Analysis of magnetic bearing using inductive levitation by relative motion between magnet and conductor

In chemical plants, an anticorrosion magnetic drive pump is commonly used to deliver corrosive chemical liquids because of its high anticorrosion performance. However, when bubbles enter the chemical pump and accumulate between the shaft and the bearing, the shaft is often broken by thermal shock. The magnetic bearing which holds the rotor in noncontact has the advantage of avoiding thermal shock and keeping the rotor in a stable state by restoring force induced from the eddy current in the conductor. A model of magnetic bearing was analyzed using the three‐dimensional finite element method. In this model, a restoring force of 68.6 N and a braking torque of 8.7 N‐m were found. The locus of the rotation axis was also estimated using a radial load and a drag coefficient. The rotor may be located inside the movable range. ©2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(4): 80–87, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20652     

Formation of uniaxially strained SiGe by selective ion implantation technique

Uniaxially strained SiGe layers were fabricated with a newly developed selective-ion-implantation technique. The SiGe layer was grown on the Si substrate, into which laterally selective ion-implantation with stripe pattern was carried out prior to the SiGe growth. A strain-relaxation of the SiGe layer was largely enhanced due to ion-implantation-induced defects selectively in the ion-implanted area while it was hardly enhanced in the neighboring unimplanted area. However, micro-Raman mapping and X-ray diffraction reciprocal space mapping measurements obviously revealed that the relaxed SiGe in the implanted area remarkably influenced a strain state of the neighboring strained SiGe in the unimplanted area, that is, the strain along the stripe line direction was highly relieved due to the stress caused by the neighboring relaxed SiGe while the strain in the direction perpendicular to the line was well maintained. As a result, highly asymmetric strain state, that is, uniaxial strain was realized, where 4 times different relaxation ratios in the two directions were observed. These results indicate that the selective-ion-implantation technique developed in this study has a high potential to realize uniaxially strained Si/Ge channel devices with high mobility.     

Detecting Unstable Periodic Orbits in Hyperchaotic Systems Using Subspace Fixed-Point Iteration

<正>We present a numerical method for efficiently detecting unstable periodic orbits(UPO's)embedded in chaotic attractors of high-dimensional systems.This method,which we refer to as subspace fixed-point iteration, locates fixed points of Poincare maps using a form of fixed-point iteration that splits the phase space into appropriate subspaces.In this paper,among a number of possible implementations,we primarily focus on a subspace method based on the Schmelcher-Diakonos(SD)method that selectively locates UPO's by varying a stabilizing matrix,and present some applications of the resulting subspace SD method to hyperchaotic attractors where the UPO's have more than one unstable direction.     

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.     

The number distribution of complex shear modulus of single cells measured by atomic force microscopy

The viscoelastic properties of a large number of mouse fibroblast NIH3T3 cells (n?130) were investigated by combining atomic force microscopy (AFM) with a microarray technique. In the experiments, the cells were arranged and cultured in the wells of a microarray substrate, and a force modulation mode experiment was used to measure the complex shear modulus, G*, of individual cells in a frequency range 0.5–200 Hz. The frequency dependence of G* of the cells exhibited a power-law behavior and similar frequency dependencies have been observed in several cell types cultured on flat substrates. This indicated that the NIH3T3 cells cultured in the wells of a microarray have analogous structural organization to those cells cultured on flat substrates. The number distribution of both the storage and loss moduli of G* fitted well to a log-normal distribution function, whereas the power-law exponent estimated by a power-law structural damping model showed a normal distribution function. These results showed that combining AFM with a microarray technique was a suitable approach for investigating the statistics of rheological properties of living cells without the requirement of cell surface modification.     

Development of the Design Codes Grounded on the Performance-Based Design Concept in Japan

This paper traces the recent introduction of performance-based design (PBD) into Japanese design codes (especially geotechnical design codes) and describes the distinguishing characteristics of PBD codes. An overview is provided for source documents that initiated the concept of performance-based design, and consideration is given to the impact of the WTO/TBT Agreement and Japanese government policies on this issue. Three design codes are introduced to explain the development of PBD codes in Japan: JGS4001-2004 ‘Principles for Foundation Design Grounded on a Performance-Based Design Concept’ (Geocode 21); Technical Standards for Port and Harbor Facilities (TSPHF); and Specifications for Highway Bridges (SHB). The first one is a model code established by JGS, whereas the latter two are regulatory design codes used in practice. Performance-based design is now recognized as the most important concept in code drafting and the majority of design codes will introduce this concept at least partially. Thus, PBD is a key concept for understanding the current Japanese design codes.     

