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1

Copper-indium-selenide quantum dot-sensitized solar cells.  

PubMed

We present a new synthetic process of near infrared (NIR)-absorbing copper-indium-selenide (CISe) quantum dots (QDs) and their applications to efficient and completely heavy-metal-free QD-sensitized solar cells (QDSCs). Lewis acid-base reaction of metal iodides and selenocarbamate enabled us to produce chalcopyrite-structured CISe QDs with controlled sizes and compositions. Furthermore, gram-scale production of CISe QDs was achieved with a high reaction yield of ~73%, which is important for the commercialization of low-cost photovoltaic (PV) devices. By changing the size and composition, electronic band alignment of CISe QDs could be finely tuned to optimize the energetics of the effective light absorption and injection of electrons into the TiO2 conduction band (CB). These energy-band-engineered QDs were applied to QDSCs, and the quantum-confinement effect on the PV performances was clearly demonstrated. Our best cell yielded a conversion efficiency of 4.30% under AM1.5G one sun illumination, which is comparable to the performance of the best solar cells based on toxic lead chalcogenide or cadmium chalcogenide QDs. PMID:24177572

Yang, Jiwoong; Kim, Jae-Yup; Yu, Jung Ho; Ahn, Tae-Young; Lee, Hyunjae; Choi, Tae-Seok; Kim, Young-Woon; Joo, Jin; Ko, Min Jae; Hyeon, Taeghwan

2013-12-21

2

Characterization of single phase copper selenide nanoparticles and their growth mechanism  

NASA Astrophysics Data System (ADS)

The high quality Cu3Se2 phase of copper selenide nanoparticles was synthesized through the solution-phase chemical reaction between copper and selenium. In this synthesis process, hydrazine hydrate acts as reducing agent whereas ethylene glycol controls the nucleation and growth of particles. An effort has been made to explain the growth mechanism to form copper selenide nanoparticles through the coordination of selenium to the Cu2+ complexes with OH groups of ethylene glycol. Result indicates the formation of Cu3Se2 single phase nanoparticles. The particles with the average particle size 25 nm are spherical in shape having tetragonal structure. The particles are well crystallized having 94% degree of crystallinity. An effort has also been made to determine the energy band gap of copper selenide nanoparticles through the absorption spectra.

Patidar, D.; Saxena, N. S.

2012-03-01

3

Photoconductivity in reactively evaporated copper indium selenide thin films  

NASA Astrophysics Data System (ADS)

Copper indium selenide thin films of composition CuInSe2 with thickness of the order of 130 nm are deposited on glass substrate at a temperature of 423 ±5 K and pressure of 10-5 mbar using reactive evaporation, a variant of Gunther's three temperature method with high purity Copper (99.999%), Indium (99.999%) and Selenium (99.99%) as the elemental starting materials. X-ray diffraction (XRD) studies shows that the films are polycrystalline in nature having preferred orientation of grains along the (112) plane. The structural type of the film is found to be tetragonal with particle size of the order of 32 nm. The structural parameters such as lattice constant, particle size, dislocation density, number of crystallites per unit area and strain in the film are also evaluated. The surface morphology of CuInSe2 films are studied using 2D and 3D atomic force microscopy to estimate the grain size and surface roughness respectively. Analysis of the absorption spectrum of the film recorded using UV-Vis-NIR Spectrophotometer in the wavelength range from 2500 nm to cutoff revealed that the film possess a direct allowed transition with a band gap of 1.05 eV and a high value of absorption coefficient (?) of 106 cm-1 at 570 nm. Photoconductivity at room temperature is measured after illuminating the film with an FSH lamp (82 V, 300 W). Optical absorption studies in conjunction with the good photoconductivity of the prepared p-type CuInSe2 thin films indicate its suitability in photovoltaic applications.

Urmila, K. S.; Asokan, T. Namitha; Pradeep, B.; Jacob, Rajani; Philip, Rachel Reena

2014-01-01

4

A study of the oxidative dissolution of synthetic copper-silver selenide minerals using the Intermittent galvanostatic polarisation (IGP) technique  

Microsoft Academic Search

Intermittent galvanostatic polarisation, combined with solid state analytical techniques and atomic absorption analysis, has been employed to investigate the electrochemical dissolution of synthetic silver selenide (naumannite) and copper-silver selenide (eucairite) in dilute nitric acid and perchloric acid media. At potentials above 0.75 V vs. SCE, silver selenide is oxidised directly to elemental selenium via the reaction: Ag2Se(c) = 2Ag+(aq) +

R. Luo; N. M. Rice; N. Taylor; R. Gee

1997-01-01

5

Chemical synthesis of p-type nanocrystalline copper selenide thin films for heterojunction solar cells  

NASA Astrophysics Data System (ADS)

Nanocrystalline thin films of copper selenide have been grown on glass and tin doped-indium oxide substrates using chemical method. At ambient temperature, golden films have been synthesized and annealed at 200 °C for 1 h and were examined for their structural, surface morphological and optical properties by means of X-ray diffraction (XRD), scanning electron microscopy and UV-vis spectrophotometry techniques, respectively. Cu 2- xSe phase was confirmed by XRD pattern and spherical grains of 30 ± 4 - 40 ± 4 nm in size aggregated over about 130 ± 10 nm islands were seen by SEM images. Effect of annealing on crystallinity improvement, band edge shift and photoelectrochemical performance (under 80 mW/cm 2 light intensity and in lithium iodide electrolyte) has been studied and reported. Observed p-type electrical conductivity in copper selenide thin films make it a suitable candidate for heterojunction solar cells.

Ambade, Swapnil B.; Mane, R. S.; Kale, S. S.; Sonawane, S. H.; Shaikh, Arif V.; Han, Sung-Hwan

2006-12-01

6

Methods of making copper selenium precursor compositions with a targeted copper selenide content and precursor compositions and thin films resulting therefrom  

DOEpatents

Precursor compositions containing copper and selenium suitable for deposition on a substrate to form thin films suitable for semi-conductor applications. Methods of forming the precursor compositions using primary amine solvents and methods of forming the thin films wherein the selection of temperature and duration of heating controls the formation of a targeted species of copper selenide.

Curtis, Calvin J. (Lakewood, CO); Miedaner, Alexander (Boulder, CO); van Hest, Marinus Franciscus Antonius Maria (Lakewood, CO); Ginley, David S. (Evergreen, CO); Leisch, Jennifer (Denver, CO); Taylor, Matthew (West Simsbury, CT); Stanbery, Billy J. (Austin, TX)

2011-09-20

7

Colloidally stable selenium@copper selenide core@shell nanoparticles as selenium source for manufacturing of copper-indium-selenide solar cells.  

PubMed

Selenium nanoparticles with diameters of 100-400nm are prepared via hydrazine-driven reduction of selenious acid. The as-prepared amorphous, red selenium (a-Se) particles were neither a stable phase nor were they colloidally stable. Due to phase transition to crystalline (trigonal), grey selenium (t-Se) at or even below room temperature, the particles merged rapidly and recrystallized as micronsized crystal needles. As a consequence, such Se particles were not suited for layer deposition and as a precursor to manufacture thin-film CIS (copper indium selenide/CuInSe2) solar cells. To overcome this restriction, Se@CuSe core@shell particles are presented here. For these Se@CuSe core@shell nanoparticles, the phase transition a-Se?t-Se is shifted to temperatures higher than 100°C. Moreover, a spherical shape of the particles is retained even after phase transition. Composition and structure of the Se@CuSe core@shell nanostructure are evidenced by electron microscopy (SEM/STEM), DLS, XRD, FT-IR and line-scan EDXS. As a conceptual study, the newly formed Se@CuSe core@shell nanostructures with CuSe acting as a protecting layer to increase the phase-transition temperature and to improve the colloidal stability were used as a selenium precursor for manufacturing of thin-film CIS solar cells and already lead to conversion efficiencies up to 3%. PMID:24267336

Dong, Hailong; Quintilla, Aina; Cemernjak, Marco; Popescu, Radian; Gerthsen, Dagmar; Ahlswede, Erik; Feldmann, Claus

2014-02-01

8

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

9

Highly Luminescent, Size- and Shape-Tunable Copper Indium Selenide Based Colloidal Nanocrystals  

PubMed Central

We report a simple, high-yield colloidal synthesis of copper indium selenide nanocrystals (CISe NCs) based on a silylamide-promoted approach. The silylamide anions increase the nucleation rate, which results in small-sized NCs exhibiting high luminescence and constant NC stoichiometry and crystal structure regardless of the NC size and shape. In particular, by systematically varying synthesis time and temperature, we show that the size of the CISe NCs can be precisely controlled to be between 2.7 and 7.9 nm with size distributions down to 9–10%. By introducing a specific concentration of silylamide-anions in the reaction mixture, the shape of CISe NCs can be preselected to be either spherical or tetrahedral. Optical properties of these CISe NCs span from the visible to near-infrared region with peak luminescence wavelengths of 700 to 1200 nm. The luminescence efficiency improves from 10 to 15% to record values of 50–60% by overcoating as-prepared CISe NCs with ZnSe or ZnS shells, highlighting their potential for applications such as biolabeling and solid state lighting. PMID:24748721

2013-01-01

10

Thin-film copper indium gallium selenide solar cell based on low-temperature all-printing process.  

PubMed

In the solar cell field, development of simple, low-cost, and low-temperature fabrication processes has become an important trend for energy-saving and environmental issues. Copper indium gallium selenide (CIGS) solar cells have attracted much attention due to the high absorption coefficient, tunable band gap energy, and high efficiency. However, vacuum and high-temperature processing in fabrication of solar cells have limited the applications. There is a strong need to develop simple and scalable methods. In this work, a CIGS solar cell based on all printing steps and low-temperature annealing is developed. CIGS absorber thin film is deposited by using dodecylamine-stabilized CIGS nanoparticle ink followed by printing buffer layer. Silver nanowire (AgNW) ink and sol-gel-derived ZnO precursor solution are used to prepare a highly conductive window layer ZnO/[AgNW/ZnO] electrode with a printing method that achieves 16 ?/sq sheet resistance and 94% transparency. A CIGS solar cell based on all printing processes exhibits efficiency of 1.6% with open circuit voltage of 0.48 V, short circuit current density of 9.7 mA/cm(2), and fill factor of 0.34 for 200 nm thick CIGS film, fabricated under ambient conditions and annealed at 250 °C. PMID:25180569

Singh, Manjeet; Jiu, Jinting; Sugahara, Tohru; Suganuma, Katsuaki

2014-09-24

11

Tellurides, selenides and associated minerals in the Tunaberg copper deposits, SE Bergslagen, Central Sweden  

Microsoft Academic Search

Summary The Tunaberg copper deposits, SE Bergslagen, Central Sweden, locally contain tellurium and selenium minerals not previously reported from this locality. Hessite, tellurobismutite, tellurium, tetradymite, kawazulite, clausthalite and selenian galena are found as inclusions in bornite and chalcopyrite in a skarn sulphide ore with Cd-rich sphalerite, cobaltite and cobalt pentlandite (assemblage A), and in a skarn iron ore with magnetite

R. T. M. Dobbe

1991-01-01

12

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.

13

Growth and Characterization of the p-type Semiconductors Tin Sulfide and Bismuth Copper Oxy Selenide  

NASA Astrophysics Data System (ADS)

BiCuOSe and SnS are layered, moderate band gap (epsilon G ? 1 eV) semiconductors that exhibit intrinsic p type conductivity. Doping of BiCuOSe with Ca results in a slight expansion of the lattice and an increase of the hole concentration from 10 18 cm--3 to greater than 1020 cm --3. The large carrier density in undoped films is the result of copper vacancies. Mobility is unaffected by doping, remaining constant at 1.5 cm2V--1s--1 in both undoped and doped films, because the Bi-O layers serve as the source of carriers, while transport occurs within the Cu-Se layers. Bi possesses a 6s2 lone pair that was expected to hybridize with the oxygen p states at the top of the valence band, resulting in high hole mobility as compared to similar materials such as LaCuOSe, which lack this lone pair. However, both LaCuOSe and BiCuOSe have similar hole mobility. X-ray absorption and emission spectroscopy, combined with density functional theory calculations, reveal that the Bi 6 s states contribute deep within the valence band, forming bonding and anti-bonding states with O 2p at 11 eV and 3 eV below the valence band maximum, respectively. Hence, the Bi lone pair does not contribute at the top of the valence band and does not enhance the hole mobility. The Bi 6p states contribute at the bottom of the conduction band, resulting in a smaller band gap for BiCuOSe than LaCuOSe (1 eV vs. 3 eV). SnS is a potential photovoltaic absorber composed of weakly coupled layers stacked along the long axis. This weak coupling results in the formation of strongly oriented films on amorphous substrates. The optical band gap is 1.2 eV, in agreement with GW calculations. Absorption reaches 105 cm--1 within 0.5 eV of the band gap. The p type conduction arises from energetically favorable tin vacancies. Variation of growth conditions yields carrier densities of 1014 -- 1016 cm--3 and hole mobility of 7 -- 15 cm2V--1s--1. SnS was alloyed with rocksalt CaS, which was predicted to form a rocksalt structure when the calcium content is increased past 18%. Films of Sn1--x CaxS with x from 0.4 to 0.9 adopt the rocksalt structure with a band gap of 1.1-1.3 eV, with absorption greater than 105 cm--1 within about 0.7 eV of the band gap. The lattice contracts as the calcium content of the films is increased, reaching 5.7 A when x = 0.93. Films are highly insulating, but Seebeck measurements do indicate p type conduction.

Francis, Jason

14

Neutralization by Metal Ions of the Toxicity of Sodium Selenide  

PubMed Central

Inert metal-selenide colloids are found in animals. They are believed to afford cross-protection against the toxicities of both metals and selenocompounds. Here, the toxicities of metal salt and sodium selenide mixtures were systematically studied using the death rate of Saccharomyces cerevisiae cells as an indicator. In parallel, the abilities of these mixtures to produce colloids were assessed. Studied metal cations could be classified in three groups: (i) metal ions that protect cells against selenium toxicity and form insoluble colloids with selenide (Ag+, Cd2+, Cu2+, Hg2+, Pb2+ and Zn2+), (ii) metal ions which protect cells by producing insoluble metal-selenide complexes and by catalyzing hydrogen selenide oxidation in the presence of dioxygen (Co2+ and Ni2+) and, finally, (iii) metal ions which do not afford protection and do not interact (Ca2+, Mg2+, Mn2+) or weakly interact (Fe2+) with selenide under the assayed conditions. When occurring, the insoluble complexes formed from divalent metal ions and selenide contained equimolar amounts of metal and selenium atoms. With the monovalent silver ion, the complex contained two silver atoms per selenium atom. Next, because selenides are compounds prone to oxidation, the stabilities of the above colloids were evaluated under oxidizing conditions. 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB), the reduction of which can be optically followed, was used to promote selenide oxidation. Complexes with cadmium, copper, lead, mercury or silver resisted dissolution by DTNB treatment over several hours. With nickel and cobalt, partial oxidation by DTNB occurred. On the other hand, when starting from ZnSe or FeSe complexes, full decompositions were obtained within a few tens of minutes. The above properties possibly explain why ZnSe and FeSe nanoparticles were not detected in animals exposed to selenocompounds. PMID:23342137

Dauplais, Marc; Lazard, Myriam; Blanquet, Sylvain; Plateau, Pierre

2013-01-01

15

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

16

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

17

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

18

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

19

Copper  

MedlinePLUS

... copper status and certain CVD risk markers in young healthy women. Br J Nutr. 2005;94:231-236. Cassileth B. The Alternative Medicine Handbook: The Complete Reference Guide to Alternative and Complementary Therapies. New York, NY: W.W. Norton; 1998. Castillo-Durán C, Fisberg M, ...

20

Pressure-induced structural transformations in cadmium selenide nanorods  

E-print Network

Pressure-induced structural transformations in cadmium selenide nanorods Nicholas Jabari Lee, Rajiv in cadmium selenide CdSe nanorods are studied using parallel molecular dynamics. Nanorods 4.4 nm in diameter from four- fold wurtzite WZ to six-fold RS coordinated structures in Cadmium selenide CdSe , are also

Southern California, University of

21

An interatomic pair potential for cadmium selenide Eran Rabani  

E-print Network

An interatomic pair potential for cadmium selenide Eran Rabani School of Chemistry, Tel Aviv of interatomic pair potentials for cadmium selenide based on a form similar to the Born­Mayer model. We show in the sixfold-coordinate structure, provides a realistic description of the properties of cadmium selenide

Rabani, Eran

22

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

23

An interatomic pair potential for cadmium selenide  

NASA Astrophysics Data System (ADS)

We have developed a set of interatomic pair potentials for cadmium selenide based on a form similar to the Born-Mayer model. We show that this simple form of the pair potential, which has been used to describe the properties of alkali halides in the sixfold-coordinate structure, provides a realistic description of the properties of cadmium selenide in all three crystal structures: wurtzite, zinc blende, and rocksalt. Using the new pair potential we have studied the pressure-induced phase transition from the fourfold-coordinate wurtzite structure to the sixfold-coordinate rocksalt structure. The pressure transformation and the equation of state are in good agreement with experimental observations. Using the dispersion term in our pair potential we have also calculated the Hamaker constant for cadmium selenide within the framework of the original microscopic approach due to Hamaker. The results indicate that for ionic materials many-body terms that are included in the Lifshitz theory are well captured by the simple pair potential.

Rabani, Eran

2002-01-01

24

Synthesis of diorganyl selenides mediated by zinc in ionic liquid.  

PubMed

A new approach for the synthesis of diorganyl selenides is described. By using economically attractive zinc dust in BMIM-BF(4), a series of diorganyl selenides were efficiently achieved in excellent yields, under neutral reaction conditions. Compared to the usual organic solvents, BMIM-BF(4) exhibited higher performance with the advantage to be reused up to five successive runs. PMID:20438119

Narayanaperumal, Senthil; Alberto, Eduardo E; Gul, Kashif; Rodrigues, Oscar E D; Braga, Antonio L

2010-06-01

25

Cycloaurated triphenylphosphine-sulfide and -selenide.  

PubMed

The first examples of cycloaurated phosphine sulfides and triphenylphosphine selenide have been synthesised; these complexes are fairly rare examples of gold(iii) complexes with potentially reducing sulfur- and selenium-donor ligands. The cycloaurated complex (AuCl(2)(2-C(6)H(4)P(S)Ph(2)) was synthesised in good yield by transmetallation of the organomercury precursor Hg(2-C(6)H(4)P(S)Ph(2))(2) with Me(4)N[AuCl(4)]. A route to the chloro-mercury analogue ClHg(2-C(6)H(4)P(S)Ph(2)) was developed by reaction of the cyclomanganated triphenylphosphine sulfide (CO)(4)Mn(2-C(6)H(4)P(S)Ph(2)) with HgCl(2); this mercury substrate was also used in the synthesis of AuCl(2)(2-C(6)H(4)P(S)Ph(2)). The cycloaurated triphenylphosphine selenide complex AuCl(2)(2-C(6)H(4)P(Se)Ph(2)) was synthesised by an analogous methodology using the new phosphine selenide Hg(2-C(6)H(4)P(Se)Ph(2))(2) [prepared from Hg(2-C(6)H(4)PPh(2))(2) and elemental Se under sonication]. The phosphonamidic analogue AuCl(2)(2-C(6)H(4)P(S)(NEt(2))(2)) has also been synthesised from PhP(S)(NEt(2))(2)via lithiation and mercuration. X-Ray crystal structures of several compounds are reported, and show the presence of puckered ring systems. PMID:20449432

Kilpin, Kelly J; Henderson, William; Nicholson, Brian K

2010-02-21

26

The heat capacity of solid antimony selenide  

Microsoft Academic Search

The literature data on the heat capacity of solid antimony selenide over the temperature range 53 K-T\\u000a m were analyzed. The heat capacity of Sb2Se3 was measured from 350 to 600 K on a DSM-2M calorimeter. The experimental data were used to calculate the dependence C\\u000a \\u000a p\\u000a = a + bT + cT\\u000a ?2 and the thermodynamic functions of solid

A. S. Pashinkin; A. S. Malkova; M. S. Mikhailova

2008-01-01

27

Alloyed Copper Chalcogenide Nanoplatelets via Partial Cation Exchange Reactions  

PubMed Central

We report the synthesis of alloyed quaternary and quinary nanocrystals based on copper chalcogenides, namely, copper zinc selenide–sulfide (CZSeS), copper tin selenide–sulfide (CTSeS), and copper zinc tin selenide–sulfide (CZTSeS) nanoplatelets (NPLs) (?20 nm wide) with tunable chemical composition. Our synthesis scheme consisted of two facile steps: i.e., the preparation of copper selenide–sulfide (Cu2–xSeyS1–y) platelet shaped nanocrystals via the colloidal route, followed by an in situ cation exchange reaction. During the latter step, the cation exchange proceeded through a partial replacement of copper ions by zinc or/and tin cations, yielding homogeneously alloyed nanocrystals with platelet shape. Overall, the chemical composition of the alloyed nanocrystals can easily be controlled by the amount of precursors that contain cations of interest (e.g., Zn, Sn) to be incorporated/alloyed. We have also optimized the reaction conditions that allow a complete preservation of the size, morphology, and crystal structure as that of the starting Cu2–xSeyS1–y NPLs. The alloyed NPLs were characterized by optical spectroscopy (UV–vis–NIR) and cyclic voltammetry (CV), which demonstrated tunability of their light absorption characteristics as well as their electrochemical band gaps. PMID:25050455

2014-01-01

28

Electrometallurgy of copper refinery anode slimes  

NASA Astrophysics Data System (ADS)

High-selenium copper refinery anode slimes form two separate and dynamically evolving series of compounds with increasing electrolysis time. In one, silver is progressively added to non-stoichiometric copper selenides, both those originally present in the anode and those formed subsequently in the slime layer, and in the other, silver-poor copper selenides undergo a dis-continuous crystallographic sequence of anodic-oxidative transformations. The silver-to-selenium molar ratio in the as-cast anode and the current density of electrorefining can be used to construct predominance diagrams for both series and, thus, to predict the final bulk “mineralogy” of the slimes. Although totally incorrect in detail, these bulk data are sufficiently accurate to provide explanations for several processing problems which have been experienced by Kidd Creek Division, Falconbridge Ltd., in its commercial tankhouse. They form the basis for a computer model which predicts final cathode quality from chemical analyses of smelter feed.

Scott, J. D.

1990-08-01

29

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. PMID:19255626

Tepecik, Abdulkadir; Altin, Zehra; Erturan, Seyfettin

2008-01-01

30

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

31

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

PubMed

Luminescent quantum dots were synthesized using bacterially derived selenide (Se(II-)) as the precursor. Biogenic Se(II-) 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 ?-mercaptoethanol-stabilized ZnSe nanoparticles by aqueous synthesis. Biological Se(II-) 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 Se(II-) 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 Se(II-) 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. PMID:23508116

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

2013-04-12

32

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

33

Preparation and Characterization of Silver Selenide Thin Film  

NASA Astrophysics Data System (ADS)

Silver selenide, a phase-changing chalcogenide material, is prepared using electro deposition method for various molarities. X-ray diffraction studies show the cubic lattice of the material. The micro-structural properties such as grain size, strain, dislocation density, and texture coefficient are examined. The lattice constant is calculated using Nelson-Relay function. Morphological studies are done and uniform distributions of grains are observed. High purities of thin films are confirmed by energy dispersive X-ray analysis. The band gap is calculated using UV-vis spectroscopy and photoluminescence technique, and hence, the Stokes's effect is observed in silver selenide thin films. It is the first time that the lattice constant and the Urbach energy for various molarities in the case of silver selenide thin films are reported.

Chandrasekar, L. Bruno; Vijayalakshmi, R.; Rajeswari, B.; Chandramohan, R.; Arivazhagan, G.; Packiaseeli, S. Arulmozhi

2014-09-01

34

Characterization of zinc selenide single crystals  

NASA Technical Reports Server (NTRS)

ZnSe single crystals of high quality and low impurity levels are desired for use as substrates in optoelectronic devices. This is especially true when the device requires the formation of homoepitaxial layers. While ZnSe is commercially available, it is at present extremely expensive due to the difficulty of growing single crystal boules with low impurity content and the resultant low yields. Many researchers have found it necessary to heat treat the crystals in liquid Zn in order to remove the impurities, lower the resistivity and activate the photoluminescence at room temperature. The physical vapor transport method (PVT) has been successfully used at MSFC to grow many single crystals of II-VI semiconducting materials including ZnSe. The main goal at NASA has been to try to establish the effect of gravity on the growth parameters. To this effect, crystals have been grown vertically upwards or horizontally. Both (111) and (110) oriented ZnSe crystals have been obtained via unseeded PVT growth. Preliminary characterization of the horizontally grown crystals has revealed that Cu is a major impurity and that the low temperature photoluminescence spectra is dominated by the copper peak. The ratio of the copper peak to the free exciton peak is being used to determine variations in composition throughout the crystal. It was the intent of this project to map the copper composition of various crystals via photoluminescence first, then measure their electrical resistivity and capacitance as a function of frequency before proceeding with a heat treatment designed to remove the copper impurities. However, equipment difficulties with the photoluminescence set up, having to establish a procedure for measuring the electrical properties of the as-grown crystals and time limitations made us re-evaluate the project goals. Vertically grown samples designated as ZnSe-25 were chosen to be measured electrically since they were not expected to show as much variation in their composition through their cross-section as the horizontally grown samples.

Gerhardt, Rosario A.

1996-01-01

35

Fabrication of core-shell-type copper indium selenide and zinc selenide composite quantum dots and their optical properties.  

PubMed

We successfully fabricated core/shell-type composite QDs based on the ternary-CuInSe2. For the CuInSe2/ZnSe core/shell QDs, an enhanced photoluminescence (PL) emission intensity, such as 16% of the photoluminescence quantum yield (PLQY), and a blue-shift in the emission after the ZnSe coating, were observed. The increase in the PLQY was the result of an exchange of the surface capping ligand from the organic hexadecylamine to the inorganic ZnSe and the smoothing of the confining profile due to the alloying. The blue-shift was attributed to the shrinkage of the effective size of the core-CuInSe2 region due to the partial alloying of the core-CuInSe2 with the ZnSe-shell around their interfaces. For the inverted core/shell QDs, i.e., the nominally ZnSe/CuIn5Se8 core/shell QDs, they showed a red emission at 619 nm. The emission wavelength is the shortest among the previously reported QDs in Cu-In-Se system. PMID:21770109

Omata, Takahisa; Nosel, Katsuhiro; Otsuka-Yao-Matsuo, Shinya

2011-06-01

36

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

37

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

38

XPS and XES emission investigations of d–p resonance in some copper chalcogenides  

Microsoft Academic Search

Investigations of binary and ternary copper tellurides and selenides electron energy spectra are of interest because of the considerable sensitivity of their electrophysical and optical properties to the stoichiometry of these compounds. Ab initio theoretical calculations for these non-stoichiometric AI2?xBVI compounds are difficult due to the existence of 3d-electrons in copper. Thus investigations of their band structure and electron density

E. P. Domashevskaya; V. V. Gorbachev; V. A. Terekhov; V. M. Kashkarov; E. V. Panfilova; A. V. Shchukarev

2001-01-01

39

Convenient synthesis of unsymmetrical organochalcogenides using organoboronic acids with dichalcogenides via cleavage of the S-S, Se-Se, or Te-Te bond by a copper catalyst.  

PubMed

This article describes the methodology for a copper-catalyzed preparation of numerous monochalcogenides from dichalcogenides with organoboronic acids. Unsymmetrical diorgano-monosulfides, selenides, and tellurides can be synthesized by the coupling of dichalcogenides with aryl- or alkylboronic acids using a copper catalyst in air. The present reaction can take advantage of both organochalcogenide groups on dichalcogenide. PMID:17288374

Taniguchi, Nobukazu

2007-02-16

40

Preparation of Cadmium Selenide-Polyolefin Composites from Functional Phosphine Oxides and Ruthenium-Based  

E-print Network

Preparation of Cadmium Selenide-Polyolefin Composites from Functional Phosphine OxidesVersity of Massachusetts, Amherst, Massachusetts 01003 Received November 21, 2001 Abstract: Cadmium selenide nanoparticles by employing more easily handled cadmium sources, such as CdO. Both methods give well-defined nanoparticles

41

Organoselenium bis selenide attenuates 3-nitropropionic acid-induced neurotoxicity in rats.  

PubMed

This study was designed to evaluate the effects of bis selenide on Huntington disease (HD)-like signs induced by 3-nitropropionic acid (3-NP) in rats. To this aim, rats were treated for 4 days with bis selenide (5 or 20 mg/kg/day, per oral) 30 min before 3-NP (20 mg/kg/day, intraperitoneally). The body weight gain, locomotor activity, motor coordination, and biochemical parameters in striatal preparations were assessed 24 h after the last injection of 3-NP. The highest dose of bis selenide was effective in protecting against body weight loss and motor coordination deficit induced by 3-NP. The impairment of locomotor activity caused by 3-NP was abolished by bis selenide at both doses. Bis selenide (5 and 20 mg/kg) partially restored succinate dehydrogenase activity inhibited after 3-NP exposure. The dose of 20 mg/kg of bis selenide recovered partially ?-aminolevulinic acid dehydratase activity, and totally Na(+), K(+)-ATPase activity, two sulfhydryl enzymes sensitive to oxidizing agents, which had their activities inhibited by 3-NP. Also, 3-NP led to an increase in protein carbonyl levels and glutathione reductase activity and inhibited catalase activity-alterations that were reversed by bis selenide administration at both doses. The highest dose of bis selenide was effective against the increase of RS levels, the depletion of reduced glutathione content, and the inhibition of glutathione peroxidase activity induced by 3-NP. Bis selenide was not effective against inhibition of SOD activity caused by 3-NP. These findings demonstrate that bis selenide elicited protective effects against HD-like signs induced by 3-NP in rats. PMID:22739838

Bortolatto, Cristiani F; Jesse, Cristiano R; Wilhelm, Ethel A; Chagas, Pietro M; Nogueira, Cristina W

2013-04-01

42

Synthesis and characterization of inorganic-organic hybrid gallium selenides.  

PubMed

Two semiconducting hybrid gallium selenides, [Ga6Se9(C6H14N2)4][H2O] (1) and [C6H14N2][Ga4Se6(C6H14N2)2] (2), were prepared using a solvothermal method in the presence of 1,2-diaminocyclohexane (1,2-DACH). Both materials consist of neutral inorganic layers, in which 1,2-DACH is covalently bonded to gallium. In 1, the organic amine acts as a monodentate and a bidentate ligand, while in 2, bidentate and uncoordinated 1,2-DACH molecules coexist. PMID:25113435

Ewing, Sarah J; Vaqueiro, Paz

2014-09-01

43

Fractal simulation of the resistivity and capacitance of arsenic selenide  

SciTech Connect

The temperature dependences of the ac resistivity R and ac capacitance C of arsenic selenide were measured more than four decades ago [V. I. Kruglov and L. P. Strakhov, in Problems of Solid State Electronics, Vol. 2 (Leningrad Univ., Leningrad, 1968)]. According to these measurements, the frequency dependences are R {proportional_to} {omega}{sup -0.80{+-}0.01} and {Delta}C {proportional_to} {omega}{sup -0.120{+-}0.006} ({omega} is the circular frequency and {Delta}C is measured from the temperature-independent value C{sub 0}). According to fractal-geometry methods, R {proportional_to} {omega}{sup 1-3/h} and {Delta}C {proportional_to} {omega}{sup -2+3/h}, where h is the walk dimension of the electric current in arsenic selenide. Comparison of the experimental and theoretical results indicates that the walk dimensions calculated from the frequency dependences of resistivity and capacitance are h{sub R} = 1.67 {+-} 0.02 and h{sub C} = 1.60 {+-} 0.08, which are in agreement with each other within the measurement errors. The fractal dimension of the distribution of conducting sections is D = 1/h = 0.6. Since D < 1, the conducting sections are spatially separated and form a Cantor set.

Balkhanov, V. K., E-mail: ballar@yandex.ru; Bashkuev, Yu. B. [Russian Academy of Sciences, Division of Physical Problems, Buryat Scientific Center, Siberian Branch (Russian Federation)

2010-03-15

44

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

Microsoft Academic Search

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

Vipul Kheraj; K. K. Patel; S. J. Patel

2013-01-01

45

Copper Test  

MedlinePLUS

... 3. What happens if I am exposed to toxic amounts of copper? Copper poisoning can cause vomiting ... Asked Questions American Cancer Society: Copper Agency for Toxic Substances and Disease Registry: Public Health Statement for ...

46

Chromium-doped zinc selenide gain media: From synthesis to pulsed mid-infrared laser operation  

E-print Network

This paper provides an overview of the experimental work performed in our research group on the synthesis, spectroscopic investigation, and laser characterization of chromium-doped zinc selenide (Cr[superscript 2+]:ZnSe). ...

Demirbas, Umit

47

On precise determination of structural and dynamic characteristics of the hydrogen selenide molecule from experimental data  

NASA Astrophysics Data System (ADS)

We realized the method for determining the potential function of the segregated electron state of a polyatomic molecule from experimental data using a hydrogen selenide molecule as an example. Dependences of various spectroscopic parameters on the parameters of the potential function in the natural coordinates were studied. From the obtained data, the potential function of the hydrogen selenide molecule was reconstructed up to the fourth order of smallness.

Sinitsyn, E. A.; Bekhtereva, E. S.; Bulavenkova, A. S.; Ulenikov, O. N.

2007-09-01

48

Observation of inverse spin Hall effect in bismuth selenide  

NASA Astrophysics Data System (ADS)

Bismuth Selenide (Bi2Se3) is a topological insulator exhibiting helical spin polarization and strong spin-orbit coupling. The spin-orbit coupling links the charge current to spin current via the spin Hall effect (SHE). We demonstrate a Bi2Se3 spin detector by injecting the pure spin current from a magnetic permalloy layer to a Bi2Se3 thin film and detect the inverse SHE in Bi2Se3. The spin Hall angle of Bi2Se3 is found to be 0.0093 ± 0.0013 and the spin diffusion length in Bi2Se3 to be 6.2 ± 0.15 nm at room temperature. Our results suggest that topological insulators with strong spin-orbit coupling can be used in functional spintronic devices.

Deorani, Praveen; Son, Jaesung; Banerjee, Karan; Koirala, Nikesh; Brahlek, Matthew; Oh, Seongshik; Yang, Hyunsoo

2014-09-01

49

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

50

Intrinsic high-temperature superconductivity in ternary iron selenides  

NASA Astrophysics Data System (ADS)

We examine superconductivity in the mesoscopically mixed antiferromagnetic (AF) and superconducting (SC) phases of ternary iron selenides KyFe2-xSe2. It is shown that the interlayer hopping and AF order are key factors to determine Tc of the SC phase. In general, the hopping will produce deformed Fermi surfaces (FSs) that tend to suppress superconductivity. However, contrary to the common expectation, we find that larger AF order actually results in larger SC order, which explains the observed relatively high Tc in these phases. Furthermore, our results indicate that by reducing the interlayer hopping appropriately, phase-separated KyFe2-xSe2 may exhibit its intrinsic SC phase in the two-dimensional limit with a much higher Tc (˜65K) than what has been observed.

Huang, Shin-Ming; Mou, Chung-Yu; Lee, Ting-Kuo

2013-11-01

51

Electrochemical and spectroscopic study of C 12H 25X molecules adsorption on copper sheets, X (–SH, –S–S–, –SeH and –Se–Se–)  

Microsoft Academic Search

In this contribution, we explored the possibility of using selenol and selenide molecules to form self-assembled monolayers (SAMs) on copper, in order to check the influence of anchoring groups on SAMs quality and compared it to well-known thiolate assemblies (formed with thiol and disulfide molecules). Precisely, monolayers of pure alkane chains have been self-assembled on electroreduced bulk copper. The different

G. Fonder; C. Volcke; B. Csoka; J. Delhalle; Z. Mekhalif

2010-01-01

52

Diselenides and allyl selenides as glutathione peroxidase mimetics. Remarkable activity of cyclic seleninates produced in situ by the oxidation of allyl omega-hydroxyalkyl selenides.  

PubMed

A series of aliphatic diselenides and selenides containing coordinating substituents was tested for glutathione peroxidase (GPx)-like catalytic activity in a model system in which the reduction of tert-butyl hydroperoxide with benzyl thiol to afford dibenzyl disulfide and tert-butyl alcohol was performed under standard conditions and monitored by HPLC. Although the diselenides showed generally poor catalytic activity, allyl selenides proved more effective. In particular, allyl 3-hydroxypropyl selenide (25) rapidly generated 1,2-oxaselenolane Se-oxide (31) in situ by a series of oxidation and [2,3]sigmatropic rearrangement steps. The remarkably active cyclic seleninate 31 proved to be the true catalyst, reacting with the thiol via a postulated mechanism in which the thioseleninate 32 is first produced, followed by further thiolysis to selenenic acid 33 and oxidation-dehydration to regenerate 31. In contrast to catalysis with GPx, formation of the corresponding selenenyl sulfide 34 comprises a competing deactivation pathway in the catalytic cycle of 31, as a separate experiment revealed that authentic 34 was a much less effective catalyst than 31. 1,2-Oxaselenane Se-oxide (37), the six-membered homologue of 31, was formed similarly from allyl 4-hydroxybutyl selenide (26), but proved a less effective catalyst than 31. Compounds 31 and 37 are the first examples of unsubstituted monocyclic seleninate esters. PMID:14583041

Back, Thomas G; Moussa, Ziad

2003-11-01

53

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

54

Synthesis of colloidal nanoscaled copper-indium-gallium-selenide (CIGS) particles for photovoltaic applications.  

PubMed

In this work, Cu(In,Ga)Se(2) (CIGS) nanoparticles were synthesized using a wet chemical method. The method is based on a non-vacuum thermal process that does not use selenization. The effects of temperature, source materials, and growth conditions on the phase and particle size were investigated. X-ray diffraction results confirm the formation of a tetragonal CIGS structure as the main phase with the purity more than 99% obtained by energy-dispersive X-ray spectroscopy (EDX). The morphology and size of the samples were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Using these methods, 20-80nm particles were obtained. Through measurements of the absorption spectra of CIGS nanoparticles, the band gap of the synthesized material was determined to be about 1.44eV, which corresponds to an acceptable wavelength region for absorber layers in solar cells. PMID:22762985

Mousavi, S H; Müller, T S; de Oliveira, P W

2012-09-15

55

Structure-fluctuation-induced abnormal thermoelectric properties in semiconductor copper selenide  

SciTech Connect

Thermoelectric effects and related technologies have attracted a great interest due to the world-wide energy harvesting. Thermoelectricity has usually been considered in the context of stable material phases. Here we report that the fluctuation of structures during the second-order phase transition in Cu2Se semiconductor breaks the conventional trends of thermoelectric transports in normal phases, leading to a critically phase-transition-enhanced thermoelectric figure of merit zT above unity at 400K, a three times larger value than for the normal phases. Dynamic structural transformations introduce intensive fluctuations and extreme complexity, which enhance the carrier entropy and thus the thermopower, and strongly scatter carriers and phonons as well to make their transports behave critically.

