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71.
A two-scale model of ion transfer in a porous medium is obtained for one-dimensional horizontal flows under the action of
a pressure gradient and an external electric field by the method of homogenization. Steady equations of electroosmotic flows
in flat horizontal nano-sized slits separated by thin dielectric partitions are averaged over a small-scale variable. The
resultant macroequations include Poisson’s equation for the vertical component of the electric field and Onsager’s relations
between flows and forces. The total horizontal flow rate of the fluid is found to depend linearly on the pressure gradient
and external electric field, and the coefficients in this linear relation are calculated with the use of microequations.
__________
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 4, pp. 162–173, July–August, 2008. 相似文献
72.
本文研究统计假设检验问题中的渐近展开和功效损失,给出一阶渐近展开,二阶效率和功效损失,并且研究了建立在L-,R-,U-统计量及组合L-统计量上的检验问题。 相似文献
73.
We consider in this paper random flights in ℝ
d
performed by a particle changing direction of motion at Poisson times. Directions are uniformly distributed on hyperspheres
S
1
d
. We obtain the conditional characteristic function of the position of the particle after n changes of direction. From this characteristic function we extract the conditional distributions in terms of (n+1)−fold integrals of products of Bessel functions. These integrals can be worked out in simple terms for spaces of dimension
d=2 and d=4. In these two cases also the unconditional distribution is determined in explicit form. Some distributions connected with
random flights in ℝ3 are discussed and in some special cases are analyzed in full detail. We point out that a strict connection between these
types of motions with infinite directions and the equation of damped waves holds only for d=2.
Related motions with random velocity in spaces of lower dimension are analyzed and their distributions derived. 相似文献
74.
Árpád Baricz 《Journal of Mathematical Analysis and Applications》2007,327(2):1202-1213
This paper is motivated by an open problem of Anderson, Vamanamurthy, and Vuorinen. We prove a chain of inequalities for hypergeometric functions, generalized and normalized Bessel functions, Kummer functions and for some general power series. Some particular cases and refinements are given. 相似文献
75.
The fourth-order ordinary differential equation that defines the self-similar solutions of the Kaup—Kupershmidt and Sawada—Kotera
equations is studied. This equation belongs to the class of fourth-order analogues of the Painlevé equations. All the power
and non-power asymptotic forms and expansions near points z = 0, z = ∞ and near an arbitrary point z = z
0 are found by means of power geometry methods. The exponential additions to the solutions of the studied equation are also
determined.
相似文献
76.
I. Kátai 《Lithuanian Mathematical Journal》2007,47(1):24-31
We characterize the q-multiplicative functions which belong to
or
= the set of uniformly summable functions on the set of primes.
Dedicated to Professor Jonas Kubilius on his 85th anniversary
Published in Lietuvos Matematikos Rinkinys, Vol. 47, No. 1, pp. 29–38, January–March, 2007. 相似文献
77.
Mochi M. Pacelli G. Recchioni M. C. Zirilli F. 《Journal of Optimization Theory and Applications》1999,100(1):29-57
In this paper, we consider an inverse problem for a class of two-dimensional diffusion equations with piecewise constant coefficients. This problem is studied using an explicit formula for the relevant spectral measures and an asymptotic expansion of the solution of the diffusion equations. A numerical method that reduces the inverse problem to a sequence of nonlinear least-square problems is proposed and tested on synthetic data. 相似文献
78.
José Luis López 《Journal of Mathematical Analysis and Applications》2011,377(1):30-42
Asymptotic expansions are given for large values of n of the generalized Bessel polynomials . The analysis is based on integrals that follow from the generating functions of the polynomials. A new simple expansion is given that is valid outside a compact neighborhood of the origin in the z-plane. New forms of expansions in terms of elementary functions valid in sectors not containing the turning points z=±i/n are derived, and a new expansion in terms of modified Bessel functions is given. Earlier asymptotic expansions of the generalized Bessel polynomials by Wong and Zhang (1997) and Dunster (2001) are discussed. 相似文献
79.
Nonlinear torsional waves propagating along an infinite isotropic cylinder are considered. The hyperelasticity of the cylinder is described by the Murnaghan potential. An approximate analytical solution of the problem is obtained. The evolution of the initial waveprofile in cylinders made of composite materials reinforced with microscale particles is simulated numerically. It is shown that the approximation used to describe the variation in the amplitude inward the cylinder is quite accurate. Three-dimensional plots of evolution are presented __________ Translated from Prikladnaya Mekhanika, Vol. 44, No. 3, pp. 75–85, March 2008. 相似文献
80.
Luis O. Silva Julio H. Toloza 《Journal of Mathematical Analysis and Applications》2008,345(2):661-669
Sampling theory concerns the problem of reconstruction of functions from the knowledge of their values at some discrete set of points. In this paper we derive an orthogonal sampling theory and associated Lagrange interpolation formulae from a family of bounded rank-one perturbations of a self-adjoint operator that has only discrete spectrum of multiplicity one. 相似文献