1. Department of Mechanical and Aerospace Engineering, University of Missouri, Columbia, MO 65211, USA.
2. School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China.
3. Piezoelectric Device Laboratory, School of Mechanical Engineering and Mechanics Ningbo University, Ningbo 315211, China.
4. Department of Physics, Yeshiva University, New York, NY 10016, USA.