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991.
Stefania Gatti Maurizio Grasselli Alain Miranville Vittorino Pata 《Proceedings of the American Mathematical Society》2006,134(1):117-127
Given a dissipative strongly continuous semigroup depending on some parameters, we construct a family of exponential attractors which is robust, in the sense of the symmetric Hausdorff distance, with respect to (even singular) perturbations.
992.
An efficient one pot access to variously substituted thieno[2,3‐b]thiophene is described. The title compounds were obtained from 1,3‐dicarbonyl or equivalent compounds, carbon disulfide and halomethyl derivatives in good to high yields and fully characterized. 相似文献
993.
P l Herczegh Imre Kov cs L szl Szil gyi Ferenc Sztaricskai
Amaya Berecibar
Claude Riche Ang le Chiaroni Alain Olesker Gabor Lukacs 《Tetrahedron》1994,50(48):13671-13686Diastereoselective hetero Diels-Alder reactions of sugar derived azomethines 4a–4g have been used for the construction of chiral piperidones 6 and 7. Configuration of the major products was 6,1′-threo in every case. The enone system of 6 and 7 was reduced diastereoselectively and subsequently swainsonine-analog hydroxyindolizidines 28–32 were prepared by an intramolecular reductive amination. 相似文献
994.
Alain Hach Mohit Malik Marcus Diem Lasha Tkeshelashvili Kurt Busch 《Photonics and Nanostructures》2007,5(1):29-36
We show that the sensitivity to disorder of certain physical properties of periodic media depends on whether the disorder is truly random or not. This allows to utilize periodic media for testing sequences of random numbers and to quantify their departure from true randomness via simple transmission and/or reflection data analysis. This physics-based model shows promises for device applications to test random data. 相似文献
995.
We generalize to the bandwidth coloring problem a classical theorem, discovered independently by Gallai, Roy and Vitaver, in the context of the graph coloring problem. Two proofs are given, a simple one and a more complex one that is based on a series of equivalent mathematical programming models. 相似文献
996.
997.
Judit E. Puskas Frédéric Peruch Alain Deffieux David E. Dabney Chrys Wesdemiotis Haibo Li Allia Lindsay 《Journal of polymer science. Part A, Polymer chemistry》2009,47(8):2172-2180
Natural rubber (poly(1,4‐cis‐isoprene), NR) is a polymer of considerable industrial importance due to its exceptional properties. It is mostly produced from the cultivation of Hevea brasiliensis, and to a limited extent from Parthenium argentatum. Till date none of the synthetic equivalent of NR exists. Recently we suggested that the mechanism of NR biosynthesis is based on carbocationic polymerization, similarly to that of natural oligoisoprenoids forming by enzyme‐catalyzed prenylation. In this article we present proof of concept of a new bio‐inspired synthetic route towards the synthesis of polyisoprenes based on carbocationic polymerization initiated by dimethyl allyl bromide (DMABr)/TiCl4. It is shown that using this strategy, 1,4‐oligoisoprene carrying a dimethyl allyl head group is produced in both cis and trans configurations, together with cyclized sequences. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2172–2180, 2009 相似文献
998.
999.
The results of single crystal X‐ray structure determinations are reported for Ba2CaCuV2F14 (a = 1383.6(3), b = 540.89(8), c = 1493.1(3) pm, β = 91.65(3)°) and Ba2CaCuCr2F14 (a = 1381.1(5), b = 535.5(1), c = 1481.4(6) pm, β = 91,50(4)°), both isotypic with usovite (space group C2/c, Z = 4). The resulting average distances are V‐F: 193.8 pm, Cr‐F: 190.7 pm, and Cu‐F: 209.2 resp. 207.1 pm for the Jahn‐Teller elongated [CuF6] octahedra. Within the cross‐linked double chains of octahedra F‐bridged trimers M‐Cu‐M, magnetically studied earlier, are confirmed and discussed. 相似文献
1000.
By studying the geometry of relevant Hilbert spaces, we give a characterization of the identifiable standard representations of multivariate ARMA models in terms of the autocovariance function. 相似文献