Hole Doping Mechanism in Bismuth Cuprates

The role of oxygen for the hole doping has been investigated for single-phased (Bi,Pb)₂Sr₂Ca₂Cu₃O. _z Defects introduced by oxygen have been clarified to be interstitial atoms by pycnometric density measurements. The c axis decreases and the modulation periods along the b axis also decrease with increasing oxygen content in the crystal. It is likely that extra oxygen ions exist between the BiO double layers and those oxygen ions are responsible for the modulation. Samples with oxygen content ranging from 9.99 to 10.18 showed superconductivity. The critical temperature T _c , exhibited a maximum value (109 K) at 10.07 oxygen atoms in the formula unit, which coincided with the average Cu valence of 2.13. The data indicated that hole formation was governed by oxygenation reaction in this system.     

Triple‐junction effect and its electric field relaxation in three dielectrics

This paper analyzes the electric field distribution near a wedge‐like edge in arrangements consisting of three dielectrics using analytical and numerical methods. The electric potential behaves exponentially as rⁿ (r is the distance from the edge) near the edge, leading to an infinitely high field with decreasing r for all cases. The value of the analytically derived exponent n agreed well with that obtained from the numerical field calculations. It has also been demonstrated that rounded contact of the spacer with a zero contact angle can make the electric field constant without showing an exponential rise near the edge. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(1): 1– 8, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20670     

CO2气体保护的激光焊接12mm厚低碳钢板

采用CO2 作为保护气体消除大熔深激光焊接低碳钢时易发生的气孔问题 ,并对比研究了CO2 和Ar气保护条件下 12mm厚低碳钢板激光焊缝的组织和韧性。焊接试验利用 4kWNd :YAG激光器 ,采用双面深熔焊的方法 ,焊接条件为 4kW激光功率和0 .3 ,0 .5m/min的焊接速度。冲击试验采用一种自行设计的带侧面缺口的三缺口冲击试样 ,以保证断裂全部发生在焊缝。结果表明 ,利用CO2 作保护气体焊接低碳钢板 ,可以有效消除大熔深激光焊接时的气孔问题 ,并获得比Ar气保护下硬度较低 ,冲击韧性高的焊缝。研究工作为解决大功率激光深熔焊时容易发生的气孔问题提供了一条有效途径     

Identification of chemical oviposition stimulants from rice grain forSitophilus zeamais motschulsky (Coleoptera,Curculionidae)

Chemical components stimulating oviposition bySitophilus zeamais in rice grain were isolated from rice bran and were found to be a mixture of ferulates, diglycerides, and free sterols. Oviposition preference of the species can be induced by synergistic action of these compounds.     

Synthesis of the Orthorhombic Phase of ZrO2

Single-phase orthorhombic ZrO₂ was prepared by quenching from high temperature and high pressure. The lattice parameters are a₀=0.5042, b₀=0.5092, and c₀=0.5257 nm; the calculated density is 6.09 Mg·m⁻³. This phase is metastable under atmospheric pressure and reverts to the monoclinic phase either on heating above 300°C or when it is ground in a mortar.     

Fast agglomerative hierarchical clustering algorithm using Locality-Sensitive Hashing

The single linkage method is a fundamental agglomerative hierarchical clustering algorithm. This algorithm regards each point as a single cluster initially. In the agglomeration step, it connects a pair of clusters such that the distance between the nearest members is the shortest. This step is repeated until only one cluster remains. The single linkage method can efficiently detect clusters in arbitrary shapes. However, a drawback of this method is a large time complexity of O(n ²), where n represents the number of data points. This time complexity makes this method infeasible for large data. This paper proposes a fast approximation algorithm for the single linkage method. Our algorithm reduces the time complexity to O(nB) by rapidly finding the near clusters to be connected by Locality-Sensitive Hashing, a fast algorithm for the approximate nearest neighbor search. Here, B represents the maximum number of points going into a single hash entry and it practically diminishes to a small constant as compared to n for sufficiently large hash tables. Experimentally, we show that (1) the proposed algorithm obtains clustering results similar to those obtained by the single linkage method and (2) it runs faster for large data than the single linkage method. Hisashi Koga received the M.S. and Ph.D. degree in information science in 1995 and 2002, respectively, from the University of Tokyo. From 1995 to 2003, he worked as a researcher at Fujitsu Laboratories Ltd. Since 2003, he has been a faculty member at the University of Electro-Communications, Tokyo (Japan). Currently, he is an associate professor at the Graduate School of Information Systems, University of Electro-Communications. His research interest includes various kinds of algorithms such as clustering algorithms, on-line algorithms, and algorithms in network communications. Tetsuo Ishibashi received the M.E. degree in information systems design from the Graduate School of Information Systems at the University of Electro-Communications in 2004. Presently, he is a system engineer at Fujitsu Broad Solution & Consulting Inc. Toshinori Watanabe received the B.E. degree in aeronautical engineering in 1971 and the D.E. degree in 1985, both from the University of Tokyo. In 1971, he worked at Hitachi as a researcher in the field of information systems design. His experience includes demand forecasting, inventory and production management, VLSI design automation, knowledge-based nonlinear optimizer, and a case-based evolutionary learning system nicknamed TAMPOPO. He also engaged in FGCS (Fifth Generation Computer System) project of Japan and developed a new hierarchical message-passing parallel cooperative VLSI layout problem solver that ran on PIM (Parallel Inference Machine) in 1991. Since 1992, he has been a professor at the Graduate School of Information Systems, University of Electro-Communications, Tokyo, Japan. His areas of interest include media analysis, learning intelligence, and the semantics of information systems. He is a member of the IEEE.     

