抛光CVD金刚石的夹具设计及实验研究

热铁盘法抛光CVD金刚石需要在800℃以上的真空环境下进行,抛光过程中金刚石的固定,常采用陶瓷胶粘结的方法,该法在实际使过程中经常出现陶瓷胶粘结不牢而导致金刚石脱落.据此设计出一套高温真空环境下使用的金刚石夹具,在抛光厚度0.7 mm的金刚石时,将其装夹在0.4 mm深的凹槽内,留出0.3 mm左右的高度以供抛光.加载方式可以实现加热过程中无载荷,抛光过程中施加载荷.实验表明,该夹具在抛光过程中,可以实现金刚石的完全固定,并能在273 mm/s的抛光速度条件下稳定工作.在温度800℃,速度273 mm/s,载荷2.54 kg,抛光30 min的条件下,金刚石表面粗糙度可由原始的Ra9.6 μm抛光至Ra0.16 μm.     

折板跌落式竖井设计约束条件研究

结合国内深层隧道排水工程-广州市东濠涌深层排水隧道,通过物理模型试验探讨了不同折板间距情况下折板竖井消能规律,并根据竖井中水流在折板间需满足的过流能力及充分消能的约束条件,研究了折板竖井消能的最大过流流量及稳定消能边界,提出了折板竖井设计应同时满足的约束条件以及折板通气孔的推荐位置。研究表明,在折板间距与折板宽度的比值小于0.408时,约束条件只有最大过流能力;当比值大于0.408时,只需考虑充分消能的约束条件。     

网络环境下社会管理的组织行为建模与计算实验研究综述

从网络环境下社会管理、组织行为与影响力建模、社会系统的计算实验、社会系统的探索性分析与优化设计四个方面对网络环境下社会管理的组织行为建模与计算实验的研究现状进行了综述. 在此基础上提出了相应的后续研究方向:网络环境下社会管理结构框架与运行机理、网络群体行为分析与影响力建模方法、社会管理的博弈机理、基于多智能体的社会管理计算实验方法和基于计算实验的社会管理策略探索性分析与评估.     

Robust Saturated PI Joint Velocity Control for Robot Manipulators

It is well known that many industrial manipulators use an embedded linear proportional‐integral (PI) joint velocity controller to guarantee motion control through proper velocity commands. However, although this control scheme has been very successful in practice, not much attention has been paid to designing new PI velocity control structures. The problem of analyzing a saturated PI velocity joint velocity controller is addressed in this paper. By using the theory of singularly perturbed systems, the closed‐loop system is studied. The robot dynamics assumed in this paper take into account bounded time–varying disturbances which may include the friction at the joints. An experimental study in a planar two degrees‐of‐freedom direct‐drive robot is also presented, confirming the advantage of the new saturated PI joint velocity controller.     

A hybrid metaheuristic approach for the capacitated p-median problem

The capacitated p-median problem (CPMP) seeks to obtain the optimal location of p medians considering distances and capacities for the services to be given by each median. This paper presents an efficient hybrid metaheuristic algorithm by combining a proposed cutting-plane neighborhood structure and a tabu search metaheuristic for the CPMP. In the proposed neighborhood structure to move from the current solution to a neighbor solution, an open median is selected and closed. Then, a linear programming (LP) model is generated by relaxing binary constraints and adding new constraints. The generated LP solution is improved using cutting-plane inequalities. The solution of this strong LP is considered as a new neighbor solution. In order to select an open median to be closed, several strategies are proposed. The neighborhood structure is combined with a tabu search algorithm in the proposed approach. The parameters of the proposed hybrid algorithm are tuned using design of experiments approach. The proposed algorithm is tested on several sets of benchmark instances. The statistical analysis shows efficiency and effectiveness of the hybrid algorithm in comparison with the best approach found in the literature.     

基于Flash的虚拟大学物理实验研究

目前,以计算机技术为基础的虚拟大学物理实验已经成为高校物理实验教学的一个热点。将虚拟物理实验应用于教学可以弥补传统实验教学的不足,提高实验教学效果。以Flash8.0为平台,针对目前国内普通高校学生的水平,为大学物理实验虚拟实现了一个案例。实验的主体结构设计合理,界面友好,操作简单,达到了实验教学的要求。     

浅谈计算机网络虚拟实验系统的现状及发展趋势

计算机技术、网络技术和仿真技术的发展为网络虚拟实验系统的构建提供了可能。介绍了网络虚拟实验系统的国内外研究现状,分析了当前研究的不足,提出了网络虚拟实验系统发展趋势。     

基于MATLAB的信号与系统虚拟实验系统设计

信号与系统课程的概念抽象、公式繁杂,实验教学能更好培养学生操作技能和创新能力,然而传统的实物实验存在许多不足之处,本系统利用MATLAB/GUI提供的可视化界面,设计和实现包括滤波器、连续信号的分解与合成、信号的抽样与恢复、信号的调制解调等模块的实验系统,对其功能一一进行演示,对原理结论进行验证。本系统操作简单,用户能够根据要求自行输入参数设计实验系统。系统反映直观,对比信号通过该对应系统的输出响应可促进学习者对抽象理论的快速理解,有利于创新意识和创新能力的培养。     

Optimal experimental design and some related control problems

This paper traces the strong relations between experimental design and control, such as the use of optimal inputs to obtain precise parameter estimation in dynamical systems and the introduction of suitably designed perturbations in adaptive control. The mathematical background of optimal experimental design is briefly presented, and the role of experimental design in the asymptotic properties of estimators is emphasized. Although most of the paper concerns parametric models, some results are also presented for statistical learning and prediction with nonparametric models.