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Determination of Ring-OSF Position in Czochralski Silicon Single Crystals by Numerical Analysis of Distribution of Grown-in Defects

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Journal of Rare Earths 2006年第Z1期24卷 213-216页

作者： Sunao Abe takahiro Terada Yasutada Nakagawa Kazuhiko Kashima Silicon Company Toshiba Ceramics Co.Ltd. 6-861-5 Higashikou Seirou-machi Niigata 957-0197 Japan Corporate Manufacturing Engineering Center Toshiba Corp. 33 Shin-isogo Isogo-ku Yokohama Kanagawa 235-0017 Japan Corporate Manufacturing Engineering Center Toshiba Corp. 33 Shin-isogo Isogo-ku Yokohama Kanagawa 235-0017 Japan New Business Creation Division Toshiba Ceramics Co.Ltd. 1-6-3 Osaki Shinagawa-ku Tokyo 141-0032 Japan

A numerical analysis technique that incorporates Voronkov's model were examined and used to estimate the distribution of defects during crystal growth. By comparisons of the distribution of the density of LSTD and the position of R-OSF in non-nitrogen-doped (non-N-doped) and nitrogen-doped (N-doped) silicon crystals, it is found that the results of the numerical analyses agree with practically evaluated data. The observations suggest that the R-OSF nucleus is a VO2 complex that is formed by bonds between oxygen atoms and residual vacancies consumed during the formation of void defects. This suggests that Voronkov's model can be used to accurately predict the generation and growth of defects in silicon crystals. This numerical analysis technique was also found to be an effective method of estimating the distribution of defects in silicon crystals during crystal growth.

关键词： computer simulation nucleation point defects volume defect semiconducting silicon

Chemical Composition Control of Non-Metallic Inclusions in High Alloy Steel Production Process

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Journal of Iron and Steel Research International 2011年第S2期18卷 275-282页

作者： Naoya SATOH takahiro MIKI Mitsutaka HINO Department of Metallurgy Graduate School of Engineering Tohoku University now Yasuki Works Hitachi Metal Corporation Department of Metallurgy Graduate School of Engineering Tohoku University Professor Emeritus Tohoku University now Hokkaido Polytechnic College 3-130 Zenibako Otaru Hokkaido 047-0292 Japan

There is a close relation between the characteristics of products and the chemical composition control of inclusions in steelmaking process. Therefore, it is very important for a warranty of product’s characteristics to improve inclusion quality resulting in defective products. In the present work, the control technique of inclusions’ chemical composition is discussed thermodynamically based on the Redlich-Kister type polynomial to metallic solution and regular solution model to molten oxide solution. It is very effective for the precise chemical composition control of oxides to determine the concentration of deoxidizers based on the thermodynamic relation among dissolved deoxidizers and oxygen, because it is known that oxide inclusions are equilibrated with them in molten steel in the steel making process. High alloy steel production process was focused in the present work.

关键词： high alloy steel non-metallic inclusion deoxidation equilibrium redlich-Kister type polynomial regular solution model

Towards understanding network topology and robustness of logistics systems

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Communications in Transportation Research 2022年第1期2卷 75-94页

作者： takahiro Ezaki Naoto Imura Katsuhiro Nishinari Research Center for Advanced Science and Technology The University of TokyoTokyo153-8904Japan

Advanced integration of logistics systems has been promoted for competitiveness and *** of transport operations increases complexity at a network level,which reduces the predictability of the response of the system to ***,our understanding of the behavior of such systems is still *** particular,the topology of the network,which changes as the systems are integrated,is an important factor that affects the performance of the entire *** of such mechanisms would be useful in the design and evaluation of integrated ***,we developed a simple simulation framework for logistics networks that extracts the essence of the *** performed extensive numerical experiments for three scenarios that mimic changes in demand:(i)locally and temporally increased traffic demand,(ii)globally and temporally increased traffic demand,and(iii)permanent change in demand pattern,under various conditions on the type of route-finding algorithm,network structure,and transportation *** route-finding algorithms were more effective in square lattice and random networks,which contained many bypass routes,than in hub-andspoke ***,the square lattice and random networks were robust to the change in the *** suggest that such preferable properties are only present in networks with redundancy and that the bypass structure is an important criterion for designing network *** also performed a realistic case study that mimics interregional truck transport in Japan and confirmed that our conclusions are applicable to a practical problem.

