrease.

  9. Electrochemical behavior of Cu-Zn-Al shape memory alloy after surface modification by electroless plated Ni-P

    Institute of Scientific and Technical Information of China (English)

    LIANG Chenghao; CHEN Bangyi; CHEN Wan; WANG Hua

    2004-01-01

    The electrochemical behavior of Cu-Zn-Al shape memory alloy (SMA) with and without electroless plated Ni-P was investigated by electrochemical methods in artificial Tyrode's solution. The results showed that Cu-Zn-Al SMA engendered dezincification corrosion in Tyrode's solution. The anodic active current densities as well as electrochemical dissolution sensitivity of the electroless plated Ni-P Cu-Zn-Al SMA increased with NaCl concentration rising, pH of solution decreasing and environmental temperature uprising. X-ray diffraction analysis indicated that after surface modification by electroless plated Ni-P, an amorphous plated film formed on the surface of Cu-Zn-Al SMA. This film can effectively isolate matrix metal from corrosion media and significantly improve the electrochemical property of Cu-Zn-Al SMA in artificial Tyrode's solution.

  10. EXAFS analysis of a human Cu,Zn SOD isoform focused using non-denaturing gel electrophoresis

    Science.gov (United States)

    Chevreux, Sylviane; Solari, Pier Lorenzo; Roudeau, Stéphane; Deves, Guillaume; Alliot, Isabelle; Testemale, Denis; Hazemann, Jean Louis; Ortega, Richard

    2009-11-01

    Isoelectric point isoforms of a metalloprotein, copper-zinc superoxide dismutase (CuZnSOD), separated on electrophoresis gels were analyzed using X-ray Absorption Spectroscopy. Mutations of this protein are involved in familial cases of amyotrophic lateral sclerosis. The toxicity of mutants could be relied to defects in the metallation state. Our purpose is to establish analytical protocols to study metallation state of protein isoforms such as those from CuZnSOD. We previously highlighted differences in the copper oxidation state between CuZnSOD isoforms using XANES. Here, we present the first results for EXAFS analyses performed at Cu and Zn K-edge on the majoritary expressed isoform of human CuZnSOD separated on electrophoresis gels.

  11. Interface morphology and solute partition during directional soldification process of Al-1.5Cu-3Zn alloy

    Energy Technology Data Exchange (ETDEWEB)

    Fuyia Chen; Wanqib Jie [State Key Lab. of Solidification Processing, Northwestern Polytechnical Univ., Xian (China)

    2005-07-01

    Interface morphology and solute partition during directional solidification process of Al-1.5Cu-3.0Zn alloy were investigated at temperature gradient of 80 K/cm and growth rate between 0.1 and 7.1 {mu}m/s. The solid-liquid interface was quenched during directional solidification and the micromorphology at the longitudinal section was examined by optic microscopy and SEM. The cellular growth interface and dendritic growth interface were observed and characterized. The distribution of Cu and Zn was measured by EDS, the equilibrium solute partition coefficients for Cu and Zn in Al-1.5Cu-3.0Zn alloy were obtained to be 0.31 and 0.58. The activity model and concentration model, developed by present authors, were used to calculate the equilibrium solute partition coefficients in Al-1.5Cu-3Zn alloy. The model-calculated results were compared with experimental data. (orig.)

  12. A novel pyrazole biscoumarin based chemosensors for the selective detection of Cu(2+) and Zn(2+) ions.

    Science.gov (United States)

    Kandasamy, Karthikeyan; Ganesabaskaran, Sivaprasad; Pachamuthu, Muthusamy Poomalai; Ramanathan, Anand

    2015-09-05

    A novel chemosensor based on pyrazole biscoumarin molecule "4-hydroxy-3-((4-hydroxy-2-oxo-2H-chromen-3-yl)(1,3-diphenyl-1H-pyrazol-4-yl)methyl)-2H-chromen-2-one" (PBC) was synthesized by a simple method. The chemosensing properties of PBC towards transition metal ions like Cu(2+) and Zn(2+) by naked eye, UV-Visible and fluorescence spectroscopic methods were described. The PBC solution with Cu(2+) and Zn(2+) ion showed brown and blue colour respectively. The UV-Visible spectra of PBC with Cu(2+) and Zn(2+) ions exposed their corresponding absorption maxima. Further, the Job's plot method confirmed the 1:1 and 2:1 stoichiometry of the complex formation between the PBC with Cu(2+) and Zn(2+) ions respectively. The fluorescence enhancement of PBC on binding with Cu(2+) and Zn(2+) is due to the inhibition of photo induced electron transfer mechanism.

  13. A novel pyrazole biscoumarin based chemosensors for the selective detection of Cu2+ and Zn2+ ions

    Science.gov (United States)

    Kandasamy, Karthikeyan; Ganesabaskaran, Sivaprasad; Pachamuthu, Muthusamy Poomalai; Ramanathan, Anand

    2015-09-01

    A novel chemosensor based on pyrazole biscoumarin molecule "4-hydroxy-3-((4-hydroxy-2-oxo-2H-chromen-3-yl)(1,3-diphenyl-1H-pyrazol-4-yl)methyl)-2H-chromen-2-one" (PBC) was synthesized by a simple method. The chemosensing properties of PBC towards transition metal ions like Cu2+ and Zn2+ by naked eye, UV-Visible and fluorescence spectroscopic methods were described. The PBC solution with Cu2+ and Zn2+ ion showed brown and blue colour respectively. The UV-Visible spectra of PBC with Cu2+ and Zn2+ ions exposed their corresponding absorption maxima. Further, the Job's plot method confirmed the 1:1 and 2:1 stoichiometry of the complex formation between the PBC with Cu2+ and Zn2+ ions respectively. The fluorescence enhancement of PBC on binding with Cu2+ and Zn2+ is due to the inhibition of photo induced electron transfer mechanism.

  14. Cu2ZnSnSe4 Thin Films by Selenization of Simultaneously Evaporated Sn-Zn-Cu Metallic Lays for Photovoltaic Applications

    Science.gov (United States)

    Shao, Lexi; Zhang, Jun; Zou, Changwei; Xie, Wei

    Cu2ZnSnSe4 (CZTSe) thin films were prepared by selenization of simultaneously evaporated metallic Cu-Zn-Sn on soda lime glass (SLG) substrates. The selenization were performed in elemental selenium vapor ambient at 450 °C for 1.5 h using Argon as the carrier gas. The compositions and structural properties of the films were characterized by using EDS, XRD, and Raman, respectively. The results show that the synthesized CZTSe thin films are nearly stoichiometric and single-phase with a kesterite structure. The measurement for electrical and optical properties indicated that a high absorption coefficient of 104 cm-1 and a low resistivity of 30 Ωcm are obtained. The optical band-gap energy of the CZTSe thin film can be fitted to be as 1.52 eV, which closes to the optimum value for solar cell absorber. The preparation processing for CZTSe developed in this woek is more attractive than others reported in the industrialization applications because the atomic ratio of Cu:Sn:Zn in the precursor can be easily controlled by adjusting the ratio of the evaporation sources, meanwhile, it is more suitable for large-scale production.

  15. The remarkable activity and stability of a highly dispersive beta-brass Cu-Zn catalyst for the production of ethylene glycol

    OpenAIRE

    Molly Meng-Jung Li; Jianwei Zheng; Jin Qu; Fenglin Liao; Elizabeth Raine; Winson C. H. Kuo; Shei Sia Su; Pang Po; Youzhu Yuan; Shik Chi Edman Tsang

    2016-01-01

    Incorporation of Zn atoms into a nanosize Cu lattice is known to alter the electronic properties of Cu, improving catalytic performance in a number of industrially important reactions. However the structural influence of Zn on the Cu phase is not well studied. Here, we show that Cu nano-clusters modified with increasing concentration of Zn, derived from ZnO support doped with Ga3+, can dramatically enhance their stability against metal sintering. As a result, the hydrogenation of dimethyl oxa...

  16. Structural, magnetic and transport properties of CoZn/Cu electrodeposited multilayers

    Energy Technology Data Exchange (ETDEWEB)

    El Bahraoui, T.; Errahmani, H.; Berrada, A. E-mail: alamal29@hotmail.com; Dinia, A.; Schmerber, G.; Cherkaoui El Moursli, F.; Hajji, F.; Lassri, H

    2004-05-01

    We present experimental results of (Co{sub 9.7}Zn{sub 90.3}/Cu){sub 20} multilayers grown from electrochemical dual bath. X-ray diffraction patterns have shown that the CoZn structural lattice parameters are close to those of the monoclinic CoZn{sub 13} compound. The magnetic properties at room temperature reveal both superparamagnetic and ferromagnetic features. The magnetoresistance behaviour exhibits a broad, rounded maximum around H=0 and does not present any saturation.

  17. Preparation and Characterization of Cu2ZnSnS4 Thin Films and Solar Cells Fabricated from Quaternary Cu-Zn-Sn-S Target

    Directory of Open Access Journals (Sweden)

    Min Xie

    2013-01-01

    Full Text Available CZTS thin films were fabricated through sputtering from a quaternary Cu-Zn-Sn-S target, followed by a sulfurization process. CZTS thin-film solar cells were also fabricated and a highest efficiency of 4.04% was achieved. It has been found that obvious Zn loss occurs during the sputtering and poorly crystallized CZTS are formed in the sputtered films. The Zn loss leads to the appearance of SnS. A sulfurization process can obviously improve the crystallinity of CZTS and films with grain size of several hundred nanometers can be obtained after sulfurization. The optical band gap of the films is estimated to be 1.57 eV. The electrical properties of the 4.04% efficient solar cell were investigated and it has been found that cell has obvious deficiency in minority carrier lifetime. This deficiency should be responsible for the low Jsc and low Voc of our cell.

  18. Solid Liquid Interdiffusion Bonding of Zn4Sb3 Thermoelectric Material with Cu Electrode

    Science.gov (United States)

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

    2016-10-01

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

  19. Application of 67Cu Produced by 68Zn(n,n'p+d)67Cu to Biodistribution Study in Tumor-Bearing Mice

    Science.gov (United States)

    Sugo, Yumi; Hashimoto, Kazuyuki; Kawabata, Masako; Saeki, Hideya; Sato, Shunichi; Tsukada, Kazuaki; Nagai, Yasuki

    2017-02-01

    67Cu produced by the 68Zn(n,n'p+d)67Cu reaction was used for the first time to determine the biodistribution of 67CuCl2 in colorectal tumor-bearing mice. A high uptake of 67Cu was observed in the tumor as well as in the liver and kidney, which are the major organs for copper metabolism. The result showing 67Cu accumulation in the tumor suggests that 67CuCl2 can be a potential radionuclide agent for cancer radiotherapy. It should also encourage further studies on the therapeutic effect on small animals using an increased dose of 67Cu produced by the 68Zn(n,n'p+d)67Cu reaction using presently available intense neutrons.

  20. Transient and modulated charge separation at CuInSe2/C60 and CuInSe2/ZnPc hybrid interfaces

    Science.gov (United States)

    von Morzé, Natascha; Dittrich, Thomas; Calvet, Wolfram; Lauermann, Iver; Rusu, Marin

    2017-02-01

    Spectral dependent charge transfer and exciton dissociation have been investigated at hybrid interfaces between inorganic polycrystalline CuInSe2 (untreated and Na-conditioned) thin films and organic C60 as well as zinc phthalocyanine (ZnPc) layers by transient and modulated surface photovoltage measurements. The stoichiometry and electronic properties of the bare CuInSe2 surface were characterized by photoelectron spectroscopy which revealed a Cu-poor phase with n-type features. After the deposition of the C60 layer, a strong band bending at the CuInSe2 surface was observed. Evidence for dissociation of excitons followed by charge separation was found at the CuInSe2/ZnPc interface. The Cu-poor layer at the CuInSe2 surface was found to be crucial for transient and modulated charge separation at CuInSe2/organic hybrid interfaces.

  1. Effect of the dietary oregano (Origanum vulgare) on Cu and Zn balance in weaned piglets.

    Science.gov (United States)

    Untea, Arabela; Criste, Rodica; Panaite, Tatiana; Costache, Iulian

    2011-01-01

    A 4-week study conducted on 20 weaned piglets (average initial weight 15 kg) evaluated the effects of dietary oregano (Origanum vulgare) used in the presence/absence of phytase on the Cu and Zn balance, while reducing/eliminating their inclusion in the diet as inorganic salts. Oregano was harvested from the wild flora. The Cu and Zn concentrations that were taken into consideration (9.85 ppm and 53.31 pmm, respectively) were the consensus values obtained in an interlaboratory study. The piglets were assigned to 4 groups (C, E1, E2, E3), housed in individual metabolic cages and fed on corn-soybean meal-based diets. The diet of the control group (C) with addition of 1% inorganic mineral premix (MP), contained: 40.92 ppm Cu, 144.96 ppm Zn. The experimental diets differed from the C diet as follows: E1--3% oregano, 0% phytase (5000 PU/g), 0% MP; E2--3% oregano, 0.01% phytase, 0% MP; E3--3% oregano, 0% phytase, 0.5% MP, E4--3% oregano, 0.01% phytase, 0,5% premix. For groups E1, E2, E3 and E4, 0.5% Zn of the MP were included in the diet, because the dietary oregano amount did not meet the requirements (NRC) for piglets. The mineral balance was determined during 3 periods of 5 days each. The levels of Cu and Zn were measured by FAAS in the samples (weekly samples/piglet) of ingesta, faeces and urine. It was noticed that although the dietary Cu ingested by the groups without MP was 75% (10.08 ppm) lower than C, the absorption coefficients were only 47% (28.83) lower than for group C (54.22%), while in the groups with 0.5% MP, the absorption was just 10% (48.86%) lower than for group C. For Zn, where the amount ingested by the experimental groups was 33% (97.62 ppm) lower than for group C, the absorption coefficients were just 20% (46.3%) lower than for group C (57.64%). No significant differences were noticed for Cu and Zn in terms of apparent absorption, between the groups with/without phytase. The deposits of Cu and Zn in the main organs and serum (from slaughtered

  2. Trace amounts of Cu²⁺ ions influence ROS production and cytotoxicity of ZnO quantum dots.

    Science.gov (United States)

    Moussa, Hatem; Merlin, Christophe; Dezanet, Clément; Balan, Lavinia; Medjahdi, Ghouti; Ben-Attia, Mossadok; Schneider, Raphaël

    2016-03-05

    3-Aminopropyltrimethoxysilane (APTMS) was used as ligand to prepare ZnO@APTMS, Cu(2+)-doped ZnO (ZnO:Cu@APTMS) and ZnO quantum dots (QDs) with chemisorbed Cu(2+) ions at their surface (ZnO@APTMS/Cu). The dots have a diameter of ca. 5 nm and their crystalline and phase purities and composition were established by X-ray diffraction, transmission electron microscopy, UV-visible and fluorescence spectroscopies and by X-ray photoelectron spectroscopy. The effect of Cu(2+) location on the ability of the QDs to generate reactive oxygen species (ROS) under light irradiation was investigated. Results obtained demonstrate that all dots are able to produce ROS (OH, O2(-), H2O2 and (1)O2) and that ZnO@APTMS/Cu QDs generate more OH and O2(-) radicals and H2O2 than ZnO@APTMS and ZnO:Cu@APTMS QDs probably via mechanisms associating photo-induced charge carriers and Fenton reactions. In cytotoxicity experiments conducted in the dark or under light exposure, ZnO@APTMS/Cu QDs appeared slightly more deleterious to Escherichia coli cells than the two other QDs, therefore pointing out the importance of the presence of Cu(2+) ions at the periphery of the nanocrystals. On the other hand, with the lack of photo-induced toxicity, it can be inferred that ROS production cannot explain the cytotoxicity associated to the QDs. Our study demonstrates that both the production of ROS from ZnO QDs and their toxicity may be enhanced by chemisorbed Cu(2+) ions, which could be useful for medical or photocatalytic applications.

  3. Antiproliferative effects of ZnO, ZnO-MTCP, and ZnO-CuMTCP nanoparticles with safe intensity UV and X-ray irradiation.

    Science.gov (United States)

    Sadjadpour, Susan; Safarian, Shahrokh; Zargar, Seyed Jalal; Sheibani, Nader

    2016-01-01

    In photodynamic therapy (PDT) of cancer both the light and the photosensitizing agent are normally harmless, but in combination they could result in selective tumor killing. Zinc oxide nanoparticles were synthesized and coated with the amino acid cysteine to provide an adequate arm for conjugation with porphyrin photosensitizers (meso-tetra (4-carboxyphenyl) porphyrin [MTCP] and CuMTCP). Porphyrin-conjugated nanoparticles were characterized by TEM, FTIR, and UV-vis, and fluorescence spectrophotometry. The 3-[4, 5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay was used to measure cell viability in the presence or absence of porphyrin conjugates following UV and X-ray irradiation. The uptake of the porphyrin-conjugated ZnO nanoparticles by cells was detected using fluorescence microscopy. Our results indicated that the survival of T-47D cells was significantly compromised in the presence of ZnO-MTCP-conjugated nanostructures with UV light exposure. Exhibition of cytotoxic activity of ZnO-MTCP for human prostate cancer (Du145) cells occurred at a higher concentration, indicating the more resistant nature of these tumor cells. ZnO-CuMTCP showed milder cytotoxic effects in human breast cancer (T-47D) and no cytotoxic effects in Du145 with UV light exposure, consistent with its lower cytotoxic potency as well as cellular uptake. Surprisingly, none of the ZnO-porphyrin conjugates exhibited cytotoxic effects with X-ray irradiation, whereas ZnO alone exerted cytotoxicity. Thus, ZnO and ZnO-porphyrin nanoparticles with UV or X-ray irradiation may provide a suitable treatment option for various cancers.

  4. Responses of antioxidant defenses to Cu and Zn stress in two aquatic fungi.

    Science.gov (United States)

    Azevedo, Maria-Manuel; Carvalho, Agostinho; Pascoal, Cláudia; Rodrigues, Fernando; Cássio, Fernanda

    2007-05-15

    Aquatic hyphomycetes are fungi that play a key role in plant litter decomposition in streams. Even though these fungi occur in metal-polluted streams, the mechanisms underlying their tolerance to metals are poorly documented. We addressed the effects of Zn and Cu in Varicosporium elodeae and Heliscus submersus by examining metal adsorption to cell walls, plasma membrane integrity and production of reactive oxygen species at metal concentrations inhibiting biomass production in 50% or 80%. The activity of the enzymes catalase, superoxide dismutase and glucose-6-phosphate dehydrogenase was measured to elucidate their role in coping with oxidative stress induced by metals at short- (14 h) and long- (8 days) term exposure. Results show that V. elodeae was more susceptible to the toxic effects induced by Cu and Zn than H. submersus, as indicated by more extensive inhibition of biomass production. Both metals, particularly Cu, induced oxidative stress in the two fungal species, as shown by the noticeable recovery of biomass production in the presence of an antioxidant agent. In both fungi, Cu induced a more severe disruption of plasma membrane integrity than Zn. Our studies on antioxidant defenses showed that catalase had a greater role alleviating stress induced by Zn and Cu than superoxide dismutase. Chronic metal stress also stimulated the production of NADPH, via the pentose phosphate pathway by increasing the activity of glucose-6-phosphate dehydrogenase. Our results suggest that the tolerance of aquatic hyphomycetes to Cu and Zn is associated with the ability of these fungi to initiate an efficient antioxidant defense system.

  5. Morphology, electrical, and optical properties of heavily doped ZnTe:Cu thin films

    Energy Technology Data Exchange (ETDEWEB)

    El Akkad, Fikry [Physics Department, College of Science, Kuwait University, P.O. Box 5969, Safat 13060 (Kuwait); Abdulraheem, Yaser [Department of Electrical Engineering, College of Engineering and Petroleum, Kuwait University, Safat 13060 Kuwait (Kuwait)

    2013-11-14

    We report on a study of the physical properties of ZnTe:Cu films with Cu content up to ∼12 at. % prepared using rf magnetron sputtering. The composition and lateral homogeneities are studied using X-ray photoelectron spectroscopy (XPS). Atomic force microscopy measurements on films deposited at different substrate temperatures (up to 325 °C) yielded activation energy of 12 kJ/mole for the grains growth. The results of XPS and electrical and optical measurements provide evidence for the formation of the ternary zinc copper telluride alloy in films containing Cu concentration above ∼4 at. %. The XPS results suggest that copper is incorporated in the alloy with oxidation state Cu{sup 1+} so that the alloy formula can be written Zn{sub 1−y}Cu{sub y} Te with y = 2−x, where x is a parameter measuring the stoichiometry in the Cu site. The formation of this alloy causes appreciable shift in the binding energies of the XPS peaks besides an IR shift in the energy band gap. Detailed analysis of the optical absorption data revealed the presence of two additional transitions, besides the band gap one, originating from the Γ{sub 8} and Γ{sub 7} (spin-orbit) valence bands to a donor level at ∼0.34 eV below the Γ{sub 6} conduction band. This interpretation yields a value for the valence band splitting energy Δ≅ 0.87 eV independent of copper concentration. On the other hand, the mechanism of formation of the alloy is tentatively explained in terms of a point defect reaction in which substitutional Cu defect Cu{sub Zn} is also created. Assuming that substitutional Cu is the dominant acceptor in the Zn rich alloy as in ZnTe, its formation energy was determined to be 1.7 eV close to the theoretical value (1.41 eV) in ZnTe.

  6. Toxicity Evaluation of a New Zn-Doped CuO Nanocomposite With Highly Effective Antibacterial Properties.

    Science.gov (United States)

    Mantecca, Paride; Moschini, Elisa; Bonfanti, Patrizia; Fascio, Umberto; Perelshtein, Ilana; Lipovsky, Anat; Chirico, Giuseppe; Bacchetta, Renato; Del Giacco, Luca; Colombo, Anita; Gedanken, Aharon

    2015-07-01

    The increased resistances to conventional antibiotics determine a strong need for new antibacterials, and specific syntheses at the nanoscale promise to be helpful in this field. A novel Zinc-doped Copper oxide nanocomposite (nZn-CuO) has been recently sonochemically synthesized and successfully tested also against multi-drug resistant bacteria. After synthesis and characterization of the physicochemical properties, the new nZn-CuO is here evaluated by the Frog Embyo Teratogenesis Assay-Xenopus test for its toxicological potential and this compared with that of nCuO and nZnO synthesized under the same conditions. No lethal effects are observed, while malformations and growth retardation slightly increase after nZn-CuO exposure. Nevertheless, these effects are smaller than those of nZnO. NP uptake by embryo tissues increase significantly with increasing NP concentrations, while no significant accumulation and adverse effects are seen after exposure to soluble Cu(2+) and Zn(2+) at the concentrations dissolved from the NPs. Key oxidative response genes are upregulated by nZn-CuO, as well as by nCuO and nZnO, suggesting the common mechanism of action. Considering the enhanced biocidal activity shown by the nanocomposite, together with the results presented in this study, we can affirm that the doping of the metal oxide nanoparticles should be considered a useful tool to engineer a safer nano-antibacterial.

  7. Zn incorporation and (CuIn)1-xZn2xSe2 thin film formation during the selenization of evaporated Cu and In precursors on Al:ZnO coated glass substrates

    Science.gov (United States)

    Guillén, C.; Herrero, J.

    2011-11-01

    CuInSe2 thin films with typical 1.0 eV gap energy and tetragonal chalcopyrite structure have been obtained on soda-lime glass substrates by the reaction of sequentially evaporated Cu and In layers with elemental selenium vapor, at 500 °C in flowing Ar. When analogous deposition and reaction processes were performed on Al:ZnO coated glasses, some increment in the band gap energy and diminution in the crystalline interplanar spacings have been detected for the resulting films with an extent that depends on the Cu/In atomic ratio of the evaporated precursor layers. This fact has been related to Zn incorporation into the selenized film, with quaternary (CuIn)1-xZn2xSe2 compound formation that is influenced by the presence of copper selenide phases during the reaction process. Such deductions are supported by the optical, structural and compositional characterizations that have been performed comparatively on samples prepared by selenization of evaporated metallic precursors with two different Cu/In ratios (0.9 and 1.1) on bare and Al:ZnO coated glass substrates.

  8. First-principles study of defect formation in the photovoltaic semiconductor Cu2SnS3 for comparison with Cu2ZnSnS4 and CuInSe2

    Science.gov (United States)

    Nishihara, Hironori; Maeda, Tsuyoshi; Shigemi, Akio; Wada, Takahiro

    2016-04-01

    The formation energies of neutral Cu, Sn, and S vacancies in monoclinic Cu2SnS3 were calculated by first-principles pseudopotential calculations using plane-wave basis functions in typical points in a schematic ternary phase diagram of a Cu-Sn-S system. The formation energy of a Cu atom vacancy in Cu2SnS3 under the Cu-poor condition has been calculated to be 0.23 eV, which is considerably smaller than those of Sn and S vacancies in Cu2SnS3. The results have been compared with those in Cu2SnZnS4 and CuInSe2 calculated with the same version of program code. The formation energy of a Cu atom vacancy in Cu2SnS3 under the Cu-poor condition is smaller than those for Cu2SnZnS4 (0.40 eV) and CuInSe2 (0.50 eV). The results indicate that Cu vacancies are easily formed in Cu2SnS3 under the Cu-poor condition as is the case with Cu2ZnSnS4 and CuInSe2. In this respect, Cu2SnS3 has the appropriate character of a light-absorbing material for thin-film solar cells, as is the case with Cu2ZnSnS4 and CuInSe2.

  9. Extremely High Phosphate Sorption Capacity in Cu-Pb-Zn Mine Tailings.

    Science.gov (United States)

    Huang, Longbin; Li, Xiaofang; Nguyen, Tuan A H

    2015-01-01

    Elevated inorganic phosphate (Pi) concentrations in pore water of amended tailings under direct revegetation may cause toxicity in some native woody species but not native forbs or herb species, all of which are key constituents in target native plant communities for phytostabilizing base metal mine tailings. As a result, Pi sorption capacity has been quantified by a conventional batch procedure in three types of base metal mine tailings sampled from two copper (Cu)-lead (Pb)-zinc (Zn) mines, as the basis for Pi-fertiliser addition. It was found that the Pi-sorption capacity in the tailings and local soil was extremely high, far higher than highly weathered agricultural soils in literature, but similar to those of volcanic ash soils. The Langmuir P-sorption maximum was up to 7.72, 4.12, 4.02 and 3.62 mg P g-1 tailings, in the fresh tailings of mixed Cu-Pb-Zn streams (MIMTD7), the weathered tailings of mixed Cu-Pb-Zn streams (MIMTD5), EHM-TD (fresh Cu-stream, high magnetite content) and local soil (weathered shale and schist), respectively. Physicochemical factors highly correlated with the high Pi-sorption in the tailings were fine particle distribution, oxalate and dithionite-citrate-bicarbonate extractable Fe (FeO and Fed), oxalate-extractable Al and Mn, and the levels of soluble Cd and Zn, and total S and Fe. Large amounts of amorphous Fe oxides and oxyhydroxides may have been formed from the oxidation of pyritic materials and redox cycles of Fe-minerals (such as pyrite (FeS2), ankerite (Ca(Fe Mg)(CO3)2 and siderite (FeCO3), as indicated by the extractable FeO values. The likely formation of sparingly soluble Zn-phosphate in the Pb-Zn tailings containing high levels of Zn (from sphalerite ((Zn,Fe)S, ZnS, (Zn,Cd)S)) may substantially lower soluble Zn levels in the tailings through high rates of Pi-fertiliser addition. As a result, the possibility of P-toxicity in native plant species caused by the addition of soluble phosphate fertilizers would be minimal.

  10. Fusion and characterization of an alloy Cu-Zn-Al-Ni of nuclear interest; Fusion y caracterizacion de una aleacion Cu-Zn-Al-Ni de interes nuclear

    Energy Technology Data Exchange (ETDEWEB)

    Santana M, J.S

    2003-07-01

    The present work is the result of the study of a non ferrous quatenary alloy of Cu-Zn-Al-Ni (Foundry 3), it was chosen of a series of alloys to obtain so much information of its microstructural properties like mechanical, evaluating them and comparing them with the previously obtained ternary alloys of Cu-AI-Ni (Foundry 1) and Cu-Zn-AI (Foundry 2) identified as alloys of memory effect and superalloys. These were carried out starting from the foundry of their pure elements of Cu, Zn, Al, Ni. When physically having the ingot of each alloy, different techniques were used for their characterization. The used techniques were through the metallographic analysis, by scanning electron microscopy (SEM), X-ray dispersive energy spectroscopy (EDS), X-ray diffraction (XRD), mechanical essays and Rockwell hardness. The non ferrous quaternary alloy Cu-Zn-AI-Ni by means of the metallographic analysis didn't show significant differences in their three sections (superficial, longitudinal and transverse) since result an homogeneous alloy at the same that the both ternaries. The grain size of the quaternary alloy is the finest while the ternary alloy of Cu-AI-Ni is the one that obtained the biggest grain size. Through MEB together with the analysis by EDS and the mapping of the elements that constitute each alloy, show that the three foundries were alloyed, moreover the presence of aggregates was also observed in the Foundries 2 and 3. These results by means of the analysis of XRD corroborate that these alloys have more of two elements. Relating the microstructural properties with those mechanical show us that as minor was the grain size, better they were his mechanical properties, in this case that of the quaternary alloy. With regard to the test of Rockwell hardness the Foundry 1 were the softest with the temper treatment, while that the Foundries 2 and 3 were the hardest with this same treatment, being still harder the Foundry 2 but with very little difference, for what great

  11. Copper doping of ZnO crystals by transmutation of {sup 64}Zn to {sup 65}Cu: An electron paramagnetic resonance and gamma spectroscopy study

    Energy Technology Data Exchange (ETDEWEB)

    Recker, M. C.; McClory, J. W., E-mail: John.McClory@afit.edu; Holston, M. S.; Golden, E. M.; Giles, N. C. [Department of Engineering Physics, Air Force Institute of Technology, Wright-Patterson Air Force Base, Ohio 45433 (United States); Halliburton, L. E. [Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506 (United States)

    2014-06-28

    Transmutation of {sup 64}Zn to {sup 65}Cu has been observed in a ZnO crystal irradiated with neutrons. The crystal was characterized with electron paramagnetic resonance (EPR) before and after the irradiation and with gamma spectroscopy after the irradiation. Major features in the gamma spectrum of the neutron-irradiated crystal included the primary 1115.5 keV gamma ray from the {sup 65}Zn decay and the positron annihilation peak at 511 keV. Their presence confirmed the successful transmutation of {sup 64}Zn nuclei to {sup 65}Cu. Additional direct evidence for transmutation was obtained from the EPR of Cu{sup 2+} ions (where {sup 63}Cu and {sup 65}Cu hyperfine lines are easily resolved). A spectrum from isolated Cu{sup 2+} (3d{sup 9}) ions acquired after the neutron irradiation showed only hyperfine lines from {sup 65}Cu nuclei. The absence of {sup 63}Cu lines in this Cu{sup 2+} spectrum left no doubt that the observed {sup 65}Cu signals were due to transmuted {sup 65}Cu nuclei created as a result of the neutron irradiation. Small concentrations of copper, in the form of Cu{sup +}-H complexes, were inadvertently present in our as-grown ZnO crystal. These Cu{sup +}-H complexes are not affected by the neutron irradiation, but they dissociate when a crystal is heated to 900 °C. This behavior allowed EPR to distinguish between the copper initially in the crystal and the copper subsequently produced by the neutron irradiation. In addition to transmutation, a second major effect of the neutron irradiation was the formation of zinc and oxygen vacancies by displacement. These vacancies were observed with EPR.