Liu, Huili [Chinese Academy of Sciences; Shi, Xun [Chinese Academy of Sciences; Kirkham, Melanie J [ORNL; Wang, Hsin [ORNL; Li, Qiang [Brookhaven National Laboratory (BNL); Uher, Ctirad [University of Michigan; Zhang, Wenqing [Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS); Chen, Lidong [Chinese Academy of Sciences

2013-01-01

56

Methylation and demethylation of intermediates selenide and methylselenol in the metabolism of selenium  

SciTech Connect

All nutritional selenium sources are transformed into the assumed common intermediate selenide for the syntheses of selenoproteins for utilization and/or of selenosugar for excretion. Methylselenol [monomethylselenide, MMSe] is the assumed intermediate leading to other methylated metabolites, dimethylselenide (DMSe) and trimethylselenonium (TMSe) for excretion, and also to the intermediate selenide from methylselenocysteine and methylseleninic acid (MSA). Here, related methylation and demethylation reactions were studied in vitro by providing chemically reactive starting substrates ({sup 76}Se-selenide, {sup 77}Se-MMSe and {sup 82}Se-DMSe) which were prepared in situ by the reduction of the corresponding labeled proximate precursors ({sup 76}Se-selenite, {sup 77}Se-MSA and {sup 82}Se-dimethylselenoxide (DMSeO), respectively) with glutathione, the three substrates being incubated simultaneously in rat organ supernatants and homogenates. The resulting chemically labile reaction products were detected simultaneously by speciation analysis with HPLC-ICP-MS after converting the products and un-reacted substrates to the corresponding oxidized derivatives (selenite, MSA and DMSeO). The time-related changes in selenium isotope profiles showed that demethylation of MMSe to selenide was efficient but that of DMSe to MMSe was negligible, whereas methylation of selenide to MMSe, and MMSe to DMSe were efficient, and that of DMSe to TMSe occurred less efficiently. The present methylation and demethylation reactions on equilibrium between selenide, MMSe and DMSe without producing selenosugar and selenoproteins indicated that DMSe rather than TMSe is produced as the end product, suggesting that DMSe is to be excreted more abundantly than TMSe. Organ-dependent differences in the methylation and demethylation reactions were characterized for the liver, kidney and lung.

Ohta, Yuki [Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo, Chiba 260-8675 (Japan); Suzuki, Kazuo T. [Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo, Chiba 260-8675 (Japan)], E-mail: ktsuzuki@p.chiba-u.ac.jp

2008-01-15

57

Solid-gas phase equilibria and thermodynamic properties of cadmium selenide.  

NASA Technical Reports Server (NTRS)

Accurate vapor pressures are determined through direct weight loss measurements using the Knudsen effusion technique. The experimental data are evaluated by establishing the mode of vaporization and determining the heat capacity of cadmium selenide at elevated temperatures. Additional information is obtained through a second- and third-law evaluation of data, namely, the heat of formation and the absolute entropy of cadmium selenide. A preferential loss of selenium during the initial heating of CdSe is observed, which leads to a deviation in stoichiometry.

Sigai, A. G.; Wiedemeier, H.

1972-01-01

58

Preface – Special Issue: Telluride and selenide minerals in gold deposits – how and why?  

Microsoft Academic Search

Tellurides (and selenides) of Au, Ag, Bi, Pb, and other elements are commonly reported as trace minerals associated with gold in metallogenetic belts and regions of various ages, and in individual deposits that span the magmatic-hydrothermal spectrum, as well as those formed in metamorphic terranes (e.g., Cook and Ciobanu, 2005 and references therein). The association among tellurium, selenium and gold

C. L. Ciobanu; N. J. Cook; P. G. Spry

2006-01-01

59

Electron Transport in a Multichannel One-Dimensional Conductor: Molybdenum Selenide Nanowires  

E-print Network

Electron Transport in a Multichannel One-Dimensional Conductor: Molybdenum Selenide Nanowires Latha-dimensional (1D) metals constitute a Luttinger liquid (LL) [1], in contrast to a Fermi liquid (FL) in three-dimensional (3D) metals. Transport properties of 1D conductors are strongly modi- fied as adding an electron

Venkataraman, Latha

60

Electroelastic Properties of the Sulfides, Selenides, and Tellurides of Zinc and Cadmium  

Microsoft Academic Search

A complete set of elastic, piezoelectric, and dielectric constants is presented for the sulfides, selenides, and tellurides of zinc and cadmium. The piezoelectric constants for the hexagonal crystals in this group are markedly higher than for the cubic crystals. An elementary model theory applied to these data leads to electric charges on the metal atom increasing from +0.066 e for

Don Berlincourt; Hans Jaffe; L. R. Shiozawa

1963-01-01

61

Enhancement of thermoelectric figure-of-merit by resonant states of aluminium doping in lead selenide  

E-print Network

By adding aluminium (Al) into lead selenide (PbSe), we successfully prepared n-type PbSe thermoelectric materials with a figure-of-merit (ZT) of 1.3 at 850 K. Such a high ZT is achieved by a combination of high Seebeck ...

Zhang, Qinyong

62

Dispersion strengthened copper  

DOEpatents

A composition of matter 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, and a method for making this composition of matter.

Sheinberg, Haskell (Los Alamos, NM); Meek, Thomas T. (Knoxville, TN); Blake, Rodger D. (Santa Fe, NM)

1990-01-01

63

Dispersion strengthened copper  

DOEpatents

A composition of matter 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, and a method for making this composition of matter.

Sheinberg, Haskell (Los Alamos, NM); Meek, Thomas T. (Knoxville, TN); Blake, Rodger D. (Santa Fe, NM)

1989-01-01

64

New group 11 complexes with metal-selenium bonds of methyldiphenylphosphane selenide: a solid state, solution and theoretical investigation.  

PubMed

Reactions between methyldiphenylphosphane selenide, SePPh(2)Me, and different group 11 metal starting materials {CuCl, [CuNO(3)(PPh(3))(2)], AgOTf, [AgOTf(PPh(3))] (OTf = OSO(2)CF(3)), [AuCl(tht)], [Au(C(6)F(5))(tht)] and [Au(C(6)F(5))(3)(tht)] (tht = tetrahydrothiophene)} were performed in order to obtain several new species with metal-selenium bonds. The new complexes [CuCl(SePPh(2)Me)] (1), [AgOTf(SePPh(2)Me)] (2), [AuCl(SePPh(2)Me)] (5), [Au(C(6)F(5))(SePPh(2)Me)] (6) and [Au(C(6)F(5))(3)(SePPh(2)Me)] (7) were isolated and structurally characterized in solution by multinuclear NMR spectroscopy ((1)H, (31)P, (77)Se and (19)F where appropriate). Solid products were isolated also from the reactions between SePPh(2)Me and [CuNO(3)(PPh(3))(2)] or [AgOTf(PPh(3))], respectively. NMR experiments, including low temperature (1)H and (31)P NMR, revealed for them a dynamic behaviour in solution, involving the transfer of selenium from PPh(2)Me to PPh(3). In case of the isolated silver(i) containing solid an equilibrium between, respectively, monomeric [AgOTf(PPh(3))(SePPh(2)Me)] (3) and [AgOTf(PPh(2)Me)(SePPh(3))] (4), and dimeric [Ag(PPh(3))(?-SePPh(2)Me)](2)(OTf)(2) (3a) and [Ag(PPh(2)Me)(?-SePPh(3))](2)(OTf)(2) (4a) species was observed in solution. In case of the isolated copper(i) containing solid the NMR studies brought no clear evidence for a similar behaviour, but it can not be excluded in a first stage of the reaction. However the transfer of selenium between the two triorganophosphanes takes place also in this case, but the NMR spectra suggest that the final reaction mixture contains the free triorganophospane selenides SePPh(2)Me and SePPh(3) as well as the complex species [CuNO(3)(PPh(3))(2)], [CuNO(3)(PPh(2)Me)(2)] and [CuNO(3)(PPh(3))(PPh(2)Me)] in equilibrium. Single-crystal X-ray diffraction studies revealed monomeric structures for the gold(I) 6 and gold(III) 7 complexes. In case of compound 6 weak aurophilic gold(I)···gold(I) contacts were also observed in the crystal. DFT calculations were performed in order to understand the solution behaviour of the silver(I) and copper(I) species containing both P(III) and P(V) ligands, to verify the stability of possible dimeric species and to account for the aurophilic interactions found for 6. In addition, the nature of the electronic transitions involved in the absorption/emission processes observed for 6 and 7 in the solid state were also investigated by means of TD-DFT calculations. PMID:21993712

Pop, Alexandra; Silvestru, Anca; Gimeno, M Concepción; Laguna, Antonio; Kulcsar, Monika; Arca, Massimiliano; Lippolis, Vito; Pintus, Anna

2011-12-14

65

Bis-vinyl selenides obtained via iron(III) catalyzed addition of PhSeSePh to alkynes: synthesis and antinociceptive activity.  

PubMed

In the present study the synthesis and antinociceptive activity of bis-vinyl selenides, prepared via FeCl(3) promoted reaction addition of diorganyl dichalcogenides to alkynes, is described. The pharmacological results demonstrated that bis-vinyl selenides 3a, 3d, 3h and 3t elicited antinociceptive effect in the mouse formalin test. The antinociceptive effects of bis-vinyl selenides are not sensitive to electronic effects of the substituents on the aromatic ring directly bonded to the selenium atom. Bis-vinyl selenides 3h and 3t were the most promising molecules for pharmacological purposes since these bis-vinyl selenides were effective in both phases of the formalin test and against edema. A single dose of bis-vinyl selenides 3a, 3d, 3h and 3t did not cause acute toxicity in mice. PMID:23314037

Sartori, Glaubia; Neto, José S S; Pesarico, Ana Paula; Back, Davi F; Nogueira, Cristina W; Zeni, Gilson

2013-02-21

66

Theory of two-magnon Raman scattering in alkaline iron selenide superconductors  

NASA Astrophysics Data System (ADS)

Motivated by the recent experiment of two-magnon Raman scattering in alkaline iron selenide superconductors (Zhang et al., 2012), we investigate in details the underlying spin interactions of the ?{5}×?{5} antiferromagnetic superstructure. Based on the linear spin wave approximation, the Fleury-London (FL) two-magnon Raman cross-sections are calculated. By comparing theoretical results with the Raman data in both Ag and Bg channels, an optimal set of exchange parameters which are consistent with the fitting to the neutron scattering data are obtained. It reveals that the experimentally observed broad and asymmetric peaks around 1600 cm-1 are dominantly originated from quasiparticle excitations in two nearly degenerate magnon bands in the (0,±?) and (±?,0) directions. The result thus supports that the magnetic properties in alkaline iron selenide AFe1.6+xSe6 superconductors can be basically described by the quantum spin model with up to third nearest-neighbor exchange couplings.

Liu, C. S.; Zhang, A. M.; Xu, T. F.; Wu, W. C.

2014-11-01

67

Shape-controlled colloidal synthesis of rock-salt lead selenide nanocrystals.  

PubMed

Developing simple synthetic methods to control the size and morphology of nanocrystals is an active area of research as these parameters control the material's electronic and optical properties. For a semiconductor with a symmetrical crystal structure such as lead selenide, anisotropic colloidal growth has been previously accomplished via the use of templates, seeds, or by block assembly of smaller, symmetrical subunits. Here, we present a simple method to create monodisperse lead selenide nanorods and multipods at low temperatures. The size distribution and the observed morphologies are consistent with a continuous, anisotropic growth of material. The syntheses of these anisotropic shapes are due to the nature of the nuclei that form upon injection of precursors into partially oxidized alkene solvents that may contain lactone and carbonate-functional derivatives. PMID:21770427

Jawaid, Ali M; Asunskis, Daniel J; Snee, Preston T

2011-08-23

68

Recovery of Silver and Gold from Copper Anode Slimes  

NASA Astrophysics Data System (ADS)

Copper anode slimes, produced from copper electrolytic refining, are important industrial by-products containing several valuable metals, particularly silver and gold. This article provides a comprehensive overview of the development of the extraction processes for recovering silver and gold from conventional copper anode slimes. Existing processes, namely pyrometallurgical processes, hydrometallurgical processes, and hybrid processes involving the combination of pyrometallurgical and hydrometallurgical technologies, are discussed based in part on a review of the form and characteristics of silver and gold in copper anode slimes. The recovery of silver and gold in pyrometallurgical processes is influenced in part by the slag and matte/metal chemistry and related characteristics, whereas the extraction of these metals in hydrometallurgical processes depends on the leaching reagents used to break the structure of the silver- and gold-bearing phases, such as selenides. By taking advantage of both pyrometallurgical and hydrometallurgical techniques, high extraction yields of silver and gold can be obtained using such combined approaches that appear promising for efficient extraction of silver and gold from copper anode slimes.

Chen, Ailiang; Peng, Zhiwei; Hwang, Jiann-Yang; Ma, Yutian; Liu, Xuheng; Chen, Xingyu

2014-09-01

69

Synthesis of metal selenide colloidal nanocrystals by the hot injection of selenium powder.  

PubMed

We describe the synthesis of metal selenide nanocrystals, including CdSe, ZnSe, CuInSe2 and Cu2(Zn,Sn)Se4, by the hot injection of selenium powder dispersed in a carrier solvent. Since this results in a fast and high yield nanocrystal formation, we argue that the approach is well suited for the low cost, large volume production of nanocrystals. PMID:23657539

Flamee, Stijn; Dierick, Ruben; Cirillo, Marco; Van Genechten, Dirk; Aubert, Tangi; Hens, Zeger

2013-09-21

70

Hypochlorous acid turn-on fluorescent probe based on oxidation of diphenyl selenide.  

PubMed

A BODIPY-based fluorescent probe, HCSe, has been successfully developed for the rapid detection of hypochlorous acid based on the specific HOCl-promoted oxidation of diphenyl selenide in response to the amount of HOCl. Confocal fluorescence microscopy imaging using RAW264.7 cells showed that the new probe HCSe could be used as an effective fluorescent probe for detecting HOCl in living cells. PMID:23373559

Liu, Shi-Rong; Wu, Shu-Pao

2013-02-15

71

Self-Diffusion of Lead210 in Single Crystals of Lead Selenide  

Microsoft Academic Search

Self-diffusion of Pb-210 in lead selenide has been studied in an inert atmosphere as a function of temperature (over the range 400–800°C) and defect concentration introduced by doping. Diffusion measurements were performed on specimens of p-type PbSe containing 1018 holes per cc and on specimens doped with ½ mole % Bi2Se3 to give n-type material with 5×1019 electrons per cc

Martin S. Seltzer; J. Bruce Wagner

1962-01-01

72

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

1997-10-01

73

Copper-catalyzed synthesis of ?-haloalkenyl chalcogenides by addition of dichalcogenides to internal alkynes and its application to synthesis of ( Z)-tamoxifen  

Microsoft Academic Search

A copper-catalyzed synthesis of ?-haloalkenyl sulfides or selenides was carried out by addition of dichalcogenides and tetrabutylammonium halides to internal alkynes. The present reaction anti- and regio-selectively afforded the corresponding alkenyl chalocogenides, and took advantage of both organochalcogenide-groups on dichalcogenide. Furthermore, the reaction under oxygen atmosphere could employ thiols. The use of the procedure could easily synthesize (Z)-tamoxifen from diphenyl

Nobukazu Taniguchi

2009-01-01

74

Design and performance considerations for the development of hydrogen selenide effluent processing systems  

NASA Astrophysics Data System (ADS)

One of the gases which may be used in processes for fabrication of electro-optical materials including some solar cells is hydrogen selenide. This gas is included in the Environmental Protection Agency (EPA) list of toxic chemicals and requires care in use and treatment. No data were identified in the literature relating to scrubbing or other processes which have been used to control process effluents. This paper presents and discusses criteria for the development of an effective scrubbing system to handle hydrogen selenide based on current emission standards. Problems considered include the development of reactor and piping enclosure scrubbers as well as scrubbers for the effluent gas stream. Extrapolation of available data was used to predict performance of scrubbers based on typical designs. Data for the operation of a dual scrubbing system are presented which show that emissions of hydrogen selenide can be reduced well below threshold limit value (TLV) for a range of gas throughput rates. Future areas of research for improving cost effectiveness and capacity are discussed.

Bottenberg, Willaim R.; Khanna, Ashok; Sproull, Robert D.

1988-07-01

75

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

76

Magnesium-induced copper-catalyzed synthesis of unsymmetrical diaryl chalcogenide compounds from aryl iodide via cleavage of the Se-Se or S-S bond.  

PubMed

The methodology for a copper-catalyzed preparation of diaryl chalcogenide compounds from aryl iodides and diphenyl dichalcogenide molecules is reported. Unsymmetrical diaryl sulfide or diaryl selenide can be synthesized from aryl iodide and PhYYPh (Y = S, Se) with a copper catalyst (CuI or Cu(2)O) and magnesium metal in one pot. This reaction can be carried out under neutral conditions according to an addition of magnesium metal as the reductive reagent. Furthermore, it is efficiently available for two monophenylchalcogenide groups generated from diphenyl dichalcogenide. PMID:14750822

Taniguchi, Nobukazu; Onami, Tetsuo

2004-02-01

77

Selenide and telluride glasses for mid-infrared bio-sensing  

NASA Astrophysics Data System (ADS)

Fiber Evanescent Wave Spectroscopy (FEWS) is an efficient way to collect optical spectra in situ, in real time and even, hopefully, in vivo. Thanks to selenide glass fibers, it is possible to get such spectra over the whole mid-infrared range from 2 to 12 ?m. This working window gives access to the fundamental vibration band of most of biological molecules. Moreover selenide glasses are stable and easy to handle, and it is possible to shape the fiber and create a tapered sensing head to drastically increase the sensitivity. Within the past decades, numerous multi-disciplinary studies have been conducted in collaboration with the City Hospital of Rennes. Clinical trials have provided very promising results in biology and medicine which have led to the creation in 2011 of the DIAFIR Company dedicated to the commercialization of fiber-based infrared biosensors. In addition, new glasses based on tellurium only have been recently developed, initially in the framework of the Darwin mission led by the European Space Agency (ESA). These glasses transmit light further into the far-infrared and could also be very useful for medical applications in the near future. Indeed, they permit to reach the vibrational bands of biomolecules laying from 12 to 16 ?m where selenide glasses do not transmit light anymore. However, while Se is a very good glass former, telluride glasses tend to crystallize easily due to the metallic nature of Te bonds. Hence, further work is under way to stabilize the glass composition for fibers drawing and to lower the optical losses for improving their sensitivity as bio-sensors.

Cui, Shuo; Chahal, Radwan; Shpotyuk, Yaroslav; Boussard, Catherine; Lucas, Jacques; Charpentier, Frederic; Tariel, Hugues; Loréal, Olivier; Nazabal, Virginie; Sire, Olivier; Monbet, Valérie; Yang, Zhiyong; Lucas, Pierre; Bureau, Bruno

2014-02-01

78

[Effect of silver/zinc selenide core-shell structure spheres on the infrared absorption properties of sodium nitrate].  

PubMed

Silver/zinc selenide (Ag/ZnSe) core-shell structure spheres were made through the method of silver mirror reaction on zinc selenide micro spheres. Surface morphology of the spheres was depicted by scanning electron microscopy, X-ray diffraction and Fourier infrared absorption spectrum. This paper studies the effect of Ag/ZnSe core-shell structure spheres on the infrared absorption properties of sodium nitrate solution. The results show that, the anti-symmetric vibration absorption peaks of nitrate are blue-shifted, and the intensity are improved obviously by the effect of core-shell structure spheres. PMID:24409704

Guo, Qiang; Li, Chun; Jia, Zhi-Jun; Yuan, Guang

2013-10-01

79

Scaling and spatial analysis of the dielectric response of cadmium selenide nanowires  

NASA Astrophysics Data System (ADS)

Transverse dielectric response of hexagonal cadmium selenide (CdSe) nanowires was investigated using first-principles quantum mechanical calculations. Scaling behavior of polarizability was found to closely follow a simple dielectric cylinder model even for small nanowires with a diameter of a few nanometers. The spatial dependence of the dielectric response in the nanowires was analyzed in terms of maximally localized Wannier functions in order to elucidate the model behavior. Localized d electrons at cadmium atoms were found responsible for the simple analytic scaling of the polarizability, and the dielectric response in the center of nanowire was found converged to that of bulk already for 3 nm diameter nanowires.

Kanai, Yosuke; Cicero, Giancarlo

2014-10-01

80

The effects of pressure on the elastic constants of mercury selenide up to the phase transition  

Microsoft Academic Search

From measurements of ultrasonic wave velocities the elastic constants of mercury selenide, HgSe, have been obtained as a function of hydrostatic pressure up to that (Pt=9.5*108 Pa=9.5 kbar) at which the densification phase transition to the cinnabar structure takes place. At room temperature the elastic constants are at atmospheric pressure C11=62.2, C44=22.7, C'(=1\\/2(C11-C12))=7.9, and at 8.5*108 Pa C11=62.5, C44=22.0, C'=7.37

P. J. Ford; A. J. Miller; G. A. Saunders; Y. K. Yogurtcu; J. K. Furdyna; M. Jaczynski

1982-01-01

81

Nondestructive analysis of single crystals of selenide spinels by X-ray spectrometry techniques  

Microsoft Academic Search

The paper presents possibilities and difficulties in nondestructive analysis of small multielement single crystals performed\\u000a by means of X-ray spectrometry techniques: micro-X-ray fluorescence spectrometry (?-XRF), energy-dispersive electron probe\\u000a microanalysis (ED-EPMA), and X-ray photoelectron spectroscopy (XPS). The capability of the X-ray spectroscopy techniques in\\u000a elemental analysis is demonstrated with the single crystals of selenide spinels of the general formula M\\u000a x

E. Malicka; R. Sitko; B. Zawisza; J. Heimann; D. Kajewski; A. Kita

2011-01-01

82

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

83

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

84

Biological interaction between transition metals (Ag, Cd and Hg), selenide/sulfide and selenoprotein P.  

PubMed

The interaction between transition metals (Ag+, Cd2+ and Hg2+) and selenium (Se) in the bloodstream was studied in vitro by means of the HPLC--inductively coupled argon plasma-mass spectrometry (ICP MS) method. Transition metal ions and selenide (produced in vitro from selenite in the presence of glutathione) or sulfide (Na2S) formed a (metal-Se/S) complex, which then bound to a plasma protein, selenoprotein P (Sel P), to form a ternary complex, (metal-Se/S)-Sel P. The molar ratios of metals to Se were 1:1 for Hg/Se and Cd/Se, but either 1:1 or 2:1 for Ag/Se, depending on the ratio of their doses. The results indicate that the interaction between transition metals and Se occurs through the general mechanism, i.e., transition metal ions and selenide form the unit complex (metal-Se)n, and then the complex binds to selenoprotein P to form the ternary complex ¿(metal-Se)n¿m--seleno-protein P in the bloodstream. PMID:9833321

Sasakura, C; Suzuki, K T

1998-09-01

85

An Selenide-Based Approach to Photochemical Cleavage of Peptide and Protein Backbones at Engineered Backbone Esters  

PubMed Central

A strategy for photochemical cleavage of peptide and protein backbones is described, which is based on a selenide-mediated cleavage of a backbone ester moiety. Studies in model systems establish the viability of the chemistry and suggest the method could be a valuable tool for chemical biology studies of proteins. PMID:19902952

Eastwood, Amy L.; Blum, Angela P.; Zacharias, Niki M.; Dougherty, Dennis A.

2010-01-01

86

Chemical Bath Deposited Zinc Sulfide Buffer Layers for Copper Indium Gallium Sulfur-selenide Solar Cells and Device Analysis  

SciTech Connect

Cd free CIGSS thin film solar cell structures with a MgF2/TCO/CGD-ZnS/CIGSS/Mo/SLG structure have been fabricated using chemical bath deposited (CBD)-ZnS buffer layers and high quality CIGSS absorber layers supplied from Shell Solar Industries. The use of CBD-ZnS, which is a higher band gap materials than CdS, improved the quantum efficiency of fabricated cells at lower wavelengths, leading to an increase in short circuit current. The best cell to date yielded an active area (0.43 cm2) efficiency of 13.3%. This paper also presents a discussion of the issues relating to the use of the CBD-ZnS buffer materials for improving device performance.

Kundu, Sambhu N.; Olsen, Larry C.

2005-01-03

87

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...

88

Transparent nickel selenide alloy counter electrodes for bifacial dye-sensitized solar cells exceeding 10% efficiency.  

PubMed

In the current work, we report a series of bifacial dye-sensitized solar cells (DSSCs) that provide power conversion efficiencies of more than 10% from bifacial irradiation. The device comprises an N719-sensitized TiO2 anode, a transparent nickel selenide (Ni-Se) alloy counter electrode (CE), and liquid electrolyte containing I(-)/I3(-) redox couples. Because of the high optical transparency, electron conduction ability, electrocatalytic activity of Ni-Se CEs, as well as dye illumination, electron excitation and power conversion efficiency have been remarkably enhanced. Results indicate that incident light from a transparent CE has a compensation effect to the light from the anode. The impressive efficiency along with simple preparation of the cost-effective Ni-Se alloy CEs highlights the potential application of bifacial illumination technique in robust DSSCs. PMID:25185939

Duan, Yanyan; Tang, Qunwei; He, Benlin; Li, Ru; Yu, Liangmin

2014-10-01

89

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

90

Dynamic Observation of Phase Transformation Behaviors in Indium(III) Selenide Nanowire Based Phase Change Memory.  

PubMed

Phase change random access memory (PCRAM) has been extensively investigated for its potential applications in next-generation nonvolatile memory. In this study, indium(III) selenide (In2Se3) was selected due to its high resistivity ratio and lower programming current. Au/In2Se3-nanowire/Au phase change memory devices were fabricated and measured systematically in an in situ transmission electron microscope to perform a RESET/SET process under pulsed and dc voltage swept mode, respectively. During the switching, we observed the dynamic evolution of the phase transformation process. The switching behavior resulted from crystalline/amorphous change and revealed that a long pulse width would induce the amorphous or polycrystalline state by different pulse amplitudes, supporting the improvement of the writing speed, retention, and endurance of PCRAM. PMID:25133955

Huang, Yu-Ting; Huang, Chun-Wei; Chen, Jui-Yuan; Ting, Yi-Hsin; Lu, Kuo-Chang; Chueh, Yu-Lun; Wu, Wen-Wei

2014-09-23

91

Counter electrodes from binary ruthenium selenide alloys for dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Dye-sensitized solar cell (DSSC) is a promising solution to global energy and environmental problems because of its merits on clean, cost-effectiveness, relatively high efficiency, and easy fabrication. However, the reduction of fabrication cost without sacrifice of power conversion efficiencies of the DSSCs is a golden rule for their commercialization. Here we design a new binary ruthenium selenide (Ru-Se) alloy counter electrodes (CEs) by a low-temperature hydrothermal reduction method. The electrochemical behaviors are evaluated by cyclic voltammogram, electrochemical impedance, and Tafel measurements, giving an optimized Ru/Se molar ratio of 1:1. The DSSC device with RuSe alloy CE achieves a power conversion efficiency of 7.15%, which is higher than 5.79% from Pt-only CE based DSSC. The new concept, easy process along with promising results provide a new approach for reducing cost but enhancing photovoltaic performances of DSSCs.

Li, Pinjiang; Cai, Hongyuan; Tang, Qunwei; He, Benlin; Lin, Lin

2014-12-01

92

Optoelectronic and low temperature thermoelectric studies on nanostructured thin films of silver gallium selenide  

NASA Astrophysics Data System (ADS)

Polycrystalline thin films of silver gallium selenide were deposited on ultrasonically cleaned soda lime glass substrates by multi-source vacuum co-evaporation technique. The structural analysis done by X-ray diffraction ascertained the formation of nano structured tetragonal chalcopyrite thin films. The compound formation was confirmed by X-ray photo-electron spectroscopy. Atomic force microscopic technique has been used for surface morphological analysis. Direct allowed band gap ˜1.78eV with high absorption coefficient ˜106/m was estimated from absorbance spectra. Low temperature thermoelectric effects has been investigated in the temperature range 80-330K which manifested an unusual increase in Seebeck coefficient with negligible phonon drag toward the very low and room temperature regime. The electrical resistivity of these n-type films was assessed to be ˜2.6?m and the films showed good photo response.

Jacob, Rajani; Philip, Rachel Reena; Nazer, Sheeba; Abraham, Anitha; Nair, Sinitha B.; Pradeep, B.; Urmila, K. S.; Okram, G. S.

2014-01-01

93

Simulations of silver-doped germanium-selenide glasses and their response to radiation  

PubMed Central

Chalcogenide glasses doped with silver have many applications including their use as a novel radiation sensor. In this paper, we undertake the first atomistic simulation of radiation damage and healing in silver-doped Germanium-selenide glass. We jointly employ empirical potentials and ab initio methods to create and characterize new structural models and to show that they are in accord with many experimental observations. Next, we simulate a thermal spike and track the evolution of the radiation damage and its eventual healing by application of a simulated annealing process. The silver network is strongly affected by the rearrangements, and its connectivity (and thus contribution to the electrical conductivity) change rapidly in time. The electronic structure of the material after annealing is essentially identical to that of the initial structure.

2014-01-01

94

Effect of cadmium selenide quantum dots on the dielectric and physical parameters of ferroelectric liquid crystal  

NASA Astrophysics Data System (ADS)

The effect of cadmium selenide quantum dots (CdSe QDs) on the dielectric relaxation and material constants of a ferroelectric liquid crystal (FLC) has been investigated. Along with the characteristic Goldstone mode, a new relaxation mode has been induced in the FLC material due to the presence of CdSe QDs. This new relaxation mode is strongly dependent on the concentration of CdSe QDs but is found to be independent of the external bias voltage and temperature. The material constants have also been modified remarkably due to the presence of CdSe QDs. The appearance of this new relaxation phenomenon has been attributed to the concentration dependent interaction between CdSe QDs and FLC molecules.

Singh, D. P.; Gupta, S. K.; Manohar, R.; Varia, M. C.; Kumar, S.; Kumar, A.

2014-07-01

95

Resonance enhancement of nonlinear photoluminescence in gallium selenide and related compounds  

SciTech Connect

Maker fringe experiments on the layered chalcogenide semiconductor gallium selenide (GaSe) with weak cw diode lasers are presented. It is demonstrated that nonlinear photoluminescence emitted by this material and by the similar compound GaSe{sub 0.9}S{sub 0.1} under illumination with a 632.8-nm He - Ne laser shows very strong resonance enhancement upon heating when the absorption edge and exciton levels are shifted towards the laser line. The photoluminescence appears to be strongest when the energy level of the direct exciton, which emits it, is resonant with the photon energy of the laser. The previously observed enhancement of the photoluminescence by electric fields is interpreted in this context.

Angermann, Ch; Karich, P; Kador, Lothar; Allakhverdiev, K R; Baykara, T; Salaev, E Yu

2012-05-31

96

[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

97

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

98

Transparent nickel selenide alloy counter electrodes for bifacial dye-sensitized solar cells exceeding 10% efficiency  

NASA Astrophysics Data System (ADS)

In the current work, we report a series of bifacial dye-sensitized solar cells (DSSCs) that provide power conversion efficiencies of more than 10% from bifacial irradiation. The device comprises an N719-sensitized TiO2 anode, a transparent nickel selenide (Ni-Se) alloy counter electrode (CE), and liquid electrolyte containing I-/I3- redox couples. Because of the high optical transparency, electron conduction ability, electrocatalytic activity of Ni-Se CEs, as well as dye illumination, electron excitation and power conversion efficiency have been remarkably enhanced. Results indicate that incident light from a transparent CE has a compensation effect to the light from the anode. The impressive efficiency along with simple preparation of the cost-effective Ni-Se alloy CEs highlights the potential application of bifacial illumination technique in robust DSSCs.In the current work, we report a series of bifacial dye-sensitized solar cells (DSSCs) that provide power conversion efficiencies of more than 10% from bifacial irradiation. The device comprises an N719-sensitized TiO2 anode, a transparent nickel selenide (Ni-Se) alloy counter electrode (CE), and liquid electrolyte containing I-/I3- redox couples. Because of the high optical transparency, electron conduction ability, electrocatalytic activity of Ni-Se CEs, as well as dye illumination, electron excitation and power conversion efficiency have been remarkably enhanced. Results indicate that incident light from a transparent CE has a compensation effect to the light from the anode. The impressive efficiency along with simple preparation of the cost-effective Ni-Se alloy CEs highlights the potential application of bifacial illumination technique in robust DSSCs. Electronic supplementary information (ESI) available: Schematic diagram, repeated J-V curves, CV curves of Ni0.85Se electrode at various scan rates, relationship between peak current density and square root of scan rates. See DOI: 10.1039/c4nr03900a

Duan, Yanyan; Tang, Qunwei; He, Benlin; Li, Ru; Yu, Liangmin

2014-10-01

99

Copper Data Center Database  

NSDL National Science Digital Library

The Copper Data Center Database is provided free of charge by the Copper Development Association "to increase knowledge and awareness of copper, related technologies, and the role of copper in the environment." The database is an online bibliographic search engine of literature on copper, copper alloys and copper technology dating back to 1965 and is described as covering copper technology from smelting and hydrometallurgy through the performance of copper and copper alloys in their end-use applications and service environments. Users can search by standard methods including using keywords and titles or an impressive advanced search feature is also available. Although full text listings are not available, anyone interested in related subjects will appreciate this well designed and unique tool.

Association, Copper D.

100

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

101

Chalcogenide clusters of copper and silver from silylated chalcogenide sources.  

PubMed

This review summarizes the rich structural variety of copper and silver chalcogenide clusters with protecting ligand shells of phosphane and/or organic ligands that were generated starting out from silylated chalcogenide sources. This route turned out to be fairly selective and thus allows for the isolation of uniform, polynuclear to nanosized cluster molecules that can consist of only a few or up to hundreds of metal atoms, being bridged by the chalcogen atoms. However, all of these clusters are only kinetically stable with respect to the formation of the binary coinage metal chalcogen phases, but do not collapse into the solid M(2)E materials owing to the protection by bulky ligands on the surface. Upon a more detailed analysis of the development of the structural properties with the cluster size, one recognizes differences for the particular M/E combinations: whereas copper chalcogenide and silver selenide clusters show a clear tendency to approach structural patterns of the Cu(2)E bulk, most obvious for the Cu/Se combination, this is not visible for silver sulfide clusters, even not at the largest species with 490 silver and 302 sulfur atoms. Besides the discussion on the structures of title compounds, the review presents insight into the bonding properties, reactivity, thermal and photophysical properties. The latter can be interpreted in terms of the quantum confinement effect, thus demonstrating the clusters to be understood as intermediates between mononuclear complexes and binary bulk phases. PMID:22918377

Fuhr, Olaf; Dehnen, Stefanie; Fenske, Dieter

2013-02-21

102

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

103

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.

104

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

105

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

106

Band gap engineering of zinc selenide thin films through alloying with cadmium telluride.  

PubMed

This work investigates band gap engineering of zinc selenide (ZnSe) thin films. This was achieved by mixing ZnSe with cadmium telluride (CdTe). The mass ratio (x) of CdTe in the starting material was varied in the range x = 0-0.333. The films were prepared using thermal evaporation. The chemical composition of the films was investigated through energy dispersive spectroscopy and Rutherford backscattering spectrometry. Structural analysis was carried out using X-ray diffraction and atomic force microscopy. Normal incidence transmittance and reflectance were measured over the wavelength range 300-1300 nm. The absorption coefficients and band gaps were determined from these spectrophotometric measurements. The band gap monotonically decreased from 2.58 eV (for x = 0) to 1.75 eV (for x = 0.333). Photocurrent measurements indicated that the maximum current density was obtained for films with x = 0.286. A figure of merit, based on crystallinity, band gap, and photocurrent, was defined. The optimum characteristics were obtained for the films with x = 0.231, for which the band gap was 2.14 eV. PMID:23688048

Al-Kuhaili, M F; Kayani, A; Durrani, S M A; Bakhtiari, I A; Haider, M B

2013-06-12

107

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

PubMed Central

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

108

Structural and optical characterizations of chemically deposited cadmium selenide thin films  

SciTech Connect

Highlights: {yields} CdSe thin films deposited first time using formic acid as a complexing agent. {yields} The deposited thin films were characterized by XRD, SEM, UV-vis-NIR and electrical techniques. {yields} X-ray diffraction analysis shows presence of zinc blende crystal structure. -- Abstract: Synthesis of cadmium selenide thin films by CBD method has been presented. The deposited film samples were subjected to XRD, SEM, UV-vis-NIR and TEP characterization. X-ray diffraction analysis showed that CdSe film sample crystallized in zinc blende or cubic phase structure. SEM studies reveal that the grains are spherical in shape and uniformly distributed all over the surface of the substrates. The optical band gap energy of as deposited film sample was found to be in the order of 1.8 eV. The electrical conductivity of the film sample was found to be 10{sup -6} ({Omega} cm){sup -1} with n-type of conduction mechanism.

Khomane, A.S., E-mail: ashok_khomane@rediffmail.com [Department of Chemistry, Government Rajaram College, S. U. Road, Vidyanagar, Kolhapur 416 004, Maharashtra (India)

2011-10-15

109

Memory functions of nanocrystalline cadmium selenide embedded ZrHfO high-k dielectric stack  

NASA Astrophysics Data System (ADS)

Metal-oxide-semiconductor capacitors made of the nanocrystalline cadmium selenide nc-CdSe embedded Zr-doped HfO2 high-k stack on the p-type silicon wafer have been fabricated and studied for their charge trapping, detrapping, and retention characteristics. Both holes and electrons can be trapped to the nanocrystal-embedded dielectric stack depending on the polarity of the applied gate voltage. With the same magnitude of applied gate voltage, the sample can trap more holes than electrons. A small amount of holes are loosely trapped at the nc-CdSe/high-k interface and the remaining holes are strongly trapped to the bulk nanocrystalline CdSe site. Charges trapped to the nanocrystals caused the Coulomb blockade effect in the leakage current vs. voltage curve, which is not observed in the control sample. The addition of the nanocrystals to the dielectric film changed the defect density and the physical thickness, which are reflected on the leakage current and the breakdown voltage. More than half of the originally trapped holes can be retained in the embedded nanocrystals for more than 10 yr. The nanocrystalline CdSe embedded high-k stack is a useful gate dielectric for this nonvolatile memory device.

Lin, Chi-Chou; Kuo, Yue

2014-02-01

110

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

111

Ultrafast charge- and energy-transfer dynamics in conjugated polymer: cadmium selenide nanocrystal blends.  

PubMed

Hybrid nanocrystal-polymer systems are promising candidates for photovoltaic applications, but the processes controlling charge generation are poorly understood. Here, we disentangle the energy- and charge-transfer processes occurring in a model system based on blends of cadmium selenide nanocrystals (CdSe-NC) with poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylene] (MDMO-PPV) using a combination of time-resolved absorption and luminescence measurements. The use of different capping ligands (n-butylamine, oleic acid) as well as thermal annealing allows tuning of the polymer-nanocrystal interaction. We demonstrate that energy transfer from MDMO-PPV to CdSe-NCs is the dominant exciton quenching mechanism in nonannealed blends and occurs on ultrafast time scales (<1 ps). Upon thermal annealing electron transfer becomes competitive with energy transfer, with a transfer rate of 800 fs independent of the choice of the ligand. Interestingly, we find hole transfer to be much less efficient than electron transfer and to extend over several nanoseconds. Our results emphasize the importance of tuning the organic-nanocrystal interaction to achieve efficient charge separation and highlight the unfavorable hole-transfer dynamics in these blends. PMID:24490650

Morgenstern, Frederik S F; Rao, Akshay; Böhm, Marcus L; Kist, René J P; Vaynzof, Yana; Greenham, Neil C

2014-02-25

112

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

113

Growth of zinc selenide single crystals by physical vapor transport in microgravity  

NASA Technical Reports Server (NTRS)

The goals of this research were the optimization of growth parameters for large (20 mm diameter and length) zinc selenide single crystals with low structural defect density, and the development of a 3-D numerical model for the transport rates to be expected in physical vapor transport under a given set of thermal and geometrical boundary conditions, in order to provide guidance for an advantageous conduct of the growth experiments. In the crystal growth studies, it was decided to exclusively apply the Effusive Ampoule PVT technique (EAPVT) to the growth of ZnSe. In this technique, the accumulation of transport-limiting gaseous components at the growing crystal is suppressed by continuous effusion to vacuum of part of the vapor contents. This is achieved through calibrated leaks in one of the ground joints of the ampoule. Regarding the PVT transport rates, a 3-D spectral code was modified. After introduction of the proper boundary conditions and subroutines for the composition-dependent transport properties, the code reproduced the experimentally determined transport rates for the two cases with strongest convective flux contributions to within the experimental and numerical error.

