Dissipation and Decoherence in a Quantum Oscillator

The time development of the reduced density matrix for a quantum oscillator damped by coupling it to an ohmic environment is calculated via an identity of the Debye-Waller form. Results obtained some years ago by Hakim and the author in the free-particle limit⁽¹⁰⁾ are thus recovered. The evolution of a free particle in a prepared initial state is examined, and a previously published exchange^(5,9) is illuminated with figures showing no decoherence without dissipation. PACS number: 03.75.Ss     

基于虚拟仪器技术的高频地波雷达系统的实现

本文在比较了几种常用的虚拟仪器软硬件平台后,并根据高频地波雷达的应用特点和环境,提出了一种基于VXI仪器的硬件平台和基于基C Builder的软件编程环境.接着对该VXI机箱内的各模块功能进行简述.本文从软硬件的角度说明应用虚拟仪器技术到高频地波雷达中具有基于传统仪器技术所无法比拟的优势.     

基于“虚拟匹配”的PCB矩形Mark视觉快速检测

针对机器视觉中PCB(PrintedCircuitBoard,印刷电路板)矩形Mark的检测,提出一种“虚拟匹配”的快速检测方法。根据模板匹配的思想,引入一个“虚拟模板”,通过将虚拟模板内所有像素灰度值的累加和作为是否匹配的衡量标准来进行矩形Mark的检测。借助于粗细搜索的模板移动策略,使得检测过程速度快、精度高、抗噪能力强、对图像缩放可调、对检测图像旋转和光线亮度变化等不敏感,在实际应用中取得了满意的检测效果。     

The changing role of physical testing in vehicle development programmes

The role of physical testing in product development is changing due to the requirements for faster new product development, reduced tolerance of failures in the field and the emergence of computer aided engineering (CAE) technologies. To be used most effectively, testing must be seen as an integral part of the process for reducing risks associated with new product introductions. Quality function deployment (QFD) and failure modes and effects analysis (FMEA) can be used to establish effective test and development plans that integrate the use of virtual and physical testing. By effectively integrating virtual and physical test technologies significant improvements in product performance can be achieved within shorter times and with reduced development and manufacturing costs. The approach was illustrated by a process of reducing in-cab noise during the design of a new truck.     

Some Hardy Type Inequalities in R~n

Some Hardy type inequalities on the ball and its complementary set in the Euclidean space are established by using the Picone type identity and constructing suitable auxiliary functions.     

相空间路径积分中的Feynman规则和广义Ward恒等式

基于Green函数的相空间生成泛函,导出了广义正则Ward恒等式.指出无须作出相空间生成泛函中对正则动量的路径积分,即可求得树图近似下的Feynman规则.对场的拉氏量添加一个四维散度项后,场的传播子发生了改变.     

基于Taurus Workbench的亚微米n沟MOS器件关键工艺参数的优化

简要介绍了集成电路虚拟工厂系统Taurus Workbench。对亚微米n沟MOS工艺的特点进行了分析。在Taurus Workbench环境下进行亚微米n沟MOS器件关键工艺参数的优化，优化结果印证了新工艺条件对器件性能的改善。     

The Asymptotic Behavior of Certain Birth Processes

We describe a connection between discrete birth process and a certain family of multivariate interpolation polynomials. This enables us to compute all asymptotic moments of the birth process, generalizing previously known results for the mean and variance. Received July 15, 2004     

Micromechanical consideration of tensile crack behavior based on virtual internal bond in contrast to cohesive stress

A modified version of the virtual internal bond model (VIB) is presented. This involves the introduction of a R-bond restricting the relative rotation freedom of pairwise mass particle. Such a modification allows the VIB model to consider arbitrary values of the Poisson ratio. A linear elastic cohesive law considering both the R-bond and L-bond are assumed. The constitutive relationship is derived using the Cauchy–Born rules. The derived constitutive associates the bond stiffness with the Young’s modulus and Poisson ratio of materials. This gives the bond stiffness in terms of the Young’s modulus and Poisson ratio of materials.The modified VIB model is then used to analyze the tensile crack behavior. In contrast to the cohesive stress method, the deformation-governed concept will be used. The local materials failure is assumed to coincide with the reduction of the bond density due to the local deformation rather than by the local cohesive stress. A phenomenological relationship between the bond density and the deformation is established. The criterion which is applied to determined crack initiation and propagation is built into the constitutive model. As an example, the method is used to study the crack initiation and propagation behavior under tensile loading.     

基于TCP/IP协议的交换机集中网管接口的设计

介绍了采用TCP/IP协议的交换机集中网管接口的实现方法,设计了身份鉴别对话以保障交换机终端的远程接入安全.