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Full-Text Articles in Engineering
Q Dependence Of Self-Energy Effects Of The Plane Oxygen Vibration In Yba₂Cu₃O₇, Dmitry V. Reznik, Bernhard Keimer, Fatih Dogan, Ilhan A. Aksay
Q Dependence Of Self-Energy Effects Of The Plane Oxygen Vibration In Yba₂Cu₃O₇, Dmitry V. Reznik, Bernhard Keimer, Fatih Dogan, Ilhan A. Aksay
Materials Science and Engineering Faculty Research & Creative Works
We have measured the temperature dependence of the peak position and linewidth of the 42.5 meV phonon branch in a twinned single crystal of YBa2Cu3O7 as a function of wave vector q. In the 100/010 direction in the Brillouin zone, considerable softening and broadening occur below the superconducting transition temperature Tc at some values of q. We observe an order of magnitude smaller softening and no linewidth broadening for q in the 110/110 direction. Possible implications of these findings for the symmetry of the superconducting order parameter are discussed.
Phonon And Magnetic Neutron Scattering At 41 Mev In Yba₂Cu₃O₇, Hungfai Fong, Bernhard Keimer, Philip Warren Anderson, Dmitry V. Reznik, Fatih Dogan, Ilhan A. Aksay
Phonon And Magnetic Neutron Scattering At 41 Mev In Yba₂Cu₃O₇, Hungfai Fong, Bernhard Keimer, Philip Warren Anderson, Dmitry V. Reznik, Fatih Dogan, Ilhan A. Aksay
Materials Science and Engineering Faculty Research & Creative Works
We report inelastic neutron scattering measurements at excitation energies Latin small letter h with strokeω~41 meV in YBa2Cu3O7. We separate magnetic and phonon contributions to the scattering cross section by a detailed analysis of the momentum dependence of the scattered intensity. The previously reported broad peak around q=(π/a,π/a) in the normal state can be entirely accounted for by a phonon which primarily involves vibrations of the in-plane oxygen. Magnetic scattering centered around 41 meV and q=(π/a,π/a) appears in the superconducting state only. Theoretical implications of these findings are discussed.
Radiolabeled Protein Composition And Method For Radiation Synovectomy, D. E. Day, Gary J. Ehrhardt, Kurt R. Zinn
Radiolabeled Protein Composition And Method For Radiation Synovectomy, D. E. Day, Gary J. Ehrhardt, Kurt R. Zinn
Materials Science and Engineering Faculty Research & Creative Works
A radiolabeled protein composition adapted for radiation therapy which comprises a radioisotope and a protein material containing about 6 or more percent amino acids which have a sulfhydryl-containing side chain. A method for carrying out radiation synovectomy of arthritic joints. Rhenium radiolabeled protein micro- spheres are administered which contain cysteine and other amino acids. A method for radiolabeling a protein composition whereby the composition is treated with a reducing agent capable of reducing disulfides to sulfhydryls prior to radiolabeling.
High Temperature Interfacial Phenomena In Processing Cofired Ceramics For Electronic Packaging Of Semiconductor Devices, P. D. Ownby, D. A. Weirauch Jr., J. E. Lazaroff
High Temperature Interfacial Phenomena In Processing Cofired Ceramics For Electronic Packaging Of Semiconductor Devices, P. D. Ownby, D. A. Weirauch Jr., J. E. Lazaroff
Materials Science and Engineering Faculty Research & Creative Works
No abstract provided.
Immittance Response Of La0.6sr0.4co0.2fe0.8o3 Based Electrochemical Cells, C. C. Chen, M. M. Nasrallah, Harlan U. Anderson
Immittance Response Of La0.6sr0.4co0.2fe0.8o3 Based Electrochemical Cells, C. C. Chen, M. M. Nasrallah, Harlan U. Anderson
Materials Science and Engineering Faculty Research & Creative Works
The ac small-signal response of La0.6Sr0.4CO02Feo.803 (LSCF) is examined via lumped parameter/complex plane analysis (LP/CPA) technique. The ac data, acquired in the frequency range lO-1≤F≤106Hz, are used to establish the role of ionic contribution in the LSCF material system using a two-terminal blocking electrode method. Spun-on yttria (8 mole percent (m/o) Y203) stabilized zirconia (8YSZ) or Ce0.85Sm0.15O2 (CSO) thin film coatings (0.3 - 1.0 µm) is used as electron blocking electrodes. The temperature dependence of the contributing elements between the terminals, obtained via LP/CPA technique and dc measurements, is evaluated. The activation energy, associated with possible oxygen transport via an …
A Positron Annihilation Study Of Rotating Beam Fatigue Damage In The Superalloy Haynes 188, D. Hoeckelman, Hollis P. Leighly
A Positron Annihilation Study Of Rotating Beam Fatigue Damage In The Superalloy Haynes 188, D. Hoeckelman, Hollis P. Leighly
Materials Science and Engineering Faculty Research & Creative Works
No abstract provided.
