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151.
Toner AJ Donnadieu B Sabo-Etienne S Chaudret B Sava X Mathey F Le Floch P 《Inorganic chemistry》2001,40(13):3034-3038
The bis(dihydrogen) complex RuH(2)(H(2))(2)(PCy(3))(2) (1) reacts with 2-phenyl-3,4-dimethylphosphaferrocene (L(1)) to give RuH(2)(H(2))(PCy(3))(2)(L(1)) (2). This dihydride-dihydrogen complex has been characterized by X-ray crystallography and variable-temperature (1)H and (31)P NMR spectroscopy. The exchange between the dihydrogen ligand and the two hydrides is characterized by a DeltaG() of 46.2 kJ/mol at 263 K. H/D exchange is readily observed when heating a C(7)D(8) solution of 2 (J(H-D) = 30 Hz). The H(2) ligand in 2 can be displaced by ethylene or carbon monoxide leading to the corresponding ethylene or carbonyl complexes. The reaction of 1 with 2 equiv of 3,4-dimethylphosphaferrocene (L(2)) yields the dihydride complex RuH(2)(PCy(3))(2)(L(2))(2) (5). 相似文献
152.
Addition compounds of anhydrous mercury(II) halides were prepared with propylamine, isopropylamine, butylamine and isobutylamine. These solyates have the general formula HgX2, 2RNH2. A study of their thermal stability by TG and DTA methods has shown that some stable intermediates are produced in the course of decomposition. The standard enthalpies of formation have been determined by dissolution in acidic medium and the variation of enthalpy based on the evolution of the molecules of amine was determined by this way and by means of a differential enthalpic analyser. The interpretation of their infrared spectra is discussed. 相似文献
153.
Iodine and bromine in the presence of sodium benzenesulphinate react with olefins in acetone solution to give halosulphones resulting from an apparent steric direction of attack at the intermediate halonium ion. A straightforward preparation of benzenesulphonyl iodide from benzenesulphonyl chloride and sodium iodide is also described. 相似文献
154.
Samuel C. Perry Pui-ki Leung Ling Wang Carlos Ponce de León 《Current Opinion in Electrochemistry》2020
CO2 reduction processes continue to be developed for electrosynthesis, energy storage applications, and environmental remediation. A number of promising materials have shown high activity and selectivity to target reduction products. However, the progress has been mainly at a small laboratory scale, and the technical challenges of large scale CO2 reduction have not been considered adequately. This review covers recent advancements in catalyst materials and cell designs. The leading materials for CO2 reduction to a number of useful products are presented with their corresponding cell and reactor designs. The latest efforts to progress to industrially relevant scales are discussed, along with the challenges that must be met for carbon dioxide reduction to be a viable route for mass scale production. 相似文献
155.
Entrapment and release of sodium polystyrene sulfonate (SPS) from calcium alginate gel beads 总被引:3,自引:0,他引:3
I. Rousseau D. Le Cerf L. Picton J.F. Argillier G. Muller 《European Polymer Journal》2004,40(12):2709-2715
The release of sodium polystyrene sulfonate (SPS) from calcium alginate hydrogel beads has been studied. It has been shown that the structure of the cross-linked calcium alginate network is of primary importance in the retention and/or release of the SPS. This has been evidenced by studying the influence of Ca2+ concentration, molar masses (Mn) and the ratio of mannuronic acid/guluronic acid components. A minimum in the SPS release is observed in relation with the organization of the network structure. Conditions inducing the organization of a strong gel (e.g. high Ca2+ concentration for example) are not always related to a low release. A good control of release is found when a compromise between a well-structured hydrogel and sterical consideration of SPS is reached. 相似文献
156.
157.
C. Le Van 《Journal of Optimization Theory and Applications》1980,30(1):33-44
We define the degree of a family of convex functionsf
x, wherex
, and prove that, if this degree is different from zero, one has at least one Nash equilibrium point in . This is a criterion of localization of such equilibrium points. 相似文献
158.
S. Della Negra H. Gauvin H. Jungclas Y. Le Beyec M. Lefort 《Zeitschrift für Physik A Hadrons and Nuclei》1977,282(1):65-73
Excitation functions have been drawn for evaporation residues issued from150Gd, a compound nucleus produced either by16O ions on134Ba, or by40Ar on110Pd. Absolute cross sections were measured for145–147Gd,145–147Eu,141m Sm,143m Sm,140m Pm and139m Nd. Complete fusion cross sections have been obtained and compared to calculated estimations based, at low energies, on the simple expressionσ CF=πR Fuss 2 (1?V Fus/E) whereR Fus andV Fus are respectively the distance and the potential for fusion atdV/dr=0. For high energies σCF=πR cr 2 (1?Vcr/E) with the model of critical distanceR cr and critical potentialV cr. Thresholds energies have been determined with a particular care. The analysis of the shape and the width of excitation functions, particularly for the emission of 4 and 5 neutrons, has been carried out and compared to calculated values. The difference between argon and oxygen induced reactions has been attributed to the difference inl population in the entrance channel. 相似文献
159.
Fipronil, a phenylpyrazole insecticide introduced for pest control on a broad range of crops, can also affect non-target insects such as honeybees. More widely, non-target environment such as milk produced by dairy cows fed with maize silage from treated seeds (=silage T) can be affected. To assess the potential transfer of fipronil residues (sulfone, sulfide, fipronil, desulfinyl and amide), a methodology including gas chromatography coupled with tandem mass spectrometry (GC-MS/MS) analysis was developed and validated according to the 2002/657/EC decision, in order to reach a level of quantification below 0.1 μg L−1 in milk and 0.1 μg kg−1 in plants. Twelve dairy cows were fed with silage T during 4 months. Concentration of fipronil in treated seeds was estimated at 1 g kg−1, whereas silage from these seeds contained 0.30 ± 0.05 μg kg−1 of dry material of fipronil, 0.13 ± 0.03 μg kg−1 of dry material of sulfone. Sulfide residues were below the limit of quantification. Silage from untreated seeds (=silage U) presented traces of fipronil and sulfone, respectively at 0.04 ± 0.06 and 0.02 ± 0.03 μg kg−1 of dry material. Contribution of fipronil residues from supplies was insignificant. During administration of silage T, only sulfone residues were quantified in milk. The average concentration was 0.14 ± 0.05 μg L−1. Before and after administration, sulfone residues were detected but not quantifiable (<0.025 μg L−1). Our results suggest a transfer of fipronil from feed to milk under its sulfone form. Moreover, traces of fipronil residues in maize U, soya, wheat and straw show a diffuse contamination of this pesticide in the environment. 相似文献
160.
Separation techniques coupled to inductively coupled plasma mass spectrometry (ICP-MS) is reviewed. ICP-MS technique is described briefly. Coupling of the different separation techniques are described, together with the most common applications used for each technique that has been described in the literature. An overview for the future of separation techniques coupled to ICP-MS with regard to elemental speciation is discussed. 相似文献