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Your search keyword '"Isayama, A."' showing total 67 results
Start Over Author "Isayama, A." Publication Type Conference Materials
67 results on '"Isayama, A."'

6. Development of high-contrast developing for nuclear emulsion film for GRAINE experiment

Author

Yamamoto, Saya, primary, Isayama, Yudai, additional, Usuda, Ikuya, additional, Nakamura, Tomoaki, additional, Nakamura, Yuya, additional, Minami, Hideyuki, additional, Rokujo, Hiroki, additional, Nakamura, Mitsuhiro, additional, Nakano, Toshiyuki, additional, Aoki, Shigeki, additional, Takahashi, Satoru, additional, Nagahara, Shogo, additional, Oda, Miyuki, additional, Kato, Takumi, additional, Yamashita, Mayu, additional, Okamoto, Kazuhiro, additional, Yoneno, Shoma, additional, Kodama, Koichi, additional, Nakazawa, Kazuma, additional, Iyono, Atsushi, additional, Akita, Shoto, additional, and Murakami, Fumiya, additional

Published
2023
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8. Nuclear emulsion detector for large-area, high-angular-resolution gamma-ray telescope

Author

Rokujo, Hiroki, primary, Akita, Shoto, additional, Isayama, Yudai, additional, Iyono, Atsushi, additional, Komatsu, Masahiro, additional, Nakano, Toshiyuki, additional, Nakamura, Tomoaki, additional, Nakamura, Mitsuhiro, additional, Nakamura, Yuya, additional, Minami, Hideyuki, additional, Sato, Osamu, additional, Sugimura, Kou, additional, Usuda, Ikuya, additional, and Yamamoto, Saya, additional

Published
2023
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16. 14-3-3γ Protein: A Novel Serum Biomarker for Predicting Prognosis in Idiopathic Pulmonary Fibrosis

Author

Hozumi, H., primary, Isayama, T., additional, Okada, J., additional, Sugiura, K., additional, Yasui, H., additional, Suzuki, Y., additional, Kono, M., additional, Karayama, M., additional, Furuhashi, K., additional, Enomoto, N., additional, Fujisawa, T., additional, Inui, N., additional, Nakamura, Y., additional, Hayakawa, H., additional, and Suda, T., additional

Published
2020
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20. Progress and status of the gyrotron development for the JT-60SA ECH/CD system

Author

Kobayashi, T., primary, Sawahata, M., additional, Terakado, M., additional, Hiranai, S., additional, Ikeda, R., additional, Oda, Y., additional, Wada, K., additional, Hinata, J., additional, Yokokura, K., additional, Hoshino, K., additional, Takahashi, K., additional, Isayama, A., additional, Moriyama, S., additional, and Sakamoto, K., additional

Published
2015
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24. Optical Modeling and Physical Performances Evaluations for the JT-60SA ECRF Antenna.

Author

Platania, P., Figini, L., Farina, D., Isayama, A., Kobayashi, T., Micheletti, D., Moriyama, S., Moro, A., and Sozzi, C.

Subjects
ANTENNAS in plasma, NUCLEAR optical models, ELECTROMAGNETISM, SIMULATION methods & models, CURRENT-drive heating
Abstract

The purpose of this work is the optical modeling and physical performances evaluations of the JT-60SA ECRF launcher system. The beams have been simulated with the electromagnetic code GRASP? and used as input for ECCD calculations performed with the beam tracing code GRAY, capable of modeling propagation, absorption and current drive of an EC Gaussion beam with general astigmatism. Full details of the optical analysis has been taken into account to model the launched beams. Inductive and advanced reference scenarios has been analysed for physical evaluations in the full poloidal and toroidal steering ranges for two slightly different layouts of the launcher system. [ABSTRACT FROM AUTHOR]

Published
2015
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25. Research and Development of 2-frequency (110/138 GHz) FADIS for JT-60SA ECHCD system.

Author

Idei, H., Moriyama, S., Kobayashi, T., Isayama, A., Sakaguchi, M., and Kasparek, W.

