Possibilities of nondestructive evaluation of a pipe using air-coupled ultrasonic wave in the MHz range. - Kazuhiko Imano; Masaaki Kondou (IEICE Electron. Express, 2008)

Detecting pipe wall reduction using air-coupled MHz range ultrasonic wave. - Kazuhiko Imano; Masaaki Kondou (IEICE Electron. Express, 2009)