著者

城戸 竜太 桑野 亮一 日野 実 村山 敬祐 黒坂 成吾 小田 幸典 堀川 敬太郎 金谷 輝人

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.84, no.3, pp.74-79, 2020-03-01 (Released:2020-02-25)

参考文献数

11

被引用文献数

1 1

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In this study, the effect of anodization and electroless Ni-P plating on the fatigue strength of commercial A5052-H14 and A2017-T4 aluminum alloys was investigated. The coated aluminum alloys were tested using a rotary bending fatigue testing machine. Anodization led to a slight increase in the fatigue strength of the A2017-T4 alloy of approximately 10% because of the suppression of the generation of fatigue crack, and anodization with a 5-µm thickness for A5052-H14 also led to a slight increase in the fatigue strength. However, anodization with a 20-µm thickness for A5052-H14 led to reduced fatigue strength because of the pits that formed in the film. In addition, electroless Ni-P plating drastically improved the fatigue strength of the A5052-H14 alloy by suppressing the generation of fatigue crack.It also improved the fatigue strength of the A2017-T4 alloy in the high-stress region. However, the fatigue strength in the low-stress region was the same as that of the non-coated specimens.This fatigue strength should have originated from the hydrogen embrittlement by the hydrogen introduced into the specimen during the plating.

著者

藤原 豊 堀川 敬 本多 敏朗

出版者

一般社団法人 日本糖尿病学会

雑誌

糖尿病 (ISSN:0021437X)

巻号頁・発行日

vol.55, no.4, pp.249-257, 2012 (Released:2012-05-28)

参考文献数

22

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日本人2型糖尿病患者を対象に膵β細胞機能の12ヶ月間の変化と影響因子を検討した.著しい高血糖からの離脱例,高度肥満例,進行した肝障害,腎障害,インクレチン使用例,インスリンと経口血糖降下薬併用例を除外し,血糖コントロールが3ヶ月以上良好で安定している症例205名を対象とした.膵β細胞機能はグルカゴン負荷試験のCペプチドの6分間の反応量(ΔCPR)で評価した.検討する臨床指標は,年齢,性別,糖尿病罹病期間,糖尿病網膜症,高血圧,尿アルブミン,HbA1c,血清脂質を用いた.観察開始時(ベースライン)での横断的検討では,糖尿病罹病期間はΔCPRと有意(r=0.357, p<0.001)な負の相関を示した.ステップワイズ法による重回帰分析の結果,臨床指標の中で糖尿病罹病期間はΔCPRを予測する主な独立変数(F=16.951)であった.全対象例の12ヶ月間の縦断的検討で,ΔCPRは有意(p<0.001)に低下した.これらを治療法別に検討すると,非薬物療法群(39名)と経口血糖降下薬群(134名)のΔCPRはそれぞれ有意(p<0.05, p<0.001)に低下したが,インスリン治療群(32名)のΔCPRは有意な変化は認めなかった.経口血糖降下薬群での投薬内容に関するサブ解析で,ΔCPRの低下にインスリン分泌促進系経口血糖降下薬,特にスルホニル尿素薬の関与が強く示唆された.日本人2型糖尿病における膵β細胞のインスリン分泌能の経年変化には,高血糖曝露による自然史的影響ばかりでなく,種々の治療方法の影響が関与していることが示唆された.

著者

沖野 友洋 永田 恵輔 堀川 敬太郎 小林 秀敏

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

pp.19-00249, (Released:2019-12-26)

参考文献数

13

被引用文献数

2

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The crash safety structure of the railway vehicles is effective as one of the safety measures against the train crews and the passengers in the event of a collision accident. The standards for crashworthiness of railway vehicles are defined in Europe and the U.S., while there are no standards for crash safety in Japan. Therefore, it is important to establish the evaluation method for crashworthiness of railway vehicles considering the actual situation of collision accidents in Japan. The authors carried out finite element analyses of a level crossing accident under various conditions (collision speed, mass of the obstacle and relative position between the train and the obstacle) based on the statistical analysis of serious level-crossing accidents in the past in Japan, and calculated the deceleration time histories in the passenger area under each condition. We evaluated these deceleration waveforms according to European and the U.S. standards for crashworthiness, and we also performed finite element analyses of dummy’s behavior and injury values using these deceleration waveforms as input. We verified the correlation between the evaluation results in terms of the deceleration according to these standards and dummy’s injury values obtained by finite element analyses. As a result, the evaluation according to the velocity at which a passenger contacts the seat back ahead of him (the U.S. standards) was the most effective. Moreover, the integrated values of the deceleration of the passenger area during an integration time t360 had the highest correlation with the dummy’s injury values.

著者

沖野 友洋 永田 恵輔 佐藤 裕之 堀川 敬太郎 小林 秀敏

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.85, no.869, pp.18-00270, 2019 (Released:2019-01-25)

参考文献数

11

被引用文献数

2 4

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The crash safety structure of the railway vehicles is effective as one of the safety measures against the train crews and the passengers in the event of a collision accident. However there is no standard for crash safety in Japan. In order to discuss guidelines for the crash safety design of the vehicle structure, it is important to grasp the actual situation of collision accidents in Japan. Therefore, firstly the authors performed the statistical analysis of serious level-crossing accidents for the past 30 years. Secondly, we carried out finite element analyses of a level crossing accident with a dump-truck under various conditions (collision position, collision angle, collision speed and mass of the load on the dump-truck) based on the result of the statistical analysis. We also evaluated their results in terms of the contact force, the deformation energy of the rail vehicle, the deformation amount of the cabin, the mean deceleration of passenger’s area (conformable to European standard), the maximum deceleration of the passenger’s area and the secondary impact velocity of the passenger (American standard). The degree of correlation among these results was discussed. The analyses showed that the horizontal collision position of the dump-truck and the collision speed had a comparatively large effect on the safety of passengers, and further that the mass of the load on the dump-truck also affected it when the secondary impact velocity was used as an evaluation index.

著者

小林 秀敏 富永 直路 堀川 敬太郎 渡辺 圭子

出版者

一般社団法人日本機械学会

雑誌

バイオエンジニアリング講演会講演論文集

巻号頁・発行日

vol.2012, no.24, pp."8G33-1"-"8G33-2", 2012-01-06