Materials Literature
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The solutions of the pseudo 1-dimensional compound Li 2 Mo 6 Se 6 in N -methyl-formamide (NMF) previously obtained by Tarascon, Di Salvo et al. are shown to be of a liquid crystalline nature. A lyotropic nematic phase is observed within the concentration range (4 ·10 −2 ÷ 10 −1 ) mol/l Li 2 Mo 6 Se 6 /NMF. The gel pha…
Enzymes deposited on solid support usually show good stability when operated in organic solvents. Decreased stability of the enzyme preparations was noticed when low enzyme loadings were used (e.g., with Celite as support; less than 1 mg enzyme/g). It was possible to avoid the activity loss by the addition of an addit…
Binary mixtures of suspended, nearly hard-sphere, sterically stabilized colloidal silica particles of diameter ratio 6 were observed to phase-separate at comparable volume fractions of the two particle species. The occurrence of phase separation as a function of the particle concentrations was studied visually and by…
Abstract The effects of copper, mercury, nickel, zinc, cadmium, indium, magnesium, and calcium stearates on the course of N ‐cyclohexyl‐2‐benzthiazylsulphenamide‐accelerated sulfur vulcanization of natural rubber have been investigated on the basis of curemeter measurements at 145°C. The differences in the efficiencie…
(Ba,Ca)TiO3 samples with the ratio of (Ba+Ca) to Ti as unity but prepared by (i) a semiwet route involving (Ba,Ca)CO3 solid solution precursors and TiO2 and (ii) the conventional dry route involving BaCO3, CaCO3, and TiO2 powders, exhibit diffuse and BaTiO3-type sharp ferroelectric phase transitions, respectively. Rie…
Surface segregation in thin films of symmetric polyolefin diblock copolymers containing a lamellar microstructure, cast on a variety of substrates, has been investigated. In all cases, the conformationally smaller block preferentially segregated to both the solid and air interfaces even though the surface energy of th…
FexCu1−x (x = 0.50 to 0.75) nano-multilayers are prepared by alternate deposition of pure Fe and Cu metals. The multilayers were then irradiated by xenon ions and annealed in situ in transmission electron microscopy, respectively, to investigate the possibility of the metastable phase formation. A new metastable phase…
Some results of the research on electrical (electrical conductivity and thermoelectric power) and electrochemical properties of monocrystalline pure vanadium dioxide and tungsten-doped WxVO2 oxide (x = 0.010, 0.018, 0.022, and 0.025) are presented. A strict correlation between the electronic and electrochemical proper…
Conduction studies are carried out on Eu2O3 thin film capacitors. From the ac conduction studies the dielectric constant is found to decrease with increase of frequency (< 1 MHz), but at very high frequency (> 1 MHz) it is found to increase. The ac conductance is found to be proportional to f at low frequencies, where…
Aurivillius phases are compounds with the general formula (Am−1BmO3m+1)2− (Bi2O2)2+ that consist of (m − 1) perovskite-like units interrupted by bismuth oxide layers. Compounds with A = {Ba2+; Sr2+}, B = {Nb5+}, and m = 2 are studied by EXAFS spectroscopy and X-ray diffraction. The lattice parameters a and c of the te…
A new phosphor in the system K2SO4 Na2SO4 doped with Eu is reported. This is shown to be at least thrice as sensitive as the conventional CaSO4: Dy phosphor used in the thermoluminescence dosimetry of ionizing radiations. Characterization of this phosphor using XRD, PL, and TL techniques is described.
The increase in photoluminescence and thermoluminescence of CaSO4: Dy TLD phosphor by co-doping with Ce or P is described. Cerium is found to sensitize the PL but not the TL. P doping helps incorporation of Dy in higher concentration. PL increases by 150% while the increase in TL is about 50%. It is claimed that the C…
Many experimental works report that the presence of water trees lowers the voltage needed for the initiation of dielectric breakdown in polyethylene. The influence of water trees on the dielectric breakdown is generally related to their length. Here, in addition to this spatial property, we consider the extinction of…
The negative-ion fractions of oxygen directly recoiled from a Ni{100}c(2\ifmmode\times\else\texttimes\fi{}2)-O and a NiO{100} surface have been measured as a function of the crystal azimuthal angle and the recoiled atom exit trajectory from the surface. The data exhibit a pronounced angular dependence of the ion fract…
Crystal structure of LiNH 4 SO 4 was refined in phase II (room temperature) and phase III (190 K) by the use of X-ray diffraction intensity with including hydrogen atoms. The least-squares calculations converged with residual parameter R =0.0362 and 0.0378 for phases II and III, respectively. At room temperature, ther…
We have developed a theory of photoemission from III-V compound semiconductors within the one-step model and discuss the effect of transition-matrix elements, final states, and the surface barrier on the energy distribution of photoelectrons. As a prototype the (110) surface of GaAs is studied, and theoretical spectra…
The processes of formation and crystallization of thin films of SrTiO3 prepared by the method of metallo-organic decomposition have been studied with particular emphasis on the relationship between the thermal decomposition of the metallo-organic precursors and the eventual epitaxial alignment of the crystallized film…
The interpretation of the infrared and Raman spectra of polyconjugated polyfuran prepared by electroreduction of 2,5-dibromofuran is presented as the result of lattice dynamical calculations. Geometries and vibrational force fields are derived from semiempirical calculations carried out on oligomers and the parameters…
Abstract Graft polymerization of anionic and cationic monomers was performed onto the surface of poly(ethylene terephthalate) (PET) film with a simultaneous UV irradiation method, but using no photo‐sensitizer. To effect graft polymerization, the PET film was immersed in an aqueous solution containing a monomer and pe…
Schottky barrier formation of metal contacts deposited on diamond (111) and (100) surfaces was investigated. Three different metals (Au, Al, and Ti) were studied because of their different chemical reactivity with C, i.e., Au being a nonreactive metal, Al a weak carbide-forming metal, and Ti a strong carbide former. B…