清华大学材料科学与工程研究院《材料科学论坛》

学术报告

报告题目：Size effects of Materials Confined to Nanometer Dimensions ?including 2D Membranes, Metal Clusters, and Vesicles: Nanocalorimetry ?and NMR Studies

报告人：Prof. Leslie Allen (University of Illinois，Material Science Dept.)

报告时间：2018年10月29日（星期一）下午3:30

报告地点：清华大学逸夫技术科学楼A512

联系人：宋成老师 62781275

欢迎广大师生踊跃参加！

报告摘要：
The nature of materials at nanometer size scales is ?fascinating and ubiquitous. In nanoscience, size-effects occur in ?2D-membranes (single/stacked), lipid-like vesicles (bioscience), magic ?number cluster formation, glass-transition of polymers, melting point ?depression (Gibbs-Thompson), odd/even chain length artifacts, ?nucleation controlled phase-transformations (nanoelectronics), etc.? ?This talk discuses experimental small-size material studies using ?Nanocalorimetry, AFM, XRD, TEM and more recently NMR. The studies ?follow the progressive and sometime abrupt changes in material ?properties during systematic incremental increase from 1-nm to bulk in ?several systems. Finally, I will discuss the future direction of our ?research, the development of a “Local Atomic-level Thermodynamic Probe ?for Nanoscience of 2D Membranes” that combining new synthesis, NMR, ?Nanocalorimetry, and computational DFT Methods. NMR adds new ?possibilities for research at a very small scale. While ?Nanocalorimetry yields average thermodynamic values at extremely small ?scales (one atomic layer of indium melting), it has no depth ?perception – it can’t reveal the underlying nature of the material at ?the atomic level. In contrast, the chemical shift from NMR has the ?ability to distinguish one atom-type from another.? However, it does ?not yield information of the local or composite thermal properties of ?the material.? Combining these two techniques with the modelling ?constructs made available with DFT computational machinery will ?potentially develop a new probe for material characterization at the ?nanometer size domain.

报告人简介：
Prof. Leslie Allen received his BS degree in mathematics ?(University of North Dakota, 1975), MS degree in physics (Clarkson ?University, New York, 1979), and PhD degree in materials science and ?engineering (Cornell University, 1990). He worked at University of ?Illinois. He has authored Over 100 journal papers and 4 patents. ?
SYNERGISTIC ACTIVITIES:
Innovations in Undergraduate and ?Teaching Teaching: Awarded/rated 10 years - Top 10% Teachersin ?Engineering (1993-96, 98, 2001, 2003, 2011-2013). Developed ?undergraduate senior Electronic Materials Laboratory that has been ?rated in the top 10% of all Engineering classes for 10 years. With ?over 15 contact-hours a week, the class attracts the best students in ?the department. Most of them later go to top graduate schools and ?obtain NSF/DOD scholarships. A new experiment is developed every ?2-year, typically coming from a problem in my research that is ?“simple” enough for them to solve in weeks, but deep enough as to ?stump us for months.
Development of Instrumentation ?Infrastructure Research Tools: Nanocalorimetry (NanoDSC) My group ?developed the most sensitive calorimeter device NanoDSC to date for ?material science research. In addition to serving on many NSF panel ?reviews, I have also served NIH review panel specifically to review ?MEMS based “bio-calorimetry” devices. I have given over 20 invited ?(National/International) talks on the device and research using ?NanoDSC for nanoscale materials. My group has been asked (and funded).