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报告内容摘要：
Zhenhai Xia received his Ph.D. degrees from Northwestern Polytechnic University in 1990. He served on the faculty of Hebei University of Technology between 1990 and 1997 as professor and department chair between 1995 and 1997, Humboldt Research Fellow at German Aerospace Center (DLR) between 1997 and 1999, and Senior Research Associate in solid mechanics at Brown University, USA, between 1999 and 2006. He was a tenured Associate Professor of mechanical engineering of the University of Akron, and now an Associate Professor of materials science and engineering of the University of North Texas. Professor Xia has a background in Materials science and applied mechanics. His current research interests are focused on nanomechanics and nanomaterials, including polymer and ceramic composites, multifunctional materials (e.g. sensing damage and damage detection), biomimetic materials (e.g., gecko adhesion and self-cleaning, and biomimics), catalyst materials for clean energy (e.g., N-doped carbon nanotube and graphene for fuel cells and solar cells), and multiscale simulation. He has published near 100 publications, including two in Science. His research has been supported by NSF, NASA, U.S. Air Force, etc.

报告人简介：
Geckos can climb on almost any vertical surface, whether hydrophilic or hydrophobic, rough or smooth. The extraordinary ability of geckos is attributed to their fine hairy structure of their toes, which allow for intimate contacts between the nanohairs and almost any surface to secure high adhesion forces to defray gravity through van der Waals forces. Mimicking this biological system can lead to the development of a new class of advanced adhesives useful in various applications, including climbing robots, reusable tapes, super-grip tires, high efficiency breaks and rapid patch repairs on military vehicles. In this talk, I will present our recent efforts on the development of artificial dry adhesives. Using carbon nanotube arrays that are dominated by a straight body-segment but with curly entangled tip, we have created gecko-foot-mimetic dry adhesives that show macroscopic adhesive forces of ~100 N/cm2, almost ten times of that of a gecko foot. The mimics can be alternatively strong binding-on and easy lifting-off over various substrates for simulating the walking of a living gecko. To understand the underling mechanisms, a multiscale modeling approach was developed by combining large-scale finite element analysis, mesoscale coarse-grained modeling and fully atomic molecular dynamics simulation. Adhesion and friction behaviors of the nanotube arrays under various loading conditions are characterized and compared with experimental data. Good agreements are obtained, which give an insight into the anisotropic adhesive behaviors of carbon nanotubes on rough substrates.