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排序方式: 共有512条查询结果,搜索用时 78 毫秒
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Jean-Christophe Breton 《Comptes Rendus Mathematique》2002,334(2):135-138
We are interested in the laws of multiple stable stochastic integrals defined by LePage series representation (see [1,6]). We continue the study begun in [1] giving conditions ensuring absolute continuity of joint laws of stable integrals. To this way, we apply a stratification method on the Skorokhod space on which we first take back the problem. To cite this article: J.-C. Breton, C. R. Acad. Sci. Paris, Ser. I 334 (2002) 135–138 相似文献
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The 2D Rancieite type manganic acid was prepared by reduction of KMnO4 in acidic medium. Its ion exchange behavior allows to prepare alkali derivatives. All compounds were characterized with use of a combination of X-ray diffraction, chemical analyses, TGA, magnetic measurements and spectroscopic techniques. The evolution of their chemical composition versus temperature was studied between 180 and 400 °C. It shows that the dehydration process is partly reversible in these compounds whereas the weak reduction is irreversible. The 2D Rancieite-type manganic acid is readily different from a Birnessite-type phyllomanganate, as shown by several features: the interlayer distance, the ion exchange capacity, the thermal behavior, the interlayer cation content, the manganese average oxidation state, the magnetic behavior and the IR spectrum. 相似文献
5.
Valérie Michaut Jean-Marc Paris Jean-Christophe Plaquevent 《Journal of fluorine chemistry》2007,128(8):889-895
Herein are studied new transformations of ethyl-4,4,4-trifluoroacetoacetate (ETFAA), giving access to a series of enantiopure chirons bearing both a trifluoromethyl group and an amino moiety. The key intermediate is obtained optically pure by a resolution procedure. 相似文献
6.
István E. MarkóJean-Christophe Vanherck Ali AtesBernard Tinant Jean-Paul Declercq 《Tetrahedron letters》2003,44(16):3333-3336
Upon treatment with tBuOK/H2O, a variety of ω-halo-β-keto-ketals undergo smooth cyclisation, affording in excellent yields mono-protected [n,m] spiro bicyclic diketones. This transformation is highly stereoselective producing, in all cases, the diastereoisomerically pure spiro derivatives. 相似文献
7.
Ylures sans sel,evolution en phosphoranes et equilibre ylure ⇌ phosphorane : I Synthese et structure
Synthesis of new salt-free ylids , to , , , , and and phoiphoranes , , , , , to by addition of a trivalent phosphorus compound (phosphites and amino-phosphines ) to with dimethyl acetylencedicartboxylate in presence of a protic trapping reagent are described. The results are consistent with trapping of carbanionic species. In relation with the. cyclic of acyclic structure of the triivalent phosphorus compound and the protic trapping reagent ie : methanol, phenol, carboxylic acid, etc.., several pathways are involved. Clearly), three phenomena are shown : one can obtain an ylid via a phosphorane or conversely a phosphorane via an ylid or an equilibrium Phoiphorane ? ylid. Results are dealing with thermodynamic or kinetically controlled reactions. 相似文献
8.
Carlier J Arscott S Thomy V Camart JC Cren-Olivé C Le Gac S 《Journal of chromatography. A》2005,1071(1-2):213-222
We report here on an integrated microfabricated device dedicated to the preparation of biological samples prior to their on-line analysis by electrospray ionization-mass spectrometry (ESI-MS). This microfluidic device is fabricated using the negative photoresist SU-8 by microtechnology techniques. The device includes a chromatographic module plus an ESI interface for MS. The chromatographic module is dedicated to sample purification and is based on a polymer monolithic phase which includes hydrophobic moieties. The ESI interface is integrated onto the chip and is based on a capillary slot. We present here the integration of these different modules onto a single system that is fabricated via a SU-8-based microtechnology route. We present also their testing for the purification of peptide samples. This started with a partial integration step with the combination of at least two of the modules (microsystem + monolith; microsystem + nib) and their test before the fabrication and testing of fully integrated microsystems. 相似文献
9.
The General Rate model has been developed and solved to describe protein adsorption in an expanded bed. The model takes into account axial and local variation of particle size distribution (PSD), external and intra-particle mass transfer resistances, and dispersion in liquid phase. The influence of PSD on breakthrough profiles has been analysed. The simulation results show that for a significantly high expanded bed the lower part of the breakthrough curve profiles, calculated for local particle size distribution (LPSD) and for axial average particle size distribution (APSD) are very similar. However, the upper part of breakthrough profiles calculated for LPSD approaches inlet concentration much more slowly than those calculated for APSD. The retention times of the lower part of uptake curves calculated with average particle diameter are constantly shorter than those obtained from LPSD. For the calculation of the dynamic capacity (DC), the LPSD can be replaced by APSD for large expanded bed heights. Using breakthrough profiles calculated for average particle size, DC values are constantly underestimated. 相似文献
10.
Side-on liquid crystal polyacrylate in Langmuir-Blodgett films 总被引:1,自引:0,他引:1
A side-on fixed liquid crystal polyacrylate has been investigated in Langmuir and Langmuir-Blodgett (LB) films. High in-plane orientation of the mesogenic groups has been observed within the LB multilayers, showing the ability of the LB technique to align a liquid crystal. The analysis of the in-plane order versus the dipping speed suggests some self-aggregation of the polymer in the monolayer. Within these aggregates, the molecular orientation (in-plane and out-plane) has been deduced from infrared dichroism experiments; the mesogenic group lies mainly parallel to the dipping direction and relatively flat on the substrate. This alignment of the polymer is however partially lost with time, leading to materials with less in-plane anisotropy. 相似文献