Materials Literature
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A binary system of parallel hard spherocylinders and hard spheres are considered to examine influence of addition of spherical molecules to the pure system of rod-like molecules, especially the influence on the structure of the smectic-A phase. Free energy of the system is calculated through the second virial approxim…
Magnetic Fe3C and α-Fe ultrafine particles were prepared by laser-induced pyrolysis of Fe(CO)5 and C2H4. It is found that after passivation, the Fe3C particles exhibit a high saturation magnetization of 132 emu/g compared to that of the α-Fe particle, 95 emu/g. By determining the oxygen content and the present states…
An iterative algorithm is developed for calculating nonlinear optical polarizabilities using a series of generalized sum rules that resemble the Lanczos algorithm and connect spectral moments of the driven single-electron density matrix to ground state charge distributions and bonding network. The size scaling and sat…
Theoretical calculations in combination with experiments for the ${\mathrm{\ensuremath{\pi}}}^{\mathrm{*}}$ and ${\mathrm{\ensuremath{\sigma}}}^{\mathrm{*}}$ x-ray absorption edges are reported for graphite. Theory and experiment agree well for the leading ${\mathrm{\ensuremath{\pi}}}^{\mathrm{*}}$ and ${\mathrm{\ensu…
The excess free energy of small molecules in the amorphous polymers poly(ethylene) and poly(dimethylsiloxane) was calculated, using the test-particle-insertion method. The method was applied to polymer configurations obtained from molecular dynamics simulations with differently prepared initial guess configurations. I…
We report the presence of charge-density waves (CDW's) in the planar square lattices of the layered compounds ${\mathrm{LaTe}}_{2\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Sb}}_{\mathit{x}}$ for 0\ensuremath{\leqslant}x\ensuremath{\leqslant}1, which we have studied through electron microprobe analysis, powder- and s…
We present results of a Monte Carlo simulation of a dense blend, comprising two incompatible homopolymers and a symmetric diblock copolymer, all of the same degree of polymerization. The simulations, in the framework of the bond fluctuation model, yield information on the phase diagram. At high temperatures the copoly…
The spectral behavior and the temperature dependence of the absorption coefficient of microporous silicon films are studied in the energy range of 1.2–3.8 eV, between 7 and 450 K. For photon energies above the direct band gap at 3.3 eV, the spectral behavior of the absorption coefficient is similar to that of crystall…
We studied the size dependence of the ferroelectric domain structure in unique free-standing ${\mathrm{PbTiO}}_{3}$ thin film, composed of grains 60--1000 nm in size, with transmission-electron microscopy. With such samples, we showed that the apparent dependence of electrical properties on the thickness of polycrysta…
Optical spectra of a single crystal of ${\mathrm{La}}_{1.67}$${\mathrm{Sr}}_{0.33}$${\mathrm{NiO}}_{4}$, which undergoes a charge-ordering transition at ${\mathit{T}}_{\mathrm{CO}}$\ensuremath{\sim}240 K, have been investigated for wide ranges of photon energy (0.008--3 eV) and temperature (10--480 K). The opening of…
A brief survey of the electrical and optical properties of poled polymer electrets for sensors and photonic applications is given. Semicrystalline ferroelectric polymers are highly suitable for piezo- and pyroelectric applications, while amorphous polymers containing molecular dipoles with acceptor and donor groups li…
The interaction of screw dislocations with an applied stress is studied using atomistic simulations in conjunction with a continuum treatment of the role played by the far field boundary condition. A finite cell of atoms is used to consider the response of dislocations to an applied stress and this introduces an addit…
Cohesive zone models provide an illuminating and tractable way to include constitutive nonlinearity into continuum models of defects. Powerful insights have been gained by studying both dislocations and cracks using such analyses. Recent work has shown that as a result of the locality assumption present in such cohesi…
In the present paper, the dielectric behaviour of the PbLixNb3xZr0.51Ti0.49-4xO3 ( PLNZT) system is analyzed. It is shown that the decrease in the dielectric constant with respect to an increase of the impurity content may be due to an aggregation trend of the interacting off-centre dipoles rather than due to cooperat…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTA Practical Method for Epoxidation of Terminal Olefins with 30% Hydrogen Peroxide under Halide-Free ConditionsKazuhiko Sato, Masao Aoki, Masami Ogawa, Tadashi Hashimoto, and Ryoji NoyoriView Author Information Department of Chemistry and Molecular Chirality Research Unit, Nagoy…
A kind of nano-amorphous thin film was prepared by RF sputtering. The results of XRD and HREM analysis showed that the film was mainly composed of nano-amorphous particles sized about 10 nm on average. The electrical conductivity was measured using an AC impedance technique in the temperature range 283 - 373 K. It was…
Previously, we discussed a purely classical model for analysing surface plasmons of the molecule. The molecule was described as an abrupt spherical shell containing an effective number of or electrons. This simple model was found to be quite applicable for analysis of electron energy loss spectra (EELS), describing th…
We used electrochemical impedance spectroscopy (EIS) to investigate microbial degradation of polyimides used as insulators in electronic packaging. The microbial inoculum was a fungal consortium isolated from degraded polyimides. Microorganisms grew on these polymers yielding distinctive EIS spectra indicative of fail…
A recently developed electro-optical Pockels effect technique, which allows the dynamic measurement of surface charge distributions, is employed to observe the dynamic behaviour of a partial discharge in a point - dielectric gap. One period of an 8 kV ac voltage is applied to a needle electrode with gap spacings rangi…
We have investigated the partial discharge (PD) due to electrical treeing degradation in low-density polyethylene (LDPE), ethylene - vinyl acetate copolymer (EVA) and ethylene - acrylic acid copolymer (EAA) by a computer-aided partial discharge measurement system which allowed us to obtain phase-resolved PD pulse data…