• 한국수소및신에너지학회논문집
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• 제24권6호
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• pp.480-486
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• 2013

In this study, tubular SOFC unit cell with advanced anode current collector was fabricated to improve the cell performance. First, we prepared two types of single cells having the same manufacture processes such as the same electrolyte, electrode coating condition and sintering processes. And then to compare the developed single cell performance with conventional cells, we changed the anode current collecting methods. From the impedance analysis and I-V curve analysis, the cell performance of advanced cell is much higher than that of conventional cell.

• Structural Engineering and Mechanics
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• 제77권3호
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• pp.417-439
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• 2021

The geometric nonlinearity has been successfully integrated with the design of steel structural system. Thus, the tubular lattice girder, one application of steel structural systems have already been optimized to obtain an economic design following the completion of computationally expensive design procedure. In order to decrease its computing cost, this study proposes to employ five multi-objective metaheuristics for the design optimization of geometrically nonlinear tubular lattice girder. Then, the employed multi-objective optimization algorithms (MOAs), NSGAII, PESAII, SPEAII, AbYSS and MoCell are evaluated considering their computing performances. For an unbiased evaluation of their computing performance, a tubular lattice girder with varying size-shape-topology and a benchmark truss design with 17 members are not only optimized considering the geometrically nonlinear behavior, but three benchmark mathematical functions along with the four benchmark linear design problems are also included for the comparison purpose. The proposed experimental study is carried out by use of an intelligent optimization tool named JMetal v5.10. According to the quantitative results of employed quality indicators with respect to a statistical analysis test, MoCell is resulted with an achievement of showing better computing performance compared to other four MOAs. Consequently, MoCell is suggested as an optimization tool for the design of geometrically nonlinear tubular lattice girder than the other employed MOAs.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 추계학술대회 논문집
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• pp.601-602
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• 2010

• 한국세라믹학회지
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• 제42권12호
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• pp.777-786
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• 2005

The Solid Oxide Fuel Cell (SOFC) is an electrochemical device to convert chemical energy of a fuel into electricity at temperatures from about 600 to $1000^{\circ}C$. The SOFC offers certain advantages over lower temperature fuel cells, notably its ability to use CO as a fuel rather than being poisoned by it, and high grade exhaust heat for combined heat and power, or combined cycle gas turbine applications. This paper reviews the operating principle, materials for different cell and stack components, cell designs, and applications of SOFCs. Among all designs of Solid Oxide Fuel Cells (SOFCs), the most progress has been achieved with the tubular design. However, the electrical resistance of tubular SOFCs is high, and specific power output $(W/cm^2)$ and volumetric power density $(W/cm^3)$ low. Planar SOFCs, in contrast, are capable of achieving very high power densities.

• Journal of Acupuncture Research
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• 제18권1호
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• pp.88-99
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• 2001

Objectives : This study was performed to determine if Orostachys japonicus A. Berger aquacupuncture (OjB) provides the protective effect against the loss of celi viability and DNA damage induced by oxidant in renal proximal tubular cells. Methods : The cell viability was evaluated by a MTT reduction assay and DNA damage was estimated by measuring double stranded DNA breaks in opossum kidney (OK) cells, an established proximal tubular cell line. Lipid peroxidation was determined by measuring malondialdehyde (MDA), a product of lipid peroxidation. Results : $H_2O_2$ increased the loss of cell viability in a time-dependent manner, which were prevented by 0.1% OjB. The protective effect of OjB was dose-dependent over concentration range of 0.05-0.5%. $H_2O_2$ caused ATP depletion and DNA damage, which were prevented by OjB and the hydrogen peroxide scavenger catalase. The loss of cell viability by $H_2O_2$ was not affected by the antioxidant DPPD, but lipid peroxidation by the oxidant was completely inhibited by DPPD. Conclusions : These data suggest that $H_2O_2$-induced death results from a lipid peroxidation-independent mechanism and the protective effect of OjB is not associated with its antioxidant activity.

• Transactions on Electrical and Electronic Materials
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• 제12권1호
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• pp.1-6
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• 2011

This paper summarized concept, manufacture and results of the micro-tubular solid oxide fuel cells (SOFCs). The cells were fabricated by co-sintering of extruded micro-tubular anode support and electrolyte coating layer, and then additional cathode coating. The cells showed quick voltage rising within 1 minute, and the electrochemical performances were closely related to the balance of fuel utilization and performance loss. And a thermal-fluid simulation model was also reported in combination with the electrochemical evaluation results on the GDC-based micro-tubular SOFCs.

