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21.
Sylvie Condon Chunhai Zou Jean-Yves Nédélec 《Journal of organometallic chemistry》2006,691(15):3245-3250
Reduction of decyl dichloro- and trichloroacetate, under mild electrolysis conditions by using the sacrificial anode process, affords α-chlorocarbanions which readily react with trialkylboranes to give alkylated products in a one step reaction. 相似文献
22.
Heyrman M Chatillon C Collas H Chemin JL 《Rapid communications in mass spectrometry : RCM》2004,18(2):163-174
The thermodynamic properties of condensed phases, i.e. the activities of components, can be determined from partial pressures measured by the Knudsen cell mass spectrometric method. Improvements in accuracy and yield of this method are obtained with the use of twin cells, an idea proposed in the 1960s. The multiple cell method was perfected in 1977 in our laboratory. Changes to molecular beam sampling and furnace assemblies were required to make the multiple Knudsen cell technique work properly. This paper summarizes these prerequisites, and presents a new device and the associated method of measurements, as well as the necessary tests performed with a silver sample in each cell. 相似文献
23.
Boutreau L Léon E Salpin JY Amekraz B Moulin C Tortajada J 《European journal of mass spectrometry (Chichester, England)》2003,9(4):377-390
The analytical distinction of the most common isomeric underivatized hexoses was investigated by means of mass spectrometry experiments. Electrospray ionization and tandem mass spectrometry were used in the analysis of silver and copper-coordinated monosaccharides (D-glucose, D-galactose, D-fructose, O-methyl-alpha-D-glucose and O-methyl-beta-D-glucose). The results show that cationization by Ag(+) allows the differentiation of the three first monosaccharides while the complexes formed by association of Cu(+) with these three monosacharides display a similar reactivity that prevents stereoisomer distinction. Unlike copper, silver adduct-ions of both alpha and beta anomeric O-methyl-D-glucoses exhibit specific decomposition patterns (i.e. a loss of methanol for the alpha-anomer and a loss of silver hydride for the beta-anomer), which allow an easy characterization. A theoretical survey of selected complexes, based on the use of DFT calculations were carried out on both anomers in order to rationalize the experimental findings. 相似文献
24.
The electroreduction of a mixture of SO2 and CF3Br in DMF, in an undivided cell with a soluble anode (Mg or Zn) lead to salt of trifluoromethane sulfinic acid in high yield. 相似文献
25.
Alain Lascoux Jean-Christophe Novelli Jean-Yves Thibon 《Journal of Algebraic Combinatorics》2013,37(4):621-642
We define new families of noncommutative symmetric functions and quasi-symmetric functions depending on two matrices of parameters, and more generally on parameters associated with paths in a binary tree. Appropriate specializations of both matrices then give back the two-vector families of Hivert, Lascoux, and Thibon and the noncommutative Macdonald functions of Bergeron and Zabrocki. 相似文献
26.
The aim of this paper is to carry out statistical inference in a competing risks setup when only selection-biased observation of the data of interest is available. We introduce estimators of the cumulative incidence functions and study their joint large sample behavior. 相似文献
27.
28.
Some of the main progress on the investigation of the mechanism of the wave formation in explosive welding at the Institute
of Mechanics is summarized and others' previous works are reviewed. Our systematic experiments and analysis do not substantiate
the theory of wave formation based on Karman vortex-street analogy or Helmholtz instability. On the contrary, they show that
material strength insensitive to strain rate plays an important role. A simple hydro-plastic model is presented to explain
the main features regarding the interfacial wave formation and to estimate the magnitude of wave length. The result is in
broad agreement with experiment. 相似文献
29.
Functionalization at C-2 and C-5 of N-benzenesulfonyl-4-azaindole 1 was performed by lithiation reactions and original palladium-catalyzed chemistry. It led to very useful new substituted 4-azaindole derivatives in fair to high yields. 相似文献
30.
Stepan Oryshchyn Volodymyr Babizhetskyy Olga Zhak Jean-Yves Pivan Arndt Simon 《Journal of solid state chemistry》2010,183(11):2534-2543
The new ternary pnictides Er12Ni30P21 and Er13Ni25As19 have been synthesized from the elements. They crystallize with hexagonal structures determined from single-crystal X-ray data for Er12Ni30P21 (space group P63/m, a=1.63900(3) nm, c=0.37573(1) nm, Z=1, RF=0.062 for 1574 F-values and 74 variable parameters), and for Er13Ni25As19 (Tm13Ni25As19-type structure, space group P6?, a=1.6208(1) nm, c=0.38847(2) nm, Z=1, RF=0.026 for 1549 F-values and 116 variable parameters). These compounds belong to a large family of hexagonal structures with a metal-metalloid ratio of 2:1. HRTEM investigations were conducted to probe for local ordering of the disordered structure at the nanoscale. The magnetic properties of the phosphide Er12Ni30P21 have been studied in the temperature of range 2<T<300 K and with applied fields up to 5 T. The magnetic susceptibility follows the Curie-Weiss law from 4 to 300 K. The measured value of μeff=9.59 μB corresponds to the theoretical value of Er3+. 相似文献