Materials Literature
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The photoluminescent and reflectance spectra of MgO smoke have been compared with the spectra of MgO ex-hydroxide and ex-carbonate. Parallel studies by electron microscopy have shown that a strong correlation exists between the optical spectra and the different morphology of the particles obtained by the different rou…
The inducible, mannitol-specific Enzyme II of the phosphoenolpyruvate:sugar phosphotransferase system has been purified approximately 230-fold from Escherichia coli membranes. The enzyme, initially solubilized with deoxycholate, was first subjected to hydrophobic chromatography on hexyl agarose and then purified by se…
Thermal expansion of γ-Mg2SiO4 was measured with X-ray powder diffraction method up to 750°C at atmospheric pressure. The data are analyzed in terms of Gruneisen's theory of thermal expansion and Gruneisen's parameter is obtained to be 1.27. Volume thermal expansion coefficient is 19 at 20°C and 27 at 500°C in unit of…
Nous avons mesuré les variations d'atténuation et de vitesse ultrasonores dans un gel acrylique. En comparant ces résultats avec ceux obtenus dans le solvant pur (H2O), nous avons pu en déduire la constante élastique propre du gel et le coefficient de friction entre le réseau et le solvant. Une étude en fonction de la…
A number of continuous random lattices can be classified as specific one-to-one mappings of ordered lattices of spaces of constant curvature onto the usual 3-dimensional euclidean space. These mappings put emphasis on two types of lattice defects : surface defects for spaces of constant positive curvature (i.e. spheri…
Atmospheric conditions, whether at room temperature or in high temperature ovens, do not consist of pure environments. Resorcinol-formaldehyde-latex (RFL) dipped nylon and polyester tire cords lose adhesion to rubber stocks upon exposure to environmental pollutants. Adhesion degradation is most severe upon exposure to…
The damage to three-dimensional orthogonal carbon-carbon composites created by particle impacts ranging from 1800 to 6000 ms-1 has been characterized for three weave constructions at both ambient and temperatures up to 3600¼C. The subsurface damage modes in the vicinity of the impact crater are described for the range…
The ultrasonic wave reflection method has been used to determine the elastic constants of various steels at the temperature range from room temperature to -196°C. Liquid nitrogen was used as a cooling agent. The data of the temperature dependence of elastic moduli for commercial alloys and steels were given in tables…
The fracture strength of two kinds of UO2 specimens possessing pores of different maximum sizes (60 and 140 μm) was measured in the range of room temperature − 1,300°C by means of diametral compression testing. The fracture strength thus obtained proved to be smaller than any of the values reported by previous authors…
It was found that sodium tetraphenylboron, NaB(C6H5)4, can be used as a reagent for determination of K in acid sodium acetate extracts of soils. After extraction and filtration, sodium hydroxide and formaldehyde are added prior to the reagent to avoid interference of ammonium. At low concentrations of K in the extract…
Thermodynamic relationships are derived which allow experimental enthalpy, entropy and free energy data for metal–hydrogen systems to be converted to conditions of constant volume. Discrepancies between these relationships and the equations developed by other workers are discussed. The relationships are used to conver…
CaO–MnO samples have been prepared by thermal decomposition of mixed carbonates and annealing of the resulting oxide mixtures at 1273 and 1523 K in vacuo. Cooled samples have been ground in vacuo and transferred for X-ray powder diffraction analysis and e.p.r. analysis without exposure to the atmosphere. Lattice param…
A brief summary is presented of the known effects of hydrogen on metals, especially degradation and embrittlement. Practical problems involving hydrogen are surveyed. Résumé On présente un bref résumé des effets connus de l'hydrogène sur les métaux, surtout en ce qui a trait à la dégradation et la fragilisation de ceu…
Abstract Garnet high temperature solutions, their solvents and binary systems consisting of lead oxide and one component out of the solute were investigated. The shear viscosity coefficients have been measured in a cylindrical rotation viscometer within the temperature range of liquidus or melting and not exceeding 12…
The behaviour of (i) the luminescence spectrum, (ii) the (relative) luminescence quantum yield and (iii) the luminescence lifetime of [Os(phen)3]2+(phen = 1,10-phenanthroline) and [with respect to (ii) and (iii)] of [Os(bipy)3]2+(bipy = 2,2′-bipyridine), has been examined in the temperature range 77–300 K, principally…
Abstract
Abstract γ Ag 8 GeTe 6 belongs to space group F [unk]3 m with Z = 4 and a = 11.58 ± 0.02Å. The arrangement of the tellurium atoms is almost precisely that of both the magnesium and copper atoms in the Friauf-Laves cubic phase of MgCu 2 . This arrangement produces 136 tetrahedra per unit cell, of which four are occupie…
The ballistic penetration behaviour of a high-strength aluminium alloy, 7001 T6, was investigated and targets of the alloy were found to fail in two modes, discing or plugging, depending on the orientation of the target in relation to the extrusion direction of the round bar from which it was cut. The dependence of fa…
The structure of hexabromobenzene, C6Br6, has been determined at 300 K by neutron powder diffraction. The crystal is monoclinic, a = 15.357 (4), b = 4.007 (1), c = 8.364 (2) Å, β = 92.65 (2)°, space group P21/n, Z = 2. The problem is well suited for a constrained refinement with the program EDINP. Within the accuracy…
Hot corrosion is the accelerated rate of oxidation of coatings and substrates, which occurs when a condensed phase is present on the surface. The major constituent of the corrosive deposit is sodium sulfate, although when fuels other than light distillates are employed, the deposit can contain various amounts of vanad…