Rosenberger, Franz

1993-01-01

114

197Au Mössbauer study of copper refinery anode slimes  

NASA Astrophysics Data System (ADS)

Copper refinery anode slimes are abundantly produced during the electrolytic refining of copper. Although the slimes contain significant and economically recoverable amounts of gold and silver, the chemical state of the gold has not been fully identified. In the present work, the chemical form of gold in a copper anode, in a raw slime, and in slimes treated by different leaching procedures has been investigated by Mössbauer spectroscopy with the 77.3 keV ?-rays of197Au. The Mössbauer spectrum of the anode is typical of a dilute Au:Cu alloy. The spectrum of the raw slime consists of two components, namely, a single, rather broad line with an isomer shift (IS) of about -0.3 mm/s relative to a Pt metal source and a quadrupole doublet with an IS of + 1.2 mm/s and a quadrupole splitting of 5.0 mm/s. The single line component can be attributed to a gold-rich alloy, with an approximate composition of Au60Ag{n40} or Au80Cu20 if it is a binary alloy, or to a ternary Au-Ag-Cu alloy of appropriate composition. The parameters of the quadrupole doublet match those of Ag3AuSe2 (fischesserite) or related Ag2-xAuxSe compounds. In these compounds, the gold atoms are coordinated by two selenium atoms in a linear arrangement, as is typical for Au(I). It was found that the ratio between the concentrations of the metallic phase and the selenide strongly depends on the leaching conditions. The measurement of the Lamb-Mössbauer factor of fischesserite is also reported.

Sawicki, J. A.; Dutrizac, J. E.; Friedl, J.; Wagner, F. E.; Chen, T. T.

1993-06-01

115

Redox control of GPx catalytic activity through mediating self-assembly of Fmoc-phenylalanine selenide into switchable supramolecular architectures.  

PubMed

Artificial enzymes capable of achieving tunable catalytic activity through stimuli control of enzymatic structure transition are of significance in biosensor and biomedicine research. Herein we report a novel smart glutathione peroxidise (GPx) mimic with modulatory catalytic activity based on redox-induced supramolecular self-assembly. First, an amphiphilic Fmoc-phenylalanine-based selenide was designed and synthesized, which can self-assemble into nanospheres (NSs) in aqueous solution. The NSs demonstrate extremely low GPx activity. Upon the oxidation of hydroperoxides (ROOH), the selenide can be quickly transformed into the selenoxide form. The change of the molecular structure induces complete morphology transition of the self-assemblies from NSs to nanotubes (NTs), resulting in great enhancement in the GPx catalytic activity. Under the reduction of GSH, the selenoxide can be further reversibly reduced back into the selenide; therefore the reversible switch between the NSs and NTs can be successfully accomplished. The relationship between the catalytic activity and enzymatic structure was also investigated. The dual response nature makes this mimic play roles of both a sensor and a GPx enzyme at the same time, which can auto-detect the signal of ROOH and then auto-change its activity to achieve quick or slow/no scavenging of ROOH. The dynamic balance of ROOH is vital in organisms, in which an appropriate amount of ROOH does benefit to the metabolism, whereas surplus ROOH can cause oxidative damage of the cell instead and this smart mimic is of remarkable significance. We expect that such a mimic can be developed into an effective antioxidant drug and provide a new platform for the construction of intelligent artificial enzymes with multiple desirable properties. PMID:25366375

Huang, Zupeng; Luo, Quan; Guan, Shuwen; Gao, Jianxiong; Wang, Yongguo; Zhang, Bo; Wang, Liang; Xu, Jiayun; Dong, Zeyuan; Liu, Junqiu

2014-11-19

116

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

117

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

118

Deuterium and selenium-77 NMR study of the condensed phases of hydrogen selenide  

SciTech Connect

Hydrogen selenide has been studied by /sup 2/H and /sup 77/Se NMR between 57 and 273 K, in order to characterize the molecular motions. In solid III the molecules are essentially rigid at approx. 77 K, but there is evidence for the onset of a slow motion just before the transition to phase II. The III equivalent to II phase transition shows hysteresis. At 77 K the /sup 77/Se rigid lattice shielding tensor components were found to be sigma/sub xx/ = - 240.7, sigma/sub yy/ = -9.5, and sigma/sub zz/ = 250.2 ppm relative to sigma/sub isotropic/. The /sup 2/H line shape at 77 K indicated a quadrupole coupling constant (e/sup 2/qQ/h) = 102.6 kHz and asymmetry parameter eta = 0.113, whereas in phase II at 120 K(e/sup 2/qQ/h) = 56.9 kHz, eta = 0 and in supercooled phase II at 85 K eta = 0.059. In the plastic crystalline phase I both /sup 2/H and /sup 77/Se line shapes are completely averaged by rapid overall rotations. Apparent activation energies of 3.5 kJ mol/sup -1/ (solid I) and 3.4 kJ mol/sup -1/ (liquid) were obtained from /sup 2/H T/sub 1/ measurements, and 4.3 kJ mol/sup -1/ (solid I) and 5.7 kJ mol/sup -1/ (liquid) were obtained from /sup 77/Se T/sub 1/ measurements. The /sup 77/Se spectra show a large deuterium isotope shift of 7 ppm per deuterium, and the chemical shift also shows large discontinuities at the gas-liquid-solid I phase transitions. 45 references, 6 figures, 4 tables.

Facey, G.; Wasylishen, R.E.; Collins, M.J.; Ratcliffe, C.I.; Ripmeester, J.A.

1986-05-08

119

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

120

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

121

High adherence copper plating process  

DOEpatents

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

Nignardot, Henry (Tesuque, NM)

1993-01-01

122

Copper-containing zeolite catalysts  

DOEpatents

A catalyst useful in the conversion of nitrogen oxides or in the synthesis of nitriles or imines from amines, formed by preparing an intimate mechanical mixture of a copper (II)-containing species, such as CuO or CuCl.sub.2, or elemental copper, with a zeolite having a pore mouth comprising 10 oxygen atoms, such as ZSM-5, converting the elemental copper or copper (II) to copper (I), and driving the copper (I) into the zeolite.

Price, Geoffrey L. (Baton Rouge, LA); Kanazirev, Vladislav (Sofia, BG)

1996-01-01

123

Copper-containing zeolite catalysts  

DOEpatents

A catalyst useful in the conversion of nitrogen oxides or in the synthesis of nitriles or imines from amines, is formed by preparing an intimate mechanical mixture of a copper (II)-containing species, such as CuO or CuCl{sub 2}, or elemental copper, with a zeolite having a pore mouth comprising 10 oxygen atoms, such as ZSM-5, converting the elemental copper or copper (II) to copper (I), and driving the copper (I) into the zeolite.

Price, G.L.; Kanazirev, V.

1996-12-10

124

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

125

Reduction of Selenate to Selenide by Sulfate-Respiring Bacteria: Experiments with Cell Suspensions and Estuarine Sediments  

PubMed Central

Washed cell suspensions 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 quantities 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. PMID:16347366

Zehr, Jonathan P.; Oremland, Ronald S.

1987-01-01

126

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...

127

Copper corrosion issue and analysis on copper damascene process  

Microsoft Academic Search

As semiconductor device features shrink into deep-submicron regime, copper metallization is taking the place of aluminum (Al)-tungsten (W) metallization because of the higher electrical conductivity and electromigration resistance of copper. However, it is very difficult for copper to be etched by dry etching method, thus copper metallization is created with damascene process. In this process, chemical mechanical polishing (CMP) is

Zhigang Song; Soh Ping Neo; Chong Khiam Oh; Shailesh Redkar; Yuan-Ping Lee

2005-01-01

128

Fabricating Copper Nanotubes by Electrodeposition  

NASA Technical Reports Server (NTRS)

Copper tubes having diameters between about 100 and about 200 nm have been fabricated by electrodeposition of copper into the pores of alumina nanopore membranes. Copper nanotubes are under consideration as alternatives to copper nanorods and nanowires for applications involving thermal and/or electrical contacts, wherein the greater specific areas of nanotubes could afford lower effective thermal and/or electrical resistivities. Heretofore, copper nanorods and nanowires have been fabricated by a combination of electrodeposition and a conventional expensive lithographic process. The present electrodeposition-based process for fabricating copper nanotubes costs less and enables production of copper nanotubes at greater rate.

Yang, E. H.; Ramsey, Christopher; Bae, Youngsam; Choi, Daniel

2009-01-01

129

Synthesis and characterization of cadmium selenide nanostructures on porous aluminum oxide templates by high frequency alternating current electrolysis  

NASA Astrophysics Data System (ADS)

We have successfully deposited nanostructured cadmium selenide (CdSe) inside anodic aluminum oxide (AAO) templates from aqueous electrolyte containing cadmium sulfate, selenium oxide and mercuric chloride by using high frequency alternating current (19 V rms, 200 Hz). Addition of mercury ions aids in the deposition of CdSe inside anodic oxide pores. Scanning and transmission electron microscopy studies of the deposit etched in phosphoric acid showed the presence of end standing nanostrips. Energy dispersive X-ray analysis of the deposit confirmed the presence of cadmium and selenium in the deposit. X-ray diffraction (XRD) studies of the deposit showed small but broad diffraction peaks consistent with the presence of hexagonal CdSe. Optical studies revealed blue shift in band gap energy due to quantum confinement.

Sankar, P. Ram; Tiwari, Pragya; Kumar, Ravi; Ganguli, Tapas; Mukherjee, C.; Srivastava, A. K.; Oak, S. M.; Pathak, Rajesh K.

130

Synthesis and characterization of the layered iron-selenide Na0.8Fe1.6Se2  

NASA Astrophysics Data System (ADS)

An iron-selenide Na0.8Fe1.6Se2 single crystal has been successfully synthesized using a self-flux method. The electrical resistivity measurement shows that this material exhibits semiconducting behavior in the whole temperature range, with an anomalous increment of resistivity at Ts˜595 K. By varying the concentrations of Na and Fe, a small volume of superconducting phase could be achieved with a critical temperature of Tc˜34 K. Structural characterization shows that, similarly to K0.8Fe1.6Se2 , the Na0.8Fe1.6Se2 phase exhibits clear superstructure with a modulation wave vector of q =(3 /5 ,1 /5 ,0 ) caused by the Fe-vacancy order within the a-b plane.

Long, Y. J.; Wang, D. M.; Wang, Z.; Yang, H. X.; He, J. B.; Zhao, L. X.; Wang, P. P.; Xue, M. Q.; Li, J. Q.; Ren, Z. A.; Chen, G. F.

2014-10-01

131

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

132

The role of surface defects in multi-exciton generation of lead selenide and silicon semiconductor quantum dots.  

PubMed

Multi-exciton generation (MEG), the creation of more than one electron-hole pair per photon absorbed, occurs for excitation energies greater than twice the bandgap (E(g)). Imperfections on the surface of quantum dots, in the form of atomic vacancies or incomplete surface passivation, lead to less than ideal efficiencies for MEG in semiconductor quantum dots. The energetic onset for MEG is computed with and without surface defects for nanocrystals, Pb(4)Se(4), Si(7), and Si(7)H(2). Modeling the correlated motion of two electrons across the bandgap requires a theoretical approach that incorporates many-body effects, such as post-Hartree-Fock quantum chemical methods. We use symmetry-adapted cluster with configuration interaction to study the excited states of nanocrystals and to determine the energetic threshold of MEG. Under laboratory conditions, lead selenide nanocrystals produce multi-excitons at excitation energies of 3 E(g), which is attributed to the large dielectric constant, small Coulomb interaction, and surface defects. In the absence of surface defects the MEG threshold is computed to be 2.6 E(g). For lead selenide nanocrystals with non-bonding selenium valence electrons, Pb(3)Se(4), the MEG threshold increases to 2.9 E(g). Experimental evidence of MEG in passivated silicon quantum dots places the onset of MEG at 2.4 E(g). Our calculations show that the lowest multi-exciton state has an excitation energy of 2.5 E(g), and surface passivation enhances the optical activity of MEG. However, incomplete surface passivation resulting in a neutral radical on the surface drives the MEG threshold to 4.4 E(g). Investigating the mechanism of MEG at the atomistic level provides explanations for experimental discrepancies and suggests ideal materials for photovoltaic conversion. PMID:22360209

Jaeger, Heather M; Fischer, Sean; Prezhdo, Oleg V

2012-02-14

133

Cell Biology of Copper  

Microsoft Academic Search

\\u000a The transition metal, copper (Cu), is an essential micronutrient for normal plant growth and development. Copper is a cofactor\\u000a of proteins involved in photosynthesis, respiration, ethylene perception, removal of superoxide radicals, and cell wall modification.\\u000a The biochemical reactions catalyzed by most Cu enzymes in plants are known. However, in many cases we are not yet sure about\\u000a the biological function

Christopher M. Cohu; Marinus Pilon

134

Drinking Water Problems: Copper  

E-print Network

management strategy, consider treating your water or seeking an alternative drink- ing-water supply such as bottled water. Treatment options for reducing copper concentrations in water include (1) reverse osmosis, (2) distillation or (3) ion exchange. Reverse... management strategy, consider treating your water or seeking an alternative drink- ing-water supply such as bottled water. Treatment options for reducing copper concentrations in water include (1) reverse osmosis, (2) distillation or (3) ion exchange. Reverse...

Dozier, Monty; McFarland, Mark L.; Lesikar, Bruce J.

2006-01-25

135

Copper deficiency myelopathy.  

PubMed

Acquired copper deficiency has been recognised as a rare cause of anaemia and neutropenia for over half a century. Copper deficiency myelopathy (CDM) was only described within the last decade, and represents a treatable cause of non-compressive myelopathy which closely mimics subacute combined degeneration due to vitamin B12 deficiency. Here, 55 case reports from the literature are reviewed regarding their demographics, aetiology, haematological and biochemical parameters, spinal imaging, treatment and outcome. The pathophysiology of disorders of copper metabolism is discussed. CDM most frequently presented in the fifth and sixth decades and was more common in women (F:M = 3.6:1). Risk factors included previous upper gastrointestinal surgery, zinc overload and malabsorption syndromes, all of which impair copper absorption in the upper gastrointestinal tract. No aetiology was established in 20% of cases. High zinc levels were detected in some cases not considered to have primary zinc overload, and in this situation the contribution of zinc to the copper deficiency state remained unclear. Cytopenias were found in 78%, particularly anaemia, and a myelodysplastic syndrome may have been falsely diagnosed in the past. Spinal MRI was abnormal in 47% and usually showed high T2 signal in the posterior cervical and thoracic cord. In a clinically compatible case, CDM may be suggested by the presence of one or more risk factors and/or cytopenias. Low serum copper and caeruloplasmin levels confirmed the diagnosis and, in contrast to Wilson's disease, urinary copper levels were typically low. Treatment comprised copper supplementation and modification of any risk factors, and led to haematological normalisation and neurological improvement or stabilisation. Since any neurological recovery was partial and case numbers of CDM will continue to rise with the growing use of bariatric gastrointestinal surgery, clinical vigilance will remain the key to minimising neurological sequelae. Recommendations for treatment and prevention are made. PMID:20232210

Jaiser, Stephan R; Winston, Gavin P

2010-06-01

136

Anodic electrosynthesis of cadmium selenide thin films; Characterization and comparison with the passive/transpassive behavior of CdX (X = S,Te) counterpart  

SciTech Connect

This paper reports on cadmium selenide thin films electrosynthesized by an anodic route employing alkaline selenide solutions. The thermodynamic aspects of the electrodeposition chemistry were first explored via Pourbaix diagrams; the kinetic aspects were studied by linear sweep voltammetry on a Cd anode. The photoaction spectra of these anodic thin films revealed an optical gap energy (1.7 eV) in good agreement with the value known for CdSe. Their luminescence response, however, suggested a high density of carrier recombination centers located {approximately}0.2 eV below the conduction band. X-ray photoelectron spectroscopy revealed that the anodic thin films were stoichiometric in composition. In situ examination of the material during thin film growth by cyclic photovoltammetry revealed anodic photoeffects at potentials just past the Cd corrosion wave. The growth kinetics in the passive region adhered to a direct logarithmic rate law, while a diffusion mechanism was seen to prevail in the transpassive regime.

Ham, D.; Mishra, K.K.; Rajeshwar, K. (Dept. of Chemistry, Univ. of Texas at Arlington, Arlington, TX (US))

1991-01-01

137

Three-dimensional electrons and two-dimensional electric subbands in the transport properties of tin-doped n-type indium selenide: Polar and homopolar phonon scattering  

Microsoft Academic Search

Electron-scattering mechanisms in n-type indium selenide doped with different amounts of tin are studied by means of the Hall effect (30-300 K) and photo-Hall effect (300 K). The electron mobility at room temperature is found to increase with the free-electron concentration in samples with low tin content. The same behavior is observed when the electron concentration increases due to thermal

A. Segura; B. Mar; J. Martinez-Pastor; A. Chevy

1991-01-01

138

Tuning the Optical Properties of Nanoscale Materials on Surfaces Through Controlled Exchange Reactions on Cadmium Selenide Quantum Dots and Patterning of Gold and QD Nanoparticle Arrays  

E-print Network

TUNING THE OPTICAL PROPERTIES OF NANOSCALE MATERIALS ON SURFACES THROUGH CONTROLLED EXCHANGE REACTIONS ON CADMIUM SELENIDE QUANTUM DOTS AND PATTERNING OF GOLD AND QD NANOPARTICLE ARRAYS A Dissertation by ARIKA PRAVITASARI Submitted... Jaime Grunlan Head of Department, David H. Russell December 2013 Major Subject: Chemistry Copyright 2013 Arika Pravitasari ii ABSTRACT This work focused on the integration of CdSe quantum dots (QDs) and Au nanoparticles (NPs...

Pravitasari, Arika

2013-11-11

139

Copper and copper-nickel alloys as zebra mussel antifoulants  

SciTech Connect

Copper has been used in the marine environment for decades as cladding on ships and pipes to prevent biofouling by marine mussels (Mytilus edulis L.). This motivated the present investigation into the possibility of using copper to prevent biofouling in freshwater by both zebra mussels and quagga mussels (Dreissena polymorpha and D. bugensis collectively referred to as zebra mussels). Copper and copper alloy sheet proved to be highly effective in preventing biofouling by zebra mussels over a three-year period. Further studies were conducted with copper and copper-nickel mesh (lattice of expanded metal) and screen (woven wire with a smaller hole size), which reduced the amount of copper used. Copper screen was also found to be strongly biofouling-resistant with respect to zebra mussels, while copper mesh reduced zebra mussel biofouling in comparison to controls, but did not prevent it entirely. Preliminary investigations into the mechanism of copper antifouling, using galvanic couples, indicated that the release of copper ions from the surface of the exposed metal into the surrounding water is directly or indirectly responsible for the biofouling resistance of copper.

Dormon, J.M.; Cottrell, C.M.; Allen, D.G.; Ackerman, J.D.; Spelt, J.K. [Univ. of Toronto, Ontario (Canada)

1996-04-01

140

Copper alloys for industrial hardware  

SciTech Connect

Copper and its alloys are widely used because of their excellent electrical and thermal conductivities, outstanding resistance to corrosion, and ease of fabrication. Lifecycle costs are another important reason for new and expanding applications for copper and copper alloys. For example, lifecycle cost analyses favor the use of copper-nickel for automotive brake tubes, and copper alloys in molds for plastic parts. However, copper also competes very well on a first-cost basis in the brazed copper-and-brass radiator, and in free-cutting brass machined components. This article highlights four specific applications in which advanced copper alloys and fabrication techniques enhance the performance of industrial hardware, based largely on conductivity, corrosion resistance, and lifecycle costs.

Peters, D.T. [Copper Development Association Inc., New York, NY (United States)

1996-10-01

141

The mineralogy of copper electrorefining  

NASA Astrophysics Data System (ADS)

The impurities in copper anodes occur both in solid solution in the copper metal matrix and in discrete inclusions at the copper grain boundaries. During electrorefining, all the impurities undergo extensive chemical and/or morphological changes. These changes impact significantly on anode passivation, cathode quality, electrolyte purification and, of course, the subsequent recovery of by-products from the anode slimes. Recently, mineralogical studies have been undertaken to characterize the various impurities and elucidate their transformations during copper electrorefining.

Chen, T. T.; Dutrizac, J. E.

1990-08-01

142

High adherence copper plating process  

SciTech Connect

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

Mignardot, H.

1992-12-31

143

SOURCES OF COPPER AIR EMISSIONS  

EPA Science Inventory

The report gives results of a study to update estimates of atmospheric emissions of copper and copper compounds in the U.S. Source categories evaluated included: metallic minerals, primary copper smelters, iron and steel making, combustion, municipal incineration, secondary coppe...

144

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

145

Migration of copper and some other metals from copper tableware  

SciTech Connect

Intake of heavy metals is an important problem in human health. Certain heavy metals are avoided with regard to their use for utensils or tableware coming into contact with food, although copper is widely used in food processing factories or at home. The use of copper products for the processing, cooking or serving of foods and beverages is considered to be a cause of a copper contamination. Although copper is essential element, its excess ingestion is undesirable. In this study, the migration of copper from tin-plated or non-plated copperware under several experimental conditions was investigated using food-simulating solvents.

Ishiwata, H.; Inoue, T.; Yoshihira, K.

1986-11-01

146

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

147

Earth's anthrobiogeochemical copper cycle  

Microsoft Academic Search

An “anthrobiogeochemical” copper cycle, from Earth's core to the Moon, combining natural biogeochemical and human anthropogenic stocks and flows is derived for the mid-1990s. Although some aspects of the quantification have moderate to high uncertainty, the anthropogenic mining, manufacturing, and use flows (on the order of 104 Gg Cu\\/yr) clearly dominate the cycle. In contrast, the natural repositories of Earth's

J. N. Rauch; T. E. Graedel

2007-01-01

148

Hydrogen Transport in Copper  

SciTech Connect

Hydrogen interaction with oxygen in copper exerts a significant influence on the apparent hydrogen diffusivity and the quantity of hydrogen absorbed. Correlation of the amount of absorbed tritium with oxygen content and dependence of permeation transients on both oxygen content and prior treatment indicate that both reversible and irreversible interactions occur between hydrogen and dissolved oxygen. This paper discusses results of that study.

Caskey, G.R. Jr.

2001-10-23

149

Presenilin Promotes Dietary Copper Uptake  

PubMed Central

Dietary copper is essential for multicellular organisms. Copper is redox active and required as a cofactor for enzymes such as the antioxidant Superoxide Dismutase 1 (SOD1). Copper dyshomeostasis has been implicated in Alzheimer’s disease. Mutations in the presenilin genes encoding PS1 and PS2 are major causes of early-onset familial Alzheimer’s disease. PS1 and PS2 are required for efficient copper uptake in mammalian systems. Here we demonstrate a conserved role for presenilin in dietary copper uptake in the fly Drosophila melanogaster. Ubiquitous RNA interference-mediated knockdown of the single Drosophila presenilin (PSN) gene is lethal. However, PSN knockdown in the midgut produces viable flies. These flies have reduced copper levels and are more tolerant to excess dietary copper. Expression of a copper-responsive EYFP construct was also lower in the midgut of these larvae, indicative of reduced dietary copper uptake. SOD activity was reduced by midgut PSN knockdown, and these flies were sensitive to the superoxide-inducing chemical paraquat. These data support presenilin being needed for dietary copper uptake in the gut and so impacting on SOD activity and tolerance to oxidative stress. These results are consistent with previous studies of mammalian presenilins, supporting a conserved role for these proteins in mediating copper uptake. PMID:23667524

Southon, Adam; Greenough, Mark A.; Ganio, George; Bush, Ashley I.; Burke, Richard; Camakaris, James

2013-01-01

150

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. PMID:24762534

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

2014-01-01

151

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

152

Electric double-layer transistor using layered iron selenide Mott insulator TlFe1.6Se2  

PubMed Central

A1–xFe2–ySe2 (A = K, Cs, Rb, Tl) are recently discovered iron-based superconductors with critical temperatures (Tc) ranging up to 32 K. Their parent phases have unique properties compared with other iron-based superconductors; e.g., their crystal structures include ordered Fe vacancies, their normal states are antiferromagnetic (AFM) insulating phases, and they have extremely high Néel transition temperatures. However, control of carrier doping into the parent AFM insulators has been difficult due to their intrinsic phase separation. Here, we fabricated an Fe-vacancy-ordered TlFe1.6Se2 insulating epitaxial film with an atomically flat surface and examined its electrostatic carrier doping using an electric double-layer transistor (EDLT) structure with an ionic liquid gate. The positive gate voltage gave a conductance modulation of three orders of magnitude at 25 K, and further induced and manipulated a phase transition; i.e., delocalized carrier generation by electrostatic doping is the origin of the phase transition. This is the first demonstration, to the authors' knowledge, of an EDLT using a Mott insulator iron selenide channel and opens a way to explore high Tc superconductivity in iron-based layered materials, where carrier doping by conventional chemical means is difficult. PMID:24591598

Katase, Takayoshi; Hiramatsu, Hidenori; Kamiya, Toshio; Hosono, Hideo

2014-01-01

153

Thermo-optical effect in zinc selenide windows for two-color interferometer for fusion plasma diagnostics  

SciTech Connect

After some improvements in the two-color interferometer for plasma density measurements in the TJII fusion device, an effect, which we attribute to the thermo-optical characteristics of zinc selenide windows, has been put in evidence. Part of the 53.2 GHz mm radiation, used to heat the plasma, heats the windows and produces an optical path length difference between the two laser beams of 10.6 and 0.633 {mu}m wavelength. The effect induces a deformation of the line integral density measured by the interferometer. It is important in shots with high plasma reflectivity at the electron cyclotron resonance heating (ECRH) frequency. Some experiments and calculations have been done. The effect is explained and its order of magnitude is justified on the basis of some approximations. Several ways to avoid the effect including a correction procedure are discussed. Other possible heating sources are also discussed. The observed effect could be very relevant for experiments where ECRH is the main heating mechanism.

Sanchez, Miguel; Sanchez, Joaquin [Dena Laser S.L., 28035 Madrid (Spain); Asociacion EURATOM/CIEMAT, 28040 Madrid (Spain)

2005-04-01

154

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

155

A new mixed group 5 metal selenide, Nb1.41V0.59Se9  

PubMed Central

The new mixed-metallic phase, niobium vanadium nona­selenide, (Nb2-xVx)Se9 (0.18? x ? 0.59) is isostructural with monoclinic V2Se9. The structure is composed of chains of bicapped trigonal–prismatic [MSe8] units. The metal (M) site is occupied by statistically disordered Nb [0.706?(5)] and V [0.294?(5)] atoms. Two trigonal prisms are linked by sharing a recta­ngular face composed of two Se2 2? pairs. Through three edging and capping Se atoms, the chains are extended along [101]. The chain shows alternating short [2.8847?(7)?Å] and long [3.7159?(7)?Å] M—M distances. The structure shows a wide range of Se—Se inter­actions. In addition to the Se2 2? pairs of the recta­ngular face, an inter­mediate Se?Se separation [2.6584?(5)?Å] is found. The amount of each metal can vary, [(Nb2-xVx)Se9, 0.18 ? x ?m 0.59] and they seem to form a random substitutional solid solution. The M—M distances increase gradually by increasing the amount of Nb atoms. The classical charge-balance of the compound can be described as [M 4+]2[Se2 2?]2[Se5 4?]. PMID:22064790

Lee, Eunsil; Yun, Hoseop

2011-01-01

156

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

2014-07-01

157

Role of copper in IUDs.  

PubMed

This report analyzes the contraceptive potential of copper IUDs. The antifertility action of copper in IUDs is considered to involve 1) inhibition of zinc-containing metalloenzymes in the uterus, 2) reduced activity in the endometrial steroid receptor, 3) production of low levels of human chorionic gonadotropin in the luteal phase, 4) depression of ovum transport through the uterine tubes and inhibition of the penetration of cervical mucus by sperm, 5) elevation of the fibrinoloytic activity of the endometrium, and 6) depression of the synthesis of prostaglandins. These biochemical and physiological changes in response to copper released from the IUD are thought to cause only a local effect and systemic accumulation of copper from the device is considered unlikely. The rate of release of copper varies during the time the device remains in the uterus, declining exponentially during the 1st 2 years of use and then increasing as a result of destabilization and fragmentation of the accumulated layer of copper corrosion products. Accelerated copper loss is associated with menorrhagis, higher parity, and the presence of a cervical lesion at the time of IUD insertion. However, accelerated loss of the copper coil does not seem to cause either copper toxicity or decreased contraceptive efficiency. Women with insulin-dependent diabetes may manifest a different copper corrosion process and possibly a higher incidence of contraceptive failure. Since copper IUDs must be replaced more often than inert devices, there is a risk of increased incidence of pelvic inflammatory disease, reported to occur more frequently after replacement of an IUD. The longterm retention of copper IUDs probably has the same risk of infection as that associated with inert devices, and there is no evidence to link the presence of copper with any bacteriostatic or bactericidal action in vivo. The probability of fragmentation is reduced by new types of devices in which the copper wire is replaced by copper bands or a core of an inert metal is included inside the copper wire. It is concluded that copper IUDs, especially the newer devices with a more stable copper component, provide a successful fertility control method. PMID:12266319

Chantler, E N

1984-08-01

158

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

159

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. PMID:23009710

2012-01-01

160

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

161

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. PMID:20964417

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

2013-01-01

162

Polarizability of neutral copper clusters.  

PubMed

Neutral copper clusters are characterized through their molecular structures, binding energy and electric dipole polarizability. It is shown that the mean and anisotropy of polarizability tensor are useful properties in the characterization and rationalization of reactivity and growth patterns in copper clusters. We also found a relationship between softness per atom and cubic root polarizability per atom which can be useful to get global softness in copper clusters. PMID:25149439

Jaque, Pablo; Toro-Labbé, Alejandro

2014-09-01

163

Hydroxyapatite interactions with copper complexes  

Microsoft Academic Search

Hydroxyapatite was used to remove dilute copper(II) from aqueous solutions containing organic ligands. Both synthetic apatite and natural apatite originating from animal bones retained copper(II) in a flow-through column experiment but lost much of this ability when glycine, ethylenediamine or ethylenediaminetetraacetic acid (EDTA) was present in the solution. The amounts of copper(II) withheld by apatite was compared to the concentrations

F. Fernane; M. O. Mecherri; P. Sharrock; M. Fiallo; R. Sipos

2010-01-01

164

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

Microsoft Academic Search

A new organically templated indium selenide, [C6H16N2][In2Se3(Se2)], 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

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

2011-01-01

165

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

166

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

167

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

168

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. PMID:21735378

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

2011-01-01

169

Lead and Copper Control 101  

EPA Science Inventory

This presentation is an overview of the most important water treatment strategies for the control of lead and copper release from drinking water corrosion. In addition to the sections specifically on lead and copper treatment, sections are included that cover sampling to find le...

170

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

171

2-Pyridyl selenolates of antimony and bismuth: Synthesis, characterization, structures and their use as single source molecular precursor for the preparation of metal selenide nanostructures and thin films.  

PubMed

Reactions of SbCl(3) and BiCl(3) with M'Se-C(5)H(3)(R-3)N (M' = Li or Na; R = H or Me) gave homoleptic selenolate complexes of the general formula [M{Se-C(5)H(3)(R-3)N}(3)] (M = Sb or Bi). The complexes were characterized by elemental analysis, UV-vis and NMR ((1)H, (13)C and (77)Se) spectroscopy. The single crystal X-ray analysis of [M{Se-C(5)H(3)(Me-3)N}(3)].nH(2)O (M/n = Sb/1.5 and Bi/0.5) revealed that the antimony complex adopts a trigonal pyramidal configuration with monodentate selenolate ligands while the bismuth analogue acquires a distorted square pyramidal configuration defined by two chelating and one monodentate selenolate groups. Pyrolysis of [M{Se-C(5)H(3)(Me-3)N}(3)] either in a furnace or in hexadecylamine (HDA) at different temperatures gave a variety of M(2)Se(3) nanostructures. Thin films of metal selenides have also been deposited on glass substrate by aerosol-assisted chemical vapor deposition (AACVD). Both nanostructures and thin films of metal selenides were characterized by UV-vis spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM). PMID:20714620

Sharma, Rakesh K; Kedarnath, G; Jain, Vimal K; Wadawale, Amey; Nalliath, Manoj; Pillai, C G S; Vishwanadh, B

2010-10-01

172

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

173

Detecting and Sorting Disseminated Native Copper Ores.  

National Technical Information Service (NTIS)

The report describes and evaluates a detector-sorting device to separate copper-bearing and non-copper-bearing rock in native Cu ore. Results of small-scale sorting tests on four Michigan native copper samples showed 60 to 85 pct of the copper was recover...

V. R. Miller, R. W. Nash, A. E. Schwaneke

1974-01-01

174

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

175

Selecting copper and copper alloys; Part 2: Cast products  

SciTech Connect

This article provides an introduction to the properties, characteristics, and applications of cast coppers and copper alloys. An overview of alloy families is presented since it is impractical to describe all 130 standard grades in detail. However, additional technical information is readily available from the Copper Development Assn. Inc. (CDA) and the resources listed in the references and bibliography at the end of the article. Copper casting alloys are primarily selected for either their corrosion resistance, or their combination of corrosion resistance and mechanical properties. The materials also feature good castability, high machinability, and, compared with other corrosion-resistant alloys, reasonable cost. Additional benefits include biofouling resistance--important in marine applications--and a spectrum of attractive colors. Many of the alloys also have favorable tribological properties, which explains their widespread use for sleeve bearings, wear plates, gears, and other wear-prone components.

Peters, D.T. (Copper Development Association Inc., New York, NY (United States)); Kundig, K.J.A. (Kundig (Konrad J.A.), Randolph, NJ (United States))

1994-06-01

176

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

177

Accelerated testing of copper corrosion  

SciTech Connect

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. Initial work successfully reproduced soft-water copper pitting in the laboratory using a synthetic water, facilitating future studies of pit initiation and potential remedies. Relative pitting tendencies were predicted using the short-term test, as was the long-term release of the by-products of copper corrosion. Pitting severity increased with increasing pH and duration of stagnation and decreased in the presence of natural organic matter or chlorine residuals.

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)

1993-10-01

178

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

179

Recent advances in copper radiopharmaceuticals.  

PubMed

Copper has five radioisotopes ((60)Cu, (61)Cu, (62)Cu, (64)Cu, and (67)Cu) that can be used in copper radiopharmaceuticals. These radioisotopes decay by mixed emissions of ?+, ?-, and ? with a wide range of half-lives from 9.74 min ((62)Cu) to 2.58 d ((67)Cu), which enable the design and synthesis of a variety of radiopharmaceuticals for different biomedical applications in diagnostic and therapeutic nuclear medicine. However, due to the availability and production cost, the research efforts in copper radiopharmaceuticals are mainly focused on the use of (64)Cu (t(1/2) = 12.7 h; 17.4% ?+, 43% EC, 39% ?-), a radioisotope with low positron energy (E ?+max = 0.656 MeV) that is ideal for positron emission tomography (PET) imaging quantification and ?- emissions along with Auger electron for radiotherapy. Driven by the ever-increasing availability of preclinical and clinical PET scanners, a considerable interest has been seen in the development of novel copper radiopharmaceuticals in the past decade for a variety of diseases as represented by PET imaging of cancer. To avoid unnecessary literature redundancy, this review focuses on the unrepresented research aspects of copper chemistry (e.g. electrochemistry) and their uses in the evaluation of novel nuclear imaging probe design and recent advances in the field towards the practical use of copper radiopharmaceuticals. PMID:22191650

Hao, Guiyang; Singh, Ajay N; Oz, Orhan K; Sun, Xiankai

2011-04-01

180

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 DEMONSTRATOR will utilize 76Ge from Russia, but for the Tonne-Scale experiment it is hoped that an alternate technology 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. The MAJORANA DEMONSTRATOR is a DOE and NSF funded project with a major science impact. 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 these 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 for isotopic analysis as a test of the NID technology. The results of that analysis are reported here.

Kouzes, Richard T.; Zhu, Zihua

2011-02-01

181

Copper-zinc superoxide dismutase and intracellular copper incorporation  

SciTech Connect

Copper deficient chicken aortas were grown in culture to study the metal-dependent mechanism for restoring CuZnSOD activity and delivering copper to the cell. Intracellular incorporation of copper was detected by measuring the activity of CuZnSOD and/or incorporation of radioactive copper into CuZnSOD. Cultures supplemented with CuCl/sub 2/, albumin-Cu, or ceruloplasmin required 24 h and 0.3 ug Cu/ml medium to fully restore the enzyme. Activation did not occur at 4/sup 0/C or with Cu-EDTA as the supplement. Mn/sup +2/, Zn/sup +2/ alone or in combination, did not activate or enhance the activation achieved by CuCl/sub 2/. Cordycepin and cycloheximide added to the medium did not inhibit the activation, supporting the suggestion that copper is activating an apoCuZnSOD. /sup 67/Cu-labeled albumin and ceruloplasmin added to the culture were able to incorporate /sup 67/Cu into CuZnSOD, as detected by immunoprecipitation of CuZnSOD.

Dameron, C.T.

1987-01-01

182

Interdiffusion in Lead Selenide.  

National Technical Information Service (NTIS)

A theoretical model was developed to explain the movement of a p-n junction in PbSe by the interdiffusion process. This model, which is a modification of an interdiffusion theory due to Brebrick, has one value for the diffusion coefficient in p-type mater...

R. W. Brodersen, J. N. Walpole, A. R. Calawa

1969-01-01

183

[Copper - a major contraceptive agent?].  

PubMed

The effect of copper ions on the motility of human sperm was studied in vitro to determine whether copper is toxic to sperm. Sperm samples from 30 men of proven fertility who had high quality sperm were collected, separated from the seminal fluid, and resuspended in Menezzo, a chemical medium designed to resemble the secretions of the Fallopian tubes. Menezzo contains all the known constituents which aid sperm capacitation, including mineral salts, organic compounds, free amino acids, and enzymes. Its pH is between 7.4 and 7.6. After 1 hour of incubation the dead and weak sperm were separated out and only mobile sperm were tested. Crystallized copper sulfate was added to 4 of the 5 sperm-Menezzo mixtures. The final concentrations were of 1 millimolar, .1 millimolar, .01 millimolar, and .001 millimolar. Sperm motility showed a statistically significant decrease in the concentration of 1 millimolar but only after a latency period of at least 5 hours. At lesser concentrations and in shorter time periods no significant difference was observed compared to the control. The copper released from a copper IUD into the uterine fluid does not exceed a concentration of .1 millimolar. The lower concentration and the long latency period before the toxic effect manifests itself, seem to indicate that copper has no direct contraceptive effect. Copper is however known to promote inflammatory reactions, and it may work in vivo through the intermediacy of the leukocytes in the uterine cavity, either by directly stimulating phagocytosis or by release of substances toxic to sperm. PMID:12280892

Leroy-martin, B; Saint-pol, P; Hermand, E

1987-06-01

184

Reliability of copper interconnects in integrated circuits  

E-print Network

As dimensions shrink and current densities increase, the reliability of metal interconnects becomes a serious concern. In copper interconnects, the dominant diffusion path is along the interface between the copper and the ...

Choi, Zung-Sun

2007-01-01

185

Placental copper transport in the brindled mouse  

SciTech Connect

Pregnant brindled (brin) mice were injected at 16 or 19 days gestation with 2 doses of CuCl/sub 2/ 6 mcg/g/dose, separated by 12 h, and sacrificed 6 h after the second. The copper conc. in placenta (P) and kidneys (K) of uninjected (UI) brin mice were higher than in UI controls, while conc. in liver (L) and fetal carcass (F) were lower. After injection (I), placental copper conc. increased while the carcass conc. remained unchanged. Brin mouse is a model for the human inborn error of copper metabolism, Menkes syndrome, which is characterized by signs of copper deficiency. These data indicate that metabolism of copper in brin fetus is abnormal, but depressed fetal copper levels cannot be corrected by acute copper dosing because of the sequestration of copper in placenta.

Garnica, A.; Bates, J.

1986-03-01

186

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

187

Tensile behavior of nanocrystalline copper  

SciTech Connect

High density nanocrystalline copper produced by inert gas condensation was tested in tension. Displacements were measured using foil strain gauges, which greatly improved the accuracy of the strain data. The Young`s modulus of nanocrystalline copper was found to be consistent with that of coarse-grained copper. Total elongations of {approx} 1% were observed in samples with grain sizes less than 50 nm, while a sample with a grain size of 110 nm exhibited more than 10% elongation, perhaps signifying a change to a dislocation-based deformation mechanism in the larger-grained material. In addition, tensile tests were performed as a function of strain rate, with a possible trend of decreased strength and increased elongation as the strain rate was decreased.

