12,649 Matching Results

Search Results

Advanced search parameters have been applied.

Tuballoy Oxides in the Reduction of TO₃

Description: Introduction: "This investigation was undertaken because of the importance of the reduction of TO3 to TO2 by hydrogen gas in the conversion of TO3 to TF4. We hoped to discover what factors affect the rate of reduction and the quantitativeness of the yield."
Date: 1945
Creator: Tanford, Charles; Tichenor, R. L. & Larson, C. E.
Partner: UNT Libraries Government Documents Department

Contributions to the Data on Theoretical Metallurgy: [Part] 12. Heats and Free Energies of Formation of Inorganic Oxides

Description: From Introduction: "This bulletin purposes to collect and compile, in readily usable form, heat and free-energy-of-formation data for inorganic oxides. Such data are used in evaluating heat balances in metallurgical processes, in appraising possible improvements in existing metal extractive methods, and as a guide in the search for better methods of producing metals of recent or possible future commercial interest."
Date: 1954
Creator: Coughlin, James P.
Partner: UNT Libraries Government Documents Department

Oxides in Pig Iron: Their Origin and Action in the Steel-Making Process

Description: From Introduction: "In summarizing the evidence in the literature it is apparent that there is general agreement among furnace men on the existence of so-called "bad-iron." It is also evident that the existence of dissolved or occluded gases is not an explanation. The presence of suspended oxides has been proved, and at least one plausible explanation for their formation has been given."
Date: 1929
Creator: Herty, C. H., Jr. & Gaines, J. M., Jr.
Partner: UNT Libraries Government Documents Department

Creep in electronic ceramics

Description: High-temperature creep measurements combined with microstructural investigations can be used to elucidate deformation mechanisms that can be related to the diffusion kinetics and defect chemistry of the minority species. This paper will review the theoretical basis for this correlation and illustrate it with examples from some important electronic ceramics having a perovskite structure. Recent results on BaTiO{sub 3}, (La{sub 1{minus}x}Sr){sub 1{minus}y}MnO{sub 3+{delta}}, YBa{sub 2}Cu{sub 3}O{sub x}, Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub x}, (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} and Sr(Fe,Co){sub 1.5}O{sub x} will be presented.
Date: April 27, 2000
Creator: Routbort, J. L.; Goretta, K. C. & Arellano-Lopez, A. R.
Partner: UNT Libraries Government Documents Department

Phase formation and superconductivity in PIT-type (Bi,Pb)-1212

Description: It was shown via powder-in-tube (PIT) processing that the (Bi,Pb)-1212 phase readily forms inside a silver sheath at 920 C in air. Composition, oxygen pressure, time, and temperature were all varied to study their effects on (Bi,Pb)-1212 phase purity and superconductivity.
Date: January 13, 2000
Creator: Murphy, N. M.; Dorris, S. E.; Miller, D. J.; Luo, Z. P.; Claus, H. & Maroni, V. A.
Partner: UNT Libraries Government Documents Department

Experimental Evidence for Topological Doping in the Cuprates

Description: Some recent experiments that provide support for the concept of topological doping in cuprate superconductors are discussed. Consistent with the idea of charge segregation, it is argued that the scattering associated with the ''resonance'' peak found in YBa{sub 2}Cu{sub 3}O{sub 6+x} and Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} comes from the Cu spins and not from the doped holes.
Date: April 6, 1999
Creator: Tranquada, J. M.
Partner: UNT Libraries Government Documents Department

Phase relationships and cation disorder in RE{sub 1+x}Ba{sub 2-x}Cu{sub 3}O{sub 7+{delta}}, RE = Pr, Nd, Sm, Gd

Description: Unlike Y123 which forms only a stoichiometric compound, the light arare earth elements (LRE) form a solid solution LRE{sub 1+x}Ba{sub 2-x}Cu{sub 3}O{sub 7+{delta}} (LRE123ss), with increasing substitution of the LRE{sup 3+} for the Ba{sup 2+} as the ionic radii of the LRE increases. The sub-solidus phase relationships around the LRE123ss change for La, Pr and Nd, but are similar for Sm and Gd. However, the solubility limit decreases with decreasing ionic radii. In addition, the solubility limits for Sm and Gd are strongly influenced by PO{sub 2} during high temperature annealing. The range of solubility is, for any given LRE system, strongly dependent on the oxygen partial pressure (PO{sub 2}) providing a new means by which to control the microstructure in the RE123 system.
Date: December 31, 1995
Creator: Kramer, M.J.; Wu, H.; Dennis, K.W.; Polzin, B.I.; Falzgraf, D.K. & McCallum, R.W.
Partner: UNT Libraries Government Documents Department

