技術開発プロジェクトでは, CAE(コンピュータ援用エンジニアリング)シミュレーションのツールとして有限要素法(FEM)を用いることが多い. FEMは極めて有効な解析シミュレーションツールであるが, その利用の困難さのため専門家に解析を依存することが多い. 本研究では, 技術開発プロジェクトが容易に利用可能なネット対応型FEMコンサルティングシステム(以下FEM・CS)について検討した. さらに, 本研究で開発したFEM・CSを用いてシミュレーション解析した技術開発事例について紹介する.

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太陽光発電システムの直流電気事故対策—Ⅰ (バイパス回路の点検)　池田　一昭

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The stress corrosion properties of GFRP, made of glass cloth or glass chopped strand mat and unsaturated polyester resins, have been evaluated under acidic conditions. Four types of unsaturated polyester resins were used as the matrix. Each matrix resin has a different fracture toughness level.
The retention strength of the cloth-GFRP and mat-GFRP under acidic conditions were 20-40% and 40-80% of the original strength in air, respectively, at a very slow tensile rate. The retention strength vs. fracture toughness curve showed the existence of an optimum value in matrix toughness for the high performance of stress corrosion.
The fatigue induced cracks did not give any degradation in the tensile strength in air, but decreased the tensile strength of GFRP significantly under acidic conditions. The results show that the fracture toughness of matrix resin is a critical parameter in determining the rate of fatigue crack propagation.

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By the Feed-in Tariff in Japan enforced in July，2012，quantity of introduction to photovoltaic system （PV system） for residence and business suddenly increases. Though each panel maker expands guarantee about output lowering and trouble of the PV system, the method to judge the degree and cause of output lowering is not established. The authors study on output lowering diagnostic method using the % electric energy. At first in this paper, we examined an output lowering judgment using the % electric energy. It became clear that the judgment of the output lowering using the % electric energy was possible，even if it was the day when the sunlight strength was unstable. In addition，it became clear that the evaluation of % electric energy was possible by using different weather data（ambient temperature, wind speed and global solar irradiance)when we could not measure weather data(total solar irradiance and module temperature)to be necessary for the evaluation. We were able to confirm that there was strong correlation between a change of the % electric energy and change of the evaluation. We were able to confirm that there was strong correlation between a change of the % electric energy and change of the output. Finally the authors propose the value that attracted standard deviation from the mean of the % electric energy as a decision method of the criteria of the output lowering using the % electric energy.

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The photovoltaic power generation system (PV system) has been expected as a clean energy source. However, it is supposed that the system reliability is not so high. In this study, the operational performance on large-scale photovoltaic power generation system was evaluated by using 12 systems. The standard rated output of each system was 4kW. As the results of the evaluation analysis, the rate of output deviation of System4 decreased 25% or less, in comparison with estimated output and the operation efficiency was unstable. It was obtained that the decrease of operation efficiency was caused by String3. From the results of inspections of the module, the solar radiation and the power conditioner, there was difference in conversion ratio between a DC-DC converter of a normal string and that of String3. The conversion ratio affected on the output of the string. It was able to find malfunction. Moreover, the regression analysis was investigated by using the output data of the PV system and irradiance. Performance of the PV system was evaluated using the regression coefficient. Stability of the PV system was also investigated using the method of this study.

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The effect of the cooling process on superconductivity has been studied for the samples with nominal compositions of Bi_1.6Pb_0.5Sr_2.0Ca_2.0Cu_3.0O_z sintered at 1123K for 80h in air. The results are summarized as follows:
(1) Samples which have the cooling rates of the range from 1 to 100K/minn have shown good superconductivity, the critical temperature > 100K and the critical current density > 80A/cm².
(2) From TG measurements, the two oxidation peaks in cooling process have been observed, where these high and low temperature peaks seem to be related to the reactions of 2223 and 2212 phases, respectively.
(3) The critical current density has increased from 80 to 165A/cm² by the cooling process with holding at 1093K for a few hours.

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e ラーニングシステムは多くの高等教育機関において導入・利用されている．これによって，時間や場所が制限 されることなく，学習できる環境が提供されている．e ラーニングが授業に活用される機会が増えたことで，シス テムへの依存度が高まり，システム障害が授業の運用に大きな影響を及ぼす可能性がある．このような中，近年， クラウドコンピューティングを利用した高可用性の実現が注目されている．本研究では，クラウドコンピューティ ング基盤ソフトウェアKumoi を用い，障害時の動的な仮想リソース変更およびそれに応じた自動アプリケーション 制御により，e ラーニングシステムの高可用性を実現する方法および展望について述べる．

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In this paper, based on the data of field exposure test, which was initiated by Japan Electrical Safety & Environment Technology Laboratories (JET), we investigate the degradation characteristics of crystalline silicon PV modules by using its equivalent circuit model for the purpose of the lifetime extension in the development of PV modules. Specifically, we observe the degradation of bus bar electrode and solar cell by capturing electro luminescence images and infrared images of the surface of PV modules when forward voltage is applied. Although this observation enables us to determine which part of the PV module deteriorates, it is impossible to quantitatively evaluate how much each deteriorated component has an influence on power degradation. Accordingly, using the equivalent circuit model of the PV module, we calculate the equivalent circuit parameters from the measured I-V characteristics of the PV modules in the field exposure test by the least squares method. We adopt the photocurrent, series resistance, shunt resistance and diode factor as unknown parameters in the equivalent circuit model. Based on the change of the circuit parameters, we evaluate the influence of the deterioration of each component on decline of output power quantitatively.

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