Characterization of Schottky barrier diodes on a 0.5-inch single-crystalline CVD diamond wafer

In this study, Schottky barrier diodes were fabricated on a 0.5-inch single-crystalline diamond wafer, and the quality of the wafer as well as the performance of the devices were characterized. A rocking curve map indicated that the FWHM of the central 8 × 8-mm region was 10–50 arc sec, which is similar to that of high-quality HPHT single-crystalline diamond. The fabricated pVSBDs on the p^?/p⁺ stacked layer showed a high operation limit for the electrical field, with the mean value of this limit being higher than 2.5 MV/cm when the electrode was smaller than 300 µm. The performance of the devices seemed to be associated with the quality of the wafer. This indicates that the leakage current of a device is determined by the quality of the diamond wafer on which it is fabricated.     

Study of rocking motion of rigid body with slide contact

The purpose of this study is to formulate the motion of a rigid body with unilateral contact problems by applying techniques of multibody dynamics and to analyze the issue of rocking condition of rigid bodies with slide contact. In To investigate rocking motion with slide contact, we formulate for dynamics of a simple rigid body system with a unilateral contact model. Judgment for the occurrence of contact between a rigid body and a base is applied. The planar motion of a rigid body system having a simple shape and both with and without slide cases is assumed. Using constraint conditions for the contact as algebraic equations, the rocking motion of the rigid body, including slide and frictional force, is analyzed. The differential algebraic equation is solved by the augmented method with Lagrange multipliers, using generalized coordinates and independent variables that describe the contact points. The influence of the frequency and amplitude of disturbance given to the base is discussed. This paper was presented at the 4th Asian Conference on Multibody Dynamics(ACMD2008), Jeju, Korean, August 20–23, 2008. Keisuke Nozaki is graduate student at Sophia University in Tokyo, Japan. Yoshiaki Terumichi received a Ph.D. degree in Mechanical Engineering from keio University in 1994. Dr. Terumichi is currently a Professor at the Department of Engineering and Applied Sciences at Sophia University in Tokyo, Japan. He is currently contributing as a member of Advisory Boad Eccomas Thematic Conference “Multibody Dynamics 2009” and an editor of the International Journal of System Design and Dynamics of JSME. His research field is on multibody dynamics, vehicle dynamics, and pattern formation phenomena. Kazuhiko Nishimura received a B.S. degree in Aerospace Engineering from the University of Tokyo in 1994. He has worked for the Central Japan Railway Company (CJR) since 1994. As an engineer of the railway industry, he also studied mechanical engineering at the University of Michigan and received his M.S. degree in 2003. He is currently a senior research engineer at Komaki Research Center of CJR and also a Ph. D. candidate at Sophia University. His research/engineering interests are in the area of vehicle/track interaction issues in high speed railway system. Kiyoshi Sogabe received a B.S. degree in Mechanical Engineering from Kyusyu Institute of Technology, Japan. He received M.S. and Dr. Eng degrees from the University of Tokyo in 1971 and 1975, respectively. Dr. Sogabe is currently a Professor in the Department of Engineering and Applied Sciences, Faculty of Science and Technology, Sophia University, Tokyo, Japan. Dr. Sogabe was the Dean of the faculty during April 2004–March 2008. His main research interests are in the field of dynamic analysis of machines and structures, multibody dynamics.     

Synthesis and thermal characterization of novel poly(tetramethyl-1,3-silphenylenesiloxane) derivative bearing adamantyl moiety

A novel poly(tetramethyl-1,3-silphenylenesiloxane) derivative having adamantyl moiety, i.e., poly(tetramethyl-5-adamantyl-1,3-silphenylenesiloxane) (P1) was synthesized by solution polycondensation of a novel disilanol monomer, i.e., 1-[3,5-(dimethylhydroxysilyl)phenyl]adamantane (M1). M1 was prepared by the Grignard reaction using chlorodimethylsilane and 1-(3,5-dibromophenyl)adamantane, followed by the hydrolysis catalyzed by 5% palladium on charcoal. P1 exhibited the good solubility in common organic solvents, such as tetrahydrofuran (THF), chloroform, dichloromethane, benzene, and toluene at ambient temperature. P1 was also soluble in hot hexane, diethyl ether, and ethyl acetate. The glass transition temperature (T _g) and temperature at 5% weight loss (T _d5) of P1 were 85 and 517 °C, respectively, and much higher than those of poly(tetramethyl-1,3-silphenylenesiloxane), indicating that P1 is a new polysiloxane derivative with good solubility as well as good thermostability.     

Charge ordering state of mixed-valence (TP-EDTT)3(PF6)2

4,5-Ethylenedithio-2-(thiopyran-4-ylidene)-1,3-dithiole (TP-EDTT) and its radical cation salts were prepared. Conventional galvanostatic electrocrystallization gave (TP-EDTT)₂SbF₆, (TP-EDTT)GaCl₄, (TP-EDTT)ReO₄, and (TP-EDTT)₃(PF₆)₂. The variation of bond lengths upon the charge of each molecule was examined based on 0, +0.5, and +1.0-charged TP-EDTT molecules. Applying the relationship between the charge and the bond lengths to the donor molecules, (TP-EDTT)₃(PF₆)₂ was proved to be a charge ordering system.     

Modification of nitride layer on cold-work tool steel by laser melting and friction stir processing

The microstructural control of the nitrided case on a cold-work tool steel (SKD11) plate by laser melting and friction stir processing (FSP) was studied. The laser melting and the FSP were used as a pretreatment for the nitriding to refine the microstructure of the SKD11. The diffusion zone of the nitrided case on the SKD11 plate contained thick brittle boundary lines consisting of local formed nitride particles. On the other hand, the microstructure of the diffusion zone was very uniform and the thick brittle boundary lines disappeared as a result of the combined treatment of the laser melting and the FSP before the nitriding process.     