Magnetic and Charge Fluctuations in High-T(Sub c) Superconductors

Description: Neutron scattering has been used to study the spin fluctuations in the YBaCuO and BiSrCaCuO materials. Evidence is found for both incommensurate fluctuations and a commensurate resonance excitation. Measurements on the lattice dynamics for YBaCuO show incommensurate structure that appears to stem from charge fluctuations that are associated with the spin fluctuations.
Date: June 2, 1998
Creator: Chakoumakos, B.C.; Dogan, F. & Mook, H.A.
Partner: UNT Libraries Government Documents Department

Pressure as a probe of the physics of relaxor ferroelectrics

Description: Pressure studies have provided new insights into the physics of compositionally-disordered ABO{sub 3} oxide relaxors. Specifically, results will be presented and discussed on a pressure-induced ferroelectric-to-relaxer crossover phenomenon, the continuous evolution of the energetic and dynamics of the relaxation process, and the interplay between pressure and electric field in determining the dielectric response.
Date: January 25, 2000
Creator: SAMARA,GEORGE A.
Partner: UNT Libraries Government Documents Department

Uniformly Reactive Uranium Dioxide from a Single Oxidation-Reduction Cycle

Description: Abstract: By use of a modified thermobalance and reactor as the primary experimental tool for sample preparation and evaluation, a process has been developed by which parent uranium feed materials of a widely variable reactivity and composition may be converted to a uniformly reactive uranium dioxide.
Date: August 28, 1963
Creator: Orrick, N. C.; Jones, C. G.; Hale, C. F.; Barber, E. J. & Rapp, Karl E.
Partner: UNT Libraries Government Documents Department

CERIUM AND PLUTONIUM DIOXIDE--NOTES ON REDUCTION TO MASSIVE METAL

Description: In reduction reactions of CeO/sub 2/, with calcium and a CaCl/sub 2/ flux, the use of vibrational energy was shown to have a marked effect on the yield of coalesced metal. Buttons of 40 to 50% theoretical yield were obtained from the vibrated reductions. As the flux concentration is decreased, the slag becomes more viscous containing undissolved CaO. The undissolved CaO present prevents the metal from completely coalescing, but the metal can be recovered from the slag and coalesced under CaCl/sub 2/ containing a small amount of calcium to reduce any oxide skin present. Cerium pellet yields of 50 to 60% metal were obtained by the procedure and were not difficult to handle in air. Cerium was used as a stand-in material for plutonium. (B.O.G.)
Date: February 13, 1956
Creator: Tolley, W. B.
Partner: UNT Libraries Government Documents Department

Electronic contribution to friction on GaAs

Description: The electronic contribution to friction at semiconductor surfaces was investigated by using a Pt-coated tip with 50nm radius in an atomic force microscope sliding against an n-type GaAs(100) substrate. The GaAs surface was covered by an approximately 1 nm thick oxide layer. Charge accumulation or depletion was induced by the application of forward or reverse bias voltages. We observed a substantial increase in friction force in accumulation (forward bias) with respect to depletion (reverse bias). We propose a model based on the force exerted by the trapped charges that quantitatively explains the experimental observations of excess friction.
Date: April 15, 2008
Creator: Applied Science and Technology Graduate Group, UC Berkeley; Dept. of Materials Sciences and Engineering, UC Berkeley; Salmeron, Miquel; Qi, Yabing; Park, J.Y.; Hendriksen, B.L.M. et al.
Partner: UNT Libraries Government Documents Department

Ceramic Investigations of UO₂

Description: This report covers the progress made on an intensive program to develop and evaluate UO2 as a possible fuel element for the PWR.
Date: June 16, 1955
Creator: Allison, Adrian G. & Duckworth, Winston Howard, 1918-
Partner: UNT Libraries Government Documents Department

A{sub 2}Zn{sub 3}As{sub 2}O{sub 2}(A = Ba, Sr): a rare example of square planar zinc

Description: Purpose of this study was to explore synthesis of novel solid-state compounds that could potentially exhibit interesting or useful physical properties. Goal was to extend the classes of compounds A{sub 2}Mn{sub 3}Pn{sub 2}O{sub 2} (A=Sr,Ba; Pn=P,As,Sb,Bi) to include a transition metal other than Mn. High-temperature fluxes were used to produce these new compounds.
Date: June 1994
Creator: Keane, P. M. & Burdett, J. K.
Partner: UNT Libraries Government Documents Department