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991.
Bernardo Monteiro Luís Cunha-Silva Sandra Gago Jacek Klinowski Filipe A. Almeida Paz João Rocha Isabel S. Gonçalves Martyn Pillinger 《Polyhedron》2010
The tetramethylammonium salts (NMe4)2[MO2(2,3-Hdhb)2]·2H2O and (NMe4)2[MO2(3,4-Hdhb)2]·6H2O (M = Mo, W; Hdhb = monoprotonated form of 2,3- or 3,4-dihydroxybenzoic acid, 2,3-H3dhb or 3,4-H3dhb) were prepared and their crystal structures determined. The structure of [Mg(H2O)6](NMe4)4[MoO2(3,4-dhb)(3,4-Hdhb)]2·13H2O, obtained by the recrystallization of (NMe4)2[MoO2(3,4-Hdhb)2] in the presence of magnesium ions, is also reported. The supramolecular interactions of the five structures are discussed in detail concerning the hydrogen bonding patterns involving complexes and water molecules of crystallization. 相似文献
992.
This critical review presents information on known and innovative approaches to the manufacture of fibre coatings used in solid-phase microextraction (SPME). The properties, advantages and drawbacks of the different types of commercially available SPME fibre coatings are discussed in detail, as are those of novel types of coatings and the methodologies of their preparation. The applications of fibre coatings in the solid-phase microextraction of a broad spectrum of analytes are analysed, with particular emphasis on the sampling of polar analytes from polar matrices (174 references). 相似文献
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Reaction rates of interfacial polycondensation of bisphenol A and chlorobisphenol II with isophthaloyl chloride were investigated. Rate constants and activation energies were determined The reaction rate was found to depend on stirring speed, catalyst, type of bisphenol, and temperature. 相似文献
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Jacek Blazewicz Edmund K. Burke Graham Kendall Wojciech Mruczkiewicz Ceyda Oguz Aleksandra Swiercz 《Annals of Operations Research》2013,207(1):27-41
In this paper we investigate the use of hyper-heuristic methodologies for predicting DNA sequences. In particular, we utilize Sequencing by Hybridization. We believe that this is the first time that hyper-heuristics have been investigated in this domain. A hyper-heuristic is provided with a set of low-level heuristics and the aim is to decide which heuristic to call at each decision point. We investigate three types of hyper-heuristics. Two of these (simulated annealing and tabu search) draw their inspiration from meta-heuristics. The choice function hyper-heuristic draws its inspiration from reinforcement learning. We utilize two independent sets of low-level heuristics. The first set is based on a previous tabu search method, with the second set being a significant extension to this basic set, including utilizing a different representation and introducing the definition of clusters. The datasets we use comprises two randomly generated datasets and also a publicly available biological dataset. In total, we carried out experiments using 70 different combinations of heuristics, using the three datasets mentioned above and investigating six different hyper-heuristic algorithms. Our results demonstrate the effectiveness of a hyper-heuristic approach to this problem domain. It is necessary to provide a good set of low-level heuristics, which are able to both intensify and diversify the search but this approach has demonstrated very encouraging results on this extremely difficult and important problem domain. 相似文献
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A version of the Girsanov theorem for the inhomogeneous Wiener process in the dual of a nuclear space is proved.It is then applied to the investigation of the existence and uniqueness of weak solutions of stochastic differential equations in this space. 相似文献