Materials Literature
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Abstract The reinforcement of elastomers by carbon black is governed by the morphology of the black and its physical and chemical interactions with the polymer. The latter are strongly affected by graphitization and surface oxidation. In modern rubber-grade carbon blacks strong bonding of the polymer to the carbon bla…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPorphyrins. 36. Synthesis and optical and electronic properties of some ruthenium and osmium octaethylporphyrinsArtemis Antipas, Johann W. Buchler, Martin Gouterman, and Paul D. SmithCite this: J. Am. Chem. Soc. 1978, 100, 10, 3015–3024Publication Date (Print):May 1, 1978Pub…
Glasses in the system Al 2 O 3 ‐Y 2 O 3 ‐SiO 2 , containing TiO 2 and La 2 O 3 , were investigated. Glasses of high refractive index and elastic modulus were developed. The observed Young's and shear moduli of these glasses show good agreement with theoretical values. Agreement was also found between the observed and…
Abstract Fourier transform infrared studies of the thermal degradation of polyacrylonitrile (PAN) conducted at 200°C in air and under reduced pressure are presented. The spectra are markedly superior to those published previously. A mechanism consistent with the infrared results obtained under reduced pressure is adva…
Met-tRNA,, initiator methionyl transfer RNA.SDS, sodium dodecyl sulfate; Gpp(CH,)p, guanyl-5'-yl methylene diphosphonate; App(CHJp, adenyl-5'-yl methylene diphosphonate; EMC, encephalomyocarditis.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPrediction of Changes in Bubble Size Distribution Due to Interbubble Gas Diffusion in FoamRobert LemlichCite this: Ind. Eng. Chem. Fundamen. 1978, 17, 2, 89–93Publication Date (Print):May 1, 1978Publication History Published online1 May 2002Published inissue 1 May 1978https:…
A theory based on two electrons hopping between defect sites recently proposed (Elliott 1977, 1978) to account for the frequency dependence of the conductivity of chalcogenide glasses is analysed here with regard to the predicted temperature dependence. To a first approximation, the logarithm of the a.c. conductivity…
We present evidence that in carbon-polyvinylchloride composites, consisting of aggregates of carbon spheres (100-400 \AA{}) dispersed in the insulating matrix, the electrical conductivity can be ascribed to a novel mechanism of tunneling with potential-barrier modulation by thermal fluctuations. Theoretical considerat…
A systematic compilation of chemical thermodynamic and elementary reaction rate data has been carried out, using information obtained from literature searches and chemical kinetic modeling. These data are presented in a flexible and convenient form for use in computer programs which require such input data.
For pt.I see ibid., vol.11, p.1523 (1978). A set of interionic potentials of the Born-Mayer form is derived for the alkali halides. The specification is completely in terms of parameters of two types, (a) parameters which relate to the constituent ions and (b) parameters which apply to all crystals. Thus the parametri…
Room temperature measurements of the phonon dispersion relations in ferroelectric lithium niobate have been carried out by inelastic neutron scattering. Most of the measurements were made along the c* direction with two acoustic branches measured along an a* direction. The q to 0 slopes of the acoustic branches are fo…
A consistent set of shell parameters for alkali halide crystals of both rocksalt and CsCl structures is reported. The fitting procedure, values of the parameters and their sensitivity are discussed. Short range interionic potentials are determined and are shown to give a good description of both static and dynamic pro…
A study of variations of charging and discharging transients in low-density (0.918 gm cm -3 ) polyethylene has been made over a wide range of fields and temperature and a limited range of sample thickness and electrode materials. In the temperature range 113-273K two broad isochronal (i.e. current at constant time) pe…
A general description is given of the behavior of polymeric dielectrics in low fields, including polarisation and depolarisation, and transient and steady state conduction, in isothermal and non-isothermal conditions. An attempt is made to present a unified interpretation applicable to all of these phenomena.
Measurements are reported on the lateral motion of charges along thin films of polyethylene terephthalate (PET) in air at 40% humidity. A sensitive, high-resolution induction probe coupled to a computer is used to scan the sample in a raster mode. Thus it is possible to produce not only line scans of the charge distri…
Vacancy mutation by (about six) trapped helium atoms — as has been observed in molybdenum — reduces the vacancy concentration, at which interconnecting paths for the helium begin to form, from 16 to 10% in b.c.c. materials. This follows from percolation studies which include this mutation effect.
Structural phase transitions are investigated in crystals of the isostructural compounds MRA2 (M alkali metal, R trivalent metal, A anion (MoO4)2- or (WO4)2-). A group-theoretical analysis of possible transitions is carried out. It is shown that the transitions are of pure ferroelastic nature, occur between centrosymm…
Optical and EPR studies of K(H1−xDx)2PO4 (0⩽x⩽1) single crystals irradiated at 77°K with 60Co gamma rays and observed in liquid nitrogen, argon, and oxygen, have permitted not only the identification of two radical species produced as HPȮ−4 and H2PȮ4, but also a description of the annealing processes and their correla…
Condensation potentials and corresponding electrical currents are observed during the isothermal growth of amorphous, cubic, and hexagonal ice from the vapor phase. Upon heating of the condensate a thermally stimulated current (TSC) spectrum is observed with the application of any external electric field. Current peak…
Metal complexes of water-soluble and other porphyrins have been prepared by a heterogeneous reaction with the metal reactant present in an insoluble form. The oxidation state of the metal is important in the reactions. Metal reactants in the lower oxidation states (0, I, II) react with porphyrins but those in the high…