Materials Literature
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Current peaks due to transient SCLC (space charge limited current) were observed in LDPE (low-density polyethylene) at 70/spl deg/C. From the time at which the current peak occurs, carrier mobilities ranging from 5/spl times/10/sup -15/ to 7/spl times/10/sup -14/ m/sup 2//Vs were obtained. The mobility values obtained…
Nonlinear optical (NLO) properties of transition metal complexes are studied using quantum chemical calculations. By comparison with all electron calculations, effective core potentials have been shown to be competent for the calculation of NLO properties as long as the valence basis sets are comparable. While overall…
FTIR absorbance spectra of SiO 2 glass containing 1200 ppm OH⁻ groups were recorded in situ to 1975 K. There are only minor changes in peak height to 1700 K, indicating that the molar extinction coefficient measured at ambient conditions, at the peak maximum, is applicable for OH⁻ determination at high temperature. Ho…
The Shubnikov--de Haas measurement of the organic superconductor $\ensuremath{\kappa}\ensuremath{-}{(\mathrm{B}\mathrm{E}\mathrm{D}\mathrm{T}\ensuremath{-}\mathrm{T}\mathrm{T}\mathrm{F})}_{2}{\mathrm{Cu}}_{2}(\mathrm{CN}{)}_{3}$ yields a rapid oscillation originating from the calculated two-dimensional Fermi surface.…
Capacitive-resistive field distributions including surface and volume resistivities have been computed in and around HV porcelain and capacitor bushings. The boundary element method has been applied for field computation in two axi-symmetric bushing configurations including four dielectrics. Effects of uniform and non…
A common approach in modeling martensitic phase transitions in the framework of continuum mechanics involves a nonconvex energy. This paper analyzes the influence of the spinodal region, or the region where the energy density is concave, on the resulting equilibria. We compare a one-dimensional model with a degenerate…
The star models are briefly summarized and used to explain the layer thickness of the soluble block of polystyrene-poly(ethylene oxide) (PS−PEO) diblock copolymer micelles in water and cyclopentane. Both the discrete blob model (DB) and the distribution density (DD) model describe well the tethered layer of the solubl…
The experimental detection of a spin reorientation phase transition by means of Fe $K$-edge x-ray magnetic circular dichroism (XMCD) is reported for ${\mathrm{Nd}}_{2}{\mathrm{Fe}}_{14}\mathrm{B}$. The temperature dependence of the XMCD signals at both Fe ($K$ edge) and Nd (${L}_{2,3}$ edges) is compared to that of th…
By the protection of the carboxyl group of 3-thiopheneacetic acid with differently substituted benzyl groups a series of new thiophene derivatives were synthesized. While 3-thiopheneacetic acid is not electropolymerizable, the new obtained monomers can be easily electrooxidized to form stable electroactive polymers. T…
Core yams are known to improve cotton yam properties. In this research, core yarns are spun by introducing filaments under tension into the yarn-forming zone of an ex perimental friction spinning apparatus. A 30-denier (3.3 tex) nylon monofilament and a black 75-denier (35f) nylon multifilament make up the core, and c…
The crystal structure of monoclinic magnesium astrophyllite has been redetermined. The samples were from Khibina alkaline massifs, Russia. K 2 NaNa(Fe,Mn) 4 Mg 2 Ti 2 [Si 4 O 12 ] 2 (OH) 4 (OH,F) 2 , M r = 1202.31, monoclinic, A 2, a = 10.370 (3), b = 23.129 (5), c = 5.322 (1) Å, β = 99.55 (2)°, V = 1258.8 (5) Å 3 , Z…
Phase transitions of liquid crystal PAA, p -azoxyanisole, in porous sol−gels of average pore diameters 8.9, 16, and 20 nm, are investigated using Raman spectroscopy and differential scanning calorimetry. It is found that the phase transition temperatures inside small pores are depressed and the depressions are pore si…
Point defects and structure damages in Si-implanted thermal SiO2 films were examined by photoluminescence (PL) spectra, electron spin resonance spectra, and infrared absorption spectra. Under ∼5 eV excitation, the as-implanted film had two PL bands peaked at 4.3 and 2.4 eV, respectively. After thermal annealing, the p…
Abstract In this two‐part paper, we present a model for the solidification of semicrystalline thermoplastic polymers that links the microscopic and macroscopic length scales. The model accounts for the important physical phenomena occurring during spherulitic cyrstallization and predicts microstructural evolution. In…
The phase equilibria in the Y 2 O 3 ‐Nb 2 O 5 system have been studied at temperatures of 1500° and 1700°C in the compositional region of 0‐50 mol% Nb 2 O 5 . The solubility limits of the C‐type Y 2 O 3 cubic phase and the YNbO 4 monoclinic phase are 2.5 (±1.0) mol% Nb 2 O 5 and 0.2 (±0.4) mol% Y 2 O 3 , respectively,…
A total number of 15 premoulded joints of three 170 kV cable circuits (XLPE and EPR) were equipped with partial discharge (PD) sensors. The developed sensors are based on inductive high frequency coupling of partial discharge pulses occurring in the joints. The PD activity of each joint was monitored during an after l…
Ultradisperse-diamond clusters are shown to be fractal objects, and the character of variation of the fractal dimension in the course of the diamond-graphite phase transition under annealing in an inert atmosphere is studied.
Thermal reactions of magnesium compounds and kaolinite were investigated to obtain dense cordierite ceramics without additives. Magnesium hydroxide was precipitated from aqueous solution in the form of ultrafine hexagonal tabular particles of about 0.1 µm, and heating this mixture with kaolinite in a mole ratio of MgO…
The working zone of a sea urchin tooth is a ceramic‐fiber‐reinforced ceramic‐matrix composite. It is composed of reinforcing calcitic fibers, a matrix of high‐magnesium‐containing calcite crystals, and organic material. It is much harder and tougher than most other calcitic materials. Fracture toughness and microhardn…
Abstract Bacterial polyhydroxyalkanoates (PHAs) are polyesters of 3‐hydroxyacids produced as intracellular granules by a large variety of bacteria, currently receiving much attention because of their potential as renewable and biodegradable plastics. The monomer units in these microbial polyesters are all in the R ‐co…