Materials Literature
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We report extensive density functional theory calculations, using pseudopotentials with a plane-wave basis, for the properties of the (010) face of molybdenum trioxide (α-MoO3). The surface is modeled by a one-layer slab. Calculated bond lengths compare favorably with experimental measurements. The bonding of the diff…
It is shown that total reflection for all incident angles does not require a two- or three-dimensional photonic crystal. We demonstrate that a one-dimensional photonic crystal can exhibit total omni-directional reflection for any incident wave within some frequency region. The formation of the omni-directional gap is…
The molecularly dispersed V 2 O 5 /SiO 2 supported oxides were prepared by the incipient wetness impregnation of 2-propanol solutions of V-isopropoxide. The experimental maximum dispersion of surface vanadium oxide species on SiO 2 was achieved at ∼12 wt % V 2 O 5 (∼2.6 V atoms/nm 2 ). The surface structures of the mo…
Some secondary or β relaxations in glass-forming materials involve molecular motions that bear strong resemblance to the primitive α relaxations of the coupling model, although the two are not identical. For these β relaxations, at the glass transition temperature Tg the relaxation time τβ(Tg) is expected to be shorte…
X-ray photoelectron spectroscopy was used for surface characterization of amorphous Cu−M alloy powders (Cu 40 Ti 60, Cu 50 Zr 50, and Cu 65 Hf 35 ) produced by mechanical alloying of the constituents. When used as catalyst in the dehydrogenation of alcohols Cu−Zr and Cu−Hf were found to undergo structural changes resu…
Thermally stimulated depolarization current thermograms were obtained from modelling experiments on polar systems, assuming that the polarization can be described by a weighted summation of elementary Debye-like processes. The analysed situations were studied both by global and by cleaned experiments and the features…
Not all Schottky groups of Mobius transformations are classical Schottky groups. In this paper we show that all Fuchsian Schottky groups are classical Schottky groups, but not necessarily on the same set of generators. AMS Classification 20H10; 30F35, 30F40
Pure and chromium-substituted lithium ferrites have been made in air by self-propagating high-temperature synthesis (SHS), a combustion process involving the reaction of lithium peroxide, iron oxide, chromium oxide and iron or chromium metal powders. Three series of SHS samples were produced: by SHS only; by SHS follo…
Contributions to the first-order rate constant for the decay of the Eu 3+ ( 5 D 0 ) state of tris(2,2,6,6-tetramethyl-3,5-heptanedionato)europium(III), Eu(thd) 3, from radiative and multiphonon mechanisms are evaluated independently by measuring the luminescence decay rates in undeuterated Eu(thd) 3, fully deuterated…
As part of a survey on the influence of fused aromatic rings on the porphyrin chromophore, a series of novel structures with fused acenaphthylene or benzothiadiazole rings have been synthesized. Base-catalyzed condensation of 1-nitroacenaphthylene or 4-nitrobenzothiadiazole with esters of isocyanoacetic acid afforded…
The laser express technique has been applied to high temperature measurements of CVD diamond reflectivity R and absorption coefficient (alpha) for radiation with 1.06 mm wavelength as well as heat capacity. It was found that at T > 1000 degrees C and heating cycles of a few seconds the sample surface layer with thi…
The response to an external applied static electric field of a large spherical sample of a lattice of dielectric spheres embedded in a dielectric medium is analysed. The lattice cells are simple cubic and contain one dielectric sphere per cell. The response gives a dielectric constant for the lattice array. The electr…
A Raman spectrometer designed for the purpose of in-situ diagnostics of materials deposited in a gas discharge plasma under conditions of intense illumination from the discharge and heat radiation from a substrate is described. The characteristic feature of the spectrometer is the use of a pulsed Cu-vapor laser as the…
Two versions of the decoupling approximation (DA) are used to study the isotropic—nematic phase transition of hard ellipse systems. The results of the scaling procedure with respect to hard discs and the scaling with respect to the isotropic phase of hard ellipses are compared with the corresponding Monte Carlo simula…
The synthesis of side-chain liquid crystalline polyacetylenes containing phenyl benzoate mesogens with octyl spacers and cyano ( 2a ) or methoxy tails ( 2b ) is accomplished, and the tuning of the molecular alignments of 2b is realized by simple mechanical perturbations. The acetylene monomers, 10-[4-(4‘-R-phenoxycarb…
The results of isothermal—isobaric Monte Carlo (MC-NPT) simulations for N = 1020 hard spherocylinders of aspect ratio L/D = 5 with embedded central longitudinal point dipoles are presented. The effect of the dipolar interactions on the phase transitions to the mesophases is examined. For this aspect ratio, non-polar h…
A new series of hydrotalcite (HT)-like anionic clays containing Zr 4+ in the brucite-like layer has been synthesized by a simple coprecipitation method at constant pH. The incorporation of Zr in the layer has been investigated by various analytical methods, such as powder X-ray diffraction (PXRD), chemical analysis, F…
The coordination of substituted pyridines to MTO (methyltrioxorhenium) is governed by both electronic and steric effects. For example, the binding constant of pyridine to MTO is 200 L mol - 1, whereas that of the better donor 4-picoline is 730 L mol - 1 and that of the sterically encumbered 2,6-di- tert -butyl-4-methy…
A novel scheme for using modified colloidal crystals as templates for silica polymerization is reported. 3D close-packed crystals of submicrometer latex spheres are assembled on a membrane surface by filtration. To induce silica polymerization, the particles are modified by adsorption of the surfactant hexadecyltrimet…
By ab initio LMTO calculations in atomic-sphere approximation we have studied the interlayer exchange coupling between Fe films separated by Au spacers in infinite Fe/Au multilayers with (001) interface orientation. We also performed detailed calculations of the magnetization and charge profiles across the system. We…