Numerical Simulation of New Friction Welded Joints

In developing the new friction welding technology, the thermal elastic-plastic stress analysis by the finite element method was carried out to seek the suitable welding conditions such as the friction pressure, the friction speed and the upset pressure. The results obtained are as follows： Heat transfer to the specimens and the intermediate material during friction process was made clear; The operational conditions such as the rotation number of the intermediate material and the friction pressure to reach the liquidus in the interface could be estimated; Further, as the overhang length near the interface is well related to the joint efficiency, we tried to obtain the operational conditions by numerical analysis to acquire a certain length of the overhang length near the interface.     

Numerical investigation of heat transfer in upward flows of supercritical water in circular tubes and tight fuel rod bundles

Heat transfer in upward flows of supercritical water in circular tubes and in tight fuel rod bundles is numerically investigated by using the commercial CFD code STAR-CD 3.24. The objective is to have more understandings about the phenomena happening in supercritical water and for designs of supercritical water cooled reactors. Some turbulence models are selected to carry out numerical simulations and the results are compared with experimental data and other correlations to find suitable models to predict heat transfer in supercritical water. The comparisons are not only in the low bulk temperature region, but also in the high bulk temperature region. The two-layer model (Hassid and Poreh) gives a better prediction to the heat transfer than other models, and the standard k– high Re model with the standard wall function also shows an acceptable predicting capability. Three-dimensional simulations are carried out in sub-channels of tight square lattice and triangular lattice fuel rod bundles at supercritical pressure. Results show that there is a strong non-uniformity of the circumferential distribution of the cladding surface temperature, in the square lattice bundle with a small pitch-to-diameter ratio (P/D). However, it does not occur in the triangular lattice bundle with a small P/D. It is found that this phenomenon is caused by the large non-uniformity of the flow area in the cross-section of sub-channels. Some improved designs are numerically studied and proved to be effective to avoid the large circumferential temperature gradient at the cladding surface.     

巷道通风预测的非定常解析系统的开发

研究开发了一种用于地下通风巷道网络的非定常预测解析系统,解析系统包含了巷道外气候的季节变化及巷道壁的围岩与巷道内气流的热传递关系对预测解析的影响因素。采用差分法计算巷道围岩内的温度分布,在自然通风条件下,使用某隧道口的一年间季节变化的实测数据,对一地下通风巷道网络模型进行了预测解析。解析结果表明,该预测解析系统能时时刻刻同时详细地计算地下通风巷道的风量,温度,湿度等通风参数,解析得到的有关通风参数是合理的。     

A Dual Anti-Inflammatory and Anti-Proliferative 3-Styrylchromone Derivative Synergistically Enhances the Anti-Cancer Effects of DNA-Damaging Agents on Colon Cancer Cells by Targeting HMGB1-RAGE-ERK1/2 Signaling

The current anti-cancer treatments are not enough to eradicate tumors, and therefore, new modalities and strategies are still needed. Most tumors generate an inflammatory tumor microenvironment (TME) and maintain the niche for their development. Because of the critical role of inflammation via high-mobility group box 1 (HMGB1)–receptor for advanced glycation end-products (RAGE) signaling pathway in the TME, a novel compound possessing both anti-cancer and anti-inflammatory activities by suppressing the HMGB1-RAGE axis provides an effective strategy for cancer treatment. A recent work of our group found that some anti-cancer 3-styrylchromones have weak anti-inflammatory activities via the suppression of this axis. In this direction, we searched such anti-cancer molecules possessing potent anti-inflammatory activities and discovered 7-methoxy-3-hydroxy-styrylchromone (C6) having dual suppressive activities. Mechanism-of-action studies revealed that C6 inhibited the increased phosphorylation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) under the stimulation of HMGB1-RAGE signaling and thereby suppressed cytokine production in macrophage-like RAW264.7 cells. On the other hand, in colorectal cancer HCT116 cells, C6 inhibited the activation of ERK1/2, cyclin-dependent kinase 1, and AKT, down-regulated the protein level of XIAP, and up-regulated pro-apoptotic Bax and caspase-3/7 expression. These alterations are suggested to be involved in the C6-induced suppression of cell cycle/proliferation and initiation of apoptosis in the cancer cells. More importantly, in cancer cells, the treatment of C6 potentiates the anti-cancer effects of DNA-damaging agents. Thus, C6 may be a promising lead for the generation of a novel class of cancer therapeutics.     

Molecular cloning of homologs of RAS and RHO1 genes from Cryptococcus neoformans

We cloned and sequenced homologs of RAS(CnRAS) and RHO1(CnRHO1) genes from Cryptococcus neoformans. The proteins encoded by the CnRAS and CnRHO1 genes contained 216 and 197 amino acids, respectively. The deduced amino acid sequence of the CnRAS gene shared a high degree of sequence identity with the Ras proteins in other fungal species: Coprinus cinereus(76%), Lentinula edodes(74%), Saccharomyces cerevisiae RAS2(72%), and Schizosaccharomyces pombe(68%). The deduced amino acid sequence of the CnRHO1 gene shared a high degree of sequence identity with the Rho1 proteins in other fungal species: Candida albicans(78%), S. pombe(77%) and S. cerevisiae(76%). The deduced proteins contained GTP‐binding and GTP‐hydrolysis domains, and the prenylation site that are conserved among the small G protein superfamily. The synthetic peptides that contained the C‐terminal amino acid sequence of the CnRas and CnRho1 proteins were geranylgeranylated. The DDBJ/EMBL/GenBank Accession Numbers of the CnRAS and CnRHO1 genes are AB017640 and AB017639, respectively. Copyright © 1999 John Wiley & Sons, Ltd.