AFLCs

Fig. 1.34 Corrosion and passivation of Fe-18Cr-SNi stainl s steel. Potentiosiatic anodic curve JKLM, hydrogen evolution reaction, curve Hl low concentration of dissolved oxygen, curve t> FG, high concentration of dissolved oxygen, curve AflC (Section 3...

CIWMB, Alternative Final Landfill Covers (AFLC), California Integrated Waste Management Board, April, 2005. Available at www.ciwmb.ca.gov/LEACentral/AFLC, 2009. 

AFLC Test Range Complex, UT 7.8 1.4 27 53 20 Clay loam... 

Photochemical polarization flip was immediately extended to antiferroelectric LCs (AFLCs), and it was found that in azobenzene guest/AFLC host systems, polarization flip could be induced photochemically and effectively, as shown in Figure 3.1331 Novel photochromic molecules to induce polarization flip effectively have been explored, and molecular design on the basis of large Ps resulting from chiral cyclic carbonates has been found to be quite effective. An azobenzene dopant containing a... 

The fcactioo of CpCot with bcnzocydobutenedione gives a phihaloylcobih complex in high yield (98%) reaetton of (bis complex with aflc oes results to complexes of naphthoquinmies/... 

The specific rotation at a given wavelength is defined as [a] = aflc... 

An unusual effect was observed in an antiferroelectric liquid crystal (AFLC) [116-125]. The switching is associated with the appearance of the third state, in addition to the two bistable up and down states known for the Clark-Lagerwall effect. The corresponding hysteresis of electrooptical switching is shown in Fig. 7.23. We can see that the third state at the zero field is stable, and can be transformed either into up or down states if not applying a rather high switching field. 

The FLCs or AFLCs mentioned above are liquid crystalline materials showing a chiral smectic C phase or related phases. Although nematic liquid crystal possesses only directional order, smectic liquid crystals shows layer structures or periodic order of the liquid crystalline molecular centres. In this respect, smectic liquid crystalline materials have more in common with crystalline materials than with nematic liquid crystalline materials. As a result, the alignment of smectic liquid crystal is quite different from that of nematic liquid crystals. Smectic liquid crystals show a large variety of defects because they possesses highly ordered structiu-es. Moreover, the layer structures are irreversibly destroyed by applying stress. This phenomenon poses a major problem for display applications. Therefore, several techniques to prevent the application of force to the liquid crystalline materials of FLC or AFLC devices have been proposed. 

In the sections on smectic liquid crystals, first the alignment and molecular orientation of surface stabilized ferroelectric liquid crystals (SSFLCs) are treated in detail. Next, the alignment technologies needed for the occurrence of bistability are detailed. Furthermore, liquid crystalline devices made of AFLC materials and the applications of FLC and AFLC materials to active matrix devices are discussed. 

Another interesting technology involves a novel method of FLC and AFLC orientation that also applies a polymer-wall structure. Minato etal. have reported that they were able to obtain uniform orientations by appl5ring a temperature graduation method to FLC panels with polymer walls [37]. This method utilizes the reduction of volume on partial cooling and is able to realize a uniform C2 orientation and a uniform alignment with antiparallel rubbing, etc. 

The layer-rotation phenomenon is one of the unique behaviours of FLC and AFLC devices. It is caused by the presence of spontaneous polarization. 

Pig. 6.2.2 The alignment structure of an AFLC with and without applied voltage. 

Fig. 6.2.3 Concept for the driving method to realize grey scale expression using AFLC tristable switching.

To obtain high contrast, AFLC alignment without defects must be realized. Moreover, to realize the stable grey scale expression of the high duty ratio by simple matrix driving, large hysteresis and sharp threshold characteristics are indispen-sible. These characteristics are determined not only by the AFLC material properties, but also by the quality of the alignment states. 

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