  12. Phosphinate stabilised ZnO and Cu colloidal nanocatalysts for CO2 hydrogenation to methanol.

    Science.gov (United States)

    Brown, N J; Weiner, J; Hellgardt, K; Shaffer, M S P; Williams, C K

    2013-12-07

    Colloidal solutions of ZnO-Cu nanoparticles can be used as catalysts for the reduction of carbon dioxide with hydrogen. The use of phosphinate ligands for the synthesis of the nanoparticles from organometallic precursors improves the reductive stability and catalytic activity of the system.

  13. New influence factor inducing difficulty in selective flotation separation of Cu-Zn mixed sulfide minerals

    Science.gov (United States)

    Deng, Jiu-shuai; Mao, Ying-bo; Wen, Shu-ming; Liu, Jian; Xian, Yong-jun; Feng, Qi-cheng

    2015-02-01

    Selective flotation separation of Cu-Zn mixed sulfides has been proven to be difficult. Thus far, researchers have found no satisfactory way to separate Cu-Zn mixed sulfides by selective flotation, mainly because of the complex surface and interface interaction mechanisms in the flotation solution. Undesired activation occurs between copper ions and the sphalerite surfaces. In addition to recycled water and mineral dissolution, ancient fluids in the minerals are observed to be a new source of metal ions. In this study, significant amounts of ancient fluids were found to exist in Cu-Zn sulfide and gangue minerals, mostly as gas-liquid fluid inclusions. The concentration of copper ions released from the ancient fluids reached 1.02 × 10-6 mol/L, whereas, in the cases of sphalerite and quartz, this concentration was 0.62 × 10-6 mol/L and 0.44 × 10-6 mol/L, respectively. As a result, the ancient fluid is a significant source of copper ions compared to mineral dissolution under the same experimental conditions, which promotes the unwanted activation of sphalerite. Therefore, the ancient fluid is considered to be a new factor that affects the selective flotation separation of Cu-Zn mixed sulfide ores.

  14. Cu,Zn Superoxide Dismutase Maturation and Activity Are Regulated by COMMD1

    NARCIS (Netherlands)

    Vonk, Willianne I. M.; Wijmenga, Cisca; Berger, Ruud; van de Sluis, Bart; Klomp, Leo W. J.

    2010-01-01

    The maturation and activation of the anti-oxidant Cu, Zn superoxide dismutase (SOD1) are highly regulated processes that require several post-translational modifications. The maturation of SOD1 is initiated by incorporation of zinc and copper ions followed by disulfide oxidation leading to the forma

  15. Wetting and Interfacial Chemistry of Sn-Zn-Ga Alloys with Cu Substrate

    Science.gov (United States)

    Gancarz, Tomasz; Fima, Przemyslaw

    2016-08-01

    Wetting of Cu pads by Sn-Zn eutectic-based alloys with 0.1, 0.2, 0.5, and 1.0 wt.% of Ga was studied using the sessile drop method in the presence of ALU33® flux. Wetting tests were performed at 250 °C after 60, 180, 480, 900, 1800, and 3600 s of contact, and at 230, 280, 320 °C for a contact time of 480 s. After cleaning the flux residue from solidified samples, the spreadability of Sn-Zn-Ga on Cu was determined in accordance with ISO 9455-10:2013-03. Selected, solidified solder-pad couples were cross-sectioned and subjected to scanning electron microscopy with energy dispersive spectroscopy and x-ray diffraction study of the interfacial microstructure. Growth of the intermetallic Cu5Zn8 and CuZn4 phase layers was studied at the solder-pad interface. Samples after spreading test at 250 °C for 60 s were subjected to aging for 1, 10, and 30 days at 170 °C.

  16. Effect of solution heat treatment time on a rheocast Al-Zn-Mg-Cu alloy

    CSIR Research Space (South Africa)

    Mazibuko, NE

    2011-06-01

    Full Text Available During rheo-high pressure die casting (R-HPDC) of Al-Zn-Mg-Cu alloys a coarse eutectic phase is formed. This eutectic phase is difficult to take into solution because of its size and it would require longer solution heat treatment times...

  17. Epitaxial Cu{sub 2}ZnSnSe{sub 4} thin films and devices

    Energy Technology Data Exchange (ETDEWEB)

    Redinger, Alex [Laboratory for Photovoltaics, Physics and Materials Science Research Unit, University of Luxembourg, 41, rue du Brill, L-4422 Belvaux (Luxembourg); Groiss, Heiko [Karlsruhe Institute of Technology, Laboratory for Electron Microscopy, Engesserstr. 7, D-76131 Karlsruhe (Germany); Sendler, Jan; Djemour, Rabie; Regesch, David [Laboratory for Photovoltaics, Physics and Materials Science Research Unit, University of Luxembourg, 41, rue du Brill, L-4422 Belvaux (Luxembourg); Gerthsen, Dagmar [Karlsruhe Institute of Technology, Laboratory for Electron Microscopy, Engesserstr. 7, D-76131 Karlsruhe (Germany); Siebentritt, Susanne, E-mail: susanne.siebentritt@uni.lu [Laboratory for Photovoltaics, Physics and Materials Science Research Unit, University of Luxembourg, 41, rue du Brill, L-4422 Belvaux (Luxembourg)

    2015-05-01

    Epitaxial Cu{sub 2}ZnSnSe{sub 4} (CZTSe) thin films have been grown via high temperature coevaporation on GaAs(001). Electron backscattering diffraction confirms epitaxy in a wide compositional range. Different secondary phases are present in the epitaxial layer. The main secondary phases are Cu{sub 2}SnSe{sub 3} and ZnSe which grow epitaxially on top of the CZTSe. Transmission electron microscopy measurements show that the epitaxial CZTSe grows predominantly parallel to the c-direction. Epitaxial CZTSe solar cells with a maximum power conversion efficiency of 2.1%, an open-circuit voltage of 223 mV and a current density of 16 mA/cm{sup 2} are presented. - Highlights: • Epitaxial Cu{sub 2}ZnSnSe{sub 4} has been grown on GaAs(001). • Material includes epitaxial Cu{sub 2}SnSe{sub 3} and ZnSe secondary phases. • TEM investigations show that the orientation is mainly parallel to the c-direction. • Epitaxial solar cells have been fabricated.

  18. ZnO-(Cu/Ag)TCNQ heterostructure network over flexible platform for enhanced cold cathode application

    Science.gov (United States)

    Pal, Shreyasi; Maiti, Soumen; Narayan Maiti, Uday; Chattopadhyay, Kalyan Kumar

    2016-07-01

    Multistage field emitters consisting of organic/inorganic hybrid nanostructures with branched geometry are designed via a two-step protocol: a simple wet chemical method followed by a vapor-solid-phase technique. (Cu/Ag)TCNQ (copper/silver-7,7,8,8-tetracyanoquinodimethane) nanowires (NWs) were grown hierarchically on zinc oxide (ZnO) nanorods (NRs) to form ZnO-(Cu/Ag)TCNQ heterostructure assemblies. By monitoring the metallic Cu and Ag coating thickness on ZnO NRs, precise control over the morphology and orientations of the secondary organic NWs is achieved. In-depth analysis of electron field emission (FE) behavior of the ZnO-(Cu/Ag)TCNQ-based hierarchy suggests highest emission performance with low turn-on as well as threshold fields of 1.15 and 3.75 V μm-1 respectively from the morphology-optimized hierarchy. Beneficial orientation of the branched organic NWs ensures sequential electric field enhancement in the consecutive stem and branches whereas its low work function eases electron emission; these aspects combined together render an overall enhancement in the emission behavior of the hybrid system. As compared to individual building units, the heterostructures show improved field electron emission. Additionally, successful construction of this novel hybrid over a fabric platform displays great potential in opening up new pathways in the highly-anticipated field of flexible electronics.

  19. A study of quenched CuZnAl Alloy by positron

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Cu-23at.%Zn-11at.% Al alloyhas been studied bypositron annihilation technique.It is shown that the defects in the alloy induced by quenching from the temperature above α-transformation are basically monovacancies, instead of other forms of defects.

  20. Magnetic properties of the Ni-Cu-Zn system doped with magnesium oxide

    Science.gov (United States)

    Hemeda, O. M.; Tawfik, A.; Hemeda, D. M.; Elsheekh, A. M.

    2015-09-01

    A series of ferrite samples, Ni0.1Cu0.2MgxZn0.7-x Fe2O4, (x=0.00, 0.15, 0.25, 0.35, 0.45, 0.55 and 0.70) has been prepared by the standard ceramic technique, sintered at 1200 °C for 2 h, and their crystalline structures were investigated by using X-ray diffraction. The IR spectra and the ESR spectra analysis have been studied. DC electrical resistivity, thermoelectric power, charge carriers concentration and charge carrier mobility have been calculated at different temperatures. The value of dc electrical resistivity reach minimum at x=0.35 and above this value the electrical resistivity start to increase. It is noticed that thermoelectric power α for the "Ni-Cu-Zn" system exhibits a positive sign indicating the majority carriers are holes without excluding the presence of electrons. Saturation magnetization Ms for the "Ni-Cu-Zn" system was calculated from M-H loop. It is noted that Ms decreases with Mg content up to x=0.55 and rapidly decrease above x>0.55 for the "Ni-Cu-Zn" system.

  1. Isolation and characterization of Cu,Zn superoxide dismutase of the shark Prionace glauca.

    Science.gov (United States)

    Galtieri, A; Natoli, G; Lania, A; Calabrese, L

    1986-01-01

    A Cu,Zn superoxide dismutase was purified for the first time from an elasmobranch species (Prionace glauca) and showed the following differences with respect to other animal superoxide dismutases. The enzyme displays a low isoelectric point. The enzyme activity is unusually independent of ionic strength. The isolated enzyme has 30% of its copper in the reduced state.

  2. What is the band alignment of Cu2ZnSn(S,Se)4 solar cells?

    DEFF Research Database (Denmark)

    Crovetto, Andrea; Hansen, Ole

    2017-01-01

    The band alignment at the Cu2ZnSn(S,Se)4/CdS solar cell heterojunction is a controversial issue, as different measurements and calculations point to substantially different conduction band offsets (CBO). As the actual value of the CBO has profound implications on solar cell performance, the aim...... measurement approaches. Interestingly, a rough correlation can be established between the CBO measured at the Cu2ZnSnS4/CdS interface by different groups and their corresponding solar cell efficiency: lower-efficiency cells often have a large "cliff-like" offset, whereas most high-efficiency cells have...... a "spike-like" or nearly flat offset. Control of interdiffusion can be a powerful way to engineer the optimal band alignment in Cu2ZnSnS4/CdS solar cells, but it can be detrimental in Cu2ZnSnSe4/CdS solar cells, as it may increase the CBO above the optimal range for maximum efficiency....

  3. Heterojunction characteristics of ZnO and CuO substrates formed by direct bonding

    Energy Technology Data Exchange (ETDEWEB)

    Abe, Hiroshi; Fujishima, Masahide; Komiyama, Takao; Chonan, Yasunori; Yamaguchi, Hiroyuki; Aoyama, Takashi [Department of Electronics and Information Systems, Akita Prefectural University, Yuri-honjo, Akita 015-0055 (Japan)

    2012-06-15

    The n-ZnO/p-CuO heterojunction characteristics have been investigated by direct bonding of ZnO and CuO substrates at room temperatures, and by post-annealing at 800 C. The ZnO substrate was fabricated by mixing of ZnO and Al{sub 2}O{sub 3} (2%) powders, pressing at 50 MPa, and sintering at 1400 C while the CuO substrate was fabricated by mixing of CuO and Li{sub 2}CO{sub 3} (1%) powders, pressing at 300 MPa, and sintering at 700 C. Rectifying behaviour with an ideality factor of 126 was observed after bonding of these substrates. Post-annealing of the heterojunction, however, significantly increased both the forward and the reverse currents, and the rectifying behaviour was lost. Symmetrical I-V curves with threshold voltages of about {+-} 1 V were observed and this degradation could be explained by impurity (Al and Li) segregation at the junction interface. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. Assessing the Levels of Pb, Cd, Zn and Cu in Biscuits and Home ...

    African Journals Online (AJOL)

    ADOWIE PERE

    The mean levels of Zn, Cu, Pb and Cd found in plantain chips obtained from the University ... the upper limits of the range specified by the World Health Organization, the consumption of .... 0.52 mg/kg) in potato chips sampled from the second.

  5. Detection of esophageal cancer cell by photoelectrochemical Cu2O/ZnO biosensor (Conference Presentation)

    Science.gov (United States)

    Hsu, Chao-Hsin; Chu, Cheng-Hsun; Chen, Weichung; Wu, I.-Chen; Wu, Ming Tsang; Kuo, Chie-Tong; Tsiang, Raymond Chien-Chao; Wang, Hsiang-Chen

    2016-03-01

    We have demonstrated a Cu2O/ZnO nanorods (NRs) array p-n heterostructures photoelectrochemical biosensor. The electrodeposition of Cu2O at pH 12 acquired the preferably (111) lattice planes, resulting in the largest interfacial electric field between Cu2O and ZnO, which finally led to the highest separation efficiency of photogenerated charge carriers. High verticality ZnO nanorods by seed layer and thermal annealing assist the hydrothermal growth. The optimized Cu2O/ZnO NRs array p-n heterostructures exhibited enhanced PEC performance, such as elevated photocurrent and photoconversion efficiency, as well as excellent sensing performance for the sensitive detection of four strains of different races and different degree of cancer cell which made the device self-powered. We got spectral response characteristics and operating wavelength range of biosensor, and to verify the biological characteristics of cancer cells wafer react with different stages of cancer characterized by a cancer measured reaction experiment.

  6. Precipitation of CuS and ZnS in a bubble column reactor

    NARCIS (Netherlands)

    Al-Tarazi, M.; Heesink, A. Bert M.; Versteeg, G. F.; Azzam, M. O. J.; Azzam, K.

    2005-01-01

    This work presents an experimental study into the precipitation of CuS and ZnS in a semibatch-wise operated bubble column. First the applied bubble column was characterized with respect to mass transfer phenomena. The influences of ionic strength and superficial gas velocity on volumetric mass trans

  7. Heavy metal (Zn and Cu) complexation and molecular size distribution in wastewater treatment plant effluent.

    Science.gov (United States)

    Chaminda, G G T; Nakajima, F; Furumai, H

    2008-01-01

    The size distributions of zinc and copper species in the effluent of a wastewater treatment plant were determined by a combination of ultrafiltration and chelating disk cartridge fractionation. The results showed that 75-87% of total Zn and 84-86% of total Cu were strongly complexed or particle-bound in the final effluents. It was also found that the major part of Cu was bound to ligands in the < 500 Da fraction while the trend for Zn was not so clear and exhibited significant seasonal variability. Labile Cu and Zn were detected not only in the smallest fraction (< 500 Da) but also in the larger fractions. It meant that the labile species in the effluent were not equivalent to free metal ions. Conditional stability constants and ligand concentrations were also determined from the measured metal concentrations by square wave anodic stripping voltammetry. Existence of two types of ligand for each metal was inferred from the experimental data. Conditional stability constant obtained for the stronger type Ligand of Zn was higher than that of Cu, although the estimated Ligand concentrations were almost similar.

  8. Nanoparticles from Cu-Zn-Al shape memory alloys physically synthesized by ion milling deposition

    Directory of Open Access Journals (Sweden)

    Luis Alberto López Pavón

    2012-06-01

    Full Text Available In this research, an ion milling equipment was used to elaborate nanoparticles from Cu-Zn-Al alloys with shape memory effect. Two different compositions were used, target A: 75.22Cu-17.12Zn-7.66Al at % with an Ms of -9 °C and target B: 76.18Cu-15.84Zn-7.98Al with an Ms of 20 °C. Nanoparticles were characterized by High Resolution Transmission Electron Microscopy, Electron Diffraction and Energy Dispersive X-ray Spectroscopy. The obtained nanoparticles showed a small dispersion, with a size range of 3.2-3.5 nm. Their crystal structure is in good agreement with the bulk martensitic structure of the targets. In this sense, results on morphology, composition and crystal structure have indicated that it is possible to produce nanoparticles of CuZnAl shape memory alloys with martensitic structure in a single process using Ion Milling.

  9. Interfacial reactions of Sn-Ag-Cu solders modified by minor Zn alloying addition

    Science.gov (United States)

    Kang, Sung K.; Leonard, Donovan; Shih, Da-Yuan; Gignac, Lynne; Henderson, D. W.; Cho, Sungil; Yu, Jin

    2006-03-01

    The near-ternary eutectic Sn-Ag-Cu alloys have been identified as leading Pb-free solder candidates to replace Pb-bearing solders in microelectronic applications. However, recent investigations on the processing behavior and solder joints reliability assessment have revealed several potential reliability risk factors associated with the alloy system. The formation of large Ag3Sn plates in Sn-Ag-Cu joints, especially when solidified in a relatively slow cooling rate, is one issue of concern. The implications of large Ag3Sn plates on solder joint performance and several methods to control them have been discussed in previous studies. The minor Zn addition was found to be effective in reducing the amount of undercooling required for tin solidification and thereby to suppress the formation of large Ag3Sn plates. The Zn addition also caused the changes in the bulk microstructure as well as the interfacial reaction. In this paper, an in-depth characterization of the interfacial reaction of Zn-added Sn-Ag-Cu solders on Cu and Au/Ni(P) surface finishes is reported. The effects of a Zn addition on modification of the interfacial IMCs and their growth kinetics are also discussed.

  10. Synthesis of ZnO-CuO/MCM-48 photocatalyst for the degradation of organic pollutions.

    Science.gov (United States)

    Duan, Yongzheng; Shen, Yulian

    2017-07-01

    The photocatalytic properties of ZnO-CuO catalysts supported on siliceous MCM-48 (Mobil Composition of Matter No. 48) for the degradation of organic pollutions such as methylene blue and salicylic acid under UV light irradiation were investigated. These catalysts were prepared by impregnation of MCM-48 with a mixed aqueous solution of copper acetate and zinc acetate. X-ray diffraction, N2-physisorption, high resolution transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and photoluminescence were used to characterize these samples. Results from characterizations showed that the addition of ZnO to CuO/MCM-48 could markedly improve the photocatalytic degradation properties. The enhanced photocatalytic behaviors of ZnO-CuO/MCM-48 may be due to the formation of p-n heterojunctions between ZnO and CuO, resulting in the effective separation of photogenerated electron-hole pairs. Moreover, the photocatalysts were easily recovered and reused for five cycles without considerable loss of activity.

  11. Electrodialytic removal of Cu, Zn, Pb, and Cd from harbor sediment: Influence of changing experimental conditions

    DEFF Research Database (Denmark)

    Nystrøm, Gunvor Marie; Ottosen, Lisbeth M.; Villumsen, Arne

    2005-01-01

    Electrodialytic remediation (EDR) was used to remove Cu, Zn, Pb, and Cd from contaminated harbor sediment. Extraction experiments were made prior to EDR, and the metal desorption was pH dependent but not liquid-to-solid ratio (L/S) dependent. The desorption order was Cd $GRT Zn $GRT Pb $GRT Cu...... for the removal of Cu, Zn, and Pb, probably due to oxidation of the sediments during stirring. Contrary, Cd removal was lower in the wet sediment as compared to the air-dried. The heavy metal removal was influenced by higher current strengths and varying L/S ratios. The highest removal obtained...... was in an experiment with dry sediment (L/S 8) and a 70 mA applied current that lasted 14 days. These experimental conditions were thereafter used to remediate more strongly contaminated sediments. Regardless of the initial heavy metal concentrations in the sediments, 67-87% Cu, 79-98% Cd, 90-97% Zn, and 91-96% Pb...

  12. The major Cu,Zn SOD of the phytopathogen Claviceps purpurea is not essential for pathogenicity

    NARCIS (Netherlands)

    Moore, S; De Vries, OMH; Tudzynski, P

    2002-01-01

    Superoxide dismutase (SOD) activities of the biotrophic pathogen Claviceps purpurea, which causes the ergot disease on a wide range of host grasses, were examined in axenic and pathogenic cultures. Almost all SOD activity in axenic culture originated from a single Cu,Zn SOD; a substantial part of th

  13. Magnetic Properties as Indicators of Cu and Zn Contamination in Soils

    Institute of Scientific and Technical Information of China (English)

    LU Sheng-Gao; BAI Shi-Qiang; FU Li-Xia

    2008-01-01

    Concentrations of copper (Cu) and zinc (Zn) and various magnetic parameters in contaminated urban roadside soils were investigated using chemical analysis and magnetic measurements. The results revealed highly elevated Cu and Zn concentrations as well as magnetic susceptibility in the roadside soils. The mean concentrations of Cu and Zn in these roadside soils were almost twice those in average Chincsc soils, with the mean magnetic susceptibility of the roadside soils reaching about 179×10-8m3 kg-1. This enhanced magnetic susceptibility was attributed to the presence of anthro-pogcnic soft ferrimagnetic particles. A low frequency-dependent susceptibility (2.5%±1.0%) observed in the roadside soils indicated the coarse multidomain (MD) fcrrimagnetic grains to be the dominant contributor to magnetic susceptibility.The Cu and Zn concentration of the soils had highly significant linear correlations with magnetic susceptibility (P≤0.01),anhysterctic remanent magnetization (P≤0.01), and saturation isothermal remanent magnetization (P≤0.01). This suggested that heavy metals were associated with ferrimagnetic particles in soils, which were attributed to input of traffic emissions and industrial activities. Scanning electron microscopy and energy dispersive X-ray spectra of magnetic extracts of the roadside soils further suggested the link between the magnetic signal and concentrations of heavy metals. Thus, the magnetic parameters could provide a proxy measure for the level of heavy metal contamination and could be a potential tool for the detection and mapping of contaminated soils.

  14. Adsorption and sonocatalytic performance of magnetite ZnO/CuO with NGP variation

    Science.gov (United States)

    Taufik, A.; Saleh, R.

    2017-04-01

    A series of Fe3O4/ZnO/CuO/nanographene platelets (Fe3O4/ZnO/CuO/NGP) nanocomposites with various NGP weight percents were studied as catalysts for methylene blue removal under adsorption followed by sonocatalytic process. Weight percents (wt.%) of NGP in the nanocomposites were varied (5, 10, and 15 wt.%). The physicochemical properties of the samples were characterized using X-Ray diffraction (XRD), ultraviolet-visible (UV-VIS) spectroscopy, Brunauer-Emmett-Teller (BET) surface area analysis, and a vibrating sample magnetometer (VSM). The heterogeneous structure of all samples consisted of the cubic spinel structure of Fe3O4, hexagonal wurtzite structure of ZnO, monoclinic structure of CuO, and graphite-like structure of NGP. With increasing NGP weight percent, sample surface area increased from 14 m2/g to 23 m2/g. Adsorption and sonocatalytic activity were examined on degradation of methylene blue in alkaline conditions. The results show that the adsorption ability of samples increased with increasing NGP weight percent. However, in the sonocatalytic process, Fe3O4/ZnO/CuO/NGP with 10 wt.% NGP exhibited the maximum degradation. The effect of addition different radical scavenger was also examined to understand the sonocatalytic mechanism.

  15. Interactions between Zn and Cu in LEC rats, an animal model of Wilson's disease.

    Science.gov (United States)

    Santon, Alessandro; Giannetto, Sabrina; Sturniolo, Giacomo Carlo; Medici, Valentina; D'Incà, Renata; Irato, Paola; Albergoni, Vincenzo

    2002-03-01

    The effect of oral Zn treatment was studied in the liver and kidneys of 26 male Long-Evans Cinnamon (LEC) rats (mutant animals, 5 weeks old) in relation to both the interaction between Zn and Cu and the localisation and concentration of metallothionein (MT). Rats receiving 80 mg zinc acetate daily by gavage and control rats receiving no treatment were killed after 1 or 2 weeks. By immunohistochemical and analytical chemical techniques we revealed that treated rats had higher levels of MT in the hepatic and renal cells compared to untreated ones. Tissue Zn concentrations were significantly higher in treated rats compared to untreated whereas Cu concentrations decreased in the liver and kidneys as indicated by analytical chemical analyses. MT levels also decreased with treatment period. A histochemical procedure, obtained using autofluorescence of Cu-metallothioneins, confirms these findings: after 2 weeks, the signal decreased in both the liver and kidney sections. This gives a greater understanding of the mechanism of Cu metabolism in the two tissues considered. These results suggest that Zn acts both to compete for absorption on the luminal side of the intestinal epithelium and to induce the synthesis of MT.

  16. Scaling behavior of ZnPc thin films grown on CuI interlayers

    Science.gov (United States)

    Lee, Jinho; Jin, Sung-Il; Park, Chan Ryang; Yim, Sanggyu

    2015-01-01

    The growth behavior and consequent surface morphology evolution of zinc phthalocyanine (ZnPc) thin films deposited on a CuI interlayer were studied using atomic force microscopy and height difference correlation function (HDCF) analysis. The planar phthalocyanine thin films grown on non-interacting substrates have previously been reported to show anomalous scaling behavior such as large growth exponents, ß, sometimes larger than 0.5, and small anomaly values, ρ, typically smaller than 0.6. In contrast, ZnPc thin films on a CuI interlayer (CuI/ ZnPc) in this work showed conventional scaling behavior with a ß value of 0.26 ± 0.05 and a ρ value of 0.91. The HDCF analyses and x-ray diffraction results indicate that the expected interdigitated electron donor-acceptor interface was hardly formed for the CuI/ZnPc thin film system due to the lack of surface-parallel crystallites with high step edge barriers.

  17. Microstructure of the Al2O3/Al2O3 Joint Brazed with Cu-Zn-Ti Filler Metal

    Institute of Scientific and Technical Information of China (English)

    Hongyuan FANG; Jianguo YANG; Xiuyu YU

    2001-01-01

    Microstructure and interface reactions of Al2O3 joints brazed by Cu-Zn-Ti alloy were studied by using SEM, EDS and XRD. The effects of brazing temperature and Ti content on interfacial reactions and microstructure were investigated, and the action of adding Zn into brazing alloy was also studied. TiO, Ti3Al and CuTi were formed at the interface of ceramics and the filler metal, while CuTi, Cu3Ti and α-Cu were found in the brazing. The thickness of the reaction layer increased with increasing of brazing temperature, under the same brazing process, the thickness increased with the Ti content.

  18. Enhanced wetting of Cu on ZnO by migration of subsurface oxygen vacancies

    Science.gov (United States)

    Beinik, Igor; Hellström, Matti; Jensen, Thomas N.; Broqvist, Peter; Lauritsen, Jeppe V.

    2015-11-01

    Metal adhesion on metal oxides is strongly controlled by the oxide surface structure and composition, but lack of control over the surface conditions often limits the possibilities to exploit this in opto- and micro-electronics applications and heterogeneous catalysis where nanostructural control is of utmost importance. The Cu/ZnO system is among the most investigated of such systems in model studies, but the presence of subsurface ZnO defects and their important role for adhesion on ZnO have been unappreciated so far. Here we reveal that the surface-directed migration of subsurface defects affects the Cu adhesion on polar ZnO(0001) in the technologically interesting temperature range up to 550 K. This leads to enhanced adhesion and ultimately complete wetting of ZnO(0001) by a Cu overlayer. On the basis of our experimental and computational results we demonstrate a mechanism which implies that defect concentrations in the bulk are an important, and possibly controllable, parameter for the metal-on-oxide growth.

  19. High specific activity ⁶¹Cu via ⁶⁴Zn(p,α)⁶¹Cu reaction at low proton energies.

    Science.gov (United States)

    Thieme, Stefan; Walther, Martin; Preusche, Stephan; Rajander, Johan; Pietzsch, Hans-Jürgen; Lill, Jan-Olof; Kaden, Michael; Solin, Olof; Steinbach, Jörg

    2013-02-01

    The PET radionuclide (61)Cu is accessible through several nuclear reactions. Besides the common production route via (61)Ni(p,n)(61)Cu the (64)Zn(p,α)(61)Cu reaction offers some advantages. Especially the comparatively cheap enriched (64)Zn makes this process economical. For fast product purification and recycling of target material an ion exchange cascade was developed. In addition a separation technique with a copper selective resin was tested. (61)Cu with specific activities up to 1000 GBq/μmol was produced with these methods. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. 低成本Cu-Zn-Al-X弹性材料的研究进展%Research and Development of Low Cost Cu-Zn-Al-X Elastic Alloy

    Institute of Scientific and Technical Information of China (English)

    李杰; 王永如; 戴姣燕; 肖来荣; 李周; 宗亚平

    2012-01-01

    The component, properties, characteristics of processing technique and strengthening mechanism of Cu-Zn-Al-X elastic alloys, as well as the effect of elements (such as Al,Ni,Co) on properties of the alloy, are expounded in detail. Meanwhile, the development and research progress in the field of Cu-Zn-Al-X copper base elastic alloy at home and abroad are introduced. Tendence of Cu-Zn- Al-Co and Cu-Zn-Al-Ni alloy substitute phosphor bronze gradually in future and optimized design of components, development of advanced technology and so on are pointed out.%详细地阐述了各元素(Al、Ni、Co等)对Cu-Zn-Al-X系列材料的作用以及该系列材料的成分类型、性能、制备工艺特点和强化机理.同时,介绍了国内外在该系铜基弹性合金材料方面的研究进展.指出在未来的发展中Cu-Zn-Al-Co与Cu-Zn-Al-Ni系列具有逐渐部分替代锡磷青铜的趋势,成分优化设计、新工艺开发等将会成为重点研究对象.

  1. Visible light photo-degradation of methylene blue over Fe or Cu promoted ZnO nanoparticles.

    Science.gov (United States)

    Mardani, Hamid Reza; Forouzani, Mehdi; Ziari, Mitra; Biparva, Pourya

    2015-04-15

    CuxZn(1-x)O, FexZn(1-x)O (x=0.01) and ZnO nanoparticles were and were characterized by X-ray diffraction, ultraviolet and visible spectroscopy, FTIR spectroscopy and SEM. The photodegradation of an aqueous solution of methylene blue (as an organic pollutant) by nanoparticles with H2O2 (30%) under visible light and the progress of the reaction were monitored by UV-Vis spectroscopy absorption. The photocatalytic oxidation efficiency of all nanoparticles was 100% at the appropriate time. The degradation time was 90 min for FeZnO, 120 min for CuZnO and 210 min for ZnO. This indicates that the photocatalytic activity of the doped nanoparticles was better than that of ZnO alone. ZnO doped with a small amount of Fe or Cu decreased the size of the nanoparticles and the band gap and increased photocatalytic efficiency.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-07-15

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

  3. Directional solidification of Zn-Al-Cu eutectic alloy by the vertical Bridgman method

    Directory of Open Access Journals (Sweden)

    Büyük U.

    2015-01-01

    Full Text Available In the present work, the effect of growth rate and temperature gradient on microstructure and mechanical properties of Zn-7wt.%Al-4wt.%Cu eutectic alloy has been investigated. Alloys prepared under steady-state conditions by vacuumed hot filing furnace. Then, the alloys were directionally solidified upward with different growth rates (V=11.62-230.77 mm/s at a constant temperature gradient (G=7.17 K/mm and with different temperature gradients (G=7.17-11.04 K/mm at a constant growth rate (V=11.62 mm/s by a Bridgman furnace. The microstructures were observed to be lamellae of Zn, Al and broken lamellae CuZn4 phases from quenched samples. The values of eutectic spacing, microhardness and ultimate tensile strength of alloys were measured. The dependency of the microstructure and mechanical properties on growth rate and temperature gradient were investigated using regression analysis.

