香港工程科学院院士香港大学Alfonso H.W. Ngan (颜庆云) 教授讲学通知

2018-06-15 12:43

应我校材料科学与工程学院黄永江副教授邀请,香港工程科学院Fellow,香港大学工程学院副院长颜庆云教授近日将来我校访问,并进行学术讲座,欢迎感兴趣的老师同学参加。

报告人简介:

颜庆云教授现为香港大学教授,香港工程科学院Fellow,香港大学工程学院副院长,力学领域顶级期刊International Journal of Plasticity副主编,在金属材料的力学性能-结构相关性、薄膜材料的力学性能、力学性能表征、位错理论、原子尺度金属材料的结构特征、金属材料的缺陷理论及仿真等方面在国际上享有盛誉。在国际高水平期刊发表学术论文210余篇,被引用4300余次,H因子达32

报告一

题目:Introduction to PhD Studies at the University of Hong Kong

时间:201861913:30

地点:材料学院322

摘要:Mechanics and materials teaching and research at HKU dates back to 1912 when the university opened its door to students. In modern times, the Department of Mechanical Engineering at HKU is engaged in an exciting spectrum of research areas in materials engineering. In this short talk, a brief introduction of PhD studies at HKU will be given by Prof. Ngan.  

报告二

题目:Novel nickel-hydroxide/oxyhydroxide actuating material that can be triggered by both light and electricity

时间2018619日上午14:00

地点:材料学院322

摘要:Here we report a novel actuating material–nickel hydroxide-oxyhydroxide–that exhibits enormous actuation due to a volume change stimulated either electrochemically, or by illumination of visible light of low intensities. For electrochemical actuation, Ni(OH)2/NiOOH is capable of undergoing fast, reversible, and large actuation in alkaline electrolytes under potentials of less than 1 V, due to a redox reaction involving volume changes. On the other hand, the light actuation of Ni(OH)2/NiOOH is due to its  turbostratic crystal structure which is capable of intercalating water molecules. It is shown that the intercalated water can be rapidly and reversibly desorbed into the environment under visible light of low intensities, resulting in fast actuation driven wirelessly by light.

By electroplating the actuating material on passive substrates, we have fabricated film-actuators capable of undergoing reversible bending and curling with an intrinsic actuating stress of tens of megapascals at response rates in the order of tens to hundreds of degrees per second, which are comparable to mammalian skeletal muscles. Also, by intentionally electroplating the nickel hydroxide-oxyhydroxide on selected areas of the substrate, we have also fabricated actuation devices of varies shapes and functions, e.g. a hinged actuator that can lift objects ~100 times of the weight of the actuating material is achieved, and other examples showing the potential use in robotic devices. The light-induced actuation mechanism reported here has the potential for realizing wirelessly powered micro-robotic devices.

报告三

题目:Stochastic and Jerky Nature of Plasticity in Small Material Volumes

时间2018619日上午15:00

地点:材料学院322

摘要:In the field of continuum mechanics, material plasticity is described by constitutive laws in which the deformation process is assumed to be smooth. The established experimental observations, however, indicate that material deformation is often a jerky process with discrete events occurring in a stochastic manner. For bulk materials, such discrete events may not be important as they are simply small fluctuations superimposed on a smooth, mean-field behaviour well describable by continuous laws. In micron-sized material volumes, however, such discrete events may correspond to very large strain changes so that the overall behaviour is no longer describable by smooth laws. Furthermore, in micron-sized materials, the interaction of defects, such as dislocations, may be fundamentally different from bulk situations. In this talk, the corresponding experimental observations in a wide range of materials, including crystalline metals and alloys, bulk metallic glasses, polymers and anodized aluminium oxide, will be reviewed. These experiments comprise sharp-tip nanoindentation on flat surfaces, as well as compression of micro-pillars, under both ramping-load and steady-load (i.e. creep) situations. The stochastic and jerky nature of the plastic events in these cases calls for a new approach to model plasticity in small volumes, and attempts based on statistical ensembles will be discussed.

颜庆云教授拟在我校招收2019年级博士生(20199月入学),研究方向为:

(1)     Novel actuating materials for robotic applications

(2)     Direct printing of ceramic materials by microfluidic electrodeposition

(3)     Computational dislocation-based plasticity

欢迎感兴趣的材料、物理、化学、机械等背景的2019年毕业的本科生或者研究生申请。感兴趣的同学可直接联系 Prof. Ngan,联系方式:hwngan@hku.hk,或者可以于2018619日下午1600-1730在材料学院427面谈。

个人主页:  http://hub.hku.hk/cris/rp/rp00225 ,个人英文简介请见附件!

材料科学与工程学院

2018615

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