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891.
Andreas Tengå Sven Lidin Prof. Jean‐Philippe Belieres Prof. Nathan Newman Prof. Yang Wu Ulrich Häussermann Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(27):6704-6710
Although free from structural disorder , the new intermetallic compound Cd13?xInySb10 (see figure) displays similarly low thermal conductivity values as disordered thermoelectric β‐Zn4Sb3 with an isostructural framework.
892.
Robert D. Shannon Olaf Medenbach Philippe Ghosez 《Journal of solid state chemistry》2009,182(10):2762-2768
The refractive indices of ZrW2O8, measured at wavelengths of 435.8-643.8 nm, were used to calculate nD at λ=589.3 nm and n∞ at λ=∞ from a one-term Sellmeier equation. Refractive indices, nD and dispersion values, A, are, respectively, 1.8794 and 114×10−16 m2. The high dispersion, relative to other molybdates, tungstates and Zr-containing compounds, is attributed to the low value of Eo=7.7 eV and mean cation coordination number. Total electronic polarizabilities, αtotal, were calculated from n∞ and the Lorenz-Lorentz equation. The unusually large difference between the observed polarizability of 20.087 Å3 and the calculated total polarizability αT of 17.59 Å3 (Δ=+12.4%) is attributed to (1) a large M-O-W angle, (2) a high degree of W 5d-O(terminal) 2p and Zr nd-O 2p hybridization, and (3) unusually high oxygen displacement factors, B(O), normalized to B(W). 相似文献
893.
894.
New metallocene dichlorides [η5-(1,4-Me2-2,3-Ph2-C5H)2TiCl2] (2), [η5-(1,4-Me2-2,3-Ph2-C5H)2ZrCl2] (3) and [η5-(1,4-Me2-2,3-Ph2-C5H)η5-(C5H5)ZrCl2] (4) were prepared from lithium salt of 1,4-dimethyl-2,3-diphenylcyclopentadiene (1) and [TiCl3(THF)3], [ZrCl4] and [η5-(C5H5)ZrCl3(DME)], respectively. Compounds 2-4 were characterized by NMR spectroscopy, EI-MS and IR spectroscopy, and the solid state structure of 3 was determined by single crystal X-ray crystallography. The catalytic systems 3/MAO and 4/MAO were almost inactive in polymerization of ethylene at 30-50 °C, however, they exhibited high activity at temperature 80 °C. The catalyst formed from 2 and excess of MAO was practically inactive at all temperatures. 相似文献
895.
Yahia Lemmouchi Marius Murariu Allan J. Amass Philippe Dubois 《European Polymer Journal》2009,45(10):2839-2848
Polylactide (PLA) is a potential candidate for the partial replacement of petrochemical polymers because it is biodegradable and produced from annually renewable resources. Characterized by its high tensile strength, unfortunately the brittleness and rigidity limit its applicability. For a great number of applications such as packaging, fibers, films, etc., it is of high interest to formulate new PLA grades with improved flexibility and better impact properties.In order to develop PLA-based biodegradable packaging, the physico-mechanical properties of commercially available PLA should be modified using biodegradable plasticizers. To this end, PLA was melt-mixed with blends of tributyl citrate and more thermally stable low molecular weight block copolymers based on poly(d,l-lactide) and poly(ethylene glycol) of different molecular weights and topologies. The copolymers have been synthesized using a potassium based catalyst which is expected to be non toxic and were characterized by utilization of TGA, GPC and NMR techniques.The effect of the addition of up to 25 wt% plasticizer on the thermo-mechanical properties of PLA was investigated and the results were correlated with particular attention to the relationship between properties and applications.To confirm the safety of the catalyst used for the preparation of the copolymers, in vitro cytotoxicity tests have been carried out using MTS assay and the results show their biocompatibility in the presence of the fibroblast cells.Compost biodegradation experiments carried out using neat and plasticized PLA have shown that the presence of plasticizers accelerates the degradation of the PLA matrix. 相似文献
896.
