文献与摘要（103）

PCB制造商为改进客户服务和下降成本,自动地处理销售订单 自动化是源于制造业生产中,现也应用于经营管理。在许多先进的PCB制造企业已经把订单管理列入ERP系统,摆脱旧式的手工处理方式,以实现高效率的生产经营管理和为客户服务。文章叙述了在20世纪时的纸张文件管理状况,目前电子化自动管理带来的高效和低成本优越性,以及自动管理需配置的硬件与软件条件。     

VXI产品选购小常识

怎样选购VXI产品,仍然是广大用户关心的问题,加之资料不足、信息不通更造成选购时的困难。 VXI规范鼓励多家生产同类的VXI模块化仪器,既便于用户根据需要选购适用的规格,也便于货比三家,使用户对同一规格的VXI仪器可选价格最好或服务最好的产品。用户选购VXI产品当然应该根据自己的需要(品种、性能、指标、尺寸等等)和可能(经费)。通常有三种配置的方式,第一种是选择性能指     

科技故事演说家

凯文·布鲁克斯是一位1999年毕业于MIT的博士，他以自己独特的叙事技巧征服了观众——同时也帮助设计师和工程师们发明出更好的产品。     

Preparation of Silver—Coated Polystyrene Composite Particles

We report a feasible approach to the preparation of monodispersed metal-shell composite microspheres based on a combination of surface reaction and surface seeding techniques. The method was implemented for coating polystyrene (PS) spheres with silver shell having a variable thickness by controlling the amount of reagents in the reaction procedure. These composite spherical particles in dimensions of the submicrometer range may become attractive building blocks for the creation of metallo-dielectric photonic band gap materials when they are organized into crystals.     

Oeffner展宽器高倍率展宽脉冲的理论与实验研究

在理论上分析了Oeffner展宽器的色散特性，给出了展宽脉冲随Oeffner展宽器系统参数变化的关系．据此在实验上建立了一台Oeffner飞秒展宽器系统，将19fs的种子脉冲无色差展宽至605ps，测量结果与理论计算一致．     

带鳍通道性能的遗传算法优化

与光滑通道相比,带鳍通道有更高的传热系数,附加的鳍,极大地增强了通道的传热.然而,传热的增强又与压降的升高相关联,这又导致泵动力需求的增加,因此应该寻求对该系统的优化设计.该文的主要目的是,通过如下方式来精确地确定鳍的位置和尺寸:利用遗传算法实现最小压降时达到最优传热.鳍的每种布局作为问题(遗传算法中的一个个体)的一个解.通常,首先随机地产生一个初始种群,然后该算法在所有这些解中搜索,利用布局函数迭代出新解,最后得到鳍的优化设计.     

Two Typical Examples of Scaling Ionic Partition Scheme for Estimating Correlation Energy of A2 Type Molecules

Based on the calculation results of pair correlation energy contributions of the various electron pairs in Na2 and H2NNH2 systems and the application of the scaling ionic partition scheme for symmetrical A2 type systems, the total correlation energies of Na2 and H2NNH2 have been reproduced by using this simple scheme. The two results show that the absolute deviations are within an acceptable range of error, however, in this way, more than 90% of computational work can be saved. The most attractive result in present paper is that, in these two molecules the coefficients c1 and c2 in the estimation equation can be obtained by the proportion of correlation energy of A^- to that of A^ singlet system. Therefore, it is believed that the proposed ionic partition scheme for symmetrical A2 molecules would be very useful to estimate the correlation energies of large symmetrical molecules.