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Microscopic theory of charges density wave instability in NbSe/sub 2/

Description: The microscopic theory of Sinha and Harmon for electronically driven lattice instabilities is used to explain the ''Kohn-like'' anomalies in the ..sigma../sub 1/ phonon branch and the observed incommensurate superlattice Bragg peak in 2H-NbSe/sub 2/, characteristic of the charge density wave at low temperatures in the neutron scattering experiments of Moncton et al. In accordance with the APW and LCAO band-structure calculations of Mattheiss of 2H-NbSe/sub 2/, the presence o… more
Date: January 1, 1977
Creator: Das, S G; Sinha, S K & Wakabayashi, N
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Development of superconductors for applications in high-field, high-current-density magnets for fusion research

Description: The development of large-bore, high-field magnets for fusion energy applications requires a system approach to both magnet and conductor design. At Lawrence Livermore National Laboratory (LLNL), the criteria used to choose superconductors include: strain tolerance, radiation tolerance, heat removal, stability, fabricability, and cost. We report on the performance of industrially produced, prototype, Ti-modified Nb/sub 3/Sn wires developed with LLNL support. Wire performance characteristics eval… more
Date: September 26, 1986
Creator: Summers, L. T. & Miller, J. R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Condensed-matter research at the Los Alamos pulsed neutron source (WNR)

Description: The experimental program at the WNR in condensed matter research at present is aimed principally at utilizing the high epithermal neutron flux available at a spallation neutron source. Interesting new results have been obtained in several areas including hydrogen vibrations in metals, chemical vibrational spectroscopy and the structure of liquids. For example, extensive vibrational spectra were obtained of hydrogen in Nb which could be described in terms of a three-dimensional localized anharmo… more
Date: January 1, 1982
Creator: Eckert, J.
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Partner: UNT Libraries Government Documents Department
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Specific-heat measurements on high-T/sub c/ A-15's

Description: Specific heat measurements for the seven high T/sub c/ A-15's are reviewed. Derivation of values for ..gamma.., proportional to N(0) (1 + lambda), is discussed, with strict attention given to limits of error. Particular note is taken of recent controversies concerning the correct values of ..gamma.. for A-15 V/sub 3/Si and Nb/sub 3/Sn. Using tunneling and infrared spectroscopy results for lambda where available, and an approximate phenomenological formula otherwise, values for the electronic de… more
Date: January 1, 1982
Creator: Stewart, G.R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Concentration profile of hydrogen near the surface of niobium

Description: Samples hydrided in two different ways were investigated. The materials used were thin foils (50 ..mu..m, MARZ grade) of niobium, 10 x 25 mm in size. The two methods of hydriding produced different surface conditions which were the subject of the present investigation. One method consisted of the following procedures. The samples were outgassed and cleaned in UHV to remove virtually all the interstitial impurities from the bulk and surface. A small spot of Pd was then deposited onto the clean s… more
Date: January 1, 1982
Creator: Pick, M. A.; Hanson, A.; Jones, K. W. & Goland, A. N.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Ferroelectric ceramics for dielectric power conversion. Annual report, March 1, 1979-April 30, 1980

Description: Materials selected for study were those which could be expected to have useful Curie temperatures, resistivities, coercive fields, and Devonshire coefficients. Materials studied include PZT (lead-zirconia-titania system), Bi(Na,K)Ti/sub 2/O/sub 6/, rare earth titanoniobates, other tantalates and niobates, and thin films. Graphs are given for spontaneous polarization as a function of composition, temperature dependence of spontaneous polarization and coercive field for modified PSZT dielectrics,… more
Date: May 1, 1980
Creator: Payne, D. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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PROCESSING OF POWER REACTOR FUELS. Fifteenth Quarterly Progress Report, April 1-July 1, 1961

Description: The results of experiments in support of an electrolytic dissolution process for fuel elements clad in stainiess steel or zirconium are given. The rate of disintegration of Zircaloy-2 anodes in nitric acid did not vary with acid concentration. Nitric oxide, formaldehyde, and process solvent were found effective in reducing the corrosion of stainiess steel equipment that was caused by the chromate present in acid solutions containing d ssolved stainless steel. Means were developed to improve the… more
Date: September 1, 1961
Creator: Owen, J.H. comp.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Extraction of Niobium-95 From Nitric Acid Solutions With Tri-N-Butyl Phosphate

