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排序方式: 共有1227条查询结果,搜索用时 15 毫秒
991.
992.
Dr. Marcello Gennari Deborah Brazzolotto Shengying Yu Dr. Jacques Pécaut Dr. Christian Philouze Mathieu Rouzières Dr. Rodolphe Clérac Dr. Maylis Orio Dr. Carole Duboc 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(51):18770-18778
It has recently been proposed that disulfide/thiolate interconversion supported by transition‐metal ions is involved in several relevant biological processes. In this context, the present contribution represents a unique investigation of the effect of the coordinated metal (M) on the Mn+?disulfide/M(n+1)+?thiolate switch properties. Like its isostructural CoII‐based parent compound, CoII 2 SS (Angew. Chem. Int. Ed. 2014 , 53, 5318), the new dinuclear disulfide‐bridged MnII complex MnII 2 SS can undergo an MII?disulfide/MIII?thiolate interconversion, which leads to the first disulfide/thiolate switch based on Mn. The coordination of iodide to the metal ion stabilizes the oxidized form, as the disulfide is reduced to the thiolate. The reverse process, which involves the reduction of MIII to MII with the concomitant oxidation of the thiolates, requires the release of iodide. The MnII 2 SS complex slowly reacts with Bu4NI in CH2Cl2 to afford the mononuclear MnIII?thiolate complex MnIIII . The process is much slower (ca. 16 h) and much less efficient (ca. 30 % yield) with respect to the instantaneous and quantitative conversion of CoII 2 SS into CoIIII under similar conditions. This distinctive behavior can be rationalized by considering the different electrochemical properties of the involved Co and Mn complexes and the DFT‐calculated driving force of the disulfide/thiolate conversion. For both Mn and Co systems, MII?disulfide/MIII?thiolate interconversion is reversible. However, when the iodide is removed with Ag+, the MII 2 SS complexes are regenerated, albeit much slower for Mn than for Co systems. 相似文献
993.
Guillot P Panizza P Salmon JB Joanicot M Colin A Bruneau CH Colin T 《Langmuir : the ACS journal of surfaces and colloids》2006,22(14):6438-6445
In this work, a viscosimeter implemented on a microfluidic chip is presented. The physical principle of this system is to use laminar parallel flows in a microfluidic channel. The fluid to be studied flows side by side with a reference fluid of known viscosity. By using optical microscopy, the shape of the interface between both fluids can be determined. Knowing the flow rates of the two liquids and the geometrical features of the channel, the mean shear rate sustained by the fluid and its viscosity can thus be computed. Accurate and precise measurements of the viscosity as a function of the shear rate can be made using less than 300 microL of fluid. Several complex fluids are tested with viscosities ranging from 10(-)(3) to 70 Pa.s. 相似文献
994.
Eric Gendron Franois Assmat Franois Hammer Pascal Jagourel Fanny Chemla Philippe Laporte Mathieu Puech Michel Marteaud Frdric Zamkotsian Arnaud Liotard Jean-Marc Conan Thierry Fusco Norbert Hubin 《Comptes Rendus Physique》2005,6(10):1110-1117
FALCON is a wide-field, multi-object integral field spectrograph equipped with adaptive optics. It is dedicated to the study of the formation process of primordial galaxies. The AO system uses natural guide stars, and the high sky coverage required for these studies is obtained using tomographic techniques for the wavefront analysis. The structure of the OA system is very new, and particularly suited for a future implementation on extremely large telescopes. To cite this article: E. Gendron et al., C. R. Physique 6 (2005). 相似文献
995.
In this article we study how a subshift can simulate another one, where the notion of simulation is given by operations on subshifts inspired by the dynamical systems theory (factor, projective subaction …). There exists a correspondence between the notion of simulation and the set of forbidden patterns. The main result of this paper states that any effective subshift of dimension d—that is a subshift whose set of forbidden patterns can be generated by a Turing machine—can be obtained by applying dynamical operations on a subshift of finite type of dimension d+1—a subshift that can be defined by a finite set of forbidden patterns. This result improves Hochman’s (Invent. Math. 176(1):131–167, 2009). 相似文献
996.
