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报告内容摘要：
Lead zirconate titanate (e.g., PZT) is one of the most widely used ferroelectric materials, due to its excellent piezoelectric and ferroelectric properties. Many classes of sensors, actuators and memory elements, for use in diverse sectors of industry, ranging from aerospace, automotive, to medicine and microelectronics, rely on PZT. A key disadvantage of this material is that it, like most other ceramics, is brittle, and usually fractures at strains that are substantially less than 1%. As a result, devices built with PZT, in conventional layouts and processed using established, high temperature techniques, can only be subjected to small strain deformations, and can be integrated only with narrow classes of substrates. These limitations frustrate many potentially interesting applications, particularly those that require integration with the curvilinear, elastic surfaces of the human body for energy harvesting or health monitoring. We report a strategy for integrating nanoribbons of PZT, the ferroelectric ceramics, in ‘wavy’ geometries, on soft, elastomeric supports to achieve reversible, linear elastic responses to large strain deformations (i.e. stretchable properties), without any loss in ferroelectric or piezoelectric properties. Piezoresponse Force Microscope (PFM) is used to characterize the piezoelectricity and ferroelectricy of stretchable PZT ribbons. Theoretical and computational analysis of the mechanics accounts for these characteristics and also shows that the amplitudes of the waves can be continuously tuned with an applied electric field, to achieve a vertical (normal) displacement range that is near one thousand times larger than is possible in conventional planar layouts. The results suggest new design and application possibilities in piezo/ferroelectric devices.

报告人简介：
冯雪，男，1977年出生，清华大学副教授、博士生导师。2003年1月于清华大学获得博士学位，2004－2007年分别在伊利诺伊大学香槟城分校（UIUC）、加州理澳门太阳娱乐网站官网（Caltech，双聘）从事博士后研究。现任中国力学学会电子电磁器件工作委员会委员、微纳米力学工作组青年组委员、对外交流与合作委员会委员；国际期刊Journal of Mechanics and MEMS期刊编委。研究工作具有理论与实验相结合的特点，主要从事薄膜/界面力学、多物理场耦合行为与极端环境下实验力学的研究。至今已发表或接收SCI论文近50篇，其中包括（作为第一或通讯作者）发表在ACS Nano, Optics Express, Advanced Functional Materials，Langmuir，APL, AIAA Journal, IJSS和IJP等材料、物理、化学、航天航空、力学等领域的期刊。曾获2006年全国百篇优秀博士论文奖、2008年清华大学学术新人奖、2009年入选教育部“新世纪人才支持计划”。作为主要完成人之一获得2007年教育部自然科学奖一等奖、2008年教育部科技发明一等奖。目前已获得国家发明专利3项，自主软件著作权1项，申请国家发明专利10项（其中5项已公示）、国防专利2项。