We study the dynamics of chemically or biologically active particles advected by open flows of chaotic time dependence, which can be modeled by a random time dependence of the parameters on a stroboscopic map. We deve...
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We study the dynamics of chemically or biologically active particles advected by open flows of chaotic time dependence, which can be modeled by a random time dependence of the parameters on a stroboscopic map. We develop a general theory for reactions in such random flows, and derive the reaction equation for this case. We show that there is a singular enhancement of the reaction in random flows, and this enhancement is increased as compared to the nonrandom case. We verify our theory in a model flow generated by four point vortices moving chaotically.
The Chebyshev pseudospectral approximation of the homogeneous initial boundary value problem for a class of multi-dimensional generalized symmetric regularized long wave (SRLW) equations is considered. The fully discr...
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The Chebyshev pseudospectral approximation of the homogeneous initial boundary value problem for a class of multi-dimensional generalized symmetric regularized long wave (SRLW) equations is considered. The fully discrete Chebyshev pseudospectral scheme is constructed. The convergence of the approximation solution and the optimum error of approximation solution are obtained.
The time periodic solution problem of damped generalized coupled nonlinear wave equations with periodic boundary condition was studied. By using the Galerkin method to construct the approximating sequence of time peri...
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The time periodic solution problem of damped generalized coupled nonlinear wave equations with periodic boundary condition was studied. By using the Galerkin method to construct the approximating sequence of time periodic solutions, a priori estimate and Laray_Schauder fixed point theorem to prove the convergence of the approximate solutions, the existence of time periodic solutions for a damped generalized coupled nonlinear wave equations can be obtained.
In this paper the qualitative analysis methods of planar autonomous systems and numerical simu-lation are used to investigate the peaked wave solutions of CH-r equation. Some explicit expressions of peakedsolitary wav...
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In this paper the qualitative analysis methods of planar autonomous systems and numerical simu-lation are used to investigate the peaked wave solutions of CH-r equation. Some explicit expressions of peakedsolitary wave solutions and peaked periodic wave solutions are obtained, and some of their relationships arerevealed. Why peaked points are generated is discussed.
By using ab initio methods on different levels we study the magnetic ground state of (finite) atomic wires deposited on metallic surfaces. A phenomenological model based on symmetry arguments suggests that the magneti...
By using ab initio methods on different levels we study the magnetic ground state of (finite) atomic wires deposited on metallic surfaces. A phenomenological model based on symmetry arguments suggests that the magnetization of a ferromagnetic wire is aligned either normal to the wire and, generally, tilted with respect to the surface normal or parallel to the wire. From a first-principles point of view, this simple model can be best related to the so-called magnetic force theorem calculations being often used to explore magnetic anisotropy energies of bulk and surface systems. The second theoretical approach that we use to search for the canted magnetic ground state is the first-principles adiabatic spin dynamics technique extended to the case of fully relativistic electron scattering. First, for the case of two adjacent Fe atoms on a Cu(111) surface we demonstrate that the reduction of the surface symmetry can indeed lead to canted magnetism. The anisotropy constants and consequently the ground state magnetization direction are very sensitive to the position of the dimer with respect to the surface. We also performed calculations for a seven-atom Co chain placed along a step edge of a Pt(111) surface. As far as the ground state spin orientation is concerned, we obtain excellent agreement with experiment. Moreover, the magnetic ground state turns out to be slightly non-collinear.
We present a new formulation of the incompressible Navier-Stokes equation in terms of an auxiliary field that differs from the velocity by a gauge transformation. The gauge freedom allows us to assign simple and speci...
A new iterative method,which is called positive interior-point algorithm,is presented for solving the nonlinear complementarity *** method is of the desirable feature of *** the convergence theorems of the algorithm i...
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A new iterative method,which is called positive interior-point algorithm,is presented for solving the nonlinear complementarity *** method is of the desirable feature of *** the convergence theorems of the algorithm is *** addition,some numerical results are reported.
We study a fluid jet descending through stratified surroundings at low Reynolds number in Hele-Shaw flow. The jet buckles and overturns inside a conduit of entrained fluid which supports smooth or unstable traveling w...
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We study a fluid jet descending through stratified surroundings at low Reynolds number in Hele-Shaw flow. The jet buckles and overturns inside a conduit of entrained fluid which supports smooth or unstable traveling waves. A model of the recirculating flow within the conduit shows that buckling and waves arise from Kelvin-Helmholtz instabilities and quantitatively accounts for the main experimental observations. Beyond the onset of the instability, a damped, forced Burgers’ equation obtained from corrections to Darcy’s law for small Reynolds number governs the interface dynamics and supports singularities corresponding to the observed jet overturning and unstable waves.
The Bell–Clauser-Horne-Shimony-Holt (BCHSH) inequality (in terms of correlation functions) of two qutrits is studied in detail by employing tritter measurements. A uniform formula for the maximum value of this inequa...
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The Bell–Clauser-Horne-Shimony-Holt (BCHSH) inequality (in terms of correlation functions) of two qutrits is studied in detail by employing tritter measurements. A uniform formula for the maximum value of this inequality for tritter measurements is obtained. Based on this formula, we show that nonmaximally entangled states violate the BCHSH inequality more strongly than the maximally entangled one. This result is consistent with what was obtained by Acín et al. [Phys. Rev. A 65, 052325 (2002)] using the Bell–Clauser-Horne inequality (in terms of probabilities).
The continuum distorted‐wave eikonal initial‐state (CDW‐EIS) theory of Crothers and McCann (1983) used to describe ionization in ion‐atom collisions is generalised (G) to GCDW‐EIS, to incorporate the azimuthal an...
The continuum distorted‐wave eikonal initial‐state (CDW‐EIS) theory of Crothers and McCann (1983) used to describe ionization in ion‐atom collisions is generalised (G) to GCDW‐EIS, to incorporate the azimuthal angle dependence of each CDW in the final state wave function. This is accomplished by the analytic continuation of hydrogenic‐like wave functions from below to above threshold, using parabolic coordinates and quantum numbers including magnetic quantum numbers, thus providing a more complete set of states. At impact energies lower than 25 keVu−1, the total ionization cross section falls off, with decreasing energy, too quickly in comparison with experimental data. The idea behind and motivation for the GCDW‐EIS model is to improve the theory with respect to experiment, by including contributions from non‐zero magnetic quantum numbers. We also therefore incidentally provide a new derivation of the theory of continuum distorted waves for zero magnetic quantum numbers while simultaneously generalising it. Comparison of our theoretical calculations are made with available experimental data.
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