Materials Literature
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The material (R)-1-methylheptyl 4-(4′-n-dodecyloxybiphenyl-4-ylcarbonyloxy)-3-fluorobenzoate has been prepared and its liquid-crystalline properties investigated. This material was selected for synthesis because it was expected to exhibit a ferroelectric smectic C* phase with a large value for its spontaneous polariza…
The interaction of AlMe3 with the polydialkylsiloxanes (OSiRMe)x and (OSiPh2)3 for long periods at elevated temperatures leads to the rupture of the silicon–oxygen framework and yields dimeric dimethylaluminium siloxides [Me2Al(OSiMe2R)]2, R = Me (1), n-C6H13(2), n-C8H17(3), n-C14H29(4), n-C18H37(5), -CH2CH2CF3(6), Ph…
Abstract On the basis of sterical and electrostatical arguments, it is deduced that the stoichiometry of Na + ‐ and CO 3 2‐ ‐containing calciumhydroxyapatite can be accounted for by 6 substitution mechanisms magnified image where V x stands for a vacancy in the X‐sublattice. It is shown that every mechanism proposed i…
Expressions to describe the initial collection efficiency of electret filters for both charged and neutral particles were derived covering a wide range of Coulombic force and induced force parameters including the interceptional effect. The prediction equations were in good agreement with the experimental data. Furthe…
The binary lyotropic liquid crystalline system caesium pentadecafluoro-octanoate (CsPFO)/water (2H2O) exhibits an isotropic micellar phase, a lyotropic nematic phase and a positionally ordered, lamellar phase whose planes contain substantial water filled defects. It has been suggested that the structural unit in all t…
A simple and accurate method for determination of filler material density is described. Rice husk ash (RHA) which consists predominantly of silica serves as a filler in polypropylene. The filler density was determined from first principles using a pyknometer. The filler was compounded in polypropylene and the densitie…
A palladium-catalysed stannole synthesis is described and its mechanism elucidated by the synthesis of several conceivable intermediates, which have been fully characterized (NMR, X-ray structure analyses).
A review is presented of microhardness tests applicable to plastics. The methods are outlined and the effect of test variables considered. Published literature describing applications of microhardness measurements to plastics including structure and environmental resistance are reviewed.
A series of [3]- and [4]-dendralenes, functionalised with 1,3-dithiole groups, are synthesised and shown by cyclic voltammetry to undergo reversible multi-stage redox reactions to yield tri- and tetra-cation species, respectively; the X-ray crystal structure of a [3]-dendralene derivative is reported.
Abstract A formula to compute total elastic Mott cross‐sections as well as a tabulation of the constants to compute total Mott cross‐sections for 94 elements are presented herein. This formula and the constants have been obtained from the values of total elastic Mott cross‐sections computed by Czyżewski et al. (1990)…
The use of the typical ABC equivalent circuit for one cavity in solid dielectrics for internal partial discharge modelling has been common practice for many years. The introduction of an equivalent circuit for two closely coupled cavities permits the investigation of the interaction between discharges in such cavities…
Upon doping with C60–C70(75 : 25 by mole) or by C60(>99%) in N-methylpyrrolidin-2-one–toluene solution at room temperature, conductivities of the emeraldine base of polyaniline as free-standing solution-cast films were found to increase significantly toca. 10–4 S cm–1 at a fullerene content of ca. 1 mol%.
A new test for estimating the adhesion of paints to metal substrates is presented. Small painted disks are immersed in N-methyl pyrrolidone (NMP) at 60°C and the time for the paint film to dclaminate completely and intact from the substrate is recorded. This time, termed the NMP paint retention time or NMPRT, is shown…
A series of aroylhydrazinato-nickel(II) and -copper(II) complexes have been synthesised in high yield and shown to form a new class of metallomesogens, which form smectic C and nematic phases; the nickel(II) complexes were found to be highly stable even in the isotropic phase, which contrasted with the rapid decomposi…
Vinyl polymers containing oligothiophenes, e.g. 2,2′ : 5′,2″-terthiophene and 2,2′ : 5′,2″ : 5″,2‴-quaterthiophene, as pendant groups have been found to constitute a novel class of potential electrochromic materials. The electrochemically doped polymers undergo reversible, clear colour changes from bluish purple to pa…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNew strontium borate halides: Sr5(BO3)3X (X = F, Br)Theodore Alekel III and Douglas A. KeszlerCite this: Inorg. Chem. 1993, 32, 1, 101–105Publication Date (Print):January 1, 1993Publication History Published online1 May 2002Published inissue 1 January 1993https://pubs.acs.or…
Hydrogen bonding between ions has been used to engineer specific structural features into two novel crystalline materials with nonlinear optical properties, (S)-1-phenylethylammonium 3-hydroxybenzoate and (S)-l-phenylethylammonium 4-hydroxybenzoate; their crystal structures are reported and the importance of their hyd…
The operation of water reactor nuclear power plants provides a significant fraction of the world's electric power generation. At the end of 1992, approximately 360 such plants were in operation, representing a total generating capacity of 320 GWe. As these plants age, and as new designs evolve, the impact of environme…
The symmetry of the graphite crystal implies that each carbon atom has an electric quadrupole moment associated with it. This atomic moment may have a significant influence on the location of adsorbed molecules on a graphite surface and on the adsorption energy. A novel experiment, involving the measurement of the eff…
Various pure and yttrium-containing alumina aerogels have been synthesized and characterized by different techniques. The presence of yttrium promotes the thermal resistance of solids, as demonstrated by X-ray diffraction (XRD) and Brunauer–Emmett–Teller (BET) surface measurements. Yttrium allows the aerogel structure…