著者

James H.P. RICE Naoto TSUJII Yuichi TAKASE Akira EJIRI Osamu WATANABE Hibiki YAMAZAKI Yi PENG Kotaro IWASAKI Yuki AOI Yongtae KO Kyohei MATSUZAKI Yuki OSAWA

出版者

The Japan Society of Plasma Science and Nuclear Fusion Research

雑誌

Plasma and Fusion Research (ISSN:18806821)

巻号頁・発行日

vol.15, pp.2402009, 2020-04-06 (Released:2020-05-08)

参考文献数

13

被引用文献数

4

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A new Langmuir probe has been designed and installed in TST-2 for measurements of Scrape-Off Layer plasmas (SOL). Non-inductive current drive is considered essential for spherical tokamak reactors. It has previously been shown that a large amount of injected Lower Hybrid Wave (LHW) power is lost in the SOL [1]. A full density profile of SOL conditions is necessary to accurately simulate the propagation of LHW in TST-2. A new probe was designed for durability, larger signal and Mach probe measurements. The new probe has been installed in TST-2 and results have been obtained. Temperature measurements show Te = 30 - 50 eV during RF injection and <10 eV otherwise. Density measurements show ne = 2.0 × 1015 m−3 and 1.5 × 1016 m−3 during flat-top RF power injection from Outboard- and Top-launch antennas, respectively. This is above the cut-off density for the 200 MHz LHW (5 × 1014 m−3) in TST-2, thus LHW can propagate through SOL plasma.

著者

Naoto TSUJII Yusuke YOSHIDA Yuichi TAKASE Akira EJIRI Osamu WATANABE Hibiki YAMAZAKI Yi PENG Kotaro IWASAKI Yuki AOI Yongtae KO Kyohei MATSUZAKI James H.P. RICE Yuki OSAWA

出版者

The Japan Society of Plasma Science and Nuclear Fusion Research

雑誌

Plasma and Fusion Research (ISSN:18806821)

巻号頁・発行日

vol.15, pp.2402010, 2020-04-06 (Released:2020-05-08)

参考文献数

13

被引用文献数

2 4

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Removal of the central solenoid is considered essential to realize a spherical tokamak fusion reactor, but non-inductive plasma start-up is a challenge. Start-up using lower-hybrid (LH) waves has been studied on the TST-2 spherical tokamak at the University of Tokyo. The equilibrium poloidal field is believed to be generated mostly by the wave driven fast electrons, which are highly non-thermal and have large orbit excursions from the flux surfaces due to low plasma current. Such an equilibrium can be qualitatively different from the Grad-Shafranov equilibrium routinely used for internal magnetic field reconstruction in a tokamak. In this work, the effect of fast electrons on the MHD equilibrium was investigated by considering the equilibrium solution of the hybrid-MHD model [Y. Todo and A. Bierwage, Plasma Fusion Res. 9, 3403068]. The fast electron distribution function was estimated using a LH current drive simulation based on ray-tracing and an orbit-averaged Fokker-Planck solver. The equilibrium solution of the hybrid-MHD model was successfully fitted to the magnetic and kinetic measurements. The resulting poloidal flux function was more skewed towards the outboard side when fast electrons were introduced, which was more consistent with the density profile measured by the Thomson scattering diagnostic.

著者

Xi Ding Yang Zhao Chun-Ying Zhu Li-Ping Wu Yue Wang Zhao-Yi Peng Cuomu Deji Feng-Yi Zhao Bing-Yin Shi

出版者

The Japan Endocrine Society

雑誌

Endocrine Journal (ISSN:09188959)

巻号頁・発行日

pp.EJ20-0796, (Released:2021-04-21)

被引用文献数

19

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The association between subclinical hypothyroidism (SCH) and metabolic syndrome (MetS) has been widely discussed. This study aimed to conduct an update and comprehensive meta-analysis to reveal the risk of MetS and its components in SCH. PubMed, Embase and ISI Web of Knowledge were searched to identify relevant studies through February 20th, 2020. Review Manager 5.3 and Stata 14.0 were used to conduct the meta-analysis. Both fixed-effects and random-effects models were used. In total, 18 articles (19 studies) incorporating 79,727 participants were included. The pooled OR for MetS comparing subjects with SCH with euthyroid subjects was 1.28 (95% CI: 1.19 to 1.39, p = 0.04, I2 = 40%). Subgroup analysis results showed significant associations of SCH and MetS in the adult subgroup (OR = 1.28, 95% CI: 1.18–1.40), Asian population subgroup (OR = 1.30, 95% CI: 1.19–1.42) and cross-sectional study design subgroup (OR = 1.31, 95% CI: 1.16–1.47). Significant associations of SCH and MetS also existed in all MetS definition criteria subgroups except the Chinese Diabetes Society (CDS) subgroup. SCH was correlated with MetS and was not affected by the subgroup analysis stratified by the proportion of females in the total population, the TSH cutoff value in SCH diagnostic criteria, or the adjustment for confounding factors. SCH was identified to be associated with an increased risk of obesity, hypertension, high triglyceride (TG) levels and low high-density lipoprotein cholesterol (HDL-C) levels. In conclusion, SCH is significantly associated with an increased risk of MetS and four out of five components of MetS.