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Disc like molecule which was formed by fused polyaromatics was found to be with discotic liquid crystal properties. So it has been researched thoroughly. We take 5,6,11,12,17,18-hexaazatrinaphthylene (HTN) as our central core and synthesize Hexa-O-substituted hexaazatriphenylene, a new molecule with discotic liquid crystal properties successfully.

Abstract There are three focal points in this experimental study¡G(1)Change Reynolds number(Re) and measure the heat transfer coefficients on upper¡Bback¡Bside and front surfaces of a chip for standard height(20mm)¡F(2)Influences of the surface heat transfer coefficients when change the heights of a chip to 10mm and 30mm , then compare with the results of a chip with standard height¡F(3)Compare the heat transfer effects of a chip on different positions of the testing region. The range of Re is 2000~10000 in this experiment and the chip sets are installed on the testing board with a 3x4 array. According to similarity principles to setup whole experimental models¡Fassume this experimental system is a semi-infinite region and its heat transfer model is one dimension¡Fuse the transient heat transfer method with thermochromic liquid crystal as the surface thermometer , then we assemble micro video cameras in the experimental system to obtain the color changing images on chip surfaces. The software , LCIA (Liquid Crystal Image Analysis) , is used to analysis the changed color and the temporal history of the surface temperatures to determine the local heat transfer coefficients on chip surfaces. The results show¡G(1)The heat transfer coefficients on chip surfaces are increased with Re and effects of vortex¡F(2)Upper surface of the chip has the largest average heat transfer coefficient(h) , front surface and side surface have almost the same at lower Re , but at higher Re , of front surface is larger than side surface¡Fback surface has the lowest ¡F(3)When change the height of the first chip to 10mm , it has the best heat transfer effects at Re=2175 and 3257¡Fthere is almost the same effects at Re=4423 with different heights(10mm , 20mm and 30mm) and from Re=5535 to 9973 , this chip has the best heat transfer effects at 30mm. Then change the heights of the second and third chips , there are the best heat transfer effects at 30mm and the lowest at 10mm¡F(4)When fix heights of the chips at 10mm and 20mm , there are more better heat transfer effects as chips more close to the entrance of the testing channel , but once the heights of chips are 30mm , the positions of chips on the testing region are not very important influences to heat transfer effects.

This article reviews the properties and applications of a series of liquid crystal solvents for NMR spectroscopy of, particularly, biological compounds with emphasis placed on n-alkyl-poly(ethylene glycol)/n-alkyl alcohol, the most versatile liquid crystal system hitherto discovered. The applications of this solvent to mixtures, polymers and proteins are also mentioned.

The attenuated total reflection (ATR) due to excitation of surface plasmon is usually applied to study the dielectric coefficient. In this study the surface plasmon has been excited on the interface between the liquid crystal and silver in Krestchmann configuration. We can obtain the effective reflection index and the tilt-angle of liquid crystal anchored on the interface with the excitation condition of surface plasmon. We also discuss the variation of the tilt-angle of liquid crystal with the various applied bias.

Rubbing alignment has been used popularly in display industry. However, the alignment mechanisms of rubbed polymer are still not well understood. The purpose of this study is to investigate the relationship between anisotropy of rubbed polyimide thin film and liquid crystal alignment. In this study, we discuss the effects of surface energy and RAS on the surface roughness and pretilt angle of liquid crystal molecules. RAS is a non-contact optical probing technique developed originally for real-time, in situ monitoring of semiconductor growth . In this technique the normalized difference in reflectivity along two orthogonal directions is measured. Recently, the prospect of using RAS for process control in the fabrication of liquid crystal devices is investigated. On the other hand, we have known that the magnitude of surface energy is related to the strength of molecular bond. We can obtain the variation of surface properties by measuring the difference of surface energy. We found that the RA signal, pretilt angle and surface roughness are increasing with an increase in rubbing strength, but surface energy was decreased..

Filling the liquid crystals (LCs) into the air holes of the photonic crystal fibers (PCFs), we can obtain the liquid-crystal photonic crystal fibers (LCPCFs). Due to the tunable optical properties of the LCs, we can fabricate tunable optical devices based on the LCPCFs. In this thesis, we investigate the photonic bandgap (PBG) properties and find out the effective modal index curves of the LCPCFs by the finite-difference frequency-domain (FDFD) method. The effects of the operation temperature and the alignment of the LCs are discussed. When the alignment of the LC is in the transverse plane of the PCF, we can observe the blue shift and the splitting of the PBGs as we increase the operation temperature. As the LC is aligned along the PCF, the red shift occurs and the splitting disappears. The shift and the splitting of the PBGs are due to the high anisotropic property of the LCs. Besides, we can rotate the alignment of the LCs by the external electric field, and the effects of the alignment on the propagation properties of the LCPCFs are larger than those of the operation temperature. In the experiment, we successfully fabricate the LCPCFs by using the vacuum method. In the measurement of the LCPCF at different operation temperatures,the red shift of the spectra can be observed with the increasing operation temperatures, which has a very good agreement with the simulation results. As we vary the alignment of the LCs with the external electric field, the transmission bands are almost the same as the voltage is less than 200V. During the range of 200V to 400V, the PBGs demonstrate obvious variations and the deep appears at 1050nm. When the external electric field is raised to 400V, the shapes of the spectra are almost the same and the red shift of the PBGs can be observed. The results of our simulation and the experiment measurement can help us to design and fabricate optical devices based on the LCPCFs.

This study proposes a polarization-independent liquid-crystal Fresnel lens using twisted nematic liquid crystals (TN-LCs) with two electrodes structure. A photoresist type has high diffraction efficiency, high diffraction efficiency and good polarization independence characteristic. However, its diffraction cannot be completely switched off. A patterned electrode type has the characteristics of the switch-off and good polarization independence. However, it has low diffraction efficiency. We improve the patterned electrode type with two electrodes structure. Experimental results reveal that LC Fresnel lens using the TN-LC with two electrode structures has high diffraction efficiency and a good polarization-independent characteristic.

Thesis (M.S.)--Textile and Fiber Engineering, Georgia Institute of Technology, 2004. / Griffin, Anselm, Committee Member; Srinivasarao, Mohan, Committee Chair; Park, Jung O., Committee Member. Includes bibliographical references (leaves 101-105).

Thesis (Ph.D.)--Kent State University, 2009. / Title from PDF t.p. (viewed Feb 25, 2010). Advisor: Oleg Lavrentovich. Keywords: electro-optical applications of liquid crystals, beam steering devices, polarization rotator, negative refraction, electrically tunable lens, colloidal dynamics, bidirectional motion of colloidal particles in liquid crystals controlled by backflow. Includes bibliographical references.