Materials Literature
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A solution to the long-standing problem of the companion ${A}_{1}$ Raman line [symmetric breathing mode of Ge${(\mathrm{S},\mathrm{S}\mathrm{e})}_{4}$ tetrahedra] in Ge${(\mathrm{S},\mathrm{S}\mathrm{e})}_{2}$ glasses is proposed based on the observation of a similar doublet in the crystal. The proposed model assumes…
The electronic part of the dielectric constant epsilon infinity is calculated using a simple analytical model. The technique involves the use of the f sum rule to evaluate most of the detailed band structure information, and is closely related to the Penn model of an isotropic semiconductor in the use of this method,…
A simple model for the minimum obliquity required to induce ricochet of a high speed long rod projectile from a thick target plate is suggested.
Presents an account of recent studies on the structure of amorphous semiconductors, oxide and chalcogenide glasses and amorphous metals. Emphasis is placed on simple solids which are representative of each class of amorphous material and also on so-called direct structural techniques-for example, X-ray and neutron sca…
During the normal impact of a hard particle on a metal surface, some of the kinetic energy of the particle is radiated into the target as elastic waves. The amount of energy involved is calculated for impacts where the metal is deformed plastically, and is found to be typically only a few per cent of the initial kinet…
A theory for the memory function of the velocity autocorrelation function for a monatomic liquid is presented, based on a general kinetic approach. Strong emphasis is put on the coupling of the motion of a single particle to the collective motions in its surrounding, splitting the memory function into an essentially b…
Abstract An experimental study has been made of recrystallization processes which have been initiated at grain boundaries in aluminium samples. The samples had an initial grain size of between 30 and 130 μm and were deformed 50 % by rolling before annealing at 573 K. The microstructures developed in the region of the…
We have studied, using computer simulation techniques, the properties of edge and screw dislocations in an amorphous Lennard-Jones solid. We find the edge dislocation to be unstable and the screw to be stable. The elastic properties of the screw dislocation in the amorphous solid are like those in a crystal.
The habit of crystals grown from highly supersaturated solution has been formed to be governed by linkages of coordination polyhedra from a morphological analysis on the basis of crystal structure. Such a vector of linkages having a direction and an energetical period which represents the three dimensional structure m…
A discrete, calcareous layer that binds the foliated calcite of the oyster's shell to the organic ligament in the hinge is reported, apparently for the first time. This layer is ultrastructurally, and generally mineralogically, different from the underlying foliated calcite, and is named the ligostracum.
Abstract Small angle X‐ray scattering measurements were made on samples of polycarbonate (PC) and poly(methyl methacrylate) (PMMA) containing crazes. A sharp, well pronounced maximum in the scattering intensity was observed in the direction perpendicular to the draw direction. The distribution of scattered intensity a…
This Letter investigates the phonon scattering in Si${\mathrm{O}}_{2}$ glass at frequencies above 100 GHz by phonon spectroscopy with superconducting tunnel junctions. By analyzing the frequencies of the scattered phonons with two independent techniques, evidence is obtained for strong inelastic phonon scattering in g…
This Letter represents a theory of transport in random metal alloys which focuses on certain model-independent features of the electron-phonon dynamics which have been previously neglected. It is found that the adiabatic phonon approximation breaks down in the high-resistivity regime producing an anomalous negative te…
Article Verfeinerung der Kristallstruktur des Silberperchlorats AgClO4 was published on November 1, 1979 in the journal Zeitschrift für Kristallographie - Crystalline Materials (volume 149, issue 1-4).
It has long been known that thin films of cholesteric liquid crystals subject to a shear will exhibit a blue shift in the color that they reflect. In this article a molecular structure that could explain this shift is postulated. Using Mauguin’s continuum model of a cholesteric liquid crystal, the governing electromag…
Abstract Les spectres vibrationnels des phases Na 4 SnO 4 , Na 4 PbO 4 et K 4 SnO 4 ont été étudiés pour la première fois. Ils caractérisent des groupements tétraédriques XO 4 isolés. Les attributions des fréquences IR et Raman ont été effectuées par analyse du groupe facteur. Les constantes de forces, calculées à par…
Abstract Hot stretching experiments for an atactic polystyrene have been performed in the temperature range 125 to 180°C, at various elongation rates and with different times of application of the orienting field. Mechanical properties of the oriented samples, including Young's modulus, yield strain and stress, ultima…
The measurements of magnetostriction and anisotropy of r.f. sputtered amorphous Gd1−xCox thin films are reported. Both were measured in the range of composition x=0.667–0.835 using cantilever-capacitance method. The perpendicular anisotropy Ku and saturation magnetostriction λs reach extremal values in the vicinity of…
L-Fucose dehydrogenase [EC 1.1.1.122] was isolated from a rabbit liver extract and purified about 390-fold with a yield of approximately 13%. The purification procedures included treatment with protamine, ammonium sulfate fractionation, treatment with acid, DE-32 celluose colum chromatography, gel filtration on Sephad…
Abstract Tetrachlorothallates MTlCl 4 (M=K, Rb and NH 4 ) crystallizing in the tetragonal CaWO 4 type were obtained by crystallization from highly concentrated aqueous TlCl 3 solutions containing small amounts of MCI. The structural parameters of NH 4 TlCl 4 were determined from single-crystal data. The indates MInCL…