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991.
992.
993.
Christian Bourdarias Stphane Gerbi Jacques Ohayon 《Mathematical and Computer Modelling》2009,49(11-12):2170-2181
Recent studies in mammalian hearts show that left ventricular wall thickening is an important mechanism for systolic ejection, and that during contraction the cardiac muscle develops significant stresses in the muscular cross-fiber direction. We suggested that the collagen network surrounding the muscular fibers could account for these mechanical behaviors. To test this hypothesis we develop a model for large deformation response of active, incompressible, nonlinear elastic and transversely isotropic living soft tissue (such as cardiac or arteries tissues) in which we include a coupling effect between the connective tissue and the muscular fibers. Then, a three-dimensional finite element formulation including this internal pseudo-active kinematic constraint is derived. Analytical and finite element solutions are in a very good agreement. The numerical results show this wall thickening effect with an order of magnitude compatible with the experimental observations. 相似文献
994.
995.
Pietro Franceschi Roland Thissen Odile Dutuit Christian Alcaraz Heloise Soldi-Lose Davide Bassi Daniela Ascenzi Paolo Tosi Jan Zabka Zdenek Herman Marcello Coreno Monica de Simone 《International journal of mass spectrometry》2009,280(1-3):119
The long-lived excited states of doubly charged rare gases can markedly affect their reactivity. In this paper we demonstrate the presence of strong state-specific effects in the charge exchange of Ar2+ (3P, 1D and 1S) with several neutral targets (He, Ne, Kr, Xe, D2, and CH4). State sensitive measurements have been performed by producing the different Ar2+ electronic states via tunable synchrotron radiation (Elettra-Trieste, Italy and SuperACO-Orsay, France). From the product ion yield data of charge transfer, state-selected total cross-sections have been deduced. Using the state-specific reactivity of Ar2+ towards different neutral targets, it has been possible to extract the photon-energy-dependent production branching of the three doubly charged states and to investigate the autoionization dynamics of neutral or singly charged Ar in the vicinity of the double ionization threshold. 相似文献
996.
We give an asymptotic formula for the distribution of those integers n in a residue class, such that n has a fixed sum of base-g digits, with some uniformity over the choice of the modulus and g. We then use this formula to solve the problem of I. Niven of giving an asymptotic formula for the distribution of those integers n divisible by the sum of their base-g digits. Our results also allow us to give a stronger form of a result of M. Olivier dealing with the distribution of integers with a given gcd with their sum of base-g digits.For our friend Jean-Louis Nicolas on his sixtieth birthdayResearch partially supported by the Hungarian National Foundation for Scientific Research, Grant No. T029759, and “Balaton” French-Hungarian exchange program F-18/00.2000 Mathematics Subject Classification: Primary—11A63 相似文献
997.
Christian Richter 《Journal of Geometry》2008,89(1-2):130-137
998.
Christian Pötzsche 《Journal of Differential Equations》2008,245(5):1210-1242
We derive a linearization theorem in the framework of dynamic equations on time scales. This extends a recent result from [Y. Xia, J. Cao, M. Han, A new analytical method for the linearization of dynamic equation on measure chains, J. Differential Equations 235 (2007) 527-543] in various directions: Firstly, in our setting the linear part need not to be hyperbolic and due to the existence of a center manifold this leads to a generalized global Hartman-Grobman theorem for nonautonomous problems. Secondly, we investigate the behavior of the topological conjugacy under parameter variation.These perturbation results are tailor-made for future applications in analytical discretization theory, i.e., to study the relationship between ODEs and numerical schemes applied to them. 相似文献
999.
Christian Lubich. 《Mathematics of Computation》2005,74(250):765-779
The Dirac-Frenkel-McLachlan variational principle is the basic tool for obtaining computationally accessible approximations in quantum molecular dynamics. It determines equations of motion for an approximate time-dependent wave function on an approximation manifold of reduced dimension. This paper gives a near-optimality result for variational approximations. It bounds the error in terms of the distance of the exact wave function to the approximation manifold and identifies the parameters that control the deviation of the variational approximation from the best approximation on the manifold.
1000.
In real catalyst systems, it is difficult to establish a correlation between catalytic properties and the shape (crystal planes, corners and steps) of the active catalytic particles. In this paper we present a clear shape dependence of the catalytic properties of a Vulcan‐supported fuel cell catalyst having 4 nm cubo‐octahedral platinum(0) nanocrystallites with (111) and (100) surfaces stabilized by sodium polyacrylate. The electrode materials were characterized by CO‐stripping cyclic voltammetry and transmission electron microscopy (TEM), showing that no agglomeration had occurred among the nanoparticles on the catalyst surfaces. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献