Tohru Nakamura

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Vertical structured GaN power devices have recently been attracting a great interest because of their potential on extremely high-power conversion efficiency. This letter describes increased breakdown voltages in the vertical GaN p-n diodes fabricated on the free-standing GaN substrates. By applying multiple lightly Si doped n-GaN drift layers to the p-n(More)
Variations in molecular electronic structures related to conformational change are exceedingly attractive because of their key role in the understanding and development of functional processes in molecular electronics and biology. We observed, for the first time, the novel phase switching of a photoactive isomeric molecule,(More)
We report vertical GaN-on-GaN p-n diodes with a breakdown voltage (BV) of 1.7 kV and a low differential specific ON-resistance R<sub>ON</sub> of 0.55 mQ &#x00B7; cm<sup>2</sup> with current spreading considered (or 0.4 mQ &#x00B7; cm<sup>2</sup> using the diode bottom mesa size), resulting in a figure-of-merit (V<sub>B</sub><sup>2</sup>/R<sub>ON</sub>) of(More)
BACKGROUND/AIMS PiggyBac transposable element derived 1 (PGBD1) encodes a molecule involved in epigenetic mechanisms that have been implicated in Alzheimer's disease (AD), and recent genome-wide association studies and meta-analyses have indicated that a single nucleotide polymorphism (SNP), rs3800324, in PGBD1 could be associated with AD and the age of(More)
Adsorption states of dioctyl dichalcogenides (dioctyl disulfide, dioctyl diselenide, and dioctyl ditelluride) arranged on Au(111) have been studied by X-ray photoelectron spectroscopy (XPS), infrared-visible sum-frequency generation (SFG), and ultraviolet photoelectron spectroscopy (UPS). XPS measurements suggest that dioctyl dichalcogenides dissociatively(More)
Fabrication of fully self-aligned heterojunction bipolar transistors (HBTs) by selective emitter regrowth is described. Scaled devices with emitter dimensions as small as 0.4/spl times/7 /spl mu/m/sup 2/ demonstrate current gain up to 29, with successful suppression of surface recombination effects. The RF characteristics of a 1.4/spl times/11 /spl mu/m/sup(More)
Prussian blue is a historical pigment synthesized for the first time at the beginning of 18th century. Here we demonstrate that the historical pigment exhibits surprising adsorption properties of gaseous ammonia. Prussian blue shows 12.5 mmol/g of ammonia capacity at 0.1 MPa, whereas standard ammonia adsorbents show only 5.08-11.3 mmol/g. Dense adsorption(More)
We report a surface mount type LD (laser diode) module using transfer molding. The LD with markers is passively aligned to an Si (silicon) substrate with a marker and bonded using Au/Sn solder, after a monitor PD (photodiode) is flip-chip bonded. A cleaved singlemode fiber with a ferrule is laidinaV-groove f o r m e d b y a n i s o t o r o p i c e t c h i n(More)
Organic ditellurides (R2Te2 where R = n-butyl (C4), n-octyl (C8), and n-cetyl (C16)) were synthesized, and their adsorption states after oxidation on Au(111) surfaces were studied by X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), theoretical analyses, near-edge X-ray absorption fine structure (NEXAFS) measurements,(More)
Immunity is based on self/nonself discrimination. In vertebrates, two major systems, innate and adaptive immune systems, constitute host defense against invading microbes. Adaptive immunity is characterized by specific immune responses through B- or T-cell antigen receptors that are generated by somatic recombination, whereas nonspecific responses to(More)