【报告时间】2016年10月21日上午9:00
【报告地点】邵科馆报告厅 211
【邀请人】 韩高荣 教授、吴勇军 教授
【报告安排】 Time Title Speaker 9:00~9:20 Materials Science and Engineering at Penn State University Prof. Susan B. Sinnott (Department Head) 9:20~10:05 Materials Design and Discovery with Atomic Scale Modeling Prof. Susan B. Sinnott (Department Head) 10:05~10:50 Polymer Nanocomposites for Electrical Energy Storage and Conversion Prof. Qing Wang 10:50~11:35 Theory of Strain Phase Separation: Temperature-Strain-Domain Diagrams Prof. Long-Qing Chen
【报告人简介】 Susan B. Sinnott received her B.S. in chemistry from the University of Texas at Austin and her Ph.D. in physical chemistry from Iowa State University. She was a National Research Council Postdoctoral Associate at the Naval Research Laboratory and was on the faculty at the University of Kentucky prior to joining the University of Florida in 2000. In 2015 Susan joined the Pennsylvania State University as Professor and Department Head of Materials Science and Engineering. Research in the Sinnott Group is focused on the application of computational methods at the electronic-structure and atomic scales to examine a variety of materials and processes. These include the design of new materials and the investigation of the influence of grain boundaries, point defects, dopants, and heterogeneous interfaces on material properties. A major area of emphasis is the development of inventive methods to enable the modeling of new material systems at the atomic level. Susan is the author of over 220 technical publications, including over 200 refereed journal publications and 8 book chapters. She is a Fellow of the Materials Research Society, American Physical Society, American Ceramic Society, American Vacuum Society, and of the American Association for the Advancement of Science. Susan is a past President of the American Vacuum Society and is the Editor-in-Chief of Computational Materials Science. Qing Wang is a Professor of Materials Science and Engineering at the Pennsylvania State University, University Park, Pennsylvania, USA. He received his Ph.D. in 2000 at University of Chicago. Prior to joining the faculty at Penn State in 2002, he was a postdoctoral fellow at Cornell University. Among other awards, he has received the National Science Foundation CAREER Award, Rustum and Della Roy Innovation in Materials Research Award and Virginia S. and Philip L. Walker Faculty Fellow. His research programs are centered on using chemical and material engineering approaches towards the development of novel functional polymers and polymer nanocomposites with unique dielectric, electronic and transport properties for applications in energy harvesting and storage. Qing Wang is the author of about 120 articles in peer-review journals, including Nature, Science, PNAS, Nature Communications, Advanced Materials, Energy & Environmental Science, and Journal of American Chemical Society, etc. Long-Qing Chen is Donald W. Hamer Professor of Materials Science and Engineering, Professor of Engineering Science and Mechanics, and Professor of Mathematics at Penn State. He received his Ph.D. from MIT in Materials Science and Engineering in 1990 and joined the faculty at Penn State in 1992. He has published over 500 papers (with > 18,000 total citations and H-index of 67 according to the Web of Sciences and > 26,000 total citations and H-index of 76 according to the Google Scholar) in the area of computational microstructure evolution and multiscale modeling of structural metallic alloys, functional oxide thin films, and energy materials. He is a Fellow of the Materials Research Society (MRS), American Physical Society (APS), American Ceramic Society (ACerS), and American Society for Metals (ASM) and received the 2003 University Faculty Scholar Medal in Engineering and a Distinguished Professorship in 2012 at Penn State, a Guggenheim Fellowship in 2005, the 2011 TMS EMPMD Distinguished Scientist Award, the 2014 MRS Materials Theory Award, and 2015 Lee Hsun Lecture Award by the Shenyang Institute for Metals of the Chinese Academy of Sciences. He is the Editor-in-Chief for npj Computational Materials by the Nature Publishing Group.
【报告摘要】 Materials Science and Engineering at Penn State University（9:00-9:20） This presentation will discuss the research and educational activities taking place in the Department of Materials Science and Engineering at Penn State. With 30 full-time faculty based in the department, 30 affiliated faculty, 168 graduate students, and over 350 undergraduate students, this department is one of the largest in the United States. Members of the department have leadership roles in several Centers on campus, and the research taking place within the department is at the forefront of several sub-disciplines within the field, including the synthesis of transparent metals, novel two-dimensional materials, additive manufacturing, polymers and hydrogels, state-of-the-art characterization, and computational materials science across length scales. Examples of the research activities will be presented and discussed. Materials Design and Discovery with Atomic Scale Modeling（9:20-10:05） The discovery and design of new materials is the limiting factor to improve many existing technologies or to enable new applications. Material modeling methods across length scales are now widely applied and show promise for fulfilling the ultimate goal contained within the phrase “materials by design”. This presentation will review the evolution of some common material modeling methods and their integration with cutting-edge experimental methods as well as data informatics. Illustrative applications will be discussed within the context of novel two-dimensional and nanostructured systems, innovative porous materials for acid gas capture, and water interactions with metal and oxide surfaces. A future outlook of materials modeling within the context of material design and discovery will also be provided. Polymer Nanocomposites for Electrical Energy Storage and Conversion（10:05-10:50） This talk will describe our most recent efforts to develop ferroelectric polymer based multifunctional nanocomposites. As ferroelectric materials are capable of exhibiting many unique features including dielectric, piezoelectric, and pyroelectric properties due to its switchable spontaneous polarization under an electric field, the coupling across different fields (mechanical, thermal, and electromagnetic, etc) opens up a host of new collective properties and functionalities in the resulting composites. Specifically, the introduction of the inorganic nanostructures yields substantial enhancements in both electric displacement and breakdown strength, leading to the polymer nanocomposites with greatly improved energy densities for applications in advanced electrical energy storage devices. We have demonstrated a strong coupling of molecularly engineered ferroelectric polymers and ferromagnetic inorganics in the multiferroic polymer composites, thus opening an exciting research arena where various electro- and magneto-active nanostructures can be judiciously assembled to exhibit colossal collective properties. The structures and compositions of the ferroelectric polymer and ceramics have be designed and tuned to boost the electrocalric responses by optimizing the ferroelectric-paraelectric phase transition and the dielectric properties, which have profound implications for solid-state cooling devices that are energy efficient and environmental benign. Theory of Strain Phase Separation: Temperature-Strain-Domain Diagrams（10:50-11:35） Phase decomposition is a well-known process leading to the formation of two-phase mixtures with different compositions. Here we show that a strain imposed on a ferroelastic crystal promotes the formation of mixed phases and domains, i.e., leading to domain and phase de-strain process, with local strains determined by the uniform stress condition that can be graphically represented by a common tangent construction on the free energy versus strain curves. It is demonstrated that a domain structure can be understood using the concepts of domain/phase rule, lever rule, coherent and incoherent de-strain, and strain spinodal within the de-strain model description, in complete analogy to phase decomposition. The proposed de-strain model is tested and validated using phase-field simulations and experimental observations of PbTiO3 and BiFeO3 thin films as examples. The de-strain model provides a simple thermodynamic tool to guide and design domain structures of ferroelastic systems or the microstructures of a crystal separating to a mixture of two phases with different densities or molar volumes.
