Theoretical Approach to Spin-current Absorption at an Interface

Kazuhiro Tsutsui,Takehito Yokoyama,Kazuhiro Hosono 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.62 No.12

We study the spin current induced by an inhomogeneous spin-orbit coupling due to impurities byusing the Keldysh Green’s function formalism. In particular, we focus on the diffusive contributionsand give their analytical expressions. A spin current is found to be generated in the presence ofboth a gradient in the spin-orbit strength and a gradient in the external electric field. The resultingdiffusive spin current indicates the presence of spin-current absorption at the interface between thematerials with different spin-orbit coupling strengths, which is exemplified with an experimentallyrelevantsetup.

Comparison of the Effects of Early and Conventional Defoliation on Fruit Growth, Quality and Skin Color Development in ‘Fuji’ Apples

Kazuhiro Matsumoto,Tomomichi Fujita,Saki Sato,Jong-Pil Chun 한국원예학회 2017 원예과학기술지 Vol.35 No.4

We compared the quality of ‘Fuji’ apples (Malus × domestica ) from trees whose leaves were not removed (no artificial defoliation; NAD) with apples from trees that underwent early defoliation (ED, treated in mid September and early October) and conventional defoliation (CD, treated in early and mid October). The experiment was conducted in three consecutive years using 15-year-old ‘Fuji’ apple grafted on Malus prunifolia . Fruits were harvested on November 7, 16 or 12 in 2011, 2012 and 2013, respectively. Compared to NAD treatment, ED and CD treatment reduced the fresh weight by 4.7% and 0.6%, respectively. The soluble solids content of NAD apples (14.4°Brix) was slightly higher than that of CD (14.1°Brix) and ED (14.0°Brix) apples. Soluble sugar content, flesh firmness, water-core index, and titratable acidity were not affected by defoliation treatment regardless of treatment timing. The skin blush index of NAD apples (2.3) was inferior to that of CD (3.3) and ED (3.4)- treated apples. Furthermore, artificial defoliation treatments increased skin redness (a*) and yellowness (b*) and significantly improved the degree of skin blush compared to NAD fruits.

Variational Cluster Approach to the Hubbard Model on a Honeycomb Lattice

Kazuhiro Seki,Yukinori Ohta 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.62 No.12

We study the ground-state properties of the Hubbard model on the honeycomb lattice at halffilling. Using the variational cluster approximation, We study the semimetal-insulator transitionand antiferromagnetism as functions of the on-site Coulomb interaction U. When U is switchedon, a small, but finite, single-particle gap appears; thus, we conclude that a tiny gap appears witharbitrary small U > 0. With further increases in U, the system goes into the antiferromagneticstate. We find that the staggered magnetization increases continuously with increasing U and thatthe antiferromagnetic phase transition is of the second order.

Evaluation of Different Culture Conditions of Clostridium bifermentans DPH-1 for Cost Effective PCE Degradation

Kazuhiro Takamizawa,Afroze Syeda Humayra,Yuki Hasegawa,Izumi Nomura,Young C. Chang,Takeshi Sato 한국생물공학회 2005 Biotechnology and Bioprocess Engineering Vol.10 No.1

Clostridium bifermentans strain DPH-1 has already been found to dechlorinate perchloroethylene (PCE) to cis-dichloroethylene (cis-DCE) via trichloroethylene (TCE). In this study, our investigation on different culture conditions of this DPH-1 strain was extended to find a more efficient and cost effective growth medium composition for this DPH-1 strain in bioremediation practices. Temperature dependency of strain DPH-1 showed that the growth starting time and PCE degradation at 15oC was very slow compared to that of 30oC, but complete PCE degradation occurred in both cases. For the proper utilization of strain DPH-1 in more cost effective bioremediation practices, a simpler composition of an effective media was studied. One component of the culture medium, yeast extract, had been substituted by molasses, which served as a good source of electron donor. The DPH-1 strain in the medium containing molasses, in the presence of K2HPO4 and KH2PO4, showed identical bacterial multiplication (0.135 mg protein mL-1h-1) and PCE degradation rates (0.38 M/h) to those of the yeast extract containing medium.

Analysis of the Preference Shift of Customer Brand Selection and its Matrix Structure

Kazuhiro Takeyasu 대한산업공학회 2018 Industrial Engineeering & Management Systems Vol.17 No.3

Focusing that consumers are apt to buy superior brand when they are accustomed or bored to use current brand, a new analysis method is introduced. It is often observed that consumers select the upper class brand when they buy the next time. Suppose that the former buying data and the current buying data are gathered. Also suppose that the upper brand is located upper in the variable array. Then the transition matrix becomes an upper triangle matrix under the supposition that the former buying variables are set input and the current buying variables are set output. Before buying data and after buying data is stated using linear model. When above stated events occur, transition matrix becomes an upper triangular matrix. The goods of the same brand group would compose the Block Matrix in the transition matrix. Condensing the variables of the same brand group into one, analysis becomes easier to handle and the transition of Brand Selection can be easily grasped. In this paper, equation using transition matrix stated by the Block Matrix is expanded to the third order lag and the method is newly re-built. Furthermore the method of condensing the variable stated above is also applied to this new model. These are confirmed by numerical examples. S-step forecasting model is also introduced. This approach makes it possible to identify brand position in the market and it can be utilized for building useful and effective marketing plan.

