Stress corrosion cracking (SCC) was investigated by spectral analysis of corrosion potential signals. Caustic cracking of carbon steel (S10C) and SCC of stainless steel (SUS304) in various chloride solutions were studied. The marked change of the power spectral density (PSD) in the frequency domain was observed in the vicinity of 5mHz for caustic cracking of carbon steel and in the frequency range from 10 to 100mHz for SCC of stainless steel. It was also observed that the corrosion potential signal in 20%NaCl+1%Na₂Cr₂O₇ solution was bigger than in 42%MgCl₂ solution or 60%CaCl₂ solution for SCC of Stainless steel. By comparing PSD with the changes of elongation and corrosion potential, the following conclusion was obtained: the increase of PSD might be related to the breakdown of passive film and the generation of cracks for caustic cracking of cabon steel, while its increase might be attributed to the localized change in the passive film for SCC of stainless steel.

抄録全体を表示

本研究の目的は、都心と森林に囲まれた家との間の暑熱環境の違いを明らかにすることである。ヒ ートアイランドが指摘されている名古屋市のクールアイランド効果を把握する目的で、雑木林の気候緩和 効果を検討した。都市化による気温上昇の長期的な傾向があり毎日の最低気温の上昇率は特に高く、気温 の上昇率は都市化率が高い場所ほど大きかった。

抄録全体を表示

Corrosion potential fluctuation was analyzed to investigate the stress corrosion cracking of SUS304 stainless steel immersed in 42 mass% MgCl₂ solution. A potential difference between the specimen and the Ag/AgCl reference electrode was measured with a precise digital voltmeter at a sampling frequency of 2.56Hz. Elongation of the specimen was measured with a differential transformer at 10s interval, for the computation of elongation rate.
From an electrochemical point of view, the measured corrosion potential was divided into a component of the signal shifted to a more noble potential (Signal of Repassivation) and the one shifted to a less noble potential (Signal of Film Breakdown). These two types of signals were extracted from the sampling data by use of the differential coefficient at each data point. To avoid an errorr in the FFT calculation, the extracted signal was extended symmetrically. Then, a power spectra density (PSD) was calculated by FFT algorithm for each type of signal.
The difference in PSD level between two types of signal showed a good correlation with the elongation rate of the specimen. During the time when the elongation rate increased, the value of PSD for the signal of film breakdown became bigger than that of repassivation in the frequency range 10-100 mHz. Conversely, the PSD level for signal of repassivation exceeded that of film breakdown, when the elongation rate decreased or kept a constant value, in the same frequency range.

抄録全体を表示

国土の約 65% を占める中山間地域の都市における，気候特性の観測事例は少なく，地元資源を活かしたまちづくりを行っていく上には，都市気候を知ることは重要と考えられる．本研究は，岐阜県郡上市八幡町においてヒートアイランドの形成，河川・山地の存在が市街地の都市気候に及ぼす影響を明らかにすることを目的とするものである．2007 年 8 月 23 日に気候観測を実施した．観測点 27 点を設定して，8:30，13:00，16:30，21:00 の 4 つの時間帯で移動観測を行った．その結果，日中にはヒートアイランド強度 5.0℃のヒートアイランドの形成を観測した．河川沿いをのぞくと，可照時間と気温との相関が認められた．山地からの渓谷がある場所では，冷気のにじみだしが低温域を形成していることが見いだされた．河川沿いでは，一日を通して水体の熱容量および上流からの冷気の影響により低温域が形成されていた．

抄録全体を表示

前報で，名古屋市付近の団地内の微気候においてスポットが形成され，それらが発現・消失を繰り返すことを報告した．その結果に注目し，本研究では微気候の形成に及ぼす影響要因に関してさらなる調査を実施した．観測結果から，局地風の性状及び風温によって局地の気温が影響を受けることを確かめた．また，風温は局地風の流れに沿った地物の表面温度の影響を受け，地物と風の間の熱交換が風温を変化させることを確かめた．さらに，地物などの表面温度の影響が大きくなるのは，日射受熱により地面や地物の表面温度が上昇した午後に顕著になる傾向も確かめた．

抄録全体を表示

Electrochemical noise generated from corrosion potential of Type 304 stainless steel in MgCl₂ solution has been studied by using a FFT analysis. White noise was observed in a frequency range below 0.1Hz and hence PSD at 0.05Hz was used as a measure for a noise power of the system. PSD at 0.05Hz was found to change as a function of the concentration of MgCl₂, temperature and immersion time. The slope of the log(PSD) vs. log(t) line was correlated with the kinetics of the film formation, by assuming that corrosion velocity is proportional to PSD.