Electrical And Thermal Transport Properties Of (La,Ca)(Cr,Co)O3, Rasit Koc, Harlan U. Anderson
Electrical And Thermal Transport Properties Of (La,Ca)(Cr,Co)O3, Rasit Koc, Harlan U. Anderson
Materials Science and Engineering Faculty Research & Creative Works
DC electrical conductivity and Seebeck data as functions of temperature and oxygen activity were used to explain the electrical and thermal transport properties of (La,Ca) (Cr,Co)O3. The electrical conductivity data of La (Cr,Co)O3 suggested that it depends upon Co content. At Co concentrations less than 20 mol%, Co acted as traps for the carriers and decreased the electrical conductivity of the compositions at temperatures less than 900 °C. As the Co concentration increased to above 20 mol%, electrical conductivity increased significantly due to a connecting path of available Co sites. Additional Ca substitution for La increased the electrical conductivity in …
Semiempirical Model For The Electrical Properties Of La1-Xcaxcoo3, S. R. Sehlin, Harlan U. Anderson, Don M. Sparlin
Semiempirical Model For The Electrical Properties Of La1-Xcaxcoo3, S. R. Sehlin, Harlan U. Anderson, Don M. Sparlin
Materials Science and Engineering Faculty Research & Creative Works
A semiempirical model of the Seebeck coefficient for a small polaron hopping conductor is presented. The population of small polarons is allowed to change as a function of temperature via the mechanism of charge disproportionation. The energy required for polaron formation by the disproportionation mechanism is modeled as screened by a Coulomb interaction with nearby small polarons. The charge carrier site occupancies generated by the model are used to successfully predict the electrical conductivity and Seebeck coefficient for compositions in the La1-xCaxCoO3 system. Cobalt ion valence populations predicted by the model are used to calculate effective paramagnetic moments for LaCoO3, …
Electrical Characterization Of The (La,Ca) (Cr,Co)O3 System, S. R. Sehlin, Harlan U. Anderson, Don M. Sparlin
Electrical Characterization Of The (La,Ca) (Cr,Co)O3 System, S. R. Sehlin, Harlan U. Anderson, Don M. Sparlin
Materials Science and Engineering Faculty Research & Creative Works
The results of electrical conductivity and thermopower measurements are presented for selected (La,Ca)(Cr,Co)O3 compositions. The La1 - xCaxCrO3 compounds are typical p-type small polaron conductors. The La1 - xCaxCrO3 compounds are found to be small polaron conductors at room temperature for x ≤ 0.20 with a higher electrical conductivity than the corresponding chromite's. The electrical conductivity at room temperature is lower for Co-rich compositions than for Cr-rich compositions for compositions containing 10 mol% and 20 mol% Ca. This fact is attributed to the trapping of p-type small polarons at energetically lower Cr sites, resulting in a broad room temperature conductivity …
Structure And Electrical Properties Of La1 - Xsrxco1 - Yfeyo3. Part 2. The System La1 - Xsrxco0.2fe0.8o3, L. W. Tai, M. M. Nasrallah, Harlan U. Anderson, Don M. Sparlin, S. R. Sehlin
Structure And Electrical Properties Of La1 - Xsrxco1 - Yfeyo3. Part 2. The System La1 - Xsrxco0.2fe0.8o3, L. W. Tai, M. M. Nasrallah, Harlan U. Anderson, Don M. Sparlin, S. R. Sehlin
Materials Science and Engineering Faculty Research & Creative Works
Crystal structure, thermal expansion, oxygen stoichiometry, thermoelectricity, and electrical conductivity of compositions in the system La1 - xSrxCo0.2Fe0.8O3 with 0 ≤ x ≤ 0.6 were studied as function of temperature and Sr content, in air. The solubility of Sr in the sintered perovskite-type oxide (ABO3) was limited to x ≤ 0.4. The observed p-type electrical conduction appeared to occur via a small-polaron hopping mechanism. The thermally induced oxygen loss caused a lattice expansion plus decreases in both the carrier concentration and the carrier mobility. A semi-empirical model was developed which takes into account the thermally activated disproportionation of Co3+ ions …
Structure And Electrical Properties Of La1-Xsrxco1-Yfeyo3. Part 1. The System La0.8sr0.2co1-Yfeyo3, L. W. Tai, M. M. Nasrallah, Harlan U. Anderson, Don M. Sparlin, S. R. Sehlin
