Materials Literature
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The effect of a magnetic field applied perpendicular to the helical axis of a cholesteric liquid crystal mixture with positive diamagnetic anisotropy has been studied by laser diffraction and microscopy. A rapid decrease of the field below a threshold H s generates first a metastable periodically striated texture. A f…
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Chlorided Pt/Al2O3 has been subjected to series of consecutive oxychlorination/reduction cycles in which oxychlorination stages in each series involved heat treatment of Pt/Al2O3 at 723, 893 or 993 K in oxygen containing 400 ppm carbon tetrachloride. The quality of resulting Pt dispersion was monitored by infrared and…
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In searching the elements to suppress the intergranular brittleness in molybdenum, TiC addition was found effective. In order to clarify the effect of TiC addition quantitatively, molybdenum bicrystals containing 1.5 mol%TiC were prepared by a floating zone melt technique. The fracture behaviour was measured by a 4-po…
Abstract Das thermische Verhalten von RbGeI 3 wurde unter Verwendung von Röntgenbeugung, Ramanspektroskopie und DTA/DSC untersucht. RbGeI 3 ist tetramorph. In der Kristallstruktur der gelben orthorhombischen LT‐Form (RG P2 1 2 1 2 1 ; a = 10,1441 (8) Å; b = 4,5460(5) Å; c = 16,8438(9) Å), die durch Kristallisation aus…
A simple method which is suitable for determining with reasonable precision the lattice parameters of the crystals with known structure using a 16-bit personal computer and an unsophisticated calculation is described. This procedure is based on the Nelson-Riley extrapolation function and the least-squares analysis. Th…
The effects of maleic and fumaric acids and their mono- and di-anions on the dissolution of calcite in aqueous solution have been studied over a wide pH range (3–8.5) by (i) the channel flow cell method, (ii) etch pit morphology measurements and (iii) the determination of adsorption isotherms. It is established that t…
Abstrac tAn improved model for the atomic oxygen oxidation of silver is presented. The transport of oxygen through the oxide layer is modelled using two transport mechanisms, namely gas flow through micro-pores and Fickian diffusion. Both processes exhibit parabolic growth. The interfacial reaction between oxygen and…
Various NADH model compounds, 1-(X-benzyl)-1,4-dihydronicotinamide (X-BNAH: X = 4-MeO, 4-Me, H, 4-Cl2, and 2,4-Cl2) and 10-methyl-9,10-dihydroacridine (AcrH2), form complexes with metalloporphyrins (FeTPPClO4, FeTPPCl, MnTPPClO4, and ZnTPP; TPP: tetraphenylporphyrin) in dichloromethane or chloroform. For the BNAH–ZnTP…
In order to improve the understanding of pollution or moisture-triggered flashovers a joint four-year test was initiated to evaluate DC insulators under natural pollution and wetting conditions. The main purpose of the test is to establish correlations among flashover, equivalent salt density deposits, and weather, op…
The monoclinic form of LiMgBO 3 has been synthetized and its crystal structure studied by single crystal X-ray diffraction methods. The space group is C 2/ c , Z = 8, with unit cell parameters a = 5.161(1) Å, b = 8.880(2) Å, c = 9.911(2) Å and β = 91.29(2)°. The structure which is isotypic to that of i.a . LiZnBO 3 ,…
Abstract The rheological and thermal properties of poly(vinyl alcohol) (PVA) gels prepared through freezing‐thawing cycles were studied, in order to clarify the relation between structure and functional properties. The breaking strength of PVA gels increases with increasing the degree of saponification (DS), i.e. the…
The chelation of spironaphthoxazine derivatives in the coloured form to divalent metals induced considerable shift of the absorption spectra and significant retardation of the decolouration rate in the dark.
Abstract This article discusses the classifications of high-speed tool steels and describes alloying elements and their effects on the properties of high-speed tool steels. It analyzes the heat treatment of high-speed tool steels, namely, preheating, austenitizing, quenching, and tempering. Surface treatments for the…
Nine structural metals were evaluated for relative nonflammability, in a high pressure oxygen environment. The metals studied were: 316, 321, 440C and 17-4 PH stainless steels (SS), Inconel 600, Inconel 718, Waspaloy, Monel 400, and Aluminum 2219. A comparison is made between four methods which have been used to provi…
This paper examines some of the properties of Alloy 718 required by the oil and gas industry for the completion of corrosive wells. The properties of interest include strength, toughness, pitting and general corrosion resistance, hydrogen embrittlement resistance, and stress corrosion cracking resistance. The effects…
The spark decomposition of mixtures of SF/sub 6/ (partial pressure from 100 to 500 kPa) and water (concentrations between 600 and 2000 VPM) has been studied. The sparks were generated between a point (stainless steel) and a plane (aluminum) either under 50-Hz AC voltage or by discharging a capacitor. Owing to the high…
Abstract Today, material science is directed towards the development of multifunctional and oriented structures. One example of such supramolecular systems are liquid crystalline (LC) elastomers which combine the properties of LC phases (the combination of order and mobility) with rubber elasticity, one of the most ty…
110 to 500 kV mountain power transmission lines in operation in the USSR are discussed. Since 1967 a 100 kV line has been in service at an altitude up to 3.58 km above sea level. A recent 100 kV overhead line is at =4 km, its entire 224 km length running above 1.8 km and at least 65% of its right-of-way lying in mount…