Materials Literature
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It is proposed that, during dislocation glide at low temperatures, both screw and non-screw dislocations annihilate mutually with dislocations of opposite sign approaching on closely neighbouring glide planes. The experimental evidence is summarized and possible mechanisms are discussed. Phenomenological models of dis…
Two-dimensional and three-dimensional band structures of the GaSe family of crystals have been calculated by the tight-binding method. The author's calculations fit the photoemission bandwidths well, particularly for the anion p x,y bands and, for GaSe, find similar band orderings and dispersions to those of M Schlute…
The precipitation of oxygen in bulk dislocation-free Czochralski silicon subjected to isothermal annealing at temperatures between 400 and 1100 °C is studied by means of infrared spectroscopy and transmission electron microscopy. From the changes in the infrared spectra observed after heat treatment it is concluded th…
Self-diffusion in cobalt is investigated from 896 to 1745 K by means of the standard radio-tracer method using lathe sectioning in the paramagnetic and sputter sectioning in the ferromagnetic region. The diffusion coefficients vary between about 10−17 cm2 s−1 and 10−9 cm2 s−1; their temperature dependence can be descr…
The results of experiments carried out in the HVEM may be influenced by radiation effects which occur during observation. The appropriate processes are reviewed. Atom displacement threshold energy data are compiled and the consequences for the applicable specimen thickness discussed for the case that experiments are p…
Molybdenum trioxide (MoO3) has been deposited onto single-crystal p-type silicon by neutralized ion-beam sputter techniques. The results indicate that the diode behavior is a function of oxygen partial pressure during the reactive sputtering. Film thickness, deposition rate, index of refraction, resistivity, and integ…
A simple null lens is described that is moved back and forth relative to a point source to provide large amounts of variable wave front aberration. This device can be used to test a wide variety of optical components and systems.
An analysis, in terms of Newman’s superposition model, of the cubic spin–Hamiltonian parameters for divalent manganese and trivalent iron in fluoroperovskite and II–VI compounds is presented. Values for the intrinsic parameter ?4 and for the power-law exponent t4 of Mn2+ with F−, S2−, Se2−, and Te2− ligands are report…
We report the preparation and electrochromic properties of iridium oxide films deposited by reactively sputtering iridium in a humidified oxygen discharge. These sputtered iridium oxide films (SIROFs) have the fast coloring and bleaching kinetics and excellent stability previously observed for anodically grown iridium…
A detailed account of a measurement of order parameter of a liquid crystal at the boundary by means of the wall-induced pretransitional birefringence is given. Several surface treatments were studied including surfactants and evaporated films. Although all treatments produced good alignment in the nematic phase, the b…
We present the results of an experimental and theoretical study of the thermal and thermoelectric properties of pure potassium for zero magnetic field and for fields up to 4.5 T, at temperatures of 1.5-4.2 K. The approximate quadratic dependence on field of the transverse thermal magnetoresistivity is found to be the…
The Judd-Ofelt (JO) theory was applied to interpret the optical-absorption intensities of trivalent neodymium (${\mathrm{Nd}}^{3+}$) in the garnets Ca${\mathrm{Y}}_{2}$${\mathrm{Mg}}_{2}$${\mathrm{Ge}}_{3}$${\mathrm{O}}_{12}$ and ${\mathrm{Gd}}_{3}$${\mathrm{Ga}}_{5}$${\mathrm{O}}_{12}$ and the biaxial crystal ${\math…
The infrared spectrum of CO chemisorbed on alumina-supported Rh surfaces has been studied following chemisorption at cryogenic temperatures. Major differences are observed in the distribution and spectroscopic character of chemisorbed CO species produced at low temperatures (110–170 K) compared to chemisorbed CO speci…
The construction of optical filters, which are required to have optical properties well defined over wide spectral regions, demands the use of multilayer designs in which there are no simple relationships between the thicknesses of the layers. There are considerable difficulties in the manufacture of such multilayers.…
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…