Sanders, P.G.; Weertman, J.R. [Northwestern Univ., Evanston, IL (United States). Dept. of Materials Science and Engineering; Eastman, J.A. [Northwestern Univ., Evanston, IL (United States). Dept. of Materials Science and Engineering]|[Argonne National Lab., IL (United States). Materials Science Div.

1995-11-01

188

Copper and Anesthesia: Clinical Relevance and Management of Copper Related Disorders  

PubMed Central

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

189

Hydrogen damage in friction welded copper joints  

Microsoft Academic Search

The occurrence of hydrogen attack in electrolytic copper and in copper deoxidized with phosphorous, during model heating in oil and in friction welded specimens was investigated. Dissimilar-metal joints, i.e. copper\\/TZM (titanium–zirconium–molybdenum based alloy) joints and copper\\/austenitic steel joints, were subjected to microstructural examinations and tensile strength tests.Microcracks near the weld surface, caused by hydrogen attack, were found to occur in

Andrzej Ambroziak

2010-01-01

190

Textured carbon surfaces on copper by sputtering  

NASA Technical Reports Server (NTRS)

A very thin layer of highly textured carbon is applied to a copper surface by a triode sputtering process. A carbon target and a copper substrate are simultaneously exposed to an argon plasma in a vacuum chamber. The resulting carbon surface is characterized by a dense, random array of needle like spires or peaks which extend perpendicularly from the copper surface. The coated copper is especially useful for electrode plates in multistage depressed collectors.

Curren, A. N. (inventor); Jensen, K. A. (inventor); Roman, R. F. (inventor)

1986-01-01

191

Copper content in foods of Java Island and estimation of daily copper intake  

SciTech Connect

The purpose of this study was first to determine copper content in soil, foodstuff and feces of villagers, and estimate the daily copper intake of the villagers and a guest. The data obtained may help clarify the relationships of copper content in the soil-plant (food)-daily intake-feces in Indonesia. Secondly, the percentage of copper contribution of food groups was calculated to determine the influence of the food patterns of villagers and a guest on daily copper intake. Finally, evaluation was made of daily copper intake of villagers in terms of estimated daily copper requirement by WHO.

Rivai, I.F.; Suzuki, S.; Koyama, H.; Hyodo, K.; Djuangsih, N.; Soemarwoto, O.

1988-07-01

192

Copper(I)-?-Ketocarboxylate Complexes  

PubMed Central

A series of copper(I)-?-ketocarboxylate complexes have been prepared and shown to exhibit variable coordination modes of the ?-ketocarboxylate ligand. Reaction with O2 induces decarboxylation of this ligand and the derived copper-oxygen intermediate(s) has been intercepted, resulting in hydroxylation of an arene substituent on the supporting N-donor ligand. Theoretical calculations have provided intriguing mechanistic notions for the process, notably implicating hydroxylation pathways that involve novel [CuI-OOC(O)R] and [CuII-O-· ? CuIII=O2-]+ species. PMID:17958429

Hong, Sungjun; Huber, Stefan; Gagliardi, Laura; Cramer, Christopher C.; Tolman, William B.

2008-01-01

193

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. PMID:18156321

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

2008-01-01

194

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

195

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

196

Copper complexation in the Northeast Pacific  

Microsoft Academic Search

Copper titrations were conducted at sea with differential pulse anodic stripping voltammetry to examine the degree to which copper was associated with organic ligands. Greater than 99.7% of the total dissolved copper in surface waters of the central Northeast Pacific shallower than 200 m was estimated to be associated with strong organic complexes. Below 200 m, increasing proportions of inorganic

KENNETH H. COALE; KENNETH W. BRULAND

1988-01-01

197

Copper-aluminum interaction in fire environments  

Microsoft Academic Search

The surface pitting of copper conductors recovered from fire debris has been reproduced by laboratory tests. The results of\\u000a these tests demonstrate that molten aluminum that comes in contact with copper conductors drastically reduces the melting\\u000a point of copper by alloying.

Bernard Béland; C. Roy; M. Tremblay

1983-01-01

198

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

199

Copper deposition by Dynamic Chemical Plating  

Microsoft Academic Search

The present paper describes a new direct chemical plating method of copper, called Dynamic Chemical Plating. This low cost technology is based on spraying separate aqueous solutions containing copper metallic ions and Borohydride reducing agent. It is able to plate chemical copper at 30 µm\\/h at room temperature and may be used as an industrial process for metallizing polymers and

G. Stremsdoerfer; F. Ghanem; Y. Saikali; A. Fares-Karam

2003-01-01

200

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

201

HEALTH MATTERS Copper T IUD  

E-print Network

years. Less than 1 out of 100 women who use it will get pregnant each year. It starts preventing prevents pregnancy by blocking sperm from reaching an egg. It can also be inserted as emergency provider to have the Copper T IUD inserted and removed. · Most women have more bleeding and cramping

Yener, Aylin

202

Interaction between copper and gallium  

NASA Astrophysics Data System (ADS)

The interaction between solid copper and liquid gallium is considered, which is the main process during the setting of diffusion-solidifying solders. The dependences of the process rate and the size characteristics on the phase composition of the initial mixture are found. The intermetallic compound CuGa2 is shown to be the product of the interaction in all cases.

Ancharov, A. I.; Grigoryeva, T. F.; Barinova, A. P.; Boldyrev, V. V.

2008-12-01

203

Electron scattering at copper surfaces  

Microsoft Academic Search

As interconnects are scaled to smaller dimensions, the resistivity of the copper lines increases above the bulk resistivity due to a phenomena known as the size effect. Three components are known to contribute to the size effect: surface roughness, grain boundary scattering, and surface scattering. Of these, surface roughness and grain boundary scattering have been researched previously, and methods to

Jaya Murli Purswani

2008-01-01

204

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...

205

[An uncommon etiology of anemia: copper deficiency].  

PubMed

A 58-year-old patient, without any notable medical history, except for alcoholism and treated hypertension, developed anemia and leukopenia with macrocytosis. Folate deficiency was diagnosed and subsequently treated. Despite folate supplementation, the hematological parameters did not normalize. Further diagnosis investigations were led to search for uncommon etiologies of anemia and leukoneutropenia. We diagnosed severe copper deficiency on the basis of decreased plasma levels of copper and ceruloplasmin. Copper supplementation improved blood counts within three months. This case illustrates hematological disorders due to copper deficiency, initially masked by an associated folate deficiency. The copper deficiency etiology was not identified in this case. PMID:23906580

Kouamou, Edwige; Stépanian, Alain; Khadra, Fadi; de Prost, Dominique; Teillet, France

2013-01-01

206

Intracellular copper transport in cultured hepatoma cells.  

PubMed

The distribution of copper in lysates prepared anaerobically from copper-resistant hepatoma cells radiolabeled with 67Cu was examined in pulse-chase experiments. Initially, the majority of the radioactivity (greater than 85%) coeluted with copper-metallothionein. As the chase time increased there was a gradual loss of 67Cu from metallothionein, with a concomitant increase in the level of 67Cu-labeled glutathione. There was also an increase in 67Cu incorporation into superoxide dismutase. These results suggest that the chelation of copper by metallothionein from a copper-glutathione complex (Freedman, J. H., Ciriolo, M. R., and Peisach, J. (1989) J. Biol. Chem. 264, 5598-5605) is a reversible process. Further, they demonstrate that the copper bound to metallothionein is not permanently sequestered, but can be incorporated into other copper proteins. PMID:2553012

Freedman, J H; Peisach, J

1989-10-16

207

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

208

Accumulation and hyperaccumulation of copper in plants  

NASA Astrophysics Data System (ADS)

Copper is natural component of our environment. Flow of copper(II) ions in the environment depends on solubility of compounds containing this metal. Mobile ion coming from soil and rocks due to volcanic activity, rains and others are then distributed to water. Bio-availability of copper is substantially lower than its concentration in the aquatic environment. Copper present in the water reacts with other compounds and creates a complex, not available for organisms. The availability of copper varies depending on the environment, but moving around within the range from 5 to 25 % of total copper. Thus copper is stored in the sediments and the rest is transported to the seas and oceans. It is common knowledge that copper is essential element for most living organisms. For this reason this element is actively accumulated in the tissues. The total quantity of copper in soil ranges from 2 to 250 mg / kg, the average concentration is 30 mg / kg. Certain activities related to agriculture (the use of fungicides), possibly with the metallurgical industry and mining, tend to increase the total quantity of copper in the soil. This amount of copper in the soil is a problem particularly for agricultural production of food. The lack of copper causes a decrease in revenue and reduction in quality of production. In Europe, shows the low level of copper in total 18 million hectares of farmland. To remedy this adverse situation is the increasing use of copper fertilizers in agricultural soils. It is known that copper compounds are used in plant protection against various illnesses and pests. Mining of minerals is for the development of human society a key economic activity. An important site where the copper is mined in the Slovakia is nearby Smolníka. Due to long time mining in his area (more than 700 years) there are places with extremely high concentrations of various metals including copper. Besides copper, there are also detected iron, zinc and arsenic. Various plant species have adapted on such stress. The aim of this study is to investigate the behaviour of copper in plants and to assess its potential effect on the surrounding environment. To detect copper in biological samples electrochemical methods were employed particularly differential pulse voltammetry (DPV). Copper gave signals at 0.02 V measured by DPV. The obtained calibration dependence was linear (R2 = 0.995). Further, this method was utilized for determination of copper in real soil samples obtained from previously mentioned heavy-metal-polluted mining area. The content varied within range from tens to hundreds of mg of copper per kg of the soil. Moreover, we focused on investigation of copper influence on seedlings of Norway spruce. The seedlings were treated with copper (0, 0.1, 10 and 100 mM) for four weeks. We observed anatomical-morphological changes and other biochemical parameters in plants. We determined that seedlings synthesized more than 48 % protective thiols (glutathione and phytochelatins) compared to control ones. We investigated copper distribution in plant tissues by diphenylcarbazide staining. We found out that copper is highly accumulated in parenchymal stalk cells. In needles, change in auto-fluorescence of parenchymal cells of mesoderm similarly to endodermis cells. Besides, we analyzed samples of plants from the polluted area (spruce, pin, birch). The data obtained well correlated with previously mentioned. Acknowledgement The work on this experiment was supported by grant: INCHEMBIOL MSM0021622412.

Adam, V.; Trnkova, L.; Huska, D.; Babula, P.; Kizek, R.

2009-04-01

209

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. PMID:23190769

2012-01-01

210

Copper sensitivity of Oregon coastal phytoplankton  

SciTech Connect

The copper sensitivity of natural populations of Oregon coastal phytoplankton was studied using both additions of ionic copper and Cu-TRIS free ion activity buffers in coastal seawater. Phytoplankton growth rate, taxonomic composition and copper content were examined in treatment additions. The growth rate results suggested that the deficiency of another trace metal increased the apparent toxicity of copper to phytoplankton, especially in TRIS-free ion activity buffered seawater. Laboratory experiments with isolated coastal phytoplankton species indicated that manganese deficiency exacerbated copper toxicity, and that manganese deficiency was induced in TRIS buffered seawater by a TRIS-catalyzed oxidation of Mn. When manganese additions to natural populations were employed inconjunction with ionic copper additions and TRIS-free ion regulated seawater, they showed that ambient manganese concentrations were low enough to shift the onset of copper toxicity to lower copper concentrations. The results suggest that while acute toxicity to phytoplankton by ambient concentrations of copper is unlikely, the interactions of copper and other metals, especially manganese, may influence natural coastal phytoplankton populations in more subtle ways, such as taxonomic composition.

Riedel, G.F.

1983-01-01

211

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

212

Synthesis, characterization and electrochemical characterization of lead selenide sub-micron particles capped with a benzoate ligand and prepared at different temperatures  

NASA Astrophysics Data System (ADS)

Semiconductor materials offer several potential benefits as active elements in the development of harvesting-energy conversion technologies. In particular, lead selenide (PbSe) semiconductors have been used and proposed to design solar energy harvesting devices, IR sensors, FET devices, etc. Lead salts have drawn particular attention from the applied and fundamental research communities due to their exceptionally strong quantum confinement effects. Several syntheses of PbSe have been proposed using long chain surfactants to allow the formation of particles and nanoparticles. Here we present a synthesis using benzoic acid as the capping ligand in ambient atmosphere. Although the particles are not in nanometric size, we compare the crystal structure (using x-ray powder diffraction data), the near infrared and mid-infrared absorption properties of PbSe using oleic acid as the capping ligand with PbSe using benzoic acid as the capping ligand. The new synthetized particles were shown to have similar crystal structure and absorb light in the near infrared region at 1410 nm. We also performed cyclic voltammetry of these particles drop-casted in the surface of a glassy carbon electrode. The particles showed electrochemical behavior with an oxidation peak near (−402 ± 5 mV) versus Ag/AgCl reference electrode. The particles seem to form a polymeric film at the surface of a glassy carbon electrode.

Rodríguez-Rodríguez, Weyshla A.; Colón, Jadiel; Guzmán, Roger; Rivera, Harry; Santiago-Berríos, Mitk’El B.

2014-09-01

213

Evaluation of copper resistant bacteria from vineyard soils and mining waste for copper biosorption  

PubMed Central

Vineyard soils are frequently polluted with high concentrations of copper due application of copper sulfate in order to control fungal diseases. Bioremediation is an efficient process for the treatment of contaminated sites. Efficient copper sorption bacteria can be used for bioremoval of copper from contaminated sites. In this study, a total of 106 copper resistant bacteria were examined for resistance to copper toxicity and biosorption of copper. Eighty isolates (45 from vineyard Mollisol, 35 from Inceptisol) were obtained from EMBRAPA (Empresa Brasileira de Pesquisa Agropecuária) experimental station, Bento Gonçalves, RS, Brazil (29°09?53.92?S and 51°31?39.40?W) and 26 were obtained from copper mining waste from Caçapava do Sul, RS, Brazil (30°29?43.48?S and 53?32?37.87W). Based on resistance to copper toxicity and biosorption, 15 isolates were identified by 16S rRNA gene sequencing. Maximal copper resistance and biosorption at high copper concentration were observed with isolate N2 which removed 80 mg L?1 in 24 h. Contrarily isolate N11 (Bacillus pumilus) displayed the highest specific copper biosorption (121.82 mg/L/OD unit in 24 h). GenBank MEGABLAST analysis revealed that isolate N2 is 99% similar to Staphylococcus pasteuri. Results indicate that several of our isolates have potential use for bioremediation treatment of vineyards soils and mining waste contaminated with high copper concentration. PMID:24031606

Andreazza, R.; Pieniz, S.; Okeke, B.C.; Camargo, F.A.O

2011-01-01

214

Growth and stability of copper silicide thin films  

Microsoft Academic Search

Copper silicide has been investigated as a candidate material in copper-based multilevel interconnects (MLI)for application in Ultra Large Scale Integration (ULSI). The selective formation of a passivating copper silicide surface layer on a copper thin film is achieved by exposure of the copper film to a dilute silane mixture at elevated temperature. The morphology and kinetics of the surface silicide

Stephen William Hymes

1999-01-01

215

Electron scattering at copper surfaces  

NASA Astrophysics Data System (ADS)

As interconnects are scaled to smaller dimensions, the resistivity of the copper lines increases above the bulk resistivity due to a phenomena known as the size effect. Three components are known to contribute to the size effect: surface roughness, grain boundary scattering, and surface scattering. Of these, surface roughness and grain boundary scattering have been researched previously, and methods to minimize the resistivity increase due to these mechanisms have been proposed. The focus of this thesis research was to address the issue of surface scattering, which is the least understood component of the size effect. In particular, little is known about the materials and surface structure which lead to completely specular scattering (i.e. no increase in resistivity for thin layers). This research has built on the reported observation of partial specular scattering in both gold and silver films. The most promising layers have been shown to be single crystals. These single crystal films have the added advantage of simplifying the resistivity characterization, as there is no grain boundary component to the resistivity. Thus, particular focus was spent on determining the growth conditions required to produce high quality single crystal copper layers. Epitaxial copper layers were grown on single crystal magnesium oxide substrates with (001)Cu||(001)MgO with [001]Cu ||[001]MgO for samples grown at a substrate temperature T s of 100°C or less. The lattice mismatch between copper and MgO is 14.29%, which is resolved by 7x7 copper unit cells occupying 6x6 MgO cells. The highest crystalline quality was found for those layers grown at Ts = 100°C, while the layers grown at Ts = 40°C demonstrated the smoothest surface and lowest buried interface roughness. Surface morphology was studied through the use of in-situ scanning tunneling microscopy (STM). From these characterizations, the epitaxial copper surfaces have a self-affine surface structure, with a scaling exponent alpha of 0.82+/-0.03, independent of annealing. The mound width increased from 31+/-8 to 39+/-6 nm for increasing layer thickness, d, of 24 and 120 nm, respectively. The heights of the as-deposited mounds were nearly constant, independent of film thickness. In-situ annealing at Ta = 200 and 300°C results in thermodynamically driven mass transport that minimized the surface step density. This resulted in mounds with a larger mound radius and smaller root mean square roughness alpha. The effect was most pronounced on the thinnest layer, d = 24 nm, with the mound radius increasing from 31+/-8 to 70+/-20 nm, and sigma decreasing from 1.3+/-0.1 to 0.74+/-0.08 nm, for the as-deposited and 300°C annealed layers, respectively. Thus annealing resulted in a reduction in the mound aspect ratio when compared to the as-deposited layers. In the best case, terrace widths were increased from 1.5 to 6.3 nm, for the 24-nm-thick as-deposited and 300°C annealed layer, respectively. These terrace widths correspond to terraces which consist of 6 to 25 atoms per step. Further annealing at higher temperatures resulted in rough, partially discontinuous layers, attributed to oxidation of the copper-substrate interface as well as thermodynamically driven copper islanding in order to reduce the interfacial area between the copper and magnesium oxide. Electron transport experiments have shown that resistivity is highly dependent on the crystalline quality of the copper layers. Single crystal copper layers have resistivities that are a minimum of four times smaller than the polycrystalline layers, which is due to the absence of grain boundaries, which act as additional scattering centers. As-deposited copper layers resulted in completely diffuse scattering, which was attributed to the short length scales of atomically smooth terraces. Annealing resulted in layers which were smoother, but all layers exhibited completely diffuse surface scattering with a specularity parameter of p = 0. Low temperature and in-situ electron transport measurements were used in order to determine whether oxidation

Purswani, Jaya Murli

216

Regenerative synthesis of copper nanoparticles by photoirradiation  

NASA Astrophysics Data System (ADS)

Copper nanoparticles have attracted much attention because of their low cost, and because their use can contribute toward the sustainability of metal resources. In this study, copper nanoparticles were synthesized by the photoirradiation of copper acetate solution at room temperature. The diameter and chemical composition of the obtained copper nanoparticles were analyzed using field-emission scanning electron microscope (FE-SEM) spectrophotometer and an X-ray photoelectron spectrometer. Well-dispersed copper nanoparticles with ~5 nm in diameter were observed in the solution. On the other hand, when the nanoparticle solution was exposed to fresh air, nanoparticles were not observed in the solution. Furthermore, the copper nanoparticles were recovered from a solution of decomposed nanoparticles by re-photoirradiation.

Nishida, N.; Miyashita, A.; Hashimoto, N.; Murayama, H.; Tanaka, H.

2011-07-01

217

Hydrated copper oxalate, moolooite, in lichens  

E-print Network

Vivid blue inclusions in white whewellite or weddellite, occurring within the medulla of four lichen species growing on copper-bearing rocks, have been identified as the hydrated copper oxalate, moolooite, CUC204. nH20 (n ~ 0.4-0.7), by infrared spectroscopy and X-ray powder diffraction. The mineral is believed to have been formed by reaction between oxalic acid secreted by the lichen and ground or surface water containing copper.

J. E. Chisholm; G. C. Jones; O. W. Purvis

218

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

219

The direct electrorefining of copper matte  

NASA Astrophysics Data System (ADS)

Direct electrorefining of copper matte would be a desirable alternative to copper converting and its associated troublesome sulfur dioxide emissions. After more than 100 years of study, however, no commercial process has been developed, even though an analogous process for the direct electrorefining of nickel matte anodes has been operating successfully for several decades. The unique difficulties associated with copper matte electrorefining are related to the properties of the matte's decomposition products.

McKay, Douglas J.

1993-03-01

220

The production of copper parts using DMLR  

Microsoft Academic Search

The relationship between the major process variables (laser power, laser scan speed, scan length, beam overlap and Q-switch pulse frequency) of direct metal laser re-melting and their effect on the structure of single- and multi-layer copper coupons has been investigated. The work successfully produced selectively fused copper powder layers and simple three-dimensional copper structures with suitable laser parameters being identified

S. R. Pogson; P. Fox; C. J. Sutcliffe; W. O’Neill

2003-01-01

221

Copper-binding proteins in human erythrocytes: Searching for potential biomarkers of copper over-exposure  

Microsoft Academic Search

The recognition that copper is essential but also potentially toxic to humans has prompted the search for biomarkers of copper excess. The experimental approach followed here involves the isolation and subsequent characterization of copper-binding molecules (CuBP) from human erythrocytes. Incubation (0–60 min) of freshly obtained erythrocytes in the presence of increasing concentrations of copper (10–50 µM; as 64Cu-histidine) led to time- and

Hernán Speisky; Paola Navarro; M. George Cherian; Inés Jiménez

2003-01-01

222

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

223

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

224

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

225

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

226

Removal efficiency and binding mechanisms of copper and copper-EDTA complexes using polyethyleneimine.  

PubMed

Copper is used extensively in semiconductor circuits as the multilayer metal. In addition to copper, waste streams often contain chelating agents like EDTA, which is widely used in the process to enhance solubility of copper, and it tends to form copper-chelated complexes. PEI--agarose adsorbents in a packed-bed column are capable of removing these anionic complexes, but the competitive binding between this chelating agent and PEI for copper is not well understood and needs to be explored. The current work focuses on investigating copper sorption by PEI-agarose adsorbent in the presence of EDTA. The pH of the column is fixed at 5.5 using 0.1 M acetate buffer. The ratio of chelator to copper ions is varied. Copper binding capacity and copper breakthrough curves are compared and contrasted to results without additional chelator present. An excess of EDTA leads to an increase in the fraction of free dissociated (anionic) ligand that competes for electrostatic attraction on protonated amine groups and therefore leads to a decrease in sorption capacity in the column. However, this waste treatment technique is still feasible for the semiconductor industry as large volumes of copper-contaminated solutions from actual waste can be concentrated 12-fold. When equimolar (copper to EDTA) or higher concentrations of EDTA are present, acetate can be utilized to recover the metal; for low ratios of copper to EDTA, metal recovery is achieved using hydrochloric acid. PMID:18409647

Maketon, Worawan; Zenner, Chase Z; Ogden, Kimberly L

2008-03-15

227

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

228

Neutron-activation analysis applied to copper ores and artifacts  

NASA Technical Reports Server (NTRS)

Neutron activation analysis is used for quantitative identification of trace metals in copper. Establishing a unique fingerprint of impurities in Michigan copper would enable identification of artifacts made from this copper.

Linder, N. F.

1970-01-01

229

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. PMID:24740976

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

2014-01-01

230

7 CFR 1755.403 - Copper cable telecommunications plant measurements.  

Code of Federal Regulations, 2013 CFR

...with temperature change. For copper conductor cables, the dc resistance changes...use the following value for copper conductors: For each ±5 °F (±2...use the following value for copper conductors: For each ±10 °F...

2013-01-01

231

7 CFR 1755.403 - Copper cable telecommunications plant measurements.  

Code of Federal Regulations, 2011 CFR

...with temperature change. For copper conductor cables, the dc resistance changes...use the following value for copper conductors: For each ±5 °F ( ±2...use the following value for copper conductors: For each ±10 °F...

2011-01-01

232

7 CFR 1755.403 - Copper cable telecommunications plant measurements.  

Code of Federal Regulations, 2012 CFR

...with temperature change. For copper conductor cables, the dc resistance changes...use the following value for copper conductors: For each ±5 °F ( ±2...use the following value for copper conductors: For each ±10 °F...

2012-01-01

233

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.

234

Ternary lanthanum sulfide selenides {alpha}-LaS{sub 2-x}Se{sub x} (0  

SciTech Connect

Mixed lanthanum sulfide selenides LaS{sub 2-x}Se{sub x} (0selenides. Highlights: Black-Right-Pointing-Pointer Vegard series of mixed lanthanum sulfide selenides LaS{sub 2-x}Se{sub x} (0

Bartsch, Christian [Department of Chemistry and Food Chemistry, Technische Universitaet Dresden, D-01062 Dresden (Germany); Doert, Thomas, E-mail: thomas.doert@chemie.tu-dresden.de [Department of Chemistry and Food Chemistry, Technische Universitaet Dresden, D-01062 Dresden (Germany)

2012-01-15

235

{[M(NH3)6][Ag4M4Sn3Se13]}? (M=Zn, Mn): Three-dimensional chalcogenide frameworks constructed from quaternary metal selenide clusters with two different transition metals  

NASA Astrophysics Data System (ADS)

Herein we report solvothermal syntheses of two new three-dimensional chalcogenide frameworks {[M(NH3)6][Ag4M4Sn3Se13]}n (M=Zn (1), Mn (2)), which consist of quaternary metal selenide clusters with two different transition metals. The compounds represent the first Ag-Zn/Mn-Sn-Se based quaternary anionic frameworks. The optical studies show that the band gaps for 1 and 2 are 2.09 eV and 1.71 eV, respectively. Moreover, the photoelectrochemical study indicates that compound 1 displays n-type semiconducting behaviour and is photoactive under visible light illumination (?>400 nm).

Xiong, Wei-Wei; Miao, Jianwei; Li, Pei-Zhou; Zhao, Yanli; Liu, Bin; Zhang, Qichun

2014-10-01

236

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

237

Inborn errors of copper metabolism  

PubMed Central

SUMMARY Wilson disease, Menkes disease, occipital horn syndrome, and X-linked distal hereditary motor neuropathy are genetic disorders of copper metabolism that span a broad spectrum of neurological dysfunction (Table 180.1). The occurrence of these disorders indicates the fundamental importance of ATP7A and ATP7B. Further research to clarify the mechanisms suggested by these clinical and biochemical phenotypes may yield insight about the roles of ATP7A and ATP7B in neuronal cells, and lead to improved treatments. PMID:23622398

KALER, STEPHEN G.

2014-01-01

238

Structural, magnetic, and electronic properties of iron selenide Fe6-7Se8 nanoparticles obtained by thermal decomposition in high-temperature organic solvents  

NASA Astrophysics Data System (ADS)

Iron selenide nanoparticles with the NiAs-like crystal structure were synthesized by thermal decomposition of iron chloride and selenium powder in a high-temperature organic solvent. Depending on the time of the compound processing at 340 °C, the nanocrystals with monoclinic (M)-Fe3Se4 or hexagonal (H)-Fe7Se8 structures as well as a mixture of these two phases can be obtained. The magnetic behavior of the monoclinic and hexagonal phases is very different. The applied-field and temperature dependences of magnetization reveal a complicated transformation between ferrimagnetic (FRM) and antiferromagnetic (AFM) structures, which can be related to the spin rotation process connected with the redistribution of cation vacancies. From XRD and Mössbauer data, the 3c type superstructure of vacancy ordering was found in the hexagonal Fe7Se8. Redistribution of vacancies in Fe7Se8 from random to ordered leads to the transformation of the magnetic structure from FRM to AFM. The Mössbauer data indicate that vacancies in the monoclinic Fe3Se4 prefer to appear near the Fe3+ ions and stimulate the magnetic transition with the rotation of the Fe3+ magnetic moments. Unusually high coercive force Hc was found in both (H) and (M) nanocrystals with the highest ("giant") value of about 25 kOe in monoclinic Fe3Se4. This is explained by the strong surface magnetic anisotropy which is essentially larger than the core anisotropy. Such a large coercivity is rare for materials without rare earth or noble metal elements, and the Fe3Se4-based compounds can be the low-cost, nontoxic alternative materials for advanced magnets. In addition, an unusual effect of "switching" of magnetization in a field of 10 kOe was found in the Fe3Se4 nanoparticles below 280 K, which can be important for applications.

Lyubutin, I. S.; Lin, Chun-Rong; Funtov, K. O.; Dmitrieva, T. V.; Starchikov, S. S.; Siao, Yu-Jhan; Chen, Mei-Li

2014-07-01

239

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

240

Potentially novel copper resistance genes in copper-enriched activated sludge revealed by metagenomic analysis.  

PubMed

In this study, we utilized the Illumina high-throughput metagenomic approach to investigate diversity and abundance of both microbial community and copper resistance genes (CuRGs) in activated sludge (AS) which was enriched under copper selective stress up to 800 mg/L. The raw datasets (~3.5 Gb for each sample, i.e., the copper-enriched AS and the control AS) were merged and normalized for the BLAST analyses against the SILVA SSU rRNA gene database and self-constructed copper resistance protein database (CuRD). Also, the raw metagenomic sequences were assembled into contigs and analyzed based on Open Reading Frames (ORFs) to identify potentially novel copper resistance genes. Among the different resistance systems for copper detoxification under the high copper stress condition, the Cus system was the most enriched system. The results also indicated that genes encoding multi-copper oxidase played a more important role than those encoding efflux proteins. More significantly, several potentially novel copper resistance ORFs were identified by Pfam search and phylogenic analysis. This study demonstrated a new understanding of microbial-mediated copper resistance under high copper stress using high-throughput shotgun sequencing technique. PMID:25081552

Li, Li-Guan; Cai, Lin; Zhang, Xu-Xiang; Zhang, Tong

2014-12-01

241

Mechanical Separation of Metallic Copper from Polymer-Insulated Copper Wire  

SciTech Connect

It is very important to recycling of polymer-insulated copper wire to remove copper from the wire without any contamination. A rolling machine and a blender were used to separate and recover the copper wires from a polymer coated cable. In the experiment using a rolling machine, the recovery of copper was improved by an increase in the number of rolling times and by lowering the cable temperature. All of the copper was recovered from a cable of 115 K in temperature. In the other experiment using a blender, the weight of the recovery of copper was increased by shortening the cable length and by increasing the rotary speed of the blender and the treating time. All the copper in a cut cable of 3mm long was recovered from a cable.

Yokoyama, Seiji [Department of Mechanical Engineering, Toyohashi University of Technology, (1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi, 441-8105, JAPAN) (Japan); Takeuchi, Sakae [Graduate School of Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi, 441-8105 (Japan); Hisyamudin Bin Muhd Nor, Nik [Department of Mechanical and Manufacturing Engineering, University Tun Hussein Onn Malaysia (Now, Graduate School of Toyohashi University of Technology) (Malaysia)

2011-01-17

242

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...

243

Fetal polyol metabolism in copper deficiency  

SciTech Connect

Since pregnant rats consuming fructose, copper deficient diets fail to give birth, the relationship between maternal copper deficiency, polyol metabolism and fetal mortality was investigated. Forty Sprague-Dawley rats were fed from conception one of the following diets: fructose, copper deficient; fructose, copper adequate; starch, copper deficient or starch, copper adequate. The deficient diets contained 0.6 ug Cu and the adequate 6.0 ug Cu/g diet. Pregnancy was terminated at day 19 of gestation. Glucose, sorbitol and fructose were measured in maternal blood, placenta and fetal liver. Fructose consumption during pregnancy resulted in higher levels of fructose and sorbitol in maternal blood when compared to starch. In the fructose dietary groups, the placenta and fetal liver contained extremely high levels of glucose, fructose and sorbitol compared to the corresponding metabolites from the starch dietary groups. Copper deficiency further elevated fructose and sorbitol concentrations in the placenta and fetal liver respectively. Since high tissue levels of glucose, fructose and sorbitol have been shown to have deleterious effects on cellular metabolism, these data suggest that when fructose was fed during pregnancy the combination of an aberration of carbohydrate metabolism with copper deficiency could be responsible for the pathology and mortality of the developing fetus.

Fields, M.; Lewis, C.G.; Beal, T. (Georgetown Univ. Medical Center, Washington, DC (USA))

1989-02-09

244

Transport and Fate of Copper in Soils  

Microsoft Academic Search

The presence of toxic heavy metals in industrial effluents is one of the serious threats to the environment. Heavy metals such as Cadmium, Chromium, Lead, Nickel, Zinc, Mercury, Copper, Arsenic are found in the effluents of industries such as foundries, electroplating, petrochemical, battery manufacturing, tanneries, fertilizer, dying, textiles, metallurgical and metal finishing. Tremendous increase of industrial copper usage and its

S K Sharma; N S Sehkon; S Deswal; Siby John

2009-01-01

245

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 ...

246

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

247

Copper exposure effects on yeast mitochondrial proteome.  

PubMed

Mitochondria play an important role on the entire cellular copper homeostatic mechanisms. Alteration of cellular copper levels may thus influence mitochondrial proteome and its investigation represents an important contribution to the general understanding of copper-related cellular effects. In these study we have performed an organelle targeted proteomic investigation focusing our attention on the effect of non-lethal 1mM copper concentration on Saccharomyces cerevisiae mitochondrial proteome. Functional copper effects on yeast mitochondrial proteome were evaluated by using both 2D electrophoresis (2-DE) and liquid chromatography coupled with tandem mass spectrometry. Proteomic data have been then analyzed by different unsupervised meta-analysis approaches that highlight the impairment of mitochondrial functions and the activation of oxidative stress response. Interestingly, our data have shown that stress response generated by 1mM copper treatment determines the activation of S. cerevisiae survival pathway. To investigate these findings we have treated yeast cells responsiveness to copper with hydrogen peroxide and observed a protective role of this metal. These results are suggestive of a copper role in the protection from oxidative stress possibly due to the activation of mechanisms involved in cellular survival and growth. PMID:21549866

Banci, Lucia; Bertini, Ivano; Ciofi-Baffoni, Simone; D'Alessandro, Annamaria; Jaiswal, Deepa; Marzano, Valeria; Neri, Sara; Ronci, Maurizio; Urbani, Andrea

2011-10-19

248

Copper Metallization for High Performance Silicon Technology  

NASA Astrophysics Data System (ADS)

The increasingly rapid transition of the electronics industry to high-density, high-performance multifunctional microprocessor Si technology has precipitated migration to new materials alternatives that can satisfy stringent requirements. One of the recent innovations has been the substitution of copper for the standard aluminum-copper metal wiring in order to decrease resistance and tailor RC delay losses in the various hierarchies of the wiring network. This has been accomplished and the product shipped only since the fall of 1998, after more than a decade of intensive development. Critical fabrication innovations include the development of an electroplating process for the copper network, dual-damascence chem-mech polishing (CMP), and effective liner material for copper diffusion barrier and adhesion promotion. The present copper technology provides improved current-carrying capability by higher resistance to electromigration, no device contamination by copper migration, and the performance enhancement analytically predicted. This success of the shift to copper will accelerate the industry movement to finer features and more complex interconnect structures with sufficient device density and connectivity to integrate full systems on chips. The next innovation will be the introduction of low-dielectric constant material that, in combination with copper, will create added excitement as the industry learns how to utilize this new capability.

Rosenberg, R.; Edelstein, D. C.; Hu, C.-K.; Rodbell, K. P.

2000-08-01

249

An externally heated copper vapour laser  

Microsoft Academic Search

A pulsed Copper Vapor Laser (CVL), with a nominal 6 kHz repetition rate, was designed, built, and commissioned at Chalk River Laboratories. The laser was required for Resonant Ionization Mass Spectroscopy (RIMS) experiments and for projects associated with Atomic Vapour Laser Isotope Separation (AVLIS) studies. For the laser to operate, copper coupons positioned along the length of a ceramic tube

P. A. Rochefort; F. C. Sopchyshyn; E. B. Selkirk; L. W. Green

1993-01-01

250

COPPER PITTING AND PINHOLE LEAK RESEARCH STUDY  

EPA Science Inventory

Localized copper corrosion or pitting is a significant problem at many water utilities across the United States. Copper pinhole leak problems resulting from extensive pitting are widely under reported. Given the sensitive nature of the problem, extent of damage possible, costs o...

251

Sorption of copper by olive mill residues  

Microsoft Academic Search

A study on olive mill residues (OMR) as copper adsorbing material is reported in this work. A rough characterization of this waste material has been performed, by microanalysis and SEM pictures. Sorption tests with suspended OMR evidenced copper removal from solution, of about 60% in the investigated experimental conditions. The COD release in solution was also monitored during biosorption. Considering

F Vegliò; F Beolchini; M Prisciandaro

2003-01-01

252

Lead and Copper Control 101-slides  

EPA Science Inventory

This presentation is an overview of the most important water treatment strategies for the control of lead and copper release from drinking water corrosion. In addition to the sections specifically on lead and copper treatment, sections are included that cover sampling to find le...

253

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

254

Photoluminescence Properties of the Diluted Magnetic Semiconductors ZINC(1-X)MANGANESE(X)SELENIDE and CADMIUM(1 -  

NASA Astrophysics Data System (ADS)

Time-resolved and cw photoluminescence measurements were carried out on the diluted magnetic semiconductors Zn_{rm 1-x}Mn _{rm x}Se and Cd _{rm 1-x}Mn_ {rm x}Se; high manganese concentration was emphasized. Zn_{rm 1-x}Mn _{rm x}Se samples with 0 <= x <= 0.49 were investigated; four emission bands at ~2.15eV, ~2.03eV, ~1.95eV, and ~1.35 eV were observed. The bands of ~2.15 eV, ~2.03eV, and ~1.95eV were ascribed to Mn^ {2+} ^4T _1 to ^6 A_1 intraion transition, self-activated emission, and copper related emission, respectively. The temperature dependences and decay characteristics of these three bands were investigated for 18 < T < 136K. The ~2.15eV band decays monotonically, while the ~2.03 eV and ~1.95eV bands show a slow build up effect, the latter effect indicating the presence of energy transfer in the excitation of these two bands. Thermal quenching of the ~2.03 eV and ~1.95eV bands occur below 60K. An energy level scheme is suggested which takes into account mechanisms proposed for similar emissions in ZnSe. Time-resolved measurements on the ~2.13 eV and ~1.35eV photoluminescence bands in Cd_{rm 1-x}Mn _{rm x}Se were carried out for 18 < T < 300K and selected excitation energies 2.035eV < hnu_{rm ex} < 2.36eV. The ~2.13eV band is observable in an x = 0.48 sample; its decay is monotonic. For samples with x = 0.28 and x = 0.48, the ~1.35eV band exhibits complicated build up processes. A phenomenological model is presented which gives good agreement with data for the ~2.13 eV emission. The model ascribes the ~2.13 eV emission to the Mn^{2+} ^4T_1 to ^6A _1 transition, and assumes a two-level system and energy transfer between these levels. The excitation results on the ~1.35eV emisison suggest that the energy transfer from Mn ^4 T_1 excited states is an important source of excitation of this band for h nu_{rm ex} > 2.3eV, but two photon excitation of the ~2.13eV band or a similar mechanism is needed to explain the results of hnu_{ rm ex} < 2.3eV.

Wang, Bonnie I.-Keh

1987-09-01

255

A Bright Future for copper electrowinning  

NASA Astrophysics Data System (ADS)

Over the past 40 years, the copper mining industry has undergone a dramatic shift toward hydrometallurgical extraction of copper at the mine site. This has increased the importance of recovering high-purity copper by electrowinning. High-purity cathode production was achieved by implementing numerous technologies including superior lead-alloy anodes, improved cathode handling and/or stainless steel blanks, better electrolyte control, and advanced tankhouse automation. In the future, it is projected that tankhouses will produce high-quality copper at lower costs using technologies that could include dimensionally stable anodes, alternative anode reactions, innovative cell designs, novel electrolyte circulation systems, and more. This paper reviews existing commercial copper electrowinning technologies and discusses advances that need to be made to implement future technologies.

