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Hot gas desulfurization with oxides of zinc, iron, and vanadium

Description: The objective of this study is to develop an improved sorbent which can reduce H{sub 2}S levels up to 1 ppmv or less, which can stabilize zinc, and produce economically recoverable amounts of elemental sulfur during regeneration. For this purpose, the desulfurization performance of sorbents prepared by the addition of various amounts of V{sub 2}O{sub 5} to the zinc ferrite sorbent is investigated.
Date: January 1, 1992
Creator: Akyurtlu, J.F. & Akyurtlu, A.
Partner: UNT Libraries Government Documents Department
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First principles energetic calculations of sapphire (0001) and (1 1 02) surfaces

Description: Various crystallographic faces of sapphire, the undoped single crystal {alpha}-Al{sub 2}O{sub 3}, have been widely used as substrates fro depositing thin films of metals, semiconductors, and insulators for basic scientific studies and for microelectronic applications. Epitaxial TiO{sub 2} and VO{sub 2} thin films were successfully grown on (0001), (1102) and (1120) surfaces of sapphire substrates by the Metal Organic Chemical Vapor Deposition (MOCVD) technique in our experimental program. The p… more
Date: March 1, 1992
Creator: Guo, J.; Ellis, D.E. & Lam, D.J.
Partner: UNT Libraries Government Documents Department
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Large-area non-crystalline semiconductor detectors

Description: The properties of various non-crystalline semiconductors are considered for use as position-sensitive detectors. Amorphous silicon and conducting plastic can be doped to form NP depletion regions similar to those in single crystal silicon, but without the limitation of single-crystal size. Chalcogenide glassy materials such as Te-Se-Ge compounds as well as some metallic oxides such as the Vanadium oxides have switching and memory properties. They could serve as x,y location identifying devices … more
Date: March 1, 1983
Creator: Perez-Mendez, V.; Mulera, T.; Kaplan, S. N. & Wiedenbeck, P.
Partner: UNT Libraries Government Documents Department
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Design and evaluation of progressively burning pyrotechnic formulations

Description: The design and evaluation of a pyrotechnic that burns for 2 ms and generates gas cubically with time is described. The charge is a mixture of two aluminum-plated pyrotechnics, viz., aluminum-potassium perchlorate (Al-KCl0/sub 4/) and aluminum-vanadium pentoxide (Al-V/sub 2/O/sub 5/). The Al-KCl0/sub 4/ is a gas generator, each gram of which produces 320 cc of gas (STP); the Al-V/sub 2/O/sub 5/, on the other hand, is a gasless pyrotechnic. Progressive generation of gas is achieved by utilizing m… more
Date: January 1, 1980
Creator: Austing, J. L. & Cooper, P. W.
Partner: UNT Libraries Government Documents Department
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Structural refinement of neutron and x-ray data by the Rietveld method: application to Al/sub 2/O/sub 3/ and BiVO/sub 4/

Description: The application of the Rietveld refinement technique to neutron and x-ray powder data from standard samples of Al/sub 2/O/sub 3/ is described. The results are compared with those obtained by conventional refinements of the corresponding integrated intensities, and also with x-ray single crystal data. The Rietveld technique has also been used to analyze neutron and x-ray powder data in a structural study of BiVO/sub 4/. Since V has a very small neutron scattering amplitude, the x-ray data allow … more
Date: January 1, 1979
Creator: Cox, D. E.; Moodenbaugh, A. R.; Sleight, A. W. & Chen, H. Y.
Partner: UNT Libraries Government Documents Department
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The finite size effect on the metal-insulator transition of MOCVD grown VO sub 2 films

Description: We studied the finite size effect on the metal-insulator phase transition and the accompanying tetragonal to monoclinic structural phase transition of VO{sub 2} films grown by MOCVD. X-ray diffraction measurements and electrical conductivity measurements were done as a function of temperature for VO{sub 2} films with out-of-plane particle size ranging from 60--310 {Angstrom}. Each Vo{sub 2} film was grown on a thin TiO{sub 2} buffer layer, which in turn was grown by MOCVD on a polished sapphire… more
Date: November 1, 1991
Creator: Kim, Hyung Kook; Chiarello, R.P.; You, Hoydoo; Chang, M.H.L.; Zhang, T.J. & Lam, D.J.
Partner: UNT Libraries Government Documents Department
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R-curve behavior in ferrite ceramics

