Crystal structure and magnetic properties of new ternary uranium compound UTiBi

Motoyama, Gaku*; Haga, Yoshinori; Yamaguchi, Akira*; Kawasaki, Ikuto*; Sumiyama, Akihiko*; Yamamura, Tomoo*

Progress in Nuclear Science and Technology (Internet), 5, p.157 - 160, 2018/11

https://doi.org/10.15669/pnst.5.157

Development of a high power wideband polarizer for electron cyclotron current drive system in JT-60SA

Saigusa, Mikio*; Oyama, Gaku*; Matsubara, Fumiaki*; Takii, Keita*; Sai, Takuma*; Kobayashi, Takayuki; Moriyama, Shinichi

Fusion Engineering and Design, 96-97, p.577 - 582, 2015/10

https://doi.org/10.1016/j.fusengdes.2015.04.013

A wideband polarizer has been developed for an ECCD system in JT-60SA. The groove depth of the mirrors installed in miter bends were optimized for two frequencies (110 GHz and 138 GHz) by numerical simulations. All surfaces of Poincare spheres were covered at both of the frequencies in low power test. The thermal stress of polarizer were estimated by the numerical simulations. The twister polarizer has been tested up to 0.24 MW during 3 s at 110 GHz.

Josephson effect between UPt and conventional superconductors under pressure

Gochi, Jun*; Sumiyama, Akihiko*; Yamaguchi, Akira*; Motoyama, Gaku*; Kimura, Noriaki*; Yamamoto, Etsuji; Haga, Yoshinori; Onuki, Yoshichika

JPS Conference Proceedings (Internet), 3, p.011067_1 - 011067_6, 2014/06

https://doi.org/10.7566/JPSCP.3.011067

Research and development of high power wide-band polarizer for ECCD system in JT-60SA

Sugiyama, Naoya*; Oyama, Gaku*; Matsubara, Fumiaki*; Saigusa, Mikio*; Isayama, Akihiko; Kobayashi, Takayuki; Moriyama, Shinichi

no journal, , 

The development status of a wide-band polarizer for ECCD system in JT-60SA is reported. The polarizer was designed at the frequency bands of 110, 130 and 140 GHz based on the simulation results with the finite differential time domain (FDTD) method. The properties of polarizer have been measured with low power test at both of the frequency bands of 110 GHz and 138 GHz. In future work, it is necessary to draw the Poincare sphere based on an experimental result, and to optimize the depth of the grooved mirrors. After that, the wide-band polarizer with a cooling system will be designed, fabricated and tested at high power up to 1 MW.

Research and development of high power wideband polarizer for ECCD system in JT-60SA

Oyama, Gaku*; Sugiyama, Naoya*; Matsubara, Fumiaki*; Saigusa, Mikio*; Kobayashi, Takayuki; Isayama, Akihiko; Moriyama, Shinichi

no journal, , 

no abstracts in English

Yakedake Nakao tephra; An Attempt to use the local tephra as a Late Holocene age marker for the southern part of the Northern Japan Alps

Nishio, Gaku*; Kagami, Saya; Yokoyama, Tatsunori; Kariya, Yoshihiko*; Kojima, Satoru*

no journal, , 

We attempt to use local tephra derived from nearby volcanoes as an age marker. The Kamikochi area in the southern part of the Northern Alps is strongly affected by the Yakedake volcano. We prepared distinctive tephras, (1) one sample of glassy volcanic ash in hand auger boring cores drilled at the near-shore Kinugasanoike Pond, about 4.7 km northeast of Mt. Yakedake and (2) two samples of glassy volcanic ash in the Nakao pyroclastic flow deposites, which is considered to be a product of the last magmatic eruption about 2,300 years ago, distributed about 1.5 km north-northwest of Mt. Yakedake. We investigated the clast composition of these tephras and the chemical composition and refractive index of volcanic glass. Approximately 70% of the clasts were volcanic glasses, and most of them were vesicular and blocky types. These glasses were characterized by high SiO, KO, NaO and low AlO, FeO, which were clearly distinguishable from the volcanic glasses in Quaternary widespread tephras. The refractive indices of 30 volcanic glasses for each tephra were 1.4958-1.5011 with a peak in the range of 1.497 to 1.499. The results of this study indicate the tephra from Kinugasanoike Pond were erupted from Mt. Yakedake about 2,300 years ago. Therefore, the tephra with the above characteristics can be used as a useful age marker for the southern part of the Northern Alps about 2,300 years ago.