共查询到20条相似文献,搜索用时 15 毫秒
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Micol Amar Daniele Andreucci Paolo Bisegna Roberto Gianni 《Comptes Rendus Mecanique》2003,331(7):503-508
We study an evolutive model for electrical conduction in biological tissues, where the conductive intra-cellular and extracellular spaces are separated by insulating cell membranes. The mathematical scheme is an elliptic problem, with dynamical boundary conditions on the cell membranes. The problem is set in a finely mixed periodic medium. We show that the homogenization limit u0 of the electric potential, obtained as the period of the microscopic structure approaches zero, solves the equation where σ0>0 and the matrices A0, A1 depend on geometric and material properties, while the vector function keeps trace of the initial data of the original problem. Memory effects explicitly appear here, making this elliptic equation of non standard type. To cite this article: M. Amar et al., C. R. Mecanique 331 (2003). 相似文献
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Two pragmatic boundary value and eigenvalue problems of the Emden-Fowler equation and eu are studied using the simple one parameter group properties. In all cases boundary value problems are converted into initial value problems using the property of the invariance group. With an eigenvalue problem is detailed and calculations presented. 相似文献
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Isothermal and non-isothermal flow rate-pressure drop data in turbulent flow through smooth pipes have been obtained for non-Newtonian fluids, including aqueous solutions of polymers and aqueous suspensions of titanium dioxide. It has been found that the friction factor, f, is a function of a new form of Reynolds number, ReB, based on the parameters A, x and w of Bowen's correlation, viz. where τw is the wall shear strees, ?u the mean velocity, D the pipe diameter; A, x and w are experimentally derived parameters which characterise the fluid. 相似文献
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Tyn Myint-U 《International Journal of Non》1977,12(1):33-36
A class of complete integrals of the plane eikonal equation for harmonic u(x,y) is determined by using complex variables. The case in which z = 0 is a singular point of the analytic function whose real part is log f is also treated. Illustrative examples are given. 相似文献
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We study the initial boundary value problem for the reaction–diffusion equation, in a bounded domain with periodic microstructure , where aε(x) is of order 1 in and κ(ε) in with κ(ε)→0 as ε→0. Combining the method of two-scale convergence and the variational homogenization we obtain effective models which depend on the parameter θ=limε→0κ(ε)/ε2. In the case of strictly positive finite θ the effective problem is nonlocal in time that corresponds to the memory effect. To cite this article: L. Pankratov et al., C. R. Mecanique 331 (2003). 相似文献
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Turbulent deposition of particles from two-phase flow onto the smooth wall of a tube has been studied theoretically and experimentally. A model is proposed for the deposition motion of large particles based on turbulent diffusion in the core followed by a free flight towards the wall. The theory shows that within the Stokes regime, the dimensionless deposition velocity * depends on Re and only, where u* is the friction velocity, Re is the tube Reynolds number and is the dimensionless particle relaxation time. Deposition data are obtained for air-water droplet flow through a 12.7-mm i.d. acrylic tubing at and 94,600. The proposed theory satisfactorily describes the existing deposition data as well as present measurements, covering a wide range of Re and . 相似文献
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A. Povzner 《International Journal of Non》1974,9(4):279-323
Methods have been considered for deriving asymptotical formulas for the systems of the type by constructing an analog of the Schrödinger perturbation theory of the linear operator These methods can be extended to some classes of partial differential equations, in particular, to Whitham's non-linear theory. 相似文献
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