The implementation methodology of the real effects in a NOI nanostructure,aided by simulation and modelling

The SOI transistors permanently offer new candidates as nanodevices. The nothing on insulator NOI transistor was recently derived from the nano SOI–MOSFET family. Their output characteristics were theoretical modelled with an exponential law, validated by simulations. The transfer characteristics presented sometimes increasing and others times decreasing monotony. This phenomenon was put directly into a relationship with the gate tunnelling breakdown. This paper has three final targets: the breakdown limitation through the back-gate terminal, the real effects including in the NOI transistor architecture – like interface charges or metal-semiconductor work function and quantum effects corrections in simulations, in order to produce a better correlation between simulations and a real behaviour. These simulations represent a milestone in the NOI nanotransistor manufacturing, establishing some parameters that link the device to the real work regime.     

开关磁阻电机驱动系统建模与控制研究

分析了开关磁阻电机(SRM)非线性动态模型和在电动和制动状态下的控制模式,并在Matlab/Simulink环境下对SRM驱动系统进行建模。仿真结果真实反映了SRM的实际工作情况,模型具有很好的通用性,为进一步研究对SRM的控制提供了基础。     

粒子群优化算法在电力系统中的应用综述

粒子群优化(PSO)算法是一种新兴的群体智能优化技术,其思想来源于人工生命和演化计算理论,PSO通过粒子追随自己找到的最优解和整个群的最优解来完成优化。该算法简单易实现,可调参数少,已得到广泛研究和应用。在大量参阅国内外相关文献的基础上,简要介绍了PSO算法的工作原理,较为全面地详述了粒子群优化方法在电力系统中的应用,如电网规划、检修计划、短期发电计划、机组组合、负荷频率控制、最优潮流、无功优化、谐波分析与电容器配置、参数辨识、状态估计、优化设计等方面,并对今后可能的应用指出了研究方向。     

预变量与时效温度对Fe—Mn—Si合金记忆效应的影响

研究了预变形量和时效温度对Fe-28Mn-5．7Si-5Cr-0．82Ni-0．045Nb合金形状记忆效应的影响。结果表明，合金形状回复率随预变量的增大而减小，在2％左右合金回复率可以达到80％。合金经1023K时效处理时形状记忆效应最好，比固溶态提高了90％，这主要是时效处理有效提高了奥氏体基体的强度，而奥氏体基体的强度的提高可以抑制塑性变形的产生。     

基于J2EE和Matlab的发电厂继电保护综合管理系统

基于J2EE平台和Web服务的综合集成方案,既能充分利用J2EE平台的成功优势,又能以互操作性更好的方式展现整合企业信息系统功能。面向服务层,将计算平台、图形化平台集成于统一的信息化管理平台之中。介绍了一种面向服务层的基于J2EE和Matlab的发电厂继电保护综合管理系统。分析其总体结构、主要功能模块和技术特点。系统采用分布式J2EE架构,与Matlab有机结合,实现了发电厂继电保护信息管理、故障分析、保护整定等功能。该系统具有较好的实用性和通用性。     

毫米波辐射计缩比测试研究

缩比测试是在较低高度下对满足缩比条件的小目标进行测试,以等效在真实高度下对大目标进行测试的情况。文中针对毫米波辐射计的探测研究,讨论了其缩比测试的原理及条件,并在两种高度下进行了实际的毫米波辐射计缩比测试及相应真实高度下的塔载测试,结果对比表明了缩比测试的可信性。该方法简单易行,可节省大量经费。     

虚拟仪器技术在电路教学中的应用

针对"电路理论"教学过程中学生在理解上存在困难的部分章节,利用虚拟仪器技术灵活多变、形象生动的特点,我们制作了部分教学演示软件.利用虚拟波形发生器和虚拟示波器等技术可使电路中枯燥难懂的概念与理论公式以虚拟波形的方式动态、实时交互地展现出来,增强了学生的感性认识,有效地提高了课堂的教学效果.     

基于神经网络逆系统的无轴承异步电机非线性内模控制

针对无轴承异步电机非线性、多变量、强耦合的特点,提出一种基于神经网络 α阶逆系统方法的非线性内模控制策略.将用动态神经网络逼近的无轴承异步电机 α阶逆模型与原系统复合,将非线性的无轴承异步电机原系统解耦成转子径向位移、转 速和转子磁链四个独立的伪线性子系统.为了保证 系统的鲁棒性,对伪线性系统引入内模控制,仿真和实验研究验证了所提控制方法的有效性.     

Fracture of cutting tools due to the formation of untempered martensite

Three case studies are presented in which untempered martensite produced during forming or use caused premature failure or failures in unexpected regions. The sources of formation of untempered martensite observed were: laser cutting of circular saws, friction originated from poor fixation of blades, and uncontrolled thermal cycling in the vicinity of a weld. Due to its very high hardness, untempered martensite favors the appearance of microcracks that develop into premature catastrophic failures.     

Parametric study of texturing in convergent bearings

The effect of textured surfaces in hydrodynamic bearings is assessed using a mass-conserving numerical analysis that allows for arbitrary geometry and multiple regions of cavitation. The texture investigated consists of regularly spaced rectangular pockets through an (infinitely) long linearly convergent or parallel bearing. This arrangement leads to nine independent non-dimensional parameters including operating conditions. The effectiveness of texture at improving load support and reducing friction over a corresponding plain bearing is described in relation to these parameters and the important interaction between parameters is highlighted. The beneficial or detrimental effect of texture is explained in terms of the fundamental mechanisms of hydrodynamic pressure generation including inlet suction.