排序方式: 共有93条查询结果,搜索用时 15 毫秒
21.
We prove a complete converse of Aliprantis and Burkinshaw’s Theorem [2]. Also we obtain a generalization of Wickstead’s Theorem
[9] about this converse, and we give some interesting consequences.
revised 4 April, 18 October, and 26 December 2005 相似文献
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23.
Olivier Assemat Marie-Aude Coutouly Redouane Hajjar Marc-André Delsuc 《Comptes Rendus Chimie》2010,13(4):412-415
The validation of molecular mass measurements by using DOSY spectrocopy is presented. A mixture of oligosaccharides has been studied and an extended model has been used. A method has been proposed and applied to correct the imperfections due either to the lock system or the room temperature regulator. 相似文献
24.
Redouane Chebout Didier Tichit Géraldine Layrac Akila Barama Bernard Coq Iuliana Cota Eliana Ramirez Rangel Francisco Medina 《Solid State Sciences》2010,12(6):1013-1017
A new route for the preparation of basic mixed oxides using nanocomposite precursors obtained from layered double hydroxides (LDH) was investigated. These nanocomposites have been prepared by intercalation of negatively charged guest entities containing Ca2+, Sr2+, Ba2+ or La3+ cations in the interlayer space of host Mg/Al LDH by anionic exchange. The guest entities have been previously prepared by complexation of the required cations in the presence of edta or citrate chelating anions. Intercalation of [Mn+(edta)](4?n)? or [La(cit)OH]? complexes is proved by elemental analysis, XRD analysis and FT-IR spectroscopy. However, in order to satisfy the charge equilibrium in the materials, (edta)4? and (citrate)3? species are also co-intercalated in the nanocomposites. The basic properties of the mixed oxides obtained after thermal decomposition of the nanocomposites precursors were evaluated in the disproportionation of 2-methyl-3-butyn-2-ol (MBOH) and the transesterification of 1-phenylethanol with diethylcarbonate (DEC). The Sr- and Ba-containing mixed oxides exhibit basicity close to the one of MgO and Mg(La)O mixed oxides. A comparative study of the reactivity of La-containing mixed oxides obtained following different preparation routes, i.e. coprecipitation or anionic exchange, allows to conclude that the nanocomposite route led to the most active samples. 相似文献
25.
In the present study, multifractality and its formalism were employed to investigate the surface characteristics of an asphaltene deposited heterogeneous solid surface. Wettability alteration of the solid surface was found to affect the multifractal characteristics of an asphaltene deposited heterogeneous surface. Multifractal spectra f(α) show that the more oil wet the surface, the wider the spectrum, and the higher the fmax. The notable distinction between the multifractal spectra associated with different surface wettabilities can be used as a new aspect of wettability alteration. 相似文献
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We establish necessary and sufficient conditions under which the linear span of positive AM-compact operators (in the sense
of Fremlin) from a Banach lattice E into a Banach lattice F is an order σ-complete vector lattice. 相似文献
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[reaction: see text] We describe a synthesis of a dendrimer-like amphiphile containing a flat rigid core and 12 hydrophobic and hydrophilic arms. We employ a modular approach based on stepwise protection chemistry starting from simple building blocks. The key feature of this approach is the absence of a polymerization step, which makes it applicable for linear monofunctionalized precursors of any kind. This strategy also allows for precise control of the number of arms and ensures their alternating arrangement. 相似文献
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Redouane Qesmi 《Journal of Applied Analysis & Computation》2018,8(1):296-330
In this survey, we collect a few results scatted in the literature covering advances in systems of periodic delay differential equations including both modeling and theory. We will present the (almost) most oldest and (almost) most recent contributions made for this subject. 相似文献
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Positivity - We introduce and study a new topology on trees, that we call the countably coarse wedge topology. Such a topology is strictly finer than the coarse wedge topology and it turns every... 相似文献
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Belmesnaoui Aqzzouz Redouane Nouira 《Rendiconti del Circolo Matematico di Palermo》2005,54(3):381-386
We give a construction of a category which is stable for injective and countable inductive limits and for countable projective
limits, and we prove the bornological DeWilde theorem.
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