arXiv subjects

Tetsuya Yamada

Publications and source records attributed to Tetsuya Yamada.

3 recordsLinked to original sources

arXiv2026

Stability of the critical constant steady state of a Keller--Segel model

In this paper, we prove the asymptotic stability of the critical constant steady state for a simplified parabolic--elliptic Keller--Segel system in $\mathbb{R}^N$ ($N \ge 3$), which admits a one-parameter family of constant steady states. Although the stability threshold for constant steady states is known, the critical case has remained open. We also show that the convergence rate in the critical case differs from the rates obtained for previously studied subcritical constant steady states.

math.AP↗

arXiv2025

Stability of constant steady states of an attraction-repulsion chemotaxis system

The Cauchy problem for the attraction-repulsion chemotaxis system in the whole $n$-dimensional space has uncountable constant steady states. In the attraction chemotaxis system, each positive constant steady state is stable if it is in a certain region. On the other hand, in the repulsion chemotaxis system, every positive constant steady state is stable. Our main purpose of this paper is to give a suitable condition under which the attraction-repulsion chemotaxis system has also stable constant steady states.

math.AP↗

arXiv2019

Molecular monolayer stabilizer for multilayer 2D materials

2D van der Waals materials have rich and unique functional properties, but many are susceptible to corrosion under ambient conditions. Here we show that linear alkylamines are highly effective in protecting the optoelectronic properties of these materials such as black phosphorous (BP) and transitional metal dichalcogenides. As a representative example, n-hexylamine can be applied in the form of thin molecular monolayers on BP flakes with less-than-2nm thickness and can prolong BP's lifetime from a few hours to several weeks and even months in ambient environments. Characterizations combined with our theoretical analysis show that the thin monolayers selectively sift out water molecules, forming a drying layer to achieve the passivation of the protected 2D materials. The monolayer coating is also stable in air, hydrogen annealing, and organic solvents, but can be removed by certain organic acids.

physics.app-ph↗