Materials Literature
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The D - E hysteresis loop of ferroelectrics is theoretically studied on the basis of the extended Avrami theory. If the sideway velocity depends only on the instant value of the applied field, the volume fraction of the reversed area is expressed as q ( E )=1-exp (- f - d Φ( E )), where f and d are, respectively, the…
A blue-photoluminescence (PL) band, centered at 2.6 eV, was observed in thermally and chemically oxidized light-emitting porous silicon layers with an efficiency that can exceed 0.1%. The PL decay is found to be independent of excitation intensity and detection wavelength, and to be nonexponential with a characteristi…
We report a dielectric anomaly in several perovskites at intermediate frequencies 10\ensuremath{\le}f\ensuremath{\le}${10}^{7}$ Hz in the temperature range 400 \ifmmode^\circ\else\textdegree\fi{}C \ensuremath{\le}T\ensuremath{\le}800 \ifmmode^\circ\else\textdegree\fi{}C. We have found this dielectric maximum in more t…
Abstract Three new types of fillers for polypropylene are investigated. The first two were derived from burnt rice husk ash (RHA), whereas the third, a wood‐based filler, was processed from oil palm trunk. One important characterization of the composites involves the checking for the actual filler content and filler d…
Abstract Reactive liquid polymers (RLP), carboxyl‐terminated butadiene–acrylonitrile copolymers (CTBN), epoxy‐terminated butadiene–acrylonitrile copolymers (ETBN), amine‐terminated butadiene–acrylonitrile copolymers (ATBN) of different molecular weights (from 2200 to 6500 g/mol), and a nonfunctional butadiene–acryloni…
Diffraction approaches suggest that some quasicrystal structures can be described as hierarchical packing of atomic clusters. When treated as spherical potentials, these clusters may contain ``magic numbers'' of electrons which allow exact filling of the electronic shells of the hierarchy of wells. Physical propeties…
Abstract Polyimide resists developable with basic aqueous solutions were realized by polyamic acid esters with phenol moieties (PPh's) and naphthoquinone diazides. The polyimide precursors (PPh's) were synthesized from diamines and dicarboxylic acids that have phenol moieties through ester linkage. A selective reactio…
Indium oxide (In2O3) thin films doped with either germanium or silicon were prepared by using a radio-frequency magnetron sputtering method. The target was the In2O3 powder mixed with either Ge or Si powder. The resistivities of the films were compared with that of the film doped with tin (ITO). The Ge and Si dopings…
We have studied focused electron beam induced deposition from W(CO)6 at beam primary energies between 20 and 0.06 keV. Submicrometer resolution with 4 nA beam current was maintained at very low primary energies using a retarding field configuration. Decomposition cross sections of W(CO)6 for primary energies below abo…
We report the vapor phase growth of partially filled graphitic fibers, 20-30 nm in diameter and up to a micron in length, during a manganese catalyzed carbon electric arc discharge. The fiber morphology resembles that of catalytic chemical vapor deposited carbon filaments but the inside hollow contains intermittent pr…
The ability to control structural dimensions below 5 nm is essential for a systematic study of the optical and electrical properties of Si nanostructures. A combination of electron beam lithography, NF3 reactive ion etching, and dry thermal oxidation has been successfully implemented to yield 2-nm-wide Si nanowires wi…
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” opt…
Abstract The effect of the molecular weight and acrylonitrile (AN) content of the styrene–acrylonitrile copolymer (SAN) on the morphology, mechanical properties, and rheological properties of acrylonitrile–butadiene–styrene terpolymer/poly(methyl methacrylate) (ABS)/PMMA (60/40 by weight) blends were studied. When the…
Indium oxide films with an electrical resistivity of less than 1.5×10−4 Ω cm and good optical quality were prepared by the reactive ion plating of pure indium in an oxygen atmosphere of ∼10−4 Torr. The deposition rate was in the range of 500–900 Å/min, which is much higher than that of the ordinary evaporation. Hall e…
Crystal-field parameters (B k,m ) were obtained for LaOBr doped with Tm 3+ from the analysis of luminescence spectra. The crystal-field Hamiltonian H CEF = Sigma km B km + Sigma i C km (r i ) for the C 4v symmetry comprises five non-zero B k,m parameters. The results of model crystal-field calculations in C 4v symmetr…
Infrared transmission of 25 liquid crystal compounds was evaluated. Based on these results, a liquid crystal mixture consisting of fluoro and dialkyl diphenyl-diacetylene homologs was developed for CO2 laser application. This mixture exhibits a wide nematic range, high birefringence, low viscoelastic coefficient, and…
Ag(111) and Ag(110) surfaces exposed to oxygen at elevated temperatures (\ensuremath{\sim}800 K) exhibit strongly enhanced Raman bands at 803 and 627 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ which are attributed to O atoms strongly chemisorbed on the surface (${\mathrm{O}}_{\ensuremath{\gamma}}$) or held in subsurfa…
A thin bilayer of two coexisting polymer phases, in contact with a surface which favors and is partially wetted by one of them, was studied by nuclear reaction analysis and phase contrast microscopy. We find that when the less-favored phase is initially in contact with this surface, it is entirely replaced by the part…
We report experimental investigation and theoretical interpretation of the formation of sprial waves in a nematic liquid crystal subjected to a rotating magnetic field and a high frequency electrical field.
A unified model of phonon-assisted and zero-phonon radiative transitions in nanoscale silicon structures is presented. For characteristic sizes above 15--20 \AA{}, phonon-assisted transitions dominate, while zero-phonon transitions, allowed due to the finite-size effect, are more important for smaller length scales. L…