Materials Literature
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A commercial sintered silicon nitride has been crept in bending and compression at temperatures of 1100°C to 1400°C. In the as‐sintered condition the material contains an amorphous intergranular phase. This phase undergoes partial devitrification as a result of high temperature exposure. Preannealing the material to a…
The antiferroelectric smectic-${\mathit{C}}^{\mathrm{*}}$ (Sm-${\mathit{C}}^{\mathrm{*}}$) phases of two closely related chiral compounds have been studied with high-resolution calorimetric techniques. Both methylheptyloxycarbonylphenyl octyloxybiphenyl carboxylate (MHPOBC) and its octylcarbonylbiphenyl analog (MHPOCB…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSensitivities of droplet size and stability in monomeric emulsionsKevin Fontenot and F. Joseph SchorkCite this: Ind. Eng. Chem. Res. 1993, 32, 2, 373–385Publication Date (Print):February 1, 1993Publication History Published online1 May 2002Published inissue 1 February 1993ht…
With magnesium present, fluoride and aluminum ions activate heterotrimeric G-proteins by forming AlFx complexes that mimic the gamma phosphate of a GTP. We report compelling evidence for a newly proposed process of G-protein activation by fluoride and magnesium, without Al3+. With millimolar Mg2+ and F-, Gs and Gt act…
The way to polymeric copper phosphides is probably marked by multinuclear Cu clusters accessible from copper chloride and functionalized phosphanes. One of the multitude of new compounds with unusual structures prepared from these starting materials is [Cu12(PPh)6(PPh3)6], whose central CuP framework is shown here.
The driving force for surface reconstruction is shown to be given by the (usually nonzero) difference between the surface energy and stress, leading to a ground state characterized by an isotropic stress tensor with vanishing shear components. The analytic results, illustrated by atomistic simulations of the missing r…
Small amplitude oscillatory shear has been used to study thermotropic liquid-crystalline polymers that have mesogenic groups pendant to flexible backbones. The polymers studied form nematic and smectic glasses, enabling viscoelastic response to be studied over a wide range of frequencies using time-temperature superpo…
Brownian dynamics simulations were used to study the adhesion of hard spheres on a solid surface by taking the hydrodynamic interactions into account. Special attention was paid to analyze the configuration of the assembly of adsorbed particles. These results were compared to configurations generated by the extensivel…
Abstract Angle‐resolved XPS data from two well‐characterized samples of SiO 2 on Si were analyzed using three different algorithms for the determination of overlayer thickness. The relative ratio algorithm, the Heaviside step function approximation to the Laplace transform algorithm and the absolute ratio algorithm we…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructural characterization of verdoheme analogs. Iron complexes of octaethyloxoporphyrinAlan L. Balch, Lechoslaw Latos-Grazynski, Bruce C. Noll, Marilyn M. Olmstead, Ludmila Szterenberg, and Nasser SafariCite this: J. Am. Chem. Soc. 1993, 115, 4, 1422–1429Publication Date (…
Polymeric materials and their composites have been employed in a variety of medical and surgical applications, such as tissue replacement and support. In the case of biodegradable polymers, primary areas of application include sutures, macroscopic implants for fixation, and drug release systems [1-4].
The crystal structure of the Al3Mn phase, considered to be closely related to that of decagonal auasicrystais, has been determined by a combination of single-crystal X-ray analysis and high-resolution electron microscopy. The atomic model, obtained from a Patterson synthesis and high-resolution electron microscopy, wa…
Abstract Fluorescence line narrowing (FLN) spectroscopy was used to study the vibrational features of Zn porphyrins, including Zn octaethylporphine, Zn mesoporphyrin, Zn deuteroporphyrin and Zn coproporphyrin, and the interaction of these porphyrins with their solvent matrices. A number of ground‐state vibrational lev…
The second virial coefficient for the surface tension increment of polymer solutions is evaluated for repulsive (Dirichlet) and reflecting (neutral) impenetrable surfaces. Renormalization group theory is used to describe the influence of excluded volume. An interpolation function extends the calculations to intermedia…
Article Effect of Calcining Temperature on Volatilization of Ruthenium in Batch Calcination of Simulated High-Level Liquid Waste was published on February 1, 1993 in the journal Radiochimica Acta (volume 60, issue 2-3).
Defects in lithium vanadate (Li3VO4) exposed to x rays were studied by electron spin resonance (ESR). 77 K irradiation produces two types of trapped-hole centers. One is supposed to be carbonate radical CO3−, which is thermally stable even at room temperature. Another, having a hyperfine interaction with a vanadium nu…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPotassium complexes containing both crown ether and tertiary phosphine oxide ligandsVladimir V. Grushin, Corinne Bensimon, and Howard AlperCite this: Inorg. Chem. 1993, 32, 3, 345–346Publication Date (Print):February 1, 1993Publication History Published online1 May 2002Publi…
Two planktonic species of diatoms, Chaetoceros bacteriastroides and C. seychellarus , have been studied by light and electron microscopy. Important features that may be used as taxonomic characters are described. A new subgenus, Bacteriastroidea, is proposed to include C. bacteriastroides, because of its unique charac…
Six species of Caralluma have been found to occur in Oman: C. adenensis, C. “arabica”, C. flava, C. hexagona, C. penicillata and C. quadrangula, none being endemic to the country. The name C. aucheriana is considered obscure and its application should be discontinued. The application of the name C. arabica is uncertai…
Studies the effect of thread tension and the stitch length, L , as well as the fabric thickness, t , and its compressive modulus, E , on the seam balance and total thread consumption.