Harjo, S.; Kawasaki, Takuro; Tomota, Yo*; Gong, W.
Materials Science Forum, 905, p.46 - 51, 2017/08
Tomota, Yo*; Sato, Shigeo*; Uchida, M.*; Xu, P. G.; Harjo, S.; Gong, W.; Kawasaki, Takuro
Materials Science Forum, 905, p.25 - 30, 2017/08
Yokoseki, Takashi; Abe, Hiroshi; Makino, Takahiro; Onoda, Shinobu; Tanaka, Yuki*; Kandori, Mikio*; Yoshie, Toru*; Hijikata, Yasuto*; Oshima, Takeshi
Materials Science Forum, 821-823, p.705 - 708, 2015/07
Harjo, S.; Aizawa, Kazuya; Abe, Jun*; Gong, W.; Ito, Takayoshi*; Kawasaki, Takuro; Iwahashi, Takaaki
Materials Science Forum, 777, p.12 - 18, 2014/04
Umeda, Takahide*; Okamoto, Mitsuo*; Arai, Ryo*; Sato, Yoshihiro*; Kosugi, Ryoji*; Harada, Shinsuke*; Okumura, Hajime*; Makino, Takahiro; Oshima, Takeshi
Materials Science Forum, 778-780, p.414 - 417, 2014/02
Interface defects of Metal-Oxide-Semiconductors (MOSFETs) fabricated on Carbone (C) face 4H-SiC were investigated by Electrically Detected Magnet Resistance (EDMR). Gate oxide of the MOSFETs was formed by either wet-oxidation and H annealing or dry-oxidation. The values of channel mobility for MOSFETS with wet gate oxide and dry gate oxide are less than 1 and 90 cm/Vs, respectively. By EDMR measurement under low temperature (less than 20 K), EDMR signals related to C were detected. The peak height of the signals increased with increasing -ray doses, and the channel mobility decreased. From this result, it is assumed that hydrogen atoms passivating C dangling bonds are released by -rays and the channel mobility decreases with increasing the C related defects.
Suzuki, Hiroshi; Harjo, S.; Abe, Jun*; Akita, Koichi
Materials Science Forum, 777, p.105 - 111, 2014/02
Effects of beam divergence on pseudo-strains observed in time-of-flight (TOF) neutron diffraction, that overlapped with the neutron attenuation effect and the surface-effect were investigated. The through-surface strain scanning on an annealed steel plate was performed in different instrument resolutions by controlling the incident beam divergence. Typical pseudo-strain distributions were observed, but they showed different trend according to the beam divergence. Furthermore, it was demonstrated that the pseudo-strains induced in the strain scanning of coarse grain materials can be suppressed by controlling the incident beam divergence. Therefore, the incident beam divergence must be carefully considered to reduce pseudo-strains in time-of-flight neutron diffractometry.
Fujita, Natsuko; Iwamoto, Naoya; Onoda, Shinobu; Makino, Takahiro; Oshima, Takeshi
Materials Science Forum, 778-780, p.1042 - 1045, 2014/02
A Silicon Carbide (SiC) dosimeter has been exposed to -rays emitted from a Co source in order to test the response of radiation-induced current in the dose rate ranging from 0.4 Gy/h to 4 kGy/h. The SiC dosimeter in this study is a high purity semi-insulating 4H-SiC with nickel and aluminum electrode. The radiation-induced currents in the dosimeter show a linear relationship with the dose rate, and are repeatable and stable.
Harjo, S.; Hemmi, Tsutomu; Abe, Jun; Gong, W.; Nunoya, Yoshihiko; Aizawa, Kazuya; Ito, Takayoshi*; Koizumi, Norikiyo; Machiya, Shutaro*; Osamura, Kozo*
Materials Science Forum, 777, p.84 - 91, 2014/02
Abe, Jun*; Sekine, Kotaro*; Harjo, S.; Gong, W.; Aizawa, Kazuya
Materials Science Forum, 777, p.219 - 224, 2014/02
Deki, Manato*; Oka, Tomoki*; Takayoshi, Shodai*; Naoi, Yoshiki*; Makino, Takahiro; Oshima, Takeshi; Tomita, Takuro*
Materials Science Forum, 778-780, p.661 - 664, 2014/02
no abstracts in English
Iwamoto, Naoya; Onoda, Shinobu; Fujita, Natsuko; Makino, Takahiro; Oshima, Takeshi
Materials Science Forum, 778-780, p.289 - 292, 2014/02
Deki, Manato*; Makino, Takahiro; Kojima, Kazutoshi*; Tomita, Takuro*; Oshima, Takeshi
Materials Science Forum, 778-780, p.440 - 443, 2014/02
no abstracts in English
Suzuki, Kenji*; Shobu, Takahisa; Shiro, Ayumi; Zhang, S.*
Materials Science Forum, 777, p.155 - 160, 2014/02
Shibano, Junichi*; Kajiwara, Kentaro*; Tsukamoto, Takuya*; kawai, Hirokazu*; Miura, Setsuo*; Zhang, S.*; Shobu, Takahisa; Kobayashi, Michiaki*
Materials Science Forum, 777, p.176 - 181, 2014/02
Sano, Mutsumi*; Takahashi, Sunao*; Watanabe, Atsuo*; Shiro, Ayumi; Shobu, Takahisa
Materials Science Forum, 777, p.255 - 259, 2014/02
Klahold, W. M.*; Devaty, R. P.*; Choyke, W. J.*; Kawahara, Kotaro*; Kimoto, Tsunenobu*; Oshima, Takeshi
Materials Science Forum, 778-780, p.273 - 276, 2014/02
Miyake, Keiko*; Yasuda, Tomonari*; Kato, Masashi*; Ichimura, Masaya*; Hatayama, Tomoaki*; Oshima, Takeshi
Materials Science Forum, 778-780, p.503 - 506, 2014/02
Nakane, Hiroki*; Kato, Masashi*; Ichimura, Masaya*; Oshima, Takeshi
Materials Science Forum, 778-780, p.277 - 280, 2014/02
Suzuki, Hiroshi; Katsuyama, Jinya; Akita, Koichi
Materials Science Forum, 772, p.33 - 38, 2013/11
When measuring residual strain distributions of thick structural components such as thick butt-welds using neutron diffraction, it is required to make a gauge volume larger as well as to shorten neutron path length in a material to obtain sufficient diffraction intensity. In this study, neutron attenuation effect on the strain measurement with a large gauge volume was discussed on the normal strain measurement of a thick butt-weld. Influences of neutron attenuation like an apparent strain change were observed, and it was more noticeable when the gauge volume becomes larger. Therefore, the neutron attenuation effect should be considered in the strain measurement with a large gauge volume, and the neutron absorption corrections certainly play an important role for improvement of reliabilities of strain measurement using neutron diffraction with a large gauge volume.
Hirade, Tetsuya; Oka, Toshitaka; Morishita, Norio*; Idesaki, Akira; Shimada, Akihiko
Materials Science Forum, 733, p.151 - 154, 2013/00
Polyimide polymers such as Kapton show a very good performance at high radiation environment such as in space or in radiation facilities. Positron annihilation lifetime measurement is a widely used method for materials science, and the lifetime of triplet positronium (electron-positron pair) can give important information of free volume of polymers. However, there is no positronium formation in Kapton and hence this method was no applied for polymer studies. Here, we indicated that free positron annihilation lifetime can give information of change of free volume by showing the temperature dependence of the lifetime. We applied this method to study irradiation effects on Kapton and we successfully indicated that the free positron lifetime can be applied for polymer studies.