Materials Literature
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Abstract The glass transition, rubbery modulus, and tensile behavior of poly(n‐butyl acrylate)/polystyrene interpenetrating polymer networks (IPN's), semi‐1 IPN's, and their corresponding random copolymer networks were studied as a function of both composition ratio and crosslink density. Two temperatures were selecte…
Abstract The sand and silt fractions of soils derived from Tertiary basalt in northeastern Ireland exhibit unusually high cation-exchange capacities. Smectite was identified by X-ray powder diffraction in all size fractions and was selectively dissolved by treatment with 1 N HCl and 0.5 N NaOH. Structural formulae, ba…
The influence of boundary conditions on the smectic A-C * phase transition has been studied. From a consideration of the free energy under the anchoring condition with planar orientation of moelcules on two boundaries, it is shown that the phase transition temperature from the smectic-A to smectic-C phases decreases w…
The siliceous valve of Hantzschia is briefly described, preparatory to following its morphogenesis. While Hantzschia is morphologically very different to Pinnularia, there are several subtle but important similarities in detail. Bundles of microfilaments, significant in generating the gliding motion of these cells, li…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectronic structure of metalloporphyrins. 1. Experimental electron density distribution of (meso-tetraphenylporphinato)cobalt(II)Edwin D. StevensCite this: J. Am. Chem. Soc. 1981, 103, 17, 5087–5095Publication Date (Print):August 1, 1981Publication History Published online1…
Magnetic field dependences of the first and the second uniaxial magnetocrystalline anisotropy constants K u1 and K u2 for hcp Co were obtained at various temperatures between 4.2 and 616 K by using the 90-points least mean square routine. It was found that the contribution of the Fermi level-dependent term to d K u1 /…
Abstract In Anlehnung an eine phänomenologische thermokinetische Fluktuationstheorie des Glasübergans wird ein Ansatz zur Beschreibung des Einfriervorgangs und von Nachwirkungserscheinungen im Rahmen der linearen Reaktion vorgestellt. Anhand der Auswertung von Thermogrammen \documentclass{article}\pagestyle{empty}\beg…
Abstract The release of norethindrone from a poly(ortho ester) derived from 3,9‐bis(methylene)2,4,8,10‐tetraoxaspiro[5,5] undecane and 1,6‐hexanediol was studied. Thin circular devices containing incorporated drug and a water soluble salt, such as sodium carbonate, sodium sulfate, or sodium chloride, were placed in wa…
The theory of inelastic electron tunnelling spectroscopy (IETS) and the suitability of this technique for examining adhesive-aluminium oxide interfaces are discussed. IET spectra are presented of an epoxide resin (the diglycidyl ether of bisphenol A), two aliphatic amine hardeners (di-[1 -aminopropyl-3-ethoxy] ether a…
Transport and phosphorylation of glucose via enzymes II-A/II-B and II-BGlc of the phosphoenolpyruvate:sugar phosphotransferase system are tightly coupled in Salmonella typhimurium. Mutant strains (pts) that lack the phosphorylating proteins of this system, enzyme I and HPr, are unable to transport or to grow on glucos…
Cathodic electrochromism of lutetium diphthalocyanine films on insulating substrates was investigated by a moving‐boundary technique. Reduction occurred by injection of electrons from a gold contact and cations from a liquid electrolyte. Light blue products formed with aqueous or organic solutions of alkali metal salt…
X-ray and neutron scattering techniques have been used to investigate the spin Peierl's transition in $N$-methyl-$N$-ethyl-morpholinium bistetracyanoquinodimethane [MEM ${(\mathrm{TCNQ})}_{2}$]. Both techniques reveal a doubling of the $c$-axis stacking of the TCNQ molecules below the transition. Diffuse x-ray scatter…
(1981). Mixed Valency Chemistry: A Survey of 10 Years Progress. International Reviews in Physical Chemistry: Vol. 1, No. 2, pp. 149-193.
Abstract Structural models for glasses of the TeO 2 –MoO 3 system are suggested. On the basis of X‐ray and infrared spectral investigations, by comparing with known crystalline structures of TeO 2 , MoO 3 and Te 2 MoO 7 (T 2 M), it is shown that the glasses from TeO 2 to Te 2 MoO 7 possess [TeO 4 ] and [MoO 5 ] groups…
Quantitative results for the correlation functions for the Lorentz model of overlapping hard spheres are worked out and discussed within the recently proposed theory of diffusion and localization of a classical particle moving in a random static field. The applicability of the theory to the diffusion phase is establis…
We have shown that the silk fibroin gene from Bombyx mori is faithfully transcribed in an in vitro transcription system of the HeLa cell extract prepared by the method of Manley et al. [Manley, J. L., Fire, A., Cano, A., Sharp, P. A. & Gefter, M. L. (1980) Proc. Natl. Acad. Sci. USA 77, 3855-3859]. Using this system a…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMultinuclear nuclear magnetic resonance study of three aqueous lanthanide shift reagents: complexes with EDTA and axially symmetric macrocyclic polyamino polyacetate ligandsCharles C. Bryden, Charles N. Reilley, and Jean F. DesreuxCite this: Anal. Chem. 1981, 53, 9, 1418–142…
Abstract A series of segmented polyurethanes based on a hydroxyl terminated polybutadiene soft segment (HTPBD) have been prepared with varying hard segment content between 20 and 60 weight percent. These materials are linear and amorphous and have no potential for hydrogen bonding between the “hard” and “soft” segment…
Scanning electron microscopy and electron probe micro‐analysis were used to investigate the microstructure of both slow‐cooled and quenched polycrystalline BaTiO 3 specimens with a small excess of TiO 2 (Ba/Ti=0.995 to 0.999) or of BaO (Ba/Ti=1.002 and 1.005). The electron micrographs of polished and etched TiO 2 ‐exc…
Abstract Two closely related series of polyesters that contain mesogenic units interconnected by flexible spacers along the main chain were prepared and characterized for their liquid crystal properties. All of these polymers showed theotropic behavior, which was examined by DSC, hot‐stage microscopy on a polarizing m…