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Synthesis of Transparent Oxide Films with Enhanced Near Infra-red Reflecting Properties

Speaker:Prof. Yip-Wah Chung
Affiliation:Department of Materials Science and Engineering, and Department of Mechanical Engineering Northwestern University, Evanston, Illinois, USA
Date:June 12, 2009 (Fri)
Time:5:00-6:30 p.m.
Venue:Lecture Theatre P2, LG1/F, Chong Yuet Ming Physics Building, HKU


Sunlight incident on vehicles such as cars and planes gives rise to two problems. First, absorption of ultraviolet radiation contributes to degradation of fabrics and polymers in vehicles. Second, absorption of visible and infra-red radiation results in vehicle heating that requires the typical use of an oversized air conditioning unit for passenger comfort. This in turn reduces the fuel economy. Therefore, it is desirable to develop materials for these vehicles that are transparent to the visible, absorbing to ultraviolet and reflecting to infra-red. Two general approaches are available: optical interference and plasma resonance. This talk describes research studies based on the second approach. In this work, we start with a titanium dioxide matrix, which is transparent to visible light and absorbs ultraviolet at wavelengths < 400 nm. Appropriate metal atoms are then incorporated into this matrix, resulting in a film that acts as a plasma with specific electromagnetic properties. Successful development of these thin films with the above desirable attributes will be presented.


About the Speaker:

Yip-Wah Chung is Professor of Materials Science and Engineering and Mechanical Engineering at Northwestern University. He obtained his BS and MPhil from the University of Hong Kong and PhD in Physics from the University of California at Berkeley. He has published over 180 papers in surface science, thin films, and tribology, and two textbooks – one on surface science and spectroscopy, and one on introduction to materials science and engineering. He was named Fellow, ASM International; Fellow, AVS; and Fellow, Society of Tribologists and Lubrication Engineers. His other awards include the Innovative Research Award and Best Paper Awards from the ASME Tribology Division, Technical Achievement Award from the National Storage Industry Consortium (now Information Storage Industry Consortium), Bronze Bauhinia Star Medal from the Hong Kong SAR Government, and Advisory Professor from Fudan University. Dr. Chung served two years as program officer in surface engineering and materials design in the Civil and Mechanical Systems Division at the National Science Foundation, acting as the Division representative for the nanoscale science and engineering initiative. He has served many years on the Hong Kong Research Grants Council and is currently a member of the University Grants Committee. He is Director of the NSF Summer Institute on Nanomechanics, Nanomaterials and Micro/Nanomanufacturing. In his spare time, he is often seen doing recreational flying all over the US. In 2003, he earned his commercial multi-engine instrument and advanced ground instructor certificates.



Physics colloquium series is organized to introduce cutting edge researches and new development in physics, designed to be suitable to graduate and undergraduate students, and also to scientists working on different fields. Each colloquium will generally start with an extensive introduction of the background of the field, followed by forefront research topics and results. The colloquium will serve as an education forum for students and laymen alike, and also serve as a platform for exchange and update their knowledge of various branches of physics among academic staff members.