Materials Literature
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Abstract Chemical analyses were carried out on individual particles in <2-μm size fractions to study smectite-palygorskite and smectite-sepiolite assemblages extracted from calcareous and dolomitic continental formations in Provence, southeastern France. A plot of the octahedral composition of 145 individual pa…
R. N. Edmonds, M. R. Harrison and P. P. Edwards, Annu. Rep. Prog. Chem., Sect. C: Phys. Chem., 1985, 82, 265 DOI: 10.1039/PC9858200265
Unlike decavanadate(6–), tetradecavanadophosphate(9–) shows pH-dependent differential rates of exchange of oxygen with solvent water. If the anion's structure is described as a Keggin-type ‘sphere’ with polar ‘caps,’ then at pH > 5 the caps are kinetically stabilised with respect to the ‘equator,’ whereas at pH < 1 th…
Abstract
The crystal and molecular structures of the title compounds [Cu4L34]·9CH3OH (3) and [Cu4L14]·8CH3CH2OH (4) have been determined from single-crystal X-ray diffraction data and refined to final R values of 0.062 (R′= 0.052) using 2 191 independent reflections for (3) and 0.062 (R′= 0.055) using 2 458 independent reflect…
Electrochemical methods have been used to study the crevice and pitting corrosion behavior of unalloyed titanium in chloride solutions at elevated temperatures (maximum 150 C). The investigation was focused primarily on crevice corrosion. The techniques which were used included simultaneous measurement of the corrosio…
Abstract Alcaligenes latus strain DSM 1123 has been tested for the production of Poly‐D(−3)‐3‐hydroxybutyric acid using sucrose as the only carton source. The strain is capable of accumulating the polymer associated to the growth very fast and lup to high concentrations in the biomass. Alcaligenes lotus seems to be ve…
Capacitive and inductive infrared mesh filters have been fabricated using electron-beam lithography combined with a lift-off procedure. A single level of PMMA was used to create positive tone patterns while a two-level metal-on-polymer process was used to create negative tone patterns. Resonant structures consisting o…
The crystal and molecular structures of the title compounds have been determined using three-dimensional X-ray diffractometer data and refined to a final R value of 0.0263 for bromo(3-dimethylaminopropan-1-olato)copper(II)(1), 0.0349 for chloro(3-dimethylaminopropan-1-olato)copper(II)(2), and 0.0268 for (3-diethylamin…
Abstract The chemical, morphological and mineralogical properties of two Enon sandy loam (fine, mixed, thermic Ultic Hapludalfs) soil‐saprolite profiles, one formed on gabbro and the other on metagabbro, are compared. Clay skins are scarce and stress cutans common in the argillic horizons of these soils. Iron‐manganes…
Dynamic thermogravimetry (tga), differential thermogravimetry (dtg), and Fourier Transform-Infrared Spectroscopy (FT-IR) were performed on a variety of celluloses with different cyr3tallinities. The data were compared to the crystallinlty indices (C.I.) determined by X-ray diffraction. Highly significant correlations…
"Zerodur", a glass ceramic, has been developed in order to have a material with an extremely small thermal expansion coefficient. The known physical properties are completed here by results on dimensional stability compiled over a number of years. Three samples of the material with different thermal histories show dif…
A critical assessment is made of the calculation procedures currently used for determining the cation distribution in spinels from X-ray powder diffraction data. Both binary and ternary spinels are considered. It is shown that X-ray powder diffraction, in conjunction with appropriate computational methods, has enough…
SummaryA systematic study of film growth on aluminium, over a wide range of anodizing conditions, encompassing barrier and porous-type films, has been undertaken to develop a more integrated theory of anodizing than previously possible. The broad findings are summarized, via schematic diagrams of film sections and imm…
Thermal cycling effects in a Cu-13.7 Al-4.0 Ni (mass%) alloy have been studied by optical and electron microscopy observations and X-ray diffraction. Transformation temperatures, Ms and Af, decrease gradually with increasing thermal cycles, the magnitude of the decrease reaching about 40 K after 10000 cycles. Martensi…
It has been experimentally demonstrated that micrometersized particles of graphite deposited on the surface of copper and niobium electrodes can promote the field emission of electrons in the range of 5-20 MV ·m-1. From measurements of the current-voltage characteristic, electron spectrum, and emission image of such s…
Tetraphenylporphinatoiron (III) catalyzed the reductive activation of molecular oxygen in the presence of NaBH4 and Me4NOH. Several olefins were oxidized with this system and oxidized products were isolated in high yields.
A chitosan film was newly prepared from the liquid crystal solution. The unit cell parameters of crystal were determined: a=8.67 Å, b=10.24 Å (fiber axis), c=8.92 Å, and β=92.6°. These parameters accorded with those of the (1-3) crystal reported previously within an experimental error. In addition, the packing of mole…
We summarize the current status of our studies of the macroscopic linear mechanical properties of nematic liquid crystals formed from solutions of rigid or semirigid rod-like polymers. The polymer system we have studied is a racemic mixture of poly(benzyl glutamate) dissolved in a mixture of dioxane and methylene chlo…
The Landau-de Gennes free energy expansion coefficients for nematic polymers are evaluated on the basis of a molecular-statistical model. It is proved that the obtained expansion provides a reliable qualitative description of the phase transition to the nematic state for polymers with arbitrary molecular length and ri…