振动马达的反常输运行为

Directed transport in a periodic system has potential applications in many processes of physics, chemistry, and biology. Recently, an interesting phenomenon termed absolute negative mobility stimulated extensive attention. This phenomenon describes an anomalous transport behavior in which particles always move in a direction opposite to the net acting force. The model of vibrational motor is obtained when the role of noise in a Brownian motor is played by a time-periodic force. This item investigate anomalous transport behaviors in the vibrational motor when it subject to coexisting attractors, time delay or noise. The numerical simulation method is employed to reveal these abnormal transport behaviors and the nonlinear dynamic theory is used to analysis the underlying mechanism. These researches can provide theoretical principle for understanding the nonequilibrium transport processes, and could be used for the separation and fractionation of colloids, biology molecules and cells.

周期系统中的定向输运问题在物理、化学与生物的很多过程中都有潜在应用。最近，一种叫做绝对负迁移率的有趣现象引起了广泛的关注。该现象描述了粒子的运动方向始终与净作用力方向相反的反常输运行为。用一个时间周期信号扮演布朗马达中噪声的角色，就得到振动马达的模型。本项目研究共存吸引子、时间延迟或者噪声影响下振动马达的反常输运行为。利用数值模拟方法揭示这些反常输运行为并利用非线性动力学理论分析相应的的机制。这些研究可以为理解非平衡输运过程提供理论基础，并对胶体和生物分子与细胞的分离提纯具有应用前景。

周期系统中的定向输运问题在物理、化学与生物的很多过程中都有潜在应用。周期系统的反常输运行为是近年来统计物理领域的研究热点。本项目深入地研究了共存吸引子、时间延迟、噪声、势垒高度影响下振动马达的反常输运和扩散行为。利用数值模拟方法揭示这些行为的规律并利用非线性动力学理论分析相应的机制。核心研究结果如下：(1) 共存吸引子可以诱导绝对负迁移率现象、非线性负迁移率现象、微分负迁移率现象以及巨扩散现象；(2) 存在一个临界的偏置外力，时间延迟在这个临界值附近可以增强或削弱扩散过程；(3) 振动马达中可以在温度较高的情况下出现反常输运行为。(4) 周期信号可以诱导振动马达的棘齿效应。这些研究可以为理解非平衡输运过程提供理论基础，并对胶体和生物分子与细胞的分离提纯具有应用前景。