Moats, Michael; Free, Michael

2007-10-01

256

Copper accumulation in channel catfish (Ictalurus punctatus) exposed to water borne copper sulfate  

SciTech Connect

Liver and axial muscle of channel catfish (Ictalurus punctatus) was analyzed for residual copper after exposure to water borne copper sulfate. Copper sulfate was continuously introduced into well water in three fiber glass tanks to achieve 1.7 mg/L, 2.7 mg/L and 3.6 mg/L copper sulfate concentrations in exposure waters. Milli-Q quality water was metered into a fourth tank at the same rate for unexposed fish. Actual levels of copper in exposure waters were determined by daily sampling and analysis by graphite furnace atomic absorption spectrophotometry (GFAA). Tissue samples were taken from six fish from each of the exposed and unexposed tanks at two-week intervals, Samples were collected until tissue analysis indicated an equilibrium had been established between the uptake and elimination in both the muscle and liver tissue. Elimination was followed until a clear rate of deputation could be established. Samples were digested in nitric acid in a micro wave digestor and analyzed by GFAA. Results of tissue analysis will be presented to demonstrate bioaccumulation and the effect of copper concentration, length of copper exposure, and gender on copper uptake, establishment of tissue:environmental copper equilibrium, and rate of copper elimination following exposure.

Hobbs, M. [Oak Ridge Inst. for Science and Education, TN (United States); Griffin, B. [National Biological Service, Stuttgart, AR (United States); Schlenk, D. [Univ. of Mississippi, Oxford, MS (United States); Kadlubar, F.; Brand, C.D. [National Center for Toxicological Research, Jefferson, AR (United States)

1995-12-31

257

Molecular Responses of Mouse Macrophages to Copper and Copper Oxide Nanoparticles Inferred from Proteomic Analyses*  

PubMed Central

The molecular responses of macrophages to copper-based nanoparticles have been investigated via a combination of proteomic and biochemical approaches, using the RAW264.7 cell line as a model. Both metallic copper and copper oxide nanoparticles have been tested, with copper ion and zirconium oxide nanoparticles used as controls. Proteomic analysis highlighted changes in proteins implicated in oxidative stress responses (superoxide dismutases and peroxiredoxins), glutathione biosynthesis, the actomyosin cytoskeleton, and mitochondrial proteins (especially oxidative phosphorylation complex subunits). Validation studies employing functional analyses showed that the increases in glutathione biosynthesis and in mitochondrial complexes observed in the proteomic screen were critical to cell survival upon stress with copper-based nanoparticles; pharmacological inhibition of these two pathways enhanced cell vulnerability to copper-based nanoparticles, but not to copper ions. Furthermore, functional analyses using primary macrophages derived from bone marrow showed a decrease in reduced glutathione levels, a decrease in the mitochondrial transmembrane potential, and inhibition of phagocytosis and of lipopolysaccharide-induced nitric oxide production. However, only a fraction of these effects could be obtained with copper ions. In conclusion, this study showed that macrophage functions are significantly altered by copper-based nanoparticles. Also highlighted are the cellular pathways modulated by cells for survival and the exemplified cross-toxicities that can occur between copper-based nanoparticles and pharmacological agents. PMID:23882024

Triboulet, Sarah; Aude-Garcia, Catherine; Carriere, Marie; Diemer, Helene; Proamer, Fabienne; Habert, Aurelie; Chevallet, Mireille; Collin-Faure, Veronique; Strub, Jean-Marc; Hanau, Daniel; Van Dorsselaer, Alain; Herlin-Boime, Nathalie; Rabilloud, Thierry

2013-01-01

258

Original article Effects of selenium and copper administration on blood  

E-print Network

Original article Effects of selenium and copper administration on blood selenium and copper profile; Forty yearling shorthorn heifers were winter-fed barley silage, a diet low in copper and selenium treatments were copper (Cu), selenium (Se), or combined Cu-Se administered by subcutaneous injections. Low Cu

Boyer, Edmond

259

Ris0-R-991(EN) Fatigue Performance of Copper and  

E-print Network

Results 7 3.1 Pre- and Post-irradiation Microstructure 7 3.2 Fatigue Life Evaluation 8 3.3 Cyclic StressRis0-R-991(EN) inn DK9700117 Fatigue Performance of Copper and Copper alloys before and after ARE MISSING IN THE ORIGINAL DOCUMENT #12;Fatigue Performance of Copper and Copper alloys before and after

260

Copper emissions from antifouling paint on recreational vessels  

Microsoft Academic Search

Trace metals, especially copper, are commonly occurring contaminants in harbors and marinas. One source of copper to these environs is copper-based antifouling coatings used on vessel hulls. The objective of this study was to measure dissolved copper contributions from recreational vessel antifouling coatings for both passive leaching and hull cleaning activities. To accomplish this goal, three coating formulations, including hard

Kenneth Schiff; Dario Diehl; Aldis Valkirs

2004-01-01

261

Treatment of Copper from Cu CMP Waste Streams Using Polyethyleneimine  

Microsoft Academic Search

Commercially available Cu CMP waste treatment processes involve: 1) pretreatment chemistry using oxidizers to break down complexed copper resulting in precipitation of copper in the form of copper hydroxide; 2) microfiltration of both slurry particles and copper hydroxide; and 3) ion exchange to remove ions. Ion exchange resins used to remove ions are limited to only removing cations and also

Worawan Kay Maketon; Kimberly L. Ogden

2008-01-01

262

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

263

Copper: toxicological relevance and mechanisms.  

PubMed

Copper (Cu) is a vital mineral essential for many biological processes. The vast majority of all Cu in healthy humans is associated with enzyme prosthetic groups or bound to proteins. Cu homeostasis is tightly regulated through a complex system of Cu transporters and chaperone proteins. Excess or toxicity of Cu, which is associated with the pathogenesis of hepatic disorder, neurodegenerative changes and other disease conditions, can occur when Cu homeostasis is disrupted. The capacity to initiate oxidative damage is most commonly attributed to Cu-induced cellular toxicity. Recently, altered cellular events, including lipid metabolism, gene expression, alpha-synuclein aggregation, activation of acidic sphingomyelinase and release of ceramide, and temporal and spatial distribution of Cu in hepatocytes, as well as Cu-protein interaction in the nerve system, have been suggested to play a role in Cu toxicity. However, whether these changes are independent of, or secondary to, an altered cellular redox state of Cu remain to be elucidated. PMID:25199685

Gaetke, Lisa M; Chow-Johnson, Hannah S; Chow, Ching K

2014-11-01

264

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

265

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. 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

266

Copper trafficking in biology: an NMR approach  

PubMed Central

Copper ions are essential for living organisms because they are involved in several fundamental biological processes. Biomolecules interacting with copper ions have to be characterized as such, when bound to the metal ion, and when they interact with other biomolecules or substrates. The characterization is both structural and dynamic. In this context, NMR is a preferred tool of investigation because it allows shedding light on what happens in solution. Here, the NMR contribution to the copper trafficking is described, providing precious information on biochemical pathways, which are essential to understand the mechanisms of life at the molecular level. PMID:19949444

Banci, Lucia; Bertini, Ivano; Ciofi-Baffoni, Simone

2009-01-01

267

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

268

Copper localization, elemental content, and thallus colour in the copper hyperaccumulator lichen Lecanora sierrae from California  

USGS Publications Warehouse

An unusual dark blue-green lichen, Lecanora sierrae, was discovered over 30 years ago by Czehura near copper mines in the Lights Creek District, Plumas County, Northern California. Using atomic absorption spectroscopy, Czehura found that dark green lichen samples from Warren Canyon contained 4% Cu in ash and suggested that its colour was due to copper accumulation in the cortex. The present study addressed the hypothesis that the green colour in similar material we sampled from Warren Canyon in 2008, is caused by copper localization in the thallus. Optical microscopy and electron microprobe analysis of specimens of L. sierrae confirmed that copper localization took place in the cortex. Elemental analyses of L. sierrae and three other species from the same localities showed high enrichments of copper and selenium, suggesting that copper selenates or selenites might occur in these lichens and be responsible for the unusual colour. Copyright ?? 2011 British Lichen Society.

Purvis, O.W.; Bennett, J.P.; Spratt, J.

2011-01-01

269

Copper localization, elemental content, and thallus colour in the copper hyperaccumulator lichen Lecanora sierra from California  

USGS Publications Warehouse

An unusual dark blue-green lichen, Lecanora sierrae, was discovered over 30 years ago by Czehura near copper mines in the Lights Creek District, Plumas County, Northern California. Using atomic absorption spectroscopy, Czehura found that dark green lichen samples from Warren Canyon contained 4% Cu in ash and suggested that its colour was due to copper accumulation in the cortex. The present study addressed the hypothesis that the green colour in similar material we sampled from Warren Canyon in 2008, is caused by copper localization in the thallus. Optical microscopy and electron microprobe analysis of specimens of L. sierrae confirmed that copper localization took place in the cortex. Elemental analyses of L. sierrae and three other species from the same localities showed high enrichments of copper and selenium, suggesting that copper selenates or selenites might occur in these lichens and be responsible for the unusual colour.

Purvis, O. W.; Bennett, J. P.; Spratt, J.

2011-01-01

270

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

271

Purification of human copper, zinc superoxide dismutase by copper chelate affinity chromatography  

SciTech Connect

Copper, zinc superoxide dismutase was isolated from human red blood cell hemolysate by DEAE-Sepharose and copper chelate affinity chromatography. Enzyme preparations had specific activities ranging from 3400 to 3800 U/mg and recoveries were approximately 60% of the enzyme activity in the lysate. Copper chelate affinity chromatography resulted in a purification factor of about 60-fold. The homogeneity of the superoxide dismutase preparation was analyzed by sodium dodecyl sulfate-gel electrophoresis, analytical gel filtration chromatography, and isoelectric focusing.

Weslake, R.J.; Chesney, S.L.; Petkau, A.; Friesen, A.D.

1986-05-15

272

Formation of Copper Sulfide Artifacts During Electrolytic Dissolution of Steel  

NASA Astrophysics Data System (ADS)

Based on equilibrium considerations, copper sulfide is not expected to form in manganese-containing steel, yet previous workers reported finding copper sulfide in transmission electron microscope samples which had been prepared by electropolishing. It is proposed that copper sulfide can form during electrolytic dissolution because of the much greater stability of copper sulfide relative to manganese sulfide in contact with an electrolyte containing copper and manganese cations. This mechanism has been demonstrated with aluminum-killed steel samples.

Tan, Jia; Pistorius, P. Chris

2013-06-01

273

Effects of stimulation of copper bioleaching on microbial community in vineyard soil and copper mining waste.  

PubMed

Long-term copper application in vineyards and copper mining activities cause heavy metal pollution sites. Such sites need remediation to protect soil and water quality. Bioremediation of contaminated areas through bioleaching can help to remove copper ions from the contaminated soils. Thus, the aim of this work was to evaluate the effects of different treatments for copper bioleaching in two diverse copper-contaminated soils (a 40-year-old vineyard and a copper mining waste) and to evaluate the effect on microbial community by applying denaturing gradient gel electrophoresis (DGGE) of 16S ribosomal DNA amplicons and DNA sequence analysis. Several treatments with HCl, H(2)SO(4), and FeSO(4) were evaluated by stimulation of bioleaching of copper in the soils. Treatments and extractions using FeSO(4) and H(2)SO(4) mixture at 30°C displayed more copper leaching than extractions with deionized water at room temperature. Treatment with H(2)SO(4) supported bioleaching of as much as 120 mg kg(-1) of copper from vineyard soil after 115 days of incubation. DGGE analysis of the treatments revealed that some treatments caused greater diversity of microorganisms in the vineyard soil compared to the copper mining waste. Nucleotide Blast of PCR-amplified fragments of 16S rRNA gene bands from DGGE indicated the presence of Rhodobacter sp., Silicibacter sp., Bacillus sp., Paracoccus sp., Pediococcus sp., a Myxococcales, Clostridium sp., Thiomonas sp., a firmicute, Caulobacter vibrioides, Serratia sp., and an actinomycetales in vineyard soil. Contrarily, Sphingomonas was the predominant genus in copper mining waste in most treatments. Paracoccus sp. and Enterobacter sp. were also identified from DGGE bands of the copper mining waste. Paracoccus species is involved in the copper bioleaching by sulfur oxidation system, liberating the copper bounded in the soils and hence promoting copper bioremediation. Results indicate that stimulation of bioleaching with a combination of FeSO(4) and H(2)SO(4) promoted bioleaching in the soils and can be employed ex situ to remediate copper-impacted soils. PMID:21947860

Andreazza, Robson; Okeke, Benedict C; Pieniz, Simone; Bortolon, Leandro; Lambais, Márcio R; Camargo, Flávio A O

2012-04-01

274

Effect of stainless steel on corrosion behavior of copper in a copper-bearing intrauterine device.  

PubMed

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 of stainless steel was found to play a decisive role. In most cases, when stainless steel was in the passive state and acted as the cathode, the contact accelerated copper corrosion. In addition, the area ratio of stainless steel to copper altered copper corrosion behavior. The larger the area of stainless steel, the greater the acceleration of copper corrosion. It was noted that the stainless steel surface might be activated due to improper handling of the IUD. In this case, copper became the cathode of the couple and its corrosion was suppressed. PMID:9820933

Xue, H; Xu, N; Zhang, C

1998-06-01

275

BIOCHEMISTRY: Free Copper Ions in the Cell?  

NSDL National Science Digital Library

Access to the article is free, however registration and sign-in are required. How enzymes such as copper-zinc superoxide dismutase (SOD1), an important antioxidant enzyme in the cell, obtain the transition metal ions that they need to function is still far from understood. In Science this week, Rae et al. demonstrate that the yCCS metallochaperone in yeast inserts copper ions directly into the enzyme and is only active at very low concentrations of intracellular copper. Moreover, these investigators made the unexpected discovery that there is less than one atom of free copper per cell. A Perspective by Lippard comments on these findings and their implications for human diseases that involve dysregulation of transition metal ion intracellular concentrations or mutations in SOD1.

Stephen J. Lippard (Massachusetts Institute of Technology;Department of Chemistry)

1999-04-30

276

21 CFR 73.2647 - Copper powder.  

Code of Federal Regulations, 2010 CFR

...GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION...specifications. The color additive copper powder shall conform...amounts consistent with good manufacturing practice. (c) Labeling. The color additive and any mixture...

2010-04-01

277

Molecular dynamics simulation of polycrystalline copper  

NASA Astrophysics Data System (ADS)

An approach for molecular dynamics simulation of the formation of polycrystalline materials from a melt during its cooling is proposed. Atomic configurations of copper corresponding to polycrystals with the mean grain size from 2 to 16 nm are obtained. Isothermal uniaxial tension and compression of these polycrystals is studied by the molecular dynamics method. For the mean grain size of polycrystalline copper being smaller than 10 nm, it is shown that Young's modulus and yield stress decrease as the grain size decreases. Shock adiabats for polycrystalline copper are constructed. For a material with the grain size approximately equal to 2 nm, the temperature behind the shock wave front is demonstrated to be 10% higher than that in a polycrystal with the grain size greater than 10 nm. Molecular dynamics calculations predict the presence of copper with a body-centered cubic lattice behind the shock wave front at pressures ranging from 100 to 200 GPa.

Bolesta, A. V.; Fomin, V. M.

2014-09-01

278

Disturbed Copper Bioavailability in Alzheimer's Disease  

PubMed Central

Recent data from in vitro, animal, and human studies have shed new light on the positive roles of copper in many aspects of AD. Copper promotes the non-amyloidogenic processing of APP and thereby lowers the A? production in cell culture systems, and it increases lifetime and decreases soluble amyloid production in APP transgenic mice. In a clinical trial with Alzheimer patients, the decline of A? levels in CSF, which is a diagnostic marker, is diminished in the verum group (8?mg copper/day), indicating a beneficial effect of the copper treatment. These observations are in line with the benefit of treatment with compounds aimed at normalizing metal levels in the brain, such as PBT2. The data reviewed here demonstrate that there is an apparent disturbance in metal homeostasis in AD. More research is urgently needed to understand how this disturbance can be addressed therapeutically. PMID:22145082

Kaden, Daniela; Bush, Ashley I.; Danzeisen, Ruth; Bayer, Thomas A.; Multhaup, Gerd

2011-01-01

279

Disturbed copper bioavailability in Alzheimer's disease.  

PubMed

Recent data from in vitro, animal, and human studies have shed new light on the positive roles of copper in many aspects of AD. Copper promotes the non-amyloidogenic processing of APP and thereby lowers the A? production in cell culture systems, and it increases lifetime and decreases soluble amyloid production in APP transgenic mice. In a clinical trial with Alzheimer patients, the decline of A? levels in CSF, which is a diagnostic marker, is diminished in the verum group (8?mg copper/day), indicating a beneficial effect of the copper treatment. These observations are in line with the benefit of treatment with compounds aimed at normalizing metal levels in the brain, such as PBT2. The data reviewed here demonstrate that there is an apparent disturbance in metal homeostasis in AD. More research is urgently needed to understand how this disturbance can be addressed therapeutically. PMID:22145082

Kaden, Daniela; Bush, Ashley I; Danzeisen, Ruth; Bayer, Thomas A; Multhaup, Gerd

2011-01-01

280

Electrolytic remediation of chromated copper arsenate wastes  

E-print Network

While chromated copper arsenate (CCA) has proven to be exceptionally effective in protecting wood from rot and infestation, its toxic nature has led to the problem of disposal of CCA-treated lumber and remediation of waters ...

Stern, Heather A. G. (Heather Ann Ganung)

2006-01-01

281

Copper-Catalyzed Trifluoromethylation of Unactivated Olefins  

E-print Network

Activating the inactive: A copper-catalyzed allylic trifluoromethylation of unactivated terminal olefins proceeds under mild conditions to produce linear allylic trifluoromethylated products with high E/Z selectivity (see ...

Parsons, Andrew T.

282

Electroless Copper Deposition: A Sustainable Approach  

NASA Astrophysics Data System (ADS)

A sustainable electroless copper coating process was developed for plating automotive fasteners shaped from AISI 9255 low carbon, high silicon steel. The objective was to minimize the ionic and organic species present in each step of the plating process. A sulfuric acid solution inhibited with quinine was defined to clean the steel prior to plating. The corrosivity of the solution was examined through electrochemical and weight loss measurements to evaluate the efficiency of the cleaning process at high temperatures and high acid concentrations. An electroless copper coating process was then developed using a simple copper sulfate chemistry inhibited with quinine to extend the possible operating window. Finally, benzotriazole was evaluated as a possible anti-oxidant coating. Accelerated thioacetamide corrosion tests were used to evaluate the corrosion inhibition of benzotriazole on copper coatings.

Kutnahorsky, Marika Renee

283

21 CFR 184.1261 - Copper sulfate.  

Code of Federal Regulations, 2012 CFR

...occurs as large, deep blue or ultramarine, triclinic crystals; as blue granules, or as a light blue powder. The ingredient is prepared by the reaction of sulfuric acid with cupric oxide or with copper metal. (b) The ingredient must...

2012-04-01

284

21 CFR 184.1261 - Copper sulfate.  

Code of Federal Regulations, 2013 CFR

...occurs as large, deep blue or ultramarine, triclinic crystals; as blue granules, or as a light blue powder. The ingredient is prepared by the reaction of sulfuric acid with cupric oxide or with copper metal. (b) The ingredient must...

2013-04-01

285

21 CFR 184.1261 - Copper sulfate.  

Code of Federal Regulations, 2011 CFR

...occurs as large, deep blue or ultramarine, triclinic crystals; as blue granules, or as a light blue powder. The ingredient is prepared by the reaction of sulfuric acid with cupric oxide or with copper metal. (b) The ingredient must...

2011-04-01

286

Nanoscale Growth Twins in Sputtered Copper Films  

E-print Network

copper films are synthesized on HF etched Si (110) substrates. These films show high hardness (~ 2.8 GPa) due to high density of coherent twin boundaries (CTBs) which effectively block the motion of dislocations similar to grain boundaries (GBs...

Anderoglu, Osman

2011-08-08

287

Characterizations of severely deformed and annealed copper  

E-print Network

The objectives of this study were to characterize severely plastically deformed and recrystallized oxygen free high conductivity copper, to determine texture transformation potential of Equal Channel Angular Extrusion (ECAE) and to investigate...

Haouaoui, Mohammed

2012-06-07

288

Copper staves in the blast furnace  

SciTech Connect

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 the MAN GHH copper staves do not experience large temperature fluctuations and that the hot face temperatures will be below 250 F. This suggests that the copper staves maintain a more stable accretion layer than the cast iron staves. Contrary to initial expectations, heat flux to the copper staves is 50% lower than that to cast iron staves. The more stable accretion layer acts as an excellent insulator for the stave and greatly reduces the number of times the hot face of the stave is exposed to the blast furnace process and should result in a more stable furnace operation. In the future, it may be unnecessary to use high quality, expensive refractories in front of copper staves because of the highly stable accretion layer that appears to rapidly form due to the lower operating temperature of the staves. There is a balance of application regions for cast iron and copper staves that minimizes the capital cost of a blast furnace reline and provides an integrated cooling system with multiple campaign life potential. Cast iron staves are proven cooling elements that are capable of multiple campaign life in areas of the blast furnace which do not experience extreme heat loads. Copper staves are proving to be an effective and reliable blast furnace cooling element that are subject to virtually no wear and are projected to have a longer campaign service life in the areas of highest thermal load in the blast furnace.

Helenbrook, R.G. [ATSI, Inc., Amherst, NY (United States); Kowalski, W. [Thyssen Stahl AG, Duisburg (Germany); Grosspietsch, K.H. [Preussag Stahl AG, Saltzgitter (Germany); Hille, H. [MAN GHH AG, Oberhausen (Germany)

1996-08-01

289

COPPER LEADFRAME ANALYSIS USING THERMOMECHANICAL APPROACH  

Microsoft Academic Search

The use of copper-based structure leadframes in QFN is proven effective by three dimensional stacked-die. QFN packages in 3D Stacked-die structures take preference on the use of this leadframe design, a thick leadframe up to twice as thick as their leads thickness. Reducing the copper thickness is understood to present various thermal and reliability failure mode and mechanisms, such as

S. Abdullah; M. F. Abdullah; A. K. Ariffin; S. Yusof; R. Daud; Z. A. Aziz

2008-01-01

290

Ecophysiological tolerance of duckweeds exposed to copper  

Microsoft Academic Search

Although essential for plants, copper can be toxic when present in supra-optimal concentrations. Metal polluted sites, due to their extreme conditions, can harbour tolerant species and\\/or ecotypes. In this work we aimed to compare the physiological responses to copper exposure and the uptake capacities of two species of duckweed, Lemna minor (Lm(EC1)) and Spirodela polyrrhiza (SP), from an abandoned uranium

Myriam Kanoun-Boulé; Joaquim A. F. Vicente; Cristina Nabais; M. N. V. Prasad; Helena Freitas

2009-01-01

291

Bioaccumulation of copper by Trichoderma viride  

Microsoft Academic Search

Studies were carried out on interaction of Trichoderma viride with copper and reports bioaccumulation as a mechanism of copper tolerance during growth. There was a marked increase in the lag phase of the growth, which was concentration dependent. At a concentration of 100mg\\/L of CuCl2·2H2O, 81% of Cu(II) were removed by 3.4g\\/L of the biomass in 72h. The process was

Purnima Anand; Jasmine Isar; Saurabh Saran; Rajendra Kumar Saxena

2006-01-01

292

Adsorption of Copper at Aqueous Illite Surfaces  

Microsoft Academic Search

In this paper, we conducted potentiometric titrations, batch adsorption experiments and FT-IR analysis to study the uptake of copper in illite\\/water suspensions and then applied the constant capacitance surface complexation model to interpret the reaction mechanism at the aqueous illite surfaces. Our research shows that the copper adsorption at these surfaces is strongly dependent on pH and that the adsorption

Qing Du; Zhongxi Sun; Willis Forsling; Hongxiao Tang

1997-01-01

293

Methane combustion over copper chromite catalysts  

Microsoft Academic Search

A study of the activity and durability of two different copper chromite catalysts in methane combustion is presented. The\\u000a catalysts, a massive (CAT-E) and a supported (CAT-I) copper chromite, were characterized by different techniques in order\\u000a to investigate morphological properties (N2 adsorption), crystalline structure (X-ray diffraction, XRD) and surface composition (X-ray photoelectron spectroscopy, XPS).\\u000a Among the different crystalline phases identified,

G. Comino; A. Gervasini; V. Ragaini; Z. R. Ismagilov

1997-01-01

294

Electrical Transport in Copper and Cobalt Ferricyanides  

Microsoft Academic Search

Copper and cobalt ferricyanides are found to be electrical conductors. The temperature variation of their resistivities are studied. It is found that the activa- tion energy of copper ferricyanide is 0.23 eV provided the sample is not heated above 118°C. If the sample is heated above 118°C a partial chemical degradation of the con~pound transforms the activation energy to 1.43

K. TENNAKONE

295

40 CFR 421.40 - Applicability: Description of the primary copper smelting subcategory.  

Code of Federal Regulations, 2012 CFR

...Applicability: Description of the primary copper smelting subcategory...NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Primary Copper Smelting Subcategory ...Applicability: Description of the primary copper smelting...

2012-07-01

296

Adsorption of copper at aqueous illite surfaces  

SciTech Connect

In this paper, the authors conducted potentiometric titrations, batch adsorption experiments and FT-IR analysis to study the uptake of copper in illite/water suspensions and then applied the constant capacitance surface complexation model to interpret the reaction mechanism at the aqueous illite surfaces. This research shows that the copper adsorption at these surfaces is strongly dependent on pH and that the adsorption causes a deprotonation of surface groups. The authors propose that the uptake of copper in the carbonate-free illite suspensions can be explained by the formation of mononuclear surface complexes, {triple_bond}SOCu{sup +} and {triple_bond}SOCuOH, and a multinuclear surface complex, {triple_bond}SOCu{sub 2}(OH){sub 2}{sup +}, followed by the formation of a bulk precipitate, Cu(OH){sub 2}(s), or a surface precipitate, {triple_bond}SOCu{sub 2}(OH){sub 3}(sp). For the illite suspensions containing carbonates, the authors propose that the copper-illite interaction can be depicted by the formation of mononuclear surface complexes, {triple_bond}SOCu{sup +} and {triple_bond}SOCuOH, followed by the formation of a copper hydroxylcarbonate precipitate, Cu{sub 2}(OH){sub 2}CO{sub 3}(s), rather than a copper hydroxide precipitate. The existence of Cu{sub 2}(OH){sub 2}CO{sub 3}(s) in the carbonate-containing illite suspensions was identified by FT-IR analysis.

Du, Q. [Luleaa Univ. of Technology (Sweden). Div. of Inorganic Chemistry] [Luleaa Univ. of Technology (Sweden). Div. of Inorganic Chemistry; [Academia Sinica, Beijing (China). Research Center for Eco-Environmental Sciences; Sun, Z.; Forsling, W. [Luleaa Univ. of Technology (Sweden). Div. of Inorganic Chemistry] [Luleaa Univ. of Technology (Sweden). Div. of Inorganic Chemistry; Tang, H. [Academia Sinica, Beijing (China). Research Center for Eco-Environmental Sciences] [Academia Sinica, Beijing (China). Research Center for Eco-Environmental Sciences

1997-03-01

297

Method for providing uranium with a protective copper coating  

DOEpatents

The present invention is directed to a method for providing uranium metal with a protective coating of copper. Uranium metal is subjected to a conventional cleaning operation wherein oxides and other surface contaminants are removed, followed by etching and pickling operations. The copper coating is provided by first electrodepositing a thin and relatively porous flash layer of copper on the uranium in a copper cyanide bath. The resulting copper-layered article is then heated in an air or inert atmosphere to volatilize and drive off the volatile material underlying the copper flash layer. After the heating step an adherent and essentially non-porous layer of copper is electro-deposited on the flash layer of copper to provide an adherent, multi-layer copper coating which is essentially impervious to corrosion by most gases.

Waldrop, Forrest B. (Powell, TN); Jones, Edward (Knoxville, TN)

1981-01-01

298

Phototunable Magnetism in Copper Octacyanomolybdate  

PubMed Central

We introduce copper molybdenum cyanides of general formula Cu2[Mo(CN)8]·nH2O, which can serve as optofunctional magnetic devices. Their ground states generally stay paramagnetic down to temperatures of the K order but exhibit a spontaneous magnetization upon photoirradiation usually below a few tens of K. To interest us still further, such a ferromagnetic stateinduced by blue-laser irradiation is demagnetized step by step through further application of red or near-infrared laser pulses. We solve this intriguing photomagnetism. The ground-state properties are fully revealed by means of a group-theoretical technique. Taking account of experimental observations, we simulate applying pump laser pulses to a likely ground state and successfully reproduce both the magnetization and demagnetization dynamics. We monitor the photorelaxation process through angle-resolved photoemission spectroscopy. Electrons are fully itinerant in any of the photoinduced steady states, forming a striking contrast to the initial equilibrium state of atomic aspect. The fully demagnetized final steady state looks completely different from the initial paramagnetism but bears good analogy to one of the possible ground states available with the Coulomb repulsion on Cu sites suppressed. PMID:24895661

Ohara, Jun

2014-01-01

299

Heme/copper terminal oxidases  

SciTech Connect

Spatially well-organized electron-transfer reactions in a series of membrane-bound redox proteins form the basis for energy conservation in both photosynthesis and respiration. The membrane-bound nature of the electron-transfer processes is critical, as the free energy made available in exergonic redox chemistry is used to generate transmembrane proton concentration and electrostatic potential gradients. These gradients are subsequently used to drive ATP formation, which provides the immediate energy source for constructive cellular processes. The terminal heme/copper oxidases in respiratory electron-transfer chains illustrate a number of the thermodynamic and structural principles that have driven the development of respiration. This class of enzyme reduces dioxygen to water, thus clearing the respiratory system of low-energy electrons so that sustained electron transfer and free-energy transduction can occur. By using dioxygen as the oxidizing substrate, free-energy production per electron through the chain is substantial, owing to the high reduction potential of O{sub 2} (0.815 V at pH 7). 122 refs.

Ferguson-Miller, S.; Babcock, G.T. [Michigan State Univ., East Lansing, MI (United States)] [Michigan State Univ., East Lansing, MI (United States)

1996-11-01

300

Copper-mediated LDL oxidation by homocysteine and related compounds depends largely on copper ligation  

E-print Network

Copper-mediated LDL oxidation by homocysteine and related compounds depends largely on copper 2003; accepted 31 October 2003 Abstract Oxidation of low-density lipoprotein (LDL) is thought factor for atherosclerosis, and may act through LDL oxidation, although this is controversial

Williamson, Mike P.

301

Exclusion of copper from altered hepatocytes in white perch (Morone americana) with hepatic copper storage.  

PubMed

Iron is excluded from foci of hepatocellular alteration in carcinogenesis of rodents and some fish. Among white perch (Morone americana), there is a condition of hepatic copper storage in which copper-loaded livers are produced naturally. In a group of fish collected from the Chesapeake Bay, Maryland (USA), from September to December 1990, we observed hepatic lesions which excluded copper similar to the phenomenon of iron exclusion, in a white perch with over 3,600 micrograms/g wet weight hepatic copper. The lesions were of two types: one with cells morphologically different from normal hepatocytes and which had diminished to absolute exclusion of copper with the copper specific histochemical stain rubeinic acid, and a second with cells morphologically similar to normal hepatocytes which had only a partial exclusion of copper. Although the exact cause and nature of the lesions was not determined, intrinsic copper toxicity, environmental pollution, or a combination of these factors may have contributed to their development. PMID:7563436

Bunton, T E

1995-01-01

302

Putting copper into action: copper-impregnated products with potent biocidal activities.  

PubMed

Copper ions, either alone or in copper complexes, have been used for centuries to disinfect liquids, solids, and human tissue. Today copper is used as a water purifier, algaecide, fungicide, nematocide, molluscicide, and antibacterial and antifouling agent. Copper also displays potent antiviral activity. We hypothesized that introducing copper into clothing, bedding, and other articles would provide them with biocidal properties. A durable platform technology has been developed that introduces copper into cotton fibers, latex, and other polymeric materials. This study demonstrates the broad-spectrum antimicrobial (antibacterial, antiviral, antifungal) and antimite activities of copper-impregnated fibers and polyester products. This technology enabled the production of antiviral gloves and filters (which deactivate HIV-1 and other viruses), antibacterial self-sterilizing fabrics (which kill antibiotic-resistant bacteria, including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococci), antifungal socks (which alleviate symptoms of athlete's foot), and anti-dust mite mattress covers (which reduce mite-related allergies). These products did not have skin-sensitizing properties, as determined by guine pig maximization and rabbit skin irritation tests. Our study demonstrates the potential use of copper in new applications. These applications address medical issues of the greatest importance, such as viral transmissions; nosocomial, or healthcare-associated, infections; and the spread of antibiotic-resistant bacteria. PMID:15345689

Borkow, Gadi; Gabbay, Jeffrey

2004-11-01

303

Non-enzymic copper reduction by menaquinone enhances copper toxicity in Lactococcus lactis IL1403.  

PubMed

Lactococcus lactis possesses a pronounced extracellular Cu(2+)-reduction activity which leads to the accumulation of Cu(+) in the medium. The kinetics of this reaction were not saturable by increasing copper concentrations, suggesting a non-enzymic reaction. A copper-reductase-deficient mutant, isolated by random transposon mutagenesis, had an insertion in the menE gene, which encodes O-succinylbenzoic acid CoA ligase. This is a key enzyme in menaquinone biosynthesis. The ?menE mutant was deficient in short-chain menaquinones, and exogenously added menaquinone complemented the copper-reductase-deficient phenotype. Haem-induced respiration of wild-type L. lactis efficiently suppressed copper reduction, presumably by competition by the bd-type quinol oxidase for menaquinone. As expected, the ?menE mutant was respiration-deficient, but could be made respiration-proficient by supplementation with menaquinone. Growth of wild-type cells was more copper-sensitive than that of the ?menE mutant, due to the production of Cu(+) ions by the wild-type. This growth inhibition of the wild-type was strongly attenuated if Cu(+) was scavenged with the Cu(I) chelator bicinchoninic acid. These findings support a model whereby copper is non-enzymically reduced at the membrane by menaquinones. Respiration effectively competes for reduced quinones, which suppresses copper reduction. These findings highlight novel links between copper reduction, respiration and Cu(+) toxicity in L. lactis. PMID:23579688

Abicht, Helge K; Gonskikh, Yulia; Gerber, Simon D; Solioz, Marc

2013-06-01

304

Copper intake and health threat by consuming seafood from copper-contaminated coastal environments in Taiwan  

SciTech Connect

The purpose of this paper is to describe the impact of copper pollution on the main aquaculture coast of Taiwan and the potential risk from eating the green oysters cultured along the polluted coast. The data show that the highest average concentration of copper in oysters was observed in the Erhjin Chi estuary from 1986 to 1990. The copper concentration in both the seawater and the sediment collected along the Erhjin Chi estuary was also the highest in all sampling locations. Copper concentration in oysters collected from Erhjin Chi, Hsiangshan, and Anping from 1988 to 1990 was, respectively, 61, 29, and 22 times higher than that of 10 years ago. The potential frisk from consuming oysters is relatively higher than that of other seafoods due the high bioaccumulation of oysters. The oysters in the Erhjin Chi estuary had an average concentration of copper of 3,075 [+-] 826 [mu]g/g during the past three years (1988--1990). The average copper intake from oysters for an adult with 70 kg body weight was 12.6 mg/d. The estimate indicated that the average copper intake from the oysters for female individuals is 14 times more than that of international limits. Based on the average value, long-term intake of copper through consumption of oysters cultured along the Erhjin Chi estuary be critical, especially for some high-risk groups.

Han, B.C. (Taipei Medical Coll. (Taiwan, Province of China). School of Public Health); Jeng, W.L.; Hung, T.C. (National Taiwan Univ., Taipei (Taiwan, Province of China). Inst. of Oceanography); Jeng, M.S. (Academia Sinica, Taipei (Taiwan, Province of China). Inst. of Zoology)

1994-05-01

305

One-step brazing process to join CFC composites to copper and copper alloy  

NASA Astrophysics Data System (ADS)

The aim of this work is to develop a new single-step brazing technique to join carbon fibre reinforced carbon composite (CFC) to pure copper (Cu) and copper alloy (CuCrZr) for nuclear fusion applications. In order to increase the wettability of CFC by a copper-based brazing alloy containing no active metal, the composite surface was modified by direct reaction with chromium, which forms a carbide layer and allows a large reduction of the contact angle. After the CFC surface modification, the commercial Gemco ® alloy (Cu/Ge) was successfully used to braze CFC to pure copper and pure copper to CuCrZr by the same heat treatment. The shear strength of the CFC/Cu joints measured by single lap shear tests at room temperature was (34 ± 4) MPa, comparable to the values obtained by other joining processes and higher than the intrinsic CFC shear strength.

Salvo, Milena; Casalegno, Valentina; Rizzo, Stefano; Smeacetto, Federico; Ferraris, Monica; Merola, Mario

2008-02-01

306

Enhanced ATP-dependent copper efflux across the root cell plasma membrane in copper-tolerant Silene vulgaris.  

PubMed

We studied copper uptake in inside-out plasma membrane vesicles derived from roots of copper-sensitive, moderately copper-tolerant and highly copper-tolerant populations of Silene vulgaris (Amsterdam, Marsberg and Imsbach, respectively). Plasma membrane vesicles were isolated using the two-phase partitioning method and copper efflux was measured using direct filtration experiments. Vesicles derived from Imsbach plants accumulated two and three times more copper than those derived from Marsberg and Amsterdam plants, respectively. This accumulation was ATP-dependent. Also, 9-amino-6-chloro-2-methoxyacridine fluorescence quenching rates upon copper addition decreased in the order Imsbach>Marsberg>Amsterdam. Our results support the hypothesis that efflux of copper across the root plasma membrane plays a role in the copper tolerance mechanism in S. vulgaris. PMID:12060300

Van Hoof, Nathalie A. L. M.; Koevoets, Paul L. M.; Hakvoort, Henk W. J.; Ten Bookum, Wilma M.; Schat, Henk; Verkleij, Jos A. C.; Ernst, Wilfried H. O.

2001-10-01

307

Structure and Relaxation in Germanium Selenide and Arsenic Selenide Glasses  

NASA Astrophysics Data System (ADS)

GexSe1- x and AsxSe1- x glasses have found use in many technological applications due to their excellent rheological properties and their wide IR transparency window. However, the low glass transition temperatures of these glasses leads to large changes in their properties, due to structural relaxation, over the weeks and months subsequent to their fabrication. Thus, obtaining a more thorough understanding of structural relaxation and its relation to the structure, composition, and processing of these glasses is important in furthering their use. Structural investigations, using NMR and Raman spectroscopies, performed on the GexSe1-x family of glasses show that the structure of these glasses is composed of two distinct microdomains. One corresponds to a rigid GeSe2-like domain and the other corresponds to a floppy Se domain. These results are compared to other existing structural models for GexSe 1-x glasses. Enthalpy measurements on both GeSe9 and GeSe4 optical fibers which were aged up to five years demonstrate that both compositions undergo a large amount of enthalpy relaxation in this time period. Raman spectroscopy performed concurrently with enthalpy measurements on the same GeSe9 and GeSe4 fibers shows that one of the structural changes taking place within the glass network is the conversion of edge-sharing to corner-sharing tetrahedra in the GeSe2-like phase. Moreover, the rate at which this conversion takes place is shown to be similar to the rate of enthalpy relaxation, suggesting that this structural change is one of the main mechanisms for structural relaxation in GexSe1- x glasses. Implementation of the Tool-Narayanaswamy-Moynihan (TNM) model as a hybrid computer model allowing the prediction of the four relaxation parameters Delta h*, log(A), x, and beta via optimization of simulated and experimental data was accomplished. It was found that a multi-rate version of the TNM model, which obtains an average set of model parameters via optimization of multiple experimental thermal histories simultaneously, was able to predict relaxation parameters for AsxSe 1-x glasses within the 2.10 ? < r> ? 2.50 compositional domain, where is the average bond coordination of the glass network as defined by the Phillips and Thorpe constraints model. Above = 2.50, however, the model fails, due to a bimodal distribution of relaxation times within the glass structure contrary to the TNM model assumption of a unimodal distribution of relaxation times, thus rendering the model inapplicable. Muti-rate modeling of the GexSe1- x family of glasses was also attempted, however the TNM model also fails for this family of glasses due to the inherently bimodal distribution of relaxation times which arises from their bimodal structure.

