Materials Literature
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Thermopower and electrical conductivity studies of copper substituted Mg-Al ferrites are undertaken over the temperature range 300 to 700 K. On the basis of the sign of the Seebeck coefficient (S), the ferrites under study can be considered as n-type semiconductors. A model is arrived at using Seebeck coefficient data…
The transport properties of undoped and copper-doped indium oxide and indium tin oxide ceramics are investigated. The correlation between density, carrier concentration, and mobility is analysed. The density of IO ceramics can be considerably increased by copper doping and approaches that of single crystals for 5 mol%…
The report covers the following themes: SOFC chemistry, properties of SOFC gases and materials, electrochemistry, electric current flow in SOFC elements, SOFC configurations, mass flow phenomena and linearized SOFC performance analysis. figs., tabs., 27 refs.
Abstract The pyrolysis kinetics of highly crosslinked polymethylsiloxane (PMS) was investigated by thermogravimetric analysis (TGA) under both isothermal and elevated temperature conditions with several environmental gases, such as oxygen, nitrogen, air, and helium. A non‐chain‐scission mechanism composed of initiatio…
We report here selective deposition and fine-scale patterning of hot filament deposited diamond films by the use of pulsed laser irradiation on silicon and copper substrates. The substrates were abraded with diamond and alumina powders before hot-filament chemical vapor deposition. A drastic enhancement in diamond nuc…
We have performed an extensive theoretical investigation of amorphous phosphorus (a-P) using the molecular-dynamics--density-functional method. The energy surfaces and forces for 124 atoms in a constant-volume simple cubic cell were calculated using the density-functional formalism, with a local-density approximation…
We study the adsorption of grafted polymer layers on a planar surface parallel to the grafting surface. The layer consists of two types of chains: nonadsorbed chains with a free end and adsorbed chains forming bridges between the two plates. In the limit of strong adsorption a dead zone exists in the vicinity of the a…
Abstract Formulations containing 4 parts cornstrach, 5 parts poly(ethylene‐ co ‐acrylic) (EAA), 1 part urea, and 1.6 parts of either water or aqueous ammonia were extruded at either 110–120°C or 150–160°C; and the resulting extrudates were then extrusion‐blown into films. Complex formation between EAA and starch was m…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDetermination of pH with surface-enhanced Raman fiber optic probesKen I. Mullen, DaoXin. Wang, L. Gayle. Crane, and Keith T. CarronCite this: Anal. Chem. 1992, 64, 8, 930–936Publication Date (Print):April 15, 1992Publication History Published online1 May 2002Published inissu…
Abstract X‐ray diffraction, CP/MAS C‐13 NMR, DSC, FTIR and fluorescence microscopy have been used to study the structure, compatibility, and morphology of films made from starch, poly(ethylene‐ co ‐acrylic acid) (EAA), and polyethylene (PE) before and after exposure to a mixture of highly amylolytic bacteria. The comp…
Modification of the GaAs surface induced by the adsorption of Se atoms in a vacuum is studied by reflection high-energy electron diffraction (RHEED) and surface-sensitive photoemission spectroscopy. Se-induced variation of the surface structure is examined by RHEED for GaAs(001) surfaces with different surface composi…
Ks.sHI.5(SbW6024).6H20, Mr = 1933.48, trigonal, P3ml, a = 13.672 (3), c = 12.908 (5) A, V = 2089 (1)/~3, Z = 2, D,,, = 3.20, Dx = 3.07 g cm-3, A(Mo Ka) = 0.71069 A, # = 182.25 cm-~, F(000) = 1706, T = 298 K, final R = 0.060 and wR = 0.080 for 1089 independent reflections. The (5bW6024) 7- anion shows the Anderson-type…
A highly anisotropic Heisenberg spin one-half Hamiltonian is derived for the organometallic charge-transfer ferromagnet DMeFc-TCNE and its effective exchange parameters are estimated. Its relationship to the generally adopted McConnell picture of ferromagnetic interaction in such systems is established and particular…
The valence-band ultraviolet photoemission spectrum of ${\mathrm{VO}}_{2}$ has been studied above and below the semiconductor-metal phase-transition temperature (\ensuremath{\approxeq}340 K) as a function of exposure to hydrogen. Evidence is found for a partial reduction of the surface, leading to formation of adsorbe…
The role of resonance centers in obtaining large size matrices via an artificial intelligence (AI) search is discussed. The results are used to develop for an AI search an evaluation function which takes cognizance of isolated internal resonances in these many-state systems. The effect of later-accepted states on reso…
Abstract The isothermal crystallization from the melt of unreinforced poly(phenylene sulfide) (PPS) and of model carbon, aramid, and glass‐fiber‐reinforced PPS composites was studied by differential scanning calorimetry and optical microscopy. Crystallization was studied as a function of temperature, and the fiber con…
The rounding of the charge-density-wave depinning transition by thermal noise is examined. Hops by localized modes over small barriers trigger ``avalanches,'' resulting in a creep velocity much larger than that expected from comparing thermal energies with typical barriers. For a field equal to the T=0 depinning field…
An ab initio pseudopotential density-functional study of magnetic iron using both the standard local-spin-density approximation and a generalized gradient-expansion approximation is described. The core-valence overlap in this material is found to be important and is treated carefully in the calculation. A mixed-basis…
Quasiparticle excitation energies are calculated using the GW method for diamond under hydrostatic pressures up to 500 GPa and for one tetragonal configuration under an assumed additional stress in the [001] direction. The self-energy operator is approximated with a model for the static screened Coulomb interaction an…
Our previous work on time evolution of the interfacial structure for a near critical mixture of polybutadiene and polyisoprene undergoing the spinodal decomposition (SD) [T. Hashimoto, M. Takenaka, and H. Jinnai, J. Appl. Crystallogr. 24, 457 (1991)] was extended to explore the behavior as a function of temperature T,…