Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTheoretical Young's moduli of poly(p-phenylenebenzobisthiazole) and poly(p-phenylenebenzobisoxazole)Kohji Tashiro and Masamichi KobayashiCite this: Macromolecules 1991, 24, 12, 3706–3708Publication Date (Print):June 1, 1991Publication History Published online1 May 2002Publis…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPressure-volume-temperature properties and equations of state in polymer blends: characteristic parameters in polystyrene/poly(vinyl methyl ether) mixturesT. Ougizawa, G. T. Dee, and D. J. WalshCite this: Macromolecules 1991, 24, 13, 3834–3837Publication Date (Print):June 1,…
Abstract The association behavior of protoporphyrin IX was investigated at different pH by absorption spectroscopy and gel chromatography. Protoporphyrin IX existed as monomer in acidic water, as aggregate in neutral water, and as dimer in basic water. Poly(N-vinylpyrrolidone) tended to suppress dimerization and aggre…
In this paper, we systematically develop a hierarchy of constitutive equations at various levels of abstraction for describing the dynamics of incompressible liquid-crystalline systems. We also introduce a corresponding hierarchy of generalized bracket formulations. The simplest brackets, in terms of the direction vec…
AIN powder was synthesized from aluminum polynuclear complexes. Basic aluminum chloride and basic aluminum lactate were used as the aluminum polynuclear complexes. These starting materials and glucose were dissolved in water and mixed homogeneously. AIN powder was obtained by calcining after drying and precalcining at…
L'etude structurale des complexes du cuivre montre qu'il n'y a pas de difference geometrique importante dans les cages Cu 2 (COO) 4 entre les cuivre acetate et cuivre formiate. Les populations electroniques des groupes carboxylate des coordinats pontants sont correlees avec les valeurs −25 des carboxylate des complexe…
Abstract Oedometer swelling and compaction tests up to a maximum pressure of 32 bars were made on the Wyoming montmorillonite SWy-1 with a range of mixed (Na,K) exchange ion compositions. The permeabilities and water diffusivities of the compacted clays were calculated using soil physics theory. Significant inhibition…
The effect of surface charge on the impulse flashover of short spacers in SF/sub 6/ was investigated. A split-electrode arrangement allowed scanning of the entire space surface by a capacitive probe. With a heterocharge distribution which facilitates both inception and propagation of the discharge, the flashover level…
Abstract Lower Palaeozoic shales and slates in the External Domain of the southern Canadian Appalachians are composed predominantly of illite and chlorite with minor occurrences of I-S mixed-layer minerals (restricted to samples with illite crystallinity, IC > 0·62°Δ2 Θ ) and paragonite (restricted to samples with…
The influence of defects on the apparent phase transition temperature has been studied over a large range of defect concentrations. An interval was found for low concentrations (around 1 mol%) in which the transition temperature depends only weakly on the number of defects and where defect tails occur. This interval i…
N-Acetylneuraminate lyase produced by Escherichia coli was purified and crystallized from a genetically engineered strain (E. coli SF8/pNAL1). The enzyme showed apparent molecular masses of 105,000 Da on gel filtration and 35,000 Da on SDS/PAGE, suggesting that the enzyme is a trimer. The apparent optimum pH and tempe…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTComparative study of polyoxometalates and semiconductor metal oxides as catalysts. Photochemical oxidative degradation of thioethersR. Carlisle Chambers and Craig L. HillCite this: Inorg. Chem. 1991, 30, 13, 2776–2781Publication Date (Print):June 1, 1991Publication History P…
Yttria‐doped tetragonal zirconia containing 2 and 3 mol% Y 2 O 3 (Y‐TZP), and CeO 2 ‐doped Y‐TZP containing 0 to 12 mol% CeO 2 were sintered at 1350°C in a tetragonal single‐phase field for 2 h in air, and the degradation behavior at low temperature in air and in hot water was observed. X‐ray photoelectron spectroscop…
Pulsed laser deposition in ultrahigh vacuum (UHV) was applied to the epitaxial growth of CeO 2 film on Si(001). Although the direct deposition of CeO 2 (001) on Si(001) was unsuccessful, the desired epitaxy was achieved by inserting the growth of a SrTiO 3 layer. The formation of a CeO 2 (001)//SrTiO 3 (001)//Si(001)…
Synopsis Some previously unreported fine variations in the form of normal hairs are described as they are observed in the scanning electron microscope (SEM). They all arise in the course of surface frictional wear and the chipping away of the hair surface scale edges and include remanent surface impressions of cuticle…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCrystal and molecular structure of 21-thia-5,20-diphenyl-10,15-bis(p-nitrophenyl)-porphyrin and 21,23-dithiatetraphenylporphyrin. The influence of sulfur on the .pi.-delocalization patternLechoslaw Latos-Grazynski, Jerzy Lisowski, Ludmila Szterenberg, Marilyn M. Olmstead, an…
A synthesis of theories for the orientational entropy and excluded volume interaction for persistent chain polymers at intermediate degrees of chain flexibility, when extended to liquidlike densities, is shown to satisfactorily account for experimental data on the volume fractions of polymer at coexistence of isotropi…
Eleven samples from a range of volcanic ash soils (Andisols or Andic Dystro-chrepts) and one sample from a paddy soil formed in alluvium (Inceptisol) have been investigated for the presence of ferrihydrite using dissolution analysis and differential X-ray diffraction (DXRD). The presence of ferrihydrite in six samples…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRemarkable solvent effect on the shape-selective oxidation of olefins catalyzed by iron(III) porphyrinsYoshihito Watanabe, Kazuya Yamaguchi, Isao Morishima, Katsuomi Takehira, Masao Shimizu, Takashi Hayakawa, and Hideo OritaCite this: Inorg. Chem. 1991, 30, 12, 2581–2582Publ…
It has been found that the reaction rate between alumina and carbon in nitrogen can be considerably increased by using Al(OH)3–C mixtures instead of α Al2O3–C mixtures. The C/Al(OH)3 ratio in the starting mixtures should be greater than the stoichiometric ratio to complete the reaction. It was observed that alumina is…