2007 Fiscal Year Final Research Report Summary
Generation mechanism of in-liquid plasma and its inner structure
| Project/Area Number |
18560202
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Thermal engineering
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| Research Institution | Ehime University |
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Principal Investigator |
NOMURA Shinfuku Ehime University, Graduate School of Science and Engineering, Professor (20263957)
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| Co-Investigator(Kenkyū-buntansha) |
TOYOTA Hiromichi Ehime University, Graduate School of Science and Engineering, Associate professor (00217572)
YAMASHITA Hiroshi Ehime university, Graduate School of Science and Engineering, Associate Professor (00182501)
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| Project Period (FY) |
2006 – 2007
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| Keywords | thermal Engineering / plasma arc machining / plasma・nuclear fusion / fluid engineering / plasma process |
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| Research Abstract |
The in-liquid plasma was generated by applying micowave radiation of 2.45GHz or high-frewuency irradiation of 27.12MHz. The temperature of a plasma generated by HF irradiation was higher than that generated by MW irradiation when the same electric power was applied to water. When the system pressure was increased from 100 hPa to 1013 hPa, the temperature of an in-liquid plasma in water generated by 2.45-GHz irradiation dropped from 4000 K to 3500 K, while that at 27.12 MHz dropped from 5000 K to about 4000 K. The plasma temperature in water flow also dropped from 4700 K to about 4400 K when the pressure decreased from 400 hPa to 100 hPa. The in-liquid plasma is generated in bubbles in the liquid. To clarify the generation mechanisum of in-liquid plasma and basic characteristics, the photography of the behavior of the plasma and bubbles was performed using a high-speed camera. The plasma repeatedly expanded and contracted in the same bubble until the departure of the bubble from the electrode. The discharge conformation of in-liquid plasma in water will evolve into the form of a steamer discharge like the observed corona discharge from a conventional needle-like electrode. The plasma electron density is calculated from the half-width of H_β line. The estimated electron density is (6.0±2.0) x10^<14>cm^<-3> at 27.12 MHz and (7.2±2.0) x10^<14>cm^<-3> at 2.45 GHz. The OH rotational temperature is about 3000 K. The non-equilibrium plasma can be maintained in spite of high pressure codttion due to the cooling effect by the cooling effect from the evaporation of the liquid itself. Finally, a supercritical carbon dioxide (CO2) plasma process for fabricating one-dimensional tungsten oxide nanowires coated with amorphous carbon was presented.
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Research Products
(20 results)
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[Journal Article] Discharge Characteristics of MW and HF In-liquid Plasma in Water2008
Author(s)
Shinfuku, Nomura, Hiromichi, Toyota, Shinobu, Mukasa, Yoshiyuki, Takahashi, Tunehiro, Maehara, Ayato, Kawashima, Hiroshi, Yamashita
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Journal Title
Applied Physics Express Vol.1 No.4
Pages: 046002-1-046002-3
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] 27.12 MHz plasma generation in supercritical carbon dioxide2007
Author(s)
Ayato, Kawashima, Hiromichi, Toyota, Shinfuku, Nomura, Toshihiko, Takemori, Shinobu, Mukasa, Tunehiro, Maehara, Hiroshi, Yamashita
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Journal Title
Journal of Applied Physics Vol.101 Issue.9
Pages: 093303-1-093303-4
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] A supercritical carbon dioxide plasma process for preparing tungsten oxide nanowires2007
Author(s)
Ayato, Kawashima, Shinfuku, Nomura, Hiromichi, Toyota, Toshihiko, Takemori, Shinobu, Mukasa, Tunehiro, Maehara
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Journal Title
NANOTECHNOLOGY Vol.18 No.49
Pages: 495603-1-495603-3
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Microwave plasma in hydrocarbon liquids2006
Author(s)
Shinfuku, Nomura, Hiromichi, Toyota, Shinobu, Mukasa, Hiroshi, Yamashita, Tsunehiro, Maehara, Makoto, Kuramoto
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Journal Title
Applied Physics Letters Vol.88
Pages: 211503-1-211503-3
Description
「研究成果報告書概要(欧文)」より
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[Presentation] High Frequency and Microwave Plasma in Water2007
Author(s)
Shinfuku, Nomura, Hiromichi, Toyota, Shinobu, Mukasa, Tsunehiro, Maehara, Yoshiyuki, Takahashi, Hiroshi, Itami
Organizer
Proceedings of the ASME-JSME 2007 Thermal Engineering and Summer Heat Transfer Conference
Place of Presentation
Vancouver, BC, Canada
Year and Date
20070407-10
Description
「研究成果報告書概要(欧文)」より
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