Search NASA⌕ Search

SEARCH · Search NASA

Results for “COPPER 71”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2011

Nuclear Data Sheets for A = 71

The evaluated spectroscopic data are presented for experimentally known nuclides of mass 71 (Mn,Fe,Co,Ni,Cu,Zn,Ga,Ge,As,Se,Br,Kr). Excited-state data are nonexistent for {sup 71}Mn, {sup 71}Fe, {sup 71}Co and {sup 71}Kr. Significant new data have been added since the last evaluation of A=71 nuclides by M. Bhat (1993Bh02). Excited states are now known in {sup 71}Ni and {sup 71}Cu, and enhanced information about high-spin excitations is available for {sup 71}Ga, {sup 71}As and {sup 71}Br. The decay schemes of radioactive isotopes {sup 71}Mn and {sup 71}Fe are not known at all, and those for {sup 71}Co, {sup 71m}Ni and {sup 71}Kr are not known well. For the decay of {sup 71}Cu, {sup 71g}Ni, and {sup 71}Br, extensive data are available, but in the opinion of the evaluators the decay schemes still seem incomplete. This work supersedes earlier full evaluations of A=71 published by 1988Bh01, 1979Ke06 and 1973Al33, and the last one published in 'update' mode by 1993Bh02.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2011

Hyperfine field and hyperfine anomalies of copper impurities in iron

A new value for the hyperfine magnetic field of copper impurities in iron is obtained by combining resonance frequencies from experiments involving {beta}-NMR on oriented nuclei on {sup 59}Cu, {sup 69}Cu, and {sup 71}Cu with magnetic moment values from collinear laser spectroscopy measurements on these isotopes. The resulting value, i.e., B{sub hf}(CuFe) = -21.794(10) T, is in agreement with the value adopted until now but is an order of magnitude more precise. It is consistent with predictions from ab initio calculations. Comparing the hyperfine field values obtained for the individual isotopes, the hyperfine anomalies in Fe were determined to be {sup 59{Delta}69}=0.15(9)% and {sup 71{Delta}69}=0.07(11)%.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Electronic cooling using thermoelectric devices

Thermoelectric coolers or Peltier coolers are used to pump heat in the opposite direction of the natural heat flux. These coolers have also been proposed for electronic cooling, wherein the aim is to pump heat in the natural heat flux direction and from hot spots to the colder ambient temperature. In this manuscript, we show that for such applications, one needs to use thermoelectric materials with large thermal conductivity and large power factor, instead of the traditionally used high ZT thermoelectric materials. We further show that with the known thermoelectric materials, the active cooling cannot compete with passive cooling, and one needs to explore a new set of materials to provide a cooling solution better than a regular copper heat sink. We propose a set of materials and directions for exploring possible materials candidates suitable for electronic cooling. Finally, to achieve maximum cooling, we propose to use thermoelectric elements as fins attached to copper blocks.

42 ENGINEERING↗
DOE OSTI2014

Spectral studies of copper(II) complexes of 6-(3-thienyl) pyridine-2-thiosemicarbazone

Two novel copper(II) complexes [Cu(HL)Cl]Cl.H{sub 2}O (1) and [Cu(L)NO{sub 3}]Ðœ‡H{sub 2}O (2) of the three NNS donor thiosemicarbazone ligand 6-(3-thienyl) pyridine-2-thiosemicarbazone have been synthesized. The ligand and its copper(II) complexes were characterized by elemental analysis (C, H, N, and S), FT-IR, UV-visible, magnetic susceptibility and molar conductance. The thiosemicarbazone is present either as the thione form in complex 1 or as thiol form in complex 2 and is coordinated to copper(II) atom via the pyridine nitrogen atom, the azomethine nitrogen atom and the sulfur atom. The physicochemical and spectral data suggest square planar geometry for copper(II) atoms.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2017

Study of a DC gas discharge with a copper cathode in a water flow

A dc gas discharge between copper electrodes in the current range of 5–20 А was studied experimentally. The discharge gap length was varied within 45–70 mm. The cathode was a 10-mm-diameter rod placed in the water flowing out from a dielectric tube. Three discharge configurations differing in the position of the cathode upper end with respect to the water surface were considered: (i) above water; (ii) flush with the water surface, and (iii) under water. The electric and optical characteristics of the discharge in the second configuration were studied in more detail. It is established that the discharge properties are similar to those of an electric arc. Considerable cathode erosion was observed in the third configuration. It is revealed that fine-dispersed copper grains form in the course of erosion.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2015

