Materials Literature
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The possible effect of different salinities on the valve morphology of the marine centric diatom Thalassiosira decipiens was investigated. Cultures were grown in media of salinities ranging from 2 to 35%. for 40 days. Only the 15, 20, 25, and 30%. cultures had sufficient growth for statistical analysis of population d…
For the first time carbohydrate derivatives were systematically studied as doping material for a liquid crystalline phase. These compounds can exhibit a large twisting power. It may be controlled by the configurations of single chiral centers. Thus, a series of phenomena are realized in the cholesteric phase such as h…
We have used a membrane-leak mass spectrometer to follow the time courses of H2 evolution and substrate reduction by nitrogenase [reduced ferredoxin:dinitrogen oxidoreductase (ATP-hydrolyzing), EC 1.18.6.1]. In the absence of added substrates, dinitrogenase passes all of its electrons to protons to form H2, but when a…
The rapid progress of the young liquid crystal display (LCD) technology is due to the synergisms resulting from combining research on electro-optical effects, liquid crystal materials and display technology. The design and production of liquid crystal molecules with specific physical properties and their application i…
A problem in controlled release pharmaceutical systems is formulated and studied. The device modeled is a polymer matrix containing an initially immobilized drug. The release of the drug is achieved by countercurrent diffusion through a penetrant solvent with the release rate being determined by the rate of diffusion…
Abstract An experimental study of binary and ternary phase equilibrium in the system polycaprolactone (PCL) poly(vi‐nylchloride) (PVC)‐77/23 styrene‐acrylonitrile copolymer (SAN) is described. Miscibility is determined using differential scanning calorimetry (DSC) and turbidity. PCL/PVC and PCL/SAN are largely miscibl…
The titanyl complex, TiO(C22H22N4), a complex of the ligand (I) obtained by the hydrolysis of the corresponding dichloride, has a reactive Ti=O function which readily interacts with other metal species forming μ-oxo heterobinuclear dimers. In these adducts, the Ti=O functions as a base toward oxophilic metal centres s…
SUMMARY Previous investigations had shown that about 80 years of Norway spruce monoculture on an ochreous brown earth of the Belgian Ardennes were sufficient to accentuate the weak podzolization process already present in the climax beechwood soil and to increase the weathering of several minerals, e.g. 2:2 clay miner…
The crystal structures of the minerals in the cuspidine-wohleritc- lavenite group can be described in terms of two kinds of modules whose connections form the structures of the various phases: "octahedral walls" four columns wide and running along c, and diorthosilicate groups. The octahedral walls are interconnected…
This book presents the highlights of modern solid state chemistry, an emerging area of chemical science. In adopting a unified and up-to-date approach the authors take the reader to the very frontiers of the subject, which is concerned primarily with new methods of synthesis, identification and characterization of sol…
Porous Vycor glass has been impregnated with selenium and tellurium by pressure forcing the nonwetting semiconductor melt into the interconnected pores. Dense semiconductor microstructures with a characteristic size of 50 Å can be fabricated by this technique. Measurements are reported which show the composite is suit…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAn AM1 theoretical study of the structure and electronic properties of porphyrinCharles H. ReynoldsCite this: J. Org. Chem. 1988, 53, 26, 6061–6064Publication Date (Print):December 1, 1988Publication History Published online1 May 2002Published inissue 1 December 1988https://…
The failure of metal structures in contact with natural, untreated waters is frequently ascribed to bacterial corrosion.1This study compares the corrosive effects of Vibrio natriegens (V.natriegens) when in batch and continuous flow culture. Evidence is presented for enhanced corrosion of carbon steel resulting from “…
ABSTRACT The marine diatom Ampbora coffeaeformis is positively chemotactic to glucose and sugars of similar structure. A free hydroxyl group is required at the 2-position of the ring; however, D-mannose (a toxic sugar) and L-glucose promote negative chemotaxis. Sugar metabolism is not necessary for a chemosen-sory res…
The electrochemistry and spectroelectrochemistry of mononuclear, binuclear and tetranuclear zinc neopentoxy-substituted phthalocyanines are presented. The binuclear and tetranuclear species show two oxidation waves to the radical cation indicating the existence of stable mixed-valence, half-oxidized species. The elect…
The Landau theory of cholesteric blue phases (BP) is reviewed. The emphasis is on basic concepts, including (1) why BP appear between the disordered and ordinary helicoidal phases at sufficiently short pitch, and (2) why there are several cholesteric BP with different structures. These and other results in agreement w…
This is a study of a group of Czochralski grown rare‐earth‐doped Y 2 SiO 5 single‐crystal cathodoluminescent phosphors. Such dopants as Ce 3+ , Tb 3+ , Eu 3+ , Sm 3+ , Tm 3+ , Gd 3+ , and some of their combinations were investigated. Activation by ( Ce 3 + + Gd 3 + ) , ( Tb 3 + + Gd 3 + ) , and by ( Tb 3 + + Eu 3 + )…
We present a detailed study of self-phase modulation in nematic liquid crystals, performing a quantitative comparison with the theory of diffraction. A quite satisfactory fit is obtained at low optical power by taking into account only orientational effects, as it is found that experimental observations are affected b…
Abstract Surface‐enhanced Raman scattering (SERS) of [HVO 4 ] 2− , [HPO 4 ] 2− and [HAsO 4 ] 2− has been studied on silver sol in H 2 O and 2 H 2 O; in H 2 O the spectra were recorded from pH 3 to 12 with excitation at 488.0, 514.5, 568.2 and 647.1 nm. Considerable enhancement was observed compared with conventional R…
Analogies between thermotropic and lyotropic Liquid Crystals were underlined at the earliest time of their investigation, since “smectic” is an old concept shared by the two domains. However, during the last decades, the differences between thermotropic and lyotropic systems were emphasized more than their similaritie…