Description: The distribution coefficient (DC o/a) of Nb/sup 95/ between aqueous nitric acid and 30% Tri-n-butyl phosphate (TBP) in n-dodecane increased from ~0.004 to O.1 N acid deficient solution to 0.05 in 4 M HNO/sub 3/ for the extractable portion of the niobium. Greater than 70% of the niobium was unextractable. The presence of 3% chemically degraded TBP, 7% chemically degraded Amsco, or both decreased the amount of unextractable niobium to <20% and degraded TBP increased the distribution of the extrac… more
Date: July 1, 1962
Creator: Moore, J. G. & Rainey, R. H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Stimulated Raman scattering at kHz-pulse-repetition rates. Quarterly report, 10 August 1976-10 November 1976. [LiIO/sub 3/ and LiNBO/sub 3/]

Description: Experiments have been carried out on the two-mirror configuration of a LiIO/sub 3/ Raman oscillator. With the two-mirror setup, 1.0 watt average power was obtained in the 1.18 ..mu..m 1st Stokes line and 550 mW in the 1.31 ..mu..m 2nd Stokes line. Both of these represent new records for SRS. The two-mirror configuration has very stable outputs and is probably superior to the three-mirror configuration for most applications. In addition, mode-locked operation of the two-mirror Raman oscillator h… more
Date: January 1, 1976
Creator: Ammann, E.O.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Ethanol synthesis and water gas shift over bifunctional sulfide catalysts

Description: The objective of the proposed research is to investigate and develop a novel catalytic process for the conversion of coal-derived synthesis gas into high octane C{sub 1}-C{sub 4} alcohols, especially ethanol, by a highly selective and efficient pathway. (VC)
Date: March 1, 1992
Creator: Klier, Kamil & Herman, Richard G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Neutron scattering studies of alkali metal--graphite intercalation compounds

Description: Elastic and inelastic neutron scattering are reported for C/sub 8/Rb in the temperature range 4 to 800 K. Several phase transitions above room temperature are reported for the first time; these consist of changes in metal layer stacking and ultimately at 747 K the onset of 2D liquid behavior. Phonon dispersion of LA and LO modes propagating along c imply a 20% increase in the interlayer force constant relative to pure graphite. The zone boundary TA mode softens dramatically with increasing temp… more
Date: January 1, 1977
Creator: Ellenson, W.D.; Semmingsen, D. & Fischer, J.E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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High-temperature electrically conductive ceramic composite and method for making same

Description: The present invention relates to a metal-oxide ceramic composition useful in induction heating applications for treating uranium and uranium alloys. The ceramic composition is electrically conductive at room temperature and is nonreactive with molten uranium. The composition is prepared from a particulate admixture of 20 to 50 vol. % niobium and zirconium oxide which may be stabilized with an addition of a further oxide such as magnesium oxide, calcium oxide, or yttria. The composition is prepa… more
Date: June 9, 1981
Creator: Beck, D.E.; Gooch, J.G.; Holcombe, C.E. Jr. & Masters, D.R.
Item Type: Refine your search to only Patent
Partner: UNT Libraries Government Documents Department
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Relative radiation sensitivity of insulators, stabilizers, and superconductors

Description: The objective of this work was to compare the radiation sensitivity of the various parts of superconducting magnet systems. Using the radiation spectra calculated by Engholm for the Engineering Test Facility (ETF) toroidal field magnet inboard leg and available data on radiation effects, commonly used magnet components were ranked in order of radiation sensitivity. It was found that epoxy-based insulators and copper and aluminum stabilizers were the most sensitive parts of the magnets, more sen… more
Date: January 15, 1982
Creator: Van Konynenburg, R.A. & Guinan, M.W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Potential applications of NbN composites in fusion reactor magnets

Description: Recent projected requirements for large scale fusion reactor magnets call for the development of advanced superconducting materials capable of producing peak magnetic fields in excess of 15 T with current densities in the windings in excess of 2 x 10/sup 3/ A/cm/sup 2/. These materials will be exposed to large stresses (up to 500 MPa) and neutron fluences as high as 10/sup 22/ n/cm/sup 2/ over the lifetime of the conductor. The demonstrated strain and radiation tolerance of NbN together with ex… more
Date: February 1, 1986
Creator: Capone, D. W., II; Gray, K. E.; Kampwirth, R. T. & Ho, H. L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Ion implantation and laser annealing of high T/sub c/ superconducting materials

