学术报告：Hydrogen-bond memory and water-skin supersolidity resolving Mpemba Paradox----中国科学院兰州化学物理研究所

　　报告题目：Hydrogen-bond memory and water-skin supersolidity resolving Mpemba Paradox

　　报告人：孙长庆，南洋理工大学副教授

　　报告地点：理化楼一楼会议室

　　报告时间：5月23日（星期五）下午4：30

　　报告人简介：

　　孙长庆，辽宁建昌人。分别从武汉理工大学(1982)，天津大学(1987)，和澳大利亚默多克大学(1996) 获得物理学学士、硕士和表面物理专业博士学位。现为湖南省“芙蓉学者(湘潭大学)” 特聘教授，新加坡南洋理工大学副教授。英国物理学会和英国皇家化学学会高级会员。曾于2012年获夸瑞兹密国际科学一等奖。发表科技论文300余篇其中包括在《Chemical Society Reviews’14》、《Surface Science Reports’13》、《Chemical Reviews’12》、《Progress in Materials Science’09,03》、《Progress in Solid State Chemistry’07,06》、《Energy Environment Science’11》、《Nanoscale’10》等杂志发表的十余篇专题研究报告。

　　报告内容简介：

　　Hydrogen-bond memory and water-skin supersolidity resolving Mpemba Paradox

　　Chang Q Sun, NTU/Singapore, Ecqsun@ntu.edu.sg

　 We show that hydrogen bond (O:H-O) possesses memory (Panel a, H-bond linear velocity derived from measurements) to emit energy at a rate depending on its initial storage and that water skin exhibits supersolidity (b, Raman confirmation) to grade thermal conductivity with heat flowing outwardly. These identities resolve intrinsically the Mpemba paradox – (c) hotter water freezes faster than colder water does with (d) skin being warmer than the bulk. Heating stores energy into water by stretching the O:H nonbond and shortening the H-O bond via Coulomb coupling; cooling does oppositely, like releasing a highly deformed bungee, to emit heat at a rate of history dependence. Skin molecular undercoordination grades the local mass density, specific heat, and thermal conductivity, favoring heat outward flowing. Convection alone creates no Mpemba effect. Being sensitive to the source volume and the drain temperature, Mpemba effect proceeds only in the strictly non-adiabatic source-drain interface with a relaxation time that drops exponentially with the rise of the initial temperature of the source. Reproduction of the Mpemba effect (c, d) verified the validity and consistency of our recent findings on the structure order, O:H-O bond potentials, and physical anomalies of water ice [1-6]. 　　　

　　 1.Y. Huang, X. Zhang, Z. Ma, Y. Zhou, J. Zhou, W. Zheng, and C.Q. Sun, Size, separation, structure order, and mass density of molecules packing in water and ice. Scientific Reports, 2013. 3: 3005.

　　 2.Y. Huang, X. Zhang, Z. Ma, Y. Zhou, G. Zhou, and C.Q. Sun, Hydrogen-bond asymmetric local potentials in compressed ice. J. Phys. Chem. B, 2013. 117(43): 13639-13645.

　 3.C.Q. Sun, X. Zhang, J. Zhou, Y. Huang, Y. Zhou, and W. Zheng, Density, Elasticity, and Stability Anomalies of Water Molecules with Fewer than Four Neighbors. J Phys. Chem. Lett. 2013. 4: 2565-2570.

　　4.C.Q. Sun, X. Zhang, X. Fu, W. Zheng, J.-l. Kuo, Y. Zhou, Z. Shen, and J. Zhou, Density and phonon-stiffness anomalies of water and ice in the full temperature range. J. Phys. Chem. Lett. 2013. 4: 3238-3244.

　　5.C.Q. Sun, X. Zhang, and W.T. Zheng, Hidden force opposing ice compression. Chem Sci. 2012. 3: 1455-1460.

　　6.C.Q. Sun, Relaxation of the Chemical Bond. Springer Series in Chem Phys. Vol. 108. 807 pp., 2014 Heidelberg.