Materials Literature
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Penta-, hexa- and hepta-alkoxy derivatives of triphenylene can be smoothly mono-nitrated in high yield to give novel discotic liquid crystals with enhanced mesophase properties. We have investigated the regiochemistry of these reactions which appear to be controlled by a combination of steric and electronic factors. N…
When fabrics are coated, their deformation behaviour changes considerably. The tensile, shear, and bending properties of four typical coated fabrics have been measured using the FAST system and an Instron tensile machine. The fabrics were measured before coating, after coating and after subsequent stretching or sheari…
Catalysts have been prepared by the incipient wetness method and characterized by 31P MAS NMR spectroscopy. Two species, i.e. the interacting molecular and the crystalline, were found in both the supported PMo12 and supported PW12 catalysts. Experimental results indicated that the interacting species are more thermall…
A microemulsion has been studied as a reaction medium to control the coprecipitation of oxalate precursors of the superconducting YBa2Cu3O7 -δ ceramics. The oxalate coprecipitation of Y, Ba and Cu from nitrate solution was studied on basis of computer modelling of equilibrium systems. The optimum operating conditions,…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis of Reactive Functionalized Oligo(p-phenylene sulfide)sEishun Tsuchida, Kimihisa Yamamoto, Kenichi Oyaizu, Fumiaki Suzuki, Allan S. Hay, and Zhi Yuan WangCite this: Macromolecules 1995, 28, 2, 409–416Publication Date (Print):January 1, 1995Publication History Publis…
The Raman spectra of three samples of holmquistite, a lithium-containing orthorhombic amphibole, from Bessemer City (NC, USA), Barraute (Quebec, Canada) and Brandgraben (Austria), have been measured by Raman microscopy. The OH-stretching region is characterised by bands around 3660, 3645, 3635 and 3615 cm assigned to…
Summary The cell wall of stem fibers of flax shows the classical cellulosic architecture with three main domains with constant slope (S1, S2- thickened and locked into an almost axial direction -, S3) within which the microfibril orientation remains parallel (unidirectionnal, the so-called “spiral texture”). The prese…
In a one-pot reaction, transition metal substituted polyoxomolybdates are shown to be bifunctional catalysts for epoxidation of alkenes by via oxygen transfer from intermediate alkylhydroperoxides; the latter being formed by catalytic autoxidation with molecular oxygen.
Abstract The understanding of the failure mechanism causing cracks in insulated telephone wire is critical to developing a solution to the problem. This paper reviews the antioxidant and metal deactivator theory as it applies to polyolefins and reviews the factors, both internal to the polymer and external which affec…
The usefulness of time-resolved measurements is shown for the study of degradation processes of insulating materials associated with partial discharges. Using an optimised test set-up the different stages in the degradation process can be recognised. The possibilities for using the time-resolved method in practice are…
Mo-doped and Mo:Sb-doped SnO2 were made via the inorganic sol-gel route from the corresponding metal chloride precursors and the films were deposited by dip-coating technique. Films with a thickness of 100–170 nm were made by single dipping and the corresponding charge capacities were in the range 6–11 mC cm–2. The fi…
4,4′-Bipyridyl is an efficient template for the formation of cyclic porphyrin dimer from a diethynyl porphyrin monomer; s-tri(4-pyridyl)triazine promotes the formation of cyclic trimer from the same starting material to a lesser degree whereas meso-tetra(4-pyridyl)porphyrin is not a practical template for the preparat…
Colloidal dispersion and pressure-casting to prepare SiC green pieces of two types and pressureless sintering of SiC were sequentially conducted to obtain homogeneous, dense SiC bodies. Polyethyleneimine (PEI) was selected as a dispersant, and Al2O3/Y2O3 additives served as a sintering aid for the ceramic systems. The…
Effects of cold work on hydrogen (H) transport, H concentration, and H embrittlement (HE) in type 1020 steel (UNS G10200) exposed in a sour environment were examined. Cold work decreased H diffusivity and increased H concentration in the steel. The increase in dislocations as a result of cold work was responsible for…
A semi-empirical model for high-field conduction in polyethylene is developed on the basis of data in the literature for ac conductivity in the range of 30 to 60 kV/mm and 'charge injection' from a needle in the range of 160 kV/mm. The model is used to compute high-field conduction-related phenomena by solving Poisson…
The efficient synthesis, molecular and crystal structure, chemical, spectroscopical and electrochemical properties and charge-transfer salts of dimethyl[2,4-dioxo(1H,3H)pyrimido]tetrathiafulvalene, a novel π-electron donor able to form intermolecular hydrogen bonds of nucleic acid base-pair type, are described.
High-surface-area zinc–cobalt–aluminium oxides have been prepared from coprecipitated hydroxycarbonate precursors. The oxides were tested for their H2S uptake in a microreactor at 303 K. The precursors all adopted a hydrotalcite-type structure, whilst the oxides were also all single-phase materials. Their structures w…
Reaction of CuCl2·2H2O or CuBr2 with the tridentate ligand 4-methyl-2,6-bis(pyrrolidin-1-yl-methyl)phenol (Hmbpp) in methanol yielded two copper(II) complexes [Cu4OCl4(mbpp)2]·2MeOH 1 and [Cu4OBr4(mbpp)2]2. They were characterised by single-crystal X-ray diffraction analyses. Both structures were solved using direct m…
Molten decanoic acid, capric acid, reacted with the layered double hydroxide (LDH) of initial composition Mg6Al3.4(OH)18.82(CO3)1.51(NO3)0.36·4.5 H2O, at a temperature of 150 °C using a heating rate of 1 °C min–1. Powder X-ray diffraction (PXRD) showed that the reaction products were microcrystalline. The polyphasic n…
Copper hydride, CuH, has been prepared by the reduction of aqueous copper sulfate using hypophosphorous acid. The polycrystalline red–brown hydride has been analysed using transmission electron microscopy, powder X-ray diffraction (PXRD) and differential scanning calorimetry, and consists of agglomerates of needle-lik…