Note: This page contains sample records for the topic copper selenides from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: August 15, 2014.
1

Formation of copper-indium-selenide and/or copper-indium-gallium-selenide films from indium selenide and copper selenide precursors  

DOEpatents

Liquid-based indium selenide and copper selenide precursors, including copper-organoselenides, particulate copper selenide suspensions, copper selenide ethylene diamine in liquid solvent, nanoparticulate indium selenide suspensions, and indium selenide ethylene diamine coordination compounds in solvent, are used to form crystalline copper-indium-selenide, and/or copper indium gallium selenide films (66) on substrates (52).

Curtis, Calvin J. (Lakewood, CO); Miedaner, Alexander (Boulder, CO); Van Hest, Maikel (Lakewood, CO); Ginley, David S. (Evergreen, CO); Nekuda, Jennifer A. (Lakewood, CO)

2011-11-15

2

40 CFR 721.10391 - Copper gallium indium selenide.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Copper gallium indium selenide. 721.10391...Chemical Substances § 721.10391 Copper gallium indium selenide. (a) Chemical...The chemical substance identified as copper gallium indium selenide (PMN...

2013-07-01

3

Copper selenide nanocrystals for photothermal therapy.  

PubMed

Ligand-stabilized copper selenide (Cu(2-x)Se) nanocrystals, approximately 16 nm in diameter, were synthesized by a colloidal hot injection method and coated with amphiphilic polymer. The nanocrystals readily disperse in water and exhibit strong near-infrared (NIR) optical absorption with a high molar extinction coefficient of 7.7 × 10(7) cm(-1) M(-1) at 980 nm. When excited with 800 nm light, the Cu(2-x)Se nanocrystals produce significant photothermal heating with a photothermal transduction efficiency of 22%, comparable to nanorods and nanoshells of gold (Au). In vitro photothermal heating of Cu(2-x)Se nanocrystals in the presence of human colorectal cancer cell (HCT-116) led to cell destruction after 5 min of laser irradiation at 33 W/cm(2), demonstrating the viabilitiy of Cu(2-x)Se nanocrystals for photothermal therapy applications. PMID:21553924

Hessel, Colin M; Pattani, Varun P; Rasch, Michael; Panthani, Matthew G; Koo, Bonil; Tunnell, James W; Korgel, Brian A

2011-06-01

4

Copper Selenide Nanocrystals for Photothermal Therapy  

PubMed Central

Ligand-stabilized copper selenide (Cu2?xSe) nanocrystals, approximately 16 nm in diameter, were synthesized by a colloidal hot injection method and coated with amphiphilic polymer. The nanocrystals readily disperse in water and exhibit strong near infrared (NIR) optical absorption with a high molar extinction coefficient of 7.7 × 107 cm?1 M?1 at 980 nm. When excited with 800 nm light, the Cu2?xSe nanocrystals produce significant photothermal heating with a photothermal transduction efficiency of 22%, comparable to nanorods and nanoshells of gold (Au). In vitro photothermal heating of Cu2?xSe nanocrystals in the presence of human colorectal cancer cell (HCT-116) led to cell destruction after 5 minutes of laser irradiation at 33 W/cm2, demonstrating the viabilitiy of Cu2?xSe nanocrystals for photothermal therapy applications.

Hessel, Colin M.; Pattani, Varun; Rasch, Michael; Panthani, Matthew G.; Koo, Bonil; Tunnell, James W.; Korgel, Brian A.

2011-01-01

5

Use of Electrically Conducting Coatings of Copper Selenide and Coatings Composed of Cu3PSX for Preparing Electroluminescent Capacitors.  

National Technical Information Service (NTIS)

Methods of applying electrically conducting coatings of copper selenide and coatings with a composition of Cu3PSx to organic glass and transparent polymer ribbons are discussed. Copper selenide coatings are produced by vacuum deposition of Cu2Se. Heating ...

B. P. Kryzhanovskii B. L. Agranat B. M. Kruglov

1970-01-01

6

Controllable synthesis of copper selenide nanocrystals through a green paraffin-acetate method  

Microsoft Academic Search

Comparing with the other metal chalcogenide semiconductors, copper selenide has still not been well researched in nanoscience and nanotechnology, probably due to the difficulty in the controllable synthesis of its various phase. In the present work, Cu2??Se and CuSe were synthesized open to air through a green paraffin-acetate method. The morphology study indicated that the copper selenide mainly showed hexagonal

Aiyu Zhang; Qian Ma; Zhaoguang Wang; Mengkai Lu; Ping Yang; Guangjun Zhou

2010-01-01

7

Spectroscopic Ellipsometry Characterization of Variable Cu Concentration in Copper Indium Gallium di-Selenide Photovoltaic Films  

Microsoft Academic Search

Copper indium gallium di-selenide (CIGS) is among the most promising thin-film photovoltaic (PV) materials. Solar cells, using CIGS as an absorber layer, have achieved greater than 18 percent power conversion efficiencies on the laboratory scale. The best CIGS based photovoltaics have been created by utilizing the so-called three-stage process for the growth of the absorber layer. Standard substrates consist of

J. C. Verley; T. E. Furtak

2000-01-01

8

Metal ions to control the morphology of semiconductor nanoparticles: copper selenide nanocubes.  

PubMed

Morphology is a key parameter in the design of novel nanocrystals and nanomaterials with controlled functional properties. Here, we demonstrate the potential of foreign metal ions to tune the morphology of colloidal semiconductor nanoparticles. We illustrate the underlying mechanism by preparing copper selenide nanocubes in the presence of Al ions. We further characterize the plasmonic properties of the obtained nanocrystals and demonstrate their potential as a platform to produce cubic nanoparticles with different composition by cation exchange. PMID:23470030

Li, Wenhua; Zamani, Reza; Ibáñez, Maria; Cadavid, Doris; Shavel, Alexey; Morante, Joan Ramon; Arbiol, Jordi; Cabot, Andreu

2013-03-27

9

Surface-initiated atom transfer radical polymerization-induced transformation of selenium nanowires into copper selenide@polystyrene core-shell nanowires.  

PubMed

This Article reports the first preparation of cuprous and cupric selenide nanowires coated with a ?5 nm thick sheath of polystyrene (copper selenide@polystyrene). These hybrid nanostructures are prepared by the transformation of selenium nanowires in a one-pot reaction, which is performed under ambient conditions. The composition, purity, and crystallinity of the copper selenide@polystyrene products were assessed by scanning transmission electron microscopy, electron energy-loss spectroscopy, X-ray powder diffraction, and X-ray photoelectron spectroscopy techniques. We determined that the single crystalline selenium nanowires are converted into polycrystalline copper selenide@polystyrene nanowires containing both cuprous selenide and cupric selenide. The product is purified through the selective removal of residual, non-transformed selenium nanowires by performing thermal evaporation below the decomposition temperature of these copper selenides. Powder X-ray diffraction of the purified copper selenide nanowires@polystyrene identified the presence of hexagonal, cubic, and orthorhombic phases of copper selenide. These purified cuprous and cupric selenide@polystyrene nanowires have an indirect bandgap of 1.44 eV, as determined by UV-vis absorption spectroscopy. This new synthesis of polymer-encapsulated nanoscale materials may provide a method for preparing other complex hybrid nanostructures. PMID:24041404

Wang, Michael C P; Gates, Byron D

2013-10-01

10

Simultaneous phase and morphology controllable synthesis of copper selenide films by microwave-assisted nonaqueous approach  

NASA Astrophysics Data System (ADS)

Copper selenide films with different phase and morphology were synthesized on copper substrate through controlling reaction solvent by microwave-assisted nonaqueous approach. The films were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The result showed that the pure films could be obtained using cyclohexyl alcohol or benzyl alcohol as solvent. The cubic Cu2-xSe dendrites were synthesized in cyclohexyl alcohol reaction system and hexagonal CuSe flaky crystals were obtained with benzyl alcohol as solvent.

Li, Jing; Fa, Wenjun; Li, Yasi; Zhao, Hongxiao; Gao, Yuanhao; Zheng, Zhi

2013-02-01

11

Charge-carrier transport mechanism in copper indium di-selenide thin films  

NASA Astrophysics Data System (ADS)

Thin films of copper indium di-selenide have been grown onto glass substrates by a stacked elemental layer (SEL) deposition technique in vacuum. The elemental composition of the films was ascertained by proton-induced x-ray emission (PIXE) spectroscopy. The electrical dc conductivity and the Hall coefficient of the films have been measured in the temperature range of -130 to +127 °C. The mode of transport of the charge carriers has been analysed. It is found that a multiple scattering effect is operative in the transport process.

Firoz Hasan, S. M.; Subhan, M. A.; Mannan, Kh M.

1999-06-01

12

Phosphine-free synthesis of p-type copper(I) selenide nanocrystals in hot coordinating solvents.  

PubMed

We report a phosphine-free synthesis of p-type copper(I) selenide nanocrystals by a colloidal approach in a mixture of oleylamine and 1-octadecene. The nanocrystals had a cuboctahedral shape and cubic berzelianite phase. Films of these nonstoichiometric copper-deficient Cu(2-x)Se nanocrystals were highly conductive and showed high absorption coefficient in the near-infrared region. These nanocrystals could be used as hole-injection layers in optoelectronic devices. PMID:20540521

Deka, Sasanka; Genovese, Alessandro; Zhang, Yang; Miszta, Karol; Bertoni, Giovanni; Krahne, Roman; Giannini, Cinzia; Manna, Liberato

2010-07-01

13

Specific features of photoluminescence properties of copper-doped cadmium selenide quantum dots  

SciTech Connect

The effect of doping with copper on the photoluminescence properties of cadmium selenide quantum dots 4 nm in dimension is studied. The quenching of the excitonic photoluminescence band related to the quantum dots and the appearance of an impurity photoluminescence band in the near-infrared region are observed after doping of the quantum dots with copper. It is established that, on doping of the quantum dots, the photoluminescence kinetics undergoes substantial changes. The photoluminescence kinetics of the undoped quantum dots is adequately described by a sum of exponential relaxation relations, whereas the photoluminescence kinetics experimentally observed in the region of the impurity band of the copper-doped samples follows stretched exponential decay, with the average lifetimes 0.3-0.6 {mu}s at the photon energies in the range of 1.47-1.82 eV. The experimentally observed changes in the photoluminescence properties are attributed to transformation of radiative centers in the quantum dots when doped with copper atoms.

Tselikov, G. I., E-mail: gleb@vega.phys.msu.ru [Moscow State University, Faculty of Physics (Russian Federation); Dorofeev, S. G.; Tananaev, P. N. [Moscow State University, Faculty of Chemistry (Russian Federation); Timoshenko, V. Yu. [Moscow State University, Faculty of Physics (Russian Federation)

2011-09-15

14

Copper Selenide Nanosnakes: Bovine Serum Albumin-Assisted Room Temperature Controllable Synthesis and Characterization  

PubMed Central

Herein we firstly reported a simple, environment-friendly, controllable synthetic method of CuSe nanosnakes at room temperature using copper salts and sodium selenosulfate as the reactants, and bovine serum albumin (BSA) as foaming agent. As the amounts of selenide ions (Se2?) released from Na2SeSO3 in the solution increased, the cubic and snake-like CuSe nanostructures were formed gradually, the cubic nanostructures were captured by the CuSe nanosnakes, the CuSe nanosnakes grew wider and longer as the reaction time increased. Finally, the cubic CuSe nanostructures were completely replaced by BSA–CuSe nanosnakes. The prepared BSA–CuSe nanosnakes exhibited enhanced biocompatibility than the CuSe nanocrystals, which highly suggest that as-prepared BSA–CuSe nanosnakes have great potentials in applications such as biomedical engineering.

2010-01-01

15

Hydrothermal synthesis of copper selenides with controllable phases and morphologies from an ionic liquid precursor  

NASA Astrophysics Data System (ADS)

Cu2-xSe nanocrystals and CuSe nanoflakes are successfully synthesized through a convenient hydrothermal method from an ionic liquid precursor 1-n-butyl-3-ethylimidazolium methylselenite ([BMIm][SeO2(OCH3)]). The phases and morphologies of the copper selenides can be controlled by simply changing the atom ratio of Cu/Se in the reactants and reaction temperature. Furthermore, it is found that the [BMIm][SeO2(OCH3)] not only serves as Se source but also has influence on the shapes of CuSe nanoflakes. The adsorption of alkyl imidazolium rings ([BMIm]+) onto the (0001) facets of covellite CuSe prohibits the growth in the [0001] direction, and CuSe nuclei growth mainly processes along the six symmetric directions (+/-[01&cmb.macr;11], +/-[101&cmb.macr;1&cmb.macr;], and +/-[1&cmb.macr;100]) to form flakelike CuSe. The obtained copper selenides are characterized by XRD, SEM, EDS, XPS, TEM, and HRTEM. The results indicate that the Cu2-xSe nanocrystals are nearly spherical particles with an average diameter of about 20 nm, the hexagonal CuSe nanoflakes are single crystals with an edge length of 100-400 nm and a thickness of 25-50 nm. The potential formation mechanism of the copper selenides is also proposed.Cu2-xSe nanocrystals and CuSe nanoflakes are successfully synthesized through a convenient hydrothermal method from an ionic liquid precursor 1-n-butyl-3-ethylimidazolium methylselenite ([BMIm][SeO2(OCH3)]). The phases and morphologies of the copper selenides can be controlled by simply changing the atom ratio of Cu/Se in the reactants and reaction temperature. Furthermore, it is found that the [BMIm][SeO2(OCH3)] not only serves as Se source but also has influence on the shapes of CuSe nanoflakes. The adsorption of alkyl imidazolium rings ([BMIm]+) onto the (0001) facets of covellite CuSe prohibits the growth in the [0001] direction, and CuSe nuclei growth mainly processes along the six symmetric directions (+/-[01&cmb.macr;11], +/-[101&cmb.macr;1&cmb.macr;], and +/-[1&cmb.macr;100]) to form flakelike CuSe. The obtained copper selenides are characterized by XRD, SEM, EDS, XPS, TEM, and HRTEM. The results indicate that the Cu2-xSe nanocrystals are nearly spherical particles with an average diameter of about 20 nm, the hexagonal CuSe nanoflakes are single crystals with an edge length of 100-400 nm and a thickness of 25-50 nm. The potential formation mechanism of the copper selenides is also proposed. Electronic supplementary information (ESI) available: Fig. S1: 1-n-butyl-3-methylimidazolium methylselenite ([BMIm][SeO2(OCH3)]. Fig. S2: XRD pattern of Se from [BMIm][SeO2(OCH3)]. Fig. S3: Survey XPS spectra of (a) Cu2-xSe and (b) CuSe. Fig. S4: Schematic illustration of the chemical bonds in [BMIm][SeOB2B(OCHB3B)]. Fig. S5: (a) XRD pattern and (b) SEM image of CuB2-xBSe from the NaB2BSeOB3B precursor without using [BMIm]Br, (c) SEM image of CuB2-xBSe from the NaB2BSeOB3B precursor and equal mole amount of [BMIm]Br (XRD pattern is not listed). Fig. S6: (a) SEM image of sample 2 synthesized under the mole ratio of Cu/Se = 1 and reaction temperature 150 °C (b) XRD pattern of sample 1 synthesized under the mole ratio of Cu/Se = 2 and reaction temperature 120 °C (c) XRD patterns of samples synthesized under the mole ratio of Cu/Se = 2 and reaction temperature 150 °C (sample 1, a) and 120 °C (sample 4, b); (d) XRD pattern of sample 6 synthesized under the mole ratio of Cu/Se = 1 : 2 and reaction temperature 180 °C (e) SEM pattern of sample 6, inset (a) is the magnified SEM image of a Cu2-xSe microcrystal, inset (b) is the corresponding cogeometrical structure of Cu2-xSe microcrystal; (f) SEM image of sample 7 synthesized under the mole ratio of Cu/Se = 2 : 1 and reaction temperature 180 °C. Fig. S7: SEM images of sample 6 synthesized at 180 °C for different reaction times of (a) 4 h, (b) 8 h. See DOI: 10.1039/c1nr10833f

Liu, Xiaodi; Duan, Xiaochuan; Peng, Peng; Zheng, Wenjun

2011-12-01

16

The optical and electrical properties of copper indium di-selenide thin films  

NASA Astrophysics Data System (ADS)

Thin films of copper indium di-selenide (CIS) with a wide range of compositions near stoichiometry have been formed on glass substrates in vacuum by the stacked elemental layer (SEL) deposition technique. The compositional and optical properties of the films have been measured by proton-induced X-ray emission (PIXE) and spectrophotometry (photon wavelength range of 300-2500 nm), respectively. Electrical conductivity ( ?), charge-carrier concentration ( n), and Hall mobility ( ?H) were measured at temperatures ranging from 143 to 400 K. It was found that more indium-rich films have higher energy gaps than less indium-rich ones while more Cu-rich films have lower energy gaps than less Cu-rich films. The sub-bandgap absorption of photons is minimum in the samples having Cu/In ? 1 and it again decreases, as Cu/In ratio becomes less than 0.60. Indium-rich films show n-type conductivities while near-stoichiometric and copper-rich films have p-type conductivities. At 300 K ?, n and ?H of the films vary from 2.15 × 10 -3 to 1.60 × 10 -1 (? cm) -1, 2.28 × 10 15 to 5.74 × 10 17 cm -3 and 1.74 to 5.88 cm 2 (V s) -1, respectively, and are dependent on the composition of the films. All the films were found to be non-degenerate. The ionization energies for acceptors and donors vary between 12 and 24, and 3 and 8 meV, respectively, and they are correlated well with the Cu/In ratios. The crystallites of the films were found to be partially depleted in charge carriers.

Firoz Hasan, S. M.; Subhan, M. A.; Mannan, Kh. M.

2000-08-01

17

The Modification of Polyamide Tapes by the Conducting Copper Sulfide-Copper Selenide Layers  

Microsoft Academic Search

duration of treatment. The SeS4O6 2- anions diffused into polyamide gradually decompose and the decomposition products - sulfate ions and SO2 - are washed out from a polymer but elemental selenium remains in it. Therefore, the colour of polyamide tapes depending on a degree of SeS4O6 2- ions decomposition changes from colourless to yellow, brown or red. The copper sulfide

Vitalijus JANICKIS; Remigijus IVANAUSKAS

18

Template free-solvothermaly synthesized copper selenide (CuSe, Cu 2? x Se, ?-Cu 2Se and Cu 2Se) hexagonal nanoplates from different precursors at low temperature  

Microsoft Academic Search

Nonstoichiometric (Cu2?xSe) and stoichiometric (CuSe, ?-Cu2Se and Cu2Se) copper selenide hexagonal nanoplates have been synthesized using different general and convenient copper sources, e.g. copper chloride, copper sulphate, copper nitrate, copper acetate, elemental copper with elemental selenium, friendly ethylene glycol and hydrazine hydrate in a defined amount of water at 100°C within 12h adopting the solvothermal method. Phase analysis, purity and

Pushpendra Kumar; Kedar Singh; O. N. Srivastava

2010-01-01

19

Nanocrystalline dye-sensitized solar cell\\/copper indium gallium selenide thin-film tandem showing greater than 15% conversion efficiency  

Microsoft Academic Search

Multijunction stacked (tandem) solar cells can increase the overall photovoltaic conversion efficiency by optimal utilization of the solar spectrum in individual cells. We demonstrate that a photovoltaic tandem cell comprising a nanocrystalline dye-sensitized solar cell as a top cell for high-energy photons and a copper indium gallium selenide thin-film bottom cell for lower-energy photons produces AM 1.5 solar to electric

P. Liska; K. R. Thampi; M. Grätzel; D. Brémaud; D. Rudmann; H. M. Upadhyaya; A. N. Tiwari

2006-01-01

20

Three approaches to economical photovoltaics: Conformal copper sulfide , organic luminescent films, and lead selenide nanocrystal superlattices  

NASA Astrophysics Data System (ADS)

Three routes to more efficient photovoltaics using conformal Cu2S, organic luminescent films, and nanocrystalline PbSe films are outlined below. Properties of these materials are investigated experimentally and numerically in separate studies. In the first study, chemical vapor deposition (CVD) processes were used to fabricate Cu2S using hydrogen sulfide and the metal-organic precursor, KI5. The alternating exposure of mesoporous TiO2 and planar ZnO to the two precursors resulted in films that penetrated porous structures and deposited at a constant rate of 0.08nm/cycle over the temperature range 150C-400°C. Sheet resistance and optical absorption measurements suggest the presence of a metallic copper-poor phase of less than 100nm thick forming at the Cu2S/substrate boundary. In a separate study, organic films doped with luminescent dyes were placed above CdTe/CdS solar cells to convert high energy photons to lower energies, better matched to the CdTe/CdS quantum efficiency peak. Efficiency improvements of up to 8.5% were obtained after optimizing dye concentration, dye chemistry, and the host material. Long-term stability tests show that the organic films are stable for at least 5000 hours under 1 sun illumination provided that the dye is encapsulated in an oxygen and water free environment. Finally, a Monte Carlo model was developed to simulate electron and hole transport in nanocrystalline PbSe films. Transport is carried out as a series of thermally activated tunneling events between neighboring sites on a cubic lattice. Each site, representing an individual nanocrystal, is assigned a size-dependent electronic structure, and the effects of crystal size, charging, inter-crystal coupling, and energetic disorder on electron and hole mobilities/conductivities are investigated. Results of simulated field effect measurements confirm that electron mobilities and conductivities increase by an order of magnitude when the average nanocrystal diameter is increased in the 3-5nm range. Electron mobilities/conductivities begin to decrease for average nanocrystal diameters above 6nm. Our model suggests that as crystal size increases, fewer hops are required to traverse a given film length and that site energy disorder significantly inhibits transport in films composed of smaller nanocrystals. The dip in transport above 6nm can be explained by a decrease in tunneling amplitudes and by carrier interactions, which become more frequent at larger crystal diameters. Using a nearly identical set of parameter values as the electron simulations, hole simulations confirm experimental mobilities, which increase with nanocrystal size over two orders of magnitude.

Carbone, Ian A.

21

A study on the optics of copper indium gallium (di)selenide (CIGS) solar cells with ultra-thin absorber layers.  

PubMed

We present a systematic study of the effect of variation of the zinc oxide (ZnO) and copper indium gallium (di)selenide (CIGS) layer thickness on the absorption characteristics of CIGS solar cells using a simulation program based on finite element method (FEM). We show that the absorption in the CIGS layer does not decrease monotonically with its layer thickness due to interference effects. Ergo, high precision is required in the CIGS production process, especially when using ultra-thin absorber layers, to accurately realize the required thickness of the ZnO, cadmium sulfide (CdS) and CIGS layer. We show that patterning the ZnO window layer can strongly suppress these interference effects allowing a higher tolerance in the production process. PMID:24922252

Xu, Man; Wachters, Arthur J H; van Deelen, Joop; Mourad, Maurice C D; Buskens, Pascal J P

2014-03-10

22

Template free-solvothermaly synthesized copper selenide (CuSe, Cu 2- xSe, ?-Cu 2Se and Cu 2Se) hexagonal nanoplates from different precursors at low temperature  

NASA Astrophysics Data System (ADS)

Nonstoichiometric (Cu 2- xSe) and stoichiometric (CuSe, ?-Cu 2Se and Cu 2Se) copper selenide hexagonal nanoplates have been synthesized using different general and convenient copper sources, e.g. copper chloride, copper sulphate, copper nitrate, copper acetate, elemental copper with elemental selenium, friendly ethylene glycol and hydrazine hydrate in a defined amount of water at 100 °C within 12 h adopting the solvothermal method. Phase analysis, purity and morphology of the product have been well studied by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray diffraction (EDAX) techniques. The structural and compositional analysis revealed that the products were of pure phase with corresponding atomic ratios. SEM, TEM and HRTEM analyses revealed that the nanoplates were in the range 200-450 nm and the as-prepared products were uniform and highly crystallized. The nanoplates consisted of {0 0 1} facets of top-bottom surfaces and {1 1 0} facets of the other six side surfaces. This new approach encompasses many advantages over the conventional solvothermal method in terms of product quality (better morphology control with high yield) and reaction conditions (lower temperatures). Copper selenide hexagonal nanoplates obtained by the described method could be potential building blocks to construct functional devices and solar cell. This work may open up a new rationale on designing the solution synthesis of nanostructures for materials possessing similar intrinsic crystal symmetry. On the basis of the carefully controlled experiments mentioned herein, a plausible formation mechanism of the hexagonal nanoplates was suggested and discussed. To the best of our knowledge, this is the first report on nonstoichiometric (Cu 2- xSe) as well as stoichiometric (CuSe, ?-Cu 2Se and Cu 2Se) copper selenide hexagonal nanoplates with such full control of morphologies and phases by this method under mild conditions.

Kumar, Pushpendra; Singh, Kedar; Srivastava, O. N.

2010-09-01

23

Removal of hydrogen selenide  

SciTech Connect

This patent describes a process for removal of hydrogen selenide from a liquid stream which comprises treating a stream of solvent selected from the group consisting of (tertiary) amines, aminoalcohols, glycols, glycol ethers, sulfones, sulfoxides, N-heterocyclics, amides or mixtures thereof, with a heavy metal non-selenide salt to precipitate the hydrogen selenide as a heavy metal selenide. A process for the purification of a gas stream containing hydrogen selenide and acidic gases which comprises (1) contacting the gas stream with an aqueous scrubbing solution to remove at least a part of the hydrogen selenide; (2) contacting the scrubbing solution with a heavy metal non-selenide salt to precipitate hydrogen selenide as a heavy metal selenide salt; and (3) treating the gas stream from (1) with a liquid solvent for the absorption of acidic gases.

Baker, D.C.

1988-12-13

24

Magnetometer uses bismuth-selenide  

NASA Technical Reports Server (NTRS)

Characteristics of bismuth-selenide magnetometer are described. Advantages of bismuth-selenide magnetometer over standard magnetometers are stressed. Thermal stability of bismuth-selenide magnetometer is analyzed. Linearity of output versus magnetic field over wide range of temperatures is reported.

Woollman, J. A.; Spain, I. L.; Beale, H.

1972-01-01

25

Development of the data base for a degradation model of a selenide RTG. [Radioisotope Thermoelectric Generator  

NASA Technical Reports Server (NTRS)

The paper is concerned with the evaluation of the materials used in a selenide radioisotope thermoelectric generator (RTG). These materials are composed of n-type gadolinium selenide and n-type copper selenide. A three-fold evaluation approach is being used: (1) the study of the rate of change of the thermal conductivity of the material, (2) the investigation of the long-term stability of the material's Seebeck voltage and electrical resistivity under current and temperature gradient conditions, and (3) determination of the physical behavior and compatibility of the material with surrounding insulation at elevated temperatures. Programmatically, the third category of characteristic evaluation is being emphasized.

Stapfer, G.; Truscello, V. C.

1977-01-01

26

[Aqua-bis-(nitrato-?O)copper(II)]-?-{bis-[5-methyl-3-(pyridin-2-yl)-1H-pyrazol-4-yl]selenide}-[diaqua-(nitrato-?O)copper(II)] nitrate monohydrate  

PubMed Central

In the title binuclear complex, [Cu2(NO3)3(C18H16N6Se)(H2O)3]NO3·H2O, the CuII ions are penta­coordinated in a tetra­gonal–pyramidal geometry. In both cases, the equatorial planes are formed by a chelating pyrazole-pyridine group, a water mol­ecule and a nitrate O atom, whereas the apical positions are occupied by a water mol­ecule for one CuII ion and a nitrate O atom for the other. The organic selenide ligand adopts a trans configuration with respect to the C–Se–C plane. Numerous inter­molecular O—H?O and N—H?O hydrogen bonds between the coordinating and lattice water mol­ecules, nitrate anions and pyrazole groups are observed. ?–? stacking inter­actions between the pyridine rings [averaged centroid–centroid distance = 3.652?(5)?Å] are also present. The lattice water molecule is equally disordered over two sets of sites.

Seredyuk, Maksym; Pavlenko, Vadim A.; Gumienna-Kontecka, Elzbieta; Iskenderov, Turganbay S.

2012-01-01

27

Doping in Zinc Selenide  

NASA Astrophysics Data System (ADS)

An experimental technique ensuring the incorporation of substitutional arsenic and copper doping in ZnSe is presented. Two techniques are investigated. In each, neutron transmutation doping is employed to introduce arsenic and copper dopants in ZnSe. In the first technique, as-grown crystals of ZnSe are exposed to thermal neutrons. The crystals are thermally annealed after irradiation in order to repair the neutron induced lattice damage. The thermal annealing schedules employed in this work, however, do not fully repair the ZnSe lattice. In the second technique, homoepitaxial layers of ZnSe are deposited with irradiated zinc and selenium as source materials. High quality layers of ZnSe, characterized by x-ray diffraction and low temperature photoluminescence, are produced. The long half lives of As^ {75} and Zn^{65} allow the epitaxial layers to be formed prior to nuclear decay. Since the nuclear recoil associated with the decays are not sufficient to displace the dopant nuclei from their substitutional lattice sites, the technique results in isolated As_{Se } or isolated Cu_{Zn } being introduced in layers of ZnSe after crystal growth. Since the dopants are introduced in the bulk crystal after crystal growth, the doping process is decoupled from any interactions present during crystal growth. A technique in which crystal doping is decoupled from crystal growth provides several unique probes for arsenic and copper doping in ZnSe.

Wheeler, Edward Dean

28

Low-Resistivity Zinc Selenide for Heterojunctions  

NASA Technical Reports Server (NTRS)

Magnetron reactive sputtering enables doping of this semiconductor. Proposed method of reactive sputtering combined with doping shows potential for yielding low-resistivity zinc selenide films. Zinc selenide attractive material for forming heterojunctions with other semiconductor compounds as zinc phosphide, cadmium telluride, and gallium arsenide. Semiconductor junctions promising for future optoelectronic devices, including solar cells and electroluminescent displays. Resistivities of zinc selenide layers deposited by evaporation or chemical vapor deposition too high to form practical heterojunctions.

Stirn, R. J.

1986-01-01

29

COPPER  

EPA Science Inventory

The report is a review of current knowledge of the distribution of copper in the environment and living things. Metabolism and the effects of copper in the biosphere are also considered. Copper compounds are common and widely distributed in nature. They are also extensively mined...

30

Synthesis and characterization of electrodeposited copper indium selenide and copper (indium, gallium) selenide thin films  

NASA Astrophysics Data System (ADS)

Electrodeposition is a cost effective method for growing polycrystalline thin films which is not limited by substrate/superstrate size and does not require the use of a vacuum. In this research, CuInSe2 and Cu(In,Ga)Se 2 polycrystalline thin films have been synthesized by electrodeposition. Both of these materials have very high absorption coefficients when compared to Si and GaAs, and can have their band gaps adjusted through the control of their stoichiometries. Both CuInSe2 and Cu(In,Ga)Se2 are direct band gap semiconductors with the chalcopyrite crystal structure. Therefore, these materials are important for use in high efficiency photovoltaic solar cells. In an attempt to understand how the composition, morphology and crystallinity depend on electrodeposition conditions, various thin films of CuInSe2 and Cu(In,Ga)Se2 were grown by electrodeposition. These films were then characterized by a number of characterization techniques which include (1) scanning electron microscopy, (2) scanning tunneling microscopy, (3) energy dispersive spectroscopy, (4) X-ray diffraction, and (5) Auger electron spectroscopy. Results based on this research indicate two main conclusions. (1) Modulated or layered films of CuInSe2 can be grown by electrodeposition. Measurements made by Scanning Tunneling Microscopy of cleaved cross sections of the CuInSe2 layered films indicate the successful formation of layers. (2) Cu(In,Ga)Se2 thin films can be electrodeposited by a two-step process with minimal post treatment steps. The process developed here can be done at room temperature. Two electrochemical baths are used, one to electrodeposit a CuGa2 binary alloy, followed by the electrodeposition of a CuInSe2 thin film from another bath. The resulting bilayer film is then annealed in flowing argon at an elevated temperature to form the CIGS compound. Characterization results from measurements made by X-ray diffraction show that the resulting films maintain the basic chalcopyrite structure while the Bragg peaks shift to larger diffraction angles with increasing gallium content in the film. This is evidence to support the successful formation of CIGS films. This data is further corroborated by the energy dispersive spectroscopy and Auger electron spectroscopy data.

Friedfeld, Robert Bonheur

31

The Bismuth Telluride-Bismuth Selenide System.  

National Technical Information Service (NTIS)

These data sheets present a compilation of a wide range of electronic properties for the bismuth telluride-bismuth selenide system. Electrical properties include conductivity, dielectric constant, Hall coefficient, and mobility. Emission data were broken ...

M. Neuberger

1966-01-01

32

Crystal chemistry and self-lubricating properties of monochalcogenides gallium selenide and tin selenide  

SciTech Connect

This paper describes the fundamentals of the crystal chemistry and self-lubricating mechanisms of two monochalcogenides; tin selenide and gallium selenide. Specifically, it enumerates their inter-atomic array and bond structure in crystalline states, and correlates this fundamental knowledge with their self-lubricating capacity. Friction tests assessing the self-lubricating performance of gallium and tin selenides were carried out on a pin-on-disk machine. Specifically, large crystalline pieces of gallium selenide and tin selenide were cut and cleaved into flat squares and subsequently rubbed against the sapphire balls. In another case, the fine powders (particle size {approx} 50--100 {mu}m) of gallium selenide and tin selenide were manually fed into the sliding interfaces of 440C pins and 440C disks. For the specific test conditions explored, it was found that the friction coefficients of the sapphire/gallium selenide and sapphire/tin selenide pairs were {approx} 0.23 and {approx} 0.35, respectively. The friction coefficients of 440C pin/440C disk test pairs with gallium selenide and tin selenide powders were on the orders of {approx} 0.22 and {approx} 0.38, respectively. For comparison, a number of parallel friction tests were performed with MoS{sub 2} powders and compacts and the results of these tests were also reported. The friction data together with the crystal-chemical knowledge and the electron microscopic evidence supported the conclusion that the lubricity and self-lubricating mechanisms of these solids are closely related to their crystal chemistry and the nature of interlayer bonding.

Erdemir, A.

1993-02-01

33

Al(2)O(3)-supported Cu-Catalyzed Electrophilic Substitution by PhSeBr in Organoboranes, Organosilanes, and Organostannanes. A protocol for the synthesis of unsymmetrical diaryl and alkyl aryl selenides.  

PubMed

Alumina-supported copper sulfate efficiently catalyzes electrophilic substitution in organoborane, organosilanes, and organostannanes by phenylselenium bromide providing a novel and efficient route to the synthesis of unsymmetrical diaryl and alkyl aryl selenides. A series of aryl, alkyl, and heteroaryl phenyl selenides were obtained in high yields. The catalyst is inexpensive, eco- and user-friendly, and recyclable. The mechanism involving Cu-assisted nucleophilic displacement of Br in PhSeBr by mild nucleophiles is described. PMID:20560558

Bhadra, Sukalyan; Saha, Amit; Ranu, Brindaban C

2010-07-16

34

Copper-catalyzed C-H bond direct chalcogenation of aromatic compounds leading to diaryl sulfides, selenides, and diselenides by using elemental sulfur and selenium as chalcogen sources under oxidative conditions.  

PubMed

The reactions of aromatic compounds and elemental chalcogens catalyzed by a copper salt with molecular oxygen as an oxidant were carried out. The reaction of 3-substituted imidazo[1,5-a]pyridines and elemental sulfur in the presence of CuTC (copper(I) thiophenecarboxylate) gave the corresponding bisimidazopyridyl sulfides in good to quantitative yields. The reaction proceeded even under aerobic oxidation conditions. The use of a polar solvent was crucial for the reaction, and DMSO (dimethyl sulfoxide) in particular stimulated the reaction. The reaction could be applied to common aromatic compounds, such as N-methyl indole and dialkyl anilines. The reaction of indole proceeded at the nucleophilic C3 position rather than at the acidic C2 position. In addition, the reaction of dialkyl anilines proceeded with an ortho, para orientation. The reactions of imidazopyridines and elemental selenium under similar conditions gave the corresponding bisimidazopyridyl diselenides along with bisimidazopyridyl monoselenides. The resulting diselenides were readily converted to the corresponding monoselenides with unreacted imidazopyridines under the same conditions. The reaction could be applied to the copolymerization of bifunctional bisimidazopyridines and elemental sulfur to give oligomeric copolymers in quantitative yield. PMID:24347073

Shibahara, Fumitoshi; Kanai, Takafumi; Yamaguchi, Eiji; Kamei, Akika; Yamauchi, Takayuki; Murai, Toshiaki

2014-01-01

35

Study of filamentation threshold in zinc selenide.  

PubMed

The possibility of creating filaments with laser wavelengths ranging from 800 nm to 2.4 µm was investigated using an OPA laser system. Zinc Selenide's (ZnSe) unique characteristics - small band gap E(gZnSe)=2.67eV and positive dispersion for this wavelength range - are well suited for filamentation study where multi-photon absorption can be achieved with two to six photons. PMID:24663922

Durand, Magali; Houard, Aurélien; Lim, Khan; Durécu, Anne; Vasseur, Olivier; Richardson, Martin

2014-03-10

36

Growth of cadmium selenide layers by electrodeposition  

Microsoft Academic Search

Cadmium selenide (CdSe) films have been electrodeposited from a bath containing CdSO4 and SeO2. The pH of the bath was around 2. The deposition was done by short circuiting different substrates like Indium Tin Oxide (ITO), molybdenum, sodium selenosulphite etc. to an easily oxidizable electrode (such as Al\\/Cd) in an electrolytic bath. The temperature of the deposition bath was varied

K. R. Murali; I. Radhakrishna; K. Nagaraja Rao; V. K. Venkatesan

1990-01-01

37

Growth of cadmium selenide layers by electrodeposition  

Microsoft Academic Search

Cadmium selenide (CdSe) films have been electrodeposited from a bath containing CdSO4 and SeO2. The pH of the bath was around 2. The deposition was done by short circuiting different substrates like Indium Tin Oxide ITO, molybdenum, sodium selenosulphite etc. to an easily oxidizable electrode (such as Al\\/Cd) in an electrolytic bath. The temperature of the deposition bath was varied

K. R. Murali; I. Radhakrishna; K. Nagaraja Rao; V. K. Venkatesan

1990-01-01

38

Interferences in electrochemical hydride generation of hydrogen selenide  

NASA Astrophysics Data System (ADS)

Interferences from Cu(II), Zn(II), Pt(IV), As(III) and nitrate on electrochemical hydride generation of hydrogen selenide were studied using a tubular flow-through generator, flow injection sample introduction and quartz tube atomic absorption spectrometry. Comparison with conventional chemical generation using tetrahydroborate was also performed. Lead and reticulated vitreous carbon (RVC), both in particulate form, were used as cathode materials. Signal supressions up to 60-75%, depending on the cathode material, were obtained in the presence of up to 200 mg l-1 of nitrate due to the competitive reduction of the anion. Interference from As(III) was similar in electrochemical and chemical generation, being related to the quartz tube atomization process. Zinc did not interfere up to Se/Zn ratios 1:100, whereas copper and platinum showed suppression levels up to 50% for Se/interferent ratios 1:100. Total signal suppression was observed in presence of Se/Cu ratios 1:100 when RVC cathodes were used. No memory effects were observed in any case. Scanning electron microscopy and squared wave voltametry studies supported the interference mechanism based on the decomposition of the hydride on the dispersed particles of the reduced metal.

Bolea, E.; Laborda, F.; Belarra, M. A.; Castillo, J. R.

2001-12-01

39

Synthesis and characterization of luminescent cadmium selenide/zinc selenide/zinc sulfide cholinomimetic quantum dots  

NASA Astrophysics Data System (ADS)

Luminescent quantum dots conjugated with highly selective molecular recognition ligands are widely used for targeting and imaging biological structures. In this paper, water soluble cholinomimetic cadmium selenide (core), zinc selenide/zinc sulfide (shell) quantum dots were synthesized for targeting cholinergic sites. Cholinomimetic specificity was incorporated by conjugation of the quantum dots to an aminated analogue of hemicholinium-15, a well known competitive inhibitor of the high affinity choline uptake transporter. Detailed evaluation of the nanocrystal synthesis and characterization of the final product was conducted by 1H and 31P NMR, absorption and emission spectroscopy, as well as transmission electron microscopy.Luminescent quantum dots conjugated with highly selective molecular recognition ligands are widely used for targeting and imaging biological structures. In this paper, water soluble cholinomimetic cadmium selenide (core), zinc selenide/zinc sulfide (shell) quantum dots were synthesized for targeting cholinergic sites. Cholinomimetic specificity was incorporated by conjugation of the quantum dots to an aminated analogue of hemicholinium-15, a well known competitive inhibitor of the high affinity choline uptake transporter. Detailed evaluation of the nanocrystal synthesis and characterization of the final product was conducted by 1H and 31P NMR, absorption and emission spectroscopy, as well as transmission electron microscopy. Electronic supplementary information (ESI) available: NMR spectra supporting the synthesis of the HC-15 QDs are available. See DOI: 10.1039/c2nr30713h

Gégout, Claire; McAtee, Maria L.; Bennett, Nichole M.; Viranga Tillekeratne, L. M.; Kirchhoff, Jon R.

2012-07-01

40

Tellurium distribution in copper anode slimes smelting  

Microsoft Academic Search

Tellurium is a common minor constituent of copper anode slimes. The distribution of tellurium between the phases during slimes\\u000a smelting is an important consideration, both in terms of metal quality and the capture of the oxidized tellurium. In this\\u000a work, the oxidation by oxygen at 1100 C of a silver-copper selenide matte containing 2 pct tellurium has been examined. The

D. R. Swinbourne; G. G. Barbante; A. Sheeran

1998-01-01

41

Low cost copper indium gallium selenide by the FASST® process  

Microsoft Academic Search

Low cost manufacturing of Cu(In,Ga)Se2 (CIGS) films for high efficiency PV devices by the innovative Field-Assisted Simultaneous Synthesis and Transfer (FASST®) process is reported. The FASST® process is a two-stage reactive transfer printing method relying on chemical reaction between two separate precursor films to form CIGS, one deposited on the substrate and the other on a printing plate in the

B. Sang; F. Adurodija; M. Taylor; A. Lim; J. Taylor; Y. Chang; S. McWilliams; R. Oswald; B. J. Stanbery; M. van Hest; J. Nekuda; A. Miedaner; C. Curtis; J. Leisch; D. Ginley

2008-01-01

42

Analytical predictions of selenide RTG power degradation  

NASA Technical Reports Server (NTRS)

A mathematical model for the performance and degradation analysis of an RTG using the newly developed selenide thermoelectric materials has been developed at JPL. The computerized model is quite comprehensive and enables the accurate detailing of the electrical and thermal effects that take place within the thermocouple under any desired set of operation conditions, including heat input, ambient temperature and load conditions. The paper discusses the logic flow of the computer model and presents the time and temperature dependent results for various degradation mechanisms and rates as they have been established to date.

Noon, E. L.; Stapfer, G.; Raag, V.

1978-01-01

43

Preparation of iron selenide films by selenization technique  

Microsoft Academic Search

Iron selenide films have been grown by selenization of evaporated iron thin films. The substrates temperature during selenization was 573 or 723K. It is shown that whatever the substrate temperature is, for a partial pressure of Se of 3.75×10?2Pa, there is selenide compound formation. It is shown that the films are mainly composed of tetragonal FeSe while some crystallites of

N. Hamdadou; J. C. Bernède; A. Khelil

2002-01-01

44

Growth and characterization of electrosynthesized iron selenide thin films  

Microsoft Academic Search

Iron selenide (FeSe) thin films were electrodeposited onto indium doped tin oxide coated conducting glass (ITO) substrates at various bath temperatures from 30°C to 90°C in an aqueous electrolytic bath containing FeSO4 and SeO2. The deposition mechanism was investigated using cyclic voltammetry. The appropriate potential region where the formation of stoichiometric iron selenide thin films' occurs was found to be

S. Thanikaikarasan; T. Mahalingam; K. Sundaram; A. Kathalingam; Yong Deak Kim; Taekyu Kim

2009-01-01

45

The Diorganoselenium and Selenides Compounds Electrochemistry  

PubMed Central

The electrochemical behavior of Ar2SeCl2, and Ar2Se2, (Ar:CH3OC6H5; C2H5OC6H5) in acetonitrile (AN) containing tetrabutylammonium tetrafluoroborat (TBAFB) as supporting electrolyte was studied on a stationary electrode (spe). In order to elucidate the electrode reactions linear potential scan, cyclic voltammetry and controlled-potential coulometry were employed using a platinum electrode. It is shown that Ar2SeCl2 and Ar2Se2 are reduced and oxidized to Ar2Se, Ar2Se2Ar2, Se, and Ar2Se(BF4)2. It is generally accepted that as final electrochemical reduction products, the corresponding Ar2Se, Ar4Se2, and Se were formed. The disappearance of the diorganoselenium and selenide in the course of the coulometric experiments was validated by measuring the limiting current of the voltammetric waves at spe and UV spectrometry.

Tepecik, Abdulkadir; Altin, Zehra; Erturan, Seyfettin

2008-01-01

46

Growth of cadmium selenide layers by electrodeposition  

NASA Astrophysics Data System (ADS)

Cadmium selenide (CdSe) films have been electrodeposited from a bath containing CdSO4 and SeO2. The pH of the bath was around 2. The deposition was done by short circuiting different substrates like Indium Tin Oxide (ITO), molybdenum, sodium selenosulphite etc. to an easily oxidizable electrode (such as Al/Cd) in an electrolytic bath. The temperature of the deposition bath was varied in the range 60 to 85 C. The as-grown films were characterized by XRD and SEM. Electrical characterization of the ITO/-CdSe/In structure was made by studying the current-voltage characteristics. Optical absorption measurements yielded a direct band gap around 1.65 eV.

Murali, K. R.; Radhakrishna, I.; Nagaraja Rao, K.; Venkatesan, V. K.

1990-08-01

47

Control of accidental releases of hydrogen selenide in vented storage cabinets  

NASA Astrophysics Data System (ADS)

Highly toxic hydrogen selenide and hydrogen sulfide gases are used in the production of copper-indium-diselenide photovoltaic cells by reactive sputtering. In the event of an accident, these gases may be released to the atmosphere and pose hazards to public and occupational safety and health. This paper outlines an approach for designing systems for the control of these releases given the uncertainty in release conditions and lack of data on the chemical systems involved. Accidental releases of these gases in storage cabinets can be controlled by either a venturi and packed-bed scrubber and carbon adsorption bed, or containment scrubbing equipment followed by carbon adsorption. These systems can effectively reduce toxic gas emissions to levels needed to protect public health. The costs of these controls (~$0.012/Wp) are samll in comparison with current (~$6/Wp) and projected (~$I/Wp) production costs.

Fthenakis, V. M.; Moskowitz, P. D.; Sproull, R. D.

1988-07-01

48

Ex situ formation of metal selenide quantum dots using bacterially derived selenide precursors  

NASA Astrophysics Data System (ADS)

Luminescent quantum dots were synthesized using bacterially derived selenide (SeII-) as the precursor. Biogenic SeII- was produced by the reduction of SeIV by Veillonella atypica and compared directly against borohydride-reduced SeIV for the production of glutathione-stabilized CdSe and ?-mercaptoethanol-stabilized ZnSe nanoparticles by aqueous synthesis. Biological SeII- formed smaller, narrower size distributed QDs under the same conditions. The growth kinetics of biologically sourced CdSe phases were slower. The proteins isolated from filter sterilized biogenic SeII- included a methylmalonyl-CoA decarboxylase previously characterized in the closely related Veillonella parvula. XAS analysis of the glutathione-capped CdSe at the S K-edge suggested that sulfur from the glutathione was structurally incorporated within the CdSe. A novel synchrotron based XAS technique was also developed to follow the nucleation of biological and inorganic selenide phases, and showed that biogenic SeII- is more stable and more resistant to beam-induced oxidative damage than its inorganic counterpart. The bacterial production of quantum dot precursors offers an alternative, ‘green’ synthesis technique that negates the requirement of expensive, toxic chemicals and suggests a possible link to the exploitation of selenium contaminated waste streams.

Fellowes, J. W.; Pattrick, R. A. D.; Lloyd, J. R.; Charnock, J. M.; Coker, V. S.; Mosselmans, J. F. W.; Weng, T.-C.; Pearce, C. I.

2013-04-01

49

Ex Situ Formation of Metal Selenide Quantum Dots Using Bacterially Derived Selenide Precursors  

SciTech Connect

Luminescent quantum dots were synthesized using bacterially derived selenide (SeII-) as the precursor. Biogenic SeII- was produced by the reduction of Se-IV by Veillonella atypica and compared directly against borohydride-reduced Se-IV for the production of glutathione-stabilized CdSe and beta-mercaptoethanol-stabilized ZnSe nanoparticles by aqueous synthesis. Biological SeII- formed smaller, narrower size distributed QDs under the same conditions. The growth kinetics of biologically sourced CdSe phases were slower. The proteins isolated from filter sterilized biogenic SeII- included a methylmalonyl-CoA decarboxylase previously characterized in the closely related Veillonella parvula. XAS analysis of the glutathione-capped CdSe at the S K-edge suggested that sulfur from the glutathione was structurally incorporated within the CdSe. A novel synchrotron based XAS technique was also developed to follow the nucleation of biological and inorganic selenide phases, and showed that biogenic SeII- is more stable and more resistant to beam-induced oxidative damage than its inorganic counterpart. The bacterial production of quantum dot precursors offers an alternative, 'green' synthesis technique that negates the requirement of expensive, toxic chemicals and suggests a possible link to the exploitation of selenium contaminated waste streams.

Fellowes, Jonathan W.; Pattrick, Richard; Lloyd, Jon; Charnock, John M.; Coker, Victoria S.; Mosselmans, JFW; Weng, Tsu-Chien; Pearce, Carolyn I.

2013-04-12

50

Amphoteric properties of gold in zinc selenide  

NASA Astrophysics Data System (ADS)

Hall effect, electric conductivity, and charge carriers mobility in n-ZnSe single crystals doped with gold during the process of a long-term high-temperature annealing in Zn+Au melt with various Au contents were investigated in the temperature range from 77 to 300 K. It has been established that, at low gold concentration, Au atoms form mainly donor-type interstitial Au i defects. The increase of Au concentration in Zn+Au melt leads to the formation of both simple Au Zn defects and associative acceptors (Au Zn-Au i), (Au Zn-D Zn), and (Au Zn-V Se). These defects determine electrical properties of the crystals and they are responsible for the complex structure of excitonic and impurity radiation spectra. The influence of dopant concentration on both electrical and luminescent properties of n-ZnSe:Zn:Au crystals is investigated. The observed variations of electrical and luminescent properties are due to amphoteric properties of gold impurity in zinc selenide.

Avdonin, A. N.; Ivanova, G. N.; Nedeoglo, D. D.; Nedeoglo, N. D.; Sirkeli, V. P.

2005-08-01

51

Characterization of Zinc Selenide-Based Ultraviolet Detectors.  

National Technical Information Service (NTIS)

Wide bandgap semiconductors such as Zinc Selenide (ZnSe) have become popular for ultraviolet (UV) photodetectors. ZnSe has a higher photosensitivity compared to silicon-based detectors due to its larger bandgap. Its capability of turning optical power int...

J. V. Naval

2009-01-01

52

A single element light amplifier using sintered cadium selenide  

Microsoft Academic Search

The use of photoconductive sintered cadium selenide as the control element in a light amplifier offers the possibility of improved gain and speed of response. Such a single element light amplifier has been made and tested. The results show that moderate gains with high output luminance are possible with speeds in the range of moving pictures. Very high gains are

F. H. Nicoll

1959-01-01

53

Electron beam assisted synthesis of cadmium selenide nanomaterials  

SciTech Connect

Cadmium selenide nanomaterials of various shapes and sizes have been synthesized in different condensed media through electron beam irradiation using a 7 MeV linear accelerator. The microstructures in different media as well as the presence of capping reagents play a crucial role in the formation of nanomaterials of different shapes and sizes. Their optical properties could be efficiently tuned by controlling the synthetic parameters.

