Existence of boundary value problems for TFD equation in quantum mechanics

ＩｎｔｒｏｄｕｃｔｉｏｎＴｏｓｔｕｄｙｐｏｔｅｎｔｉａｌｓａｎｄｃｈａｒｇｅｄｅｎｓｉｔｉｅｓｏｆａｔｏｍｓｉｎｑｕａｎｔｕｍｍｅｃｈａｎｉｃｓ,ｉｔｉｓｓｕｍｍｅｄｕｐａｓｓｏｌｖｉｎｇＳｃｈｒｄｉｎｇｅｒｅｑｕａｔｉｏｎｗｉｔｈｗａｖｅｆｕｎｃｔｉｏｎψ(ｒ):-122 Ｖ(ｒ)ψ(ｒ)=Ｅψ(ｒ),(1)｜ψ(0)｜<Ｍ,｜ψ(ｒ)｜｜ｒ｜→∞=0(2)ａｎｄｔｈｅｃｒｕｘｏｆｔｈｅｍａｔｔｅｒｉｓｇｏｉｎｇｔｏｄｅｔｅｒｍｉｎｅＶ(ｒ).Ｔｈｕｓ,ｔｈｅｋｎｏｗｎＴｈｏｍａｓ＿Ｆｅｒｍｉｅｑｕａｔｉｏｎ,ｏｂｔａｉｎｅｄｉ…     

On the boundary value problems for ordinary differential equations with turning points

In this paper,we consider the boundary value problems of the formsy″-f(x,ε)y′ g(x,ε)=0 (-a≤x≤b,0≤ε《1 )y(-a)=a,y(b)=βwhere f(x,0)has several and multiple zeros on the interval[-a,b].The conditions forexhibiting boundary and interior layers are given,and the corresponding asymptoticexpansions of solutions are constructed.     

On the derivation of well posed boundary value problems in structural mechanics

The paper starts with a discussion of a number of published boundary value problems in structural mechanics, whose intuitive formulation led to incorrect boundary or matching conditions. It is then shown on three examples, using variational methods, how to obtain well posed formulations for problems of this type. For uniformity of presentation, all examples deal with continuously supported beams. The first two examples exhibit boundary and matching points whose position is fixed along the beam axis. In the third example it is shown how to use the method of variational calculus for a variable end point to formulate structural problems with variable matching points. This is demonstrated on the problem of a beam which rests on, but is not attached to, a Pasternak base; thus where parts of the beam may lift off the base. Each example concludes with a comparison and discussion of related formulations published in the literature.     

On the approximate solution of elliptic,self adjoint boundary value problems

Summary Integral representations for the solutions to linear elliptic self adjoint boundary value problems are derived in terms of two functions which are generalisations of the single and double layer potentials used in the theory of harmonic functions. The generalised potentials are constructed in terms of a fundamental solution which is an approximation to the exact kernel of the boundary value problem in question. The representations so obtained are shown to provide a basis from which strict approximations to the solutions of boundary value problems can be developed. In particular the structure of the integral equation representing the given boundary value problem is precisely determined.     

On the boundary value problems for a class of ordinary differential equations with turning points

In this paper we study the boundary value problems for a class of ordinary differential equations with turning points by the method of multiple scales. The paradox in [1] and the variational approach in [2] are avoided. The uniformly valid asymptotic approximations of solutions have been constructed. We also study the case which does not exhibit resonance.     

Laplace transform method in boundary value problems for the Helmholtz equation

The purpose of this present note is to obtain boundary integral equation formulations of boundary value problems for the two-dimensional Helmholtz equation. The intergral equations are derived using the Laplace transform method.     

On the displacement potential solution of plane problems of structural mechanics with mixed boundary conditions

The present paper describes the advancement of displacement potential approach in relation to solution of plane problems of structural mechanics with mixed mode of boundary conditions. Both the conditions of the plane stress and the plane strain are considered for analyzing the displacement and stress fields of the structural problem. Using the finite difference technique based on the present displacement potential approach for the case of the plane stress and the plane strain conditions, firstly an elastic cantilever beam subjected to a pure shear at its tip is solved and these two solutions (plane stress and plane strain) are compared with Timoshenko and Goodier cantilever beam bending solutions (Theory of elasticity, 2nd edn. McGraw-Hill, New York, 1951); secondly the above-mentioned displacement potential approach for the case of the plane stress and the plane strain conditions are applied to solve a one-end fixed square plate subjected to a combined loading at its tip. Effects of plane stress and plane strain on the elastic field of the plate are discussed in a comparative fashion. Limitations of Timoshenko and Goodier cantilever beam bending solutions (Theory of elasticity, 2nd edn. McGraw-Hill, New York, 1951) over the displacement potential approach for the case of the plane stress and the plane strain conditions are not only discussed but also the superiority of the present displacement potential approach for the case of the plane stress and the plane strain conditions are reflected in the present research work.     