Accelerated light-induced degradation for detecting copper contamination in p-type silicon

Copper is a harmful metal impurity that significantly impacts the performance of silicon-based devices if present in active regions. In this contribution, we propose a fast method consisting of simultaneous illumination and annealing for the detection of copper contamination in p-type silicon. Our results show that, within minutes, such method is capable of producing a significant reduction of the minority carrier lifetime. A spatial distribution map of copper contamination can then be obtained through the lifetime values measured before and after degradation. In order to separate the effect of the light-activated copper defects from the other metastable complexes in low resistivity Cz-silicon, we carried out a dark anneal at 200 °C, which is known to fully recover the boron-oxygen defect. Similar to the boron-oxygen behavior, we show that the dark anneal also recovers the copper defects. However, the recovery is only partial and it can be used to identify the possible presence of copper contamination.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2015

Shock wave convergence in water with parabolic wall boundaries

The convergence of shock waves in water, where the cross section of the boundaries between which the shock wave propagates is either straight or parabolic, was studied. The shock wave was generated by underwater electrical explosions of planar Cu wire arrays using a high-current generator with a peak output current of ∼45 kA and rise time of ∼80 ns. The boundaries of the walls between which the shock wave propagates were symmetric along the z axis, which is defined by the direction of the exploding wires. It was shown that with walls having a parabolic cross section, the shock waves converge faster and the pressure in the vicinity of the line of convergence, calculated by two-dimensional hydrodynamic simulations coupled with the equations of state of water and copper, is also larger.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2011

Plume dynamics and cluster formation in laser-ablated copper plasma in a magnetic field

Laser-ablated copper plasma plume expanding in a nonuniform magnetic field and ambient gas is investigated to understand plume dynamics using optical emission spectroscopy and fast imaging of the plume. A peculiar oscillatory behavior of the plume observed in magnetic field is discussed. The appearance and enhancement of Cu{sub 2} (A-X) band in ambient gas and in the presence of magnetic field is reported. The presence of magnetic field favors the formation of copper clusters in the expanding plumes.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2014

Formation kinetics of copper-related light-induced degradation in crystalline silicon

Light-induced degradation (LID) is a deleterious effect in crystalline silicon, which is considered to originate from recombination-active boron-oxygen complexes and/or copper-related defects. Although LID in both cases appears as a fast initial decay followed by a second slower degradation, we show that the time constant of copper-related degradation increases with increasing boron concentration in contrast to boron-oxygen LID. Temperature-dependent analysis reveals that the defect formation is limited by copper diffusion. Finally, interface defect density measurements confirm that copper-related LID is dominated by recombination in the wafer bulk.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2015

Application of diffuse discharges of atmospheric pressure formed by runaway electrons for modification of copper and stainless steel surface

The results of studies devoted to the influence of a runaway electron pre-ionized diffuse discharge (REP DD) formed in air and nitrogen at atmospheric pressure on the surface of copper and stainless steel are presented. Nanosecond high-voltage pulses were used to obtain REP DD in different gases at high pressures in a chamber with a flat anode and a cathode possessing a small radius of curvature. This mode of discharge was implemented owing to the generation of runaway electrons and X-rays. The conditions under which the surface of copper and stainless steel was cleaned from carbon and oxidized are described.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2014

Surface plasmon enhanced photoluminescence from copper nanoparticles: Influence of temperature

Anomalous temperature dependence of surface plasmon enhanced photoluminescence from copper nanoparticles embedded in a silica host matrix has been observed. The quantum yield of photoluminescence increases as the temperature increases. The key role of such an effect is the interplay between the surface plasmon resonance and the interband transitions in the copper nanoparticles occurring at change of the temperature. Namely, the increase of temperature leads to the red shift of the resonance. The shift leads to increase of the spectral overlap of the resonance with photoluminescence band of copper as well as to the decrease of plasmon damping caused by interband transitions. Such mechanisms lead to the increase of surface plasmon enhancement factor and, consequently, to increase of the quantum yield of the photoluminescence.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Spatial Modeling of Geometallurgical Properties: Techniques and a Case Study