King, Ellen Anne

308

Copper in microbial pathogenesis: meddling with the metal  

PubMed Central

Transition metals such as iron, zinc, copper and manganese are essential for the growth and development of organisms ranging from bacteria to mammals. Numerous studies have focused on the impact of iron availability during bacterial and fungal infections, and increasing evidence suggests that copper is also involved in microbial pathogenesis. Not only is copper an essential co-factor for specific microbial enzymes, but several recent studies also strongly suggest that copper is used to restrict pathogen growth in vivo. Here, we review evidence that animals use copper as an anti-microbial weapon and, in turn, microbes have developed mechanisms to counteract the toxic effects of copper. PMID:22341460

Samanovic, Marie I.; Ding, Chen; Thiele, Dennis J.; Darwin, K. Heran

2012-01-01

309

Copper and oxidative stress in the pathogenesis of Alzheimer's disease.  

PubMed

Copper is a redox-active metal with many important biological roles. Consequently, its distribution and oxidation state are subject to stringent regulation. A large body of clinicopathological, circumstantial, and epidemiological evidence suggests that the dysregulation of copper is intimately involved in the pathogenesis of Alzheimer's disease. Other light transition metals such as iron and zinc may affect copper regulation by competing for copper binding sites and transporters. Therapeutic interventions targeting the regulation of copper are promising, but large gaps in our understanding of copper biochemistry, amyloidogenesis, and the nature of oxidative stress in the brain must be addressed. PMID:22708607

Eskici, Gözde; Axelsen, Paul H

2012-08-14

310

Syntheses, structures, and optical properties of the indium/germanium selenides Cs4In8GeSe16, CsInSe2, and CsInGeSe4  

NASA Astrophysics Data System (ADS)

The three solid-state indium/germanium selenides Cs4In8GeSe16, CsInSe2, and CsInGeSe4 have been synthesized at 1173 K. The structure of Cs4In8GeSe16 is a three-dimensional framework whereas those of CsInSe2 and CsInGeSe4 comprise sheets separated by Cs cations. Both Cs4In8GeSe16 and CsInGeSe4 display In/Ge disorder. From optical absorption measurements these compounds have band gaps of 2.20 and 2.32 eV, respectively. All three compounds are charge balanced.

Ward, Matthew D.; Pozzi, Eric A.; Van Duyne, Richard P.; Ibers, James A.

2014-04-01

311

75 FR 26098 - Safety Zone; Under Water Clean Up of Copper Canyon, Lake Havasu, AZ  

Federal Register 2010, 2011, 2012, 2013

...Safety Zone; Under Water Clean Up of Copper Canyon...sponsoring the Under Water Copper Canyon Clean up, which will involve...zone; Copper Canyon Clean Up, Lake Havasu, AZ...zone will include all waters of Copper Canyon...

2010-05-11

312

Microvascular responses in copper-deficient rats  

SciTech Connect

In this study on copper deficiency, the rat crewmaster microcirculation was used as a model for endogenous histamine release and platelet thrombi formation. Male Sprague-Dawley rats were fed either a copper-supplemented diet (CuS, 5 ppm) or a copper-deficient diet (CuD, 0 ppm) for 5 wk before experimentation. The crewmasters of anesthetized rats were spread in a Krebs-filed tissue bath. In venules of CuS animals, photoactivation of intravascular fluorescein isothiocyanate tagged to bovine serum albumin caused significant platelet aggregation and reduction of red blood cell column diameter (RBCCD) by 40 min and stasis of flow by 60 min. In CuD animals there was only minor platelet aggregation and no reduction in RBCCD. Platelet aggregometry studies did not demonstrate reduced platelet aggregation in the CuD group, suggesting that copper deficiency alters the endothelium to inhibit adhesion. Compound 48/80 (1.0 and 10.0 microgram/ml) induced macromolecular leakage in both CuS and CuD groups, with the response in the CuD animals being significantly greater. The results demonstrate that copper deficiency results in alterations of the regulatory mechanisms governing inflammation and thrombosis.

Schuschke, D.A.; Saari, J.T.; Ackermann, D.M.; Miller, F.N. (Univ. of Louisville School of Medicine, KY (USA))

1989-11-01

313

Sol-gel-derived percolative copper film  

SciTech Connect

Cu-SiO{sub 2} films were prepared by the sol-gel method. Two-dimensional fractal copper films were formed after the films were thermally treated in reducing atmosphere. dc resistances of the films decrease 12 orders of magnitude as the content of copper increases from 70 to 80 mol%. During the resistance measurement under argon atmosphere, samples showed a sharp increase or decrease of resistance at a transition temperature which is ascribed to the oxidation of Cu into CuO. The oxidation was also observed in the in situ high temperature X-ray diffraction under vacuum condition. The evolution of the morphology of the films was studied by scanning electron microscopy. As the content of copper increases, the forms of copper particles change from discrete to aggregate then to interconnecting. The coverage coefficients of the copper range from 23 to 55% and the fractal dimensions range from 1.65 to 1.77. The percolation thresholds for the coverage coefficient and the fractal dimension are about 33% and 1.71, respectively, which corresponds to the sample containing 72.5 mol% of Cu.

Szu Sungping [Department of Physics, National Chung-Hsing University, Taichung 402, Taiwan (China)], E-mail: spszu@phys.nchu.edu.tw; Cheng, C.-L. [Department of Physics, National Chung-Hsing University, Taichung 402, Taiwan (China)

2008-10-02

314

The effect of temperature and salinity on copper body-burden and copper toxicity to Hediste (Nereis) diversicolor.  

PubMed

Temperature from 12 to 22°C and salinity from 30.5 to 7.6‰ increased accumulation of copper in Hediste diversicolor. Copper accumulated ranged from 85.83 to 217.14 ?g g(-1). Sediments reduced accumulation of copper under temperature-salinity combinations. Accumulated copper ranged from 90.19 to 153.26 ?g g(-1).However, mortality of the worms was not solely dependent upon copper body-burden. It ranged from 34 to 45% and from 38 to 80% in the presence of sediment. A combination of osmoregulatory and thermal stresses increased the toxic effect of copper to the worms. PMID:24234340

Ozoh, P T

1992-04-01

315

Thermoelectric Properties of Selenides Spinels  

NASA Technical Reports Server (NTRS)

Many compounds with the spinel structure type have been analyzed for their thermoelectric properties. Published data was used to augment experimental results presented here to select promising thermoelectric spinels.

Snyder, G.; Caillat, T.; Fleurial, J-P.

2000-01-01

316

Energetics of copper trafficking between the Atx1 metallochaperone and the intracellular copper transporter, Ccc2.  

PubMed

The Atx1 metallochaperone protein is a cytoplasmic Cu(I) receptor that functions in intracellular copper trafficking pathways in plants, microbes, and humans. A key physiological partner of the Saccharomyces cerevisiae Atx1 is Ccc2, a cation transporting P-type ATPase located in secretory vesicles. Here, we show that Atx1 donates its metal ion cargo to the first N-terminal Atx1-like domain of Ccc2 in a direct and reversible manner. The thermodynamic gradient for metal transfer is shallow (K(exchange) = 1.4 +/- 0.2), establishing that vectorial delivery of copper by Atx1 is not based on a higher copper affinity of the target domain. Instead, Atx1 allows rapid metal transfer to its partner. This equilibrium is unaffected by a 50-fold excess of the Cu(I) competitor, glutathione, indicating that Atx1 also protects Cu(I) from nonspecific reactions. Mechanistically, we propose that a low activation barrier for transfer between partners results from complementary electrostatic forces that ultimately orient the metal-binding loops of Atx1 and Ccc2 for formation of copper-bridged intermediates. These thermodynamic and kinetic considerations suggest that copper trafficking proteins overcome the extraordinary copper chelation capacity of the eukaryotic cytoplasm by catalyzing the rate of copper transfer between physiological partners. In this sense, metallochaperones work like enzymes, carefully tailoring energetic barriers along specific reaction pathways but not others. PMID:10764731

Huffman, D L; O'Halloran, T V

2000-06-23

317

Effect of zinc on copper and iron bioavailability as influenced by dietary copper and fat source  

SciTech Connect

In a number of experiments, they have observed that liver copper levels of young male rats fed low zinc diets were essentially the same as liver copper levels of rats fed adequate zinc. Liver iron levels of rats fed low zinc diets, however, tended to be markedly higher than liver iron levels of rats fed adequate zinc. Increases in dietary zinc (up to 200 ppm) were generally associated with decreases in liver iron deposition, but had little effect on liver copper deposition. Iron bioavailability appeared to be enhanced when fat sources high in saturated fatty acids were used, and there was evidence that the type of dietary fat influenced the effect of zinc on iron bioavailability. Liver copper deposition, however, did not appear to be markedly affected by the type of dietary fat suggesting that copper bioavailability is less affected by fat source. Increases in dietary copper were associated with increases in liver copper levels and decreases in liver iron levels of rats fed increasing levels of zinc. These data suggest that potential interrelationships between dietary factors not being considered as experimental variables could have significant effects on results and on the interrelationships between dietary variables which are being studied.

Magee, A.C.; Jones, B.P.; Lin, F.; Sinthusek, G.; Frimpong, N.A.; Wu, S.

1986-03-05

318

Metallic copper corrosion rates, moisture content, and growth medium influence survival of copper-ion resistant bacteria  

PubMed Central

The rapid killing of various bacteria in contact with metallic copper is thought to be influenced by influx of copper ions into the cells but the exact mechanism is not fully understood. This study showed that the kinetics of contact-killing of copper surfaces depended greatly on the amount of moisture present, copper content of alloys, type of medium used, and type of bacteria. We examined antibiotic- and copper-ion resistant strains of Escherichia coli and Enterococcus faecium isolated from pig farms following the use of copper sulfate as feed supplement. The results showed rapid killing of both copper-ion resistant E. coli and E. faecium strains when samples in rich medium were spread in a thin, moist layer on copper alloys with 85% or greater copper content. E. coli strains were rapidly killed under dry conditions while E. faecium strains were less affected. Electroplated copper surface corrosion rates were determined from electro-chemical polarization tests using the Stern-Geary method and revealed decreased corrosion rates with benzotriazole and thermal oxide coating. Copper-ion resistant E. coli and E. faecium cells suspended in 0.8% NaCl showed prolonged survival rates on electroplated copper surfaces with benzotriazole coating and thermal oxide coating compared to surfaces without anti-corrosion treatment. Control of surface corrosion affected the level of copper ion influx into bacterial cells which contributed directly to bacterial killing. PMID:21085951

Elguindi, Jutta; Moffitt, Stuart; Hasman, Henrik; Andrade, Cassandra; Raghavan, Srini; Rensing, Christopher

2013-01-01

319

Protective coating for copper in aluminum heat exchangers  

NASA Technical Reports Server (NTRS)

Application of ultrathin layer of molybdenum disulfied coating to copper tubing permits utilization of tubing in cast-aluminum heat exchangers. Coating prevents formation of copper/aluminum eutectic, but does not impede heat transfer.

Avazian, R.

1978-01-01

320

Pathogenic adaptations to host-derived antibacterial copper  

PubMed Central

Recent findings suggest that both host and pathogen manipulate copper content in infected host niches during infections. In this review, we summarize recent developments that implicate copper resistance as an important determinant of bacterial fitness at the host-pathogen interface. An essential mammalian nutrient, copper cycles between copper (I) (Cu+) in its reduced form and copper (II) (Cu2+) in its oxidized form under physiologic conditions. Cu+ is significantly more bactericidal than Cu2+ due to its ability to freely penetrate bacterial membranes and inactivate intracellular iron-sulfur clusters. Copper ions can also catalyze reactive oxygen species (ROS) generation, which may further contribute to their toxicity. Transporters, chaperones, redox proteins, receptors and transcription factors and even siderophores affect copper accumulation and distribution in both pathogenic microbes and their human hosts. This review will briefly cover evidence for copper as a mammalian antibacterial effector, the possible reasons for this toxicity, and pathogenic resistance mechanisms directed against it. PMID:24551598

Chaturvedi, Kaveri S.; Henderson, Jeffrey P.

2014-01-01

321

Biotransference and biomagnification of selenium copper, cadmium, zinc, arsenic and  

E-print Network

Biotransference and biomagnification of selenium copper, cadmium, zinc, arsenic and lead the biotransference of selenium copper, cadmium, zinc, arsenic and lead was measured in a contaminated seagrass. Selenium was found to biomagnify, exceeding maximum permitted concentrations for human consumption within

Canberra, University of

322

COPPER-COATED CONTAINERS AND THEIR IMPACT ON THE ENVIRONMENT  

Microsoft Academic Search

The following statements and information address public concerns about copper in the environment. They are based on many years of research on the use of copper in agriculture and aquatic weed management and its impact on the environment.

MARK A. CRAWFORD

323

Biologic assessment of copper-containing amalgams.  

PubMed

In order to reduce creep and avoid marginal fractures in amalgam restorations, new alloys containing higher proportions of copper have been introduced. Fillings of these materials were placed in cavities prepared in the deciduous teeth of monkeys or placed in polyethylene tubes and implanted subcutaneously in rats. Conventional silver/tin alloys and zinc oxide eugenol cement were used as reference materials. Despite limitations due to the varying depths of cavities and the small number of animals involved it was concluded that the high copper alloys caused more severe pulp damage than the other materials studied. In the implantation studies many of the high copper specimens were exfoliated before the end of the experimental period. It is concluded that in deep cavities these materials require the use of a non-toxic base or lining material although as they are commonly used in young children's teeth the placement of linings and the isolation of the cavity pose problems. PMID:412793

Mjor, I A; Eriksen, H M; Haugen, E; Skogedal, O

1977-12-01

324

Growth Of Single Crystalline Copper Nanowhiskers  

SciTech Connect

Nanowhiskers are defect free single crystals with high aspect ratios and as result exhibit superior physical, e.g. mechanical properties. This paper sheds light on the kinetics of copper nanowhisker growth and thickening. Whisker growth was provoked by covering silicon wafers with a thin carbon film and subsequently coating them with copper by molecular beam epitaxy. The whiskers grown were examined by scanning electron microscopy and the length and diameter were measured as a function of the amount of copper deposited. The experiments show that nanowhisker growth follows Ruth and Hirth's growth model. A fit of the model parameters to the acquired data shows that adsorption of atoms on the substrate and on the whisker surface, with subsequent surface diffusion to the whisker tip, delivers by far the greatest portion of material for whisker growth. Additionally, the experiments demonstrate that the crystallographic orientation of the substrate surface greatly influences the growth rate in the early stage of whisker growth.

Kolb, Matthias [Institute for Materials Research, University of Stuttgart, Heisenbergstrasse 3, 70569 Stuttgart (Germany); Richter, Gunther [Max Planck Institute for Metals Research, Heisenbergstrasse 3, 70569 Stuttgart (Germany)

2010-11-24

325

Graphene-protected copper and silver plasmonics.  

PubMed

Plasmonics has established itself as a branch of physics which promises to revolutionize data processing, improve photovoltaics, and increase sensitivity of bio-detection. A widespread use of plasmonic devices is notably hindered by high losses and the absence of stable and inexpensive metal films suitable for plasmonic applications. To this end, there has been a continuous search for alternative plasmonic materials that are also compatible with complementary metal oxide semiconductor technology. Here we show that copper and silver protected by graphene are viable candidates. Copper films covered with one to a few graphene layers show excellent plasmonic characteristics. They can be used to fabricate plasmonic devices and survive for at least a year, even in wet and corroding conditions. As a proof of concept, we use the graphene-protected copper to demonstrate dielectric loaded plasmonic waveguides and test sensitivity of surface plasmon resonances. Our results are likely to initiate wide use of graphene-protected plasmonics. PMID:24980150

Kravets, V G; Jalil, R; Kim, Y-J; Ansell, D; Aznakayeva, D E; Thackray, B; Britnell, L; Belle, B D; Withers, F; Radko, I P; Han, Z; Bozhevolnyi, S I; Novoselov, K S; Geim, A K; Grigorenko, A N

2014-01-01

326

The copper chaperone Atox1 in canine copper toxicosis in Bedlington terriers.  

PubMed

Copper toxicosis, resulting in liver disease, commonly occurs in Bedlington terriers. This recessively inherited disorder, similar in many respects to Wilson disease, is of particular interest because the canine Atp7b gene, homologous to ATP7B defective in Wilson disease, is not responsible for canine copper toxicosis as has been expected. Atox1, a copper chaperone delivering copper to Atp7b, therefore became a potential candidate. We cloned canine Atox1, which shows conserved motifs of the copper-binding domain (MTCXXC) and of the lysine-rich region (KTGK), and showed 88, 80, and 41% amino acid sequence identity with the orthologous mouse, human, and yeast proteins. No gross deletions of Atox1 could be identified in the affected Bedlington terriers by Southern blot analysis of genomic DNA. The canine Atox1 gene spans about 4 kb, with a 204-bp open reading frame cDNA contained within two exons. Sequence analysis of the coding regions, including intron/exon boundaries, showed no mutations in Atox1 from genomic DNA of an affected dog. We have also identified an apparently nontranscribed canine Atox1 pseudogene, with 12 sequence changes and no intron. Mapping of Atox1 and a marker closely linked to the canine copper toxicosis locus indicated lack of synteny. Atox1 is therefore excluded as a candidate gene for canine copper toxicosis, indicating that some other unidentified gene must be responsible for this copper storage disease in dogs and also suggesting the possibility of a similar gene responsible for a copper storage disease in humans. PMID:10585777

Nanji, M S; Cox, D W

1999-11-15

327

Graphene synthesis and characterization on copper  

NASA Astrophysics Data System (ADS)

Graphene, two dimensional sheet of carbon atoms has recently gained attention as some of its properties are promising for electronics applications e.g. higher mobility that translates to higher operating frequency for devices geared towards radio frequency applications. Excellent optical transmittance combined with its semi metallic behavior makes it an important material for transparent contacts in solar cells. To bring graphene to the production level, synthesis methods are needed for its growth on wafer scale. It has been shown that chemical vapor deposition (CVD) is one of the techniques that can potentially synthesize wafer scale graphene. Recently copper has gained popularity as an important substrate material for graphene growth due to its lower carbon solubility, which allows better control over number of graphene layers. Here we report optimization of graphene growth on copper foils with our home made atmospheric pressure chemical vapor deposition (APCVD) setup. Graphene growth on copper under APCVD was non self-limiting similar to other reports. It was found that apart from growth parameters surface texture plays a very important role in graphene growth. In fact, few layer and bilayer graphene were obtained on the regions where copper surface was not uniform, confirmed by Raman spectroscopy. To improve copper surface texture thin layer of copper film was evaporated by electron beam evaporation before the graphene growth process. After this modification, monolayer graphene was obtained on areas as large as 300 microm x 300 microm confirmed by Raman area maps. Graphene transfer procedure was also optimized so that graphene on metal surface could be transferred to insulating substrate.

Mohsin, Ali

328

Pesticidal Copper (I) Oxide: Environmental Fate and Aquatic Toxicity  

Microsoft Academic Search

\\u000a Besides being a naturally occurring element and an essential micronutrient, copper is used as a pesticide, but at generally\\u000a higher concentrations. Copper, unlike organic pesticides, does not degrade, but rather enters a complex biogeochemical cycle.\\u000a In the water column, copper can exist bound to both organic and inorganic species and as free or hydrated copper ions. Water\\u000a column chemistry affects

Lina Kiaune; Nan Singhasemanon

329

Copper slag thermal storage -- projections of performance and economics  

Microsoft Academic Search

A solid residual regarded as waste from copper smelters, known as copper slag, offers an excellent medium for the storage of heat energy. Over one billion tons of slag is available at hundreds of smelters around the world. Copper slag is predominantly iron orthosilicate (2FeO.SiOâ), with sizable amounts of calcium, aluminum, magnesium and copper oxides. Formed in a highly oxidized

Curto

1984-01-01

330

Adaptation of Aerobically Growing Pseudomonas aeruginosa to Copper Starvation  

Microsoft Academic Search

Restricted bioavailability of copper in certain environments can interfere with cellular respiration because copper is an essential cofactor of most terminal oxidases. The global response of the metabolically versatile bacterium and opportunistic pathogen Pseudomonas aeruginosa to copper limitation was assessed under aerobic conditions. Expression of cioAB (encoding an alternative, copper-independent, cyanide-resistant ubiquinol oxidase) was upregulated, whereas numerous iron uptake functions

Emanuela Frangipani; Vera I. Slaveykova; Cornelia Reimmann; Dieter Haas

2008-01-01

331

Tetraalkoxyaluminates of nickel(II), copper(II), and copper(I).  

PubMed

The syntheses and structural details of tetraisopropoxyaluminates and tetra-tert-butoxyaluminates of nickel(II), copper(I), and copper(II) are reported. Within the nickel series, either Ni[Al(OiPr)4]2.2HOiPr, with nickel(II) in a distorted octahedral oxygen environment, or Ni[Al(OiPr)4]2.py, with nickel(II) in a square-pyramidal O4N coordination sphere, or Ni[(iPrO)(tBuO)3Al]2, with Ni(II) in a quasi-tetrahedral oxygen coordination, has been obtained. Another isolated complex is Ni[(iPrO)3AlOAl(OiPr)3].3py (with nickel(II) being sixfold-coordinated), which may also be described as a "NiO" species trapped by two Al(OiPr)3 Lewis acid-base systems stabilized at nickel by three pyridine donors. Copper(I) compounds have been isolated in three forms: [(iPrO)4Al]Cu.2py, [(tBuO)4Al]Cu.2py, and Cu2[(tBuO)4Al]2. In all of these compounds, the aluminate moiety behaves as a bidentate unit, creating a tetrahedrally distorted N2O2 copper environment in the pyridine adducts. In the base-free copper(I) tert-butoxyaluminate, a dicopper dumbbell [Cu-Cu 2.687(1) A] is present with two oxygen contacts on each of the copper atoms. Copper(II) alkoxyaluminates have been characterized either as Cu[(tBuO)4Al]2, {Cu(iPrO)[(iPrO)4Al]}2, and Cu[(tBuO)3(iPrO)Al]2 (copper being tetracoordinated by oxygen) or as [(iPrO)4Al]2Cu.py (pentacoordinated copper similar to the nickel derivative). Finally, a copper(II) hydroxyaluminate has been isolated, displaying pentacoordinate copper (O4N coordination sphere) by dimerization, with the formula {[(tBuO)4Al]Cu(OH).py}2. The formation of all of these isolated products is not always straightforward because some of these compounds in solution are subject to decomposition or are involved in equilibria. Besides NMR [copper(I) compounds], UV absorptions and magnetic moments are used to characterize the compounds. PMID:18186626

Veith, Michael; Valtchev, Kroum; Huch, Volker

2008-02-01

332

Studies on copper alloys containing chromium on the copper side phase diagram  

NASA Technical Reports Server (NTRS)

Specimens were prepared from vacuum melted alloys of high purity vacuum melted copper and electrolytic chromium. The liquidus and eutectic point were determined by thermal analysis. The eutectic temperature is 1974.8 F and its composition is 1.28 wt% of chromium. The determination of solid solubility of chromium in copper was made by microscopic observation and electrical resistivity measurement. The solubility of chromium in solid copper is 0.6 wt% at 1050 F, 0.4 wt% at 1000 F, 0.25 wt% at 950 F, 0.17 wt% at 900 F, and 0.30 wt% at 840 F.

Doi, T.

1984-01-01

333

Mineral resource of the month: copper  

USGS Publications Warehouse

The article provides information on copper and its various uses. It was the first metal used by humans and is considered as one of the materials that played an important role in the development of civilization. It is a major industrial metal because of its low cost, availability, electrical conductivity, high ductility and thermal conductivity. Copper has long been used in the circuitry of electronics and the distribution of electricity and is now being used in silicon-based computer chips, solar and wind power generation, and coinage.

2011-01-01

334

6,000 years of copper smelting : Center for the Study of Copper Smelting in Ancient Societies  

E-print Network

In 1959 professor of archeology Beno Rothenberg began investigating the production of copper in the Sinai desert and Aravah region of southern Israel. He discovered over 650 previously unknown ancient copper mining and ...

Steinberg, Marc J. (Marc Jonathan), 1969-

2000-01-01

335

Copper oxide incorporated mesoporous alumina for defluoridation of drinking water  

Microsoft Academic Search

In the present study mesoporous alumina was modified by coating copper oxide to enhance the defluoridation of water. The copper oxide coated alumina (COCA) was synthesised by impregnating alumina with copper sulphate solution followed by calcination at 450°C in presence of air. The COCA was thoroughly characterised using powder XRD, SEM and BET surface area analysis. It was observed that

Amit Bansiwal; Pradnya Pillewan; Rajesh B. Biniwale; Sadhana S. Rayalu

2010-01-01

336

Dynamic Multibody Protein Interactions Suggest Versatile Pathways for Copper Trafficking  

E-print Network

Dynamic Multibody Protein Interactions Suggest Versatile Pathways for Copper Trafficking Aaron M, United States *S Supporting Information ABSTRACT: As part of intracellular copper trafficking pathways, the human copper chaperone Hah1 delivers Cu+ to the Wilson's Disease Protein (WDP) via weak and dynamic

Chen, Peng

337

Biosorption of Copper from Waste Waters: A Review  

Microsoft Academic Search

A comprehensive literature review has been carried out on the sorption of copper ions onto various biosorbents. Extensive research has been carried out using peat as a sorbent and the sorption capacity of copper on different peats varies by a factor of over fifty. Furthermore, this paper identifies that copper sorption capacities have been reported for over thirty other different

G. McKay; Y. S. Ho; J. C. Y. Ng

1999-01-01

338

Superplastic Extensibility of Nanocrystalline Copper at Room Temperature  

Microsoft Academic Search

A bulk nanocrystalline (nc) pure copper with high purity and high density was synthesized by electrodeposition. An extreme extensibility (elongation exceeds 5000%) without a strain hardening effect was observed when the nc copper specimen was rolled at room temperature. Microstructure analysis suggests that the superplastic extensibility of the nc copper originates from a deformation mechanism dominated by grain boundary activities

L. Lu; M. L. Sui; K. Lu

2000-01-01

339

Copper deficiency in a herd of captive muskoxen.  

PubMed Central

At necropsy, a mature muskox cow was found to have exceedingly low serum and liver copper concentrations of 4.8 = mumol/L and 0.02 mmol/kg, respectively. Serum copper levels were also low in remaining members of the herd but returned to normal after parenteral treatment with calcium copper edetate. PMID:9592616

Blakley, B R; Tedesco, S C; Flood, P F

1998-01-01

340

Die-cast copper rotors for improved motor performance  

Microsoft Academic Search

Aluminum has been the common conductor material for the squirrel cage of the induction motor largely because of ease of manufacturing by pressure die casting. Short die life in die casting the higher melting copper resulting in high production cost has prevented the copper rotor from attaining a place in integral horsepower motors. Because of its higher electrical conductivity, copper

John G. Cowie; D. T. Brender

2003-01-01

341

Copper effects on reproductive stages of Baltic Sea Fucus vesiculosus  

Microsoft Academic Search

Copper is an active ingredient in many antifouling products, and pleasure boats are estimated to be the major single source of copper pollution in Swedish coastal waters. For this reason, the effects of copper were studied on egg volume, fertilization, germination and development of apical hairs of Baltic Sea Fucus vesiculosus L. Germination was the most sensitive stage and was

S. Andersson; L. Kautsky

1996-01-01

342

Heat transfer enhancement of copper nanofluid with acoustic cavitation  

Microsoft Academic Search

Heat transfer characteristics of copper nanofluids with and without acoustic cavitation were investigated experimentally. The effects of such factors as acoustical parameters, nanofluid concentration and fluid subcooling on heat transfer enhancement around a heated horizontal copper tube were discussed in detail. The results indicated that the copper nanoparticles and acoustic cavitation had profound and significant influence on heat transport in

D. W. Zhou

2004-01-01

343

Alteration of the zinc and copper concentrationofhair1' 2  

Microsoft Academic Search

A washing and analytical procedure for the analysis of the zinc and copper concentrations of hair samples is described. The treatment of samples with a nonionic detergent + EDTA wash removed the most adsorbed zinc and copper from hair and was the washing procedure chosen for routine analyses. Beauty treatments had a variable effect on hair zinc and copper concentrations;

Joan M. McKenzie

344

Polyurethane nanofibers containing copper nanoparticles as future materials  

Microsoft Academic Search

In the present study, we aimed to represent a novel approach to fabricate polyurethane nanofibers containing copper nanoparticles (NPs) by simple electrospinning process. A simple method, not depending on additional foreign chemicals, has been employed to utilize prepared copper NPs in polyurethane nanofibers. Typically, a colloidal gel consisting of copper NPs and polyurethane has been electrospun. SEM-EDX and TEM results

Faheem A. Sheikh; Muzafar A. Kanjwal; Saurabh Saran; Wook-Jin Chung; Hern Kim

2011-01-01

345

Copper load in Mute Swans (Cygnus olor) found in Denmark.  

PubMed

Organs from 91 Mule Swans were analyzed for copper and lead. Swans from an area known to be polluted with copper had an average copper content in their livers of nearly 1100 mg/kg or more than twice as much as swams from other parts of Denmark. PMID:683855

Clausen, B; Wolstrup, C

1978-06-01

346

Moisture induced corrosion in gold and copper ball bonds  

Microsoft Academic Search

High gold prices have led to renewed interest in replacing gold with copper in existing packages and new packages in order to save costs. Although reliability is often cited as a reason for using copper, the main driving force for its use is undoubtedly cost. Perceptions that copper wire is more reliable are based on the notion that the intermetallics

C. D. Breach; Wai Mun Tee; Teck Kheng Lee; R. Holliday

2010-01-01

347

Mechanism of copper patina formation in marine environments  

Microsoft Academic Search

Data analysis of the initial superficial layers of copper patina formed in several marine environments, using X-ray diffraction and cathodic reduction techniques, are presented. It was observed that cuprite phase decreases and the paratacamite phase increases, as corrosion develops on the surface of copper. The data presented show good agreement with previously published eletrochemical reactions of copper corrosion in marine

L. Veleva; P. Quintana; R. Ramanauskas; R. Pomes; L. Maldonado

1996-01-01

348

Metallic copper corrosion rates, moisture content, and growth medium influence survival of copper ion-resistant bacteria  

Microsoft Academic Search

The rapid killing of various bacteria in contact with metallic copper is thought to be influenced by the influx of copper\\u000a ions into the cells, but the exact mechanism is not fully understood. This study showed that the kinetics of contact killing\\u000a of copper surfaces depended greatly on the amount of moisture present, copper content of alloys, type of medium

Jutta Elguindi; Stuart Moffitt; Henrik Hasman; Cassandra Andrade; Srini Raghavan; Christopher Rensing

2011-01-01

349

Electrolytic recovery of copper and regeneration of nitric acid from a copper strip solution  

SciTech Connect

The fabrication of nuclear fuels involves stripping of a copper jacket with nitric acid. The waste acid, which contains 3.0 to 4.5 N nitric acid and 100 to 180 g/L copper, is currently discharged, neutralized, and disposed of in solar evaporation ponds. Alternative waste disposal and treatment methods including electrowinning are being investigated. Laboratory-scale electrowinning tests have been conducted in an air-sparged cell at current densities from 0.027 to 0.22 A/cm/sup 2/. The efficiency of copper recovery was improved by adding sulfamic acid or by cooling the electrolyte. Copper current efficiency ranged from 55% to 95%; energy consumption ranged from 1.8 to 6.6 kWh/kg Cu. Results of the laboratory-scale electrowinning tests are summarized. A brief economic comparison of an alternative waste disposal and acid recycle technique is presented.

Stewart, T.L.; Hartley, J.N.

1985-01-01

350

"Pulling the plug" on cellular copper: The role of mitochondria in copper export Scot C. Leary a,  

E-print Network

Keywords: Mitochondria Superoxide dismutase Cytochrome c oxidase SCO proteins Copper trafficking 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

Leary, Scot

351

Cyanobacterial metallochaperone inhibits deleterious side reactions of copper.  

PubMed

Copper metallochaperones supply copper to cupro-proteins through copper-mediated protein-protein-interactions and it has been hypothesized that metallochaperones thereby inhibit copper from causing damage en route. Evidence is presented in support of this latter role for cyanobacterial metallochaperone, Atx1. In cyanobacteria Atx1 contributes towards the supply of copper to plastocyanin inside thylakoids but it is shown here that in copper-replete medium, copper can reach plastocyanin without Atx1. Unlike metallochaperone-independent copper-supply to superoxide dismutase in eukaryotes, glutathione is not essential for Atx1-independent supply to plastocyanin: Double mutants missing atx1 and gshB (encoding glutathione synthetase) accumulate the same number of atoms of copper per cell in the plastocyanin pool as wild type. Critically, ?atx1?gshB are hypersensitive to elevated copper relative to wild type cells and also relative to ?gshB single mutants with evidence that hypersensitivity arises due to the mislocation of copper to sites for other metals including iron and zinc. The zinc site on the amino-terminal domain (ZiaA(N)) of the P(1)-type zinc-transporting ATPase is especially similar to the copper site of the Atx1 target PacS(N), and ZiaA(N) will bind Cu(I) more tightly than zinc. An NMR model of a substituted-ZiaA(N)-Cu(I)-Atx1 heterodimer has been generated making it possible to visualize a juxtaposition of residues surrounding the ZiaA(N) zinc site, including Asp(18), which normally repulse Atx1. Equivalent repulsion between bacterial copper metallochaperones and the amino-terminal regions of P(1)-type ATPases for metals other than Cu(I) is conserved, again consistent with a role for copper metallochaperones to withhold copper from binding sites for other metals. PMID:22198771

Tottey, Steve; Patterson, Carl J; Banci, Lucia; Bertini, Ivano; Felli, Isabella C; Pavelkova, Anna; Dainty, Samantha J; Pernil, Rafael; Waldron, Kevin J; Foster, Andrew W; Robinson, Nigel J

2012-01-01

352

Cyanobacterial metallochaperone inhibits deleterious side reactions of copper  

PubMed Central

Copper metallochaperones supply copper to cupro-proteins through copper-mediated protein-protein-interactions and it has been hypothesized that metallochaperones thereby inhibit copper from causing damage en route. Evidence is presented in support of this latter role for cyanobacterial metallochaperone, Atx1. In cyanobacteria Atx1 contributes towards the supply of copper to plastocyanin inside thylakoids but it is shown here that in copper-replete medium, copper can reach plastocyanin without Atx1. Unlike metallochaperone-independent copper-supply to superoxide dismutase in eukaryotes, glutathione is not essential for Atx1-independent supply to plastocyanin: Double mutants missing atx1 and gshB (encoding glutathione synthetase) accumulate the same number of atoms of copper per cell in the plastocyanin pool as wild type. Critically, ?atx1?gshB are hypersensitive to elevated copper relative to wild type cells and also relative to ?gshB single mutants with evidence that hypersensitivity arises due to the mislocation of copper to sites for other metals including iron and zinc. The zinc site on the amino-terminal domain (ZiaAN) of the P1-type zinc-transporting ATPase is especially similar to the copper site of the Atx1 target PacSN, and ZiaAN will bind Cu(I) more tightly than zinc. An NMR model of a substituted-ZiaAN-Cu(I)-Atx1 heterodimer has been generated making it possible to visualize a juxtaposition of residues surrounding the ZiaAN zinc site, including Asp18, which normally repulse Atx1. Equivalent repulsion between bacterial copper metallochaperones and the amino-terminal regions of P1-type ATPases for metals other than Cu(I) is conserved, again consistent with a role for copper metallochaperones to withhold copper from binding sites for other metals. PMID:22198771

Tottey, Steve; Patterson, Carl J.; Banci, Lucia; Bertini, Ivano; Felli, Isabella C.; Pavelkova, Anna; Dainty, Samantha J.; Pernil, Rafael; Waldron, Kevin J.; Foster, Andrew W.; Robinson, Nigel J.

2012-01-01

353

Copper speciation survey from UK marinas, harbours and estuaries.  

PubMed

The use of copper in antifouling paints has increased in the UK in the last 20 years as TBT and several other organic biocides have been phased out. To assess the probable impact of copper on estuarine systems a survey was undertaken to measure the different fractions of copper present in the water column at current usage. The different fractions measured were; labile copper, (LCu) considered as both the free copper ions and inorganically bound copper, the total dissolved copper (TDCu) present, and the difference between them taken as the organically bound likely non-toxic copper fraction. The survey considered sites with different levels of boat use, namely marinas, harbours and estuaries, differing physical parameters of suspended and dissolved organic matter, different seasons of the year and different depths in the water column all of which control speciation behaviour. Suspended particulate matter (SPM) values were measured at all sites and increased from West to East coast locations (5.7-34.4 mg/l). Dissolved organic matter (DOM) values ranged from 0.58 to 2.2mg/l C. The total dissolved copper concentrations ranged from 0.30 to 6.68 microg/l, with labile fraction ranging from 0.02 to 2.69 microg/l, and most labile copper concentrations below 1 microg/l. None of the yearly mean copper measurements exceeded the 76/464/EEC EQS of 5 microg/l. Of the 306 measurements, only one dissolved copper value in one season was above 5 microg/l. This ratio of labile to total copper was between 10 and 30%. The results from this survey suggest that if toxicity of copper is due to the labile fraction then using the total dissolved copper concentrations as an indicator of impact overestimate the risk by a factor of four times. PMID:17599362

Jones, Bryn; Bolam, Thi

2007-08-01

354

Searching for specific responses to copper exposure: an in vitro copper challenge in peripheral mononuclear cells.  

PubMed

Acute and chronic cellular responses to changes in copper availability are not clear when these changes are mild to moderate, as what often occur in human daily life. The aims of the study were to develop an in vitro copper challenge in peripheral mononuclear cells (PMNCs) obtained from healthy individuals with different preconditioning copper treatments, and measure copper and iron content, and MT2A and TfR mRNA abundance after the copper challenge. (1) Screening using clinical and biochemical indicators defined healthy participants, who received 8 mg Cu/day (copper sulfate) or placebo for 2 months. (2) Mononuclear cells were obtained on days 0, 2 (acute changes), and 60 (chronic changes). (3) Cells were challenged with a 1, 5, and 20 ?M Cu-histidine for 20 h, at T0, T2, and T60. Cells from both supplemented and placebo individuals showed a clear trend to increase copper content when there was more copper in the media. Increases were greater in the supplemented group, larger with 20 ?M Cu (p?copper concentration, but TfR transcripts did not change. An in vitro challenge of PMNC showed specific changes of cellular copper and MT2A, while changes of iron content and TfR mRNA abundance were not consistent. PMNCs appear as good candidates to assess changes of cellular copper availability. That results differed after acute (T2) and chronic (T60) supplementation suggests that acute and chronic changes are handled differently by these cells. PMID:20737243

Arredondo, Miguel; Espinoza, Alejandra; Pizarro, Fernando; Araya, Magdalena

2011-09-01

355

Preparation of a Novel Copper Catalyst in Terms of the Immiscible Interaction Between Copper and Chromium  

Microsoft Academic Search

Based on the metallurgical point of view, we aimed to design a new form of copper catalysts with high thermal stability and\\u000a activity. Delafossite CuCrO2 has been studied as a precursor for copper catalyst. The CuCrO2 was reduced to fine dispersion of Cu and Cr2O3 particles with porous structure by the treatment in H2 at 600 °C, which exhibited much higher

Satoshi Kameoka; Mika Okada; An Pang Tsai

2008-01-01

356

Copper speciation and toxicity in Macquarie Harbour, Tasmania: an investigation using a copper ion selective electrode  

Microsoft Academic Search

Growth inhibition bioassays using Nitzschia closterium were used to determine the relationship between the reduction in the growth rate and the concentration of free copper ion (Cufree) as measured with a copper Ion-Selective Electrode (ISE). At a salinity of 20, no toxicity was found for Cufree=10?11.79 M while, for Cufree=10?8.20 M, the growth rate was reduced to <8% of the

Ruth S Eriksen; Denis J Mackey; Rick van Dam; Barbara Nowak

2001-01-01

357

Mutant SOD1 causes motor neuron disease independent of copper chaperone–mediated copper loading  

Microsoft Academic Search

Copper-mediated oxidative damage is proposed to play a critical role in the pathogenesis of Cu\\/Zn superoxide dismutase (SOD1)–linked familial amyotrophic lateral sclerosis (FALS). We tested this hypothesis by ablating the gene encoding the copper chaperone for SOD1 (CCS) in a series of FALS-linked SOD1 mutant mice. Metabolic 64Cu labeling in SOD1-mutant mice lacking the CCS showed that the incorporation of

Jamuna R. Subramaniam; W. Ernest Lyons; Jian Liu; Thomas B. Bartnikas; Jeffrey Rothstein; Donald L. Price; Don W. Cleveland; Jonathan D. Gitlin; Philip C. Wong

2002-01-01

358

Overheating of flexible tinned copper connectors  

Microsoft Academic Search

Overheating of flexible tinned copper connectors has been observed at a number of power stations. These connectors are used to connect the generator to outgoing busbars and transformers thus serving to counter the effects of vibration and thermal expansion forces. It is shown that the main cause for the observed overheating is a result of a combined action of the

Milenko Braunovic

2001-01-01

359

ENVIRONMENTAL CONSIDERATION FOR EMERGING COPPER WINNING PROCESSES  

EPA Science Inventory

Fourteen processes for the production of copper were examined to evaluate their potential environmental impact, economics and energy requirements relative to reverberatory smelting as commonly practices in the U.S. Because of limitations in data available for more recent process ...