关键词： Horizontal cooperation Network logistics Monte Carlo Simulations Robustness

Semisolid casting with ultrasonically melt-treated billets of Al-7mass%Si alloys

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China Foundry 2012年第1期9卷 78-83页

作者： Yoshiki Tsunekawa Masahiro Okumiya takahiro Motomura Toyota Technological Institute

Abstract： The demand for high performance cast aluminum alloy components is often disturbed by increasing impurity elements, such as iron accumulated from recycled scraps. It is strongly required that coarse plate-like iron compound of β-Al5FeSi turns into harmless form without the need for applying refining additives or expensive virgin ingots. The microstructural modification of Al-7mass%Si alloy billets with different iron contents was examined by applying ultrasonic vibration during the solidification. Ultrasonically melt-treated billets were thixocast right after induction heating up to the semisolid temperature of 583 ℃, the microstructure and tensile properties were evaluated in the thixocast components. Globular primary reAl is required to fill up a thin cavity in thixocasting, so that the microstructural modification by ultrasonic melt-treatment was firstly confirmed in the billets. With ultrasonic melt-treatment in the temperature range of 630 ℃ to 605 ℃, the primary α-AI transforms itself from dendrite into fine globular in morphology. The coarse plate-like β-AIsFeSi compound becomes markedly finer compared with those in non-treated billets. Semisolid soaking up to 583 ℃, does not appreciably affect the size of β-AIsFeSi compounds; however, it affects the solid primary reAl morphology to be more globular, which is convenient for thixocasting. After thixocasting with preheated billets, eutectic silicon plates are extremely refined due to the rapid solidification arising from low casting temperature. The tensile strength of thixocast samples with different iron contents does not change much even at 2mass% of iron, when thixocast with ultrasonically melt-treated billets. However, thixocast AI-7mass%Si-2mass%Fe alloy with non-treated billets exhibits an inferior strength of 80 MPa, compared with 180 MPa with ultrasonically melt-treated billets. The elongation is also improved by about a factor of two in thixocastings with ultrasonically melt-treated billets

关键词： cast Al-Si alloy ultrasonic radiation thixocasting α-Al iron compound

Differential Responses Between Monocytes and Monocyte-Derived Macrophages for Lipopolysaccharide Stimulation of Calves

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Cellular & Molecular Immunology 2009年第3期6卷 223-229页

作者： Yijie Guo Guoqi Zhao Sachi Tanaka takahiro Yamaguchi Laboratory of animal nutrition Graduate School of Animal Science and Technology Yangzhou University Wen Hui Road Jiangsu 225009 China Laboratory of Functional Morphology Graduate School of Agricultural Science Tohoku University 1-1 Tsutsumidori-Amamiyamachi Aobaku Sendai 981-8555 Japan

In this experiment Toll-like receptor expression pattern in monocytes and monocyte-derived macrophages by lipopolysaccharide （LPS） stimulation was examined. Jugular venous blood was collected from four Japanese calves, and the peripheral blood mononuclear cells （PBMCs） were isolated. The cells were directly used for collecting monocytes by magnetic cell sorting or cultured for 7 days to collect monocyte-derived macrophages in Repcell. Then we analyzed the mRNA expression pattern of TLRs and cytokines in monocytes and monocyte-derived macrophages after LPS stimulation for 24 h. LPS stimulation of both monocytes and monocyte-derived macrophages resulted in an increase in the levels of mRNA transcripts for TNF-α IL-6 and IL-8. Moreover, TNF-α and IL-6 mRNA expressions were significantly augmented by LPS stimulation in monocyte-derived macrophages. TLRs mRNA expressions were unchanged after LPS stimulation of monocytes, while TLRs mRNA expressions in monocyte-derived macrophages were complicated. TLR1, 3, 5, 8 and 10 were significantly decreased after LPS stimulation and there were no differences in the mRNA expressions of TLR2, 4, 6 and 7 between the groups of control and LPS stimulation. Besides, no expression of TLR9 was found. As antigen presenting cells, monocytes and monocyte-derived macrophages respond differently to LPS, so they may have different functions in the innate immune system.

关键词： Toll-like receptor monocyte monocyte-derived macrophage bovine

Influence of Fine Sediment on the Fluidity of Debris Flows

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Journal of Mountain Science 2013年第2期10卷 233-238页

作者： Norifumi HOTTA takahiro KANEKO Tomoyuki IWATA Haruo NISHIMOTO Faculty of Life and Environmental Sciences University of Tsukuba3058577 IbarakiJapan Faculty of Agriculture The University of Tokyo1138657 TokyoJapan Graduate School of Agricultural and Life Sciences The University of Tokyo1138657 TokyoJapan

Debris flows include a great diversity of grain sizes with inherent features such as inverse grading, particle size segregation, and liquefaction of fine sediment. The liquefaction of fine sediment affects the fluidity of debris flows, although the behavior and influence of fine sediment in debris flows have not been examined sufficiently. This study used flume tests to detect the effect of fine sediment on the fluidity of laboratory debris flows consisting of particles with various diameters. From the experiments, the greatest sediment concentration and flow depth were observed in the debris flows mixed with fine sediment indicating increased flow resistance. The experimental friction coefficient was then compared with the theoretical friction coefficient derived by substituting the experimental values into the constitutive equations for debris flow. The theoretical friction coefficient was obtained from two models with different fine-sediment treatments： assuming that all of the fine sediments were solid particles or that the particles consisted of a fluid phase involving pore water liquefaction. From the comparison of the friction coefficients, a fully liquefaction state was detected for the fine particle mixture. When the mixing ratio and particle size of the fine sediment were different, some other eases were considered to be in a partially liquefied transition state. These results imply that the liquefaction of fine sediment in debris flows was induced not only by the geometric conditions such as particle sizes, but also by the flow conditions.