High-resolution spatial numerical models of metallurgical properties constrained by geological controls and more extensively by measured grade and geomechanical properties constitute an important part of geometallurgy. Geostatistical and other numerical techniques are adapted and developed to construct these high-resolution models accounting for all available data. Important issues that must be addressed include unequal sampling of the metallurgical properties versus grade assays, measurements at different scale, and complex nonlinear averaging of many metallurgical parameters. This paper establishes techniques to address each of these issues with the required implementation details and also demonstrates geometallurgical mineral deposit characterization for a copper–molybdenum deposit in South America. High-resolution models of grades and comminution indices are constructed, checked, and are rigorously validated. The workflow demonstrated in this case study is applicable to many other deposit types.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

Mercury Speciation via Direct Mercury Analyzer

Mercury has no known biological role, but is present in every living thing and widespread in the environment. As mercury enters an aqueous system, it is subject to methylation or demethylation. Methylmercury selectively partitions into biota and biomagnifies through the food chain. Nearly all methylmercury exposures in the U.S. occur through eating fish and shellfish that contain higher levels of methylmercury. Methyl mercury and other organomercury compounds are more toxic than inorganic mercury. Thus, monitoring and understanding mercury speciation are key to effective environmental management. It is particularly important to be able to separate and measure bioaccumulative-toxic species of mercury such as methyl mercury. We are developing a protocol for utilizing the Direct Mercury Analyzer (DMA-80) for mercury speciation of water samples and to monitor methylmercury (meHg). Objectives: - Advance the understanding of the performance of the direct mercury analysis (DMA) under a range of DOE relevant water chemistry conditions to quantify total mercury: - Demonstrate the applicability of DMA to analysis of typical DOE high level liquid 'tank' waste samples using nonradioactive simulants; Test innovative sorbents to extend the range of the direct mercury analyzer to environmental concentration levels. - Perform scoping tests to demonstrate proof of principle for the chemical reduction amalgamation modular microcolumns for mercury speciation: Examine various microcolumn configurations and document speciation performance for typical DOE high level liquid 'tank' waste samples using nonradioactive simulants; Perform tests to examine extending the speciation paradigm to environmental concentration levels. General Method: all samples analyzed using a direct mercury analyzer (DMA 80) which automates the following steps: 1) pyrolysis to release the mercury, 2) catalysis to convert all mercury to elemental, 3) amalgamation to trap the mercury, 4) desorption to release the mercury as a pulse and 5) spectroscopy to detect the mercury.. Instrument analyzes all mercury species in solids and liquids. The DMA 'eliminates' sample preparation, reduces labor, decreases waste, and results in more practical and cost effective methods. To test the performance of the DMA for DOE relevant conditions, we analyzed samples representative of at high (mg/L) tank waste concentrations in water and in diluted tank waste simulant and analyzed samples representative of environmental (ng/L levels) in water. High concentration samples were analyzed directly in the instrument. Low concentration samples were analyzed by concentrating the mercury onto sorbents such as silica thiol or a mixture of silica thiol and copper. The concentration was performed using microcolumns and placing the columns into the DMA (see below) or by mixing the sorbent into the bulk sample and then filtering ad analyzing the filter in the DMA. Speciation Methods: The speciation tests were based on the selective reduction of inorganic mercury ions - Hg{sup (+} {sup or} {sup 2+)} - to elemental mercury - Hg(0). The elemental mercury is then trapped by amalgamation into the metal. These reactions do not impact methyl mercury allowing for separation. All reactions were performed using powdered elemental copper. To demonstrate proof-of-principle for the selective collection of inorganic mercury, samples were exposed to different amounts of powdered copper (and a control with no copper). This was done using microcolumns and a vacuum box. The columns were placed directly on the DMA for analysis. All materials and conditions were tested using solutions of both inorganic mercury and methyl mercury and all trials were in triplicate. Results and Observations: Validated DMA for high concentration Hg samples such as DOE tank waste: - Liquid inHg - samples were stable on autosampler carousel and results were accurate; - Liquid meHg - samples required a stabilizer. Si-Thiol (0.02 g) in the sample boat generated reliable meHg results. Stabilizer can be added for routine operations. Successful 'proof of principal' in extending DMA range to near environmental levels - using both microcolumns and filtration; - Filtration - Adding Si-Thiol (0.5 g) to sample extracted both inHg and meHg and preserved sample. Handling filters was labor intensive. - Microcolumns - best performance using a combination of copper and Si-Thiol - columns clogged and flowed slowly in some cases; - Practical limit may be in the range of 1 to 5 ng/L due to blanks; - Path Forward - Test additional packing materials and methods to improve flow and consistency, and approaches to minimize blanks. Successful 'proof of principal' for Hg speciation using chemical reduction and amalgamation; - Copper microcolumns (0.5 g Cu) selectively trapped inHg for high concentration mercury samples; - Copper microcolumns (0.5 g Cu selectively trapped inHg for large volume samples at environmental concentrations; - Some sorption of me Hg so that separations not quantitative; - Path Forward - test additional packing materials and alternate eluents to better trap inHg and minimize meHg retention in column.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2013