Rath, M. C.; Guleria, A.; Singh, S.; Singh, A. K.; Adhikari, S.; Sarkar, S. K. [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

2013-02-05

54

Chemical bath deposition of tin selenide thin films  

Microsoft Academic Search

Tin selenide thin films have been deposited on indium tin oxide glass slides in alkaline medium. The method is based on simple bath deposition technique that requires less chemicals and monitoring. Uniform and well-adhered films were obtained upon required deposition period. X-ray, morphology, optical and photoelectrochemical study was carried out for the as-deposited film. The films were polycrystalline and covered

Z Zainal; N Saravanan; K Anuar; M. Z Hussein; W. M. M Yunus

2004-01-01

55

Analysis of rare earth sulfides, selenides and tellurides.  

PubMed

The rare earth content of sulfides, selenides and tellurides is determined by titration with EDTA using Xylenol Orange as indicator. Sulfur is measured by titration of sulfate with lead nitrate solution after removal of rare earths on a cation exchanger. Selenium metal is precipitated from hydrochloric-sulfurous acid solution. Metallic tellurium is deposited from strongly acidic solutions containing sulfurous acid and hydrazine sulfate. An evaluation of the accuracy and precision of these methods is made. PMID:18959875

Kriege, O H; Theodore, M L

1966-02-01

56

Electron scattering mechanisms in n-type indium selenide  

Microsoft Academic Search

Electron scattering mechanisms in n-type indium selenide are investigated by means of the temperature dependence (4-500 K) of Hall mobility and the magnetic field dependence of Hall and magnetoresistance coefficients. The Schmid model for homopolar optical-phonon scattering can explain the temperature dependence of electron mobility above 40 K. The electron-phonon coupling constant is determined, g2=0.054. The optical phonon involved in

A. Segura; F. Pomer; A. Cantarero; W. Krause; A. Chevy

1984-01-01

57

Colloquium: The unexpected properties of alkali metal iron selenide superconductors  

NASA Astrophysics Data System (ADS)

The iron-based superconductors that contain FeAs layers as the fundamental building block in the crystal structures have been rationalized in the past using ideas based on the Fermi surface nesting of hole and electron pockets when in the presence of weak Hubbard U interactions. This approach seemed appropriate considering the small values of the magnetic moments in the parent compounds and the clear evidence based on photoemission experiments of the required electron and hole pockets. However, recent results in the context of alkali metal iron selenides, with generic chemical composition AxFe2-ySe2 (A=alkali metal element), have challenged those previous ideas since at particular compositions y the low-temperature ground states are insulating and display antiferromagnetic order with large iron magnetic moments. Moreover, angle-resolved photoemission studies have revealed the absence of hole pockets at the Fermi level in these materials. The present status of this exciting area of research, with the potential to alter conceptually our understanding of the iron-based superconductors, is here reviewed, covering both experimental and theoretical investigations. Other recent related developments are also briefly reviewed, such as the study of selenide two-leg ladders and the discovery of superconductivity in a single layer of FeSe. The conceptual issues considered established for the alkali metal iron selenides, as well as several issues that still require further work, are discussed.

Dagotto, Elbio

2013-04-01

58

The unexpected properties of alkali metal iron selenide superconductors  

SciTech Connect

The iron-based superconductors that contain FeAs layers as the fundamental building block in the crystal structures have been rationalized in the past using ideas based on the Fermi surface nesting of hole and electron pockets when in the presence of weak Hubbard U interactions. This approach seemed appropriate considering the small values of the magnetic moments in the parent compounds and the clear evidence based on photoemission experiments of the required electron and hole pockets. However, recent results in the context of alkali metal iron selenides, with generic chemical composition AxFe2ySe2 (A alkali metal element), have challenged those previous ideas since at particular compositions y the low-temperature ground states are insulating and display antiferromagnetic order with large iron magnetic moments. Moreover, angle-resolved photoemission studies have revealed the absence of hole pockets at the Fermi level in these materials. The present status of this exciting area of research, with the potential to alter conceptually our understanding of the ironbased superconductors, is here reviewed, covering both experimental and theoretical investigations. Other recent related developments are also briefly reviewed, such as the study of selenide two-leg ladders and the discovery of superconductivity in a single layer of FeSe. The conceptual issues considered established for the alkali metal iron selenides, as well as several issues that still require further work, are discussed.

Dagotto, Elbio R [ORNL

2013-01-01

59

Mass spectral study of substituted allyl aryl and allyl alkyl selenides and some analogous sulfides  

PubMed

The electron impact (EI) mass spectra of allyl aryl selenides showed abundant molecular ions and many fragment ions containing the selenium atom. alpha-Cleavage is the dominant process in the fragmentation of selenides, and cleavage product ions are characteristic of the substituents. In the case of 3-methyl allyl and related aryl selenides, characteristic delta-hydrogen migration to the selenium atom is observed. A McLafferty-type rearrangement is found in benzyl allyl selenides and substituted alkyl allyl selenides. The charge on the rearrangement products preferably remains on the fragments containing the phenyl group. The [M - SeH](+), [M - CH(3)](+) and [M - C(2)H(4)](+) ions are found only in the EI mass spectrum of allyl phenyl selenide, and are attributed to a Claisen rearrangement in the source of the mass spectrometer. All structurally informative fragmentation processes are supported by collision induced dissociation spectra of molecular ions. The fragmentation patterns found in methane chemical ionization (CI) spectra of the selenides were significantly different from those observed in EI. The EI and CI mass spectra of analogous sulfides showed similar behaviour to that observed in the corresponding selenides. Copyright 1999 John Wiley & Sons, Ltd. PMID:10421898

Prabhakar; Krishna; Kundu; Roy; Vairamani

1999-01-01

60

Sodium Selenide Toxicity Is Mediated by O2-Dependent DNA Breaks  

PubMed Central

Hydrogen selenide is a recurrent metabolite of selenium compounds. However, few experiments studied the direct link between this toxic agent and cell death. To address this question, we first screened a systematic collection of Saccharomyces cerevisiae haploid knockout strains for sensitivity to sodium selenide, a donor for hydrogen selenide (H2Se/HSe?/Se2?). Among the genes whose deletion caused hypresensitivity, homologous recombination and DNA damage checkpoint genes were over-represented, suggesting that DNA double-strand breaks are a dominant cause of hydrogen selenide toxicity. Consistent with this hypothesis, treatment of S. cerevisiae cells with sodium selenide triggered G2/M checkpoint activation and induced in vivo chromosome fragmentation. In vitro, sodium selenide directly induced DNA phosphodiester-bond breaks via an O2-dependent reaction. The reaction was inhibited by mannitol, a hydroxyl radical quencher, but not by superoxide dismutase or catalase, strongly suggesting the involvement of hydroxyl radicals and ruling out participations of superoxide anions or hydrogen peroxide. The •OH signature could indeed be detected by electron spin resonance upon exposure of a solution of sodium selenide to O2. Finally we showed that, in vivo, toxicity strictly depended on the presence of O2. Therefore, by combining genome-wide and biochemical approaches, we demonstrated that, in yeast cells, hydrogen selenide induces toxic DNA breaks through an O2-dependent radical-based mechanism.

Dauplais, Marc; Lazard, Myriam; Beuneu, Francois; Decourty, Laurence; Malabat, Christophe; Jacquier, Alain; Blanquet, Sylvain; Plateau, Pierre

2012-01-01

61

Sodium selenide toxicity is mediated by O2-dependent DNA breaks.  

PubMed

Hydrogen selenide is a recurrent metabolite of selenium compounds. However, few experiments studied the direct link between this toxic agent and cell death. To address this question, we first screened a systematic collection of Saccharomyces cerevisiae haploid knockout strains for sensitivity to sodium selenide, a donor for hydrogen selenide (H(2)Se/HSe(-/)Se(2-)). Among the genes whose deletion caused hypersensitivity, homologous recombination and DNA damage checkpoint genes were over-represented, suggesting that DNA double-strand breaks are a dominant cause of hydrogen selenide toxicity. Consistent with this hypothesis, treatment of S. cerevisiae cells with sodium selenide triggered G2/M checkpoint activation and induced in vivo chromosome fragmentation. In vitro, sodium selenide directly induced DNA phosphodiester-bond breaks via an O(2)-dependent reaction. The reaction was inhibited by mannitol, a hydroxyl radical quencher, but not by superoxide dismutase or catalase, strongly suggesting the involvement of hydroxyl radicals and ruling out participations of superoxide anions or hydrogen peroxide. The (•)OH signature could indeed be detected by electron spin resonance upon exposure of a solution of sodium selenide to O(2). Finally we showed that, in vivo, toxicity strictly depended on the presence of O(2). Therefore, by combining genome-wide and biochemical approaches, we demonstrated that, in yeast cells, hydrogen selenide induces toxic DNA breaks through an O(2)-dependent radical-based mechanism. PMID:22586468

Peyroche, Gérald; Saveanu, Cosmin; Dauplais, Marc; Lazard, Myriam; Beuneu, François; Decourty, Laurence; Malabat, Christophe; Jacquier, Alain; Blanquet, Sylvain; Plateau, Pierre

2012-01-01

62

First principles study of semiconductor to metallic transition in cadmium selenide under high pressure  

NASA Astrophysics Data System (ADS)

First principles calculation were performed using density functional theory calculations with the generalized gradient (GGA) approximations to understand the electronic properties of bulk and thin slab of cadmium selenide. The stability of cadmium selenide thin slab (CdSe (111) and CdSe (100)) was analyzed via surface energy calculation.

Santhosh, M.; Kanagaprabha, S.; Sudhapriyanga, G.; Asvinimeenaatci, A. T.; Palanichamy, R. Rajeswara

2013-06-01

63

Copper Test  

MedlinePLUS

... copper in my diet? 1. Should everyone's copper metabolism be evaluated? General screening for copper concentrations is ... in Man and Animals, Genetic Defects in Copper Metabolism. J. Nutr . 133: 1527S-1531S [On-line journal ...

64

Preparation of iron selenide films by selenization technique  

NASA Astrophysics Data System (ADS)

Iron selenide films have been grown by selenization of evaporated iron thin films. The substrates temperature during selenization was 573 or 723 K. It is shown that whatever the substrate temperature is, for a partial pressure of Se of 3.75×10 -2 Pa, there is selenide compound formation. It is shown that the films are mainly composed of tetragonal FeSe while some crystallites of orthorhombic FeSe 2 are also present. XPS shows that before etching there is some superficial selenium excess while some oxidation of Fe and Se is put in evidence at the surface of the films. However, after etching the superficial oxidation disappears. After annealing for 2 h at 773 K under vacuum the films become crystallized in the hexagonal structure of FeSe, while no FeSe 2 is detected. The Se/Fe ratio tends towards 1. When annealed in the same conditions, but in selenium atmosphere, the films obtained are FeSe 2 films.

Hamdadou, N.; Bernède, J. C.; Khelil, A.

2002-06-01

65

Cadmium Sulfide/Copper Selenide Cell Research Copper Selenide-Based Thin Film Solar Cells. Second Quarterly Technical Progress Report, September 1, 1980-December 1, 1980.  

National Technical Information Service (NTIS)

The objective of this program is to investigate the use of Cu/sub 2-x/Se to produce low cost, high efficiency photovoltaic solar cells. The Cu/sub 2-x/Se films are produced by coevaporation of Cu and Se from separate, individually controlled vapor sources...

S. P. Sauve' R. A. Mickelsen J. M. Stewart W. S. Chen

1980-01-01

66

Cadmium sulfide/copper selenide cell research. Copper selenide-based thin film solar cells. First quarterly technical progress report, June 1-September 1, 1980  

SciTech Connect

The objective of this program is to investigate the use of Cu/sub 2-x/Se to produce low cost, high efficiency photovoltaic solar cells. The goal is to: (1) develop a polycrystalline thin film photovoltaic device capable of 10% conversion efficiency, and (2) demonstrate feasibility of large scale production at a cost of approximately $0.30/watt. The Cu/sub 2-x/Se films are produced by coevaporation of Cu and Se from separate, individually controlled vapor sources onto heated glass substrates. This method gives greater composition controllability and is readily adaptable to large scale production efforts. Two quartz crystal microbalances are used to separately monitor the Cu and Se deposition rates. The structural, electrical, and optical properties of the Cu/sub 2-x/Se films have been measured for deposits made on 250/sup 0/C substrates. The optical absorption measurements shows the material having an indirect band gap of 1.4 ev and a direct gap of 2.2 ev. These values are for stoichiometric indices in the range of 0.17 less than or equal to x less than or equal to 0.26. Hall and conductivity measurements give hole mobilities in the range of 3-7 cm/sup 2//Vsec and hole densities of the order of 4 x 10/sup 22/ cm/sup -3/. For deposits made on substrate at 160/sup 0/C, the mobility is in the range of 3 to 10 cm/sup 2//Vsec and hole densities on the order of 10/sup 19/ to 10/sup 21/ cm/sup -3/ for 0.1 less than or equal to x less than or equal to 0.3. To date, the best cell has photovoltaic characteristics of J/sub sc/ = 11.6 mA/cm/sup 2/, V/sub oc/ = 460 mV, F.F. = 0.62 and eta = 3.3% as tested under simulated AM1 illumination.

Mickelsen, R.A.; Stewart, J.M.; Chen, W.S.

1980-01-01

67

Cadmium sulfide\\/copper selenide cell research copper selenide-based thin film solar cells. Second quarterly technical progress report, September 1, 1980December 1, 1980  

Microsoft Academic Search

The objective of this program is to investigate the use of Cu\\/sub 2-x\\/Se to produce low cost, high efficiency photovoltaic solar cells. The Cu\\/sub 2-x\\/Se films are produced by coevaporation of Cu and Se from separate, individually controlled vapor sources onto heated glass substrates. This method gives greater composition controllability and is readily adaptable to large scale production efforts. Two

S. P. Sauve; R. A. Mickelsen; J. M. Stewart; W. S. Chen

1980-01-01

68

Cadmium sulfide/copper selenide cell research copper selenide-based thin film solar cells. Second quarterly technical progress report, September 1, 1980-December 1, 1980  

SciTech Connect

The objective of this program is to investigate the use of Cu/sub 2-x/Se to produce low cost, high efficiency photovoltaic solar cells. The Cu/sub 2-x/Se films are produced by coevaporation of Cu and Se from separate, individually controlled vapor sources onto heated glass substrates. This method gives greater composition controllability and is readily adaptable to large scale production efforts. Two quartz crystal microbalances are used to separately monitor the Cu and Se deposition rates. The structural, electrical, and optical properties of the Cu/sub 2-x/Se films have been measured for deposits made on 250/sup 0/C substrates. The optical absorption measurements show the material having an indirect band gap of 1.4 eV and a direct gap of 2.2 eV. These values are for stoichiometric indices in the range of 0.17 less than or equal to x less than or equal to 0.26. Hall and conductivity measurements give hole mobilities in the range of 3 to 7 cm/sup 2//Vsec and hole densities of the order of 4 x 10/sup 22/ cm/sup -3/. For deposits made on substrate at 160/sup 0/C, the mobility is in the range of 3 to 10 cm/sup 2//Vsec and hole densities on the order of 10/sup 18/ to 10/sup 21/ cm/sup -3/ for 0.1 less than or equal to x less than or equal to 0.3. To date, the best cell has photovoltaic characteristics of J/sub sc/ = 11.6 mA/cm/sup 2/, V/sub oc/ = 460 mV, F.F. = 0.62 and eta = 3.3% when tested under simulated AM1 illumination. In an effort to improve cell performance, low resistance CdS was used. Cell performance degraded considerably with the low resistance CdS resulting in substantially lower values for both V/sub oc/ and I/sub sc/. It is believed in part that this difficulty can be traced to pinhole defects in the ITO electrode. When the low resistance CdS is deposited on ITO, regions in the CdS appear to be high in Cd where pinholes in the ITO were observed.

Sauve', S.P.; Mickelsen, R.A.; Stewart, J.M.; Chen, W.S.

1980-01-01

69

Influence of Stoichiometry on Impingement Erosion of Lead Sulfide and Zinc Selenide.  

National Technical Information Service (NTIS)

The results of a series of water droplet impingement erosion experiments on lead sulfide and zinc selenide are described. The work with single crystal lead sulfide sought to correlate the mechanisms of surface damage with mechanical strength, lead sulfide...

R. G. Hoagland I. G. Wright

1979-01-01

70

Growth of zinc selenide crystals by physical vapor transport in microgravity  

NASA Technical Reports Server (NTRS)

The growth of single crystals of zinc selenide was carried out by both closed ampoule physical vapor transport and effusive ampoule physical vapor transport (EAPVT). The latter technique was shown to be a much more efficient method for the seeded growth of zinc selenide, resulting in higher transport rates. Furthermore, EAPVT work on CdTe has shown that growth onto /n11/ seeds is advantageous for obtaining reduced twinning and defect densities in II-VI sphalerite materials.

Rosenberger, Franz

1995-01-01

71

Silicon nanowire-silver indium selenide heterojunction photodiodes.  

PubMed

Structural and optoelectronic properties of silicon (Si) nanowire-silver indium selenide (AgInSe2) thin film heterojunctions were investigated. The metal-assisted etching method was employed to fabricate vertically aligned Si nanowire arrays. Stoichiometric AgInSe2 films were then deposited onto the nanowires using co-sputtering and sequential selenization techniques. It was demonstrated that the three-dimensional interface between the Si nanowire arrays and the AgInSe2 thin film significantly improved the photosensitivity of the heterojunction diode compared to the planar reference. The improvements in device performance are discussed in terms of interface state density, reflective losses and surface recombination of the photogenerated carriers, especially in the high-energy region of the spectrum. PMID:23975141

Kulakci, Mustafa; Colakoglu, Tahir; Ozdemir, Baris; Parlak, Mehmet; Unalan, Husnu Emrah; Turan, Rasit

2013-09-20

72

Nanopatterned cadmium selenide Langmuir-Blodgett platform for leukemia detection.  

PubMed

We present results of the studies relating to preparation of Langmuir-Blodgett (LB) monolayers of tri-n-octylphosphine oxide-capped cadmium selenide quantum dots (QCdSe) onto indium-tin oxide (ITO) coated glass substrate. The monolayer behavior has been studied at the air-water interface under various subphase conditions. This nanopatterned platform has been explored to fabricate an electrochemical DNA biosensor for detection of chronic myelogenous leukemia (CML) by covalently immobilizing the thiol-terminated oligonucleotide probe sequence via a displacement reaction. The results of electrochemical response studies reveal that this biosensor can detect target DNA in the range of 10(-6) to 10(-14) M within 120 s, has a shelf life of 2 months, and can be used about 8 times. Further, this nucleic acid sensor has been found to distinguish the CML-positive and the control negative clinical patient samples. PMID:22380657

Sharma, Aditya; Pandey, Chandra M; Matharu, Zimple; Soni, Udit; Sapra, Sameer; Sumana, Gajjala; Pandey, Manoj K; Chatterjee, Tathagat; Malhotra, Bansi D

2012-04-01

73

Facile synthesis of cadmium selenide nanowires and their optical properties  

NASA Astrophysics Data System (ADS)

Well crystalline cadmium selenide (CdSe) nanowires were fabricated on the composite layer of gold and carbon coated Si substrates by a facile chemical vapor deposition method. These nanowires are of single-crystalline hexagonal structure and the average length is up to tens of micrometers. The growth process follows a typical vapor-liquid-solid (VLS) mechanism, and the carbon layer can distinctly enhance the VLS process of the CdSe nanowires. The cathodoluminescence (CL) spectrum of an individual nanowire reveals a strong near-band-edge (NBE) emission and relative weak infrared emission centered at 710 and 981 nm, respectively. The defects-related infrared emission is ascribed to the deep defect donors-related energy level induced by a large amount of Se vacancies.

Du, Yinxiao; Li, Guang-cheng

2011-02-01

74

Copper Peroxide.  

National Technical Information Service (NTIS)

The action of hydrogen superoxide on copper salts in alcoholic solutions is studied. The action of hydrogen peroxide on copper hydroxide in alcoholic suspensions, and the action of ethereal hydrogen peroxide on copper hydroxide are discussed. It is conclu...

L. Moser

1988-01-01

75

Study of Crystal Growth of Zinc Selenide and the Low Temperature Emission Spectra of Undoped and Monovalent Metal Doped Melt Grown Zinc Selenide.  

National Technical Information Service (NTIS)

Recently there has been an increased interest in zinc selenide because of its possible application in the laser window problem. A better understanding of the defect structure of this material is to be desired. It is the purpose of this investigation to ex...

L. C. Greene

1975-01-01

76

Ternary cadmium sulphide selenide quantum dots as new scintillation materials  

SciTech Connect

Monodisperse, highly luminescent, zinc blende, cadmium sulphide selenide (CdS{sub x}Se{sub 1-x}, x=mole fraction of sulphur) quantum dots (QDs) were prepared in gram scales in the particle size range 2?6-4?3 nm. With the varying S and Se contents, emission wavelengths of CdS{sub x}Se{sub 1-x} QDs were tuned from 439 to 581 nm (?exc.=370 nm). QDs were well dispersed in organic solvents and optically transparent plastic scintillators made with up to 10 wt-%QDs in polyvinyltoluene (PVT) were prepared. The result from alpha particle detection indicated the wavelengths match with the sensitivity of the photomultiplier tube. Pulse height peaks of CdS{sub x}Se{sub 1-x} with the wavelength of emission from 439 to 482 nm, appeared around 0?35 (channel no./amplifier gain), with different photon counts. No pulse height peak was observed with QDs that emitted at 505 nm or longer wavelengths. Under studied conditions, CdS0?95Se0?05 was found to be the most efficient scintillator.

Brown, Suree [ORNL; Dai, Sheng [ORNL; Rondinone, Adam Justin [ORNL

2008-01-01

77

Nanoparticle Oxides Precursor Inks for Thin film Copper Indium Gallium Selenide (CIGS) Solar Cells  

Microsoft Academic Search

The paper describes ISET's patented non-vacuum process for low cost mass production of CIGS solar cells. In this process, the water based precursor inks of mixed oxides are deposited on various conducting substrates by a variety of non-vacuum coating techniques. The oxides are converted to CIGS by annealing and the device is completed by deposition of CdS by CBD followed

Vijay K. Kapur; Matthew Fisher; Robin Roe

2001-01-01

78

Impact of secondary barriers on copper-indium-gallium-selenide solar-cell operation  

NASA Astrophysics Data System (ADS)

Thin-film solar cells based on CuInSe2 (CIS) absorber with a band gap of Eg = 1.0 eV and also based on CuIn1-x GaxSe2 (CIGS) alloy absorbers with a band-gap range of Eg = 1.0--1.67 eV are investigated in this work. Intermediate "buffer" semiconductor layers in p-n junctions of CIGS solar cells often improve photodiode properties of the devices. The primary goal of the thesis is to study secondary barriers in the conduction band at the buffer/absorber interface, which may limit current transport and thus reduce the efficiency of the solar cells. The secondary goal is to explore alternative wide-bandgap buffers in CIGS cell structures. CIGS cells with standard CdS buffer layers, and alternative ZnS(O,OH) and InS(O,OH) buffer layers were studied. CdS/CuIn1-xGaxSe2 solar cells with variable Ga content have a range of conduction-band offsets (DeltaEc) in the junction from moderately positive (spike offsets) in CdS/CuInSe2 to moderately negative (cliff offsets) in CdS/CuGaSe 2. Moderate conduction-band spikes in CdS/CIS and low-Ga CdS/CIGS are expected to cause distortions in diode current-voltage (J-V) curves of such solar cells under "red" illumination (hnu < Eg(buffer)); no J-V distortions are expected for high-Ga CdS/CIGS with cliff offsets. These predictions were confirmed in experiments: the distortions were absent for cells with Eg above 1.2--1.3 eV, at which CdS/CIGS DeltaE c is near zero. Experiments and numerical simulations showed that one approach to reduce secondary barriers and J-V distortions in low-Ga high-spike cells is to thin the buffer layer(s). Blue photons (hnu above Eg(buffer)) in the solar spectrum induce photoconductivity in the otherwise compensated buffers, which also results in lowering of the secondary barriers. It was shown that CIGS cells with CdS, InS(O,OH), and ZnS(O,OH) buffers have a similar response to "blue" photons: J-V distortion, if present under red light, is reduced or entirely disappears with blue-light exposure within minutes. The distortion re-appearance without blue light is the order of a thousand times slower. Using wider-gap buffers, such as InS(O,OH) and ZnS(O,OH), was shown to produce higher photocurrents in solar cells. This photocurrent improvement is a central direction in the effort of further increasing efficiencies of thin-film solar cells.

Pudov, Alexei O.

79

Novel Film Formation Pathways for Copper Zinc Tin Selenide for Solar Cell Applications  

NASA Astrophysics Data System (ADS)

Because of the anticipated high demand for Indium, ongoing growth of CIGS technology may be limited. Kesterite materials, which replace In with a Zn/Sn couple, are thought to be a solution to this issue. However, efficiencies are still below the 10% level, and these materials are proving to be complex. Even determination of the bandgap is not settled because of the occurrence of secondary phases. We use a film growth process, 2SSS, which we believe helps control the formation of secondary phases. Under the right growth conditions we find 1/1 Zn/Sn ratios and XRD signatures for Cu2ZnSnSe 4 with no evidence of secondary phases. The optical absorption profile of our films is also a good match to the CIS profile even for films annealed at 500°C. We see no evidence of phase separation. The effect of intentional variation of the Zn/Sn ratio on material and device properties is also presented.

Bendapudi, Sree Satya Kanth

80

Studies of compounds related to copper indium gallium selenide solar cells  

NASA Astrophysics Data System (ADS)

Crystals of Cu(In1-xGax)3Se 5 were grown by the horizontal and vertical Bridgman methods. A non-contact carbon coating was used to avoid the adhesion between Cu(In1-x Gax)3Se5 ingots and the inner ampoule walls. The composition along and across the as grown ingots with different starting Ga contents was analyzed and the results were interpreted by the established pseudobinary phase diagrams. Results of XRD confirmed that the lattice constants of the Cu(In1-xGax)3Se 5 crystals varied linearly with the Ga content. Results of X-ray Laue back-reflection showed that the Cu(In1-xGax) 3Se5 ingots contained large single crystal regions. Hall effect measurements carried out on the grown samples revealed that the Cu(In 1-xGax)3Se5 crystals were highly resistive with rather low carrier concentrations. The morphology of as-grown or cleaved sample surfaces of the Cu(In1-xGax) 3Se5 ingots were also studied under optical microscope and SEM. Metallic Na was, for the first time, introduced into Cu(In1-x Gax)3Se5 compounds to observe the doping effects. The introduction of Na increased the electron concentration significantly for CuIn3Se5 samples (x = 0) but did not show a significant effect on Cu(In1-xGax) 3Se5 samples with x > 0. The increase in electron concentration in the CuIn3Se5 samples after the Na diffusion could be explained by defect generation related to Se and In sites. Crystals of CuInSe2 were also grown by the horizontal Bridgman method for the first time with the addition of metallic sodium. Degradation in crystalline quality and a change of conductivity type from p- to n-type were observed in ingots grown from melts containing more than 0.25 at. % Na. Experiments of Na diffusion were also carried out on CuInSe 2 crystals in a sealed glass ampoule to observe the doping effect. Hot probe measurements indicated that the sodium-treated CuInSe2 samples changed from p-type to n-type. MIS devices were fabricated on the Na-treated CuIn3Se 5 material for electrical characterization. Dark current density-voltage characteristics and differential capacitance-voltage characteristics of the MIS devices were measured at room temperature. An energy band diagram of the MIS devices has been constructed based on the band lineup data reported in the literature. The current transport mechanism was examined and a dominant multi-step tunneling process was proposed. Samples of Cu(In1-xGax)3Se 5 with x ? 0.5 were found to be strongly photoconductive over the wavelength range from 700 to 1100 nm even at room temperature. It was observed that the sensitivity of photoconductivity was greatly influenced by surface preparation conditions. Chemically etched samples showed the highest photoconductivity, believed to be due to the reduced surface recombination velocity. Capacitance measurements were carried out to investigate the interface and bulk properties of ZnO/CdS/Cu(In1-xGax)Se 2 solar cells. Results from the steady state C-V measurements showed evidence of interface or surface states, especially for the samples without annealing. DLTS technique was used to determine the deep levels in Cu(In 1-xGax)Se2 crystals with Ga content varying from 0 to 1. Different deep levels for holes with different DLTS spectra were found in the Cu(In1-xGax)Se2 crystals, with different Ga contents. The present results showed that the Ga content has an important effect on the formation of deep levels in Cu(In1-x Gax)Se2 crystals.

Wang, Haiping

81

Studies of compounds related to copper indium gallium selenide solar cells  

Microsoft Academic Search

Crystals of Cu(In1-xGax)3Se 5 were grown by the horizontal and vertical Bridgman methods. A non-contact carbon coating was used to avoid the adhesion between Cu(In1-x Gax)3Se5 ingots and the inner ampoule walls. The composition along and across the as grown ingots with different starting Ga contents was analyzed and the results were interpreted by the established pseudobinary phase diagrams. Results

Haiping Wang

2002-01-01

82

Contrasting role of antimony and bismuth dopants on the thermoelectric performance of lead selenide.  

PubMed

Increasing the conversion efficiency of thermoelectric materials is a key scientific driver behind a worldwide effort to enable heat to electricity power generation at competitive cost. Here we report an increased performance for antimony-doped lead selenide with a thermoelectric figure of merit of ~1.5 at 800?K. This is in sharp contrast to bismuth doped lead selenide, which reaches a figure of merit of <1. Substituting antimony or bismuth for lead achieves maximum power factors between ~23-27??W?cm(-1)?K(-2) at temperatures above 400?K. The addition of small amounts (~0.25?mol%) of antimony generates extensive nanoscale precipitates, whereas comparable amounts of bismuth results in very few or no precipitates. The antimony-rich precipitates are endotaxial in lead selenide, and appear remarkably effective in reducing the lattice thermal conductivity. The corresponding bismuth-containing samples exhibit smaller reduction in lattice thermal conductivity. PMID:24784991

Lee, Yeseul; Lo, Shih-Han; Chen, Changqiang; Sun, Hui; Chung, Duck-Young; Chasapis, Thomas C; Uher, Ctirad; Dravid, Vinayak P; Kanatzidis, Mercouri G

2014-01-01

83

Contrasting role of antimony and bismuth dopants on the thermoelectric performance of lead selenide  

NASA Astrophysics Data System (ADS)

Increasing the conversion efficiency of thermoelectric materials is a key scientific driver behind a worldwide effort to enable heat to electricity power generation at competitive cost. Here we report an increased performance for antimony-doped lead selenide with a thermoelectric figure of merit of ~1.5 at 800?K. This is in sharp contrast to bismuth doped lead selenide, which reaches a figure of merit of <1. Substituting antimony or bismuth for lead achieves maximum power factors between ~23–27??W?cm?1?K?2 at temperatures above 400?K. The addition of small amounts (~0.25?mol%) of antimony generates extensive nanoscale precipitates, whereas comparable amounts of bismuth results in very few or no precipitates. The antimony-rich precipitates are endotaxial in lead selenide, and appear remarkably effective in reducing the lattice thermal conductivity. The corresponding bismuth-containing samples exhibit smaller reduction in lattice thermal conductivity.

Lee, Yeseul; Lo, Shih-Han; Chen, Changqiang; Sun, Hui; Chung, Duck-Young; Chasapis, Thomas C.; Uher, Ctirad; Dravid, Vinayak P.; Kanatzidis, Mercouri G.

2014-05-01

84

Two-dimensional tin selenide nanostructures for flexible all-solid-state supercapacitors.  

PubMed

Due to their unique electronic and optoelectronic properties, tin selenide nanostructures show great promise for applications in energy storage and photovoltaic devices. Despite the great progress that has been achieved, the phase-controlled synthesis of two-dimensional (2D) tin selenide nanostructures remains a challenge, and their use in supercapacitors has not been explored. In this paper, 2D tin selenide nanostructures, including pure SnSe2 nanodisks (NDs), mixed-phase SnSe-SnSe2 NDs, and pure SnSe nanosheets (NSs), have been synthesized by reacting SnCl2 and trioctylphosphine (TOP)-Se with borane-tert-butylamine complex (BTBC) and 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone. Utilizing the interplay of TOP and BTBC and changing only the amount of BTBC, the phase-controlled synthesis of 2D tin selenide nanostructures is realized for the first time. Phase-dependent pseudocapacitive behavior is observed for the resulting 2D nanostructures. The specific capacitances of pure SnSe2 NDs (168 F g(-1)) and SnSe NSs (228 F g(-1)) are much higher than those of other reported materials (e.g., graphene-Mn3O4 nanorods and TiN mesoporous spheres); thus, these tin selenide materials were used to fabricate flexible, all-solid-state supercapacitors. Devices fabricated with these two tin selenide materials exhibited high areal capacitances, good cycling stabilities, excellent flexibilities, and desirable mechanical stabilities, which were comparable to or better than those reported recently for other solid-state devices based on graphene and 3D GeSe2 nanostructures. Additionally, the rate capability of the SnSe2 NDs device was much better than that of the SnSe NS device, indicating that SnSe2 NDs are promising active materials for use in high-performance, flexible, all-solid-state supercapacitors. PMID:24601530

Zhang, Chunli; Yin, Huanhuan; Han, Min; Dai, Zhihui; Pang, Huan; Zheng, Yulin; Lan, Ya-Qian; Bao, Jianchun; Zhu, Jianmin

2014-04-22

85

Growth of Zinc Selenide Single Crystals by Physical Vapor Transport in Microgravity.  

National Technical Information Service (NTIS)

Growth and characterization studies will be performed on zinc selenide single crystals. The high temperature outgassing behavior of the silica ampoule material will be studied in order to develop a cleaning and bake-out procedure that will minimize the am...

E. E. Anderson F. E. Rosenberger H. Cheng

1990-01-01

86

Draft Genome Sequence of Pseudomonas aeruginosa Strain RB, a Bacterium Capable of Synthesizing Cadmium Selenide Nanoparticles  

PubMed Central

Pseudomonas aeruginosa strain RB is a bacterium capable of synthesizing cadmium selenide (CdSe) nanoparticles and was isolated from a soil sample. Here, we present the draft genome sequence of P. aeruginosa strain RB. To the best of our knowledge, this is the first report of a draft genome of a CdSe-synthesizing bacterium.

Ayano, Hiroyuki; Kuroda, Masashi; Soda, Satoshi

2014-01-01

87

Ellipsometric Determination of the Index of Refraction of Thin Selenide Films.  

National Technical Information Service (NTIS)

Electron beam evaporation was used to produce thin zinc selenide (ZnSe) semiconductor films on glass substrates. Deposition in a vacuum of .000001 Torr yielded films free of apparent defects. A Fortran IV computer program by F. L. McCrackin (National Bure...

J. P. McGorry

1975-01-01

88

Draft Genome Sequence of Pseudomonas aeruginosa Strain RB, a Bacterium Capable of Synthesizing Cadmium Selenide Nanoparticles.  

PubMed

Pseudomonas aeruginosa strain RB is a bacterium capable of synthesizing cadmium selenide (CdSe) nanoparticles and was isolated from a soil sample. Here, we present the draft genome sequence of P. aeruginosa strain RB. To the best of our knowledge, this is the first report of a draft genome of a CdSe-synthesizing bacterium. PMID:24831140

Ayano, Hiroyuki; Kuroda, Masashi; Soda, Satoshi; Ike, Michihiko

2014-01-01

89

Living bio-membrane bi-template route for simultaneous synthesis of lead selenide nanorods and nanotubes  

NASA Astrophysics Data System (ADS)

In this paper, a novel method is reported by which semiconductor materials are synthesized via controlled organism membranes. Semiconductor lead selenide nanorods and nanotubes have been successfully prepared simultaneously through living bio-membrane bi-templates of the mungbean sprout. The lead selenide nanorods are approximately 45 nm in diameter, and up to 1100 nm in length; all of them are single crystalline in structure. Lead selenide nanotubes are 50 nm in diameter, and up to 2000 nm in length, and are poly-crystalline in structure. The characteristics of the products are illustrated by various means, and their possible formation mechanism is explored.

Li, Li; Wu, Qing-Sheng; Ding, Ya-Ping

2004-12-01

90

Spectroscopic ellipsometry studies on vacuum-evaporated zinc selenide thin film  

NASA Astrophysics Data System (ADS)

Optical constants of vacuum-deposited Zinc selenide (ZnSe) film from far infrared to near ultraviolet spectral region (270nm-30?m) have been determined by variable angle spectroscopic ellipsometry. The surface roughness layer and interface layer between ZnSe film and crystalline silicon have been modeled with Bruggeman effective medium approximation (BEMA). To evaluate the microstructure of ZnSe film, X-ray diffraction (XRD) measurements are also performed.

Gao, Weidong

2009-05-01

91

Chemically deposited thin films of sulfides and selenides of antimony and bismuth as solar energy materials  

NASA Astrophysics Data System (ADS)

Chemical bath deposition techniques for bismuth sulfide, bismuth selenide, antimony sulfide, and antimony selenide thin films of about 0.20 - 0.25 micrometer thickness are reported. All these materials may be considered as solar absorber films: strong optical absorption edges, with absorption coefficient, (alpha) , greater than 104 cm-1, are located at 1.31 eV for Bi2Se3, 1.33 eV for Bi2S3, 1.8 eV for Sb2S3, and 1.35 eV for Sb2Se3. As deposited, all the films are nearly amorphous. However, well defined crystalline peaks matching bismuthinite (JCPDS 17- 0320), paraguanajuatite (JCPDS 33-0214), and stibnite (JCPDS 6-0474) and antimony selenide (JCPDS 15-0861) for Bi2S3, Bi2Se3, Sb2S3 and Sb2Se3 respectively, are observed when the films are annealed in nitrogen at 300 degrees Celsius. This is accompanied by a substantial modification of the electrical conductivity in the films: from 10-7 (Omega) -1 cm-1 (in as prepared films) to 10 (Omega) -1 cm-1 in the case of bismuth sulfide and selenide films, and enhancement of photosensitivity in the case of antimony sulfide films. The chemical deposition of a CuS/CuxSe film on these Vx- VIy films and subsequent annealing at 300 degrees Celsius for 1 h at 1 torr of nitrogen leads to the formation of p-type films (conductivity of 1 - 100 (Omega) -1 cm-1) of multinary composition. Among these, the formation of Cu3BiS3 (JCPDS 9-0488) and Cu3SbS4 (JCPDS 35- 0581), CuSbS2 (JCPDS 35-0413) have been clearly detected. Solar energy applications of these films are suggested.

Nair, M. T.; Nair, Padmanabhan K.; Garcia, V. M.; Pena, Y.; Arenas, O. L.; Garcia, J. C.; Gomez-Daza, O.

1997-10-01

92

Synthesis and characterization of new quaternary selenides with ThCr{sub 2}Si{sub 2}-type structure: ACuMnSe{sub 2} (A = K, Rb, Cs)  

SciTech Connect

The new selenides ACuMnSe{sub 2} (A = K, Rb, Cs) were synthesized by heating a mixture of the corresponding alkali metal carbonate, copper oxide, manganese, and elemental selenium at 1,200 K in hydrogen/argon atmosphere. The dark-gray compounds, moderately air-stable, crystallize in the ThCr{sub 2}Si{sub 2}-type structure (space group I4/mmm). Semiconducting properties and short-range antiferromagnetism were observed for all the samples. A comparison of the transport properties with those previously reported for the isostructural sulfides ACuMnSe{sub 2} (A = K, Rb, Cs) confirmed the primary role of the metal-metal bonds in defining the electronic properties of this series.

Oledzka, M.; Ramanujachary, K.V.; Greenblatt, M. [Rutgers-the State Univ. of New Jersey, Piscataway, NJ (United States). Chemistry Dept.] [Rutgers-the State Univ. of New Jersey, Piscataway, NJ (United States). Chemistry Dept.

1998-06-01

93

Acute treatment with bis selenide, an organic compound containing the trace element selenium, prevents memory deficits induced by reserpine in rats.  

PubMed

Taking into account the promising pharmacological actions of (Z)-2,3-bis(4-chlorophenylselanyl) prop-2-en-1-ol) (bis selenide), an organic compound containing the trace element selenium, and the constant search for drugs that improve the cognitive performance, the objective of the present study was to investigate whether bis selenide treatment ameliorates memory deficits induced by reserpine in rats. For this aim, male adult rats received a single subcutaneous injection of reserpine (1 mg/kg), a biogenic amine-depleting agent used to induce memory deficit. After 24 h, bis selenide at doses of 25 and 50 mg/kg was administered to rats by intragastric route, and 1 h later, the animals were submitted to behavior tasks. The effects of acute administration of bis selenide on memory were evaluated by social recognition, step-down passive avoidance, and object recognition paradigms. Exploratory and locomotor activities of rats were determined using the open-field test. Analysis of data revealed that the social memory disruption caused by reserpine was reversed by bis selenide at both doses. In addition, bis selenide, at the highest dose, prevented the memory deficit resulting from reserpine administration to rats in step-down passive avoidance and object recognition tasks. No significant alterations in locomotor and exploratory behaviors were found in animals treated with reserpine and/or bis selenide. Results obtained from distinct memory behavioral paradigms revealed that an acute treatment with bis selenide attenuated memory deficits induced by reserpine in rats. PMID:23132249

Bortolatto, Cristiani Folharini; Guerra Souza, Ana Cristina; Wilhelm, Ethel Antunes; Nogueira, Cristina Wayne

2013-01-01

94

Solid Solution, Mass Transport, and Crystal Growth Studies of Cadmium Iron Selenide.  

NASA Astrophysics Data System (ADS)

Cadmium iron selenide, a semimagnetic semiconductor, has been investigated. Solid solubilities of iron in CdSe were determined at temperatures between 650^ circC and 1100^circC, using the X-ray diffraction Debye-Scherrer powder technique. The solubility limits of Fe in CdSe increase with the temperatures to reach a maximum of about 19.5 mole % FeSe_ {1.24} at 925^circ C, and then decrease with further increasing temperature. Solidification phenomena of the Cd-Fe-Se solid solutions were observed employing optical microscopy, which reveals a typical divorced, eutectic type, nonequilibrium solidification. The combination of the X-ray diffraction and the microscopic investigations yielded a pseudo-binary, eutectic type phase diagram of the Cd-Fe-Se system. Partial pressures of the major vapor species in the Cd-Fe-Se physical and the Cd-Fe-Se-Iodine chemical vapor transport systems were calculated. The partial pressure of gaseous iron species of the PVT system may be neglected compared to those of Cd and Se_2^ecies. This suggests that cadmium iron selenide crystals cannot be grown by the PVT method. For the PVT experiments, using the as-synthesized (CdSe)_ {0.90}(FeSe_{1.24})_{0.10 } source materials, crystals with compositions of 6-8 mole % FeSe_{1.24} were grown at a source temperature of 1000^ circC and a DeltaT of 12^circC. These result are contradictory to the thermodynamic predictions, and were further investigated employing specially purified source materials. Iron contents in the crystals grown in these experiments are close to zero. The transport of iron in the initial mass transport experiments may be due to the chemical impurities (most likely the metal chlorides) in the as-synthesized source materials. Mass transport experiments of the Cd-Fe-Se-Iodine CVT system were performed as a function of source temperatures, the degrees of undercooling (DeltaT), and initial iodine pressures. Promising parameters for the growth of cadmium iron selenide single crystals by the CVT method, e.g., the source temperatures of 800-850 ^circC, initial iodine pressures of 0.5-1.0 atm, and DeltaT of 10 -20^circC, were established. Mass fluxes of cadmium iron selenide were computed using a one -dimensional diffusion equation. The overall trends of the computed mass flux as a function of growth conditions are consistent with the experimental results. However, differences between the theoretical and experimental mass fluxes may be due to the uncertainties of the thermochemical data used and the approximations made in these estimations. Single crystals of cadmium iron selenide with compositions of 6.5-8.5 mole % FeSe_{1.24 } and of about 5 mm edge lengths were successfully grown from the (CdSe)_{0.90 }(FeSe_{1.24})_{0.10} source materials by the CVT method. Compositions of various portions of the bulk crystals are nearly constant along its axis within the error limits, indicating that the crystals possess reasonable compositional uniformity. The indices of the crystal surfaces were obtained by the X -ray diffraction Laue method. The (0001) and (1011) planes usually developed as the natural facets on the surfaces, and (1010) and(1120) as the cleavage planes. A promising chemical etchant for cadmium iron selenide crystals was developed, consisting of about 20 vol. % concentrated HNO_3, 60 vol. % glacial CH _3COOH, and 20 vol. % concentrated H _2SO_4 acids. Etch pit densities of the grown crystals are in the range of 5times10 ^4-rm5times10^5/cm ^2..

Huang, Xuejun

95

High carrier mobility in single ultrathin colloidal lead selenide nanowire field effect transistors.  

PubMed

Ultrathin colloidal lead selenide (PbSe) nanowires with continuous charge transport channels and tunable bandgap provide potential building blocks for solar cells and photodetectors. Here, we demonstrate a room-temperature hole mobility as high as 490 cm(2)/(V s) in field effect transistors incorporating single colloidal PbSe nanowires with diameters of 6-15 nm, coated with ammonium thiocyanate and a thin SiO(2) layer. A long carrier diffusion length of 4.5 ?m is obtained from scanning photocurrent microscopy (SPCM). The mobility is increased further at lower temperature, reaching 740 cm(2)/(V s) at 139 K. PMID:22823181

Graham, Rion; Yu, Dong

2012-08-01

96

Synthesis of Silver Selenide Bicomponent Nanoparticles by a Novel Technique: Laser-Solid-Liquid Ablation  

NASA Astrophysics Data System (ADS)

A novel laser-solid-liquid ablation technique has been developed to synthesize Ag 2Se nanoparticles from silver nitrate and selenium powder in a mixed solvent of 2-propanol and ethylenediamine. The products were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). The XRD indicated that the products were the single phase of silver selenide. The TEM images revealed that the as-prepared Ag 2Se grains were homogeneous and spherical, and their average size was about 30 nm. This novel technique can be extended to prepare other nanoparticles of various compositions.

Jiang, Z. Y.; Huang, R. B.; Xie, S. Y.; Xie, Z. X.; Zheng, L. S.

2001-09-01

97

Ovonic switching in tin selenide thin films. Ph.D. Thesis  

NASA Technical Reports Server (NTRS)

Amorphous tin selenide thin films which possess Ovonic switching properties were fabricated using vacuum deposition techniques. Results obtained indicate that memory type Ovonic switching does occur in these films the energy density required for switching from a high impedance to a low impedance state is dependent on the spacing between the electrodes of the device. The switching is also function of the magnitude of the applied voltage pulse. A completely automated computer controlled testing procedure was developed which allows precise control over the shape of the applied voltage switching pulse. A survey of previous experimental and theoretical work in the area of Ovonic switching is also presented.

Baxter, C. R.

1974-01-01

98

Dissimilatory Reduction of Elemental Selenium to Selenide in Sediments and Anaerobic Cultures of Selenium Respiring Bacteria  

NASA Astrophysics Data System (ADS)

Selenium contaminated environments often contain elemental Se (Se0) in their sediments that originates from dissimilatory reduction of Se oxyanions. The forms of Se in sedimentary rocks similarly contain high proportions of Se0, but much of the Se is also in the form of metal selenides, Se-2. It is not clear if the occurrence of these selenides is due to microbial reduction of Se0, or some other biological or chemical process. In this investigation we examined the possibility that bacterial respiratory reduction of Se0 to Se-2 could explain the presence of the latter species in sedimentary rocks. We conducted incubations of anoxic sediment slurries amended with different forms of Se0. High levels of Se0 (mM) were added to San Francisco Bay sediments in order to enhance the detection of soluble HSe-, which was precipitated with Cu2+ then redissolved and quantified by ICP-MS. Concentrations of HSe- were highest in live samples amended with red amorphous Se0 formed by either microbial reduction of Se+4 ("biogenic Se0") or by chemical oxidation of H2Se(g) ("chem. Se0"); very little HSe- was formed in those amended with black crystalline Se0, indicating the general lack of reactivity of this allotrope. Controls poisoned with 10% formalin did not produce HSe- from additions of chem. Se0. Reduction of both forms of red amorphous Se0 to HSe- occurred vigorously in growing cultures of Bacillus selenitireducens, an anaerobic halophile previously isolated from sediments of Mono Lake, CA. Up to 73% and 68% of red amorphous, biogenic Se0 or chem. Se0, respectively, was reduced to HSe- during growth of B. selenitireducens, (incubation time ~ 200 hrs): oxidation of lactate to acetate as well as cell density increases indicated that a dissimilatory reduction pathway was likely. Reduction was most enhanced when cells were previously grown on elemental sulfur or Se+4. In contrast to the growth experiments, washed cell suspensions of B. selenitireducens exhibited no HSe- production when amended with red amorphous or black Se0; however, they could convert up to 34% of added Se+4 to HSe- after its complete reduction to Se0 first occurred. These findings indicate that reduction of Se0 in sediments to HSe- or metal selenides is a bacterial dissimilatory processes, that explains the presence of selenides in some sedimentary rocks.

Herbel, M. J.; Switzer-Blum, J.; Oremland, R. S.

2001-12-01

99

Ruthenium selenide catalysts for cathodic oxygen reduction in direct methanol fuel cells  

Microsoft Academic Search

The oxygen reduction reaction in sulphuric acid on commercial carbon supported platinum and ruthenium catalysts as well as\\u000a on a home-made carbon supported ruthenium selenide catalysts (RuSe\\u000a x\\u000a \\/C) was investigated. The RuSe\\u000a x\\u000a \\/C catalysts were synthesised using similar procedures to those found in the literature. A dependency of H2O2 formation on the selenium content was found using the

Alexander Racz; Petra Bele; Carsten Cremers; Ulrich Stimming

2007-01-01

100

Enhanced performance of hybrid solar cells using longer arms of quantum cadmium selenide tetrapods  

NASA Astrophysics Data System (ADS)

We demonstrate that enhanced device performance of hybrid solar cells based on tetrapod (TP)-shaped cadmium selenide (CdSe) nanoparticles and conjugated polymer of poly (3-hexylthiophene) (P3HT) can be obtained by using longer armed tetrapods which aids in better spatial connectivity, thus decreasing charge hopping events which lead to better charge transport. Longer tetrapods with 10 nm arm length lead to improved power conversion efficiency of 1.12% compared to 0.80% of device having 5 nm short-armed tetrapods:P3HT photoactive blends.

Lee, Kyu-Sung; Kim, Inho; Gullapalli, Sravani; Wong, Michael S.; Jabbour, Ghassan E.

2011-11-01

101

Copper Cleanup  

NSDL National Science Digital Library

In this hands-on experiment, kids use chemistry to explore whether acids or bases are better at restoring a pennyâs shine. Kids follow the scientific process to test a common household cleaning products alongside ketchup, cola, and other kitchen staples, and may be surprised by the results! A downloadable data sheet is available on the Copper Cleanup activity resources page.

Wgbh

2010-01-01

102

Two-step synthesis of silver selenide semiconductor with a linear magnetoresistance effect  

NASA Astrophysics Data System (ADS)

A two-step synthesis method for polycrystalline ?-silver selenide (?-Ag2Se) was developed. In the first step, nanopowder was prepared using a chemical conversion method at room temperature. In the second step, the nanopowder was compressed and then the bulk Ag2Se was fabricated by the solid-state sintering process. The crystalline phase and morphology were examined. The results showed that ?-Ag2Se was fast fabricated at room temperature. The dense polycrystalline Ag-rich Ag2Se was synthesized successfully at 450 °C for 0.5 h under Argon flow. For the polycrystalline, the electronic properties and transverse magnetoresistance (TMR) in a pulsed magnetic field were investigated. The samples displayed n-type semiconducting behaviors and a critical temperature with a broaden temperature range of 140-150 K. Also, it presented a positive and nearly linear dependence on magnetic field H at H ? Hc (crossover field) ranging from 2 to 20 T. Moreover, the linear dependence of TMR at strong field was non-saturating up to 35 T. Combining with the observation of morphology, it is thought that this unusual TMR effect was caused by slightly excess Ag. This new synthesis method provided a potential route to synthesize nonstoichiometric silver selenide.

