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991.
Murielle Rivenet Pascal Roussel Francis Abraham 《Journal of solid state chemistry》2008,181(10):2586-2590
Single crystals of Bi(C2O4)OH were obtained by the slow diffusion of Bi3+ cations through silica gel impregnated with oxalic acid. The structure was solved in the Pnma space group with a=6.0853(2) Å, b=11.4479(3) Å, c=5.9722(2) Å, leading to R=0.0188 and wR=0.0190 from 513 unique reflections. The bismuth coordination polyhedron is a BiO6E pentagonal bipyramid with the lone pair E sitting at an axial vertex. The opposite axial vertex is occupied by a hydroxyl oxygen atom, which is also an equatorial corner of a neighboring BiO6E bipyramid. The sharing of the hydroxyl oxygen atoms build zig-zag chains running down the [100] direction. These chains are aligned in a sheet parallel to the (010) plane and are further connected through oxalate ions to form a three-dimensional arrangement. On heating, Bi(C2O4)OH decomposes to the meta-stable quadratic β-Bi2O3 phase. 相似文献
992.
Nanocomposites based on chloroprene rubber: Effect of chemical nature and organic modification of nanoclay on the vulcanizate properties 总被引:2,自引:0,他引:2
Amit Das Francis Reny Costa Udo Wagenknecht Gert Heinrich 《European Polymer Journal》2008,44(11):3456-3465
The effect of two chemically opposite type of nanofillers, namely montmorillonite (MMT) and layered double hydroxide (LDH), both in pristine and organically modified forms (OLDH and OMMT) on the mechanical properties and crystallization behavior of chloroprene rubber (CR) vulcanizates have been investigated. While the addition of very small amount of pristine clays shows a significant improvement of the physical properties of the CR based nanocomposites, the organic modification improves the reinforcing efficiency of MMT more than that of LDH. MMT is found to enhance the crystallization tendency of CR chains, whereas LDH has a role to resist it as observed from the dynamic mechanical analysis (DMA). The DMA results also show that the presence small amount of nanoclay enhances the storage modulus of CR based vulcanizates, which becomes more pronounced in case of organically modified clays, especially with OMMT. Finally, we report the ‘house of cards’ structure of exfoliated platelets of montmorillonite in the CR matrix which are produced by mechanical shear mixing. 相似文献
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Back Cover: Engaging Copper(III) Corrole as an Electron Acceptor: Photoinduced Charge Separation in Zinc Porphyrin–Copper Corrole Donor–Acceptor Conjugates (Chem. Eur. J. 4/2016) 下载免费PDF全文
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D. C. Francis 《International Journal of Mathematical Education in Science & Technology》2013,44(3):263-268
This paper formed part of a research project carried out by the author into the mathematical education of engineers.1 In this part of the work an attempt was made to assess the relative importance of various aspects of ordinary differential equations in the teaching of engineering students and to find out which types of equations were used in the various engineering disciplines. A questionnaire was circulated and the replies were collated to give the results. 相似文献