Sub-millimeter-long carbon nanotubes repeatedly grown on and separated from ceramic beads in a single fluidized bed reactor

A semi-continuous fluidized-bed process is reported which rapidly converts acetylene into carbon nanotubes (CNTs). Catalysts are first immobilized on ceramic beads and CNTs are then grown on the beads and then separated from them in a repetitive process accomplished within a single reactor simply by switching gases at a fixed temperature. CNTs of 6–10 nm diameter, three walls on average, 0.4 mm length and 99 wt.% purity were synthesized at an yield of over 70% in a reactor residence time shorter than 0.3 s. The easy and efficient production of such CNTs with in situ separation from the catalysts may accelerate the development of CNT-based nanotechnology industries.     

An FPGA implementation of hard‐wired sequence control system based on PLC software

Although a programmable logic controller (PLC) has been widely adopted for the sequence control of industrial machinery, its performance does not always satisfy the recent requirements in large and highly responsive systems. With the state‐of‐the‐art field programmable gate array (FPGA) technology, it is possible to implement a control program with hard‐wired logic for higher response and reduced implementation cost/space. This approach is also worthwhile for transmigration of legacy PLC software into forthcoming FPGA‐based control hardware. This study presents a systematic method to implement a hard‐wired sequence control from PLC software. PLC instructions are converted into VHDL codes, and then implemented as logic circuit with various peripheral functions. Productive PLC programs were examined with Mitsubishi Electric FX2N PLC and Altera Stratix II FPGA, and were shown to fit into a common FPGA chip. A straightforward Sequential design was estimated to be 184 times faster than PLC, while a performance‐oriented Flat design was estimated to be 44 times faster than Sequential design (i.e., 8050 times faster than PLC). A practical perfect layer winder system was actually built and successfully operated with our FPGA control board, whose logic design was implemented with our tools. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

新一代超小型DIP-IPM

为了满足空调、洗衣机、冰箱等白色家电对高效、高性能的需要,三菱电机开发了新一代超小型第四代(Ver.4)双列直插封装的智能功率模块(Dual-In-linePackageIntelligentPowerModule,简称DIP-IPM)。本文首先分析了第四代超小型DIP-IPM内部电路的构成和功能,然后详细介绍了第四代DIP-IPM生产过程中的关键技术,包括无铅化、高热传导性绝缘片、chip-to-chip导线直接连接以及ASIC技术,最后与第三代(Ver.3)DIP-IPM进行了比较。     

A reinforcement learning with switching controllers for a continuous action space

Reinforcement learning (RL) attracts much attention as a technique for realizing computational intelligence such as adaptive and autonomous decentralized systems. In general, however, it is not easy to put RL to practical use. This difficulty includes the problem of designing a suitable action space for an agent, i.e., satisfying two requirements in trade-off: (i) to keep the characteristics (or structure) of an original search space as much as possible in order to seek strategies that lie close to the optimal, and (ii) to reduce the search space as much as possible in order to expedite the learning process. In order to design a suitable action space adaptively, in this article, we propose a RL model with switching controllers based on Q-learning and an actor-critic to mimic the process of an infant’s motor development in which gross motor skills develop before fine motor skills. Then a method for switching controllers is constructed by introducing and referring to the “entropy.” Further, through computational experiments by using a path-planning problem with continuous action space, the validity and potential of the proposed method have been confirmed.