The synthesis and crystal structure of the novel reduced molybdenum oxide Mg4.5Pr79.5Mo126O312 are presented. This compound crystallizes in the trigonal space group R-3 m with a = 11.3061(2) Å, c = 58.242(1) Å, V = 6447.5(2) Å3, and Z = 1. Refinements yield R(F 2) = 0.0433 and wR(F 2) = 0.0931 for 2827 unique reflections. The structure is built up from alternating slabs made up of molybdenum forming Mo3, Mo7 and Mo19 clusters, praseodymium and oxygen atoms, and slabs containing isolated MoO6 octahedra. The Pr3+ cations are localized either within the slabs or at their borderlines to ensure the cohesion between the slabs. Of the six crystallographically independent sites occupy by the Pr3+ cations, two of them also contain randomly about 15% and 20% of Mg2+ cations while the remaining four are fully occupied by the Pr3+ cations. 相似文献
897.
Valérie Baco-Carles Isabelle Pasquet Véronique Laurent Armand Gabriel Philippe Tailhades 《Solid State Sciences》2009,11(8):1503-1506
Dense micro-cermets made of nickel ferrites and copper micrometric particles were obtained from partial reduction under hydrogenated atmosphere at 350 °C of mixed copper nickel ferrites, and sintering in nitrogen at 980 °C. The small copper particles are homogeneous in size and well dispersed in the spinel oxide matrix. No exudation of copper metal was observed after sintering. The micro-cermets prepared are semi-conducting materials with electrical conductivity lying from 44 to 130 S/cm at 980 °C. Their overall characteristics make them interesting for inert anodes dedicated to aluminium electrolysis in melted cryolite. 相似文献
898.
Chun-Ze Lai Marti M. Joyer Melissa A. Fierke Nicholas D. Petkovich Andreas Stein Philippe Bühlmann 《Journal of Solid State Electrochemistry》2009,13(1):123-128
Solid-contact ion-selective electrodes (SC-ISEs) can exhibit very low detection limits and, in contrast to conventional ISEs,
do not require an optimization of the inner filling solution. This work shows that subnanomolar detection limits can also
be achieved with SC-ISEs with three-dimensionally ordered macroporous (3DOM) carbon contacts, which have been shown recently
to exhibit excellent long-term stabilities and good resistance to the interferences from oxygen and light. The detection limit
of 3DOM carbon-contacted electrodes with plasticized poly-(vinyl chloride) as membrane matrix can be improved with a high
polymer content of the sensing membrane, a large ratio of ionophore and ionic sites, and conditioning with a low concentration
of analyte ions. This permits detection limits as low as 1.6 × 10−7 M for K+ and 4.0 × 10−11 M for Ag+. 相似文献
899.
Wei Wu Prof. Junjing Gu Jinshuai Song Sason Shaik Prof. Philippe C. Hiberty Prof. 《Angewandte Chemie (International ed. in English)》2009,48(8):1407-1410
Bonded or not bonded? An ab initio valence bond study of [1.1.1]propellane shows that the two bridgehead carbons are linked by a strong and direct σ bond that is neither classically covalent nor classically ionic, but rather a charge‐shift bond, in which the covalent–ionic resonance energy plays the major role. As such, the central bond of [1.1.1]propellane closely resembles the single bond of difluorine.
900.
Anna Giusti Dr. Gaëlle Charron Dr. Sandra Mazerat Jean‐Daniel Compain Pierre Mialane Prof. Anne Dolbecq Dr. Eric Rivière Dr. Wolfgang Wernsdorfer Dr. Rosa Ngo Biboum Bineta Keita Dr. Louis Nadjo Prof. Arianna Filoramo Dr. Jean‐Philippe Bourgoin Dr. Talal Mallah Prof. 《Angewandte Chemie (International ed. in English)》2009,48(27):4949-4952
A POM to remember : Hexanuclear FeIII polyoxometalate (POM) single‐molecule magnets (see structure) can be noncovalently assembled on the surface of single‐wall carbon nanotubes. Complementary characterization techniques (see TEM image and magnetic hysteresis loops) demonstrate the integrity and bistability of the individual molecules, which could be used to construct single‐molecule memory devices.