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Xiaoqian Xu

Assistant Professor of Mathematics at Duke Kunshan University
DKU Faculty

Selected Publications


EXISTENCE OF WEAK SOLUTIONS TO p-NAVIER-STOKES EQUATIONS

Journal Article Discrete and Continuous Dynamical Systems - Series B · April 1, 2024 We study the existence of weak solutions to the p-Navier-Stokes equations with a symmetric p-Laplacian on bounded domains. We construct a particular Schauder basis in W01, p(Ω) with divergence free constraint and prove existence of weak solutions using the ... Full text Cite

Tumor boundary instability induced by nutrient consumption and supply

Journal Article Zeitschrift fur Angewandte Mathematik und Physik · June 1, 2023 We investigate the tumor boundary instability induced by nutrient consumption and supply based on a Hele-Shaw model. The model describes the geometric evolution of the tumor region and is derived from taking the incompressible limit of a cell density model ... Full text Cite

DISSIPATION ENHANCEMENT FOR A DEGENERATED PARABOLIC EQUATION

Journal Article Communications in Mathematical Sciences · January 1, 2023 In this paper, we quantitatively consider the enhanced-dissipation effect of the advection term to the parabolic p-Laplacian equations. More precisely, we show the mixing property of flow for the passive scalar enhances the dissipation process of the p-Lap ... Full text Cite

Suppression of epitaxial thin film growth by mixing

Journal Article Journal of Differential Equations · April 25, 2022 We consider following fourth-order parabolic equation with gradient nonlinearity on the two-dimensional torus with and without advection of an incompressible vector field in the case 2 Full text Cite

Convection-induced singularity suppression in the keller-segel and other non-linear PDEs

Journal Article Transactions of the American Mathematical Society · January 1, 2021 In this paper we study the effect of the addition of a convective term, and of the resulting increased dissipation rate, on the growth of solutions to a general class of non-linear parabolic PDEs. In particular, we show that blow-up in these models can alw ... Full text Cite

Stability of Blowup for a 1D Model of Axisymmetric 3D Euler Equation

Journal Article Journal of Nonlinear Science · December 1, 2018 The question of the global regularity versus finite- time blowup in solutions of the 3D incompressible Euler equation is a major open problem of modern applied analysis. In this paper, we study a class of one-dimensional models of the axisymmetric hyperbol ... Full text Cite

Continuous and discrete one dimensional autonomous fractional odes

Journal Article Discrete and Continuous Dynamical Systems - Series B · October 1, 2018 In this paper, we study 1D autonomous fractional ODEs D c γu = f(u); 0 < γ < 1, where u : [0;∞) → R is the unknown function and D c is the generalized Caputo derivative introduced by Li and Liu ( arXiv:1612.05103). Based on the existence and uniqueness the ... Full text Cite

A note on one-dimensional time fractional ODEs

Journal Article Applied Mathematics Letters · September 1, 2018 In this note, we prove or re-prove several important results regarding one dimensional time fractional ODEs following our previous work Feng et al. [15]. Here we use the definition of Caputo derivative proposed in Li and Liu (2017) [5,7] based on a convolu ... Full text Cite

A Locally Gradient-Preserving Reinitialization for Level Set Functions

Journal Article Journal of Scientific Computing · April 1, 2017 The level set method commonly requires a reinitialization of the level set function due to interface motion and deformation. We extend the traditional technique for reinitializing the level set function to a method that preserves the interface gradient. Th ... Full text Cite

Suppression of Chemotactic Explosion by Mixing

Journal Article Archive for Rational Mechanics and Analysis · November 1, 2016 Chemotaxis plays a crucial role in a variety of processes in biology and ecology. In many instances, processes involving chemical attraction take place in fluids. One of the most studied PDE models of chemotaxis is given by the Keller–Segel equation, which ... Full text Cite

EXISTENCE OF WEAK SOLUTIONS TO p-NAVIER-STOKES EQUATIONS

Journal Article Discrete and Continuous Dynamical Systems - Series B · April 1, 2024 We study the existence of weak solutions to the p-Navier-Stokes equations with a symmetric p-Laplacian on bounded domains. We construct a particular Schauder basis in W01, p(Ω) with divergence free constraint and prove existence of weak solutions using the ... Full text Cite

