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Forced periodic vibrations of an elastic system with elastico-plastic damping

Pavel Krejčí (1988)

Aplikace matematiky

We prove the existence and find necessary and sufficient conditions for the uniqueness of the time-periodic solution to the equations u t t - Δ x u ± F ( u ) = g ( x , t ) for an arbitrary (sufficiently smooth) periodic right-hand side g , where Δ x denotes the Laplace operator with respect to x Ω R N , N 1 , and F is the Ishlinskii hysteresis operator. For N = 2 this equation describes e.g. the vibrations of an elastic membrane in an elastico-plastic medium.

Free vibrations for the equation of a rectangular thin plate

Eduard Feireisl (1988)

Aplikace matematiky

In the paper, we deal with the equation of a rectangular thin plate with a simply supported boundary. The restoring force being an odd superlinear function of the vertical displacement, the existence of infinitely many nonzero time-periodic solutions is proved.

Galerkin approximations for nonlinear evolution inclusions

Shouchuan Hu, Nikolaos S. Papageorgiou (1994)

Commentationes Mathematicae Universitatis Carolinae

In this paper we study the convergence properties of the Galerkin approximations to a nonlinear, nonautonomous evolution inclusion and use them to determine the structural properties of the solution set and establish the existence of periodic solutions. An example of a multivalued parabolic p.d.ei̇s also worked out in detail.

Geometrical methods in hydrodynamics

Adrian Constantin (2001)

Journées équations aux dérivées partielles

We describe some recent results on a specific nonlinear hydrodynamical problem where the geometric approach gives insight into a variety of aspects.

Growth of Sobolev norms in the cubic defocusing nonlinear Schrödinger equation

Marcel Guardia, Vadim Kaloshin (2015)

Journal of the European Mathematical Society

We consider the cubic defocusing nonlinear Schrödinger equation in the two dimensional torus. Fix s > 1 . Recently Colliander, Keel, Staffilani, Tao and Takaoka proved the existence of solutions with s -Sobolev norm growing in time. We establish the existence of solutions with polynomial time estimates. More exactly, there is c > 0 such that for any 𝒦 1 we find a solution u and a time T such that u ( T ) H s 𝒦 u ( 0 ) H s . Moreover, the time T satisfies the polynomial bound 0 < T < 𝒦 C .

Homogenization of a carcinogenesis model with different scalings with the homogenization parameter

Isabell Graf, Malte A. Peter (2014)

Mathematica Bohemica

In the context of periodic homogenization based on two-scale convergence, we homogenize a linear system of four coupled reaction-diffusion equations, two of which are defined on a manifold. The system describes the most important subprocesses modeling the carcinogenesis of a human cell caused by Benzo-[a]-pyrene molecules. These molecules are activated to carcinogens in a series of chemical reactions at the surface of the endoplasmic reticulum, which constitutes a fine structure inside the cell....

Indices of Orlicz spaces and some applications

Alberto Fiorenza, Miroslav Krbec (1997)

Commentationes Mathematicae Universitatis Carolinae

We study connections between the Boyd indices in Orlicz spaces and the growth conditions frequently met in various applications, for instance, in the regularity theory of variational integrals with non-standard growth. We develop a truncation method for computation of the indices and we also give characterizations of them in terms of the growth exponents and of the Jensen means. Applications concern variational integrals and extrapolation of integral operators.

Currently displaying 81 – 100 of 279