Different Geometries. Simultaneous Action of Electric and Magnetic Fields

3 Different Geometries. Simultaneous Action of Electric and Magnetic Fields 

Prederiks transition of nematic liquid crystals, placed between two coaxial cylinders, was investigated in [9] (Fig. 4.3(a)). If the initial directors are aligned along the tangential lines, i.e., in a cylindrical coordinate system 

The electrooptical behavior of quasi-homeotropic oppositely pretilted nematic layers has been investigated [11]. In these layers, due to the boundary conditions 

For sufficiently small thicknesses, the quasi-homeotropic orientation spontaneously transforms to the homeotropic one that, perhaps, is the reason for the so-called spontaneous Prederiks transition, i.e., destroying the homeotropic orientation at a definite critical thickness in the absence of an electric field [12]. The physical reason for the latter phenomenon is weak anchoring on the boundaries [13, 14] and will be considered below. 

The hybrid (or homeoplanar) director profile was considered for both the field in the plane of the director distortion [15] and that perpendicular to it [16]. It was shown that in the latter case the effect is of a threshold character, and the threshold is lower than that for the homogeneous orientation [15]. 

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