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美国爱荷华州立大学(Iowa State University)王信伟教授讲座通知
发布时间:2017-04-17 15:41:25 点击量:601

       受能动学院王秋旺教授邀请,美国爱荷华州立大学机械工程系王信伟将教授于2017425日到427日访问我校,并为全校师生做一场学术报告,欢迎大家积极参加。

 

讲座人简介:王信伟,普渡大学博士,美国爱荷华州立大学机械工程系终身教授。1989年至1996就读于中国科技大学热科学与能源工程系,分别获学士、硕士学位,1997至年2001年在美国普渡大学机械工程系攻读博士学位,2001年至2007年在美国内布拉斯加大学林肯分校工作任助理教授,副教授,2008年起在爱荷华州立大学机械工程系任副教授、教授。王信伟教授于2011年和2014年被选为美国航空航天学会Associate Fellow 和美国机械工程师学会Fellow 目前担任International Journal of Thermophysics副主编,同时是Scientific Reports, Journal of Nanoscience and Nanotechnology, Journal of Thermal Stresses, Journal of Visual Engineering等国际期刊的编委。

       多年来,王信伟教授主要从事微尺度材料领域前沿课题的研究,包括纳米结构对声子散射的分子动力学研究以及微米/纳米低维材料热物性的非接触非破坏性测量、基于拉曼散射的原子量级分辨率的温度测定和物体界面的能量耦合的测量等,开展了碳纳米管,纳米薄膜,微米材料和生物材料的传热特性及结构的研究。

       王教授发展了8种全新的瞬态微/纳米测量技术,首次测量了小于10纳米材料的温度和近场光学下的热响应。他领导实验室利用拉曼散射技术首次获得了纳米尺度的空间温差的测量,并以此测定了石墨烯-基底之间的能量耦合。利用物理差分的测量方法,他领导实验室首次实现了小于纳米厚度材料的热导系数在毫米长度的测量。他提出和发展的热扩散阻力系数(Thermal Reffusivity)深刻揭示了材料内部结构缺陷对电子和声子的能量传递的影响。 材料的德拜温度可以直接从其对温度的变化曲线获得。 同时材料的结构特征尺寸可以从其绝对零度极限的残余值获得。其研究工作获得美国自然科学基金、美国能源部、陆军、海军和空军等30余个项目的资助和支持,担任9个国际期刊的编委。于2013年获得了普渡大学的首届Viskanta Fellow,以表彰他在热学领域的独立和前沿贡献。

 

时间:2017426日下午3:00-5:00

 

地点:东三楼东汽报告厅

 

题目:Down to Atomic-level Direct Thermal Probing and Energy Transport Characterization

 

报告摘要:Temperature is one of the most important physical parameters for characterizing and understanding thermal transport capacity of materials, looking into the physics behind photon-induced material processing, and unrevealing interface energy exchange/coupling. This talk will cover our new technology development and frontier research on thermal probing based on Raman scattering, a technology traditionally widely used for structure analysis. The Raman-based thermal probing in three areas will be covered. The first one is micro/submicron particle induced near-field effect. This phenomenon has been widely used in surface nanoscale structuring and imaging. For the first time, we have accomplished experimental study on nanoscale mapping of particle-induced thermal, stress, and optical fields under near-field excitation. The mapping provides consistent knowledge of conjugated thermal, stress, and near-field focusing at a 20 nm resolution. This represents a very exciting advance for far-field thermal probing of near-field thermal phenomenon with an ultra-high resolution. Particles as small as 160 nm can be clearly mapped employing this technique. The second area is near-field optical focusing by an atomic force microscope. A thermal probing resolution as small as 5 nm has been achieved. We have undertaken pioneering work on the near-filed thermal response, nonlinear optical absorption, and ballistic heat conduction around a region of a few nm. The third area is interface energy coupling between graphene and a substrate. A spatial resolution as good as 1~2 nm has been achieved. For the first time, we are able to distinguish the temperature difference between two materials a few nm apart. Interface energy, optical, and mechanical couplings will be reported. This provides one of the most advanced knowledge base about the physical behavior of graphene on a substrate. Our most recent advance has achieved energy state-resolved Raman to characterize electron diffusion and interface energy coupling of 2D atomic layer materials. This represents accurate characterization by eliminating the errors of laser absorption calculation and Raman properties temperature coefficient calibration.

 

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