Studies on ultra fine bubbles by using techniques on nuclear physics

2022 Fiscal Year Final Research Report

• Project/Area Number: 18K03948
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 19010:Fluid engineering-related
• Research Institution: Kyoto University
• Principal Investigator: Minoru Tanigaki 京都大学, 複合原子力科学研究所, 助教 (90314294)
• Project Period (FY): 2018-04-01 – 2023-03-31
• Keywords: ウルトラファインバブル / 内部圧力 / γ線放出非対称度 / 超微細相互作用 / 不安定核

Outline of Final Research Achievements

Direct measurement of the internal pressures of ultrafine bubbles of Xe gas was successfully performed using the known pressure dependence of the degree of the γ-ray asymmetry of radioiodine in Xe gas. Iodine-125 was induced inside bubbles by thermal neutron irradiation. The obtained pressure was lower than predicted by the Young-Laplace equation, which was well-established for conventional bubbles. The present result strongly suggests the existence of some pressure-compensation mechanism. The interaction between hydrated ions of indium and ultrafine bubbles was also observed by the perturbed angular correlation method. A possible difference was observed around pH=10, suggesting the interaction of ultrafine bubbles with hydrated ions.

Free Research Field

原子核物理・核物性

Academic Significance and Societal Importance of the Research Achievements

ウルトラファインバブルの持つ高い機能性は産業界の幅広い分野で注目され応用が進んでいるものの、基礎特性や機能発現のメカニズムについては、従来の気泡研究で用いられた観測手法の適用が困難になることから十分進んでいなかった。今回の研究はウルトラファインバブルの新たな研究手法を提示しただけでもなく、基礎特性の理解につながる成果でもある。基礎特性の理解が進むことで、ウルトラファインバブルの機能性の活用の原理的裏付けやより適切な活用方法の確立につながる。