Detection of Phalange Region Based on U-Net

Kazuhiro HATANO,Seiichi MURAKAMI,Huimin LU,Joo Kooi TAN,Hyoungseop KIM,Takatoshi AOKI 제어로봇시스템학회 2018 제어로봇시스템학회 국제학술대회 논문집 Vol.2018 No.10

Osteoporosis is one of the famous bone diseases. It is a major cause of deteriorating the quality of life, and early detection and early treatment are becoming socially important. Visual screening using Computed Radiography (CR) images is effective for diagnosis of osteoporosis, but there are problems of increasing the burden on doctors, variation in diagnostic results due to differences in experiences of doctors, and undetected lesions. In order to solve this problem, we are working on a computer-aided diagnosis (CAD) system for osteoporosis. In this paper, we propose segmentation methods of the phalange region from the phalangeal CR images as a preprocessing of classification of osteoporosis. In the proposed method, we construct a segmentation model using U-Net, which is a type of deep convolution neural network (DCNN). The proposed method was applied to input images generated from CR images of 101 patients with both hands, and evaluated using the Intersection over Union (IoU) values. The result was 0.914 in IoU.

Knots in homology lens spaces determined by their complements

Kazuhiro Ichihara,Toshio Saito 대한수학회 2022 대한수학회보 Vol.59 No.4

In this paper, we consider the knot complement problem for not null-homologous knots in homology lens spaces. Let $M$ be a homology lens space with $H_1(M; \mathbb{Z}) \cong \mathbb{Z}_p$ and $K$ a not null-homologous knot in $M$. We show that, $K$ is determined by its complement if $M$ is non-hyperbolic, $K$ is hyperbolic, and $p$ is a prime greater than 7, or, if $M$ is actually a lens space $L(p,q)$ and $K$ represents a generator of $H_1(L(p,q))$.

Development of a Led-Artificial Sunlight Source System Capable of Controlling Relative Spectral Power Distribution

Kazuhiro Fujiwara,Toshinari Sawada 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-

The Variation in the Lumbar Facet Joint Orientation in an Adult Asian Population and Its Relationship with the Cross-Sectional Area of the Multifidus and Erector Spinae

Kazuhiro Sugawara,Masaki Katayose,Kota Watanabe 대한척추외과학회 2016 Asian Spine Journal Vol.10 No.5

Study Design: Cross-sectional study of healthy volunteers. Purpose: We aimed to investigate the variation in the lumbar facet joint orientation in an adult Asian population. The relationship between the facet joint orientation and muscle cross-sectional area (CSA) of multifidus and erector spinae was also clarified. Overview of Literature: Several studies have reported that lumbar pathologies, such as lumbar spondylolysis and degenerative spondylolisthesis, were related to the horizontally shaped lumbar facet joint orientation at the lower lumbar level. However, data regarding variations in the facet joint orientation in asymptomatic subjects have not been well documented. Methods: In 31 healthy male adult Asian volunteers, the facet joint orientation and CSA of multifidus and erector spinae were measured using magnetic resonance imaging at the L4–5 and L5–S1 levels. Variation in the facet joint orientation was examined using coefficients of variation (CV). Pearson’s product-moment coefficient was used to investigate the relationship between the facet joint orientation and CSA of multifidus and erector spinae. Results: Lumbar facet joint orientation had a wider range of variation at L5–S1 (CV=0.30) than at L4–5 (CV=0.18). The L4–5 facet joint orientation had a weak but significant correlation with the CSA of erector spinae (r =0.40; p=0.031). The CSA of the multifidus had no relationship with the facet joint orientation at the L4–5 (r =0.19; p =0.314) and the L5–S1 level (r =0.19; p =0.312). Conclusions: The lumbar facet joint orientation was found to have a wide variation, particularly at the L5–S1 in the Asian adult population, and the facet joint orientation had a relationship with the CSA of the erector spinae at the L4–5.

GCT Technologies and their applications

Kazuhiro Kurachi,Kazunori Taguchi,Gourab.Majumdar 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

Continuous development and evermore demanding applications, have led to significant improvements in high power semiconductors devices to date. High power devices such as GTO (Gate Turn Off Thyristor), GCT (Gate Commutated Turn Off Thyristor) and HVIGBT (High Voltage Insulated Gate Bipolar Transistor) module have been widely adopted in large capacity power electronics equipment such as electric railway, power management, power transportation and industrial fields. However, long term reliability is expected from these applications and from the viewpoint of environmental management, reduction in equipment size and improvement in efficiency are required. Until 20 years ago, the mainstream device for high power electronics was the GTO but since the late 1990s, they have been replaced with new devices such as GCTs and HVIGBTs. Here we focus on the press-pack GCT with a hermetic structure that can be expected to have a long lifetime and report on some of the applied technologies and their application.