Subjects
GYROTRONS, ELECTRON cyclotron resonance heating, ELECTRON cyclotron resonance sources
Abstract

A FAst DIrectional Switch (FADIS) of 2-frequency (2-f) gyrotron system for the JT-60SA project is being developed under collaboration between Japan Atomic Energy Agency (JAEA) and Kyushu University. At first, the frequency drift and dip in the gyrotron operation were measured to consider which kind of FADIS is preferred for application in the Electron Cyclotron Heating and Current Drive (ECHCD) system for the JT-60SA. Various types of the FADIS have been considered. A square corrugated waveguide diplexer system with double resonant rings was considered as one of the most attractive FADIS systems for stable high-power and long-pulse operations in the 2-f JT-60SA ECHCD system. [ABSTRACT FROM AUTHOR]

Published
2015
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26. Development of a dual frequency (110/138 GHz) gyrotron for JT-60SA and its extension to an oscillation at 82 GHz.

Author

Takayuki Kobayashi, Shinichi Moriyama, Akihiko Isayama, Masayuki Sawahata, Masayuki Terakado, Shinichi Hiranai, Kenji Wada, Yoshikatsu Sato, Jun Hinata, Kenji Yokokura, Katsumichi Hoshino, and Keishi Sakamoto

Subjects
GYROTRONS, ELECTROMAGNETIC waves, ELECTRON cyclotron resonance heating, ELECTRON cyclotron resonance sources, OSCILLATIONS
Abstract

A dual-frequency gyrotron, which can generate 110 GHz and 138 GHz waves independently, is being developed in JAEA to enable electron cyclotron heating (ECH) and current drive (ECCD) in a wider range of plasma discharge conditions of JT-60SA. Conditioning operation of the gyrotron toward 1 MW for 100 s, which is the target output power and pulse length for JT-60SA, is in progress without significant problems. Oscillations of 1 MW for 10 s and 0.5 MW for 198 s were obtained, so far, at both frequencies. Cooling water temperatures in the gyrotron and matching optics unit were saturated in the 198 s oscillation, and the observed maximum water temperature is sufficiently low. In addition to the above activity on the dualfrequency gyrotron development, an oscillation (0.3 MW for 20 ms) at 82 GHz was demonstrated as an additional frequency of the dual-frequency gyrotron. A possibility of the use of fundamental harmonic wave at 82 GHz in JT-60SA has been shown. [ABSTRACT FROM AUTHOR]

Published
2015
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28. Dual frequency gyrotron development for JT-60SA

Author

Kobayashi, T., primary, Isayama, A., additional, Sawahata, M., additional, Suzuki, S., additional, Terakado, M., additional, Hiranai, S., additional, Wada, K., additional, Sato, Y., additional, Hinata, J., additional, Yokokura, K., additional, Hoshino, K., additional, Kajiwara, K., additional, Sakamoto, K., additional, and Moriyama, S., additional

Published
2012
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30. Abstract B27: Erlotinib prolongs survival in pancreatic cancer by blocking gemcitabine-induced mitogen-activated protein kinase signal.

Author

Miyabayashi, Koji, primary, Isayama, Hiroyuki, additional, Omata, Masao, additional, Moses, Harold L., additional, Koike, Kazuhiko, additional, Ijichi, Hideaki, additional, Mohri, Dai, additional, Tada, Motohisa, additional, Yamamoto, Keisuke, additional, Asaoka, Yoshinari, additional, Ikenoue, Tsuneo, additional, Tateishi, Keisuke, additional, and Nakai, Yousuke, additional

Published
2012
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41. Recent Results in Large Helical Device

