Acoustic focusing through two layer annuluses in air
Yi-Jun Guan(管义钧), Hong-Xiang Sun(孙宏祥), Shu-Sen Liu(刘树森), Shou-Qi Yuan(袁寿其), Jian-Ping Xia(夏建平), Yong Ge(葛勇)
Chin. Phys. B . 2016, (10): 104302 -104302 .  DOI: 10.1088/1674-1056/25/10/104302