Cano technique

All spectroscopic methods for an evaluation of the pitch lead to the size of the repeat distance of the supermolecular LC structure and the handedness of the twisting, although in UV-VlS spectroscopy, circularly polarized light has to be used. With some skill, the Cano technique may also result in the twisting sense of the helicoidal structure. 

Figure 9. Twisting power of a mixed solvent system CTC/DEME-r 2-pentanone (c = 0.8g/ml, 7=298 K spectroscopic method, Cano technique) X2 p volume fraction of 2-pentanone (adapted from...

Bamford, S.A., D. Wegrzynek, E. Chinea-Cano, et al. 2004. Application of X-ray fluorescence techniques for the determination of hazardous and essential trace elements in environmental and biological materials. Nukleonika, 49 87-95. 

Tinoco-Garcia, L. Cano-Dominquez, J. L., "A New Technique for Solving Multi-Phase Equilibria",... 

MOX is a technique that was developed in the Madiran region of southern France in the 1980s and was commercially released in 19% (Cano-Lopez et al., 2006). Its principle is the continuous delivery of a small metered amount of oxygen into a wine by means of micro-bubbling using a porous micro-diffuser. 

Figure 11 shows the dependence of the critical unwinding voltage Vf on the cell thickness-to-pitch ratio for a cholesteric layer with perpendicular boundary orientation. For these measurements two reusable cells, having thicknesses of 7.8 and 10.9 ym, were filled with various mixtures of the nematic liquid crystal RO-TN-103 and the chiral substance CB 15.We used the Cano wedge technique to determine the pitch of the mixtures and found the simple inverse relationship... 

The Cano-wedge method is an experimental technique to measure the pitch of cholesteric Uquid crystals. It consists of a flat substrate and a hemisphere with a cholesteric Uquid crystal sandwiched between them as shown in Figure 1.22(a). At the cento, the spherical surface touches the flat surface. On both the flat and spherical surfaces there is a homogeneous alignment layer. The intrinsic pitch of the Uquid crystal is Pg. Because of the boundary... 

The helical pitch of the SmC phase and its lyotropic analog can be measured by several methods. In this thesis two of them were used to double-check the obtained results. The first applied technique is the so-called direct method [7], which requires an orientation of the layer normal k normal to the direction of observation ( planar alignment ). The second one is the Cano method [7, 8] in which the layer normal k has to be parallel to this direction ( homeotropic ). 

Figure 8. Schematic diagram of the Cano-wedge technique for measuring the pitch, wherep=2lxa=2lhlL, in a chiral nematic (see text).

Figure 9. Typical Cano-wedge textures for a chiral nematic. The Grandjean-Cano disclination lines occur at the blue-yellow interface. The slightly curved distortion shows how sensitive the technique is to undulations in the glass of the wedge cell used here.

Another good example, using similar sandwich panel and paste bonding techniques, is the construction of the canoe-shaped fin-tip radomes for the Nimrod. 

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