Optimisation of alignment materials for minimising residual retardation in in-plane switching liquid crystal display

The light leakage in a black state of in-plane switching (IPS) liquid crystal display (LCD) associated with rubbing process has been investigated. The mechanical rubbing process with a cloth caused orientation disorders in the liquid crystal directors and these partial orientation disorders result in residual retardations of the IPS LCD, causing the light leakages at the black state. In this study, we theoretically estimated how the light leakage is associated with the rubbing uniformity using 2 × 2 Jones matrix equation and also experimentally confirmed how it is associated with structural properties of the alignment layer. The light leakage was clearly reduced in the alignment layer with reduced crystallinity and flexibility.     

Towards a world‐sheet description of doubled geometry in string theory

Starting from a sigma‐model for a doubled target‐space geometry, we show that the number of target‐space dimensions can be reduced by half through a gauging procedure. We apply this formalism to a class of backgrounds relevant for double field theory, and illustrate how choosing different gaugings leads to string‐theory configurations T‐dual to each other. We furthermore discuss that given a conformal doubled theory, the reduced theories are conformal as well. As an example we consider the three‐dimensional WZW model and show that the only possible reduced backgrounds are the cigar and trumpet CFTs in two dimensions, which are indeed T‐dual to each other.     

在轴向气流作用下液体轴对称抛撒二次破碎的实验研究

液体轴对称抛撒的实验研究是以云雾爆轰武器的研制为背景的。为了研究轴向气流作用下液体轴对称抛撒二次破碎所形成的雾化场特性,本文利用两台激波管并对之加以改造,成功地在实验室实现了轴向气流作用下液体的轴对称抛撒。为了研究其雾化场的远场特性,本文利用激光粒子测量仪获得了在不同实验工况和不同位置下的雾化场SMD分布曲线。实验数据表明,由于轴向气流速度的增加,液体破碎的Weber数得到了提高,导致二次破碎初期雾化场的SMD随之减小;随着抛撒驱动压力的提高,二次破碎初期雾化场的SMD也随之减小;在同一工况下,雾化场SMD随着测量位置与喷口距离的增加而变大。     

ASYMPTOTIC DYNAMIC SOLUTION TO THE MODE PROPAGATING CRACK-TIP FIELD IN ELASTIC- VISCOPLASTIC MATERIAL

A new elastic-viscoplastic mode was proposed to analyze the stress and strain fields surrounding the tip of a propagating mode Ⅰ cracks. A proper displacement pattern was suggested and asymptotic equations were derived, and numerical solutions were illustrated. The analysis and calculation show that the crack-tip field is of logarithmic singularity for smaller viscosity, however no solution exists for large viscosity. By a careful analysis and comparison, it is found that the present results retain all merits of those given by Gao Yu-chen, while removing existing problems.     

大埋深粘土三轴高压卸载变形与强度特征

以取自山东巨野矿区埋深近 4 30～ 6 0 0m的深部粘土样为例 ,分析测试了土的常规物理力学性质参数。考虑该埋深土的天然应力水平及其在煤矿建井开挖中的卸载应力变化 ,在三轴伺服仪上 ,进行三向等压分别达 11MPa、12MPa、14MPa下的卸除围压、保持轴压的三轴高压卸载试验 ,分析了深部粘土三轴高压卸载变形和强度特点 ,得到了相关力学参数。成果丰富了土的高压卸载力学性研究 ,并为巨野矿区煤矿立井建设提供了工程地质基础参数     

用LDV系统测量转盘萃取塔内流场

本文应用激光多普勒测速仪对二种转盘萃取塔模型进行切向速度、轴向速度和湍流度测量。实验结果表明，在ＲＤＣ是切向速度比较大，因而有较大的搅拌效果，它的内部流场比较均匀稳定，有利于传质，所以ＲＤＣ是广泛应用于化学工业中的一种液－液萃取设备。     

Higher order asymptotic solution of mode I crack growth in elastic-perfectly plastic media

A higher order asymptotic solution of near-tip field is studied for plane-atrain Mode-I quasi-static steady crack growth in the incompressible (v=1/2) elastic perfectly-plastic media. The results show that the near-tip stress and strain are fully continuous, and the strain possesses In (A/r) singularity at the crack tip. The expressions of the stress, strain and velocity in each region are also given. The project supported by National Natural Science Foundation of China     

Waves in a Bed under Periodic Tangential Loading

The far-zone structure of the wave field in an elastic bed on a rigid foundation is considered. The wave field is generated by a tangential periodic force applied to the bed surface. The amplitude- frequency characteristics of surface vibrations for propagating modes are found. The partition of energy between different modes is considered.__________Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 46, No. 4, pp. 109–115, July– August, 2005.     

幂硬化可压缩材料Ⅰ型动态裂纹尖端奇异场

研究了平面应变条件下幂硬化可压缩材料中定常扩展的Ⅰ型动态裂纹尖端应力应变奇异场．采用Ｊ２流动理论和场量直角坐标分量，得到了应力应变奇异性不同时的裂纹尖端渐近场，其中场量的角变化规律和理想弹塑性材料的完全相同     

Nonlinear Responses of a Magnetoelastic Beam in a Step-Pulsed Magnetic Field

A theoretical study is carried out on the dynamics of a magnetoelastic beam being in a step-pulsed magnetic field. For this aim, the magnetic potential and elastic energies are determined for the beam and partial differential equations are established according to Hamilton's principle. It is proven that the magnetoelastic beam can give a variety of complex behavior in the case of step-pulsed field excitations. An intermediate regime of two-well chaos is observed. Theoretical findings were found to be in a good agreement with the experimental results for the specific system parameters. On leave from Institute of Physics, University of Bayreuth, 65440 Bayreuth, Germany An erratum to this article is available at .