Materials Literature
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An expression for the Einstein coefficient of spontaneous emission related to the pseudo-multipolar field, originally proposed by Jørgensen and Judd to account for hypersensitivity, is derived from the crystal field expansion due to point dipoles localized at the ligands. The expression is then successfully applied to…
Abstract The structures of Li 2 SiO 3 [ Cmc 21, a = 9.396(1), b = 5.396(1), c = 4.661(1) Å] and Li 2 GeO 3 [ Cmc 2 1 , a = 9.634(2), b = 5.481(2), c = 4.843(1) Å] have been refined to R values of 0.022 and 0.016 respectively. The distances within the tetrahedral chains were found to be: Si−O = 1.677(2), Ge−O = 1.811(3…
Abstract Films of low‐density polyethylene, polypropylene, and rigid poly(vinyl chloride) were exposed for 1700 h to artificial aging in a Weather‐O‐Meter. Photochemical aging was characterized by tensile measurements. We noted that only ultimate properties are affected, whereas properties defined in the low strain ra…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSilicon photocathode behavior in acidic vanadium(II)-vanadium(III) solutionsA. Heller, H. J. Lewerenz, and B. MillerCite this: J. Am. Chem. Soc. 1981, 103, 1, 200–201Publication Date (Print):January 1, 1981Publication History Published online1 May 2002Published inissue 1 Jan…
Solution photolysis of hexakis(isopropylammonium) heptamolybdate(VI) trihydrate, [NH3Pri]6[Mo7O24]·3H2O (1), at pH 5.4 leads to reduction to MoV with involvement of hydroxy-radicals, followed by decomposition to yellow and blue species. Propylene and acetone were detected as oxidation products but quantum yields for t…
Irradiation of tris(2,2′-bipyridyl)ruthenium(II) in aqueous solution containing a sacrificial electron acceptor results in formation of bipy3Ru3+, a powerful oxidant which is able, in the presence of a redox catalyst, to oxidise water to O2. Both colloidal RuO2 and simple cobalt(II) ions are effective catalysts for O2…
Black needles of Lix[Pt(S2C4N2)2].2H2O (x ca. 0.75) exhibit a room temperature conductivity of 30–200 Ω–1 cm–1 and a temperature dependence of the conductivity similar to that of the one-dimensional metallic tetracyanoplatinate complexes such as K2[Pt(CN)4]Br0·3.3H2O.
The reaction of[Au9(PPh3)8][NO3]3with KI in acetone yields [Au4(µ-I)2(PPh3)4] which has been shown by X-ray crystallography to contain a tetrahedral gold cluster connected to four terminal triphenylphosphine groups and two edge-bridging iodine ligands; the latter bonding mode is novel for gold clusters.
Conference International Symposium on Polyvinylchloride, Third, Cleveland, Ohio, USA, 1980-08-10–1980-08-15 Published Online: 2009-01-01 Published in Print: 1981-01-01 © 2013 Walter de Gruyter GmbH, Berlin/Boston
The infrared spectrum (700–4000 cm–1) of quasi-stoichiometric microcrystalline ZnO has been recorded at various temperatures (97–523 K) and following various redox treatments.A broad band centred at ca. 1500 cm–1, produced on samples cooled down to 97 K in oxygen, is ascribed to the increasing concentration of un-ioni…
A short review is given of successively the diamagnetic susceptibility, the refractive index, the dielectric permittivity, the elastic constants and the viscosity coefficients of nematic liquid crystals. Emphasis is on typical results that have been obtained, and the possibilities and problems connected with a molecul…
Silver nitrate 3 mug/ml prevented the separation into two daughter cells of sensitive dividing cells of Pseudomonas aeruginosa growing in nutrient broth plus the chemical. Cell size of sensitive cells was increased and the cytoplasmic contents, cytoplasmic membrane and external cell envelope structures were all abnorm…
Three paramagnetic Fe defect complexes have been observed by electron-spin resonance in chemically reduced crystals of SrTi${\mathrm{O}}_{3}$. These are identified as (1) an ${\mathrm{Fe}}^{3+}$ ion substituted on a Ti site with a nearby charge-compensating interstitial impurity, and (2) and (3) two charge states of s…
Abstract Progress in designing and constructing an atmospheric or environmental scanning electron microscope (SEM) is reported. The introduction of vacuum pumping between the objective and pressure limiting aperture has allowed the use of relatively large pressure limiting apertures, i.e., up to 57 μm for operation at…
Abstract River inputs of dissolved silica into a shallow eutrophic lake (Lough Neagh, N Ireland) are quantified. Exports of silica are high (3.6 to 9.6 tonnes dissolved SiO 2 km −2 y −1 ), but the spring concentration of dissolved silica in the lake depends on release of silica from the sediments. Two planktonic diato…
Fluorescence quantum yields and excited singlet-state lifetimes were measured for a series of substituted tetraphenylporphyrins in benzene solution. The rate constants for non-radiative deactivation of the excited singlet state correlated with the Hammett constant of the substituent for both electron withdrawing and e…
A separation-method for dispersed carbonaceous material in rocks and a calculation-method for Lc(002) are presented, and a numerical expression of the graphitizing-degree is newly proposed revising Tagiri and Tsuboi (1979), Graphitizing-degree=[(d002-3.70)/log (Lc(002)/1000)]×100. Some examples in the metamorphic aure…
Some electrooptic and thermooptic effects of cholesteric phase are used in liquid crystal visualisation and display systems provided spiral pitch is equal to a visible wavelength or several micrometers. Liquid crystals with cholesteric properties were generally cholesteric esters. Unfortunately these materials are che…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStudies of the mechanism and kinetics of plasma-initiated polymerization of methyl methacrylateD. R. Johnson, Y. Osada, A. T. Bell, and M. ShenCite this: Macromolecules 1981, 14, 1, 118–124Publication Date (Print):January 1, 1981Publication History Published online1 May 2002…
Carbon dioxide sorption isotherms in poly(methyl methacrylate) (PMMA) and poly(ethyl methacrylate) (PEMA) are reported for pressures up to 20 atm. Temperatures between 35 and 80°C were studied for PMMA and temperatures between 30 and 55°C were studied for PEMA. Typical dual mode sorption isotherms concave to the press…