摘要:

AbstractAn integral representation for the solutions of the interior and exterior homogeneous mixed problems on a regular bounded open set inR3is given in terms of a potential of simple layer on the Dirichlet data and of double layer on the Neumann data. A coercive non‐symmetric bilinear form is provided. Singular finite elements containing the first terms of the assymptotic expansion of the singularity are built and error estimates for the surface distributions are give

ISSN:0170-4214    

DOI:10.1002/mma.1670030132

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractThe existence of a unique solution to Maxwell's equations defined in an exterior domain with impedance boundary condition is established for all frequencies. This is accomplished by reducing this problem to that of solving a system of singular integral equations and then regularizing this system such that the Riesz theory is applicable. We also consider the inverse problem in which it is desired to determine the impedance from a knowledge of the far field pattern. By restricting the impedance to lie a priori in a compact set results are obtained on the existence, uniqueness, and stability of the solution to this inverse scattering problem.

ISSN:0170-4214    

DOI:10.1002/mma.1670030133

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractThe purpose of this paper is to give a systematic analysis for the linear energy dependent diffusion system in reactor dynamics, taking into consideration of delayed neutrons. This analysis includes the existence of a unique positive solution for the time dependent system, the asymptotic behaviour of the solution ast→ ∞, the stability and instability of steady‐state solutions, and the existence and uniqueness of a steady‐state solution for the time‐independent system. Using the notion of upper and lower solution, we establish some threshold conditions for insuring the asymptotic behaviour of the solution and the stability and the instability of any given unperturbed solution, including steady‐state solution. In fact, these conditions characterize the stability and the instability property of the solution, and yield a bifurcation result in terms of either the size of the diffusion domain or the physical parameters of the diffusion medium. We also discuss the case without the effect of delay

ISSN:0170-4214    

DOI:10.1002/mma.1670030134

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractThe approximation sequence for the scattering state is constructed by the solutions for the reduced wave equations in some bounded domains with radiation conditions at their boundary. The corresponding discrete approximation is also considered by the Bubnov‐Galerkin metho

ISSN:0170-4214    

DOI:10.1002/mma.1670030135

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractIn this paper the limiting equations approach is applied to study the stability properties with respect to a part of the state variables for nonautonomous dynamical systems. Sufficient conditions are given for uniform asymptotic eventual strongly partial stability and for uniform asymptotic partial stability. An application of the results is given.

ISSN:0170-4214    

DOI:10.1002/mma.1670030136

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractMethods using the theory of distributions and Hilbert space operators have been very powerful in the past to achieve uniqueness and existence results for Maxwell's equations. In this paper conditions are given when such abstract “Hilbert space”‐solutions represent differentiable “regular” functions which satisfy Maxwell's equations, boundary conditions, and transmission conditions in the classi

ISSN:0170-4214    

DOI:10.1002/mma.1670030137

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

The relaxation drag of a slender profile or profile arrangement in plane, steady, relaxing subsonic gas flow is studied. Especially, the question is discussed which shapes the profiles must have in order to minimize the relaxation drag. These optimization problems lead to a number of singular integral equations of first kind, one of which is solved as an example with the help of a suitable chosen ansatz.

ISSN:0170-4214    

DOI:10.1002/mma.1670030138

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractSpherical spline functions are introduced by use of Green's surface functions with respect to the (Laplace‐)Beltrami operator of the (unit) sphere. Natural (spherical) spline functions are used to interpolate data discretely given on the sphere. A method is presented that allows the smoothing of irregularities in measured values or experimental data. Extensions of Peano's theorem and Sard's theory of best approximation to the spherical case are given by integral formulas. Schoenberg's theorem is transcribed into spherical nomenclatur

ISSN:0170-4214    

DOI:10.1002/mma.1670030139

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

ISSN:0170-4214    

DOI:10.1002/mma.1670030101

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY