Global existence of solutions to the chemotaxis system with logistic source under nonlinear Neumann boundary condition

We consider classical solutions to the chemotaxis system with logistic source $f(u) := au-\mu u^2$ under nonlinear Neumann boundary condition $\frac{\partial u}{ \partial \nu } = |u|^{p}$ with $p>1$ in a smooth convex bounded domain $\Omega \subset \mathbb{R}^n$ where $n \geq 2$. This paper aims to show that if $p<\frac{3}{2}$, and $\mu >0$, $n=2$, or $\mu$ is sufficiently large when $n\geq 3$, then the parabolic-elliptic chemotaxis system admits a unique positive global-in-time classical solution that is bounded in $\Omega \times (0, \infty)$. The similar result is also true if $p<\frac{3}{2}$, $n=2$, and $\mu>0$ or $p<\frac{7}{5}$, $n=3$, and $\mu$ is sufficiently large for the parabolic-parabolic chemotaxis system.