Structure And Electrical Properties Of La1-Xsrxco1-Yfeyo3. Part 1. The System La0.8sr0.2co1-Yfeyo3, L. W. Tai, M. M. Nasrallah, Harlan U. Anderson, Don M. Sparlin, S. R. Sehlin
Materials Science and Engineering Faculty Research & Creative Works
Crystal structure, thermal expansion, thermogravimetry, thermoelectricity, and electrical conductivity of compositions in the system La0.8Sr0.2Co1-yFeyO3 with 0 ≤ y ≤ 1 were studied as function of Co Fe ratio and temperature, in air. The electrical conduction mechanism is attributed to the adiabatic-hopping of p-type small polarons. At high temperatures, oxygen deficiency causes lattice expansion and a reduction in electrical conductivity. The observed temperature dependence of the Seebeck coefficient is attributed to changes in carrier concentration caused by a thermally excited charge disproportionation of Co3+ ions and by the ionic compensation of induced oxygen vacancies. The measured electrical conductivity and Seebeck …
Anomalous-Diffusion Model Of Ionic Transport In Oxide Glasses, David L. Sidebottom, Peter F. Green, Richard K. Brow
Anomalous-Diffusion Model Of Ionic Transport In Oxide Glasses, David L. Sidebottom, Peter F. Green, Richard K. Brow
Materials Science and Engineering Faculty Research & Creative Works
The power-law frequency dependence of both the conductivity, (), and permittivity, (), of ion-conducting materials suggests that self-similar or scale-invariant behavior influences the transport of ions at high frequencies. Using an anomalous-diffusion model, we derive relevant power-law expressions for () and () and compare these with measurements performed on LiPO3 glass. Superior fits to the measured data are obtained compared to the commonly used Kohlrausch-Williams-Watts (KWW) description of the electrical modulus, most particularly in the notorious high-frequency regime. Evaluation of our results in terms of an anomalous-diffusion model suggests the dominance of interaction-based constraints to diffusion. © 1995 The American …
Two Contributions To The Ac Conductivity Of Alkali Oxide Glasses, David L. Sidebottom, Peter F. Green, Richard K. Brow
Two Contributions To The Ac Conductivity Of Alkali Oxide Glasses, David L. Sidebottom, Peter F. Green, Richard K. Brow
Materials Science and Engineering Faculty Research & Creative Works
Although the frequency dependent conductivity of ion-containing glasses often displays scale invariant power law dispersion at high temperatures, the exponent increases to unity at lower temperatures. We report measurements of the conductivity of a series of alkali metaphosphate glasses including a mixed alkali composition and demonstrate that this temperature dependence results from the superposition of two power law dispersions originating from separate mechanism, and does not indicate any intrinsic change in scaling of the process which dominates at high temperatures. © 1995 The American Physical Society.
Method Of Forming A Plasma Sprayed Interconnection Layer On An Electrode Of An Electrochemical Cell, Charles J. Spengler, George R. Folser, Shailesh D. Vora, Lewis Kuo, Von Richards
Method Of Forming A Plasma Sprayed Interconnection Layer On An Electrode Of An Electrochemical Cell, Charles J. Spengler, George R. Folser, Shailesh D. Vora, Lewis Kuo, Von Richards
Materials Science and Engineering Faculty Research & Creative Works
A dense, substantially gas-tight, electrically conductive interconnection layer is formed on an air electrode structure of an electrochemical cell by (A) providing an electrode surface; (B) forming on a selected portion of the electrode surface, a layer of doped LaCrO.sub.3 particles doped with an element selected from Ca, Sr, Ba, Mg, Co, Ni, Al and mixtures thereof by plasma spraying doped LaCrO.sub.3 powder, preferably compensated with chromium as Cr.sub.2 O.sub.3 and/or dopant element, preferably by plasma arc spraying; and, (C) heating the doped and compensated LaCrO.sub.3 layer to about 1100 to provide a dense, substantially gas-tight, substantially hydration-free, electrically conductive …