动态包过滤防火墙规则优化研究

传统的静态防火墙是根据预先规定的特定的过滤规则对访问网络的数据包进行简单过滤,难以防范越来越复杂动态的网络攻击,同时随着静态过滤规则数目的不断增大,规则的管理也越来越复杂。而动态包过滤防火墙具有传统防火墙的功能,更能提供对运输层完整的控制能力,简化了对规则集的匹配工作,提高了网络通信速率。文章对动态包过滤防火墙的工作原理和过滤规则的优化进行了研究,能在不影响网络安全访问的前提下,提高过滤规则表的管理效率。     

一种并行冗余遥控锁定投放控制系统

以海上无人演练战场等复杂环境下实现对大负载作战单元的遥控布放为需求,提出了一种包含短波、超短波和卫星无线信道,以及本地端手动控制的多并行冗余锁定投放控制系统.设计了一种新型锁定投放装置,使用恒流源驱动的直流减速电机推动锁闩执行布放任务,具有功耗小、负载大等优点;在锁定投放装置的控制器中并行集成了以上几种投放控制接口,能以互为备份的方式执行任意种或多种投放控制指令,提高了系统的鲁棒性.该锁定投放控制系统已多次执行海上任务,工作稳定可靠.     

基于TimeMark技术的网络级数据容灾设计与实施

建立存储虚拟化的网络级容灾系统,要注意数据的不一致或不完整的问题,因为由此可能导致系统无法启动或恢复。利用TimeMark技术建立容灾系统,存储设备可以为数据副本生成多个快照,记录数据副本在不同时刻的状态,可以有效地避免渐变式灾难带来的数据损坏,从而保障数据一致性和可用性。     

Dynamics and genetic fuzzy neural network vibration control design of a smart flexible four-bar linkage mechanism

In this paper, a dynamic modeling method and an active vibration control scheme for a smart flexible four-bar linkage mechanism featuring piezoelectric actuators and strain gauge sensors are presented. The dynamics of this smart mechanism is described by the Discrete Time Transfer Matrix Method of Multibody System (MS-DTTMM). Then a nonlinear fuzzy neural network control is employed to suppress the vibration of this smart mechanism. For improving the dynamic performance of the fuzzy neural network, a genetic algorithm based on the MS-DTTMM is designed offline to tune the initial parameters of the fuzzy neural network. The MS-DTTMM avoids the global dynamics equations of the system, which results in the matrices involved are always very small, so the computational efficiency of the dynamic analysis and control system optimization can be greatly improved. Formulations of the method as well as a numerical simulation are given to demonstrate the proposed dynamic method and control scheme.     

基于Virtools的虚拟现实技术及在特种设备教学中的应用

本文以电梯为研究对象,运用虚拟现实技术建立电梯虚拟样机,开发了一种电梯零部件识别系统用于电梯司机的考核。现行的考核方式存在过程繁琐、成绩统计困难等问题,就这些问题提出了合理的解决方案,并将方案应用于开发的系统中。该系统是虚拟现实技术在特种设备领域的全新应用,构建的虚拟电梯完整地呈现了真实的电梯,而且可以从多角度观察其结构的每个细节,方便教学与考核。系统结合SolidWorks、3Dmax、Virtools等软件,以触摸选择为主要的操作方式,具有优良的操作性与交互性,且投资少、开发周期短。     

基于单片机的皮带秤变频调速控制仪的设计与实现

介绍了皮带秤调速控制仪系统实现的原理和方法,提出了在皮带秤调速控制仪的动态跟踪问题,采用模糊-数字PID复合控制算法,既可计量也可以实时跟踪控制产量。实践表明,该控制方法理想地解决了实时跟踪问题,取得了较好的控制效果。     

IC封装模流道平衡CAE应用

分析了热固性塑料的流动行为特点和IC封装充填过程中料流对金丝的冲击状态。用CAE软件Moldflow公司的MPA对流道的平衡进行分析模拟 ,优化浇注系统 ,为提高IC封装产品合格率寻找一种简便有效的途径。     

基于数控加工的三次Bzier曲线变步长直线插补新算法

本文给出了基于数控加工的三次B啨ｚｉｅｒ曲线变步长直线插补算法 ,和算法在程序上的实现。即在德卡斯特里奥算法和细化的基础上 ,引进B啨ｚｉｅｒ曲线起点切矢与Ｘ轴夹角λ这个参数 ,通过控制相邻两段B啨ｚｉｅｒ曲线起始切矢与Ｘ轴夹角λ的夹角差△λ在恒定范围内 ,对德氏点进行取舍 ,从而得到一组适合于数控加工的B啨ｚｉｅｒ曲线插补点。     

Synthesis,Micellization, and Surface Activity of Novel Linear-Dendritic Carboxylate Surfactants

Two generations of novel linear-dendritic carboxylate surfactants C₁₈-G₁-(COONa)₂ and C₁₈-G₂-(COONa)₄ have been synthesized by the divergent method and their structures are characterized by ¹H Nuclear Magnetic Resonance and Infrared analysis. The electrical conductivity measurement is used to measure the Krafft temperatures of C₁₈-G₁-(COONa)₂ and C₁₈-G₂-(COONa)₄, which are much smaller than those of the corresponding conventional surfactant sodium stearate. The markedly enhanced solubility of two linear-dendritic surfactants is ascribed to the high hydrophilicity of surfactant headgroups induced by the carboxylate and ester groups. The critical micelle concentration (CMC) values obtained from both the electrical conductivity and surface tension measurements indicate that the micellizations of linear-dendritic surfactants become favorable with the increase in the number of the surfactant headgroup. However, the surface activity parameters including the surface tension at the CMC, maximum surface excess, and minimum surface area reveal that C₁₈-G₁-(COONa)₂ exhibits greater efficiency in absorbing at the air/water interface compared to C₁₈-G₂-(COONa)₄, owing to their different steric repulsions of the surfactant headgroups. In addition, C₁₈-G₁-(COONa)₂ and C₁₈-G₂-(COONa)₄ have higher emulsifying ability than the conventional surfactants sodium stearate and sodium octadecyl sulfate.     

汽车稳定杆组织与疲劳性能研究

对28Mn6钢制造的汽车稳定杆，分别采用整体感应加热-整体淬火、连续感应加热淬火两种不同工艺热处理，并进行了台架疲劳寿命试验。采用光镜分析了不同稳定杆的金相组织，用扫描电镜分析了早期疲劳断裂的稳定杆断口形貌。结果表明，获得细小的高韧性索氏体组织是保证良好疲劳寿命的关键，稳定杆喷丸表面质量、游离铁素体也是影响疲劳性能的重要因素。