Masahiro Yoshida

Realizing large-scale single-mode, high-power, high-beam-quality semiconductor lasers, which rival (or even replace) bulky gas and solid-state lasers, is one of the ultimate goals of photonics and laser physics. Conventional high-power semiconductor lasers, however, inevitably suffer from poor beam quality owing to the onset of many-mode oscillation^1,2, and, moreover, the oscillation is destabilized by disruptive thermal effects under continuous-wave (CW) operation^3,4. Here

We report a (51)V-NMR study on a high-quality powder sample of volborthite Cu3V2O7(OH)2 . 2H2O, a spin-1/2 Heisenberg antiferromagnet on a distorted kagome lattice formed by isosceles triangles. In the magnetic fields below 4.5 T, a sharp peak in the nuclear spin-lattice relaxation rate 1/T(1) accompanied with line broadening revealed a magnetic transition near 1 K. The low temperature phase shows anomalies such as a Lorentzian line shape, a 1/T(1) proportional, variantT behavior indicating dens

Abstract Light detection and ranging (LiDAR) is a key technology for smart mobility of robots, agricultural and construction machines, and autonomous vehicles. However, current LiDAR systems often rely on semiconductor lasers with low-quality, large-divergence, and asymmetric beams, requiring high-precision integration of complicated lens systems to reshape the beam. Also, due to the broad linewidth and the large temperature dependence of their lasing spectrum, a bandpass filter with broad bandw

We found the occurrence of thermophilic reversible gamma-resorcylate decarboxylase (gamma-RDC) in the cell extract of a bacterium isolated from natural water, Rhizobium sp. strain MTP-10005, and purified the enzyme to homogeneity. The molecular mass of the enzyme was determined to be about 151 kDa by gel filtration, and that of the subunit was 37.5 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis; in other words, the enzyme was a homotetramer. The enzyme was induced specifically

A mark-release-recapture of Culex pipiens pallens was conducted in an urban area of Japan during June 26-29, 2007. Larvae naturally occurring in rain gutters were collected and reared to adults in a laboratory. A total of 10,183 emerging female Cx. pipiens pallens of 4-8 days old were marked with fluorescent dye and released from one site. Recapture was made on 4 consecutive days using 41 Centers for Disease Control and Prevention traps with 1 kg of dry ice and human landing collection, and 121

Abstract The cooperative concomitant action of maltose phosphorylase (MP), trehalose phosphorylase (TP), β‐amylase and a starch debranching enzyme (pullulanase, isoamylase) was investigated to develop a more efficient method for preparing trehalose from starch. About 40 and 51—56% as solid basis of 25% (w/v) liquefied potato starch were converted to trehalose by the combination of soybean β‐amylase and the crude enzyme preparation (MTA) containing MP, TP and a saccharogenic amylase from a strain

We identified a gene cluster that is involved in the gamma-resorcylate (2,6-dihydroxybenzoate) catabolism of the aerobic bacterium Rhizobium sp. strain MTP-10005. The cluster consists of the graRDAFCBEK genes, and graA, graB, graC, and graD were heterologously expressed in Escherichia coli. Enzymological studies showed that graD, graA, graC, and graB encode the reductase (GraD) and oxygenase (GraA) components of a resorcinol hydroxylase (EC 1.14.13.x), a maleylacetate reductase (GraC) (EC 1.3.1.

We investigate electric-field induced redshifts of photoluminescence from individual single-walled carbon nanotubes. The shifts scale quadratically with field, while measurements with different excitation powers and energies show that effects from heating and relaxation pathways are small. We attribute the shifts to the Stark effect and characterize nanotubes with different chiralities. By taking into account exciton binding energies for air-suspended tubes, we find that theoretical predictions

Abstract The fabrication of air/semiconductor two-dimensional photonic crystal structures by air-hole-retained crystal regrowth using tertiary-butyl arsine-based metal–organic vapor-phase epitaxy for GaAs-based photonic crystal lasers is investigated. Photonic crystal air holes with filling factors of 10–13%, depths of ∼280 nm, and widths of 120–150 nm are successfully embedded. The embedded air holes exhibit characteristic shapes due to the anisotropy of crystal growth. Furthermore, a low lasin

Effects of gate oxide thickness on the hot electron induced degradation in LDD MOSFETs are studied. The device with thinner gate oxide causes less drain current reduction under the same bias stress condition in spite of its highersubstrate current. The relationship between the increase of parasitic drain resistance after stress test and gate oxide thickness shows square dependence. Then the model is proposed to explain that the amount of generated negative charge markedly decrease with decrease