Materials Literature
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Abstract Solutions of o‐hydroxy or o‐methoxy azobenzene and phenylazonaphthalenes were studied spectroscopically and photochemically in a wide range of temperatures and solvents. All the hydroxy derivatives exist in solution in the azo form, except for (I) and (IV) which show an equilibrium between the azo and hydrazo…
Polycrystalline samples, thin single crystals, and—325 mesh powders of brucite decomposed according to a first‐order rate equation consistent with a random nucleation process in beds of micron‐sized particles formed by disruption during the very early stages of the process and consistent with electron and optical micr…
Abstract A method is presented to crystallize polycarbonate of bisphenol A under constant vapor pressure of solvents at near ambient temperatures. Methylene chloride and acetone were used as crystallizing liquids. Acetone is more powerful in inducing crystallization but the final degree of crystallinity does not depen…
Abstract A procedure for determining the equilibrium shape of a dislocation under the influence of both internal and external stress fields is described. The method, which is an extension of that used by Brown to determine the shape of extended nodes, does not require the explicit numerical integration of line integra…
The performance of electroluminescent layers deposited between double insulating films is described. The dependence of emission properties on and film thickness and Mn content are outlined. The relatively bright (700 ft‐L) and efficient (1 lpw) emission is interpreted in terms of excursions from equilibrium trap occup…
Abstract The Laves phases ZrFe 2 (MgCu 2 type) and TiFe 2 (MgZn 2 type) have a homogeneity range of several atomic percent (mainly on the side rich in iron). An investigation is made of the modifications to this type of AB 2 lattice which result from an excess of B‐atoms. X‐ray and neutron diffraction measurements sho…
Electrochemical studies, as well as microscope observations, on an Fe‐24% Cr alloy in have shown that at least two distinct, potential‐dependent films are formed. The primary film, which is responsible for the initial passivation, is stable only within a few millivolts of the primary activation potential. A secondary…
The diffusion of various liquids in natural rubber vulcanizates has been studied by following the kinetics of the mass uptake of a sheet of rubber while immersed in the liquid. An anomaly in the mass uptake-time relation is due to the stresses set up in the sheet during swelling and to their variation as the swelling…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA Study of the Energy Levels in Benzene and Some Fluorobenzenes by Photoelectron SpectroscopyI. D. Clark and D. C. FrostCite this: J. Am. Chem. Soc. 1967, 89, 2, 244–247Publication Date (Print):January 1, 1967Publication History Published online1 May 2002Published inissue 1…
Raman and infrared spectra have been measured of solutions of oxides of metals of Groups VIA, VA, and IVA in aqueous hydrofluoric, hydrochloric, and perchloric acids. Evidence was obtained for the existence in such solutions of fluoro- and chloro-complexes of molybdenum and tungsten with cis-dioxo-ligands, of mono-oxo…
The crystal structure of MAg4I5(M = K, Rb, NH4) is cubic with a= 11.2 Å, z= 4 and space group of the enantiomorphic pair P4132 and P4332. The locations of the I– and M+ ions have been deduced from symmetry and packing considerations. The Ag+ ions do not occupy distinct single sites, but are distributed randomly over a…
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