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The anisotropy measurement combined with magnetic measurement and electron microscopy is performed on monocrystalline Alnico alloys with various contents of Ti and Co, to examine the effects of these constituents, especially of Ti, upon the high coercivity in Alnico alloys. The shape anisotropy constant, Ku* increases…
The behaviour of interstitial atoms of light elements in the iron lattice are discussed and classified, particularly in regard to their influence on the bonding nature of the iron lattice and their tendency of formation of platelet clusters. According to this general consideration the stress induced clustering of hydr…
A non-linear least squares technique was used to determine k 11, k 33, ε1 and ε2 by comparing data from a single birefringence vs. voltage experiment. Liquid crystal optical cells with parallel orientation were used to generate the birefringence-voltage curve from which the parameters were determined. Cell thickness w…
A topic of intense interest to polymer morphologists in the past few years is the phenomenon variously called row nucleation or oriented crystallization (from a stressed melt) and shish-kebab crystallization (from stirred solutions) [1–4]. The phenomenon can be characterized as the formation of a fibrillike nucleus, p…
Abstract—The cationic polymerization of heterocyclic monomers may lead to polymers containing substantial, yet Variable amounts of cyclic oligomers. This review gives a survey of the systems where such oligomers have been found. Oligomer formation is generally observed in the polymerization of oxiranes and thiiranes.…
The diatom flora of the cavern system of Timpanogos Cave National Monument was investigated. Diatoms were found throughout the cave system and were distributed according to moisture and natural openings. Twenty‐six species were identified and described, including eight not previously collected from caves and four new…
It is shown that the difference in the free energy of activation for atoms diffusing in the lattice and in the grain-boundary is precisely the absolute grain-boundary energy. The self-diffusion data in Au in the lattice and along the grain-boundaries yielded excellent values of grain-boundary energies as a function of…
In order to determine the oxygen coordination numbers of Fe ions in the melts, Mössbauer spectra of Fe ions in silicate and posphate glasses have been measured and the distributions of Fe3+ (tetr.) and Fe3+ (oct.) in CaO-SiO2 or Na2O-SiO2 systems have been calculated. The results indicate that the ratio of Fe3+ (oct.)…
The influence of age and of corticosteroid treatment on viscoelastic properties of skin samples has been studied in rats. Hysteresis curves were evaluated with increased extension for each cycle. Maximum stress and modulus of elasticity were increased by age and by 10 days' prednisolone treatment. However, hysteresis…
Goldschmidt factors taking into account substitution ions are calculated for a series of doped PZT. X-ray measurements in the paraelectric phase are reported. The occurrence of a ferroelectric or of an antiferroelectric phase is related to the tolerance factor and to a hydrostatic stress on the ions in the B position.
It is well known that radiation (both particle and photon) can cause substantial density changes in certain solids. In cases where the radiation damage is non-uniformly distributed, these changes are manifested as gradients of residual stress. With ion bombardment, where penetrations under accelerating voltages of sev…
Crystal structure of sugilite has been refined by the least squares method using 435 reflections measured on an automated single crystal diffractometer using MoKα radiation. The final unweighted R-factor is 0.047 for 429 reflections. The cell dimensions are: a=10.007(2), c=14.000(2)Å; space group P6⁄mcc. Sugilite is i…
Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter Facebook Reddit LinkedIn Tools Icon Tools Reprints and Permissions Cite Icon Cite Search Site Citation Richard Williams; Electrochemical reactions of semiconductors. J. Vac. Sci. Technol. 1 January 19…
Professor Helfrich is the 1976 winner of the Hewlett-Packard Europhysics Prize which is awarded annually for outstanding achievement in solid state physics. The award which is to be presented at the opening of the 19th. Congress Ampre in Heidelberg on 27 Sept., 1976 is for his contributions to the physics of liquid cr…
The crystal structure of a β-hydroquinone clathrate of stoicheiometry 3C6H4(OH)2·xH2S (x= 0.768) has been determined from three-dimensional X-ray data. The hydrogen-bonded [OH]6hexagonal rings are nearly but not exactly planar, and a difference map revealed an ordered proton arrangement. The clathration cavity is roug…
The rate of growth of slightly soluble ionic precipitates from aqueous solution is affected by the presence of a co-ordinated layer of water molecules clustered around a central ion. When the ions are small and highly charged, water molecules in the cluster are firmly held; in such solutions it is known that ion assoc…
Abstract Polystyrenes containing end groups derived from azobisisobutyronitrile (AIBN) were subjected to thermal degradation at 280–350°C and the rates of volatilization compared with those of thermally and anionically prepared polystyrene. At 330–350°C the degradation of the AIBN polymer resembled that of the thermal…
Abstract In the thermal oxidation of low density polyethylene (PE) in the melt phase and isotactic polypropylene (PP) in the solid phase, the changes in molecular weight distribution (MWD), weight average molecular weights ( M ω), and average number of chain scissions have been studied by gel permeation chromatography…
Two homologous series of liquid crystalline substances have been synthesized and their mesomorphic properties studied. These are (i) trans-p-n-alkoxy-α-methyl cinnamic acids and (ii) trans-p-n-alkoxy-α-methyl-p'-cyanophenyl cinnamates. The esters are colourless and fairly low melting materials of high positive dielect…
The ferroelectric-paraelectric phase transition in PbZrxTi1-xO3 (0.88 < x < 1) has been investigated using x-ray, dielectric and optical techniques. It is shown that a changeover from first-order to second-order behaviour occurs at around x = 0.94. The exponent, β, of the order parameter in the region of this critical…