加速冷却对控轧管线钢组织和性能的影响

采用两种管线钢材料,通过再结晶区和未再结晶区的五道次变形将试样厚度从60mm轧为8mm。热轧后的试样进行水幕冷却,然后分别放置于500℃和400℃的加热炉中随炉冷却以模拟卷取。结果表明,对于两种管线钢材料通过适当的冷却工艺都可以得到以针状铁素为主的组织。     

基于动态分区技术的Ad hoc混合式网络路由协议

在分析目前Ad hoc网络中常见的4种路由协议基础上,首次提出了应用计算几何中最小覆盖问题算法,并借鉴了GSM、CDMA移动通讯中的蜂窝位置管理技术,设计了一种基于动态分区的Ad hoc混合式网络路由协议:将Ad hoc网络中的各个节点进行动态地划分为若干个"移动蜂窝".在动态分区范围内使用先验式路由协议,缩小路由控制消息传播的范围.在动态分区间,通过查找每一个节点的归属分区寄存器,在动态分区间发现路由.实践证明,该混合式网络路由协议既减少路由协议的开销,也改善了时延特性.     

多代理框架下的电动汽车充电站协调控制

为了兼顾电动汽车用户、电动汽车充电站及电力系统三方的利益,实现对电动汽车充电站合理、灵活的控制,提出了一个基于多代理系统(MAS)控制框架下的电动汽车充电站协调控制机制,最后利用优化算法计算充电站控制命令。仿真结果表明,基于MAS控制框架下的充电站协调控制策略适用于充电站实时控制,能够在保障电网稳定性基础上,有效地维护电动汽车车主的利益。     

基于FPGA的乘法器实现结构分析与仿真

现场可编程门阵列(FPGA)的快速发展为数字信号处理(DSP)系统设计提供了一种新的解决方案，而乘法运算是DSP领域内的一种基本运算，应用极为广泛，对乘法运算基于FPGA的实现结构进行研究具有重要意义。本文分析乘法运算的特点，给出了几种适应FPGA实现的乘法器结构。并在Xilinx公司的ISE 4．1i软件环境下，采用VHDL和VIRELOG硬件描述语言进行了设计实现并对其性能进行了比较分析。     

Facile synthesis of a Bi-modified PtRu catalyst for methanol and ethanol electro-oxidation in alkaline medium

In this work a facile synthesis for a high-performance PtRuBi/C catalyst was presented through a simple mixture of commercial PtRu/C and Bi(NO₃)₃. Most of the Bimodified the PtRu particle surface via irreversible adsorption and deposition processes. X-ray photoelectron spectroscopy analysis indicated that Bi₂O₃ was the main form in the catalyst and that there exists an interaction between Bi₂O₃ and Pt. The current density of PtRuBi/C (1:1:0.2 for Pt:Ru:Bi) in the cyclic voltammograms for methanol or ethanol oxidation is over 2.6 times higher than that of PtRu/C. The anti-poisoning ability of this catalyst was also greatly improved. The Bi-containing catalyst had abundant oxygenated species and facilitated removal of poisonous intermediate species.     

热处理工艺对新型抗菌刀具用钢微观组织和性能的影响

以实验室研发的高碳高铬50Cr15MoV含Cu抗菌刀具用钢为研究材料,采用光学显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)、X射线衍射仪(XRD)和维氏硬度计研究了其在不同热处理工艺下的微观组织和力学性能变化,探索了50Cr15MoV含Cu新型刀具用钢最佳热处理工艺.结果表明,50Cr15MoV含Cu刀具用钢...     

多重（A，B）－不变子空间及多频采样控制

本文提出多重（Ａ，Ｂ）－不变子空间的概念，并给出其判据和几个基本性质．利用这些结果，得到一类多频采样干扰解耦问题可解的充要条件．     

Analog circuit intelligent fault diagnosis based on GKPCA and multi-class SVM approach

Analog circuits fault diagnosis is essential for guaranteeing the reliability and maintainability of electronic systems. In this paper, a novel analog circuit fault diagnosis approach is proposed based on greedy kernel principal component analysis (KPCA) and one-against-all support vector machine (OAASVM). In order to obtain a successful SVM-based fault classifier, eliminating noise and extracting fault features are very important. Due to the better performance of nonlinear fault features extraction and noise elimination as compared with PCA, KPCA is adopted in the proposed approach. However, when we adopt KPCA to extract fault features of analog circuit, a drawback of KPCA is that the storage required for the kernel matrix grows quadratically, and the computational cost for eigenvector of the kernel matrix grows linearly with the number of training samples. Therefore, GKPCA, which can approximate KPCA with small representation error, is introduced to enhance computational efficiency. Based on the statistical learning theory and the empirical risk minimization principle, SVM has advantages of better classification accuracy and generalization performance. The extracted fault features are then used as the inputs of OAASVM to solve fault diagnosis problem. The effectiveness of the proposed approach is verified by the experimental results.     

Optimization design of the angle detecting system used in the fast steering mirror

In this paper, in order to design a fast steering mirror (FSM) with large deflection angle and high linearity, a deflection angle detecting system (DADS) using quadrant detector (QD) is developed. And the mathematical model describing DADS is established by analyzing the principle of position detecting and error characteristics of QD. Based on this mathematical model, the variation tendencies of deflection angle and linearity of FSM are simulated. Then, by changing the parameters of the DADS, the optimization of deflection angle and linearity of FSM is demonstrated. Finally, a QD-based FSM is designed based on this method, which achieves ±2° deflection angle and 0.72% and 0.68% linearity along x and y axis, respectively. Moreover, this method will be beneficial to the design of large deflection angle and high linearity FSM.     

一种混合优化算法及其性能

结合遗传算法、粒子群优化算法和免疫算法提出了一种实数编码的混合优化算法(IG-PSOA),该方法利用非线性竞争择优的交叉操作和粒子群进化操作来提高算法的搜索效率,通过免疫选择和募集新成员操作保证种群的多样性,以避免早熟和局部收敛。从理论上分析了算法的收敛性和计算复杂度;用数值试验的方法分析了算法的鲁棒性和参数的取值范围。对7个测试函数的数值试验表明,该算法不仅提高了算法的全局搜索能力,提高了收敛的速度,而且提高了求解的质量和优化结果的可靠性,是一种有潜力的优化方法。