关于台湾大学张建成教授学术报告的通知

报告题目：A Periodic Array of Nano-scale Parallel Slats for High-Efficiency Electroosmotic Pumping

报 告 人：张建成  教授

时        间：9月17日 上午 8:15-9:15

地点：浙江大学玉泉校区教四311教室

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报告简介：

 It is known that the eletroosmotic (EO) flow rate through a nano-scale channel is extremely small. A channel made of a periodic array of slats is proposed for high EO flow rates. The simple array is complicated enough that four length scales are involved: the vertical period 2L, lateral period 2aL, width of the slat 2cL as well as the Debye length . The EO pumping rate is determined by the normalized lengths: a, c or the porosity of slats  and the dimensionless electrokineticwidth . In a nano-scale channel, K is of order unity or less. EO pumping in both longitudinal and transverse directions (denoted as LEOP and TEOP, respectively) is investigated by solving the Debye-Hückel approximation and viscous electro-kinetic equation. The main findings include that (i) the EO pumping rates of LEOP for small K are remarkably improved (by one order of magnitude) when we have longer slats ( ) and a large porosity of slats ( > 0.7); (ii) the EO pumping rates of TEOP for small K can also be much improved but less significantly with longer slats and a large porosity of slats. Nevertheless, it must be noted that in practice K cannot be made arbitrarily small as the criterion of for the reference potential at the channel center put lower bounds on K; in other words, there are geometrical limits for the use of the Poisson-Boltzmann equation.

Bio:

Dr. Jiancheng Chang attended National Taiwan University (NTU, 1976-1980) and National Tsing-Hua University (1980-1982), receiving BE degree in Chemical Engineering and MS degree in Applied Mechanics, respectively. In 1982, he was awarded a University Fellowship to do an advanced graduate study at University of California, Berkeley and received PhD degree (Applied Mathematics) in 1985.

After obtaining his PhD degree, Dr. Chang worked at Lawrence Berkeley National Laboratory as a Research Associate. Since 1987, he has been a faculty member at the NTU Institute of Applied Mechanics, where he is currently a distinguished professor. From July 2005 to June 2009, Dr. Chang had held a joint appointment in Academia Sinica where he established Division of Mechanics and served as its first director for 4 years. From August 2009, Prof. Chang had served a 3-year term as the Director of the NTU Institute of Applied Mechanics.

Prof. Chang has done research works in the fields of fluid mechanics, in particular, aerodynamics. Recently, he has also been engaged research in microfluidics, biological modeling and imaging as well as in mechanics of nano-materials. He has published more than 110 papers in internationally renowned journals such as Journal of Fluid Mechanics, Physics of Fluids, Physical Review A,B,E., Lab on a Chip, Ultrasound in Medicine and Biology. Over the past 26 years, Prof. Chang has supervised 20 doctoral theses and more than 80 MS theses.