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11.
The existence of an attractor for a 2D-Navier-Stokes system with delay is proved. The theory of pullback attractors is successfully applied to obtain the results since the abstract functional framework considered turns out to be nonautonomous. However, on some occasions, the attractors may attract not only in the pullback sense but in the forward one as well. Also, this formulation allows to treat, in a unified way, terms containing various classes of delay features (constant, variable, distributed delays, etc.). As a consequence, some results for the autonomous model are deduced as particular cases of our general formulation. 相似文献
12.
13.
Christopher J. Nichols 《Tetrahedron letters》2004,45(40):7469-7473
A number of new functionalised bridged indolocarbazole systems have been prepared by ring-opening reactions of a key cyclic sulfate intermediate, prepared from the corresponding diol by the action of sulfuryl diimidazole and DBU. The same cyclic sulfate also undergoes an unprecedented asymmetric rearrangement to a chiral ketone, on treatment with a chiral lithium amide base. 相似文献
14.
C. Sparber J. A. Carrillo J. Dolbeault P. A. Markowich 《Monatshefte für Mathematik》2004,141(3):237-257
We analyze the long-time behavior of transport equations for a class of dissipative quantum systems with Fokker-planck type diffusion operator, subject to confining potentials of harmonic oscillator type. We establish the existence and uniqueness of a non-equilibrium steady state for the corresponding dynamics. Further, using a (classical) convex Sobolev inequality, we prove an optimal exponential rate of decay towards this state and additionally give precise dispersion estimates in those cases, where no stationary state exists. 相似文献
15.
Summary. We study a diffusion model of an interacting particles system with general drift and diffusion coefficients, and electrostatic
inter-particles repulsion. More precisely, the finite particle system is shown to be well defined thanks to recent results
on multivalued stochastic differential equations (see [2]), and then we consider the behaviour of this system when the number
of particles goes to infinity (through the empirical measure process). In the particular case of affine drift and constant diffusion coefficient,
we prove that a limiting measure-valued process exists and is the unique solution of a deterministic PDE. Our treatment of
the convergence problem (as ) is partly similar to that of T. Chan [3] and L.C.G. Rogers - Z. Shi [5], except we consider here a more general case allowing
collisions between particles, which leads to a second-order limiting PDE.
Received: 5 August 1996 / In revised form: 17 October 1996 相似文献
16.
17.
Magnetic Properties of the Cobaltates Na6CoS4, Na6CoSe4, and K6CoS4 The alkali metal cobalt chalcogenides Na6CoS4, Na6CoSe4, and K6CoS4 crystallize in the space group P63mc with Z = 4. The structure is characterized by isolated [CoX4]-tetrahedra. The magnetic susceptibilities show Curie-Weiss behaviour. The deviations at low temperatures are caused by antiferromagnetic interactions. The magnetic moments are discussed with regard to ligand-field parameters. 相似文献
18.
Kevin Houston 《Inventiones Mathematicae》2002,147(3):471-485
The disentanglement of certain augmentations is shown to be the topological join of a disentanglement and a Milnor fibre.
The kth disentanglement of a finite map is defined and for corank 1 maps from ℂ
n
to ℂ
n
+1 it is shown that they are homotopically equivalent to a wedge of spheres. Applications to the Mond conjecture are given.
Oblatum 24-VII-2000 & 5-VII-2001?Published online: 12 October 2001 相似文献
19.
Houman Borouchaki Abdelhakim Cherouat Patrick Laug Khemais Saanouni 《Comptes Rendus Mecanique》2002,330(10):709-716
The analysis of mechanical structures using the Finite Element Method in the framework of large elastoplastic strain, needs frequent remeshing of the deformed domain during computation. Indeed, the remeshing is due to the large geometrical distortion of finite elements and the adaptation to the physical behavior of the solution. This paper gives the necessary steps to remesh a mechanical structure during large elastoplastic deformations with damage. An important part of this process is constituted by geometrical and physical error estimates. The proposed method is integrated in a computational environment using the ABAQUS/Explicit solver and the BL2D-V2 adaptive mesher. To cite this article: H. Borouchaki et al., C. R. Mecanique 330 (2002) 709–716. 相似文献
20.
锰结核中硅,铝,铁,镁,磷,钾,锰,钛的XRFA 总被引:1,自引:0,他引:1
本文叙述了用XRF分析锰结核中Si、Al、Fe、Mg、P、K、Mn和Ti的方法。按照通常锰结核的主次成分制备6个人工合成标准,根据Sherman方程计算了已知成分(二元系统)的相对强度。用L-T方求得了互致元素校正的理论α系数(基本的、混合的、修正的),用DATAFLEX151B计算机以BASIC语言汇了“PRA,APU”计算机程序。然后进行非线性回归分析了锰结核样品得到了满意的结果。 相似文献