抄録全体を表示

Corrosion potential fluctuation of SUS304 stainless steel during stress corrosion cracking (SCC) was observed in a 35 mass% MgCl₂ (353K) solution. The potential fluctuation was measured against an Ag/AgCl reference electrode with a digital voltmeter at a sample frequency of 2.56Hz. During the propagation stage of SCC, a trapezoidal potential fluctuation was observed, whose amplitude and frequency were about 1mV and one or a few times each 3.6ks, respectively. When the experiment was carried out without loading, the trapezoidal potential fluctuation was not detected. The effect of solution temperature on the corrosion potential fluctuation was also examined. An amplitude and an occurrence frequency of the trapezoidal potential fluctuation decreased with a decrease in temperature. The critical temperature for the SCC in the chloride solution environment had been reported to be 323K. The trapezoidal potential fluctuation disappeared at the temperature lower than 333K. Therefore, it was estimated that the trapezoidal potential fluctuation was only generated during the propagation stage of SCC.

抄録全体を表示

超低高度衛星技術試験機「つばめ」（以降，SLATS : Super Low Altitude Test Satellite）の姿勢制御用搭載機器である国産新型ホイール・タイプS は，10Nms以下クラスの国産リアクションホイール（RW）として開発された．本ホイールは，それまで輸入品に頼っていた小型RWに関して，高信頼性，高品質な国産品に対するユーザからのニーズにこたえるために開発を行ったものであり，SLATSに搭載され軌道上実証することとなった．本ホイールの地上での開発は順調に進み，2017年12月のSLATS打ち上げ後も約2年弱の運用期間にわたり軌道上で順調に動作し続け，機器特性や健全性等に関する貴重な結果をもたらした．本解説記事では，国産新型ホイール・タイプSの開発結果と軌道上での実証結果について紹介する．

抄録全体を表示

Transient behaviors of corrosion current of Type 316 stainless steels during a slow strain rate test (SSRT) in high-purity oxygenated water at 288°C were investigated and their correlation with stress corrosion cracking (SCC) was discussed. Corrosion current at corrosion potential between a specimen under slow-rate straining and a counter electrode which was made of the identical alloy to the specimen was continuously monitored using a zero resistance ammeter. Spike-like current pulses were observed after yielding. The current pulses had short rise-time, typically a few seconds, and slow decay behavior, 100-1000 seconds; This characteristic was considered to correspond to the slip dissolution processes. Although the current pulses were observed both on the solution treated material and on the sensitized one, characteristics of the current pulses reflected well the difference in SCC susceptibility of the samples. Current pulses from the sensitized material had higher peak and slower decay rate than those from the solution treated one. Capability of the current noise monitoring for detecting SCC initiation in austenitic stainless steels in high-temperature high-pressure water was demonstrated and it was suggested that the current noise can provide real-time evaluation of SCC behavior.

抄録全体を表示

Impulsive vibration during rocket launch has the risk of causing indentations inside the bearings of reaction wheel mounted on a satellite. The indentations induce the vibration disturbance during the bearing rotation, which is harmful to precision equipment. In order to investigate the mechanism of the indentation formation, we carried out the experiments and finite element simulation for simplified reaction wheel. Based on the results of simulation, we estimated the depth of plastic deformation and wear using Palmgren’s formula and PV value, respectively. The indentation depth of simulation shows good agreements with that of experiment. The results also show that the wear between balls and rings is dominant factor of indentation formation, as compared with the plastic deformation. The amount of wear is greatly affected by the location of ball. In the location where the contact direction between ring and ball is parallel to the vibration direction, contact pressure contributes the wear as compared with slip velocity. Inversely, in the location where the contact direction is perpendicular to the vibration direction, the slip velocity contributes the wear and induces the larger wear region.

抄録全体を表示

We developed the Environmental Monitoring System that was able to combine a collection of the measurement data of the broad zone and immediacy, whose draw on the cell-phone network or human power conventionally. This system was installed on the site of EXPO2005 in Aichi as Environmental Monitoring System (Expo Amedas) and its stability and immediacy were confirmed.

