空间各向异性色散两体势向列相液晶形变研究

基于空间各向异性色散力势能,用简单的立方格子模型研究具有n层液晶分子所组成的向列相液晶形变。理论外理中假定具有理想向列序,这意味着分子长轴取向方向与液晶指向矢是一致的．而总自由能等于相互作用能。文中以解析形式研究了三种基本的Fredericksz转变,给出了三个弹性常数,在近似下它们是相同的,且与连续体理论比较可以得到k13。     

基于向列相液晶形变研究空间各向异性两体势

基于分子两体势研究向列相液晶的形变。该两体势是空间各向异性的并且依赖于液晶的弹性常数。理论处理中假定具有理想向列序,这意味着分子长轴取向方向与液晶指向矢是重合的,而总自由能等于总相互作用能。通过解析形式研究3种基本的弗雷德里克兹转变,得到了势参数与弹性常数的又一关系。通过MonteCarlo模拟方法研究了新两体作用势所描写向列相的热力学性质。     

表面极化的二粒子集团理论

应用二粒子集团理论研究了基板对极性分子构成向列相液晶的作用。假定分子质心固定在简单立方晶格的格点上,分子间存在色散作用和偶极相互作用,与基板相接触的一层分子受到表面作用,在二粒集团近似下导出了分子取向分布函数所满足的方程,并用迭代方法求解,得到如下结论：在向列相液晶与固体基板相接触的界面上,会出现极化层,当基板的表面作用足够强时,界面极性序几乎独立于温度,不受体液晶相变影响。     

分子双轴性与液晶向列相的最高过热温度

向列相(N)-各向同性相(I)相变为弱一级相变，其相变潜热大约比溶化的相变潜热小2个数量级。在这种弱一级相变附近焓随温度的变化表明：各向同性相最低过冷温度T^*、N-I相变温度TC和向列相最高过热温度T^**彼此十分接近。本文通过分子统计理论研究这一现象。形成单轴向列相的液晶分子并不具有D∞对称性。在分子场近似下和二粒子集团近似下，随分子双轴性参数增大，T^*／T^**增大并趋近于1。     

磁场对双轴分子液晶的影响

在分子场近似下,研究分子双轴性对向列相液晶在各向同性相最低过冷温度的影响,以及对临界磁场的影响。当外加磁场大于临界磁场时,不发生向列相－各向同性相相变。理论结果表明,通过考虑分子双轴性,最低过冷温度Ｔ＾＊与相变温度Ｔｃ的比值向实验值靠近。随着分子双轴性的增加,临界磁场很快下降。     

热致聚芳酯液晶的缺陷结构及电镜研究方法

热致聚芳酯液晶的有序性属向列相。在向列相中分子的长轴方向倾向平行于某个公共轴,这个公共轴用指向矢n表示,取向形变不大的条件下,向列相体系可以用连续体理论来描述,指向矢场n(r)是连续函数。实际的液晶中存在着指向矢函数不连续的奇异点或奇异线,Frank称之为向错(Disclination),是液晶中的缺陷结构。在向列相液晶中能稳定存在的向错只有向错点和向错线,向错面完全不稳定。可以用强度来表征向错,一般只有强度S=±1/2和S=±1的向错是稳定的,S=+1包括了三种情况,因此能稳定存在的向错主要有六种基本形式。在向错点或向错线周围有限的范围内,分子将连续地调整其取向,形成一些具有特殊形式的指向矢场。     

场致胆甾相-向列相转变:基于分子场理论的研究

垂直于液晶胆甾相加磁场可以引起胆甾相-向列相转变，基于分子场理论解释了这一现象。在液晶胆甾相，单体取向分布函数按照指向矢的改变定域化。通过对磁场中单分子取向势求平均得到宏观磁场能量；对分子两体作用势作展开，自由能转换为在连续体理论中所具有的形式．得到了发生转变临界磁场的公式。近似计算了温度对临界磁场的影响。     

电场对铁电液晶分子排列的影响

本文通过在铁电液晶相变过程中施加交变电场的方法，研究了电场对铁电液晶分子排列的作用。实验表明在液晶相变点附近施加低频交变电场，能够使铁电液晶分子形成均匀排列，从而提高了铁电液晶器件的记忆效应与对比度，最后我们给出了合理的理论解释。     

向列相液晶四波混频的若干问题

对向列相液晶四波混频进行了理论分析,总结了提高向列相液晶四波混频衍射效率的方法,评述了其相位共轭的研究现状和前景.     

无摩擦基板上液晶薄层的分子场理论

采用分子场近似，通过Ｌｅｂｗｏｈｌ－Ｌａｓｈｅｒ模型研究无摩擦基板上的液晶薄层，给出了出现向列相对液晶薄层中的子分子取向状态的向列相－各向同性相转变，讨论了基板诱导的取向序（包括双轴序）以及介面区中的双轴一单轴相变。     

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.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

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.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

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.     

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.