关键词： Debris flow Fine sediment Friction coefficient Liquefaction Open channel Reynolds stress

Shearing Mechanism of Straight Thin Copper Wires at Connecting Terminal due to Lightning Current

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Plasma Science and Technology 2007年第6期9卷 752-755页

作者：胡小博 takahiro OTSUKA Toru IWAO Tsuginori INABA Chuo University Tokyo 112-8551Japan Toko Electric Corporation Saitama 349-0192Japan Musashi Institute of Technology Tokyo 158-8557Japan

When a lightning current is impressed through a copper wire, the copper wire would be melted. A straight thin copper wire with a diameter of 0.1 mm,~ is melted due to the specific melting Joule heating （j^2t）m in an adiabatic condition. However, it has been recognized in the experiment that the thicker copper wires of φ1 mm are not completely melted, but sheared mainly at the connecting terminal by a relatively low impulse current. Electro-magnetic mechanical shearing stress, etc. are discussed in addition to the conventional Joule heating. New broken mechanisms were presumed and proved in the additional experiments.

关键词： lightning copper wire broken

Experimental Studies on Debris Flow with Logs Focusing on Specific Weight Difference of Log Species

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Journal of Mountain Science 2013年第2期10卷 315-325页

作者： Haruki WATABE takahiro ITOH Kazuhiko KAITSUKA Shigeki NISHIMURA Nippon Koei Co. Ltd.2304InariharaTsukubaIbaraki 300-1259Japan

There are many experimental approaches,field investigations and numerical calculations for movements of woods in a clear water and debris ***,kinematic conditions for accumulated logs and the interactions between a main flow and logs have not been fully *** for woods need taking into account the characteristics of tree species such as conifer and broad-leaf trees and of shapes such as root swells and *** the present study,we focus on the differences in specific weight of conifer and broad-leaf trees with some moisture in a sediment-water mixture flow with narrow flow width,and consider that conifer and broad-leaf tree are floating and submerged solid phase,*** tests are conducted in steady flow of clear and debris flow over a rigid bed in order to evaluate conifer and broad-leaf tree movement in clear water and debris *** data indicates that dimensionless transverse diffusion coefficient can be 0.1 to 0.4 and 0.3 to 0.9 in flow *** diffusive characteristics seem to be independent of Reynolds number and Froude number,but dependent of bed slope,i.e.,gravity,though detailed considerations are needed to discuss about flow characteristics such as spatial eddy structures,momentum transfer induced by interactions of logs and so on.

关键词： Debris flow Driftwood Specificweight Log Flume test

Hydraulic model tests for evaluating sediment control function with a grid-type Sabo dam in mountainous torrents

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International Journal of Sediment Research 2013年第4期28卷 511-522页

作者： takahiro ITOH Shigeo HORIUCHI Takahisa MIZUYAMA Kazuhiko KAITSUKA NIPPON KOEI Co. Ltd Pasco Corporation Graduate School of Agriculture Kyoto University NIPPON KOEI Co. Ltd.

There are two kinds of Sabo dams in order to control sediment transport by debris flow and flash floods in mountainous area,which arc closed and open-type’s *** Japan,open-type’s Sabo dams are constructed taking into account the continuity of sediment routing from upstream to downstream reach in a basin.A plan to construct a 20 m high grid-type Sabo dam which can capture a sediment volume of 400,000 nr is proposed in the Amahata river basin in *** model tests are conducted to decide on the section for a dam(Section A,B) and the grid size such as clearance of vertical/horizontal bars for evaluating the *** runs of flume tests are conducted and the sediment control function of the Sabo dam is discussed using several experimental data such as dimensionlcss sediment runoff rate from Sabo dam,temporal changes of bed profile and mean diameter and so *** was found that sediment deposition in sediment storage area of Sabo dam was affected by curved channel,and that next the grid size of steel bars and thirdly the section of a dam was able to capture sediment in storage area of Sabo *** was controlled well in the section B and in the grid size of l.0×d95,and the problems related to sediment runoff after sediment capturing in Sabo dam are pointed out.

关键词： Hydraulic model tests Debris flow Grid-type Sabo dam Sediment storage