Genetic algorithms: concepts and applications [in engineeringdesign]

This paper introduces genetic algorithms (GA) as a complete entity, in which knowledge of this emerging technology can be integrated together to form the framework of a design tool for industrial engineers. An attempt has also been made to explain “why” and “when” GA should be used as an optimization tool     

MOS控制晶闸管的三重扩散工艺研究

本文对ＭＣＴ的核心工艺－三重扩散工艺进行了详细研究。通过ＳＵＰＲＥＭ－Ⅲ计算机工艺仿真，获得了三重扩散的工艺条件。     

Triangular ray-tube analysis of dielectric lens antennas

A new method of analysis for the radiation characteristics of dielectric lens antennas with arbitrary inner and outer surfaces is presented. The analysis is based on representing the feed illumination by a contiguous set of ray tubes and including the effects of surface reflections and ray divergence. Radiation patterns and the antenna gain are then computed by evaluating the closed-form expressions developed for the Kirchhoff's integral of the aperture fields. The validity of the analysis method has been demonstrated by comparing the computations with measured results of two different spherical lenses and a shaped lens configurations. The analysis method presented takes into account some of the practical aspects associated with lens design such as surface zoning to reduce the mass and surface matching to minimize the reflection loss     

结构振动控制中压电阻尼技术研究：（三）机敏约束层阻尼技术

给出了机敏约束阻尼概念，阐述了机敏约束层阻尼系统特征，分析了结构设计和系统建模方法。以典型梁系统为例，比较了被动约束阻尼技术和机敏约束层阻尼技术减振效果。结果表明；机敏约束层阻尼控制技术是一种更为有效的振动控制方法。最后，提出了今后重点研究问题。     

高功率激光焊接光致等离子体的检测

系统地归纳了高功率激光焊接过程中光致等离子体的声、光、电、热等四种特征信号，综述了国外在等离子体信号检测方面的试验方法及研究进展，分析了未来的发展趋势     

Reflection of Surface Plasmon Polaritons by a Corner Reflector of Negative Index Materials

A novel type of corner reflector for the reflection of surface plasmon polariton (SPP) is proposed. The reflector consists of two layers of compensatory media whose permittivity and permeability take opposite signs to that of the corresponding layer of the SP waveguide. By rigorously solving Maxwell's equations, the reflected SPP is proved to exist. The transverse wave vector of the reflected SPP is always antiparallel to that of the incident SPP and no phase retardation is introduced.     

Control of the block copolymer morphology in templated epoxy thermosets

It has been found that by the addition of low concentrations of an amphiphilic block copolymer to an epoxy resin, novel disordered morphologies can be formed and preserved through curing. This article will focus on characterizing the influence of the block copolymer and casting solvent on the templated morphology achieved in the thermoset sample. The ultimate goal of this work is to determine the parameters that would control the microphase morphology produced. Epoxy resins blended with a series of amphiphilic block copolymers based on hydrogenated polyisoprene (polyethylene-alt-propylene or PEP) and polyethylene oxide (PEO), specifically, were investigated. In this article, the cure-induced order–order phase transition from the spherical to wormlike micelle morphology will also be discussed. It is proposed that the formation of the wormlike micelle structure from the spherical micelle structure is similar to the phase transition behavior that occurs in dilute block copolymer solutions as a function of the influence of the solvent on micelle morphology. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 3338–3348, 2007     

碳纳米管及其批量制备研究进展

从碳纳米管的优异性能和应用出发,综述了碳纳米管的制备方法以及我国目前在碳纳米管研究中面临的问题;分析了碳纳米管产业化对的我国纳米技术产业化发展的积极意义,特别介绍了清华-南风纳米粉体产业化工程中心开发的、具有我国自主知识产权的纳米聚团流态化技术。     

p+209Bi核反应微观数据的理论计算

利用光学模型、激光模型、蒸发模型及扭曲波玻恩近似理论,对入射能量从阈能到300MeV,p+²⁰⁹Bi的中子反应截面、剩余核截面、出射粒子的多重数进行了理论计算及分析,并将计算结果与实验数据进行了比较.同时得到一组能量到50?0MeV与实验数据符合很好的光学势参数.