Materials Literature
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Abstract Melt history, pressure, and crystallization temperature are three variables that may be used to vary spherulite size in polymer systems. In this study, bulk polypropylene samples were given various melt treatments and then isothermally crystallized under constant pressure. Spherulite size was found to increas…
On a utilisé les expériences de fluage pour mesurer la vitesse de montée des dislocations c. On trouve que la vitesse de montée varie avec la température avec une énergie d’activation do 1,80 eV, supérieure à celle de l’autodiffusion, et avec la contrainte, proportionnellement à σ2,7. Les estimations théoriques de la…
The article deals with the distribution and ecology of the Rhoicosphaenia, Diatomella, Mastogloia, Diploneis, Amphipleura, Frustulia, Brebissonia, Anomoeoneis and Stauroneis species known in Finland.
Article Crystal-structure refinements for orthorhombic boracite, Mg3CIB7O13, and a trigonal, iron-rich analogue was published on December 1, 1973 in the journal Zeitschrift für Kristallographie - Crystalline Materials (volume 138, issue 1-6).
A method of calculating the magnitude and direction of the instantaneous flux density in a thin lamination of magnetic material is described. The technique was demonstrated by measuring the rotating flux in samples of mild steel, grain-oriented silicon iron, and at a point in the T-joint of a three-phase, three-limbed…
The sequence of changes following experimental removal of a central region of one valve of Mytilus edulis included: (1) the secretion of periostracum similar to one of the three layers of normal periostracum; (2) calcification on the periostracum in a pattern corresponding to the form of the periostracal surface; (3)…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStabilization of the higher oxidation states of nickel. Molecular structure of bis(2,6-diacetylpyridine dioximato)nickel(IV)Gordon Sproul and G. D. StuckyCite this: Inorg. Chem. 1973, 12, 12, 2898–2901Publication Date (Print):December 1, 1973Publication History Published onl…
In the presence of NAD(+) the acylation by 1,3-diphosphoglycerate of the four active sites of pig muscle d-glyceraldehyde 3-phosphate dehydrogenase can be monitored at 365nm by the disappearance of the absorption band present in the binary complex of NAD(+) and the enzyme. A non-specific salt effect decreased the acyl…
Abstract The depolarization thermocurrent (DTC) method gives the dependence of the dielectric relaxation time on temperature. It has been used for investigations of relaxations obeying an Arrhenius‐like law in crystalline polymers. The analysis of this method shows it is possible to study mechanisms described by the W…
Abstract The molecular conformation and the crystal structure of α‐form poly‐ p ‐xylylene has been determined by x‐ray diffraction. The polymer has a monoclinic unit cell with a = 5.92, b = 10.64, c (fiber axis) = 6.55 Å, and β = 134.7°. Two chains pass through the unit cell, and the space groups is C2/m . The packing…
Abstract Stability determinations were made by solubility methods on two trioctahedral mica-derived vermiculites. The phlogopite-derived vermiculite was found to be unstable under acid solution conditions, where stabilities of montmorillonite, kaolinite and gibbsite had previously been determined. An attempt was next…
Abstract The nuclear magnetic resonance of 105 Pd has been observed in α‐PdH n for the first time. The resonant field was measured at 75°C as a function of hydrogen pressure p within the entire α phase region. A linear relationship between Knight shift and hydrogen concentration has been established by comparison with…
Chick cranial-bone procollagen, extracted at neutral pH in the presence of inhibitors of proteolytic enzymes, exists as a triple-stranded protein with disulfide bonds linking all three chains. The biosynthetic precursor function of this procollagen was demonstrated by pulsechase experiments. The ratio of radioactive h…
The present paper describes the isolation and identification of a major radioactive component of borotritide-reduced collagen, previously designated Fraction C. The derived structure for the compound confirms that it is identical with the ;post-histidine' component described by Tanzer et al. (1973) and given the trivi…
Low-temperature photoluminescence spectra are presented for Si crystals which have been irradiated with high-energy electrons. Studies of isochronal annealing, stress effects, and the temperature dependences of the luminescence are used to discuss the nature of the luminescent transitions and the properties of defects…
The stress corrosion cracking (SCC) behavior of sensitized Type 304 stainless steel has been studied in 288 C (550 F) primary water as a function of oxygen and fluoride contents of the water, stress level, prestrain, heat treatment, and surface preparation (tarnish film, surface ground, or pickled). Susceptibility to…
Abstract Passivity of iron in acidic solutions is ascribed to a thin film of iron‐deficient magnetite with the limiting compositions Fe 3 O 4 and Fe 2.67 O 4 . If the composition at the oxide/solution interface is close to the formula Fe 2.67 O 4 , it follows theoretically that the stationary corrosion current density…
N-terminal beta-galactosidase fragments are rapidly degraded in growing cells of Escherichia coli. Mutations in the lon gene are sufficient to enhance the stability of these polypeptides.
Summary The fine structure of the periphyton of Chara sp. from Wytham pond, Oxford, is examined using transmission and stereoscan electron microscopy. As a result of this investigation the structural proximity of each periphyte component as required by Wetzel and Allen's metabolic model of macrophyte‐periphyton intera…
1. Experimental progress curves were simulated for a reaction obeying Michaelis-Menten kinetics. 2. K(m) and V were estimated (a) by fitting the integrated Michaelis-Menten equation to the progress curves, and (b) from the initial slopes of the curves (i.e. from initial velocities). 3. The integrated equation could no…