Mathieu Francoeur M. Pinar Mengüç Rodolphe Vaillon 《Applied Physics A: Materials Science & Processing》2011,103(3):547-550
The possibility of controlling near-field radiative heat transfer with the use of silicon carbide thin films supporting surface
phonon–polaritons in the infrared spectrum is explored. For this purpose, the local density of electromagnetic states is calculated
and analyzed within the nanometric gap formed between two SiC films as well as the radiative heat flux exchanged between the
thin layers. 相似文献
997.
The present work addresses the question of the range and amplitude of bridging attraction that is induced between surfactant micelles functionalized with complexing groups in the presence of coordination centers. An alkylethoxylated ester phosphate (AEP) is synthesized from a non‐ionic surfactant and anchored into DTAB micelles. In the absence of any coordination center, functionalized micelles repel each other. Phase behavior, dynamic light scattering and small angle neutrons scattering (SANS) experiments show that this repulsive interaction is switched to attractive by the addition of coordination centers such as aluminum cations. The extent of the composition range of coexisting phase depends on the concentration of coordination center and on the pH. Analysis of the structure factor obtained from SANS shows that the range of attraction is determined by the molecular dimension of the chelating surfactant, while the depth can be tuned with the concentration of coordination center and the pH. The strong influence of the pH is interpreted as arising from the condensation of aluminium cations that lead to high functional polynuclear complexes. 相似文献
998.
The simulation of the thermal behavior of energetic materials based on DSC and HFC signals 总被引:3,自引:0,他引:3
B. Roduit L. Xia P. Folly B. Berger J. Mathieu A. Sarbach H. Andres M. Ramin B. Vogelsanger D. Spitzer H. Moulard D. Dilhan 《Journal of Thermal Analysis and Calorimetry》2008,93(1):143-152
Two small calibre and four medium calibre types of propellants were investigated non-isothermally (0.25–4K min−1) by differential scanning calorimetry (DSC) in the range of RT-260°C and isothermally (60–100°C) by heat flow calorimetry
(HFC). The data obtained from both techniques were used for the calculation and comparison of the kinetic parameters of the
decomposition process. The application of HFC allowed to determine the kinetic parameters of the very early stage of the reaction
(reaction progress α below 0.02) what, in turn, made possible the precise prediction of the reaction progress under temperature
mode corresponding to real atmospheric changes according to STANAG 2895. In addition, the kinetic parameters obtained from
DSC data enabled determination of self-accelerating decomposition temperature (SADT) and comparison of the predicted ignition
temperature during slow cook-off with the experimental results. The study contains also the results of the calculation of
the time to maximum rate (TMRad) of the propellants under adiabatic conditions. 相似文献
999.
All \(\sigma \)-compact, locally compact groups acting sharply \(n\)-transitively and continuously on compact spaces \(M\) have been classified, except for \(n=2,3\) when \(M\) is infinite and disconnected. We show that no such actions exist for \(n=2\) and that these actions for \(n=3\) coincide with the action of a hyperbolic group on a space equivariantly homeomorphic to its hyperbolic boundary. We further characterize non-compact groups acting 3-properly and transitively on infinite compact sets as non-elementary boundary-transitive hyperbolic groups, which in turn were recently studied by Caprace, de Cornulier, Monod and Tessera. As an important tool, we generalize Bowditch’s topological characterization of discrete hyperbolic groups to locally compact hyperbolic groups. Finally, we show that if a locally compact group acts continuously, 4-properly and 4-cocompactly on a locally connected metrizable compactum M, then M has a global cut point, which is in sharp contrast to the \(3\)-proper, \(3\)-cocompact case due to the solution of Bowditch’s cut-point conjecture. 相似文献