报告题目：Size-dependent Phase Behaviors of Nanomaterials
报告人：Prof. Hengzhong Zhang（张衡中 研究员）
Nanomaterials may exhibit size-dependent phase behaviors not seen in their bulk counterparts. Examples include that bulk structures that are stable only at high temperatures and/or high pressures can be stabilized at ambient conditions, and the transition pressure depends on the particle size in pressure-induced phase transformations. Our extensive research revealed that the phase stability reversal in nanocrystalline materials stem from the modified energetics due to the surface energies of nanoparticles; the size-dependent phase transformation kinetics relies on the contact probability of nanoparticles for interface nucleation, and nanoparticles can grow via the orientated attachment pathway rather than the classical Ostwald ripening. These size-dependent material behaviors can be utilized for achieving novel material functions and properties。
Pro. Hengzhong Zhang is a Staff Scientist at the Center for High Pressure Science & Technology Advanced Research (HPSTAR). He received his Ph.D. in Metallurgical Physical Chemistry from Central South University (CSU) in 1991. Then, he worked as a faculty member at CUS till 1995 and visited the Energy Research Centre of the Netherlands in 1996. Following post-doctoral work at the University of WisconsinMadison, he became a Staff Researcher there till 2002. Since then, he worked as a Staff Scientist at the University of California Berkeley till 2015. Zhang was a guest editor for a themed issue of CrystEngComm in 2014 and a leading organizer of a Symposium of the 2014 MRS Spring Meeting. He had undertaken many US NSF and US DOE projects either as a PI/co-PI or a leading investigator. Zhang’s research spans several fields, including Nanoscience, Physical Chemistry, Materials Chemistry, Geochemistry and Mineralogy. He has authored or co-authored ~ 80 peer-reviewed scientific publications, which have been cited more than 10,000 times so far.