共查询到20条相似文献,搜索用时 15 毫秒
1.
Piotr Biler Grzegorz Karch Régis Monneau 《Communications in Mathematical Physics》2010,294(1):145-168
We study a nonlinear pseudodifferential equation describing the dynamics of dislocations in crystals. The long time asymptotics
of solutions is described by the self-similar profiles. 相似文献
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采用MonteCarlo方法,研究了正二十面体结构的Cu、Ni、Pd和Pt等金属团簇在Pd(001)表面的稳定性和扩散行为.研究表明,载体对负载型金属团簇的稳定性和扩散性质有明显的影响.由于载体表面和金属团簇的振动偶合,金属团簇结构变化的温度要低于自由团簇的结构转化温度.负载型金属团簇的稳定性不仅取决于团簇内部原子之间的相互作用而且取决于团簇与载体之间的相互作用.对金属团簇扩散的研究表明,金属团簇的扩散常数与单金属原子的扩散常数相差不大,通过比较金属团簇的结构变化温度和扩散常数发现,团簇的稳定性和扩散行为有密切的联系. 相似文献
4.
SI Tie-Yan DUAN Yi-Shi 《理论物理通讯》2006,46(2):319-322
We propose a general method of deterrnining the distribution of topological defects on axisymmetric surface, and study the distribution of topological defects on biconcave-discoid surface, which is the geometric configuration of red blood cell. There are three most possible cases of the distribution of the topological defects on the biconcave surface: four defects charged with 1/2, two defects charged with +1, or one defect charged with 2. For the four defect charged with 1/2, they sit at the vertices of a square imbedded in the equator of biconcave surface. 相似文献
5.
SI Tie-Yan DUAN Yi-Shi 《理论物理通讯》2006,46(8)
We propose a general method of determining the distribution of topological defects on axisymmetric surface,and study the distribution of topological defects on biconcave-discoid surface, which is the geometric configuration of red blood cell. There are three most possible cases of the distribution of the topological defects on the biconcave surface:four defects charged with 1/2, two defects charged with 1, or one defect charged with 2. For the four defect charged with 1/2, they sit at the vertices of a square imbedded in the equator of biconcave surface. 相似文献
6.
Ovidiu Costin Roland Donninger Irfan Glogić Min Huang 《Communications in Mathematical Physics》2016,343(1):299-310
We consider an explicit self-similar solution to an energy-supercritical Yang-Mills equation and prove its mode stability. Based on earlier work by one of the authors, we obtain a fully rigorous proof of the nonlinear stability of the self-similar blowup profile. This is a large-data result for a supercritical wave equation. Our method is broadly applicable and provides a general approach to stability problems related to self-similar solutions of nonlinear wave equations. 相似文献
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M. Nawaz & T. Hayat 《advances in applied mathematics and mechanics.》2014,6(2):220-232
This paper investigates the laminar boundary
layer flow of nanofluid induced by a radially stretching sheet. Nanofluid
model exhibiting Brownian motion and thermophoresis is used. Series
solutions for a reduced system of nonlinear ordinary differential equations
are obtained by homotopy analysis method (HAM). Comparative study between
the HAM solutions and previously published numerical results shows an
excellent agreement. Velocity, temperature and mass fraction are displayed
for various values of parameters. The local skin friction coefficient, the
local Nusselt number and the local Sherwood number are computed. It is
observed that the presence of nanoparticles enhances the thermal
conductivity of base fluid. It is found that the convective heat transfer
coefficient (Nusselt number) is decreased with an increase in concentration
of nanoparticles whereas Sherwood number increases when concentration of
nanoparticles in the base fluid is increased. 相似文献
9.
The axisymmetric time-fractional diffusion equation with mass absorption is studied in a circle under the time-harmonic Dirichlet boundary condition. The Caputo derivative of the order is used. The investigated equation can be considered as the time-fractional generalization of the bioheat equation and the Klein–Gordon equation. Different formulations of the problem for integer values of the time-derivatives and are also discussed. The integral transform technique is employed. The outcomes of numerical calculations are illustrated graphically for different values of the parameters. 相似文献
10.
In their stochastic versions, dynamical systems take the form of the linear dynamics of a probability distribution. We show that exact dimensional reduction of such systems can be carried out, and is physically relevant when the dimensions to be eliminated can be identified with those that represent transient behavior, disappearing under typical coarse graining. Application is made to non-uniform quasi-low dimensional diffusion, resulting in a systematic extension of the “classical” Fick-Jacobs approximate reduction to an exact subdynamics. 相似文献
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Robert L. Oldershaw 《International Journal of Theoretical Physics》1989,28(6):669-694
After calling attention to the empirical and theoretical motivations for considering the hypothesis of a self-similar cosmos, the basic concepts and scaling rules of the Self-Similar Cosmological Model are presented. The results of a diverse set of 20 falsification tests are then shown to provide strong quantitative support for the uniqueness and broad applicability of the self-similar scale transformation equations, which successfully correlate physical parameters of atomic, stellar, and galactic scale systems. Possible implications of these results are discussed. 相似文献
13.
The proposed explanations are provided for the one–dimensional diffusion process with constant drift by using forward Fokker–Planck
technique. We present the exact calculations and numerical evaluation to get the outflow probability in a finite interval,
i.e. first passage time probability density distribution taking into account reflecting boundary on left hand side and absorbing
border on right hand side. This quantity is calculated from balance equation which follows from conservation of probability.
