論文(共著)が Japanese Journal of Applied Physics に掲載されました。

論文(共著)が Japanese Journal of Applied Physics に掲載されました。

H. Tanaka, Y. Wada, Y. Mizuno, and K. Nakamura, “Effect of holed reflector on acoustic radiation force in noncontact ultrasonic dispensing of small droplet,” Jpn. J. Appl. Phys., vol. 55, no. 6, 067302 (2016).

We investigated the fundamental aspects of droplet dispensing, which is an important procedure in the noncontact ultrasonic manipulation of droplets in air. A holed reflector was used to dispense a droplet from a 27.4 kHz standing-wave acoustic field to a well. First, the relationship between the hole diameter of the reflector and the acoustic radiation force acting on a levitated droplet was clarified by calculating the acoustic impedance of the point just above the hole. When the hole diameter was half of (or equal to) the acoustic wavelength λ, the acoustic radiation force was ~80% (or 50%) of that without a hole. The maximal diameters of droplets levitated above the holes through flat and half-cylindrical reflectors were then experimentally investigated. For instance, with the half-cylindrical reflector, the maximal diameter was 5.0 mm for a hole diameter of 6.0 mm, and droplets were levitatable up to a hole diameter of 12 mm (~λ).