Materials Literature
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We present calculations of the frequency-dependent dielectric properties of semiconductors using the Penn model in the random-phase approximation, including collision effects via a phenomenological relaxation time $\ensuremath{\tau}$. Analytical expressions for ${\ensuremath{\epsilon}}_{1}(0,\ensuremath{\omega})$ (wit…
Subnanosecond photoconductive switching has been observed in ultraviolet illuminated type IIa diamonds. Switching efficiencies up to 50% were attainable in coaxially mounted samples for direct current bias voltage as high as 8 kV at room temperature.
A novel concept of ‘‘surface’’ spinodal decomposition is introduced in the context of wetting and prewetting first order transitions for simple fluids in contact with a bounding wall. Qualitative and semiquantitative discussions are made within the framework of a phenomenological Landau theoretical model for semi-infi…
Spectrally separated fluorescence emissions from liquid and vapor diesel fuel can be obtained by adding an exciplex-forming molecule to the fuel. The exciplex emission dominates the condensed phase emission, while the monomer emission dominates the vapor phase emission. In particular with the naphthalene/tetramethyl-p…
An all-metal facility has been built to handle about 1000 Ci of tritium for studies of the tritium behavior in metals. First measurements of the pressure-composition-temperature relationship for the palladium-tritium system $\mathrm{Pd}{\mathrm{T}}_{x}$ are reported for the pressure range $0.1\ensuremath{\le}p\ensurem…
The infrared and Raman spectra for the room temperature, quasineutral, and the low temperature, quasi-ionic, phases of the mixed stack charge transfer complex tetrathiafulvalene–chloranil (TTF–CA) are reported. The analysis of the analogous data for a newly synthesized room temperature phase point to a dimerized segre…
The structural parameters of the graphitic carbon overlayer on a Ni(111) substrate has been determined by using surface extended-energy-loss fine-structure spectroscopy. We find that graphitic carbon is very similar to a graphite single-crystal plane, but slightly expanded (\ensuremath{\sim}2%), with C-${\mathrm{C}}_{…
Bond-orientational order in molecular-dynamics simulations of supercooled liquids and in models of metallic glasses is studied. Quadratic and third-order invariants formed from bond spherical harmonics allow quantitative measures of cluster symmetries in these systems. A state with short-range translational order, but…
The breakdown mechanism for an inhomogeneous field geometry in SF 6 depends on the pressure and can be divided into a streamer dominated and a leader dominated region. Based on leader propagation criteria a model is given that qualitatively describes the pressure dependence of the breakdown voltage in inhomogeneous ga…
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Postirradiation examinations have been conducted as part of an extensive Babcock & Wilcox (B&W) program in reactor control materials performance characterization. These examinations of fixed burnable poison rods and control rods confirmed operational performance and extended the material behavior data base for irradia…
The wavefunction of the Fraunhofer diffraction from sector stars (i.e. radial gratings, spoke targets, Jewell's tests, Siemens' stars) is derived. Particular features of the diffraction patterns are explained by means of both the derived mathematical formulae and the general properties of Fraunhofer diffraction patter…
Abstract Der chemische Transport von GeO 2 mit H 2 nach Gl. (1) führt bei konstantem H 2 ‐Anfangsdruck (P°(H 2 ) = 1 atm) im Temperaturgradienten T 2 T 1 = 100 K zur Abscheidung eines feinkristallinen, farblosen Belages aus GeO 2 (hex.) bei T 1 , auf dem in Abhängigkeit von der mittleren Transporttemperatur T̄ nadel…
Abstract The polarization properties of the recombinative photoluminescence of free electrons excited to the conduction band of a cubic multivalley semiconductor by linearly and circularly polarized light are studied theoretically. The electron transitions from the valence band and impurities to the valleys of the con…
Polyamideimides (PAI) were prepared by the polycondensation reaction of the diacid chloride of N-(p-carboxy phenyl) trimellitimide and p, p′-di(amino phenyl) methane following three different techniques. The solution, thermal, chemical, and electrical properties of the polymer were studied. The polymer was found to be…
Abstract The description of electron density in solids by quantum theory and by x‐ray diffraction experiments should closely coincide. A formalism for describing the electronic structure of single crystals in terms of a density matrix is presented. Iterative equations for calculating the density matrix in a basis of B…
Orthorhombic α‐KFeSiO 4 ( a =0.5478, b =0.9192, c =0.8580 nm), hexagonal β‐KFeSiO 4 ( a =0.5309, c =0.8873 nm), and hexagonal γ‐KFeSiO 4 ( a =0.5319, c =0.8815 nm) were synthesized by devitrification of KFeSiO 4 glass. Powder X‐ray diffraction data are given for all three polymorphs. Alpha KFeSiO 4 , the high‐temperat…
Subsolidus equilibrium relations were reexamined in the SnO 2 ‐rich portion of the system GeO 2 ‐SnO 2 (60 to 98 mol% SnO 2 ). A limited solid solution based on SnO 2 was confirmed; 4mol% GeO 2 dissolved in SnO 2 at 1250 C, and glass was formed on quenching over the compositional range above 4mol% GeO 2 . Phase reluti…
Abstract not Available.
Abstract Three soil profiles containing two types of brittle horizons were extracted using citrate‐hicarbonate‐dithionite (CBD), a modified CBD, and NaOH procedures. The modified CBD method with a low soil‐solution ratio was the most effective extractant for Fe, Al, and, especially, Si. Increases in extractable Si cou…