Tumor boundary instability induced by nutrient consumption and supply

Journal Article Zeitschrift fur Angewandte Mathematik und Physik · June 1, 2023 We investigate the tumor boundary instability induced by nutrient consumption and supply based on a Hele-Shaw model. The model describes the geometric evolution of the tumor region and is derived from taking the incompressible limit of a cell density model ... Full text Cite

DISSIPATION ENHANCEMENT FOR A DEGENERATED PARABOLIC EQUATION

Journal Article Communications in Mathematical Sciences · January 1, 2023 In this paper, we quantitatively consider the enhanced-dissipation effect of the advection term to the parabolic p-Laplacian equations. More precisely, we show the mixing property of flow for the passive scalar enhances the dissipation process of the p-Lap ... Full text Cite

Suppression of epitaxial thin film growth by mixing

Journal Article Journal of Differential Equations · April 25, 2022 We consider following fourth-order parabolic equation with gradient nonlinearity on the two-dimensional torus with and without advection of an incompressible vector field in the case 2 Full text Cite

Convection-induced singularity suppression in the keller-segel and other non-linear PDEs

Journal Article Transactions of the American Mathematical Society · January 1, 2021 In this paper we study the effect of the addition of a convective term, and of the resulting increased dissipation rate, on the growth of solutions to a general class of non-linear parabolic PDEs. In particular, we show that blow-up in these models can alw ... Full text Cite

Stability of Blowup for a 1D Model of Axisymmetric 3D Euler Equation

Journal Article Journal of Nonlinear Science · December 1, 2018 The question of the global regularity versus finite- time blowup in solutions of the 3D incompressible Euler equation is a major open problem of modern applied analysis. In this paper, we study a class of one-dimensional models of the axisymmetric hyperbol ... Full text Cite

Continuous and discrete one dimensional autonomous fractional odes

Journal Article Discrete and Continuous Dynamical Systems - Series B · October 1, 2018 In this paper, we study 1D autonomous fractional ODEs D c γu = f(u); 0 < γ < 1, where u : [0;∞) → R is the unknown function and D c is the generalized Caputo derivative introduced by Li and Liu ( arXiv:1612.05103). Based on the existence and uniqueness the ... Full text Cite

A note on one-dimensional time fractional ODEs

Journal Article Applied Mathematics Letters · September 1, 2018 In this note, we prove or re-prove several important results regarding one dimensional time fractional ODEs following our previous work Feng et al. [15]. Here we use the definition of Caputo derivative proposed in Li and Liu (2017) [5,7] based on a convolu ... Full text Cite

A Locally Gradient-Preserving Reinitialization for Level Set Functions

Journal Article Journal of Scientific Computing · April 1, 2017 The level set method commonly requires a reinitialization of the level set function due to interface motion and deformation. We extend the traditional technique for reinitializing the level set function to a method that preserves the interface gradient. Th ... Full text Cite

Suppression of Chemotactic Explosion by Mixing

Journal Article Archive for Rational Mechanics and Analysis · November 1, 2016 Chemotaxis plays a crucial role in a variety of processes in biology and ecology. In many instances, processes involving chemical attraction take place in fluids. One of the most studied PDE models of chemotaxis is given by the Keller–Segel equation, which ... Full text Cite

Fast growth of the vorticity gradient in symmetric smooth domains for 2D incompressible ideal flow

Journal Article Journal of Mathematical Analysis and Applications · July 15, 2016 We construct initial data for the two-dimensional Euler equation in a bounded smooth symmetric domain such that the gradient of vorticity in L∞ grows as a double exponential in time, for all time. Our construction is based on the recent result by Kiselev a ... Full text Cite

One-dimensional model equations for hyperbolic fluid flow

Journal Article Nonlinear Analysis, Theory, Methods and Applications · July 1, 2016 In this paper we study the singularity formation for two nonlocal 1D active scalar equations, focusing on the hyperbolic flow scenario. Those 1D equations can be regarded as simplified models of some 2D fluid equations. ... Full text Cite

Lower bounds on the mix norm of passive scalars advected by incompressible enstrophy-constrained flows

Journal Article Nonlinearity · January 1, 2014 Consider a diffusion-free passive scalar θ being mixed by an incompressible flow u on the torus d. Our aim is to study how well this scalar can be mixed under an enstrophy constraint on the advecting velocity field. Our main result shows that the mix-norm ... Full text Cite