• 청정기술
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• 제16권4호
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• pp.297-303
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• 2010

본 연구에서는 유체유동해석프로그램인 Fluent를 이용하여 연료극 지지채식 관형 고체산화물 연료전지(SOFC)에서의 연결재 구조에 따른 성능 변화를 고찰하였다. 실험적 사실과 부합되는 이론적 결과를 확보하기 위해서는 전기적으로 전극과 하나로 되어있는 연결재의 구조가 전지 성능에 어떠한 영향을 미치는지 살피는 것이 중요하다. 두께가 작은 연결재가 단전지 성능을 우수하게 하는 것으로 보아 옴(ohmic) 저항에 직결되는 연결재의 두께가 전지 성능에 있어 주요 변수임을 확인하였다. 일정 두께로 고정된 조건 하에 연결재 폭을 변화시킨 경우, 전지 성능은 상대적으로 큰 차이를 보이지 않았다. 이는 본 연구에서 고려한 SOFC의 관형 구조 특성상 연결재의 폭으로는 원주 방향으로 흘러가는 전류 경로를 효과적으로 단축시킬 수 없기 때문으로 사료된다.

• 전기화학회지
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• 제12권4호
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• pp.329-334
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• 2009

본 연구는 연료전지 운전시 전극 촉매 및 전해질막 내에서 발생하는 연료 및 산화제의 산화/환원 반응 메커니즘, 이동현상, 구성품 열화현상 등을 핵자기 공명 (NMR, Nuclear Magnetic Resonance)을 이용하여 연료전지의 분해나 시료 채취 없이 제자리 (in situ) 분석할 수 있는 진단장치용 연료전지 개발에 관한 것이다. NMR에 사용되는 연료전지는 특수하게 제작된 TCD (Toroid Cavity Detector) 탐침 내부에서 작동하여야 하며, TCD 탐침이 가지는 기하학적 제한 요소들로 인해 일반적인 평판형 연료전지와 달리 원통형으로 제작된다. 이로 인해 반응물의 공급이나 생성물의 제거가 어려우며 누수 현상 및 불균일한 압력 분배가 발생하여 성능이 낮다. 따라서, in situ NMR 분석용 연료전지가 가지는 구조상의 특징인 원통형에 적합한 유로를 설계하고 제작하여 물질 전달 특성을 개선해야 할 필요성이 있다. 본 연구에서는 NMR 장비 내의 자기장에 영향을 미치지 않는 비자성 물질을 이용해 원 통형 공기극 유로를 개발하여, 산소의 공급 및 반응물의 제거를 원활하게 하였다. 또한, 체결 압력을막-전극 접합체에 균일하게 분배하여 누수 및 누액을 차단하였다. 이를 통해, 상온에서 약 $36mW/cm^2$의 우수한 성능을 나타내는 in situ NMR 진단용 직접 메탄올연료전지 시스템을 개발하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.2070-2075
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• 2004

Performance of a solid oxide fuel cell (SOFC) can be enhanced by converting thermal energy of its high temperature exhaust gas to mechanical power using a micro gas turbine (MGT). A MGT plays also an important role to pressurize and warm up inlet gas streams of the SOFC. In this study, the influence of performance characteristics of the tubular SOFC on the hybrid power system is discussed. For this purpose, detailed heat and mass transfer with reforming and electrochemical reactions in the SOFC are mathematically modeled, and their results are reflected to the performance analysis. The analysis target is 220kWe SOFC/MGT hybrid system based on the tubular SOFC developed by Siemens-Westinghouse. Special attention is paid to the ohmic losses in the tubular SOFC counting not only current flow in radial direction, but also current flow in circumferential direction through the anode and cathode.

• Korean Chemical Engineering Research
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• 제50권3호
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• pp.562-566
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• 2012

본 논문에서는 세그먼트 관형 고체산화물 연료전지(SOFC)의 설계 및 제작과 특성 분석을 다루고 있다. 관형 세라믹 지지체는 압출 공정을 통하여 제작하였으며, NiO-YSZ 연료극과 YSZ 전해질은 담금 코팅법을 통해 세라믹 지지체에 코팅하였다. 코팅된 세라믹 지지체를 $1,350^{\circ}C$에서 5시간 동안 열처리하였으며, $10{\mu}m$ 미만의 치밀하고, 균열이 없는 YSZ 전해질 층을 얻을 수 있었다. 또한 열처리된 세라믹 지지체에 LSM-YSZ/LSM/LSCF로 구성된 다층 구조 공기극을 담금법으로 코팅하여 $1,150^{\circ}C$에서 열처리하였다. 세라믹 관형 지지체에 코팅된 세그먼트 SOFC 셀은 Ag-glass 연결재를 사용하여 전기적으로 직렬 연결하였으며, 수소연료 유량과 운전 온도에 따른 세그먼트 SOFC의 성능 변화를 측정하였다.