2025-12-16 2024, Volume 37 Issue 4

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  • research-article
    Xueli SONG , Xiaofeng LI , Xi DENG , Biaoming QIAO

    We consider the uniform attractors of a 3D non-autonomous Brinkman- Forchheimer equation with a singularly oscillating force

    $\frac{\partial u}{\partial t}-\gamma \Delta u+a u+b|u| u+c|u|^{2} u+\nabla p=f_{0}(x, t)+\varepsilon^{-\rho} f_{1}\left(x, \frac{t}{\varepsilon}\right),$

    for ρ∈[0,1) and ε>0, and the averaged equation (corresponding to the limiting case $\epsilon =0$)

    $\frac{\partial u}{\partial t}-\gamma \Delta u+a u+b|u| u+c|u|^{2} u+\nabla p=f_{0}(x, t).$

    Given a certain translational compactness assumption for the external forces, we obtain the uniform boundedness of the uniform attractor $\mathcal{A}^{\varepsilon}$ of the first system in $\left(H_{0}^{1}(\Omega)\right)^{3}$, and prove that when ε tends to 0, the uniform attractor of the first system $\mathcal{A}^{\varepsilon}$ converges to the attractor $\mathcal{A}^{0}$ of the second system.

  • research-article
    Biyun TANG , Yongyi LAN

    We investigate the Kirchhoff type elliptic problem

    $\left(a+b \int_{\mathbb{R}^{N}}\left[|\nabla u|^{2}+V(x) u^{2}\right] \mathrm{d} x\right)[-\Delta u+V(x) u]=f(x, u), \quad x \in \mathbb{R}^{N}$

    where both V and f are periodic in x, 0 belongs to a spectral gap of −Δ+V. Under suitable assumptions on V and f with more general conditions, we prove the existence of ground state solutions and infinitely many geometrically distinct solutions.

  • research-article
    Juan ZHAO , Pengxiu YU

    Let Ω be a smooth bounded domian in $\mathbb{R}^{2}$, $H_{0}^{1}(\Omega)$ be the standard Sobolev space, and $\lambda_{f}(\Omega)$ be the first weighted eigenvalue of the Laplacian, namely,

    $\lambda_{f}(\Omega)=\inf _{u \in H_{0}^{1}(\Omega), \int_{\Omega} u^{2} \mathrm{~d} x=1} \int_{\Omega}|\nabla u|^{2} f \mathrm{~d} x$

    where f is a smooth positive function on Ω. In this paper, using blow-up analysis, we prove

    $\sup _{u \in H_{0}^{1}(\Omega), \int_{\Omega}|\nabla u|^{2} f \mathrm{~d} x \leq 1} \int_{\Omega} e^{4 \pi f u^{2}\left(1+\alpha\|u\|_{2}^{2}\right)} \mathrm{d} x<+\infty$

    for any 0≤α<λf(Ω). Furthermore, extremal functions for the above inequality exist when α>0 is chosen sufficiently small.

  • research-article
    Pan MA , Maochun ZHU

    This paper is devoted to establishing the Adams-Onofri inequality with logarithmic weight for the second order radial Sobolev space defined on the unit ball in $\mathbb{R}^{4}$. By using this inequality we obtain the existence of solutions for mean field biharmonic equation with logarithmic weight.

  • research-article
    Chengwei YU

    This artical concerns the $C_{\mathrm{loc}}^{1, \alpha}$-regularity of weak solutions u to the degenerate subelliptic p-Laplacian equation

    $\Delta_{\mathcal{H}, p} u(x)=\sum_{i=1}^{6} X_{i}^{*}\left(\left|\nabla_{\mathcal{H}} u\right|^{p-2} X_{i} u\right)=0,$

    where $\mathcal{H}$ is the orthogonal complement of a Cartan subalgebra in SU(3) with the orthonormal basis composed of the vector fields X1,...,X6. When $1<p<2$, we prove that $\nabla_{\mathcal{H}} u \in C_{\mathrm{loc}}^{\alpha}$.

  • research-article
    Mohamed MELLAH , Ali HAKEM , Gongwei LIU

    This work considers the initial boundary value problem for a viscoelastic wave equation with a nonlinear boundary source term. Under suitable assumptions, we prove the existence of global weak solutions using the Galerkin approximation. Then, we give a decay rate estimate of the energy by making use of the perturbed energy method.

  • research-article
    Yanmin MU , Wenkang WANG , Jing ZHANG

    In this paper we firstly prove the global well-posedness for the compressible Hall-magnetohydrodynamic system in a bounded domain when the initial data is small. On this basis, we continue to study the convergence of the corresponding equations with the well-prepared initial data as the Mach number tends to zero.