The effect of fouling on nucleate pool boiling of small wires

Pool boiling experiments with small diameter wires were conducted in earth gravity and microgravity conditions. Bare wire and fouled wire with a scale deposition of calcium carbonate was used. The wettability on the scale wire was higher than that on the bare wire. Though more vigorous bubbling was observed on the scale wire when compared to that on the bare wire at the same heat flux, the boiling curve for the scale wire was approximately the same as that on the bare wire. However, the critical heat flux (CHF) on the scale wire was higher than that of the bare wire. On the scale wire, the departure diameter of bubbles was relatively smaller than that on the bare wire. The smaller diameter of bubbles detaching from the scale wire is considered to be due to the high wettability and high nucleation site density. As the result, the coalescence of bubbles near the wire was prevented, and the CHF was delayed and increased on the scale wire when compared to that on the bare wire. © 2004 Wiley Periodicals, Inc. Heat Trans Asian Res, 33(5): 316–329, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20016     

基于FIPA-Agent的变电站故障诊断系统研究

通过引入Multi-Agent系统,提出了一个完全符合FIPA标准的基于多Agent的变电站故障诊断系统体系,该体系参与的Agent包括:系统管理Agent、服务管理Agent、界面管理Agent、故障监测Agent、故障诊断Agent和故障决策Agent。在此基础上,提出了基于JADE中间件的变电站故障诊断MAS系统实现模型,最后给出了一个基于模糊融合的多Agent的变压器故障诊断实例,仿真结果表明该模型的合理性和可行性。     

Syntheses and characterization of new nickel coordination polymers with 4,4'-dipyridylsulfide. Dynamic rearrangements of one-dimensional chains responding to external stimuli: temperature variation and guest releases/re-inclusions

Crystal structures and dynamic rearrangements of one-dimensional coordination polymers with 4,4'-dipyridylsulfide (dps) have been studied. Reaction of Ni(NO(3))(2)·6H(2)O with dps in EtOH yielded [Ni(dps)(2)(NO(3))(2)] ·EtOH (1), which had channels filled with guest EtOH molecules among the four Ni(dps)(2) chains. This coordination polymer reversibly transformed the channel structure responding to temperature variations. Immersion of 1 in m-xylene released guest EtOH molecules to yield a guest-free coordination polymer [Ni(dps)(2)(NO(3))(2)] (2a), which was also obtained by treatment of Ni(NO(3))(2)·6H(2)O with dps in MeOH. On the other hand, removal of the guest molecules from 1 upon heating at 130 °C under reduced pressure produced a guest-free coordination polymer [Ni(dps)(2)(NO(3))(2)] (2b). Although the 2a and 2b guest-free coordination polymers have the same formula, they showed differences in the assembled structures of the one-dimensional chains. Exposure of 2b to EtOH vapor reproduced 1, while 2a did not convert to 1 in a similar reaction. Reaction of Ni(NO(3))(2)·6H(2)O with dps in acetone provided [Ni(dps)(NO(3))(2)(H(2)O)] ·Me(2)CO (4) with no channel structure. When MeOH or acetone was used as a reaction solvent, the [Ni(dps)(2)(NO(3))(2)] · (guest molecule) type coordination polymer, which was observed in 1, was not formed. Nevertheless, the reaction of Ni(NO(3))(2)·6H(2)O with dps in MeOH/acetone mixed solution produced [Ni(dps)(2)(NO(3))(2)]·0.5(MeOH·acetone) (5), which has an isostructural Ni-dps framework to 1.     

基于贝叶斯神经网络的风电短期功率预报研究

提高风电功率预报的准确率对电网的安全运行调度有着重要的意义。针对标准BP学习算法泛化能力不强的问题,设计了一种基于贝叶斯正则化算法修正权值的学习算法,用于风电的功率预测。仿真结果对比表明新的算法具有比标准BP算法和径向基神经网络具有更好的泛化能力,同时取得了良好的预测效果。