Description: The materials investigated consisted of thin films of Nb-Ge, V-Si, Nb-N, Nb-C-N and Nb-Ir prepared by evaporation, sputtering or CVD onto substrates of alumina, sapphire or polycrystalline Hastelloy B. Single crystals of Nb/sub 3/Ir, NbN, V/sub 3/Si and V/sub 3/Ge were also studied and some laser annealing results will be presented. Laser annealing was performed in air using a Q-switched, (15 x 10/sup -9/ sec duration), Ruby laser with energy densities ranging from 0.1 to 10 J/cm/sup 2/. Single… more
Date: December 1, 1979
Creator: Appleton, B. R.; White, C. W.; Stritzker, B.; Meyer, O.; Gavaler, J. R.; Braginski, A. I. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Contributions to the INTOR workshop

Description: This paper discusses the use of Nb/sub 3/Sn conductors as coils for toroidal fields in thermonuclear reactors. In particular, the mechanical properties are investigated for these conductors as well as substitute materials. 8 refs.
Date: December 9, 1987
Creator: Miller, J.R. (comp.)
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Optics and materials research for controlled radiant energy transfer in energy efficient buildings

Description: During the past year important progress has been made in regard to uncovering and solving several key problems with respect to developing a lithium-based, monolithic, completely inorganic, reflectivity-modulating, robust electronic window to the point where its technology transfer can be smoothly accomplished. The major problems remaining to be solved are: (a) develop a counterelectrode layer which, as part of the multilayer window structure, is optically and electrochemically satisfactory; (b)… more
Date: January 1, 1990
Creator: Goldner, R.B. & Haas, T.E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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RF superconducting properties of thin films on niobium

Description: We are investigating the RF properties of thin films of materials which are known to have low secondary emission coefficients, such as NbC, NbN and TiN. Preliminary measurements on the latter material have been performed by depositing a 15 nm film on parts of a doubly re-entrant Nb cavity designed to favor electron multipacting which, in the uncoated cavity, occurs copiously between the posts' tips. The measurements performed with TiN films sputtered onto Nb indicate that the RF current losses … more
Date: March 1, 1983
Creator: Campisi, I. E.; Deruyter, H.; Farkas, Z. D.; Garwin, E. L.; Hogg, H. A.; King, F. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Spectroelectrochemistry in melts: applications to molten chloroaluminates

Description: Spectroelectrochemistry is an effective approach to studies of redox chemistry in solutions. uv-visible spectroelectrochemical studies in molten chloroaluminates (AlCl/sub 3/--NaCl mixtures) were initiated using a silicon vidicon rapid-scan spectrometer. Electrodes made from glassy carbon foam and metal grids are used in optically transparent thin layer cells. The solute species of interest are the oxidation products of sulfur and some of the Group IVB--VIB transition metal ions. The apparatus … more
Date: January 1, 1978
Creator: Mamantov, G.; Norvell, V. E. & Klatt, L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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9. 1-T iron-free Nb-Ti dipole magnet with pancake windings

Description: An eight-pancake Nb-Ti dipole magnet, with bent up ends, called D-108B has been built and tested. This magnet is a Nb-Ti version of a Nb/sub 3/Sn magnet designed to produce a 10-tesla dipole field in a 40 mm diameter aperture. The pancack design is used for the heavy 12,000 ampere Nb/sub 3/Sn cable because of the mechanical difficulty in winding such a heavy cable into the conventional nested cylindrical shell configuration with a 2'' inner winding diameter. The Nb-Ti version operates at 1.8K, … more
Date: March 1, 1983
Creator: Gilbert, W.; Caspi, S.; Hassenzahl, W.; Meuser, R.; Peters, C.; Rechen, J. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Response of ferroelectric ceramics to uniaxial stress. [Nb doped PZT 95/5]

Description: Changes in electrical polarization of ferroelectric ceramics subjected to non-hydrostatic stress can be caused by rotation of ferroelectric domains, or, in the case of materials near ferroelectric to antiferroelectric phase boundaries, by a stress-induced phase transformation. Both processes have been observed in mechanical measurements on PZT 95/5. The results may have important implications for the operation of shock-actuated ferroelectric power supplies.
Date: January 1, 1979
Creator: Fritz, I.J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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