基于ACIS的实体模型的面片化技术及其应用

VTK(Visualization Toolkit)是可视化领域最负盛名的可视化软件开发包,但他目前不能直接处理实体模型,这妨碍了基于VTK的软件和CAD软件的对接,因为大部分CAD软件都使用实体模型。首先讨论了基于ACIS实现实体模型面片化的技术,并在此基础上设计了vtkSTEPImporter类,使得基于VTK的软件可以直接读取实体模型,从而使得基于VTK的软件和CAD软件可以实现无缝连接。所介绍的方法在科学计算可视化集成平台软件SVIP中得到应用,效果良好。     

模糊PID算法在PLC中的一种实现方法

目前PLC被广泛的应用于自动化领域。常规的PID算法依赖于理想化的控制模型,对非线性系统的控制效果较差。实践证明常规PID很难满足高精度控制系统的要求。模糊算法具有较强鲁棒性,不需要精确的数学模型,对非线性系统控制效果较好。因此,研究模糊PID算法在PLC中的应用具有一定的现实意义。文章针对模糊PID算法计算量较大的特点,提出使用MATLAB的模糊控制工具箱离线求出了模糊控制查询表,采用STEP7软件进行了查表程序设计,实现模糊PID算法在PLC中的应用。     

Step7中PID控制器(FB41)在重介密度控制中的应用

可编程序控制器(PLC)在控制领域具有强大的功能,为了充分发挥PLC的功能,相应的编程软件也在不断地改进,本文在阐述西门子编程软件STEP7功能模块在密度控制中自动加水,调节密度的应用时间,着重量介绍了PID参数的作用及常用方法。     

基于SPDA的电脉冲除冰供电负载控制算法研究

为了减小采用基于SPDA的飞机电脉冲除冰供电对变频交流配电网电源品质的影响,针对电脉冲除冰负载控制问题,提出了BP神经网络PID控制算法。 该算法充分利用神经网络的自学习能力和逼近函数的能力及PID控制的鲁棒性,有效地提升了电脉冲除冰负载控制能力,使用仿真软件分析初步验证了该控制方法的有效性,并基于实验平台模拟飞机变频发电机(VFG)对发动机短舱进行除冰供电。实验结果显示,提出的基于BP神经网络PID控制方法是有效的。     

科学计算软件Octave在电路分析中的应用

通过具体实例,文章重点介绍了可替代Matlab的免费开源科学计算软件Octave在电路分析中的应用,展示了该软件强大的符号计算、数值计算以及绘图功能,也证明了其可被作为低成本电路分析的有效辅助工具。     

直流-交流变换电路建模与仿真

直流-交流(DC-AC)变换电路,也被称为逆变器,可以把直流电能转换为交流电能。逆变器已广泛应用于交通、工业、航空航天、能源等领域,如频率控制装置,电解电镀电源,感应加热电源,不间断电源,焊接电源等。而且现在我国新兴并正在大力发展的光伏发电技术就需要运用大量逆变电路才能将太阳能转化而来的直流电能转换成日常生活可用的交流电能。本毕业论文主要对电路结构进行逆变器的分析说明。而使用MATLAB可以很好的完成对设计电路的建模与仿真MATLAB是一款基于矩阵的交互式程序计算语言的科学计算软件。本文主要基于MATLAB/SIMULINK仿真软件,对单相桥式全控整流及有源逆变电路、三相半波整流及有源逆变电路、三相桥式整流及有源逆变电路进行了建模与仿真,并且对所得出的仿真结果进行研究和计算。     

基于网格的科学计算的公平服务方法研究

在科学与工程计算领域，各种科学计算库及其工具软件扮演着十分重要的角色。在科学计算网格中．通过引入软件代理可以更好地利用这些计算库和工具软件库。本文通过对网络化科学计算工具NetSolve的分析．通过引入服务队列、访问率、时差和连续性等因子，改进了其中的用户访问策略和资源调度方法，使其具有资源访问的公正性和负载均衡性。     

云计算环境下分布存储的关键技术

云计算(cloud computing)作为一种新型的计算模式,在商业计算领域和科学计算领域中均发挥着重要的作用。云计算环境下的分布存储研究数据主要集中在数据中心的组织方面和管理方面,研究数据作为云计算环境的核心基础设施,通常情况下由100万级以上的节点组成,存储上的数据规模达到FB/EB级,最终使得数据失效成为一种比较常见的状态,在很大程度上限制了云计算的推广和应用等,增加了云计算的成本。基于此,降低成本以及提高扩展性等成为了云计算环境下分布存储研究的关键技术。笔者将根据相关工作经验。综合分析云计算环境下分布存储数据的关键技术,以期能够给相关工作者提供可参考的意见。     

PID算法的FPGA实现

PID控制器作为一种传统的控制方法在现代工业现场应用仍然非常广泛,实际工程中使用的PID控制系统多为基于单片机技术的软件实现,其实时性与抗干扰性能并不理想。本文采用现场可编程逻辑门阵列(FPGA)来设计一款硬件PID控制器,很好地克服了软件实现方案的上述缺点。实际运行结果表明,采用该方法可明显改善效果,在简化设计的同时可以提高系统的实时性和抗干扰性。     

干涉式闭环光纤陀螺仪的PSO-PID控制优化方法

控制系统的设计会对响应速度快且应用范围较广的数字干涉式闭环光纤陀螺(ICFOG)动态性能产生影响。通过分析ICFOG的工作原理,推导出闭环离散控制系统,并利用粒子群优化算法(Particle Swarm Optimization,PSO)对传统的PID控制器参数进行优化。基于这个优化过程,设计一种新型的PSO-PID复合控制器,以取代传统的PID控制器。通过与其他BP神经网络、模糊控制等方法进行对比凸显该控制方法的优越。通过数字仿真分析显示,跟踪速度相较于BP-PID控制方法提高了1.91倍,相对于PID控制方法提高了3.5倍,相对于F-PID控制方法提高了1.75倍。同时,控制精度相对于BP-PID控制方法提高了46.03%,相对于PID控制方法提高了66.30%,相对于F-PID控制方法提高了45.27%。结果显示,采用PSO-PID控制器能够快速达到控制目标且具有较小的超调量。     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.