Processing network models of energy/environment systems

Processing networks are a variant of the standard linear programming network model which are especially useful for optimizing industrial energy/environment systems. Modelling advantages include an intuitive diagrammatic representation and the ability to incorporate all forms of energy and pollutants in a single integrated linear network model. Added advantages include increased speed of solution and algorithms supporting formulation. The paper explores their use in modelling the energy and pollution control systems in large industrial plants. The pollution control options in an ethylene production plant are analyzed as an example. PROFLOW, a computer tool for the formulation, analysis, and solution of processing network models, is introduced.

特权约束系统职责隔离问题研究

特权控制操作系统最重要的资源，需要应用职责隔离原则，确保特权安全．与现有研究不同，从特权隐式授权方面探讨对职责隔离的支持问题．通过分析特权来源，将特权定义分解为约束规则与执行规则，弥补了现有访问控制研究中对权限效果描述不足的缺陷．两类规则间的逻辑推导说明授权间的推导关系，即特权问存在隐式授权，可能不满足职责隔离要求．利用授权推导关系图准确而全面地反映了特权机制的所有隐式授权．从特权的职责隔离属性，及职责隔离对特权的机制要求两方面探讨上层职责隔离需求与底层特权控制实施的一致性问题．以目前广泛应用的POSIX权能机制为例，给出其形式化模型BMPS模型的定义，指出该机制支持职责隔离存在的问题，并对该机制进行了改进，给出满足职责隔离要求的特权策略实施方案．

Morphology, thermal behavior, and mechanical properties of PA6/UHMWPE blends with HDPE-g-MAH as a compatibilizing agent

A functionalized high-density polyethylene (HDPE) with maleic anhydride (MAH) was prepared using a reactive extruding method. This copolymer was used as a compatibilizer of blends of polyamide 6 (PA6) and ultrahigh molecular weight polyethylene (UHMWPE). Morphologies were examined by a scanning electron microscope. It was found that the dimension of UHMWPE and HDPE domains in the PA6 matrix decreased dramatically, compared with that of the uncompatibilized blending system. The size of the UHMWPE domains was reduced from 35 mu m (PA6/UHMWPE, 80/20) to less than 4 mu m (PA6/UHMWPE/HDPE-g-MAH, 80/20/20). The tensile strength and Izod impact strength of PA6/UHMWPE/HDPE-g-MAH (80/20/20) were 1.5 and 1.6 times as high as those of PA6/UHMWPE: (80/20), respectively. This behavior could be attributed to chemical reactions between the anhydride groups of HDPE-g-MAH and the terminal amino groups of PA6 in PA6/UHMWPE/HDPE-g-MAH blends. Thermal analysis was performed to confirm that the above chemical reactions took place during the blending process. (C) 2000 John Wiley & Sons, Inc.

基于C/S模式的多水下机器人仿真平台网络通信研究

文章研究了基于客户端/服务器(C/S)模式的多水下机器人仿真平台中网络通信的关键技术。文章介绍了该仿真平台的结构和功能,分析了仿真平台的信息流向和通信特点,在此基础上,提出了适合该仿真平台应用的网络通信协议和时钟同步方案,并详细讨论了Windows和QNX两种不同操作系统上的应用程序之间进行网络通信的实现方法。

客户／服务器环境下的OS／22·1操作系统

ＯＳ／２２·１是当今客户／服务器计算模式的首选操作系统之一。本文对ＩＢＭＯＳ／２２·１操作系统所具备的，对客户／服务器计算模式的各种支持功能作了详细的介绍。

Design of super-resolution filters with a Gaussian beam in optical data storage systems

Super-resolution filters based on a Gaussian beam are proposed to reduce the focusing spot in optical data storage systems. Both of amplitude filters and pure-phase filters are designed respectively to gain the desired intensity distributions. Their performances are analysed and compared with those based on plane wave in detail. The energy utilizations are presented. The simulation results show that our designed super-resolution filters are favourable for use in optical data storage systems in terms of performance and energy utilization.

The design structure system - A method for managing the design of complex systems

Systems design involves the determination of interdependent variables. Thus the precedence ordering for the tasks of determining these variables involves circuits. Circuits require planning decisions abut how to iterate and where to use estimates. Conventional planning techniques, such as critical path, do not deal with these problems. Techniques are shown in this paper which acknowledge these circuits in the design of systems. These techniques can be used to develop an effective engineering plan, showing where estimates are to be used, how design iterations and reviews are handled, and how information flows during the design work.