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고분자 전해질 막의 수화 및 열팽창에 따른 응력분포의 해석에 관한 연구
양정환(Junghwan Yang),손영준(Young-Jun Sohn),박구곤(Gu-Gon Park),김민진(Minjin Kim),박정선(Jungsun Park) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.11
Behavior of membrane has influenced on performance of a polymer electrolyte membrane fuel cell (PEMFC). The stress distribution and deformation of membrane are major factors for performance and mechanical fatigue life of PEMFC. In this paper, numerical modeling of mechanical stresses under the operating hygro-thermal condition of membrane is provided. Contact analysis of gas diffusion layer (GDL) and membrane is performed under various temperature-humidity conditions. Structural model has nonlinear material properties depended on temperature and relative humidity. Several kinds of geometric conditions are applied to the model. The numerical analysis results indicate that the deformation of membrane is strongly related with the assembly conditions of fuel cell.
NIE 프로그램이 청소년의 환경 인식과 실천에 미치는 영향
감예슬(Yeseul Gam),양정환(Junghwan Yang),안경숙(Gyoung Sook Ahn) 한국환경교육학회 2008 環境 敎育 Vol.21 No.2
As the gravity of the issue of the global warming surfaced, environmental protection and energy conservation have become one of the most serious issues that global society faces. At the status quo, there are criticisms for not effectively educating the students although the problem is very severe. In middle school, for instance, only 10% of the school offer environmental education while only 20~30% of the high school offer it. As witnessed by these examples, we can infer that there are not well-structured, effective environmental education for teenagers. Recently. NIE(Newspaper-In-Education) has been used as effective means for some fields of middle and! or high school education. If so, it also could be used for environmental education. The researches, however, on the topic of NIE on environmental education are very rare. In this study, the effect of NIE on environmental education was empirically tested. Our basic assumption is that NIE will cause differences in environmental perception; the cognition and concern. And environment education through NIE will cause the high level of cognition, concern, and practice regarding environment issue. Using simple experimental design and regression analysis, we tested the effect of NIE on cognition, and, concern of environment issue, and then, on the practice of environment-improving action. The cognition level did not show significant difference between the experimental group(which was exposed to NIE) and control group(which was not exposed to NIE). The concern level for environment showed significant difference. Finally, the practice level showed highly significant difference between the experimental and the control group. According to regression analysis, concern and NIE(dummy variable) was turned out to be statistically significant variables for practice of environment-improving action. Therefore, we came up with the conclusion that NIE, which provides the most up-to-date information regarding the environmental status, can serve as the good supplementary mechanism for the effective environment education in the present Korean middle school curriculum system. The statistical result also suggests that each individual school needs to employ and extend NIE method in its environment education curriculum.