小型CPL用高性能烧结毛细芯的研制

采用粉浆浇注工艺和氢气还原烧结工艺研制小型CPL用烧结镍毛细芯，通过优选粉浆液固比、添加剂的种类与数量、浆料pH值等参数制备了符合设计要求的烧结毛细芯。测试了毛细芯孔径、孔隙分布特征、孔径分布、孔隙度、渗透率等性能参数，分析了烧结气氛、温度、时间对毛细芯性能的影响。试验结果表明，研制的毛细芯孔隙度在68％以上，孔隙尺寸约4μm，渗透系数在10^-12～10^-13m^2之间。     

基于要素分离的用户界面安全性设计

提出了一种分离用户界面要素的方法来提高用户界面设计的有效性和可靠性。分析了用户界面设计中使用该方法的优点和如何对用户界面要素进行分离。重点讨论基于该方法的用户界面安全性设计。     

Using group communication to monitor web-based group learning

Abstract  In a web group-learning environment, students must communicate with other group members on the Internet to accomplish group projects and share knowledge. Communication is likely to affect performance and so analysing the relationship between communicative relationships and group performance may help teachers to monitor groups effectively. Certain tasks are necessary to perform such an analysis — recording group communication, extracting communication relationships and determining the relationship between group communication and group performance. This study developed a method for determining relationships and rules for predicting performance to enable teachers to take act appropriately according to the predicted performance of the group. Four group performance indicators are considered — average grades within a group, project grade, frequency of resource-sharing and drop-out rate. Experimental results are presented, concerning the application of the methodology to a web class of 706 students, divided into 70 groups. The experimental results show that group communication patterns significantly affect group performance.     

Design and Implementation of Fuzzy Sliding-Mode Controller for a Wedge Balancing System

In this paper, we address the design and implementation of fuzzy sliding-mode controller for balancing a wedge system. At first, we examine the mathematical model of the wedge balancing system. The dynamic system is complex and ill defined; hence we propose the fuzzy sliding-mode control (FSMC) method to achieve the control objective. The proposed control method enhances the ability of fuzzy logic control so that the minimal number of fuzzy inference rules is systematically obtained even the plant parameters are unknown. Both computer simulations and real-time experiments are exploited to demonstrate the validity and feasibility of the developed control scheme.     

实时专家系统中的时限推理问题

介绍了解决实时专家系统中最重要的一个问题即时限准推问题的多种方法，在此基础上，出了基于数值计算的３种快速推理算法；矩阵法、有向图网络法和类神经网络法。上述理论对建立实时专家系统具有重要的指导作用。     

一点对多点通讯在卫星测试无线转发系统中的应用

分析了卫星测试无线转发中一点对多点通讯系统中的关键性技术：包括硬件连接、通讯方式及有关技术，并给出了具体方案。     

七号信令系统中TUP和ISUP协议的兼容设计

文中从信令消息，消息参数，信令过程和时限四个方面，对ＴＵＰ和ＩＳＵＰ的协议进行了分析比较，提出了一种兼容ＴＵＰ和ＩＳＵＰ的功能模块ＩＴＵＰ。这种兼容设计方法大大简休了软件编制，提高了软件系统的集成度和代码的可重用性，不仅满足了当前电话网对ＴＵＰ的要求，而且可以方便地向ＩＳＤＮ过渡。     

某型内燃机闭环控制减振的仿真研究

内燃机自身的振动是重型军用车辆主要的振动和噪声源,对其进行有效的振动控制十分重要.但由于内燃机系统结构的复杂性,研究其振动和噪声控制比较困难.针对某型内燃机系统,采用Matlab软件的Simulink工具,建立了整个系统的动力学仿真模型,并分别对该模型进行简谐、白噪声信号扰动下的减振控制研究,控制方法采用闭环数字PI策略.系统输出转矩和转速的曲线结果表明减振具有明显的效果.     

厚壁容器圆柱壳开孔应力集中问题(Ⅱ)

根据厚壁圆筒形压力容器开孔应力集中系数的一般表达式，利用正交函数展开的方法，将厚壁圆柱壳的开孔应力问题简化为求解一组无穷代数方程组问题为说明复变函数分析方法的适用性，给出了圆筒形压力容器在自由边界条件下，开圆孔和椭圆孔应力集中系数的数值结果