有限元法求解液晶层中的指向矢分布

建立了基于有限元法的液晶层中指向矢分布的计算方法,可以方便地考虑非对称取向和表面锚定能及其形式对指向矢分布的影响,作为应用实例,给出了非对称弱锚定情形下的液晶层下指向矢分布的计算结果。     

表面弹性能K24项对液晶盒指向矢分布的影响

采用混合锚定非对称楔形液晶盒,导出了系统的吉布斯自由能.根据平衡态自由能最小的原理,利用变分的方法,得到了表面弹性能K24项存在时,指向矢分布满足的微分方程.通过求解方程,计算讨论了K24项对液晶指向矢分布的影响.结果表明K24项对楔形液晶盒指向矢分布的影响是不可忽视的.     

平行排列液晶盒在不对称弱锚定边界条件下的Freedericksz转变

应用液晶弹性形变的连续体理论，分析了平行取向的液晶层在不对称弱锚定边界条件下的Ｆｒｅｅｄｅｒｉｃｋｓｚ转变，给出了确定指向矢分布的方程，以及阈值电压与两侧基板表面锚定强度的关系，对称弱锚定和对称强锚定情形的阈值电压可以作为特例给出。在不对称弱锚定边界条件下，指向矢分布不再关于液晶层中心对称，在液晶层中指向矢极大倾角的位置随锚定强度和外加电压所改变。     

平行排列液晶盒的挠曲电效应及一级Fréedericksz转变

基于液晶弹性理论研究了平行排列液晶盒中的挠曲电效应,通过变分理论得到了液晶指向矢满足的微分方程及边界条件。应用差分迭代方法进行了数值求解,得到了液晶指向矢随不同的参数变化的曲线。增大液晶盒厚度、上下基板锚定能系数以及增大预倾角这3种方法,在考虑挠曲电效应对液晶指向矢分布的影响时是等效的。研究了介电效应和挠曲电效应同时作用下的一级Fr啨edericksz转变问题。当|Δ<ε|较大、A较小时,将会发生一级Fr啨edericksz转变。     

平行排列液晶盒的挠曲电效应及一级Fr(e)edericksz转变

基于液晶弹性理论研究了平行排列液晶盒中的挠曲电效应,通过变分理论得到了液晶指向矢满足的微分方程及边界条件.应用差分迭代方法进行了数值求解,得到了液晶指向矢随不同的参数变化的曲线.增大液晶盒厚度、上下基板锚定能系数以及增大预倾角这3种方法,在考虑挠曲电效应对液晶指向矢分布的影响时是等效的.研究了介电效应和挠曲电效应同时作用下的一级Fréedericksz转变问题.当|Δ＜ε| 较大、A较小时,将会发生一级Fréedericksz转变.     

平行排列液晶盒的挠曲电效应及一级Fréedericksz转变

基于液晶弹性理论研究了平行排列液晶盒中的挠曲电效应,通过变分理论得到了液晶指向矢满足的微分方程及边界条件.应用差分迭代方法进行了数值求解,得到了液晶指向矢随不同的参数变化的曲线.增大液晶盒厚度、上下基板锚定能系数以及增大预倾角这3种方法,在考虑挠曲电效应对液晶指向矢分布的影响时是等效的.研究了介电效应和挠曲电效应同时作用下的一级Fréedericksz转变问题.当|Δ＜ε| 较大、A较小时,将会发生一级Fréedericksz转变.     

