| Project/Area Number |
11308018
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Nuclear engineering
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| Research Institution | Nagoya University |
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Principal Investigator |
NAGASAKI Takanori Nagoya Univ. Grad. School of Eng. Associate Professor, 工学研究科, 助教授 (40273289)
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| Co-Investigator(Kenkyū-buntansha) |
SHIGEMATSU Hirokake Nagoya Univ. Grad. School of Eng. Assistant Professor, 工学研究科, 助手 (40281068)
ARITA Yuji Nagoya Univ. Grad. School of Eng. Associate Professor, 環境量子リサイクル研究センター, 助教授 (50262879)
MATSUI Tsuneo Nagoya Univ. Grad. School of Eng. Professor, 工学研究科, 教授 (90135319)
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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 |
¥30,240,000 (Direct Cost: ¥29,400,000、Indirect Cost: ¥840,000)
Fiscal Year 2001: ¥3,640,000 (Direct Cost: ¥2,800,000、Indirect Cost: ¥840,000)
Fiscal Year 2000: ¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 1999: ¥23,800,000 (Direct Cost: ¥23,800,000)
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| Keywords | thermoreflectance / thermalconduction / thermal diffusivity / radiation effect / lattice defect / pulse laser / 熱拡散率 / 熱反射法 |
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| Research Abstract |
We have developed an apparatus based on the transient thermoreflectance technique to measure the thermal diffusivity of thin surface layer of a bulk material as well as thin film on a thick substrate.
- We observed thermoreflectance signal for aluminum sheets, aluminum film, gold film, stainless steel sheets.
- Transient thermoreflectance for the aluminum sheets obeyed the parabolic one-step radiation heating model (POS model). This means that in aluminum, the electron-phonon thermalization time is much shorter than the measurement time scale so that a local equilibrium between electrons and phonons is achieved throughout the measurement. The thermal diffusivity determined by curve fitting was, however, not so reliable because of the undesirable property of the theoretical curve and the large thermal diffusivity of aluminum.
- Transient thermoreflectance for the gold film was much faster than that for the aluminum sheets. This is because the thermalization time in gold is comparable to the measurement time scale; for a few picoseconds after pulse heating, the electron temperature is higher than the lattice temperature. It is cooling of the sample surface due to the relaxation of and/or heat transfer by these non-equilibrium electrons that was detected as transient thermoreflectance.
- Transient thermoreflectance for the stainless steel sheets was basically described by the POS model. The thermal diffusivities determined were an order of magnitude smaller than those of aluminum.
- We tried to measure the thermal diffusivity of an aluminum sheet irradiated by 2 MeV He ions. Although the degradation due to the irradiation was not clear in this sample, we believe the apparatus itself is applicable to determine the thermal diffusivity of ion-irradiated materials. We are trying to measure the thermal diffusivity of heavily irradiated materials and will discuss the radiation effect on thermal conduction in solids.
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