  4. Low Cycle Mechanical and Fatigue Properties of AlZnMgCu Alloy

    Directory of Open Access Journals (Sweden)

    Pysz S.

    2016-03-01

    Full Text Available The article presents the analysis of properties of the high-strength AlZnMgCu (abbr AlZn aluminium alloy and estimates possibilities of its application for responsible structures with reduced weight as an alternative to iron alloy castings. The aim of the conducted studies was to develop and select the best heat treatment regime for a 7xx casting alloy based on high-strength materials for plastic working from the 7xxx series. For analysis, wrought AlZnMgCu alloy (7075 was selected. Its potential of the estimated as-cast mechanical properties indicates a broad spectrum of possible applications for automotive parts and in the armaments industry. The resulting tensile and fatigue properties support the thesis adopted, while the design works further confirm these assumptions.

  5. Differential tolerance of Agrostis tenuis populations growing at two mine soils to Cu, Zn, and Pb

    Energy Technology Data Exchange (ETDEWEB)

    Karataglis, S.S.

    1980-01-01

    The Cu, Zn and Pb tolerance of Agrostis tenuis Sibth. populations found in the area of two mines in England as well as in uncontaminated areas were studied by determining the effect of these metals on the rooting of tillers. The populations proved tolerant to the particular metals present in high quantities in the soil of their original habitats as compared to the populations collected from uncontaminated soil. The populations of the Trelogan mine were tolerant only to Zn and not to Cu and Pb. On the contrary, the populations in the mine of Parys Mountain were highly tolerant to all these metals. A linear correlation in the index of tolerance between Zn and Pb in both mines was found suggesting the possibility of a physiological association of the tolerance mechanisms to these two elements.

  6. Mechanically driven luminescence in a ZnS:Cu-PDMS composite

    Directory of Open Access Journals (Sweden)

    Kee-Sun Sohn

    2016-10-01

    Full Text Available The conventional mechanoluminescence (ML mechanism of phosphors such as SrAl2O4:Eu and ZnS:Mn is known to utilize carrier trapping at shallow traps followed by stress (or strain-induced detrapping, which leads to activator recombination in association with local piezoelectric fields. However, such a conventional ML mechanism was found to be invalid for the ZnS:Cu-embedded polydimethylsiloxane (PDMS composite, due to the absence of luminescence with a rigid matrix and a negligibly small value of the piezoelectric coefficient (d33 of the composite. An alternative mechanism, namely, the triboelectricity-induced luminescence has been proposed for the mechanically driven luminescence of a ZnS:Cu-PDMS composite.

  7. Adsorption of Cu2+, Zn2+ and Cd2+ on Bacillus subtilis

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A process of biosorption of Cu2+, Zn2+ and Cd2+ on Bacillus subtilis was investigated.The experiments show that the process of biosorption is quite fast. The maximum adsorption was reached after 5 min and hardly changed with time. The experimental data was analyzed using four sorption kinetic models: the pseudo-first-order, the Ritchie second-order, the modified second-order and the Elovich equations, which helped to determine the best-fit equation for the sorption of metal ions onto biomass. The results show that both the Ritchie second-order and modified secondorder equations can fit the experimental data. The Langmuir model is able to accurately describe adsorption of Cu2+ and Zn2+ on B. subtilis. The experimental data points of adsorption Cd2+ and Zn2+ on B. subtilis are described by Freundlich isotherms model.

  8. Abnormal room temperature ferromagnetism in CuO/ZnO nanocomposites via hydrothermal method

    Science.gov (United States)

    Lu, Ping; Zhou, Wei; Li, Ying; Wang, Jianchun; Wu, Ping

    2017-03-01

    CuO/ZnO nanocomposites have been successfully synthesized by a one-step hydrothermal method with different phase ratios. Field emission scanning electron microscopy and transmission electron microscopy results show that the obtained products of nanosheets are composed of small primary particles with an average size of about 20 nm. With the increasing proportion of CuO phase, nanosheets have significant collapse and the amount of small sheets increases obviously. The abnormal room temperature ferromagnetism was discovered at the interface between diamagnetic ZnO and antiferromagnetic CuO, which can be tuned by changing the phase ratios. Optical spectra indicate that the interaction between ZnO and CuO modifies the electronic structure of nanocomposites. XPS results verify the valence change of Cu ions and the presence of oxygen vacancies, which are ultimately responsible for the observed ferromagnetism. The indirect double-exchange model was employed to explain the origin of magnetism. Our study suggests that magnetically functional interfaces exhibit very appealing properties for novel devices.

  9. Deformation-Induced Martensitic Transformation in Cu-Zr-Zn Bulk Metallic Glass Composites

    Directory of Open Access Journals (Sweden)

    Dianyu Wu

    2015-11-01

    Full Text Available The microstructures and mechanical properties of (Cu0.5Zr0.5100−xZnx (x = 0, 1.5, 2.5, 4.5, 7, 10, and 14 at. % bulk metallic glass (BMG composites were studied. CuZr martensitic crystals together with minor B2 CuZr and amorphous phases dominate the microstructures of the as-quenched samples with low Zn additions (x = 0, 1.5, and 2.5 at. %, while B2 CuZr and amorphous phases being accompanied with minor martensitic crystals form at a higher Zn content (x = 4.5, 7, 10, and 14 at. %. The fabricated Cu-Zr-Zn BMG composites exhibit macroscopically appreciable compressive plastic strain and obvious work-hardening due to the formation of multiple shear bands and the deformation-induced martensitic transformation (MT within B2 crystals. The present BMG composites could be a good candidate as high-performance structural materials.

  10. The role of ionic sizes in inducing the cubic to tetragonal distortion in AV2O4 and ACr2O4 (A = Zn, Mg and Cd) compounds

    Science.gov (United States)

    Lal, Sohan; Pandey, Sudhir K.

    2016-11-01

    Cubic to tetragonal distortion in AV2O4 and ACr2O4 (A = Zn, Mg and Cd) compounds have been a contentious issue for last two decades. Different groups have proposed different mechanisms to understand such a distortion in these spinels, which are: (i) spin lattice coupling mechanism known as the spin driven Jahn-Teller (JT) effect, (ii) the strong relativistic spin-orbit coupling, a moderate JT distortion and weak V-V interactions and (iii) the JT effect. Now, in order to know the possible cause for such a distortion, we have avoided these complexities (various interactions among spin, electronic, orbital and lattice degrees of freedom) by carrying out spin unpolarized calculations. The calculated values of bulk moduli for ZnV2O4 (ZnCr2O4), MgV2O4 (MgCr2O4) and CdV2O4 (CdCr2O4) are found to be ˜289 (˜254), ˜244 (˜243) and ˜230 (˜233) GPa, respectively which suggest that CdV2O4 (among vanadates) and CdCr2O4 (among chromates) are more compressible. For vanadates and chromates, the order of calculated values of lattice parameter a are found to CdV2O4 > MgV2O4 > ZnV2O4 and CdCr2O4 > MgCr2O4 > ZnCr2O4, respectively and are consistent with the experimental results. The calculated values of cubic to tetragonal distortion (c/a), with c/a compounds. The present study clearly shows the role of ionic sizes in inducing the cubic to tetragonal distortion in these spinels. However, the discrepancies between the calculated and experimental data for CdV2O4 and CdCr2O4 are expected to improve by considering the above mentioned mechanisms. These mechanisms also appear to be responsible for deciding the other physical properties of these compounds.

  11. Lattice location and stability of implanted Cu in ZnO

    CERN Document Server

    Wahl, Ulrich; Correia, J G; Alves, E; Carvalho-Soares, José

    2004-01-01

    The lattice location of copper in single-crystalline zinc oxide was studied by means of the emission channeling technique. Following 60 keV room-temperature implantation at a fluence of $\\,2.3\\!\\times\\!10^{13}$ cm$\\!^{-2}$, the angular distribution of $\\beta\\!^{-}$-particles emitted by the radioactive isotope $^{67}$Cu was measured by a position-sensitive detector. The $\\beta$ - emission patterns give direct evidence that in the as-implanted state a large fraction of Cu atoms (60--70%) occupy almost ideal substitutional Zn sites with root mean square (rms) displacements of 0.16--0.17 Å. However, following annealing at 600°C and above Cu was found to be located on sites that are characterized by large rms displacements (0.3--0.5 Å) from Zn sites.

  12. Lattice location and stability of implanted Cu in ZnO

    CERN Document Server

    Wahl, U; Correia, J G; Alves, E; Soares, J G

    2004-01-01

    The lattice location of copper in single-crystalline zinc oxide was studied by means of the emission channeling technique. Following 60-keV room-temperature implantation at a fluence of 2.3 $\\times 10^{13}$cm$^{−2}$, the angular distribution of $\\beta^{-}$-particles emitted by the radioactive isotope $^{67}$Cu was measured by a position-sensitive detector. The $\\beta^{-}$-emission patterns give direct evidence that in the as-implanted state a large fraction of Cu atoms (60%–70%) occupy almost ideal substitutional Zn sites with root-mean-square (rms) displacements of 0.16–0.17 Å. However, following annealing at 600°C and above Cu was found to be located on sites that are characterized by large rms displacements (0.3–0.5 Å) from Zn sites.

  13. Positron lifetime evolution during room temperature ageing in Al-Zn-Mg-(Cu)

    Energy Technology Data Exchange (ETDEWEB)

    Ferragut, R.; Moia, F. [LNESS, Department of Physics, Politecnico di Milano, Como (Italy); Liddicoat, P.; Ringer, S.P. [Australian Key Centre for Microscopy and Microanalysis, ARC Centre of Excellence for Design in Light Metals, University of Sydney, NSW (Australia); Dupasquier, A.

    2009-11-15

    The effect on the formation of vacancy-solute clusters by the addition of small percentages of Cu to Al-Zn-Mg has been studied by positron annihilation lifetime spectroscopy. The results document the ability of Cu to increase the number of vacancies retained after quenching, by forming an additional population of vacancy-solute clusters in competition with pure Zn clusters. It has also been shown that Cu accelerates the decomposition of the alloy at 150 , thereby leaving a reduced supersaturation of the matrix after an early interruption. An unexpected result is that the curve positron lifetime vs, ageing time at RT displays the symptoms of a change in the nature of the coherent aggregates that occurs in about 10 hours of RT exposure. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. Synthesis of Cu doped ZnS nanostructures on flexible substrate using low cost chemical method

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Nitin, E-mail: nitinmishra97@gmail.com; Purohit, L. P., E-mail: lppurohit@gmail.com [Gurukula Kangari University, Haridwar UK (India); Goswami, Y. C., E-mail: y-goswami@yahoo.com [ITM University, Turari, Gwalior, MP (India)

    2015-08-28

    Flexible electronics is one of the emerging area of this era. In this paper we have reported synthesis of Cu doped Zinc sulphide nanostructures on filter paper flexible substrates. Zinc chloride and Thio urea were used as a precursor for Zinc and Sulphur. The structures were characterized by XRD, FE-SEM and UV visible spectrometer. All the peaks identified for cubic structure of ZnS. Appearance of small Cu peaks indicates incorporation of Cu into ZnS lattice. Zns nanostructures assembled as nanobelts and nanofibers as shown in FE-SEM micrographs. Compound Structures provide the reasonable electrical conductivity on filter paper. Absorption in UV region makes them suitable for flexible electronic devices.

  15. Comparison of serum Concentration of Se, Pb, Mg, Cu, Zn, between MS patients and healthy controls

    Science.gov (United States)

    Alizadeh, Anahita; Mehrpour, Omid; Nikkhah, Karim; Bayat, Golnaz; Espandani, Mahsa; Golzari, Alireza; Jarahi, Lida; Foroughipour, Mohsen

    2016-01-01

    Introduction Multiple Sclerosis (MS) is defined as one of the inflammatory autoimmune disorders and is common. Its exact etiology is unclear. There are some evidences on the role of environmental factors in susceptible genetics. The aim of this study is to evaluate the possible role of Selenium, Zinc, Copper, Lead and Magnesium metals in Multiple Sclerosis patients. Methods In the present analytical cross-sectional study, 56 individuals including 26 patients and 30 healthy controls were enrolled in the evaluation. The serum level of Se, Zn, Cu, Pb were quantified in graphite furnace conditions and flame conditions by utilizing an atomic absorption Perkin Elmer spectrophotometer 3030. The serum levels of Mg were measured by auto analyzer 1500 BT. The mean level of minerals (Zn, Pb, Cu, Mg, Se) in serum samples were compared in both cases and controls. The mean level of minerals (Zn, Pb, Cu, Mg, Se) in serum samples were compared in both cases and controls by using independent-samples t-test for normal distribution and Mann-Whitney U test as a non-parametric test. All statistical analyses were carried out using SPSS 11.0. Results As well as the Zn, Cu, and Se, there was no significant difference between MS patients and healthy individuals in Pb concentrations (p-value = 0.11, 0.14, 0.32, 0.20 respectively) but the level of Mg was significantly different (p= 0.001). Conclusion All serum concentrations of Zn, Pb, Se, Cu in both groups were in normal ranges and there was no difference in MS patients compared with the healthy group who were matched in genetics. Blood level of Mg was significantly lower in MS patients. But it should be noted that even with the low level of serum magnesium in MS patients, this value is still in the normal range. PMID:27757186

  16. Preparation and electrical properties of Ni-Cu-Zn system doped with the magnesium oxide

    Science.gov (United States)

    Hemeda, O. M.; Tawfik, A.; Hemeda, D. M.; Elsheekh, A. M.

    2014-06-01

    A sery of ferrite samples, Ni0.1Cu0.2MgxZn0.7-xFe2O4, (x = 0.00, 0.15, 0.25, 0.35, 0.45, 0.55 and 0.70) have been prepared by the standard ceramic techniques, sintered at 1200°C for 2 h, and their crystalline structures were investigated by using X-ray diffraction, which confirmed the formation of Ni0.1Cu0.2MgxZn0.7-xFe2O4 phase. The presence of Mg content increases the crystallinity of the given ferrite which is considered as catalyst for the accomplishment of the solid state reaction. The lattice parameter and crystallite size were calculated from XRD. The cationic distribution was estimated from the theoretical values of lattice parameters. The IR spectra analysis has been studied. The dielectric constant for the ferrite system Ni-Cu-Zn gradually increases with temperature up to nearly Curie temperature and then increase sharply beyond the Tc. The Curie temperature obtained from the ´ ǎrepsilon versus T is in agreement with the Curie temperature obtained from other measurements. Dielectric loss tangent (tan δ) has the same behavior as dielectric constant (´ ǎrepsilon). A minimum value of dielectric loss tangent (tan δ) for the system "Ni-Cu-Zn" was observed at x = 0.45. Magnetic permeability has been studied. The dependence of initial permeability on temperature exhibit a peak which is called Hopkinson peak (HP) in the vicinity of Curie temperature and confirmed the phase purity of ferrite sample. The increasing of porosity and decreasing of grain size play an important role in decreasing μi. It is clear that the value of Tc is found to increase by increasing the concentration of diamagnetic substitution Mg for "Ni-Cu-Zn" system.

  17. Study of NiCuZn ferrite powders and films prepared by sol-gel method

    Institute of Scientific and Technical Information of China (English)

    Gao Liang-Qiu; Yu Guo-Jian; Wang Ying; Wei Fu-Lin

    2011-01-01

    This paper reports that a series of NiCuZn ferrite powders and films are prepared by using sol-gel method. The effects of raw material composition and the calcinate temperature on magnetic properties of them are investigated. The NiCuZn ferrite powders are prepared by the self-propagating high-temperature synthesis method and subsequently heated at 700 ℃~1000 ℃. The results show that NiCuZn ferrite powders with single spinel phase can be formed after heat-treating at 750 ℃. Powders obtained from Nio.4Cuo.2Zno.4Fe1.9O4 gel have better magnetic properties than those from gels with other composition. After heat-treating at 900 ℃ for 3 h, coercivity Hc and saturation magnetization Ms are 9.7 Oe (1 Oe = 80 A/m) and 72.4 emu/g, respectively. Different from the powders, NiCuZn films produced on Si (100) from the Ni0.4Cu0.2Zn0.4Fe2O4 gel formed at room temperature possess high properties. When heat-treating condition is around 600 ℃ for 6 min, samples with low Hc and high Ms will be obtained. The minimal Hc is 16.7 Oe and Ms is about 300 emu/cm3. In comparison with the films prepared through long-time heat treating, the films prepared through short heat-treating time exhibits better soft magnetic properties.

  18. The influence of precursor Cu content and two-stage processing conditions on the microstructure of Cu{sub 2}ZnSnSe{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Márquez-Prieto, J., E-mail: jose.prieto@northumbria.ac.uk [Northumbria Photovoltaic Application Centre, Faculty of Engineering and Environment, Northumbria University, Ellison Building, Newcastle upon Tyne NE1 8ST (United Kingdom); Ren, Y. [Ångström Solar Center, Solid State Electronics, Uppsala University, Uppsala 751 21 (Sweden); Miles, R.W.; Pearsall, N.; Forbes, I. [Northumbria Photovoltaic Application Centre, Faculty of Engineering and Environment, Northumbria University, Ellison Building, Newcastle upon Tyne NE1 8ST (United Kingdom)

    2015-05-01

    This paper reports the influence of processing temperature on the microstructure of Cu{sub 2}ZnSnSe{sub 4} (CZTSe) absorber layers for temperatures between 380 and 550 °C produced using a 2-stage process. X-ray diffraction analysis showed the formation of Cu{sub 2}ZnSnSe{sub 4} over this temperatures range. The Williamson-Hall method was used for microstructural analysis of the CZTSe absorbers, and this showed a progressive decrease of the micro-strain of the CZTSe with increasing selenisation temperature. The influence of precursor Cu content on the microstructure of the CZTSe was also studied. An increase of Cu content in the precursor is correlated to an increase in grain size and a decrease in micro-strain. Raman measurements show an asymmetrical broadening towards lower energies of the main 197 cm{sup −1} mode for Cu-poor compositions. This study provides an insight into the dependency of the crystallinity of CZTSe on composition and synthesis temperature. - Highlights: • We fabricate Cu{sub 2}ZnSnSe{sub 4} thin films by sputtering and post-reactive annealing. • The micro-strain of Cu{sub 2}ZnSnSe{sub 4} increases when Cu content decreases. • The micro-strain of Cu{sub 2}ZnSnSe{sub 4} decreases with increasing processing temperature. • The defect concentration of Cu{sub 2}ZnSnSe{sub 4} increases when Cu content decreases.

  19. Enhanced Photo catalytic Activity of ZnO/CuO Nano comp osites Synthesized by Hydrothermal Metho d

    Institute of Scientific and Technical Information of China (English)

    Tongqin Chang; Zijiong Li∗; Gaoqian Yun; Yong Jia; Hongjun Yang

    2013-01-01

    In this paper, we have demonstrated a facile and low-cost synthesis of the ZnO/CuO nanocom-posites by two-step hydrothermal methods. The photocatalytic properties of the as-synthesized ZnO/CuO nanocomposites have been evaluated by the photodegradation of methylene blue (MB) and methyleneorange (MO) under UV irradiation. Experimental results show that MB and MO can be degraded completely within 15 and 25 min by the ZnO/CuO nanocomposites and its photodegradation rate is 6 times faster than that of pure ZnO. This enhanced photocatalytic activity can be ascribed to the low recombination probability of photo-induced carriers due to the efficient charge transfer in the nanocomposites. The as-synthesized ZnO/CuO nanocomposite may be a promising candidate for dye photodegradation of wastewaters.

  20. Influence of Li Addition to Zn-Al Alloys on Cu Substrate During Spreading Test and After Aging Treatment

    Science.gov (United States)

    Gancarz, Tomasz; Pstrus, Janusz; Cempura, Grzegorz; Berent, Katarzyna

    2016-08-01

    The spreading of Zn-Al eutectic-based alloys with 0.05 wt.%, 0.1 wt.%, and 0.2 wt.% Li on Cu substrate has been studied using the sessile drop method in presence of QJ201 flux. Wetting tests were performed after 1 min, 3 min, 8 min, 15 min, 30 min, and 60 min of contact at temperatures of 475°C, 500°C, 525°C, and 550°C. Samples after spreading at 500°C for 1 min were subjected to aging for 1 day, 10 days, and 30 days at temperature of 120°C, 170°C, and 250°C. The spreadability of eutectic Zn-5.3Al alloy with different Li contents on Cu substrate was determined in accordance with ISO 9455-10:2013-03. Selected solidified solder-substrate couples were, after spreading and aging tests, cross-sectioned and subjected to scanning electron microscopy, energy-dispersive spectroscopy (EDS), and x-ray diffraction (XRD) analysis of the interfacial microstructure. An experiment was designed to demonstrate the effect of Li addition on the kinetics of the formation and growth of CuZn, Cu5Zn8, and CuZn4 intermetallic compound (IMC) phases, during spreading and aging. The IMC layers formed at the interface were identified using XRD and EDS analyses. Increasing addition of Li to Zn-Al alloy caused a reduction in the thickness of the IMC layer at the interface during spreading, and an increase during aging. The activation energy was calculated, being found to increase for the Cu5Zn8 phase but decrease for the CuZn and CuZn4 phases with increasing Li content in the Zn-Al-Li alloys. The highest value of 142 kJ mol-1 was obtained for Zn-Al with 1.0 Li during spreading and 69.2 kJ mol-1 for Zn-Al with 0.05 Li during aging. Aging at 250°C caused an increase in only the Cu5Zn8 layer, which has the lowest Gibbs energy in the Cu-Zn system. This result is connected to the high diffusion of Cu from the substrate to the solder.

  1. Influence of Li Addition to Zn-Al Alloys on Cu Substrate During Spreading Test and After Aging Treatment

    Science.gov (United States)

    Gancarz, Tomasz; Pstrus, Janusz; Cempura, Grzegorz; Berent, Katarzyna

    2016-12-01

    The spreading of Zn-Al eutectic-based alloys with 0.05 wt.%, 0.1 wt.%, and 0.2 wt.% Li on Cu substrate has been studied using the sessile drop method in presence of QJ201 flux. Wetting tests were performed after 1 min, 3 min, 8 min, 15 min, 30 min, and 60 min of contact at temperatures of 475°C, 500°C, 525°C, and 550°C. Samples after spreading at 500°C for 1 min were subjected to aging for 1 day, 10 days, and 30 days at temperature of 120°C, 170°C, and 250°C. The spreadability of eutectic Zn-5.3Al alloy with different Li contents on Cu substrate was determined in accordance with ISO 9455-10:2013-03. Selected solidified solder-substrate couples were, after spreading and aging tests, cross-sectioned and subjected to scanning electron microscopy, energy-dispersive spectroscopy (EDS), and x-ray diffraction (XRD) analysis of the interfacial microstructure. An experiment was designed to demonstrate the effect of Li addition on the kinetics of the formation and growth of CuZn, Cu5Zn8, and CuZn4 intermetallic compound (IMC) phases, during spreading and aging. The IMC layers formed at the interface were identified using XRD and EDS analyses. Increasing addition of Li to Zn-Al alloy caused a reduction in the thickness of the IMC layer at the interface during spreading, and an increase during aging. The activation energy was calculated, being found to increase for the Cu5Zn8 phase but decrease for the CuZn and CuZn4 phases with increasing Li content in the Zn-Al-Li alloys. The highest value of 142 kJ mol-1 was obtained for Zn-Al with 1.0 Li during spreading and 69.2 kJ mol-1 for Zn-Al with 0.05 Li during aging. Aging at 250°C caused an increase in only the Cu5Zn8 layer, which has the lowest Gibbs energy in the Cu-Zn system. This result is connected to the high diffusion of Cu from the substrate to the solder.

  2. Advance in Cu2O-ZnO Solar Cells and Investigation of Cu2O-ZnO Heterojunction Fabricated by Magnetron Sputtering%Cu2O-ZnO太阳能电池的研究进展及磁控溅射法制备Cu2O-ZnO异质结的研究

    Institute of Scientific and Technical Information of China (English)

    杨美佳; 朱丽萍

    2013-01-01

    Cu2O-ZnO heterojunction has shown great potential for photovoltaic application due to the low-cost,nontoxicity,abundance and variety of preparation methods.However,the resistivity of the Cu2O film in present ZnO-Cu2O heterojunction solar cell is relatively high,which seems to be the major problem for the low photoelectric conversion efficiency.Cu2O films were prepared using reactive direct current magnetron sputtering.The microstructures and properties were characterized using X-ray diffraction,X-ray photoelectron spectroscopy (XPS) and Hall-effect measurements.The influences of qv (Ar) ∶ qv (O2) on the structures and properties of deposited films were investigated.Single-phase Cu2O film with a resistivity of 88.5 Ω · cm,a Hall mobility of 16.9 cm2 · V-1 · s-1 and a carrier concentration of 4.19 × 1015 cm-3 were obtained at qv (Ar) ∶ qv (O2) =90∶ 0.3.The as-deposited Cu2O films have a great improvement in electrical performance and have more advantage in photovoltaic application compared with that prepared by electrochemical deposition or thermal oxidation.On that basis,the Cu2O-ZnO heterojunctions were fabricated in reversed growth sequence and the band alignments of the heterojunctions were given to investigate their potential application in solar cells.Possible areas for future work in this field were outlined and some suggestions were made based on our investigation of the Cu2O-ZnO heterojunctions fabricated by magnetron sputtering.%Cu2O-ZnO异质结具有成本低廉、环境友好及制备方法多样等优点,在太阳能电池领域有很好的应用前景.Cu2O薄膜的高电阻率和低载流子浓度是制约其效率提高的主要原因.本文采用磁控溅射法,在qv(Ar)∶qv(O2) =90∶0.3时得到单相p型Cu2O薄膜,电阻率为88.5 Ω·cm,霍尔迁移率为16.9 cm2·V-1·s-1,载流子浓度为4.19×1015cm-3.并结合Cu2O-ZnO异质结能带结构的研究,对Cu2O-ZnO异质结太阳能电池今后的研究提出了一些建议.

  3. Effects of Pb2+, Cd2+ and Cu2+ on the Aqueous Zn2+ Sorption by Hydroxyapatite

    Institute of Scientific and Technical Information of China (English)

    QI Yong; LIU Yu

    2006-01-01

    In this paper, the behaviors of aqueous zinc sorption by hydroxyapatite in the co-existence of Pb2+, Cd2+ and Cu2+ are investigated, the effects of Pb2+, Cd2+ and Cu2+ on the sorption of Zn2+ are discussed, and the hydroxyapatite sorption capabilities for Pb2+, Cd2+, Cu2+ and Zn2+ are compared.The experimental results show that the Zn2+ removal efficiency decreases gradually with the increase of the Cd2+ concentration of the solution, and there is no sorption preference between Cd2+ and Zn2+. On the other hand, the Zn2+ removal efficiency rapidly decreases rapidly with the increase of the Cu2+ concentration of the solution, and there is a clear sorption preference between Cu2+ and Zn2+. It is noticed that the Zn2+ removal efficiency is hardly changed with the variance of Pb2+ concentration because the removal mechanisms for these two ions are totally different. It is concluded that the adsorption affinities of the heavy metals for the hydroxyapatite follows this sequence: Pb2+> Cu2+>Cd2+> Zn2+.

  4. Facile fabrication of n-ZnO nanorods/p-Cu2O heterojunction and its photodiode property

    Science.gov (United States)

    Kathalingam, A.; Vikraman, Dhanasekaran; Kim, Hyun-Seok; Park, Hui Joon

    2017-04-01

    This report presents the fabrication and characterization of n-ZnO nanorods/p-Cu2O hetrojunction photo-diode. The ZnO nanorods (NRs) were deposited onto electrodeposited Cu2O thin film by hydrothermal method. The structural, morphological and optical properties of ZnO NRs and Cu2O films were studied by X-ray diffraction, scanning electronic microscopy, UV-Vis spectrophotometer, respectively. XRD patterns revealed that the as-grown films were highly crystalline nature with strong predominant orientation of (111) and (002) lattices corresponding to Cu2O and ZnO NRs, respectively. Current-voltage (I-V) characteristic of n-ZnONRs/p-Cu2O structure confirmed the formation of heterojunction exhibiting diode-like rectifying nature. It showed enhanced conversion of UV light, which indicates the suitability of the simple and low-cost n-ZnO NRs/p-Cu2O heterojunction device for optoelectronic applications. The sandwich type ITO/n-ZnO NRs/p-Cu2O/ITO structure is quite novel approach for the efficient and complete collection of carriers in nanorods incorporated devices.

  5. Influence of Cu content on the mechanical properties and corrosion resistance of Mg-Zn-Ca bulk metallic glasses

    Science.gov (United States)

    Zhao, Yan-feng; Zhu, Jian; Chang, Li; Song, Jing-guo; Chen, Xiao-hua; Hui, Xi-dong

    2014-05-01

    (Mg66.2Zn28.8Ca5)100- x Cu x (at%, x = 0, 1, 3, and 5) bulk metallic glasses (BMGs) of 2 mm in diameter were prepared by the conventional copper mold injection casting method. Besides, the influence of Cu content on the microstructure, thermal stability, mechanical properties, and corrosion behavior of Mg-Zn-Ca BMGs was investigated. It is found that the addition of Cu decreases the glass-forming ability of Mg-Zn-Ca BMGs. Crystalline phases are precipitated at a higher Cu content, larger than 3at%. The compressive fracture strength of Mg-Zn-Ca BMGs is enhanced by the addition of Cu. With the formation of in-situ composites, the compressive strength of the Mg-Zn-Ca alloy with 3at% Cu reaches 979 MPa, which is the highest strength among the Mg-Zn-Ca alloys. Furthermore, the addition of Cu also results in the increase of corrosion potential and the decrease of corrosion current density in Mg-Zn-Ca BMGs, thereby delaying their biodegradability.

  6. Cu2ZnSnS4 solar cells prepared by sulfurization of sputtered ZnS/Sn/CuS precursors

    Science.gov (United States)

    Li, Zhi-Shan; Wang, Shu-Rong; Jiang, Zhi; Yang, Min; Lu, Yi-Lei; Liu, Si-Jia; Zhao, Qi-Chen; Hao, Rui-Ting

    2016-12-01

    Cu2ZnSnS4 (CZTS) thin films were grown on Mo-coated Soda-lime-glass (SLG) substrates by sulfurization of sputtered ZnS/Sn/CuS precursors at different temperatures i.e. 560 °C, 580 °C and 600 °C. The effects of sulfurization temperature on the quality of CZTS thin films and solar cells were investigated. The crystal structure, surface morphology, chemical composition, phase purity and surface roughness of CZTS thin films fabricated at different sulfurization temperatures were characterized by X Ray Diffraction (XRD), scanning electron microscopy (SEM) equipped with an energy dispersive spectrometer (EDS), Raman spectroscopy and atomic force microscope (AFM), respectively. The results show that all CZTS thin films exhibit a polycrystalline kesterite structure and preferred (112) orientation. For the sulfurization temperature of 580 °C, the obtained CZTS thin films are dense and flat with larger grain size. Meanwhile composition studying indicates that the fabricated CZTS with single phase is copper poor and zinc rich. Furthermore, the surface roughness of CZTS film is the lowest. Finally, the CZTS solar cells with the structure of SLG/Mo/CZTS/CdS/i-ZnO/ITO/Al were fabricated and demonstrated the best power conversion efficiency of 3.59% when used sulfurization temperature was 580 °C.

