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연료중의 이산화탄소 불순물에 의한 고분자전해질연료전지의 성능변화 연구
서중근,권준택,김준범,Seo, Jung-Geun,Kwon, Jun-Taek,Kim, Jun-Bom 한국전기화학회 2008 한국전기화학회지 Vol.11 No.1
연료전지는 수소를 직접 사용하는 것이 가장 효율이 높지만 가정이나 사무실에서는 수소 저장탱크를 사용하기보다는 도시가스(메탄가스)를 연료 source로 하여 수소를 생산하는 것이 유리하다. 연료전지에 사용하는 수소는 천연가스나 바이오가스, 탄화수소계열의 연료를 개질하여 생산하며 개질반응과정에서 필연적으로 여러 성분의 불순물이 포함되어 있다. CO, $CO_2$, $H_2S$, $NH_3$, $CH_4$등의 불순물이 포함된 수소연료가 PEM fuel cell에 공급되면 연료전지 성능에 영향을 준다고 보고되어 있다. 이러한 영향에는 전극 촉매의 피독에 의한 kinetic losses, 전해질막과 촉매이온층의 양이온 전도성 감소에 의한 ohmic losses 그리고 촉매층의 구조나 소수성 감소에 의한 mass transport losses가 있다. 개질기에서 생산된 수소연료는 약 73%의 $H_2$와 20% 이하의 $CO_2$, 5.8% 이하의 $N_2$, 2% 이하의 $CH_4$, 10ppm 이하의 CO로 최종 공급된다. 본 연구에서는 연료 중에 $CO_2$가 고분자전해질 연료전지 anode측 성능에 미치는 영향을 조사하였다. 실험은 연료전지에 공급되는 연료중에 $CO_2$농도를 10%, 20%, 30%로 전류와 전압의 성능곡선과 장시간(10시간)실험 그리고 임피던스를 측정하였다. 또한 가스크로마토그래피를 이용하여 순수한 수소와 $CO_2$가 함유된 수소의 혼합을 통해 나온 연료전지 inlet에서의 불순물의 농도를 검증하였다. Even though fuel cell have high efficiency when pure hydrogen from gas tank is used as a fuel source, it is more beneficial to generate hydrogen from city gas (mainly methane) in residential application such as domestic or office environments. Thus hydrogen is generated by reforming process using hydrocarbon. Unfortunately, the reforming process for hydrogen production is accompanied with unavoidable impurities. Impurities such as CO, $CO_2$, $H_2S$, $NH_3$, $CH_4$, and $CH_4$ in hydrogen could cause negative effects on fuel cell performance. Those effects are kinetic losses due to poisoning of the electrode catalysts, ohmic losses due to proton conductivity reduction including membrane and catalyst ionomer layers, and mass transport losses due to degrading catalyst layer structure and hydrophobic property. Hydrogen produced from reformer eventually contains around 73% of $H_2$, 20% or less of $CO_2$, 5.8% of less of $N_2$, or 2% less of $CH_4$, and 10ppm or less of CO. This study is aimed at investigating the effect of carbon dioxide on fuel cell performance. The performance of PEM fuel cell was investigated using current vs. potential experiment, long run(10 hr) test, and electrochemical impedance measurement when the concentrations of carbon dioxide were 10%, 20% and 30%. Also, the concentration of impurity supplied to the fuel cell was verified by gas chromatography(GC).
