Kochowska Elzbieta, Németh Szilárd, Pelzl Gerhard, Buka Agnes
Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, H-1525 Budapest, P.O.B. 49, Hungary.
Phys Rev E Stat Nonlin Soft Matter Phys. 2004 Jul;70(1 Pt 1):011711. doi: 10.1103/PhysRevE.70.011711. Epub 2004 Jul 30.
Experimental electroconvection (EC) investigations on four homologs with negative dielectric anisotropy epsilona and conductivity anisotropies sigmaa of various signs (the relative sigma; a=sigmaa/sigma(perpendicular) ranges from -0.6 to +0.3 ) are reported. The homolog with positive conductivity anisotropy follows the predictions of the standard theoretical model, while the homolog with negative sigmaa shows a phenomenon, i.e., nonstandard electroconvection, not described by the Carr-Helfrich mechanism but manifesting in forms of stripes mainly parallel to the initial director, thus having a morphological similarity to the rolls of the standard EC. The remaining two homologs change the sign of their conductivity anisotropy with temperature that leads to a twofold character by crossing over from standard to nonstandard electroconvection. The patterns of both the standard and nonstandard EC have been characterized and compared.
报道了对四种具有负介电各向异性εa和不同符号电导率各向异性σa（相对σ；a = σa / σ⊥范围从-0.6到+0.3）的同系物进行的实验性电对流（EC）研究。具有正电导率各向异性的同系物符合标准理论模型的预测，而具有负σa的同系物表现出一种未被卡尔-赫尔弗里希机制描述的现象，即非标准电对流，其主要以条纹形式出现，条纹大致平行于初始指向矢，因此在形态上与标准EC的卷状结构相似。其余两种同系物的电导率各向异性随温度改变符号，这导致了从标准电对流转变为非标准电对流时呈现出双重特性。对标准和非标准EC的图案都进行了表征和比较。
