Materials Literature
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Abstract The effects of diluent on molecular motions and glass transition in the polystyrene–toluene system was studied by means of dielectric, thermal, and NMR measurements. Three dielectric relaxations were observed between 80 and 400°K. On the basis of NMR measurements on solutions in toluene and in deuterated tolu…
By using the 0-lattice formalism of Bollmann, Burgers vectors of intercrystalline boundary dislocations are defined from the knowledge of two near-coincident cells M1 and M2 of lattices 1 and 2. Internal points belonging to M1 and M2 are taken into account to construct the DSC lattices related to the given boundary. A…
Abstract The structural changes in poly(vinyl chloride) during thermal degradation in nitrogen at 190°C have been investigated. From gel permeation chromatography analyses no chain scission, but only crosslinking reactions were observed. An increase in the molecular weight was measured even at 0.3% conversion. For lon…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFactors influencing the stabilities of nematic liquid crystalsMichael J. S. Dewar and Robert M. RiddleCite this: J. Am. Chem. Soc. 1975, 97, 23, 6658–6662Publication Date (Print):November 1, 1975Publication History Published online1 May 2002Published inissue 1 November 1975h…
Domain wall kinetics are studied in glassy iron-base wire and iron-nickel–base ribbon. These materials exhibit high wall mobilities. The wire is examined in a single-wall regime below the nucleation field. Here reversal takes place by propagation of a domain wall of 2.5-cm axial length along the wire. The mobility nor…
The distribution of the nuclei of chromium hexacarbonyl Cr(CO)6 in the crystalline state was refined from neutron diffraction data at 78K. It was found that diffraction by the aluminum walls of the cryostat used for low-temperature measurements was superimposed on the diffraction peaks of the crystal, and a method was…
A comprehensive perturbation formalism is developed in order to relate the rotating-frame spin-lattice relaxation time ${T}_{1\ensuremath{\rho}}$ to the relative motions of the nuclear spins in a crystal lattice. A general relaxation equation valid in the entire temperature region is derived, from which both the stron…
Fourteen year data for 90-10 and 70-30 cupronickel alloys exposed in sea water at the F. L. LaQue Corrosion Laboratory, Wrightsville Beach, North Carolina are reported. Corrosion rates for both alloys in quiet and flowing as well as in the tidal zone tended to become linear after the first 4 years' exposure. Initially…
The refractive index and the absorption coefficient for sputtered α-HgS films several μm thick were determined in the wavelength region from 0.5 to 2.5 μm by the analysis of transmission and reflection spectra. The results showed that the refractive index for as-deposited films decreased with increasing rf power densi…
Abstract Coarse, medium, and fine‐textured soils were studied in three different arid regions of Iran, namely Gazvin, Karaj, and Kooshkak alluvial plains, respectively. Six representative pedons including 33 samples were tested. X‐ray analyses indicated the clay mineral components of soils consist of some discrete ver…
Abstract Thick Bh horizons in siliceous sands of the North Carolina Coastal Plain have essentially no extractable iron, and very small quantities of calcium, magnesium, and potassium. Aluminum is the dominant cation and the exchange properties of the Bh horizons are dominated by Al and organic carbon. One to two grams…
The phase-Q structures of Na0.98K0.02NbO3 and Na0.90K0.10NbO3 have been determined at room temperature by the neutron powder profile refinement technique. Two different models were refined: orthorhombic, space group P21ma (No. 26, in cab setting) and monoclinic, space group Pm (No. 6, in the second setting). The latte…
The introduction of a phenomenological relaxation time to take collision into account in the longitudinal dielectric formulation raises some questions of principle. The author attempts to elucidate the method adopted to deal with these questions, presents a complete derivation of the RPA dielectric function by this me…
Conditions leading to surface brightening during ECM in passivating electrolytes were investigated by studying high rate transpassive nickel dissolution in acidified nitrate electrolytes under controlled hydrodynamic conditions. The experimental apparatus consisted of a flow channel cell in which constant electrolyte…
The MINDO/3 SCF MO method has been used to investigate the equilibrium geometries, electronic structure and ground state properties of ttf and tcnq and their uni- and di-valent ions. An analysis of the results indicates that both ttf+ and tcnq- have low energies of disproportionation and that electron addition or remo…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCircularly polarized luminescence and energy transfer studies on carboxylic acid complexes of europium(III) and terbium(III) in solutionChun Ka Luk and F. S. RichardsonCite this: J. Am. Chem. Soc. 1975, 97, 23, 6666–6675Publication Date (Print):November 1, 1975Publication Hi…
Abstract Des mesures de RPE sur la lacune d'oxygène ayant piégé un électron (centre F + ) dans ZnO, and permis de déterminer les paramètres des interactions hyperfines magnétique et quadrupolaire électrique, avec un noyau Zn 67 adjacent à la lacune. Ceci dans les deux cas possibles de configuration: celui qui correspo…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOxygen binding to iron porphyrinsJames P. Collman, John I. Brauman, and Kenneth S. SuslickCite this: J. Am. Chem. Soc. 1975, 97, 24, 7185–7186Publication Date (Print):November 1, 1975Publication History Published online1 May 2002Published inissue 1 November 1975https://pubs.…
Symmetry rules are derived for relating the convergent-beam electron-diffraction pattern symmetries to the three-dimensional symmetry of the structure. These rules are applied to a study of 2M biotite. As a result the space group is determined as C2, or number 5 in International Tables for X-ray Crystallography, where…
Abstract β-K4SiW12O40·9H2O is orthorhombic, with the space group Pnma and a=20.62(1), b=15.57(1), c=12.95(1) Å, Dm=4.88 g cm−3 and Dx=5.04 g cm−3 for Z=4. The crystal contains a discrete β-SiW12O404− polyanion, a geometrical isomer of the α-SiW12O404− with the well known Keggin structure. The idealized Keggin ion has…