  7. Cu{sub 2}ZnSnS{sub 4} solar cells prepared by sulfurization of sputtered ZnS/Sn/CuS precursors

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhi-Shan; Wang, Shu-Rong, E-mail: shrw88@aliyun.com; Jiang, Zhi; Yang, Min; Lu, Yi-Lei; Liu, Si-Jia; Zhao, Qi-Chen; Hao, Rui-Ting

    2016-12-01

    Cu{sub 2}ZnSnS{sub 4} (CZTS) thin films were grown on Mo-coated Soda-lime-glass (SLG) substrates by sulfurization of sputtered ZnS/Sn/CuS precursors at different temperatures i.e. 560 °C, 580 °C and 600 °C. The effects of sulfurization temperature on the quality of CZTS thin films and solar cells were investigated. The crystal structure, surface morphology, chemical composition, phase purity and surface roughness of CZTS thin films fabricated at different sulfurization temperatures were characterized by X Ray Diffraction (XRD), scanning electron microscopy (SEM) equipped with an energy dispersive spectrometer (EDS), Raman spectroscopy and atomic force microscope (AFM), respectively. The results show that all CZTS thin films exhibit a polycrystalline kesterite structure and preferred (112) orientation. For the sulfurization temperature of 580 °C, the obtained CZTS thin films are dense and flat with larger grain size. Meanwhile composition studying indicates that the fabricated CZTS with single phase is copper poor and zinc rich. Furthermore, the surface roughness of CZTS film is the lowest. Finally, the CZTS solar cells with the structure of SLG/Mo/CZTS/CdS/i-ZnO/ITO/Al were fabricated and demonstrated the best power conversion efficiency of 3.59% when used sulfurization temperature was 580 °C.

  8. CuO/ZnO catalysts for methanol steam reforming: The role of the support polarity ratio and surface area

    OpenAIRE

    2015-01-01

    The effect of surface area and polarity ratio of ZnO support on the catalytic properties of CuO/ZnO catalyst for methanol steam reforming (MSR) are studied. The surface area of ZnO was varied changing the calcination temperature and its polarity ratio was modified using different Zn precursors, zinc acetate and zinc nitrate. It was found that the copper dispersion and copper surface area increase with the surface area of the ZnO support and the polarity ratio of ZnO strongly in...

  9. Growth of Zn doped Cu(In, Ga)Se 2 thin films by RF sputtering for solar cell applications

    Science.gov (United States)

    Li, Z. Q.; Liu, Q. Q.; Li, J. J.; Sun, Z.; Chen, Y. W.; Yang, Z.; Huang, S. M.

    2012-02-01

    Cu(In, Ga)Se 2 (CIGS) surface was modified with Zn doping using a magnetron sputtering method. CuInGa:Zn precursor films targeting a CuIn 0.7Ga 0.3Se 2 stoichiometry with increasing Zn content from 0 to 0.8 at% were prepared onto Mo-coated glass substrates via co-sputtering of Cu-Ga alloy, In and Zn targets. The CuInGa:Zn precursors were then selenized with solid Se pellets. The structures and morphologies of grown Zn doped CIGS films were found to depend on the Zn content. At zinc doping level ranging between 0.2 and 0.6 at%, the Zn doping improved the crystallinity and surface morphology of CIGS films. Compared with the performance of the non-doped CIGS cell, the fabricated CIGS solar cell displayed a relative efficiency enhancement of 9-22% and the maximum enhancement was obtained at a Zn content of 0.4 at%.

  10. Nanostructured Al-ZnO/CdSe/Cu2O ETA solar cells on Al-ZnO film/quartz glass templates

    Science.gov (United States)

    Wang, Xianghu; Li, Rongbin; Fan, Donghua

    2011-12-01

    The quartz/Al-ZnO film/nanostructured Al-ZnO/CdSe/Cu2O extremely thin absorber solar cell has been successfully realized. The Al-doped ZnO one-dimensional nanostructures on quartz templates covered by a sputtering Al-doped ZnO film was used as the n-type electrode. A 19- to 35-nm-thin layer of CdSe absorber was deposited by radio frequency magnetron sputtering, coating the ZnO nanostructures. The voids between the Al-ZnO/CdSe nanostructures were filled with p-type Cu2O, and therefore, the entire assembly formed a p-i-n junction. The cell shows the energy conversion efficiency as high as 3.16%, which is an interesting option for developing new solar cell devices. PACS: 88.40.jp; 73.40.Lq; 73.50.Pz.

  11. Synthesis and characterization of Cu-Zn/TiO2 for the photocatalytic conversion of CO2 to methane.

    Science.gov (United States)

    Rana, Adeem Ghaffar; Ahmad, Waqar; Al-Matar, Ali; Shawabkeh, Reyad; Aslam, Zaheer

    2017-05-01

    Different Cu-Zn/TiO2 catalysts were synthesized by using the wet impregnation method. The prepared catalysts were used for the conversion of CO2 into methane by photocatalysis. Various characterization techniques were used to observe the surface morphology, crystalline phase, Brunauer-Emmett-Teller (BET) surface area, presence of impregnated Cu and Zn, and functional group. Scanning electron microscope analysis showed spherical morphology, and slight agglomeration of catalyst particles was observed. BET analysis revealed that the surface area of the catalyst was decreased from 10 to 8.5 m(2)/g after impregnation of Cu and Zn over TiO2 support. Synergetic effect of Cu and Zn over TiO2 support (Cu2.6/TiO2, Zn0.5/TiO2 and Cu2.6-Zn0.5/TiO2) and the effects of Cu loading (0, 1.8, 2.1, 2.6 and 2.9 wt%) were also investigated at different feed molar ratios of H2/CO2 (2:1 and 4:1). The Cu2.6-Zn0.5/TiO2 catalyst showed a maximum conversion of 14.3% at a feed molar ratio of 4. The addition of Zn over the catalyst surface increased the conversion of CO2 from 10% to 14.3% which might be due to synergy of Cu and Zn over TiO2 support.

  12. Facile synthesis of ZnO/CuInS{sub 2} nanorod arrays for photocatalytic pollutants degradation

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yawei [Electronic Materials Research Laboratory, International Center for Dielectric Research, Key Laboratory of the Ministry of Education, School of Electronic & Information Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China); Que, Wenxiu, E-mail: wxque@mail.xjtu.edu.cn [Electronic Materials Research Laboratory, International Center for Dielectric Research, Key Laboratory of the Ministry of Education, School of Electronic & Information Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China); Zhang, Xinyu [Frontier Institute of Science and Technology Jointly with College of Science, State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China); Xing, Yonglei; Yin, Xingtian [Electronic Materials Research Laboratory, International Center for Dielectric Research, Key Laboratory of the Ministry of Education, School of Electronic & Information Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China); Du, Yaping, E-mail: ypdu2013@mail.xjtu.edu.cn [Frontier Institute of Science and Technology Jointly with College of Science, State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China)

    2016-11-05

    Highlights: • Vertically-aligned ZnO nanorod arrays were synthesized by the hydrothermal process. • Monodisperse CuInS{sub 2} QDs were synthesized by the one-pot colloidal chemistry method. • ZnO/CuInS{sub 2} nanorod arrays films were fabricated by the EPD process. • The homogeneous CuInS{sub 2} loading was optimized by EPD duration. • The photoelectrochemical and photocatalytic activities of the ZnO/CuInS{sub 2} nanorod arrays films were discussed. - Abstract: Vertically-aligned ZnO nanorod arrays on a fluorine-doped tin oxide glass substrate were homogeneously coated with visible light active CuInS{sub 2} quantum dots by using a controllable electrophoretic deposition strategy. Compared with the pure ZnO nanorod arrays, the formation of high-quality ZnO/CuInS{sub 2} heterojunction with well-matched band energy alignment expanded the light absorption from ultraviolet to visible region and facilitated efficient charge separation and transportation, thus yielding remarkable enhanced photoelectrochemical performance and photocatalytic activities for methyl orange and 4-chlorophenol degradation. The ZnO/CuInS{sub 2} film with the deposition duration of 80 min showed the highest degradation rate and photocurrent density (0.95 mA/cm{sup 2}), which was almost 6.33 times higher than that of the pure ZnO nanorod arrays film. The CuInS{sub 2} QDs sensitized ZnO nanorod arrays film was proved to be a superior structure for photoelectrochemical and photocatalytic applications due to the optimized CuInS{sub 2} loading and well-maintained one-dimensional nanostructure.

  13. Synthesis and electrical characterization of vertically-aligned ZnO–CuO hybrid nanowire p–n junctions

    Energy Technology Data Exchange (ETDEWEB)

    Pukird, Supakorn [Department of Physics, Faculty of Science, Ubon Ratchathani University, Ubon Ratchathani 34190 (Thailand); Song, Wooseok [Thin Film Materials Research Group, Korea Research Institute of Chemical Technology, Yuseong Post Office Box 107, Daejeon 305-600 (Korea, Republic of); Noothongkaew, Suttinart [Department of Physics, Faculty of Science, Ubon Ratchathani University, Ubon Ratchathani 34190 (Thailand); Kim, Seong Ku [Department of Chemical Engineering and Materials Science, University of California, Davis, CA 95616 (United States); Min, Bok Ki; Kim, Seong Jun; Kim, Ki Woong; Myung, Sung [Thin Film Materials Research Group, Korea Research Institute of Chemical Technology, Yuseong Post Office Box 107, Daejeon 305-600 (Korea, Republic of); An, Ki-Seok, E-mail: ksan@skku.edu [Thin Film Materials Research Group, Korea Research Institute of Chemical Technology, Yuseong Post Office Box 107, Daejeon 305-600 (Korea, Republic of)

    2015-10-01

    Highlights: • Vertically-aligned ZnO–CuO hybrid nanowire arrays were synthesized by a two-step thermal chemical vapor deposition process. • The diameter of parallel-connected ZnO and CuO NWs were estimated to be 146 ± 12 nm and 55 ± 11 nm, respectively, and the formation of high-quality hexagonal ZnO and monoclinic CuO NWs were observed. • Clear rectifying behavior related with thermionic emission of carriers and the presence of an electrical potential barrier between the ZnO and CuO NWs were observed. - Abstract: In order to form nanowire (NW)-based p–n junctions, vertically-aligned ZnO–CuO hybrid NW arrays were synthesized by a two-step thermal chemical vapor deposition process. The diameter of parallel-connected ZnO and CuO NWs were estimated to be 146 ± 12 nm and 55 ± 11 nm, respectively, as observed by scanning electron microscopy. Chemical and structural characterizations of ZnO–CuO hybrid NW arrays were performed using X-ray photoelectron spectroscopy and X-ray diffraction, resulting in the formation of high-quality hexagonal ZnO and monoclinic CuO NWs. The temperature dependence of I–V curves and impedance spectra suggested that clear rectifying behavior related with thermionic emission of carriers and the presence of an electrical potential barrier between the ZnO and CuO NWs.

  14. Rotating ring-disk electrode studies of Cu-Zn alloy electrodissolution in 1M HCl: Effect of benzotriazole

    Energy Technology Data Exchange (ETDEWEB)

    Costa, S.L.F.A. da; Nobe, K. [Univ. of California, Los Angeles, CA (United States). Dept. of Chemical Engineering; Agostinho, S.M.L. [Univ. de Sao Paulo (Brazil). Dept. de Quimica Fundamental

    1993-12-01

    The electrodissolution behavior of Cu and Cu-rich Cu-Zn alloys in 1M HCl containing benzotriazole (BTA) was studied using rotating ring-disk electrodes. Cu(I) was the main product of Cu-Zn alloy dissolution with Cu(II) detected only at higher potentials. Electrodissolution of the Cu component was similar to that of copper with an apparent Tafel slope of 60 mV/dec. Cu component dissolution rates exhibited strong mass-transfer effects in the entire potential range studied. A CuCl film formed on the alloy surfaces in the current peak region. In the limiting current region the rates of Cu(I) dissolution from both alloys and copper were essentially equivalent and indicate CuCl{sup {minus}}{sub 2} as the principal diffusing species. Significant selective electrodissolution of Zn was observed in the apparent Tafel region. The formation of a duplex film was indicated in the presence of BTA with a nonporous Cu(I) BTA inner layer and a porous CuCl outer layer.

  15. In-situ XRD study of alloyed Cu{sub 2}ZnSnSe{sub 4}-CuInSe{sub 2} thin films for solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Hartnauer, Stefan; Wägele, Leonard A.; Jarzembowski, Enrico; Scheer, Roland, E-mail: roland.scheer@physik.uni-halle.de

    2015-05-01

    We investigate the growth of Cu{sub 2}ZnSnSe{sub 4}-CuInSe{sub 2} (CZTISe) thin films using a 2-stage (Cu-rich/Cu-free) co-evaporation process under simultaneous application of in-situ angle dispersive X-ray diffraction (XRD). In-situ XRD allows monitoring the phase formation during preparation. A variation of the content of indium in CZTISe leads to a change in the lattice constant. Single phase CZTISe is formed in a wide range, while at high In contents a phase separation is detected. Because of different thermal expansion coefficients, the X-ray diffraction peaks of ZnSe and CZTISe can be distinguished at elevated substrate temperatures. The formation of ZnSe appears to be inhibited even for low indium content. In-situ XRD shows no detectable sign for the formation of ZnSe. First solar cells of CZTISe have been prepared and show comparable performance to CZTSe. - Highlights: • In-situ XRD study of two-stage co-evaporated Cu{sub 2}ZnSnSe{sub 4}-CuInSe{sub 2} alloyed thin films. • No detection of ZnSe with in-situ XRD due to Indium incorporation • Comparable efficiency of alloyed solar cells.

  16. First-principles calculations of vacancy formation in In-free photovoltaic semiconductor Cu{sub 2}ZnSnSe{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, Tsuyoshi, E-mail: tmaeda@ad.ryukoku.ac.jp; Nakamura, Satoshi; Wada, Takahiro

    2011-08-31

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

  17. Microstructural characterization of Cu/ZnO/Al2O3 catalysts for the synthesis and steam reforming of methanol

    OpenAIRE

    2008-01-01

    Cu/ZnO/Al2O3 catalysts represent a versatile catalyst system for methanol chemistry, including the synthesis and steam reforming of methanol. Formally, the steam reforming of methanol is the reverse of methanol synthesis from CO2 and H2. In the present work a set of differently prepared Cu/ZnO/Al2O3 catalysts with a fixed composition of Cu/Zn/Al = 60:30:10 were investigated by in situ bulk techniques, X-ray diffraction, and X-ray absorption spectroscopy. Additionally, microscopic and morpholo...

  18. Growth and characterization of Cu2ZnSn(S,Se)4 thin films for solar cells

    OpenAIRE

    Salomé, P M P; Malaquias, J; Fernandes, P. A.; Ferreira, M. S.; Cunha, A. F. da; Leitão, J. P.; J. C. González; Matinaga, F. M.

    2012-01-01

    Cu2ZnSnS4 (CZTS) and Cu2ZnSnSe4 (CZTSe) with their band gap energies around 1.45 eV and 1.0 eV, respectively, can be used as the absorber layer in thin film solar cells. By using a mixture of both compounds, Cu2ZnSn(S,Se)4 (CZTSSe), a band gap tuning may be possible. The latter material has already shown promising results such as solar cell efficiencies up to 10.1%. In this work, CZTSSe thin films were grown in order to study its structure and to establish the best growth precurso...

  19. Trace amounts of Cu{sup 2+} ions influence ROS production and cytotoxicity of ZnO quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Moussa, Hatem [CNRS and Université de Lorraine, Laboratoire Réactions et Génie des Procédés (LRGP), CNRS UMR 7274, 1 rue Grandville, 54001 Nancy (France); Laboratoire de Biosurveillance de l' Environnement, Université de Carthage, Faculté des Sciences de Bizerte, 7021 Jarzouna, Bizerte (Tunisia); Merlin, Christophe [CNRS and Université de Lorraine, Laboratoire de Chimie Physique et Microbiologie pour l' Environnement (LCPME), CNRS UMR 7564, 15 Avenue du Charmois, 54500 Vandoeuvre-lès-Nancy (France); Dezanet, Clément [CNRS and Université de Lorraine, Laboratoire Réactions et Génie des Procédés (LRGP), CNRS UMR 7274, 1 rue Grandville, 54001 Nancy (France); Balan, Lavinia [Institut de Science des Matériaux de Mulhouse (IS2M), CNRS UMR 7361, 15 rue Jean Starcky, 68093 Mulhouse (France); Medjahdi, Ghouti [CNRS and Université de Lorraine, Institut Jean Lamour (IJL), UMR CNRS 7198, BP 70239, 54506 Vandoeuvre-lès-Nancy Cedex (France); Ben-Attia, Mossadok [Laboratoire de Biosurveillance de l' Environnement, Université de Carthage, Faculté des Sciences de Bizerte, 7021 Jarzouna, Bizerte (Tunisia); and others

    2016-03-05

    Highlights: • Chemisorbed Cu{sup 2+} ions on ZnO QDs enhance ROS production. • A mechanism combining excited electrons and holes and Fenton reactions is proposed. • ZnO@APTMS/Cu QDs were found to be the most deleterious to E. coli cells. - Abstract: 3-Aminopropyltrimethoxysilane (APTMS) was used as ligand to prepare ZnO@APTMS, Cu{sup 2+}-doped ZnO (ZnO:Cu@APTMS) and ZnO quantum dots (QDs) with chemisorbed Cu{sup 2+} ions at their surface (ZnO@APTMS/Cu). The dots have a diameter of ca. 5 nm and their crystalline and phase purities and composition were established by X-ray diffraction, transmission electron microscopy, UV-visible and fluorescence spectroscopies and by X-ray photoelectron spectroscopy. The effect of Cu{sup 2+} location on the ability of the QDs to generate reactive oxygen species (ROS) under light irradiation was investigated. Results obtained demonstrate that all dots are able to produce ROS (·OH, O{sub 2}·{sup −}, H{sub 2}O{sub 2} and {sup 1}O{sub 2}) and that ZnO@APTMS/Cu QDs generate more ·OH and O{sub 2}·{sup −} radicals and H{sub 2}O{sub 2} than ZnO@APTMS and ZnO:Cu@APTMS QDs probably via mechanisms associating photo-induced charge carriers and Fenton reactions. In cytotoxicity experiments conducted in the dark or under light exposure, ZnO@APTMS/Cu QDs appeared slightly more deleterious to Escherichia coli cells than the two other QDs, therefore pointing out the importance of the presence of Cu{sup 2+} ions at the periphery of the nanocrystals. On the other hand, with the lack of photo-induced toxicity, it can be inferred that ROS production cannot explain the cytotoxicity associated to the QDs. Our study demonstrates that both the production of ROS from ZnO QDs and their toxicity may be enhanced by chemisorbed Cu{sup 2+} ions, which could be useful for medical or photocatalytic applications.

  20. Alkaline vapor oxidation synthesis and electrocatalytic activity toward glucose oxidation of CuO/ZnO composite nanoarrays

    Science.gov (United States)

    Soejima, Tetsuro; Takada, Kohei; Ito, Seishiro

    2013-07-01

    CuO/ZnO nanocomposite materials have attracted widespread attention because of their scientific and technological importance as, for example, photocatalysts, gas and humidity sensors, catalysts for H2 production and organic synthesis, and solar cells. High-temperature and/or complicated multistep processes are usually used to prepare these composites. Here we demonstrate a low-temperature and facile one-step synthesis of CuO nanoflowers/ZnO nanorods composite arrays via an alkaline vapor oxidation process. The CuO/ZnO composite nanoarrays show high electrocatalytic activity toward glucose oxidation.

  1. Test of experimental set-ups for electrodialytic removal of Cu, Zn, Pb and Cd from different contaminated harbour sediments

    DEFF Research Database (Denmark)

    Nystrøm, Gunvor Marie; Ottosen, Lisbeth M.; Villumsen, Arne

    2005-01-01

    of the sediment slurry, the other without stirring. The removal of heavy metals was highest in the non-calcareous sediment, where 94% Cd, 91% Zn and 73% Cu were removed after 24 days. The highest removal obtained for the calcareous sediment was 81% Cd, 76% Zn, 75% Pb and 53% Cu after 21 days, with stirred...... was the most stable in these experiments, and thus, the stirred set-up is the best choice for experimental set-up. The order in which the heavy metals were removed from the harbour sediments was Cd>Zn>Pb>Cu....

  2. Local structure and magnetization of ferromagnetic Cu-doped ZnO films: No magnetism at the dopant?

    Energy Technology Data Exchange (ETDEWEB)

    Vachhani, P.S., E-mail: prashjdg@gmail.com [School of Physics, University of Hyderabad, Hyderabad 500 046 (India); Department of Physics, University of Trento, 38123 Povo, Trento (Italy); Šipr, O. [Institute of Physics AS CR v. v. i., Cukrovarnická 10, Prague (Czech Republic); Bhatnagar, A.K. [School of Physics, University of Hyderabad, Hyderabad 500 046 (India); School of Engineering Sciences & Technology, University of Hyderabad, Hyderabad 500 046 (India); Ramamoorthy, R.K. [Department of Physics, University of Trento, 38123 Povo, Trento (Italy); School of Engineering Sciences & Technology, University of Hyderabad, Hyderabad 500 046 (India); Choudhary, R.J.; Phase, D.M. [UGC-DAE Consortium for Scientific Research, Khandwa Road, Indore 452 017 (India); Dalba, G. [Department of Physics, University of Trento, 38123 Povo, Trento (Italy); Kuzmin, A. [Institute of Solid State Physics, University of Latvia, LV-1063 Riga (Latvia); Rocca, F. [IFN-CNR, Institute for Photonics and Nanotechnologies, Unit “FBK-Photonics” of Trento, 38123 Povo, Trento (Italy)

    2016-09-05

    Relationship between magnetism and structure of Cu-doped ZnO was investigated at macroscopic and microscopic levels. Thin Zn{sub 1−x}Cu{sub x}O films (x = 0.02, 0.04, 0.07 and 0.10) were prepared by a pulsed laser deposition and characterized via superconducting quantum interference device (SQUID) magnetometry, high-resolution x-ray diffraction, and Cu K-edge and Zn K-edge x-ray absorption, x-ray linear dichroism and x-ray circular magnetic dichroism spectroscopy. Even though the samples exhibit room-temperature ferromagnetism with magnetization that increases with Cu concentration, we did not detect signatures of local magnetic moments associated with Cu atoms, as evidenced by the lack of any XMCD signal. The host ZnO wurtzite lattice is not significantly altered by the addition of Cu. At the same time, most of the Cu atoms are not incorporated into the wurtzite lattice but rather have a CuO-like coordination. These results indicate that ferromagnetism of the investigated Zn{sub 1−x}Cu{sub x}O films is not directly linked to the doping atoms but rather is due to some other changes which have been introduced to the host ZnO by the dopants. - Highlights: • Ferromagnetic Cu doped ZnO films have been prepared. • Magnetic moments are not actually associated with Cu atoms. • Observed ferromagnetism can be devoted to doping induced yet unspecified changes.

  3. Cu isotope variability in Bavariás largest Cu-Zn deposit in Kupferberg (NE Bavaria, Germany)

    Science.gov (United States)

    Höhn, Stefan; Frimmel, Hartwig E.; Debaille, Vinciane; Debouge, Wendy

    2016-04-01

    Kupferberg, a small town c. 15 km northeast of Kulmbach, owns its existence to Bavaria's largest Cu-Zn deposit, which was mined intermittently from the 13th to the 19th century. The deposit is located in the Saxothuringian Zone of the Variscan basement in northeastern Bavaria. It is positioned between the allochthonous Münchberg metamorphic complex in the east and a major northwest-southeast tending regional fault zone, the "Franconian Lineament", in the west. The deposit is hosted by an Early Palaeozoic volcano-sedimentary succession of the Randschiefer Formation (RF) and consists of a northwest-southeast directed string of several stratiform, sulfide-rich ore lenses. These lenses show a remarkably simple mineralogy dominated by quartz, carbonate, pyrite and chalcopyrite with minor amounts of sphalerite and chlorite. The genesis of the Cu-Zn mineralization has remained speculative. A purely syngenetic model, supported by the generally laminated appearance of the ore, has to be questioned because of the ore lenses occurring in different tectonic units. Urban & Vaché (1972) proposed supergene enrichment between the Cretaceous and the Tertiary as most critical. To test such a supergene versus hypogene Cu-mineralization, we investigated the Cu isotopic composition of primary and secondary Cu phases as well as the trace element distribution in three pyrite generations. The pyrite generation that is coeval with the principal Cu-mineralization in the form of chalcopyrite has Co/Ni ratios (on average 35) typical of hydrothermal, possibly metamorphic, formation. Chalcopyrite, present at highly variable modal proportions, yielded a narrow range in δ65Cu from -0.26 to 0.36 ‰Ḃoth the absolute values and the narrow range are similar to the δ65Cu range known for hydrothermal chalcopyrite in crustal rocks (Markl et al. 2006). Metamorphism has been shown to further restrict the range in δ65Cu (Ikehata et al. 2011) - an effect that might be applicable to Kupferberg. In

  4. Doping dependent room-temperature ferromagnetism and structural properties of dilute magnetic semiconductor ZnO:Cu 2+ nanorods

    Science.gov (United States)

    Sharma, Prashant K.; Dutta, Ranu K.; Pandey, Avinash C.

    2009-12-01

    Copper doped ZnO nanoparticles were synthesized by the chemical technique based on the hydrothermal method. The crystallite structure, morphology and size were determined by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM) for different doping percentages of Cu 2+ (1-10%). TEM/SEM images showed formation of uniform nanorods, the aspect ratio of which varied with doping percentage of Cu 2+. The wurtzite structure of ZnO gradually degrades with the increasing Cu 2+ doping concentration and an additional CuO associated diffraction peak was observed above 8% of Cu 2+ doping. The change in magnetic behavior of the nanoparticles of ZnO with varying Cu 2+ doping concentrations was investigated using a vibrating sample magnetometer (VSM). Initially these nanoparticles showed strong room-temperature ferromagnetic behavior, however at higher doping percentage of copper the ferromagnetic behavior was suppressed and paramagnetic nature was enhanced.

  5. High and stable photoelectrochemical activity of ZnO/ZnSe/CdSe/Cu(x)S core-shell nanowire arrays: nanoporous surface with Cu(x)S as a hole mediator.

    Science.gov (United States)

    Ouyang, Wei-Xin; Yu, Yu-Xiang; Zhang, Wei-De

    2015-06-14

    Advanced materials for electrocatalytic and photoelectrochemical water splitting are key for taking advantage of renewable energy. In this study, ZnO/ZnSe/CdSe/Cu(x)S core-shell nanowire arrays with a nanoporous surface were fabricated via ion exchange and successive ionic layer adsorption and reaction (SILAR) processes. The ZnO/ZnSe/CdSe/Cu(x)S sample displays a high photocurrent density of 12.0 mA cm(-2) under AM 1.5G illumination, achieves the highest IPCE value of 89.5% at 500 nm at a bias potential of 0.2 V versus Ag/AgCl, and exhibits greatly improved photostability. The functions of the ZnSe, CdSe, and Cu(x)S layers in the ZnO/ZnSe/CdSe/Cu(x)S heterostructure were clarified. ZnSe is used as a passivation layer to reduce the trapping and recombination of charge carriers at the interfaces of the semiconductors. CdSe functions as a highly efficient visible light absorber and builds heterojunctions with the other components to improve the separation and transportation of the photoinduced electrons and holes. Cu(x)S serves as a passivation layer and an effective p-type hole mediator, which passivates the defects and surface states of the semiconductors and forms p-n junctions with CdSe to promote the hole transportation at the semiconductor-electrolyte interface. The nanoporous surface of the ZnO/ZnSe/CdSe/Cu(x)S core-shell nanowire arrays, together with the tunnel transportation of the charge carriers in the thin films of ZnSe and CdSe, also facilitates the kinetics of photoelectrochemical reactions and improves the optical absorption as well.

  6. Structural and optical properties of Y, Cu co-doped ZnO nanoparticles by sol-gel method

    Science.gov (United States)

    Anandan, S.; Muthukumaran, S.; Ashokkumar, M.

    2014-10-01

    Zn.96-xY.04CuxO (x = 0, 0.05, 0.10 and 0.15) nanoparticles were successfully synthesized employing simple sol-gel method. Hexagonal wurtzite structure of the synthesized samples was not affected by Cu-doping. CuO phase was induced after Cu = 5% and it was increased by Cu-doping. The change in crystal size was discussed based on compressive stress, lattice volume and bond length. The chemical stoichiometry of Zn, Cu, Y and O was confirmed by energy dispersive X-ray spectra. The increased oxygen percentage from 57.88 (Cu = 5%) to 64.53% (Cu = 15%) by Cu-doping proved the existence of CuO and oxygen rich phase. The lower absorption and high transmittance in visible region observed at Cu = 5% described the good optical quality of the sample with low scattering or absorption losses which leads to the industrial applications especially as transparent electrode. The high energy gap at Cu = 5% could be attributed to the poor crystallinity of the sample. The red shift in energy gap after Cu = 5% was explained by the p-d spin-exchange interactions between the band electrons and the localized d electrons of Cu2+ ions. The change in intensity and peak position of infrared (IR) peaks confirmed the presence of Cu in Znsbnd Ysbnd O lattice and also expressed the perturbation generated by Cu in Znsbnd Ysbnd O lattice.

  7. Synthesis and characterization of Ce, Cu co-doped ZnS nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Harish, G.S.; Sreedhara Reddy, P., E-mail: psreddy4@gmail.com

    2015-09-15

    Ce, Cu co-doped ZnS nanoparticles were prepared at room temperature using a chemical co-precipitation method. The prepared nanoparticles were characterized by X- ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive analysis of X-rays (EDAX), diffuse reflectance spectroscopy (DRS), photoluminescence (PL) and high resolution Raman spectroscopic techniques. Transmission electron microscopy (TEM) and X-ray diffraction studies showed that the diameter of the particles was around 2–3 nm. Broadened XRD peaks revealed the formation of nanoparticles with a face centered cubic (fcc) structure. DRS studies confirmed that the band gap increased with an increase in the dopant concentration. The Raman spectra of undoped and Ce, Cu ions co-doped ZnS nanoparticles showed longitudinal optical mode and transverse optical mode. Compared with the Raman modes (276 and 351 cm{sup −1}) of undoped ZnS nanoparticles, the Raman modes of Ce, Cu co- doped ZnS nanoparticles were slightly shifted towards lower frequency. PL spectra of the samples showed remarkable enhancement in the intensity upon doping.

  8. Photoelectric properties of Cu2ZnSnS4 thin films deposited by thermal evaporation

    Science.gov (United States)

    Xinkun, Wu; Wei, Liu; Shuying, Cheng; Yunfeng, Lai; Hongjie, Jia

    2012-02-01

    Sn/Cu/ZnS precursor were deposited by evaporation on soda lime glass at room temperature, and then polycrystalline thin films of Cu2ZnSnS4 (CZTS) were produced by sulfurizing the precursors in a sulfur atmosphere at a temperature of 550 °C for 3 h Fabricated CZTS thin films were characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, ultraviolet-visible-near infrared spectrophotometry, the Hall effect system, and 3D optical microscopy. The experimental results show that, when the ratios of [Cu]/([Zn] + [Sn]) and [Zn]/[Sn] in the CZTS are 0.83 and 1.15, the CZTS thin films possess an absorption coefficient of larger than 4.0 × 104 cm-1 in the energy range 1.5-3.5 eV, and a direct band gap of about 1.47 eV. The carrier concentration, resistivity and mobility of the CZTS film are 6.98 × 1016 cm-3, 6.96 Ω·cm, and 12.9 cm2/(V·s), respectively and the conduction type is p-type. Therefore, the CZTS thin films are suitable for absorption layers of solar cells.