抄録全体を表示

"　超音波を用いた治療方法として、骨折の治りを早める低出力パルス超音波療法（LIPUS）があり、超音波照射が骨芽細胞の遺伝子に影響を与えていることが確認されている。このように、超音波照射によって細胞の活性を向上させることができれば、細胞分裂を活性化させられるため、近年着目されているCAR-T細胞療法などの体外培養を必要とする治療法への応用が考えられる。一方我々の研究室では、超音波照射の細胞への影響を微小気泡存在下で検討していたが、超音波照射条件に対する影響の調査は不十分であった。　そこで本研究では、マウス由来のT細胞であるCD8-OVA1.3細胞を対象に、超音波照射条件によって生じる傷害の程度を解析することを目的とする。細胞と液体培地の懸濁液を注入したウェルプレートを水温37℃とした脱気水の水面に設置し、水槽底部に設置したトランスデューサによって超音波照射を行った。照射条件は周波数2,3,5 MHzで音圧、照射時間、Duty比をパラメータとした。照射後に懸濁液に生細胞数を反映する蛍光試薬を注入し、懸濁液の吸光度から細胞生存率を算出した。　一連の実験の結果、音圧400 kPa-ppの連続波（Duty比100％）の場合、周波数3 MHzで生存率が最も低くなった。一方、同条件からDuty比のみを20 %に下げると生存率は100 %に近づくため、傷害性には様々な要因が起因していると考えられる。"

抄録全体を表示

For utilization of wood eliminated by thin-out of the Japanese cedar forest, the following experiment was carried out to aim to apply compressive formed lumbers produced by convertiny of compressive forming to furniture and woodworking goods.Determination on change per time process. The adhesion test of painting membrane of compressive formed lumbers, The determination declared that measure becomes stable in around three months after formation. As a result of the stuck test of painting membrane, it was found out that compressive formed lumbers suit oil finish painting. On the basis of this study on compressive formed lumbers, they are applied to products.

抄録全体を表示

内耳に発現する膜タンパク質であるペンドリンの変異は，重度の感音難聴を引き起こす．我々はこれまでにこの変異ペンドリンにサリチル酸を投与することでその局在異常と機能が回復することを報告している．また，サリチル酸誘導体を投与することでも局在異常を回復できることを見出してきた．しかし，機能回復効果についてはまだ明らかになっていない．そこで本研究では，固相法による遺伝子導入を用いた，化合物評価系の構築を目的とした． 従来法と新たに構築した固相法によってHEK293細胞に緑色蛍光タンパク質（GFP）発現ベクターを導入し，24時間後に蛍光顕微鏡を用いて画像を取得した．画像解析により総細胞数とGFP発現細胞数を求め，トランスフェクション効率を評価した．その結果，固相法は従来法と同程度のトランスフェクション効率約15%を維持しつつ，細胞生存率を従来法から約30%向上できることが確認され，機能回復化合物の評価系として有効であることが示唆された．

抄録全体を表示

症例は 44 歳，女性。主訴は 5 年前からの紅色皮疹（顔面，前胸部，両上肢），1 カ月前からの上腕と下肢の筋肉痛であった。末梢血で筋原性酵素の上昇（LDH 260 IU/l（119～229），アルドラーゼ 7.6 IU/l （2.7～5.9））とミオグロビンの上昇（67.4 ng/ml（25～58））を認め，抗核抗体 80 倍，抗 Jo-1 抗体陰性，抗 Mi-2 抗体陽性（Line blot 法）であった。徒手筋力テスト（MMT）では三角筋 4/4，上腕二頭筋 4/4，大臀筋 4/4 と近位筋の筋力低下を認めた。左上腕二頭筋の筋生検では変性が強く細胞成分に乏しかったものの，臨床所見と合わせて皮膚筋炎と診断した。プレドニゾロン 60 mg/日より内服開始し，皮疹・筋症状ともに速やかに軽快し，検査値も正常化した。ステロイドが奏効した症例であり，悪性腫瘍および間質性肺炎の合併はなく予後良好群に分類したが，慎重にプレドニゾロン漸減中である。

抄録全体を表示