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161.
Didier Robert 《Journal of Functional Analysis》1982,45(1):74-94
Let . Under suitable conditions we prove that is a pseudodifferential operator whose symbol has an asymptotic: . More general pseudodifferential operator's classes are also considered. We apply this result to study the semi-classical behaviour of the spectrum of Hv as h → 0. So, we improve recent results obtained by J. Chazarain and by the author in collaboration with B. Helffer. Furthermore we give a precise meaning to the formal development considered in B. Grammaticos and A. Voros' work (Ann. Physics123 (1979), 359–380). 相似文献
162.
Oxidation of weakly acidic carbon compounds was achieved with air in presence of KF-Al2O3 as catalyst. A carbanion process is proposed. 相似文献
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Ardès-Guisot N Durand JO Granier M Perzyna A Coffinier Y Grandidier B Wallart X Stievenard D 《Langmuir : the ACS journal of surfaces and colloids》2005,21(21):9406-9408
Despite the importance of the isocyanate group in chemistry, very few examples of isocyanate-modified silicas have been reported, and all of the strategies described so far led to partial or total hydrolysis or condensation of the isocyanate group. By synthesizing trichlorosilane isocyanate as the coupling reagent, we show that oxidized silicon wafers are successfully modified with the isocyanate group. Our method is achieved in mild conditions, at low temperature, without side-reactions and allows the formation of a self-assembled monolayer (SAM) of isocyanates. The isocyanate group then offers a flexible way to further functionalize silica substrates with different nucleophiles, due to its high and specific reactivity. 相似文献
167.
Daniel MC Ruiz Aranzaes J Astruc D 《Chemical communications (Cambridge, England)》2005,(12):1569-1571
Commercial DSM polyamine dendrimers inhibit the observation of the cyclic voltammetry (CV) of simple ferrocenes all the more as they are larger (marked dendritic effect); the CV is re-established, however, if a OH-containing group is present in the ferrocene derivative. 相似文献
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Samuel Jorice Raccurt Olivier Poncelet Olivier Auger Aurélien Ling Wai-Li Cherns Peter Grunwald Didier Tillement Olivier 《Journal of nanoparticle research》2010,12(6):2255-2265
Journal of Nanoparticle Research - Fluorescent silica nanoparticles are widely used for various applications from mechanical reinforcement to biology. In many cases, their surface has to be... 相似文献
170.
Firley D Courcot B Gillet JM Fraisse B Zouhiri F Desmaële D d'Angelo J Ghermani NE 《The journal of physical chemistry. B》2006,110(1):537-547
We have established that polyhydroxylated styrylquinolines are potent inhibitors of HIV-1 integrase (IN). Among them, we have identified (E)-8-hydroxy-2-[2-(4,5-dihydroxy-3-methoxyphenyl)-ethenyl]-7-quinolinecarboxylic acid (1) as a promising lead. Previous molecular dynamics simulations and docking procedures have shown that the inhibitory activity involves one or two metal cations (Mg2+), which are present in the vicinity of the active center of the enzyme. However, such methods are generally based on a force-field approach and still remain not as reliable as ab initio calculations with extended basis sets on the whole system. To go further in this area, the aim of the present study was to evaluate the predictive ability of the electron density and electrostatic properties in the structure-activity relationships of this class of HIV-1 antiviral drugs. The electron properties of the two chemical progenitors of 1 were derived from both high-resolution X-ray diffraction experiments and ab initio calculations. The twinning phenomenon and solvent disorder were observed during the crystal structure determination of 1. Molecule 1 exhibits a planar s-trans conformation, and a zwitterionic form in the crystalline state is obtained. This geometry was used for ab initio calculations, which were performed to characterize the electronic properties of 1. The electron densities, electrostatic potentials, and atomic charges of 1 and its progenitors are here compared and analyzed. The experimental and theoretical deformation density bond peaks are very comparable for the two progenitors. However, the experimental electrostatic potential is strongly affected by the crystal field and cannot straightforwardly be used as a predictive index. The weak difference in the theoretical electron densities between 1 and its progenitors reveals that each component of 1 conserves its intrinsic properties, an assumption reinforced by a 13C NMR study. This is also shown through an excellent correlation of the atomic charges for the common fragments. The electrostatic potential minima in zwitterionic and nonzwitterionic forms of 1 are discussed in relation with the localization of possible metal chelation sites. 相似文献