Materials Literature
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In recent years methods of data analysis for point processes have received some attention, for example, by Cox & Lewis (1966) and Lewis (1964). In particular Bartlett (1963a, b) has introduced methods of analysis based on the point spectrum. Theoretical models are relatively sparse. In this paper the theoretical prope…
Prior small-polaron hopping theories have tacitly assumed that the lattice relaxes rapidly enough after a jump to permit the treating of successive hops as independent. We conclude that the appropriate relaxation time is too long to permit consistent application of these theories to intermediate-mobility materials suc…
Abstract An investigation is made of the stability of the shape of a moving planar interface between the liquid and solid phases in the freezing of a dilute binary alloy. A nonlinear model is used to describe an experimental situation in which solidification is controlled so that the mean position of the interface mov…
YbP${\mathrm{O}}_{4}$ was found to show weak green (497 nm) luminescence when excited by infrared (1 \ensuremath{\mu}m) light. It is concluded, on the basis of measurements of excitation intensity dependence and decay time, that this luminescence is due to the emission of a photon by a pair of excited ${\mathrm{Yb}}^{…
For some ferrites, containing copper and manganese an investigation was made of the influence of the modification of the cation distribution on the Curie point and the anomaly of the temperature variation of the resistivity in this point. The cation distribution was modified by oxygen treatment and was proved by satur…
A detailed neutron diffraction study of Pd2MnSn and Cu2MnIn shows that both have the fully ordered L21 type of Heusler alloy structure and are ferromagnetic with 190 and 575 °K as their respective Curie temperatures. Pd2MnGe shows a preferentially disordered L21 structure with 0.98 Pd + 0.02 Mn on the A- and C-sites a…
A theory of the thermal mechanism of the switching phenomenon is presented which accounts for the essential experimental features reported. The expressions deduced may be used for sandwich and coplanar thin film structures. The theory gives a quantitative basis to decide whether a certain switching behaviour is therma…
Measurements of the IR optical properties of PuO2 were performed by room temperature reflectivity at normal incidence, and absorption. Results of reflection, analysed by Kramers-Kronig and classical dispersion analyses, are fitted into a dynamical theory of fluorite structures. A comparison is established with UO2 and…
The i.r. and laser Raman spectra of pure, crystalline Caro's acid, H 2 SO 5 , were measured for the first time between 4000 and 30 cm −1 . Most of the fundamental vibrations of the molecule could be identified by comparison with those of the H 2 SO 4 , H 2 O 2 and HSO 5 − species. In addition, a dozen or so of lattice…
Vacuum ultraviolet absorption in alkali-nitrites (NaNO 2 and KNO 2 ) and alkali-nitrates (LiNO 3 , NaNO 3 , KNO 3 , RbNO 3 and CsNO 3 ) has been investigated in the region from 5 to 23 eV at room and liquid nitrogen temperatures. Two types of absorption bands are observed for each of these salts with polyatomic anions…
K2MoO4, K2WO4, Rb2MoO4, and Rb2WO4 are monoclinic and isomorphous: Cs2MoO4 and Cs2WO4 are isomorphous with orthorhombic b-K2SO4. Cell consts. and at. parameters are calcd. from powder data, and the powder patterns are given. [on SciFinder (R)]
The evaluation of the elastic scattering differential cross section of electron scattering from a planar surface of a vibrating lattice is reduced to the solution of a set of coupled algebraic equations for the associated scattering amplitude. This reduction is valid both for overlapping potentials (thus removing the…
Single crystal samples of tellurium obtained from small diameter ingots, specially grown by the Czochralski method from a melt of the purified element, were studied by measuring the electrical conductivity (σ), Hall coefficient (R H ), and transverse magnetoresistance (Δρ/ρ 0 ). As a result of annealing and etching, t…
Three different types of radiationless transitions play a role in the radiationless decay of the luminescent Eu3+ center in LaAlO3: (a) a temperature-independent process from the charge-transfer state, (b) a temperature-dependent process (ΔE = 0.15 eV) from this state, (c) a temperature-dependent process (ΔE = 1.1 eV)…
Electrical properties of hydrides and deuterides of zirconium have been investigated between 1.1 and 410\ifmmode^\circ\else\textdegree\fi{}K. The metallic nature of these materials is evident in the fact that for compositions approaching Zr${\mathrm{H}}_{2}$, the hydride is a better conductor than is high-purity zirco…
This paper reports the study of the photogeneration and charge transport of holes in evaporated samples of vitreous ${\mathrm{As}}_{2}$${\mathrm{Se}}_{3}$. The photogeneration is characterized by a field-dependent quantum efficiency which is similar to that found in vitreous Se. The charge transport is described by as…
A solution to the linearized Boltzmann equation has been found that describes the galvanomagnetic properties of metals. The use of a vector mean-free-path function results in a solution for the conductivity tensor that is valid for any strength and orientation of the applied magnetic field. A discussion is given of th…
Summary The mineralogy of the processes leading to the formation of soils by the tropical weathering and leaching of rocks is reviewed, and illustrated by the results of an investigation into the formation, mineralogy and plasticity properties of some soils formed on basalt, granite, shale and sandstone in west Malays…
The 1000-Hz 300\ifmmode^\circ\else\textdegree\fi{}K dielectric constants of some alkali halides were measured to an accuracy of 0.01% by the method of substitution. Reproducibly different values for various crystals of the same type were obtained which varied beyond the experimental error. The ranges of results for va…
It is shown theoretically that the orientation pattern of cholesteric liquid crystals can be less stable in electric and magnetic fields than was previously thought. Specifically, the planar texture between two conducting glass plates may become unstable at voltages much below those needed to unwind the cholesteric he…