14 高濃度アルカリ塩水溶液中におけるソノルミネッセンス気泡の挙動(ソノケミストリーの基礎科学)

抄録

Single sonoluminescing bubble dynamics in high concentrated aqueous alkaline halide solutions is studied using a high speed framing camera. We observed high intensity single bubble sonoluminescence(SBSL) from an unstable bubble under higher acoustic pressure and concentration. In this condition, we got a photograph of bubbles split into a main sonoluminesing bubble and some daughter bubbles using a high speed framing camera. It is known that an unstable bubble comes from split daughter bubbles under lower acoustic pressure, but we got that under higher one. It is a new interesting phenomenon. The dynamics of a single sonoluminescing bubble in concentrated aqueous NaCl and KCl solutions under the range of 0.5 mol/l to 5 mol/l below saturation is studied using a high-speed framing camera. The luminescence intensity increased for higher acoustic pressures and higher concentrations, as expected, but remarkable increase was observed when the pressure was so high that the bubble motion became unstable. In this mode of dynamics, the bubble was splitting into a main sonoluminescing one and some daughter ones, as observed with the camera. Such unstable behavior is characteristic of the bubble dynamics around the lower sonoluminescience threshold for acoustic pressure, but our finding suggests that for dense aqueous solutions there exists another regime where the bubble is unstable but more luminous.