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Nagao, Keisuke*; Okazaki, Ryuji*; Nakamura, Tomoki*; Miura, Yayoi*; Osawa, Takahito; Bajo, Kenichi*; Matsuda, Shintaro*; Ebihara, Mitsuru*; Ireland, T.*; Kitajima, Fumio*; et al.
Science, 333(6046), p.1128 - 1131, 2011/08
Times Cited Count：130 Percentile：95.22(Multidisciplinary Sciences)A steroid surface materials record regolith processes and a history of cosmic-ray irradiation. Noble gas isotopes in three rocky grains from Itokawa have been determined. High concentrations of solar He, Ne, and Ar, as high as those in lunar soils, are released at variable temperatures from each sample. The isotopic compositions are essentially identical to those of solar wind but distinguishable in He relative abundance. These noble gas characteristics can be explained by repeated implantation and preferential loss of solar He by removal of weathered He-rich rim on the grain surface through friction among regolith grains on Itokawa. Residence time of regolith materials on Itokawa is alculated to be shorter than 10 Myr, suggesting that regolith materials of small asteroids would escape easily to space.
Shimada, Yukihiro; Nishimura, Akihiko; Suzuki, Hirokazu*; Ishibashi, Hisayoshi*; Kawahara, Hirotaka; Ito, Chikara; Aoyama, Takafumi
no journal, ,
We developed the fiber Bragg grating (FBG) sensor system with high temperature tolerance for a deterioration evaluation of passing year and seismic safety in nuclear power plant. We examined the heating tolerance and the load transformation of the reinforced FBG sensor system. As a result, the strengthening FBG sensor was an excellent adhesion performance in the environment of 400 
C or less. Additionally, the load transformation examination was executed under the high temperature environment, and it was confirmed that the measurement of the amount of the transformation was possible with strengthening FBG sensor.
Shimada, Yukihiro; Nishimura, Akihiko; Suzuki, Hirokazu*; Ishibashi, Hisayoshi*; Kawahara, Hirotaka; Ito, Chikara; Aoyama, Takafumi
no journal, ,
no abstracts in English
Shimada, Yukihiro; Yonemoto, Yukihiro; Nishimura, Akihiko; Suzuki, Hirokazu*; Ishibashi, Hisayoshi*; Kawahara, Hirotaka; Ito, Chikara; Yoshida, Akihiro
no journal, ,
no abstracts in English
Shimada, Yukihiro; Nishimura, Akihiko; Suzuki, Hirokazu*; Ishibashi, Hisayoshi*
no journal, ,
A fiber Bragg grating (FBG) sensor with heat resistance was produced via a point microfabrication technique using a femtosecond pulse laser. The FBG sensor was reinforced by weaving with a carbon fiber tape. As a result, both high strength and a structure for mounting the sensor were readily incorporated. In a high-temperature tolerance evaluation of the FBG sensor, the temperature and strain were measured by the sensor at 600 degree C. Therefore, the sensor is effective, and in addition, the problems associated with mounting the sensor on high-temperature piping have been eliminated.
Shimada, Yukihiro; Nishimura, Akihiko; Suzuki, Hirokazu*; Ishibashi, Hisayoshi*; Ito, Keisuke; Ito, Chikara; Yoshida, Akihiro
no journal, ,
A Fiber Bragg Grating (FBG) sensor with heat resistance was produced via a point microfabrication technique using a femtosecond pulse laser. It can be used as temperature or a strain sensor by measuring change of the reflective wavelength of FBG. Heating test under operational temperature of Fast Reactors is now planed. This time, we did the withstand type test on the sensor by using the piping material in the environment of 400 degrees. As a result, it succeeded in a small oscillation and measuring a strain. The heat-resistant FBG sensor developed using ultra-short pulse laser processing will contribute to the surveillance of power plants for seismic safety.
