Materials Literature
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Fourier-transform mid-infrared (FTIR) and near-infrared (NIR) spectroscopies have been used to investigate the effects of thermal history on the bulk and surface structure of monolithic silica gels and glasses prepared by the sol–gel route. Effective dehydroxylation occurs above 700 °C with consolidation of the bulk s…
Cocondensation of scandium vapour with 1,3,5-tri-tert-butylbenzene affords the first example of a scandium(0) complex, the sandwich compound bis(η-1,3,5-tri-tert-butylbenzene)scandium; ESR and UV studies also the reveal the presence of a second compound from this reaction, formulated as a similarly unique example of s…
Abstract Partially acetylated cellulose was synthesized by homogeneous acidic and basic saponification of cellulose triacetate (fully acetylated cellulose) and by homogeneous acetylation of cellulose dissolved in molten N ‐ethyl‐pyridinium chloride. The result of 1 H NMR spectroscopic investigations was that acetylati…
An active catalyst for carbon dioxide hydrogenation is obtained by exposing an amorphous Au25Zr75 alloy to CO2 hydrogenation conditions. During this in situ activation, metallic gold particles of 8.5 nm mean size are formed, and the zirconium component of the catalyst is oxidized to ZrO2. For comparison, a further Au/…
Bagasse fiber was acetylated with acetic anhydride alone to various levels of acetyl weight gain. Acetylation causes the bagasse fiber to become more hydrophobic, as evidenced by a lowering of the equilibrium moisture content as the level of acetylation increased. Acetylated bagasse fiber and fiberboards made from ace…
The use of organosilanes as adhesion promoters for surface coatings, adhesives and syntactic foams is described and reviewed in the light of published work. Data are presented on the beneficial effect of silanes, when used as pretreatment primers and additives, on the bond strength of two pack epoxide and polyurethane…
The hydrolysis of alkoxysilane coupling agents has been followed using proton NMR. The disappearance of the silane ester and the appearance of the alkoxy group were observed to follow pseudo-first-order kinetics. The apparent rate constant was found to be dependent on the concentration of the silane coupling agent and…
The zero-temperature energies and equilibrium volume expansions of point-defect-free asymmetrical grain boundaries (GBs) in bcc metals are determined using both a many-body potential fitted for Mo and a Johnson-type pair potential spline-fitted for α-Fe. The asymmetrical combinations of lattice planes considered invol…
Scattering has often been regarded as a problem in all aspects of medical radiation physics. The contribution of scatter to radiotherapy beams causing increased penumbra, the production of staff doses during diagnostic X-ray procedures or the contribution of scatter to image degradation in radiology have all been cite…
The phase-transition behaviour of mixtures of liquid crystals (LCs) and photochromic spiropyran derivatives, induced by isomerization of the guest molecules, has been investigated. Two types of spiropyran derivatives were employed: normal spiropyrans which are stable in the closed form (spiropyran form; SPF) and open-…
In the dark, both photochromic forms of co-polymer 1 (R = H, CH3; R1 = CN, OCH3) are indefinitely stable at room temperature. In combination with their mesomorphic properties, this stability makes these materials interesting for optical information storage.
Cyclic fatigue in ceramics is reviewed, focusing on recent research. Several cyclic fatigue mechanisms hereby proposed are summarized briefly in section 3. In section 4, fatigue characteristics of all available materials are explained. Alumina, silicon nitride and lead zirconate titanate (PZT)are prone to cyclic fatig…
Tetra(N-methyl-4-pyridyl)porphyrinatoiron(III) pentachloride and its N-methyl-2-pyridyl isomer have been adsorbed onto the highly crosslinked cation ion-exchange resin Dowex MSC1 and have been used to catalyse the reaction of Z-cyclooctene with iodosylbenzene in methanol. Two oxidation products have been detected, epo…
Copper oxide was deposited on a zinc aluminate prepared from high specific area alumina and zinc nitrate. The activity of the solid obtained has been measured in the catalytic combustion of methane before and after an aging test performed at 1340 K. The environment of the copper species was followed by UV–VIS reflecta…
Molecular assemblies within Langmuir–Blodgett (LB) films of 1,4,8,11,15,18-hexaoctyl-22,25-bis(carboxypropyl)phthalocyanine (1a) copper 1,4,8,11,15,18-hexanonyl-22,25-bis(carboxypropyl)phthalocyaninate (1b) and 1,4,8,11,15,18-hexadecyl-22,25-bis(carboxypropyl)phthalocyanine (1c) have been examined using X-ray diffract…
Acid treatment of Ca2+ montmorillonite has been shown to increase significantly its effectiveness as a support for ZnCl2 Friedel–Crafts alkylation catalysts; optimum treatment conditions have been established and evidence is reported for a synergistic interaction between absorbed salt and acid-activated clay.
Previous analysis of the distribution of experimental solvent molecule positions around amino acid side chains showed that distinct clustering occurred close to polar or charged atoms in proteins. We have used those data to predict likely solvent positions around proteins not used in our initial analysis. We envisage…
Heat-capacity C(T) data on the title materials, as well as on CuO for comparison, were obtained with use of a differential scanning calorimeter to a precision of \ensuremath{\simeq}0.1--1%. The measurements were carried out (i) to characterize the thermal anomaly at the tetragonal-orthorhombic transition temperature $…
There have been a great deal of progress in the development of high performance silicon nitride and sialon ceramics, largely owing to better understandings of sintering phenomena and processing-microstructure-properties relations. In this paper, sintering mechanisms and factors affecting sintering are reviewed for the…
A direct approach to the investigation of the reflection of electromagnetic waves from a plane interface separating a vacuum half-space and a stratified anisotropic layer is presented. The formulation involves the generation of a Riccati differential equation for a certain 2*2 reflection matrix. The approach is alread…