Materials Literature
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VO2 (A), a metastable phase of VO2, was prepared by hydrothermal treatment of an aqueous VOSO4 solution. (VO2 (A) has tetragonal symmetry but the crystal structure remains unknown. DTA and magnetic susceptibility measurements revealed a transition at 162°C which was detectable on heating but not on cooling. Semiconduc…
Abstract A recently developed analytical technique, modulus profiling, conveniently allows the mechanical properties of elastomers to be mapped with spatial resclutions approaching 0.05 mm. Thus, spatial heterogeneities in modulus caused by processing and aging phenomena can be easily monitored. This paper describes s…
The essential equations of solid–solid nucleation theory are summarised and the origins of the accelerated nucleation kinetics observed at grain boundaries are examined on this basis. Methods of measuring nucleation kinetics at grain boundaries are critically reviewed and the precautions which must be taken in order t…
Abstract Metalloporphyrin-catalyzed reduction of dioxygen by ferrocene derivatives occurs efficiently via outer-sphere electron transfer from ferrocene derivatives to metalloporphyrins (MTPP+), followed by acid-catalyzed reduction of dioxygen by MTPP in the presence of perchloric acid in acetonitrile.
The anisotropy of magnetic properties in non‐oriented electrical steel sheets can be evaluated by measuring Epstein specimens in the radial directions. The magnetic properties measured on ring cores are practically equal to the approximate values of magnetic properties determined by Epstein specimens in the radial dir…
Alloy 718 is extensively used by the oil and gas industry for Critical Service applications involving both wellhead components and downhole auxiliary equipment for corrosive/sour service. This study addresses the metallurgy and precipitation behavior of this alloy and their effects on fracture resistance. The use of h…
Abstract Five new optically active crown ethers and six optically active dipodands are reported. The crown ethers were synthesized by using (+)-(1S,4R,5S,8R)-2,3:6,7-dibenzobicyclo[3.3.1]nona-2,6-diene-4,8-diol and (+)-(1S,4R,5S,8R)-4,8-bis(hydroxymethyl)-2,3:6,7-dibenzobicyclo[3.3.1]nona-2,6-diene as a chiral subunit…
Chlorided Pt/Al2O3 catalysts have been subjected to a series of consecutive oxidation / reduction cycles and the quality of Pt dispersion after each reduction stage monitored by infrared study of adsorbed CO. Low-temperature (613 or 723 K) oxidation treatments failed to improve Pt dispersion after subsequent reduction…
The anomalous high-index faces (hkl) of the mineral calaverite (Au1 - xAgxTe2) measured goniometrically in the year 1931 by Goldschmidt, Palache & Peacock [Neues Jahrb. Mineral (1931), 63, 1-58] are re-interpreted and related to the wave vector q of the displacive incommensurate modulation which was recently found in…
The reactivity towards carbon monoxide of a series of Zn–Cr non-stoichiometric spinels (NSS) with an excess of zinc, active in the synthesis of methanol and higher alcohols, has been investigated by infrared spectroscopy and adsorption microcalorimetry. A fraction of the total CO taken up is irreversibly oxidized to s…
The physical properties of a carpet, especially the mechanical and optical properties, largely determine its performance as a floorcovering. The mechanical properties influence the walking comfort and are closely linked to the changes in appearance during wear. New instrumental techniques, notably those using digital…
Seven novel fungitoxic sesquiterpenoids, chokols A, B, C, D, E, F and G, were isolated from stromata of Epichloe typhina on Phleum pratense. Their structures were determined by spectroscopic methods. The absolute configuration of chokol E was elucidated by its CD spectrum with Eu(fod)3 and a chemical correlation with…
Quality, appearance, and tactile properties of textiles arise from the choices of fibre type, linear density, staple length and degree of crimp, yarn linear density, mass, and twist, and fabric mass, weave type, density, and type of finishing, and especially the types of fibre assembly chosen. Information on how these…
Abstract Graft polymerization of maize starch with acrylic acid using potassium persulphate as free radical initiator was investigated under different conditions. Variables studied included initiator concentration, acrylic acid concentration, starch/water ratio and polymerization temperature. The carboxyl content of t…
Our recent studies of ferroelectric chiral smectic and super-twisted nematic (ST) multiplexed-matrix liquid-crystal displays (LCDs) and a thin-film-transistor (TFT) active-matrix twisted nematic (TN) LCD are presented, mainly in terms of liquid-crystal material and cell optimization. This is based on a consideration o…
ABSTRACT: Analytical transmission electron microscopy (ATEM) was used to obtain chemical analyses of single illite crystals from Upper Carboniferous reservoir sandstones ofthe Bothamsall Oilfield, East Midlands, UK, and from Rotliegendes (Permian) sandstones of the North Sea. All samples were found to be highly alumin…
The scheme previously proposed by the authors on the basis of the Taylor model to deal with the deformation of polycrystals caused by the stress induced martensitic transformation (SIM) has been futher extended to describe the recovery stress associated with the reverse transformation upon unloading. According to this…
The unusually highly puckered macrocyclic core of the title compound confirms proposed conformational changes which are essential for the facile aerial oxidation of phenolic porphyrins, such as meso-tetrakis(3,5-di-t-butyl-4-hydroxyphenyl)porphyrin (1).
Irradiation of the benzene solution of l-(2-vinylpheny1)-2-(2-furyllethenes (71 resulted in the formation of furo(3.2-bl-6.7benzobicyclo[3.2.llocta-2,6-dienes (101 as the main product.The structure of the products was determined by spectroscopic data.Intramolecular photochemical cycloadditions of o-divinylbenzene (1)…
Some CaO–SiO2–H2O gels of controlled composition have been synthesised by the hydrolysis of mixed alkoxide precursors and by direct reaction between colloidal SiO2 and Ca(OH)2. The gels were equilibrated with water at 25 °C after different ageing treatments, and the water compositions analysed. A mathematical model de…