Negative magnetodielectric effect in CaCu{sub 3}Ti{sub 4}O{sub 12}

Real part of complex relative dielectric value is relatively decreased as large as ∼5 % from 50 K to 200 K in CaCu{sub 3}Ti{sub 4}O{sub 12}, by applying a 6-T static magnetic field. CaCu{sub 3}Ti{sub 4}O{sub 12} is thus implied primarily by the negative magnetodielectric effect, as a unified dielectric system in which 1-D finite dipole chains of B-site titanium ions, coexist with a collective of polaron-like 3d-electrons of A-site copper ions: the dipole chains are thermally activated for lattice ionic polarization above 50 K, and suppressed by the short-range hop of these quasi-particles, while their long-range movement are for bulk electronic polarization above 151 K.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2015

Morphological features of the copper surface layer under sliding with high density electric current

Conductivity and wear intensity of copper under the influence of dry friction and electric current with contact density higher 100 A/cm{sup 2} are presented. It is shown that an increase in hardness and heat outflow from a friction zone leads to the reduction of wear intensity and current contact density increase corresponding to the beginning of catastrophic wear. Structural changes, such as the formation of FeO oxide and α-Fe particles in the copper surface layer, have also been found. It is observed that a worn surface is deformed according to a viscous liquid mechanism. Such singularity is explained in terms of appearance of high-excited atomic states in deforming micro-volumes near contact spots that lead to easy stress relaxation by local plastic shears in the vicinity of stress concentrators. In common this effect allows to achieve high wear resistance.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2021

Isolated copper single sites for high-performance electroreduction of carbon monoxide to multicarbon products

Electrochemical carbon monoxide reduction is a promising strategy for the production of value-added multicarbon compounds, albeit yielding diverse products with low selectivities and Faradaic efficiencies. Here, copper single atoms anchored to Ti 3 C 2 T x MXene nanosheets are firstly demonstrated as effective and robust catalysts for electrochemical carbon monoxide reduction, achieving an ultrahigh selectivity of 98% for the formation of multicarbon products. Particularly, it exhibits a high Faradaic efficiency of 71% towards ethylene at -0.7 V versus the reversible hydrogen electrode, superior to the previously reported copper-based catalysts. Besides, it shows a stable activity during the 68-h electrolysis. Theoretical simulations reveal that atomically dispersed Cu–O 3 sites favor the C–C coupling of carbon monoxide molecules to generate the key *CO-CHO species, and then induce the decreased free energy barrier of the potential-determining step, thus accounting for the high activity and selectivity of copper single atoms for carbon monoxide reduction.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Trap-assisted large gain in Cu{sub 2}O/C{sub 60} hybrid ultraviolet/visible photodetectors

Photomultiplication-type ultraviolet (UV)/visible photodetectors (PDs) are demonstrated in an electrodeposited Cu{sub 2}O/C{sub 60} hybrid structure. These simple organic/inorganic hybrid PDs exhibit external quantum efficiencies (EQEs) of 1.1 × 10{sup 4}% under illumination of 365 nm UV light at −3 V, indicating a large gain of photocurrent for these devices. Such an EQE is one of the highest values among the reported organic/inorganic hybrid PDs at the same voltage. Cu{sub 2}O and C{sub 60} are found to play different roles in realizing the photomultiplication. Copper vacancies are proposed as the defects in the electrodeposited Cu{sub 2}O layers, which can trap photogenerated holes. Such trapped holes will trigger the injection of multiple electrons and hence result in the photocurrent gain of the devices while C{sub 60} primarily acts as a light absorption media to provide free holes.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