Yang, Fengxia; Xiong, Shuangtao; Xia, Zhengcai; Liu, Fengxian; Han, Chong; Zhang, Duanming

2012-12-01

103

Characterization of nanostructured iron selenide thin films grown by chemical route at room temperature  

SciTech Connect

Highlights: ? Nanostructured FeSe thin films were successfully synthesized at room temperature by CBD method. ? The XRD and EDAX characterization confirms nanocrystalline nature of FeSe. ? The SEM and AFM show microporous morphology with nanorods and nanoplates of FeSe. -- Abstract: Iron selenide thin films have been deposited onto glass substrates by using chemical bath deposition technique. Structural characterization of iron selenide thin films was carried out by means of X-ray diffraction and Fourier transforms infrared spectrum. The morphological characterization of FeSe thin film was carried out using scanning electron microscopy and atomic force microscopy, which revealed porous grain morphology of FeSe with some nano rectangular rods and plates grown on it. The as-deposited thin films exhibited optical band gap energy 2.60 eV. The as deposited FeSe thin films are semiconducting in nature with p-type electrical conductivity. The room temperature electrical resistivity is of the order of 1.1 × 10{sup 5} ?-cm with activation energy 0.26 and 0.95 eV, respectively, in low and high temperature region.

Ubale, A.U., E-mail: ashokuu@yahoo.com [Nanostructured Thin Film Materials Laboratory, Department of Physics, Govt. Vidarbha Institute of Science and Humanities, VMV Road, Amravati 444604, Maharashtra (India); Sakhare, Y.S.; Belkedkar, M.R. [Nanostructured Thin Film Materials Laboratory, Department of Physics, Govt. Vidarbha Institute of Science and Humanities, VMV Road, Amravati 444604, Maharashtra (India)] [Nanostructured Thin Film Materials Laboratory, Department of Physics, Govt. Vidarbha Institute of Science and Humanities, VMV Road, Amravati 444604, Maharashtra (India); Singh, Arvind [Department of Physics, Institute of Chemical Technology, Matunga, Mumbai 400 019 (India)] [Department of Physics, Institute of Chemical Technology, Matunga, Mumbai 400 019 (India)

2013-02-15

104

Wide range photodetector based on catalyst free grown indium selenide microwires.  

PubMed

We first report the catalyst free growth of indium selenide microwires through a facile approach in a horizontal tube furnace using indium and selenium elemental powders as precursors. The synthesized microwires are ?-phase, high quality, single crystalline and grown along the [112?0] direction. The wires have a uniform diameter of ?1 ?m and lengths of several micrometers. Photodetectors fabricated from synthesized microwires show reliable and stable photoresponse exhibiting a photoresponsivity of 0.54 A/W, external quantum efficiency of 1.23 at 633 nm with 4 V bias. The photodetector has a reasonable response time of 0.11 s and specific detectivity of 3.94 × 10(10) Jones at 633 nm with a light detection range from 350 to 1050 nm, covering the UV-vis-NIR region. The photoresponse shown by single wire is attributed to direct band gap (Eg = 1.3 eV) and superior single crystalline quality. The photoresponsive studies of single microwires clearly suggest the use of this new and facile growth technique without using catalysts for fabrication of indium selenide microwires in next-generation sensors and detectors for commercial and military applications. PMID:24836455

Ali, Zulfiqar; Mirza, Misbah; Cao, Chuanbao; Butt, Faheem K; Tanveer, M; Tahir, Muhammad; Aslam, Imran; Idrees, Faryal; Safdar, Muhammad

2014-06-25

105

A hysteresis effect in photoconductive cadmium selenide and its use in a solid-state image storage device  

Microsoft Academic Search

A brief description of a new hysteresis effect in cadmium selenide photoconductive powder will be given. Photocurrent plotted as a function of voltage has the form of a hysteresis loop, with triggering from low to high currents occurring at a voltage depending on the incident light level. At a suitably chosen voltage, triggering from low to high currents occurs with

F. H. Nicoll

1957-01-01

106

Dispersion strengthened copper  

DOEpatents

A composition of matter is described which is comprised of copper and particles which are dispersed throughout the copper, where the particles are comprised of copper oxide and copper having a coating of copper oxide. A method for making this composition of matter is also described. This invention relates to the art of powder metallurgy and, more particularly, it relates to dispersion strengthened metals.

Sheinberg, H.; Meek, T.T.; Blake, R.D.

1990-01-09

107

Copper peroxide  

NASA Technical Reports Server (NTRS)

A number of oxidizing agents, including chlorine, bromine, ozone and other peroxides, were allowed to act on copper solutions with the intention of forming copper peroxide. The only successful agent appears to be hydrogen peroxide. It must be used in a neutral 50 to 30 percent solution at a temperature near zero. Other methods described in the literature apparently do not work. The excess of hydrogen must be quickly sucked out of the brown precipitate, which it is best to wash with alcohol and ether. The product, crystalline under a microscope, can be analyzed only approximately. It approaches the formula CuO2H2O. In alkaline solution it appears to act catalytically in causing the decomposition of other peroxides, so that Na2O2 cannot be used to prepare it. On the addition of acids the H2O2 is regenerated. The dry substance decomposes much more slowly than the moist but is not very stable.

Moser, L.

1988-01-01

108

Phase transition and high temperature thermoelectric properties of copper selenide Cu2-xSe (0 <= x <= 0.25)  

NASA Astrophysics Data System (ADS)

With good electrical properties and an inherently complex crystal structure, Cu2-xSe is a potential “phonon glass electron crystal" thermoelectric material that has previously not attracted much interest. In this study, Cu2-xSe (0 <= x <= 0.25) compounds were synthesized by a melting-quenching method, and then sintered by spark plasma sintering to obtain bulk material. The effect of Cu content on the phase transition and thermoelectric properties of Cu2-xSe were investigated in the temperature range of 300 K-750 K. The results of X-ray diffraction at room temperature show that Cu2-xSe compounds possess a cubic structure with a space group of Fm3m(#225) when 0.15 <= x <= 0.25, whereas they adopt a composite of monoclinic and cubic phases when 0 <= x <= 0.15. The thermoelectric property measurements show that with increasing Cu content, the electrical conductivity decreases, the Seebeck coefficient increases and the thermal conductivity decreases. Due to the relatively good power factor and low thermal conductivity, the nearly stoichiometric Cu2Se compound achieves the highest ZT of 0.38 at 750 K. It is expected that the thermoelectric performance can be further optimized by doping appropriate elements and/or via a nanostructuring approach.

Xiao, Xing-Xing; Xie, Wen-Jie; Tang, Xin-Feng; Zhang, Qing-Jie

2011-08-01

109

A study of the stability of cadmium sulfide/copper sulfide solar cells  

NASA Astrophysics Data System (ADS)

The results of an experimental study of the intrinsic degradation mechanisms in cadmium sulfide/copper sulfide solar cells are reported. Behavior during degradation of both voltage and current is described. No major trend of fill factor degradation was observed for the primary cells used in this study, although significant degradation of this parameter has been observed in other cell types. The voltage degradation can be recovered by 'resting' or reverse biasing the cells, while recovery of the degradation of the light generated current requires refiring. Statistical summaries of degradation data, including degradation rates, for cell groups exposed to combinations of stresses (temperature, load, illumination, roof-top ambient) are presented. These indicate that open-circuit is the most stressful load condition. Possible mechanisms and causative factors for the observed degradation modes are discussed. Preliminary results of a study of the stability of cadmium sulfide/copper-indium selenide photovoltaic devices are also presented.

Noel, G. T.; Gaines, G. B.; Richard, N. A.

110

Copper Extraction Demonstration  

NSDL National Science Digital Library

Summary This demonstration uses sulfuric acid and crushed copper ore (malachite) to produce a solution of copper sulfate and carbonic acid in a beaker. When a freshly sanded nail is dropped into the copper sulfate ...

111

Silica encapsulation of thiol-stabilized lead selenide (PbSe) quantum dots in aqueous solution  

PubMed Central

Silica encapsulation of lead selenide quantum dots (PbSe QDs) in aqueous solution is reported. Thioglycolic acid (TGA) stabilized PbSe QDs were modified with 3-mercaptopropyl trimethoxysilane (MPS) through vigorous stirring in water for 18–24 h in alkaline solution (pH 10.4–10.6). Silica shell was developed by controlled deposition and precipitation of silicates from sodium silicate solution onto MPS modified QDs surfaces. TEM images showed multiple PbSe QDs encapsulated in silica shell. The size of PbSe-SiO2 core-shell nanocrystals was estimated to be 25–30 nm by TEM. Elemental compositions (Pb, Se and Si) were investigated by EDX analysis. The purified colloids of PbSe-SiO2 QDs were stable for months when kept at 4 °C.

Primera-Pedrozo, Oliva M.; Ates, Mehmet; Arslan, Zikri

2013-01-01

112

Silica encapsulation of thiol-stabilized lead selenide (PbSe) quantum dots in aqueous solution.  

PubMed

Silica encapsulation of lead selenide quantum dots (PbSe QDs) in aqueous solution is reported. Thioglycolic acid (TGA) stabilized PbSe QDs were modified with 3-mercaptopropyl trimethoxysilane (MPS) through vigorous stirring in water for 18-24 h in alkaline solution (pH 10.4-10.6). Silica shell was developed by controlled deposition and precipitation of silicates from sodium silicate solution onto MPS modified QDs surfaces. TEM images showed multiple PbSe QDs encapsulated in silica shell. The size of PbSe-SiO2 core-shell nanocrystals was estimated to be 25-30 nm by TEM. Elemental compositions (Pb, Se and Si) were investigated by EDX analysis. The purified colloids of PbSe-SiO2 QDs were stable for months when kept at 4 °C. PMID:23729944

Primera-Pedrozo, Oliva M; Ates, Mehmet; Arslan, Zikri

2013-07-01

113

Controllable synthesis of metal selenide heterostructures mediated by Ag2Se nanocrystals acting as catalysts  

NASA Astrophysics Data System (ADS)

Ag2Se nanocrystals were demonstrated to be novel semiconductor mediators, or in other word catalysts, for the growth of semiconductor heterostructures in solution. This is a result of the unique feature of Ag2Se as a fast ion conductor, allowing foreign cations to dissolve and then to heterogrow the second phase. Using Ag2Se nanocrystals as catalysts, dimeric metal selenide heterostructures such as Ag2Se-CdSe and Ag2Se-ZnSe, and even multi-segment heterostructures such as Ag2Se-CdSe-ZnSe and Ag2Se-ZnSe-CdSe, were successfully synthesized. Several interesting features were found in the Ag2Se based heterogrowth. At the initial stage of heterogrowth, a layer of the second phase forms on the surface of an Ag2Se nanosphere, with a curved junction interface between the two phases. With further growth of the second phase, the Ag2Se nanosphere tends to flatten the junction surface by modifying its shape from sphere to hemisphere in order to minimize the conjunct area and thus the interfacial energy. Notably, the crystallographic relationship of the two phases in the heterostructure varies with the lattice parameters of the second phase, in order to reduce the lattice mismatch at the interface. Furthermore, a small lattice mismatch at the interface results in a straight rod-like second phase, while a large lattice mismatch would induce a tortuous product. The reported results may provide a new route for developing novel selenide semiconductor heterostructures which are potentially applicable in optoelectronic, biomedical, photovoltaic and catalytic fields.Ag2Se nanocrystals were demonstrated to be novel semiconductor mediators, or in other word catalysts, for the growth of semiconductor heterostructures in solution. This is a result of the unique feature of Ag2Se as a fast ion conductor, allowing foreign cations to dissolve and then to heterogrow the second phase. Using Ag2Se nanocrystals as catalysts, dimeric metal selenide heterostructures such as Ag2Se-CdSe and Ag2Se-ZnSe, and even multi-segment heterostructures such as Ag2Se-CdSe-ZnSe and Ag2Se-ZnSe-CdSe, were successfully synthesized. Several interesting features were found in the Ag2Se based heterogrowth. At the initial stage of heterogrowth, a layer of the second phase forms on the surface of an Ag2Se nanosphere, with a curved junction interface between the two phases. With further growth of the second phase, the Ag2Se nanosphere tends to flatten the junction surface by modifying its shape from sphere to hemisphere in order to minimize the conjunct area and thus the interfacial energy. Notably, the crystallographic relationship of the two phases in the heterostructure varies with the lattice parameters of the second phase, in order to reduce the lattice mismatch at the interface. Furthermore, a small lattice mismatch at the interface results in a straight rod-like second phase, while a large lattice mismatch would induce a tortuous product. The reported results may provide a new route for developing novel selenide semiconductor heterostructures which are potentially applicable in optoelectronic, biomedical, photovoltaic and catalytic fields. Electronic supplementary information (ESI) available: Fig. S1-S8 and Table S1. See DOI: 10.1039/c3nr03601d

Zhou, Jiangcong; Huang, Feng; Xu, Ju; Wang, Yuansheng

2013-09-01

114

A novel one-pot route for the synthesis of water-soluble cadmium selenide nanoparticles  

NASA Astrophysics Data System (ADS)

A novel, facile one-pot synthetic route to highly water dispersible and potentially biocompatible CdSe nanoparticles is reported. The monodispersed CdSe particles are passivated by cysteine, with water being the solvent. This route involves the reaction of selenium powder with sodium borohydride to produce selenide ions, followed by the addition of a cadmium salt and L-cysteine ethyl ester hydrochloride. The nanoparticles formed show quantum confinement fluorescing in the blue region. Fourier transform infrared spectroscopy study shows that CdSe nanoparticles are capped through mercapto group of the amino acid cysteine whilst its free amino and carboxylate groups make it amenable to bioconjugation establishing the possibility of using these as fluorescent biomarkers. High-resolution transmission electron spectroscopy images of these materials show well-defined, crystalline nanosized particles. Energy dispersive spectroscopy spectra confirm the presence of the corresponding elements.

Oluwafemi, S. O.; Revaprasadu, N.; Ramirez, A. J.

2008-06-01

115

High performance Li2S-P2S5 solid electrolyte induced by selenide  

NASA Astrophysics Data System (ADS)

Nonhygroscopic selenide of Ge0.35Ga0.05Se0.60 was introduced into the Li2S-P2S5 system by partially substituting P2S5 to form a new lithium ion solid electrolyte. And the electrochemical property of the as-prepared solid electrolyte was systematically studied. The optimal sample achieved a wide electrochemical window over 6.5 V and fairly high Li-ion conductivity of 1.5 × 10-3 S cm-1 at ambient temperature. And it is also verified that the studied electrolyte was much stable when contacts with lithium metal at 100 °C for 4 h. This new finding may provide an electrolyte material for developing all-solid-state lithium batteries.

Liu, Zhanqiang; Tang, Yufeng; Wang, Yaoming; Huang, Fuqiang

116

The growth of zinc selenide single crystals by physical vapor transport in microgravity  

NASA Technical Reports Server (NTRS)

Growth and characterization studies will be performed on zinc selenide single crystals. The high temperature outgassing behavior of the silica ampoule material will be studied in order to develop a cleaning and bake-out procedure that will minimize the amount of impurities introduced into the vapor from the ampoule materials and in particular during the seal-off procedure. The outgassing behavior of the ZnSe starting material will be studied during high vacuum refinement at elevated temperatures in order to develop a temperature pressure program that will optimize the removal of impurities while minimizing a shift in stoichiometry due to preferred evaporation of the higher fugacity component. The mass spectrometer system was completed, and after calibration, will be used to perform the above tasks. The system and its operation is described in detail.

Anderson, Elmer E.; Rosenberger, Franz E.; Cheng, Hai-Yuin

1990-01-01

117

Novel chemical synthetic route and characterization of zinc selenide thin films  

NASA Astrophysics Data System (ADS)

Zinc selenide (ZnSe) thin film have been deposited using chemical bath method on non-conducting glass substrate in a tartarate bath containing zinc sulfate, ammonia, hydrazine hydrate, sodium selenosulfate in an aqueous alkaline medium at 333 K. The deposition parameter of the ZnSe thin film is interpreted in the present investigation. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), optical absorption, electrical measurements, atomic absorption spectroscopy (AAS). The ZnSe thin layers grown with polycrystalline zinc blende system along with some amorphous phase present in ZnSe film. The direct optical band gap ‘Eg’ for the film was found to be 2.81 eV and electrical conductivity in the order of 10-8(? cm)-1 with n-type conduction mechanism.

Hankare, P. P.; Chate, P. A.; Delekar, S. D.; Asabe, M. R.; Mulla, I. S.

2006-11-01

118

Dielectric Properties of Cadmium Selenide (CdSe) Nanoparticles synthesized by solvothermal method  

NASA Astrophysics Data System (ADS)

Synthesis of nanoparticles of cadmium selenide (CdSe) was carried out using solvothermal method with cadmium nitrate and sodium selenite as precursors. Hydrazine hydrate and ethylenediamine tetra acetic acid were used as the capping agent to control the size of the nanoparticles. As their size decreases to their Bohr radius (usually around a few nanometers), all electronic properties change, and equally important, become dependent on size. In this size, a semiconductor nanoparticle transition occurs in which the electrons and holes are confined beyond their natural Bohr radius. The properties become dependent not only on size, but also on shape. The crystalline nature and particle size of the samples were characterized by Powder X-ray diffraction analysis (XRD). The morphology of prepared CdSe nanoparticles was studied by scanning electron microscope. Dielectric studies were carried out for the pelletized sample of CdSe nanoparticles. The ac conductivity of CdSe nanoparticle has been studied. The obtained results are discussed.

Suresh, S.; Arunseshan, C.

2013-01-01

119

Achieving higher TC superconductivity in dense cuprates, iron selenides, and hydrocarbons  

NASA Astrophysics Data System (ADS)

Pressure plays an essential role in inducing or tuning superconductivity as well as shedding insight on the mechanism of superconductivity. There are much rich phase diagrams in unconventional superconductors under pressure. Finding ways to control the quantum coherence properties to have a higher critical temperature TC than the material has remains a challenge. Here we will talk about our recent experimental efforts in achieving higher temperature superconductivity in cuprates, iron selenides, and hydrocarbons. We will show how to enhance remarkably TC through the pressure tuning of competing electronic order in multilayer cuprates [1] and how to have superconductivity in two distinct regimes in iron selenides [2,3]. We will present a discovery of an enhancement of TC at more than doubled ambient value in a highly compressed aromatic hydrocarbon [4]. Our results have important implications for designing and engineering superconductors with much higher TCs at ambient conditions.[4pt] [1] X. J. Chen, V. V. Struzhkin, Y. Yu, A. F. Goncharov, C. T. Lin, H. K. Mao, and R. J. Hemley, Nature 466, 950-953 (2010).[0pt] [2] L. L. Sun, X. J. Chen, J. Guo, P. W. Gao, H. D. Wang, M. H. Fang, X. L. Chen, G. F. Chen, Q. Wu, C. Zhang, D. C. Gu, X. L. Dong, K. Yang, A. G. Li, X. Dai, H. K. Mao, and Z. X. Zhao, Nature 483, 67-69 (2012) .[0pt] [3] X. J. Chen, Q. Huang, S. B. Wang, J. X. Zhu, W. Bao, M. H. Fang, J. B. Zhang, L. Y. Tang, Y. M. Xiao, P. Chaw, J. Shu, W. L. Mao, V. V. Struzhkin, R. J. Hemley, and H. K. Mao, unpublished.[0pt] [4] X. J. Chen, X. F. Wang, Z. X. Qin, H. Wu, Q. Z. Huang, T. Muramatsu, J. J. Ying, P. Cheng, Z. J. Xiang, X. H. Chen, W. G. Yang, V. V. Struzhkin, and H. K. Mao, unpublished.

Chen, Xiao-Jia

2013-03-01

120

Synthesis and characterization of a nickel selenide series via a hydrothermal process  

NASA Astrophysics Data System (ADS)

A series of nickel selenides (NiSe and NiSe2) has been successfully synthesized from the reaction of SeCl4 with NiCl2?6H2O in the presence of cetyltrimethyl ammonium bromide (CTAB) as surfactant and hydrazine hydrate (N2H4?H2O) as reductant at 180 °C for 12 h through a simple hydrothermal method. The morphology, phase structure and composition of NixSey can be controlled by adjusting the Ni/Se ratio of the raw materials, the quantity of reductant, the reaction temperature and so forth. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS) analysis. It was found that when the ratio of Ni/Se is 1:1 or 3:2, flower-like assemblies of NiSe nanosheets are formed, at 180 °C for 12 h. When the ratio of Ni/Se is 1:2 at 180 °C, the products are found to be the mixture of hexagonal NiSe and cubic NiSe2. With decrease of nickel content in molar ratio of 1:2 (Ni:Se), nanospheres are agglomerated and microstructures are formed. With the reaction temperature decreasing from 180 °C to 120 °C, we reach pure NiSe2 nanoparticles. The formation mechanism of the nickel selenides has been investigated in detail by means of XRD and SEM analyses.

Sobhani, Azam; Salavati-Niasari, Masoud

2014-01-01

121

Preparing Copper Powder from Cemented Copper.  

National Technical Information Service (NTIS)

Techniques were developed for preparing metallurgical-grade copper powder from industrially produced cement copper. Flotation was used for rejecting discrete gangue particles, acid leaching to remove residual iron and aluminum, hydrogen reduction to elimi...

J. K. Winter L. G. Evans R. D. Groves

1971-01-01

122

Role of copper transporters in copper homeostasis.  

PubMed

Copper is a redox active metal that is essential for biological function. Copper is potentially toxic; thus, its homeostasis is carefully regulated through a system of protein transporters. Copper is taken up across the lumen surface of the small intestinal microvilli as cuprous ion by Ctr1. Cupric ion may also be taken up, but those processes are less well understood. Within the cell, intestinal as well as others, copper is escorted to specific compartments by metallochaperones. One, CCS, donates copper to superoxide dismutase. Another, COX17, delivers copper to additional chaperones within the mitochondria for synthesis of cytochrome c oxidase. A third chaperone, Atox1, delivers copper to the secretory pathway by docking with 2 P-type ATPases. One, ATP7A, is the protein nonfunctional in Menkes disease. This protein is required for cuproenzyme biosynthesis, and in the enterocyte it is required for copper efflux to portal blood. The second, ATP7B, predominantly expressed in liver, is required for copper metallation of ceruloplasmin and biliary copper excretion. Mutations in ATP7B lead to Wilson disease. Additional intracellular hepatic copper-binding proteins COMMD1 (copper metabolism MURR1 domain) and XIAP (X-linked inhibitor of apoptosis protein) may also be required for excretion. Other proteins involved in copper homeostasis may include metallothionein and amyloid precursor protein. Plasma protein transport of copper from the intestine to liver and in systemic circulation probably includes both albumin and alpha2-macroglobulin. Changes in the expression of copper "transporters" may be useful to monitor copper status of humans, provided a suitable cell type can be sampled. PMID:18779302

Prohaska, Joseph R

2008-09-01

123

Copper allergy from dental copper amalgam?  

PubMed

A 65-year-old female was investigated due to a gradually increasing greenish colour change of her plastic dental splint, which she used to prevent teeth grinding when sleeping. Furthermore, she had noted a greenish/bluish colour change on the back of her black gloves, which she used to wipe her tears away while walking outdoors. The investigation revealed that the patient had a contact allergy to copper, which is very rare. She had, however, had no occupational exposure to copper. The contact allergy may be caused by long-term exposure of the oral mucosa to copper from copper-rich amalgam fillings, which were frequently used in childhood dentistry up to the 1960s in Sweden. The deposition of a copper-containing coating on the dental splint may be caused by a raised copper intake from drinking water, increasing the copper excretion in saliva, in combination with release of copper due to electrochemical corrosion of dental amalgam. The greenish colour change of the surface of the splint is probably caused by deposition of a mixture of copper compounds, e.g. copper carbonates. Analysis by the X-ray diffraction technique indicates that the dominant component is copper oxide (Cu2O and CuO). The corresponding greenish/bluish discoloration observed on the back of the patient's gloves may be caused by increased copper excretion in tears. PMID:12083714

Gerhardsson, Lars; Björkner, Bert; Karlsteen, Magnus; Schütz, Andrejs

2002-05-01

124

Hybrid photovoltaic structures based on polymer\\/chemically grown cadmium selenide films: effect of silicotungstic acid on the junction properties  

Microsoft Academic Search

Thin cadmium selenide layers were deposited by chemical bath deposition (CBD) on various substrates: glass, gold, indium tin oxide (ITO), and poly(3-methylthiophene) (PMeT), an organic conducting polymer. In all cases, CdSe adhered strongly to the substrate. X-ray diffraction, scanning electron microscopy, and optical transmission revealed an effect of the substrate nature upon the structural and optical properties of CdSe films.

C. Sène; H. Nguyen Cong; M. Dieng; P. Chartier

2000-01-01

125

COPPER CORROSION RESEARCH UPDATE  

EPA Science Inventory

Copper release and corrosion related issues continue to be important to many water systems. The objective of this presentation is to discuss the current state of copper research at the USEPA. Specifically, the role of aging on copper release, use of phosphates for copper corrosio...

126

Copper and Copper Proteins in Parkinson's Disease  

PubMed Central

Copper is a transition metal that has been linked to pathological and beneficial effects in neurodegenerative diseases. In Parkinson's disease, free copper is related to increased oxidative stress, alpha-synuclein oligomerization, and Lewy body formation. Decreased copper along with increased iron has been found in substantia nigra and caudate nucleus of Parkinson's disease patients. Copper influences iron content in the brain through ferroxidase ceruloplasmin activity; therefore decreased protein-bound copper in brain may enhance iron accumulation and the associated oxidative stress. The function of other copper-binding proteins such as Cu/Zn-SOD and metallothioneins is also beneficial to prevent neurodegeneration. Copper may regulate neurotransmission since it is released after neuronal stimulus and the metal is able to modulate the function of NMDA and GABA A receptors. Some of the proteins involved in copper transport are the transporters CTR1, ATP7A, and ATP7B and the chaperone ATOX1. There is limited information about the role of those biomolecules in the pathophysiology of Parkinson's disease; for instance, it is known that CTR1 is decreased in substantia nigra pars compacta in Parkinson's disease and that a mutation in ATP7B could be associated with Parkinson's disease. Regarding copper-related therapies, copper supplementation can represent a plausible alternative, while copper chelation may even aggravate the pathology.

Rivera-Mancia, Susana; Diaz-Ruiz, Araceli; Tristan-Lopez, Luis; Rios, Camilo

2014-01-01

127

Plant copper chaperones.  

PubMed

Copper chaperones, soluble copper-binding proteins, are essential for ensuring proper distribution of copper to cellular compartments and to proteins requiring copper prosthetic groups. They are found in all eukaryotic organisms. Orthologues of the three copper chaperones characterized in yeast, ATX1, CCS and COX17, are present in Arabidopsis thaliana. Plants are faced with unique challenges to maintain metal homoeostasis, and thus their copper chaperones have evolved by diversifying and gaining additional functions. In this paper we present our current knowledge of copper chaperones in A. thaliana based on the information available from the complete sequence of its genome. PMID:12196180

Wintz, H; Vulpe, C

2002-08-01

128

[Copper and copper alloys. Technology updates].  

PubMed

The correlations between copper and copper alloys and human health have been the subject of some recent and extensive scientific researches. The voluntary risks evaluation, which anticipated the EU REACH Directive application, has shown that copper is a "safe" product for human health and for environment. In addition, it could be of great help thanks to its antibacterial properties. Copper tube can contribute in a relevant way to the prevention of water systems pollution by Legionella. Also the spreading of nosocomial infections is significantly contrasted by the use of copper and copper alloys for the production of articles intended for being frequently touched by people. The Environmental Protection Agency of the United States has in fact "registered" as antibacterial over 350 of copper alloys. PMID:23213799

Loconsolo, V; Crespi, M

2012-01-01

129

Synthesis, crystal growth and characterization of phosphides, selenides, sulfides and oxides  

NASA Astrophysics Data System (ADS)

The desire to build smaller, faster, inexpensive electronics has prompted researchers to exploit electron "spin" in transistors. Spin in semiconductors offers a pathway towards integration of storage and processing in a single material. These "spintronic" transistors could be highly energy-efficient and perform more computations than traditional transistors in a smaller space. In addition, in optoelectronic applications, lasers and light-emitting diodes that take advantage of electron spin could increase the data-carrying capacity of light. But one of the key hurdles in this emerging field is that the magnetic and semiconducting materials needed to make a spintronic device are notoriously incompatible. We have focused on different oxides, phosphides and sulfides to study crystal growth and properties of spintronics. We have reported the synthesis of pure ZnO and Mn substituted ZnO crystals from sodium hydroxide and potassium hydroxide flux for the first time. Various oxides, including boron oxide (B2O3), vanadium oxide (V2O5), tungsten oxide (WO3) and molybdenum oxide (MoO3), were also used for crystal growth. A non-uniform distribution of Mn substitution was found in ZnO single crystals, and 3 at.% Mn concentration was identified. In addition, polycrystalline Mn-substituted ZnO powder samples exhibited solubility of Mn in the ZnO lattice. SQUID magnetic properties investigation of Mn-substituted polycrystalline samples indicated paramagnetism down to 5 K. We have also investigated phosphides, selenides, and sulfides for spintronic applications, based on the well-studied spintronic material, gallium arsenide (GaAs), with a Curie temperature of 110K. GaAs has the zincblende structure with Ga in tetrahedral coordination. ZnSiP2, CdSiP2, KGaS 2 and KGaSe2 have metal atoms in tetrahedral coordination with no localized spin. Localized spin will be present if transition metals are substituted in. The synthesis of single phase ZnSiP2 and CdSiP 2 were grown from two different heat treatments. Also, potassium gallium selenide (KGaSe2) and potassium gallium sulfide (KGaS2) were reported. Temperature dependence susceptibility data revealed a ferromagnetic transition near 300 K followed by an antiferromagnetic transition near 50 K. Hysteresis loops at room temperature were present in all Mn substituted samples. Magnetic properties of Mn substituted samples are comparable with the crystalline MnP sample; they remain unidentified in X-ray diffraction data.

Feng, Chun-Min

130

Topological insulator bismuth selenide as a theranostic platform for simultaneous cancer imaging and therapy  

NASA Astrophysics Data System (ADS)

Employing theranostic nanoparticles, which combine both therapeutic and diagnostic capabilities in one dose, has promise to propel the biomedical field toward personalized medicine. Here we investigate the theranostic properties of topological insulator bismuth selenide (Bi2Se3) in in vivo and in vitro system for the first time. We show that Bi2Se3 nanoplates can absorb near-infrared (NIR) laser light and effectively convert laser energy into heat. Such photothermal conversion property may be due to the unique physical properties of topological insulators. Furthermore, localized and irreversible photothermal ablation of tumors in the mouse model is successfully achieved by using Bi2Se3 nanoplates and NIR laser irradiation. In addition, we also demonstrate that Bi2Se3 nanoplates exhibit strong X-ray attenuation and can be utilized for enhanced X-ray computed tomography imaging of tumor tissue in vivo. This study highlights Bi2Se3 nanoplates could serve as a promising platform for cancer diagnosis and therapy.

Li, Juan; Jiang, Fei; Yang, Bo; Song, Xiao-Rong; Liu, Yan; Yang, Huang-Hao; Cao, Dai-Rong; Shi, Wen-Rong; Chen, Guo-Nan

2013-06-01

131

Topological insulator bismuth selenide as a theranostic platform for simultaneous cancer imaging and therapy.  

PubMed

Employing theranostic nanoparticles, which combine both therapeutic and diagnostic capabilities in one dose, has promise to propel the biomedical field toward personalized medicine. Here we investigate the theranostic properties of topological insulator bismuth selenide (Bi2Se3) in in vivo and in vitro system for the first time. We show that Bi2Se3 nanoplates can absorb near-infrared (NIR) laser light and effectively convert laser energy into heat. Such photothermal conversion property may be due to the unique physical properties of topological insulators. Furthermore, localized and irreversible photothermal ablation of tumors in the mouse model is successfully achieved by using Bi2Se3 nanoplates and NIR laser irradiation. In addition, we also demonstrate that Bi2Se3 nanoplates exhibit strong X-ray attenuation and can be utilized for enhanced X-ray computed tomography imaging of tumor tissue in vivo. This study highlights Bi2Se3 nanoplates could serve as a promising platform for cancer diagnosis and therapy. PMID:23770650

Li, Juan; Jiang, Fei; Yang, Bo; Song, Xiao-Rong; Liu, Yan; Yang, Huang-Hao; Cao, Dai-Rong; Shi, Wen-Rong; Chen, Guo-Nan

2013-01-01

132

Biokinetics and in vivo distribution behaviours of silica-coated cadmium selenide quantum dots.  

PubMed

Recently, quantum dots derived from trace elements like cadmium and selenium have attracted widespread interest in biology and medicine. They are rapidly being used as novel tools for both diagnostic and therapeutic purposes. In this report, we evaluated the distribution of silica-coated cadmium selenide (CdSe) quantum dots (QDs) following intravenous injection into male Swiss albino mice as a model system for determining tissue localization using in vivo fluorescence and ex vivo elemental analysis by inductively coupled plasma optical emission spectroscopy (ICP-OES). Trioctylphosphine oxide-capped CdSe quantum dots were synthesized and rendered water soluble by overcoating with silica, using aminopropyl silane (APS) as silica precursor. ICP-OES was used to measure the cadmium content to indicate the concentration of QDs in blood, organs and excretion samples collected at predetermined time intervals. Meanwhile, the distribution and aggregation state of QDs in tissues were also investigated in cryosections of the organs by fluorescence microscopy. We have demonstrated that the liver and kidney were the main target organs for QDs. Our systematic investigation clearly shows that most of the QDs were metabolized in the liver and excreted via faeces and urine in vivo. A fraction of free QDs, maintaining their original form, could be filtered by glomerular capillaries and excreted via urine as small molecules within 5 days. PMID:20645133

Vibin, M; Vinayakan, R; John, Annie; Raji, V; Rejiya, C S; Abraham, Annie

2011-08-01

133

Elongated Hoop Structures in Quasi-1D Tantalum Di-Selenide Crystals  

NASA Astrophysics Data System (ADS)

Several novel topological crystal structures were discovered when performing scanning electron microscopy upon quasi-1D tantalum di-selenide crystals. The sample was comprised of mostly strand-like fibers with chemical compositions ranging from TaSe2 to TaSe3. These were randomly oriented as to create a macroscopic view akin to a matted nest. Upon further investigation of the sample, hoops and elongated hoop structures were discovered. The single hoops appeared to be comprised of a single strand connected at both ends. The elongated hoops most closely resembled spools of thread. The single hoops were most likely formed when a strand wrapped around a ball of liquid selenium during the formation of the crystals, as first discovered by Satoshsi Tanda of Hokkaido University. However, this theory does not adequately explain the formation of the elongated hoop structures, which have cylindrical interiors. These structures could be categorized in two different ways. Some were tightly wrapped much like a spool of thread while several resembled a slightly compressed spring. Currently, no clear theory has been developed for their creation, although we suspect inhomogeneities in the chemical stoichiometry to play a leading role.

Beck, Ben

2011-11-01

134

Synthesis and characterization of a new quaternary selenide Sr 3GeSb 2Se 8  

NASA Astrophysics Data System (ADS)

A new quaternary selenide Sr 3GeSb 2Se 8 has been synthesized at 750 °C from pure elements in a stoichiometric ratio under vacuum. The product as-synthesized is characterized by single-crystal X-ray diffraction, diffuse reflectance spectroscopy, and thermoanalysis. The title compound crystallizes in the orthorhombic space group Pnma with a = 12.633(4) Å, b = 4.301(1) Å, c = 28.693(7) Å, V = 1558.8(8) Å 3, Z = 4, R1/ wR2 = 0.0582/0.1221, and GOF = 1.077. The structure of Sr 3GeSb 2Se 8 features a new structural type that consists of one-dimensional chains of vertex-sharing tetrahedra [MSe]?1 (M = Ge/Sb) and fused double chains of edge-shared square pyramids [MSe]?1, which are held together by Sr 2+ ions. A band gap of 0.75 eV for Sr 3GeSb 2Se 8 was derived from its diffuse reflectance spectrum.

Yu, Ching-Yi; Wang, Ming-Fang; Chung, Ming-Yang; Jang, Shyue-Ming; Huang, Jih-Chen; Lee, Chi-Shen

2008-09-01

135

Transition-metal doped sulfide, selenide, and telluride laser crystal and lasers  

DOEpatents

A new class of solid state laser crystals and lasers are formed of transition metal doped sulfide, selenide, and telluride host crystals which have four fold coordinated substitutional sites. The host crystals include II-VI compounds. The host crystal is doped with a transition metal laser ion, e.g., chromium, cobalt or iron. In particular, Cr.sup.2+ -doped ZnS and ZnSe generate laser action near 2.3 .mu.m. Oxide, chloride, fluoride, bromide and iodide crystals with similar structures can also be used. Important aspects of these laser materials are the tetrahedral site symmetry of the host crystal, low excited state absorption losses and high luminescence efficiency, and the d.sup.4 and d.sup.6 electronic configurations of the transition metal ions. The same materials are also useful as saturable absorbers for passive Q-switching applications. The laser materials can be used as gain media in amplifiers and oscillators; these gain media can be incorporated into waveguides and semiconductor lasers.

Krupke, William F. (Pleasanton, CA); Page, Ralph H. (San Ramon, CA); DeLoach, Laura D. (Manteca, CA); Payne, Stephen A. (Castro Valley, CA)

1996-01-01

136

Size-induced effects in gallium selenide electronic structure: The influence of interlayer interactions  

NASA Astrophysics Data System (ADS)

The electronic structure of two-dimensional gallium selenide crystals containing a small number of layers was investigated theoretically and experimentally. The electronic band structure of the layered GaSe crystal was investigated by the first-principles density functional theory calculations. The GW approximation was used for the correction of the band-gap values. A dependence of the band-gap value on the number of tetralayers has been demonstrated. For the thin crystal with several tetralayers, the band gap becomes larger compared to the bulk crystal. The thin layers of GaSe have been experimentally produced by the ultrasonication of GaSe particles in water suspensions in the presence of Pluronic F127 surfactant. Their thickness was from one to a few tetralayers, according to the transmission electron microscopy studies. The optical absorption spectra demonstrate the well-resolved bands, shifted toward the blue relative to those of the bulk GaSe. Their origin is caused by the presence of GaSe structures with one to a few tetralayers.

Rybkovskiy, D. V.; Arutyunyan, N. R.; Orekhov, A. S.; Gromchenko, I. A.; Vorobiev, I. V.; Osadchy, A. V.; Salaev, E. Yu.; Baykara, T. K.; Allakhverdiev, K. R.; Obraztsova, E. D.

2011-08-01

137

Spectroscopic ellipsometry of self assembled monolayers: interface effects. The case of phenyl selenide SAMs on gold.  

PubMed

This work focuses on the quantitative application of spectroscopic ellipsometry to the study of optical properties and thickness of self assembled monolayers (SAMs) of phenyl selenide deposited from the liquid phase on gold. STM, XPS and cyclic voltammetry measurements provide additional chemical and morphological characterization of the SAMs. While routine ellipsometry analysis of SAMs often relies on the film-induced ?? change in the ? ellipsometric angle and discards SAM-substrate interface effects, the present data show a distinctive behaviour of the ?? data that we assign to interface effects, stronger than those previously found for densely packed alkanethiol SAMs. An inaccurate modelling of the variations in ? related to the nano-structured SAM-substrate interface leads to a large overestimation of the film thickness. A simple model, which takes into account an effective approximation for the interface layer between the film and the substrate, and the molecular optical absorptions, provides a good agreement between the data and a reliable thickness estimate of the SAM. PMID:23752814

Canepa, Maurizio; Maidecchi, Giulia; Toccafondi, Chiara; Cavalleri, Ornella; Prato, Mirko; Chaudhari, Vijay; Esaulov, Vladimir A

2013-07-21

138

Transition-metal doped sulfide, selenide, and telluride laser crystal and lasers  

DOEpatents

A new class of solid state laser crystals and lasers are formed of transition metal doped sulfide, selenide, and telluride host crystals which have four fold coordinated substitutional sites. The host crystals include II-VI compounds. The host crystal is doped with a transition metal laser ion, e.g., chromium, cobalt or iron. In particular, Cr{sup 2+}-doped ZnS and ZnSe generate laser action near 2.3 {micro}m. Oxide, chloride, fluoride, bromide and iodide crystals with similar structures can also be used. Important aspects of these laser materials are the tetrahedral site symmetry of the host crystal, low excited state absorption losses and high luminescence efficiency, and the d{sup 4} and d{sup 6} electronic configurations of the transition metal ions. The same materials are also useful as saturable absorbers for passive Q-switching applications. The laser materials can be used as gain media in amplifiers and oscillators; these gain media can be incorporated into waveguides and semiconductor lasers. 18 figs.

Krupke, W.F.; Page, R.H.; DeLoach, L.D.; Payne, S.A.

1996-07-30

139

Solution Assembly of Hybrid Poly (3-hexyl thiophene) and Cadmium Selenide Nanowires  

NASA Astrophysics Data System (ADS)

Optimizing morphology of self-assembled systems containing both electron carrying (n-type) and hole carrying (p-type) materials holds promise for the fabrication of improved devices, such as solar cells. In this talk, two routes to formation of hybrid p-n composite fibrils consisting of crystalline p-type poly(3-hexyl thiophene) (P3HT) nanowires with n-type cadmium selenide (CdSe) quantum dots and nanorods into well-defined structures will be discussed. The first method involves co-crystallization of freely soluble P3HT and P3HT-functionalized CdSe nanorods to form crystalline hybrid nanowires upon addition of a marginal solvent. Transmission electron microscopy reveals that nanorods preferentially orient parallel to and flank the sides of fibers. In a second route to forming hybrid materials, chain-end functionalized P3HT is crystallized into fibrillar nanowires. Introduction of nanoparticles promotes binding at the fibril edge, forming parallel composite pathways or ``superhighways.'' These assembly approaches represent efficient means to organization of conjugated polymers and semiconducting nanostructures, thus offering new opportunities for optoelectronic device design.

Bokel, Felicia; Pentzer, Emily; Emrick, Todd; Hayward, Ryan

2012-02-01

140

Patterning of cadmium selenide quantum dot nanocrystals for use with photovoltaic applications  

NASA Astrophysics Data System (ADS)

In this thesis, cadmium selenide (CdSe) quantum dots (QDs) are synthesized and characterized for patterning applications as well as for photovoltaic devices. The QDs were patterned and embedded into various polymers to form fluorescent composites. Their photophysical properties were investigated in detail. Through template assisted deposition the QDs-polymer composites were patterned into fluorescent nanorods. CdSe QDs were combined with multi-wall carbon nanotubes (CNTs) using a synthesized organic perylene derivative dye (N,N'-di(ethanethiol)-perylene-3,4,9,10-tetracarboxyl diimide) (ETPTCDI) as a link between QDs and CNTs. Upon testing, the QDs-ETPTCDI-CNTs nanocomposite displayed photoactive properties. Photophysical quenching studies of QD-ETPTCDI-CNTs provided better understanding of the electron-hole transfer of each component in the nanocomposite. The nanocomposite material was patterned onto microelectrode devices for photocurrent measurements under an AM1.5 solar simulated light source. These nanocomposites can be used as photovoltaic devices. The preliminary characterization studies of the device show excellent photoresponse under AM1.5 solar simulated light. The band gap alignment of each component of the nanocomposite and the charge transfer kinetics are the key to efficient electron-hole transfer. Optimization of the semiconducting material's interface can potentially make these nanocomposites a system for photovoltaic-based devices.

Weaver, Joseph Edison

141

Efficient solution-processed small molecule: Cadmium selenide quantum dot bulk heterojunction solar cells  

NASA Astrophysics Data System (ADS)

We report bulk heterojunction solar cells based on blends of solution-processed small molecule [7,7'-(4,4-bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b']dithiophene-2,6-diyl)bis(6-fluoro-4-(5'-hexyl-[2,2'-bithiophen]-5yl)benzo[c] [1,2,5] thiadiazole)] p-DTS(FBTTh2)2: Cadmium Selenide (CdSe) (70:30, 60:40, 50:50, and 40:60) in the device configuration: Indium Tin Oxide /poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/p-DTS(FBTTh2)2: CdSe/Ca/Al. The optimized ratio of p-DTS(FBTTh2)2:CdSe::60:40 leads to a short circuit current density (Jsc) = 5.45 mA/cm2, open circuit voltage (Voc) = 0.727 V, and fill factor (FF) = 51%, and a power conversion efficiency = 2.02% at 100 mW/cm2 under AM1.5G illumination. The Jsc and FF are sensitive to the ratio of p-DTS(FBTTh2)2:CdSe, which is a crucial factor for the device performance.

Gupta, Vinay; Upreti, Tanvi; Chand, Suresh

2013-12-01

142

Chemical deposition of bismuth selenide thin films using N,N-dimethylselenourea  

NASA Astrophysics Data System (ADS)

Good quality thin films of bismuth selenide of thickness up to 0268-1242/12/5/020/img7 were deposited from solutions containing bismuth nitrate, triethanolamine and N,N-dimethylselenourea maintained at temperatures ranging from room temperature to 0268-1242/12/5/020/img8. X-ray diffraction patterns of the samples annealed at 0268-1242/12/5/020/img9 in air match the standard pattern of hexagonal 0268-1242/12/5/020/img10 (paraguanajuatite, JCPDS 33-0214). The films exhibit strong optical absorption corresponding to a bandgap of about 1.7 - 1.41 eV in the as-prepared films. These values decrease to about 1.57 - 1.06 eV upon annealing the films at 0268-1242/12/5/020/img9 for 1 h in nitrogen. As-deposited, the films show high sheet resistance 0268-1242/12/5/020/img12 in the dark. Annealing the films in air or in nitrogen enhances the dark current by about seven orders of magnitude; the resulting dark conductivity is about 0268-1242/12/5/020/img13. This enhancement in conductivity results from improved crystallinity as well as from partial loss of selenium.

García, V. M.; Nair, M. T. S.; Nair, P. K.; Zingaro, R. A.

1997-05-01

143

Bond thermal expansion and effective pair potential in crystals: the case of cadmium selenide  

NASA Astrophysics Data System (ADS)

The local dynamics of cadmium selenide (CdSe) with wurtzite structure has been investigated by molecular dynamics simulations, using a many-body Tersoff potential. The radial distribution functions (i.e., the effective pair potentials) of the first seven coordination shells have been determined as a function of temperature, as well as their parallel and perpendicular mean-square relative atomic displacements. The bond thermal expansion of the first coordination shell is mainly due to the asymmetry of the effective pair potential. In contrast, the bond thermal expansion of the outer shells is mostly due to a rigid shift of the effective pair potential. This behavior, recently observed also in simple cubic monoatomic crystals, can be generalized and related to the correlation of atomic motion. Finally, a shift toward lower values of the first Se-Cd effective pair potential has been observed when increasing the temperature, confirming previous findings by extended x-ray absorption fine-structure measurements. Differently from superionic conductors like AgI and CuBr, in which this anomalous negative shift was tentatively explained by cluster distortion and cation diffusion, the negative shift of CdSe is related to the peculiar properties of the crystalline potential.

Sanson, Andrea

2011-08-01

144

Development of bismuth tellurium selenide nanoparticles for thermoelectric applications via a chemical synthetic process  

SciTech Connect

Research highlights: {yields} We synthesized a Bi{sub 2}Te{sub y}Se{sub 3-y} nano-compound via a chemical synthetic process. {yields} The compound was sintered to achieve an average grain size of about 300 nm. {yields} The resulting sintered body showed very low thermal conductivity. It is likely caused by the vigorous phonon scattering of the nano-sized grains. -- Abstract: Bismuth tellurium selenide (Bi{sub 2}Te{sub y}Se{sub 3-y}) nanoparticles for thermoelectric applications are successfully prepared via a water-based chemical reaction under atmospheric conditions. The nanostructured compound is prepared using a complexing agent (ethylenediaminetetraacetic acid) and a reducing agent (ascorbic acid) to stabilize the bismuth precursor (Bi(NO{sub 3}){sub 3}) in water and to favor the reaction with reduced sources of tellurium and selenium. The resulting powder is smaller than ca. 100 nm and has a crystalline structure corresponding to the rhombohedral Bi{sub 2}Te{sub 2.7}Se{sub 0.3}. The nanocrystalline powder is sintered via a spark plasma sintering process to obtain a sintered body composed of nano-sized grains. Important transport properties of the sintered body are measured to calculate its most important characteristic, the thermoelectric performance. The results demonstrate a relationship between the nanostructure of the sintered body and its thermal conductivity.

Kim, Cham [Daegu Gyeongbuk Institute of Science and Technology (DGIST), 711-623 Hosan-dong, Dalseo-gu, Daegu 704-230 (Korea, Republic of) [Daegu Gyeongbuk Institute of Science and Technology (DGIST), 711-623 Hosan-dong, Dalseo-gu, Daegu 704-230 (Korea, Republic of); Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), San 31 Hyoja-dong, Pohang 790-784 (Korea, Republic of); Kim, Dong Hwan; Han, Yoon Soo [Daegu Gyeongbuk Institute of Science and Technology (DGIST), 711-623 Hosan-dong, Dalseo-gu, Daegu 704-230 (Korea, Republic of)] [Daegu Gyeongbuk Institute of Science and Technology (DGIST), 711-623 Hosan-dong, Dalseo-gu, Daegu 704-230 (Korea, Republic of); Chung, Jong Shik [Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), San 31 Hyoja-dong, Pohang 790-784 (Korea, Republic of)] [Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), San 31 Hyoja-dong, Pohang 790-784 (Korea, Republic of); Park, SangHa [Daegu Machinery Institute of Components and Materials (DMI), 12 Horim-dong, Dalseo-gu, Daegu 704-240 (Korea, Republic of)] [Daegu Machinery Institute of Components and Materials (DMI), 12 Horim-dong, Dalseo-gu, Daegu 704-240 (Korea, Republic of); Park, Soonheum [Department of Nanomaterial Chemistry, Dongguk University, Seokjang-dong, Gyeongju, Gyeongbuk 780-714 (Korea, Republic of)] [Department of Nanomaterial Chemistry, Dongguk University, Seokjang-dong, Gyeongju, Gyeongbuk 780-714 (Korea, Republic of); Kim, Hoyoung, E-mail: hoykim@dgist.ac.kr [Daegu Gyeongbuk Institute of Science and Technology (DGIST), 711-623 Hosan-dong, Dalseo-gu, Daegu 704-230 (Korea, Republic of)] [Daegu Gyeongbuk Institute of Science and Technology (DGIST), 711-623 Hosan-dong, Dalseo-gu, Daegu 704-230 (Korea, Republic of)

2011-03-15

145

Copper-phosphorus alloys offer advantages in brazing copper  

Microsoft Academic Search

Copper-phosphorus brazing alloys are used extensively for joining copper, especially refrigeration and air-conditioning copper tubing and electrical conductors. What is the effect of phosphorus when alloyed with copper? The following are some of the major effects: (1) It lowers the melt temperature of copper (a temperature depressant). (2) It increases the fluidity of the copper when in the liquid state.

1996-01-01

146

Copper Doped Polycrystalline Silicon.  

National Technical Information Service (NTIS)

It was discovered, in accordance with the invention, that the presence of copper in polycrystalline silicon solar cells strongly enhances the performance of the cells. It was further discovered that the effect of copper in polycrystalline, silicon solar c...

K. M. Koliwad T. Daud

1979-01-01

147

Copper Crusher Gauge Holder.  

National Technical Information Service (NTIS)

A copper crusher gauge holder for testing internal pressures of cartridges during test firing is provided. The copper crusher gauge holder has a circular aluminum upper plate and a circular aluminum lower plate having a layer of urethane rubber approximat...

