气轨阻力与速度关系的研究

在气轨上测量了微小阻力和速度的关系.通过振动能准静态衰减的假设建模,并利用一种改进的线性拟合方法做数值微分,最终在3台气轨上得出了一致的经验规律:f(v)=αvγ,其中γ≈1.30.     

用力学方法测量一维有限狄拉克梳的电子态

通过对弦球链系统的力学性质测量,获得了一维有限狄拉克梳电子系统的电子态.实验结果表明:借助于对力学系统的测量获得的电子系统的能谱和波函数与理论计算符合得很好。     

A population-level model from the microscopic dynamics in Escherichia coli chemotaxis via Langevin approximation

Recent extensive studies of Escherichia coli (E. coli) chemotaxis have achieved a deep understanding of its mi- croscopic control dynamics. As a result, various quantitatively predictive models have been developed to describe the chemotactic behavior of E. coli motion. However, a population-level partial differential equation (PDE) that rationally incorporates such microscopic dynamics is still insufficient. Apart from the traditional Keller-Segel (K-S) equation, many existing population-level models developed from the microscopic dynamics are integro-PDEs. The difficulty comes mainly from cell tumbles which yield a velocity jumping process. Here, we propose a Langevin approximation method that avoids such a difficulty without appreciable loss of precision. The resulting model not only quantitatively repro- duces the results of pathway-based single-cell simulators, but also provides new inside information on the mechanism of E. coli chemotaxis. Our study demonstrates a possible alternative in establishing a simple population-level model that allows for the complex microscopic mechanisms in bacterial chemotaxis.