| Project/Area Number |
11650694
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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 |
Inorganic materials/Physical properties
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
YASUDA Kouichi Tokyo Institute of Technology, Faculty of Science and Engineering, Associate Professor, 大学院・理工学研究科, 助教授 (20191306)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUO Yohtaro Tokyo Institute of Technology, Faculty of Science and Engineering, Professor, 大学院・理工学研究科, 教授 (70016608)
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| Project Period (FY) |
1999 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2001: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2000: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1999: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | fracto-emission, photon emission, electron emission, fracture, ceramics / 光子放出 / 電子放出 / 破壊 / セラミックス / マグネシア / エネルギー分布 / アルミナ / MgO / Al_2O_3 |
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| Research Abstract |
Photon emission and electron emission were investigated during fracture of polycrystalline ceramics and their single crystals, and elementary processes of fracture in ceramics materials were discussed. The following conclusions were obtained.
(1) A notched specimen was fractured by 3-point bending test, and emitted photons and electrons were simultaneously detected.
(2) The peak count of photon | emission strongly depended on material, however, the order in the peak count could not be explained by the material characteristics.
(3) The grain size largely influenced the total count of photon emission of polycrystalline MgO and Al_2_3, because the photon emission was controlled by the crack extension process on grain size change.
(4) The photon emission showed crystal orientation dependence when MgO and Al_2_3 single crystals were fractured.
(5) The wavelength distribution measurements of the photon emission indicated that ultraviolet or purple light (and also yellow or orange light in some cases) was emitted at fracture and subsequently red or infrared light was emitted for about 200ms. From the result, the photon emission mechanism was proposed.
(6) At fracture, electron emission also showed the peak count corresponding to the photon emission. However, the distinct pre-emission of electrons was observed from the beginning of loading, which suggested that micro cracking occurred before fracture.
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