Materials Literature
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An enzyme system of Mycobacterium smegmatis catalyzing the elongation of medium-chain fatty acids with acetyl-CoA was obtained free from de novo fatty acid synthetase by ammonium sulfate fractionation. The system was resolved by gel filtration and DEAE-cellulose chromatography into three fractions, all of which were r…
The lattice parameter of NiO from 105 K to 813 K has been measured using the X-ray diffraction technique. An orthogonal polynomial of second-order with least square error approximation is fitted to the lattice parameter versus temperature data to obtain the thermal expansion coefficient, α. The high temperature values…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCrystal and molecular structure of the free base porphyrin, protoporphyrin IX dimethyl esterWinslow S. Caughey and James A. IbersCite this: J. Am. Chem. Soc. 1977, 99, 20, 6639–6645Publication Date (Print):September 1, 1977Publication History Published online1 May 2002Publis…
Formulas for the tensor permeability of partially magnetized ferrites are derived under some assumptions. The results obtained from this theory indicate that low-field losses are absent if\omega_{M}/\omega\leq\sqrt{5/3}. The theory is in good agreement with experimental results.
Abstract The < 1·0 µm fractions of three rhyolitic tephras are shown to contain multifaceted squat cylinders of halloysite at various stages of development. The < 1·0 µm fraction of one of the tephras, the Pahoia Tuff, is composed mainly of large well-ordered squat cylinders, together with amorphous silica flake…
Two fuel failure mechanisms were identified for coated particle fuels that are directly related to fuel kernel stoichiometry. These mechanisms are thermal migration of the kernel through the coating layers and chemical interaction between rare-earth fission products and the silicon carbide (SiC) layer (the primary bar…
A theoretical study of optical surface plasmon modes of metal spheres is made within the framework of a free-electron spatially dispersive dielectric function model which includes retardation effects. Dispersion equations for homogeneous and inhomogeneous spheres are derived for the lth spherical harmonic. The radiati…
SUMMARYThe phragmosporous genera Magnaporthe and Telimenella are placed in the Physosporellaceae. Ceratosphaeria grisea is transferred to Magnaporthe and Telimenella phacidioidea is newly described. The differences between Hyponectria and Physalospora, both amerosporous genera of the family, are clarified. The species…
Single crystal magnetostriction and thermal expansion measurements are reported on Tb.27Dy.73Fe2. A spin reorientation at T = 283K causes the sudden onset of a very large magnetostrictive distortion which yields a huge anomalous contribution to the linear thermal expansion. The temperature and magnitude of this contri…
Abstract The thermal behavior of films of amorphous silk fibroin in the random‐coil conformation has been investigated in the temperature range 25–220°C by differential scanning calorimetry (DSC), thermal expansion, dynamic mechanical measurements, x‐ray diffraction, and infrared spectroscopy. As the temperature is ra…
The fission product 110mAg released from coated particles can be the dominant source of radioactivity from the core of a high-temperature reactor in the early stages of the reactor life and possibly limits the accessibility of primary circuit components. It can be shown that silver is retained in oxide fuel by a diffu…
The system zirconia‐scandia was investigated using X‐ray diffraction analysis, differential thermal analysis, metallographic analysis, and melting point studies. Results reveal the monoclinic α 1 phase (0 to 2 mol% Sc 2 O 3 ), the tetragonal α 2 ’phase (5 to 8% Sc 2 O 3 ), the rhombohedral β phase (9 to 13% Sc 2 O 3 )…
Experimental evidence is presented indicating that there are two distinctly different kinds of smectic C to smectic A transitions. The first type is second order with zero tilt in both phases, the second type is first order with a non-zero tilt angle in both phases. The model for the second type of transition is an “u…
The effects of various additive elements on the magnetic properties of Sm-Co-Cu-Fe quaternary alloys were studied. It was found that zirconium was the best additive element for improvement of their magnetic properties. The best properties were so far obtained for an alloy of Co, 25.5wt% Sm, 8wt% Cu, 15wt% Fe, 1.5wt% Z…
The properties of pyrolytic silicon carbide (SiC) that are important to its use in nuclear fuel particle coatings are reviewed. The structure of material deposited under different conditions varies in growth features and the constituent phases; the principal effects of neutron irradiation on the structure are to creat…
Abstract Hydroxy-aluminium beidellites are prepared by treating Na-saturated beidellites from Taiwan, with compositions intermediate between end-member beidellite and end-member montmorillonite, with hydroxy-aluminium solutions having OH/Al ratios mainly between 2·00 and 2·50. Chemical analyses show that hydroxy-alumi…
In this review paper, the physico–chemical properties of various dielectric films used on semiconductor devices are compared according to their method of formation or deposition. The insulators which are discussed are silicon dioxide, phosphosilicate glass, silicon nitride, alumina, borosilicate glass, and other silic…
Cuando hace algunos meses, nuestro común amigo Francisco Arredondo me propuso que diese una conferencia en COLCEM-76 sobre los problemas del cemento desde el punto de vista del usuario, acepté complacido, primeramente, por el honor que supone la distinción de elegirme a mí como conferenciante ante Vds., y en segundo l…
Para considerar el grado y la influencia que en los últimos años la industria española ha tenido en el equipamiento del sector de la industria del cemento en Iberoamérica, es conveniente antes situar y definir, aunque sea en grandes trazos, en primer lugar la exportación española de bienes de equipo y maquinaria, y de…