Materials Literature
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Diamond has been synthesized from cyclic hydrocarbons under high pressures between 6 to 9GPa and high temperatures ranging from 710 to 1290°C. The result offers a clue to the genesis of diamond in the deep interior of the earth.
We describe the synthesis and crystallisation by means of chemical vapour transport reactions of TiPO 4 and VPO 4 . TiPO 4 ( a = 5.2985(5) Å, b = 7.911(1) Å, c = 6.3473(5) Å) and VPO 4 ( a = 5.2316(5) Å, b = 7.7738(7) Å, c = 6.2847(5) Å) adopt the crystal structure of chromiumvanadate CrVO 4 ( Cmcm , Z = 4). The resul…
Abstract The mechanical properties of polymeric materials are of considerable importance to their engineering applications. Apart from the chemical structure and the thermal history, molecular orientation has a major influence on the mechanical properties of a polymer. The increased need for more detailed data and a b…
The preparation, X-ray crystal structures, conductivity and optical properties of the salts, [ttf]3[W6O19]1, [ttf]3[Mo6O19]2(ttf = tetrathiafulvalene) and [tmtsf]3[W6O19]·2dmf 3(tmtsf = tetramethyltetraselenafulvalene) are reported. Crystal data: 1, triclinic, space group P, a= 9.965(3), b= 10.503(3), c= 10.634(3)Å, α…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCoordination of 4,7-bis(2-hydroxybenzyl)-1-oxa-4,7-diazacyclononane (LH2) with manganese(II) and -(III) and zinc(II). Crystal structure of [(LH)2Zn2(.mu.-OH)](PF6).cntdot.0.5CH3OHClaus Flassbeck, Karl Wieghardt, Eckhard Bill, Christian Butzlaff, Alfred X. Trautwein, Bernhard…
FTIR spectra are reported of methanol adsorbed at 295 K on ZnO/SiO2, on reduced Cu/ZnO/SiO2 and on Cu/ZnO/SiO2 which had been preoxidised by exposure to nitrous oxide. Methanol on ZnO/SiO2 gave methoxy species on ZnO and SiO, in addition to both strongly and weakly physisorbed methanol on SiO2. The corresponding adsor…
We provide evidence for the existence of p → p-like transitions at the silicon L2,3-edges of common silicates. This arises due to the local, tetrahedral potential at the silicon site imposed by the nearest neighbour atoms leading to a loss of inversion symmetry. In order to successfully describe the resultant electron…
Indane-1,2,3-trione 1 is conveniently prepared in quantitative yield by the azeotropic drying of ninhydrin 2 using chlorobenzene as solvent. The central CO group of the trione is extremely electrophilic and ene addition occurs at this site with a wide range of alkenes and with terminal alkynes in aprotic solvents at m…
An autoinhibitor produced by Skeletonema costatum was extracted with ethyl acetate from the cultured medium. The extract dissolved in diluted aqueous NaOH was gel-filtered on Sephadex G-15 with water. The fractions which inhibited the growth of S. costatum were extracted with ethyl acetate, and the extracts were separ…
A model for predicting Al interconnect and intermetallic contact/via electromigration time-to-failure under arbitrary current waveform is incorporated in a circuit electromigration reliability simulator. The simulator can (1) generate layout advisory for width and length of each interconnect, and the number of contact…
Abstract Solid‐state 2 H quadrupole echo nuclear magnetic resonance (NMR) spectra and measurements of 2 H spin lattice relaxation times have been obtained for films of poly( p ‐phenylene vinylene) deuterated in phenylene ring positions (PPV‐d 4 ). NMR line shapes show that all the phenylene rings of PPV undergo 180° r…
Studies on the anode efficiency of magnesium and its alloys in battery electrolytes such as magnesium perchlorate, magnesium bromide, and magnesium chloride solutions were made by galvanostatic polarisation and corrosion rate measurements. The open circuit potential and corrosion rate of magnesium increase when lead i…
Zeolite molecular sieves catalyse the cleavage of carbon–carbon double bonds of various alkenes in the presence of aqueous hydrogen peroxide as an oxidant; titanium silicate molecular sieves, TS-1 and TS-2 exhibit very high activity in the conversion of α-methylstyene into acetophenone.
A series of enthalpy relaxation measurements were carried out for the pure polymers polystyrene (PS) and poly(oxy-2,6-dimethyl-1,4-phenylene) (PPE) and for homogeneous blends thereof. The data were analyzed using Moynihan's four-parameter approach.4 For the pure components the best fit parameter values for the simple…
Preparation of chemically homogeneous cordierite powders of submicrometer size was investigated using alkoxide precursors, synthesized from Mg metal, Al(OBu s ) 3 , and partially prehydrolyzed Si(OEt) 4 . The amount of partial prehydrolysis water in precursor synthesis was changed to study the effects on the hydrolysi…
The crystallography of B2→7R stress-induced martensitic transformation in a Ni-37.0 at%Al alloy was studied using single crystals. The experimental results were compared with predictions of the phenomenological crystallographic theory. The simultaneously measured habit planes and the orientation relationship between p…
Time-resolved powder neutron diffraction has been used to study, in situ, the structural transformations and changes in the hydrogen-atom content of four ion-exchanged (Ca, K, Mg and Na) vermiculites and two natural (Ca and Na) montmorillonites undergoing dehydration. The loss of interlayer water is shown to occur in…
X-Ray absorption near-edge structure and extended X-ray absorption fine structure spectroscopies have been used to characterize iron basket-handle porphyrins in various co-ordinations, stereochemistries and oxidation states. Attention is paid to the square-planar iron(II) complexes, a dioxygen adduct of FeII and a hyd…
Thin films of tin‐doped (ITO for indium tin oxide) with different tin contents produced by a powder pyrolysis technique have been investigated by x‐ray absorption spectroscopy and x‐ray diffraction. In a previous paper, an extended x‐ray absorption fine structure (EXAFS) study at the indium K‐edge and diffraction meas…
Escherichia coli purB encodes adenylosuccinate lyase (ASL), the enzyme that catalyzes step 8 in the pathway for de novo synthesis of IMP and also the final reaction in the two-step sequence from IMP to AMP. Gene purB was cloned and found to encode an ASL protein of 435 amino acids having a calculated molecular weight…