  9. Photoelectric properties of Cu2ZnSnS4 thin films deposited by thermal evaporation

    Institute of Scientific and Technical Information of China (English)

    吴新坤; 柳伟; 程树英; 赖云锋; 贾宏杰

    2012-01-01

    Sn/Cu/ZnS precursor were deposited by evaporation on soda lime glass at room temperature,and then polycrystalline thin films of Cu2ZnSnS4 (CZTS) were produced by sulfurizing the precursors in a sulfur atmosphere at a temperature of 550 ℃ for 3 h.Fabricated CZTS thin films were characterized by X-ray diffraction,energy dispersive X-ray spectroscopy,ultraviolet-visible-near infrared spectrophotometry,the Hall effect system,and 3D optical microscopy.The experimental results show that,when the ratios of [Cu]/([Zn] + [Sn]) and [Zn]/[Sn] in the CZTS are 0.83 and 1.15,the CZTS thin films possess an absorption coefficient of larger than 4.0 × 104 cm-1 in the energy range 1.5-3.5 eV,and a direct band gap of about 1.47 eV.The carrier concentration,resistivity and mobility of the CZTS film are 6.98 × 1016 cm-3,6.96 Ω.cm,and 12.9 cm2/(V.s),respectively and the conduction type is p-type.Therefore,the CZTS thin films are suitable for absorption layers of solar cells.

  10. Cu and Zn Speciation in an Acid Soil Amended with Alkaline Biosolids

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Fractionation of metals in a granite-derived acid sandy loam soil amended with alkaline-stabilised sewage sludge biosolids was conducted in order to assess metal bioavailability and environmental mobility. Soil solution was extracted by a centrifugation and filtration technique. Metal speciation in the soil solution was determined by a cation exchange resin method. Acetic acid and EDTA extracting solutions were used for extraction of metals in soil solid surfaces. Metal distribution in different fractions of soil solid phase was determined using a three-step sequential extraction scheme. The results show that the metals in the soil solution existed in different fractions with variable lability and metals in the soil solid phase were also present in various chemical forms with potentially different bioavailability and environmental mobility. Alkalinestabilised biosolids could elevate solubility of Cu and proportion of Cu in organically complexed fractions both in soil liquid and solid phases, and may therefore increase Cu mobility. In contrast, the biosolids lowered the concentrations of water-soluble Zn (labile fraction) and exchangeable Zn and may hence decrease bioavailability and mobility of Zn. However, Fe and Mn oxides bound and organic matter bound fractions are likely to be Zn pools in the sludge-amended soil. These consequences possibly result from the liming effect and metal speciation of the sludge product and the difference in the chemistry between the metals in soil.

  11. Divacancy complexes induced by Cu diffusion in Zn-doped GaAs

    Science.gov (United States)

    Elsayed, M.; Krause-Rehberg, R.; Korff, B.; Ratschinski, I.; Leipner, H. S.

    2013-08-01

    Positron annihilation spectroscopy was applied to investigate the nature and thermal behavior of defects induced by Cu diffusion in Zn-doped p-type GaAs crystals. Cu atoms were intentionally introduced in the GaAs lattice through thermally activated diffusion from a thin Cu capping layer at 1100 °C under defined arsenic vapor pressure. During isochronal annealing of the obtained Cu-diffused GaAs in the temperature range of 450-850 K, vacancy clusters were found to form, grow and finally disappear. We found that annealing at 650 K triggers the formation of divacancies, whereas further increasing in the annealing temperature up to 750 K leads to the formation of divacancy-copper complexes. The observations suggest that the formation of these vacancy-like defects in GaAs is related to the out-diffusion of Cu. Two kinds of acceptors are detected with a concentration of about 1016 - 1017 cm-3, negative ions and arsenic vacancy copper complexes. Transmission electron microscopy showed the presence of voids and Cu precipitates which are not observed by positron measurements. The positron binding energy to shallow traps is estimated using the positron trapping model. Coincidence Doppler broadening spectroscopy showed the presence of Cu in the immediate vicinity of the detected vacancies. Theoretical calculations suggested that the detected defect is VGaVAs-2CuGa.

  12. Analysis of Cu Diffusion in ZnTe-Based Contacts for Thin-Film CdS/CdTe Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Narayanswamy, C. (Department of Physics & Astronomy, University of Toledo); Gessert, T. A. and Asher, S. E. (National Renewable Energy Laboratory)

    1998-10-27

    Ohmic contacts to thin-film CdS/CdTe photovoltaic devices have been formed using a two-layer contact interface of undoped ZnTe (ZnTe) and Cu-doped ZnTe (ZnTe:Cu), followed by Ni or Ti as an outer metallization. Secondary ion mass spectroscopy (SIMS) is used to study Cu diffusion within this back-contact structure, and also, to monitor Cu diffusion from the contact into the CdTe. When Ni metallization is used, the ZnTe:Cu layer becomes increasingly depleted of Cu, and Ni diffusion into the ZnTe:Cu increases as the contact deposition temperature increases from 100 C to 300 C. Cu depletion is not observed when Ni is replaced with Ti. Diffusion of Cu from the ZnTe:Cu layer into the ZnTe layer also increases with contact deposition temperature, and produces a buildup of Cu at the ZnTe/CdTe interface. High-mass resolution SIMS indicates that, although Cu levels in the CdTe remain low, Cu diffusion from the contact proceeds into the CdTe layer and toward the CdTe/CdS junction region.

  13. Assessment of the Bioavailability of Cu, Pb, and Zn through Petunia axillaris in Contaminated Soils

    Directory of Open Access Journals (Sweden)

    Lydia Bondareva

    2014-01-01

    Full Text Available Heavy metals are potentially toxic to human life and the environment. Metal toxicity depends on chemical associations in soils. For this reason, determining the chemical form of a metal in soils is important to evaluate its mobility and the potential accumulation. The aim of this examination is to evaluate the accumulation potential of Petunia x hybrida as a flower crop for three metals, namely, copper (Cu, lead (Pb, and nickel (Ni. Trace metals (Zn, Cu, and Pb in the soils were partitioned by a sequential extraction procedure into H2O extractable (F1, 1 M CH3COONa extractable (F2. Chemical fractionation showed that F1 and F2 fraction of the metals were near 1% and residue was the dominant form for Zn, Cu, and Pb in all samples. Using fluorescence method allowed us to estimate condition of the plants by adding metals. As result of plant and soil analysis, we can conclude that Petunia has Cu, Zn, and Ni tolerance and accumulation. Therefore, Petunia has the potential to serve as a model species for developing herbaceous, ornamental plants for phytoremediation.

  14. Relation of Zn, Fe, Cu and Mn between progenies of mate-tree and soil

    Directory of Open Access Journals (Sweden)

    Josiane Cava Guimarães

    2014-06-01

    Full Text Available The mate tea tree (Ilex Paraguariensis St. Hil. has considerable growth in acid a low fertility soils. The knowledge of soil and plant relation will contribute to genetic improvement programs, as highly capable progenies in nutrient acquisition may be selected. The objective of this study was to evaluate the interference of provenance and, or progenies, in relations established among the extractable contents of Zn, Fe, Cu and Mn, via Mehlich-1 (1:10; and EDTA (1%, with the corresponding contents in the mate tea tree leaves. In the experiment two provenances, Ivaí-PR and Barão de Cotegipe-RS, with five progenies each considered as treatments. The samples were distributed in four randomized blocks, totalizing 120 plant leaf samples, related to 120 soil samples of a Red Distrophic Latosol. The results were analyzed and fitted in regression equations. In Ivaí provenance Zn and Mn from the soil correlated with their contents in the leaves for progeny 04, for both extracts. For provenances 08 and 10, soil Mn via EDTA correlated with leaf Mn contents, while via Mehlich-1 only for progeny 10. In the provenance of Barão de Cotegipe, the correlations between soil and leaves for Zn, Fe and Cu occurred for the EDTA extract in the progenies 61, 65 and 69 respectively. For Mn and Cu, via Melich-1 the correlations occurred for progenies 53 and 69 respectively, and still for Cu, via EDTA, for progeny 53.

  15. Synthesis, XRD, TEM, EPR, and Optical Absorption Spectral Studies of CuZnO2 Nanocompound

    Directory of Open Access Journals (Sweden)

    T. Ravindra Reddy

    2014-01-01

    Full Text Available Synthesis of nano CuZnO2 compound is carried out by thermal decomposition method. The crystalline phase of the material is characterized by XRD. The calculated unit cell constants are a=3.1 Å and c=3.4786 Å and are of tetragonal structure. The unit cell constants are different from wurtzite (hexagonal which indicate that a nanocompound is formed. Further TEM images reveal that the metal ion is in tetragonal structure with oxygen ligands. The prepared CuZnO2 is then characterized for crystallite size analysis by employing transmission electron microscopy (TEM. The size is found to be 100 nm. Uniform bright rings are noticed in the TEM picture suggesting that the nanocrystals have preferential instead of random orientations. The selected-area electron diffraction (SAED pattern clearly indicates the formation of CuO-ZnO nanocompound. The nature of bonding is studied by electron paramagnetic resonance (EPR. The covalency character is about 0.74 and thus the compound is electrically less conductive. Optical absorption spectral studies suggest that Cu(II is placed in tetragonal elongation crystal field. The spin-orbit coupling constant, λ, is calculated using the EPR and optical absorption spectral results suggest some covalent bond between metal and ligand. Near infrared (NIR spectra are due to hydroxyl and water fundamentals.

  16. Modification of ZnO Thin Films by Ni, Cu, and Cd Doping*1

    Science.gov (United States)

    Jiménez-González, A. E.

    1997-02-01

    With the propose of investigating the effect of transition elements in ZnO thin films prepared by the Successive Ion Layer Adsorption and Reaction (SILAR) technique, the deposition solutions were chemically impurified with Ni, Cu, and Cd, as elements of the Ib, IIb, and VIIIa groups. X-ray fluorescence (XRF) analyses confirm that the impurification with Ni and Cu in fact took place but the impurification with Cd did not, while the XRD analyses show that foras preparedand Ni-impurified annealed films, the crystallites are almost oriented along thecaxis. The electrical properties of the ZnO films were also modified with the impurification. After annealing in air (450°C) the dark conductivity of the films was increased in the case of Ni and Cd impurification up to 1.80×10-3and 1.86×10-2[Ω cm]-1, respectively, but it decreased drastically in the case of Cu to 5.51×10-7[Ω cm]-1, as referred to the dark conductivity (1.86×10-4[Ω cm]-1) of the pure ZnO sample. The measured activation energy for the electrical conductivity of the modified ZnO thin films is 55 meV for the Ni modification, indicating the existence of donor levels. On the other hand, the Cu modification increases the activation energy up to 132 meV, which is higher than the activation energy for pure ZnO thin films (98 meV).

  17. Enhanced uptake of As, Zn, and Cu by Vetiveria zizanioides and Zea mays using chelating agents.

    Science.gov (United States)

    Chiu, K K; Ye, Z H; Wong, M H

    2005-09-01

    Vetiveria zizaniodes (vetiver) is commonly known for its effectiveness in soil and sediment erosion control. It can tolerate to extreme soil conditions and produce a high biomass even growing in contaminated areas. Zea mays (maize) can also produce a very high biomass with a fast growth rate and possesses some degree of metal tolerance. A greenhouse study was conducted to investigate the feasibility of using vetiver and maize for remediation of arsenic (As)-, zinc (Zn-), and copper (Cu)-amended soils and evaluate the effects of chelating agents on metal uptake by these plants. Vetiver had a better growth (dry weight yield of root and shoot) than maize under different treatment conditions. The effects of different chelating agents on As, Zn, and Cu extraction from soil to soil solution were studied. Among the nine chelating agents used, it was noted that 20 mmol NTA could maximize As and Zn bioavailability, while 20 mmol HEIDA could maximize Cu bioavailability in the soil solution. The surge time in maximizing metal uptake ranged from 16 to 20 days which indicated that timing on plant harvest was an important factor in enhanced metal accumulation. In general, vetiver was a more suitable plant species than maize in terms of phytoextraction of metals from metal-contaminated soil. Application of NTA in As-amended soil and HEIDA in Cu-amended soil at the rate of 20 mmol kg(-1) increased 3-4-fold of As and Cu in shoot of both plants, whereas application of NTA (20 mmol kg(-1)) increased 37- and 1.5-fold of Zn accumulation in shoot of vetiver and maize, respectively. The potential environmental risk of metal mobility caused by chelating agents used for phytoextraction should not be overlooked.

  18. [Investigation of As, Cu and Zn species and concentrations in animal feeds].

    Science.gov (United States)

    Yao, Li-Xian; Huang, Lian-Xi; Jiang, Zong-Yong; He, Zhao-Huan; Zhou, Chang-Min; Li, Guo-Liang

    2013-02-01

    Seventy chicken and seventy-six pig feeds were collected from the feed stores in Guangdong province, and the species and concentrations of As, Cu and Zn were determined. We also examined the stability of roxarsone (ROX), one of the most widely used organoarsenical additives, either in the additive or in the feed at room temperature. The results showed that, averagely, the chicken and pig feeds contained 3.6 and 6.5 mg.kg-1 (As), 18.2 and 119.4 mg.kg-1 (Cu),and 124.6 and 486.2 mg.kg-1 (Zn), respectively. The excessive dosages of As, Cu and As in animal feeds will lead to higher residue of As, Cu and Zn in animal manures. Based on the national limit criteria for feed or feed additive, it was supposed that organoarsenicals had been used, only few feed samples exceeded the As limit, however, the excessive Cu and Zn in pig feeds were much more common. Organoarsenicals were found in 25.4% of the total feed samples, and As(Ill) and As(V) were the two most commonly detected As impurities in feeds bearing organoarsenicals. The mean detectable ROX and arsenilic acid were 7.0 and 21.2 mg.kg-1, respectively. Organoarsenicals were detectable in 24. 3% of the chicken feed samples and 26. 3% of the pig feed samples. Moreover, ROX was commonly used in chicken feeds, while p-ASA in pig feeds. ROX and the inorganic As impurities, either in the commercial additive or in the feed, remained stable for at least 30 days at room temperature, indicating the higher As impurities in feeds probably originated from the As impurities in organoarsenical additives. This is a new As exposure pathway for the producer and user of organoarsenicals and feeds amending organoarsenicals.

  19. Effect and Properties of Surface-Modified Copper Doped ZnO Nanoparticles (Cu:ZnO NPs on Killing Curves of Bacterial Pathogens

    Directory of Open Access Journals (Sweden)

    Enayatollah Kalantar

    2015-10-01

    Full Text Available Background: The current study aimed to determine the effect and properties of surface-modified copper doped Cu:ZnO NPs on killing curves of bacterial pathogens.Methods:  Preparation  of  in  situ  surface-modified  copper  doped  ZnOnanoparticles (Cu:ZnO NPs was done according to standard procedure.Assay for antimicrobial activity of Cu:ZnO NPs against bacterial pathogens was carried out based on disc diffusion method. Determination of shelf life, thermal and pH stability of antibacterial activity of Cu:ZnO NPs was done and residual activity was determined against the target cultures.Results: FTIR spectra indicate that the nanomaterials synthesized have higher peak intensity compared with reagent grade ZnO. According to the SEM image the nanoparticles synthesized have different size and heterogeneous morphology.  400  ppm  of  Cu:ZnO  NPs  gave  zones  of  inhibition  with diameters of 9.0 – 16 mm against the target cultures. Amongst the target cultures, Escherchia coli was the most sensitive to the Cu:ZnO NPs inhibition zone diameter 16 mm; whereas, 9 mm wide inhibition zone was obtained against  Staphylococcus  aureus. The  Cu:ZnO  NPs  was  fairly stable  for a period of 60 days at room temperature (RT showing lost of only 20% and30%     antibacterial  activity  as  tested  against  E.  coli  and  S.  aureus, respectively. The Cu:ZnO NPs was quite stable at this pH and temperaturerange tested against both E. coli and S. aureus.Conclusion: Surface-modified copper doped Cu:ZnO NPs have significant potential for their usefulness as antibacterial agents.

  20. Anharmonicity effects in Cu-doped ZnO nanocombs by temperature-dependent Raman scattering

    Science.gov (United States)

    Kong, J. F.; Fan, D. H.; Shen, W. Z.

    2016-09-01

    Micro-Raman spectra of E 2(high) phonon mode in Cu-doped ZnO nanocombs have been presented in detail with different Cu compositions under the temperature ranging from 83 to 443 K grown by a simple catalyst-free chemical vapor deposition method. The alloy disorder effect has been investigated by analyzing the asymmetric broadening of E 2(high) phonon mode and Cu-induced localized vibration mode at room temperature. In addition, we resort to a theory model including the lattice thermal expansion and anharmonic phonon-phonon interaction, which can well describe the temperature dependence of Raman shift and linewidth of E 2(high) phonon. In combining with the theory model, we have revealed an increasing anharmonic effect on the Raman shift and linewidth behaviors with increasing Cu composition. Furthermore, it is found that the lifetime of E 2(high) phonon mode shortens with enhancing the anharmonicity.

  1. Effect of γ-rays irradiation on the structural, magnetic, and electrical properties of Mg-Cu-Zn and Ni-Cu-Zn ferrites

    Science.gov (United States)

    Assar, S. T.; Abosheiasha, H. F.; El Sayed, A. R.

    2017-01-01

    Nanoparticles of Ni0.35Cu0.15Zn0.5Fe2O4 and Mg0.35Cu0.15Zn0.5Fe2O4, have been synthesized by citrate precursor method. Then some of the prepared samples have been irradiated by γ-rays of 60Co radioactive source at room temperature with doses of 1 Mrad and 2 Mrad, at a dose rate of 0.1 Mrad/h to study the effect of γ-rays irradiation on some structural, magnetic and electrical properties of the samples. The X-ray diffraction analysis (XRD), transmission electron microscopy, Fourier transform infrared spectroscopy and vibrating sample magnetometer measurements have been used to investigate the samples. The XRD results show that the irradiation has caused a decrease in the crystallite size and the measured density and an increase in the porosity, specific surface area, and microstrain in the case of Ni-Cu-Zn ferrite whereas in the case of Mg-Cu-Zn ferrite the reverse trend has been noticed. The lattice constant of the investigated samples has been increased with the increase of irradiation due to the conversion of Fe3+ (0.67 Å) to Fe2+ (0.76 Å). The magnetization results show an increase in saturation and remnant magnetizations for the two prepared ferrites after γ-rays irradiation. The main reason of this behavior is most probably due to the redistribution of the cations between A and B sites. The cation distribution has been proposed such that the values of theoretical and experimental magnetic moment are identical and increase as the magnetization increases. Moreover, a theoretical estimation of the lattice constant has been calculated on the basis of the proposed cation distribution for each sample and compared with the corresponding experimental values obtained by XRD analysis; where they have been found in a good agreement with each other. This can be considered as another confirmation of the validity of the cation distribution. Moreover, the cation distribution is thought to play an important role in increasing the values of dc conductivity of all samples

  2. Temperature dependence of core loss in cobalt substituted Ni-Zn-Cu ferrites

    Energy Technology Data Exchange (ETDEWEB)

    Lucas, A., E-mail: ant50_lucas@yahoo.f [THALES R and T, Campus Polytechnique, 1 Avenue Augustin Fresnel, 91767 Palaiseau (France); SATIE, ENS de Cachan, 61 Avenue du President Wilson, 94235 Cachan (France); Lebourgeois, R. [THALES R and T, Campus Polytechnique, 1 Avenue Augustin Fresnel, 91767 Palaiseau (France); Mazaleyrat, F. [SATIE, ENS de Cachan, 61 Avenue du President Wilson, 94235 Cachan (France); Laboure, E. [SATIE, ENS de Cachan, 61 Avenue du President Wilson, 94235 Cachan (France); LGEP, SUPELEC, Plateau de Moulon, 11 rue Joliot-Curie, 91192 Gif Sur Yvette (France)

    2011-03-15

    The temperature dependence of core loss in cobalt substituted Ni-Zn-Cu ferrites was investigated. Co{sup 2+} ions are known to lead to a compensation of the magneto-crystalline anisotropy in Ni-Zn ferrites, at a temperature depending on the cobalt content and the Ni/Zn ratio. We observed similar behaviour in Ni-Zn-Cu and it was found that the core loss goes through a minimum around this magneto-crystalline anisotropy compensation. Moreover, the anisotropy induced by the cobalt allowed a strong decrease of core loss, a ferrite having a core loss of 350 mW/cm{sup 3} at 80 {sup o}C was then developed (measured at 1.5 MHz and 25 mT). This result represents an improvement of a factor 4 compared to the state of art Ni-Zn ferrites. - Research highlights: > Low temperature sintering ferrite. > Improvement of the core loss of high frequency ferrites. > Power ferrites working at high temperature.

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

    Directory of Open Access Journals (Sweden)

    Leila Farzin

    2014-02-01

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

  4. Fabrication of Cu{sub 2}ZnSnS{sub 4} screen printed layers for solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Zhihua; Wang, Yanyan; Xu, Dong; Zhang, Yafei [National Key laboratory of Micro/Nano Fabrication Technology, Key Laboratory for Thin film and Microfabrication of Ministry of Education, Research Institute of Micro/Nano Science and Technology, Shanghai Jiaotong University, Shanghai (China)

    2010-12-15

    Cu{sub 2}ZnSnS{sub 4} layers have been successfully fabricated on flexible polyimide substrates by screen printing. The microparticles of Cu{sub 2}ZnSnS{sub 4}, which is the main raw material for preparing screen printing paste, were prepared by wet ball milling and sintering methods. X-ray diffraction characterization results show the screen printed Cu{sub 2}ZnSnS{sub 4} layers were well indexed to single phase Cu{sub 2}ZnSnS{sub 4}. Scanning electronic microscopy images show the diameters and lengths of the as-prepared Cu{sub 2}ZnSnS{sub 4} microparticles are about 30-50 and 150-200 nm, respectively. The bandgap, sheet resistance, carrier concentration, and Hall mobility of the screen printed Cu{sub 2}ZnSnS{sub 4} layers were about 1.49 eV, 2.42 x 10{sup 3} {omega}, 3.81 x 10{sup 18} cm{sup -3}, and 12.61 cm{sup 2} V{sup -1} s{sup -s} at 25 C, respectively. To evaluate the photoresponse of the screen printed Cu{sub 2}ZnSnS{sub 4} layers, complete photovoltaic cells with the structure of polyimide/Mo/Cu{sub 2}ZnSnS{sub 4}/CdS/ZnO:Al/Al-grid were further fabricated. The short-circuit current density, open-circuit voltage, fill factor, and efficiency of a typical photovoltaic cell with an active area of 0.15 cm{sup 2} were 4.76 mA/cm{sup 2}, 386 mV, 0.27, and 0.49%, respectively. (author)

  5. Zn(II) ions substantially perturb Cu(II) ion coordination in amyloid-β at physiological pH.

    Science.gov (United States)

    Silva, K Ishara; Saxena, Sunil

    2013-08-15

    The interaction of Cu(II) and Zn(II) ions with amyloid-β (Aβ) plays an important role in the etiology of Alzheimer's disease. We describe the use of electron spin resonance (ESR) to measure metal-binding competition between Cu(II) and Zn(II) in amyloid-β at physiological pH. Continuous wave ESR measurements show that the affinity of Cu(II) toward Aβ(1-16) is significantly higher than that of Zn(II) at physiological pH. Importantly, of the two known Cu(II) coordination modes in Aβ, component I and component II, Zn(II) displaces Cu(II) only from component I. Our results indicate that at excess amounts of Zn(II) component II becomes the most dominant coordination mode. This observation is important as Aβ aggregates in the brain contain a high Zn(II) ion concentration. In order to determine details of the metal ion competition, electron spin echo envelope modulation experiments were carried out on Aβ variants that were systematically (15)N labeled. In the presence of Zn(II), most peptides use His 14 as an equatorial ligand to bind Cu(II) ions. Interestingly, Zn(II) ions completely substitute Cu(II) ions that are simultaneously coordinated to His 6 and His 13. Furthermore, in the presence of Zn(II), the proportion of Cu(II) ions that are simultaneously coordinated to His 13 and His 14 is increased. On the basis of our results we suggest that His 13 plays a critical role in modulating the morphology of Aβ aggregates.

  6. Uptake and accumulation of potentially toxic metals (Zn, Cu and Pb) in soils and plants of Durgapur industrial belt.

    Science.gov (United States)

    Kisku, Ganesh Chandra; Pandey, Poonam; Negi, Mahendra Pratap Singh; Misra, Virendra

    2011-11-01

    Uptake and accumulation of metals in crops may cause possible health risks through food chain. A field survey was conducted to investigate the accumulation of potentially toxic metals contamination in soil and plants irrigated with complexed industrial effluents. Concentration of Zn, Cu and Pb was 205-255,101-130,118-177 microg g(-1) in rhizosphere soils and 116-223, 57-102 and 63-95 microg g(-1) d. wt. in root and 95-186, 44-75 and 27-58 microg g(-1) d. wt. in shoot, respectively. The trend in Cu and Pb was in the order: soil > root > shoot > seed while in Zn it was soil > root > seed > shoot. Roots accumulated a larger fraction of soil Cu (70%) > Zn (67%) > Pb (54%). Bioaccumulation coefficient of soil to root ranged from 51-98 for Zn, 54-85 for Cu and 43-63 for Pb.Analysis of variance showed marginal change in bioaccumulation coefficient, noticed between plants (p > 0.05) while it varied significantly (p shoot > seed/fruit) while decreased between metals from Zn to Pb (Zn > Cu > Pb). Out of the three, two Cu and Pb accumulated to phyotoxic levels while Zn was within threshold limit of phytotoxicity.

  7. Thermoelectric properties of Zn doped Cu{sub 2}SnSe{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Raju, Ch [Department of Physics, Indian Institute of Science, Bangalore 560012 (India); Falmbigl, M.; Rogl, P. [Institute of Physical Chemistry, University of Vienna, Währingerstrasse 42, A-1090 Wien (Austria); Heinrich, P.; Royanian, E.; Bauer, E. [Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstrasse 8-10, A-1040 Wien (Austria); Mallik, Ramesh Chandra, E-mail: rcmallik@physics.iisc.ernet.in [Department of Physics, Indian Institute of Science, Bangalore 560012 (India)

    2014-10-15

    Zn doped ternary compounds Cu{sub 2}Zn{sub x}Sn{sub 1−x}Se{sub 3} (x = 0, 0.025, 0.05, 0.075) were prepared by solid state synthesis. The undoped compound showed a monoclinic crystal structure as a major phase, while the doped compounds showed a cubic crystal structure confirmed by powder XRD (X-Ray Diffraction). The surface morphology and elemental composition analysis for all the samples were studied by SEM (Scanning Electron Microscopy) and EPMA (Electron Probe Micro Analyzer), respectively. SEM micrographs of the hot pressed samples showed the presence of continuous and homogeneous grains confirming sufficient densification. Elemental composition of all the samples revealed an off-stoichiometry, which was determined by EPMA. Transport properties were measured between 324 K and 773 K. The electrical resistivity decreased up to the samples with Zn content x = 0.05 in Cu{sub 2}Zn{sub x}Sn{sub 1−x}Se{sub 3}, and slightly increased in the sample Cu{sub 2}Zn{sub 0.075}Sn{sub 0.925}Se{sub 3}. This behavior is consistent with the changes in the carrier concentration confirmed by room temperature Hall coefficient data. Temperature dependent electrical resistivity of all samples showed heavily doped semiconductor behavior. All the samples exhibit positive Seebeck coefficient (S) and Hall coefficient indicating that the majority of the carriers are holes. A linear increase in Seebeck coefficient with increase in temperature indicates the degenerate semiconductor behavior. The total thermal conductivity of the doped samples increased with a higher amount of doping, due to the increase in the carrier contribution. The total and lattice thermal conductivity of all samples showed 1/T dependence, which points toward the dominance of phonon scattering at high temperatures. The maximum 1/TZT = 0.48 at 773 K was obtained for the sample Cu{sub 2}SnSe{sub 3} due to a low thermal conductivity compared to the doped samples. - Highlights: • In this investigation, the

  8. Optical, phonon and efficient visible and infrared photocatalytic activity of Cu doped ZnS micro crystals

    Science.gov (United States)

    Prasad, Neena; Balasubramanian, Karthikeyan

    2017-02-01

    We report, the enhanced photocatalytic behaviour of Cu doped ZnS micro crystals. ZnS and different concentrations of Cu doped ZnS microcrystals were prepared. X-ray diffraction confirms the crystalline and phase of the particles. Morphology and sizes were studied using Scanning Electron Microscopy (SEM). Recorded optical absorption spectra show a band for around 365 nm for pure ZnS, but there is a broad band in the near infrared regime for the Cu-doped ZnS microcrystals which are attributed to the d-d transitions of Cu2 + ions. Phonon properties of as-prepared samples were investigated using Raman spectroscopy. Present work we investigate the potential of ZnS and Cu doped ZnS as a photocatalyst. For this from the degradation of methylene blue dye in aqueous media the photocatalytic activity of pure and highest doped ZnS samples with the irradiation of white light and infrared, enhanced photocatalytic activity were observed. Mechanism of white light an IR light based photocatalytic activity is explained based on the electron-hole pair production.

  9. Influence of Aging Time on the Properties of Precursors of CuO/ZnO Catalysts for Methanol Synthesis

    Institute of Scientific and Technical Information of China (English)

    Deren Fang; Zhongmin Liu; Shuanghe Meng; Ligang Wang; Lei Xu; Hua Wang

    2005-01-01

    The aging process of pure copper precursors and copper-zinc binary precursors were studied by XRD, TG-DTG and TPR techniques. The catalytic activity and stability of CuO/ZnO were tested using fixed-bed flow reactor, and the physical properties of the catalysts and Cu species were characterized with N2 adsorption and N2O passivation method, respectively. For the Cu-Zn binary system prepared at the precipitating condition of pH=8.0 and temperature=80 ℃, the initial phase was a mixture of copper nitrate hydroxide Cu2(NO3)(OH)3, georgeite and hydrozincite Zn5(CO3)2(OH)6. By increasing the duration of its aging time, the phase of Cu2(NO3)(OH)2 first transited to georgeite, and then interdiffused into Zn5(CO3)2(OH)6 and resulted in two new phases: rosasite (Cu,Zn)2CO3(OH)2 and aurichalcite (Zn,Cu)5(CO3)2(OH)6. The former phase was much easier to be formed than the latter one,while the latter phase was more responsible for the activity of methanol synthesis than the former one. It is found that the composition and structure of the precursors altered obviously after the colour transition point. The experimental results showed that methanol synthesis is a structure-sensitive catalytic reaction.

  10. Differential influences of Cu and Zn chronic exposure on Cd and Hg bioaccumulation in an estuarine oyster.

    Science.gov (United States)

    Liu, Fengjie; Wang, Wen-Xiong

    2014-03-01

    In this study, the effects of Cu and Zn exposure, alone and in combination, on the bioaccumulation of Cd and Hg were investigated in an estuarine oyster Crassostrea hongkongensis under different salinity gradients. We showed that Zn, but not Cu, exposure significantly enhanced the Cd bioaccumulation. In contrast, both Cu and Zn exposure significantly enhanced the Hg bioaccumulation. Combined exposure and salinity did not affect the metal interactions in oysters. The increased tissue concentrations of Cd or Hg were associated with their increased storage in inducible metal-binding ligands (e.g. metallothionein-like proteins, MTLP) by Cu/Zn exposure. The differential roles of Cu and Zn exposure in Cd and Hg bioaccumulation resulted from their contrasting ligand induction and affinities. Analysis of field collected oysters indicated that Cu/Zn exposure was a significant contributor to tissue concentrations of Cd, Cu and Hg. Overall, biochemical/physiological changes of the animals chronically exposed to metal stressors played a key role in affecting tissue concentrations of other metals. One metal's ability to enhance the bioaccumulation of other metals depended upon the relative affinities of the metals for MTLP.