Description: The unusual dependence of the fracture mode of ferrite ceramics on the stress intensity factor in the subcritical crack growth regime was used to create flaws with different concentrations of crack-interface bridges. Flaws with numerous bridges were produced by indenting under dry silicone oil, while flaws with essentially no bridges were produced by indenting under water. Plots of log failure stress as a function of log indenter load for the two types of flaws reflect the differences in bridgi… more
Date: January 1, 1990
Creator: Beauchamp, E. K. & Monroe, S. L.
Partner: UNT Libraries Government Documents Department
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Hot gas desulfurization with sorbents containing mixed metal oxides

Description: Advanced power generation systems such as the integrated gasification combined cycle power generators and the molten carbonate fuel cells have stringent fuel gas desulfurization requirements and process economics dictates that this desulfurization be performed near the temperature of the gasification off-gas. The most advanced hot gas desulfurization technology today is based on the zinc ferrite sorbent which has several shortcomings such as zinc loss by evaporation, and incomplete regeneration… more
Date: December 31, 1992
Creator: Akyurtlu, J. F. & Akyurtlu, A.
Partner: UNT Libraries Government Documents Department
open access

First principles energetic calculations of sapphire (0001) and (1{bar 1}02) surfaces

Description: Various crystallographic faces of sapphire, the undoped single crystal {alpha}-Al{sub 2}O{sub 3}, have been widely used as substrates fro depositing thin films of metals, semiconductors, and insulators for basic scientific studies and for microelectronic applications. Epitaxial TiO{sub 2} and VO{sub 2} thin films were successfully grown on (0001), (1102) and (1120) surfaces of sapphire substrates by the Metal Organic Chemical Vapor Deposition (MOCVD) technique in our experimental program. The p… more
Date: March 1, 1992
Creator: Guo, J.; Ellis, D. E. & Lam, D. J.
Partner: UNT Libraries Government Documents Department
open access

Hot gas desulfurization with oxides of zinc, iron, and vanadium

Description: The objective of this study is to develop an improved sorbent which can reduce H{sub 2}S levels up to 1 ppmv or less, which can stabilize zinc, and produce economically recoverable amounts of elemental sulfur during regeneration. For this purpose, the desulfurization performance of sorbents prepared by the addition of various amounts of V{sub 2}O{sub 5} to the zinc ferrite sorbent is investigated.
Date: August 1, 1992
Creator: Akyurtlu, J. F. & Akyurtlu, A.
Partner: UNT Libraries Government Documents Department
open access

Structure and property of heteroepitaxial TiO{sub 2}/VO{sub 2} multilayers

Description: Various types of TiO{sub 2}/VO{sub 2} multilayer structures have been prepared on sapphire substrates by a low-pressure metal-organic chemical vapor deposition process. X-ray diffraction and transmission electron microscopy techniques were used to study the crystallinity and epitaxial relationships of the deposited films. High resolution electron microscopy was used to examine the microstructure of the overlayers and interfaces. Electrical resistivity measurements were performed to investigate … more
Date: June 1, 1992
Creator: Chang, H. L. M.; Gao, Y.; Zhang, T. J. & Lam, D. J.
Partner: UNT Libraries Government Documents Department
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Optical and electrical experiments at some transition-metal oxide foil-electrolyte interfaces

Description: Metal-oxide layers formed from transition-metal foils oxidized by heating in air have been examined for their photoelectrolytic response. The metals examined are Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, and Pt. Weak photoeffects are observed for oxide layers of all of these metals. Sizable light-dependent oxygen gas evolution rates are found in Ti and also in W oxides. The spectral dependence of the oxygen response in these compounds is investigated, and interpretation is given of these experiments.
Date: 1977~
Creator: Sari, S. O. & Ahlgren, W. L.
Partner: UNT Libraries Government Documents Department
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Neutron scattering studies of the structural phase transformation in NbO/sub 2/

