Materials Literature
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To analyze the inhibited densification during sintering and differential shrinkage during cooling of Al 2 O 3 /ZrO 2 symmetric and asymmetric laminates, viscoelastic formulations, in which the viscosity and elastic modulus vary with time, have been developed. The viscoelastic mismatch stresses have been numerically co…
Vanadium-containing silicate MCM-41 (V-MCM-41) zeolite and aluminophosphate AFI (VAPO-5) zeolite were synthesized and characterized by spectroscopic techniques. In as-synthesized form, the vanadyl ions (V IV O) 2+ were found to be the major vanadium species in the form of atomic dispersion on AFI by EPR and to exist s…
The evaporation rate of sessile drops of water resting on poly(methyl methacrylate) polymer has been studied by using the recently published precise data of Rowan, Newton, and McHale. Mathematical expressions for an ellipsoidal cap drop resting on a solid surface having three parameters (base radius, height, and conta…
Abstract The micropore volumes of 2 montmorillonites (SAz-1 and SWy-1), each exchanged with Ca, Na, K, Cs and tetramethylammonium (TMA) ions, were calculated from the measured vapor adsorption data of N 2 and neo -hexane by use of t - and α s -plots. The corresponding surface areas of the exchanged clays were determin…
Final‐stage sintering has been investigated in ultrahigh‐purity Al 2 O 3 and Al 2 O 3 that has been doped individually with 1000 ppm of yttrium and 1000 ppm of lanthanum. In the undoped and doped materials, the dominant densification mechanism is consistent with grain‐boundary diffusion. Doping with yttrium and lantha…
The results of self-consistent field (SCF) nonlocal density functional molecular orbital calculations are presented for the various spin states and tautomeric forms of a cobalt complex with two o -quinone-derived ligands. In addition, new variable-temperature solution magnetic susceptibility, EPR, and electronic absor…
The long-term confusing glass transition temperature, T g, and specific heat capacity, Δ C p, of the 4,4‘-diisocyanatodiphenylmethane (MDI) and 1,4-butanediol (BD) hard segment in segment polyurethanes have been clearly evidenced by using a new series of completely phase-mixed polyurethanes while being extrapolated to…
The calorimetric titration of H 3 PW 12 O 40 (H 3 PW) with a series of bases in CH 3 CN gives equilibrium constants and enthalpies for the three deprotonation steps. These results show that solutions of H 3 PW in any solvent whose basicity is equal to or weaker than CH 3 CN will only furnish one strong proton per mole…
We studied the dependence of the dynamic properties on the generation G of a star-burst dendrimer model. The Rouse approximation for the mobility matrix was used for simplicity. We categorized all normal-mode displacements and considered various time-dependent correlation functions and the intrinsic viscosity. We dete…
Optical switching behavior of low-molecular-weight and polymer azobenzene liquid crystals (LCs) was explored by means of reflection-mode analysis. Reflectivity changed on pulse irradiation under various conditions of orientations of LC molecules with respect to incident probe light, either s-polarization or p-polariza…
▪ Abstract Recent progress in the field of mechanical behavior of layered ceramics is reviewed. Several processing techniques are described with reference to the fabrication of ceramic laminates. These include tape-casting, centrifugal casting, slip-casting, electrophoretic deposition (EPD), and the production of fibr…
Three metal complexes of one particular homochiral porphyrin were investigated as catalysts for enantioselective epoxidation of unfunctionalized olefins under various reaction conditions. Much better results were obtained with the iron and ruthenium complexes than with the manganese derivative. The absence of any effe…
The crystal structure of [Pt(trpy)(MeCN)](SbF 6 ) 2, where trpy denotes 2,2‘:6‘,2‘‘-terpyridine, shows that the platinum complex packs as a monomer; however, the 3 π−π* emission of the solid occurs at surprisingly long wavelengths at room temperature. At lower temperatures new, shorter-wavelength maxima appear. Of the…
The stress‐rupture properties of precracked minicomposites were determined in air at temperatures in the range of 700°‐1200°C. The minicomposite systems consisted of a single tow of Nicalon or Hi‐Nicalon fibers with carbon or boron nitride (BN) interphases and a chemical‐vapor‐infiltrated silicon carbide (CVI‐SiC) mat…
The cspD gene of Escherichia coli encodes a protein of high sequence similarity with the cold shock protein CspA, but cspD expression is not induced by cold shock. In this study, we analyzed the regulation of cspD gene expression. By using a cspD-lacZ fusion and primer extension analysis, the expression of cspD was fo…
Abstract A genetic algorithm (GA) based method for solving crystal structures directly from powder diffraction data has been developed. The method is based around fitting the diffraction data generated from trial structures against the measured diffraction data and has the ability to handle flexible molecules and mult…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTDendrimers Containing Organometallic Moieties Electronically CommunicatedIsabel Cuadrado, Carmen M. Casado, Beatriz Alonso, Moisés Morán, José Losada, and Vitaly BelskyView Author Information Departamento de Química Inorgánica, Universidad Autónoma de Madrid, 28049-Mad…
We examine the influence of attractive interactions on the phase behavior of rodlike colloids. We model the rodlike particles by spherocylinders, for which the phase diagram, in the absence of attraction, is known for arbitrary aspect ratio. We consider the case that the attraction is due to depletion forces caused by…
Crystal structures of ( E )-azobenzene (1), ( E )-2,2′- dimethylazobenzene (2), ( E )-3,3′-dimethylazobenzene (3) and ( E )-4,4′-dimethylazobenzene (4) were determined by X-ray diffraction at various temperatures. An apparent shrinkage of the N=N bond and its temperature dependence were observed and are interpreted in…
Low-water content reverse micelles have been formed in cyclohexane employing Triton X-100 or AOT (bis(2-ethylhexyl) sulfosuccinate sodium (salt) as the surfactant. Steady-state and time-resolved luminescence quenching studies, using Ru(bpy) 3 2+ as the luminophore and Fe(CN) 6 3 - or MV 2+ as the quencher, have shown…