聚2,3—二硫代吩噻嗪的电流变性质研究

聚２，３－二硫代吩噻嗪的电流变性质研究肖深初（湖南化工研究院长沙４１０００７）林源斌申东升王安民朱礼仁（湘潭大学化学系湘潭４１１１０５）关键词电流变流体电流变性质有机半导体中图分类号Ｏ６３１．２１电流变学（Ｅｌｅｃｔｒｏｒｈｅｏｌｏｇｙ）是研究在电场...     

Effect of Electrode Pattern on the Column Structure and Yield Stress of Electrorheological Fluids

For electrorheological (ER) suspensions, the aggregate structures of particles were observed in electric fields by the use of transparent cells with different electrode patterns. Although the suspension is dispersed to noninteracting particles without electric fields, many aggregates are formed on the electrode surface in electric fields. Since the dipole–dipole interactions cause chain structures of particles and equilibrium conformations of chains are always aligned with electric field, the aggregates indicate the presence of columns spanning the electrode gap. The particle concentration in columns which are developed between parallel-plate electrodes is about 22 vol %. In striped electrodes, the particles construct striped aggregates along the electrodes and no particles remain in the insulating region. The particle concentration in striped aggregates is about 35 vol %. The nonuniformity of electric field is responsible for the high particle concentration. The increase in particle concentration of column lead to the high yield stress of electrified suspension. Therefore, the ER performance of suspension as an overall response can be improved by the electrode design.     

Disk level S-matrix elements at eikonal Regge limit

We examine the calculation of the color-ordered disk level S-matrix element of massless scalar vertex operators for the special case that some of the Mandelstam variables for which there are no open string channel in the amplitude, are set to zero. By explicit calculation we show that the string form factors in the 2n-point functions reduce to one at the eikonal Regge limit.     

Electrorheological effect in hybrid fluids with liquid crystalline additives

Conventional electrorheological (ER) fluids consist of electrically polarizable particles dispersed in an inert insulating liquid. They are characterized by a development of a yield stress upon application of an external electric field. They resemble Bingham fluids with yield stress value depending on electric field. A viscosity increase in the presence of an electric field has been also found in homogeneous solutions of liquid crystalline polymers with no yield stress observed. In this study these two types of fluids and combined dispersions of the solid particles in the liquid crystalline matrix were investigated. A lyotropic liquid crystalline polymer—poly(n‐hexyl isocyanate) (PHIC)—dissolved in xylene was chosen as the active matrix. The dispersed solid phase was comprised of two kinds of polymers: pyrolyzed polyacrylonitryle (PAN) showing electron conductivity, and PAN doped with two salts (KSCN, NaSCN), resulting in ionic conductivity. The rheological measurements under an electric field were performed. The pristine xylene solution of PHIC was characterized first as well as the 15% m/m dispersions of PAN powders in silicone oil. Then the dispersions in the liquid crystalline matrix were investigated showing a strong ER effect whose magnitude was considerably enhanced in comparison to both ER active components measured separately. Copyright © 2006 John Wiley & Sons, Ltd.     

电流变液与电-磁流变液的衍射特性

本文把电流变液装置作为反射光栅研究其衍射特性,首次提出由电场强度改变来调节光栅常数的概念.并讨论了同时外加电场与磁场的情况下,电磁流变液的衍射特性.     

电流变液在两平行电极板间流动行为的实验研究

通过实验的方法研究了电流变液流经两间距为１．１ｍｍ的平行电极板的流动行为，实验所观测到的由于电流变液在电场作用下非均匀固化所引起的固相颗粒淤积与饱和过程、河道分岔和失稳等现象，对现有的有关电流变阀均匀流动模型提出了质疑，这为进一步深入理解电流变液的力学行为，建立新的理论模型提供了实验依据     

体积分数对基于沸石和硅油的悬浮液的电流变性能的影响

用 HAAKE RV2 0型流变仪 ,在不同外加电场强度和不同颗粒体积分数下测试了基于沸石和硅油的电流变液的剪切应力变化 .结果表明 :随着外加电场强度升高 ,电流变液的零电场粘度急剧增加 ,电流变液的剪切屈服应力增加 ;随着电流变液中沸石颗粒体积分数升高 ,电流变液的剪切屈服强度急剧上升 .这种变化可以用颗粒间作用力与颗粒间距的关系、单位面积的颗粒链数目变化以及多体作用对电流变液性能的影响来解释     

Visualizing endomembranes with confocal microscopy in protoplasts and cells of tobacco

The distribution and redistribution of the endoplasmic reticulum (ER) was studied with Confocal Laser Scanning Microscopy (CLSM) during the regeneration of tobacco protoplasts. In freshly isolated protoplasts the ER is cisternal in appearance, forming aggregates of plate-like structures clustered around the chloroplasts. During the cell's development, the ER profiles first lose the clustered appearance, then gradually tubular forms develop. Finally mixed population of some cisternal and tubular shapes and a lot of discrete spherical or cylindrical vesicles is spread through the cell's cytoplasm. The probe 3,3'-dihexyloxacarbocyanine iodide (DiOC₆(3)) proved to be a very efficient tool, allowing observations with a resolution of 0.2 μm.