  11. Biocompatibility Assessment of Novel Bioresorbable Alloys Mg-Zn-Se and Mg-Zn-Cu for Endovascular Applications: In- Vitro Studies

    Science.gov (United States)

    Budiansky, Noah; McGoron, Anthony J.

    2013-01-01

    Previous studies have shown that using biodegradable magnesium alloys such as Mg-Zn and Mg-Zn-Al possess the appropriate mechanical properties and biocompatibility to serve in a multitude of biological applications ranging from endovascular to orthopedic and fixation devices. The objective of this study was to evaluate the biocompatibility of novel as-cast magnesium alloys Mg-1Zn-1Cu wt.% and Mg-1Zn-1Se wt.% as potential implantable biomedical materials, and compare their biologically effective properties to a binary Mg-Zn alloy. The cytotoxicity of these experimental alloys was evaluated using a tetrazolium based- MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay and a lactate dehydrogenase membrane integrity assay (LDH). The MTS assay was performed on extract solutions obtained from a 30-day period of alloy immersion and agitation in simulated body fluid to evaluate the major degradation products eluted from the alloy materials. Human foreskin fibroblast cell growth on the experimental magnesium alloys was evaluated for a 72 hour period, and cell death was quantified by measuring lactate dehydrogenase concentrations. Both Mg-Zn-Se and Mg-Zn-Cu alloys exhibit low cytotoxicity levels which are suitable for biomaterial applications. The Mg-Zn-Cu alloy was found to completely degrade within 72 hours, resulting in lower human foreskin fibroblast cell viability. The Mg-Zn-Se alloy was shown to be less cytotoxic than both the Mg-Zn-Cu and Mg-Zn alloys. PMID:24058329

  12. Biocompatibility Assessment of Novel Bioresorbable Alloys Mg-Zn-Se and Mg-Zn-Cu for Endovascular Applications: In- Vitro Studies.

    Science.gov (United States)

    Persaud-Sharma, Dharam; Budiansky, Noah; McGoron, Anthony J

    2013-01-01

    Previous studies have shown that using biodegradable magnesium alloys such as Mg-Zn and Mg-Zn-Al possess the appropriate mechanical properties and biocompatibility to serve in a multitude of biological applications ranging from endovascular to orthopedic and fixation devices. The objective of this study was to evaluate the biocompatibility of novel as-cast magnesium alloys Mg-1Zn-1Cu wt.% and Mg-1Zn-1Se wt.% as potential implantable biomedical materials, and compare their biologically effective properties to a binary Mg-Zn alloy. The cytotoxicity of these experimental alloys was evaluated using a tetrazolium based- MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay and a lactate dehydrogenase membrane integrity assay (LDH). The MTS assay was performed on extract solutions obtained from a 30-day period of alloy immersion and agitation in simulated body fluid to evaluate the major degradation products eluted from the alloy materials. Human foreskin fibroblast cell growth on the experimental magnesium alloys was evaluated for a 72 hour period, and cell death was quantified by measuring lactate dehydrogenase concentrations. Both Mg-Zn-Se and Mg-Zn-Cu alloys exhibit low cytotoxicity levels which are suitable for biomaterial applications. The Mg-Zn-Cu alloy was found to completely degrade within 72 hours, resulting in lower human foreskin fibroblast cell viability. The Mg-Zn-Se alloy was shown to be less cytotoxic than both the Mg-Zn-Cu and Mg-Zn alloys.

  13. Electrochemical and theoretical complexation studies for Zn and Cu with individual polyphenols

    Energy Technology Data Exchange (ETDEWEB)

    Esparza, I. [Departamento de Quimica y Edafologia, Universidad de Navarra, c/ Irunlarrea s/n, 31080 Pamplona, Navarra (Spain); Salinas, I. [Departamento de Quimica y Edafologia, Universidad de Navarra, c/ Irunlarrea s/n, 31080 Pamplona, Navarra (Spain); Santamaria, C. [Departamento de Quimica y Edafologia, Universidad de Navarra, c/ Irunlarrea s/n, 31080 Pamplona, Navarra (Spain); Garcia-Mina, J.M. [INABONOS, Poligono Arazuri, 31160 Orcoyen, Navarra (Spain); Fernandez, J.M. [Departamento de Quimica y Edafologia, Universidad de Navarra, c/ Irunlarrea s/n, 31080 Pamplona, Navarra (Spain)]. E-mail: jmfdez@unav.es

    2005-07-06

    Zn and Cu interactions with three selected flavonoids (catechin, quercetin and rutin) have been electrochemically monitored. It has been shown that catechin takes one atom of metal per molecule; quercetin takes two atoms, and rutin is able to take up to three atoms. Not all ligands bind metals equally strong, and weakly bonded metals can be distinguished. Zn shows a sluggish kinetics and, at the same time, the highest conditional formation constants. The method could be applied to a real sample. Theoretical models are proposed for the most favourable compounds.

  14. Cu2ZnSnS4 thin films solar cells: material and device characterization

    OpenAIRE

    2014-01-01

    Cu2ZnSnS4 (CZTS) quaternary compound has attracted much attention in the last years as new abundant, low cost and non-toxic material, with desirable properties for thin film photovoltaic (PV) applications. In this work, CZTS thin films were grown using two different processes, based on vacuum deposition of precursors, followed by a heat treatment in sulphur atmosphere. The precursors were deposited using two different approaches: (i) electron-beam evaporation of multiple stacks made of ZnS, S...

  15. Phase decomposition of cast alloy ZnAl11Cu3

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Y.H. [Hong Kong Polytechnic Univ. (China). Dept. of Mfg. Engineering; Inst. de Investigaciones en Materiales-UNAM, Mexico (Mexico); Yeung, C.F.; Lee, W.B. [Hong Kong Polytechnic Univ. (China). Dept. of Mfg. Engineering

    2001-12-01

    Microstructure and phase transformation of a cast Zn-Al-based alloy (ZnAl11Cu3) are studied during ageing using X-ray diffraction and back-scattered scanning electron microscopy techniques. Decomposition of a zinc-rich {eta}'{sub s} phase is observed to take place in the way of continuous precipitation. A four-phase transformation, {alpha} + {epsilon} {yields} T'+ {eta}, occurs during prolonged ageing. It is found that the phases involved in the phase transformation can be distinctly identified by using different atomic contrasts in the back-scattered scanning electron image of precipitates. (orig.)

  16. CdS quantum dots sensitized Cu doped ZnO nanostructured thin films for solar cell applications

    Science.gov (United States)

    Poornima, K.; Gopala Krishnan, K.; Lalitha, B.; Raja, M.

    2015-07-01

    ZnO nanorods and Cu doped ZnO nanorods thin films have been prepared by simple hydrothermal method. CdS quantum dots are sensitized with Cu doped ZnO nanorod thin films using successive ionic layer adsorption and reaction (SILAR) method. The X-ray diffraction study reveals that ZnO nanorods, and CdS quantum dot sensitized Cu doped ZnO nanorods exhibit hexagonal structure. The scanning electron microscope image shows the presence of ZnO nanorods. The average diameter and length of the aligned nanorod is 300 nm and 1.5 μm respectively. The absorption spectra shows that the absorption edge of CdS quantum dot sensitized ZnO nanorod thin film is shifted toward longer wavelength region when compared to the absorption edge of ZnO nanorods film. The conversion efficiency of the CdS quantum dot sensitized Cu doped ZnO nanorod thin film solar cell is 1.5%.

  17. Structural and optical characterization of 1 µm of ternary alloy ZnCuSe thin films

    Science.gov (United States)

    Shaaban, E. R.; Hassan, H. Shokry; Aly, S. A.; Elshaikh, H. A.; Mahasen, M. M.

    2016-08-01

    Different compositions of Cu-doped ZnSe in ternary alloy Zn1- x Cu x Se thin films (with x = 0, 0.025, 0.05, 0.075 and 0.10) were evaporated (thickness 1 µm) onto glass substrate using electron beam evaporation method. The X-ray diffraction analysis for both powder and films indicated their polycrystalline nature with zinc blende (cubic) structure. The crystallite size was found to increase, while the lattice microstrain was decreased with increasing Cu dopant. The optical characterization of films was carried out using the transmittance spectra, where the refractive indices have been evaluated in transparent and medium transmittance regions using the envelope method, suggested by Swanepoel. The refractive index has been found to increase with increasing Cu content. The dispersion of refractive index has been analyzed in terms of the Wemple-DiDomenico single-oscillator model. The oscillator parameters, the single-oscillator energy E o, the dispersion energy E d and the static refractive index n 0, were estimated. The optical band gap was determined in strong absorption region of transmittance spectra and was found to increase from 2.702 to 2.821 eV with increasing the Cu content. This increase in the band gap was well explained by the Burstein-Moss effect.

  18. Synthesis of ZnO Nanowires via Hotwire Thermal Evaporation of Brass (CuZn Assisted by Vapor Phase Transport of Methanol

    Directory of Open Access Journals (Sweden)

    Tamil Many K. Thandavan

    2014-01-01

    Full Text Available Zinc oxide (ZnO nanowires (NWs were synthesized using vapor phase transport (VPT and thermal evaporation of Zn from CuZn. Time dependence of ZnO NWs growth was investigated for 5, 10, 15, 20, 25, and 30 minutes. Significant changes were observed from the field electron scanning electron microscopy (FESEM images as well as from the X-ray diffraction (XRD profile. The photoluminescence (PL profile was attributed to the contribution of oxygen vacancy, zinc interstitials, and hydrogen defects in the ZnO NWs. Raman scattering results show a significant peak at 143 cm−1 and possible functionalization on the wall of ZnO NWs. Growth of ZnO NWs in (0002 with an estimated distance between adjacent lattice planes 0.26 nm was determined from transmission electron microscopy (TEM analysis.

  19. KCN Chemical Etch for Interface Engineering in Cu2ZnSnSe4 Solar Cells

    OpenAIRE

    Buffiere, Marie; Brammertz, Guy; Sahayaraj, Sylvester; Batuk, Maria; KHELIFI, SAMIRA; Mangin, Denis; El Mel, Abdel-Aziz; Arzel, Ludovic; Hadermann, Joke; Meuris, Marc; Poortmans, Jef

    2015-01-01

    The removal of secondary phases from the surface of the kesterite crystals is one of the major challenges to improve the performances of Cu2ZnSn(S,Se)(4) (CZTSSe) thin film solar cells. In this Contribution, the KCN/KOH Chemical etching approach, originally developed for the removal of CuxSe phases in Cu(In,Ga)(S,Se)(2) thin films) is applied to CZTSe absorbers exhibiting various chemical compositions. Two distinct electrical behaviors were observed on CZTSe/CdS solar cells after treatment: (...

  20. New processing approaches for Cu2ZnSnSe4-based solar cells

    OpenAIRE

    López Mariño, Simón

    2016-01-01

    The present thesis focuses on the promising semiconductor material kesterite, Cu2ZnSn(S,Se)4, known as CZTS(e), which is used in the second generation of solar cells, generally known as thin film photovoltaics (PV). This material relies on earth-abundant, low-cost and low toxic elements which certainly attract the interest of both research community and industry. Kesterite could replace its well known and already commercialised thin film counterpart, CuIn(1-x)Gax(SySe1-y)2 (CIGS), since it ha...

  1. Transient behavior of Cu/ZnO-based methanol synthesis catalysts

    DEFF Research Database (Denmark)

    Vesborg, Peter Christian Kjærgaard; Chorkendorff, Ib; Knudsen, Ida;

    2009-01-01

    Time-resolved measurements of the methanol synthesis reaction over a Cu/ZnO-based catalyst reveal a transient methanol production that depends on the pretreatment gas. Specifically, the methanol production initially peaks after a pretreatment with an intermediate mixture of H2 and CO (20–80% H2...... for a gas mixture of H2:CO = 1:1. The gas-dependent morphology of the Cu nanoparticles provides a consistent explanation of the observed coupling between the transient methanol production and pretreatment conditions within the framework of the dynamic microkinetic model by Ovesen et al. [J. Catal. 168 (1997...

  2. Detection of Cu{sub 2}Zn{sub 5}SnSe{sub 8} and Cu{sub 2}Zn{sub 6}SnSe{sub 9} phases in co-evaporated Cu{sub 2}ZnSnSe{sub 4} thin-films

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, Torsten, E-mail: schwarz@mpie.de; Cojocaru-Mirédin, Oana; Raabe, Dierk; Choi, Pyuck-Pa, E-mail: choi@mpie.de [Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Straße 1, 40237 Düsseldorf (Germany); Marques, Miguel A. L.; Botti, Silvana [Institut Lumière Matière (UMR5306) and ETSF, Univerité Lyon 1-CRNS, Université de Lyon, F-69622 Villeurbanne (France); Mousel, Marina; Redinger, Alex; Siebentritt, Susanne [Laboratory for Photovoltaics, University of Luxembourg, 41, rue du Brill, L-4422 Belvaux (Luxembourg)

    2015-10-26

    Cu{sub 2}ZnSnSe{sub 4} thin-films for photovoltaic applications are investigated using combined atom probe tomography and ab initio density functional theory. The atom probe studies reveal nano-sized grains of Cu{sub 2}Zn{sub 5}SnSe{sub 8} and Cu{sub 2}Zn{sub 6}SnSe{sub 9} composition, which cannot be assigned to any known phase reported in the literature. Both phases are considered to be metastable, as density functional theory calculations yield positive energy differences with respect to the decomposition into Cu{sub 2}ZnSnSe{sub 4} and ZnSe. Among the conceivable crystal structures for both phases, a distorted zinc-blende structure shows the lowest energy, which is a few tens of meV below the energy of a wurtzite structure. A band gap of 1.1 eV is calculated for both the Cu{sub 2}Zn{sub 5}SnSe{sub 8} and Cu{sub 2}Zn{sub 6}SnSe{sub 9} phases. Possible effects of these phases on solar cell performance are discussed.

  3. Construction of Plant Expression Vector of Cu/Zn-SOD Gene and Its Expression in Tobacco%Cu/Zn-SOD基因植物表达载体的构建及其在烟草中的表达

    Institute of Scientific and Technical Information of China (English)

    姚冉; 李轶女; 张志芳; 沈桂芳; 潘沈元

    2012-01-01

    为研究Cu/Zn-SOD基因在提高转基因植物抗逆性方面的作用,从一株地热芽孢杆菌(Geobacillus)中克隆得到Cu/Zn-SOD基因,以pZP211质粒为表达载体,构建了植物表达载体pZP211-Cu/ZnSOD,并通过农杆菌介导对烟草进行遗传转化.经PCR检测证明已获得转Cu/Zn-SOD基因的烟草.进而测定转基因烟草的SOD活力,结果表明Cu/Zn-SOD基因在烟草中高效表达.对转基因烟草进行耐盐性检测,证明Cu/Zn-SOD基因确实能够提高烟草对盐胁迫的耐受性.

  4. The influences of dissolved organic matter and surfactant on the desorption of Cu and Zn from road-deposited sediment.

    Science.gov (United States)

    Zhang, Jin; Hua, Pei; Krebs, Peter

    2016-05-01

    This study showcases the desorption behaviours of copper (Cu) and zinc (Zn) in road-deposited sediment (RDS). Batch tests were conducted to investigate the influences of rainwater, major wastewater constituents of dissolved organic matter (DOM) and surfactant on the metals leaching from RDS. Results show that the rainwater solutions considerably enhanced the total amounts of Cu (319 ± 46% of the total leaching amount by blank solutions) and Zn (617 ± 130%) released from RDS compared with blank solutions. DOM enhanced the leaching of Cu from RDS at a neutral pH. By contrast, DOM had an adverse effect on the mobilization of Zn. In the absence of DOM, a higher concentration of sodium dodecyl sulfonate (SDS) slightly increased the release of Cu from RDS than a lower concentration of SDS. However, the existence of SDS suppressed the release of Zn from RDS.

  5. Room Temperature Ferromagnetism and Structure of Zn_(1-x)Cu_xO Films Synthesized by Radio Frequency Magnetron Sputtering

    Institute of Scientific and Technical Information of China (English)

    CHEN Xuemei; ZHUGE Lanjian; WU Xuemei; WU Zhaofeng

    2009-01-01

    Zn_(1-x)Cu_xO thin films were synthesized by the radio frequency (RF) magnetron sputtering technique using a ZnO target containing different pieces of small Cu-chips.X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to analyze the crystalline and microstructure of the film,and X-ray photoelectron spectroscopy (XPS) was used to establish the bonding characteristics and oxidation states of copper inside the ZnO host.Room temperature (RT) ferromagnetism was observed in the Zn_(1-x)Cu_xO films by a Quantum Design superconducting quantum interference device (SQUID) and the saturation magnetic moment of the films was found to decrease with the increase in Cu content.

  6. Influence of synthesis conditions on particle morphology of nanosized Cu/ZnO powder by polyol method

    Indian Academy of Sciences (India)

    Tuba Gürkaynak Altinçekiç; Ismail Boz

    2008-08-01

    Cu/ZnO in nanosizes have been synthesized using ethylene glycol at various conditions. The effects of reaction temperature, extent of reduction, various precursors such as CuX$_{2}.n$H2O, ZnX$_{2}.n$H2O (X = Cl–, NO$^{–}_{3}$, CH3CO$^{–}_{2}$), the addition of water and the removal of volatile compounds including water were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and dynamic light scattering (DLS). Cu/ZnO powders with an average diameter of as low as 50 nm was obtained with a very low polydispersity in the absence of a protective polymer. Ethylene glycol oxidation products were also identified by Fourier transform infrared (FTIR) spectroscopy. The morphology of Cu/ZnO powders and the yield of powders are found to be strongly dependent on the synthesis conditions.

  7. Speciation of ZnO and CuO nanoparticles exposed to culture medium and lymphocyte cells

    Data.gov (United States)

    U.S. Environmental Protection Agency — Spectral fits and linear combination data for ZnO and CuO nanoparticles exposure during toxicity testing. This dataset is associated with the following publication:...

  8. Hydrogenolysis of Glycerol to Propylene Glycol on Nanosized Cu-Zn-Al Catalysts Prepared Using Microwave Process.

    Science.gov (United States)

    Kim, Dong Won; Ha, Sang Ho; Moon, Myung Jun; Lim, Kwon Taek; Ryu, Young Bok; Lee, Sun Do; Lee, Man Sig; Hong, Seong-Soo

    2015-01-01

    Cu-Zn-Al catalysts were prepared using microwave-assisted process and co-precipitation methods. The prepared catalysts were characterized by XRD, BET, XPS and TPD of ammonia and their catalytic activity for the hydrogenolysis of glycerol to propylene glycol was also examined. The XRD patterns of Cu/Zn/Al mixed catalysts show CuO and ZnO crystalline phase regardless of preparation method. The highest glycerol hydrogenolysis conversion is obtained with the catalyst having a Cu/Zn/Al ratio of 2:2:1. Hydrogen pre-reduction of catalysts significantly enhanced both glycerol conversions and selectivity to propylene glycol. The glycerol conversion increased with an increase of reaction temperature. However, the selectivity to propylene glycol increased with an increase of temperature, and then declined to 30.5% at 523 K.

  9. Effects of Phosphate Adsorption on Adsorption Desorption and Availability of Cu and Zn Ions in Ultisols and Alfisols

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Surface charge, secondary adsorption-desorption and form distribution of Cu2+ and Zn2+ in Ultisols and Alfisols having adsorbed phosphate were studied by potentiometric titration, adsorption equilibrium and sequential extraction method, respectively. The soil surface negative charges increased whereas the amount of positive charges decreased with increase of P adsorbed. The soil secondary adsorption capacity for Cu2+and Zn2+ was positively significantly correlated with the amount of P adsorbed by the soils, which could be described by the Langmuir equation. The amounts of Cu2+ and Zn2+ desorption from soils were decreased after P adsorption by the soils and the relationship between them was linear. After the soils adsorbed P,form distribution of Cu2+ and Zn2+ in soils changed remarkably.

  10. Mobility and speciation of Cd,Cu,and Zn in two acidic soils affected by simulated acid rain

    Institute of Scientific and Technical Information of China (English)

    GUO Zhao-hui; LIAO Bo-han; HUANG Chang-yong

    2005-01-01

    Through a batch experiment, the mobility and speciation of heavy metals(Cd, Cu, Zn) in two acidic forest soils from Hunan Province were studied. The results showed that the release and potential active speciation of Cd, Cu, and Zn in the tested contaminated red soil(CRS) and yellow red soil(CYRS) increased significantly with pH decreasing and ion concentrations increasing of simulated acid rain, and these effects were mainly decided by the pH value of simulated acid rain. Cd had the highest potential risk on the environment compared with Cu and Zn. Cd existed mainly in exchangeable form in residual CRS and CYRS, Cu in organically bound and Mn-oxide occluded forms, and Zn in mineral forms due to the high background values.

  11. TPR and TPD studies of effects of Cu and Ca promotion on Fe-Zn-based Fischer-Tropsch catalysts

    Indian Academy of Sciences (India)

    Olusola O James; Biswajit Chowdhury; Sudip Maity

    2013-05-01

    Temperature-programmed reduction (TPR) and temperature-programmed desorption (TPD) were used to study the effects of Cu and Ca promotion on Fe-Zn-based Fischer-Tropsch catalysts. The reduction temperature for Fe2O3 → Fe3O4 was unaffected by Ca addition but decreased when promoted with Cu. Fe-Zn promoted with Cu and Ca showed even much lower reduction temperature for Fe2O3→Fe3O4. Ca promotion enhances carburization and increases surface acidity and basicity of the Fe-Zn oxide precursor. While Cu inhibits carburization and decreases the surface acidity and basicity of the Fe-Zn oxide precursor. The implications of these effects on the application of catalysts for FT are discussed.

  12. Effect of Cu concentration on the formation of Cu{sub 1−x} Zn{sub x} shape memory alloy thin films

    Energy Technology Data Exchange (ETDEWEB)

    Karahan, İsmail Hakkı [Department of Physics, Mustafa Kemal University, Hatay 31000 (Turkey); Özdemir, Rasim, E-mail: ihkarahan@gmail.com [Department of Physics, Mustafa Kemal University, Hatay 31000 (Turkey); Kilis Vocational High School, Kilis 7 Aralık University, 79000 Kilis (Turkey)

    2014-11-01

    Highlights: • 3 different composition of Cu–Zn deposits successfully deposited from the non-cyanide sulphate electrolyte. • The homogeneous metal films and Cu–Zn alloys were electrodeposited on Al substrate. • The effect of Cu content was strongly effected structural and the electrical resistivity of Cu–Zn alloys. • The average crystallite size of the samples varied from 66 to 100 nm and decreased when Cu content in the electrolyte. • Microstrain has been decreased with increasing crystallite size. • Cyclic voltammetry of the electrolyte explained the characters of the baths. - Abstract: The Cu{sub x}Zn1−x (x = 0.06, 0.08, 0.1) deposits were fabricated by a electrodeposition method. The structural and electrical properties of the films were investigated by cyclic voltammetry (CV), X-ray diffraction (XRD), Scanning electron micrograph (SEM), and DC resistivity measurements. Phase identification of the samples was studied by the XRD patterns. XRD patterns shows the characteristics XRD peaks corresponding to the, β, and γ phases. The grain sizes of the samples were decreased whereas microstrain increased with the increase in Cu{sup 2+} substitution. The SEM study reveals the fine particle nature of the samples with increasing Cu content. DC resistivity indicates the metallic nature of the prepared samples. It has been found that the Cu ions have a critical influence on the resultant structure and resistivity properties of the Cu–Zn samples.

  13. Role of microbial inoculation and chitosan in phytoextraction of Cu, Zn, Pb and Cd by Elsholtzia splendens - a field case

    Energy Technology Data Exchange (ETDEWEB)

    Wang Fayuan [Agricultural College, Henan University of Science and Technology, 70 Tianjin Road, Luoyang, Henan Province 471003 (China) and Institute of Soil Science, Chinese Academy of Sciences, Nanjing, Jiangsu Province 210008 (China)]. E-mail: wfy1975@163.com; Lin Xiangui [Institute of Soil Science, Chinese Academy of Sciences, Nanjing, Jiangsu Province 210008 (China); Yin Rui [Institute of Soil Science, Chinese Academy of Sciences, Nanjing, Jiangsu Province 210008 (China)

    2007-05-15

    A field experiment was carried out to study the effect of microbial inoculation on heavy metal phytoextraction by Elsholtzia splendens and whether chitosan could have a synergistic effect with the microbial inocula. The microbial inocula consisted of a consortium of arbuscular mycorrhizal fungi and two Penicillium fungi. Three treatments were included: the control, inoculation with microbial inocula, and the inoculation combined with chitosan. Microbial inoculation increased plant biomass especially shoot dry weight, enhanced shoot Cu, Zn and Pb concentrations but did not affect Cd, leading to higher shoot Cu, Zn, Pb and Cd uptake. Compared with microbial inoculation alone, chitosan application did not affect plant growth but increased shoot Zn, Pb and Cd concentrations except Cu, which led to higher phytoextraction efficiencies and partitioning to shoots of Zn, Pb and Cd. These results indicated synergistic effects between microbial inocula and chitosan on Zn, Pb and Cd phytoextraction. - Co-application of microbial inocula and chitosan enhanced heavy metal phytoextraction by E. splendens.

  14. Effect of ZnTe/ZnTe:Cu complex back-contact on device characteristics of CdTe solar cells

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    ZnTe/ZnTe:Cu complex layers deposited by vacuum co-evaporation have been in- troduced to CdS/CdTe solar cells. The C-V and I-V curves have been investigated and the effects of un-doped ZnTe layer thickness as well as annealing temperatures on I-V characteristics of CdTe solar cells have been studied. The results show that the “roll over” and “cross over” phenomena of dark and light I-V curves can be eliminated by use of ZnTe/ZnTe:Cu layer and the fill factor for a typical sample has increased to 73%, where there is no high resistance transparent layer. The reasons have been discussed combined with the energy band diagram of CdTe solar cells.

  15. Catalytic Properties of ZSM-5 based Cu-Zn Catalysts Applies to Ethanol Synthesis from Syngas

    Directory of Open Access Journals (Sweden)

    Xu He-Shuang

    2016-01-01

    Full Text Available Cu-Zn catalysts based on ZSM-5 were prepared with impregnation method. Their catalatic behaviors for the synthesis of ethanol from syngas were investigated in a fixed bed. XRD and H2-TPR were adopted to characterize the structure and of the catalysts. In the synthesis procession, such factors as ZSM-5 with varied n(Si/n(Al ratio, reaction temperature and space velocity were inspected carefully. The results showed that: changing the ratio of silica to alumina in the carrier zeolite has a great influence on the conversion of CO.with a n(Si/n(Al ratio of 80, the conversion rate of CO peaked at 25% and the selectivity to ethanol reached 22%. Optimal space velocity for Cu-Zn catalysts was 8400·mL−1·h−1·g−1.

  16. Microstructure and thermal expansion properties of invar-type Cu-Zn-Al shape memory alloys

    Science.gov (United States)

    Wang, J. J.; Omori, T.; Sutou, Y.; Kainuma, R.; Ishida, K.

    2004-10-01

    The effects of grain size, volume fraction of the α (fcc) phase in the β (bcc) matrix, and thermal stability on low thermal expansion (LTE) properties of Cu-Zn-Al shape memory (SM) alloys induced by cold rolling were investigated by dilatometry, optical microscopy, differential scanning calorimetry, and electrical conductivity measurements. The alloys with the larger grains showed a superior two-way memory (TWM) effect, wider LTE temperature intervals with excellent thermal stability under 80°C. The α+β two-phase alloys also exhibited a good combination of cold workability and LTE properties. These results suggest that the Cu-Zn-Al alloys with high electrical conductivity of about 20% International Annealed Copper Standard (%IACS) have high potential as a new class of Invar alloys that can be applied in various fields.

  17. Antimicrobial effects of metal ions (Ag+, Cu2+, Zn2+) in hydroxyapatite.

    Science.gov (United States)

    Kim, T N; Feng, Q L; Kim, J O; Wu, J; Wang, H; Chen, G C; Cui, F Z

    1998-03-01

    The antimicrobial ceramics (AC) based on hydroxyapatite (HA) were made in a wet chemical process with additions of AgNO3, Cu(NO3)2. 3H2O and Zn(NO3)2. 6H2O. The ACs were composed of metal-ion substituted hydroxyapatite and nitrate-apatite, which was identified by X-ray diffraction. The viable count and turbidity measurement was adopted to observe the antimicrobial effects of the various ACs. The aerobic Escherichia coli was used in the study. An obvious antimicrobial effect against E. coli was observed in Ag+ AC. In contrast to Ag+ AC, it was difficult to ascertain any bactericidal effect in the case of Cu2+ and Zn2+ AC. The bactericidal effect of Ag+ was observed using a dialysis tube experiment. This suggests that Ag+ dissolved out and reacted with E. coli, thus inhibiting its growth.

  18. Ultra-thin Cu2ZnSnS4 solar cell by pulsed laser deposition

    DEFF Research Database (Denmark)

    Cazzaniga, Andrea Carlo; Crovetto, Andrea; Yan, Chang

    2017-01-01

    We report on the fabrication of a 5.2% efficiency Cu2ZnSnS4 (CZTS) solar cell made by pulsed laser deposition (PLD) featuring an ultra-thin absorber layer (less than 450 nm). Solutions to the issues of reproducibility and micro-particulate ejection often encountered with PLD are proposed. At the ......We report on the fabrication of a 5.2% efficiency Cu2ZnSnS4 (CZTS) solar cell made by pulsed laser deposition (PLD) featuring an ultra-thin absorber layer (less than 450 nm). Solutions to the issues of reproducibility and micro-particulate ejection often encountered with PLD are proposed....... At the optimal laser fluence, amorphous CZTS precursors with optimal stoichiometry for solar cells are deposited from a single target. Such precursors do not result in detectable segregation of secondary phases after the subsequent annealing step. In the analysis of the solar cell device, we focus on the effects...

  19. Microstructure and Shape Memory Effect of Cu-26.1Zn-4.8Al Alloy

    Institute of Scientific and Technical Information of China (English)

    CHENG Xiaomin; HUANG Feng; LI Na; WU Xingwen

    2008-01-01

    The influence of processing parameters on the microstructure and shape memory effect of Cu-26.1Zn-4.8Al alloy was investigated. The treated specimens were characterized by metallography, X-ray diffraction (XRD) and transmission electron microscopy (TEM) to explain the mechanism of shape memory effect in Cu-26.1Zn-4.8Al alloy. The results reveal that the shape memory effect is markedly increased by appropriate quenching and ageing process. XRD shows that γ-phase precipitates from martensite when aged at higher temperature and γ precipitates impair the shape memory effect. TEM analysis indicate that the substructure of plate-like martensite consists of twins and stacking faults.

