工业机器人手臂结构的有限元分析与研究

本文采用有限元的方法，对典型机器人手臂进行力学分析。所选取的平面壳体等参单元是将平面应力问题与板弯曲相叠加，并选用拟合性好的等参单元进行计算，在力学分析的基础上，确定了平面壳体单元的刚度矩阵，并根据载荷情况求出节点位移。实践证明，这种有限元分析方法有较高的实用性，为工业机器人手臂结构的优化提供了理论基础。     

A numerical study of the spatial stability of three-dimensional developing plane mixing layer

This paper is concerned with the hydrodynamic stability of the free shear llayer. The concern of this study lies in obtaining solutions for the viscous spatially three-dimensional stability corresponding to the classical self-similar velocity profile of the free shear layer. In this study several techniques are applied to resolve the serious numerical complication introduced by the finite domain and parasitic contamination of the solution. As the spanwise wave number decreases, the neutral stability occurs at higher frequencies, β. The maximum amplification rate (α _imax ) inereases when spanwise wave number decreases. The decrease of — α _imax with γ at a fixed Reynolds number is quite linear with the exception of low spanwise wave number (γ≤0.2).     

Modeling and hybrid simulation of slow discharge process of adsorbed methane tanks

The slow discharge process of a methane tank filled with porous carbonaceous adsorptive material is modelled and solved by the Integral Transform Method, yielding a hybrid numerical-analytical solution of the related energy equation. A transient one-dimensional nonlinear formulation is adopted, which includes the compressed and adsorbed gas thermal capacitances, the reservoir wall thermal capacitance effect and the gas compressibility influence. The overall mass balance is employed to determine the pressure field evolution, here assumed as spatially uniform. A thorough covalidation analysis is performed, with both numerical and experimental data available in the literature, and the relative importance of some terms in the energy equation formulation is inspected. Finally, different possibilities for the reduction of the adverse effect of the heat of adsorption on storage capacity are proposed and investigated.     

轴向推力滚子激振式振动台设计研究及仿真分析

提出一种新型机械振动台,分析其机构组成及工作原理,建立激振元件曲面数学方程。通过所建机构动力学方程,导出弹簧预紧量与临界频率间函数关系;进行振动台三维模型运动仿真试验,分析输出波形的频谱及功率谱,计算其加速度波形失真度;验证弹簧预紧量与临界频率间关系。试验结果表明该振动台的输出波形精度及上限频率高于传统机械振动台,且该激振方法可行、有效。     

Stability Analysis of a Simple-Structured Fuzzy Logic Controller

The stability analysis for the fuzzy logic controller (FLC) has widely been reported. Furthermore some researches have been introduced to simplify the design process of FLCs. One of them is to decrease the number of parameters representing the antecedent part of the fuzzy control rule. So we briefly explain a simple-structured fuzzy logic controller (SFLC) which uses only a single variable at the antecedent part of a fuzzy control rule. We analyze that it is absolutely stable based on the sector bounded condition. We expand a nonlinear controlled plant into a Taylor series about a nominal operating point. The fuzzy control system is transformed into a Lure system with nonlinearities. We also show the feasibility of the proposed stability analysis through a numerical example of a mass-damper-spring system.     

Fast release process of metal structure using chemical dry etching of sacrificial Si layer

An ultra-fast removal process of a silicon sacrificial layer for the selective release of a metal structure on a Si substrate was studied, which uses a chemical dry etching method. The chemical dry etching of a Si layer was performed in an NF₃ remote plasma with the direct injection of additive nitric oxide (NO) gas. When the NO gas was injected into the chamber into which F radicals were supplied from a remote plasma source using NF₃ input gas, the silicon layer was removed selectively and the metal structure could be released easily. It was found that the etch rate on the sidewall (up to ≅ 18.7 μm/min for an opening width of 100 μm) and the bottom (up to ≅ 24.5 μm/min for an opening width of 100 μm) depends on the NO/(NO + Ar) gas flow ratio, time duration, and opening width. The developed dry etching process could be used to release a Ni structure with near infinite selectivity in a very short time. The process is well suited for fabricating various devices which require a suspended structure, such as in radio-frequency microelectromechanical system switches, tunable capacitors, high-Q suspended inductors and suspended-gate metal-oxide semiconductor field-effect transistors.     

(Sn-9Zn)-xBi钎料组织性能研究

运用莱卡显微镜、X射线衍射仪及电化学测试系统等仪器设备,对(Sn-9Zn)-xBi(x=0,1,3和5)钎料组织性能进行研究。结果表明:当x小于5时,Bi可明显影响(Sn-9Zn)-xBi钎料中富Zn相尺寸及分布,钎料的熔化温度随Bi含量的增加而降低至188℃;钎料的润湿性随Bi含量增加而得到改善,其中以x在1～3为最明显;与Sn-9Zn钎料相比,当x为3时,钎料显微硬度提高了31%,达到最大值22.3HV;钎料腐蚀电位随x变化不大,但x为5时腐蚀电流密度却减小至未添加Bi的Sn-9Zn钎料的25%。     

面向纺织服装企业的知识表示与获取技术研究

探讨了纺织服装企业知识管理过程中的知识表示与获取技术．分析了元数据、RDF／XML、知识地图技术，将其与纺织服装企业知识的类型及特点相结合，研究并提出采用RDF／XML技术的纺织服装企业显性知识表示与获取方法、采用XML技术的纺织服装设计实例知识表示与获取方法，以及采用知识地图技术的纺织服装领域专家知识表示与获取方法．     

三例人体颈动脉分叉管血液动力学的数值对比分析

颈动脉粥样硬化的发生常常呈现出强烈的几何选择性特征,表明其几何形状对局部血液动力学特征影响很大.本研究采用Mimics软件对三例真实人体颈动脉分叉管的CT影像数据进行了图像处理,重建了三维几何模型.对三种不同出口流量分配比条件下的脉动血液流场进行了全三维数值模拟,重点分析了流量分配比和分叉管几何特征对局部血液动力学的影响.计算结果表明:(1) 内外颈动脉血液流量分配比的变化对颈动脉分叉管内的血液动力学特征影响很大,但具体程度因颈动脉形状差异而不同;(2) 颈动脉分叉角或颈动脉窦较大时,颈动脉分叉处流动比较紊乱,低速区和低壁面剪应力区面积较大,使得粥样硬化风险较高.