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In composite material, the stress may be arbitrarily large in the narrow region between two close-to-touching hard inclusions. The stress is represented by the gradient of a solution to the Lam\'{e} system of linear elasticity. The aim of…

Analysis of PDEs · Mathematics 2018-11-09 Haigang Li

In this paper, we investigate the gradient estimates for solutions to the perfect conductivity problem with two closely spaced perfect conductors embedded in a homogeneous matrix, modeled by $p$-Laplacian elliptic equations. We first prove…

Analysis of PDEs · Mathematics 2026-01-15 Hongjie Dong , Longjuan Xu

We study the insulated conductivity problem with closely spaced insulators embedded in a homogeneous matrix where the current-electric field relation is the power law $J = |E|^{p-2}E$. The gradient of solutions may blow up as $\varepsilon$,…

Analysis of PDEs · Mathematics 2023-05-12 Hongjie Dong , Zhuolun Yang , Hanye Zhu

In high-contrast composites, the electric (or stress) field may exhibit significant amplification in the narrow region between inclusions. The behavior of the solution depends on the distance $\epsilon$ between the inclusions, which tends…

Analysis of PDEs · Mathematics 2026-04-28 Linjie Ma

When perfectly conducting or insulating inclusions are closely located, stress which is the gradient of the solution to the conductivity equation can be arbitrarily large as the distance between two inclusions tends to zero. It is important…

Analysis of PDEs · Mathematics 2012-06-12 Habib Ammari , Giulio Ciraolo , Hyeonbae Kang , Hyundae Lee , KiHyun Yun

In this paper, we establish the estimates for the gradient and the second-order partial derivatives for the Stokes flow in the presence of two closely located strictly convex inclusions in dimension three. Moreover, the blow-up rate of the…

Analysis of PDEs · Mathematics 2023-10-17 Haigang Li , Longjuan Xu

This paper estimates the blow-up time for the heat equation $u_t=\Delta u$ with a local nonlinear Neumann boundary condition: The normal derivative $\partial u/\partial n=u^{q}$ on $\Gamma_{1}$, one piece of the boundary, while on the rest…

Analysis of PDEs · Mathematics 2016-06-08 Xin Yang , Zhengfang Zhou

The purpose of this paper is to set out optimal gradient estimates for solutions to the isotropic conductivity problem in the presence of adjacent conductivity inclusions as the distance between the inclusions goes to zero and their…

Analysis of PDEs · Mathematics 2007-05-23 H. Ammari , H. Kang , H. Lee , J. Lee , M. Lim

We consider the isentropic compressible Euler equations in the half-line which govern the motion of gaseous fluids in contact with stationary vacuum boundary. We construct a large class of solutions that are initially smooth and…

Analysis of PDEs · Mathematics 2026-05-04 Juhi Jang , Jiaqi Liu , Nader Masmoudi

In this paper, we derive the pointwise upper bounds and lower bounds on the gradients of solutions to the Lam\'{e} systems with partially infinite coefficients as the surface of discontinuity of the coefficients of the system is located…

Analysis of PDEs · Mathematics 2017-05-17 Jiguang Bao , Hongjie Ju , Haigang Li

This paper is concerned with weak solutions of the degenerate viscous Hamilton-Jacobi equation $$\partial_t u-\Delta_p u=|\nabla u|^q,$$ with Dirichlet boundary conditions in a bounded domain $\Omega\subset\mathbb{R}^N$, where $p>2$ and…

Analysis of PDEs · Mathematics 2012-02-08 Amal Attouchi

In this paper, we use the maximum principle to get the gradient estimate for the solutions of the prescribed mean curvature equation with Neumann boundary value problem, which gives a positive answer for the question raised by Lieberman…

Analysis of PDEs · Mathematics 2016-06-23 Xi-Nan Ma , Jinju Xu

We study the gradient and higher order derivative estimates for the transmission problem in the presence of closely located inclusions. We show that in two dimensions, when relative conductivities of circular inclusions have different…

Analysis of PDEs · Mathematics 2023-06-13 Hongjie Dong , Zhuolun Yang

By tailoring the geometry of the upper boundary in turbulent Rayleigh-B\'enard convection we manipulate the boundary layer -- interior flow interaction, and examine the heat transport using the Lattice Boltzmann method. For fixed amplitude…

Fluid Dynamics · Physics 2015-09-14 Srikanth Toppaladoddi , Sauro Succi , John S. Wettlaufer

It is interesting to study the stress concentration between two adjacent stiff inclusions in composite materials, which can be modeled by the Lam\'e system with partially infinite coefficients. To overcome the difficulty from the lack of…

Analysis of PDEs · Mathematics 2018-02-06 Yuanyuan Hou , Hongjie Ju , Haigang Li

When inclusions with extreme conductivity (insulator or perfect conductor) are closely located, the gradient of the solution to the conductivity equation can be arbitrarily large. And computation of the gradient is extremely challenging due…

Analysis of PDEs · Mathematics 2015-03-19 Hyeonbae Kang , Mikyoung Lim , KiHyun Yun

In this paper, the insulated conductivity model with two touching or close-to-touching inclusions is considered in $\mathbb{R}^{d}$ with $d\geq3$. We establish the pointwise upper bounds on the gradient of the solution for the generalized…

Analysis of PDEs · Mathematics 2022-07-26 Zhiwen Zhao

This paper is concerned with finite element error estimates for Neumann boundary control problems posed on convex and polyhedral domains. Different discretization concepts are considered and for each optimal discretization error estimates…

Numerical Analysis · Mathematics 2024-09-18 Johannes Pfefferer , Boris Vexler

We establish the first complete classification of finite-time blow-up scenarios for strong solutions to the three-dimensional incompressible Euler equations with surface tension in a bounded domain possessing a closed, moving free boundary.…

Analysis of PDEs · Mathematics 2025-07-15 Chengchun Hao , Tao Luo , Siqi Yang

We prove a Li-Yau gradient estimate for positive solutions to the heat equation, with Neumann boundary conditions, on a compact Riemannian submanifold with boundary ${\bf M}^n\subseteq {\bf N}^n$, satisfying the integral Ricci curvature…

Differential Geometry · Mathematics 2018-04-13 Xavier Ramos Olivé