http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
고분자 전해질형 연료전지에서 Hot Pressing 조건의 영향
이태희,이승재,조원일,노용우,고영태,최경환 한국화학공학회 1996 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.34 No.1
고분자 전해질형 연료전지에서 고분자막/전극 어셈블리를 hot pressing 조건을 달리하여 제조하고 그 성능을 반응면적 5㎠인 단위전지에서 측정하였다. 전지의 성능은 고분자막과 전극간의 접합이 가능한 온도 범위에서 hot pressing온도가 낮을수록, hat Pressing 압력이 높을수록 향상되었다. 즉, 고분자 전해질형 연료전지의 성능은 고분자 전해질 내의 수분 함량 증가, 고분자막/전극간 접촉저항 감소 및 얇은 고분자막을 사용한 전해질의 이온저항 감소 등으로 향상시킬 수 있었다. For a proton exchange membrane fuel cell, membrane and electrode assemblies were fabricated by different hot pressing conditions and those performances were observed in a unit cell having 5 ㎠ active electrode area. The cell performance increased with lower hot pressing temperature in the range of temperature having intimate contact between membrane and electrodes and with higher hot pressing pressure. Namely, the performance of proton exchange membrane fuel cell could be raised with higher water content in the membrane, with lower contact resistance between membrane and electrodes and with lower ion resistance of the electrolyte using thinner membrane.
손상평가도를 이용한 용접구조물의 균열형 결함에 대한 사용적합성 평가
李精錫,朱章福,張宰溢,金禹植,고영대,權東一 대한금속재료학회 2002 대한금속·재료학회지 Vol.40 No.10
Flaws nucleated during operation of structures such as nuclear power plants, petroleum facilities and gas equipment raise many safety problems, and thus the integrity assessment of crack-like flaws in structures has been very important. Since large-scale structures include weldments with complex micro-structures and inhomogeneous material properties, it is essential to consider both metallurgical and mechanical factors. In this study, a methodology for integrity assessment in welded structures was developed based on API 5L X65 grade natural gas pipeline (an approximately 2400 ㎞ pipeline in Korea). A failure assessment diagram(FAD), which includes all failure modes from linear elastic fracture to plastic collapse, was used for integrity and fitness-for-service(FFS) assessment of the pipeline. Since tensile properties and fracture toughness of base metal, weld metal and heat affected zone(HAZ) are required for the FAD, tensile tests and fracture toughness tests were performed on each region. In particular, the evaluation of representative properties of HAZ make it possible to assess FFS accurately by using the HAZ-based FAD when crack-like flaws exist in HAZ. This HAZ-based FAD is different from current codes, which assess integrity by the material properties of weld metal or base metal even when flaws exist in HAZ.
고영태,박경완 한국부식학회 1994 Corrosion Science and Technology Vol.23 No.1
Various polarization resistance measurement methods are summarized. These include potentiostatic, galvanostatic, potentiodynamic, AC impedance and cyclic polarization methods. Corrosion rate is measured by obtaining polarization resistance value through steady state response of corroding system upon predetermined applied signal All of above mentioned methods are steady state ones where reliable measurement is feasible only when steady state is reached. Problems associated with increased measuring time as a result of decreasing corrosion rate and/or increasing electrolyte resistance is analyzed for each method. Need for investigation on new method based on transient behavior, reducing measurement time thereafter, is proposed as a conclusion.
운전 조건에 따른 고분자 전해질형 연료전지의 전지 성능
목영일,노용우,조원일,고영태,이진홍 한국화학공학회 1995 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.33 No.2
고분자 전해질형 연료전지에서 전극/고분자막의 접합체 제조기법, 전극/고분자막 재료에 따른 전지 성능의 영향 및 온도, 압력, 반응 가스의 가습 조건 등과 같은 운전 조건에 따른 전지 성능의 영향에 관하여 고찰하였다. 고분자 전해질형 연료전지의 성능은 접합체 구성 재료 중 고분자 막의 특성에 크게 의존하며 가습 조건은 산소쪽은 단위전지의 온도보다 약 5℃정도, 수소 쪽은 10℃ 정도 높게 유지하는 것이 최적의 조건임을 알 수 있었다. 또한 전지 작동 온도에 따른 전지 성능은 70℃ 이하에서는 온도 증가에 따라 반응 활성도 증가하나. 운전 압력이 1기압일 경우 70℃ 이상에서는 전지 온도 상승에 의한 활성의 증가를 볼 수 없었다. 이것은 전지온도를 상승시킬 경우 물의 포화 증기압도 올라가 이에 따른 반응가스의 농도가 낮아지기 때문으로 생각된다. 작동 압력이 2기압 이상인 경우에는, 물의 포화 증기압이 전체 반응 가스의 농도에 큰 영향을 미치지 않음을 알 수 있었으며 결과적으로 온도 상승에 따른 활성의 증가가 90℃까지 계속되었다. 일정한 온도에서 전지의 성능은 작동 압력이 증가할수록 이에 비례하여 증가함을 알 수 있었다. The performance of proton exchange membrane fuel cell was investigated to optimize the fabrication method of membrane/electrode assembly, and to find appropriate operating conditions such as pressure, temperature and inlet gas humidification. It is the membrane electrolyte that has decisive effect on the cell performance. The optimum condition for humidification could be found by varying the inlet gas temperatures. Gas temperature 5℃ for oxygen and l0℃ for hydrogen higher than that of cell temperature was found to the optimum humidification condition irrespective of the cell temperature. Increase in temperature and/or pressure generally resulted in enhanced cell performance. The cell performance operated at 1 atm, however, exhibited an interesting temperature dependence. Enhanced performance with increasing temperature was observed up to 70℃, whereas cell temperature showed no appreciable effect on the cell performance above 70℃. This observation might be attributed to the increased vapor pressure, with increasing temperature, which dilutes inlet gas composition. Cells operated at higher pressure did not show this behavior where the effect of increased vapor pressure becomes relatively insignificant.