The GaAs(100) surface is modeled, using a cluster to study the interaction with hydrogen. On the basis of ab initio theory including electron correlations, the most stable structures for the As-terminated surface with adsorbed hydrogen atoms are established. The optimized structure of the modeled cluster without the adsorbate is also obtained. From the computational results of total energy, the activation energy of the dissociation of the hydrogen molecule on the surface was estimated. The cluster with adsorbed hydrogen atoms is more stable than that without hydrogen, although the approach of the hydrogen molecule toward the surface causes an increase in the total energy

Advanced IGBT module technology to realize high reliability and high current capability was presented. The 60,000 cycles long term power cycle capability of the low thermal expansion base module was demonstrated. A stress release tall mounting structure and a ceramic metal pull back structure were shown to be essential for high thermal cycle capability. A multi-end main terminal with multichip substrate and high resistivity sense emitter terminal technology was applied to realize high current capability and uniformity in the large high power module

The spin excitation for a ferromagnetic wire with a domain wall (DW) is studied in a framework of the random phase approximation. We show that the excitation energy due to the DW is much smaller than that for the spin wave. In the spin-wave spectrum, there are lots of peaks or shoulders, which is related to the existence of the DW and the dimension of the leads. Using the results, the energy dissipation of conduction electrons is also discussed

The effect of on-site Coulomb repulsion on the process of resonant tunneling through a small interacting region is studied in the presence of a magnetic field by using the recursive Green's function method within a mean field approximation. The conductance is calculated as a function of the chemical potential mu making use of the Kubo formula, and calculations are performed for single- and double-mode quasi-one-dimensional quantum wires. In a magnetic field, some resonance levels close each other to form a single Landau level, so that the electron correlation in the small region is enhanced, and the mu-dependence of the conductance is changed by rather small value of the Coulomb repulsion. For the double-mode wire a collinear-type electronic state, in which spins in the small region are aligned antiferromagnetically in the x-direction and ferromagnetically in the y-direction, is found to be stable over a wide range of the chemical potential

The magnetic properties of beta-FeSi(2) single crystals were investigated using magnetization and anomalous Hall effect measurements. These measurements clearly show the appearance of superparamagnetism, the origin of which is attributed to defect-induced magnetic aggregates. Unlike previous reports, based on our combined analysis using magnetization and the anomalous Hall effect, we found that two kinds of aggregates, which are magnetically distinct, exist in our samples. Among the two types found, one gives an anomalous Hall term, which follows a side-jump mechanism while the other is a completely new kind, suggesting that magnetic properties of beta-FeSi(2) are very unconventional. The sizes of the aggregates were estimated from our experimental data. (C) 2011 Elsevier B.V. All rights reserved.

Chromosomal integration of the human herpesvirus-6 (HHV-6) genome (CIHHV-6) is an important consideration if HHV-6 DNA is detected during the course of transplantation. A 4-year-old girl with refractory anemia with excess blasts type-2 was diagnosed with CIHHV-6 before a cord blood transplantation. HHV-6 DNA was serially quantitated by polymerase chain reaction assay in the transplant period. The possibility of HHV-6 reactivation in a transplant recipient with CIHHV-6 was suspected in our case.

Temporal variations of photoluminescence (PL) in poly(phenylmethylsilane) (PPMS) films under the irradiation with 325 nm light at room temperature in air have been investigated. The PL intensity from the sigma*-sigma transition shows a temporal decay fitting to a straight line in a log-log plot, where its slope switches from small one (-0.2) to steep one (~-1) at a certain time. This transfer time corresponds to the time when the PL intensity of a 530 nm peak (ascribable to the pi*-sigma transition) begins to decrease and increases proportionally with increasing the molecular weight of PPMS in the range less than 2.2times10 5. The decay properties are discussed by introducing a thermal activated process into the photooxidation

Magnetotransport and magnetic properties have been measured for beta-FeSi2 single crystals from 4.2 to 300 K using a pulsed magnet, a superconducting magnet, and a SQUID magnetometer. Nonlinear Hall effect followed by a normal Hall effect was observed, involving a hysteresis effect at low temperature. The signs of normal Hall coefficients changed from positive to negative ones at around 180 K. The magnetization curves above 180 K are well explained by considering the superparamagnetism. Below 150 K we found that the aggregates of Fe atoms exhibit an inter-aggregate ferromagnetic interaction. At low temperature we also found that the cohesive forces obtained from the rho(H)-B curves are larger than those from the M-B curves. This discrepancy was discussed qualitatively by a proposed model.

A quantum resonance in the conduction through the normal-conductor-superconductor junction is investigated in the presence of a magnetic field using a numerical transfer matrix method. It is shown the dip-pairs in the conductance curve occur at a certain geometry of the system owing to the resonant reflection caused by the interference of the reflected electron and hole waves under a finite magnetic field. By examining a local density of quasiparticles, we found that the feature of the resonant state giving the dip-pair in the conductance (in a magnetic field) is very different from that in a finite bias voltage

This case report describes common oral inflammatory findings leading to the identification of Chediak Higashi syndrome (CHS). A 15-year-old girl presented with an enlarging and painful mass on the upper lip. Two weeks after the initial visit, the mass showed further protrusion in the absence of fever. Magnetic resonance imaging revealed a well-circumscribed cystic lesion with a thick capsule, and suggested an abscess derived from the mucous cyst in the upper lip. Inflammation indices were not elevated; however neutrophils were significantly lower than the normal level. Giant cytoplasmic granules in neutrophils, eosinophils, and lymphocytes, which are pathognomonic of CHS, were noted. The patient displayed brownish-red hair with some grey hair, and partial oculocutaneous albinism. Hepatosplenomegaly was evident on ultrasonography. The final diagnosis was of an oral infection facilitated by the adolescent form of CHS (gene CHS1/LYST at 1q42.1-2). This report offers a reminder that lip swelling may represent the initial manifestation of the inflammatory response in a patient with loss of immunocompetence due to pathologies such as CHS, and may rarely present as the patient's main complaint.