Publications

Achievement of high fusion triple product in the JT-60U high _pH mode

Improvement of an enhanced confinement state in a high poloidal beta (βp) regime without sawtooth activity has been achieved in JT-60U. A confinement mode has been demonstrated where both the edge and the core confinement are improved. The attainable βp was also extended to higher values in this improved mode, because of its broader pressure profile. As a result of the improvement in confinement and in attainable βp, the highest value of the fusion triple product has been extended by a factor of 2.5 over that achieved in the 1992 experiments; it has reached (1.1 ± 0.3) × 1021 m-3.s.keV with a central ion temperature of about 37 keV. The D-D neutron emission rate has also been doubled in these experiments and has reached (5.6 ± 0.6) × 1016 s-1

Neutral pressures in JT-60 divertor discharges

Lactonamycin, a New Antimicrobial Antibiotic Produced by Streptomyces rishiriensis MJ773-88K4. II. Structure Determination.

Deuterium retention in plasma spray tungsten coatings exposed to low-energy, high flux D plasma

Newly developed low power impregnated cathode for CRTs

In the development of low power impregnated cathode, to decrease heater power the Taguchi method has been used. The newly developed low power impregnated cathode can he applied to a new electron gun-we call this technology "L-SAGIC"-enabling the CRT's to achieve good performance and high resolution and brightness.

Analytical Study of Torsional Moment Induced by Shifting of Shear Center of RC Cross Sections

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Effect of corrosion‐induced crack and corroded rebar shape on bond behavior

This paper aims to investigate the individual effect of corrosion‐induced crack, corroded rebar shape, and rust around rebar on the bond properties of reinforced concrete (RC) members. First, test specimens were corroded by accelerated electric corrosion method with varying corrosion degree ranging from 0 to 25%. Test specimens were divided into different groups. For the normal corrosion group, bond test was conducted directly after the corrosion test to investigate the combined effects including corrosion‐induced crack, corroded rebar shape, and rust on bond deterioration. In another group, after corroded rebar was taken out from test specimen, rust was removed before casted into new concrete to evaluate single effect of corroded rebar shape. Similarly, corroded rebar with rust was casted into new concrete to evaluate the effect of the formation of rust on bond degradation. Experimental results quantitatively illustrate the influential factors including corrosion degree, corrosion crack width and geometry of corroded rebar. As the important finding, corrosion crack in concrete is concluded to be a more dominant factor than the corroded rebar shape and rust accumulation in bond deterioration mechanism. Moreover, rust accumulation contributes to the improvement of bond deterioration induced by corroded rebar shape.

Evaluation of crack opening performance of a repair material with strain hardening behavior

H-mode investigations in DIII-D

DIII-D is a large tokamak (major radius R = 1.67 m, minor radius a = 0.67 m), capable of producing vertically elongated limiter and divertor plasmas with high plasma current at modest toroidal field (B/sub T/ = 2.2 T on axis). To date, maximum plasma currents achieved are 3.0 MA in limiter plasmas (elongation in excess of 2.0), 2.0 MA in divertor plasmas (elongation 1.9). The DIII-D divertor is a reactor-compatible open divertor design, with no separate divertor chamber and no coils in vacuum. The divertor plates are two toroidal bands of carbon tiles on the bottom of the vacuum vessel. Deuterium plasmas are heated by hydrogen neutral beams (75 keV, coinjection only) and electron cyclotron heating /1/. Power levels to date are 6 MW (beam) and 1.0 MW (ECH). H-mode discharges, H-mode thresholds, and Edge Localized Modes have been investigated for this system.

Evaluation of the effect of vertical crack growth process and compressive strength on concrete members with a cylindrical cross section

[Treatment of the mother fluid containing mercury in the acetaldehyde plant in a Minamata factory].

Tritium Release Behavior from JT-60U Vacuum Vessel during Air Exposure Phase and Wall Conditioning Phase

The behavior of tritium release from the vacuum vessel of JT-60U during air exposure phase at controlled water vapor concentration and gas purging in the wall conditioning phase has been investigated. For the air exposure with varying water vapor concentrations of 40ppm, 300ppm, 680ppm and 3400ppm, tritium concentration in the vacuum vessel of JT-60U was measured. At each water vapor concentration, tritium concentration initially increased with time and then became steady finally. The steady tritium concentration increased with water vapor concentration. The total amount of tritium released from the vacuum vessel was 13MBq for 3400ppm. This amount is almost the same as that removed by 5 hours’ H2-GDC, which has been the most effective method for tritium removal from JT-60U. This suggests that tritium in the vacuum vessel of JT-60U can be easily removed by water vapor. Tritium released into exhaust gas during gas purging was also measured for varying gases (H2, He and Ar), at different pressures and temperatures of the vacuum vessel. Tritium concentration of the exhaust gas was about 0.1Bq/cm3 at room temperature and was independent of gas species within the pressure from 0.05 to 0.3 Pa. This result indicates that isotope exchange of tritium with hydrogen molecules was not so active under these purge conditions.

Deuterium diffusion in a chemical densified coating observed by NRA

Real-time damage estimations of 2016 Kumamoto earthquakes extrapolated by the Japan Real-time Information System for earthquake (J-RISQ)

Discrete modeling of concrete materials and structures

STUDY ON DETECTION OF INTERNAL CRACK AND REBAR CORROSION AREA BY ELECTROMAGNETIC WAVE RADAR DATA USING SELF-ORGANIZING MAP

電磁波レーダを用いたコンクリート構造物内部のひび割れ領域および鉄筋腐食領域の可視化に関する実験的研究を行った．まず，鉄筋かぶり（30，60mm）と腐食率を実験変数として電食実験により局所的な領域に腐食を生じさせた供試体を作製し，内部のひび割れ幅・分布情報および鉄筋の腐食率分布を評価した．この供試体を対象として電磁波レーダより得られる電磁波波形の健全供試体との違いを考慮した指標を自己組織化マップ（SOM）に適用し，内部ひび割れ・腐食領域の可視化を試みた．その結果，1段階のSOM適用により，鉄筋の腐食領域を検出できることを確認した．さらに，2段階のSOM適用による評価を試みたところ，内部ひび割れの存在を定量的かつ明瞭に検出できることを確認し，その適用範囲は内部ひび割れ幅0.1～0.4mm，腐食率4%以上であった．

Estimation of anisotropy of expansion from crack orientation in concrete damaged by alkali–silica reaction under constraint conditions

A case of reiterative speech following encephalitis.

脳炎後，推定７年間にわたる持続性の反復性発話を呈した１例を経験した。症例は発症時22歳，右利きの男性。約７年後の評価時には，日に数回意識減損発作があり，発動性低下，病識低下，脱抑制傾向などの精神症状を認めた。MRI検査では右前頭・側頭・頭頂葉および左側頭葉に萎縮がみられ，また右優位の側脳室の拡大を認めた。神経心理学的には失語および広義の聴覚失認 (言語音，環境音，メロディの聴覚的認知障害) ，さらに自己の発話の著明な反復を認めた。この反復の単位は１音節を主とし，次に単語，複数音節の順に多かった。反復の位置は語中・語尾に高頻度で，語頭はこれに比し少ない傾向があった。本例の反復性発話の臨床症候は語間代にもっとも当てはまると考えられ，語間代は Alzheimer 病に限られるものではないことが示された。