E. W. Bowie R. E. Bowen

1997-01-01

148

Synthesis, structures and DFT calculations of 2-(4,6-dimethyl pyrimidyl)selenolate complexes of Cu(I), Ag(I) and Au(I) and their conversion into metal selenide nanocrystals.  

PubMed

The complexes [M{SeC4H(Me-4,6)2N2}]6 (M = Cu (1), Ag (2)) and [Au{SeC4H(Me-4,6)2N2}(PEt3)] (3) have been prepared and characterized by elemental analyses, UV-vis, NMR ((1)H, (13)C, (77)Se) spectroscopy and single crystal X-ray diffraction. The crystal structures of [Cu{SeC4H(Me-4,6)2N2}]6·H2O (1·H2O), [Ag{SeC4H(Me-4,6)2N2}]6·6MeOH·H2O (2·6MeOH·H2O) and [Au{SeC4H(Me-4,6)2N2}(PEt3)] (3) revealed that their metal centers acquire distorted square-pyramidal, trigonal and linear geometries, respectively. DFT calculations have been carried out to rationalize nuclearity in copper(i) chalcogenolate complexes. The calculations suggest that there is hardly any energy difference between the tetrameric and hexameric forms. Thermal behavior of [Cu{SeC4H(Me-4,6)2N2}]6 was studied by thermogravimetric analysis. Thermolysis of [M{SeC4H(Me-4,6)2N2}]6 (M = Cu, Ag) in 1-dodecanethiol (DDT) at 150 °C gave a cubic phase of Cu7Se4 and an orthorhombic phase of Ag2Se, respectively. Copper selenide (Cu7Se4) thin films were deposited on glass and silicon substrates by using [Cu{SeC4H(Me-4,6)2N2}]6 at 400 °C by AACVD. PMID:24623060

Sharma, Rakesh K; Wadawale, Amey; Kedarnath, G; Manna, Debashree; Ghanty, Tapan K; Vishwanadh, B; Jain, Vimal K

2014-05-01

149

Separation of Copper-64 from Copper Phthalocyanine.  

National Technical Information Service (NTIS)

The separation of copper-64 from irradiated copper phthalocyanine by Szilard-Chalmers effect is studied. Two methods of separation are used: one of them is based on the dissolution of the irradiated dry compound in concentrated sulfuric acid following its...

R. I. M. Battaglin

1979-01-01

150

Laser induced copper plating  

Microsoft Academic Search

Argon laser induced plating of copper spots and lines from copper sulfate solutions on glass and phenolic resin paper has been investigated. The substrates had to be precoated with an evaporated copper film. The highest plating rates have been obtained with a small film thickness of 25 nm. Spots with a thickness up to 30 ?m were plated.

A. K. Al-Sufi; H. J. Eichler; J. Salk; H. J. Riedel

1983-01-01

151

On copper peroxide  

NASA Technical Reports Server (NTRS)

The action of hydrogen superoxide on copper salts in alcoholic solutions is studied. The action of hydrogen peroxide on copper hydroxide in alcoholic suspensions, and the action of ethereal hydrogen peroxide on copper hydroxide are discussed. It is concluded that using the procedure proposed excludes almost entirely the harmful effect of hydrolysis.

Moser, L.

1988-01-01

152

Copper: Technology & Standards  

NSDL National Science Digital Library

This article explains modern copper mining, ore extraction, and casting processes and details innovative copper products, major markets, service activities, and the future of copper in industry and everyday life. It was published in the November 1998 issue of the online magazine Innovations.

Cohen, Art; Association, Copper D.

153

Vacancies Ordered in Screw Form (VOSF) and Layered Indium Selenide Thin Film Deposition by Laser Back Ablation  

SciTech Connect

Indium selenide thin films are important due to their applications in non-volatile memory and solar cells. In this work, we present an initial study of a new application of deposition-site selective laser back ablation (LBA) for making thin films of In2Se3. In-vacuo annealing and subsequent characterization of the films by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) indicate that control of substrate temperature during deposition and post-deposition annealing temperature is critical in determining the phase and composition of the films. The initial laser fluence and target film thickness determine the amount of material deposited onto the substrate.

Beck, Kenneth M.; Wiley, William R.; Venkatasubramanian, Eswaranand; Ohuchi, Fumio S.

2009-09-30

154

Surface and bulk absorption characteristics of chemically vapor-deposited zinc selenide in the infrared.  

PubMed

Chemically vapor-deposited zinc selenide exhibits outstanding properties in the infrared and has been established as a prime material for transmissive optics applications. Here we present and discuss data relating to the surface and the bulk absorption forward-looking infrared- (FLIR-) grade chemically vapor-deposited ZnSe, at wavelengths (2-20 µm) and temperatures (100-500 K) of current interest.

This investigation is based on both spectral emittance measurements and infrared transmission spectroscopy performed in the context of a systems development program. Surface effects can be detected at wavelengths of up to 14 µm and usually predominate at wavelengths of less than 8 µm. Fractional surface absorptions are temperature independent from approximately 200 to 400 K and can be fitted to a Fourier series, at wavelengths ranging from 3.5 to 13.5 µm. The bulk absorption coefficient (?v) is strongly dependent on temperature as well as wavelength, but it can be approximated by a bivariate polynomial expressin that yields recommended values. At wavelengths ? ? 10 µm, ?v decreases with increasing temperature; it is shown that a wavelength-independent Debye-Waller factor provides a correct description of the temperature dependence, thus pointing to infrared-active localized modes. At wavelengths ? ? 14 µm, ?v increases with temperature and exhibits temperature dependencies (T(1.7), T(2.6)) that reflect three- and four-phonon summation processes. Finally, an analysis of the temperature dependence of ?v at 10.6 µm demonstrates that the intrinsic lattice dynamical contribution to bulk absorption at this wavelength should be close to 4 × 10(-4) cm(-1), in accord with the results of earlier laser calorimetry tests performed on exceptionally pure laser-grade chemically vapor-deposited ZnSe.

PMID:20935788

Klein, C A; Miller, R P; Stierwalt, D L

1994-07-01

155

Ultrafast exciton dynamics in cadmium selenide nanocrystals determined by femtosecond fluorescence upconversion spectroscopy  

NASA Astrophysics Data System (ADS)

Femtosecond fluorescence upconversion spectroscopy is a technique that allows the unambiguous determination of the excited state dynamics of an analyte. Combining this method with the use of tunable laser excitation, the exciton dynamics in semiconducting nanocrystals (NC's) of cadmium selenide (CdSe) have been determined, devoid of the complications arising from more common spectroscopic methods such as pump-probe. The results of this investigation were used to construct a model to fully describe the three-level system comprising of the valence and conduction bands and surface states, which have been calculated by others to lie mid-gap in energy. Smaller NC's showed faster decay components due to increased interaction between the exciton and surface states. The deep trap emission, which has never before been measured by ultrafast fluorescence techniques, shows a rapid rise time (˜2 ps), which is attributed to surface selenium dangling bonds relaxing to the valence band and radiatively combining with the photo-generated hole. The band edge fluorescence decays as the deep trap emission grows in, inherently coupling the two processes. An experiment which measured the dependence of the excitation energy showed that increased energy imparted to the NC's resulted in increased rise times, yielding the timescales for exciton relaxation through the valence and conduction band states to the lowest emitting state. Surface-oxidized and normally-passivated NC's display the same decay dynamics in time but differ in relative amplitude; the latter point agrees with steady-state measurements. The rotational anisotrophy of the NC's was measured and agrees with previous pump-probe data. Upconversion on the red and blue sides of the static fluorescence spectrum showed no discernable differences, which is either and inherent limitation of the experimental apparatus, or the possibility that lower-lying triplet states are populated on a timescale below the instrument resolution.

Underwood, David Frederick

156

Parallel molecular dynamics simulations of pressure-induced structural transformations in cadmium selenide nanocrystals  

NASA Astrophysics Data System (ADS)

Parallel molecular dynamics (MD) simulations are performed to investigate pressure-induced solid-to-solid structural phase transformations in cadmium selenide (CdSe) nanorods. The effects of the size and shape of nanorods on different aspects of structural phase transformations are studied. Simulations are based on interatomic potentials validated extensively by experiments. Simulations range from 105 to 106 atoms. These simulations are enabled by highly scalable algorithms executed on massively parallel Beowulf computing architectures. Pressure-induced structural transformations are studied using a hydrostatic pressure medium simulated by atoms interacting via Lennard-Jones potential. Four single-crystal CdSe nanorods, each 44A in diameter but varying in length, in the range between 44A and 600A, are studied independently in two sets of simulations. The first simulation is the downstroke simulation, where each rod is embedded in the pressure medium and subjected to increasing pressure during which it undergoes a forward transformation from a 4-fold coordinated wurtzite (WZ) crystal structure to a 6-fold coordinated rocksalt (RS) crystal structure. In the second so-called upstroke simulation, the pressure on the rods is decreased and a reverse transformation from 6-fold RS to a 4-fold coordinated phase is observed. The transformation pressure in the forward transformation depends on the nanorod size, with longer rods transforming at lower pressures close to the bulk transformation pressure. Spatially-resolved structural analyses, including pair-distributions, atomic-coordinations and bond-angle distributions, indicate nucleation begins at the surface of nanorods and spreads inward. The transformation results in a single RS domain, in agreement with experiments. The microscopic mechanism for transformation is observed to be the same as for bulk CdSe. A nanorod size dependency is also found in reverse structural transformations, with longer nanorods transforming more readily than smaller ones. Nucleation initiates at the center of the rod and grows outward.

Lee, Nicholas Jabari Ouma

157

Structural and topological control on physical properties of arsenic selenide glasses.  

PubMed

The structures of Ge-doped arsenic selenide glasses with Se contents varying between 25 and 90 at. % are studied using a combination of high-resolution, two-dimensional (77)Se nuclear magnetic resonance (NMR) and Raman spectroscopy. The results indicate that, in contrast to the conventional wisdom, the compositional evolution of the structural connectivity in Se-excess glasses does not follow the chain-crossing model, and chemical order is likely violated with the formation of a small but significant fraction of As-As bonds. The addition of As to Se results in a nearly random cross-linking of Se chains by AsSe3 pyramids, and a highly chemically ordered network consisting primarily of corner-shared AsSe3 pyramids is formed at the stoichiometric composition. Further increase in As content, up to 40 at. % Se, results in the formation of a significant fraction of As4Se3 molecules with As-As homopolar bonds, and consequently the connectivity and packing efficiency of the network decrease and anharmonic interactions increase. Finally, in the highly As-rich region with <40 at. % Se, the relative concentration of the As4Se3 molecules decreases rapidly and large clusters of As atoms connected via Se-Se-As and As-Se-As linkages dominate. These three composition regions with distinct structural characteristics and the corresponding mixing entropy of the Se environments are reflected in the appearance of multiple extrema in the compositional variation of a wide range of physical properties of these glasses, including density, glass transition temperature, thermal expansivity, and fragility. PMID:24490990

Kaseman, Derrick C; Hung, Ivan; Gan, Zhehong; Aitken, Bruce; Currie, Steven; Sen, Sabyasachi

2014-02-27

158

First principles study of electronic and mechanical properties of molybdenum selenide type nanowires  

NASA Astrophysics Data System (ADS)

Using the first-principles plane-wave pseudopotential method within density functional theory, we have systematically investigated structural, electronic, and mechanical properties of M2Y6X6 , Y6X6 ( X=Se,Te,S ; Y=Mo,Cr,W ; and M=Li,Na ) nanowires and bulk phase of M2Y6X6 . We found that not only Mo6X6 , but also transition metal and chalcogen atoms lying in the same columns of Mo and Se can form stable nanowires consisting of staggered triangles of Y3X3 . We have shown that all wires have nonmagnetic ground states in their equilibrium geometry. Furthermore, these structures can be either a metal or semiconductor depending on the type of chalcogen element. All Y6X6 wires with X=Te atom are semiconductors. Mechanical stability, elastic stiffness constants, breaking point, and breaking force of these wires have been calculated in order to investigate the strength of these wires. Ab initio molecular dynamic simulations performed at 500K suggest that overall structure remains unchanged at high temperature. Adsorption of H, O, and transition metal atoms like Cr and Ti on Mo6Se6 have been investigated for possible functionalization. All these elements interact with Mo6Se6 wire forming strong chemisorption bonds, and a permanent magnetic moment is induced upon the adsorption of Cr or Ti atoms. Molybdenum selenide-type nanowires can be alternative for carbon nanotubes, since the crystalline ropes consisting of one type of (M2)Y6X6 structures can be decomposed into individual nanowires by using solvents, and an individual nanowire by itself is either a metal or semiconductor and can be functionalized.

Çak?r, D.; Durgun, E.; Gülseren, O.; Ciraci, S.

2006-12-01

159

Reduction of selenate to selenide by sulfate-respiring bacteria: Experiments with cell suspensions and estuarine sediments  

USGS Publications Warehouse

Washed cell suspension of Desulfovibrio desulfuricans subsp. aestuarii were capable of reducing nanomolar levels of selenate to selenide as well as sulfate to sulfide. Reduction of these species was inhibited by 1 mM selenate or tungstate. The addition of 1 mM sulfate decreased the reduction of selenate and enhanced the reduction of sulfate. Increasing concentrations of sulfate inhibited rates of selenate reduction but enhanced sulfate reduction rates. Cell suspensions kept in 1 mM selenate were incapable of reducing either selenate or sulfate when the selenate/sulfate ratio was ???0.02, indicating that irreversible inhibition occurs at high selenate concentrations. Anoxic estuarine sediments having an active flora of sulfate-respiring bacteria were capable of a small amount of selenate reduction when ambient sulfate concentrations were low (<4 mM). These results indicate that sulfate is an inhibitor of the reduction of trace qunatitites of selenate. Therefore, direct reduction of traces of selenate to selenide by sulfate-respiring bacteria in natural environments is constrained by the ambient concentration of sulfate ions. The significance of this observation with regard to the role sediments play in sequestering selenium is discussed.

Zehr, J. P.; Oremland, R. S.

1987-01-01

160

Growth and evaluation of nonlinear optical crystals for laser applications: Lithium borate, barium borate and silver gallium selenide  

NASA Astrophysics Data System (ADS)

This report summarizes a four year program on the development of high efficiency nonlinear optical materials. Major achievements were the development of effective top-seeded solution growth techniques for beta-barium borate (BBO) and lithium triborate (LBO). BBO crystals were also grown for the first time in the US by the direct melt growth technique, a metastable method that leads to significantly higher growth rates than the commercial solution-growth technique. High quality crystals were made available for optical property determinations and nonlinear optical device development at government and commercial laboratories. Additional accomplishments involved development of an optimum heat-treatment technology for eliminating optical scattering centers from as-grown crystals of silver gallium selenide. Cooperative programs were carried out with NRL to quantify the effects of intrinsic and extrinsic defects on residual absorption. It was discovered that silver gallium selenide and silver gallium sulfide crystals grown from silver-rich solutions are free of anomolous absorption in the 2 micron waveband which is currently the major problem limiting generation of high intensity, tunable 3-5 micron radiation by OPO methods using these materials. A new nonlinear optical material, (La,Gd)Sc3(BO3)4 has been identified for future study.

Feigelson, Robert S.; Route, Roger K.

1994-12-01

161

A surface and interface study of aluminum selenide on silicon: Growth and characterization of thin films  

NASA Astrophysics Data System (ADS)

The first growth of aluminum selenide on silicon is reported. A thin AlSe layer was formed on Si(111) by molecular beam epitaxy from a stoichiometric Al2Se3 evaporative source. The structural and electronic properties of the interface were investigated using angle-resolved valence and core-level photoelectron spectroscopy and diffraction. The AlSe-Si interface forms a bilayer structure similar to GaSe-terminated Si, however, the temperatures for bilayer formation and for Se re-evaporation from the film are higher for AlSe than for GaSe. In addition, the valence band structure shows that the AlSe bilayer termination electronically passivates the bulk Si with all interface states within the bulk Si bands. The passivated nature of the AlSe-terminated Si(11) surface make this a good candidate substrate for growth of quantum dots or other heteroepitaxy. To test their chemical stability, AlSe-terminated Si(111) and GaSe-terminated Si(111) have been exposed to a variety of atmospheric constituents. The resulting surfaces were investigated by photoelectron spectroscopy to examine changes, if any, in the local chemical environment of atomic constituents. The GaSe-terminated Si substrates were largely unaffected by the exposures, and physisorbed contaminants were easily removed by mild annealing. AlSe-terminated Si reacted with both pure O2 and atmosphere, and the clean bilayer surface was not recoverable. The differences in chemical stability show that GaSe would be more suitable than AlSe as a substrate for further heteroepitaxy (e.g. quantum dot formation) under a wide range of growth conditions; despite having lower temperature stability. We have also produced epitaxial thin films of Al2Se3 on Si(111). Higher flux rates of Al2Se3 are necessary to grow Al2Se3 bulk films on silicon than to form the interface bilayer. Photoemission spectroscopy was used to examine films of graded thickness, and the evolution of chemical environment and electronic structure with increasing film thickness was observed. Intermediate-thickness film characteristics are compared to those of the bilayer interface and of bulk Al2Se3. Also, we have measured the valence electronic structure of "thick" thin films of Al2Se3 grown on Si(111). With increasing thickness above the interface bilayer, the thin films show rapid development of bulk-like features, including the 3x3 vacancy ordering.

Adams, Jonathan A.

162

Biogenic nanoparticles: copper, copper oxides, copper sulphides, complex copper nanostructures and their applications.  

PubMed

Copper nanoparticles have been the focus of intensive study due to their potential applications in diverse fields including biomedicine, electronics, and optics. Copper-based nanostructured materials have been used in conductive films, lubrification, nanofluids, catalysis, and also as potent antimicrobial agent. The biogenic synthesis of metallic nanostructured nanoparticles is considered to be a green and eco-friendly technology since neither harmful chemicals nor high temperatures are involved in the process. The present review discusses the synthesis of copper nanostructured nanoparticles by bacteria, fungi, and plant extracts, showing that biogenic synthesis is an economically feasible, simple and non-polluting process. Applications for biogenic copper nanoparticles are also discussed. PMID:23690046

Rubilar, Olga; Rai, Mahendra; Tortella, Gonzalo; Diez, Maria Cristina; Seabra, Amedea B; Durán, Nelson

2013-09-01

163

Copper Delivery by Metallochaperone Proteins  

SciTech Connect

Copper is an essential element in all living organisms, serving as a cofactor for many important proteins and enzymes. Metallochaperone proteins deliver copper ions to specific physiological partners by direct protein-protein interactions. The Atx1-like chaperones transfer copper to intracellular copper transporters, and the CCS chaperones shuttle copper to copper,zinc superoxide dismutase. Crystallographic studies of these two copper chaperone families have provided insights into metal binding and target recognition by metallochaperones and have led to detailed molecular models for the copper transfer mechanism.

Rosenzweig, A.C. (NWU)

2010-03-08

164

Neche H. I. Ksheminska H. P. Kolisnyk H. V. al. (2009) Reduction chromate carton-synthesizing activity selenide -resistant mutant yeast Xanthophyllomyces dendrorhous (Pavia rhodozyma). people. Cell 25(4):  

EPA Pesticide Factsheets

Did you mean Neche H. I. Ksheminska H. P. Kolisnyk H. V. al. (2009) Reduction chromate carton-synthesizing activity selenide -resistant mutant yeast Xanthophyllomyces dendrorhous (Pavia rhodozyma). people. Cell 25(4): ?

165

Frequency Doubling of 10.6 Micrometer Radiation from a Tea Laser in Polycrystalline Zinc Selenide Frekvensfoerdubbling AV 10.6 Micrometer Stralning Fran en Tea-Laser I Polykristallin Zinkselenid.  

National Technical Information Service (NTIS)

The angle distribution of 5.3 micrometer radiation has been measured and the conversion factor determined for a TEA laser. Values obtained for the conversion factor are discussed and compared with calculated values for single crystalline zinc selenide. Th...

E. Daniels K. Gullberg B. Hartmann

1974-01-01

166

Improved Electroformed Structural Copper and Copper Alloys  

NASA Technical Reports Server (NTRS)

Electroforming offers a superior means for fabricating internally cooled heat exchangers and structures subjected to thermal environments. Copper is deposited from many such applications because of the good thermal conductivity. It suffers from mediocre yield strength as a structural material and loses mechanical strength at intermediate temperatures. Mechanical properties similar to those of electroformed nickel are desired. Phase 1 examined innovative means to improve deposited copper structural performance. Yield strengths as high as 483 MPa (70 ksi) were obtained with useful ductility while retaining a high level of purity essential to good thermal conductivity. Phase 2 represents a program to explore new additive combinations in copper electrolytes to produce a more fine, equiaxed grain which can be thermally stabilized by other techniques such as alloying in modest degrees and dispersion strengthening. Evaluation of new technology - such as the codeposition of fullerness (diamond-like) particles were made to enhance thermal conductivity in low alloys. A test fire quality tube-bundle engine was fabricated using these copper property improvement concepts to show the superiority of the new coppers and fabrications methods over competitive technologies such as brazing and plasma deposition.

Malone, G. A.; Hudson, W.; Babcock, B.; Edwards, R.

1998-01-01

167

Ferrimagnetic copper chloride hydroxide  

Microsoft Academic Search

Magnetic properties of copper chloride hydroxide were studied by using a superconducting quantum interference device. The coercivity of this material was more than 10 000 Oe at 2 K, which is the highest observed in the copper compounds. The magnetic susceptibility as a function of temperature revealed ferrimagnetism in the sample.

S G Yang; T Li; B L Xu; Y W Du

2003-01-01

168

COPPER RESEARCH UPDATE  

EPA Science Inventory

This presentation provides an update and overview of new research results and remaining research needs with respect to copper corrosion control issues. The topics to be covered include: occurrence of elevated copper release in systems that meet the Action Level; impact of water c...

169

Refractories for Copper Production  

Microsoft Academic Search

The furnaces used for producing molten copper from concentrates and scrap - flash: smelters, converters, and anode and fire-refining furnaces - present a unique combination of challenges to refractory life. Highly aggressive slags, mechanical stresses, batch operation, and increasingly higher operating temperatures all combine to destroy most refractory materials. Over the past generation, copper producers have adopted refractory materials biased

MARK E. SCHLESINGER

1996-01-01

170

Oxidation resistant copper  

SciTech Connect

Oxidation resistant particles composed of copper and at least one metal having a valence of +2 or +3 and having an intermediate lattice energy for the metal in its hydroxide form. The metal is selected from nickel, cobalt, iron, manganese, cadmium, zinc, tin, magnesium, calcium and chromium. In one embodiment, the phases of copper and at least one metal in the particles are separate and the concentration of the metal is greater near the surface of the particles than inwardly thereof. Process for making the oxidation resistant copper particles includes the steps of dissolving a copper salt and a salt of at least one of the metals in a suitable solvent or diluent; forming primary particles of copper and at least one metal in basic form by mixing a base and the salt solution; separating, washing and drying the primary particles; reducing the primary particles to metallic form; and heat treating the particles in metallic form at an elevated temperature.

Edelstein, A.S.; Kaatz, F.H.; Harris, V.G.

1993-11-15

171

Electrical transport and grain growth in solution-cast, chloride-terminated cadmium selenide nanocrystal thin films.  

PubMed

We report the evolution of electrical transport and grain size during the sintering of thin films spin-cast from soluble phosphine and amine-bound, chloride-terminated cadmium selenide nanocrystals. Sintering of the nanocrystals occurs in three distinct stages as the annealing temperature is increased: (1) reversible desorption of the organic ligands (?150 °C), (2) irreversible particle fusion (200-300 °C), and (3) ripening of the grains to >5 nm domains (>200 °C). Grain growth occurs at 200 °C in films with 8 atom % Cl(-), while films with 3 atom % Cl(-) resist growth until 300 °C. Fused nanocrystalline thin films (grain size = 4.5-5.5 nm) on thermally grown silicon dioxide gate dielectrics produce field-effect transistors with electron mobilities as high as 25 cm(2)/(Vs) and on/off ratios of 10(5) with less than 0.5 V hysteresis in threshold voltage without the addition of indium. PMID:24960255

Norman, Zachariah M; Anderson, Nicholas C; Owen, Jonathan S

2014-07-22

172

Synthesis and characterization of hexagonal nano-sized nickel selenide by simple hydrothermal method assisted by CTAB  

NASA Astrophysics Data System (ADS)

Nano-sized nickel selenide powders have been successfully synthesized via an improved hydrothermal route based on the reaction between NiCl 2·6H 2O, SeCl 4 and hydrazine (N 2H 4·H 2O) in water, in present of cetyltrimethyl ammonium bromide (CTAB) as surfactant, at various conditions. The products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and X-ray energy dispersive spectroscopy analysis. Effects of temperature, reaction time and reductant agent on the morphology, the particle sizes and the phase of the final products have been investigated. It was found that the phase and morphology of the products could be greatly influenced by these parameters. The synthesis procedure is simple and uses less toxic reagents than the previously reported methods. Photoluminescence (PL) was used to study the optical properties of NiSe samples.

Sobhani, Azam; Davar, Fatemeh; Salavati-Niasari, Masoud

2011-07-01

173

III-VI compound semiconductor indium selenide (In{sub 2}Se{sub 3}) nanowires: Synthesis and characterization  

SciTech Connect

The authors report the synthesis of one-dimensional indium selenide nanowire, a III-VI group compound semiconductor nanostructure with potential applications in data storage, solar cells, and optoelectronics. Nanoscale gold particles were used as catalysts and growth was also demonstrated using indium as self-catalyst. The growth mechanism is confirmed to be vapor-liquid-solid process by in situ heating experiments in which In and Se were found to diffuse back into the gold catalyst bead forming a Au-In-Se alloy that was molten at elevated temperatures. The morphology, composition, and crystal structure of the In{sub 2}Se{sub 3} nanowires (NWs) were analyzed by scanning electron microscopy, energy dispersive x-ray spectroscopy, and high-resolution transmission electron microscopy.

Sun Xuhui; Yu Bin; Ng, Garrick; Thuc Dinh Nguyen; Meyyappan, M. [Center for Nanotechnology, NASA Ames Research Center, Moffett Field, California 94035 (United States)

2006-12-04

174

An approach to global rovibrational analysis based on anharmonic ladder operators: Application to hydrogen selenide and hydrogen sulfide  

NASA Astrophysics Data System (ADS)

A formalism to model the ro-vibrational spectrum of triatomic asymmetric top molecules is presented. The quantum mechanical ro-vibrational kinetic and potential energy function is considered as a Taylor expansion in internal coordinates of Morse local oscillators. Thereafter, local Morse coordinates and momenta are expanded in terms of Morse Potential ladder operators. Only polyad-conserving terms are considered. Expansions of the kinetic and potential energies of the ro-vibrational Hamiltonian are considered up to sextic terms. The resulting Hamiltonian was diagonalized using a symmetry-adapted basis, generated by the eigenfunction method ( J.Q.Chen, Group Representation Theory for Physicists,World Scientific, 1989; R. Lemus, 2003 Mol.Phys., 101 2511-2528.). The model is applied to hydrogen sulfide (H_2S) and hydrogen selenide (H_2Se).

Perez-Bernal, F.; Carvajal, M.; Alvarez-Bajo, O.

2011-05-01

175

Killing of Bacteria by Copper Surfaces Involves Dissolved Copper?  

PubMed Central

Bacteria are rapidly killed on copper surfaces. However, the mechanism of this process remains unclear. Using Enterococcus hirae, the effect of inactivation of copper homeostatic genes and of medium compositions on survival and copper dissolution was tested. The results support a role for dissolved copper ions in killing.

Molteni, Cristina; Abicht, Helge K.; Solioz, Marc

2010-01-01

176

Arsenic activities in molten copper and copper sulfide melts  

NASA Astrophysics Data System (ADS)

In recent years, the concentration of the group Va elements such as arsenic, antimony, and bismuth has been increasing in copper concentrates. The elimination and recovery of these elements during the copper smelting process have presented serious problems. While the distribution of minor elements has been studied extensively, very little knowledge exists on the activities of these minor elements in copper mattes. Consequently, in this study the activities of arsenic were measured to determine activity coefficients of arsenic in the dilute solution region of molten copper, in Cu2S saturated copper, and in copper mattes equilibrated with copper at 1423 K by a mass spectrometric Knudsen effusion technique.

Hino, M.; Toguri, J. M.

1986-12-01

177

Copper sensitivity of Gonyaulax tamarensis  

Microsoft Academic Search

The copper sensitivity of the dinoflagellate Gonyaulax tamarensis was examined in artificial seawater medium. Two short term responses of the organism to copper toxicity are rapid loss of motility and reduced photosynthetic carbon fixation. The chelators tris(hydroxymethylamino)methane (Tris) and ethylenedinitrilotetraacetic acid (EDTA) were used to demonstrate that copper toxicity is a unique function of cupric ion activity. Copper additions to

D. M. Anderson; F. M. M. Morel

1978-01-01

178

Intracellular copper transport in mammals.  

PubMed

Copper is an essential cofactor for approximately a dozen cuproenzymes in which copper is bound to specific amino acid residues in an active site. However, free cuprous ions react readily with hydrogen peroxide to yield the deleterious hydroxyl radical. Therefore, copper homeostasis is regulated very tightly, and unbound copper is extremely low in concentration. Copper imported by the plasma membrane transport protein Ctr1 rapidly binds to intracellular copper chaperone proteins. Atox1 delivers copper to the secretory pathway and docks with either copper-transporting ATPase ATP7B in the liver or ATP7A in other cells. ATP7B directs copper to plasma ceruloplasmin or to biliary excretion in concert with a newly discovered chaperone, Murr1, the protein missing in canine copper toxicosis. ATP7A directs copper within the transgolgi network to the proteins dopamine beta-monooxgenase, peptidylglycine alpha-amidating monooxygenase, lysyl oxidase, and tyrosinase, depending on the cell type. CCS is the copper chaperone for Cu,Zn-superoxide dismutase; it delivers copper in the cytoplasm and intermitochondrial space. Cox17 delivers copper to mitochondria to cytochrome c oxidase via the chaperones Cox11, Sco1, and Sco2. Other copper chaperones may exist and might include metallothionein and amyloid precursor protein (APP). Genetic and nutritional studies have illustrated the essential nature of these copper-binding proteins; alterations in their levels are associated with severe pathology. PMID:15113935

Prohaska, Joseph R; Gybina, Anna A

2004-05-01

179

COPPER CABLE RECYCLING TECHNOLOGY  

SciTech Connect

The United States Department of Energy (DOE) continually seeks safer and more cost-effective technologies for use in deactivation and decommissioning (D&D) of nuclear facilities. The Deactivation and Decommissioning Focus Area (DDFA) of the DOE's Office of Science and Technology (OST) sponsors large-scale demonstration and deployment projects (LSDDPs). At these LSDDPs, developers and vendors of improved or innovative technologies showcase products that are potentially beneficial to the DOE's projects and to others in the D&D community. Benefits sought include decreased health and safety risks to personnel and the environment, increased productivity, and decreased costs of operation. The Idaho National Engineering and Environmental Laboratory (INEEL) generated a list of statements defining specific needs and problems where improved technology could be incorporated into ongoing D&D tasks. One such need is to reduce the volume of waste copper wire and cable generated by D&D. Deactivation and decommissioning activities of nuclear facilities generates hundreds of tons of contaminated copper cable, which are sent to radioactive waste disposal sites. The Copper Cable Recycling Technology separates the clean copper from contaminated insulation and dust materials in these cables. The recovered copper can then be reclaimed and, more importantly, landfill disposal volumes can be reduced. The existing baseline technology for disposing radioactively contaminated cables is to package the cables in wooden storage boxes and dispose of the cables in radioactive waste disposal sites. The Copper Cable Recycling Technology is applicable to facility decommissioning projects at many Department of Energy (DOE) nuclear facilities and commercial nuclear power plants undergoing decommissioning activities. The INEEL Copper Cable Recycling Technology Demonstration investigated the effectiveness and efficiency to recycle 13.5 tons of copper cable. To determine the effectiveness of separating out radioactive contamination, the copper cable was coated with a surrogate contaminant. The demonstration took place at the Bonneville County Technology Center in Idaho Falls, Idaho.

Chelsea Hubbard

2001-05-01

180

Copper as a biocidal tool.  

PubMed

Copper ions, either alone or in copper complexes, have been used to disinfect liquids, solids and human tissue for centuries. Today copper is used as a water purifier, algaecide, fungicide, nematocide, molluscicide as well as an anti-bacterial and anti-fouling agent. Copper also displays potent anti-viral activity. This article reviews (i) the biocidal properties of copper; (ii) the possible mechanisms by which copper is toxic to microorganisms; and (iii) the systems by which many microorganisms resist high concentrations of heavy metals, with an emphasis on copper. PMID:16101497

Borkow, Gadi; Gabbay, Jeffrey

2005-01-01

181

Copper chaperones: function, structure and copper-binding properties.  

PubMed

Copper is an absolute requirement for living systems and the intracellular trafficking of this metal to copper-dependent proteins is fundamental to normal cellular metabolism. The copper chaperones perform the dual functions of trafficking and the prevention of cytoplasmic exposure to copper ions in transit. Only a small number of copper chaperones have been identified at this time but their conservation across plant, bacterial and animal species suggests that the majority of living systems utilise these proteins for copper routing. The available data suggest that each copper-dependent protein in the cell is served by a specific copper chaperone. Although copper chaperones cannot be substituted for one another in a given cell type, copper chaperones that deliver to the same protein in different cell types appear to be functionally equivalent. The majority of the copper chaperones identified thus far have an "open-faced beta-sandwich" global fold with a conserved MXCXXC metal-binding motif. Specificity for a given copper-dependent protein appears to be mediated by the residues surrounding the copper-binding motif. Copper binds to such proteins as Cu(I) in a trigonal complex with three sulfur ligands. Only the copper chaperone specific for cytochrome-c-oxidase, Cox17, deviates from this design. PMID:10499084

Harrison, M D; Jones, C E; Dameron, C T

1999-04-01

182

Structure and composition of the superconducting phase in alkali iron selenide KyFe1.6+xSe2  

NASA Astrophysics Data System (ADS)

We use neutron diffraction to study the temperature evolution of the average structure and local lattice distortions in insulating and superconducting potassium iron selenide KyFe1.6+xSe2. In the high temperature paramagnetic state, both materials have a single phase with a crystal structure similar to that of the BaFe2As2 family of iron pnictides. While the insulating KyFe1.6+xSe2 forms a ?5 ×?5 iron vacancy ordered block antiferromagnetic (AF) structure at low temperature, the superconducting compounds spontaneously phase separate into an insulating part with ?5 ×?5 iron vacancy order and a superconducting phase with chemical composition of KzFe2Se2 and BaFe2As2 structure. Therefore, superconductivity in alkaline iron selenides arises from alkali deficient KzFe2Se2 in the matrix of the insulating block AF phase.

Carr, Scott V.; Louca, Despina; Siewenie, Joan; Huang, Q.; Wang, Aifeng; Chen, Xianhui; Dai, Pengcheng

2014-04-01

183

Zinc sulfide and zinc selenide immersion gratings for astronomical high-resolution spectroscopy: evaluation of internal attenuation of bulk materials in the short near-infrared region  

Microsoft Academic Search

We measure the internal attenuation of bulk crystals of chemical vapor deposition zinc selenide (CVD-ZnS), chemical vapor deposition zinc sulfide (CVD-ZnSe), Si, and GaAs in the short near-infrared (sNIR) region to evaluate the possibility of astronomical immersion gratings with those high refractive index materials. We confirm that multispectral grade CVD-ZnS and CVD-ZnSe are best suited for the immersion gratings, with

Yuji Ikeda; Naoto Kobayashi; Sohei Kondo; Chikako Yasui; Paul J. Kuzmenko; Hitoshi Tokoro; Hiroshi Terada

2009-01-01

184

Volatility of copper  

SciTech Connect

The relevant aqueous thermodynamics of copper and its oxides are evaluated and summarized with emphasis on solubility, hydrolysis, and complexation. The solubilities of metallic copper, solid cuprous and cupric oxides in steam measured by Pocock and Stewart in 1963 are discussed and the latter data are fitted in the form of established empirical equations and compared to other existing results. No other sources of data were found for the solubility of copper and cupric oxide in steam and even these data are very limited. Discussion of corresponding available solubility data on both oxide phases in liquid water is given. The possible effects of complexing agents are considered. A brief discussion is provided of the role of surface adsorption in determining the fate of dissolved copper in the boiler. 37 refs., 5 figs., 3 tabs.

Palmer, D.A.; Simonson, J.M.; Joyce, D.B.

1996-08-01

185

Micromachining with copper lasers  

NASA Astrophysics Data System (ADS)

In recent years the copper laser has undergone extensive development and has emerged as a leading and unique laser for micromachining. The copper laser is a high average power (10 - 250 W), high pulse repetition rate (2 - 32 kHz), visible laser (511 nm and 578 nm) that produces high peak power (typically 200 kW), short pulses (30 ns) and very good beam quality (diffraction limited). This unique set of laser parameters results in exceptional micro-machining in a wide variety of materials. Typical examples of the capabilities of the copper laser include the drilling of small holes (10 - 200 micrometer diameter) in materials as diverse as steel, ceramic, diamond and polyimide with micron precision and low taper (less than 1 degree) cutting and profiling of diamond. Application of the copper laser covers the electronic, aerospace, automotive, nuclear, medical and precision engineering industries.

Knowles, M.; Bell, A.; Foster-Turner, G.; Rutterford, G.; Chudzicki, J.; Kearsley, Andrew J.

1997-04-01

186

Entrainment behavior of copper and copper matte in copper smelting operations  

Microsoft Academic Search

In copper smelting, the loss of copper to the slag due to entrainment is largely influenced by the flotation of copper metal\\u000a and\\/or matte in the slag phase. To evaluate this behavior, the surface tension of copper as a function of temperature and\\u000a oxygen pressure and the interfacial tension of the copper-iron matte-slag system as a function of matte grade

S. W. Ip; J. M. Toguri

1992-01-01

187

Copper and Copper Alloy Powders. Seminar Held on 18th December 1976.  

National Technical Information Service (NTIS)

This report contains the following papers: Types, Properties and Uses of Copper Powder; Production of Copper & Copper Alloy Powders for General Engineering Applications; Bronze Powders; Atomized Copper and Copper Based Powders; Process and Equipment for t...

1976-01-01

188

Electrowinning of Copper from Chloride Solutions.  

National Technical Information Service (NTIS)

Electrowinning of copper from chloride solutions was studied in a diaphragm cell. The copper powder product was shaken periodically from the cathode and removed from the bottom of the cell. The effects of copper concentration, brine concentration, copper ...

R. E. Mussler R. S. Olsen T. T. Campbell

1975-01-01

189

Copper trafficking to the mitochondrion and assembly of copper metalloenzymes.  

PubMed

Copper is required within the mitochondrion for the function of two metalloenzymes, cytochrome c oxidase (CcO) and superoxide dismutase (Sod1). Copper metallation of these two enzymes occurs within the mitochondrial intermembrane space and is mediated by metallochaperone proteins. Cox17 is a key copper donor to two accessory proteins, Sco1 and Cox11, to form the two copper centers in the mature CcO complex. Ccs1 is the necessary metallochaperone for the copper metallation of Sod1 in the IMS as well as within the cytoplasm where the bulk of Sod1 resides. Copper ions used in the metallation of CcO and Sod1 appear to be provided by a novel copper pool within the mitochondrial matrix. This review documents copper ion shuttling within the mitochondrion and the proteins that mediate assembly of active CcO and Sod1. PMID:16631971

Cobine, Paul A; Pierrel, Fabien; Winge, Dennis R

2006-07-01

190

Physical and Mechanical Properties of Copper and Copper Alloys  

SciTech Connect

High strength, high conductivity copper alloys are prime candidates for high heat flux applications in fusion energy systems. This chapter reviews the physical and mechanical properties of pure copper and copper alloys with the focus on precipitation-hardened CuCrZr and dispersion-strengthened CuAl25 alloys. The effect of neutron irradiation on copper and copper alloys is reviewed in terms of radiation effects on physical properties and mechanical properties (tensile properties, fracture toughness, fatigue and creep-fatigue), irradiation creep and void swelling. The effect of irradiation on the microstructure of copper and copper alloys and dislocation channeling is also presented. Joining techniques for copper alloys in fusion plasma facing components are briefly discussed.

Li, Meimei [Argonne National Laboratory (ANL); Zinkle, Steven J [ORNL

2012-01-01

191

Bacterial Killing by Dry Metallic Copper Surfaces?  

PubMed Central

Metallic copper surfaces rapidly and efficiently kill bacteria. Cells exposed to copper surfaces accumulated large amounts of copper ions, and this copper uptake was faster from dry copper than from moist copper. Cells suffered extensive membrane damage within minutes of exposure to dry copper. Further, cells removed from copper showed loss of cell integrity. Acute contact with metallic copper surfaces did not result in increased mutation rates or DNA lesions. These findings are important first steps for revealing the molecular sensitive targets in cells lethally challenged by exposure to copper surfaces and provide a scientific explanation for the use of copper surfaces as antimicrobial agents for supporting public hygiene.

Santo, Christophe Espirito; Lam, Ee Wen; Elowsky, Christian G.; Quaranta, Davide; Domaille, Dylan W.; Chang, Christopher J.; Grass, Gregor

2011-01-01

192

Distribution of Sulfide and Oxide Copper in Copper Mill Tailings.  

National Technical Information Service (NTIS)

Studies were made to determine the character and distribution of the copper lost in copper mill tailings. Acid soluble (oxide) and acid insoluble (sulfide) copper were determined for heavy-liquid sink and float products of screen-sized fractions from 12 c...

A. R. Rule J. C. White

1971-01-01

193

Oxidation of the copper alloy with pure copper plating  

Microsoft Academic Search

The oxidation failure of a copper alloy lead frame with\\/without a copper plating layer was investigated. The oxidation rate and adhesion strength of oxide films on copper alloy substrates were studied by measuring the thickness and by carrying out peel tests. The adhesion strength of the oxide film was mainly influenced by the composition but not the thickness of the

Yuchen Liu; Jin Hu; Anmin Hu; Ming Li; Dali Mao

2012-01-01

194

Integration of thin electroless copper films in copper interconnect metallization  

Microsoft Academic Search

Deposition of a thin electroless copper films on PVD copper seed layers in interconnect metallization was investigated for formation of a composite seed layer. Issues such as film stress, adhesion, electrical reliability, and hydrogen incorporation were addressed to determine feasibility of the process for the fabrication of real device structures. The formation of blisters between the copper films and underlying

E. Webb; C. Witt; T. Andryuschenko; J. Reid

2004-01-01

195

Preparation of high purity copper fluoride by fluorinating copper hydroxyfluoride  

NASA Technical Reports Server (NTRS)

Copper fluoride containing no more than 50 ppm of any contaminating element was prepared by the fluorination of copper hydroxyfluoride. The impurity content was obtained by spark source mass spectrometry. High purity copper fluoride is needed as a cathode material for high energy density batteries.

King, R. B.; Lundquist, J. R.

1969-01-01

196

24-hour urine copper test  

MedlinePLUS

The 24-hour urine copper test measures the amount of copper in a urine sample. ... A 24-hour urine sample is needed. On day 1, urinate into the toilet when you get up in the morning. Afterwards, collect ...

197

Exploring for Copper Deposits  

NSDL National Science Digital Library

In this activity, students assume the role of a geologist prospecting for copper deposits. From the background material, they will learn what ore deposits are and some important factors in their origin; and learn about a type of ore deposit known as a porphyry copper deposit. They will plot data from a table onto maps and use a geologic map, a soil geochemistry map, and a sediment geochemistry map to help locate the porphyry copper deposit. As a result of this activity, the students will be able to calculate an ore grade and determine whether or not an ore deposit is economically profitable based on its grade, size, and production costs. Worksheets and data tables are included.

198

Preparation of Few-Layer Bismuth Selenide by Liquid-Phase-Exfoliation and Its Optical Absorption Properties  

NASA Astrophysics Data System (ADS)

Bismuth selenide (Bi2Se3), a new topological insulator, has attracted much attention in recent years owing to its relatively simple band structure and large bulk band gap. Compared to bulk, few-layer Bi2Se3 is recently considered as a highly promising material. Here, we use a liquid-phase exfoliation method to prepare few-layer Bi2Se3 in N-methyl-2-pyrrolidone or chitosan acetic solution. The resulted few-layer Bi2Se3 dispersion demonstrates an interesting absorption in the visible light region, which is different from bulk Bi2Se3 without any absorption in this region. The absorption spectrum of few-layer Bi2Se3 depends on its size and layer number. At the same time, the nonlinear and saturable absorption of few-layer Bi2Se3 thin film in near infrared is also characterized well and further exploited to generate laser pulses by a passive Q-switching technique. Stable Q-switched operation is achieved with a lower pump threshold of 9.3 mW at 974 nm, pulse energy of 39.8 nJ and a wide range of pulse-repetition-rate from 6.2 to 40.1 kHz. Therefore, the few-layer Bi2Se3 may excite a potential applications in laser photonics and optoelectronic devices.

Sun, Liping; Lin, Zhiqin; Peng, Jian; Weng, Jian; Huang, Yizhong; Luo, Zhengqian

2014-04-01

199

Oxidation mechanisms of dimethyl selenide and selenoxide in the atmosphere initiated by OH radical. A theoretical study  

NASA Astrophysics Data System (ADS)

The reaction mechanisms for dimethyl selenide (DMSe) and dimethyl selenoxide (DMSeO) with OH radical are studied by using quantum chemistry calculations. The structures are optimized at MP2 levels, and electronic energies at Gaussian-4 level. Addition complexes are found between reactants as (CH 3) 2Se · OH, (CH 3) 2Se(O) · OH, and (CH 3) 2SeO · HO, which serve as reaction intermediates for further decompositions to CH 3SeOH + CH 3/CH 3SeCH 2 + H 2O, CH 3Se(O)OH + CH 3, and CH 3Se(O)CH 2 + H 2O, respectively. Under the atmospheric conditions, the dominant product channel for DMSe + OH is CH 3SeCH 2 and (CH 3) 2Se · OH, of which the latter is subsequently converted to DMSeO; while the main product for DMSeO + OH is CH 3Se(O)OH. Hydrate formation for DMSeO would not alter the branch ratios because of its small fraction in the atmosphere.

Wang, Liming; Tang, Aili

2011-04-01

200

Atmospheric Doping Affects on the Transport Properties of the Topological Insulator Bismuth Selenide (Bi2Se3) Grown By MBE  

NASA Astrophysics Data System (ADS)

During the last five years much experimental work has been done to determine if the theoretical prediction of topological insulting (TI) states truly exist. Angle resolved photo emission spectroscopy (ARPES) measurements have shown that a Dirac type linear dispersion does exist for a variety of materials, and the surface states have been observed by direct transport measurements. The next challenge is to isolate the surface electrons by removing the bulk conduction. This not trivial because bismuth selenide's Fermi energy sits in the conduction band, and most of the measured carriers are due to these bulk states. The prediction is that the surface states are robust under perturbation, but like standard semiconductors, Bi2Se3's bulk states are sensitive to doping. I will report on our work done on how the transport properties of MBE grown Bi2Se3 thin films are affected by atmospheric dopants such as oxygen and water vapor. Future prospects for studying TIs such Bi2Se3 and ultimately building a device depend on being able to tune the Fermi level into the gap thereby isolating the surface states, and then passivating the surface against contamination due to atmospheric oxygen and water vapor.

Brahlek, Matthew; Kim, Yong Seung; Bansal, Namrata; Edrey, Eliav; Oh, Seongshik

2011-03-01

201

Preparation of few-layer bismuth selenide by liquid-phase-exfoliation and its optical absorption properties.  

PubMed

Bismuth selenide (Bi2Se3), a new topological insulator, has attracted much attention in recent years owing to its relatively simple band structure and large bulk band gap. Compared to bulk, few-layer Bi2Se3 is recently considered as a highly promising material. Here, we use a liquid-phase exfoliation method to prepare few-layer Bi2Se3 in N-methyl-2-pyrrolidone or chitosan acetic solution. The resulted few-layer Bi2Se3 dispersion demonstrates an interesting absorption in the visible light region, which is different from bulk Bi2Se3 without any absorption in this region. The absorption spectrum of few-layer Bi2Se3 depends on its size and layer number. At the same time, the nonlinear and saturable absorption of few-layer Bi2Se3 thin film in near infrared is also characterized well and further exploited to generate laser pulses by a passive Q-switching technique. Stable Q-switched operation is achieved with a lower pump threshold of 9.3?mW at 974?nm, pulse energy of 39.8?nJ and a wide range of pulse-repetition-rate from 6.2 to 40.1?kHz. Therefore, the few-layer Bi2Se3 may excite a potential applications in laser photonics and optoelectronic devices. PMID:24762534

Sun, Liping; Lin, Zhiqin; Peng, Jian; Weng, Jian; Huang, Yizhong; Luo, Zhengqian

2014-01-01

202

Reduction of elemental selenium to selenide: Experiments with anoxic sediments and bacteria that respire Se-oxyanions  

USGS Publications Warehouse

A selenite-respiring bacterium, Bacillus selenitireducens, produced significant levels of Se(-II) (as aqueous HSe-) when supplied with Se(O). B. selenitireducens was also able to reduce selenite [Se(IV)] through Se(O) to Se(-II). Reduction of Se(O) by B.selenitireducens was more rapid in cells grown on colloidal sulfur [S(O)] or Se(IV) as their electron acceptor than for cell lines grown on fumarate. In contrast, three cultures of selenate-respiring bacteria, Sulfurospirillum barnesii, B. arsenicoselenatis, and Selenihalanaerobacter shriftii either were unable to reduce Se(O) to Se(-II) or had only a very limited capacity to achieve this reduction. Biological reduction of Se(O) to Se(-II) was observed during incubation of estuarine sediment slurries, while no such activity was noted in formalin-killed controls. The majority of the Se(-II) produced was found in the sediments as a solid precipitate of FeSe, rather than in solution as HSe-. These results demonstrate that certain anaerobic bacteria have the capacity to reduce Se(O) to Se(-II), providing a possible biological explanation for the occurrence of the selenide species in some sedimentary rocks.

Herbel, M. J.; Blum, J. S.; Oremland, R. S.; Borglin, S. E.

2003-01-01

203

Synthesis of a new alkali metal-organic solvent intercalated iron selenide superconductor with Tc ? 45 K  

NASA Astrophysics Data System (ADS)

We report on a new iron selenide superconductor with a Tc onset of 45 K and the nominal composition Lix(C5H5N)yFe2-zSe2, synthesized via intercalation of dissolved alkaline metal in anhydrous pyridine at room temperature. This superconductor exhibits a broad transition, reaching zero resistance at 10 K. Magnetization measurements reveal a superconducting shielding fraction of approximately 30%. Analogous phases intercalated with Na, K and Rb were also synthesized and characterized. The superconducting transition temperature of Lix(C5H5N)yFe2-zSe2 is clearly enhanced in comparison to those of the known superconductors FeSe0.98 (Tc ˜ 8 K) and AxFe2-ySe2 (Tc ˜ 27-32 K) and is in close agreement with critical temperatures recently reported for Lix(NH3)yFe2-zSe2. Post-annealing of intercalated material (Lix(C5H5N)yFe2-zSe2) at elevated temperatures drastically enlarges the c-parameter of the unit cell (˜44%) and increases the superconducting shielding fraction to nearly 100%. Our findings indicate a new synthesis route leading to possibly even higher critical temperatures for materials in this class: by intercalation of organic compounds between Fe-Se layers.

Krzton-Maziopa, A.; Pomjakushina, E. V.; Pomjakushin, V. Yu; von Rohr, F.; Schilling, A.; Conder, K.

2012-09-01

204

Facile hot-injection synthesis of stoichiometric Cu2ZnSnSe4 nanocrystals using bis(triethylsilyl) selenide.  

