Orientation homogeneous

Figured. Polarities of the homogeneous orienting field and channeltrons used for the 0° and 180° configurations. The orientation of the polar molecule is indicated for each configuration using CH3Br and Cp3Br as examples.

When an alternating electric field is applied to a homeotropically oriented layer of LC melt at definite temperatures (close to Tcl), a homogeneous orientation is... 

Frozen-in stresses due to molecular orientation may also be measured by this technique, since oriented polymers shrink rapidly above the softening temperature. Non-homogeneously oriented parts cause deformations. 

I /I )2 should be an increasing function of L. One has to keep in mind that due to a two-dimensional orientational distribution function of the in-plane molecular alignment, the contribution of / normalized to the total intensity / +ij, a=/ /(/ +/j ) differs from one even for a homogeneously oriented device, as for example a = 0.75 with S — 3. It is clear that the experimentally observed EL anisotropy plotted against the distance, x, from the A1 cathode (located at x = 0), and identified with varying thickness (L) of parallel oriented n monolayers, contains the EL emission profile determined by the spatial distribution of emitting states, x(x) ... 

Many of the disadvantages of ram extrusion are eliminated in hydrostatic extruaon, where the piston is replaced by high pressure fluid. As shown in Fig. 15, the billet stands clear of the cylinder walls, so that this element of friction is eliminated. The pressure transmitting fluid also lubricates the interface between the die and the billet, so that the deformation is essentially plug-flow (i.e. an extensional deformation, identical to drawing polymer with a free surface). Homogeneous oriented sections are therefore produced. A small haul-off force is applied to provide control of the extrusion process, and this also serves to ensure that the extrudates are straight. 

Fig. 10 Alignment of the LC a) spontaneously they lie parallel to most surfaces b) surface treatment such as rubbing promotes a homogeneous orientation parallel to the surface c) adsorption of surfactants lead to homeotropic (perpendicular) orientation.

The decrease of the orientation rate with the decrease of temperature seems to be related to the increase of the viscosity of the LC melt. The absence of the initial homogeneous orientation of the polymeric liquid crystal in the electro-optical cell implies that the average viscosity of the LC polymer is the important factor, instead of the rotational viscosity. 

Schlieren textures are very common in liquid crystals and are usually easily identified and classified. These patterns are observed in homogeneously oriented nematic phases and for smectic phases where the long axes of the molecules are tilted with respect to the layer planes and the layers are arranged parallel to the surface of the glass. Thus, schlieren textures occur for the nematic phases of both calamitic and discotic materials, and for the tilted smectic phases C, I, and F. 

Smectic LC gels also exhibit two types of transitions [21]. For Type II, aligned fibrous aggregates of ZI18 are formed in the homogeneously oriented smectic A phase of the liquid crystal in a parallel rubbed cell (Fig. 6a) [21]. The direction of aligned fibers is perpendicular to the molecular orientation... 

Fig. 24. a) light microphotography of suboptimal drawn PET fibers with pronounced stripes due to enhanced destructive processes b) polarization microphotography of similar objects c) polarization microphotography of not homogeneous oriented sections d) similar objects with filler defects. 

W. Maior and G. Meier, A simple theory of the dielectric characteristics of homogeneous oriented crystalline-liquid phases of the nematic type, Z. Naturforsch, A 16, 262 (1961). 

Maps of the homogeneous orientation work spaces of different robot architectures using pivot and parallelogram substructures on the x-z plane. 

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