At first, the initial-boundary-value problem is solved analytically in terms of eigenfunction expansion which relates to Sturm–Liouville
analysis. The results are obtained for all possible values of drift (positive, zero, negative). As application we get the
cumulative breakdown probability which is used in theory of traffic flow.
PACS numbers: 02.60.Lj, 02.50.–r, 02.50.Fz, 02.50.Ga 相似文献
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15.
Pantelis S. Apostolopoulos Michael Tsamparlis 《General Relativity and Gravitation》2003,35(11):2051-2056
It is shown that in transitively self-similar spatially homogeneous tilted perfect fluid models the symmetry vector is not normal to the surfaces of spatial homogeneity. A direct consequence of this result is that there are no self-similar Bianchi VIII and IX tilted perfect fluid models. Furthermore the most general Bianchi VIII and IX spacetime which admits a four dimensional group of homotheties is given. 相似文献
16.
Novak IL Gao F Choi YS Resasco D Schaff JC Slepchenko BM 《Journal of computational physics》2007,226(2):1271-1290
An algorithm is presented for solving a diffusion equation on a curved surface coupled to diffusion in the volume, a problem often arising in cell biology. It applies to pixilated surfaces obtained from experimental images and performs at low computational cost. In the method, the Laplace-Beltrami operator is approximated locally by the Laplacian on the tangential plane and then a finite volume discretization scheme based on a Voronoi decomposition is applied. Convergence studies show that mass conservation built in the discretization scheme and cancellation of sampling error ensure convergence of the solution in space with an order between 1 and 2. The method is applied to a cell-biological problem where a signaling molecule, G-protein Rac, cycles between the cytoplasm and cell membrane thus coupling its diffusion in the membrane to that in the cell interior. Simulations on realistic cell geometry are performed to validate, and determine the accuracy of, a recently proposed simplified quantitative analysis of fluorescence loss in photobleaching. The method is implemented within the Virtual Cell computational framework freely accessible at www.vcell.org. 相似文献
17.
The statics and dynamics of vacancies and adatoms on different surface orientations in two hcp materials are studied by using static relaxation techniques and many-body potentials. Formation and migration energies and entropies as well as attempt frequencies are evaluated and used in the random walk approach to obtain correlation factors and diffusivities. It is found that the main features of surface diffusion are dominated by jumps on and between a few atomic layers, so that a consistent comparison between the two mechanisms is feasible. The activation energies and the diffusivities for different environments, namely, bulk Q
b, D
b, symmetric grain boundaries Q
gb, D
gb, and surfaces, Q
s, D
s, calculated using the same simulation technique and interatomic potentials, fulfil the expected relationships Q
s < Q
gb < Q
b and D
s > D
gb > D
b. It is also found that generally adatoms are faster surface diffusers than vacancies. 相似文献
18.
Goro Akagi 《Communications in Mathematical Physics》2016,345(1):77-100
The stability of asymptotic profiles of solutions to the Cauchy–Dirichlet problem for fast diffusion equation (FDE, for short) is discussed. The main result of the present paper is the stability of any asymptotic profiles of least energy. It is noteworthy that this result can cover non-isolated profiles, e.g., those for thin annular domain cases. The method of proof is based on the ?ojasiewicz–Simon inequality, which is usually used to prove the convergence of solutions to prescribed limits, as well as a uniform extinction estimate for solutions to FDE. Besides, local minimizers of an energy functional associated with this issue are characterized. Furthermore, the instability of positive radial asymptotic profiles in thin annular domains is also proved by applying the ?ojasiewicz–Simon inequality in a different way. 相似文献
19.
Anders Szepessy 《Communications in Mathematical Physics》1999,202(3):547-569
One dimensional weak detonation waves of a basic reactive shock wave model are proved to be nonlinearly stable, i.e. initially
perturbed waves tend asymptotically to translated weak detonation waves. This model system was derived as the low Mach number
limit of the one component reactive Navier-Stokes equations by Majda and Roytburd [SIAM J. Sci. Stat. Comput. 43, 1086–1118 (1983)], and its weak detonation waves have been numerically observed as stable. The analysis shows in particular
the key role of the new nonlinear dynamics of the position of the shock wave, The shock translation solves a nonlinear integral
equation, obtained by Green's function techniques, and its solution is estimated by observing that the kernel can be split
into a dominating convolution operator and a remainder. The inverse operator of the convolution and detailed properties of
the traveling wave reduce, by monotonicity, the remainder to a small L
1 perturbation.
Received: 17 August 1998 / Accepted: 13 November 1998 相似文献
20.
Finding the building blocks of real-world networks contributes to the understanding of their formation process and related dynamical processes, which is related to prediction and control tasks. We explore different types of social networks, demonstrating high structural variability, and aim to extract and see their minimal building blocks, which are able to reproduce supergraph structural and dynamical properties, so as to be appropriate for diffusion prediction for the whole graph on the base of its small subgraph. For this purpose, we determine topological and functional formal criteria and explore sampling techniques. Using the method that provides the best correspondence to both criteria, we explore the building blocks of interest networks. The best sampling method allows one to extract subgraphs of optimal 30 nodes, which reproduce path lengths, clustering, and degree particularities of an initial graph. The extracted subgraphs are different for the considered interest networks, and provide interesting material for the global dynamics exploration on the mesoscale base. 相似文献