强激光诱导向列相液晶指向矢转动的数值研究

激光诱导液晶指向矢转动的物理过程由欧拉-拉格朗日方程描述,激光在液晶中的传输则由麦克斯韦方程描述,在几何光学近似条件下可以利用几何光学光线传输方程来描述。通过对这对耦合的微分方程组进行数值求解,研究了激光诱导液晶指向矢转动的物理机制,讨论了激光诱导液晶指向矢转动的阈值问题,比较了不同液晶盒几何参数与不同入射激光初始偏振状态对液晶指向矢转动的影响。此外,还研究了强激光在液晶中传输时指向矢转动对激光偏振态的影响。     

同心柱筒中混合排列向列相液晶中的挠曲电效应

本文研究径向电场作用下同心柱筒中混合排列向列相液晶的指向矢分布,重点研究挠曲电效应对指向矢分布的影响。向列相液晶处于同心圆柱构成的薄层间,内表面径向锚定、外表面轴向锚定以及内表面轴向锚定、外表面径向锚定构成两种同心柱筒混合排列模型。基于向列相液晶Frank弹性理论,通过差分迭代方法,分别在强锚定及弱锚定边界条件下,研究了两种模型中挠曲电效应对指向矢分布的影响。研究结果表明:挠曲电效应在薄层内边界、外边界以及薄层内部对指向矢分布有着不同的影响;同心柱筒中指向矢分布由柱对称性、边界锚定作用、介电耦合作用、挠曲电效应的综合作用所决定。     

空间各向异性势扭曲向列液晶盒的Fredericksz转变

基于格点模型空间各向异性两体势研究扭曲向列(TN)液晶盒的Fredericksz转变。该作用势不仅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。分别对指向矢的倾角和方位角进行傅里叶展开,通过二阶导矩阵方法确定TN盒的阈值磁场。该磁场依赖于总扭曲角和液晶的弹性常数,并与连续体理论结果进行了比较。通过平衡态下系统自由能取最小,得到指向矢满足的平衡态方程。基于平衡态方程,对TN液晶盒中指向矢在磁场作用下的分布进行了数值计算。数值结果验证了液晶指向矢所满足的平衡态方程的正确性。进一步证实了文献中最近提出的两种从弹性能到两体作用势的映射方案之一(即模型Ⅰ)可以给出与连续体理论相一致的结果。     

不同初始分布向列相液晶电容特性的相场法研究

液晶盒内的液晶分子在不同的外加电场作用下重新排布,其极化指向发生改变,从而影响液晶盒整体的电学特性。本文考虑液晶材料的挠曲电效应,分析液晶盒的整体自由能表达式,包含弹性形变自由能密度、介电自由能密度和挠曲电自由能密度。基于液晶弹性理论和相场方法,构建描述液晶核指向矢分布及演化的相场方程,并运用离散方法推导出液晶盒约化电容的表达式。讨论边界强锚定的混合液晶盒(HAN)和平行液晶盒(PAN)表面电荷密度对液晶核指向矢偏转角的影响。进一步分析了挠曲电系数、表面电荷密度以及液晶盒厚度对两种不同初始指向分布液晶盒电容性能的影响。数值分析结果表明,表面电荷密度越大、挠曲电系数越小,液晶核指向矢偏角越大。在混合液晶盒中,约化电容随着表面电荷或液晶厚度的增加而增加,最终趋于饱和;而在平行液晶盒中,当表面电荷密度或液晶盒厚度达到某个临界值时,液晶核的指向矢才发生改变,液晶的约化电容才有明显的变化。随着表面电荷密度增加,液晶核指向矢发生偏转的临界厚度减小。     

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.     

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.     

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.     

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.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks     

Call for Papers—Feature Topic,Vol.12,No.7,2015

正Information Centric Networking Information-Centric Networking(ICN) is an emerging direction in Future Internet architecture research,gaining significant tractions among academia and industry.Aiming to replace the conventional host-to-host communication model by a data-centric model,ICN treats data content as the first     

JOURNAL OF ELECTRONICS(CHINA)

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NOTICE OF CHANGING JOURNAL OF ELECTRONICS （CHINA） TO MICROSYSTEMS ＆ NANOENGINEERING

正Journal of Electronics(China)(JE)was founded in 1984,sponsored by the Institute of Electronics,Chinese Academy of Sciences.JE is one of the first English academic journals in China in the field of Electronics and Information technology.The journal was published quarterly since it was launched in 1984 to 2003,then it is published bimonthly till now.During