  20. Structure and function of Cu(I)- and Zn(II)-ATPases

    DEFF Research Database (Denmark)

    Sitsel, Oleg; Grønberg, Christina; Autzen, Henriette

    2015-01-01

    membranes at the expense of ATP. Recent biochemical studies and crystal structures have significantly improved our understanding of the transport mechanisms of these proteins, but many details about their structure and function remain elusive. Here we compare the Cu(I)- and Zn(II)-ATPases, scrutinizing......Copper and zinc are micronutrients essential for the function of many enzymes while also being toxic at elevated concentrations. Cu(I)- and Zn(II)-transporting P-type ATPases of subclass 1B are of key importance for the homeostasis of these transition metals, allowing ion transport across cellular...... the molecular differences that allow transport of these two distinct metal types, and discuss possible future directions of research in the field....

  1. Methanol Steam Reforming Reactions on CuZn(Zr)AlO Catalyst

    Institute of Scientific and Technical Information of China (English)

    Yongfeng Li; Xinfa Dong; Weiming Lin

    2004-01-01

    The catalytic performances of methanol steam reforming reactions on CuZn(Zr)AlO catalysts were studied. When the ZrO2 promoter was added to a CuZnAlO catalyst, its methanol conversion,H2 production and H2 selectivity improved greatly. By using the #COPZr-2 catalyst as an example,which exhibited the best catalytic performance, the optimized reaction conditions were established to be:250 ℃, 0.1 MPa, H2O/MeOH=1.3, WHSV=3.56 h-1, and without carrier gas. A 150 h stability test of the #COPZr-2 catalyst showed that the catalyst had good stability, as the methanol conversion and H2 production could be kept at 88% and 83% respectively. Moreover, outlet H2 and CO contents were >63%and 0.20%-0.31%, respectively.

  2. A novel electrochemical alkylation of aniline with methanol over Zn/Cu salts modified kaolin

    Energy Technology Data Exchange (ETDEWEB)

    Ma Hongzhu [Institute of Energy-Chemistry, College of Chemistry and Materials Science, Shaanxi Normal University, Xi' An 710062 (China); Wang Bo [Institute of Energy-Chemistry, College of Chemistry and Materials Science, Shaanxi Normal University, Xi' An 710062 (China)], E-mail: wangbo@snnu.edu.cn; Zhao, Jun [Institute of Energy-Chemistry, College of Chemistry and Materials Science, Shaanxi Normal University, Xi' An 710062 (China)

    2008-04-01

    A novel liquid phase alkylation of aniline with methanol over Zn/Cu salts modified kaolin assisted with a pair of porous carbon electrode in slurry-bed reactor under constant current intensity, room temperature and atmospheric pressure was reported. The Zn/Cu salts modified kaolin catalysts were synthesized and characterized by infrared spectrometer (IR), powder X-ray diffraction (XRD) and scanning electron microscopy (SEM), which showed that the transition metals were completely supported on kaolin's structure and formed a pored one. The effect parameters, such as initial pH, electrolysis time, metal ratio with kaolin and salts composition in this electrochemical catalytic system, were studied. The procedure was inspected by ultraviolet-visible spectrum (UV-vis), and the product distribution was detected by gas chromatography/mass spectrometry (GC/MS). In addition, a possible reaction mechanism was also proposed.

  3. Microstructure and phase stress partition of Mo fiber reinforced CuZnAl composite

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Feng [State Key Laboratory of Heavy Oil Processing, China University of Petroleum-Beijing, Beijing 102249 (China); Department of Materials Science and Engineering, China University of Petroleum-Beijing, Beijing 102249 (China); Ni, Dingrui [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Hao, Shijie [State Key Laboratory of Heavy Oil Processing, China University of Petroleum-Beijing, Beijing 102249 (China); Department of Materials Science and Engineering, China University of Petroleum-Beijing, Beijing 102249 (China); Li, Sirui [Department of Materials Science and Engineering, China University of Petroleum-Beijing, Beijing 102249 (China); Ma, Zongyi [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Liu, Yinong [School of Mechanical and Chemical Engineering, The University of Western Australia, Crawley, WA 6009 (Australia); Feng, Chun [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); Cui, Lishan, E-mail: andor_20@sina.com [State Key Laboratory of Heavy Oil Processing, China University of Petroleum-Beijing, Beijing 102249 (China); Department of Materials Science and Engineering, China University of Petroleum-Beijing, Beijing 102249 (China)

    2015-03-25

    A Mo fiber reinforced CuZnAl composite was prepared by means of friction stir processing and wire drawing. Reinforcing effect of the Mo fiber and phase stress partition in the composite were investigated by means of in-situ synchrotron X-ray diffraction. The maximum elastic strain of the Mo fiber achieved was 1.8%, implying a component stress of 550 MPa on the fibers. The Mo fibers, with a volume fraction of 10%, carried 80% of stress fraction during tensile deformation. The change of modulus caused by stress-induced martensitic transformation strain resulted in redistribution of the phase stress partition between Mo fibers and CuZnAl matrix.

  4. A Study of Occurrences of Ag in Pb-Zn-Cu Ore Deposits in China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A systematic study of occurrences of silver in 156 Pb-Zn-Cu ore deposits indicates that silver mainly occurs in nonferrous metal ore deposits in forms of association and paragenesis. It occurs mainly as independent minerals in nature and occasionally as ion adsorption, isomorphous or amorphous silver minerals. Nearly 190 silver minerals have been discovered in China. Their shapes, constituents, textures, grain sizes, embedded types, distribution patterns, mineral assemblages and metallogenic series suggest that these characteristics are closely related to geneses of deposits and dependent of ore-forming conditions. Pb, Zn and Cu sulphides are the main carrier minerals of silver. The partition of silver in ore is constrained by the mineralization intensity, grain size and embedded form of silver minerals and mineral assemblages.

  5. Ab initio study of heterojunction discontinuities in the ZnO/Cu2O system

    Science.gov (United States)

    Zemzemi, M.; Alaya, S.; Ben Ayadi, Z.

    2014-06-01

    Solar cells based on transparent conductive oxides such as ZnO/Cu2O constitute a very advanced way to build high-performance cells. In this work, we are interested in the characterization of the interface through nanoscale modeling based on ab initio approaches (density functional theory, local density approximation, and pseudopotential). This work aims to build a supercell containing a heterojunction ZnO/Cu2O and study the structural properties and the discontinuity of the valence band (band offset) from a semiconducting to another phase. We build a zinc oxide in the wurtzite structure along [0001] on which we place the copper oxide in the hexagonal (CdI2-type) structure. We choose the method of Van de Walle and Martin to calculate the energy offset. This approach fits well the density functional theory. Our calculation of the band offset gives a value that corresponds to other experimental and theoretical values.

  6. Enhanced photocurrent ZnO/CdS/CuInSe/sub 2/ solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Potter, R.R.

    1986-02-01

    The short-wavelength spectral response of a thin film CuInSe/sub 2/ device is improved by a thin (less than 500 A) undoped CdS layer and a 1 micron ZnO conducting window layer. The ZnO acts as an antireflection coating and permits photons of wavelength above 360 nm to be absorbed in the CuInSe/sub 2/. A 25-percent photocurrent enhancement is measured for comparable devices. Total area efficiencies over 9 percent are achieved under AM 1.5 illumination. Current-voltage, capacitance-voltage, and spectral response data are discussed. The data indicate that device properties are similar to devices with (In)CdS window layers. A reverse bias breakdown with long time constants is observed. Deep states in the thin CdS layer may be responsible.

  7. Enhanced photocurrent ZnO/CdS/CuInSe/sub 2/ solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Potter, R.R.

    1986-01-15

    The short-wavelength spectral response of a thin film CuInSe/sub 2/ device is improved by a thin (<500 A) undoped CdS layer and a 1 ..mu..m ZnO conducting window layer. The ZnO acts as an antireflection coating and permits photons of wavelength above 360 nm to be absorbed in the CuInSe/sub 2/. A 25% photocurrent enhancement is measured for comparable devices. Total area efficiencies over 9% are achieved under AM 1.5 illumination. Current-voltage, capacitance-voltage and spectral response data are discussed and indicate that device properties are similar to devices with (In) CdS window layers. A reverse bias breakdown with long time constants is observed. Deep states in the thin CdS layer may be responsible.

  8. Zn and Cu Isotopes as Tracers of Anthropogenic Contamination in a Sediment Core from an Urban Lake

    Science.gov (United States)

    Thapalia, Anita; Borrok, David M.; Van Metre, Peter C.; Musgrove, MaryLynn; Landa, Edward R.

    2010-01-01

    In this work, we use stable Zn and Cu isotopes to identify the sources and timing of the deposition of these metals in a sediment core from Lake Ballinger near Seattle, Washington, USA. The base of the Lake Ballinger core predates settlement in the region, while the upper sections record the effects of atmospheric emissions from a nearby smelter and rapid urbanization of the watershed. δ66Zn and δ65Cu varied by 0.50%o and 0.29%o, respectively, over the 500 year core record. Isotopic changes were correlated with the presmelter period (~1450 to 1900 with δ66Zn = +0.39%o ± 0.09%o and δ65Cu = +0.77%o ± 0.06%o), period of smelter operation (1900 to 1985 with δ66Zn = +0.14 ± 0.06%o and δ65Cu = +0.94 ± 0.10%o), and postsmelting/stable urban land use period (post 1985 with δ66Zn = 0.00 ± 0.10%o and δ65Cu = +0.82%o ± 0.12%o). Rapid early urbanization during the post World War II era increased metal loading to the lake but did not significantly alter the δ66Zn and δ65Cu, suggesting that increased metal loads during this time were derived mainly from mobilization of historically contaminated soils. Urban sources of Cu and Zn were dominant since the smelter closed in the 1980s, and the δ66Zn measured in tire samples suggests tire wear is a likely source of Zn.

  9. Research on Solidification Behavior of Ag-Cu-Zn Alloys%Ag-Cu-Zn合金凝固行为的研究

    Institute of Scientific and Technical Information of China (English)

    陈永泰; 谢明; 杨有才; 张吉明; 刘满门; 王松; 王塞北; 胡洁琼; 李爱坤

    2015-01-01

    对Ag-6Cu-xZn(x=0,1,2)合金铸态显微组织、物相及凝固行为进行了研究,结果表明,Zn对Ag-Cu合金的二次枝晶间距有细化作用;Ag-6Cu-xZn合金主要由α相(富Ag固溶体相)和少量的β相(富Cu和Zn固溶体相)组成,β相弥散分布于二次枝晶间;Zn的添加降低了合金及第二相的熔化温度,且 Zn 含量越高,合金熔化温度降低趋势越大,其凝固特征是一个典型的固溶体合金的非平衡凝固过程。%The as-cast microstructure, chemical phase and solidification behavior of Ag-6Cu-xZn (x=0, 1, 2) alloys were investigated. The results indicate that, the Zn in Ag-Cu alloy could refine the secondary dendrite arm spacing, but its refining effect is limited. The Ag-Cu-Zn alloy is mainly composed ofα phase (silver-rich phase) and littleβ phase ((copper, zinc)-rich phase).βphases are dispersively distributed in secondary dendrite, they will help to improve the abrasion resistance properties of materials. Adding Zn can reduce the melting temperature of the alloy and the second phase, the higher content of Zn, the greater tendency to reduce the melting temperature of the alloy, the solidification feature of Ag-Cu-Zn alloy is a typical of non-equilibrium solidification of Solid Solution.

  10. Doctor-bladed Cu2ZnSnS4 light absorption layer for low-cost solar cell application

    Institute of Scientific and Technical Information of China (English)

    Chen Qin-Miao; Li Zhen-Qing; Ni Yi; Cheng Shu-Yi; Dou Xiao--Ming

    2012-01-01

    The doctor-blade method is investigated for the preparation of Cu2ZnSnS4 films for low-cost solar cell application.Cu2ZnSnS4 precursor powder,the main raw material for the doctor-blade paste,is synthesized by a simple ball-milling process.The doctor-bladed Cu2ZnSnS4 films are annealed in N2 ambient under various conditions and characterized by X-ray diffraction,ultravio1lent/vis spectrophotometry,scanning electron microscopy,and current-voltage (J-V)meansurement. Our experimental results indicate that (i) the X-ray diffraction peaks of the Cu2ZnSnS4 precursor powder each show a red shift of about 0.4°; (ii) the high-temperature annealing process can effectively improve the crystallinity of the doctor-bladed Cu2ZnSnS4,whereas an overlong annealing introduces defects; (iii) the band gap value of the doctor-bladed Cu2ZnSnS4 is around 1.41 eV; (iv) the short-circuit current density,the open-circuit voltage,the fill factor,and the efficiency of the best Cu2ZnSnS4 solar cell obtained with the superstrate structure of fluorine-doped tin oxide glass/TiO2/In2S3/Cu2ZnSnS4/Mo are 7.82 mA/cm2,240 mV,0.29,and 0.55%,respectively.

  11. Effect of tellurium on machinability and mechanical property of CuAlMnZn shape memory alloy

    Energy Technology Data Exchange (ETDEWEB)

    Liu Na [School of Materials Science and Engineering, Central South University, Changsha, 410083 (China); Li Zhou, E-mail: lizhou6931@csu.edu.cn [School of Materials Science and Engineering, Central South University, Changsha, 410083 (China); Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Changsha, 410083 (China); Xu Genying; Feng Ze; Gong Shu; Zhu Lilong; Liang Shuquan [School of Materials Science and Engineering, Central South University, Changsha, 410083 (China)

    2011-10-15

    Highlights: {yields} A novel free-machining Cu-7.5Al-9.7Mn-3.4Zn-0.3Te (wt.%) shape memory alloy has been developed. {yields} The size of dispersed particles with richer Te is 2-5 {mu}m. {yields} The CuAlMnZnTe alloy has good machinability which approached that of BZn15-24-1.5 due to the addition of Te. {yields} Its shape memory property keeps the same as that of CuAlMnZn alloy with free Te. {yields} The CuAlMnZn shape memory alloy with and without Te both have good ductile as annealed at 700 deg. C for 15 min. - Abstract: The microstructure transition, shape memory effect, machinability and mechanical property of the CuAlMnZn alloy with and without Te have been studied using X-ray diffraction analysis, chips observation and scanning electron microscopy (SEM), tensile strength test and differential scanning calorimeter (DSC), and semi-quantitative shape memory effect (SME) test. The particles with richer Te dispersedly distributed in grain interior and boundary with size of 2-5 {mu}m. After the addition of Te, the CuAlMnZnTe alloy machinability has been effectively increased to approach that of BZn15-24-1.5 and its shape memory property remains the same as the one of CuAlMnZn alloy. The CuAlMnZn shape memory alloys with and without Te both have good ductility as annealed at 700 deg. C for 15 min.

  12. A density functional study on properties of a Cu3Zn material and CO adsorption onto its surfaces

    Science.gov (United States)

    Tang, Qian-Lin; Duan, Xiao-Xuan; Liu, Bei; Wei, An-Qing; Liu, Sheng-Long; Wang, Qi; Liang, Yan-Ping; Ma, Xiao-Hua

    2016-02-01

    Prior experimental and theoretical efforts have provided strong evidence that the formation of α-brass such as Cu3Zn alloys in Cu/ZnO/Al2O3 CO2/CO hydrogenation catalysts enhances dramatically the catalytic activity toward methanol synthesis. In this work, a density functional theory (DFT) slab model has been adopted to get information concerning the bulk and surface properties of DO23-like Cu3Zn and to explore CO molecular adsorption, which will help pave the way to future rationalization of the impact of surface alloying on Cu/ZnO-based catalysis for CO2 and CO hydrogenations. Our calculations imply that the bulk modulus and cohesive energy of the binary solid solution lie between the corresponding ones for the individual components, but only the former quantity equals its composition weighted average. From the DFT-computed surface energies, the stability of Cu3Zn surfaces was predicted to be reinforced in the sequence (1 1 0) electronic structure evaluation reveals that as far as all the alloy surfaces under scrutiny are concerned, a layer of CO brought a decrease, not an increase, in work function for (1 0 1)Zn and (1 1 0)CuZn, though the electrons always flowed from the substrate to the adsorbate. The finding is not trivial at all since it counters the classical rule that an electronegative species raises the work function of the underlying surface. The bonding of CO to the Cu3Zn systems via C-Cu contacts was identified as being primarily covalent rather than ionic. A simple d-band energy model is able to capture the bonding tendency observed.

  13. Cu2ZnSnS4 solar cells prepared with sulphurized dc-sputtered stacked metallic precursors

    OpenAIRE

    Fernandes, P. A.; Salomé, P M P; Cunha, A. F. da; Schubert, Björn-Arvid

    2010-01-01

    In the present work we report the details of the preparation and characterization results of Cu2ZnSnS4 (CZTS) based solar cells. The CZTS absorber was obtained by sulphurization of dc magnetron sputtered Zn/Sn/Cu precursor layers. The morphology, composition and structure of the absorber layer were studied by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction and Raman scattering. The majority carrier type was identified via a hot point probe analysis....

  14. Preparation and characterization of Cu2ZnSn(S,Se)4 thin films by sulfurization of Cu-Zn-Sn-Se precursor layers

    Science.gov (United States)

    Kim, Yongshin; Choi, In-Hwan

    2017-02-01

    We fabricated Cu2ZnSn(S,Se)4 (CZTSSe) thin films by sulfurization of co-evaporated Cu-Zn-Sn-Se precursor layers under a mixed atmosphere of Ar and H2S. The concentration of H2S in the sulfurization chamber was adjusted to control the replacement of Se by S in CZTSSe thin films. The effect of applying different sulfurization atmospheres was analyzed using X-ray diffraction (XRD), Raman scattering, and secondary electron imaging. XRD patterns and Raman spectra confirmed the formation of polycrystalline CZTSSe thin films. The anion compositions of CZTSSe samples, which depended on the concentration of H2S, were estimated by using the peak heights of A modes in Raman spectra. To further analyze Raman scattering of CZTSSe thin film, we used a diamond anvil cell to apply a high pressure environment of up to 5.13 GPa on the CZTSSe sample. The effect of H2S concentration on the crystallinity of the CZTSSe thin films is also discussed.

  15. Spectroscopic studies on photoelectron transfer from 2-(furan-2-yl)-1-phenyl-1H-phenanthro[9,10-d]imidazole to ZnO, Cu-doped ZnO and Ag-doped ZnO.

    Science.gov (United States)

    Thanikachalam, V; Arunpandiyan, A; Jayabharathi, J; Karunakaran, C; Ramanathan, P

    2014-09-01

    The 2-(furan-2-yl)-1-phenyl-1H-phenanthro[9,10-d]imidazole [FPI] has been designed and synthesized as fluorescent sensor for nanoparticulate ZnO. The present work investigates the photoelectron transfer (PET) from FPI to ZnO, Cu-doped ZnO and Ag- doped ZnO nanoparticles using electronic and life time spectral measurements. Broad absorption along with red shift indicates the formation of charge-transfer complex [FPI-Nanoparticles]. The photophysical studies indicate lowering of HOMO and LUMO energy levels of FPI on adsorption on ZnO due to FPI- ZnO interaction. The obtained binding constant implies that the binding of FPI with nanoparticles was influenced by the surface modification of ZnO nanoparticles with Cu and Ag.

  16. Transport properties of microwave sintered pure and glass added MgCuZn ferrites

    Energy Technology Data Exchange (ETDEWEB)

    Madhuri, W., E-mail: madhuriw12@gmail.com [School of Advanced Sciences, VIT University, Vellore 632 014 (India); Penchal Reddy, M.; Kim, Il Gon [Department of Physics, Changwon National University, Changwon 641 773 (Korea, Republic of); Rama Manohar Reddy, N. [Department of Materials Science and Nanotechnology, Yogi Vemana University, Kadapa 516 227 (India); Siva Kumar, K.V. [Ceramic Composites Materials Laboratory, Sri Krishnadevaraya University, Anantapur 515 055 (India); Murthy, V.R.K. [Microwave Laboratory, IIT Madras, Chennai 600 036 (India)

    2013-07-01

    Highlights: • MgCuZn ferrite was successfully prepared by novel microwave sintering (MS) method. • The sintering temperature was notably reduced from 1150 °C to 950 °C for MS. • Temperature dependence of DC conductivity and AC conductivity are studied. • 1 wt% PBS glass added MS MgCuZn ferrite samples are suitable for core materials in multilayer chip inductors (MLCI). -- Abstract: A series of pure stoichiometric and 1 wt% lead borosilicate (PBS) glass added MgCuZn ferrite with the general formula Mg{sub 0.5}Cu{sub x}Zn{sub 0.5−x}Fe{sub 2}O{sub 4} with x = 0.05, 0.1, 0.15, 0.2, 0.25 and 0.3 were synthesized by microwave sintering technique. Single phase spinel structure is exhibited by the XRD patterns of these ferrites. DC and AC conductivity were investigated as a function of composition, temperature and frequency. DC conductivities were also estimated using the impedance spectroscopy analysis of Cole–Cole plots. The DC conductivities thus obtained are in good agreement with the experimental results. All the investigated samples exhibited two regions of conductivity one in the low temperature and the second in the high temperature region. It is observed that PBS glass added samples have lower conductivities than pure samples. Due to their lower conductivities and sintering temperatures the 1 wt% PBS glass added samples are suitable for multilayer chip inductor (MLCI) and high definition TV deflection yoke material application.

  17. Selective precipitation of Cu from Zn in a pS controlled continuously stirred tank reactor

    NARCIS (Netherlands)

    Sampaio, R.M.; Timmers, R.A.; Xu, Y.; Keesman, K.J.; Lens, P.N.L.

    2009-01-01

    Copper was continuously and selectively precipitated with Na2S to concentrations below 0.3 ppb from water containing around 600 ppm of both Cu and Zn in a Continuously Stirred Tank Reactor. The pH was controlled at 3 and the pS at 25 (pS = ¿log(S2¿)) by means of an Ag2S sulfide selective electrode.

  18. Crystallographic mechanism of inverse twinning in ordered β′-CuZn alloy

    Institute of Scientific and Technical Information of China (English)

    毛卫民

    2000-01-01

    The basic process of mechanical twinning in β’-CuZn phase, as an example of B2 structured metals, has been analyzed under the rolling stresses. The behavior of inverse twinning in B2 structured metals is discussed in terms of mechanics and crystallographic stability. It is shown that the inverse twinning could remain the B2 structure, and the resulting strains will have the lowest resistance during the rolling deformation of the polycrystalline.

  19. Crystallographic mechanism of inverse twinning in ordered β'-CuZn alloy

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The basic process of mechanical twinning in β'-CuZn phase, as an example of B2 structured metals, has been analyzed under the rolling stresses. The behavior of inverse twinning in B2 structured metals is discussed in terms of mechanics and crystallographic stability. It is shown that the inverse twinning could remain the B2 structure, and the resulting strains will have the lowest resistance during the rolling deformation of the polycrystalline.

  20. EDTA and citric acid mediated phytoextraction of Zn, Cu, Pb and Cd through marigold (Tagetes erecta).

    Science.gov (United States)

    Sinhal, V K; Srivastava, Alok; Singh, V P

    2010-05-01

    Phytoextraction is an emerging cost-effective solution for remediation of contaminated soils which involves the removal of toxins, especially heavy metals and metalloids, by the roots of the plants with subsequent transport to aerial plant organs. The aim of the present investigation is to study the effects of EDTA and citric acid on accumulation potential of marigold (Tagetes erecta) to Zn, Cu, Pb, and Cd and also to evaluate the impacts of these chelators (EDTA and citric acid) in combination with all the four heavy metals on the growth of marigold. The plants were grown in pots and treated with Zn (7.3 mg l(-1)), Cu (7.5 mg I(-1)), Pb (3.7 mg l(-1)) and Cd (0.2 mg l(-1)) alone and in combination with different doses of EDTA i.e., 10, 20 and 30 mg l(-1). All the three doses of EDTA i.e., 10, 20 and 30 mg l(-1) significantly increased the accumulation of Zn, Cu, Pb and Cd by roots, stems and leaves as compared to control treatments. The 30 mg l(-1) concentration of citric acid showed reduced accumulation of these metals by root, stem and leaves as compared to lower doses i.e., 10 and 20 mg l(-1). Among the four heavy metals, Zn accumulated in the great amount (526.34 mg kg(-1) DW) followed by Cu (443.14 mg kg(-1) DW), Pb (393.16 mg kg(-1) DW) and Cd (333.62 mg kg(-1) DW) in leaves with 30 mg l(-1) EDTA treatment. The highest concentration of EDTA and citric acid (30 mg l(-1)) caused significant reduction in growth of marigold in terms of plant height, fresh weight of plant, total chlorophyll, carbohydrate content and protein content. Thus EDTA and citric acid efficiently increased the phytoextractability of marigold which can be used to remediate the soil contaminated with these metals.

  1. Cloning and constitutive expression of Deschampsia antarctica Cu/Zn superoxide dismutase in Pichia pastoris

    Directory of Open Access Journals (Sweden)

    Gidekel Manuel

    2009-10-01

    Full Text Available Abstract Background Deschampsia antarctica shows tolerance to extreme environmental factors such as low temperature, high light intensity and an increasing UV radiation as result of the Antarctic ozone layer thinning. It is very likely that the survival of this species is due to the expression of genes that enable it to tolerate high levels of oxidative stress. On that account, we planned to clone the D. antarctica Cu/ZnSOD gene into Pichia pastoris and to characterize the heterologous protein. Findings The Copper/Zinc superoxide dismutase (Cu/ZnSOD gene, SOD gene, was isolated from a D. antarctica by cDNA library screening. This SOD gene was cloned in the expression vector pGAPZαA and successfully integrated into the genome of the yeast P. pastoris SMD1168H. A constitutive expression system for the expression of the recombinant SOD protein was used. The recombinant protein was secreted into the YPD culture medium as a glycosylated protein with a 32 mg/l expression yield. The purified recombinant protein possesses a specific activity of 440 U/mg. Conclusion D. antarctica Cu/ZnSOD recombinant protein was expressed in a constitutive system, and purified in a single step by means of an affinity column. The recombinant SOD was secreted to the culture medium as a glycoprotein, corresponding to approximately 13% of the total secreted protein. The recombinant protein Cu/ZnSOD maintains 60% of its activity after incubation at 40°C for 30 minutes and it is stable (80% of activity between -20°C and 20°C. The recombinant SOD described in this study can be used in various biotechnological applications.

  2. [Determination of Ag, Cu, Zn and Cd in silver brazing filler metals by ICP-AES].

    Science.gov (United States)

    Yang, X

    1997-06-01

    A method of simultaneous and direct determination for Ag, Cu, Zn and Cd in silver brazing filler metals by ICP-AES is reported. The spectral interferences and effect of acidity have been investigated. Working conditions were optimized. The method has been applied to the analysis of silver brazing filler metals with RSD of 4-7% and recovery of 94-105%. This method was accurate, simple and rapid.

  3. Research on Microstructure and Properties of AgCuZnNi Alloy%AgCuZnNi合金的显微组织与性能研究

    Institute of Scientific and Technical Information of China (English)

    陈永泰; 谢明; 杨有才; 张吉明; 王松; 王塞北; 胡洁琼; 李爱坤

    2015-01-01

    对AgCuZnNi合金的物相以及变形过程中合金的显微组织、力恘、电恘性能进行了悁究.悁究结果表明:合金主要由富Ag固溶体以及富Cu相组成,Zn与Ni主要存在于富Cu相中.变形量较小时,基体中的富Cu相发生位移、转动和破碎,随着变形量的继恋增加,大颗粒的富Cu相先产生变形,最后全部转变为纤维组织.抗拉强度和硬度随变形量的增加而增加,是形变强化、晶界强化和纤维强化共同作用的结果.电阻率随变形量的增加而增加,晶体缺陷及界面增多是电阻率增加的主要原因.%The phase composition and microstructure, mechanical properties, electrical properties during deformation of AgCuZnNi alloy were analyzed. The results show that the AgCuZnNi alloy is mainly composed of silver-rich phase and copper-rich phase, Zn and Ni mainly exist in copper-rich phase. The displacement, rotation and broken of the copper-rich phase take place only when the deformation is small. With the increase of deformation, large particles of copper-rich phase first produce deformation, finally, all particles of copper-rich phase completely convert to fibrous tissue. Tensile strength and hardness increase with the increase of deformation, which attributed to the joint actions of deformation strengthening, grain boundary strengthening and fiber strengthening. Resistivity decreases with the increase of deformation, due to the increase of crystal defects and grain boundary.

  4. Fundamental Studies of Methanol Synthesis from CO2 Hydrogenation on Cu(111), Cu Clusters, and Cu/ZnO(000ī)

    Energy Technology Data Exchange (ETDEWEB)

    Liu, P.; Yang, Y.; Evans, J.; Rodriguez, J.A.; White, M.G.

    2010-06-21

    A combination of experimental and theoretical methods were employed to investigate the synthesis of methanolvia CO{sub 2}hydrogenation (CO{sub 2} + 3H{sub 2} {yields} CH{sub 3}OH + H{sub 2}O) on Cu(111) and Cunanoparticle surfaces. High pressure reactivity studies show that Cunanoparticles supported on a ZnO(000{bar 1}) single crystal exhibit a higher catalytic activity than the Cu(111) planar surface. Complementary density functional theory (DFT) calculations of methanol synthesis were also performed for a Cu(111) surface and unsupported Cu{sub 29} nanoparticles, and the results support a higher activity for Cu nanoparticles. The DFT calculations show that methanol synthesis on Cu surfaces proceeds through a formate intermediate and the overall reaction rate is limited by both formate and dioxomethylene hydrogenation. Moreover, the superior activity of the nanoparticle is associated with its fluxionality and the presence of low-coordinated Cu sites, which stabilize the key intermediates, e.g. formate and dioxomethylene, and lower the barrier for the rate-limiting hydrogenation process. The reverse water-gas-shift (RWGS) reaction (CO{sub 2} + H{sub 2} {yields} CO + H{sub 2}O) was experimentally observed to compete with methanol synthesis and was also considered in our DFT calculations. In agreement with experiment, the rate of the RWGS reaction on Cu nanoparticles is estimated to be 2 orders of magnitude faster than methanol synthesis at T = 573 K. The experiments and calculations also indicate that CO produced by the fast RWGS reaction does not undergo subsequent hydrogenation to methanol, but instead simply accumulates as a product. Methanol production from CO hydrogenation via the RWGS pathway is hindered by the first hydrogenation of CO to formyl, which is not stable and prefers to dissociate into CO and H atoms on Cu. Our calculated results suggest that the methanol yield over Cu-based catalysts could be improved by adding dopants or promoters which are able

  5. Zn-VI/Cu2O Heterojunctions for Earth-Abundant Photovoltaics

    Science.gov (United States)

    Wilson, Samantha

    The need for sustainable energy production motivates the study of photovoltaic materials, which convert energy from sunlight directly into electricity. This work has focused on the development of Cu2O as an earth-abundant solar absorber due to the abundance of its constituent elements in the earth's crust, its suitable band gap, and its potential for low cost processing. Crystalline wafers of Cu2O with minority carrier diffusion lengths on the order of microns can be manufactured in a uniquely simple fashion --- directly from copper foils by thermal oxidation. Furthermore, Cu2Ohas an optical band gap of 1.9 eV, which gives it a detailed balance energy conversion efficiency of 24.7% and the possibility for an independently connected Si/Cu 2O dual junction with a detailed balance efficiency of 44.3%. However, the highest energy conversion efficiency achieved in a photovoltaic device with a Cu2O absorber layer is currently only 5.38% despite the favorable optical and electronic properties listed above. There are several challenges to making a Cu2O photovoltaic device, including an inability to dope the material, its relatively low chemical stability compared to other oxides, and a lack of suitable heterojunction partners due to an unusually small electron affinity. We have addressed the low chemical stability, namely the fact that Cu2O is an especially reactive oxide due to its low enthalpy of formation (DeltaHf0 = -168.7 kJ/mol), by developing a novel surface preparation technique. We have addressed the lack of suitable heterojunction partners by investigating the heterojunction band alignment of several Zn-VI materials with Cu 2O. Finally, We have addressed the typically high series resistance of Cu2O wafers by developing methods to make very thin, bulk Cu 2O, including devices on Cu2O wafers as thin as 20 microns. Using these methods we have been able to achieve photovoltages over 1 V, and have demonstrated the potential of a new heterojunction material, Zn(O,S).

