Materials Literature
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Phonon-dispersion curves for the hexagonal-layered compound Mo${\mathrm{S}}_{2}$ have been measured at room temperature by inelastic-neutron-scattering techniques for the [100] and [001] directions. The results have been analyzed on the basis of a model which includes valence forces between atoms in a layer and axiall…
A numerical charge integration procedure has been applied to diffraction data of TTF-TCNQ (tetrathiafulvalene-tetracyanoquinodimethane) measured at 100\ifmmode^\circ\else\textdegree\fi{}K. The results indicate an average charge transfer of (0.48-0.60) \ifmmode\pm\else\textpm\fi{} 0.15 electrons from a TTF to a TCNQ mo…
The thermoluminescence response to gamma rays of the most sensitive glow peaks in LiF (II to V) reaches a maximum and then decreases. The decrease in response is attributed to radiation damage. It is observed that even after the considerable reduction in the TL, which results from a heavy dose, the saturation exposure…
The electrical properties of La 1-x Sr x VO 3 change from those of a semiconductor to those of a metal as x is increased, with a metal-nonmetal transition occurring at x approximately=0.2. This has been studied using AC and DC conductivity and thermopower measurements over a temperature range from 4 to 400K. Evidence…
Coexisting metallic and semiconducting phases have been obtained by passing DC currents through VO 2 single crystals. The mixed state was studied by optical microscopy. Narrow semiconducting strips that nucleate at the positive edge of a metallic domain and propagate towards its negative edge have been observed under…
A ${T}^{2}$ behavior for the conductivity across the layers is observed in $4Hb$-Ta${\mathrm{S}}_{2}$ crystals below 35 K. This indicates that tunneling occurs between metallic layers separated by an insulating layer. Evidence for thermally activated hopping is observed at higher temperatures.
The nematic-smectic-$A$ transition temperature of mixtures of HBAB {$p$-[($p$-hexyloxybenzylidene)-amino]benzonitrile} and CBOOA [N-$p$-cyanobenzylidene-$p\ensuremath{-}n$-octyloxyaniline] becomes multivalued with increasing concentration of HBAB. The nematic phase occurs at both a higher and a lower temperature than…
Abstract A modification of the concept of “seniority” for the classification of the permitted terms and the effective operators in complexes and molecules is presented. Tables of the states of complexes of impurity orbital nondegenerate ions ( N = 3, 4) with spin S ( \documentclass{article}\pagestyle{empty}\begin{docu…
A far-infrared bolometer detector using p-type thallium selenide (TlSe) single crystal as the temperature-sensitive element has been operated at 1.5 K with a noise-equivalent power (NEP) of 8.3 × 10−15 W/Hz1/2 and a response time constant of 8 × 10−3 s. The bolometer could be made faster without increasing NEP by redu…
Abstract Potassium hydrogen sulphate single crystal has been γ-irradiated at room temperature and its electron spin resonance spectrum recorded by changing the H 0 static magnetic field, around an orthogonal axes system. The electron spin resonance spectrum is a single line with a slightly anisotropic g factor. The pa…
A method has been developed to measure the related rotation of the flanges of a thin-walled tubular specimen during a torsion test. The method, which is based on the Moiré-fringe technique, is capable of use at the high rates of strain encountered during a Hopkinson-bar test, as well as at low rates of strain. In the…
Abstract Lactitol, prepared by reduction of lactose, was transesterified successfully with a series of fatty methyl esters with the aid of alkaline catalysts at 90 C. This was in marked contrast to previous experiences with lactose. Lactitol laurate, palmitate, stearate, and tallowate were prepared in this manner. The…
Most recently the practical importance of high temperature vaporization reactions has appeared in the synthesis of pure materials through vapor transport reactions and in the study of the movement of materials in nuclear power reactor experiments. The most recent basic development is the establishment, at temperature,…
Describes a solid state backscattered electron detector that has been developed at Harwell for use in a scanning electron microscope. Applications of the method of detection are discussed and examples of the three principal uses are shown. These are in the display of atomic number variations, examination of crystal qu…
Various combinations of biaxial stress were applied on five batches of recrystallized zircaloy-2 fuel cladding tubes with different textures; elongation in both axial and circumferential directions of the specimen was measured continuously up to 5% plastic deformation. The anisotropic theory of plasticity proposed by…
A new empirical method of averaging the shear modulus is proposed. The elastic Debye temperatures ϑ calculated for a number of cubic elements and semiconducting compounds have been found to be in excellent agreement with the corresponding computationally exact ϑ. The computed shear modulus is also in good agreement wi…
This article discusses primary and secondary particulates with respect to their size distribution, origin, and chemical composition. Primary particulates are particles that are injected directly into the atmosphere. Usually their sizes are within the range 1 to 20 jum. Common sources are windblown soil, industrial emi…
For various technological applications patterns are chemically etched in metal films partly covered with a nobler metal. As a result of the bimetallic contact, accelerated etching may occur, giving rise to considerable undercutting. From electrochemical considerations it was expected that the use of certain chemical p…
DEFORMATION MODES OF UNIDIRECTIONALLY SOLIDIFIED CARBIDE-REINFORCED COMPOSITES: IN SITU EXPERIMENTS IN THE HVEM RELATED TO MACROSCOPIC BEHAVIOUR In situ investigation of the plastic deformation in tension was performed in the high voltage electron microscope on a unidirectionally solidified metal matrix carbide-reinfo…
In this paper, the phenomenological effects of d→f and f→f processes are examined. The relationship between radiationless multiphonon decay and excitation processes is obtained in terms of the first-order adiabatic relaxation theory. A detailed analysis is given of the experimentally observed temperature dependence of…