学术报告（2019年3月18日 周一 16:00-17:00）

主持人：董建文教授

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【报告摘要】

   Bacteria with helically shaped flagella are known to experience rheotaxis when subject to shear flows. Interaction between drift induced by the helical shape of the flagella and viscous drag on the body of the bacteria leads to a preferred bacteria orientation and bacteria are observed to drift perpendicular to the shear plan. The statistics of the rheotaxis including velocity distribution and the orientation distribution was determined in Poiseuille flow by experiments. To understand the hydrodynamics of swimming bacteria in the shear flow, the model combining the classical Jeffery orbit and rheotatic force was developed to predict the orientation of the bacteria in the flow. The numerical solutions based on the Brownian motion dynamics showed the nice agreement between the theory and the experiments.

While in the crowded state, bacteria collective motion occurs. Two control parameters, concentration and external driving flow, are examined to stimulate the collective motion (active flow). It turns out that the high concertation and weak external flow push the bacteria in the collective motion state. In addition, we found the surface effect on the collective motion, which suppress the correlation length.

【报告人简介】

经光银 男, 教授,  2002年本科毕业于中山大学物理系，2007年于北京大学物理学院获凝聚态物理学博士学位；2007-2008年在巴黎物理化学学校（ESPCI）开展高分子物理和界面效应博士后研究，2008-2009年在巴黎十一大流体力学力学实验室（FAST）从事复杂流体和胶体动力学博士后研究。2009年9月到西北大学物理系工作至今，主要研究方向为软物质与生物物理，主要包括软凝聚态物理中的界面浸润，远离平衡态主动物理系统的实验与理论研究。主持国家自然基金青年、面上项目，陕西省自然科学基金重点项目、面上项目，教育部留学回国启动等项目。在领域内权威杂志Phys. Rev. E; Phys. Rev. B; New J. Phys.; Adv. Materials; ACS Nano; Soft Matter等发表学术论文50余篇。