学科建设
杨纯教授报告通知

报告题目Microfluidic Manipulation of Flows/Particles and Ice Formation with Micro/Nanoscale Effects

中文标题: 微通道内部流场和颗粒行为调控 / 结冰过程中的微纳米尺度效应

邀请专家新加坡南洋理工大学 杨纯 教授

主持人:张华副校长

时间: 531号(星期五)1400   

地点:先进制造技术大楼附楼 124/126/127

报告内容:


Part I


Microfluidics not only holds the promise for the development of the next generation of instrumentation for chemical analyses and biomedical diagnoses, but also provides a well-controlled platform for performing basic physics, biology, chemistry, and engineering studies. These two important features make microfluidics research an academic frenzy in the past decade. A generic microfluidic platform should enable to perform multifunctions for manipulating sample solutes and particle/cells, such as sample preparation, pumping, mixing, reaction, concentration, separation, detection etc. However, due to size related constrains, it is quite challenging to achieve these functions by utilizing traditional techniques used in current laboratories. I will report our several years’ research activities on realization of the aforementioned microfluidic functions and fundamental understanding of relevant physical processes. The following topics will be included:


(1)     Enhancement of solute mixing via channel geometry with DC electroosmosis, AC electroosmosis with DC bias, and acoustically induced gas bubbles (for high viscous fluids with large throughput)


(2)     Microfluidic concentration of solutes through electrokinetically induced temperature gradient focusing


(3)     Separation and concentration of microparticles and cells by dielectrophoresis


(4)     On-demand sorting, trapping, merging and release of droplets in digital microfluidics


(5)     Use of microfluidics for studying particle thermophoresis with collective effects



Part II


Ice/snow accretions may cause severe consequences. Though various techniques of de-icing or anti-icing have been developed, more desirable approaches would be to hinder or prevent ice generation through changing surface structures or/and controlling icing processes. Here, I will report freezing of droplets from two different perspectives. First, we report retarded condensate freezing on micropillar patterned surfaces and examine the effects of pillar size and pitch as well as substrate wettability on freezing propagation velocity. Our experiments reveal three distinctive physical mechanisms/modes. An analytical model is proposed to describe the effects of wettability, morphology, and temperature on the frost spreading velocity. Second, we observed unique shape changes observed during the freezing process of nanofluid droplets. Instead of forming a pointy tip, the top of an ice droplet exhibits a flat plateau shape and such plateau is found to become larger with increasing particle concentration. We ascribe this characteristic shape change to an outward Marangoni flow which moves liquid from droplet interior to vertexes, thus engendering the volume redistribution and shape changes. We also found that the similar ring pattern occurs in freezing as in evaporation of nanofluid droplets.



报告人简历:


杨纯教授本科、硕士和博士分别毕业于清华大学、中国科学技术大学和加拿大Alberta大学。此期间,曾于1988-1994年在上海电力学院任讲师,1996-1999年,参与加拿大油砂工业主席项目在Syncrude 公司Edmonton 研究中心做研究工作。自199912月起,加入新加坡南洋理工大学机械与航天工程学院,历任助理教授,副教授,终身教授,现主持热流工程系工作。杨纯教授共发表SCI论文逾200篇,SCI核心引用量7000多次,H-index指数41Google引用量10000多次,H-index指数48。共拥有4项美国专利,出版了1本专著,同时参与撰写了23次著作章节。杨纯教授是美国机械工程学会会士ASME Fellow, 担任International Communications in Heat and Mass Transfer副主编,Journal of Modern Mechanical Engineering and Technology共同主编,另系列期刊编委(包括 Engineered Science - Energy & Environmental JournalMicrofluidics and Nanofluidics, International Journal of Emerging Multidisciplinary Fluid Sciences, EUREKA: Life Sciences, Journal of Fluids and Thermal Sciences, and Inventions and innovation in Energy and Thermal/Fluidic Science)和特邀编辑(包括Biomicrofluidics Journal, Microfluidics and Nanofluidics, and ASME Journal of Heat Transfer)。杨纯教授还担任过中国长江学者、中国国家自然科学奖、捷克国家自然科学基金、荷兰国家科技基金、荷兰科技研究委员会、以色列国家自然科学基金、加拿大国家科技委员会、香港科研基金委员会和澳大利亚科研基金委员会等国际评委。杨纯教授已受邀20多次参加ASME和其他国际学术会议,做大会(plenary、主题(keynotes)和特邀报告(invited talks)。此外,杨纯教授还组织和主持了多次重要的国际学术会议。目前为止,杨教授已经指导毕业了20位博士,其中2人获得了国家优秀海外留学生奖和国家青年千人人才计划