Description: NbO/sub 2/ shows an apparently second order phase transformation at T/sub c/ approximately equal to 810/sup 0/C, which coincides with anomalous changes in both electrical and magnetic properties. New neutron scattering measurements are summarized and the nature of the structural distortions and the relation between the structural instabilities in the isoelectronic compounds VO/sub 2/ and NbO/sub 2/ are discussed.
Date: January 1, 1975
Creator: Axe, J. D.; Pynn, R. & Thomas, R.
Partner: UNT Libraries Government Documents Department
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Structure and property of heteroepitaxial TiO sub 2 /VO sub 2 multilayers

Description: Various types of TiO{sub 2}/VO{sub 2} multilayer structures have been prepared on sapphire substrates by a low-pressure metal-organic chemical vapor deposition process. X-ray diffraction and transmission electron microscopy techniques were used to study the crystallinity and epitaxial relationships of the deposited films. High resolution electron microscopy was used to examine the microstructure of the overlayers and interfaces. Electrical resistivity measurements were performed to investigate … more
Date: June 1, 1992
Creator: Chang, H. L. M.; Gao, Y.; Zhang, T. J. & Lam, D. J.
Partner: UNT Libraries Government Documents Department
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Insulator to correlated metal transition in V_1-xMo_xO_2

Description: The change from metallic to insulating states is one of the most dramatic transitions that solids undergo on cooling or chemical doping. Many materials display this transition, but only a handful have the right combination of crystal structure and physical properties to serve as model systems. VO{sub 2} is one of those materials. Using Mo as a chemical dopant in VO{sub 2}, we find unanticipated phenomenology for both the electronic and structural characteristics of the resulting insulator to me… more
Date: January 1, 2009
Creator: Klimczuk, Tomasz; Ronning, Filip; Holman, Katherine; Mcqueen, Tyrel M; Williams, Anthony J; Stephens, P W et al.
Partner: UNT Libraries Government Documents Department
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Structure and electrochemical potential simulation for the cathode material Li(1+x)V(3)O(8).

Description: The structure and electrochemical potential of monoclinic Li{sub 1+x}V{sub 3}O{sub 8} were calculated within the local-density-functional-theory framework by use of plane-wave-pseudopotential methods. Special attention was given to the compositions 1+x=1.2 and 1+x=4, for which x-ray diffraction structure refinements are available. The calculated low-energy configuration for 1+x=4 is consistent with the three Li sites identified in x-ray diffraction measurements and predicts the position of the … more
Date: December 5, 1997
Creator: Benedek, R.; Thackeray, M. M. & Yang, L. H.
Partner: UNT Libraries Government Documents Department
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First-principles calculation of atomic structure and electrochemical potential of Li{sub 1+x}V{sub 3}O{sub 8}.

Description: Interest in the {gamma}-bronze, Li{sub 1+x}V{sub 3}O{sub g}, as a possible electrode material in rechargeable Li batteries has stimulated several experimental studies on this system. Detailed interpretation of the electrochemical and physical-property measurements is complicated by uncertainties regarding the structural arrangement of Li atoms as a function of x and by a phase transition between two monoclinic structures ({gamma}{sub a}, {gamma}{sub b}) during intercalation. To elucidate the at… more
Date: August 27, 1998
Creator: Benedek, R.
Partner: UNT Libraries Government Documents Department
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Optically Active Surfaces Formed by Ion Implantation and Thermal Treatment

Description: Embedded VO{sub 2} precipitates have been formed in single-crystal sapphire by the ion co-implantation of vanadium and oxygen and subsequent thermal annealing. The embedded VO{sub 2} particles have been shown to exhibit an optical switching behavior that is comparable to that of continuous thin films. In this work, the mechanisms of formation of these optically active particles are investigated. It is shown that precipitation of the vanadium dioxide phase is favored when the thermal treatment i… more
Date: August 1, 1996
Creator: Gea, L. A.; Boatner, L. A.; Evans, H. M. & Zuhr, R.
Partner: UNT Libraries Government Documents Department
open access

The finite size effect on the metal-insulator transition of MOCVD grown VO{sub 2} films

