Materials Literature
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The electrical resistivity of near-stoichiometric crystalline V2O5 has been measured as a function of crystal orientation and oxygen partial pressure from 25° to 300°C. Conductivity is insensitive to ambient atmosphere. The activation energy for conduction is 0.20 eV. Molten V2O5, however, is sensitive to oxygen parti…
Abstract A new empirical model has been proposed to described crystallization systems where the growth rate increases with increasing crystal size in violation of McCabe's Δ L law. Experimental data for Glauber's salt have been presented to illustrate the fit of the new model to an actual system. Equations for steady…
When fine powders of vitreous silica, quartz, tridymite, cristobalite, coesite, and stishovite of known particle-size distribution and specific surface area are investigated for their solubility in aqueous suspensions, final concentrations at and below the level of the saturated concentration of molybdate-active silic…
The alkoxy benzoic acids, above n-propyl, exhibit liquid crystal properties. The homologous series of acids from n-propyl to n-octadecyl has been synthesized, the transition temperatures of each member of the series measured by means of a heated-stage, polarizing microscope, and the corresponding transition energies d…
The behaviour of the magnetic properties for the 5T2g term under simultaneous perturbation by spin–orbit coupling and an asymmetric (trigonal or tetragonal) ligand field is presented. The theory is applied to the variation of the magnetic properties of nine Fe(II) octahedral complexes over the temperature range 80–300…
In diffusion-controlled sorptive processes, Fick's second equation can be solved analytically only for special functional forms of an immobilization isotherm. The dissimilarity in the formal appearance of attainable solutions hides common features of physical behaviour. The rate processes can, however, be broadly char…
The structure change of tantalum on heating in air and oxygen was followed by X-ray diffraction. Numerous forms of Ta oxides have been identified. Ta-(O) (solid solution), TaO y , TaO z , δ-form and β-Ta 2 O 5 are formed in air at either atmospheric or reduced pressure. The nitrogen in the air is important for high te…
Stoichiometric crystals of and were grown by slowly cooling solutions of the polycrystalline apatites in fused or . While fluorapatite is hexagonal, optical and x‐ray observations indicate that has a monoclinic space group. All crystals of this compound are highly twinned. At about 200 °C a transition to a hexagonal p…
G. R. Penzer and G. K. Radda, Q. Rev. Chem. Soc., 1967, 21, 43 DOI: 10.1039/QR9672100043
Abstract To calculate the elastic constants, (C ij ), of the polyethylene (PE), Born's dynamical theory of long wave method has been used for a model of interatomic interactions representing inter‐ and intramolecular force fields. Among various types of interaction potentials between nonbonded atoms, two sets of H‐H,…
Abstract Impact strength and damping as functions of temperature have been compared for eight polymers with typical differences in damping behavior, viz., four methacrylate polymers, a polyphenylene oxide, a polycarbonate, a polyoxymethylene, and a rigid polyethylene. If a damping maximum is caused by a movement withi…
Iron foil specimens were anodically polarized by means of a potentiostat in , , and a sodium borate‐boric acid solution ( p H, 8.5). Both passive, active, and transpassive regions of the polarization curve were studied for each solution. The oxide films were examined while still in contact with the iron foil by select…
Abstract Refined expressions, amendable to experimental testing, for the equilibrium elastic strains in epitaxial overgrowths are derived, based on earlier theories by van der Merwe and Cabrera. Continuous films as well as isolated nuclei on substrates are considered.
A study has been made of all the known factors which limit the performance of high resolution (0.07 to 0.01 eV FWHM) monochromators. These limiting factors have been incorporated into design equations for the optimum (maximum current output) monochromator. The conclusions are tested by performance measurements on a pr…
Abstract A study has been conducted of the kinetics of the reaction of ether alcohols, primary and secondary methoxypropanols, with phenyl isocyanate in the presence of metal catalysts. The proximity of the methoxy and methyl groups to the hydroxyls had a significant effect on the reaction rates as did the type and co…
Abstract Die Bereichsstrukturen, die auf der Basisebene eines Kobalteinkristalls auftreten, wurden experimentell und theoretisch untersucht. Die Vielfalt der Erscheinungen läßt sich deuten, wenn man zu den bisher betrachteten Energietermen noch die magnetostriktive Eigenenergie hinzunimmt. Diese Energie beherrscht vor…
Abstract The properties of molecular weight fractions of linear polyethylene, encompassing the range 3 × 10 3 to 1.5 × 10 6 , which were isothermally crystallised at low undercooling at. atmospheric pressure, were studied. Marked changes in various thermodynamic and mechanical properties are observed with molecular we…
Silicon avalanche diodes have been mounted on diamond to achieve a continuous power density more than twice that achieved on copper. A pair of parallel connected wafers oa a single sample of diamond produced 4.7 watts of CW power at 13.3 GHz using a room temperature heat sink.
Abstract
Infrared spectra of pyrazole in the vapour and solid states and in solution are reported and discussed. From these, and by comparison with the spectra of N-deuterio-, 3-methyl-, and 3,5-dimethyl-pyrazole, and other simple five-membered heterocycles, a vibrational assignment is proposed.