报告内容摘要：
A general picture of the interactions between gas and water molecules will be drawn as it emerges from the established crystal structures. Notably, the cubic structure sI is the best polyhedral solution to the so-called Kelvin problem which tries to divide space with minimal partitional area. Thus, this structure can be considered as the arrangement with a maximal contact of gas molecules to the water polygons with a minimum amount of water molecules. In other words, gas hydrates structures can be considered as the result of a systematic hydrophobic hydration in which the water molecules arrange around gas molecules without sacrificing H-bonds. Attractive van der Waals interactions as well as excluded-volume effects strongly influence the physical properties of gas hydrates. Thermal conductivity, thermal expansion and compressibility show that guest-specific signatures exist. Understanding these interactions will lead to better predictions of the thermodynamic properties ofgas hydrates. Bridging the gap between the entropically driven low solubility of most gases in liquid water and the systematic hydrophobic hydration in crystalline gas hydrates is a crucial point for nucleation and growth of gas hydrates from liquid water and of considerable importance for questions related to flow assurance. Finally, the role of defects in the water framework for gas diffusion and gas exchange processes in gas hydrates will be elucidated.  

 
报告人简历：
Prof. Werner F. Kuhs received his diploma on Mineralogy in University of Freiburg in 1975 and got his PhD on Crystal Growth in University of Freiburg in 1978. He acquired the habilitation faculty of Crystallography/Physics in University (TH) Karlsruhe and is a full professor (Crystallography) at the University of G?ttingen/ Germany with numerous BSc, MSc and PhD students. Prof. Werner F. Kuhs is currently leading activities in the field of gas hydrates and ice research with a focus on materials properties and the kinetics of formation and decomposition. Energy related projects; linkage of materials properties to geophysical signatures; involvement in ice core research for climate reconstruction. He has published more than 130 papers in peer-reviewed journals, mainly in the fields of ice and gas hydrate research as well as crystallography and materials science, and has been honored with the Victor -MoritzGoldschmidt-Prize of the German Mineralogical Society (DMG). Prof. Werner F. Kuhs is an elected member of the German Academy of Science (Leopoldina), chairman of the International Committee of Physics and Chemistry of Ice, council member of the International Glaciological Society, coeditor of Acta Crystallographica A.