Author

Nagayama, Y., primary, Ikeda, K., additional, Komori, A., additional, Kumazawa, R., additional, Morita, S., additional, Ohyabu, N., additional, Peterson, B.J., additional, Sakakibara, S., additional, Shimozuma, T., additional, Yamada, H., additional, Ashikawa, N., additional, Chikaraishi, H., additional, Emoto, M., additional, Funaba, H., additional, Goncharov, P., additional, Goto, M., additional, Hamada, Y., additional, Ida, K., additional, Ido, T., additional, Igami, H., additional, Imagawa, S., additional, Inagaki, S., additional, Isayama, A., additional, Isobe, M., additional, Iwamoto, A., additional, Kaneko, O., additional, Kawahata, K., additional, Kobuchi, T., additional, Kogi, Y., additional, Kubo, S., additional, Mase, A., additional, Masuzaki, S., additional, Matsuoka, K., additional, Minami, T., additional, Mito, T., additional, Miyazawa, J., additional, Morisaki, T., additional, Murakami, S., additional, Muto, S., additional, Mutoh, T., additional, Nakamura, Y., additional, Nakanishi, H., additional, Narihara, K., additional, Narushima, Y., additional, Nishimura, A., additional, Nishimura, K., additional, Nishizawa, A., additional, Noda, N., additional, Notake, T., additional, Nozato, H., additional, Ohdachi, S., additional, Oka, Y., additional, Osakabe, M., additional, Okajima, S., additional, Ozaki, T., additional, Sagara, A., additional, Saito, K., additional, Sakamoto, M., additional, Sakamoto, R., additional, Sasao, M., additional, Sato, K., additional, Seki, T., additional, Shoji, M., additional, Sudo, S., additional, Suzuki, H., additional, Takahata, K., additional, Takeiri, Y., additional, Takenaga, H., additional, Tamura, N., additional, Tanaka, K., additional, Toi, K., additional, Tokuzawa, T., additional, Torii, Y., additional, Tsumori, K., additional, Uda, T., additional, Watanabe, K. Y., additional, Yamada, I., additional, Yamazaki, K., additional, Yanagi, N., additional, Yokoyama, M., additional, Yoshimura, Y., additional, Yoshinuma, Y., additional, Watari, T., additional, and Motojima, O., additional

Published
2005
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42. ECH and ECCD effects on NTMs stabilization by ECRF in JT- 60SA tokamak.

Author

Sozzi, C., Bolzonella, T., Farina, D., Figini, L., Furukawa, M., Giruzzi, G., Ide, S., Isayama, A., Matsunaga, G., Moriyama, S., and Nowak, S.

Subjects
RADIO frequency, ELECTRON cyclotron resonance sources, CYCLOTRONS, AUTOMATIC control systems, RADIO frequency modulation
Abstract

The current drive efficiency of the dual frequency (110 GHz and 138 GHz) ECRF system of JT-60SA is studied. The requirements for neoclassical tearing modes (NTMs) instabilities control by ECRF during the initial research phase when only part of the full system will be available are discussed. [ABSTRACT FROM AUTHOR]

Published
2012
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45. Development of a Real-time Modulation Control System on the JT-60U ECRF System.

Author

Kobayashi, T., Isayama, A., Terakado, M., Sato, F., Suzuki, S., Hiranai, S., Shibayama, M., and Moriyama, S.

Subjects
RADIO frequency modulation, ELECTRONS, CYCLOTRONS, PARTICLES (Nuclear physics), GYROTRONS, OSCILLATIONS
Abstract

A real-time modulation control system was developed for studying the effectiveness of modulated Electron Cyclotron Current Drive (ECCD) on the stabilization of Neoclassical Tearing Modes (NTMs). The phase and duty cycle tracking was enabled with high accuracy even if the NTM frequency varied during ECCD. A characteristic of an anode voltage modulation for modulating the gyrotron oscillation that caused the time variation of the phase and duty cycle was also taking into account. It was shown that the phase and duty cycle could be kept the target values within 50 ms even if the frequency varied by 1 kHz/s or higher at a frequency of around 5 kHz. Then, NTM stabilization experiments with modulated ECCD for m/n = 2/1 NTM was successfully performed in JT-60U. [ABSTRACT FROM AUTHOR]

Published
2009
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46. Control of Current Profile and Instability by Radiofrequency Wave Injection in JT-60U and Its Applicability in JT-60SA.

Author

Isayama, A., Suzuki, T., Hayashi, N., Ide, S., Hamamatsu, K., Fujita, T., Hosoyama, H., Kamada, Y., Nagasaki, K., Oyama, N., Ozeki, T., Sakata, S., Seki, M., Sueoka, M., Takechi, M., and Urano, H.