Periodic boundary value problems for first-order integro-differential equations of mixed type

ＩｎｔｒｏｄｕｃｔｉｏｎＣｏｎｓｉｄｅｒｔｈｅｆｏｌｌｏｗｉｎｇｐｅｒｉｏｄｉｃｂｏｕｎｄａｒｙｖａｌｕｅｐｒｏｂｌｅｍ(ＰＢＶＰ,ｆｏｒｓｈｏｒｔ)ｆｏｒｆｉｒｓｔ＿ｏｒｄｅｒｉｎｔｅｇｒｏ＿ｄｉｆｆｅｒｅｎｔｉａｌｅｑｕａｔｉｏｎｏｆｍｉｘｅｄｔｙｐｅｕ′=ｆ(ｔ,ｕ,Ｔ1ｕ,Ｔ2ｕ)　　(ａ.ｅ.ｔ∈Ｉ),(1)ｕ(0)=ｕ(2π),(2)ｗｈｅｒｅＩ=[0,2π],ｆｓａｔｉｓｆｉｅｓＣａｒａｔｈｅｏｄｏｒｙ’ｓｃｏｎｄｉｔｉｏｎｓ,Ｔ1ｉｓａＶｏｌｔｅｒｒａｉｎｔｅｇｒａｌｏｐｅｒａｔｏｒ,Ｔ2ｉｓａＦｒｅｄｈｏｌｍｉｎｔｅ…     

Existence of solutions for periodic boundary value problems for second-order integro-differential equations

ＩｎｔｒｏｄｕｃｔｉｏｎＬｅｔ(Ｅ,｜·｜)ｂｅａｒｅａｌＢａｎａｃｈｓｐａｃｅｗｉｔｈａｐａｒｔｉａｌｏｒｄｅｒｉｎｔｒｏｄｕｃｅｄｂｙａｒｅｇｕｌａｒｃｏｎｅＫｏｆＥ.Ｉｎｔｈｉｓｐａｐｅｒ,ｔｈｅｅｘｉｓｔｅｎｃｅｏｆｓｏｌｕｔｉｏｎｓｏｆｔｈｅｆｏｌｌｏｗｉｎｇｐｅｒｉｏｄｉｃｂｏｕｎｄａｒｙｖａｌｕｅｐｒｏｂｌｅｍｓ(ＰＢＶＰ)ｗｉｌｌｂｅｉｎｖｅｓｔｉｇａｔｅｄ:　　(Ⅰ)ｕ″=ｆ(ｔ,ｕ,Ｔｕ)　ａ.ｅ.ｔ∈Ｊ,ｕ(0)=ｕ(ａ),ｕ′(0)=ｕ′(ａ),ｗｈｅｒｅｆ∈Ｃ(Ｊ×Ｅ×Ｅ,Ｅ),Ｊ=[0,ａ](ａ>0),ａｎｄ(Ｔ…     

SINGULARLY PERTURBED BOUNDARY VALUE PROBLEMS FOR SEMI-LINEAR RETARDED DIFFERENTIAL EQUATIONS WITH NONLINEAR BOUNDARY CONDITIONS

IntroductionInthispaper,westudiedakindofboundaryvalueproblems (BVPs)forsemi_linearretardeddifferentialequationwithnonlinearboundarycondition :　　　　εx″(t) =f(t,x(t) ,x(t-ε) ,ε) ,　　t∈(0 ,1 ) ,(1 )　　　　x(t) =φ(t,ε) ,　t∈[-ε0 ,0 ] ,h(x(1 ) ,x′(1 ) ,ε) =A(ε) ,(2 )whereε>0isasmallparameterandε0 isasufficientlysmallpositiveconstant.ThereweremanyresultsofstudyingonsingularlyperturbedboundaryvalueproblemforretardeddifferentialequationinRefs.[1～5] .Butthosestudiespossessedanesse…     

A boundary integral equation method for the solution of a class of crack problems

A boundary integral equation method for the solution of an important class of crack problems in elasticity is outlined. The method is applicable for deformations in which the crack faces remain in contact. Specific numerical examples are considered to illustrate the application of the method.     

INITIAL BOUNDARY VALUE PROBLEMS FOR A CLASS OF NONLINEAR INTEGRO－PARTIAL DIFFERENTIAL EQUATIONS

ＩＮＩＴＩＡＬＢＯＵＮＤＡＲＹＶＡＬＵＥＰＲＯＢＬＥＭＳＦＯＲＡＣＬＡＳＳＯＦＮＯＮＬＩＮＥＡＲＩＮＴＥＧＲＯ－ＰＡＲＴＩＡＬＤＩＦＦＥＲＥＮＴＩＡＬＥＱＵＡＴＩＯＮＳＣｕｉＳｈａｎｇ－ｂｉｎ（崔尚斌）（Ｄｅｐｔ．ｏｆＭａｔｈ．,ＬａｎｚｈｏｕＵｎｉ...     

ON THE EXISTENCE AND STABILITY OF SOLUTION FOR SEMI－HOMOGENEOUS BOUNDARY VALUE PROBLEM

ＯＮＴＨＥＥＸＩＳＴＥＮＣＥＡＮＤＳＴＡＢＩＬＩＴＹＯＦＳＯＬＵＴＩＯＮＦＯＲＳＥＭＩ－ＨＯＭＯＧＥＮＥＯＵＳＢＯＵＮＤＡＲＹＶＡＬＵＥＰＲＯＢＬＥＭＤｏｎｇＱｉｎｘｉ（董勤喜）;ＨｕａｎｇＸｉａｎｋａｉ（黄先开）（ＲｅｃｅｉｖｅｄＪｕｌｙ．４．１９...     

On the solution of nonlinear two-point boundary value problem

In this paper, a non-variational version of a max-min principle is proposed, andan existence and uniqueness result is obtained for the nonlinear two-point boundaryvalue problenl u"+g(t.u)=f(t),u(0)=u(2π)=0     

On the final boundary value problems in linear thermoelasticity

In the present study we derive some uniqueness criteria for solutions of the Cauchy problem for the standard equations of dynamical linear thermoelasticity backward in time. We use Lagrange-Brun identities combined with some differential inequalities in order to show that the final boundary value problem associated with the linear thermoelasticity backward in time has at most one solution in appropriate classes of displacement-temperature fields. The uniqueness results are obtained under the assumptions that the density mass and the specific heat are strictly positive and the conductivity tensor is positive definite.