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1.
We consider a boundary-value problem for the second-order elliptic differential operator with rapidly oscillating coefficients
in a domain Ω
ε
that is ε-periodically perforated by small holes. The holes are split into two ε-periodic sets depending on the boundary interaction via their boundary surfaces. Therefore, two different nonlinear boundary
conditions σ
ε
(u
ε
) + εκ
m
(u
ε
) = εg
ε
(m)
, m = 1, 2, are given on the corresponding boundaries of the small holes. The asymptotic analysis of this problem is performed as ε → 0, namely, the convergence theorem for both the solution and the energy integral is proved without using an extension operator,
asymptotic approximations for the solution and the energy integral are constructed, and the corresponding approximation error
estimates are obtained. 相似文献
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6.
In this article, we study the homogenization of the family of parabolic equations over periodically perforated domains
. Here, Ωɛ
= ΩS
ε
is a periodically perforated domain andd
ε
is a sequence of positive numbers which goes to zero. We obtain the homogenized equation. The homogenization of the equations
on a fixed domain and also the case of perforated domain with Neumann boundary condition was studied by the authors. The homogenization
for a fixed domain and
has been done by Jian. We also obtain certain corrector results to improve the weak convergence. 相似文献
7.
In this article, we study the homogenization of the family of parabolic equations over periodically perforated domains
. Here, Ωɛ=ΩS
ɛ is a periodically perforated domain. We obtain the homogenized equation and corrector results. The homogenization of the
equations on a fixed domain was studied by the authors [15]. The homogenization for a fixed domain and
has been done by Jian [11]. 相似文献
8.
Galerkin methods for a semilinear parabolic problem with nonlocal boundary conditions 总被引:1,自引:0,他引:1
We formulate and analyze a Crank-Nicolson finite element Galerkin method and an algebraically-linear extrapolated Crank-Nicolson method for the numerical solution of a semilinear parabolic problem with nonlocal boundary conditions. For each method, optimal error estimates are derived in the maximum norm.Dedicated to Professor J. Crank on the occasion of his 80th birthdaySupported in part by the National Science Foundation grant CCR-9403461.Supported in part by project DGICYT PB95-0711. 相似文献
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10.
《Applied Mathematics Letters》2003,16(4):543-549
This paper deals with the blow-up rate estimates of positive solutions for semilinear parabolic systems with nonlinear boundary conditions. The upper and lower bounds of blow-up rates are obtained. 相似文献
11.
12.
In this paper, we deal with a class of semilinear parabolic problems related to a Hardy inequality with singular weight at the boundary.
More precisely, we consider the problemwhere Ω is a bounded regular domain of \({\mathbbm{R}^N}\), \({d(x)=\text{dist}(x,\partial\Omega)}\), \({p > 0}\), and \({\lambda > 0}\) is a positive constant.
$$\left\{\begin{array}{l@{\quad}l}u_t-\Delta u=\lambda \frac{u^p}{d^2}&\text{ in }\,\Omega_{T}\equiv\Omega \times (0,T), \\u>0 &\text{ in }\,{\Omega_T}, \\u(x,0)=u_0(x)>0 &\text{ in }\,\Omega, \\u=0 &\text{ on }\partial \Omega \times (0,T),\end{array}\right.$$
(P)
We prove that Moreover, we consider also the concave–convex-related case.
相似文献
- 1.If \({0 < p < 1}\), then (P) has no positive very weak solution.
- 2.If \({p=1}\), then (P) has a positive very weak solution under additional hypotheses on \({\lambda}\) and \({u_0}\).
- 3.If \({p > 1}\), then, for all \({\lambda > 0}\), the problem (P) has a positive very weak solution under suitable hypothesis on \({u_0}\).
13.
14.
Summary When two immiscible fluids in a porous medium are in contact with one another, an interface is formed and the movement of
the fluids results in a free boundary problem for determining the location of the interface along with the pressure distribution
throughout the medium. The pressure satisfies a nonlinear parabolic partial differential equation on each side of the interface
while the pressure and the volumetric velocity are continuous across the interface. The movement of the interface is related
to the pressure through Darcy’s law. Two kinds of boundary conditions are considered. In Part I the pressure is prescribed
on the known boundary. A weak formulation of the classical problem is obtained and the existence of a weak solution is demonstrated
as a limit of a sequence of classical solutions to certain parabolic boundary value problems. In Part II the same analysis
is carried out when the flux is specified on the known boundary, employing special techniques to obtain the uniform parabolicity
of the sequence of approximating problems.
Entrata in Redazione il 29 novembre 1975.
This research was supported in part by the National Science Foundation, the Senior Fellowship Program of the North Atlantic
Treaty Organization, the Italian Consiglio Nazionale delle Ricerche, and the Texas Tech. University. 相似文献
15.
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17.
This paper concerns with the problem of how to running an insurance company to maximize his total discounted expected dividends. In our model, the dividend rate is limited in and the company is allowed to transfer any proportion of risk by reinsuring. So there are two strategies which we call dividend strategy and reinsurance strategy. The objective function and the corresponding optimal two strategies are the solution and the two free boundaries of the following Barenblatt parabolic equation under certain boundary conditions on an angular domain The main effort is to analyze the properties of the solution and the free boundaries to show the optimal decision for the insurance company. 相似文献
18.
19.
This paper deals with asymptotic analysis of a parabolic system with inner absorptions and coupled nonlinear boundary fluxes.
Three simultaneous blow-up rates are established under different dominations of nonlinearities, and simply represented in
a characteristic algebraic system introduced for the problem. In particular, it is observed that two of the multiple blow-up
rates are absorption-related. This is substantially different from those for nonlinear parabolic problems with absorptions
in all the previous literature, where the blow-up rates were known as absorptionindependent. The results of the paper rely
on the scaling method with a complete classification for the nonlinear parameters of the model. The first example of absorption-related
blow-up rates was recently proposed by the authors for a coupled parabolic system with mixed type nonlinearities. The present
paper shows that the newly observed phenomena of absorptionrelated blow-up rates should be due to the coupling mechanism,
rather than the mixed type nonlinearities.
相似文献
20.
Lech Zarȩba 《NoDEA : Nonlinear Differential Equations and Applications》2009,16(4):445-467
In this paper we consider the mixed problem for the equation u
tt
+ A
1
u + A
2(u
t
) + g(u
t
) = f(x, t) in unbounded domain, where A
1 is a linear elliptic operator of the fourth order and A
2 is a nonlinear elliptic operator of the second order. Under natural assumptions on the equation coefficients and f we proof existence of a solution. This result contains, as a special case, some of known before theorems of existence. Essentially,
in difference up to previous results we prove theorems of existence without the additional assumption on behavior of solution
at infinity.
相似文献