| Project/Area Number |
18K18821
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| Research Category |
Grant-in-Aid for Challenging Research (Exploratory)
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| Allocation Type | Multi-year Fund |
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| Review Section |
Medium-sized Section 19:Fluid engineering, thermal engineering, and related fields
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| Research Institution | Tohoku University |
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Principal Investigator |
SATO TAKEHIKO 東北大学, 流体科学研究所, 教授 (10302225)
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| Co-Investigator(Kenkyū-buntansha) |
上原 聡司 東北大学, 流体科学研究所, 助教 (70742394)
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| Project Period (FY) |
2018-06-29 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥5,980,000 (Direct Cost: ¥4,600,000、Indirect Cost: ¥1,380,000)
Fiscal Year 2019: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
Fiscal Year 2018: ¥3,770,000 (Direct Cost: ¥2,900,000、Indirect Cost: ¥870,000)
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| Keywords | 帯電 / 電荷輸送 / 気泡圧力 / 気泡収縮 / 気泡崩壊 / 最小気泡径 / 気泡 / 圧縮 / Ｘ線 / 気泡内圧力 / 数値解析 / X線 |
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| Outline of Final Research Achievements |
This study aimed at development of an X-ray generation method using high charge density at the time of collapse by charging plasma-induced bubbles. We validated the charge transport mechanism in a liquid which is essential for charge densification, and clarified the details of electric potential and delay time formed by escape of charges from the accumulated charged area. We also aimed at enhancement of charge density by using insulating oil. Comparing insulating oil and water, water has a higher shrink velocity at the time of collapse and a smaller minimum bubble diameter which is directly linked to densification. This result indicated that the charge accumulation in the bubble has the influence on the shrink velocity and the minimum bubble size. Also, based on the Paschen’s law, we newly developed a measurement method of the pressure inside the bubble which strongly affects the minimum bubble diameter at the time of collapse.
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| Academic Significance and Societal Importance of the Research Achievements |
本研究は，未だ十分に解明されていない液中の電荷輸送現象の一端を明らかにし，帯電気泡を収縮させ高電荷密度領域を形成する手法を提案した．レーザー誘起気泡の最大径時に気泡内で放電させ帯電し，気泡収縮を利用した高電荷密度化は世界でも初めての手法であり，生体の高解像度可視化に不可欠なX線発生源を極微小化の開発に資する研究で大きな社会的意義を有する．さらに，崩壊時の最小気泡径に大きな影響を与える気泡内圧力をパッシェンの法則を利用し新たに提案した．これは，キャビテーション研究で未知であった気泡内圧力情報を明らかにする手法であり，学術的意義は極めて大きい．
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