Materials Literature
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Calculations of the vibrational density of states and the Raman and infrared spectra have been performed for random-network, microcrystalline, and polymorph structures of Si and Ge. The polymorphs considered include Si III, Ge III, and two clathrate structures. The calculations are based on simple semiempirical forms…
When hexagonal boron nitride is exposed to ionizing radiation two types of paramagnetic centers appear: three-boron centers and one-boron centers. Results of electron paramagnetic resonance, thermoluminescence, and thermally-stimulated-current measurements associated with these centers are described, and a model is pr…
Light and electron microscopic examinations have been made on a number of species previously attributed to the genus Amphipleura Kütz. As a result, two groups of species can be delimited, both of which warrant generic status. The genus Berkeleya Greville is therefore extended to include the marine tube-dwelling specie…
The discharge space between a positive cylindrical electrode (in the diameter range 0.3185-3.175 cm) and a coaxial outer electrode of diameter 58.1 cm has been irradiated by a radioactive beta -source to obtain a stable glow discharge in which streamers are absent. Onset electric gradient, voltage-current characterist…
Proteins taken directly from the Bombyx mori silk gland have been separated and identified as either fibroin or sericin on the basis of their location within the gland and their amino acid composition. Molecular weights of these polypeptides have been determined by sodium dodecyl sulfate polyacrylamide gel electrophor…
Abstract The diffusion of water vapour through samples of cured and uncured fleece and fibreglass wool was measured. The diffusion resistance of the fibreglass was close to the value expected for still air, i.e. 4.2 s cm-1 per centimetre for samples ranging in depth from 1 to 7 cm. The resistance for natural fleece wa…
Ultrafine particles of Ni${\mathrm{Fe}}_{2}$${\mathrm{O}}_{4}$ coated with organic molecules show a behavior consistent with extremely strong pinning of the ferrite surface spins. The low-temperature magnetization is only \ensuremath{\sim}75% saturated in fields of 200 kOe, and M\"ossbauer spectra show that the spins…
The inorganic crystalline polymer polysulfur nitride has been found to become superconducting with a transition temperature of (0.26\ifmmode\pm\else\textpm\fi{}0.03)\ifmmode^\circ\else\textdegree\fi{}K.
Resistivity measurements on crystals of ${({\mathrm{V}}_{0.99}{\mathrm{Cr}}_{0.01})}_{2}$${\mathrm{O}}_{3}$ grown by vapor transport confirm our earlier results. They do not support the reinterpretation of metal-insulator transition given by Honig, Chandrashekhar, and Sinha in a recent Letter.
An analytical model has been developed to simulate the thermal NOx emission processes in various gas turbine combustors for a variety of fuels. The NOx emissions predicted by the model are in excellent agreement with available laboratory and field data. Its capability to simulate the water injection process accurately…
When the nematic phase of MBBA is rapidly cooled by exposure to liquid nitrogen a glassy solid is formed which, X-ray diffraction studies indicate, has the nematic ordering quenchedin. The sequence of events which occur upon reheating this glass was monitored using X-ray diffraction and a differential thermal techniqu…
The alkali centrifuge technique has been extensively studied in relation to maturity, and the results have shown that it is a simple, fast, and highly reproducible test method for determining the maturity of cotton fibers either in the raw state or after soxhelet extraction to remove waxes, provided there is no damage…
The recovery of fabrics from bending strains is basically the property which determines whether the fabric will be wrinkle-free and is thus an important factor in the total concept of ease-of-care. The capacity of a fabric to recover from a bending strain depends on a number of physical properties of the single filame…
Plutonium and uranium nitrides have been synthesized by reacting a solution of the actinide iodide and a solution of sodium, potassium, or calcium in anhydrous liquid ammonia. The precipitate was identified by elemental analysis, infrared absorption, and x-ray diffraction. Nitrides are of interest as fast breeder reac…
Abstract Nickel-base superalloy (713LC) powders produced by two techniques have been consolidated by a single-stage, hot isostatic pressing operation to obtain fully dense, coarse-grained (ASTM 1-2) material. After heat treatment the compacts produced by powder from the rotating electrode process gave tensile strength…
Alignment inversion walls in nematic liquid crystal layers deformed by an electric field have been observed. Different types of walls in layers with planar boundary conditions could be distinguished. Beginning at some irregularity, the walls split into pairs of disclination lines. The speed of the splitting depends li…
Mössbauer experiment has been performed in TbFe 1- x Cr x O 3 . Hyperfine field at 57 Fe nuclei is 550 kOe at 0 K for x =0, and it decreases by 9 kOe when one Fe 3+ ion is replaced by a Cr 3+ ion at the nearest neighbor site of 57 Fe 3+ ion. This decrease is attributed to the change in the supertransferred hyperfine i…
Summary Wroewolfeite is a new mineral from the Loudville lead mine in Loudville, Massachusetts, U.S.A. The mineral occurs as blue, monoclinic crystals, twinned on {001}, very similar in appearance to posnjakite and langite. It is formed as small isolated pinacoidal crystals (up to 1.0 mm) implanted on covelline and ch…
A method for determining the acoustic properties of thin plates is described. Existing theoretical expressions are used to calculate transmission and reflection coefficients for sound waves striking the plates at arbitrary angles of incidence. Theory is substantiated by experimental data, and refined values for absorp…
The relative efficiencies of phosphorus and sulfur-based flame-retardant systems have been compared on cotton, ramie, and rayon. Sulfur-based systems were found to be equally effective on all the substrates tested. Phosphorus-based flame retardants were significantly less effective on rayon than on cotton or ramie. Th…