PubMed

Cu2ZnSnSe4 is a prospective material as an absorber in thin film solar cells due to its many advantages including direct band gap, high absorption coefficient, low toxicity, and relative abundance (indium-free) of its elements. In this report, CZTSe nanoparticles have been synthesized by the hot-injection method using bis-(triethylsilyl)selenide [(Et3Si)2Se] as the selenium source for the first time. Energy dispersive X-ray spectroscopy (EDS) confirmed the stoichiometry of CZTSe nanoparticles. X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies showed that the nanocrystals were single phase polycrystalline with their size within the range of 25-30 nm. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy measurements ruled out the existence of secondary phases such as Cu2SnSe3 and ZnSe. The effect of reaction time and precursor injection order on the formation of stoichiometric CZTSe nanoparticles has been studied by Raman spectroscopy. UV-vis-NIR data indicate that the CZTSe nanocrystals have an optical band gap of 1.59 eV, which is optimal for photovoltaic applications. PMID:24823944

Jin, Chunyu; Ramasamy, Parthiban; Kim, Jinkwon

2014-06-01

205

Preparation of Few-Layer Bismuth Selenide by Liquid-Phase-Exfoliation and Its Optical Absorption Properties  

PubMed Central

Bismuth selenide (Bi2Se3), a new topological insulator, has attracted much attention in recent years owing to its relatively simple band structure and large bulk band gap. Compared to bulk, few-layer Bi2Se3 is recently considered as a highly promising material. Here, we use a liquid-phase exfoliation method to prepare few-layer Bi2Se3 in N-methyl-2-pyrrolidone or chitosan acetic solution. The resulted few-layer Bi2Se3 dispersion demonstrates an interesting absorption in the visible light region, which is different from bulk Bi2Se3 without any absorption in this region. The absorption spectrum of few-layer Bi2Se3 depends on its size and layer number. At the same time, the nonlinear and saturable absorption of few-layer Bi2Se3 thin film in near infrared is also characterized well and further exploited to generate laser pulses by a passive Q-switching technique. Stable Q-switched operation is achieved with a lower pump threshold of 9.3?mW at 974?nm, pulse energy of 39.8?nJ and a wide range of pulse-repetition-rate from 6.2 to 40.1?kHz. Therefore, the few-layer Bi2Se3 may excite a potential applications in laser photonics and optoelectronic devices.

Sun, Liping; Lin, Zhiqin; Peng, Jian; Weng, Jian; Huang, Yizhong; Luo, Zhengqian

2014-01-01

206

Solvothermal synthesis, deposition and characterization of cadmium selenide (CdSe) thin films by thermal evaporation technique  

NASA Astrophysics Data System (ADS)

Nanocrystalline compound semiconductor Cadmium Selenide was synthesized by the solvothermal method using Cd(NO 3) 2.4H 2O and Se metal granules. The synthesized nanocrystalline CdSe particles were subjected to vacuum annealing at 450 °C to maintain the hexagonal phase. The as synthesized and annealed powders were analyzed using XRD, SEM, EDX and DTA. The X-ray diffraction pattern of the as synthesized powder shows cubic phase, whereas the 450 °C annealed CdSe powder exhibits hexagonal phase. The annealed nanocrystalline CdSe was pelletized using hydraulic pressure of 5 ton and used to deposit thin films at different substrate temperature like Room Temperature (RT), 150, 250, 350 and 450 °C by thermal evaporation using glass as substrate. The deposited films were subjected to XRD, SEM, EDX, UV-vis, Photoluminescence, Raman Spectroscopy and Hall Effect measurement to study their properties. The thickness of the films was measured with thickness profilometer. The thermally deposited CdSe films exhibit the hexagonal structure with n-type conductivity.

Shyju, T. S.; Anandhi, S.; Indirajith, R.; Gopalakrishnan, R.

2011-12-01

207

Copper-phosphorus alloys offer advantages in brazing copper  

SciTech Connect

Copper-phosphorus brazing alloys are used extensively for joining copper, especially refrigeration and air-conditioning copper tubing and electrical conductors. What is the effect of phosphorus when alloyed with copper? The following are some of the major effects: (1) It lowers the melt temperature of copper (a temperature depressant). (2) It increases the fluidity of the copper when in the liquid state. (3) It acts as a deoxidant or a fluxing agent with copper. (4) It lowers the ductility of copper (embrittles). There is a misconception that silver improves the ductility of the copper-phosphorus alloys. In reality, silver added to copper acts in a similar manner as phosphorus. The addition of silver to copper lowers the melt temperature (temperature depressant) and decreases the ductility. Fortunately, the rate and amount at which silver lowers copper ductility is significantly less than that of phosphorus. Therefore, taking advantage of the temperature depressant property of silver, a Ag-Cu-P alloy can be selected at approximately the same melt temperature as a Cu-P alloy, but at a lower phosphorus content. The lowering of the phosphorus content actually makes the alloy more ductile, not the silver addition. A major advantage of the copper-phosphorus alloys is the self-fluxing characteristic when joining copper to copper. They may also be used with the addition of a paste flux on brass, bronze, and specialized applications on silver, tungsten and molybdenum. Whether it is selection of the proper BCuP alloy or troubleshooting an existing problem, the suggested approach is a review of the desired phosphorus content in the liquid metal and how it is being altered during application. In torch brazing, a slight change in the oxygen-fuel ratio can affect the joint quality or leak tightness.

Rupert, W.D. [Engelhard Corp., Warwick, RI (United States)

1996-05-01

208

High adherence copper plating process  

DOEpatents

A process is described for applying copper to a substrate of aluminum or steel by electrodeposition and for preparing the surface of an aluminum or steel substrate for the electrodeposition of copper. Practice of the invention provides good adhesion of the copper layer to either substrate.

Nignardot, H.

1993-09-21

209

Brazing copper to dispersion-strengthened copper  

SciTech Connect

The Advanced Photon Source (APS) is a state-of-the-art synchrotron light source that will produce intense x-ray beams, which will allow the study of smaller samples and faster reactions and processes at a greater level of detail that has been possible to date. The beam is produced by using third-generation insertion devices in a 7 GeV electron/positron storage ring that is 1100 meters in circumference. The heat load from these intense high power devices is very high and certain components must sustain total heat loads of 3 to 15 kW and heat fluxes of 30 W/mm{sup 2}. Because the beams will cycle on and off many times, thermal shock and fatigue will be a problem. High heat flux impinging on a small area causes a large thermal gradient that results in high stress. GlidCop{reg_sign}, a dispersion strengthened copper, is the desired material because of its high thermal conductivity and superior mechanical properties as compared to copper and its alloys. GlidCop is not amenable to joining by fusion welding, and brazing requires diligence because of high diffusivity. Brazing procedures were developed using optical and scanning electron microscopy.

Ryding, D.G.; Allen, D.; Lee, R.

1996-08-01

210

Solvent-controlled halo-selective selenylation of aryl halides catalyzed by Cu(II) supported on Al2O3. A general protocol for the synthesis of unsymmetrical organo mono- and bis-selenides.  

PubMed

Alumina-supported Cu(II) efficiently catalyzes selenylation of aryl iodides and aryl bromides by diaryl, dialkyl, and diheteroaryl diselenides in water and PEG-600, respectively, leading to a general route toward synthesis of unsymmetrical diaryl, aryl-alkyl, aryl-heteroaryl, and diheteroaryl selenides. A sequential reaction of bromoiodobenzene with one diaryl/diheteroaryl/dialkyl diselenide in water and another diaryl/diheteroaryl/dialkyl diselenide in PEG-600 in the second step produces unsymmetrical diaryl, diheteroaryl, or aryl-alkyl bis-selanyl benzene. A library of functionalized organo mono- and bis-selenides, including a potent biologically active molecule and a couple of analogues of bioactive selenides, were obtained in high yields by this protocol. The reactions are chemoselective and high yielding. The Cu-Al2O3 catalyst is recycled for seven runs without any appreciable loss of activity. PMID:23786642

Chatterjee, Tanmay; Ranu, Brindaban C

2013-07-19

211

Cohesion margin of copper  

Microsoft Academic Search

Measurements on the mechanical properties of copper-bismuth alloys show that the only effect of bismuth within the solid solution range is to reduce the true tensile strength of the alloys—there is no detectable effect on plastic behaviour or on the elastic limit. Intergranular fracture occurs by the formation of grain boundary crack nuclei, these being seen in alloys containing as

E. D. Hondeos; D. McLean

1974-01-01

212

Superhydrophobic Copper Surfaces  

NSDL National Science Digital Library

This lesson from The Lawrence Hall of Science was taught in fall 2012 and focuses on superhydrophobic and superhydrophilic surfaces. Students will experiment with these materials by chemically modifying copper. This page includes links to the Source Article for the Hands-on Module as well as four documents for instructor use in teaching the lab.

2014-06-03

213

Physical and biophysical assessment of highly fluorescent, magnetic quantum dots of a wurtzite-phase manganese selenide system.  

PubMed

Combining fluorescence and magnetic features in a non-iron based, select type of quantum dots (QDs) can have immense value in cellular imaging, tagging and other nano-bio interface applications, including targeted drug delivery. Herein, we report on the colloidal synthesis and physical and biophysical assessment of wurtzite-type manganese selenide (MnSe) QDs in cell culture media. Aiming to provide a suitable colloidal system of biological relevance, different concentrations of reactants and ligands (e.g., thioglycolic acid, TGA) have been considered. The average size of the QDs is ?7 nm, which exhibited a quantum yield of ?75% as compared to rhodamine 6 G dye(®). As revealed from time-resolved photoluminescence (TR-PL) response, the near band edge emission followed a bi-exponential decay feature with characteristic times of ?0.64 ns and 3.04 ns. At room temperature, the QDs were found to exhibit paramagnetic features with coercivity and remanence impelled by TGA concentrations. With BSA as a dispersing agent, the QDs showed an improved optical stability in Dulbecco's Modified Eagle Media(®) (DMEM) and Minimum Essential Media(®) (MEM), as compared to the Roswell Park Memorial Institute(®) (RPMI-1640) media. Finally, the cell viability of lymphocytes was found to be strongly influenced by the concentration of MnSe QDs, and had a safe limit upto 0.5 ?M. With BSA inclusion in cell media, the cellular uptake of MnSe QDs was observed to be more prominent, as revealed from fluorescence imaging. The fabrication of water soluble, nontoxic MnSe QDs would open up an alternative strategy in nanobiotechnology, while preserving their luminescent and magnetic properties intact. PMID:24960126

Sarma, Runjun; Das, Queen; Hussain, Anowar; Ramteke, Anand; Choudhury, Amarjyoti; Mohanta, Dambarudhar

2014-07-11

214

Thermoelectric properties of bismuth-selenide films with controlled morphology and texture grown using pulsed laser deposition  

NASA Astrophysics Data System (ADS)

Polycrystalline, thermoelectric thin films of bismuth selenide (Bi2Se3) were grown on SiO2/Si (1 1 1) substrates, using pulsed laser deposition (PLD). Bi2Se3 films with highly c-axis-oriented and controlled textures were fabricated by maintaining the helium gas pressure (P) between 0.7 and 173 Pa and the substrate temperature (Ts) between 200 and 350 °C. The carrier concentration (n) of films decreased with increasing P, which was attributed to the increase of Se concentration from Se deficiency (P ? 6.7 Pa) to stoichiometry to slight Se enrichment (P ? 40 Pa). The Seebeck coefficient (S) was enhanced considerably because of the reduction in n, following the S ˜ n-2/3 relation approximately. The average grain size increased from approximately 100 to 500 nm when Ts was raised from 200 to 350 °C, resulting in enhanced carrier mobility (?) and electrical conductivity (?) and a reduced full width at half maximum of (0 0 6) peaks. The shape of grains transformed from rice-like at Ts of 200-250 °C to layered-hexagonal platelets (L-HPs) or super-layered flakes (S-LFs) at Ts of 300-350 °C. Films that were grown at 300 °C and 40 Pa and contained highly c-axis oriented L-HPs possessed the highest power factor (PF = S2?), which reached 5.54 ?W cm-1 K-2, where S = 75.8 ?V/K and ? = 963.8 S cm-1.

Le, Phuoc Huu; Liao, Chien-Neng; Luo, Chih Wei; Lin, Jiunn-Yuan; Leu, Jihperng

2013-11-01

215

Theoretical investigation of electronic states and spectroscopic properties of tellurium selenide molecule employing relativistic effective core potentials.  

PubMed

Ab initio based relativistic configuration interaction calculations have been performed to study the electronic states and spectroscopic properties of tellurium selenide (TeSe) - the heaviest heteronuclear diatomic group 16-16 molecule. Potential energy curves of several spin-excluded (?-S) electronic states of TeSe have been constructed and spectroscopic constants of low-lying bound ?-S states within 3.85 eV are reported in the first stage of calculations. The X(3)?(-), a(1)? and b(1)?(+) are found as the ground, first excited and second excited state, respectively, at the ?-S level and all these three states are mainly dominated by …?(4)?(*2) configuration. The computed ground state dissociation energy is in very good agreement with the experimental results. In the next stage of calculations, effects of spin-orbit coupling on the potential energy curves and spectroscopic properties of the species are investigated in details and compared with the existing experimental results. After inclusion of spin-orbit coupling the X(3)(1)?(-)(0(+)) is found as the ground-state spin component of TeSe. The computed spin-orbit splitting between two components of X(3)?(-) state is 1285 cm(-1). Also, significant amount of spin-orbit splitting are found between spin-orbit components (?-components) of several other excited states. Transition moments of some important spin-allowed and spin-forbidden transitions are calculated from configuration interaction wave functions. The spin-allowed transition B(3)?(-)-X(3)?(-) and spin-forbidden transition b(1)?(+)(0(+))-X(3)(1)?(-)(0(+)) are found to be the strongest in their respective categories. Electric dipole moments of all the bound ?-S states along with those of the two ?-components of X(3)?(-) are also calculated in the present study. PMID:24509540

Chattopadhyaya, Surya; Nath, Abhijit; Das, Kalyan Kumar

2014-04-24

216

Bend stiffness of copper and copper alloy foils  

Microsoft Academic Search

Loop stiffness and permanent deflection in bend testing of tough pitch copper foil and three kinds of copper alloy foils have been evaluated as bend stiffness. The copper alloy foils, in particular precipitation-hardened NK120 and C7025, exhibited high loop stiffness. High Young’s moduli of the alloy foils, which were confirmed by a cantilever resonance method, are considered to increase the

Yasuo Tomioka; Norio Yuki

2004-01-01

217

Copper losses and thermodynamic considerations in copper smelting  

Microsoft Academic Search

A relationship between copper in slag and copper in matte during copper sulfide smelting has been derived using industrial\\u000a data from 42 plants employing blast furnaces, reverberatory furnaces, flash furnaces, and Mitsubishi smelting furnaces together\\u000a with the available thermodynamic equilibrium data for Cu-Fe-S-O, FeO-SiO2, and Cu-Fe-S systems and laboratory slag-matte equilibrium information. A copper smelting diagram showing oxygen potential;\\u000a sulfur

R. Sridhar; J. M. Toguri; S. Simeonov

1997-01-01

218

[Determination of gold in copper matte and sintered copper material].  

PubMed

Ore sample, pretreated at 650 degrees C, was decomposed with aqua regia. Gold in the sample solution was then pre-concentrated by adsorbing with polyurethane foam plastic, released with thiourea solution, and determined by inductively coupled plasma-atomic emission spectrometry and flame atomic absorption spectrometry. Based on the characteristic of the copper matte and sinter containing copper, the effects of sample dissolving condition, matrix effect and interference of coexisting elements were investigated. The accuracy, precision and detection limit were discussed. The results of test show that both of the two methods were suitable for determining the contents of gold in copper matte and sintered copper material. PMID:21800614

Ge, Yu-wei; Xiao, Li-mei; Suo, Jin-ling; Wang, Cheng; Hu, Xiao-min; Zhao, Shu-yun

2011-05-01

219

Copper emission during thermal treatment of simulated copper sludge.  

PubMed

This study evaluates Cu emissions in air-particulate and gas phases during thermal treatment of simulated copper sludge by a rotary kiln. Influences of operating parameters, including treatment temperature (400-700 degrees C), rotary speed (0.89-2.00 rpm) and copper content in sludge (1% to 5% by weight) on copper emissions were investigated. The toxicity characteristic leaching procedure (TCLP) and scanning electron microscopy (SEM) were also conducted to evaluate copper leaching and the surface structure of thermally treated sludge, respectively. The results indicated that (1) low Cu emissions in air-particulate and gas phases were associated with the two operating conditions of 400-500 degrees C at 0.89-1.39 rpm and 600-700 degrees C at 2.00 rpm; (2) temperatures and rotary speeds did not affect gaseous copper emission, except for the operating condition of 400 degrees C at 2.00 rpm; (3) rising copper content of sludge at 600 degrees C and 2.00 rpm increased the particulate copper emission, but not the gaseous copper emission; (5) the TCLP copper leaching concentrations of sludge treated at 400 degrees C were obviously higher than those treated at 500-700 degrees C; however, all of the thermally treated products agreed with the Taiwan EPA TCLP regulations. PMID:22519084

Chou, Jing-Dong; Lin, Chiou-Liang; Hsien, Yi-Lin; Wey, Ming-Yen; Chang, Shih-Hsien

2012-01-01

220

Copper@polypyrrole nanocables  

PubMed Central

A simple hydrothermal redox reaction between microcrystalline CuOHCl and pyrrole leads to the isolation of striking nanostructures formed by polypyrrole-coated copper nanocables. These multicomponent cables that feature single-crystalline face-centered cubic Cu cores (ca. 300 nm wide and up to 200 ?m long) are smoothly coated by conducting polypyrrole, which in addition to its functionality, offers protection against oxidation of the metal core.

2012-01-01

221

Heteroleptic Copper Switches  

PubMed Central

Heteroleptic copper compounds have been designed and synthesized on solid supports. Chemical redox agents were used to change the oxidation state of the SiO2-immobilized heteroleptic copper compounds from Cu(I) to Cu(II) and then back to Cu(I). Optical spectroscopy of a dimethyl sulfoxide (DMSO) suspension demonstrated the reversibility of the Cu(I)/Cu(II) SiO2-immobilized compounds by monitoring the metal-to-ligand charge transfer (MLCT) peak at about 450 nm. EPR spectroscopy was used to monitor the isomerization of Cu(I) tetrahedral to Cu(II) square planar. This conformational change corresponds to a 90° rotation of one ligand with respect to the other. Conductive AFM (cAFM) and macroscopic gold electrodes were used to study the electrical properties of a p+ Si-immobilized heteroleptic copper compound where switching between the Cu(I)/Cu(II) states occurred at ?0.8 and +2.3 V.

Kabehie, Sanaz; Xue, Mei; Stieg, Adam Z.; Liong, Monty; Wang, Kang L.

2013-01-01

222

Direct Production of Copper  

NASA Astrophysics Data System (ADS)

The use of commercially pure oxygen in flash smelting a typical chalcopyrite concentrate or a low grade comminuted matte directly to copper produces a large excess of heat. The heat balance is controlled by adjusting the calorific value of the solid feed. A portion of the sulfide material is roasted to produce a calcine which is blended with unroasted material, and the blend is then autogeneously smelted with oxygen and flux directly to copper. Either iron silicate or iron calcareous slags are produced, both being subject to a slag cleaning treatment. Practically all of the sulfur is contained in a continuous stream of SO2 gas, most of which is strong enough for liquefaction. A particularly attractive feature of these technologies is that no radically new metallurgical equipment needs to be developed. The oxygen smelting can be carried out not only in the Inco type flash furnace but in other suitable smelters such as cyclone furnaces. Another major advantage stems from abolishion of the ever-troublesome converter aisle, which is replaced with continuous roasting of a fraction of the copper sulfide feed.

Victorovich, G. S.; Bell, M. C.; Diaz, C. M.; Bell, J. A. E.

1987-09-01

223

The pitting corrosion of copper  

SciTech Connect

Some current theories of copper pitting are contradicted by practical experience. Although it has been theorized that chloride initiates copper pitting attack, simple experiments show that the presence of chloride ion actually tends to decrease the likelihood that pitting will occur. In contrast, sulfate plays no role in pitting theory, yet sulfate has consistently demonstrated a propensity to initiate and propagate copper pitting. New theories are required to reconcile pitting theory and practical observation in order to allow the rational mitigation of copper pitting problems. In addition, the presence of natural organic matter (NOM) in water supplies prevents or inhibits certain copper corrosion problems. As a result, recent efforts to remove NOM as a means of controlling disinfection by-products may lead to increased copper corrosion problems.

Edwards, M. (Univ. of Colorado, Boulder, CO (United States). Dept. of Civil Engineering); Ferguson, J.F. (Univ. of Washington, Seattle, WA (United States). Dept. of Civil Engineering); Reiber, S.H. (HDR Engineering, Bellevue, WA (United States))

1994-07-01

224

Effect of varying iron content on the transport properties of the potassium-intercalated iron selenide KxFe2-ySe2  

NASA Astrophysics Data System (ADS)

We report the successful growth of high-quality single crystals of potassium-intercalated iron selenide KxFe2-ySe2 by the Bridgman method. The effect of iron vacancies on transport properties was investigated by electrical resistivity measurement. With varying iron content, the system passes from a semiconducting or insulating state to a superconducting state. Compared with superconductivity, the anomalous “hump” effect in the normal-state resistivity is much more sensitive to the iron deficiency. The electrical resistivity exhibits a perfect metallic behavior (R300K/R35K?42) for the sample with little iron vacancies. Our results suggest that the anomalous hump effect in the normal-state resistivity may be due to the ordering process of the cation vacancies in this nonstoichiometric compound rather than to a magnetic or structure transition. A trace of superconductivity extending up to near 44 K was also detected in some crystals of KxFe2-ySe2, which has the highest Tc of the reported iron selenides.

Wang, D. M.; He, J. B.; Xia, T.-L.; Chen, G. F.

2011-04-01

225

Spray pyrolysis of tin selenide thin-film semiconductors: the effect of selenium concentration on the properties of the thin films  

NASA Astrophysics Data System (ADS)

Thin films of tin selenide (SnxSey) with an atomic ratio of , 1 and 1.5 were prepared on a glass substrate at T = 470°C using a spray pyrolysis technique. The initial materials for the preparation of the thin films were an alcoholic solution consisting of tin chloride (SnCl4· 5H2O) and selenide acide (H2SeO3). The prepared thin films were characterized by X-ray diffraction (XRD), scanning electron microscopy, scanning tunneling microscopy, scanning helium ion microscopy, and UV-vis spectroscopy. The photoconductivity and thermoelectric effects of the SnxSey thin films were then studied. The SnxSey thin films had a polycrystalline structure with an almost uniform surface and cluster type growth. The increasing atomic ratio of r in the films, the optical gap, photosensitivity and Seebeck coefficient were changed from 1.6 to 1.37 eV, 0.01 to 0.31 and -26.2 to -42.7 mV/K (at T = 350 K), respectively. In addition, the XRD patterns indicated intensity peaks in r = 1 that corresponded to the increase in the SnSe and SnSe2 phases.

Fadavieslam, M. R.; Bagheri-Mohagheghi, M. M.

2013-08-01

226

21 CFR 73.2647 - Copper powder.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Copper powder. 73.2647 Section 73.2647...CERTIFICATION Cosmetics § 73.2647 Copper powder. (a) Identity and specifications. The color additive copper powder shall conform in identity...

2010-04-01

227

21 CFR 73.2647 - Copper powder.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Copper powder. 73.2647 Section 73.2647...CERTIFICATION Cosmetics § 73.2647 Copper powder. (a) Identity and specifications. The color additive copper powder shall conform in identity...

2009-04-01

228

21 CFR 73.2647 - Copper powder.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Copper powder. 73.2647 Section 73.2647 ...CERTIFICATION Cosmetics § 73.2647 Copper powder. (a) Identity and specifications. The color additive copper powder shall conform in identity and...

2013-04-01

229

Biological Effects of Copper and Arsenic Pollution.  

National Technical Information Service (NTIS)

Inhibitory effects of copper toward marine microorganisms were studied. Phosphate was found to prevent copper inhibition. Growth and phosphate flux kinetics were described. These phosphate limited systems were found to be copper sensitive only under condi...

D. K. Button S. S. Dunker

1971-01-01

230

Energy and Materials Flows in the Copper Industry.  

National Technical Information Service (NTIS)

The copper industry comprises both the primary copper industry, which produces 99.9%-pure copper from copper ore, and the secondary copper industry, which salvages and recycles copper-containing scrap metal to extract pure copper or copper alloys. The Uni...

L. L. Gaines

1980-01-01

231

Removal of copper from ferrous scrap  

DOEpatents

A process for removing copper from ferrous or other metal scrap in which the scrap is contacted with a polyvalent metal sulfide slag in the presence of an excess of copper-sulfide forming additive to convert the copper to copper sulfide which is extracted into the slag to provide a ratio of copper in the slag to copper in the metal scrap of at least about 10.

Blander, Milton (12833 S. 82nd Ct., Palos Park, IL 60464); Sinha, Shome N. (5748 Drexel, 2A, Chicago, IL 60637)

1990-01-01

232

Removal of copper from ferrous scrap  

DOEpatents

A process for removing copper from ferrous or other metal scrap in which the scrap is contacted with a polyvalent metal sulfide slag in the presence of an excess of copper-sulfide forming additive to convert the copper to copper sulfide which is extracted into the slag to provide a ratio of copper in the slag to copper in the metal scrap of at least about 10.

Blander, M.; Sinha, S.N.

1987-07-30

233

Electrochromism in copper oxide thin films  

Microsoft Academic Search

Transparent thin films of copper(I) oxide prepared on conductive SnO2\\/F glass substrates by anodic oxidation of sputtered copper films or by direct electrodeposition of Cu2O transformed reversibly to opaque metallic copper films when reduced in alkaline electrolyte. In addition, the same Cu2O films transform reversibly to black copper(II) oxide when cycled at more anodic potentials. Copper oxide-to-copper switching covered a

T. J. Richardson; J. L. Slack; M. D. Rubin

2001-01-01

234

Electrochromism in copper oxide thin films  

Microsoft Academic Search

Transparent thin films of copper(I) oxide prepared on conductive SnO2:F glass substrates by anodic oxidation of sputtered copper films or by direct electrodeposition of Cu2O transformed reversibly to opaque metallic copper films when reduced in alkaline electrolyte. In addition, the same Cu2O films transform reversibly to black copper(II) oxide when cycled at more anodic potentials. Copper oxide-to-copper switching covered a

T. J. Richardson; J. L. Slack; M. D. Rubin

2000-01-01

235

Removal of copper from ferrous scrap  

DOEpatents

A process for removing copper from ferrous or other metal scrap in which the scrap is contacted with a polyvalent metal sulfide slag in the presence of an excess of copper-sulfide forming additive to convert the copper to copper sulfide which is extracted into the slag to provide a ratio of copper in the slag to copper in the metal scrap of at least about 10.

Blander, M.; Sinha, S.N.

1990-05-15

236

Copper and Copper Oxide Nanoparticle Formation by Chemical Vapor Nucleation From Copper (II) Acetylacetonate  

Microsoft Academic Search

Crystalline nanometer-size copper and copper (I) oxide particle formation was studied by thermal decomposition of copper acetylacetonate Cu(acac)2 vapor using a vertical flow reactor at ambient nitrogen pressure. The experiments were performed in the precursor vapor pressure range of Pprec = 0.06 to 44 Pa at furnace temperatures of 431.5°C, 596.0°C, and 705.0°C. Agglomerates of primary particles were formed at

Albert G. Nasibulin; P. Petri Ahonen; Olivier Richard; Esko I. Kauppinen; Igor S. Altman

2001-01-01

237

Copper Artifacts: Correlation with Source Types of Copper Ores  

Microsoft Academic Search

Six out of eight minor chemical elements, determined by spectroscopic and neutron-activation techniques, were found to be critical in computing a probability that a given copper artifact was derived from one of three types of copper ore: native metal, oxidized ore, reduced ore. Two elements, gold and tin, were apparently alloyed deliberately in many artifacts from both the Old World

A. M. Friedman; M. Conway; M. Kastner; J. Milsted; D. Metta; P. R. Fields; E. Olsen

1966-01-01

238

Inborn errors of copper metabolism.  

PubMed

Two copper-transporting ATPases are essential for mammalian copper homeostasis: ATP7A, which mediates copper uptake in the gastrointestinal tract and copper delivery to the brain, and ATP7B, which mediates copper excretion by the liver into bile. Mutations in ATP7A may cause three distinct X-linked conditions in infants, children, or adolescents: Menkes disease, occipital horn syndrome (OHS), and a newly identified allelic variant restricted to motor neurons called X-linked distal hereditary motor neuropathy. These three disorders show variable neurological findings and ages of onset. Menkes disease presents in the first several months of life with failure to thrive, developmental delay, and seizures. OHS features more subtle developmental delays, dysautonomia, and connective tissue abnormalities beginning in early childhood. ATP7A-related distal motor neuropathy presents even later, often not until adolescence or early adulthood, and involves a neurological phenotype that resembles Charcot-Marie-Tooth disease, type 2. These disorders may be treatable through copper replacement or ATP7A gene therapy. In contrast, mutations in ATP7B cause a single known phenotype, Wilson disease, an autosomal recessive trait that results from copper overload rather than deficiency. Dysarthria, dystonia, tremor, gait abnormalities, and psychiatric problems may be presenting symptoms, at ages from 10 to 40 years. Excellent treatment options exist for Wilson disease, based on copper chelation. In the past 2 years (2012-2013), three new autosomal recessive copper metabolism conditions have been recognized: 1) Huppke-Brendel syndrome caused by mutations in an acetyl CoA transporter needed for acetylation of one or more copper proteins, 2) CCS deficiency caused by mutations in the copper chaperone to SODI, and 3) MEDNIK syndrome, which revealed that mutations in the ?1A subunit of adaptor protein complex 1 (AP-1) have detrimental effects on trafficking of ATP7A and ATP7B. PMID:23622398

Kaler, Stephen G

2013-01-01

239

Antimony activities in copper mattes  

NASA Astrophysics Data System (ADS)

A mass spectrometric technique combined with a double Knudsen cell was used to determine the antimony and copper activities in the Cu-Sb binary system at 1373 K and in the two-melt composition range of the Cu-S-Sb ternary system at 1423 K. The antimony and copper activities were calculated based on the intensity ration of the gaseous Sb and Cu species, over the unknown and known activity samples, respectively. ?{Sb/o} were found to be 1.1×10-2 in molten copper at 1373 K, and 1.8×10-2 and 0.44 in a copper-rich phase and in a matter phase, of the Cu-S-Sb ternary system at 1423 K, respectively. These values indicate, that antimony can be removed during the matte smelting and slagging stage of the copper smelting process. Interaction parameters of antimony in molten copper slagging stage of the copper smelting process. Interaction parameters of antimony in molten copper at 1423 K were calculated and found to be 10.7, -5.4, and 6.3 for ?{Sb/Sb} · ?Sb Sb, and ?{Sb/S}, respectively.

Hino, M.; Toguri, J. M.

1987-03-01

240

Diagnosis of Copper Transport Disorders  

PubMed Central

Techniques for the diagnosis of copper transport disorders are increasingly important due to recent recognition of previously unappreciated clinical phenotypes and emerging advances in the treatment of these conditions. Here, we collate the diagnostic approaches and techniques currently employed for biochemical and molecular assessment of at-risk individuals in whom abnormal copper metabolism is suspected.

M?ller, Lisbeth B.; Hicks, Julia D.; Holmes, Courtney S.; Goldstein, David S.; Brendl, Cornelia; Huppke, Peter; Kaler, Stephen G.

2011-01-01

241

Copper deficiency causes reversible myelodysplasia.  

PubMed

Copper deficiency is a recognized but often overlooked cause of anemia and neutropenia. We began checking serum copper levels on patients referred for evaluation for unexplained anemia and neutropenia or myelodysplasia. Eight patients were identified as copper deficient (serum copper less than 70 microg/dL). The anemia was normochromic and normocytic in seven patients. Neutropenia was present in seven patients. Seven patients had been referred for evaluation of myelodysplasia. Three were seen for consideration for allogenic stem cell transplant. Five patients had concomitant peripheral neurological symptoms. Seven patients were treated with oral copper gluconate. All treated patients demonstrated a hematological response; seven had a complete remission. The improvement in anemia and neutropenia was rapid with normalization of blood counts within three to four weeks. In one patient, normalization of the underlying marrow dysplasia was demonstrated by bone marrow histology eight months after copper replacement. The cause of copper deficiency was felt to be gastrointestinal malabsorption in five of our patients. We conclude that copper deficiency should be considered in all patients with unexplained anemia and neutropenia or myelodysplasia. PMID:17236184

Huff, Jason D; Keung, Yi-Kong; Thakuri, Mohan; Beaty, Micheal W; Hurd, David D; Owen, John; Molnár, István

2007-07-01

242

Effects of copper(II) and copper oxides on THMs formation in copper pipe.  

PubMed

Little is known about how the growth of trihalomethanes (THMs) in drinking water is affected in copper pipe. The formation of THMs and chlorine consumption in copper pipe under stagnant flow conditions were investigated. Experiments for the same water held in glass bottles were performed for comparison. Results showed that although THMs levels firstly increased in the presence of chlorine in copper pipe, faster decay of chlorine as compared to the glass bottle affected the rate of THMs formation. The analysis of water phase was supplemented by surface analysis of corrosion scales using X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and energy dispersive spectroscopy (EDX). The results showed the scales on the pipe surface mainly consisted of Cu(2)O, CuO and Cu(OH)(2) or CuCO(3). Designed experiments confirmed that the fast depletion of chlorine in copper pipe was mainly due to effect of Cu(2)O, CuO in corrosion scales on copper pipe. Although copper(II) and copper oxides showed effect on THMs formation, the rapid consumption of chlorine due to copper oxide made THM levels lower than that in glass bottles after 4h. The transformations of CF, DCBM and CDBM to BF were accelerated in the presence of copper(II), cupric oxide and cuprous oxide. The effect of pH on THMs formation was influenced by effect of pH on corrosion of copper pipe. When pH was below 7, THMs levels in copper pipe was higher as compared to glass bottle, but lower when pH was above 7. PMID:17363030

Li, Bo; Qu, Jiuhui; Liu, Huijuan; Hu, Chengzhi

2007-08-01

243

Copper: from neurotransmission to neuroproteostasis  

PubMed Central

Copper is critical for the Central Nervous System (CNS) development and function. In particular, different studies have shown the effect of copper at brain synapses, where it inhibits Long Term Potentation (LTP) and receptor pharmacology. Paradoxically, according to recent studies copper is required for a normal LTP response. Copper is released at the synaptic cleft, where it blocks glutamate receptors, which explain its blocking effects on excitatory neurotransmission. Our results indicate that copper also enhances neurotransmission through the accumulation of PSD95 protein, which increase the levels of ?-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors located at the plasma membrane of the post-synaptic density. Thus, our findings represent a novel mechanism for the action of copper, which may have implications for the neurophysiology and neuropathology of the CNS. These data indicate that synaptic configuration is sensitive to transient changes in transition metal homeostasis. Our results suggest that copper increases GluA1 subunit levels of the AMPA receptor through the anchorage of AMPA receptors to the plasma membrane as a result of PSD-95 accumulation. Here, we will review the role of copper on neurotransmission of CNS neurons. In addition, we will discuss the potential mechanisms by which copper could modulate neuronal proteostasis (“neuroproteostasis”) in the CNS with focus in the Ubiquitin Proteasome System (UPS), which is particularly relevant to neurological disorders such as Alzheimer’s disease (AD) where copper and protein dyshomeostasis may contribute to neurodegeneration. An understanding of these mechanisms may ultimately lead to the development of novel therapeutic approaches to control metal and synaptic alterations observed in AD patients.

Opazo, Carlos M.; Greenough, Mark A.; Bush, Ashley I.

2014-01-01

244

Copper chip technology  

NASA Astrophysics Data System (ADS)

Recently, IBM announced the first silicon integrated circuit technology that incorporates copper on-chip wiring. This technology, which combines industry-leading CMOS ULSI devices with 6 levels of hierarchically-scaled Cu metallization, has reached the point of manufacturing, after passing the qualification tests required to prove feasibility, yield, reliability, and manufacturability. The discussion of the change from Al to Cu interconnects for ULSI encompasses a wide variety of issues. This paper attempts to address these by way of example, from the broad range of detailed studies that have been performed in the course of developing these so-called 'copper chips'. Motivational issues are covered by comparative modeling of performance aspects and cost. The technology parameters and features are shown, as well as data relating to the process integration, electrical yield and parametric behavior, early manufacturing data, high-frequency modeling and measurements, nose and clock skew. The viability of this technology is indicated by results from reliability stressing, as well as the first successful demonstrations of fully functional SRAM, DRAM, and microprocessor chips with Cu wiring. The advantages of integrated Cu wiring may be applied even more broadly in the future. An example shown here is the achievement of very high-quality integrated inductors; these may help prospects for complete integration of RF and wireless communications chips onto silicon.

Edelstein, Daniel C.

1998-08-01

245

Copper oxide nanocrystals.  

PubMed

It is well-known that inorganic nanocrystals are a benchmark model for nanotechnology, given that the tunability of optical properties and the stabilization of specific phases are uniquely possible at the nanoscale. Copper (I) oxide (Cu(2)O) is a metal oxide semiconductor with promising applications in solar energy conversion and catalysis. To understand the Cu/Cu(2)O/CuO system at the nanoscale, we have developed a method for preparing highly uniform monodisperse nanocrystals of Cu(2)O. The procedure also serves to demonstrate our development of a generalized method for the synthesis of transition metal oxide nanocrystals. Cu nanocrystals are initially formed and subsequently oxidized to form highly crystalline Cu(2)O. The volume change during phase transformation can induce crystal twinning. Absorption in the visible region of the spectrum gave evidence for the presence of a thin, epitaxial layer of CuO, which is blue-shifted, and appears to increase in energy as a function of decreasing particle size. XPS confirmed the thin layer of CuO, calculated to have a thickness of approximately 5 A. We note that the copper (I) oxide phase is surprisingly well-stabilized at this length scale. PMID:15984877

Yin, Ming; Wu, Chun-Kwei; Lou, Yongbing; Burda, Clemens; Koberstein, Jeffrey T; Zhu, Yimei; O'Brien, Stephen

2005-07-01

246

Effects of copper(II) and copper oxides on THMs formation in copper pipe  

Microsoft Academic Search

Little is known about how the growth of trihalomethanes (THMs) in drinking water is affected in copper pipe. The formation of THMs and chlorine consumption in copper pipe under stagnant flow conditions were investigated. Experiments for the same water held in glass bottles were performed for comparison. Results showed that although THMs levels firstly increased in the presence of chlorine

Bo Li; Jiuhui Qu; Huijuan Liu; Chengzhi Hu

2007-01-01

247

A comparison of the wettability of copper-copper oxide and silver-copper oxide on polycrystalline alumina  

Microsoft Academic Search

The contact angles of liquid silver-copper oxide\\/alumina and liquid copper-copper oxide\\/alumina systems were determined using the sessile drop method. Copper oxide (CuO) additions of 1.5–10.0 wt% were made. Temperatures of 970–1250 °C for the silver-based alloys and 1090–1300 °C for the copper-based alloys were studied. Minimum contact angles of 42±8 and 64±7 ° were obtained for the copper-copper oxide alloys

A. M. Meier; Pr. Chidambaram; G. R. Edwards

1995-01-01

248

Copper chaperones. The concept of conformational control in the metabolism of copper.  

PubMed

Copper chaperones compose a specific class of proteins assuring safe handling and specific delivery of potentially harmful copper ions to a variety of essential copper proteins. Copper chaperones are structurally heterogeneous and can exist in multiple metal-loaded as well as oligomeric forms. Moreover, many copper chaperones can exist in various oxidative states and participate in redox catalysis, connected with their functioning. This review is focused on the analysis of the structural and functional properties of copper chaperones and their partners, which allowed us to define specific regulatory principles in copper metabolism connected with copper-induced conformational control of copper proteins. PMID:23684646

Palumaa, Peep

2013-06-27

249

Synthesis and characterisation of Copper Zinc Tin Sulphide (CZTS) compound for absorber material in solar-cells  

NASA Astrophysics Data System (ADS)

The development of thin-film semiconductor compounds, such as Copper Indium Gallium Selenide (CIGS), has caused remarkable progress in the field of thin-film photovoltaics. However, the scarcity and the increasing prices of indium impose the hunt for alternative materials. The Copper Zinc Tin Sulphide (CZTS) is one of the promising emerging materials with Kesterite-type crystal structure and favourable material properties like high absorption co-efficient and direct band-gap. Moreover, all the constituent elements of CZTS are non-toxic and aplenty on the earth-crust, making it a potential candidate for the thin-film photovoltaics. Here we report the synthesis of CZTS powder from its constituent elements, viz. copper, zinc, tin and sulphur, in an evacuated Quartz ampoule at 1030 K temperature. The sulphur content in the raw mixture in the ampoule was varied and optimised in order to attain the desired atomic stoichiometry of the compound. The synthesised powder was characterised by X-Ray diffraction technique (XRD), Raman Scattering Spectroscopy, Energy Dispersive Analysis of X-Ray (EDAX) and UV-Visible Absorption Spectra. The XRD Patterns of the synthesised compound show the preferred orientation of (112), (220) and (312) planes, confirming the Kesterite structure of CZTS. The chemical composition of the powder was analysed by EDAX and shows good atomic stoichiometry of the constituent elements in the CZTS compound. The UV-Vis absorption spectra confirm the direct band-gap of about 1.45 eV, which is quite close to the optimum value for the semiconductor material as an absorber in solar-cells.

Kheraj, Vipul; Patel, K. K.; Patel, S. J.; Shah, D. V.

2013-01-01

250

Metabolism and functions of copper in brain.  

PubMed

Copper is an important trace element that is required for essential enzymes. However, due to its redox activity, copper can also lead to the generation of toxic reactive oxygen species. Therefore, cellular uptake, storage as well as export of copper have to be tightly regulated in order to guarantee sufficient copper supply for the synthesis of copper-containing enzymes but also to prevent copper-induced oxidative stress. In brain, copper is of importance for normal development. In addition, both copper deficiency as well as excess of copper can seriously affect brain functions. Therefore, this organ possesses ample mechanisms to regulate its copper metabolism. In brain, astrocytes are considered as important regulators of copper homeostasis. Impairments of homeostatic mechanisms in brain copper metabolism have been associated with neurodegeneration in human disorders such as Menkes disease, Wilson's disease and Alzheimer's disease. This review article will summarize the biological functions of copper in the brain and will describe the current knowledge on the mechanisms involved in copper transport, storage and export of brain cells. The role of copper in diseases that have been connected with disturbances in brain copper homeostasis will also be discussed. PMID:24440710

Scheiber, Ivo F; Mercer, Julian F B; Dringen, Ralf

2014-05-01

251

49 CFR 192.279 - Copper pipe.  

Code of Federal Regulations, 2013 CFR

...Transportation 3 2013-10-01 2013-10-01 false Copper pipe. 192.279 Section 192.279 Transportation...of Materials Other Than by Welding § 192.279 Copper pipe. Copper pipe may not be threaded except that copper...

2013-10-01

252

Thermoelectric power of homovalent copper alloys. (Oxidation)  

Microsoft Academic Search

An oxidation technique has been used to remove traces of iron from copper-gold and copper-silver alloys and the low temperature thermoelectric power of these homovalent copper alloys has been used to study the success of the oxidation procedure. The electron diffusion and phonon drag contributions to thermoelectric power characteristic to the scattering from silver and gold impurities in copper are

A. M. Guenault

1974-01-01

253

The Role of Copper in Tumour Angiogenesis  

Microsoft Academic Search

Copper stimulates the proliferation and migration of endothelial cells and is required for the secretion of several angiogenic factors by tumour cells. Copper chelation decreases the secretion of many of these factors. Serum copper levels are upregulated in many human tumours and correlate with tumour burden and prognosis. Copper chelators reduce tumour growth and microvascular density in animal models. New

Sarah A. Lowndes; Adrian L. Harris

2005-01-01

254

Thermal dissociation of intercalated titanium selenides Fe x TiSe2 ( x = 0.10, 0.25, 0.50)  

NASA Astrophysics Data System (ADS)

Using static tensimetry, the selenium pressure during dissociation of intercalated compounds Fe x TiSe2 has been measured in a temperature range of stability of the homogeneous material and in the region of decomposition caused by thermal expansion of the polaron band. It has been shown that covalent centers in the stability region of the homogeneous state, which are stabilized by the polaron state of conduction electrons, behave as the effective oxidants lowering the Fermi level. Broadening of the polaron band in the region of a high iron concentration leads to weakening the oxidizing influence of polarons. Iron selenides are formed during the decomposition of intercalated compounds, which leads to an essential non-quasi-binarity of the Fe-TiSe2 system.

Titov, A. N.; Zelenina, L. N.; Chusova, T. P.; Shkvarina, E. G.

2012-12-01

255

Ternary lanthanum sulfide selenides ?-LaS 2- xSe x (0< x<2) with mixed dichalcogenide anions X22- ( X=S, Se)  

NASA Astrophysics Data System (ADS)

Mixed lanthanum sulfide selenides LaS 2- xSe x (0< x<2) were obtained by metathesis reactions starting from anhydrous lanthanum chloride and alkali metal polychalcogenides. The LaS 2- xSe x compounds crystallize in space group P2 1/ a, no. 14, and adopt the ?- LnS 2 ( Ln=Y, La-Lu ) structure type with a pronounced site preference for the chalcogen atoms. The mixed chalcogenides form a complete miscible series with lattice parameters a=820-849 pm, b=413-425 pm and c=822-857 pm ( ??90°) following Vegard's rule. Raman signals indicate the presence of mixed X22- dianions, a species rarely evidenced in literature, besides the well known anions S 22- and Se 22-. The band gaps of the LaS 2- xSe x compounds, determined by optical spectroscopy, decrease nearly linearly with increasing amount of selenium.

Bartsch, Christian; Doert, Thomas

2012-01-01

256

GPx-Like activity of selenides and selenoxides: experimental evidence for the involvement of hydroxy perhydroxy selenane as the active species.  

PubMed

The reaction mechanism of the GPx-like oxidation of PhSH with H(2)O(2) catalyzed by selenoxides proceeds via formation of the hydroxy perhydroxy selenane, which is a stronger oxidizing agent than selenoxide. A hydroxy perhydroxy selenane intermediate was observed by electrospray ionization mass spectrometry and (77)Se NMR spectroscopy in reactions of selenoxide 8 with H(2)O(2).The initial velocity of oxidation of PhSH by H(2)O(2) with selenoxide 8 is 4 orders of magnitude higher than that of 8 without peroxide. Selenoxide 8 is not reduced to selenide 6 by PhSH in the presence of H(2)O(2). While electronic substituent effects have minimal impact on the catalytic performance of selenoxides, chelating groups increase the rate of catalysis. PMID:22136421

Nascimento, Vanessa; Alberto, Eduardo E; Tondo, Daniel W; Dambrowski, Daniel; Detty, Michael R; Nome, Faruk; Braga, Antonio L

2012-01-11

257

NID Copper Sample Analysis  

SciTech Connect

The current focal point of the nuclear physics program at PNNL is the MAJORANA DEMONSTRATOR, and the follow-on Tonne-Scale experiment, a large array of ultra-low background high-purity germanium detectors, enriched in 76Ge, designed to search for zero-neutrino double-beta decay (0???). This experiment requires the use of germanium isotopically enriched in 76Ge. The MAJORANA DEMONSTRATOR is a DOE and NSF funded project with a major science impact. The DEMONSTRATOR will utilize 76Ge from Russia, but for the Tonne-Scale experiment it is hoped that an alternate technology, possibly one under development at Nonlinear Ion Dynamics (NID), will be a viable, US-based, lower-cost source of separated material. Samples of separated material from NID require analysis to determine the isotopic distribution and impurities. DOE is funding NID through an SBIR grant for development of their separation technology for application to the Tonne-Scale experiment. The Environmental Molecular Sciences facility (EMSL), a DOE user facility at PNNL, has the required mass spectroscopy instruments for making isotopic measurements that are essential to the quality assurance for the MAJORANA DEMONSTRATOR and for the development of the future separation technology required for the Tonne-Scale experiment. A sample of isotopically separated copper was provided by NID to PNNL in January 2011 for isotopic analysis as a test of the NID technology. The results of that analysis are reported here. A second sample of isotopically separated copper was provided by NID to PNNL in August 2011 for isotopic analysis as a test of the NID technology. The results of that analysis are also reported here.

Kouzes, Richard T.; Zhu, Zihua

2011-09-12

258

Origins of biliary copper.  

PubMed

We tested the hypothesis that the copper present in bile--the major route of elimination of the metal from the body--is derived exclusively from hepatocytes by administering radiocopper (64Cu or 67Cu)-labeled ionic Cu, desialylated (AsCPN) or intact human ceruloplasmin (CPN), intravenously, to rats with cannulated bile ducts. The rates of appearance and the total amounts of radiolabeled isotope recovered in bile were measured. The three vehicles chosen for the delivery of radiocopper interact differently with hepatocytes: ionic Cu is taken up by a passive process (Schmitt, R. C. et al., Am. J. Physiol. 1983; 244:G183-G191); AsCPN is promptly cleared from the circulation by specific receptor-mediated endocytosis, and CPN largely remains in the circulation for the duration of the experiment. Similar amounts of radiocopper were recovered following injections of ionic Cu (3.1%) or CPN (2%), but substantially larger amounts (8.1%) were excreted after administration of AsCPN. Using an antibody to CPN which reacts also with AsCPN, we found about 70% of the bile radioactivity to be immunoprecipitable following injections of either glycoprotein, indicating that a fraction of these copper proteins had entered the bile essentially unmodified. Our observations indicate that in addition to the lysosomal compartment which catabolizes a portion of the AsCPN in hepatocytes, there appears to be a direct route for AsCPN from hepatocellular sinusoids to the bile canaliculi. Since CPN does not interact significantly with hepatocytes, its presence in bile suggests transcytosis via the biliary epithelium. PMID:6479854

Kressner, M S; Stockert, R J; Morell, A G; Sternlieb, I

1984-01-01

259

Arsenic activities in molten copper and copper sulfide melts  

Microsoft Academic Search

In recent years, the concentration of the group Va elements such as arsenic, antimony, and bismuth has been increasing in\\u000a copper concentrates. The elimination and recovery of these elements during the copper smelting process have presented serious\\u000a problems. While the distribution of minor elements has been studied extensively, very little knowledge exists on the activities\\u000a of these minor elements in

M. Hino; J. M. Toguri

1986-01-01

260

Energy and materials flows in the copper industry  

Microsoft Academic Search

The copper industry comprises both the primary copper industry, which produces 99.9%-pure copper from copper ore, and the secondary copper industry, which salvages and recycles copper-containing scrap metal to extract pure copper or copper alloys. The United States uses about 2 million tons of copper annually, 60% of it for electrical applications. Demand is expected to increase less than 4%

Gaines

1980-01-01

261

Copper chaperones, intracellular copper trafficking proteins. Function, structure, and mechanism of action.  

PubMed

This review summarizes findings on a new family of small cytoplasmic proteins called copper chaperones. The copper chaperones bind and deliver copper ions to intracellular compartments and insert the copper into the active sites of specific partners, copper-dependent enzymes. Three types of copper chaperones have been found in eukaryotes. Their three-dimensional structures have been determined, intracellular target proteins identified, and mechanisms of action have been revealed. The Atx1 copper chaperone binds Cu(I) and interacts directly with the copper-binding domains of a P-type ATPase copper transporter, its physiological partner. The copper chaperone CCS delivers Cu(I) to Cu,Zn-superoxide dismutase 1. Cox17 and Cox11 proteins serve as copper chaperones for cytochrome c oxidase, a copper-dependent enzyme. PMID:12948382

Markossian, K A; Kurganov, B I

2003-08-01

262

Use of Cement Copper in an Iron-Copper-Carbon Powder Metallurgy Alloy.  

National Technical Information Service (NTIS)

An investigation was made of the substitution of cement copper powder for commercial copper powder in an Fe-7 pct Cu-1 pct C powder metallurgy alloy. Copper powders from six different commercial cementation operations were separately upgraded by screening...