Description: We studied the finite size effect on the metal-insulator phase transition and the accompanying tetragonal to monoclinic structural phase transition of VO{sub 2} films grown by MOCVD. X-ray diffraction measurements and electrical conductivity measurements were done as a function of temperature for VO{sub 2} films with out-of-plane particle size ranging from 60--310 {Angstrom}. Each Vo{sub 2} film was grown on a thin TiO{sub 2} buffer layer, which in turn was grown by MOCVD on a polished sapphire… more
Date: November 1, 1991
Creator: Kim, Hyung Kook; Chiarello, R. P.; You, Hoydoo; Chang, M. H. L.; Zhang, T. J. & Lam, D. J.
Partner: UNT Libraries Government Documents Department
open access

Superconductivity, magnetism and metal-insulator transitions in some ternary and pseudoternary 3d-, 4d- and 5d-metal oxides

Description: Electron conduction effects have been found to be particularly important in the metallic compounds LiV{sub 2}O{sub 4} and possibly Sr{sub 2}Ir{sub 1-x}Ru{sub x}O{sub 4} (x > 0.7), but not in metallic Sr{sub 1-x}La{sub x}VO{sub 3} (x < 0.7), and they cause the compounds Sr{sub 2}IrO{sub 4} and ZnV{sub 2}O{sub 4} to be (Mott-Hubbard) insulators. The LiV{sub 2}O{sub 4} spinel compound is especially interesting, because the V ions exhibit rather clear local moment (S = 1/2) behavior even though the… more
Date: December 31, 1994
Creator: Johnston, D. C.; Borsa, F.; Kim, K. H.; Manajan, A. V.; Miller, L. L.; Torgeson, D. R. et al.
Partner: UNT Libraries Government Documents Department
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Rechargeable thin-film lithium batteries

Description: Rechargeable thin-film batteries consisting of lithium metal anodes, an amorphous inorganic electrolyte, and cathodes of lithium intercalation compounds have been fabricated and characterized. These include Li-TiS{sub 2}, Li-V{sub 2}O{sub 5}, and Li-Li{sub x}Mn{sub 2}O{sub 4} cells with open circuit voltages at full charge of about 2.5 V, 3.7 V, and 4.2 V, respectively. The realization of these robust cells, which can be cycled thousands of times, was possible because of the stability of the am… more
Date: September 1, 1993
Creator: Bates, J. B.; Gruzalski, G. R.; Dudney, N. J.; Luck, C. F. & Yu, X.
Partner: UNT Libraries Government Documents Department
open access

Thin-film rechargeable lithium batteries

Description: Rechargeable thin-films batteries with lithium metal anodes, an amorphous inorganic electrolyte, and cathodes of lithium intercalation compounds have been fabricated and characterized. The cathodes include TiS{sub 2}, the {omega} phase of V{sub 2}O{sub 5}, and the cubic spinel Li{sub x}Mn{sub 2}O{sub 4} with open circuit voltages at full charge of about 2.5 V, 3.7 V, and 4.2 V, respectively. The development of these robust cells, which can be cycled thousands of times, was possible because of t… more
Date: November 1, 1993
Creator: Bates, J. B.; Gruzalski, G. R.; Dudney, N. J.; Luck, C. F. & Yu, X.
Partner: UNT Libraries Government Documents Department
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Sol-gel deposited electrochromic coatings

Description: Electrochromic devices have increasing application in display devices, switchable mirrors and smart windows. A variety of vacuum deposition technologies have been used to make electrochromic devices. The sol- gel process offers an alternative approach to the synthesis of optical quality and low cost electrochromic device layers. This study summarizes the developments in sol-gel deposited electrochromic films. The sol-gel process involves the formation of oxide networks upon hydrolysis-condensat… more
Date: June 1, 1995
Creator: Ozer, N. & Lampert, C.M.
Partner: UNT Libraries Government Documents Department
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Optical indices of lithiated electrochromic oxides

Description: Optical indices have been determined for thin films of several electrochromic oxide materials. One of the most important materials in electrochromic devices, WO{sub 3}, was thoroughly characterized for a range of electrochromic states by sequential injection of Li ions. Another promising material, Li{sub 0.5}Ni{sub 0.5}O, was also studied in detail. Less detailed results are presented for three other common lithium-intercalating electrochromic electrode materials: V{sub 2}O{sub 5}, LiCoO{sub 2}… more
Date: September 1, 1996
Creator: Rubin, M.; Rottkay, K. von; Wen, S.J.; Ozer, N. & Slack, J.
Partner: UNT Libraries Government Documents Department
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