红外导引头框架式稳定平台非线性动态特性分析

通过对红外导引头框架式稳定平台进行非线性分析,得出影响框架系统稳定输出的一些设计要素。转子系统的转速变化对框架稳定性响应会出现周期、拟周期及混沌振动状态。根据非线性动力学分析结果可以看出,增加系统的阻尼可以有效地抑制平台框架的刚性混沌响应。     

微极性流体对轴承转子的影响

通过变分原理求解微极性流体润滑的Reynolds方程得到轴承转子的油膜力,以有限宽刚性Jeffcott转子为研究对象,给出了适用于微极性液体润滑剂的广义雷诺方程,用数值积分法研究了不同参数变化下有限宽轴承转子系统的非线性动力学行为。借助分岔图、Poincare映射图、时间历程图和谱分析等分析了系统的运动形态。数值分析结果表明,系统存在着拟周期运动,且在不同的参数下微极性效应越明显,即L0越小N越大系统越稳定。     

一类电路系统的分岔分析及超混沌控制研究

为了揭示电路系统丰富的非线性动力学行为,提高电路系统的稳定性,避免混沌或超混沌电路对元器件的危害,针对一类电路系统模型,应用现代数学中的微分方程理论和非线性动力学的方法,分析了系统发生分岔的条件,并通过数值分析验证了该理论结果。研究发现系统在一定参数条件下存在内衣马克-沙克分岔和倍周期分岔,随着参数的变化系统演化为混沌和超混沌。针对目前超混沌控制方法的研究较少,而且控制的周期轨道多是低周期轨道,提出一种节约能量并能将系统控制到高倍周期和概周期的方法,为研究许多现实离散系统模型提供了一种新的方法,对于研究电路系统提供了一条新的思路,因而具有一定的理论意义和实用价值。     

含无损传输线的约瑟夫森结电磁系统中的分岔与混沌

 建立了含无损传输线的约瑟夫森结电磁系统左端点处电压正向行波分量的一维Poincaré映射模型,运用非线性动力学理论分析了映射定点的稳定性。通过数值计算得到了映射随电压反射系数变化的分岔图,详细分析了系统随参数变化的动态演化过程。结果表明在一定参数条件下,该电磁系统中存在着分岔、混沌、周期吸引子共存、混沌吸引子共存以及周期与混沌吸引子共存等复杂的非线性动力学行为。     

考虑几何非线性时双稳态压电悬臂梁响应分析

针对双稳态压电振子产生大挠度振动现象,利用哈密顿原理建立了其大变形动力学方程,再用Galerkin法将其离散为模态坐标方程。对无量纲化方程进行数值分析可知:在激励一定下,存在最优阻抗使输出功率最大;在相同的激励水平下,大幅周期运动发电能力优于大幅混沌运动;通过对比发现几何非线性使系统产生更多的混沌窗口,改变梁长可使系统处在大幅周期运动中,从而提升压电发电能力。     

考虑几何非线性时双稳态压电悬臂梁响应分析

针对双稳态压电振子产生大挠度振动现象,利用哈密顿原理建立了其大变形动力学方程,再用Galerkin法将其离散为模态坐标方程。对无量纲化方程进行数值分析可知:在激励一定下,存在最优阻抗使输出功率最大;在相同的激励水平下,大幅周期运动发电能力优于大幅混沌运动;通过对比发现几何非线性使系统产生更多的混沌窗口,改变梁长可使系统处在大幅周期运动中,从而提升压电发电能力。     

卷筒纸印刷机折页机构运动学方程直接积分解法

针对运动副间隙和轴承滚子变形引起的折页机构非线性动态响应问题,提出刚性杆与弹簧组合假设,建立了折页机构间隙动力学模型.对含二阶偏微分方程组的含间隙折页机构动力学模型,采用非线性系统直接积分法进行求解.非线性系统分析的核心归结为系统状态方程的求解问题,对于一般非线性控制系统,通过引入由状态量、控制量与自变量时间t为坐标构成的"广义状态空间",在广义状态空间处将方程的右端展开为关于时间的Taylor级数,进一步直接积分获得非线性控制系统状态方程关于自变量时间的级数解.以卷筒纸印刷机折页机构这种存在耦合的非线性系统为例,利用本文提出的解法得出了输入量与输出量的解析解,并仿真验证了方法的正确性.     

多介质激光系统的动力学复杂性及混沌的控制

研究了非线性多介质激光耦合系统动力学行为的复杂性,即Hopf分岔和混沌特性.研究发现:即使注入每个介质的抽运功率和介质之间的耦合系数都一样,系统的动力学行为也会发生惊人的变化.在满足强耗散近似的单向耦合下,随着光强A的增大,系统的多稳现象越来越丰富;随着介质数N的增大,Hopf分岔点也越来越多.由于多介质激光系统遵循延时微分方程,求解十分困难,本文应用改进的分解法及其数学机械化方法,在计算机上实现自动推导,得到了多介质激光系统的高阶逼近解,然后研究了多介质系统在强耗散情形下Hopf分岔和混沌的复杂性与系统各种参数的关系.同时还研究了多介质激光系统复杂性的控制,即对Hopf分岔和混沌进行了有效的控制.为此,分析了延迟反馈方法控制混沌的原理和稳定性条件,实现了对多介质非线性激光系统中的混沌控制,已能达到稳定周期16以上任何所需的周期轨道.最后讨论了混沌控制的应用前景.(OA5)     

改进型文氏桥混沌振荡器：建模、分析 与实验

通过引入二极管—电感并联网络实现了一种改进型文氏桥混沌振荡器。借助于二极管含寄生电容的分段线性模型,有效解决了该混沌电路的动力学建模问题。基于系统模型,研究了系统的平衡点及其稳定性,利用数值仿真和硬件实验手段,揭示并验证了随系统参数变化的动力学行为。结果表明,新提出的改进型文氏桥混沌振荡器有着简单的电路结构,存在混沌和周期等非线性动力学行为。     

Chen系统的状态变量周期性反馈控制

采用非线性反馈控制,用附加了带参数的正弦项对Chen系统进行了有效的控制.随着参数k的逐渐增大,系统的动力学行为呈现出一系列的变化.数值研究结果表明:随控制参数的增大,驱动信号的强度渐大,混沌系统由混沌运动到周期轨道,最终到一相点.     

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.