Materials Literature
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An expression is derived for the conductivity due to variable range hopping in a density of states which varies as a power of the energy from the Fermi level. The derivation is also given for the case of two-dimensional hopping.
Amyloid fibrils and the aminoterminal variable fragment of some Bence Jones proteins are known to have Congo red affinity and, after staining, to exhibit dichroism, polarization birefringence and a green polarization color. X-ray crystallographic analysis demonstrates the presence in these preparations of a 4.72-4.76Å…
The interaction of a protein inhibitor with the catalytic subunit derived from adenosine 3′,5′-monophosphate-dependent protein kinase is described. A kinetic analysis of casein phosphorylation in the presence of inhibitor reveals a noncompetitive interaction between the inhibitor and the catalytic subunit substrates,…
Cordierite sector trillings, which are found well developed in some A1-rich volcanic rocks and pelitic buchites, are thought to have formed initially as hexagonal high cordierite crystals. Subsequent ordering of the (Al, Si) configuration in the crystal structure would have produced the present orthorhombic modificati…
Abstract Comparison of the reflectance spectrum of cellulose with that of myoinositol, cycloheptaamylose, and other model compounds indicates that the acetal linkage does not contribute significantly to the absorption peak at 260 nm. The spectra of photolyzed and photo‐oxidized cellulose suggest that ketonic carbonyl…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThermal decomposition of aliphatic monoaminomonocarboxylic acidsP. G. Simmonds, E. E. Medley, M. A. Ratcliff, and G. P. ShulmanCite this: Anal. Chem. 1972, 44, 12, 2060–2066Publication Date (Print):October 1, 1972Publication History Published online1 May 2002Published inissu…
The structures of NaNb03 in the S phase (480°-520°c) and T1 phase (520°-575°c) have been determined by use of the octahedron tilting schemes of Glazer. Both phases are orthorhombic with unit cell edges approximately twice those of ideal perovskite; their space groups are Pnmm and Ccmm, respectively. An explanation of…
These experiments are a continuation of earlier work on the resistance of diamond to abrasion whilst being polished and ground. The most striking feature of the results is the very great difference in the resistance, or abrasion hardness, observed on the various faces for different directions of abrasion. A discussion…
SrCoO 2.5 with brownmillerite (4CaO·Fe 2 O 3 ·Al 2 O 3 ) type structure is an antiferromagnet with the Néel temperature of 570 K. The magnetic structure as determined from a neutron diffraction study is of G-type and the Co 3+ magnetic moment is 3.3±0.5µ B at liquid nitrogen temperature.
The ternary intermetallic compounds CaBe 2 Ge 2 , BaMg 2 Pb 2 and BaZn 2 Sn 2 have been prepared. Their crystal-structures have been determined. They are isotypic and crystallize in a new variant of the BaAl 4 -type (Space group: P4/nmm — D 4h 7 , lattice parameters: CaBe 2 Ge 2 : a = 4,02 ± 0,02 Å c = 9,92 ± 0,02 Å B…
In the ferrimagnetic rare-earth cobalt compounds, the reciprocal susceptibility obeys a N\'eel-type law. As a function of rare-earth content, the paramagnetic moments of cobalt atoms vary similarly with those deduced from saturation measurements. Particularly, for $R{\mathrm{Co}}_{2}$ ($R=\mathrm{G}\mathrm{d},\phantom…
Samples of the system SrCo 1- x Fe x O 3- y (0≤ x ≤1, 0≤ y ≤0.5) have been prepared under varying oxygen pressure and temperature and their crystal-lographic and magnetic properties have been studied. SrCoO 2.5 with brown-millerite type structure (high temperature phase) is an antiferromagnet with the Néel temperature…
Abstract The formation of junctions between a moving dislocation and the trees of a dislocation forest has been calculated for f.c.c. crystals. In contrast to previous estimates the concept of the orientation‐dependent line energy and a more realistic averaging procedure was used. In a random forest in which the tree…
It was found by microprobe analysis that during corrosion of stainless steel and mild steels in chloride solutions the most susceptible sites for pit nucleation were the inclusions of manganese sulfide. In the case of stainless steels, the corrosion pits were initiated mainly at mixed manganese and iron sulfide inclus…
The crystal structures of realgar, AsS and orpiment, AS 2 S 3 were refined using diffractometer data. The cell dimensions of realgar are: a = 9.325 ±.003 Å, b = 13.571 ± .005 Å, c = 6.587 ± .003 Å, β = 106° 23′ ± 5′, and those of orpiment are: a = 11.475 ± .005 Å, b = 9.577 ± .004 Å, c = 4.256 ± .002 Å, β = 90° 41′ ±…
The polymerization of lactones provides a facile route to polyesters that is unimpeded by the long reaction cycles and elevated temperatures inherent in the condensation of hydroxyl and acid functional groups. Depending on the structure of the lactone monomer, catalyst/initiator systems are known which allow preparati…
The mean-square end-to-end distance and the second virial coefficient are evaluated for stiff chains with excluded volume. The calculation is based on a wire-bead model whose backbone in the unperturbed state obeys wormlike-chain statistics. In order to establish the necessary distribution functions, results derived i…
High‐temperature diffusion kinetics and phase relations between couples of fused SiO 2 or cristobalite and sapphire or mullite were investigated in air and in helium. Subsolidus liquid formation between sapphire and cristobalite indicates the existence of a metastable system without mullite. A liquid phase is consider…
The electrical relaxation associated with alkali diffusion in Na 2 O·3SiO 2 glass was studied from 0.2 Hz to 700 kHz at –1° to 163°C. A formalism for analysis of electrical relaxation in conducting dielectrics which associates the nonexponential decay of the electric field to zero and the dispersions in the dielectric…
A neutron diffraction study was carried out on SrFeO 3 . The results indicate that the magnetic structure is a helical one with the helicoid vector k ; k //<111> and | k |=0.112 a * . The Fe 4+ magnetic moment is 2.7±0.4 µ B at liquid nitrogen temperature.