Subjects
ELECTROOPTICS, RADIO frequency, STARK effect, COMPUTER simulation, AUTOMATIC control systems
Abstract

Recent results of control of current profile and instability using radiofrequency wave in JT-60U and prediction analysis in JT-60SA are descried. In JT-60U, control of current profile in high-beta regime was demonstrated by using a real-time system, where the motional Stark effect diagnostic and lower hybrid wave were used as a detector and actuator, respectively. The minimum value of the safety factor was raised from 1.3 to 1.7 so as to follow the commanded value. Complete stabilization of a neoclassical tearing mode (NTM) with the poloidal mode number m = 2 and the toroidal mode number n = 1 was demonstrated using electron cyclotron (EC) current drive. By scanning the location of EC current drive in detail, strong stabilization effect was found for misalignment less than about half of the full island width. In addition, destabilization of the 2/1 NTM was observed for misalignment comparable to the full island width. Simulation of NTM stabilization in JT-60SA was performed by using the TOPICS code combined with the modified Rutherford equation. The TOPICS simulation showed that complete stabilization can be achieved more effectively by optimizing the EC wave injection angle and modulating the EC wave. [ABSTRACT FROM AUTHOR]

Published
2007
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47. Recent RF Experiments and Application of RF Waves to Real-Time Control of Safety Factor Profile in JT-60U.

Author

Suzuki, T., Isayama, A., Ide, S., Fujita, T., Oikawa, T., Sakata, S., Sueoka, M., Hosoyama, H., and Seki, M.

Subjects
RADIO frequency, REAL-time control, SPECTRUM analysis, STARK effect, ELECTROMAGNETIC fields, REFRACTIVE index
Abstract

Two topics of applications of RF waves to current profile control in JT-60U are presented; application of lower-hybrid (LH) waves to safety factor profile control and electron cyclotron (EC) waves to neo-classical tearing mode (NTM) control. A real-time control system of safety factor (q) profile was developed. This system, for the first time, enables 1) real time evaluation of q profile using local magnetic pitch angle measurement by motional Stark effect (MSE) diagnostic and 2) control of current drive (CD) location (ρCD) by controlling the parallel refractive index N∥ of LH waves through control of phase difference (Δ[lowercase_phi_synonym]) of LH waves between multi-junction launcher modules. The method for real-time q profile evaluation was newly developed, without time-consuming reconstruction of equilibrium, so that the method requires less computational time. Safety factor profile by the real-time calculation agrees well with that by equilibrium reconstruction with MSE. The control system controls ρCD through Δ[lowercase_phi_synonym] in such a way to decrease the largest residual between the real-time evaluated q profile q(r) and its reference profile qref(r). The real-time control system was applied to a positive shear plasma (q(0)∼1). The reference q profile was set to monotonic positive shear profile having qref(0)=1.3. The real-time q profile approached to the qref(r) during application of real-time control, and was sustained for 3s, which was limited by the duration of the injected LH power. Temporal evolution of current profile was consistent with relaxation of inductive electric field induced by theoretical LH driven current. An m/n=3/2 NTM that appeared at βN∼3 was completely stabilized by ECCD applied to a fully-developed NTM. Precise ECCD at NTM island was essential for the stabilization. ECCD that was applied to resonant rational surface (q=3/2) before an NTM onset suppressed appearance of NTM. In order to keep NTM intensity below a level, ECCD before the mode onset was more effective than that after mode saturation. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Published
2005
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49. Recent progress in the 110GHz ECRF system on JT-60U tokamak.

Author

Ikeda, Y., Seki, M., Moriyama, S., Kajiwara, K., Anno, K., Hiranai, S., Ikagarshi, K., Isaka, M., Isayama, A., Imai, T., Sakamoto, K., Sato, H., Shimono, M., Shinozaki, S., Takahashi, M., Terakado, M., Yokokura, K., and Fujii, T.

Subjects
GYROTRONS, WAVEGUIDES, MAGNETOHYDRODYNAMICS, TOKAMAKS, ELECTRIC power
Published
2003

50. Formation of high electron temperature plasmas in ECH experiments on JT-60U tokamak.

Author

Ikeda, Y., Suzuki, T., Isayama, A., Kajiwara, K., Ide, S., Ozeki, T., Moriyama, S., Seki, M., Fujita, T., Takechi, M., Koide, Y., Fukuda, T., Takenaga, H., Naito, O., Hamamatsu, K., Hatae, T., and Fujii, T.

Subjects
ELECTRON temperature, PLASMA gases, ELECTRON cyclotron resonance heating, TOKAMAKS, FUSION reactors
Published
2003

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