Materials Literature
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Abstract An experimental study has been made of recrystallization processes which have been initiated at grain boundaries in aluminium samples. The samples had an initial grain size of between 30 and 130 μm and were deformed 50 % by rolling before annealing at 573 K. The microstructures developed in the region of the…
We have studied, using computer simulation techniques, the properties of edge and screw dislocations in an amorphous Lennard-Jones solid. We find the edge dislocation to be unstable and the screw to be stable. The elastic properties of the screw dislocation in the amorphous solid are like those in a crystal.
The habit of crystals grown from highly supersaturated solution has been formed to be governed by linkages of coordination polyhedra from a morphological analysis on the basis of crystal structure. Such a vector of linkages having a direction and an energetical period which represents the three dimensional structure m…
A discrete, calcareous layer that binds the foliated calcite of the oyster's shell to the organic ligament in the hinge is reported, apparently for the first time. This layer is ultrastructurally, and generally mineralogically, different from the underlying foliated calcite, and is named the ligostracum.
Abstract Small angle X‐ray scattering measurements were made on samples of polycarbonate (PC) and poly(methyl methacrylate) (PMMA) containing crazes. A sharp, well pronounced maximum in the scattering intensity was observed in the direction perpendicular to the draw direction. The distribution of scattered intensity a…
This Letter investigates the phonon scattering in Si${\mathrm{O}}_{2}$ glass at frequencies above 100 GHz by phonon spectroscopy with superconducting tunnel junctions. By analyzing the frequencies of the scattered phonons with two independent techniques, evidence is obtained for strong inelastic phonon scattering in g…
This Letter represents a theory of transport in random metal alloys which focuses on certain model-independent features of the electron-phonon dynamics which have been previously neglected. It is found that the adiabatic phonon approximation breaks down in the high-resistivity regime producing an anomalous negative te…
Article Verfeinerung der Kristallstruktur des Silberperchlorats AgClO4 was published on November 1, 1979 in the journal Zeitschrift für Kristallographie - Crystalline Materials (volume 149, issue 1-4).
It has long been known that thin films of cholesteric liquid crystals subject to a shear will exhibit a blue shift in the color that they reflect. In this article a molecular structure that could explain this shift is postulated. Using Mauguin’s continuum model of a cholesteric liquid crystal, the governing electromag…
Abstract Les spectres vibrationnels des phases Na 4 SnO 4 , Na 4 PbO 4 et K 4 SnO 4 ont été étudiés pour la première fois. Ils caractérisent des groupements tétraédriques XO 4 isolés. Les attributions des fréquences IR et Raman ont été effectuées par analyse du groupe facteur. Les constantes de forces, calculées à par…
Abstract Hot stretching experiments for an atactic polystyrene have been performed in the temperature range 125 to 180°C, at various elongation rates and with different times of application of the orienting field. Mechanical properties of the oriented samples, including Young's modulus, yield strain and stress, ultima…
The measurements of magnetostriction and anisotropy of r.f. sputtered amorphous Gd1−xCox thin films are reported. Both were measured in the range of composition x=0.667–0.835 using cantilever-capacitance method. The perpendicular anisotropy Ku and saturation magnetostriction λs reach extremal values in the vicinity of…
L-Fucose dehydrogenase [EC 1.1.1.122] was isolated from a rabbit liver extract and purified about 390-fold with a yield of approximately 13%. The purification procedures included treatment with protamine, ammonium sulfate fractionation, treatment with acid, DE-32 celluose colum chromatography, gel filtration on Sephad…
Abstract Tetrachlorothallates MTlCl 4 (M=K, Rb and NH 4 ) crystallizing in the tetragonal CaWO 4 type were obtained by crystallization from highly concentrated aqueous TlCl 3 solutions containing small amounts of MCI. The structural parameters of NH 4 TlCl 4 were determined from single-crystal data. The indates MInCL…
X‐ray diffraction measurements were used to determine the equilibrium phases for Na 2 O·y(Al 1 ‐ x Fe x ) 2 O 3 _ m in air for values of x from 0.05 to 0.6 and values of y from 2.5 to 9. The β“ ‐alumina structure was the only single phase observed. At 1400°C, the β” single‐phase region extends for 3.5< y < 7.5 a…
The discharge capacity of a porous iron electrode is controlled by either the extent of interparticle neck growth achieved during sintering or the amount of surface area retained following sintering. The mode of capacity control is related to the density of the electrode.
Thermal stability criteria capable of explaining Thoma's observations that bias-induced reversible switching transitions in inhomogeneous thin insulating and semiconducting films occur at a critical value of local power density are developed and analyzed. One model, based on a relation between the temperature and heat…
The aberration theory of diffraction gratings has been studied by means of geometric optics. No restrictions are imposed on the form of the grating surface, the pattern of the grooves in the grating surface, and the position of the object. Furthermore, the image plane is not limited to one normal to the principal ray.…
Abstract Stereoselective syntheses of the two optically active pheromones of ants, (+)-(E)-4,6-dimethyl-4-octen-3-one (manicone) and (+)-(E)-2,4-dimethyl-2-hexenoic acid, and of β-sinensal and (E)-β-farnesene are described in which allylic thiolcarbamates readily derived from allylic alcohols via the [3,3]sigmatropic…
Second order transitions are discussed for compounds of the heavy rare earths and yttrium with cobalt. The calculated Curie temperatures agree well with those observed and an analogy is established between the effect of rare earth additions and of pressure. First order transitions in critical fields and at critical te…