Water-tree characteristics in low-density PE under simulatedinverter voltages

Water tree characteristics have been investigated for low-density polyethylene by applying power-frequency ac voltages with high-frequency components, which are simulated output voltages of a pulse-width-modulation inverter. If we compare the water-tree length among single-frequency voltages, the water tree grows faster if the frequency is higher. However, if we superpose a power-frequency voltage on the high-frequency voltage, tree growth is suppressed. The tree length becomes shorter if the superposed power-frequency voltage is higher. This surprising result is explainable by considering that the zero-crossing of the applied voltage plays an important role in tree propagation     

Properties of Heavily Mn-doped GaMnAs with Curie Temperature of 172.5 K

The authors have investigated the magnetic properties of heavily Mn-doped ferromagnetic semiconductor Ga_1−x Mn _x As thin film with the Mn concentration x of 15.2% grown by molecular-beam epitaxy at relatively high growth temperature of 250 °C. Magnetic circular dichroism and the anomalous Hall effect measurements indicate that this thin film holds the intrinsic ferromagnetic semiconductor features. By low-temperature annealing, the resistivity was significantly decreased and the Curie temperature was largely enhanced from 95 K to 172.5 K.     

Mechanical properties and micro-fracture behaviors of flat braided composites with a circular hole

In this study, attention is paid to braided fabrics as the form of reinforcing fiber in composite materials and the influence of a circular hole on the mechanical properties of a flat braided composite is investigated. Two types of specimens were prepared: a flat braided bar with a braided hole which fiber bundle continuously oriented around the hole and with a machined hole. From the results of static tensile test, the strength of the flat bar with a braided hole was higher than that of the one with the machined hole. Furthermore, difference of damage propagation in the two types of flat braided composites with a circular hole was confirmed by micro-damage observation and factors that caused initial micro-fracture obtained by experiments were identified by numerical approaches.     

Photoluminescence in Polyamide/mica and Polyethylene/ MgO Nanocomposites Induced by Ultraviolet Photons

Nature of electronic states in the energy band is investigated by means of optical absorption and photoluminescence induced by vacuum ultraviolet photons for polyamide-6/mica and low-density polyethylene/MgO nanocomposites. The nanofiller loading does not affect the absorption spectra of polyamide samples. Contrary to this, two absorption bands are induced at around 5.0 and 6.2 eV by the nanofiller loading in polyethylene samples, but they are due to absorption by the fillers. A luminescence band is observed at around 3.0 eV in polyamide samples, whereas three luminescence bands are observed at around 4.3, 3.7, and 2.9 eV in polyethylene samples. However, for all the luminescence bands, neither emission nor excitation energies change by the addition of nanofillers. Decay profiles of all the luminescence bands are essentially unchanged by the nanofiller loading. Moreover, no new PL bands are induced in the observed wavelength range. These results indicate that localized states, at least as far as the ones that can emit luminescence photons with intensities more than the sensitivity of the present research, are not induced by the nanofiller loading.     

Is there a universal need for positive self-regard?

It is assumed that people seek positive self-regard; that is, they are motivated to possess, enhance, and maintain positive self-views. The cross-cultural generalizability of such motivations was addressed by examining Japanese culture. Anthropological, sociological, and psychological analyses revealed that many elements of Japanese culture are incongruent with such motivations. Moreover, the empirical literature provides scant evidence for a need for positive self-regard among Japanese and indicates that a self-critical focus is more characteristic of Japanese. It is argued that the need for self-regard must be culturally variant because the constructions of self and regard themselves differ across cultures. The need for positive self-regard, as it is currently conceptualized, is not a universal, but rather is rooted in significant aspects of North American culture. Conventional interpretations of positive self-regard are too narrow to encompass the Japanese experience. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The influence of reaction layer on the strength of aluminum/steel joint welded by resistance spot welding

We investigated the influence of interfacial reaction layer on the strength of resistance spot welded aluminum/steel joint by analyzing fracture surface and observing interfacial structure. The results revealed that the interfacial strength was approximately 6.509 MPa in the case that the reaction layer thickness exceeds 1.5 µm.     

Improvement of functional properties of bovine serum albumin through phosphorylation by dry-heating in the presence of pyrophosphate

ABSTRACT:  Bovine serum albumin (BSA) was phosphorylated by 2 methods. One is dry-heating in the presence of pyrophosphate, and the other is conjugation with maltopentaose through the Maillard reaction and subsequent dry-heating in the presence of pyrophosphate. The phosphorus content of BSA was increased to approximately 0.45% by dry-heating at pH 4.0 and 85 °C for 5 d in the presence of pyrophosphate, and approximately 0.91% by glycation and subsequent phosphorylation. The circular dichroism spectra showed that the change of secondary structure in the BSA molecule by phosphorylation was mild. However, tryptophan fluorescence intensity of BSA decreased by phosphorylation. The differential scanning calorimetry thermograms of BSA showed a disappearing of the 1st peak and a lowering of the 2nd peak denaturation temperature by phosphorylation. These results indicated molten (partially unfolded) conformations of BSA formed by both phosphorylation methods. The functional properties of BSA such as heat stability and calcium phosphate solubilizing ability were improved by phosphorylation alone and further by phosphorylation after glycation. Transparent gels of BSA with relatively high water-holding capacity were obtained by phosphorylation alone, and the immunogenicity of BSA was reduced significantly by glycation and phosphorylation, respectively.     

Structural Disorder and Intracrystalline Microtexture of α'H-(Ba0.24Ca0.76)2SiO4

The structural disorder and twin microtexture of (Ba_0.24Ca_0.76)₂SiO₄ crystal were investigated by X-ray powder diffraction, precession method, and optical microscopy. The crystal at 298 K was orthorhombic (space group Pnma , Z =4) with a =0.70490(5) nm, b =0.55399(4) nm, c =0.95532(7) nm, and V =0.37306(4) nm³. The crystal structure was satisfactorily described by a split-atom model, involving the positional disorder of Ba/Ca and O atoms across the (010) mirror plane. The crystal was found to be isostructural with α'_H-Ca₂SiO₄, thus regarded as the stabilized α'_H phase. The crystal grain was composed of orthorhombic domains in three different orientations. The unit cells within each domain were related to one another by the threefold pseudo-symmetry axis lost during the α-to-α'_H transition. Each domain was most probably made up of sub-domains of the two mirror-related structural configurations with P 2₁/ n symmetry.