360

Advanced copper interconnections for silicon CMOS technologies  

Microsoft Academic Search

Interconnects for advanced semiconductor devices are facing increasingly difficult challenges. Several material alternatives are being investigated in order to meet very strict requirements. Currently, copper is the most widely accepted material for advanced metallization. This article gives a general overview of the world-wide R&D effort underway to develop both manufacturable processes and their integration at each level of the interconnect

J. Torres

1995-01-01

361

Alternative Anode Reaction for Copper Electrowinning  

SciTech Connect

This report describes a project funded by the Department of Energy, with additional funding from Bechtel National, to develop a copper electrowinning process with lower costs and lower emissions than the current process. This new process also includes more energy efficient production by using catalytic-surfaced anodes and a different electrochemical couple in the electrolyte, providing an alternative oxidation reaction that requires up to 50% less energy than is currently required to electrowin the same quantity of copper. This alternative anode reaction, which oxidizes ferric ions to ferrous, with subsequent reduction back to ferric using sulfur dioxide, was demonstrated to be technically and operationally feasible. However, pure sulfur dioxide was determined to be prohibitively expensive and use of a sulfur burner, producing 12% SO{sub 2}, was deemed a viable alternative. This alternate, sulfur-burning process requires a sulfur burner, waste heat boiler, quench tower, and reaction towers. The electrolyte containing absorbed SO{sub 2} passes through activated carbon to regenerate the ferrous ion. Because this reaction produces sulfuric acid, excess acid removal by ion exchange is necessary and produces a low concentration acid suitable for leaching oxide copper minerals. If sulfide minerals are to be leached or the acid unneeded on site, hydrogen was demonstrated to be a potential reductant. Preliminary economics indicate that the process would only be viable if significant credits could be realized for electrical power produced by the sulfur burner and for acid if used for leaching of oxidized copper minerals on site.

Not Available

2005-07-01

362

A Simulator for Copper Ore Leaching  

SciTech Connect

This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). Copper is a strategic metal and the nation needs a secure supply both for industrial use and military needs. However, demand is growing worldwide and is outstripping the ability of the mining industry to keep up. Improved recovery methods are critically needed to maintain the balance of supply and demand. The goal of any process design should be to increase the amount of copper recovered, control movement of acid and other environmentally harmful chemicals, and reduce energy requirements. To achieve these ends, several improvements in current technology are required, the most important of which is a better understanding of, and the ability to quantify, how fluids move through heterogeneous materials in a complex chemical environment. The goal of this project is create a new modeling capability that couples hydrology with copper leaching chemistry . once the model has been verified and validated, we can apply the model to specific problems associated with heap leaching (flow channeling due to non-uniformities in heap structure, precipitation/dissolution reactions, and bacterial action), to understand the causes of inefficiencies, and to design better recovery systems. We also intend to work with representatives of the copper mining industry to write a coordinated plan for further model development and application that will provide economic benefits to the industry and the nation.

Travis, B.

1999-05-14

363

Microvascular effects of copper deficiency in rats  

SciTech Connect

We have studied the microcirculatory responses in copper deficient rats using the rat cremaster muscle preparation. Male Sprague-Dawley rats were fed either a copper supplemented diet (CuS, 5 ppm) or a copper deficient diet (CuD, O ppm) for five weeks prior to experimentation. The rats (240-300g) were anesthetized with pentobarbital and the cremaster (with intact nerve and blood supply) were spread in a tissue bath filled with krebs solution. In vivo television microscopy was used to observe the microcirculation. Fluorescein isothiocyanate tagged to bovine serum albumin (FITC-BSA) was injected i.a. 30 min prior to the start of experimentation. In the CuS animals photoactivation of the intravascular FITC-BSA caused significant platelet aggregation and reduction in red blood cell column diameter (RBCCD) by 30 min and stasis of flow by 60 min. In CuD animals there was no reduction in RBCCD and only minor platelet aggregation after 60 min of photoactivation. Topical administration of compound 48/80 (1.0 and 10.0 {mu}g/ml) induced a significantly greater macromolecular leakage (increased interstitial fluorescence of FITC-BSA) in the CuD animals than in the control, CuS animals. These results suggest that copper deficiency results in marked alterations of the regulatory mechanisms governing thrombosis and inflammation.

Schuschke, D.A.; Saari, J.T.; Ackermann, D.M.; Miller, F.N. (Univ. of Louisville, KY (USA))

1989-02-15

364

Portal copper transport in rats by albumin  

SciTech Connect

The distribution of newly absorbed copper among serum proteins obtained from the portal circulation of rats was examined by conventional and high-performance gel filtration chromatography, affinity chromatography, and Western blotting. Within 10-30 min after being administered by gavage or directly into the intestine, /sup 67/Cu and /sup 64/Cu, respectively, were recovered in the albumin fraction. By 8 h after administration of the radionuclides, virtually all of the radioactivity was found with ceruloplasmin. Affigel blue fractionation and subsequent Superose-6 chromatography further demonstrated that all of the copper in the albumin-containing fractions was in fact bound to this protein rather than high molecular weight moieties. Vascular perfusion of the isolated rat intestine, where /sup 64/Cu was infused into the lumen, showed that newly absorbed /sup 64/Cu in the vascular perfusate collected from the cannulated portal vein was associated with albumin. Uptake of radioactivity by isolated rat liver parenchymal cells from medium containing rat serum with /sup 67/Cu bound to albumin was demonstrated. In vitro binding of /sup 64/Cu to serum proteins that were transferred to nitrocellulose by Western blotting techniques showed that albumin is essentially the only protein that binds appreciable amounts of copper. The data suggest that albumin is the plasma protein that is responsible for the initial transport of copper after absorption.

Gordon, D.T.; Leinart, A.S.; Cousins, R.J.

1987-03-01

365

Method for copper staining of germanium crystals  

NASA Technical Reports Server (NTRS)

Proper conditions for copper staining of germanium crystals include a low solution temperature of 3 degrees C, illumination of the sample by infrared light, and careful positioning of the light source relative to the sample so as to minimize absorption of the infrared light.

Rivet, E. J.

1969-01-01

366

The SNOOPY Contradistinctive Copper Experiment: Calibration Results  

NASA Technical Reports Server (NTRS)

The Contradistinctive Copper nanoexperiment was designed to investigate the highly oxidizing and abrasive conditions expected on the surface of Mars. The experiment was conceived in response to the MECA Student Nanoexperiment Challenge in 1999. Additional information is contained in the original extended abstract.

Sherman, J.; Trowbridge, K.; Waldron, A. M.; Batt, C. A.; Kuhlman, K. R.

2002-01-01

367

Reliable laser micro-welding of copper  

NASA Astrophysics Data System (ADS)

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 Nd:YAG laser) is much better absorbed by copper at room temperature. Combining the two wavelengths and using the drastic increase in absorption with increasing temperature leads to an efficient spot welding solution. By the use of intelligent pulse forming with the thermal pulses of a Nd:YAG laser the spot weld reliability is improved significantly. This paper discusses a solution where Nd:YAG laser pulses composed of 85 - 90% of 1 micron and 10 - 15% of 532 nm radiation are used for spot welding of 80 - 300 micron thick copper ribbons. A weld spot diameter variation below 6% combined with 100% full penetration welding is achieved. The process efficiency is improved by more than a factor of two compared to conventional spot welding with 1 micron radiation.

Rüttimann, Christoph; Dürr, Ulrich; Moalem, Anas; Priehs, Marc

2011-03-01

368

21 CFR 73.1647 - Copper powder.  

...million. Lead (as Pb), not more than 20 parts per million. Arsenic (as As), not more than 3 parts per million. Mercury (as Hg), not more than 1 part per million. Copper (as Cu), not less than 95 percent. Maximum particle size...

2014-04-01

369

Copper, oxidative stress, and human health  

Microsoft Academic Search

Copper (Cu), a redox active metal, is an essential nutrient for all species studied to date. During the past decade, there has been increasing interest in the concept that marginal deficits of this element can contribute to the development and progression of a number of disease states including cardiovascular disease and diabetes. Deficits of this nutrient during pregnancy can result

Janet Y. Uriu-Adams; Carl L. Keen

2005-01-01

370

Metalcasting: Die Casting Copper Motor Rotors  

SciTech Connect

Decreased energy requirements, air emissions, production time, and operating costs are some of the benefits that will accrue to the metalcasting industry as result of this new die casting technique. This fact sheet provides the details of this exciting new process for fabricating copper motor rotors.

Recca, L.

1999-01-29

371

Stress Corrosion cracking of copper single crystals  

Microsoft Academic Search

Constant extension rate tests have been carried out on copper single crystals in a sodium nitrite solution, using an applied potential to accelerate the cracking. Crack velocities up to 30 nm per second were obtained at 30 °C. The stress-corrosion fracture surfaces are cleavage-like, with curved striations parallel to the crack front. If the dynamic straining is stopped, the cracks

K. Sieradzki; R. L. Sabatini; R. C. Newman

1984-01-01

372

Corrosion characteristics of copper-based IUDs  

Microsoft Academic Search

A corrosion study of the intra-uterine device, “TCu 380 A”, was made using cyclic voltammetry (CV), scanning electron microscopy (SEM) and optical microscopy (OM). Blood plasma, whole blood and artificial uterine fluid were used as corrosive media in order to establish a comparative scheme of the corrosion behaviour of copper in the device. In summary, the results obtained were not

S. Benjamín Valdez; G. Navor Rosas; B. Mónica Carrillo; L. Tezozomoc Pérez; Tetsuya Ogura; G. Celia Beltrán; J. Miguel

2003-01-01

373

Anodization of Copper in Chloride Media.  

National Technical Information Service (NTIS)

The main objective of this phase was to lay the theoretical and experimental groundwork for the determination of standard potentials and complex ion formation constants for metal-metal ion-ligand systems. The metal of interest is copper and the ligands in...

J. G. Osteryoung

1994-01-01

374

Copper Planar Microcoils Applied to Magnetic Actuation  

Microsoft Academic Search

Recent advances in microtechnology allow realization of planar microcoils. These components are integrated in MEMS as magnetic sensor or actuator. In the latter case, it is necessary to maximize the effective magnetic field which is proportional to the current passing through the copper track and depends on the distance to the generation microcoil. The aim of this work was to

Johan Moulin; Marion Woytasik; Emile Martincic; Elisabeth Dufour-gergam

2008-01-01

375

A copper alloy development for leadframe  

Microsoft Academic Search

Technical requirements for leadframe material with the trends in packaging technology such as shrink in size and increasing heat dissipation are first summarized. A new precipitation hardening leadframe copper alloy which meets technical requirements is then introduced in terms of advantages related with package reliability

Yasuo Tomioka; Junji Miyake

1995-01-01

376

Metal Nitride Diffusion Barriers for Copper Interconnects  

E-print Network

, and HRTEM. The electrical resistivity measured by FPP was as low as 70 mu omega-cm. Preliminary copper diffusion tests showed good diffusion barrier properties with a diffusion depth of 2~3 nm after vacuum annealing at 500 degrees C for 30 minutes...

Araujo, Roy A.

2010-01-14

377

Copper hazards to fish, wildlife and invertebrates: a synoptic review  

USGS Publications Warehouse

Selective review and synthesis of the technical literature on copper and copper salts in the environment and their effects primarily on fishes, birds, mammals, terrestrial and aquatic invertebrates, and other natural resources. The subtopics include copper sources and uses; chemical and biochemical properties; concentrations of copper in field collections of abiotic materials and living organisms; effects of copper deficiency; lethal and sublethal effects on terrestrial plants and invertebrates, aquatic organisms, birds and mammals, including effects on survival, growth, reproduction, behavior, metabolism, carcinogenicity, matagenicity, and teratogenicity; proposed criteria for the protection of human health and sensitive natural resources; and recommendations for additional research.

Eisler, Ronald

1998-01-01

378

Synthesis of carbon nanotubes and nanotube forests on copper catalyst  

NASA Astrophysics Data System (ADS)

The growth of carbon nanotubes on bulk copper is studied. We show for the first time, that super growth chemical vapor deposition method can be successfully applied for preparation of nanotubes on copper catalyst, and the presence of hydrogen is necessary. Next, different methods of copper surface activation are studied, to improve catalyst efficiency. Among them, applied for the first time for copper catalyst in nanotubes synthesis, sulfuric acid activation is the most promising. Among tested samples the surface modified for 10 min is the most active, causing the growth of vertically aligned carbon nanotube forests. Obtained results have potential importance in application of nanotubes and copper in electronic chips and nanodevices.

Kruszka, Bartosz; Terzyk, Artur P.; Wi?niewski, Marek; Gauden, Piotr A.; Szybowicz, Miros?aw

2014-09-01

379

A New Manufacturing Technology for Induction Machine Copper Rotors  

SciTech Connect

The benefits of energy and operational cost savings from using copper rotors are well recognized. The main barrier to die casting copper rotors is short mold life. This paper introduces a new approach for manufacturing copper-bar rotors. Either copper, aluminum, or their alloys can be used for the end rings. Both solid-core and laminated-core rotors were built. High quality joints of aluminum to copper were produced and evaluated. This technology can also be used for manufacturing aluminum bar rotors with aluminum end rings. Further development is needed to study the life time reliability of the joint, to optimize manufacturing fixtures, and to conduct large-rotor tests.

Hsu, J.S.

2001-09-04

380

Nanoparticle plasma ejected directly from solid copper by localized microwaves  

SciTech Connect

A plasma column ejected directly from solid copper by localized microwaves is studied. The effect stems from an induced hotspot that melts and emits ionized copper vapors as a confined fire column. Nanoparticles of {approx}20-120 nm size were revealed in the ejected column by in situ small-angle x-ray scattering. Optical spectroscopy confirmed the dominance of copper particles in the plasma column originating directly from the copper substrate. Nano- and macroparticles of copper were verified also by ex situ scanning electron microscopy. The direct conversion of solid metals to nanoparticles is demonstrated and various applications are proposed.

Jerby, E.; Golts, A.; Shamir, Y.; Wonde, S.; Ashkenazi, D.; Eliaz, N. [Faculty of Engineering, Tel Aviv University, Ramat Aviv 69978 (Israel); Mitchell, J. B. A.; LeGarrec, J. L. [IPR., U.M.R. No. 6251 du C.N.R.S., Universite de Rennes I, 35042 Rennes (France); Narayanan, T.; Sztucki, M. [European Synchrotron Radiation Facility, BP-220, 38043 Grenoble (France); Barkay, Z. [Wolfson Applied Materials Research Center, Tel Aviv University, Ramat-Aviv 69978 (Israel)

2009-11-09

381

Superconducting properties of evaporated copper molybdenum sulfide films  

NASA Technical Reports Server (NTRS)

Films of copper molybdenum sulfide were produced by coevaporation. Those that were superconducting contained only the ternary compound and free molybdenum. The range of copper content in the ternary compound was as large as that in polycrystalline material, that is, it includes either phase alone, or a mixture of the two phases of this material. This is in contrast with sputtered materials where copper concentration has been limited to a narrower range. The upper critical field and the critical current were measured as functions of external magnetic field, and found to be similar to those of sputtered copper molybdenum sulfide, when the comparison was made for samples having the same amount of copper.

Woollam, J. A.; Chi, K. C.; Dillon, R. O.; Bunshah, R. F.; Alterovitz, S. A.

1978-01-01

382

Survival and Growth in the Presence of Elevated Copper: Transcriptional Profiling of Copper-Stressed Pseudomonas aeruginosa†  

PubMed Central

Transcriptional profiles of Pseudomonas aeruginosa exposed to two separate copper stress conditions were determined. Actively growing bacteria subjected to a pulse of elevated copper for a short period of time was defined as a “copper-shocked” culture. Conversely, copper-adapted populations were defined as cells actively growing in the presence of elevated copper. Expression of 405 genes changed in the copper-shocked culture, compared to 331 genes for the copper-adapted cultures. Not surprisingly, there were genes identified in common to both conditions. For example, both stress conditions resulted in up-regulation of genes encoding several active transport functions. However, there were some interesting differences between the two types of stress. Only copper-adapted cells significantly altered expression of passive transport functions, down-regulating expression of several porins belonging to the OprD family. Copper shock produced expression profiles suggestive of an oxidative stress response, probably due to the participation of copper in Fenton-like chemistry. Copper-adapted populations did not show such a response. Transcriptional profiles also indicated that iron acquisition is fine-tuned in the presence of copper. Several genes induced under iron-limiting conditions, such as the siderophore pyoverdine, were up-regulated in copper-adapted populations. Interesting exceptions were the genes involved in the production of the siderophore pyochelin, which were down-regulated. Analysis of the copper sensitivity of select mutant strains confirmed the array data. These studies suggest that two resistance nodulation division efflux systems, a P-type ATPase, and a two-component regulator were particularly important for copper tolerance in P. aeruginosa. PMID:17015663

Teitzel, Gail M.; Geddie, Ashley; De Long, Susan K.; Kirisits, Mary Jo; Whiteley, Marvin; Parsek, Matthew R.

2006-01-01

383

The role of copper in HL-60 cell differentiation  

SciTech Connect

Copper deficiency in humans has been shown to result in neutropenia. This research asks what is copper's function in the development of neutrophils HL-60 cells, a promyelocyte cell line, was induced to differentiate towards the granulocytic lineage with 1 {mu}M retinoic acid for 5 days. Both noninduced and induced cells were incubated in either complete medium or in medium supplemented with 8 {mu}M copper. Intracellular copper levels, Cu/Zn superoxide dismutase activity and the respiratory burst (RB) activity of the cells were measured. The respiratory burst of neutrophils is a measure of cellular function and degree of differentiation. Induced cells, as expected, showed greater RB activity than the non-induced cells. Copper supplementation, however, had no effect on this activity. Differentiated HL-60 cells had two times more intracellular copper but ten times less Cu/Zn-SOD activity. Copper supplementation enhanced Cu/Zn-SOD activity in both noninduced and induced cells. This suggests that the availability of intracellular copper is important in expressing Cu/ZN-SOD activity and that differentiated cells, although they have more intracellular copper under basal conditions, cannot utilize that copper for Cu/Zn-SOD enzyme activity. When supplemental copper was provided during differentiation, Cu/Zn-SOD activity was maintained.

Bae, B.; Percival, S.S. (Univ. of Florida, Gainesville (United States))

1991-03-15

384

Modeling MIC copper release from drinking water pipes.  

PubMed

Copper is used for household drinking water distribution systems given its physical and chemical properties that make it resistant to corrosion. However, there is evidence that, under certain conditions, it can corrode and release unsafe concentrations of copper to the water. Research on drinking water copper pipes has developed conceptual models that include several physical-chemical mechanisms. Nevertheless, there is still a necessity for the development of mathematical models of this phenomenon, which consider the interaction among physical-chemical processes at different spatial scales. We developed a conceptual and a mathematical model that reproduces the main processes in copper release from copper pipes subject to stagnation and flow cycles, and corrosion is associated with biofilm growth on the surface of the pipes. We discuss the influence of the reactive surface and the copper release curves observed. The modeling and experimental observations indicated that after 10h stagnation, the main concentration of copper is located close to the surface of the pipe. This copper is associated with the reactive surface, which acts as a reservoir of labile copper. Thus, for pipes with the presence of biofilm the complexation of copper with the biomass and the hydrodynamics are the main mechanisms for copper release. PMID:24398414

Pizarro, Gonzalo E; Vargas, Ignacio T; Pastén, Pablo A; Calle, Gustavo R

2014-06-01

385

Case of sensory ataxic ganglionopathy-myelopathy in copper deficiency.  

PubMed

Spinal cord involvement associated with severe copper deficiency has been reported in the last 8 years. Copper deficiency may produce an ataxic myelopathy. Clinical and neuroimaging findings are similar to the subacute combined degeneration seen in patients with vitamin B12 deficiency. Macrocytic, normocytic and microcytic anemia, leukopenia and, in severe cases, pancytopenia are well known hematologic manifestations. The most patients with copper deficiency myelopathy had unrecognized carency. Some authors suggested that early recognition and copper supplementation may prevent neurologic deterioration but clinical findings do not improve. We present a patient with copper deficiency, dorsal root ganglions and cervical dorsal columns involvement. Clinical status and neuroimaging improved after copper replacement therapy. Sensory neurons of dorsal root ganglia may be the most sensitive nervous pathway. In this case the early copper treatment allowed to improve neurologic lesions and to prevent further involvements. PMID:19022461

Zara, Gabriella; Grassivaro, Francesca; Brocadello, Filippo; Manara, Renzo; Pesenti, Francesco Francini

2009-02-15

386

Impurity control and removal in copper tankhouse operations  

NASA Astrophysics Data System (ADS)

During copper smelting, most of the undesirable impurities such as Pb, Sb, Bi, and As are only partially removed by oxidation. When white metal and blister copper are in equilibrium, these impurities are distributed mainly into the copper phase, from which their removal is difficult. When copper dissolves during electrorefining in a copper tankhouse, these impurities are continuously released from the anodes either as insoluble phases (slimes), which fall to the bottom of the cell, or as dissolved species in the electrolyte, the transfer of which to the cathode must be inhibited. This article presents impurity control methods in copper tankhouse operations with traditional and newly developed processes. It also summarizes the technologies demonstrated for removal of impurities from electrolyte that prevent them from being recycled in the copper smelting and refining circuit.

Wang, Shijie

2004-07-01

387

The delivery of copper for thylakoid import observed by NMR.  

PubMed

The thylakoid compartments of plant chloroplasts are a vital destination for copper. Copper is needed to form holo-plastocyanin, which must shuttle electrons between photosystems to convert light into biologically useful chemical energy. Copper can bind tightly to proteins, so it has been hypothesized that copper partitions onto ligand-exchange pathways to reach intracellular locations without inflicting damage en route. The copper metallochaperone Atx1 of chloroplast-related cyanobacteria (ScAtx1) engages in bacterial two-hybrid interactions with N-terminal domains of copper-transporting ATPases CtaA (cell import) and PacS (thylakoid import). Here we visualize copper delivery. The N-terminal domain PacS(N) has a ferredoxin-like fold that forms copper-dependent heterodimers with ScAtx1. Removal of copper, by the addition of the cuprous-ion chelator bathocuproine disulfonate, disrupts this heterodimer, as shown from a reduction of the overall tumbling rate of the protein mixture. The NMR spectral changes of the heterodimer versus the separate proteins reveal that loops 1, 3, and 5 (the carboxyl tail) of the ScAtx1 Cu(I) site switch to an apo-like configuration in the heterodimer. NMR data ((2)J(NH) couplings in the imidazole ring of (15)N ScAtx1 His-61) also show that His-61, bound to copper(I) in [Cu(I)ScAtx1](2), is not coordinated to copper in the heterodimer. A model for the PacS(N)/Cu(I)/ScAtx1 complex is presented. Contact with PacS(N) induces change to the ScAtx1 copper-coordination sphere that drives copper release for thylakoid import. These data also elaborate on the mechanism to keep copper(I) out of the ZiaA(N) ATPase zinc sites. PMID:16707580

Banci, Lucia; Bertini, Ivano; Ciofi-Baffoni, Simone; Kandias, Nikolaos G; Robinson, Nigel J; Spyroulias, Georgios A; Su, Xun-Cheng; Tottey, Stephen; Vanarotti, Murugendra

2006-05-30

388

Copper toxicity in a New Zealand dairy herd  

PubMed Central

Chronic copper toxicity was diagnosed in a Jersey herd in the Waikato region of New Zealand following an investigation into the deaths of six cattle from a herd of 250 dry cows. Clinical signs and post-mortem examination results were consistent with a hepatopathy, and high concentrations of copper in liver and blood samples of clinically affected animals confirmed copper toxicity. Liver copper concentrations and serum gamma-glutamyl transferase activities were both raised in a group of healthy animals sampled at random from the affected herd, indicating an ongoing risk to the remaining cattle; these animals all had serum copper concentrations within normal limits. Serum samples and liver biopsies were also collected and assayed for copper from animals within two other dairy herds on the same farm; combined results from all three herds showed poor correlation between serum and liver copper concentrations. To reduce liver copper concentrations the affected herd was drenched with 0.5 g ammonium molybdate and 1 g sodium sulphate per cow for five days, and the herd was given no supplementary feed or mineral supplements. Liver biopsies were repeated 44 days after the initial biopsies (approximately 1 month after the end of the drenching program); these showed a significant 37.3% decrease in liver copper concentrations (P <0.02). Also there were no further deaths after the start of the drenching program. Since there was no control group it is impossible to quantify the effect of the drenching program in this case, and dietary changes were also made that would have depleted liver copper stores. Historical analysis of the diet was difficult due to poor record keeping, but multiple sources of copper contributed to a long term copper over supplementation of the herd; the biggest source of copper was a mineral supplement. The farmer perceived this herd to have problems with copper deficiency prior to the diagnosis of copper toxicity, so this case demonstrates the importance of monitoring herd copper status regularly. Also the poor correlation between liver and serum copper concentrations in the three herds sampled demonstrates the importance of using liver copper concentration to assess herd copper status. PMID:25279139

2014-01-01

389

Measurement of the Young's modulus and internal friction of single crystal and polycrystalline copper, and copper-graphite composites as a function of temperature and orientation  

E-print Network

and internal friction (or mechanical damping) were made for three single crystal copper specimens, two types of polycrystalline copper, and copper-graphite composites with fibers oriented in the longitudinal or transverse direction. The PUCOT (piezoelectric... and internal friction (or mechanical damping) were made for three single crystal copper specimens, two types of polycrystalline copper, and copper-graphite composites with fibers oriented in the longitudinal or transverse direction. The PUCOT (piezoelectric...

Wickstrom, Steven Norman

2012-06-07

390

A Multinuclear Copper(I) Cluster Forms the Dimerization Interface in Copper-Loaded Human Copper Chaperone for Superoxide Dismutase  

SciTech Connect

Copper binding and X-ray aborption spectroscopy studies are reported on untagged human CCS (hCCS; CCS = copper chaperone for superoxide dismutase) isolated using an intein self-cleaving vector and on single and double Cys to Ala mutants of the hCCS MTCQSC and CSC motifs of domains 1 (D1) and 3 (D3), respectively. The results on the wild-type protein confirmed earlier findings on the CCS-MBP (maltose binding protein) constructs, namely, that Cu(I) coordinates to the CXC motif, forming a cluster at the interface of two D3 polypeptides. In contrast to the single Cys to Ser mutations of the CCS-MBP protein (Stasser, J. P., Eisses, J. F., Barry, A. N., Kaplan, J. H., and Blackburn, N. J. (2005) Biochemistry 44, 3143-3152), single Cys to Ala mutations in D3 were sufficient to eliminate cluster formation and significantly reduce CCS activity. Analysis of the intensity of the Cu-Cu cluster interaction in C244A, C246A, and C244/246A variants suggested that the nuclearity of the cluster was greater than 2 and was most consistent with a Cu4S6 adamantane-type species. The relationship among cluster formation, oligomerization, and metal loading was evaluated. The results support a model in which Cu(I) binding converts the apo dimer with a D2-D2 interface to a new dimer connected by cluster formation at two D3 CSC motifs. The predominance of dimer over tetramer in the cluster-containing species strongly suggests that the D2 dimer interface remains open and available for sequestering an SOD1 monomer. This work implicates the copper cluster in the reactive form and adds detail to the cluster nuclearity and how copper loading affects the oligomerization states and reactivity of CCS for its partner SOD1.

Stasser, J.P.; Siluvai, G.S.; Barry, A.N.; Blackburn, N.J.

2009-06-04

391

The Yeast Copper Response Is Regulated by DNA Damage  

PubMed Central

Copper is an essential but potentially toxic redox-active metal, so the levels and distribution of this metal are carefully regulated to ensure that it binds to the correct proteins. Previous studies of copper-dependent transcription in the yeast Saccharomyces cerevisiae have focused on the response of genes to changes in the exogenous levels of copper. We now report that yeast copper genes are regulated in response to the DNA-damaging agents methyl methanesulfonate (MMS) and hydroxyurea by a mechanism(s) that requires the copper-responsive transcription factors Mac1 and AceI, copper superoxide dismutase (Sod1) activity, and the Rad53 checkpoint kinase. Furthermore, in copper-starved yeast, the response of the Rad53 pathway to MMS is compromised due to a loss of Sod1 activity, consistent with the model that yeast imports copper to ensure Sod1 activity and Rad53 signaling. Crucially, the Mac1 transcription factor undergoes changes in its redox state in response to changing levels of copper or MMS. This study has therefore identified a novel regulatory relationship between cellular redox, copper homeostasis, and the DNA damage response in yeast. PMID:23959798

Dong, Kangzhen; Addinall, Stephen G.; Lydall, David

2013-01-01

392

Immobilization of copper flotation waste using red mud and clinoptilolite.  

PubMed

The flash smelting process has been used in the copper industry for a number of years and has replaced most of the reverberatory applications, known as conventional copper smelting processes. Copper smelters produce large amounts of copper slag or copper flotation waste and the dumping of these quantities of copper slag causes economic, environmental and space problems. The aim of this study was to perform a laboratory investigation to assess the feasibility of immobilizing the heavy metals contained in copper flotation waste. For this purpose, samples of copper flotation waste were immobilized with relatively small proportions of red mud and large proportions of clinoptilolite. The results of laboratory leaching demonstrate that addition of red mud and clinoptilolite to the copper flotation waste drastically reduced the heavy metal content in the effluent and the red mud performed better than clinoptilolite. This study also compared the leaching behaviour of metals in copper flotation waste by short-time extraction tests such as the toxicity characteristic leaching procedure (TCLP), deionized water (DI) and field leach test (FLT). The results of leach tests showed that the results of the FLT and DI methods were close and generally lower than those of the TCLP methods. PMID:18927060

Coruh, Semra

2008-10-01

393

The mechanism of copper uptake by tyrosinase from Bacillus megaterium.  

PubMed

Tyrosinase belongs to the type 3 copper enzyme family, containing a dinuclear copper center, CuA and CuB. It is mainly responsible for melanin production in a wide range of organisms. Although copper ions are essential for the activity of tyrosinase, the mechanism of copper uptake is still unclear. We have recently determined the crystal structure of tyrosinase from Bacillus megaterium (TyrBm) and revealed that this enzyme has tighter binding of CuA in comparison with CuB. Investigating copper accumulation in TyrBm, we found that the presence of copper has a more significant effect on the diphenolase activity. By decreasing the concentration of copper, we increased the diphenolase to monophenolase activity ratio twofold. Using a rational design approach, we identified five variants having an impact on copper uptake. We have found that a major role of the highly conserved Asn205 residue is to stabilize the orientation of the His204 imidazole ring in the binding site, thereby promoting the correct coordination of CuB. Further investigation of these variants revealed that Phe197, Met61, and Met184, which are located at the entrance to the binding site, not only play a role in copper uptake, but are also important for enhancing the diphenolase activity. We propose a mechanism of copper accumulation by the enzyme as well as an approach to changing the selectivity of TyrBm towards L-dopa production. PMID:24061559

Kanteev, Margarita; Goldfeder, Mor; Chojnacki, Micha?; Adir, Noam; Fishman, Ayelet

2013-12-01

394

Haemolymph protein composition and copper levels in decapod crustaceans  

NASA Astrophysics Data System (ADS)

Variations in haemolymph protein composition and concentration, in copper content and copper distribution in the tissue of decapod crustaceans are reviewed. Haemocyanin is the major haemolymph constituent (> 60%); the remaining proteins (in order of concentration) include coagulogen, apohaemocyanin, hormones and antisomes. Moulting, nutritional state, infection, hypoxia and salinity fluctuations are the major factors affecting the relative proportions and total quantities of the haemolymph proteins. With regard to haemocyanin, the changes in concentration during the moult cycle are principally associated with changes in haemolymph volume, rather than with changes in total haemocyanin content due to synthesis or catabolism. The role of the midgut gland in regulating haemolymph copper and haemocyanin concentration has been re-evaluated. More than 50% of the whole body copper load is stored in the haemolymph. In contrast, less than 3% of the copper load resides in the midgut gland. The latter has little potential for regulating haemolymph copper levels, at least in the short term (hours to a few days), though it may be involved in regulating haemocyanin levels over longer periods (weeks to months). The total copper content of the haemolymph remains within a narrow range, except during starvation when levels may decrease. Consequently, variations in the copper content of soft tissues, which constitute only 20% of decapod dry weight, do not significanlty alter whole body copper concentrations. Evidence that copper released following haemocyanin catabolism becomes bound to metallothionein for later use in the resynthesis of haemocyanin is reviewed and found to be inconclusive. The amount of copper that can be stored in this way is trivial compared with the amount of copper required to permit significant changes in haemolymph haemocyanin concentration. Average tissue copper requirements, calculated during the present study, are approx. 4 times higher than previous theoretical estimates.

Depledge, M. H.; Bjerregaard, P.

1989-06-01

395

Mechanisms of copper homeostasis in bacteria  

PubMed Central

Copper is an important micronutrient required as a redox co-factor in the catalytic centers of enzymes. However, free copper is a potential hazard because of its high chemical reactivity. Consequently, organisms exert a tight control on Cu+ transport (entry-exit) and traffic through different compartments, ensuring the homeostasis required for cuproprotein synthesis and prevention of toxic effects. Recent studies based on biochemical, bioinformatics, and metalloproteomics approaches, reveal a highly regulated system of transcriptional regulators, soluble chaperones, membrane transporters, and target cuproproteins distributed in the various bacterial compartments. As a result, new questions have emerged regarding the diversity and apparent redundancies of these components, their irregular presence in different organisms, functional interactions, and resulting system architectures. PMID:24205499

Argüello, José M.; Raimunda, Daniel; Padilla-Benavides, Teresita

2013-01-01

396

Precision micro drilling with copper vapor lasers  

SciTech Connect

The authors have developed a copper vapor laser based micro machining system using advanced beam quality control and precision wavefront tilting technologies. Micro drilling has been demonstrated through percussion drilling and trepanning using this system. With a 30 W copper vapor laser running at multi-kHz pulse repetition frequency, straight parallel holes with size varying from 500 microns to less than 25 microns and with aspect ratio up to 1:40 have been consistently drilled on a variety of metals with good quality. For precision trepanned holes, the hole-to-hole size variation is typically within 1% of its diameter. Hole entrance and exit are both well defined with dimension error less than a few microns. Materialography of sectioned holes shows little (sub-micron scale) recast layer and heat affected zone with surface roughness within 1--2 microns.

Chang, J.J.; Martinez, M.W.; Warner, B.E.; Dragon, E.P.; Huete, G.; Solarski, M.E.

1994-09-02

397

Exploring copper chelation in Alzheimer's disease protein  

NASA Astrophysics Data System (ADS)

Alzheimer's disease (AD) is a neurodegenerative disorder affecting millions of aging people in the U.S. alone. Clinical studies have indicated that metal chelation is a promising new approach in alleviating the symptoms of AD. Our study explores the as yet undetermined mechanism of copper chelation in amyloid-?, a protein implicated in AD. The structure of amyloid-? is derived from experimental results and incorporates a planar copper-ion-binding structure in a semi-solvated state. We investigate the chelation process using the nudged elastic band method implemented in our ab initio real-space multigrid code. We find that an optimal sequence of unbonding and rebonding events as well as proton transfers are required for a viable chelation process. These findings provide fundamental insight into the process of chelation that may lead to more effective AD therapies.

Rose, Frisco; Hodak, Miroslav; Bernholc, Jerry

2012-02-01

398

Reactively evaporated films of copper molybdenum sulfide  

NASA Technical Reports Server (NTRS)

Films of superconducting Chevrel-phase copper molybdenum sulfide CuxMo6S8 were deposited on sapphire substrates by reactive evaporation using H2S as the reacting gas. Two superconducting temperatures (10.0 K and 5.0 K) of the films were found, corresponding to two different phases with different copper concentrations. All films were superconducting above 4.2 K and contained Chevrel-phase compound as well as free molybdenum. The critical current was measured as a function of applied field. One sample was found to deviate from the scaling law found for co-evaporated or sputtered samples, which possibly indicates a different pinning mechanism or inhomogeneity of the sample.

Chi, K. C.; Dillon, R. O.; Bunshah, R. F.; Alterovitz, S.; Woollam, J. A.

1978-01-01

399

Copper Planar Microcoils Applied to Magnetic Actuation  

E-print Network

Recent advances in microtechnology allow realization of planar microcoils. These components are integrated in MEMS as magnetic sensor or actuator. In the latter case, it is necessary to maximize the effective magnetic field which is proportional to the current passing through the copper track and depends on the distance to the generation microcoil. The aim of this work was to determine the optimal microcoil design configuration for magnetic field generation. The results were applied to magnetic actuation, taking into account technological constraints. In particular, we have considered different realistic configurations that involve a magnetically actuated device coupled to a microcoil. Calculations by a semi-analytical method using Matlab software were validated by experimental measurements. The copper planar microcoils are fabricated by U.V. micromoulding on different substrates: flexible polymer (Kapton) and silicate on silicon. They are constituted by a spiral-like continuous track. Their total surface is ...

Moulin, J; Martincic, E; Dufour-Gergam, E

2008-01-01

400

Atomistic insights into aqueous corrosion of copper  

NASA Astrophysics Data System (ADS)

Corrosion is a fundamental problem in electrochemistry and represents a mode of failure of technologically important materials. Understanding the basic mechanism of aqueous corrosion of metals such as Cu in presence of halide ions is hence essential. Using molecular dynamics simulations incorporating reactive force-field (ReaxFF), the interaction of copper substrates and chlorine under aqueous conditions has been investigated. These simulations incorporate effects of proton transfer in the aqueous media and are suitable for modeling the bond formation and bond breakage phenomenon that is associated with complex aqueous corrosion phenomena. Systematic investigation of the corrosion process has been carried out by simulating different chlorine concentration and solution states. The structural and morphological differences associated with metal dissolution in the presence of chloride ions are evaluated using dynamical correlation functions. The simulated atomic trajectories are used to analyze the charged states, molecular structure and ion density distribution which are utilized to understand the atomic scale mechanism of corrosion of copper substrates under aqueous conditions. Increased concentration of chlorine and higher ambient temperature were found to expedite the corrosion of copper. In order to study the effect of solution states on the corrosion resistance of Cu, partial fractions of proton or hydroxide in water were configured, and higher corrosion rate at partial fraction hydroxide environment was observed. When the Cl- concentration is low, oxygen or hydroxide ion adsorption onto Cu surface has been confirmed in partial fraction hydroxide environment. Our study provides new atomic scale insights into the early stages of aqueous corrosion of metals such as copper.

Jeon, Byoungseon; Sankaranarayanan, Subramanian K. R. S.; van Duin, Adri C. T.; Ramanathan, Shriram

2011-06-01

401

Atomistic insights into aqueous corrosion of copper.  

