Materials Literature
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The absorption spectrum of Ti3+:Al2O3 crystals grown in a reducing atmosphere consists of the main blue-green absorption band and a weak infrared band. This infrared absorption decreases in intensity on annealing the as-grown samples in a reducing atmosphere. The analysis of electron spin resonance spectra of the as-g…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThin silver films: influence of substrate and postdeposition treatment on morphology and optical propertiesShane E. Roark and Kathy L. RowlenCite this: Anal. Chem. 1994, 66, 2, 261–270Publication Date (Print):January 15, 1994Publication History Published online1 May 2002Publ…
The dielectric constant and ac conductivity of rf-sputtered insulating zinc oxide films has been measured in the metal-insulator-metal configuration over a wide temperature (90--500 K) and frequency (0.1--100 KHz) range. The films sputtered from oxide targets in argon were c-axis oriented having a resistivity of \ensu…
The transitional properties of the liquid crystal dimers formed by two mesogenic groups linked by a flexible chain exhibit a pronounced dependence on the number of atoms in the spacer. Here we present the results of a theoretical calculation of the nematic–isotropic transition temperature, the entropy of transition, a…
We report the dependence of the microwave-frequency dielectric constant and dc conductivity on the crystallinity and local order of doped polyaniline. The dramatic increase of the dielectric response in the three highest crystalline physically crosslinked polyaniline samples provides evidence for the formation of thre…
We present a study of the electrical transport in porous Si layers prepared by anodic etching of two different kinds of (100) p-type Si substrates. It is shown that by choosing a sufficiently thick layer, the problem of injection from the contacts can be eliminated. In this way we measure the intrinsic transport prope…
Cathodoluminescence has been investigated in diamond films, prepared by microwave plasma assisted chemical-vapor deposition. Results are presented for various diamond films differing in crystalline structure and doping. In the energy range 2.0--2.7 eV a series of 13 sharp luminescence lines has been observed at temper…
A general and practical model for heat generation that can be used in the heat conduction equation for nonisothermal semiconductor device simulations is presented. The model is developed for cubic semiconductors with position-dependent, multivalley, and multiband band structures, Fermi-Dirac statistics and an accurate…
Abstract When 4,4'‐bis (3,4‐dicyanophenoxy) biphenyl is heated with small amounts of aromatic amine or amidine salts, a highly crosslinked polytriazine is obtained. This polymer has been shown to be the same as that reported when bisphthalonitriles are heated with amines. Salts promote this reaction more readily and t…
Photoemission and bremsstrahlung isochromat spectra have been measured on TiO 2 (rutile) and SrTiO 3 . The magnitudes of the fundamental band gaps estimated from the combined spectra agree well with the results of the photoabsorption and the energy-band calculations. The profiles of the observed spectra do not reveal…
The pair correlation functions g(r) of liquid water obtained at pressures of up to 7.7 kbar at a constant temperature of 20 °C are discussed. A variety of evidence of the very strong effect of pressure on the structure of liquid water has been found. In particular, an unusual pressure dependence of the shortest interm…
Optical properties have been studied in amorphous thin films of various Ge-based chalcogenide glasses with a view to investigating the effect of Te isovalence substitution in the Ge-S-Se system. Te either completely replaces S to give Ge 2.5 Te 2.5 Se 95 and Ge 5 Te 5 Se 90 or partially replaces Se to give Ge 2.5 S 2.…
Free-radical side-chain brominations of alkylaromatics in supercritical carbon dioxide (SC-CO(2)) are reported. Direct bromination of toluene and ethylbenzene form the corresponding benzyl bromides in high yield. The observed selectivity in SC-CO(2) is similar to that observed in conventional organic solvents. Also, S…
This paper reviews recent developments in highly magnetostrictive terbium-dysprosium-iron alloys. This includes discussion of domain structure, the magnetization process, microstructure, sample preparation, magnetostriction, effects of different chemical compositions on magnetic properties of the alloys, and possible…
The F1-ATPase from Bacillus PS3 (TF1) hydrolyzes 50 microM ATP in three kinetic phases. An initial burst rapidly decelerates to a partially inhibited, intermediate phase, which, in turn, gradually accelerates to an uninhibited, final steady-state rate. Lauryl dimethylamine oxide (LDAO) stimulates the final rate over 4…
The folding of the small protein barstar, which is the intracellular inhibitor to barnase in Bacillus amyloliquefaciens, has been studied by equilibrium unfolding methods. Barstar is shown to exist in two conformations: the A form, which exists at pH values lower than 4, and the N state, which exists at pH values abov…
The structure of RP 71955, a new tricyclic 21 amino acid peptide active against human immunodeficiency virus 1, was determined. Its amino acid composition was inferred from the results of fast atom bombardment mass spectrometry, nuclear magnetic resonance, Raman spectroscopy, and amino acid analysis. Its sequence coul…
Abstract In the present study, the dose‐rate effects of γ‐irradiation in air on two isotactic polypropylene grades of different molecular weight distribution, used for medical devices, were investigated. The thermal, mechanical, rheological, and photometric properties of these materials were examined using DSC, stress…
This paper deals with the application of simulated annealing to rock magnetism. The implementation of the algorithm is discussed in detail. It is shown that the technique can be used to determine stable micromagnetic structures by finding very low energy states which are not easily found using other optimization techn…
Abstract This article presents crystallization kinetics studies on a cocrystallizing polymer highdensity polyethylene (HDPE)/linear lowd‐ensity polyethylene (LLDPE) blend. The nonisothermal crystallization exotherms obtained by differential scanning calorimetry (DSC) were analyzed to investigate the effect of cocrysta…