R. L. Crosby D. H. Desy R. M. Doerr

1970-01-01

263

21 CFR 73.1125 - Potassium sodium copper chloropyhllin (chlorophyllin-copper complex).  

Code of Federal Regulations, 2010 CFR

...chloropyhllin (chlorophyllin-copper complex). (a) Identity...color additive potassium sodium copper chlorophyllin is a green to black powder obtained from chlorophyll...replacing the magnesium with copper. The source of the...

2009-04-01

264

21 CFR 73.1125 - Potassium sodium copper chloropyhllin (chlorophyllin-copper complex).  

Code of Federal Regulations, 2010 CFR

...chloropyhllin (chlorophyllin-copper complex). (a) Identity...color additive potassium sodium copper chlorophyllin is a green to black powder obtained from chlorophyll...replacing the magnesium with copper. The source of the...

2010-04-01

265

Tri- and tetracoordinate copper(I) complexes bearing bidentate soft/hard SN and SeN ligands based on 2-aminopyridine.  

PubMed

The coordination properties of the EN ligands N-(2-pyridinyl)amino-diphenylphosphine sulfide, N-(2-pyridinyl)amino-diisopropylphosphine sulfide, N-(2-pyridinyl)amino-diphenylphosphine selenide, N-(2-pyridinyl)amino-diisopropylphosphine selenide towards copper(I) precursors CuX (X = Br, I), [Cu(IPr)Cl] (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene), and [Cu(CH(3)CN)(4)]PF(6) were studied. Treatment of CuX with EN ligands resulted in the formation of tricoordinate complexes of the type [Cu(?(2)(E,N)-EN)X]. The reaction of [Cu(IPr)Cl] with EN ligands, followed by halide abstraction with AgSbF(6), afforded cationic tricoordinate complexes [Cu(?(2)(S,N)-EN)(IPr)](+), while the reaction of [Cu(CH(3)CN)(4)](+) with two equivalents of EN ligands yielded tetrahedral complexes [Cu(?(2)(E,N)-EN)(2)](+). Halide removal from [Cu(?(2)(S,N)-SN)I] with silver salts in the presence of L = CH(3)CN and CNtBu afforded dinuclear complexes of the type [Cu(?(2)(S,N),?(S)-SN)(L)](2)(2+) containing bridging SN ligands. With the terminal alkynes HC?CC(6)H(4)Me and HC?CC(6)H(4)OMe, complexes of the formula [Cu(?(2)(S,N)-SN-iPr)(?(2)-HC?CC(6)H(4)Me)](+) and [Cu(?(2)(S,N)-SN-iPr)(?(2)-HC?CC(6)H(4)OMe)](+) were obtained. The mononuclear nature of these compounds was supported by DFT calculations. Most complexes were also characterized by X-ray crystallography. PMID:21647495

Öztopcu, Özgür; Mereiter, Kurt; Puchberger, Michael; Kirchner, Karl A

2011-07-14

266

Majorana Electroformed Copper Mechanical Analysis  

SciTech Connect

The MAJORANA DEMONSTRATOR is a large array of ultra-low background high-purity germanium detectors, enriched in 76Ge, designed to search for zero-neutrino double-beta decay. The DEMONSTRATOR will utilize ultra high purity electroformed copper for a variety of detector components and shielding. A preliminary mechanical evaluation was performed on the Majorana prototype electroformed copper material. Several samples were removed from a variety of positions on the mandrel. Tensile testing, optical metallography, scanning electron microscopy, and hardness testing were conducted to evaluate mechanical response. Analyses carried out on the Majorana prototype copper to this point show consistent mechanical response from a variety of test locations. Evaluation shows the copper meets or exceeds the design specifications.

Overman, Nicole R.; Overman, Cory T.; Kafentzis, Tyler A.; Edwards, Danny J.; Hoppe, Eric W.

2012-04-30

267

Copper Hydroxide as a Repellent.  

National Technical Information Service (NTIS)

The invention disclosed and claimed herein provides an environmentally safe, economical means to reduce bird predation by coating seeds and plants with copper hydroxide. The active agent used in the invention is presently used as a fungicide. The particul...

M. L. Avery D. G. Decker

1991-01-01

268

Antimony activities in copper mattes  

Microsoft Academic Search

A mass spectrometric technique combined with a double Knudsen cell was used to determine the antimony and copper activities\\u000a in the Cu-Sb binary system at 1373 K and in the two-melt composition range of the Cu?S?Sb ternary system at 1423 K. The antimony\\u000a and copper activities were calculated based on the intensity ration of the gaseous Sb and Cu species,

M. Hino; J. M. Toguri

1987-01-01

269

Accelerated Testing of Copper Corrosion  

Microsoft Academic Search

An innovative, short-term corrosion test has been developed that can predict long-term copper corrosion behavior. When used in a six-day study of uniform copper corrosion in five waters, the test predicted corrosion rates that were in good qualitative and quantitative agreement with known long-term (210-day) results. A second phase of the study examined the poorly understood phenomenon of soft-water pitting.

Marc Edwards; John F. Ferguson

1993-01-01

270

Occupational genotoxicity among copper smelters.  

PubMed

Occupational exposure in a copper smelting industry may produce various adverse health effects including cancer. Despite a number of well-documented studies reporting an increased risk of cancer among copper smelter workers, the data on genotoxic effects in this industry are scarce. In view of the above, an assessment of DNA damage in peripheral blood leukocytes by Comet assay from copper smelter workers was undertaken. Additionally, the proton-induced X-ray emission (PIXE) analysis was assessed to determine the metal content of samples. The study was conducted with all workers from a copper smelter (males; n = 11), and a control group (n = 11) was recruited. The results of our study showed a significant increase (p < 0.001; Mann-Whitney test) in DNA damage in peripheral blood lymphocytes of smelter workers, compared to the controls (p < 0.001; Mann-Whitney test). No correlation between DNA damage or metal concentration and age mean or time of exposure was found under study. Our findings indicate that copper smelter workers have increased levels of DNA damage in somatic cells, suggesting a potential health risk for the workers. PIXE results show the presence of copper, iron, and other metals. PMID:22042770

De Olivera, Juliana Viégas Duarte; Boufleur, Liana Appel; Dos Santos, Carla Eliete Iochims; Dias, Johnny Ferraz; Squeff, Cíntia Haag; Silva, Guilherme Ruivo Gonçalves; Ianistcki, Martus; Benvegnú, Vinícius Cosmos; Da Silva, Juliana

2012-10-01

271

Porins Increase Copper Susceptibility of Mycobacterium tuberculosis  

PubMed Central

Copper resistance mechanisms are crucial for many pathogenic bacteria, including Mycobacterium tuberculosis, during infection because the innate immune system utilizes copper ions to kill bacterial intruders. Despite several studies detailing responses of mycobacteria to copper, the pathways by which copper ions cross the mycobacterial cell envelope are unknown. Deletion of porin genes in Mycobacterium smegmatis leads to a severe growth defect on trace copper medium but simultaneously increases tolerance for copper at elevated concentrations, indicating that porins mediate copper uptake across the outer membrane. Heterologous expression of the mycobacterial porin gene mspA reduced growth of M. tuberculosis in the presence of 2.5 ?M copper by 40% and completely suppressed growth at 15 ?M copper, while wild-type M. tuberculosis reached its normal cell density at that copper concentration. Moreover, the polyamine spermine, a known inhibitor of porin activity in Gram-negative bacteria, enhanced tolerance of M. tuberculosis for copper, suggesting that copper ions utilize endogenous outer membrane channel proteins of M. tuberculosis to gain access to interior cellular compartments. In summary, these findings highlight the outer membrane as the first barrier against copper ions and the role of porins in mediating copper uptake in M. smegmatis and M. tuberculosis.

Speer, Alexander; Rowland, Jennifer L.; Haeili, Mehri; Niederweis, Michael

2013-01-01

272

CVD of copper using copper(I) and copper(II) ?-diketonates  

Microsoft Academic Search

Reaction paths for the chemical vapor deposition (CVD) of copper from (hfac)Cu(vtms), Cu(hfac)2, and Cu(fod)2 were studied using mass spectrometric analysis of the reaction products. Cu(hfac)2 was identified as one of the products when (hfac)Cu(vtms) reacts with or without hydrogen at temperatures from 130 to 235 °C in a hot-wall batch reactor. Therefore, the route to copper formation is a

Mehul B. Naik; William N. Gill; Robert H. Wentorf; Robert R. Reeves

1995-01-01

273

BTA copper complexes.  

PubMed

Cupric oxide is one of the most important additives used (a) to catalyze decomposition reactions in gas generators to obtain cooler reaction gases, (b) as burning enhancer for ammonium perchlorate-based composite propellants, and (c) as coloring agent in pyrotechnics. In this context, the reaction of Cu(2+) ions in aqueous ammonia solution with bis(tetrazolyl)amine (H(2)bta) was investigated. Depending on the reaction conditions three complexes were obtained: Cu(bta)(NH(3))(2) (1), Cu(bta)(NH(3))(2).H(2)O (2), and (NH(4))(2)Cu(bta)(2).2.5H(2)O (3). The crystal structures of 1 and 2 are discussed with respect to the coordination mode of the dianion of N,N-bis(1(2)H-tetrazol-5-yl)-amine (bta), which mediates in the case of 1 and 2 weak superexchange interactions between the adjacent magnetic transition-metal Cu(II) cations. These antiferromagnetic interactions result from 1D copper chains over an hidden azide end-to-end bridge. Interestingly, the structural arrangement of 1 completely changes in the presence of crystal-bound water. Moreover, some physicochemical properties (e.g., heat of formation, friction, and impact sensitivity, DSC) of these complexes with respect to high-energetic materials are discussed. PMID:16241154

Friedrich, Manfred; Gálvez-Ruiz, Juan Carlos; Klapötke, Thomas M; Mayer, Peter; Weber, Birgit; Weigand, Jan J

2005-10-31

274

Copper ferrite revisited  

NASA Astrophysics Data System (ADS)

Reinvestigation of the Jahn-Teller distortion of the copper ferrospinel has established that the critical number of octahedral-site Cu 2+ ions per formula unit for a cooperative distortion to tetragonal symmetry at room temperature is ca 0.8. Several anomalies associated with the tetragonal-cubic transition have been noted in the literature; these anomalies are shown to reflect not only a tendency for segregation into Cu-rich and Cu-poor regions in the neighborhood of Tt, but also a quenching in of both tetrahedral-site Cu 2+ and oxygen vacancies on rapid cooling. The intersite exchange Cu 2+A + Fe 3+B = Cu 2+B + Fe 3+A to reestablish equilibrium becomes facile near 250°C; reoxidation becomes facile near 325°C. This temperature resolution of the two processes in quenched samples is reflected in the temperature variation of the {c}/{a} ratio and the electrical resistance below Tt; these variations can be interpreted in terms of variations in the octahedral-site Cu 2+ concentration and the associated splitting of the Fe 3+B and Cu +B energies.

Tang, Xiao-Xia; Manthiram, A.; Goodenough, J. B.

1989-04-01

275

Genes involved in copper resistance influence survival of Pseudomonas aeruginosa on copper surfaces  

PubMed Central

Aims To evaluate the killing of Pseudomonas aeruginosa PAO1 on copper cast alloys and the influence of genes on survival on copper containing medium and surfaces. Methods and Results Different strains of P. aeruginosa were inoculated on copper containing medium or different copper cast alloys and the survival rate determined. The survival rates were compared to rates on copper-free medium and stainless steel as control. In addition, the effect of temperature on survival was examined. Conclusions Copper cast alloys had previously shown to be bactericidal to various bacteria but the mechanism of copper-mediated killing is still not known. In this report we demonstrate that P. aeruginosa PAO1 is rapidly killed on different copper cast alloys and that genes involved in conferring copper resistance in copper-containing medium also influenced survival on copper cast alloys. We also show that the rate of killing is influenced by temperature.

Elguindi, Jutta; Wagner, Janine; Rensing, Christopher

2013-01-01

276

Copper metabolism in retinitis pigmentosa patients.  

PubMed Central

Serum copper, ceruloplasmin, and urinary copper were estimated in 13 normal subjects and 24 patients with primary retinitis pigmentosa. The serum copper levels in patients appeared to be higher and ceruloplasmin levels lower than in the normal subjects. The patients seem to fall into 2 categories with regard to urinary copper. About a third of them excreted 2-4 times more copper in the urine, while in the others the excretion is comparable to normal subjects. It appears possible that there exists in India a genetic isolate of retinitis pigmentosa with altered copper metabolism. The distribution of these patients may be different between the northern and southern parts of the country.

Rao, S S; Satapathy, M; Sitaramayya, A

1981-01-01

277

Process Of Bonding Copper And Tungsten  

DOEpatents

Process for bonding a copper substrate to a tungsten substrate by providing a thin metallic adhesion promoting film bonded to a tungsten substrate and a functionally graded material (FGM) interlayer bonding the thin metallic adhesion promoting film to the copper substrate. The FGM interlayer is formed by sintering a stack of individual copper and tungsten powder blend layers having progressively higher copper content/tungsten content, by volume, ratio values in successive powder blend layers in a lineal direction extending from the tungsten substrate towards the copper substrate. The resulting copper to tungsten joint well accommodates the difference in the coefficient of thermal expansion of the materials.

Slattery, Kevin T. (St. Charles, MO); Driemeyer, Daniel E. (Manchester, MO); Davis, John W. (Ballwin, MO)

2000-07-18

278

Reactivity studies of plasma-synthesized aluminum trifluoride and electrochemical synthesis of non-stoichiometric silver selenide nanowire arrays  

NASA Astrophysics Data System (ADS)

A high surface area aluminum trifluoride material ("plasma-AIF3 ") has previously been synthesized in our laboratory by decomposition of zeolitic precursors in fluorine-containing, low-temperature plasmas. The characterization of the halogen exchange reactivity of this unique fluoride material is presented in Part 1 of the dissertation. A gas flow reactor was designed and built to study the isothermal and temperature-dependent halogen exchange activity of plasma-AIF3, with comparisons being made to the well-known halogen exchange catalyst beta-AIF3. Isothermal experiments showed that plasma-AIF3 is an active halogen exchange catalyst for the dismutation of dichlorodifluoromethane, while temperature-programmed reaction (TPR) experiments revealed a lower temperature onset of activity with plasma-AIF3 when compared to beta-AIF3. The existence of two distinct active sites for halogen exchange on aluminum fluoride is proposed, with sites characteristic of plasma-AIF3 and R-AIF3 having lower and higher temperature onsets of activity, respectively. TPR data for hydrated plasma-AIF3 showed a significant attenuation of the lower temperature active sites, while the higher temperature site remained relatively unchanged in activity. Temperature-programmed X-ray diffraction of plasma-AIF3 revealed the existence of beta-AIF 3 crystallites at temperatures between 225 and 500°C, thus rationalizing the existence of the higher temperature active site (associated with beta-AIF 3) in plasma-AIF3 during heating. Plasma-AIF3 also displayed a high affinity for crystalline hydrate formation with extended exposure to moist air, and TPR experiments performed on commercially available AIF3·3H2O produced plots similar in shape and features when compared to plasma-AIF3. The thermal transformation processes of the trihydrate suggest the origin of the lower temperature active site to be associated with an amorphous bulk AIF3 structure. Part 2 of the dissertation summarizes the current efforts made toward the template-assisted electrodeposition of Ag2+deltaSe nanowire arrays for fundamental and exploratory studies of the magnetoresistance in non-stoichiometric silver chalcogenides. Silver selenide can be difficult to electrodeposit due in part to the highly facile plating of silver metal from aqueous solutions. A new electrodeposition solution is proposed, containing AgNO3 and SeCl4 as the metal precursors, dimethyl sulfoxide (DMSO) as the solvent and tetrabutylammonium chloride (TBACl) as a supporting electrolyte. The electrodeposition of Ag2Se from this solution and a previously reported solution using NaNO3 as supporting electrolyte was investigated using cyclic voltammetry and X-ray diffraction analysis of electrodeposited thin films. Cyclic voltammograms of solutions containing only AgNO3 and TBACl in DMSO showed one redox couple corresponding to the deposition and stripping of Ag metal, while the NaNO3-based solution showed an additional redox couple believed to involve the generation of negatively-charged Ag nanoparticles. Thin film electrodeposition of Ag metal from DMSO-based solutions produced non-dendritic deposits, and may be a useful alternative bath solvent for the silver plating industry. Solutions containing only SeCl 4 and TBACl in DMSO were studied by cyclic voltammetry, and revealed important potential ranges within which elemental Se is stable with respect to oxidation and reduction. The proposed mixed-metal electrodeposition solution was also analyzed with cyclic voltammetry, and the reductive formation of Ag2Se was found to occur at potentials between -0.55 V and -0.70 V (vs. Pt/0.1 M Nal, 0.05 M I2 (DMSO)). Using the results from the electroanalysis of the electrodeposition solutions, nanowire arrays of Ag2+deltaSe were successfully grown by electrodeposition into porous alumina membranes at room temperature (22°C) using an applied voltage of -0.70 V (vs. Pt/0.1 M Nal, 0.05 M I2 (DMSO)). Scanning electron microscopy showed smooth and continuous nanowires of 50 and 100 nm diameters and up to lengths of 25 mum. Electro

Hajime, Evan Koon Lun Yuuji

279

Clustering and Precipitation in Neutron Irradiated Low Copper and Copper-free Steels and Model Alloys  

Microsoft Academic Search

The role of copper in the embrittlement of A533B and related steels used as the pressure vessels of nuclear reactors has been the subject of numerous atom probe investigations. As copper is deleterious to the mechanical properties of these neutron irradiated steels, some copper-free and low copper alloys have been investigated with the local electrode atom probe to ascertain if

G. R. Odette; M. K. Miller; K. F. Russell

2006-01-01

280

Copper and anesthesia: clinical relevance and management of copper related disorders.  

PubMed

Recent research has implicated abnormal copper homeostasis in the underlying pathophysiology of several clinically important disorders, some of which may be encountered by the anesthetist in daily clinical practice. The purpose of this narrative review is to summarize the physiology and pharmacology of copper, the clinical implications of abnormal copper metabolism, and the subsequent influence of altered copper homeostasis on anesthetic management. PMID:23762044

Langley, Adrian; Dameron, Charles T

2013-01-01

281

Formation of copper chromite in chrome — Magnesite refractories during service in copper-smelters  

Microsoft Academic Search

Conclusions Copper chromite in chrome — magnesite refractories during service in copper-smelting units can form both on account of free copper oxide separating from the natural chromite without decomposition of the remaining solid solution, and also as a result of the decomposition of the original chromite during its reaction with a mixture of copper oxides and silica with the formation

V. M. Ust'yantsev; V. P. Mar'evich; V. A. Perepelitsyn

1971-01-01

282

Copper Recovery from Primary Smelter Dusts.  

National Technical Information Service (NTIS)

The Bureau of Mines researched methods for recovering copper from cyclone and electrostatic-precipitator dusts of primary copper smelters as part of its program to maximize minerals and metals recovery from primary and secondary domestic resources. Small-...

W. E. Anable J. I. Paige D. L. Paulson

1981-01-01

283

Control of Copper Smelter Fugitive Emissions.  

National Technical Information Service (NTIS)

This report deals with fugitive emissions from copper smelting and with related emission control measures. The study involved evaluation of the controls now used in the copper smelting industry and development of suggestions for alternative control device...

T. W. Devitt

1980-01-01

284

Impact of copper deficiency in humans.  

PubMed

Humans consume about 1 mg of copper daily, an amount thought adequate for most needs. Genetic, environmental, or physiological alterations can impose a higher copper set point, increasing risk for copper-limited pathophysiology. Humans express about a dozen proteins that require copper for function (cuproenzymes). Limitation in the activity of cuproenzymes can explain the pleiotropic effect of copper deficiency. However, for most of the salient features of human copper deficiency, the precise molecular mechanisms are unknown. This is true for the two most common clinical features, hypochromic anemia and adult onset peripheral neuropathy/ataxia, a condition described frequently in the last decade due to multiple etiologies. The challenge for future scientists will be to identify the mechanisms underlying the pathophysiology of copper deficiency so appropriate screening and treatment can occur. The need for a strong copper biomarker to aid in this screening is critical. PMID:24517364

Prohaska, Joseph R

2014-05-01

285

Leaching of Copper Ore by Thiobacillus Ferrooxidans.  

ERIC Educational Resources Information Center

A quantitative laboratory exercise based upon the procedures copper manufacturers employ to increase copper production is described. The role of chemoautotrophic microorganisms in biogeologic process is emphasized. Safety considerations when working with bacteria are included. (KR)

Lennox, John; Biaha, Thomas

1991-01-01

286

Thermotransport in liquid aluminum-copper alloys  

NASA Technical Reports Server (NTRS)

A thermotransport study was made on a series of liquid aluminum-copper alloys which contained from trace amounts to 33 weight percent copper. The samples in the form of narrow capillaries were held in known temperature gradient of thermotransport apparatus until the stationary state was reached. The samples were analyzed for the concentration of copper along the length. Copper was observed to migrate to the colder regions in all the samples. The heat of transport, Q*, was determined for each composition from a plot of concentration of copper versus reciprocal absolute temperature. The value of Q* is the highest at trace amounts of copper (4850 cal/gm-atom), but decreases with increasing concentration of copper and levels off to 2550 cal/gm-atom at about 25 weight percent copper. The results are explained on the basis of electron-solute interaction and a gas model of diffusion.

Bhat, B. N.

1973-01-01

287

High-temperature oxidation of copper  

NASA Astrophysics Data System (ADS)

Data on the kinetics and thermodynamics of high-temperature oxidation of copper are generalized. The attention is focused on the catastrophic oxidation of copper contacting some low-melting oxides. The results of experimental and theoretical studies of the last 10 years concerning the catastrophic oxidation of copper are analyzed. The theory of catastrophic oxidation of copper under a thin layer of low-melting oxide is considered. The bibliography includes 135 references.

Belousov, Valerii V.; Klimashin, A. A.

2013-03-01

288

Contribution of Copper Ion Resistance to Survival of Escherichia coli on Metallic Copper Surfaces?  

PubMed Central

Bacterial contamination of touch surfaces poses a serious threat for public health. The use of bactericidal surface materials, such as copper and its alloys, might constitute a way to aid the use of antibiotics and disinfectants, thus minimizing the risk of emergence and spread of multiresistant germs. The survival of Escherichia coli on metallic copper surfaces has been studied previously; however, the mechanisms underlying bacterial inactivation on copper surfaces have not been elucidated. Data presented in this study suggest that bacteria are killed rapidly on dry copper surfaces. Several factors, such as copper ion toxicity, copper chelators, cold, osmotic stress, and reactive oxygen species, but not anaerobiosis, influenced killing rates. Strains deleted in copper detoxification systems were slightly more sensitive than was the wild type. Preadaptation to copper enhanced survival rates upon copper surface exposure. This study constitutes a first step toward understanding the reasons for metallic copper surface-mediated killing of bacteria.

Santo, Christophe Espirito; Taudte, Nadine; Nies, Dietrich H.; Grass, Gregor

2008-01-01

289

Copper Electrodeposition: Principles and Recent Progress  

Microsoft Academic Search

The capability of copper electroplating to produce void free filling of sub-micron high aspect ratio features has made it the process of choice for copper interconnect formation. Several aspects of copper electrodeposition including the basic electrochemistry and electrochemical kinetics, mass transport phenomena, potential gradients in solution, electrolyte composition, and the influence of various organic additives have been studied for over

Jonathan Reid

2001-01-01

290

Composite copper\\/stainless steel coated powders  

Microsoft Academic Search

The present research work concerns the development of new composites based on austenitic stainless steel (SS) or copper (Cu) microsized powders coated with thin nanostructured layers of copper or stainless steels, respectively. A home-manufactured magnetron sputtering system equipped with a powder vibration device was used to coat the powders. A detailed analysis of the coated copper or stainless steel powders

Mariana Matos; José M. Castanho; Maria T. Vieira

2009-01-01

291

21 CFR 524.463 - Copper naphthenate.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Copper naphthenate. 524.463 Section...FORM NEW ANIMAL DRUGS § 524.463 Copper naphthenate. (a) Amount . The drug is a 37.5 percent solution of copper naphthenate. (b) Sponsors....

2013-04-01

292

Modeling copper partitioning in surface waters  

Microsoft Academic Search

Suspended particulate matter from the surface waters of the Susquehanna, Christina and Brandywine Rivers was collected by tangential flow filtration to study copper partitioning. Copper adsorption increased with an increase of suspended particles and decreased with low pH values or with an increase of dissolved organic matter. Effects of particulate organic matter on copper distribution between suspended particulate and solution

Bo Shi; Herbert E. Allen; Marco T. Grassi; Huizhong Ma

1998-01-01

293

Cobalt distribution during copper matte smelting  

Microsoft Academic Search

Many smelter operators subscribe to the ``precautionary principle'' and wish to understand the behavior of the metals and impurities during smelting, especially how they distribute between product and waste phases and whether these phases lead to environmental, health, or safety issues. In copper smelting, copper and other elements are partitioned between copper matte, iron silicate slag, and possibly the waste

T. S. Kho; D. R. Swinbourne; T. Lehner

2006-01-01

294

Electrochromism in copper oxide thin films.  

National Technical Information Service (NTIS)

Transparent thin films of copper(I) oxide prepared on conductive SnO2:F glass substrates by anodic oxidation of sputtered copper films or by direct electrodeposition of Cu2O transformed reversibly to opaque metallic copper films when reduced in alkaline e...

T. J. Richardson J. L. Slack M. D. Rubin

2000-01-01

295

Plasma copper concentrations in pathological pregnancies  

Microsoft Academic Search

Copper is an essential element required for the formation of many enzymes with important roles in the human body. During pregnancy, the maternal serum copper concentration is increased due to the higher levels of ceruloplasmin that are the result of elevated oestrogen levels. The aim of this work was to investigate maternal plasma copper concentrations in relation to various pathological

Ana Alebic-Juretic; Aleksandra Frkovic

2005-01-01

296

21 CFR 184.1260 - Copper gluconate.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Copper gluconate. 184.1260 Section 184.1260 Food and...Substances Affirmed as GRAS § 184.1260 Copper gluconate. (a) Copper gluconate (cupric gluconate (CH2 OH(CHOH)4...

2009-04-01

297

THE EVOLUTION OF SYNTHETICALLY PRECIPITATED COPPER SOLIDS  

EPA Science Inventory

The objective of this study was to explore the effect of water quality, particularly chloride and sulfate, on copper mineral formation. Copper-sulfate and chloride compounds are often found on the surface of copper pipes in drinking water distribution systems. When attempting to ...

298

Copper coating specification for the RHIC arcs  

SciTech Connect

Copper coating specifications for the RHIC arcs are given. Various upgrade scenarios are considered and calculations of resistive wall losses in the arcs are used to constrain the necessary quality and surface thickness of a copper coating. We find that 10 {mu}m of high purity copper will suffice.

Blaskiewicz, M.

2010-12-01

299

21 CFR 73.1647 - Copper powder.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Copper powder. 73.1647 Section 73.1647 Food...CERTIFICATION Drugs § 73.1647 Copper powder. (a) Identity. (1) The color additive copper powder is a very fine free-flowing...

2013-04-01

300

Molybdenum-copper and tungsten-copper alloys and method of making  

DOEpatents

Molybdenum-copper and tungsten-copper alloys are prepared by a consumable electrode method in which the electrode consists of a copper matrix with embedded strips of refractory molybdenum or tungsten. The electrode is progressively melted at its lower end with a superatmospheric inert gas pressure maintained around the liquefying electrode. The inert gas pressure is sufficiently above the vapor pressure of copper at the liquidus temperature of the alloy being formed to suppress boiling of liquid copper. 6 figs.

Schmidt, F.A.; Verhoeven, J.D.; Gibson, E.D.

1989-05-23

301

Molybdenum-copper and tungsten-copper alloys and method of making  

DOEpatents

Molybdenum-copper and tungsten-copper alloys are prepared by a consumable electrode method in which the electrode consists of a copper matrix with embedded strips of refractory molybdenum or tungsten. The electrode is progressively melted at its lower end with a superatmospheric inert gas pressure maintained around the liquifying electrode. The inert gas pressure is sufficiently above the vapor pressure of copper at the liquidus temperature of the alloy being formed to suppress boiling of liquid copper.

Schmidt, Frederick A. (Ames, IA); Verhoeven, John D. (Ames, IA); Gibson, Edwin D. (Ames, IA)

1989-05-23

302

Influence of carboxylic acids on fixation of copper in wood impregnated with copper amine based preservatives  

Microsoft Academic Search

The importance of copper\\/amine based preservatives is increasing. Leaching of copper from wood preserved with these solutions\\u000a is still higher than leaching from wood impregnated with copper chromium ones. In order to decrease leaching, different carboxylic\\u000a acids (octanoic, 2-ethylhexanoic, decanoic) were added to copper\\/amine\\/boron aqueous solutions. An experiment of leaching\\u000a of copper from Norway spruce was performed according to the

M. Humar; P. Kalan; M. Šentjurc; F. Pohleven

2005-01-01

303

Copper vs. Copper at the Relativistic Heavy Ion Collider (2005)  

SciTech Connect

To investigate a new form of matter not seen since the Big Bang, scientists are using a new experimental probe: collisions between two beams of copper ions. The use of intermediate size nuclei is expected to result in intermediate energy density - not as

Brookhaven Lab - Fulvia Pilat

2009-06-09

304

Joining of alumina via copper/niobium/copper interlayers  

SciTech Connect

Alumina has been joined at 1150 degrees C and 1400 degrees C using multilayer copper/niobium/copper interlayers. Four-point bend strengths are sensitive to processing temperature, bonding pressure, and furnace environment (ambient oxygen partial pressure). Under optimum conditions, joints with reproducibly high room temperature strengths (approximately equal 240 plus/minus 20 MPa) can be produced; most failures occur within the ceramic. Joints made with sapphire show that during bonding an initially continuous copper film undergoes a morphological instability, resulting in the formation of isolated copper-rich droplets/particles at the sapphire/interlayer interface, and extensive regions of direct bonding between sapphire and niobium. For optimized alumina bonds, bend tests at 800 degrees C-1100 degrees C indicate significant strength is retained; even at the highest test temperature, ceramic failure is observed. Post-bonding anneals at 1000 degrees C in vacuum or in gettered argon were used to assess joint stability and to probe the effect of ambient oxygen partial pressure on joint characteristics. Annealing in vacuum for up to 200 h causes no significant decrease in room temperature bend strength or change in fracture path. With increasing anneal time in a lower oxygen partial pressure environment, the fracture strength decreases only slightly, but the fracture path shifts from the ceramic to the interface.

Marks, Robert A.; Chapman, Daniel R.; Danielson, David T.; Glaeser, Andreas M.

2000-03-15

305

Copper vs. Copper at the Relativistic Heavy Ion Collider (2005)  

ScienceCinema

To investigate a new form of matter not seen since the Big Bang, scientists are using a new experimental probe: collisions between two beams of copper ions. The use of intermediate size nuclei is expected to result in intermediate energy density - not as

Brookhaven Lab - Fulvia Pilat

2010-01-08

306

BotEC: Percentage of Copper in Ore  

NSDL National Science Digital Library

Question Suppose that you are building a new house. It will take about 90 kg (198 pounds) of copper to do the electrical wiring. In order to get the copper in the first place, someone needs to mine solid rock that contains copper, extract the copper minerals, throw away the waste rock, and smelt the copper minerals to produce copper metal. Rocks mined for copper typically contain only very small percentages of copperâabout 0.7% in the case of most of the big porphyry copper deposits of the world. How much rock would someone have to mine in order to extract enough copper to wire your new house?

Tewksbury, Barb

307

Zinc sulfide and zinc selenide immersion gratings for astronomical high-resolution spectroscopy: evaluation of internal attenuation of bulk materials in the short near-infrared region  

NASA Astrophysics Data System (ADS)

We measure the internal attenuation of bulk crystals of chemical vapor deposition zinc selenide (CVD-ZnS), chemical vapor deposition zinc sulfide (CVD-ZnSe), Si, and GaAs in the short near-infrared (sNIR) region to evaluate the possibility of astronomical immersion gratings with those high refractive index materials. We confirm that multispectral grade CVD-ZnS and CVD-ZnSe are best suited for the immersion gratings, with the smallest internal attenuation of ?att=0.01 to 0.03 cm-1 among the major candidates. The measured attenuation is roughly in proportion to ?-2, suggesting it is dominated by bulk scattering due to the polycrystalline grains rather than by absorption. The total transmittance in the immersion grating is estimated to be at least >80%, even for the spectral resolution of R=300,000. Two potential problems, the scattered light by the bulk material and the degradation of the spectral resolution due to the gradient illumination in the diffracted beam, are investigated and found to be negligible for usual astronomical applications. Since the remaining problem, the difficulty of cutting grooves on CVD-ZnS and CVD-ZnSe, has recently been overcome by the nanoprecision fly-cutting technique, ZnS and ZnSe immersion gratings for astronomy can be technically realized.

Ikeda, Yuji; Kobayashi, Naoto; Kondo, Sohei; Yasui, Chikako; Kuzmenko, Paul J.; Tokoro, Hitoshi; Terada, Hiroshi

2009-08-01

308

Electronic characterization of defects in narrow gap semiconductors: Comparison of electronic energy levels and formation energies in mercury cadmium telluride, mercury zinc telluride, and mercury zinc selenide  

NASA Technical Reports Server (NTRS)

The project has evolved to that of using Green's functions to predict properties of deep defects in narrow gap materials. Deep defects are now defined as originating from short range potentials and are often located near the middle of the energy gap. They are important because they affect the lifetime of charge carriers and hence the switching time of transistors. We are now moving into the arena of predicting formation energies of deep defects. This will also allow us to make predictions about the relative concentrations of the defects that could be expected at a given temperature. The narrow gap materials mercury cadmium telluride (MCT), mercury zinc telluride (MZT), and mercury zinc selenide (MZS) are of interest to NASA because they have commercial value for infrared detecting materials, and because there is a good possibility that they can be grown better in a microgravity environment. The uniform growth of these crystals on earth is difficult because of convection (caused by solute depletion just ahead of the growing interface, and also due to thermal gradients). In general it is very difficult to grow crystals with both radial and axial homogeneity.

Patterson, James D.; Li, Wei-Gang

1995-01-01

309

Na3.88Mo15Se19: a novel ternary reduced molybdenum selenide containing Mo6 and Mo9 clusters.  

PubMed

The structure of tetrasodium penta-deca-molybdenum nona-deca-selenide, Na3.88Mo15Se19, is isotypic with the In3+x Mo15Se19 compounds [Grüttner et al. (1979 ?). Acta Cryst. B35, 285-292]. It is characterized by two cluster units, Mo6Se (i) 8Se (a) 6 and Mo9Se (i) 11Se (a) 6 (where i represents inner and a apical atoms), that are present in a 1:1 ratio. The cluster units are centered at Wyckoff positions 2b and 2c and have point-group symmetry -3 and -6, respectively. The clusters are inter-connected through additional Mo-Se bonds. In the title compound, the Na(+) cations replace the trivalent as well as the monovalent indium atoms present in In3.9Mo15Se19. One Mo, one Se and one Na atom are situated on mirror planes, and two other Se atoms and one Na atom [occupancy 0.628?(14)] are situated on threefold rotation axes. The crystal studied was twinned by merohedry with refined components of 0.4216?(12) and 0.5784?(12). PMID:24098158

Salloum, Diala; Gougeon, Patrick; Gall, Philippe

2013-01-01

310

Hydrothermal synthesis of [C 6H 16N 2][In 2Se 3(Se 2)]: A new one-dimensional indium selenide  

NASA Astrophysics Data System (ADS)

A new organically templated indium selenide, [C 6H 16N 2][In 2Se 3(Se 2)], has been prepared hydrothermally from the reaction of indium, selenium and trans-1,4-diaminocyclohexane in water at 170 °C. This material was characterised by single-crystal and powder X-ray diffraction, thermogravimetric analysis, UV-vis diffuse reflectance spectroscopy, FT-IR and elemental analysis. The compound crystallises in the monoclinic space group C2/ c ( a=12.0221(16) Å, b=11.2498(15) Å, c=12.8470(17) Å, ?=110.514(6)°). The crystal structure of [C 6H 16N 2][In 2Se 3(Se 2)] contains anionic chains of stoichiometry [In 2Se 3(Se 2)] 2-, which are aligned parallel to the [1 0 1] direction, and separated by diprotonated trans-1,4-diaminocyclohexane cations. The [In 2Se 3(Se 2)] 2- chains, which consist of alternating four-membered [In 2Se 2] and five-membered [In 2Se 3] rings, contain perselenide (Se 2) 2- units. UV-vis diffuse reflectance spectroscopy indicates that [C 6H 16N 2][In 2Se 3(Se 2)] has a band gap of 2.23(1) eV.

Ewing, Sarah J.; Powell, Anthony V.; Vaqueiro, Paz

2011-07-01

311

Thermo-optical characterization of cadmium selenide/zinc sulfide (CdSe/ZnS) quantum dots embedded in biocompatible materials.  

PubMed

Cadmium selenide/zinc sulfide (CdSe/ZnS) core-shell quantum dots (QDs) embedded in biocompatible materials were thermally and optically characterized with a thermal lens (TL) technique. Transient TL measurements were performed with a mode-mismatched, dual-beam (excitation and probe) configuration. A thermo-optical study of the CdSe/ZnS QDs was performed for different core diameters (3.5, 4.0, 5.2, and 6.6 nm) in aqueous solution and synthetic saliva, and three different core diameters (2.4, 2.9, and 4.1 nm) embedded in restorative dental resin (0.025% by mass). The thermal diffusivity results are characteristic of the biocompatible matrices. The radiative quantum efficiencies for aqueous solution and biofluid materials are dependent on the core size of the CdSe/ZnS core-shell QDs. The results obtained from the fluorescence spectral measurements for the biocompatible materials support the TL results. PMID:24067629

Pilla, Viviane; Alves, Leandro P; Iwazaki, Adalberto N; Andrade, Acácio A; Antunes, Andrea; Munin, Egberto

2013-09-01

312

Synthesis and characterization of Cadmium selenide nanoparticles loaded on activated carbon and its efficient application for removal of Muroxide from aqueous solution  

NASA Astrophysics Data System (ADS)

In the first, Cadmium selenide Nanoparticle loaded on activated carbon (CdSe-NP-AC) has been synthesized and characterized by different techniques including XRD and SEM. Then, this new adsorbent successfully has been applied for the removal of muroxide (MO) from aqueous solution in batch studies, while the effect of various experimental parameters like initial pH (pH 0), contact time, amount of (CdSe-NP-AC) and initial MO concentration ( C0) on its removal percentage was examined by one at a time optimization method. It was found following optimization of variable, the adsorption of MO onto (CdSe-NP-AC) followed pseudo-second-order kinetics and show Tempkin and Langmuir models for interpretation of experimental data. It was observed that by increasing the temperature the removal percentage was improved and the positive change in entropy (? S°) and heat of adsorption (? H°) show the endothermic nature of process, while the high negative value in Gibbs free energy change (? G°) indicates the feasible nature of adsorption process.

Ghaedi, M.; Amirabad, S. Zamani; Marahel, F.; Nasiri Kokhdan, S.; Sahraei, R.; Nosrati, M.; Daneshfar, A.

2011-12-01

313

Metabolic crossroads of iron and copper  

PubMed Central

Interactions between the essential dietary metals, iron and copper, have been known for many years. This review highlights recent advances in iron-copper interactions with a focus on tissues and cell types important for regulating whole-body iron and copper homeostasis. Cells that mediate dietary assimilation (enterocytes) and storage and distribution (hepatocytes) of iron and copper are considered, along with the principal users (erythroid cells) and recyclers of red cell iron (reticuloendothelial macrophages). Interactions between iron and copper in the brain are also discussed. Many unanswered questions regarding the role of these metals and their interactions in health and disease emerge from this synopsis, highlighting extensive future research opportunities.

Collins, James F; Prohaska, Joseph R; Knutson, Mitchell D

2013-01-01

314

Advantages and challenges of increased antimicrobial copper use and copper mining.  

PubMed

Copper is a highly utilized metal for electrical, automotive, household objects, and more recently as an effective antimicrobial surface. Copper-containing solutions applied to fruits and vegetables can prevent bacterial and fungal infections. Bacteria, such as Salmonellae and Cronobacter sakazakii, often found in food contamination, are rapidly killed on contact with copper alloys. The antimicrobial effectiveness of copper alloys in the healthcare environment against bacteria causing hospital-acquired infections such as methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli O157:H7, and Clostridium difficile has been described recently. The use of copper and copper-containing materials will continue to expand and may lead to an increase in copper mining and production. However, the copper mining and manufacturing industry and the consumer do not necessarily enjoy a favorable relationship. Open pit mining, copper mine tailings, leaching products, and deposits of toxic metals in the environment often raises concerns and sometimes public outrage. In addition, consumers may fear that copper alloys utilized as antimicrobial surfaces in food production will lead to copper toxicity in humans. Therefore, there is a need to mitigate some of the negative effects of increased copper use and copper mining. More thermo-tolerant, copper ion-resistant microorganisms could improve copper leaching and lessen copper groundwater contamination. Copper ion-resistant bacteria associated with plants might be useful in biostabilization and phytoremediation of copper-contaminated environments. In this review, recent progress in microbiological and biotechnological aspects of microorganisms in contact with copper will be presented and discussed, exploring their role in the improvement for the industries involved as well as providing better environmental outcomes. PMID:21656137

Elguindi, Jutta; Hao, Xiuli; Lin, Yanbing; Alwathnani, Hend A; Wei, Gehong; Rensing, Christopher

2011-07-01

315

Micro milling of pure copper  

Microsoft Academic Search

Unpredictable tool life and premature tool failure are the major concerns in micro machining using micro grain carbide cutters. In this study, the failure mechanism and factors which affect the micro end mill were studied during machining of pure copper workpiece. The machining operation were performed at various cutting speeds, depth of cuts, and feed rates to identify the failure

M Rahman; A Senthil Kumar; J. R. S Prakash

2001-01-01

316

CopperCore Service Integration  

ERIC Educational Resources Information Center

In an e-learning environment there is a need to integrate various e-learning services like assessment services, collaboration services, learning design services and communication services. In this article we present the design and implementation of a generic integrative service framework, called CopperCore Service Integration (CCSI). We will…

Vogten, Hubert; Martens, Harrie; Nadolski, Rob; Tattersall, Colin; van Rosmalen, Peter; Koper, Rob

2007-01-01

317

Building a Copper Pipe "Xylophone."  

ERIC Educational Resources Information Center

Explains how to use the equation for frequency of vibration of a transversely oscillating bar or pipe with both ends free to vibrate to build a simple and inexpensive xylophone from a 3-meter section of copper pipe. The instrument produces a full major scale and can be used to investigate various musical intervals. (Author/NB)

Lapp, David R.

2003-01-01

318

Michigan's Copper Country in Photographs  

NSDL National Science Digital Library

Copper production has gone on around Michigan's Keweenaw Peninsula for over 3,000 years. Native Americans first engaged in the practice these many millennia ago, and by the 1840s, there were mineral rushes going on in the area. Many thousands of people came in search of copper, and by 1985, over 14 billion pounds of copper were produced from the region. This remarkable digital collection crafted by Michigan Technological University brings together many historical photographs that document the district. All told, there are over 3,500 items here, and visitors can search the holdings by keyword or more detailed parameters. Visitors also have the option of creating their own personal web album with items of interest to them. The Subject Browse tab is a good way to delve into the collection, as visitors can look over anything from Accidents to Woody Plants. This collection illuminates the region and the ways in which the copper industry transformed this rural and bucolic environment.

2008-06-19

319

Copper adsorption in diatom cultures  

Microsoft Academic Search

The organic ligands naturally present in seawater, on the cell surface groups, and those released by the marine phytoplankton species, Thalassiosira weissflogii and Phaeodactylum tricornutum , and their physico-chemical interaction . with copper ions were studied using differential pulse anodic stripping voltammetry DPASV as a function of pH, temperature, salinity and biomass. The acid-base properties were characterized from titration curves

Melchor Gonzalez-Davila; J. Magdalena Santana-Casiano; Luis M. Laglera ´ ´

320

Solar cogeneration for copper smelting  

Microsoft Academic Search

Work is reported on designing a system for solar repowering of a cogenerating flash smelting furnace that produces copper and sulfuric acid. Smelter energy requirements are listed and the proposed project is described. Several modifications to existing equipment and additional investment in the plant are listed that are necessary as a result of the solar power system improvement. Expected enhancements

P. Curto; A. Gillespie

1981-01-01

321

Subclinical copper accumulation in llamas.  

PubMed Central

A 9-year-old, intact male llama with mild ataxia and generalized malaise of 1 month's duration was euthanized following clinical evaluation. Excessive liver copper concentrations were found in the llama and also in clinically normal herdmates. This case documents multiple animals with increased hepatic stores from standard diets and mineral supplements.

Weaver, D M; Tyler, J W; Marion, R S; Casteel, S W; Loiacono, C M; Turk, J R

1999-01-01

322

Copper-Doped Germanium Detectors.  

National Technical Information Service (NTIS)

Background limited operation of copper-doped germanium detectors has been obtained for a background as low as 10 to the minus 11th power watts (5 x 10 to the 8th power photons/second) in the 8-12 microns region. The temperature dependence of the observed ...

T. M. Quist

1968-01-01

323

Improved copper septum magnet design  

SciTech Connect

A copper septum magnet of improved design has been developed to replace the existing F5 septum deflector in the slow-extraction channel at the Brookhaven National Laboratory AGS. The new magnet has several novel design features such as a solid rather than laminated core, a ball bearing suspended septum and a radiation resistant quick disconnect system.

Rodger, E S; Weisberg, H L

1981-01-01

324

COPPER CORROSION AND SOLUBILITY RESEARCH  

EPA Science Inventory

This poster provides a very cursory summary of TTEB in-house copper research experimental systems, and extramural research projects. The field studies summarized are the Indian Hill (OH) study of the use of orthophosphate for reducing cuprosolvency in a high alkalinity water, an...

325

Brazing Stainless Steel to Copper  

Microsoft Academic Search

A requiremcnt often encountered in electron tube developmental work is ; the joining of copper to stainless steel. The usual methods of pcrforming such ; brazes require that a protective nickel coating first be applied to the stain ; equent brazing operation be carried out in dry hydrogen. An ; alternative method not requiring hydrogen, prior to nickel plating, or

Morris Liebson

1959-01-01

326

XIAP: CELL DEATH REGULATION MEETS COPPER HOMEOSTASIS  

PubMed Central

SUMMARY X-linked inhibitor of apoptosis (XIAP), traditionally known as an anti-apoptotic protein, has recently been shown to be involved in copper homeostasis. XIAP promotes the ubiquitination and degradation of COMMD1, a protein that promotes the efflux of copper from the cell. Through its effects on COMMD1, XIAP can regulate copper export from the cell and potentially represents an additional intracellular sensor for copper levels. XIAP binds copper directly and undergoes a substantial conformational change in the copper bound state. This in turn destabilizes XIAP, resulting in lowered steady-state levels of the protein. Furthermore, copper-bound XIAP is unable to inhibit caspases and cells that express this form of the protein exhibit increased rates of cell death in response to apoptotic stimuli. These events take place in the setting of excess intracellular copper accumulation as seen in copper toxicosis disorders such as Wilson's disease and establish a new relationship between copper levels and the regulation of cell death via XIAP. These findings raise important questions about the role of XIAP in the development of copper toxicosis disorders and may point to XIAP as a potential therapeutic target in these disease states.

Mufti, Arjmand R.; Burstein, Ezra; Duckett, Colin S.

2007-01-01

327

The copper chaperone for superoxide dismutase.  

PubMed

Copper is distributed to distinct localizations in the cell through diverse pathways. We demonstrate here that the delivery of copper to copper/zinc superoxide dismutase (SOD1) is mediated through a soluble factor identified as Saccharomyces cerevisiae LYS7 and human CCS (copper chaperone for SOD). This factor is specific for SOD1 and does not deliver copper to proteins in the mitochondria, nucleus, or secretory pathway. Yeast cells containing a lys7Delta null mutation have normal levels of SOD1 protein, but fail to incorporate copper into SOD1, which is therefore devoid of superoxide scavenging activity. LYS7 and CCS specifically restore the biosynthesis of holoSOD1 in vivo. Elucidation of the CCS copper delivery pathway may permit development of novel therapeutic approaches to human diseases that involve SOD1, including amyotrophic lateral sclerosis. PMID:9295278

Culotta, V C; Klomp, L W; Strain, J; Casareno, R L; Krems, B; Gitlin, J D

1997-09-19

328

Process Of Bonding Copper And Tungsten  

DOEpatents

Process for bonding a copper substrate to a tungsten substrate by providing a thin metallic adhesion promoting film bonded to a tungsten substrate and a functionally graded material (FGM) interlayer bonding the thin metallic adhesion promoting film to the copper substrate. The FGM interlayer is formed by thermal plasma spraying mixtures of copper powder and tungsten powder in a varied blending ratio such that the blending ratio of the copper powder and the tungsten powder that is fed to a plasma torch is intermittently adjusted to provide progressively higher copper content/tungsten content, by volume, ratio values in the interlayer in a lineal direction extending from the tungsten substrate towards the copper substrate. The resulting copper to tungsten joint well accommodates the difference in the coefficient of thermal expansion of the materials.

Slattery, Kevin T. (St. Charles, MO); Driemeyer, Daniel E. (Manchester, MO)

1999-11-23

329

Controlling Copper Electrochemical Deposition (ECD)  

NASA Astrophysics Data System (ADS)

The implementation of copper processing in semiconductor manufacturing has resulted in major process development and manufacturing challenges. A fundamental understanding of the copper plating processes used in manufacturing has been limited by the lack of in-line methods for direct measurement and control of process chemistry. Plating bath chemistry adjustments and change-out frequencies are currently determined using a combination of indirect electrochemical monitoring techniques, off-line analyses of wafer metrology and analytical lab measurements. There have been a number of industry reports of major process startup delays, yield management problems and reliability issues as a result of these difficulties. A new in-process mass spectrometry (IPMS) approach enables automated, real-time measurement of both the inorganic components and organic additives in the copper electroplating chemistry as they change during production. The tool is not only capable of real time direct quantification of the copper, chloride, pH, and organic additives in the plating bath, but can also monitor additive breakdown byproducts as they occur during the production process. These breakdown products, as well as changes in the original bath constituent composition can be expected to have a major impact on process performance. We are now in the process of measuring longer term plating bath stability and chemistry changes in prototype applications in semiconductor fab manufacturing environments. The first results demonstrate improved process understanding and the potential for greatly improved process control. We will discuss the technical challenges that were successfully addressed in developing the IPMS capability for application to the copper plating process and the initial process data subsequently obtained.

West, Michael; McDonald, Robert; Anderson, Marc; Kingston, Skip; Mui, Rudy

2003-09-01

330

Radiation resistance of copper alloys at high exposure levels  

SciTech Connect

Copper alloys are currently being considered for high heat flux applications in fusion power devices. A review is presented of the results of two separate series of experiments on the radiation response of copper and copper alloys. One of these involved pure copper and boron-doped copper in the ORR mixed spectrum reactor. The other series included pure copper and a wide array of copper alloys irradiated in the FFTF fast reactor 16 refs., 13 figs.