PubMed

Corrosion is a fundamental problem in electrochemistry and represents a mode of failure of technologically important materials. Understanding the basic mechanism of aqueous corrosion of metals such as Cu in presence of halide ions is hence essential. Using molecular dynamics simulations incorporating reactive force-field (ReaxFF), the interaction of copper substrates and chlorine under aqueous conditions has been investigated. These simulations incorporate effects of proton transfer in the aqueous media and are suitable for modeling the bond formation and bond breakage phenomenon that is associated with complex aqueous corrosion phenomena. Systematic investigation of the corrosion process has been carried out by simulating different chlorine concentration and solution states. The structural and morphological differences associated with metal dissolution in the presence of chloride ions are evaluated using dynamical correlation functions. The simulated atomic trajectories are used to analyze the charged states, molecular structure and ion density distribution which are utilized to understand the atomic scale mechanism of corrosion of copper substrates under aqueous conditions. Increased concentration of chlorine and higher ambient temperature were found to expedite the corrosion of copper. In order to study the effect of solution states on the corrosion resistance of Cu, partial fractions of proton or hydroxide in water were configured, and higher corrosion rate at partial fraction hydroxide environment was observed. When the Cl(-) concentration is low, oxygen or hydroxide ion adsorption onto Cu surface has been confirmed in partial fraction hydroxide environment. Our study provides new atomic scale insights into the early stages of aqueous corrosion of metals such as copper. PMID:21702575

Jeon, Byoungseon; Sankaranarayanan, Subramanian K R S; van Duin, Adri C T; Ramanathan, Shriram

2011-06-21

402

Methane oxidation over catalytic copper oxides nanowires  

Microsoft Academic Search

Copper oxide (CuO) is one of the promising catalysts for the catalytic oxidation of methane (CH4). Previous studies have focused on CuO nanoparticles (NPs) dispersed on other supporting oxides. However, aggregation of CuO NPs under large loadings and solid state reactions between CuO and supports hinder the understanding and further improvement of the catalytic properties of CuO. Here, we report

Yunzhe Feng; Pratap M. Rao; Dong Rip Kim; Xiaolin Zheng

2011-01-01

403

Atomistic insights into aqueous corrosion of copper.  

SciTech Connect

Corrosion is a fundamental problem in electrochemistry and represents a mode of failure of technologically important materials. Understanding the basic mechanism of aqueous corrosion of metals such as Cu in presence of halide ions is hence essential. Using molecular dynamics simulations incorporating reactive force-field (ReaxFF), the interaction of copper substrates and chlorine under aqueous conditions has been investigated. These simulations incorporate effects of proton transfer in the aqueous media and are suitable for modeling the bond formation and bond breakage phenomenon that is associated with complex aqueous corrosion phenomena. Systematic investigation of the corrosion process has been carried out by simulating different chlorine concentration and solution states. The structural and morphological differences associated with metal dissolution in the presence of chloride ions are evaluated using dynamical correlation functions. The simulated atomic trajectories are used to analyze the charged states, molecular structure and ion density distribution which are utilized to understand the atomic scale mechanism of corrosion of copper substrates under aqueous conditions. Increased concentration of chlorine and higher ambient temperature were found to expedite the corrosion of copper. In order to study the effect of solution states on the corrosion resistance of Cu, partial fractions of proton or hydroxide in water were configured, and higher corrosion rate at partial fraction hydroxide environment was observed. When the Cl{sup -} concentration is low, oxygen or hydroxide ion adsorption onto Cu surface has been confirmed in partial fraction hydroxide environment. Our study provides new atomic scale insights into the early stages of aqueous corrosion of metals such as copper.

Jeon, B.; Sankaranarayanan, S. K. R. S.; van Duin, A. C. T.; Ramanathan, S. (Center for Nanoscale Materials); (Harvard Univ.); (Penn State Univ.)

2011-06-21

404

Thermal stability of ECAP processed pure copper  

Microsoft Academic Search

Microstructure and texture evolution of pure copper (99.95%) after equal-channel angular pressing (ECAP) with route Bc up to 12 passes and subsequent heat treatment were investigated. After deformation the samples were annealed at different temperatures. The deformed and annealed states were characterized by X-ray pole figures, electron back scatter diffraction (EBSD), TEM and microhardness tests. It was shown that the

X. Molodova; G. Gottstein; M. Winning; R. J. Hellmig

2007-01-01

405

Studies of sliding friction in compressed copper  

SciTech Connect

We present the results of simulations for sliding copper interfaces for pressures in the kilobar range. The velocity dependence and density dependence are discussed and the evolution of plastic damage is described. Density dependence embedded atom model (EAM) potentials are used to describe the atomic interactions. Simulations were typically for N=65,000 atoms and were carried out using molecular dynamics on massively parallel CM200 and CM5 platforms. A transition to a low friction state at high velocities is discussed.

Hammerberg, J.E.; Holian, B.L.; Zhou, S.J.

1995-09-01

406

Investigations of copper to stainless steel joints  

Microsoft Academic Search

Tensile and fracture behaviour of two copper alloys i.e. CuAl25 IG0 and CuCrZr and their joints with 316L(N) IG stainless steel produced by hot isostatic pressing (HIP) have been determined in unirradiated and neutron irradiated conditions. The experimental results and the numerical calculations indicate that tensile properties and fracture toughness values of the Cu\\/SS HIP joint specimens are reduced with

S Tähtinen; A Laukkanen; B. N Singh

2001-01-01

407

The Outer Electron Configuration in Metallic Copper  

Microsoft Academic Search

The effect on the atomic scattering factor of metallic copper of the 3d7.754s14p2.25 outer electron configuration, demanded by the Pauling valence of 5.50, is computed. Approximately a 6 percent lowering in intensity of the (111) reflection when compared with the atomic scattering factor computed on the basis of a Hartree-Fock calculation for the 3d104s1 configuration is predicted if the Pauling

A. I. Snow

1951-01-01

408

Elastic moduli of copper under compression  

SciTech Connect

Starting with a description of the electronic structure of copper, we have studied the zero temperature elastic moduli to 1 Mbar. We have used an empty-core model pseudopotential for the conduction electrons, treated the d-electron interactions in tight binding theory, and calculated the elastic moduli and their volume and pressure derivatives. The results are compared with experiment and with Full Potential Linear Muffin-Tin Orbital (FPLMTO) bandstructure calculations for the elastic moduli and their pressure derivatives.

Straub, G.K.; Wills, J.M.; Wallace, D.C.

1987-01-01

409

Pyrolysis of Waste Tires with Copper Nitrate  

Microsoft Academic Search

Influence of copper(?)nitrate(CN) on the pyrolysis of waste tires in 50 cm static batch reactor in a nitrogen atmosphere are studied. The products of pyrolysis was investigated with in situ Fourier transform infrared (FT-IR) spectroscopy as well as off-line gas chromatography\\/Mass spectrometry (GC-MS). The combination of FT-IR and GC\\/MS analysis was able to elucidate the effects of CN. Comparing with

QING-CAO KE-CHANG XIE; WEI-REN BAO; WEI-HUANG; JIAN-BING ZHAO

2004-01-01

410

Stress Corrosion cracking of copper single crystals  

Microsoft Academic Search

Constant extension rate tests have been carried out on copper single crystals in a sodium nitrite solution, using an applied\\u000a potential to accelerate the cracking. Crack velocities up to 30 nm per second were obtained at 30 ?C. The stress-corrosion\\u000a fracture surfaces are cleavage-like, with curved striations parallel to the crack front. If the dynamic straining is stopped,\\u000a the cracks

K. Sieradzki; R. L. Sabatini; R. C. Newman

1984-01-01

411

Sulfide scale catalysis of copper corrosion  

Microsoft Academic Search

The presence of soluble sulfides in a low alkalinity simulated drinking water increased copper pipe corrosion rates by more than one order of magnitude at pH 6.5 and more than two orders of magnitude at pH 9.2. Sulfides caused formation of a thick, black porous scale layer on pipes that did not significantly reduce pipe corrosion rates even after 9 months of

S. Jacobs; M. Edwards

2000-01-01

412

Upper critical field of copper molybdenum sulfide  

NASA Technical Reports Server (NTRS)

The upper critical field of sintered and sputtered copper molybdenum sulfide Cu(x)Mo6S8 was measured and found to exceed the Werthamer, Helfand, and Hohenberg (1966) value for a type II superconductor characterized by dirty limit, weak isotropic electron phonon coupling, and no paramagnetic limiting. It is suggested that the enhancement results from anisotropy or clean limit or both. Other ternary molybdenum sulfides appear to show similar anomalies.

Alterovitz, S. A.; Woollam, J. A.

1978-01-01

413

Copper catalysis in chloroform formation duringwater chlorination  

Microsoft Academic Search

The seminal work of Rook (Water Treat. Exam. 23(Part 2) (1974) 234) initiated a considerable body of research regarding the formation of trihalomethanes (THMs) and other by-products of chlorine-based disinfection. Since that time, a broad spectrum of compounds has been identified as precursors to THM formation. More recently, it has been demonstrated that the presence of copper in solution enhances

Ernest R. Blatchley; Dimitris Margetas; Ravikrishna Duggirala

414

Copper planar microcoils applied to magnetic actuation  

Microsoft Academic Search

Recent advances in microtechnology allow realization of planar microcoils. These components are integrated in MEMS as magnetic\\u000a sensor or actuator. In the latter case, it is necessary to maximize the effective magnetic field which is proportional to\\u000a the current passing through the copper track and depends on the distance to the generation microcoil. The aim of this work\\u000a was to

Marion Woytasik; Johan Moulin; Emile Martincic; Anne-Lise Coutrot; Elisabeth Dufour-Gergam

2008-01-01

415

EXAFS study of copper thiosemicarbazide complexes  

NASA Astrophysics Data System (ADS)

The present paper deals with the synthesis of transition metal Schiff base complexes of copper by chemical root method. The synthesized metal complexes have been studied by extended X-ray absorption fine structure (EXAFS) technique. The metal ligand bond length have been determined using LSS, Levy's and Lytle's methods. Bond-lengths have also been determined from the Fourier transform of the EXAFS data. Bond lengths determined from these methods are comparable to each other.

Mishra, Ashutosh; Mishra, S.; Ninama, S.; Pritam, A.

2014-09-01

416

New Technology for Electrorefining of Copper  

NASA Astrophysics Data System (ADS)

New electrorefining technology utilizes a novel manifold electrolyte inlet, which allows improving productivity and production in new and existing tankhouses at high current efficiency and very good cathode quality. Two installation examples—Montanwerke Brixlegg AG, Brixlegg, Austria (upgrade existing tankhouse) and Xiangguang Copper, Yanggu, China (new tankhouse)—demonstrate the use of current densities above 400 A/m2 at very high current efficiency in electrorefining.

Filzwieser, Andreas; Filzwieser, Iris; Konetschnik, Stefan

2012-11-01

417

Comparative Corrosion and Current Burst Testing of Copper and Aluminum Electrical Power Connectors  

Microsoft Academic Search

Crimped and mechanically bolted aluminum and copper connectors are commonly used for terminating industrial electrical power cables with ratings up to 600 V. Aluminum connectors are available for use with aluminum and copper conductors, and copper connectors are available for use with copper conductor only. The performance of copper and aluminum connectors was compared by conducting accelerated aging under corrosive

Ronald F. Frank; Christopher P. Morton

2007-01-01

418

Comparative corrosion and current burst testing of copper and aluminum electrical power connectors  

Microsoft Academic Search

Crimped and mechanically bolted aluminum and copper connectors are commonly used for terminating industrial electrical power cables with ratings up to 600 V. Aluminum connectors are available for use with aluminum or copper conductor, and copper connectors are available for use with copper conductor only. The performance of copper and aluminum connectors was compared by conducting accelerated aging under corrosive

Ron Frank; C. Morton

2005-01-01

419

Corrosion and Current Burst Testing of Copper and Aluminum Electrical Power Connectors  

Microsoft Academic Search

Crimped and mechanically bolted aluminum and copper connectors are commonly used for terminating industrial electrical power cables of ratings up to 600 V. Aluminum connectors are available for use with aluminum or copper conductor, and copper connectors are available for use with copper conductor only. The performance of copper and aluminum connectors was compared by accelerated aging under corrosive environmental

V. Buccholz; Ron Frank; Chris Morton

2006-01-01

420

Quality control parameters for Tamra (copper) Bhasma  

PubMed Central

Background: Metallic Bhasmas are highly valued and have their own importance in Ayurvedic formulations. To testify the Bhasmas various parameters have been told in Rasashastra classics. Tamra Bhasma (TB) with its different properties is used in the treatment of various diseases is quiet famous among the Ayurvedic physicians (Vaidyas). Objectives: The present study was carried out to set up the quality control parameters for the TB by making the use of classical tests along with advanced analytical tools. Settings and Design: Copper wire taken for the preparation of Bhasma was first analyzed for its copper content and then subjected to Shodhana, Marana and Amrutikarana procedures as per the classical references. Final product complied with all the classical parameters like Rekhapurnatwa, Varitaratwa etc. Materials and Methods: After complying with these tests TB was analyzed by advanced analytical techniques like particle size distribution (PSD) analysis, scanning electron microscopy (SEM), and inductive coupled plasma spectrometry (ICP). Results: PSD analysis of TB showed volumetric mean diameter of 28.70 ?m, 50% of the material was below 18.40 ?m size. Particle size less than 2?m were seen in SEM. 56.24 wt % of copper and 23.06 wt % of sulphur was found in ICP-AES. Heavy metals like cadmium, selenium were not detected while others like arsenic, lead and mercury were present in traces. Conclusions: These observations could be specified as the quality control parameters conforming to all the classical tests under the Bhasma Pariksha. PMID:23661863

Jagtap, Chandrashekhar Yuvaraj; Prajapati, Pradeepkumar; Patgiri, Biswajyoti; Shukla, Vinay J.

2012-01-01

421

Quench propagation delay due to copper wedges  

SciTech Connect

The superconducting magnet design style selected for the SSC dipoles is 16.6 m long and incorporates copper wedges in the windings in order to achieve the required magnetic field uniformity. Recent studies of quench propagation in a 4 m model, SLN-012 at BNL, have been carried out in order to prove the feasibility of self-protection for these magnets in the event of a quench. This feature would dispense with an active protection system like the one used in the Fermilab Energy Saver. These studies, however, require the knowledge of how the copper wedges affect the transverse spreading of normal zones needed in the self-protecting scheme. It is not clear that such information can be obtained with the short (1 m long) prototypes about to be tested since the time for the normal zone to cross over a wedge might be of the order of or longer than the time it takes for it to reach the other side of the wedge by propagation along the cable. Well instrumented long prototype magnets are months away from availability. Calculations that take into account the effect of the Kapton insulation, helium in the interstices and other significant details do not exist or have not been tested. Therefore we have measured the delay that the copper wedges introduce in the transverse (azimuthal) propagation of the normal zone in an experimental simulation of these magnets.

Kuchnir, M.; McInturff, A.D.; Hanft, R.W.; Mazur, P.O.

1986-01-01

422

Dispersion-strengthened copper-niobium composites  

SciTech Connect

GlidCop dispersion-strengthened copper is a family of engineered alloys which combine high strength, high thermal and electrical conductivities, and outstanding resistance to softening following exposure to elevated temperatures. A proprietary process based on GlidCop dispersion-strengthened copper technology improves mechanical properties through the addition of niobium. Two grades have been developed: Al-60 + NB1000 and Al-15 + NB1000. Each composite contains 10% niobium by weight, in the form of uniformly dispersed particles. The technology produces a uniform distribution of niobium in the internally oxidized, dispersion-strengthened copper powder. This powder can be consolidated in the same manner as conventional GlidCop Powder to produce a variety of mill shapes. The addition of 10% niobium to the Al-60 matrix increases strength and hardness with only minimal reduction in electrical conductivity. The room-temperature properties of Al-60 + NB1000 following exposure to 980 C (1,800 F), are compared with the properties of some commonly used RWMA welding materials which have also been exposed to elevated temperatures. While Al-60 + NB1000 has outstanding as-extruded mechanical properties, the cold workability of this material is limited. A cold-workable composite using the lower aluminum oxide Al-15 + NB1000 indicate that the properties of the as-extruded bar are improved by cold work, specifically drawing.

Troxell, J. [SCM Metal Products Inc., Research Triangle Park, NC (United States)

1995-06-01

423

Sorption of copper by olive mill residues.  

PubMed

A study on olive mill residues (OMR) as copper adsorbing material is reported in this work. A rough characterization of this waste material has been performed, by microanalysis and SEM pictures. Sorption tests with suspended OMR evidenced copper removal from solution, of about 60% in the investigated experimental conditions. The COD release in solution was also monitored during biosorption. Considering that it was significant, OMR washings with water were performed before biosorption. In this case the COD release in solution was reduced to less than 600 mg/L after two washings, while the OMR metal sorption properties did not change. Regenerated residues by acid solutions gave a copper removal of about 40%, in the same experimental conditions of the first adsorption test: regeneration with EDTA at different concentrations suggested that it presents a damage of adsorption active sites. On the other hand, the use of HCl and CaCl(2) led to completely regenerate the biosorbent material. Tests were also performed with a column filled with 80 g of OMR and the breakpoint was demonstrated to take place after that about 1L solution was treated in the investigated experimental conditions. Regeneration tests permitted to demonstrate that a concentration factor of about 2 can be obtained in no-optimized conditions, highlighting the possibility of using OMR for the treatment of metal bearing effluents. The main advantage of the process would be the "low cost" biosorbing material, considering that it represents a waste in the olive oil production. PMID:14604635

Vegliò, F; Beolchini, F; Prisciandaro, M

2003-12-01

424

Antiinflammatory reactivity of copper(I)-thionein.  

PubMed

In unseparated human blood the reactivity of yeast copper (I)-thionein on TPA-activated polymorphonuclear leukocytes was evaluated and compared with low Mr copper chelates exerting Cu2Zn2 superoxide dismutase mimetic activity. Cu, 18 microM, in the form of Cu-thionein was sufficient to inhibit the superoxide production of activated human blood phagocytes by 50%. Furthermore, the scavenging of hydroxyl radicals and singlet oxygen by Cu(I)-thionein was determined, using the 2-deoxyribose fragmentation assay induced by decaying K3CrO8 and the NADPH oxidation caused by UVA illuminated psoralen, respectively. The inhibitory reactivity of Cu-thionein in both assays was compared with that of serum proteins including albumin, ceruloplasmin, transferrin, and ferritin. The galactosamine/endotoxin-induced hepatitis in male NMRI mice was used to evaluate the antiinflammatory reactivity of Cu-thionein in vivo. The serum copper, superoxide dismutase, and sorbitol dehydrogenase concentrations, as well as the activity of polymorphonuclear leukocytes in unseparated blood seemed most appropriate to quantify the protective capacity of Cu-thionein in the course of an oxidative stress-dependent liver injury. The intraperitoneal application of 32.5 mumols/kg thionein-Cu limited this damage to 45%. PMID:2249884

Miesel, R; Hartmann, H J; Weser, U

1990-10-01

425

Antiinflammatory reactivity of copper(I)-thionein  

SciTech Connect

In unseparated human blood the reactivity of yeast copper (I)-thionein on TPA-activated polymorphonuclear leukocytes was evaluated and compared with low Mr copper chelates exerting Cu2Zn2 superoxide dismutase mimetic activity. Cu, 18 microM, in the form of Cu-thionein was sufficient to inhibit the superoxide production of activated human blood phagocytes by 50%. Furthermore, the scavenging of hydroxyl radicals and singlet oxygen by Cu(I)-thionein was determined, using the 2-deoxyribose fragmentation assay induced by decaying K3CrO8 and the NADPH oxidation caused by UVA illuminated psoralen, respectively. The inhibitory reactivity of Cu-thionein in both assays was compared with that of serum proteins including albumin, ceruloplasmin, transferrin, and ferritin. The galactosamine/endotoxin-induced hepatitis in male NMRI mice was used to evaluate the antiinflammatory reactivity of Cu-thionein in vivo. The serum copper, superoxide dismutase, and sorbitol dehydrogenase concentrations, as well as the activity of polymorphonuclear leukocytes in unseparated blood seemed most appropriate to quantify the protective capacity of Cu-thionein in the course of an oxidative stress-dependent liver injury. The intraperitoneal application of 32.5 mumols/kg thionein-Cu limited this damage to 45%.

Miesel, R.; Hartmann, H.J.; Weser, U. (Universitaet Tuebingen (Germany, F.R.))

1990-10-01

426

Crystal structures of copper(II) nitrate, copper(II) chloride, and copper(II) perchlorate complexes with 2-formylpyridine semicarbazone  

SciTech Connect

Compounds dinitrato(2-formylpyridinesemicarbazone)copper (I), dichloro(2-formylpyridinesemicarbazone) copper hemihydrate (II), and bis(2-formylpyridinesemicarbazone)copper(2+) perchlorate hydrate (III) are synthesized and their crystal structures are determined. In compounds I-III, the neutral 2-formylpyridine semicarbazone molecule (L) is tridentately attached to the copper atom via the N,N,O set of donor atoms. In compounds I and II, the Cu: L ratio is equal to 1: 1, whereas, in III, it is 1: 2. In complex I, the coordination sphere of the copper atom includes two nitrate ions with different structural functions in addition to the L ligand. The structure is built as a one-dimensional polymer in which the NO{sub 3} bidentate group fulfills a bridging function. The coordination polyhedron of the copper(2+) atom can be considered a distorted tetragonal bipyramid (4 + 1 + 1). Compound II has an ionic structure in which the main element is the [CuLCl{sub 2} . Cu(H{sub 2}O)LCl]{sup +} dimer. In the dimer, the copper atoms are linked via one of the {mu}{sub 2}-bridging chlorine atoms. The coordination polyhedra of the central atoms of the Cu(H{sub 2})LCl and CuLCl{sub 2} complex fragments are tetragonal bipyramid and tetragonal pyramid, respectively. In compound III, the copper atom is octahedrally surrounded by two L ligands in the mer configuration.

Chumakov, Yu. M. [Academy of Sciences of Moldova, Institute of Applied Physics (Moldova, Republic of); Tsapkov, V. I. [State University of Moldova (Moldova, Republic of); Antosyak, B. Ya. [Academy of Sciences of Moldova, Institute of Applied Physics (Moldova, Republic of); Bairac, N. N. [State University of Moldova (Moldova, Republic of); Simonov, Yu. A., E-mail: simonov.xray@phys.asm.md [Academy of Sciences of Moldova, Institute of Applied Physics (Moldova, Republic of); Bocelli, G. [National Research Council (IMEM-CNR), Institute of Materials for Electronics and Magnetism (Italy); Pahontu, E. [University of Medicine and Pharmacy (Romania); Gulea, A. P. [State University of Moldova (Moldova, Republic of)

2009-05-15

427

Copper Homeostasis at the Host-Pathogen Interface*  

PubMed Central

The trace element copper is indispensable for all aerobic life forms. Its ability to cycle between two oxidation states, Cu1+ and Cu2+, has been harnessed by a wide array of metalloenzymes that catalyze electron transfer reactions. The metabolic needs for copper are sustained by a complex series of transporters and carrier proteins that regulate its intracellular accumulation and distribution in both pathogenic microbes and their animal hosts. However, copper is also potentially toxic due in part to its ability to generate reactive oxygen species. Recent studies suggest that the macrophage phagosome accumulates copper during bacterial infection, which may constitute an important mechanism of killing. Bacterial countermeasures include the up-regulation of copper export and detoxification genes during infection, which studies suggest are important determinants of virulence. In this minireview, we summarize recent developments that suggest an emerging role for copper as an unexpected component in determining the outcome of host-pathogen interactions. PMID:22389498

Hodgkinson, Victoria; Petris, Michael J.

2012-01-01

428

Three distinct cases of copper deficiency in hospitalized pediatric patients.  

PubMed

Although copper deficiency is a rare occurrence in the developed world, attention should be given to the proper supplementation of minerals to at-risk pediatric patients. This study presents 3 distinct cases of copper deficiency in hospitalized patients aged 14 months, 6 years, and 12 years. Two patients had short bowel syndrome, requiring prolonged parenteral nutrition or complex intravenous fluid supplementation. The third patient was severely malnourished. Copper deficiency manifested in all of our patients as either microcytic anemia or pancytopenia with myelodysplastic syndrome. Copper deficiency is an important diagnosis to be considered in patients with prematurity, parenteral nutrition dependency, malabsorption, and/or those with malnutrition. More studies are needed to establish appropriate amounts of copper supplementation to replenish copper stores in deficient patients. PMID:22584540

Dembinski, Karolina; Gargasz, Anne Elizabeth; Dabrow, Sharon; Rodriguez, Lisa

2012-08-01

429

Effects of additives and chelating agents on electroless copper plating  

NASA Astrophysics Data System (ADS)

In this study, ethylenediaminetetraacetic acid (EDTA), triethanolamine (TEA), and ethylenediamine (En) were adopted herein as additives or chelating agents in electroless copper plating, with formaldehyde as the reduction agent. Linear sweep voltammetry was successfully applied to analyze the potential shift of copper complexes and the adsorption capability of chelating agents on a surface. Moreover, the grain size and surface roughness of copper were investigated using atomic force microscopy (AFM). The experimental results for a dual-chelating-agent system indicated that EDTA plays an important role in chelating, while the main effect of TEA is adsorption on copper surfaces to inhibit formaldehyde oxidation. Meanwhile, ethylenediamene is a prominent refining agent owing to its markedly higher adsorption strength on copper surfaces than formaldehyde and TEA. The analyses including linear sweep voltammetry, AFM, and XRD are effective to explore the effect of chelating agents and additives on electroless copper plating and deposits.

Lin, Yi-Mao; Yen, Shi-Chern

2001-07-01

430

Scale formation on polypropylene and copper tubes  

NASA Astrophysics Data System (ADS)

The scaling behaviors of polypropylene and copper were compared quantitatively under accelerated conditions (distilled water or high supersaturation) and more realistic conditions (potable water and low supersaturation). In addition, the effect of surface roughness on scaling on polypropylene surfaces was studied. Polypropylene tubes, with different degrees of root mean square roughness on the inner surfaces created by machining with abrasives, were exposed to a laminar flow of distilled water supersaturated with respect to CaCO 3. Nucleation site density, i.e. the number of crystals per unit surface area, on the machined surfaces was two to ten times that on the native surfaces. However, the nucleation site density was not correlated to the roughness of the samples. These results suggest that nanometer-sized surface imperfections (e.g. steps and grooves) formed during the roughening process, rather than roughness, are responsible for the enhanced nucleation on the machined PP surfaces. Scaling behaviors on polypropylene and copper were compared by exposing the surfaces to laminar flows of distilled water and potable water highly supersaturated with respect to CaCO3 (supersaturation, S > 9) for 0.5 to 4 hours, and distilled water mildly supersaturated (S = 4.8) for 1.5 to 15 hours. The scaling rate of polypropylene was at least 40 higher than that of copper after exposure to the distilled water at S ¿ 9. The scaling rates of polypropylene and copper were not statistically different after exposure to either mildly supersaturated distilled water (S = 4.8) or highly supersaturated potable water. Polypropylene and copper tubes were also exposed to a laminar flow of mildly supersaturated potable water at 40°C (S = 5 with respect to CaCO3) for 1 to 8 weeks. Calcium phosphate was a major component of the calcium-rich scale deposit, a result that is linked to the presence of trace amount of phosphate ions in the water and the inhibiting effect (for CaCO3 formation) of other ions present. Under these conditions, Cu oxidizes and scales at a higher rate than PP.

Wu, Zhen

431

Yttria-Stabilized Zirconia Supported Copper Oxide Catalyst  

Microsoft Academic Search

Copper oxide was supported on yttria-stabilized zirconia (YSZ) and ?-alumina, respectively, using impregnation methods. The reducibility and characteristics of the supported copper oxide catalysts with various copper loadings were revealed and determined by temperature-programmed reduction (TPR) and electron paramagnetic resonance (EPR), respectively. For CuO\\/?–alumina catalyst, only two peaks were found in the TPR patterns. One with lower peak temperature has

Wei-Ping Dow; Yu-Piao Wang; Ta-Jen Huang

1996-01-01

432

DOES COPPER DISSOLUTION IMPACT THROUGH-HOLE SOLDER JOINT RELIABILITY?  

Microsoft Academic Search

The process issues relating to high copper dissolution rates have been well documented within the industry. The copper dissolution rates of SAC305\\/405 plus many of the leading alternative lead-free wave alloys have been characterized and pin-through-hole rework process windows assessed. One remaining gap within the industry is the understanding of how copper dissolution or thinning of the through-hole barrel wall\\/knee

Craig Hamilton; Polina Snugovsky; Mario Moreno; Teng Hoon Ng; Juthathip Fangkangwanwong; Celestica Toronto; Celestica Mexico; Matthew Kelly; Marie Cole

2009-01-01

433

Crystal Structures of Cisplatin Bound to a Human Copper Chaperone  

SciTech Connect

Copper trafficking proteins, including the chaperone Atox1 and the P{sub 1B}-type ATPase ATP7B, have been implicated in cellular resistance to the anticancer drug cisplatin. We have determined two crystal structures of cisplatin-Atox1 adducts that reveal platinum coordination by the conserved CXXC copper-binding motif. Direct interaction of cisplatin with this functionally relevant site has significant implications for understanding the molecular basis for resistance mediated by copper transport pathways.

Boal, Amie K.; Rosenzweig, Amy C.; (NWU)

2010-08-16

434

BIOCHEMISTRY: Delivering Copper Inside Yeast and Human Cells  

NSDL National Science Digital Library

Access to the article is free, however registration and sign-in are required. In their Perspective, Valentine and Gralla summarize the emerging picture of a series of transport proteins that shuttle the toxic metal, copper, safely around the cell, delivering it to nascent enzymes that rely on copper for proper catalytic function. A report in this week's issue by Pufahl et al. describes the delivery of copper to Fet3 by Atx1.

Joan Selverstone Valentine (University of California at Los Angeles;Department of Chemistry and Biochemistry); Edith Butler Gralla (University of California at Los Angeles;Department of Chemistry and Biochemistry)

1997-10-31

435

The industrial separation of copper and arsenic as sulfides  

NASA Astrophysics Data System (ADS)

At the Kennecott Utah copper smelter in Magna, Utah, bleed streams from the refinery tankhouse and precious-metals plant are combined with smelter weak acid and electrostatic precipitator dust to produce leach solutions containing copper and impurities. Copper and arsenic are precipitated from the solutions as sulfides in a two-stage continuous process that enables excess arsenic to be removed from the circuit and routed to hazardous waste disposal as a highly concentrated material.

Gabb, P. J.; Davies, A. L.

1999-09-01

436

Electrocatalytic CO2 Conversion to Oxalate by a Copper Complex  

Microsoft Academic Search

Global warming concern has dramatically increased interest in using CO2 as a feedstock for preparation of value-added compounds, thereby helping to reduce its atmospheric concentration. Here, we describe a dinuclear copper(I) complex that is oxidized in air by CO2 rather than O2; the product is a tetranuclear copper(II) complex containing two bridging CO2-derived oxalate groups. Treatment of the copper(II) oxalate

Raja Angamuthu; Philip Byers; Martin Lutz; Anthony L. Spek; Elisabeth Bouwman

2010-01-01

437

Managing the use of copper-based antifouling paints.  

PubMed

Copper is the biocide of choice for present-day antifouling (AF) paints. It is also a major source of copper loading in to the marine environment and, as such, might cause local copper levels to exceed water quality criteria. The present study is multifaceted and looks into the overall impact of copper-based AF paints on copper concentrations along a 64-km stretch of the Indian River Lagoon and at Port Canaveral, Florida. This preliminary study is one of the first to outline issues and present background evidence on the current status of copper and copper-based AF usage in Florida and to address the need for management. Previous measurements of copper levels in these waters show a history of copper contamination close to marinas, boatyards, and at Port Canaveral that often exceed state and federal water quality standards. Further, we estimate that the total annual copper input into the Indian River Lagoon is between 1.7 tons/year (sailboats) and 2.1 tons/year (powerboats) from boats in 14 marinas. We estimate the copper input into Port Canaveral to be about 1.4 tons/year from seven cruise ships. A brief survey of marina operators and boat owners revealed attitudes and practices associated with AF paint usage that ranged from excellent to inferior. Management recommendations are made for a proactive approach to improving AF paint selection and application, assessing the environmental status of copper, and redefining existing management practices for sustainable AF paint usage and environmental health. PMID:17253094

Srinivasan, Mridula; Swain, Geoffrey W

2007-03-01

438

Managing the Use of Copper-Based Antifouling Paints  

NASA Astrophysics Data System (ADS)

Copper is the biocide of choice for present-day antifouling (AF) paints. It is also a major source of copper loading in to the marine environment and, as such, might cause local copper levels to exceed water quality criteria. The present study is multifaceted and looks into the overall impact of copper-based AF paints on copper concentrations along a 64-km stretch of the Indian River Lagoon and at Port Canaveral, Florida. This preliminary study is one of the first to outline issues and present background evidence on the current status of copper and copper-based AF usage in Florida and to address the need for management. Previous measurements of copper levels in these waters show a history of copper contamination close to marinas, boatyards, and at Port Canaveral that often exceed state and federal water quality standards. Further, we estimate that the total annual copper input into the Indian River Lagoon is between 1.7 tons/year (sailboats) and 2.1 tons/year (powerboats) from boats in 14 marinas. We estimate the copper input into Port Canaveral to be about 1.4 tons/year from seven cruise ships. A brief survey of marina operators and boat owners revealed attitudes and practices associated with AF paint usage that ranged from excellent to inferior. Management recommendations are made for a proactive approach to improving AF paint selection and application, assessing the environmental status of copper, and redefining existing management practices for sustainable AF paint usage and environmental health.

Srinivasan, Mridula; Swain, Geoffrey W.

2007-03-01

439

Copper Oxide Impregnated Textiles with Potent Biocidal Activities  

Microsoft Academic Search

Impregnation or coating of cotton and polyester fibers with cationic copper endows them with potent broad-spectrum antibacterial, antiviral, antifungal, and antimite properties (Borkow, G. and Gabbay, J. (2004). Putting Copper into Action: Copper-impregnated Products with Potent Biocidal Activities, FASEB Jounal, 18(14): 1728-1730). This durable platform technology enables the mass production of woven and non-woven fabrics, such as sheets, pillow covers,

Jeffrey Gabbay; Gadi Borkow; Joseph Mishal; Eli Magen; Richard Zatcoff; Yonat Shemer-Avni

2006-01-01

440

INDUSTRIAL COPPER INTOXICATION IN SHEEP: CLINICAL AND PATHOLOGICAL FINDINGS  

Microsoft Academic Search

Elgerwi A., J. Bíre‰, M. Levkut: Industrial Copper Intoxication in Sheep: Clinical and Pathological Findings. Acta Vet. Brno 1999, 68: 197-202. Experiments were carried out to investigate the clinical symptoms and pathological and histological findings resulting from industrial copper intoxication in improved Vallachian sheep (five-year-old females) that had been reared for five years in the deposition area of a copper-

A. ELGERWI; J. BÍRE; M. LEVKUT

1999-01-01

441

Kinetics of copper drift in low-? polymer interlevel dielectrics  

Microsoft Academic Search

This paper addresses the drift of copper ions (Cu+) in various low-permittivity (low-?) polymer dielectrics to identify copper barrier requirements for reliable interconnect integration in future ULSI. Stressing at temperatures of 150-275°C and electric fields up to 1.5 MV\\/cm was conducted on copper-insulator-silicon capacitors to investigate the penetration of Cu+ into the polymers. The drift properties of Cu+ in six

Alvin L. S. Loke; Jeffrey T. Wetzel; Paul H. Townsend; Tsuneaki Tanabe; Raymond N. Vrtis; Melvin P. Zussman; Devendra Kumar; Changsup Ryu; S. Simon Wong

1999-01-01

442

Using polyethylene glycols as alternative inhibitors in copper electrorefining  

NASA Astrophysics Data System (ADS)

Polyethylene glycols (PEGs) with well-defined molecular weight ranges are interesting alternative additives for copper electrorefining. In comparison to glue, PEGs offer high thermal stability and slow chemical decomposition at higher temperatures, with high cathodic polarization. Thosefactors are advantages for an optimized process control in copper electrorefining. Investigations into cathodic polarization as a function of molecular weight and concentration at 500 A/m2, and also into the half-life of PEGs, were conducted in typical copper electrolyte.

Stelter, Michael; Bombach, Hartmut; Nesterov, Nikolay

2002-04-01

443

Leaching of copper converter slag with Aspergillus niger culture filtrate  

Microsoft Academic Search

Leaching of copper converter slag of M\\/s Hindustan Copper Ltd, Ghatshila (Bihar, India) was carried out usingAspergillus niger culture filtrate. The effects of the duration of leaching, temperature, pulp density and the addition of hydrochloric acid were studied.A. niger culture filtrate solubilized metals from the converter slag at levels of 18.70% copper, 7.40% nickel and 4.00% cobalt. Addition of hydrochloric

Lal Bihari Sukla; Rabi Narayan Kar; Vinita Panchanadikar

1992-01-01

444

Thin film solar cells. (Latest citations from the NTIS bibliographic database). Published Search  

SciTech Connect

The bibliography contains citations concerning research and development of high-efficiency and low-cost thin film solar cells. References discuss the design and fabrication of silicon, gallium arsenide, copper selenide, indium selenide, cadmium telluride, and copper indium selenide solar cells. Applications in space and utilities are examined. Government projects and foreign technology are also reviewed. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

NONE

1997-11-01

445

Estimate of undiscovered copper resources of the world, 2013  

USGS Publications Warehouse

Using a geology-based assessment methodology, the U.S. Geological Survey estimated a mean of 3,500 million metric tons (Mt) of undiscovered copper among 225 tracts around the world. Annual U.S. copper consumption is 2 Mt; global consumption is 20 Mt. The USGS assessed undiscovered copper in two deposit types that account for about 80 percent of the world's copper supply. Results of the assessment are provided by deposit type for 11 regions. Approximately 50 percent of the global total occurs in South America, South Central Asia and Indochina, and North America combined.

Johnson, Kathleen M.; Hammarstrom, Jane M.; Zientek, Michael L.; Dicken, Connie

2014-01-01

446

A new environmentally-preferred copper corrosion inhibitor  

SciTech Connect

Copper and its alloys have excellent heat transfer properties and are widely used in industrial cooling water systems. A corrosion inhibitor, however, is needed to prevent equipment failures and to reduce the discharge of toxic copper compounds into the environment. Although azoles such as benzotriazole and tolyltriazole have been used to protect copper alloys from corrosion, they react with oxidizing halogens which are commonly used to control microbiological activity. Their reaction with chlorine, for example, produces species that are not protective to copper. The inhibitor films formed on copper also deteriorate in the presence of halogens, leading to high copper corrosion rates. A number of new azole derivatives have been discovered that provide superior copper protection in halogenated cooling water systems. A new halogen resistant azole (HRA) has been developed which has minimal reactivity with halogens and protects copper when chlorine is present. As a result, elimination of copper-induced pitting corrosion on mild steel was also achieved. This novel material has numerous environmental benefits. Laboratory and field results are presented.

Cheng, L.; May, R.C.; Given, K.M. [BetzDearborn Inc., Trevose, PA (United States)

1999-11-01

447

Effect of a copper gradient on plant community structure.  

PubMed

Vegetation data including plant cover, biomass, species richness, and vegetation height was sampled on a copper-contaminated field with total copper contents varying from 50 to almost 3,000 mg/kg soil. The field was covered by early succession grassland dominated by Agrostis stolonifera. Plant cover, biomass, species richness, and vegetation height generally decreased with increasing copper content, although the highest biomass was reached at intermediate copper concentrations. Multivariate statistical analyses showed that plant community composition was significantly correlated with soil copper concentration and that community composition at soil copper concentrations above 200 mg/kg differed significantly from community composition at lower copper levels. Comparison of single-species (Black Bindweed, Fallopia convolvulus) performance at the field site and in laboratory tests involving field soil and spiked soil indicates that the laboratory tests conventionally applied for risk assessment purposes do not overestimate copper effects. Interaction between copper and other stressors operating only in the field probably balance the higher bioavailability in spiked soil. PMID:16566159