  6. Interface band gap narrowing behind open circuit voltage losses in Cu2ZnSnS4 solar cells

    DEFF Research Database (Denmark)

    Crovetto, Andrea; Palsgaard, Mattias Lau Nøhr; Gunst, Tue

    2017-01-01

    We present evidence that bandgap narrowing at the heterointerface may be a major cause of the large open circuit voltage deficit of Cu2ZnSnS4/CdS solar cells. Bandgap narrowing is caused by surface states that extend the Cu2ZnSnS4valence band into the forbidden gap. Those surface states are consi......We present evidence that bandgap narrowing at the heterointerface may be a major cause of the large open circuit voltage deficit of Cu2ZnSnS4/CdS solar cells. Bandgap narrowing is caused by surface states that extend the Cu2ZnSnS4valence band into the forbidden gap. Those surface states...... Zn to passivate those surface states. Focusing future research on Zn-based buffers is expected to significantly improve the open circuit voltage and efficiency of pure-sulfide Cu2ZnSnS4 solar cells....

  7. Gene Expression and Activities of SOD in Cucumber Seedlings Were Related with Concentrations of Mn2+,Cu2+,or Zn2+ Under Low Temperature Stress

    Institute of Scientific and Technical Information of China (English)

    GAO Jun-jie; LI Tao; YU Xian-chang

    2009-01-01

    Effects of increasing Mn2+,Cu2+,or Zn2+ on SOD expressions were studied in cucumber seedlings under low temperature stress.Both gene expressions and activities of Cu/Zn-SOD and Mn-SOD in cucumber seedling leaves were induced by increasing Mn2+,Cu2+,or Zn2+ under low temperature stress,especially 48 h afterwards.The activities of Cu/Zn-SOD and Mn-SOD at 0 and 48 h after treatment were in accordance with their gene expression levels,which implied that the transcriptional regulation plays key roles in regulating their activities at the early stage of low temperature stress.Gene expressions of Cu/Zn-SOD and Mn-SOD declined at 96 h,but Cu/Zn-SOD and Mn-SOD activities still remain high,which suggested that Cu/Zn-SOD and Mn-SOD activities might be regulated by other factors after transcription at the later stage of low temperature stress.Therefore,we concluded that the increasing Mn2+,Cu2+,or Zn2+ could increase the capacity of scavenging ROS in cucumber seedlings under low temperature stress by inducing gene expressions of Cu/Zn-SOD and Mn-SOD,elevating activities of Cu/Zn-SOD,Mn-SOD,or regulating other factors after transcription.

  8. Low-temperature sintering method for NiCuZn ferrite and effect of Mn addition on electromagnetic properties

    Institute of Scientific and Technical Information of China (English)

    JU Dong-ying; BIAN Pei

    2006-01-01

    Low temperature sintering NiCuZn ferrite was employed at most cases due to its co-firability with Ag (below 960 ℃). The NiCuZn ferrite sintered body with high-strength and high-frequency magnetic properties was fabricated. Firstly,NiCuZn ferrite powder was synthesized under CO2 atmosphere at 500 ℃ from the mixed doxalate synthesized by liquid phase precipitation method. Then a small amount of boric acid (H3BO3) was added to the powder,and the NiCuZn ferrite powder compact was prepared with Newton press and CIP methods. Finally,NiCuZn ferrite sintered body was fabricated by sintering at 900 ℃ under CO2 atmosphere. The minimum sintering temperature (800 ℃) was determined by the study of high temperature shrinkage. By this method,NiCuZn ferrite sintered body with 0.5% (mass fraction) boric acid was obtained,which has the bending strength of 340 MPa. The effect of various Mn addition on electromagnetic properties were studied.

  9. The structural, optical, and electrical properties of vacuum evaporated Cu-doped ZnTe polycrystalline thin films

    Science.gov (United States)

    Feng, L.; Mao, D.; Tang, J.; Collins, R. T.; Trefny, J. U.

    1996-09-01

    We have studied the structural, optical, and electrical properties of thermally evaporated, Cu-doped, ZnTe thin films as a function of Cu concentration and post-deposition annealing temperature. X-ray diffraction measurements showed that the ZnTe films evaporated on room temperature substrates were characterized by an average grain size of 300Å with a (111) preferred orientation. Optical absorption measurements yielded a bandgap of 2.21 eV for undoped ZnTe. A bandgap shrinkage was observed for the Cu-doped films. The dark resistivity of the as-deposited ZnTe decreased by more than three orders of magnitude as the Cu concentration was increased from 4 to 8 at.% and decreased to less than 1 ohm-cm after annealing at 260°C. For films doped with 6 7 at.% Cu, an increase of resistivity was also observed during annealing at 150 200°C. The activation energy of the dark conductivity was measured as a function of Cu concentration and annealing temperature. Hall measurements yielded hole mobility values in the range between 0.1 and 1 cm2/V·s for both as-deposited and annealed films. Solar cells with a CdS/CdTe/ZnTe/metal structure were fabricated using Cudoped ZnTe as a back contact layer on electrodeposited CdTe. Fill factors approaching 0.75 and energy conversion efficiencies as high as 12.1% were obtained.

  10. Increased glycated Cu,Zn-superoxide dismutase levels in erythrocytes of patients with insulin-dependent diabetis mellitus.

    Science.gov (United States)

    Kawamura, N; Ookawara, T; Suzuki, K; Konishi, K; Mino, M; Taniguchi, N

    1992-06-01

    Our previous study indicated that erythrocyte Cu,Zn-superoxide dismutase (Cu,Zn-SOD) undergoes glycation and inactivation in vivo (1) and in vitro (2). The aim of the present study was to assess glycated Cu,Zn-SOD in patients with insulin-dependent diabetes mellitus. Glycated Cu,Zn-SOD, which binds to a boronic acid affinity column, was measured by the enzyme-linked immunosorbent assay. The percentage of the glycated form in 25 insulin-dependent diabetic children was 40.2 +/- 8.2%; this was significantly higher than that in the normal controls (P less than 0.01). The specific activity of the glycated form in the diabetic children was 163,000 +/- 33,000 IU/mg Cu,Zn-SOD protein, significantly lower than that in controls (P less than 0.01). These data indicate that glycated and less active Cu,Zn-SOD is increased in erythrocytes of patients with insulin-dependent diabetes mellitus.

  11. Spatial and temporal variations in inhalable CuZnPb aerosols within the Mexico City pollution plume.

    Science.gov (United States)

    Moreno, T; Querol, X; Pey, J; Minguillón, M C; Pérez, N; Alastuey, A; Bernabé, R M; Blanco, S; Cárdenas, B; Eichinger, W; Salcido, A; Gibbons, W

    2008-03-01

    We report on the CuPbZn content of PM10 and PM2.5 samples collected from three sites (urban T0, suburban T1 and rural T2) during the Mexico City MILAGRO campaign of March 2006. Daytime city centre concentrations of summation operator CuZnPb(PM10) were much higher (T0 > 450 ng m(-3)) than at the suburban site (T1 inversion layer, but decreased at the rural site. Transient spikes in concentrations of different metals, e.g. a "copper event" at T0 (CuPM10 281 ng m(-3)) and "zinc event" at T1 (ZnPM10 1481 ng m(-3)) on the night of March 7-8, demonstrate how industrial pollution sources produce localised chemical inhomogeneities in the city atmosphere. Most metal aerosols are <2.5 microm and SEM study demonstrates the dominance of Fe, Ti, Ba, Cu, Pb and Zn (and lesser Sn, Mo, Sb, W, Ni, V, As, Bi) in metalliferous particles that have shapes including spherical condensates, efflorescent CuZnClS particles, cindery Zn, and Cu wire. Metal aerosol concentrations do not change in concert with PM10 mass, which is more influenced by wind resuspension than industrial emissions. Metalliferous particles can induce cell damage, and PM composition is probably more important than PM mass, with respect to negative health effects, so that better monitoring and control of industrial emissions would likely produce significant improvements in air quality.

  12. Response of Pinus halepensis Mill. seedlings to biosolids enriched with Cu, Ni and Zn in three Mediterranean forest soils

    Energy Technology Data Exchange (ETDEWEB)

    Fuentes, David [Fundacion CEAM, Universidad de Alicante, Ap 99, 03080 Alicante (Spain)]. E-mail: david.fuentes@ua.es; Disante, Karen B. [Dept. d' Ecologia, Universitat d' Alacant, Ap 99, 03080 Alicante (Spain)]. E-mail: kb.disante@ua.es; Valdecantos, Alejandro [Fundacion CEAM, Universidad de Alicante, Ap 99, 03080 Alicante (Spain) and Dept. Ecosistemas Agroforestales (EPS Gandia), Universidad Politecnica de Valencia. Ctra. Nazaret-Oliva s/n. 46730 Gandia, Valencia (Spain)]. E-mail: a.valdecantos@ua.es; Cortina, Jordi [Dept. d' Ecologia, Universitat d' Alacant, Ap 99, 03080 Alicante (Spain)]. E-mail: jordi@ua.es; Ramon Vallejo, V. [Fundacion CEAM, Universidad de Alicante, Ap 99, 03080 Alicante (Spain)]. E-mail: ramonv@ceam.es

    2007-01-15

    We investigated the response of Pinus halepensis seedlings to the application of biosolids enriched with Cu, Ni and Zn on three Mediterranean forest soils under semiarid conditions. One-year-old seedlings were planted in lysimeters on soils developed from marl, limestone and sandstone which were left unamended, amended with biosolids, or amended with biosolids enriched in Cu, Ni and Zn. Enriched biosolids increased plant heavy metal concentration, but always below phytotoxic levels. Seedlings receiving unenriched biosolids showed a weak reduction in Cu and Zn concentration in needles, negatively affecting physiological status during drought. This effect was alleviated by the application of enriched sludge. Sewage sludge with relatively high levels of Cu, Zn and Ni had minor effects on plant performance on our experimental conditions. Results suggest that micronutrient limitations in these soils may be alleviated by the application of biosolids with a higher Cu, Zn and Ni content than those established by current regulations. - Biosolid-borne Cu, Ni and Zn did not show negative effects on Pinus halepensis seedlings performance after application on three Mediterranean forest soils.

  13. Role of ZnO in Reduction Process of CuO-Based Catalyst for Methanol Synthesis%ZnO在CuO基甲醇合成催化剂还原过程中的作用

    Institute of Scientific and Technical Information of China (English)

    郭宪吉; 宋连卿; 郭益群

    1999-01-01

    用一步并流共沉淀法制备了一系列具有不同组成的CuO基样品,并测试了它们在合成甲醇反应中的活性.利用TG-DTG手段,对各CuO基样品的还原过程进行了考察,结果表明,ZnO组分对催化剂CuO-ZnO-Al2O3的还原行为有重要影响.依据Coats-Redfern处理方法获得了CuO基样品的还原动力学参数%A series of CuO-based samples with different compositions have been prepared and their catalytic activities for methanol synthesis have been tested.By means of TG-DTG,the reduction process of CuO-based Samples were investigated.The results indicated that the ZnO component affected the reduction behavior of the CuO-ZnO-Al2O3 sample significantly.By using Coats-Redfern,the kinetic parameters of reduction of the CuO-based samples were obtained.

  14. Optical and Electrical Properties of TTF-MPcs (M = Cu, Zn Interfaces for Optoelectronic Applications

    Directory of Open Access Journals (Sweden)

    María Elena Sánchez-Vergara

    2015-11-01

    Full Text Available Sandwich structures were fabricated by a vacuum deposition method using MPc (M = Cu, Zn, with a Tetrathiafulvalene (TTF derivative, and Indium Tin Oxide (ITO and aluminum electrodes. The structure and morphology of the deposited films were studied by IR spectroscopy, scanning electron microscopy (SEM and energy dispersive spectroscopy (EDS. The absorption spectra of TTF derivative-MPc (M = Cu, Zn thin films deposited at room temperature were recorded in the spectral range 200–1000 nm. The optical band gap of the thin films was determined from the (αhν1/2 vs. hν plot. The direct-current (DC electrical properties of the glass/ITO/TTFderiv-MPc (M = Cu, Zn/Al structures were also investigated. Changes in conductivity of the derivative-TTF-enriched Pc compounds suggest the formation of alternative paths for carrier conduction. At low voltages, forward current density obeys an ohmic I-V relationship; at higher voltages, conduction is mostly due to a space-charge-limited conduction (SCLC mechanism.

  15. Stability of Hume-Rothery phases in Cu Zn alloys at pressures up to 50 GPa

    Science.gov (United States)

    Degtyareva, V. F.; Degtyareva, O.; Sakharov, M. K.; Novokhatskaya, N. I.; Dera, P.; Mao, H. K.; Hemley, R. J.

    2005-12-01

    The crystal structure of the γ-brass phase Cu5Zn8 is confirmed with single-crystal x-ray diffraction and CCD detector to be cubic with 52 atoms in the unit cell, space group I\\bar {4}3m , and the refined atomic positions are in good agreement with previously reported data. The structural behaviour of α-(fcc), β-(bcc), and γ-brass (cI52) phases of the Cu-Zn alloy system has been studied under pressure using diamond anvil cells and powder x-ray diffraction with synchrotron radiation. The appearance of additional peaks in the diffraction patterns of α- and β-phases indicates the beginning of transitions to new phases at 17 and 37 GPa, respectively. The complex cubic γ-brass phase is observed to be stable up to at least 50 GPa. The bulk modulus K0 was determined as 140(4) GPa for α-, 139(5) GPa for β-, and 121(2) GPa for γ-phase assuming K0' = 4. The structural stability of brass phases of the Cu-Zn system under pressure is discussed in terms of a Hume-Rothery mechanism.

  16. Evaluation of the bioaccessible fractions of Fe, Zn, Cu and Mn in baby foods.

    Science.gov (United States)

    do Nascimento da Silva, Emanueli; Leme, Ana Beatriz Perriello; Cidade, Mirla; Cadore, Solange

    2013-12-15

    The bioaccessibility of four essential micronutrients (iron, zinc, copper and manganese) in some baby foods was evaluated using an in vitro gastrointestinal digestion model. For all of the flour-based foods evaluated, the bioaccessibility of Zn was low, while the bioaccessibility of Cu was above 50%. For these samples, the bioaccessibility of Mn was lower than 50%. Two samples composed of oat and rice flour and whole wheat flour demonstrated a lower bioaccessible fraction of Fe (less than 35%), while the sample made with wheat flour showed high Fe bioaccessibility (approximately 80%). For vegetable- and meat-based baby foods, the Fe bioaccessibility was greater than 80% in samples that contained meat and chicken and approximately 20% for the banana-based sample. The bioaccessibility of Zn was small for all of the foods studied, and in some cases, no Zn appeared to be released. The sample containing banana showed 100% Cu bioaccessibility, in contrast to meat and chicken-based samples, whose Cu bioaccessibility values were less than 50%. The opposite effect occurred for Mn, in which samples containing meat and chicken presented a bioaccessible fraction greater than 50% while the banana-based sample had a fraction less than 50%. © 2013 Elsevier B.V. All rights reserved.

  17. Formulation and Characterization of Cu Doped ZnO Thick Films as LPG Gas Sensor

    Directory of Open Access Journals (Sweden)

    A. V. PATIL

    2010-12-01

    Full Text Available Thick films of pure and various concentrations (1 wt. %, 3 wt. %, 5 wt. %, 7 wt. % and 10 wt. % of Cu-doped ZnO were prepared on alumina substrates using a screen printing technique. These films were fired at a temperature of 700ºC for two hours in an air atmosphere. Morphological, compositional and structural properties of the samples were obtained using the scanning electron microscopy (SEM, Energy dispersive spectroscopy (EDAX and X-ray diffraction techniques respectively. The LPG gas sensing properties of these thick films were investigated at different operating temperatures and LPG gas concentrations. The surface resistance of thick films decreases when exposed to LPG gas. The Cu doped films show significant sensitivity to LPG gas than pure ZnO film. 5 wt. % Cu-doped ZnO film was found to be more sensitive (87.3 % to LPG gas exposed at 300 oC than other doping concentrations with fast response and recovery time.

  18. The microstructure and mechanical properties of the alloy CuZn30 after recrystallizion annealing

    Directory of Open Access Journals (Sweden)

    W. Ozgowicz

    2010-05-01

    Full Text Available Purpose: The aim of the investigations is to determine the influence of the recrystallization temperature on the microstructure and mechanical properties of the brass CuZn30 subjected to cold deformation in the process of rolling at various degrees of strain.Design/methodology/approach: The brass CuZn30 was recrystallization annealed within the temperature range of 300-650°C after cold rolling with the strain of 15.8-70.2%. The tensile test was carried out by the use of universal testing machine. Metallographic observations were performed on an optical microscope and fractographic tests on a scanning electron microscope. The hardness was also measured.Findings: The analysis of the results of investigations concerning the mechanical properties permitted to determine the effect of the temperature of recrystallization annealing on the strength and plastic properties of the investigated brass, subjected to cold deformation with a varying strain in the course of rolling. The character of fracture after decohesion in the tension test was determined basing on fractographic investigations.Practical implications: An increase of the recrystallization temperature within the range of 400-650°C results in a deterioration of the mechanical properties of the brass CuZn30 and an increase of its plastic properties.Originality/value: The results of the investigation revealed the occurrence of the phenomenon of heterogeneous plastic deformation in the recrystallized alloy.

  19. Removal of Cu (II and Zn (II from water with natural adsorbents from cassava agroindustry residues

    Directory of Open Access Journals (Sweden)

    Daniel Schwantes

    2015-07-01

    Full Text Available Current study employs solid residues from the processing industry of the cassava (Manihot esculenta Crantz (bark, bagasse and bark + bagasse as natural adsorbents for the removal of metal ions Cu(II and Zn(II from contaminated water. The first stage comprised surface morphological characterization (SEM, determination of functional groups (IR, point of zero charge and the composition of naturally existent minerals in the biomass. Further, tests were carried out to evaluate the sorption process by kinetic, equilibrium and thermodynamic studies. The adsorbents showed a surface with favorable adsorption characteristics, with adsorption sites possibly derived from lignin, cellulose and hemicellulose. The dynamic equilibrium time for adsorption was 60 min. Results followed pseudo-second-order, Langmuir and Dubinin-Radushkevich models, suggesting a chemisorption monolayer. The thermodynamic parameters suggested that the biosorption process of Cu and Zn was endothermic, spontaneous or independent according to conditions. Results showed that the studied materials were potential biosorbents in the decontamination of water contaminated by Cu(II and Zn(II. Thus, the above practice complements the final stages of the cassava production chain of cassava, with a new disposal of solid residues from the cassava agroindustry activity.

  20. Microwave sintering versus conventional sintering of NiCuZn ferrites. Part I: Densification evolution

    Science.gov (United States)

    Zhu, Jianhua; Ouyang, Chenxin; Xiao, Shumin; Gao, Yongyi

    2016-06-01

    This work reports the recent study on the microwave sintering (MS) versus conventional sintering (CS) of NiCuZn ferrites, with particular interests in the densification evolution. NiCuZn ferrite powders were synthesized through the solid state reaction route. Densification behaviors of ferrite samples under the two types of thermal sources were monitored in real-time. Meanwhile, the influences of additives (1 wt% BSZ glass or 1 wt% Bi2O3) on the densifications were also investigated. Both constant heating rate (CHR) and master sintering curve (MSC) models were used to evaluate the sintering activation energy (Q). Results demonstrated that the microwave-enhanced diffusion mainly occurs at the intermediate sintering stage. The Q-value estimated by MSC method agreed well with that from CHR method. With the influence of microwave electromagnetic field, the activation energy of NiCuZn ferrites was decreased by roughly 100-150 kJ/mol. In addition, doping a small amount of additives could improve densification degree and reduce the minimal energy to activate diffusion mechanisms.

  1. 利用Cu2SnS3纳米晶和Zn离子混合溶液制备Cu2ZnSnS4薄膜%Synthesis of Cu2ZnSnS4 thin film from mixed solution of Cu2SnS3 nanoparticles and Zn ions

    Institute of Scientific and Technical Information of China (English)

    童正夫; 杨佳; 颜畅; 郝萌萌; 刘芳洋; 蒋良兴; 赖延清; 李劼; 刘业翔

    2016-01-01

    在非真空条件下,选用无毒原材料,采用溶液法制备Cu2ZnSnS4薄膜。利用透射电镜、X射线衍射、扫描电镜、能谱以及拉曼等研究手段,对Cu2ZnSnS4薄膜的形成机理进行分析。通过循环伏安及光电测试,探讨Cu2ZnSnS4薄膜作为染料敏化太阳能电池对电极的催化性能。结果表明:采用溶液法制备的Cu2ZnSnS4混合前驱体溶液主要由Cu2SnS3纳米晶和Zn离子组成,将其滴涂成膜后,经过550°C退火,最终可以得到Cu2ZnSnS4薄膜;制备的Cu2ZnSnS4薄膜对氧化还原对I3−/I−具有一定的催化作用,将其应用于染料敏化太阳能电池的对电极取得了1.09%的光电转化效率。%The Cu2ZnSnS4 thin film was prepared by a facile solution method without vacuum environment and toxic substance. The formation mechanism of the film was studied by transmission electron microscopy (TEM), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and Raman scattering measurements. Through cyclic voltammetry and photo-electricity tests, the electrocatalytic activity of the prepared film as the counter electrode of dye-sensitized solar cell was also studied. The results show that the mixed precursor solution mainly consists of Cu2SnS3 nanoparticles and Zn ions. After 550 °C annealing process on the precursor film prepared from the mixed solution, Cu2ZnSnS4 thin film is obtained. Besides, it is found that the prepared Cu2ZnSnS4 thin film has the electrocatalytic activity toward the redox reaction of I3−/I− and the dye-sensitized solar cell with the prepared Cu2ZnSnS4 thin film as the counter electrode achieves the efficiency of 1.09%.

  2. KCN Chemical Etch for Interface Engineering in Cu2ZnSnSe4 Solar Cells.

    Science.gov (United States)

    Buffière, Marie; Brammertz, Guy; Sahayaraj, Sylvester; Batuk, Maria; Khelifi, Samira; Mangin, Denis; El Mel, Abdel-Aziz; Arzel, Ludovic; Hadermann, Joke; Meuris, Marc; Poortmans, Jef

    2015-07-15

    The removal of secondary phases from the surface of the kesterite crystals is one of the major challenges to improve the performances of Cu2ZnSn(S,Se)4 (CZTSSe) thin film solar cells. In this contribution, the KCN/KOH chemical etching approach, originally developed for the removal of CuxSe phases in Cu(In,Ga)(S,Se)2 thin films, is applied to CZTSe absorbers exhibiting various chemical compositions. Two distinct electrical behaviors were observed on CZTSe/CdS solar cells after treatment: (i) the improvement of the fill factor (FF) after 30 s of etching for the CZTSe absorbers showing initially a distortion of the electrical characteristic; (ii) the progressive degradation of the FF after long treatment time for all Cu-poor CZTSe solar cell samples. The first effect can be attributed to the action of KCN on the absorber, that is found to clean the absorber free surface from most of the secondary phases surrounding the kesterite grains (e.g., Se0, CuxSe, SnSex, SnO2, Cu2SnSe3 phases, excepting the ZnSe-based phases). The second observation was identified as a consequence of the preferential etching of Se, Sn, and Zn from the CZTSe surface by the KOH solution, combined with the modification of the alkali content of the absorber. The formation of a Cu-rich shell at the absorber/buffer layer interface, leading to the increase of the recombination rate at the interface, and the increase in the doping of the absorber layer after etching are found to be at the origin of the deterioration of the FF of the solar cells.

  3. Solderability and intermetallic compounds formation of Sn-9Zn-xAg lead-free solders wetted on Cu substrate

    Institute of Scientific and Technical Information of China (English)

    CHEN Wenxue; XUE Songbai; WANG Hui; WANG Jianxin; HAN Zongjie

    2009-01-01

    The eutectie Sn-9Zn alloy was doped with Ag (0 wt.%-1 wt.%) to form Sn-9Zn-xAg lead-free solder alloys. The effect of the addition of Ag on the microstructure and solderability of this alloy was investigated and intermetallic compounds (IMCs) formed at the solder/Cu interface were also examined in this study. The results show that, due to the addition of Ag, the microstructure of the solder changes. When the quan-tity of Ag is lower than 0.3 wt.%, the needle-like Zn-rich phase decreases gradually. However, when the quantity of Ag is 0.5 wt.%-1 wt.%, Ag-Zn intermetallic compounds appear in the solder. In particular, adding 0.3 wt.% Ag improves the wetting behavior due to the better oxi-dation resistance of the Sn-9Zn solder. The addition of an excessive amount of Ag will deteriorate the wetting property because the gluti-nosity and fluidity of Sn-9Zn-(0.5, 1)Ag solder decrease. The results also indicate that the addition of Ag to the Sn-Zn solder leads to the pre-cipitation of ε-AgZn_3 from the liquid solder on preformed interracial intermetallics (Cu_5Zn_8). The peripheral AgZn_3, nodular on the Cu_5Zn_8 IMCs layer, is likely to be generated by a peritectic reaction L+γ-Ag_5Zn8→ε-AgZn_3 and the following crystallization of AgZn_3.

  4. Cu-doped ZnO nanoporous film for improved performance of CdS/CdSe quantum dot-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Myeong-Soo; Son, Min-Kyu; Kim, Soo-Kyoung; Park, Songyi; Prabakar, Kandasamy; Kim, Hee-Je, E-mail: heeje@pusan.ac.kr

    2014-11-03

    Copper (Cu) doped zinc oxide (ZnO) powders were synthesized by co-precipitation method with different at% (0 and 0.5 at%) of Cu dopant. Cu-doped ZnO nanoporous (NP) films were fabricated to enhance the performance of the ZnO based cadmium sulfide (CdS) and cadmium selenide (CdSe) quantum dot-sensitized solar cells (QDSSCs). The existence of Cu ions in the Cu-doped ZnO NP film was detected by X-ray fluorescence. The surface morphology, microstructure and crystal structure of Cu-doped ZnO NP films were analyzed by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The optical property of CdS/CdSe co-sensitized Cu-doped ZnO NP film was studied by UV–vis absorption spectroscopy. The photovoltaic performance and electrical property of Cu-doped ZnO CdS/CdSe QDSSCs were studied by current–voltage characteristic curves and electrochemical impedance spectroscopy under air mass 1.5 condition. As a result, short circuit current density and fill factor increased from 9.074 mA/cm{sup 2} and 0.403 to 9.865 mA/cm{sup 2} and 0.427 respectively, based on the enhanced absorbance and electron transport by Cu-doping. This led to the increasing light conversion efficiency from 2.27% to 2.61%. - Highlights: • Cu-doped ZnO powders were synthesized by co-precipitation method. • Cu-doped ZnO nanoporous films with high crystallinity were uniformly deposited. • Absorbance of Cu-doped ZnO nanoporous film was enhanced. • Electron conductivity of Cu-doped ZnO nanoporous film was enhanced. • Performance of Cu-doped ZnO CdS/CdSe QDSSC was improved.

  5. Synthesis of Zn-Cu-In-S/ZnS Core/Shell Quantum Dots with Inhibited Blue-Shift Photoluminescence and Applications for Tumor Targeted Bioimaging

    Directory of Open Access Journals (Sweden)

    Weisheng Guo, Na chen, Yu Tu, Chunhong Dong, Bingbo Zhang, Chunhong Hu, Jin Chang

    2013-01-01

    Full Text Available A facile strategy is reported here for synthesis of Zn-Cu-In-S/ZnS (ZCIS/ZnS core/shell QDs to address the synthetic issues that the unexpected blue-shift of CuInS2-based nanocrystals. In this strategy, Zn2+ ions are intentionally employed for the synthesis of alloyed ZCIS core QDs before ZnS shell coating, which contributes to the reduced blue-shift in photoluminescence (PL emission. The experimental results demonstrate this elaborate facile strategy is effective for the reduction of blue-shift during shell growth. Particularly, a hypothesis is proposed and proved for explanation of this effective strategy. Namely, both cation exchange inhibition and ions accumulation are involved during the synthesis of ZCIS/ZnS QDs. Furthermore, the obtained near infrared (NIR ZCIS/ZnS QDs are transferred into aqueous phase by a polymer coating technique and coupled with cyclic Arg-Gly-Asp peptide (cRGD peptides. After confirmation of biocompability by cytotoxicity test on normal 3T3 cells, these QDs are injected via tail vein into nude mice bearing U87 MG tumor. The result indicates that the signals detected in the tumor region are much more distinguishing injected with ZCIS/ZnS-cRGD QDs than that injected with ZCIS/ZnS QDs.

  6. Selenization of mixed metal oxides for dense and ZnSe-free Cu{sub 2}ZnSnSe{sub 4} absorber films

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Yitao; Chen, Guilin; Pan, Bin; Li, JianMin; Jiang, Guoshun; Liu, Weifeng, E-mail: liuwf@ustc.edu.cn; Zhu, Changfei, E-mail: cfzhu@ustc.edu.cn

    2014-04-05

    Highlights: • ZnSe-free CZTSe films with large grains was prepared from mixed oxides nanopraticles. • Appearance of Zn{sub 2}SnO{sub 4} in mixed oxides precursors leads to the absence of ZnSe secondary phrase. • To obtain pure CZTSe phase, different treating temperature was used. -- Abstract: Cu{sub 2}ZnSnSe{sub 4} (CZTSe) films were prepared by direct selenization of Cu{sub 2}O, SnO{sub 2} and Zn{sub 2}SnO{sub 4} precursors. Oxides precursors were prepared by baking hydroxides precipitation. In order to obtain ZnSe-free CZTSe films, Zn{sub 2}SnO{sub 4} was used to replace separated ZnO and SnO{sub 2} as one of the precursors. Through X-ray diffraction (XRD), scanning electron microscopy (SEM), it was found that CZTSe films, with micron-sized dense grains, were obtained in our work. From Raman spectra, it was also found that the ZnSe secondary phase was absent after the selenization. An energy bandgap about 0.86 eV was obtained in our work, which confirmed the Stannite-CZTSe structure.

  7. The competing roles of i-ZnO in Cu(In,Ga)Se2 solar cells

    NARCIS (Netherlands)

    Williams, B.L.; Zardetto, V.; Kniknie, B.; Verheijen, M.A.; Kessels, W.M.M.; Creatore, M.

    2016-01-01

    The electrical role of the highly resistive and transparent (HRT) i-ZnO layer in Cu(In, Ga)Se2(CIGS) solar cells is investigated. By tuning the resistivity of atomic layer deposited (ALD) i-ZnO through the use of post-growth O2-plasma treatments, it is shown that low i-ZnO carrier densities (i.e. hi

  8. Influence of Cu doping on the structural, electrical and optical properties of ZnO

    Indian Academy of Sciences (India)

    Arindam Ghosh; Navnita Kumari; Ayon Bhattacharjee

    2015-04-01

    Pure and Cu-doped zinc oxide (ZnO) nanoparticles were prepared using a chemical method. The dopant concentration (Cu/Zn in atomic percent