Garner, F.A. (Pacific Northwest Lab., Richland, WA (USA)); Zinkle, S.J. (Oak Ridge National Lab., TN (USA))

1990-08-01

331

Copper uptake and retention in liver parenchymal cells isolated from nutritionally copper-deficient rats  

SciTech Connect

Copper uptake and retention were studied in primary cultures of liver parenchymal cells isolated from copper-deficient rats. Male Sprague-Dawley rats were fed a copper-deficient diet (less than 1 mg Cu/kg) for 10 wk. Copper-deficient rats were characterized by low copper concentrations in plasma and liver, anemia, low plasma ceruloplasmin oxidase activity and increased 64Cu whole-body retention. Freshly isolated liver parenchymal cells from copper-deficient rats showed a higher 64Cu influx, which was associated with a higher apparent Vmax of 45 {plus minus} 4 pmol Cu.mg protein-1.min-1 as compared with 30 {plus minus} 3 pmol Cu.mg protein-1.min-1 for cells isolated from copper-sufficient rats. No significant difference in the apparent Km (approximately 30 mumol/L) was observed. Relative 64Cu efflux from cells from copper-deficient rats was significantly smaller than the efflux from cells from copper-sufficient rats after prelabeling as determined by 2-h efflux experiments. Analysis of the medium after efflux from cells from copper-deficient rats showed elevated protein-associated 64Cu, suggesting a higher incorporation of radioactive copper during metalloprotein synthesis. Effects of copper deficiency persist in primary cultures of parenchymal cells derived from copper-deficient rats, and short-term cultures of these cells offer a prospect for the study of cell biological aspects of the metabolic adaptation of the liver to copper deficiency.

Van den Berg, G.J.; de Goeij, J.J.; Bock, I.; Gijbels, M.J.; Brouwer, A.; Lei, K.Y.; Hendriks, H.F. (Interfaculty Reactor Institute, Delft University of Technology (Netherlands))

1991-08-01

332

A Plasmodium falciparum copper-binding membrane protein with copper transport motifs  

PubMed Central

Background Copper is an essential catalytic co-factor for metabolically important cellular enzymes, such as cytochrome-c oxidase. Eukaryotic cells acquire copper through a copper transport protein and distribute intracellular copper using molecular chaperones. The copper chelator, neocuproine, inhibits Plasmodium falciparum ring-to-trophozoite transition in vitro, indicating a copper requirement for malaria parasite development. How the malaria parasite acquires or secretes copper still remains to be fully elucidated. Methods PlasmoDB was searched for sequences corresponding to candidate P. falciparum copper-requiring proteins. The amino terminal domain of a putative P. falciparum copper transport protein was cloned and expressed as a maltose binding fusion protein. The copper binding ability of this protein was examined. Copper transport protein-specific anti-peptide antibodies were generated in chickens and used to establish native protein localization in P. falciparum parasites by immunofluorescence microscopy. Results Six P. falciparum copper-requiring protein orthologs and a candidate P. falciparum copper transport protein (PF14_0369), containing characteristic copper transport protein features, were identified in PlasmoDB. The recombinant amino terminal domain of the transport protein bound reduced copper in vitro and within Escherichia coli cells during recombinant expression. Immunolocalization studies tracked the copper binding protein translocating from the erythrocyte plasma membrane in early ring stage to a parasite membrane as the parasites developed to schizonts. The protein appears to be a PEXEL-negative membrane protein. Conclusion Plasmodium falciparum parasites express a native protein with copper transporter characteristics that binds copper in vitro. Localization of the protein to the erythrocyte and parasite plasma membranes could provide a mechanism for the delivery of novel anti-malarial compounds.

2012-01-01

333

Uptake and internalisation of copper by three marine microalgae: comparison of copper-sensitive and copper-tolerant species.  

PubMed

Although it has been well established that different species of marine algae have different sensitivities to metals, our understanding of the physiological and biochemical basis for these differences is limited. This study investigated copper adsorption and internalisation in three algal species with differing sensitivities to copper. The diatom Phaeodactylum tricornutum was particularly sensitive to copper, with a 72-h IC50 (concentration of copper to inhibit growth rate by 50%) of 8.0 microg Cu L(-1), compared to the green algae Tetraselmis sp. (72-h IC50 47 microg Cu L(-1)) and Dunaliella tertiolecta (72-h IC50 530 microg Cu L(-1)). At these IC50 concentrations, Tetraselmis sp. had much higher intracellular copper (1.97+/-0.01 x 10(-13)g Cu cell(-1)) than P. tricornutum (0.23+/-0.19 x 10(-13)g Cu cell(-1)) and D. tertiolecta (0.59+/-0.05 x 10(-13)g Cu cell(-1)), suggesting that Tetraselmis sp. effectively detoxifies copper within the cell. By contrast, at the same external copper concentration (50 microg L(-1)), D. tertiolecta appears to better exclude copper than Tetraselmis sp. by having a slower copper internalisation rate and lower internal copper concentrations at equivalent extracellular concentrations. The results suggest that the use of internal copper concentrations and net uptake rates alone cannot explain differences in species-sensitivity for different algal species. Model prediction of copper toxicity to marine biota and understanding fundamental differences in species-sensitivity will require, not just an understanding of water quality parameters and copper-cell binding, but also further knowledge of cellular detoxification mechanisms. PMID:18639348

Levy, Jacqueline L; Angel, Brad M; Stauber, Jennifer L; Poon, Wing L; Simpson, Stuart L; Cheng, Shuk Han; Jolley, Dianne F

2008-08-29

334

Inner-layer copper reliability of electroless copper processes  

Microsoft Academic Search

Purpose – The purpose of this paper is to present an overview of the alternative testing approaches that may be used to assess interconnect quality and their application to laminate material and plated-through-hole (PTH) process control. Design\\/methodology\\/approach – The paper introduces the importance of inner-layer copper reliability and how to evaluate it. It reviews and discusses the effects of all

Crystal P. L. Li; Paul Ciccolo; Dennis K. W. Yee

2010-01-01

335

Metallic Copper as an Antimicrobial Surface?  

PubMed Central

Bacteria, yeasts, and viruses are rapidly killed on metallic copper surfaces, and the term “contact killing” has been coined for this process. While the phenomenon was already known in ancient times, it is currently receiving renewed attention. This is due to the potential use of copper as an antibacterial material in health care settings. Contact killing was observed to take place at a rate of at least 7 to 8 logs per hour, and no live microorganisms were generally recovered from copper surfaces after prolonged incubation. The antimicrobial activity of copper and copper alloys is now well established, and copper has recently been registered at the U.S. Environmental Protection Agency as the first solid antimicrobial material. In several clinical studies, copper has been evaluated for use on touch surfaces, such as door handles, bathroom fixtures, or bed rails, in attempts to curb nosocomial infections. In connection to these new applications of copper, it is important to understand the mechanism of contact killing since it may bear on central issues, such as the possibility of the emergence and spread of resistant organisms, cleaning procedures, and questions of material and object engineering. Recent work has shed light on mechanistic aspects of contact killing. These findings will be reviewed here and juxtaposed with the toxicity mechanisms of ionic copper. The merit of copper as a hygienic material in hospitals and related settings will also be discussed.

Grass, Gregor; Rensing, Christopher; Solioz, Marc

2011-01-01

336

Mechanisms of copper incorporation into human ceruloplasmin.  

PubMed

Ceruloplasmin is a multicopper oxidase essential for normal iron homeostasis. To elucidate the mechanisms of copper incorporation into this protein, holoceruloplasmin biosynthesis was examined by immunoblot analysis and (64)Cu metabolic labeling of Chinese hamster ovary cells transfected with cDNAs encoding wild-type or mutant ceruloplasmin. This analysis reveals that the incorporation of copper into newly synthesized apoceruloplasmin in vivo results in a detectable conformational change in the protein. Strikingly, despite the unique functional role of each copper site within ceruloplasmin, metabolic studies indicate that achieving this final conformation-driven state requires the occupation of all six copper-binding sites with no apparent hierarchy for copper incorporation at any given site. Consistent with these findings a missense mutation (G631R), resulting in aceruloplasminemia and predicted to alter the interactions at a single type I copper-binding site, results in the synthesis and secretion only of apoceruloplasmin. Analysis of copper incorporation into apoceruloplasmin in vitro reveals that this process is cooperative and that the failure of copper incorporation into copper-binding site mutants observed in vivo is intrinsic to the mutant proteins. These findings reveal a precise and sensitive mechanism for the formation of holoceruloplasmin under the limiting conditions of copper availability within the cell that may be generally applicable to the biosynthesis of cuproproteins within the secretory pathway. PMID:12351628

Hellman, Nathan E; Kono, Satoshi; Mancini, Grazia M; Hoogeboom, A J; De Jong, G J; Gitlin, Jonathan D

2002-11-29

337

Metallic copper as an antimicrobial surface.  

PubMed

Bacteria, yeasts, and viruses are rapidly killed on metallic copper surfaces, and the term "contact killing" has been coined for this process. While the phenomenon was already known in ancient times, it is currently receiving renewed attention. This is due to the potential use of copper as an antibacterial material in health care settings. Contact killing was observed to take place at a rate of at least 7 to 8 logs per hour, and no live microorganisms were generally recovered from copper surfaces after prolonged incubation. The antimicrobial activity of copper and copper alloys is now well established, and copper has recently been registered at the U.S. Environmental Protection Agency as the first solid antimicrobial material. In several clinical studies, copper has been evaluated for use on touch surfaces, such as door handles, bathroom fixtures, or bed rails, in attempts to curb nosocomial infections. In connection to these new applications of copper, it is important to understand the mechanism of contact killing since it may bear on central issues, such as the possibility of the emergence and spread of resistant organisms, cleaning procedures, and questions of material and object engineering. Recent work has shed light on mechanistic aspects of contact killing. These findings will be reviewed here and juxtaposed with the toxicity mechanisms of ionic copper. The merit of copper as a hygienic material in hospitals and related settings will also be discussed. PMID:21193661

Grass, Gregor; Rensing, Christopher; Solioz, Marc

2011-03-01

338

Accumulation of copper and other metals by copper-resistant plant-pathogenic and saprophytic pseudomonads  

SciTech Connect

Copper-resistant strains of Pseudomonas syringae carrying the cop operon produce periplasmic copper-binding proteins, and this sequestration outside the cytoplasm has been proposed as a resistance mechanism. In this study, strain PS61 of P. syringae carrying the cloned cop operon accumulated more total cellular copper than without the operon. Several other copper-resistant pseudomonads with homology to cop were isolated from plants, and these bacteria also accumulated copper. Two highly resistant species accumulated up to 115 to 120 mg of copper per g (dry weight) of cells. P. putida 08891 was more resistant to several metals than P. syringae pv. tomato PT23, but this increased resistance was not correlated with an increased accumulation of metals other than copper. Several metals were accumulated by both PT23 and P. putida, but when copper was added to induce the cop operon, there was generally no increase of accumulation of the other metals, suggesting that the cop operon does not contribute to accumulation of these other metals. The exceptions were aluminium for PT23 and iron for P. putida, which accumulated to higher levels when copper was added to the cultures. The results of this study support the role of copper sequestration in the copper resistance mechanism of P. syringae and suggest that this mechanism is common to several copper-resistant Pseudomonas species found on plants to which antimicrobial copper compounds are applied for plant disease control.

Cooksey, D.A.; Azad, H.R. (Univ. of California, Riverside (United States))

1992-01-01

339

"Pulling the plug" on cellular copper: The role of mitochondria in copper export  

PubMed Central

Mitochondria contain two enzymes, Cu, Zn superoxide dismutase (Sod1) and cytochrome c oxidase (CcO), that require copper as a cofactor for their biological activity. The copper used for their metallation originates from a conserved, bioactive pool contained within the mitochondrial matrix, the size of which changes in response to either genetic or pharmacological manipulation of cellular copper status. Its dynamic nature implies molecular mechanisms exist that functionally couple mitochondrial copper handling with other, extramitochondrial copper trafficking pathways. The recent finding that mitochondrial proteins with established roles in CcO assembly can also effect changes in cellular copper levels by modulating copper efflux from the cell supports a mechanistic link between organellar and cellular copper metabolism. However, the proteins and molecular mechanisms that link trafficking of copper to and from the organelle with other cellular copper trafficking pathways are unknown. This review documents our current understanding of copper trafficking to, and within, the mitochondrion for metallation of CcO and Sod1; the pathways by which the two copper centers in CcO are formed; and, the interconnections between mitochondrial function and the regulation of cellular copper homeostasis.

Leary, Scot C.; Winge, Dennis R.; Cobine, Paul A.

2014-01-01

340

Genetically encoded red fluorescent copper(I) sensors for cellular copper(I) imaging.  

PubMed

Copper ranks among the most important metal ions in living organism, owing to its key catalytic effect in a range of biochemical processes. Dysregulation of in vivo copper(I) metabolism is extremely toxic and would cause serious diseases in human, such as Wilson's and Menkes. Thus, it would be highly valuable to have a proper approach to monitor the dynamics of copper(I) in vivo, as it is directly related to the onset of human copper(I)-related diseases. Under these circumstance, developing fluorescent protein based copper(I) sensors is highly demanded. However, these established sensors are mostly based on green or yellow FPs. Fluorescent copper(I) sensors with a spectra in the red range are more desirable due to lower phototoxicity, less auto-fluorescent noise and better penetration of red light. In the present work, we grafted a special red FP into three different location of a copper(I) binding protein, and generate a series of red fluorescent copper(I) sensors. Despite their limited in vivo sensitivity toward copper(I), these sensors are viable for cellular copper(I) imaging. Furthermore, these red fluorescent copper(I) sensors are a good starting point to develop superior copper(I) biosensors capable of imaging copper(I) fluctuations within a truly biologically relevant concentration, and further effort to realize this endeavor is under way. PMID:24380863

Liang, Junyi; Guo, Lele; Ding, Yin; Xia, Lei; Shen, Yan; Qin, Meng; Xu, Qiang; Cao, Yi; Wang, Wei

2014-01-17

341

Development of window layer for high efficiency high bandgap cadmium selenide solar cell for 4-terminal tandem solar cell applications  

NASA Astrophysics Data System (ADS)

Tandem solar cells fabricated from thin films provide promise of improved efficiency while keeping the processing costs low. CdSe as top cell are investigated in this work. CIGS has been a standardized process with lab efficiencies reaching 18% [53]. This dissertation focuses on the development of conductive window layer for the development of a high performance, high bandgap solar cell. ZnSe, Cu2-xSe, and ZnSexTe1-x are investigated as viable window layers of the top cell. ZnSe in undoped form forms a good junction with CdSe films, but the Voc from these devices could never exceed the 360mV mark, while the current densities approached 17.5mA/cm2 [61].To improve Voc's, the high contact energy at the ZnSe/Cu interface has to be overcome by replacing Cu with a metal having higher work function or doping the window layer to form a tunneling contact with Copper. Deposition of ZnSe from binary sources in presence of nitrogen plasma resulted in films with proper stoichiometry. However, doping could not be accomplished. ZnTe is easily dopable, and was the next alternative. ZnTe doping in presence of Nitrogen plasma resulted in Zn rich films. Hence doping of the ternary compound ZnSexTe1-x was considered. This work focuses on studying the effects of compositional variation on the conductivity of the ZnSexTe1-x films. ZnSexTe1-x films were doped using Nitrogen. Films were deposited by co-evaporation from ZnTe, ZnSe and Se sources. Te/Se ratio was varied by varying the ZnTe thickness and Se Thickness. Films with Zn/Group VI ratio close to 1 were measured for conductivity using IV measurements. Highest conductivity of 2* 10 -8 O-cm was obtained at ZnSe, ZnTe, and Se thicknesses of 2000A, 1500A, and 500A respectively. The actual carrier concentration could be concealed by the current limiting Cu contacts. All films with Zn/Group VI ratio close to 1 showed slight conductivity in the 10-10 O-cm range. Layered ZnSexTe1-x Films doped with Nitrogen had targeted Zn/Group VI ratio of 1, but with a higher Te content. The films were also slightly conductive, in the 10-10 O-cm range. The mechanism limiting the doping in all the films seems to be the same.

Vakkalanka, Sridevi A.

342

Copper disinfection ban causes storm.  

PubMed

Since 1 February this year, under the EU's Biocidal Products Directive, it has been illegal to sell or use water treatment systems that use elemental copper, a practice employed historically by a significant number of UK healthcare facilities to combat Legionella. Alan Lester, managing director of specialist supplier of 'environmentally-friendly' water treatment systems, Advanced Hydro, says the ban has caused 'a storm of giant proportion,' with advocates of copper ion-based treatment systems arguing that this disinfection method dates back 3,000 years to Egyptian times, making it an 'undoubtedly proven' technology. Here he explains why the ban came into force, considers why the UK's Health and Safety Executive (HSE) is seeking a derogation, looks at the ban's likely impact, and gives a personal viewpoint on the 'pros and cons' of some of the alternative treatment technologies, including a titanium dioxide-based system marketed by Advanced Hydro itself in the UK. PMID:23763088

Lester, Alan

2013-05-01

343

Copper phthalocyanine nanoparticles and nanoflowers  

Microsoft Academic Search

Molecular organization of copper phthalocyanine (CuPc) thin films deposited at room temperature (30°C) on quartz and post annealed gold-coated quartz substrates have been studied. The thin films have been characterized by optical absorption, X-ray diffraction, atomic force microscopy and field emission scanning electron microscopy (FESEM). The FESEM images have shown densely packed nanoparticles and nanoflower like structure for the gold-coated

Santanu Karan; Dhrubajyoti Basak; Biswanath Mallik

2007-01-01

344

Solar cogeneration for copper smelting  

SciTech Connect

Work is reported on designing a system for solar repowering of a cogenerating flash smelting furnace that produces copper and sulfuric acid. Smelter energy requirements are listed and the proposed project is described. Several modifications to existing equipment and additional investment in the plant are listed that are necessary as a result of the solar power system improvement. Expected enhancements of the smelting process performance are discussed and the economics of the project are examined. (LEW)

Curto, P. (Gibbs and Hill, Inc., New York, NY); Gillespie, A.

1981-01-01

345

The system copper-tellurium  

NASA Astrophysics Data System (ADS)

The system copper-tellurium was investigated by DTA, DSC, and X-ray methods. A phase diagram with the phases Cu 2- xTe (33.5-36.2 mole% Te), Cu 3- xTe 2 (40-41 mole%), and CuTe was constructed. In the homogeneity ranges of the nonstoichiometric phases several superstructures were observed. The lattice parameters and d values of some of these phases are given.

Blachnik, R.; Lasocka, M.; Walbrecht, U.

1983-07-01

346

Activity of arsenic in copper  

Microsoft Academic Search

Values have been reported in the literature for the Henrian activity coefficient for arsenic in molten copper ranging from\\u000a 1.45 × 10-4 to 5 × 10-7 at temperatures between 1273 and 1573 K. In this study, that data was reexamined and was found to be in closer agreement\\u000a than originally reported. The Henrian activity coefficient was found to range from

D. C. Lynch

1980-01-01

347

Copper-Indium Alloy Transformations  

Microsoft Academic Search

Phase transformations of copper-indium alloy thin films are analyzed by hot-stage x-ray diffraction (XRD) over the temperature\\u000a range from 30 to 425 °C in controlled ambient. Thin films of Cu\\/In with a molar ratio of approximately 0.9 were used. In situ experiments were carried out in a reducing hydrogen atmosphere to minimize oxide formation. The as-deposited Cu\\/In alloy\\u000a transformed at

Nese Orbey; Robert W. Birkmire; T. W. Fraser Russell; Glover A. Jones

2000-01-01

348

Copper Metalization Using Electroplating Process  

NASA Astrophysics Data System (ADS)

Recently, electroplating method which deposits copper films by using cupric sulfate solution, has been proposed. The electroplating method has the advantages of simplicity, safety, low cost, low deposition temperature, high purity, low resistivity, and high capability of gap filling. In this method, an electrical contact is made to the seed layer and a current is passed such that the reaction ?Cu2++2e ? Cu(0)? occurs at the wafer surface (cathode). At the anode, an oxidation reaction occurs which balances the current flow at the cathode, thus maintaining electrical neutrality in the cupric sulfate solution. The seed layer used in this experiment was a copper thin film deposited using the sputtering method on p-type (100) silicon wafer using Ta thin film for barrier material. The thickness of seed and barrier layer were 400 and 600 Å respectively. The electroplating process was performed for 5min with a cathode current of 2A and a electrode distance of 4 cm. The intensity of magnetic field was about 200 400 Gauss. The pulse current generator was used for uniform surface and gap filling. The thickness and the sheet resistivity were measured using an ?-step profiler and 4-point probe system, respectively. Scanning electron microscopy (SEM) was used to investigate the film morphology and the surface grdin size of the plated copper films. X-rdy diffraction(XRD) was performed for the crystal texture. The impurity levels and atomic composition were determined using Auger electron spectroscopy (AES).

Park, Byung Nam; Choi, Sie Young

349

21 CFR 73.2125 - Potassium sodium copper chlorophyllin (chlorophyllin-copper complex).  

Code of Federal Regulations, 2010 CFR

...chlorophyllin (chlorophyllin-copper complex). 73.2125 Section 73.2125 ...chlorophyllin (chlorophyllin-copper complex). (a) Identity and specifications...carboxymethylcellulose. Tetrasodium pyrophosphate. Sorbitol. Magnesium phosphate, tribasic....

2009-04-01

350

21 CFR 73.2125 - Potassium sodium copper chlorophyllin (chlorophyllin-copper complex).  

Code of Federal Regulations, 2010 CFR

...chlorophyllin (chlorophyllin-copper complex). 73.2125 Section 73.2125 ...chlorophyllin (chlorophyllin-copper complex). (a) Identity and specifications...carboxymethylcellulose. Tetrasodium pyrophosphate. Sorbitol. Magnesium phosphate, tribasic....

2010-04-01

351

Evaluation of the Health Aspects of Copper Gluconate, Copper Sulfate, and Cuprous Iodide as Food Ingredients.  

National Technical Information Service (NTIS)

The report, by a group of qualified scientists designated the Select Committee of GRAS Substances (SCOGS), provides an independent evaluation of the safety of copper gluconate, copper sulfate, and cuprous iodide when used in foods at present or projected ...

1979-01-01

352

Determination of native ionic copper concentrations and copper complexation in peat soil extracts  

SciTech Connect

In acid peaty soils most of the copper in the soil solution is present as organic complexes. This paper describes methods for measuring total soil solution copper by flameless atomic absorption spectroscopy and estimating the proportion of this copper that is complexed using copper titration and a copper ion selective electrode. With these acidic peats of diverse origin, total copper in solution at natural pH values (3.4 to 3.5) ranged from 0.14 to 0.2 ..mu.. M. Of this, 60 to 90% was complexed. Raising the pH of aqueous extracts to about 6.0 increased the degree of complexation of soluble copper in extracts of all three peats to > 98%. The results are discussed in relation to current thinking about the nature of copper complexation by humic and fulvic acids. 18 references, 5 figures, 2 tables.

Kerven, G.L.; Edwards, D.G.; Asher, C.J.

1984-02-01

353

Copper - A Metal for the Ages  

USGS Publications Warehouse

Copper was one of the first metals ever extracted and used by humans, and it has made vital contributions to sustaining and improving society since the dawn of civilization. Copper was first used in coins and ornaments starting about 8000 B.C., and at about 5500 B.C., copper tools helped civilization emerge from the Stone Age. The discovery that copper alloyed with tin produces bronze marked the beginning of the Bronze Age at about 3000 B.C. Copper is easily stretched, molded, and shaped; is resistant to corrosion; and conducts heat and electricity efficiently. As a result, copper was important to early humans and continues to be a material of choice for a variety of domestic, industrial, and high-technology applications today.

Doebrich, Jeff

2009-01-01

354

Copper sulfides by chemical spray pyrolysis process  

NASA Astrophysics Data System (ADS)

The chemistry of formation of copper sulfide and copper indium disulfide films by the chemical spray pyrolysis process has been investigated. It was established that the formation of copper sulfide films by the spray process of water solutions of CuCl2 and SC(NH2)2 passes through the stage of formation of intermediate complex compound Cu(SCN2H4)Cl·H2O in the initial solution. Thermal behaviour studies in air exhibit rearrangement of the complex at temperatures higher than 210 °C with formation of copper sulfide. Copper oxide is the decomposition product at temperatures higher than 700 °C in air. CuInS2 is formed by the reaction between copper and indium sulfides.

Krunks, M.; Mellikov, E.; Bijakina, O.

1997-01-01

355

Synthesis and characterization of quaternary selenides Sn 2Pb 5Bi 4Se 13 and Sn 8.65Pb 0.35Bi 4Se 15  

NASA Astrophysics Data System (ADS)

Quaternary selenides Sn 2Pb 5Bi 4Se 13 and Sn 8.65Pb 0.35Bi 4Se 15 were synthesized from the elements in sealed silica tubes; their crystal structures were determined by single-crystal and powder X-ray diffraction. Both compounds crystallize in monoclinic space group C2/ m (No.12), with lattice parameters of Sn 2Pb 5Bi 4Se 13: a = 14.001(6) Å, b = 4.234(2) Å, c = 23.471(8) Å, V = 1376.2(1) Å 3, R1/ wR2 = 0.0584/0.1477, and GOF = 1.023; Sn 8.65Pb 0.35Bi 4Se 15: a = 13.872(3) Å, b = 4.2021(8) (4) Å, c = 26.855(5) Å, V = 1557.1(5) Å 3, R1/ wR2 = 0.0506/0.1227, and GOF = 1.425. These compounds exhibit tropochemical cell-twinning of NaCl-type structures with lillianite homologous series L(4, 5) and L(4, 7) for Sn 2Pb 5Bi 4Se 13 and Sn 8.65Pb 0.35Bi 4Se 15, respectively. Measurements of electrical conductivity indicate that these materials are semiconductors with narrow band gaps; Sn 2Pb 5Bi 4Se 13 is n-type, whereas Sn 8.65Pb 0.35Bi 4Se 15 is a p-type semiconductor with Seebeck coefficients -80(5) and 178(7) ?V/K at 300 K, respectively.

Chen, Kuei-Bo; Lee, Chi-Shen

2009-09-01

356

Electronic Characterization of Defects in Narrow Gap Semiconductors-Comparison of Electronic Energy Levels and Formation Energies in Mercury Cadmium Telluride, Mercury Zinc Telluride, and Mercury Zinc Selenide  

NASA Technical Reports Server (NTRS)

We have used a Green's function technique to calculate the energy levels and formation energy of deep defects in the narrow gap semiconductors mercury cadmium telluride (MCT), mercury zinc telluride (MZT) and mercury zinc selenide (MZS). The formation energy is calculated from the difference between the total energy with an impurity cluster and the total energy for the perfect crystal. Substitutional (including antisite), interstitial (self and foreign), and vacancy deep defects are considered. Relaxation effects are calculated (with molecular dynamics). By use of a pseudopotential, we generalize the ideal vacancy model so as to be able to consider relaxation for vacancies. Different charge states are considered and the charged state energy shift (as computed by a modified Haldane-Anderson model) can be twice that due to relaxation. Different charged states for vacancies were not calculated to have much effect on the formation energy. For all cases we find deep defects in the energy gap only for cation site s-like orbitals or anion site p-like orbitals, and for the substitutional case only the latter are appreciably effected by relaxation. For most cases for MCT, MZT, MZS, we consider x (the concentration of Cd or Zn) in the range appropriate for a band gap of 0.1 eV. For defect energy levels, the absolute accuracy of our results is limited, but the precision is good, and hence chemical trends are accurately predicted. For the same reason, defect formation energies are more accurately predicted than energy level position. We attempt, in Appendix B, to calculate vacancy formation energies using relatively simple chemical bonding ideas due to Harrison. However, these results are only marginally accurate for estimating vacancy binding energies. Appendix C lists all written reports and publications produced for the grant. We include abstracts and a complete paper that summarizes our work which is not yet available.

Patterson, James D.

1996-01-01

357

Functionalization based on the substitutional flexibility: strong middle IR nonlinear optical selenides AX(II)(4)X(III)(5)Se12.  

PubMed

Seven nonlinear optical (NLO) active selenides in the middle IR region, AX(II)4X(III)5Se12 (A = K(+)-Cs(+); X(II) = Mn(2+), Cd(2+); X(III) = Ga(3+), In(3+)) adopting the KCd4Ga5S12-type structure, have been synthesized by high-temperature solid-state reaction of an elemental mixture with ACl flux. Their three-dimensional network structures are stacked by M9Se24-layers of vertex sharing MSe4 tetrahedra, of which each center is jointly occupied by X(II) and X(III) atoms. Studies suggest that such tetrahedral building units can be regarded as the "multi-functional sites", on which the Cd(2+)/Ga(3+) pair gives rise to the coexistence of NLO and thermochromic properties, and the Mn(2+)/In(3+) pair leads to the coexistence of NLO and magnetic properties. The density functional theory (DFT) studies and the cutoff-energy-dependent NLO coefficient analyses reveal that such "multi-functional sites" contribute to the origin of the second harmonic generation (SHG) that is ascribed to the electronic transitions from the Se-4p states to the ns, np states of X(II) and X(III) atoms. Remarkably, title compounds show very strong SHG at an incident wavelength of 2.05 ?m, roughly 16-40 times that of commercial AgGaS2; among them, ACd4In5Se12 (A = Rb, Cs) represents the strongest SHG among chalcogenides to date. PMID:23902474

Lin, Hua; Chen, Ling; Zhou, Liu-Jiang; Wu, Li-Ming

2013-08-28

358

Radiolytic synthesis and spectroscopic investigations of cadmium selenide quantum dots grown in cationic surfactant based quaternary water-in-oil microemulsions.  

PubMed

Cadmium selenide (CdSe) quantum dots (QDs) were grown in cationic surfactant cetyltrimethylammonium bromide (CTAB) based water-in-oil microemulsions using high-energy electron beam irradiation. The sizes of the primary QDs were determined from the absorption spectra as well as from high-resolution transmission electron microscope images and were found to be within 3 nm. Effects of experimental parameters, such as w0 (molar ratio of water to surfactant in a microemulsion) values and precursor concentrations on the optical properties of these QDs were investigated in detail. The QDs exhibited broad photoluminescence (PL) in the wavelength region extending from 450 to 750 nm at room temperature. The time-resolved PL showed multiexponential decay and the average lifetime was estimated to be 4.1 ns and the PL decay curve analysis indicated the presence of predominating trap state emission from the as obtained CdSe QDs. The quantum yield exhibited by as-grown QDs was determined to be 2.4%, without involving any postprocessing techniques. However, these QDs possessing ultra small size (?5 nm) were found to exhibit CIE (Commission Internationale d'Eclairage) chromaticity x, y co-ordinates close to (0.36,0.36), which confirms their potential as white light emitters. Besides, their light emitting color tunability can be conveniently achieved just by varying the experimental parameters. Therefore, the present method employing electron beam irradiation, accompanied by various advantages of CTAB based water-in-oil microemulsion as the host matrix, offers a simple and one step method to obtain CdSe QDs possessing potential applications in white light emitting devices. PMID:23489608

Singh, S; Guleria, A; Singh, A K; Rath, M C; Adhikari, S; Sarkar, S K

2013-05-15

359

Electroless deposition of copper and fabrication of copper micropatterns on CVD diamond film surfaces  

Microsoft Academic Search

Electroless deposition of copper on as-grown and amino-modification diamond substrates was investigated. The compact and uniform copper films were successfully electrolessly deposited on as-grown and amino-modification diamond substrates after activation by Pd\\/Sn colloid nanoparticles. The adhesion interaction between copper films and diamond substrates was roughly estimated by the ultrasonic treatment. The results showed the higher adhesion interaction between copper films

Jianwen Zhao; Ruhai Tian; Jinfang Zhi

2008-01-01

360

Copper-inducible transcriptional regulation at two promoters in the Escherichia coli copper resistance determinant pco  

Microsoft Academic Search

The pco determinant of Escherichia coli plasmid pRJ1004 encodes inducible resistance to the trace element copper. The identification of two copper- dependent transcriptional initiation regions within pco that each contain a similar upstream hyphenated dyad motif is described. Deletion constructs showed that this 'copper box' motif was essential for copper-inducible activity at both pco promoters, PpcoA and PpcoE. The placement

D. A. Rouch; N. L. Brown

1997-01-01

361

Advantages and challenges of increased antimicrobial copper use and copper mining  

Microsoft Academic Search

Copper is a highly utilized metal for electrical, automotive, household objects, and more recently as an effective antimicrobial\\u000a surface. Copper-containing solutions applied to fruits and vegetables can prevent bacterial and fungal infections. Bacteria,\\u000a such as Salmonellae and Cronobacter sakazakii, often found in food contamination, are rapidly killed on contact with copper alloys. The antimicrobial effectiveness of\\u000a copper alloys in the

Jutta Elguindi; Xiuli Hao; Yanbing Lin; Hend A. Alwathnani; Gehong Wei; Christopher Rensing

362

Effect of Stainless Steel on Corrosion Behavior of Copper in a Copper-bearing Intrauterine Device  

Microsoft Academic Search

Some copper-bearing intrauterine devices (Cu-IUDs) consist of pure copper and stainless steel. Corrosion of copper in the Cu-IUD was anticipated to be affected by galvanic action due to electrical contact between these two metals. Electrochemical measurements were carried out in physiological saline with or without indomethacin, which was introduced for bleeding control. In the copper\\/stainless steel couple, the open-circuit potential

H. Xue; N. Xu; C. Zhang

1998-01-01

363

Copper aluminate spinel in the stabilization and detoxification of simulated copper-laden sludge  

Microsoft Academic Search

This study aims to evaluate the feasibility of stabilizing copper-laden sludge by the application of alumina-based ceramic products. The processing temperature, material leaching behaviour, and the effect of detoxification were investigated in detail. CuO was used to simulate the copper-laden sludge and X-ray Diffraction was performed to monitor the incorporation of copper into the copper aluminate spinel (CuAl2O4) phase in

Yuanyuan Tang; Kaimin Shih; King Chan

2010-01-01

364

Effect of copper seed aging on electroplating-induced defects in copper interconnects  

Microsoft Academic Search

Voids in copper thin films, observed after electroplating, have been linked to seed aging that occurs when a wafer is exposed,\\u000a over time, to clean-room ambient. Oxidation of the copper seed surface prevents wetting during subsequent copper electroplating,\\u000a leading to voids. Several surface treatments were employed to counteract the seed aging effect, including reduction of the\\u000a copper oxide film by

Daniele Contestable-Gilkes; Deepak Ramappa; Minseok Oh; Sailesh M. Merchant

2002-01-01

365

Cobalt distribution during copper matte smelting  

Microsoft Academic Search

Many smelter operators subscribe to the “precautionary principle” and wish to understand the behavior of the metals and impurities\\u000a during smelting, especially how they distribute between product and waste phases and whether these phases lead to environmental,\\u000a health, or safety issues. In copper smelting, copper and other elements are partitioned between copper matte, iron silicate\\u000a slag, and possibly the waste

T. S. Kho; D. R. Swinbourne; T. Lehner

2006-01-01

366

Diffusion of copper into gold plating  

Microsoft Academic Search

The value of the room-temperature copper-gold interdiffusion coefficient derived by extrapolating from high-temperature measurements is an underestimate by several orders of magnitude. Plating copper with a gold film has several disadvantages. Two specimens were analyzed by using Auger electron spectroscopy. Once the full thickness of the gold film is penetrated, copper accumulates on the surface, and a layer of high

Sunchana P. Pucic

1993-01-01

367

Carbon monoxide oxidation over three different oxidation states of copper: Metallic copper, copper (I) oxide, and copper (II) oxide - a surface science and kinetic study  

Microsoft Academic Search

Reaction rates and activation energies were measured for carbon monoxide oxidation over thin films of metallic copper, copper (I) oxide, and copper (II) oxide grown on graphite. The reactions were carried out in the temperature range 200-350[degrees]C at total pressures of 100 Torr. Auger Electron Spectroscopy (AES) and X-ray Photoelectron Spectroscopy (XPS) were used to characterize the growth and oxidation

G. G. Jernigan; G. A. Somorjai

1994-01-01

368

Copper radionuclides and radiopharmaceuticals in nuclear medicine  

Microsoft Academic Search

The chemistry, radiochemistry, radiobiology, and radiopharmacology of radiopharmaceuticals containing copper radionuclides are reviewed. Copper radionuclides offer application in positron emission tomography, targeted radiotherapy, and single photon imaging. The chemistry of copper is relatively simple and well-suited to radiopharmaceutical application. Current radiopharmaceuticals include biomolecules labelled via bifunctional chelators primarily based on cyclic polyaminocarboxylates and polyamines, and pyruvaldehyde-bis(N4-methylthiosemicarbazone) (PTSM) and its analogues.

Philip J. Blower; Jason S. Lewis; Jamal Zweit

1996-01-01

369

Copper chloride cathode for a secondary battery  

NASA Technical Reports Server (NTRS)

Higher energy and power densities are achieved in a secondary battery based on molten sodium and a solid, ceramic separator such as a beta alumina and a molten catholyte such as sodium tetrachloroaluminate and a copper chloride cathode. The higher cell voltage of copper chloride provides higher energy densities and the higher power density results from increased conductivity resulting from formation of copper as discharge proceeds.

Bugga, Ratnakumar V. (inventor); Distefano, Salvador (inventor); Nagasubramanian, Ganesan (inventor); Bankston, Clyde P. (inventor)

1990-01-01

370

Effects of dietary supplementation with copper sulfate or tribasic copper chloride on broiler performance, relative copper bioavailability, and oxidation stability of vitamin E in feed.  

PubMed

An experiment was conducted using a total of 420, 1-d-old, Arbor Acres commercial male chicks to compare copper sulfate and tribasic copper chloride (TBCC) as sources of supplemental copper for broilers. Chicks were randomly allotted to 1 of 7 treatments for 6 replicates of 10 birds each and were fed a basal corn-soybean meal diet (11.45 mg/kg copper) supplemented with 0, 150, 300, or 450 mg/kg copper from copper sulfate or TBCC for 21 d. Chicks fed 450 mg/kg copper as copper sulfate had lower (P < 0.01) average daily feed intake and average daily gain than those consuming other diets. Feeding supplemental copper increased linearly (P < 0.0001) liver copper concentrations regardless of copper source. The slopes of regressions of log10 liver copper on different independent variables used in regressions differ (P < 0.05) between the 2 copper sources. Linear regression over nonzero dietary levels of log10 transformed liver copper concentration on added copper intake resulted in a slope ratio estimate of 109.0 +/- 3.4% (with a 95% confidence interval from 102.2 to 115.8) for bioavailability of copper from TBCC compared with 100 for that in copper sulfate. When the feeds were stored at room temperature for 10 or 21 d, the vitamin E content in the feed fortified with 300 mg/kg copper as TBCC was higher (P < 0.01) than that in the feed added with 300 mg/kg copper as CuSO4. The vitamin E contents in liver and plasma of broilers given TBCC were also higher (P < 0.01) than those of birds fed copper sulfate. The results from this study indicate that TBCC is a safer product and more available to broilers than copper sulfate, and it is chemically less active than copper sulfate in promoting the oxidation of vitamin E in feed. PMID:15971525

Luo, X G; Ji, F; Lin, Y X; Steward, F A; Lu, L; Liu, B; Yu, S X

2005-06-01

371

Copper accumulation and oxidative stress in the sea anemone, Aiptasia pallida, after waterborne copper exposure  

Microsoft Academic Search

Copper is a common marine pollutant yet its effects on symbiotic cnidarians are largely understudied. To further understand the impact of elevated copper concentrations on marine symbiotic organisms, toxicity tests were conducted using the model sea anemone, Aiptasia pallida, with and without its zooxanthellae symbiont. Symbiotic and aposymbiotic A. pallida were exposed to sublethal copper concentrations (0, 5, 15, and

W. P. L. Main; C. Ross; G. K. Bielmyer

2010-01-01

372

XIAP Is a Copper Binding Protein Deregulated in Wilson's Disease and Other Copper Toxicosis Disorders  

Microsoft Academic Search

Summary X-linked inhibitor of apoptosis (XIAP), known primarily for its caspase inhibitory properties, has recently been shown to interact with and regulate the levels of COMMD1, a protein associated with a form of canine copper toxicosis. Here, we describe a role for XIAP in copper metabolism. We find that XIAP levels are greatly reduced by intracellular copper accumulation in Wilson's

Arjmand R. Mufti; Ezra Burstein; Rebecca A. Csomos; Paul C. F. Graf; John C. Wilkinson; Robert D. Dick; Madhavi Challa; Jae-Kyoung Son; Shawn B. Bratton; Grace L. Su; George J. Brewer; Ursula Jakob; Colin S. Duckett

2006-01-01

373

Wetting and infiltration of zirconium diboride by copper and copper\\/boron alloys  

Microsoft Academic Search

Purpose – This paper investigates wetting and infiltration of zirconium diboride by copper and copper\\/boron alloys in order to more effectively create electrodes for electrical discharge machining. Design\\/methodology\\/approach – A high temperature furnace outfitted with a video recording system was utilized to observe wetting angles between molten copper alloys and zirconium diboride at various temperatures. A parallel, investigation of the

Brent E. Stucker; Walter L. Bradley

2006-01-01

374

Synergistic effects of corrosion inhibitors for copper and copper alloy archaeological artefacts  

Microsoft Academic Search

Benzotriazole (BTA) is one of the most widespread treatments used at present for the stabilisation of bronze disease. Unfortunately, BTA does not always work effectively when applied to heavily corroded copper and copper alloy archaeological artefacts. Combinations of corrosion inhibitors are extensively used in industry to retard copper corrosion. When two or more corrosion inhibitors are used, the inhibition efficiency

S. Golfomitsou; J. F. Merkel

2004-01-01

375

Radioactivity at the Copper Creek copper lode prospect, Eagle district, east-central Alaska  

USGS Publications Warehouse

Investigation of radioactivity anomalies at the Copper Creek copper lode prospect, Eagle district, east-central Alaska, during 1949 disclosed that the radioactivity is associated with copper mineralization in highly metamorphosed sedimentary rocks. These rocks are a roof pendant in the Mesozoic "Charley River" batholith. The radioactivity is probably all due to uranium associated with bornite and malachite.

Wedow, Helmuth; Tolbert, Gene Edward

1952-01-01

376

Runoff rates, chemical speciation and bioavailability of copper released from naturally patinated copper  

Microsoft Academic Search

The release of copper, induced by atmospheric corrosion, from naturally patinated copper of varying age (0 and 30 years) has been investigated together with its potential ecotoxic effect. Results were generated in an interdisciplinary research effort in which corrosion science and ecotoxicology aspects were combined. The aim of the investigation was to elucidate the situation when copper-containing rainwater leaves a

C Karlén; I Odnevall Wallinder; D Heijerick; C Leygraf

2002-01-01

377

Humic acid complexation of calcium and copper  

SciTech Connect

High-affinity metal binding by isolated humic acids has been observed for both copper and calcium in metal titration experiments. Results of titration of humic acids with a single metal (either calcium or copper) are consistent with a discrete ligand site model of humate-metal binding. However, copper titrations in the presence of excess calcium do not show competitive effects predicted by such a model. Hence, different ligand sites must be involved in calcium and copper binding, or a binding mechanism other than discrete ligand binding must be operative.

Hering, J.G.; Morel, F.M.M.

1984-10-01

378

Information Profiles on Potential Occupational Hazards: Copper and Compounds.  

National Technical Information Service (NTIS)

Information is provided on inorganic copper compounds, which have an annual production of at least 1 million pounds, and for organic copper compounds, with an annual production of at least 100,000 pounds. These compounds include: copper (7440508), metal, ...

1982-01-01

379

19 CFR 10.98 - Copper-bearing fluxing material.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Copper-bearing fluxing material. 10.98...Provisions Fluxing Material § 10.98 Copper-bearing fluxing material. ...contain by weight not over 15 percent copper. (b) [Reserved] (c)...

2013-04-01

380

21 CFR 73.125 - Sodium copper chlorophyllin.  

Code of Federal Regulations, 2010 CFR

... Foods § 73.125 Sodium copper chlorophyllin. (a) Identity...1) The color additive sodium copper chlorophyllin is a green to black powder prepared from chlorophyll by...and replacement of magnesium by copper. Chlorophyll is extracted...

2009-04-01

381

21 CFR 73.125 - Sodium copper chlorophyllin.  

Code of Federal Regulations, 2010 CFR

... Foods § 73.125 Sodium copper chlorophyllin. (a) Identity...1) The color additive sodium copper chlorophyllin is a green to black powder prepared from chlorophyll by...and replacement of magnesium by copper. Chlorophyll is extracted...

2010-04-01

382

Surface structure influences contact killing of bacteria by copper  

PubMed Central

Copper kills bacteria rapidly by a mechanism that is not yet fully resolved. The antibacterial property of copper has raised interest in its use in hospitals, in place of plastic or stainless steel. On the latter surfaces, bacteria can survive for days or even weeks. Copper surfaces could thus provide a powerful accessory measure to curb nosocomial infections. We here investigated the effect of the copper surface structure on the efficiency of contact killing of Escherichia coli, an aspect which so far has received very little attention. It was shown that electroplated copper surfaces killed bacteria more rapidly than either polished copper or native rolled copper. The release of ionic copper was also more rapid from electroplated copper compared to the other materials. Scanning electron microscopy revealed that the bacteria nudged into the grooves between the copper grains of deposited copper. The findings suggest that, in terms of contact killing, more efficient copper surfaces can be engineered.

Zeiger, Marco; Solioz, Marc; Edongue, Hervais; Arzt, Eduard; Schneider, Andreas S

2014-01-01

383

Surface structure influences contact killing of bacteria by copper.  

PubMed

Copper kills bacteria rapidly by a mechanism that is not yet fully resolved. The antibacterial property of copper has raised interest in its use in hospitals, in place of plastic or stainless steel. On the latter surfaces, bacteria can survive for days or even weeks. Copper surfaces could thus provide a powerful accessory measure to curb nosocomial infections. We here investigated the effect of the copper surface structure on the efficiency of contact killing of Escherichia coli, an aspect which so far has received very little attention. It was shown that electroplated copper surfaces killed bacteria more rapidly than either polished copper or native rolled copper. The release of ionic copper was also more rapid from electroplated copper compared to the other materials. Scanning electron microscopy revealed that the bacteria nudged into the grooves between the copper grains of deposited copper. The findings suggest that, in terms of contact killing, more efficient copper surfaces can be engineered. PMID:24740976

Zeiger, Marco; Solioz, Marc; Edongué, Hervais; Arzt, Eduard; Schneider, Andreas S

2014-06-01

384

Dietary copper intake influences skin lysyl oxidase in young men  

Microsoft Academic Search

The effect of low dietary copper on copper status and the copper-containing enzyme lysyl oxidase was studied in young men. The study was divided into three dietary periods. During the first period, subjects were fed 0.66 mg\\/day Cu for 24 days (marginal copper). The level of copper was dropped to 0.38 mg\\/day for the next 42 days (low copper) and

Moshe J. Werman; Sam J. Bhathena; Judith R. Turnlund

1997-01-01

385

Energy and materials flows in the copper industry  

SciTech Connect

The copper industry comprises both the primary copper industry, which produces 99.9%-pure copper from copper ore, and the secondary copper industry, which salvages and recycles copper-containing scrap metal to extract pure copper or copper alloys. The United States uses about 2 million tons of copper annually, 60% of it for electrical applications. Demand is expected to increase less than 4% annually for the next 20 years. The primary copper industry is concentrated in the Southwest; Arizona produced 66% of the 1979 total ore output. Primary production uses about 170 x 10/sup 12/ Btu total energy annually (about 100 x 10/sup 6/ Btu/ton pure copper produced from ore). Mining and milling use about 60% of the total consumption, because low-grade ore (0.6% copper) is now being mined. Most copper is extracted by smelting sulfide ores, with concomitant production of sulfur dioxide. Clean air regulations will require smelters to reduce sulfur emissions, necessitating smelting process modifications that could also save 20 x 10/sup 12/ Btu (10 x 10/sup 6/ Btu/ton of copper) in smelting energy. Energy use in secondary copper production averages 20 x 10/sup 6/ Btu/ton of copper. If all copper products were recycled, instead of the 30% now salvaged, the energy conservation potential would be about one-half the total energy consumption of the primary copper industry.

Gaines, L.L.

1980-12-01

386

National Park Service Interpretation Center looking south Kennecott Copper ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

National Park Service Interpretation Center looking south - Kennecott Copper Corporation, NPS Interpretation Building, On Copper River & Northwestern Railroad, Kennicott, Valdez-Cordova Census Area, AK

387

The significance of copper chelators in clinical and experimental application.  

PubMed

The essentiality and redox-activity of copper make it indispensable in the mammalian system. However, a comprehensive understanding of copper metabolism and function has not been achieved. Copper chelators have been used as an approach to provide insights into copper acquisition, distribution, and disposition at both the cellular and organism level. Unfortunately, the understanding of effective copper chelators is predominantly based upon their chemical structures and their reactions with copper. The understanding of the efficacy of copper chelators in the biological system has been equivocal, thereby leading to under- or misleading-utilization of these agents in clinical and experimental approaches. Current use of copper chelators in vivo almost exclusively either limits the availability or focuses on the removal of copper in mammalian organ system. There are at least two aspects of copper chelators that are yet to be explored. First, copper chelators preferentially bind either cuprous or cupric. As a result, they potentially modulate copper redox-activity without removing copper from the system. Second, copper chelators are characterized as either membrane-permeable or -impermeable, thus would serve as an organ-selective copper delivery or deprivation system to manipulate the biological function of copper. Here we review clinically relevant copper chelators that have been experimentally or clinically studied for their role in manipulation of copper metabolism and function, paying critical attention to potentially more valuable usage of these agents. PMID:21109416

Ding, Xueqin; Xie, Huiqi; Kang, Y James

2011-04-01

388

Synthesis of Commercial Products from Copper Wire-Drawing Waste  

NASA Astrophysics Data System (ADS)

Copper powder and copper sulfate pentahydrate were obtained from copper wire-drawing scale. The hydrometallurgical recycling process proposed in this article yields a high-purity copper powder and analytical grade copper sulfate pentahydrate. In the first stage of this process, the copper is dissolved in sulfuric acid media via dismutation of the scale. In the second stage, copper sulfate pentahydrate is precipitated using ethanol. Effects such as pH, reaction times, stirring speed, initial copper concentration, and ethanol/solution volume ratio were studied during the precipitation from solution reaction. The proposed method is technically straightforward and provides efficient recovery of Cu from wire-drawing scale.

Ayala, J.; Fernández, B.

2014-06-01

389

Synthesis of Commercial Products from Copper Wire-Drawing Waste  

NASA Astrophysics Data System (ADS)

Copper powder and copper sulfate pentahydrate were obtained from copper wire-drawing scale. The hydrometallurgical recycling process proposed in this article yields a high-purity copper powder and analytical grade copper sulfate pentahydrate. In the first stage of this process, the copper is dissolved in sulfuric acid media via dismutation of the scale. In the second stage, copper sulfate pentahydrate is precipitated using ethanol. Effects such as pH, reaction times, stirring speed, initial copper concentration, and ethanol/solution volume ratio were studied during the precipitation from solution reaction. The proposed method is technically straightforward and provides efficient recovery of Cu from wire-drawing scale.

Ayala, J.; Fernández, B.

