Textures displays

The textures in homeotropic lamellar phases of lecithin are studied in lecithin-water phases by polarizing microscopy and in dried phases by electron microscopy. In the former, we observe the La phase (the chains are liquid, the polar heads disordered)—the texture displays classical FriedeVs oily streaks, which we interpret as clusters of parallel dislocations whose core is split in two disclinations of opposite sign, with a transversal instability of the confocal domain type. In the latter case, the nature of the lamellar phase is less understood. However, the elementary defects (negative staining) are quenched from the La phase they are dislocations or Grandjean terraces, where the same transversal instability can occur. We also observed dislocations with an extended core these defects seem typical of the phase in the electron microscope. 

Fig. 9-10. Representative thermal polarized optical micrograph of the nematic schlieren texture displayed by 13 ( = 5) on cooling from the isotropic melt to 159 C.

Because of its rotational symmetry a pole figure of a fiber texture displays redundant information, in the sense that the pole density along any longitude line (meridian) is the same as along any other. Thus a plot of pole density vs. angle between 0 and 90° is a simpler description of the texture for the texture shown in Fig. 9-8, such a plot would show a single maximum at 54.7°. 

Fig. 9-15. Representative thermal polarized optieal micrograph of the focal-conic texture displayed...

Electro-Optic Properties of Polymer Stabilized Liquid Crystals. Polymer networks have been used to stabilize many of the liquid crystal display states in various types of displays quite advantageously. In this section, we present some recent work on correlating the material properties of the liquid crystal/polymer network composite to the electro-optic properties of the flat-panel displays specifically cholesteric texture displays (75) and simple nematic birefringent type displays (7(5). 

In Fig. 5.32b the striped texture of the lyotropic SmC phase with formamide as solvent can be seen. The stripes appear much more visible in this sample, clearly indicating the macroscopic heUcity of the lyotropic phase. The helical pitch of p = 5.2 pm is close to the value found in the mixture with water. However, there is one significant difference between the two solvents While the sample with water had to rest for several weeks before the striped texture could be detected, the sample with formamide only took seconds after the transition into the lyotropic SmC analog phase to show the texture displayed in Fig. 5.32b. This difference in the time-based evolution of the helical director configuration is quite remarkable and implies that the solvent plays a very important part in the formation of the helix, even though it has only littie impact on the absolute value of the helical pitch. Possible explanations might be the more extended solvent layer in the case of mixtures with water or a different internal structure in the solvent layer. However, these points are only speculations and the reason for the deviating behavior still has to be understood. 

To display properties on molecular surfaces, two different approaches are applied. One method assigns color codes to each grid point of the surface. The grid points are connected to lines chicken-wire) or to surfaces (solid sphere) and then the color values are interpolated onto a color gradient [200]. The second method projects colored textures onto the surface [202, 203] and is mostly used to display such properties as electrostatic potentials, polarizability, hydrophobidty, and spin density. 

Lyotropic liquid crystalline nanoparticles have also been described. Concentrated solutions of gold nanorods in water in the presence of a surfactant (cetyltrimethyl-ammonium bromide) display a nematic mesophase stable up to 200 °C [74[. The N mesophase was identified by optical microscopy by their typical nematic droplets texture. 

Caseins, however, do not display a distinctive conformational transition upon denaturation and texturization they are considered a family of natively unstructured proteins (Farrell et ah, 2006a,b). 

The catalytic activity of hierarchical and conventional Beta zeolites for acylation of 2-MN is displayed in Figure 2(a) The Beta (PHAPTMS) sample shows a superior catalytic activity than the conventional one, due to its enhanced textural properties. In this case, the bulky nature of both substrate and products may cause the existence of diffusional problems inside the zeolitic channels, which are attenuated in the modified Beta sample due to the presence of the hierarchical porosity. Regarding the product distribution (Figure 2(b)), two main products are observed and a third isomer, 8-A,2-MN isomer is produced just in minor amounts. Interestingly, the selectivity towards the desired isomer increases in the material obtained from silanized seeds, reaching values around 75%. Probably, the active sites located on the surface of the secondary porosity are able to catalyze also the formation of 6-A,2-MN by transacylation. However, this reaction is expected to be strongly hindered in the conventional Beta zeolite since it requires the participation of two bulky molecules as reactants. 

As displayed in Figure 4, basalt, gabbro, and peridotite has distinctly different spectral signature and shows texture variations between different rock types. 

Figure 9. Top Two tetraurea calixarene monomers connected by a rigid spacer at their bottom rim display diverging hydrogen-bonding sites ideally suited for polymerization. The polymer (53) bears capsules of ca. 1.6 nm x 2.2 nm dimensions like beads on a string. Bottom Photomicrographs of typical Schlieren textures of 53 in chloroform (top row, left) and p-difluorobenzene (top row, middle) as viewed...

The bicubic patches are characterized with different colors, intensities and line textures to show attributes such as hydrophobicity and steric properties. Only one attribute may be displayed at a time, with color and intensity representing the value of the attribute, and line texture representing karma s confidence level in the information. For example, when displaying hydrophobicity, red patches are hydrophobic space while blue patches are polar space. Patches drawn with solid lines represent areas which are well explored while patches with short dashes contain little information. Displaying information using multiple cues a ows the user to examine various aspects of the surface model without having to deal with large amounts of numerical data. 

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