Zhou Xuan, Zhang Zhidong, Zhang Qian, Ye Wenjiang
Department of Physics, Hebei University of Technology, Tianjin 300401, China.
Materials (Basel). 2015 Nov 30;8(12):8072-8086. doi: 10.3390/ma8125446.
The dynamics of a disclination loop (s = ±1/2) in nematic liquid crystals constrained between two coaxial cylinders were investigated based on two-dimensional Landau-de Gennes tensorial formalism by using a finite-difference iterative method. The effect of thickness ( = ₂ - ₁, where ₁ and ₂ represent the internal and external radii of the cylindrical cavity, respectively) on the director distribution of the defect was simulated using different ₁ values. The results show that the order reconstruction occurs at a critical value of , which decreases with increasing inner ratio ₁. The loop also shrinks, and the defect center deviates from the middle of the system, which is a non-planar structure. The deviation decreases with decreasing or increasing ₁, implying that the system tends to be a planar cell. Two models were then established to analyze the combined effect of non-planar geometry and electric field. The common action of these parameters facilitates order reconstruction, whereas their opposite action complicates the process.
基于二维朗道-德热纳张量形式，采用有限差分迭代方法，研究了向列型液晶中螺型位错环（s = ±1/2）在两个同轴圆柱之间的动力学行为。利用不同的(r_1)值模拟了厚度（(d = r_2 - r_1)，其中(r_1)和(r_2)分别表示圆柱腔的内半径和外半径）对缺陷指向矢分布的影响。结果表明，在(d)的临界值处发生序重构，该临界值随内半径比(r_1)的增加而减小。环也会收缩，缺陷中心偏离系统中部，这是一种非平面结构。偏差随(d)的减小或(r_1)的增加而减小，这意味着系统趋于成为平面单元。然后建立了两个模型来分析非平面几何形状和电场的综合作用。这些参数的共同作用促进了序重构，而它们的相反作用则使过程复杂化。
