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991.
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993.
Julien Rolland Pierre Guillet Jean‐Marc Schumers Nicolas Duhem Véronique Préat Jean‐François Gohy 《Journal of polymer science. Part A, Polymer chemistry》2012,50(21):4484-4493
Interpolymer polyelectrolyte complexes of chitosan (CS) with poly(acrylic acid) homopolymers and polystyrene‐block‐poly(acrylic acid) diblock copolymers were prepared and characterized. The influence of the positive/negative charge balance (charge ratio), pH, and ionic strength were thoroughly studied by dynamic light scattering. The existence of a strong polyelectrolyte effect was also highlighted in this study. Domains of stability, in which nanoparticle sizes are smaller than 100 and 200 nm for complexes of CS with the homopolymer and copolymer, respectively, were identified and confirmed by scanning electron microscopy and atomic force microscopy. The charged nature of the surface of the nanoparticles was evidenced by Zeta potential measurements. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
994.
The main objective of this study is to compare the influence of different boundary conditions upon the incompressible Poiseuille –Bénard channel flow (PBCF) in a 2D rectangular duct heated from below. In a first technical part the algorithm used to carry out this work, based on the augmented Lagrangian method, is presented. The implementation details of the five different open boundary conditions (OBCs) and the periodic boundary conditions (PBCs) tested in the present paper are also given. The study is then carried out for 1800<Ra≤ 10,000, 0<Re≤10 and 0·67≤Pr≤6·4. The five selected OBCs, applied at the outlet of the computational domain, respectively express the following conditions: a square profile for the velocity (OBC1), mass conservation (OBC2), zero second derivative of the horizontal velocity component (OBC3), a mixed boundary condition combining Dirichlet and Neumann conditions (OBC4) and an Orlanski-type boundary condition (OBC5). A good estimation of the perturbation amplitude and of the length of the perturbed zone at the outlet boundary is proposed. It is shown that OBC5 causes very little perturbation in the recirculating flow compared with the other OBCs. © 1997 John Wiley & Sons, Ltd. 相似文献
995.
996.
Annals of Global Analysis and Geometry - This paper is devoted to the classification of 4-dimensional Riemannian spin manifolds carrying skew Killing spinors. A skew Killing spinor $$psi $$ is a... 相似文献
997.
Lo?c?MazoEmail author Nicolas?Passat Michel?Couprie Christian?Ronse 《Acta Appl Math》2011,113(2):167-193
The development of digital imaging (and its subsequent applications) has led to consideration and investigation of topological
notions that are well-defined in continuous spaces, but not necessarily in discrete/digital ones. In this article, we focus
on the classical notion of path. We establish in particular that the standard definition of path in algebraic topology is
coherent w.r.t. the ones (often empirically) used in digital imaging. From this statement, we retrieve, and actually extend,
an important result related to homotopy-type preservation, namely the equivalence between the fundamental group of a digital
space and the group induced by digital paths. Based on this sound definition of paths, we also (re)explore various (and sometimes
equivalent) ways to reduce a digital image in a homotopy-type preserving fashion. 相似文献
998.
Nicolas Beldiceanu Mats Carlsson Sophie Demassey Emmanuel Poder 《Annals of Operations Research》2011,184(1):27-50
This article describes new filtering methods for the cumulative constraint. The first method introduces the so called longest closed hole and longest open hole problems. For these two problems it first provides bounds and exact methods and then shows how to use them in the context of the non-overlapping constraint. The second method introduces balancing knapsack constraints which relate the total height of the tasks that end at a specific time-point with the total height of the tasks that start at the same time-point. Experiments on tight rectangle packing problems show that these methods drastically reduce both the time and the number of backtracks for finding all solutions as well as for finding the first solution. For example, we found without backtracking all solutions to 65 perfect square instances of order 22?C25 and sizes ranging from 192×192 to 661×661. 相似文献
999.
Miklos Abert Nicolas Bergeron Ian Biringer Tsachik Gelander Nikolay Nikolov Jean Raimbault Iddo Samet 《Comptes Rendus Mathematique》2011,349(15-16):831-835
We announce new results concerning the asymptotic behavior of the Betti numbers of higher rank locally symmetric spaces as their volumes tend to infinity. Our main theorem is a uniform version of the Lück Approximation Theorem (Lück, 1994 [10]) which is much stronger than the linear upper bounds on Betti numbers given by Gromov in Ballmann et al. (1985) [3].The basic idea is to adapt the theory of local convergence, originally introduced for sequences of graphs of bounded degree by Benjamini and Schramm, to sequences of Riemannian manifolds. Using rigidity theory we are able to show that when the volume tends to infinity, the manifolds locally converge to the universal cover in a sufficiently strong manner that allows us to derive the convergence of the normalized Betti numbers. 相似文献
1000.
Antonio Fazzolari Nicolas R. Gauger Joël Brezillon 《Journal of Computational and Applied Mathematics》2007
Multidisciplinary analysis is necessary to reach physically meaningful optimum designs. For aero-structural shape optimization this means coupling two disciplines—aerodynamics and structural mechanics. In this paper, the sensitivity evaluation for aerodynamic shape optimization is considered, while taking into account the static aeroelastic effects introduced by the variations in the aerodynamic forces, which are associated with changes in the aerodynamic shape. Due to the high computational cost of a finite difference evaluation step for such a coupled problem, an extension of the adjoint approach to aeroelasticity is necessary for an efficient calculation of the sensitivities. The implementation, validation and application of such a method in the MDO context described above are presented. 相似文献