Materials Literature
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Analyses of high-resolution neutron powder diffraction data, using both the Pearson VII and pseudo-Voigt peak shape functions, have revealed a range of peak shapes from essentially Gaussian to Lorentzian and beyond. Moreover, the refinements show that the Lorentzian character of the peaks in each pattern increases wit…
Abstract Hydroxide and oxyhydroxide products of aluminum were formed at room temperature at an initial Al concentration of 2 × 10 -3 M, pH 8.2, and at varying concentrations of organic and inorganic ligands commonly found in nature. The effectiveness of the ligands in promoting the formation of noncrystalline products…
No abstract available.
Whisker‐reinforced ceramic composites with enhanced fracture toughness properties are being developed. The creep behavior of such a composite was studied. The introduction of silicon carbide whiskers significantly improves the creep resistance of polycrystaline alumina.
CONTENTS PERSPECTIVES AND SUMMARy 189 GENERAL PROPERTIES OF THE POLYMERIZING UNIT 190 Actin 190 Tubulin 191 ASSAY METHODS FOR THE POLYMERIZATION PROCESS 192 Actin 192 Tubulin 193 THE SIMPLE MODEL FOR ACTIN AND TUBULIN POLYMERIZATION 194 Kinetic Theory 195 Experimental Results 197 Fragmentation and Reannealing 200 THE…
Relationships between surface sediment diatom assemblages and lakewater characteristics were studied in 38 lakes in the Adirondack Mountains of northern New York. Most of the lakes are dilute, poorly buffered, and oligotrophic to mesotrophic. The diatom flora (240 taxa identified) is typical for circumneutral to acidi…
The stable double-bond isomers 1 and 1′ were one of the surprises which the seldom investigated 1,5-diazocines have had to offer. In all other substituted compounds of this class only one isomer with fixed double bonds exists. The dianions are symmetric, diatropic 10π systems with delocalized π bonding; the radical an…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCarbon dioxide insertion into the methyl-indium .sigma. bond of methylindium(III) porphyrins. Molecular stereochemistry of (acetato)(2,3,7,8,12,13,17,18-octaethylporphyrinato)indium(III)P. Cocolios, R. Guilard, D. Bayeul, and C. LecomteCite this: Inorg. Chem. 1985, 24, 13, 2…
The sintering behavior of compacts of ultrafine silicon powder (0.02 to 0.1 μm particle size) was investigated. Two sintering modes occur: normal sintering associated with densification and subnormal sintering without densification. The micro‐structure developed in normal sintering has a fine grain size (0.05 to 0.3 μ…
Abstract In this paper a brief description of the synthesis of silicone polymers and their compounding is given, and the wide range of properties available in Silastic® Registered trademark of Dow Corning Corporation. silicone rubber is discussed. Some of the key properties are related to several applications. These i…
Abstract Polycarbonate (PC), one of the leading engineering plastics, suffers from deterioration under harsh environmental conditions. It is sensitive to the effects of light (UV) radiation, to thermal degradation, and to the attack of hot water, due to hydrolysis. By exposure of various commercial PC grades—at variou…
Photostriction explainable by the superposition of the bulk photovoltaic effect and piezoelectricity has been investigated intensively in the solid solution ceramics (Pb, La) (Zr, Ti)O3 from an applicational point of view. Three key points are described for improving response speed of the photostriction; composition s…
Thallium‐probe ion luminescence spectroscopy and X‐ray photoelectron spectroscopy were used to study the structure of sodium aluminosilicate glasses. It was demonstrated that the O1s spectral envelope for these glasses is comprised of three energetically distinct peaks, two attributed to bridging oxygen atoms (Si‐O‐Si…
Abstract Small-angle X-ray powder diffraction analyses and high-resolution electron microscopy of allophane samples (SiO 2 /Al 2 O 3 ratio, 1.12 to 1.68) showed that allophanes consist of nearly identical spherical particles with diameters of about 40 Å and retain their characteristic “hollow” spherical morphology at…
Abstract Ac impedance investigations were performed at high‐purity iron and mild steel in de‐aerated 10% hydrochloric acid under free corrosion at room temperature in the presence of quaternary ammonium compounds. Systematic studies of specially selected and synthesized pyridinium and quinolinium derivatives revealed…
This paper describes the adaptation of Rouard’s method, a familiar computational technique used in thin-film coating design, to the analysis of waveguide diffraction gratings. The approach can be used to generate the spectral and the angular characteristics of arbitrary straight-line gratings (periodic or nonperiodic)…
A code written in BASIC is described which calculates x-ray spectra for tube voltages from 20 to 150 kVDC. Data for the spectral distribution, the mean photon energy, kerma in air, mean energy of the kerma distribution together with 1. and 2. half-value layers for aluminum are obtained. Numerical values for the differ…
The MLCT (Metal to Ligand Charge Transfer) excited state of the Ru(bipyrazine)3(2+) is quenched by a series of organic amines and methoxybenzenes, in acetontrile solution. Linear Stern-Volmer plots were obtained, and various rate parameters were extracted from the data. The excited state is also quenced in neutral aqu…
Our identification of a family of genetically distinct collagens specifically distributed in the connective tissue of muscle now poses questions on their possible role in myoblast differentiation, muscle development, turnover and function in the living muscle, and post-rigor in the tenderness of meat. Using collagen-t…
Four nickel-bearing clay minerals from New-Caledonia belonging to the lizardite-nepouite and the kerolite-pimelite series have been investigated in order to study the mechanisms of Ni-Mg substitution. Local order around Ni was determined by optical absorption spectroscopy and X-ray absorption spectroscopy at the Ni-K…