Direct Measurement of the Internal Pressure of Ultrafine Bubbles Using Radioactive Nuclei. - Tanigaki, Minoru; Yamakura, Takuya; Hayashi, Daiju; Ueda, Yoshikatsu; Taniguchi, Akihiro; Ohkubo, Yoshitaka; Tokuda, Yomei (Chemical Engineering & Technology, 2023)