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961.
Anne‐Laure Brocas Gabriel Cendejas Sylvain Caillol Alain Deffieux Stephane Carlotti 《Journal of polymer science. Part A, Polymer chemistry》2011,49(12):2677-2684
Poly(allyl glycidyl ether) and poly(allyl glycidyl ether‐co‐epichlorohydrin) were prepared by monomer‐activated anionic polymerization. Quantitative and controlled polymerization of allyl glycidyl ether (AGE) giving high molar mass polyether was achieved in a few hours at room temperature in toluene using tetraoctylammonium salt as initiator in presence of an excess of triisobutylaluminum ([i‐Bu3Al]/[NOct4Br] = 2?4). Following the same polymerization route, the copolymerization of AGE and epichlorohydrin yields in a living‐like manner gradient‐type copolymers with controlled molar masses. Chemical modification of the pendant allyl group into cyclic carbonate was then investigated and the corresponding polymers were used as precursors for the isocyanate‐free synthesis of polyurethane networks in presence of a diamine. Formation of crosslinked materials was followed and characterized by infrared and differential scanning calorimetry. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
962.
Sylvain Brochard 《Advances in Mathematics》2012,229(3):1555-1585
We prove some finiteness theorems for the Picard functor of an algebraic stack, in the spirit of SGA 6, exp. XII and XIII. In particular, we give a stacky version of Raynaud?s relative representability theorem, we give sufficient conditions for the existence of the torsion component of the Picard functor, and for the finite generation of the Néron–Severi groups or of the Picard group itself. We give some examples and applications. In Appendix A, we prove the semicontinuity theorem for a (non-necessarily tame) algebraic stack. 相似文献
963.
964.
965.
966.
Hideki Hashimoto Sylvain Boussier Michel Vasquez Christophe Wilbaut 《Annals of Operations Research》2011,183(1):143-161
The Technicians and Interventions Scheduling Problem for Telecommunications embeds the scheduling of interventions, the assignment
of teams to interventions and the assignment of technicians to teams. Every intervention is characterized, among other attributes,
by a priority. The objective of this problem is to schedule interventions such that the interventions with the highest priority
are scheduled at the earliest time possible while satisfying a set of constraints like the precedence between some interventions
and the minimum number of technicians needed with the required skill levels for the intervention. We present a Greedy Randomized
Adaptive Search Procedure (GRASP) for solving this problem. In the proposed implementation, we integrate learning to the GRASP
framework in order to generate good-quality solutions using information brought by previous ones. We also compute lower bounds
and present experimental results that validate the effectiveness of this approach. 相似文献
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968.
A random heterogeneous material is represented by a finite family of microstructures, the environment of each microstructure being subjected to a perfect mix condition whose validity is justified both theoretically and numerically. Necessary conditions, satisfied by any permissible strain rate field on a representative and unlimited domain of the material, are highlighted. They enable one to obtain, by solving a discrete infmax problem, a lower bound of the effective yield strength domain of the material, that is rigorous and more predictive than the classical bound of Reuss. An analytical application on a porous medium illustrates the methodology. 相似文献
969.
Abstract A high pressure-mediated route for convergent, regiospecific syntheses of (±)-l1-deoxydaunomycinone and 4-demethoxy analog, by sequential Diels-Alder cycloadditions is described. 相似文献
970.
The multi-step synthesis of 1,3,7-trisubstituted pyrimido[1,2-a]pyrimidinediones starting from isothiocyanates is described. These nitrogen bicycles were prepared by an iterative sequence of functionalization/cyclocondensation reactions. [4+2] Cycloaddition reactions took place between diazadienic chains and various acyl chlorides providing sophisticated heterobicycles. 相似文献