Materials Literature
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Fourier transform infrared absorption (FTIR) spectroscopy has been used to study a discotic liquid crystal. IR spectra are reported as a function of temperature for hexapentyloxytriphenylene (H5T). The order parameter S has been determined using unpolarized radiation and by comparing the spectra of the discotic phase…
The aerospace and naval industries both have a need for lightweight materials that can operate under extreme conditions, and yet retain their basic mechanical properties for long duration. Many of the papers presented in STP 1174 address on-going research
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotochemistry of axially chiral (arylmethylene)cycloalkanes: a search for suitable photoswitchable liquid crystalline materialsRobert P. Lemieux and Gary B. SchusterCite this: J. Org. Chem. 1993, 58, 1, 100–110Publication Date (Print):January 1, 1993Publication History Publ…
A two-dimensional computer analysis of the surface charging on angled insulators has been performed by using the Monte Carlo simulation method. Results are compared to the charge in equilibrium model, originally proposed by C.H. de Tourreil and K.D. Srivastava (1973).>
Abstract The synthesis of the octasubstituted phthalocyanine 1 , highly soluble in organic solvents, is described. Its aggregation properties in different solvents and in the presence of alkaline, alkaline earth, and ammonium salts are studied.
The structures of Ca0.5Ti2P3O12 and Sr0.5Ti2P3O12, low-thermal-expansion materials, have been refined by the Rietveld method using high-resolution powder X-ray diffraction (XRD) data. The assignment of space group R to NASICON-type compounds containing divalent cations is confirmed. 31P magic-angle spinning nuclear ma…
Hysteresis of the contact angle, i.e. the difference between the advancing and receding contact angles, is discussed in terms of the liquid film presence behind the drop when it has receded. It is shown that values of receding contact angles in many systems result from a well-defined free energy balance in the solid/l…
We report the oxygen-induced polymerization of anilinium to poly(aniline) in the layered compound (C6H5NH3)0.4V2O5·0.40H2O forming {1/n(–C6H4NH–)nV2O5·0.40H2O.
Electro-optical properties of polymer dispersed liquid crystal (PDLC) films which have reversed morphology are investigated. Highly transparent memory states, for which transmittances exceed more than 80 per cent, are observed in these PDLC films. The saturation voltage V 90 can be decreased by a PTF (a phase transiti…
Abstract This article describes the synthesis and thermal characterization of novel aryl‐substituted rod‐like homopolyimides. Synthetic aspects of monomer syntheses and one‐step polymer synthesis in m ‐cresol are presented. Polyimides with rod‐like chain structure are based on monophenylated pyromellitic dianhydride (…
The complexes of general formula [Ni(L)(N3)][ClO4](L is meso-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane or 2,3-dimethyl-1,4,8,11-tetraazacyclotetradeca-1,3-diene), have been characterized by X-ray crystallography; both are chains in which the nickel(II)–tetraammine fragment is bridged by one µ-azido l…
Tetra-p-aminophenylporphyrin (TPP) was conjugated with gadolinium diethylenetriaminepentaacetic acid (DTPA) and used as a contrast agent in magnetic resonance (MR) imaging to achieve tumor selectivity in nude mice. A substantial decrease in T1 was measured in excised tissues (kidneys, tumor, and liver) from mice that…
Many liquid crystals are found to have relatively high birefringence (Δn) values in the microwave and millimeter wave regions, as calculated from the phase shift induced by their reorientation by magnetic or electric fields. At 30 GHz, Δn values were obtained in the range of 0.08 to 0.18 for eleven liquid crystal mixt…
We report measurements of the temperature variation of the flexoelectric coefficient (e 1–e 3) of a number of nematic liquid crystals like phenylcyclohexanes, cyanobiphenyls, etc. We have also measured (e 1+e 3) of a few systems using appropriate methods of applying an electric field gradient to the sample. In most of…
This paper reviews liquid crystal optical devices including tunable filters, photonic switches and spatial light modulators, and examines their application to optical communication and information processing systems. Optical processing has three major advantages: massive parallelism, high speed and broad wavebands. Co…
In an effort to develop direct detection methods for Perkinsus marinus cells in host tissue and environmental samples, the production of both mono-and polyclonal antibodies specific for this apicomplexan oyster pathogen was attempted. A particulate hypnospore immunogen was isolated from infected oyster hemolymph follo…
Abstract Minimum necessary adaptations are described that are sufficient for obtaining very low energy electron micrographs (VLEEMs) from commercially available routine scanning electron micrographs (SEMs) with the electrons accelerated to an energy of the order of tens of keV. A cathode lens inserted into the specime…
Infrared spectroscopy is used to characterize the hydroxyls of HEMT and the interactions with benzene of these hydroxyls and of Na+ cations in NaEMT. Benzene adsorption studies reveal that HEMT is a stronger solid acid than HY or HSAPO-37 and that ca. 55–65% of the theoretical protons are still present after evacuatio…
Tetra-tert-butylphthalocyaninatonickel is synthesized from phthalic anhydride as well as from phthalodinitrile and nickel chloride, whereby a mixture of four different structural isomers are obtained; two of these isomers, with C2v-and Cs-symmetry are isolated for the first time by HPLC and medium pressure liquid chro…
A short and efficient synthesis of N, N, N′, N′-[2,6-bis(3-aminomethyl-1-pyrazolyl)pyridine]-tetrakis(acetic acid)(6), an analogue of terpyridine with additional chelating iminodiacetic groups, is described. Compound 6 forms stable complexes with EuIII and TbIII in water whose relative luminescence yields, excitation…