2014-03-01

390

Geomorphology of the lower Copper River, Alaska  

USGS Publications Warehouse

The Copper River, located in southcentral Alaska, drains an area of more than 24,000 square miles. About 30 miles above its mouth, this large river enters Miles Lake, a proglacial lake formed by the retreat of Miles Glacier. Downstream from the outlet of Miles Lake, the Copper River flows past the face of Childs Glacier before it enters a large, broad, alluvial flood plain. The Copper River Highway traverses this flood plain and in 1995, 11 bridges were located along this section of the highway. These bridges cross parts of the Copper River and in recent years, some of these bridges have sustained serious damage due to the changing course of the Copper River. Although the annual mean discharge of the lower Copper River is 57,400 cubic feet per second, most of the flow occurs during the summer months from snowmelt, rainfall, and glacial melt. Approximately every six years, an outburst flood from Van Cleve Lake, a glacier-dammed lake formed by Miles Glacier, releases approximately 1 million acre-feet of water into the Copper River. When the outflow rate from Van Cleve Lake reaches it peak, the flow of the Copper River will increase between 150,000 to 190,000 cubic feet per second. Data collected by bedload sampling and continuous seismic reflection indicated that Miles Lake traps virtually all the bedload being transported by the Copper River as it enters the lake from the north. The reservoir-like effect of Miles Lake results in the armoring of the channel of the Copper River downstream from Miles Lake, past Childs Glacier, until it reaches the alluvial flood plain. At this point, bedload transport begins again. The lower Copper River transports 69 million tons per year of suspended sediment, approximately the same quantity as the Yukon River, which drains an area of more than 300,000 square miles. By correlating concurrent flows from a long-term streamflow-gaging station on the Copper River with a short-term streamflow-gaging station at the outlet of Miles Lake, long-term flow characteristics of the lower Copper River were synthesized. Historical discharge and cross-section data indicate that as late as 1970, most of the flow of the lower Copper River was through the first three bridges of the Copper River Highway as it begins to traverse the alluvial flood plain. In the mid 1980's, a percentage of the flow had shifted away from these three bridges and in 1995, only 51 percent of the flow of the Copper River passed through them. Eight different years of aerial photography of the lower Copper River were analyzed using Geographical Information System techniques. This analysis indicated that no major channel changes were caused by the 1964 earthquake. However, a flood in 1981 that had a recurrence interval of more than 100 years caused significant channel changes in the lower Copper River. A probability analysis of the lower Copper River indicated stable areas and the long-term locations of channels. By knowing the number of times a particular area has been occupied by water and the last year an area was occupied by water, areas of instability can be located. A Markov analysis of the lower Copper River indicated that the tendency of the flood plain is to remain in its current state. Large floods of the magnitude of the 1981 event are believed to be the cause of major changes in the lower Copper River.

Brabets, Timothy P.

1997-01-01

391

Geomorphology of the lower Copper River, Alaska  

USGS Publications Warehouse

The Copper River, located in southcentral Alaska, drains an area of more than 24,000 square miles. About 30 miles above its mouth, this large river enters Miles Lake, a proglacial lake formed by the retreat of Miles Glacier. Downstream from the outlet of Miles Lake, the Copper River flows past the face of Childs Glacier before it enters a large, broad, alluvial flood plain. The Copper River Highway traverses this flood plain and in 1996, 11 bridges were located along this section of the highway. These bridges cross parts or all of the Copper River and in recent years, some of these bridges have sustained serious damage due to the changing course of the Copper River. Although the annual mean discharge of the lower Copper River is 57,400 cubic feet per second, most of the flow occurs during the summer months from snowmelt, rainfall, and glacial melt. Approximately every six years, an outburst flood from Van Cleve Lake, a glacier-dammed lake formed by Miles Glacier, releases approximately 1 million acre-feet of water into the Copper River. At the peak outflow rate from Van Cleve Lake, the flow of the Copper River will increase an additional 140,000 and 190,000 cubic feet per second. Bedload sampling and continuous seismic reflection were used to show that Miles Lake traps virtually all the bedload being transported by the Copper River as it enters the lake from the north. The reservoir-like effect of Miles Lake results in the armoring of the channel of the Copper River downstream from Miles Lakes, past Childs Glacier, until it reaches the alluvial flood plain. At this point, bedload transport begins again. The lower Copper River transports 69 million tons per year of suspended sediment, approximately the same quantity as the Yukon River, which drains an area of more than 300,000 square miles. By correlating concurrent flows from a long-term streamflow- gaging station on the Copper River with a short-term streamflow-gaging station at the outlet of Miles Lake, long-term flow characteristics of the lower Copper River were synthesized. Historical discharge and cross-section data indicate that as late as 1970, most of the flow of the lower Copper River was through the first three bridges of the Copper River Highway as it begins to traverse the alluvial flood plain. In the mid 1980's, a percentage of the flow had shifted away from these three bridges and in 1995, only 51 percent of the flow of the Copper River passed through them. Eight different years of aerial photography of the lower Copper River were analyzed using Geographical Information System techniques. This analysis indicated that no major channel changes were caused by the 1964 earthquake. A flood in 1981 that had a recurrence interval of more than 100 years caused significant channel changes in the lower Copper River. A probability analysis of the lower Copper River indicated stable areas and the long-term locations of channels. By knowing the number of times a particular area has been occupied by water and the last year an area was occupied by water, areas of instability can be located. A Markov analysis of the lower Copper River indicated that the tendency of the flood plain is to remain in its current state. Large floods of the magnitude of the 1981 event are believed to be the cause of major changes in the lower Copper River.

Brabets, T. P.

1996-01-01

392

Tear copper and its association with liver copper concentrations in six adult ewes.  

PubMed Central

Tear and liver copper concentrations from 6 clinically healthy adult mixed-breed ewes were measured by Atomic Absorption Electrothermal Atomization (graphite furnace) Spectrometry and Flame Absorption Spectrometry, respectively, 7 times over 227 d to determine if their tears contained copper and if so, whether tear copper concentrations could reliably predict liver copper concentrations. To produce changes in liver copper concentration, the diet was supplemented with copper at concentrations that increased from 23 mg to 45 mg Cu/kg feed/day/sheep during the study. This regimen raised liver copper for all sheep to potentially toxic hepatic tissue concentration of greater than 500 mg/kg dry (DM) matter (tissue). The results of the study showed that copper was present in the tears of all sheep. The mean tear copper concentration showed a positive correlation with liver copper concentration (P = 0.003), increasing from 0.07 mg/kg DM at the start to 0.44 mg/kg DM at the end of the study, but could not reliably predict liver copper concentration (R2 = 0.222).

Schoster, J V; Stuhr, C; Kiorpes, A

1995-01-01

393

Initiation of electroless nickel plating on copper, palladium-activated copper, gold, and platinum  

SciTech Connect

The catalytic activity of copper, palladium-activated copper, gold, and platinum for electro-oxidation of hypophosphite and electroless nickel plating was investigated in an ammoniacal solution of pH 8.8 at 50/sup 0/C by potential measurements and linear sweep voltammetry from -0.3 to -0.92V vs. SCE. Early stages of nickel plating on copper-palladium substrates were studied by scanning electron microscopy in conjunction with EDAX. It was found that palladium-activated copper and gold were catalytically active in the entire range of potentials examined; copper was active below -0.6 platinum was not active at all. Small amounts of electrolytically deposited nickel considerably increased the electro-oxidation rate of hypophosphite on copper, gold, and palladium. TEM examinations showed that activation of copper in a PdCl/sub 2//HCl solution resulted in the deposition of palladium in the form of separate patches. Electroless nickel deposition on copper substrates with separate palladium spots took place on copper and palladium independently of each other. The deposition on palladium was faster than that on copper. It was concluded that the activation of copper substrates around palladium spots occurred solely through a spontaneous potential shift, induced by electro-oxidation of hypophosphite on the palladium spots. It was suggested that small amounts of one metal synergistically enhanced the catalytic activity of the other metals.

Flis, J.; Duquette, D.J.

1984-02-01

394

Regulation of gemma formation in the copper moss Scopelophila cataractae by environmental copper concentrations.  

PubMed

Considerable attention has recently been focused on the use of hyperaccumulator plants for the phytoremediation of soils contaminated with heavy metals. The moss, Scopelophila cataractae (Mitt.) Broth., is a typical hyperaccumulator that is usually observed only in copper-rich environments and which accumulates high concentrations of copper in its tissues. However, many of the physiological processes and mechanisms for metal hyperaccumulation in S. cataractae remain unknown. To address this issue, we examined the mechanisms regulating gemma formation, which is considered the main strategy by which S. cataractae relocates to new copper-rich areas. From this study we found that treatment of S. cataractae with high concentrations of copper suppressed gemma formation but promoted protonemal growth. The suppressive effect was not observed by treatment with heavy metals other than copper. These results suggest the importance of copper-sensitive asexual reproduction in the unique life strategy of the copper moss, S. cataractae. PMID:21082328

Nomura, Toshihisa; Hasezawa, Seiichiro

2011-09-01

395

Paramagnetism in copper monoxide systems  

Microsoft Academic Search

This paper describes the problem of high-temperature superconductivity related to investigations of the magnetic susceptibility,\\u000a electron paramagnetic resonance, and O K? x-ray emission spectra of samples from the following systems based on copper monoxide: CuO-Cu, CuO-Cu2O and CuO-MgO. In all these systems, thermal processing results in a paramagnetism which is not observed in the individual\\u000a components of these systems before

A. A. Samokhvalov; T. I. Arbusova; N. A. Viglin; S. V. Naumov; V. R. Galakhov; D. A. Zatsepin; Yu. A. Kotov; O. M. Samatov; D. G. Kleshchev

1998-01-01

396

Reliable laser micro-welding of copper  

Microsoft Academic Search

The reliability of copper welds is still a problem today concerning the high demands of spot or contact welding for the electronic or medical industry. Due to the low absorptivity at wavelengths of 1 micron and the very high thermal conductivity of copper, even small surface contaminations lead to drastic variations in weld quality. The wavelength of 532 nm (frequency-doubled

Christoph Rüttimann; Ulrich Dürr; Anas Moalem; Marc Priehs

2011-01-01

397

Copper uptake by the water hyacinth  

Microsoft Academic Search

Factors affecting Cu uptake by the water hyacinth (Eichornia crassipes) were examined. Two phases of copper uptake were observed throughout the uptake range (1–1000 mg\\/1). An initial rapid uptake phase of 4 hours followed by a slower, near linear uptake phase extending past 48 hours was observed. Stirring the solution enhanced uptake, suggesting copper removal is partially diffusion limited. Variations

Terrence A. Lee; James K. Hardy

1987-01-01

398

Copper metallization of stainless steels. Final report  

SciTech Connect

Stainless steel plates were vacuum metallized with pure copper films 0.004 inch thick. Prior to metallization the surfaces were cleaned with EPA-approved detergents. A thin layer of chromium was sputtered for improved adhesion followed by sputtering of the copper. Results showed excellent adhesion of the sputtered films to the substrates.

Rosenblum, B.Z.

1994-09-01

399

Surface films and corrosion of copper.  

National Technical Information Service (NTIS)

In Sweden and Finland the spent nuclear fuel is planned to be encapsulated in cast iron canisters that have an outer shield made of copper. The copper shield is responsible for the corrosion protection of the canister construction. General corrosion of th...

J. Hilden T. Laitinen K. Maekelae T. Saario M. Bojinov

1999-01-01

400

Copper laser diagnostics and kinetics support  

SciTech Connect

In the effort MSNW participated with the LINL copper-Vapor Laser Program by providing a useful plasma diagnostic for interpretation of Copper-vapor laser kinetics. MSNW developed and delivered a pulsed interferometric diagnostic package to LLNL. Moreover MSNW provided personal services at the request and direction of LLL in the implementation of the diagnostic and interpretation of the data.

Not Available

1981-12-01

401

Corrosion inhibition in copper by isolated bacteria  

Microsoft Academic Search

Purpose – The purpose of this paper is to report a study of microbiological influenced corrosion (MIC) of copper due to bacteria strains isolated from potable water pipes and oxidation lagoons using electrochemical noise (EN) analysis and scanning electron microscopy (SEM). Design\\/methodology\\/approach – Bacteria strains isolated from copper surfaces of potable water pipes and from oxidation lagoons were identified, based

Fernando Garcia; Ana Leonor Rivera Lopez; Juan Campos Guillén; Luis Hernández Sandoval; Carlos Regalado González; Victor Castaño

2012-01-01

402

Treatment of Copper Smelting and Refining Wastes.  

National Technical Information Service (NTIS)

The domestic primary copper industry generates in excess of 600 million metric tons of mining and mineral-processing waste annually. The U.S. Bureau of Mines has researched methods to mitigate the environmental threat posed by copper-processing wastes whi...

D. K. Steele K. S. Gritton S. B. Odekirk

1994-01-01

403

Early copper smelting at Itziparátzico, Mexico  

Microsoft Academic Search

Archaeological fieldwork and archaeometallurgical analysis have identified a Late Postclassic regional centre of copper production in western Mexico. The total output from a single unit of production at the site of Itziparátzico is an estimated ten tons of copper and nearly forty tons of slag over the lifetime of the installation. It is argued that this smelting was based on

Blanca Maldonado; Thilo Rehren

2009-01-01

404

CONTROL OF COPPER SMELTER FUGITIVE EMISSIONS  

EPA Science Inventory

This report deals with fugitive emissions from copper smelting and with related emission control measures. The study involved evaluation of the controls now used in the copper smelting industry and development of suggestions for alternative control devices and practices. A brief ...

405

Plasma copper concentrations in pathological pregnancies.  

PubMed

Copper is an essential element required for the formation of many enzymes with important roles in the human body. During pregnancy, the maternal serum copper concentration is increased due to the higher levels of ceruloplasmin that are the result of elevated oestrogen levels. The aim of this work was to investigate maternal plasma copper concentrations in relation to various pathological conditions during pregnancy. A total of 319 maternal plasma samples were analysed: 103 taken from women in the first trimester, 73 in the second trimester, 99 in the third trimester of pregnancy and 44 at delivery. The plasma concentration of copper during each trimester of normal pregnancy was taken as a reference value. Group comparisons performed by analysis of variance (ANOVA) followed by Dunnett test indicated substantially lower plasma concentrations of copper in pathological conditions diagnosed during the first trimester of pregnancy (spontaneous abortion, threatened abortion, missed abortion and blighted ovum). No significant differences in maternal plasma blood copper concentrations were found in pathological conditions (threatened abortion, threatened preterm delivery and pyelonephritis) diagnosed in the second trimester of pregnancy. Significant differences in plasma copper concentrations were found in the third trimester, for which finding the Dunnett test indicated the cholestasis group to be responsible. Except for twin pregnancy, a tendency to higher plasma copper concentrations, however not statistically significant, was observed in other pathological conditions during the third trimester (gestosis, intrauterine growth retardation, preterm labour). PMID:16325535

Alebic-Juretic, Ana; Frkovic, Aleksandra

2005-01-01

406

Application of INKORAM-75 copper corrosion inhibitor  

NASA Astrophysics Data System (ADS)

Treatment of cooling water with INKORAM-75 copper corrosion inhibitor is applied for reducing corrosion processes in the copper-containing alloy of which turbine condensers are made. The results obtained from industrial trial of the INKORAM-75 inhibitor in the service cooling water system of the Novovoronezh NPP Units 3 and 4 are presented.

Galanin, A. V.; Fedorov, A. I.; Kucherenko, O. V.; Gromov, A. F.

2014-02-01

407

NON-UNIFORM COPPER CORROSION: RESEARCH UPDATE  

EPA Science Inventory

Pinhole leaks due to copper pitting corrosion are a major cause of home plumbing failure. This study documents cases of copper pitting corrosion found in homes supplied by Butler County Environmental Services in Ohio. SEM. XRD, and optical microscopy were used to document pit s...

408

Biosorption of copper by fungal melanin  

Microsoft Academic Search

Melanin obtained from Aureobasidium pullulans and Cladosporium resinae was an efficient biosorbent for copper. Copper uptake could be expressed using various adsorption isotherms; melanin from A. pullulans obeyed Freundlich and Langmuir isotherms whereas C. resinae melanin followed the BET isotherm indicating a more complex type of adsorption than in A. pullulans. In general, uptake capacities of melanin were greater than

Geoffrey M. Gadd; Louise de Rome

1988-01-01

409

Last Metal Copper Metallization for Power Devices  

Microsoft Academic Search

High current-carrying capacity and low resistivity are key parameters for power devices. In this paper a copper based terminal metallurgy scheme for wire- and wedge-bonding is described, which improves these properties. The method of choice for depositing thick copper wires is pattern plating. However the plating process has to be optimized in order to get a homogeneous thickness distribution. An

Werner Robl; Michael Melzl; Berngard Weidgans; Renate Hofmann; Matthias Stecher

2008-01-01

410

Defect analysis of copper ball bonding  

Microsoft Academic Search

Copper ball bonding has gained more and more popularity compared to gold ball bonding due to its better electrical conductivity, better thermal conductivity, higher mechanical strength, lower cost and better reliability and so on. However copper wire has two well-known disadvantages, one is its greater hardness, the other is being easy to be oxidized when forming FAB (free air ball).

Huabin Chu; Jun Hu; Ling Jin; Yingliang Jie

2008-01-01

411

Critical study of thermosonic copper ball bonding  

Microsoft Academic Search

Copper wire is getting well accepted as a reliable design alternative to the gold wire in the wire bonding process. In the present study, the shear strength results of the copper ball bond show better performance than the gold bond. Additionally, microhardness results also confirm that Cu ball bonds reveal a higher hardness of 111 VHN than that of initial

N. Srikanth; S. Murali; Y. M. Wong; Charles J. Vath

2004-01-01

412

POLLUTION ABATEMENT IN A COPPER WIRE MILL  

EPA Science Inventory

This Capsule Report shows how water consumption in copper wire mills can be reduced by 90%. The reduction was from 200,000 gallons per day to 20,000 gallons per day by chemical rinsing and water reuse. The sulfuric acid pickle was regenerated and high purity metallic copper recov...

413

Copper staves in the blast furnace  

Microsoft Academic Search

Operational data for stave cooling systems for two German blast furnaces show good correlation with predicted thermal results. Copper staves have been installed in blast furnaces in the zones exposed to the highest thermal loads. The good operational results achieved confirm the choice of copper staves in the areas of maximum heat load. Both temperature measurements and predictions establish that

R. G. Helenbrook; W. Kowalski; K. H. Grosspietsch; H. Hille

1996-01-01

414

Differential Bacteriophage Mortality on Exposure to Copper ?  

PubMed Central

Many studies report that copper can be used to control microbial growth, including that of viruses. We determined the rates of copper-mediated inactivation for a wide range of bacteriophages. We used two methods to test the effect of copper on bacteriophage survival. One method involved placing small volumes of bacteriophage lysate on copper and stainless steel coupons. Following exposure, metal coupons were rinsed with lysogeny broth, and the resulting fluid was serially diluted and plated on agar with the corresponding bacterial host. The second method involved adding copper sulfate (CuSO4) to bacteriophage lysates to a final concentration of 5 mM. Aliquots were removed from the mixture, serially diluted, and plated with the appropriate bacterial host. Significant mortality was observed among the double-stranded RNA (dsRNA) bacteriophages ?6 and ?8, the single-stranded RNA (ssRNA) bacteriophage PP7, the ssDNA bacteriophage ?X174, and the dsDNA bacteriophage PM2. However, the dsDNA bacteriophages PRD1, T4, and ? were relatively unaffected by copper. Interestingly, lipid-containing bacteriophages were most susceptible to copper toxicity. In addition, in the first experimental method, the pattern of bacteriophage ?6 survival over time showed a plateau in mortality after lysates dried out. This finding suggests that copper's effect on bacteriophage is mediated by the presence of water.

Li, Jinyu; Dennehy, John J.

2011-01-01

415

Compact copper coil ignition tokamak devices  

SciTech Connect

This report discusses the compact copper ignition studies being presently carried out in the USA. Scoping and preconceptual design studies during FY85 and early FY86 have focused on a minimum cost compact copper coil ignition device. The mission of this program is to develop and optimize ignited plasma operation. Secondary objectives include the development of some plasma interactive components. 2 figures.

Schmidt, J.A.

1986-03-01

416

Copper alloy having improved stress relaxation resistance  

US Patent & Trademark Office Database

A copper alloy having improved stress relaxation resistance is formed from a copper base alloy that consists, by weight, essentially of 1.8%-3.0% iron, 0.01%-1.0% zinc, 0.001 %-0.25% phosphorus, 0.1 %-0.35% magnesium and the balance is copper and unavoidable impurities. When compared to other copper base alloys that include iron, zinc and phosphorous, the disclosed alloy has improved resistance to stress relaxation. In addition, directionality of stress relaxation resistance (where stress relaxation resistance is typically poorer in a transverse strip direction relative to a longitudinal strip direction for a copper alloy that is strengthened by cold rolling) is reduced to being nearly equivalent, regardless of strip direction. The alloy is particularly useful for electronic applications, such as being formed into an electrical connectors.

2003-10-14

417

Surface chemistry of nanostructures: 1) interactions of mixed monolayers of carboxylic acids on titania, 2) synthesis and immobilization of aqueous cadmium selenide quantum dots  

NASA Astrophysics Data System (ADS)

This thesis will focus on (1) characterization of mixed monolayers of thiol-terminated (T) and methyl-terminated (Me) carboxylic acids on nanocrystalline TiO2 thin films, (2) the synthesis of aqueous CdSe quantum dots (QDs), with particular emphasis on the influence of capping-group functionality and reaction conditions on the kinetics and mechanism of particle growth, and (3) attachment of CdSe QDs to TiO2 thin films and their photoelectrochemical performance as a function of surfactant in QD-sensitized solar cells (QDSSCs). Mixed monolayers have been used in many applications, such as chemical sensing, biomolecular recognition, molecular electronics, catalysis, and as building blocks for materials assembly. Mixed monolayers of T and Me on TiO 2 underwent dimerization-induced compositional changes. Me was displaced on the surface by T because of the formation of intermolecular disulfide bonds between thiol groups of T adsorbed to the TiO2 surface. The compositional changes were found to vary as a function of solvent, alkyl chain length of T, steric bulk of adsorbates, and surface-binding and terminal functional groups. The findings illustrate that dimerization and other intermolecular interactions between adsorbates may dramatically influence the composition and terminal functionalization of mixed monolayers. Semiconductor QDs are attractive alternatives to molecular chromophores and bulk semiconductors for light-harvesting applications in photovoltaics and photocatalysis. Aqueous QDs are of particular interest due to their straightforward, cost-effective, and environmentally-benign syntheses. CdSe QDs were synthesized in basic aqueous suspensions at room temperature under ambient conditions by mixing a cadmium precursor, selenide precursor, and one of several carboxylate-functionalized capping groups (cysteinate, mercaptopropionate, and mercaptosuccinate). The photophysical properties of the QDs varied with capping-group functionality, concentration of precursors, and pH of the aqueous reaction mixture. Varying these parameters allowed for systematic control of the kinetics and mechanism of particle growth, as well as the size and size distribution of QDs at equilibrium. Under certain conditions, "magic-sized" clusters (MSCs) of CdSe, rather than regular QDs, were preferentially synthesized. The carboxylated capping groups of aqueous QDs were used as bifunctional linkers, allowing for facile attachment to nanocrystalline TiO2 thin films. Equilibrium binding experiments were performed to quantify the adsorption of regular QDs and MSCs to nanocrystalline TiO2 thin films. Finally, photoelectrochemistry was used to quantify the influence of capping-group functionality on the efficiency of electron injection from adsorbed QDs into TiO2 and the power-conversion efficiency of QDSSCs.

Nevins, Jeremy S.

418

High arsenic intake raises kidney copper and lowers plasma copper concentrations in rats.  

PubMed

The effect of high arsenic intake on copper metabolism was investigated. Male rats aged 6 wk had free access to purified diets containing either 0 or 100 mg As/kg diet and demineralized water for a period of 2 wk. Arsenic was added to the diet in the form of NaAsO2. The high-arsenic diet decreased feed and water intake and body weight gain, but significantly increased liver weight. Kidney weight was not affected. Arsenic feeding drastically elevated kidney copper concentration, but significantly reduced copper concentration in plasma. Both true absorption and biliary excretion of copper were decreased significantly in rats fed the high-arsenic diet. True copper absorption was lowered essentially through the lower copper intake in the rats fed arsenic. It is speculated that arsenic feeding primarily leads to copper accumulation in the kidney, followed by a decrease in feed intake and thus in true, absolute copper absorption, a decrease in plasma copper concentration, and a decrease in biliary copper excretion. PMID:11508332

Yu, S; Beynen, A C

2001-07-01

419

Thermal enrichment and speciation of copper in rice husk ashes.  

PubMed

Copper(II) was considerably enriched in the residual ash via thermal treatment of copper-sorbed rice husk at 700-1100°C for 2h, and the copper speciation was quantitatively determined with X-ray absorption spectroscopy. After the thermal process, the resulting ash only represents by weight 18.7-26.4% of the pre-heated samples. Copper content in the ashes is >7% which is far above the required minimum copper content in copper ores for the copper smelting sector, 0.5%. Crystalline SiO(2) is observed only in the ash generated at 1100°C, with more copper in this ash being available for leaching in acidic solution. It is suggested that this is due to the considerable dissimilarity in crystalline structure between copper compounds and crystalline SiO(2). No chemical reaction between copper and SiO(2) is observed in any ash. In fact, we suggest that the SiO(2) crystalline phase repels copper during the thermal process; this would make it easy to extract copper from the ashes. For copper speciation in the ashes, CuO merely represents 0-12% of the total copper, while Cu(2)O and Cu(0) represent 34-42% and 46-63%, respectively. The lower copper oxidation state would be beneficial for the copper smelting process due to less usage of coke. PMID:20869164

Wei, Yu-Ling; Hu, Ming-Jan; Peng, Yen-Hsun

2010-12-15

420

The Intec Copper Process: A Detailed Environmental Analysis  

Microsoft Academic Search

The Intec Copper Process is an environmentally advantageous hydrometallurgical process for the production of high purity copper and associated precious metals from copper sulphide concentrates. The process uses a mixed chloride-bromide lixiviant in an elegant cyclic circuit to leach the copper into solution, rejecting the iron as stable hematite rather than as unstable jarosite. After purification of the pregnant liquor,

D Sammut; N J Welham

421

THE IMPACT OF ORTHOPHOSPHATE ON COPPER CORROSION AND CHLORINE DEMAND  

EPA Science Inventory

In 1991, EPA promulgated the Lead and Copper Rule, which established a copper action level of 1.3 mg/L in a 1-liter, first-draw sample collected from the consumer?s tap. Excessive corrosion of copper can lead to elevated copper levels at the consumer's tap, and in some cases, can...

422

Bioinorganic Chemical Modeling of Dioxygen-Activating Copper Proteins.  

ERIC Educational Resources Information Center

Discusses studies done in modeling the copper centers in the proteins hemocyanin (a dioxygen carrier), tyrosinase, and dopamine beta-hydroxylase. Copper proteins, model approach in copper bioinorganic chemistry, characterization of reversible oxygen carriers and dioxygen-metal complexes, a copper mono-oxygenase model reaction, and other topics are…

Karlin, Kenneth D.; Gultneh, Yilma

1985-01-01

423

Recombination activity of copper in silicon  

NASA Astrophysics Data System (ADS)

The carrier recombination activity of copper in n-type and p-type silicon has been investigated. The minority carrier diffusion length has been found to decrease monotonically with increasing copper concentration in n Si and to exhibit a step-like behavior in p-type silicon at Cu concentrations above a certain critical level. It is suggested that the impact of copper on the minority carrier diffusion length is determined by the formation of copper precipitates. This process is retarded in perfect silicon due to the large lattice mismatch between Cu3Si and the silicon lattice and even more retarded in p Si, due to electrostatic repulsion effects between the positively charged copper precipitates and interstitial copper ions. Comparison of the impact of Cu on minority carrier diffusion length obtained with p-Si samples of different resistivity confirmed the electrostatic model. Studies of the impact of copper on minority carrier diffusion length in samples with internal gettering sites indicated that they provide heterogeneous nucleation sites for Cu precipitation at subcritical Cu concentration. Above a certain threshold of Cu concentration, the bulk recombination activity is dominated by quasihomogeneous formation of Cu precipitates, a process that is not detectably affected by the presence of oxide precipitates.

Sachdeva, R.; Istratov, A. A.; Weber, E. R.

2001-10-01

424

Electrochromism in copper oxide thin films  

SciTech Connect

Transparent thin films of copper(I) oxide prepared on conductive SnO2:F glass substrates by anodic oxidation of sputtered copper films or by direct electrodeposition of Cu2O transformed reversibly to opaque metallic copper films when reduced in alkaline electrolyte. In addition, the same Cu2O films transform reversibly to black copper(II) oxide when cycled at more anodic potentials. Copper oxide-to-copper switching covered a large dynamic range, from 85% and 10% photopic transmittance, with a coloration efficiency of about 32 cm2/C. Gradual deterioration of the switching range occurred over 20 to 100 cycles. This is tentatively ascribed to coarsening of the film and contact degradation caused by the 65% volume change on conversion of Cu to Cu2O. Switching between the two copper oxides (which have similar volumes) was more stable and more efficient (CE = 60 cm2/C), but covered a smaller transmittance range (60% to 44% T). Due to their large electrochemical storage capacity and tolerance for alkaline electrolytes, these cathodically coloring films may be useful as counter electrodes for anodically coloring electrode films such as nickel oxide or metal hydrides.

Richardson, T.J.; Slack, J.L.; Rubin, M.D.

2000-08-15

425

Seminar on Copper and Copper Alloy Forged and Pressed Components: Proceedings of the Seminar Held in Pune, December 1-2, 1977.  

National Technical Information Service (NTIS)

Various papers presented at the seminar covered the following topics: Application of Forged and Pressed Copper and Copper Alloy Components; Copper Base Alloy Forgings for High Pressure Applications; Materials for Forged and Pressed Components; Copper and ...

1977-01-01

426

Incorporation of copper into lysyl oxidase.  

PubMed Central

Lysyl oxidase is a copper-dependent enzyme involved in extracellular processing of collagens and elastin. Although it is known that copper is essential for the functional activity of the enzyme, there is little information on the incorporation of copper. In the present study we examined the insertion of copper into lysyl oxidase using 67Cu in cell-free transcription/translation assays and in normal skin fibroblast culture systems. When a full-length lysyl oxidase cDNA was used as a template for transcription/translation reactions in vitro, unprocessed prolysyl oxidase appeared to bind copper. To examine further the post-translational incorporation of copper into lysyl oxidase, confluent skin fibroblasts were incubated with inhibitors of protein synthesis (cycloheximide, 10 microg/ml), glycosylation (tunicamycin, 10 microg/ml), protein secretion (brefeldin A, 10 microg/ml) and prolysyl oxidase processing (procollagen C-peptidase inhibitor, 2.5 microg/ml) together with 300 microCi of carrier-free 67Cu. It was observed that protein synthesis was a prerequisite for copper incorporation, but inhibition of glycosylation by tunicamycin did not affect the secretion of 67Cu as lysyl oxidase. Brefeldin A inhibited the secretion of 67Ci-labelled lysyl oxidase by 46%, but the intracellular incorporation of copper into lysyl oxidase was not affected. In addition, the inhibition of the extracellular proteolytic processing of prolysyl oxidase to lysyl oxidase had minimal effects on the secretion of protein-bound 67Cu. Our results indicate that, similar to caeruloplasmin processing [Sato and Gitlin (1991) J. Biol. Chem. 266, 5128-5134], copper is inserted into prolysyl oxidase independently of glycosylation.

Kosonen, T; Uriu-Hare, J Y; Clegg, M S; Keen, C L; Rucker, R B

1997-01-01

427

Isolation of copper-binding proteins from activated sludge culture.  

PubMed

Six copper-binding microbial proteins were isolated from activated sludge cultures grown on media containing copper at various concentrations. Molecular weights among isolated proteins were ranged from 1.3k to 1 74k dalton. Isolated proteins were compared for their copper binding capabilities. Proteins isolated from cultures grown in the presence of copper in the growth media exhibited higher copper binding capabilities than those isolated from the culture grown in the absence of copper. The highest metal uptake of 61.23 (mol copper/mol protein) was observed by a protein isolated from a culture grown with copper at a concentration of 0.25 mM. This isolated protein (CBP2) had a molecular weight of 24k dalton. Other protein exhibited copper binding capability of 4.8-32.5 (mol copper/mol protein). PMID:11548018

Fukushi, K; Kato, S; Antsuki, T; Omura, T

2001-01-01

428

Pool Boiling Performance Comparison of Smooth and Sintered Copper Surfaces with and Without Carbon Nanotubes  

Microsoft Academic Search

Pool boiling heat transfer is measured with two individual working fluids on copper surfaces enhanced with sintered copper powder and carbon nanotubes. The working fluids are a segregated hydrofluoroether, HFE-7300 (3M Electronic Markets Materials Division, St. Paul, MN), and deionized water. The surfaces considered in the experiments include smooth copper, copper with sintered copper particles, smooth copper with copper-coated carbon

John P. McHale; Suresh V. Garimella; Timothy S. Fisher; Glen A. Powell

2011-01-01

429

Investigation on the production of copper nitride (copper azide) thin films and their nanostructures  

NASA Astrophysics Data System (ADS)

Copper thin films of 80-nm thickness were deposited on glass substrate using electron beam deposition at two different deposition angles of 0° and 40°, and they were post-annealed under flow of nitrogen at different temperatures. The structure of the films was analyzed using X-ray diffraction, atomic force microscope, and scanning electron microscope. Investigation on the copper nitride phase formation showed that this phase was not formed in the samples produced at 0°, while those prepared at oblique angle of 40° clearly showed the formation of copper azide phase. This is related to the porosity of the film structure, hence increased surface area for the reaction of nitrogen with copper atoms. Therefore, this is a simple method for preparation of copper nitride films that are not usually formed due to low reactivity of copper (as transition metal) with nitrogen. The results showed that the crystallite size (coherently diffracting domains), grain size, and surface roughness increase with annealing temperature.

Lotfi-Kaljahi, Amir; Savaloni, Hadi

2013-01-01

430

Thermodynamic study of solid copper nickel alloys by use of copper beta-alumina  

NASA Astrophysics Data System (ADS)

Copper ??-alumina was prepared by ion exchange reactions starting with a sodium ??-alumina. Exchange from sodium ion to copper ion was done by immersing the sample in liquid cuprous chloride. Exchange of Na+ ion in ??-alumina to Cu+ ion was not complete as Na+ ion remained within the ??-alumina. Copper activity in solid copper nickel alloys was measured by electromotive force (EMF) technique incorporating the partially exchanged (Cu+ Na+) ??-alumina as a solid electrolyte for temperatures between 870 and 1300 K. The activities of copper and nickel in the solid solution at these temperatures exhibited positive deviations from Raoult's law. The activity coefficients of copper and nickel at infinite dilution at 973 K were estimated to be 5.55 and 3.71, respectively. Furthermore, the free energies, enthalpies and entropies of mixing were derived from EMF data.

Oishi, Toshio; Tagawa, Shinya; Tanegashima, Soichiro

2005-02-01

431

Myeloneuropathy due to copper deficiency: clinical and MRI findings after copper supplementation.  

PubMed

Acquired copper deficiency constitutes an under-recognised cause of myelopathy. Aim of the study was to describe the clinical and imaging features at admission and after copper supplementation of a patient with acquired copper deficiency myeloneuropathy. A 73-year-old woman presented with anaemia and signs of posterior column dysfunction. Somatosensory evoked potentials showed impaired central pathway conduction. Serum copper and caeruloplasmin levels were low. Nerve conduction assessment revealed axonal polyneuropathy. Spinal magnetic resonance imaging (MRI) showed posterior column hyperintensity. Diffusion tensor imaging disclosed decreased fractional anisotropy (FA) corresponding to the hyperintensity. Copper supplementation normalised the haematological picture, whereas vibratory sensitivity was only slightly improved. Control MRI revealed a slight hyperintensity at C1-C2 level; FA values normalised. In conclusion, in acquired copper-deficiency-associated myelopathy, correction of blood and MRI alterations precedes that of neurological manifestations, which may remain suboptimal. PMID:19768378

Bolamperti, Laura; Leone, Maurizio A; Stecco, Alessandro; Reggiani, Monica; Pirisi, Mario; Carriero, Alessandro; Monaco, Francesco

2009-12-01

432

In situ deposits of copper and copper oxide containing condensation polyimide films  

NASA Technical Reports Server (NTRS)

Novel copper-polyimide composites have been synthesized via simultaneous thermal decomposition of solid solutions of bis (trifluoroacetylacetonato) copper (II) and thermal cyclodehydration of polyimide acid. In contrast to conventional filled polymer composites which are prepared by dispersion of particles or fibers in a polymer matrix this study has yielded in general uniform Cu or CuO dispersions of very small particle size that reside near the film surface that was exposed to the atmosphere during curing. The nature of the copper deposit, the thickness of the copper deposit, and the polyimide overlayer which bonds the copper to the polymer substrate depend on the curing atmosphere used. A variety of analytical surface methods along with thermogravimetric analysis and variable temperature (surface and volume) electrical resistivity measurements have been used to characterize these thin, flexible copper doped polyimide films.

Porta, G. M.; Taylor, L. T.

1987-01-01

433

Copper-Exchanged Zeolite L Traps Oxygen  

NASA Technical Reports Server (NTRS)

Brief series of simple chemical treatments found to enhance ability of zeolite to remove oxygen from mixture of gases. Thermally stable up to 700 degrees C and has high specific surface area which provides high capacity for adsorption of gases. To increase ability to adsorb oxygen selectively, copper added by ion exchange, and copper-exchanged zeolite reduced with hydrogen. As result, copper dispersed atomically on inner surfaces of zeolite, making it highly reactive to oxygen, even at room temperature. Reactivity to oxygen even greater at higher temperatures.

Sharma, Pramod K.; Seshan, Panchalam K.

1991-01-01

434

Shock induced spall fracture in polycrystalline copper  

NASA Astrophysics Data System (ADS)

The plate impact experiments have been conducted on commercially available 99.99% pure polycrystalline samples of copper using single stage gas gun facility. The free surface velocity history of the sample plate measured using VISAR instrument is utilized to determine the dynamic yield strength and spall strength of copper. The dynamic yield strength and spall strength of polycrystalline copper sample has been determined to be 0.14 GPa and 1.32 GPa, respectively with corresponding strain rates of the order of 104/s.

Mukherjee, D.; Rav, Amit; Sur, Amit; Joshi, K. D.; Gupta, Satish C.

2014-04-01

435

Electromigration threshold in copper interconnects  

SciTech Connect

The electromigration threshold in copper interconnects is reported in this study. The length-dependent electromigration degradation rate is observed and quantified in the temperature range of 295{endash}400{degree}C. Based on the Blech electromigration model [I. A. Blech, J. Appl. Phys. >47, 1203 (1976)], a simplified equation is proposed to analyze the experimental data from various combinations of current density and interconnect length, as well as to estimate the electromigration threshold product of current density and line length, (jL){sub th}, at a certain temperature. The resulting (jL){sub th} value appears to be temperature dependent, decreasing with increasing temperature in the tested range between 295 and 400{degree}C. {copyright} 2001 American Institute of Physics.

Wang, P.-C.; Filippi, R. G.

2001-06-04

436

Metallochaperones regulate intracellular copper levels.  

PubMed

Copper (Cu) is an important enzyme co-factor that is also extremely toxic at high intracellular concentrations, making active efflux mechanisms essential for preventing Cu accumulation. Here, we have investigated the mechanistic role of metallochaperones in regulating Cu efflux. We have constructed a computational model of Cu trafficking and efflux based on systems analysis of the Cu stress response of Halobacterium salinarum. We have validated several model predictions via assays of transcriptional dynamics and intracellular Cu levels, discovering a completely novel function for metallochaperones. We demonstrate that in addition to trafficking Cu ions, metallochaperones also function as buffers to modulate the transcriptional responsiveness and efficacy of Cu efflux. This buffering function of metallochaperones ultimately sets the upper limit for intracellular Cu levels and provides a mechanistic explanation for previously observed Cu metallochaperone mutation phenotypes. PMID:23349626

Pang, W Lee; Kaur, Amardeep; Ratushny, Alexander V; Cvetkovic, Aleksandar; Kumar, Sunil; Pan, Min; Arkin, Adam P; Aitchison, John D; Adams, Michael W W; Baliga, Nitin S

2013-01-01

437

Metallochaperones Regulate Intracellular Copper Levels  

PubMed Central

Copper (Cu) is an important enzyme co-factor that is also extremely toxic at high intracellular concentrations, making active efflux mechanisms essential for preventing Cu accumulation. Here, we have investigated the mechanistic role of metallochaperones in regulating Cu efflux. We have constructed a computational model of Cu trafficking and efflux based on systems analysis of the Cu stress response of Halobacterium salinarum. We have validated several model predictions via assays of transcriptional dynamics and intracellular Cu levels, discovering a completely novel function for metallochaperones. We demonstrate that in addition to trafficking Cu ions, metallochaperones also function as buffers to modulate the transcriptional responsiveness and efficacy of Cu efflux. This buffering function of metallochaperones ultimately sets the upper limit for intracellular Cu levels and provides a mechanistic explanation for previously observed Cu metallochaperone mutation phenotypes.

Pang, W. Lee; Kaur, Amardeep; Ratushny, Alexander V.; Cvetkovic, Aleksandar; Kumar, Sunil; Pan, Min; Arkin, Adam P.; Aitchison, John D.; Adams, Michael W. W.; Baliga, Nitin S.

2013-01-01

438

Penta-zirconium copper tribismuth.  

PubMed

Penta-zirconium copper tribismuth, Zr5CuBi3, crystallizes in the hexa-gonal Hf5CuSn3 structure type. The asymmetric unit contains two Zr sites (site symmetries 3.2 and m2m), one Cu site (site symmetry 3.m) and one Bi site (site symmetry m2m). The environment of the Bi atoms is a tetra-gonal anti-prism with one added atom and a coordination number (CN) of 9. The polyhedron around the Zr1 atom is a defective cubo-octa-hedron with CN = 11. The bicapped hexa-gonal anti-prism (CN = 14) is typical for Zr2 atoms. The Cu atom is enclosed in a eight-vertex polyhedron (octa-hedron with two centered faces). The metallic type of bonding was indicated by an analysis of the inter-atomic distances and electronic structure calculation data. PMID:24109256

Balinska, Agnieszka; Tarasiuk, Ivan; Pavlyuk, Volodymyr

2013-01-01

439

Penta-zirconium copper tribismuth  

PubMed Central

Penta­zirconium copper tribismuth, Zr5CuBi3, crystallizes in the hexa­gonal Hf5CuSn3 structure type. The asymmetric unit contains two Zr sites (site symmetries 3.2 and m2m), one Cu site (site symmetry 3.m) and one Bi site (site symmetry m2m). The environment of the Bi atoms is a tetra­gonal anti­prism with one added atom and a coordination number (CN) of 9. The polyhedron around the Zr1 atom is a defective cubo­octa­hedron with CN = 11. The bicapped hexa­gonal anti­prism (CN = 14) is typical for Zr2 atoms. The Cu atom is enclosed in a eight-vertex polyhedron (octa­hedron with two centered faces). The metallic type of bonding was indicated by an analysis of the inter­atomic distances and electronic structure calculation data.

Balinska, Agnieszka; Tarasiuk, Ivan; Pavlyuk, Volodymyr

2013-01-01

440

Diethyldithiocarbamate, copper and neurological disorders  

SciTech Connect

Diethyldithiocarbamate (DEDTC) given orally to rats without any addition of copper considerably increased the concentration of Cu in the brain without any change in the other tested tissues. Cysteine, comparatively studied, did not induce any change in the brain Cu level. Based on these findings and the literature data concerning DEDTC effects in animal and human, we put forward the hypothesis that the main effect of DEDTC is to provoke in the brain not a deficiency but an excess of Cu liberated from the lipophilic complex Cu-DEDTC. Cu is then engaged in an oscillatory oxido reduction giving a Cu{sup ++} cation radical able to induce deleterious effects on tissues in a similar way as paraquat. The practical consequences of this hypothesis are considered.

Allain, P.; Krari, N. (Centre Hospitalier Universitaire, Angers (France))

1991-01-01

441

Three stages of copper accumulation in hepatocellular lysosomes: X-ray microanalysis of copper-loaded golden hamsters.  

PubMed Central

Male golden hamsters were loaded with copper by supplying them for up to 12 weeks with drinking water containing 0.5% cupric acetate. The copper feeding increased hepatic copper to widely varying levels. Energy dispersive X-ray microanalysis could always identify a copper-sulphur complex in the hepatocyte lysosomes of copper-loaded hamsters and the X-ray intensity of copper was found to be a reliable parameter to measure in-situ copper accumulation. Combining this parameter with the copper binding ratio expressed by delta Cu/delta S enabled us to discern two stages of sub-histochemical copper accumulation. The first stage was marked by low levels of both lysosomal copper and binding ratio, which suggested that this initial copper transfer was mediated by unsaturated cuproproteins. The second stage was characterized by median amounts of lysosomal copper and a binding ratio of more than 0.50. At the third stage, histochemically detectable copper appeared in animals whose lysosomal copper was extraordinarily high in later experimental periods. With the copper binding ratio being in the same range of 0.50-0.83, it seemed that saturated cuproproteins were the main mediator of copper transport in the later two stages. Images Fig. 2

Yagi, A.; Hayashi, H.; Higuchi, T.; Hishida, N.; Sakamoto, N.

1992-01-01

442

Response of tolerant and wild type strains of Chlorella vulgaris to copper with special references to copper uptake system  

Microsoft Academic Search

Summary Copper tolerance in Chlorella vulgaris has been studied by comparing physiological properties and copper uptake in a wild type strain and a copper tolerant one. A concentrationdependent reduction in growth rate, dry mass, and content of chlorophyll a, protein, sugars and amino acids was noticed in both strains at 1.0 and 400 !g l ?1 copper. The reduction in

A. A. Fathi; F. T. Zaki; H. A. Ibraheim

2005-01-01

443

Mass-spectrometric multielement analysis of copper and copper-base alloys, with electrical detection.  

PubMed

Relative sensitivity coefficients have been determined for 21 elements in copper and its alloys, with iron as an internal standard, by spark-source mass-spectrometry with electrical detection and magnetic peak-switching. Twenty calibration standards ranging from pure copper to 60%-copper alloys were used. The sensitivity coefficients measured appear to be independent of the elemental concentration and are obtained with a mean precision of 15%. PMID:18962160

Van Hoye, E; Gijbels, R; Adams, F

1977-10-01

444

Serum Copper, Ceruloplasmin and 24-h Urine Copper Evaluations in Celiac Patients  

Microsoft Academic Search

The aim of the study is to evaluate the serum copper, ceruloplasmin and 24-h urine copper levels in celiac patients.Serum\\u000a copper, ceruloplasmin and 24-h urine measurements were evaluated in patients with celiac (n = 32), Crohn’s (n = 25), Wilson’s (n = 11) and in a healthy group (n = 35). Serum and 24-h urine zinc levels, AST, ALT, BUN,

Ali Tüzün Ince; Hüseyin Kayadibi; Aliye Soylu; Oya Ovunç; Mustafa Gültepe; Ahmet Burak Toros; Bülent Ya?ar; Tulin Kendir; Evren Abut

2008-01-01

445

Kinetics of iron–copper sulphides oxidation in relation to protohistoric copper smelting  

Microsoft Academic Search

This article deals with one specific step of the copper extractive metallurgy process: the roasting of iron–copper sulphides.\\u000a It aims at shedding light on an archaeological issue: the reconstruction of the copper extractive metallurgy processes during\\u000a protohistory (IVe–IIe millennium BC). Experimental simulations are performed at laboratory scale by modelizing the conditions of protohistoric\\u000a furnaces. Kinetic of roasting is studied by

Emilien BurgerDavid Bourgarit; David Bourgarit; Vincent Frotté; Fabien Pilon

2011-01-01

446

Selective electroless copper plating on silicon seeded by copper ion implantation  

Microsoft Academic Search

We report on the successful use of copper (self) ion implantation into silicon to seed the electroless plating of copper on silicon (100) surfaces. Copper ions were implanted into silicon to doses of 5 times 10(exp 14)-6.4 times 10(exp 16) ions\\\\sq cm using a metal vapour vacuum arc ion implanter at extraction voltages of 10 kV and 20 kV. A

S. Bhansali; D. K. Sood; R. B. Zmood

1994-01-01

447

Nanocrystalline copper doped zinc oxide produced from copper doped zinc hydroxide nitrate as a layered precursor  

Microsoft Academic Search

Undoped and copper doped nanostructured zinc oxides were synthesized by using a series of synthetic layered material, undoped and copper doped zinc hydroxide nitrates at various molar percentages of copper (2–10) within the layers as precursors. The layered materials were heat-treated at 500°C to produce zinc oxide nanostructures with crystallite sizes in the range of 23–35nm. Optical studies of the

Mohammad Yeganeh Ghotbi; Narjes Bagheri; S. K. Sadrnezhaad

448

Impurity control and removal in copper tankhouse operations  

Microsoft Academic Search

During copper smelting, most of the undesirable impurities such as Pb, Sb, Bi, and As are only partially removed by oxidation.\\u000a When white metal and blister copper are in equilibrium, these impurities are distributed mainly into the copper phase, from\\u000a which their removal is difficult. When copper dissolves during electrorefining in a copper tankhouse, these impurities are\\u000a continuously released from

Shijie Wang

2004-01-01

449

Managing the Use of Copper-Based Antifouling Paints  

Microsoft Academic Search

Copper is the biocide of choice for present-day antifouling (AF) paints. It is also a major source of copper loading in to\\u000a the marine environment and, as such, might cause local copper levels to exceed water quality criteria. The present study is\\u000a multifaceted and looks into the overall impact of copper-based AF paints on copper concentrations along a 64-km stretch

Mridula Srinivasan; Geoffrey W. Swain

2007-01-01

450

A novel copper site in a cyanobacterial metallochaperone.  

PubMed Central

The thylakoid lumen of the cyanobacterium Synechocystis PCC 6803 is supplied with copper via two copper-transporting ATPases and a metallochaperone intermediary. We show that the copper site of this metallochaperone is unusual and consists of two cysteine residues and a histidine imidazole located on structurally dynamic loops. Substitution of this histidine residue enhances bacterial two-hybrid interaction with the cytosolic copper exporter, but not the copper importer, suggesting that the interacting surfaces are distinct, with implications for metal transfer.

Borrelly, Gilles P M; Blindauer, Claudia A; Schmid, Ralf; Butler, Clive S; Cooper, Chris E; Harvey, Ian; Sadler, Peter J; Robinson, Nigel J

2004-01-01

451

Electroless deposition of copper and fabrication of copper micropatterns on CVD diamond film surfaces  

NASA Astrophysics Data System (ADS)

Electroless deposition of copper on as-grown and amino-modification diamond substrates was investigated. The compact and uniform copper films were successfully electrolessly deposited on as-grown and amino-modification diamond substrates after activation by Pd/Sn colloid nanoparticles. The adhesion interaction between copper films and diamond substrates was roughly estimated by the ultrasonic treatment. The results showed the higher adhesion interaction between copper films and amino-modification diamond substrates than that between the copper films and as-grown diamond substrates due to the greater attractive force between the Pd/Sn colloid nanoparticles and amino-modified diamond surface. The favorable copper micropatterns were successfully constructed on diamond film surfaces by means of the catalyst lift-off method and the copper lift-off method. Furthermore, the electrochemical behavior of copper-modified boron-doped diamond (BDD) was studied for glucose oxidation in 0.2 M sodium hydroxide solution by using cyclic voltammetry, and the result indicated that copper-modified BDD exhibited high catalytic activity to electrochemical oxidation of glucose in alkaline media.

Zhao, Jianwen; Tian, Ruhai; Zhi, Jinfang

2008-03-01

452

Expression of prion protein increases cellular copper binding and antioxidant enzyme activities but not copper delivery.  

PubMed

The N-terminal region of the prion protein PrP(C) contains a series of octapeptide repeats. This region has been implicated in the binding of divalent metal ions, particularly copper. PrP(C) has been suggested to be involved in copper transport and metabolism and in cell defense mechanisms against oxidative insult, possibly through the regulation of the intracellular CuZn superoxide dismutase activity (CuZn-SOD) or a SOD-like activity of PrP(C) itself. However, up to now the link between PrP(C) expression and copper metabolism or SOD activity has still to be formally established; particularly because conflicting results have been obtained in vivo. In this study, we report a link between PrP(C), copper binding, and resistance to oxidative stress. Radioactive copper ((64)Cu) was used at a physiological concentration to demonstrate that binding of copper to the outer plasma cell membrane is related to the level of PrP(C) expression in a cell line expressing a doxycycline-inducible murine PrP(C) gene. Cellular PIPLC pretreatment indicated that PrP(C) was not involved in copper delivery at physiological concentrations. We also demonstrated that murine PrP(C) expression increases several antioxidant enzyme activities and glutathione levels. Prion protein may be a stress sensor sensitive to copper and able to initiate, following copper binding, a signal transduction process acting on the antioxidant systems to improve cell defenses. PMID:12500977