搜索结果: 121-135 共查到“理学 diffusion”相关记录344条 . 查询时间(0.375 秒)
A finite volume method on general meshes for a degenerate parabolic convection-reaction-diffusion equation
parabolic convection-reaction-diffusion equation math
2010/11/23
We propose a finite volume method on general meshes for the discretization of a degenerate parabolic convection-reaction-diffusion equation. Equations of this type arise in many contexts, such as the ...
Diffusion-limited reactions on a two-dimensional lattice with binary disorder
Diffusion-limited reactions two-dimensional lattice with binary disorder
2010/11/19
Reaction-diffusion systems where transition rates exhibit quenched disorder are common in physical and chemical systems. We study pair reactions on a periodic two-dimensional lattice, including contin...
Reduction operators of variable coefficient semilinear diffusion equations with an exponential source
Exactly Solvable and Integrable Systems (nlin.SI) Mathematical Physics (math-ph)
2010/11/10
Reduction operators (called also nonclassical or $Q$-conditional symmetries) of variable coefficient semilinear reaction-diffusion equations with exponential source $f(x)u_t=(g(x)u_x)_x+h(x)e^{mu}$ ar...
Entropy-driven enhanced self-diffusion in confined reentrant supernematics
Entropy-driven enhanced self-diffusion confined reentrant supernematics
2010/11/17
We present a molecular dynamics study of reentrant nematic phases using the Gay-Berne-Kihara
model of a liquid crystal in nanoconfinement. At densities above those characteristic of smectic A phases,...
Large-amplitude chirped coherent phonons in tellurium mediated by ultrafast photoexcited carrier diffusion
Large-amplitude chirped coherent phonons tellurium ultrafast photoexcited carrier diffusion
2010/11/17
We report femtosecond time-resolved reflectivity measurements of coherent phonons in tellurium
performed over a wide range of temperatures (3K to 296K) and pump laser intensities. A totally
symmetri...
Magnetic Diffusion in Star Formation
MHD turbulence waves stars formation ISM clouds ISM magnetic fields
2010/11/10
Magnetic diffusion plays a vital role in star formation. We trace its influence from interstellar cloud scales down to star-disk scales. On both scales, we find that magnetic diffusion can be signific...
A finite volume scheme for convection-diffusion equations with nonlinear diffusion derived from the Scharfetter-Gummel scheme
convection-diffusion equations nonlinear diffusion derived Scharfetter-Gummel scheme
2010/11/15
We propose a finite volume scheme for convection-diffusion equations with nonlinear diffusion. Such equations arise in numerous physical contexts. We will particularly focus on the drift-diffusion sy...
A posteriori error estimator based on gradient recovery by averaging for convection-diffusion-reaction problems approximated by discontinuous Galerkin methods
averaging convection-diffusion-reaction problems discontinuous Galerkin methods
2010/11/9
We consider some (anisotropic and piecewise constant) convection-diffusion-reaction problems in domains of R2, approximated by a discontinuous Galerkin method with polynomials of any degree. We propos...
p, He, and C to Fe cosmic-ray primary fluxes in diffusion models: Source and transport signatures on fluxes and ratios
Methods statistical – ISM cosmic rays
2010/11/10
Context. The source spectrum of cosmic rays is not well determined by diffusive shock acceleration models. The prop-agated fluxes of proton, helium, and heavier primary cosmic-ray species (up to Fe) a...
Time Reversal of Some Stationary Jump-Diffusion Processes from Population Genetics
Jump-Diffusion Processes Population Genetics
2010/11/19
We describe the processes obtained by time reversal of a class of stationary jump-diffusion processes that model the dynamics of genetic variation in populations subject to repeated bottlenecks. Assu...
Positive solutions of some parabolic system with cross-diffusion and nonlocal initial conditions
Positive solutions parabolic system cross-diffusion nonlocal initial conditions
2010/11/19
The paper is concerned with a system consisting of two coupled nonlinear parabolic equations with a cross-diffusion term, where the solutions at positive times define the initial states. The equation...
Effects of spatial structure and diffusion on the performances of the chemostat
spatial structure the chemostat
2010/11/22
Given hydric capacity and nutrient flow of a chemostat-like system, we analyse the influence of a spatial structure on the output concentrations at steady-state. Three configurations are compared: pe...
Matching Statistics of an Itô Process by a Process of Diffusion Type
Matching Statistics Process of Diffusion Type
2010/11/8
Suppose we are given a multi-dimensional It\^o process, which can be regarded as a model for an underlying asset price together with related stochastic processes, e.g., volatility. The drift and diff...
MHD Simulations of Parker Instability Undergoing Cosmic-Ray Diffusion: Effect of the Initial Equilibrium Conditions on Mixing
cosmic rays magnetohydrodynamics instability numerical simulation
2010/11/9
Parker instability arises from the presence of magnetic fields in a plasma such as the interstellar medium (ISM),wherein the magnetic buoyant pressure expels the gas and causes the gas to move along t...
Simulating Heliospheric and Solar Particle Diffusion using the Parker Spiral Geometry
Simulating Heliospheric Solar Particle Diffusion Parker Spiral Geometry
2010/11/16
Cosmic Ray transport in curved background magnetic fields is investigated using numerical Monte-Carlo simulation techniques. Special emphasis is laid on the So-lar system, where the curvature of the m...