共查询到18条相似文献,搜索用时 390 毫秒
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《数学的实践与认识》2020,(17)
对半无限柱体区域中的多孔介质中的两种相互作用的B rinkman-Forchheimer流与Darcy流进行研究.通过构造一个加权的能量表达式,得到该表达式所满足的微分不等式,然后通过求解该不等式得到解的空间衰减估计结果.这个结果可看作圣维南原则的一个应用. 相似文献
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研究了高维空间上具有空变系数的半线性反应-扩散抛物系统在非线性边界条件下的解的爆破问题.构造了一个能量表达式,运用微分不等式的方法,得到了该能量方程所满足的微分不等式.然后通过积分导出了解的爆破时间下界的估计. 相似文献
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就变截面的半无限圆柱体,当横向边界值为0时,研究半线性抛物线型方程的初边值问题解的空间衰减.对其解的一个L2p横截面量,导出的2阶微分不等式表明,空间衰减呈D(exp{-z2/[4(t+t0)]}).同时导出了引起增长或衰减的1阶微分不等式.在爆破空间中得到增长情况下的上界,当衰减情况时,根据已知的数据,得到总能量的上界. 相似文献
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该文将讨论一类由半线性发展方程和广义变分不等式所组成的微分变分不等式系统.首先,考虑广义变分不等式解集的性质.其次,通过利用不动点定理和半群理论证明了微分变分不等式系统解的存在性.另外,通过运用稠定性结果证明了微分变分不等式系统的Bang-Bang准则.同时,运用一个障碍型抛物-椭圆系统来检验该文的主要结果. 相似文献
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退化时滞中立型微分系统解的存在唯一性及指数估计 总被引:1,自引:1,他引:0
本文主要讨论退化时滞中立型微分系统解的存在唯一性及指数估计问题.通过定义正则矩阵对讨论退化时滞中立型微分系统解的存在唯一性.再定义基解矩阵以及Laplace变换,给出该系统的通解表达式,最后利用通解表达式和Gronwall-Bellman积分不等式给出该系统解的指数估计及解的精确指数界限. 相似文献
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In this paper,the 16-parameter nonconforming tetrahedral element which has an energy-orthogonal shape function space is presented for the discretization of fourth order elliptic partial differential operators in three spatial dimensions.The newly constructed element is proved to be convergent for a model biharmonic equation. 相似文献
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Gaurav Dwivedi Jagmohan Tyagi 《NoDEA : Nonlinear Differential Equations and Applications》2016,23(2):10
In this paper, we establish a nonlinear analogue of Picone’s identity for biharmonic operators on Heisenberg group. As an applications of Picone’s identity, we obtain Hardy-Rellich type inequality, Morse index, Caccioppoli inequality, Picone inequality for biharmonic operators on Heisenberg group. 相似文献
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研究了非线性抛物方程在非线性边界条件下的解的爆破问题,通过构造一个能量表达式,运用微分不等式的方法,得到该能量表达式所满足的微分不等式,然后通过积分得到当爆破发生时解在非线性边界条件下的爆破时间的下界. 相似文献
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Qiaoling Wang 《Journal of Functional Analysis》2007,245(1):334-352
In this paper we consider eigenvalues of the Dirichlet biharmonic operator on compact Riemannian manifolds with boundary (possibly empty) and prove a general inequality for them. By using this inequality, we study eigenvalues of the Dirichlet biharmonic operator on compact domains in a Euclidean space or a minimal submanifold of it and a unit sphere. We obtain universal bounds on the (k+1)th eigenvalue on such objects in terms of the first k eigenvalues independent of the domains. The estimate for the (k+1)th eigenvalue of bounded domains in a Euclidean space improves an important inequality obtained recently by Cheng and Yang. 相似文献
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We deal with the system describing moderately large deflections of thin viscoelastic plates with an inner obstacle. In the case of a long memory the system consists of an integro-differential 4th order variational inequality for the deflection and an equation with a biharmonic left-hand side and an integro-differential right-hand side for the Airy stress function. The existence of a solution in a special case of the Dirichlet-Prony series is verified by transforming the problem into a sequence of stationary variational inequalities of von Karman type. We derive conditions for applying the Banach fixed point theorem enabling us to solve the biharmonic variational inequalities for each time step. 相似文献
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We show that a conformal mapping between Riemannian manifolds of the same dimension n ≥ 3 is biharmonic if and only if the gradient of its dilation satisfies a certain second-order elliptic partial differential
equation. On an Einstein manifold solutions can be generated from isoparametric functions. We characterise those semi-conformal
submersions that are biharmonic in terms of their dilation and the fibre mean curvature vector field.
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In this paper, under an improved Hardy-Rellich's inequality, we study the existence of multiple and sign-changing solutions for a biharmonic equation in unbounded domain by the minimax method and linking theorem. 相似文献