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연료중의 이산화탄소 불순물에 의한 연료전지 성능변화 연구
서중근(Seo, Jung-Geun),권준택(Kwon, Jung-Taek),김준범(Kim, Jun-Bom) 한국신재생에너지학회 2007 한국신재생에너지학회 학술대회논문집 Vol.2007 No.11
Hydrogen could be produced from any substance containing hydrogen atoms, such as water, hydrocarbon (HC) fuels, acids or bases. Hydrocarbon fuels couold be converted to hydrogen-rich gas through reforming process for hydrogen production. Even though fuel cell have high efficiency with pure hydrogen from gas tank, it is more beneficial to generate hydrogen from city gas (mainly methane) in residential application such as domestic or office environments. Thus hydrogen is generated by reforming process using hydrocarbon. Unfortunately, the reforming process for hydrogen production is accompanied with unavoidable impurities. Impurities such as CO, CO₂, H₂S, NH₃, and CH₄ in hydrogen could cause negative effects on fuel cell performance. Those effects are kinetic losses due to poisoning of electrode catalysts, ohmic losses due to proton conductivity reduction including membrane and catalyst ionomer layers, and mass transport losses due to degrading catalyst layer structure and hydrophobic property. Hydrogen produced from reformer eventually contains around 73% of H₂, 20% or less of CO₂, 5.8% of less of N₂, or 2% less of CH₄, and 10ppm or less of CO. Most impurities are removed using pressure swing adsorption (PSA) process to get high purity hydrogen. However, high purity hydrogen production requires high operation cost of reforming process. The effect of carbon dioxide on fuel cell performance was investigated in this experiment. The performance of PEM fuel cell was investigated using current vs. potential experiment, long run (10 hr) test, and electrochemical impedance measurement when the concentrations of carbon dioxide were 10%, 20% and 30%. Also, the concentration of impurity supplied to the fuel cell was verified by gas chromatography (GC).
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실험적 뇌경색의 형태학적 관찰에서 Neutral Red와 Tetrazolium Salt 교차 염색의 의의
서정호,박윤관,김명현,정용구,정흥섭,서중근,이훈갑,주정화,이기찬 대한신경외과학회 1992 Journal of Korean neurosurgical society Vol.21 No.8
Serial changes in the size of infarcted area induced by MCA occlusion(MCAO) were compared with Neutral Red(NR) and 2,3,5-Triphenyl tetrazolium chloride(TTC) stains. The differences in size of the infarcted area as shown by the 2 stains and its significance were also evaluated. The experimental animals were divided into 7 groups, with each group consisting of rats; these groups were stained at 2,4,6,8,12,24 and 48 hours after MCAO. After MCAO, NR was infused into the femoral vein, after which the brain was removed, the frontal pole of the brain cut into 1.5㎜ sections, and each section photographed. Then, the NR-stained sections were immersed in TTC solution for 45 minutes and photographed. Results showed that the infarcted area progressively increased according to time duration after MCAO(one-way ANOVA, p<0.01). Between 4 and 6 hour groups, the difference of the infarcted area was greater than at any other timed groups, this being statisfically significant(unpaired t-test, p<0.05). After 6 hours, the infarcted area with NR stain became relatively stable. In contrast, however, the infracted area with TTC stain did not stabilize, but continued to increase up to 24 hours. Overall, the infarcted area with NR stain was greater than with TTC stain in all the timed groups(paired t-test, p<0.05). As time progressed, the differences tended to decrease 48 hours post occlusion. In our study, serial changes of the ischemic penumbra area were evaluated by staining the ischemic area simultaneously with Neutral red and TTC stain. The results suggest that the ischemic penumbra area may still persist even after 48 hours post-MCAO.
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척추강내에 발생한 혈관지방종 치험 1 예 : 증례보고 Case Report With A Review of The Literature
임동준,박정율,조태형,정흥섭,서중근,이훈갑 대한신경외과학회 1995 Journal of Korean neurosurgical society Vol.24 No.7
Spinal angiolipomas are distinct but rare benign lesions composed of mature lipocytes admixed with abnormal blood vessels that vary from capillary to sinusoid or from venular to arterial in size. They account for 0.14% to 1.2% of all spinal axial tumors. 2% to 3% of extradural spinal tumors, and 16% to 35% of spinal lipomas. The tumors are mostly extradural and have a predilection site in the midthoracic region. The symptoms are usually due to cord compression. Magnetic resornance imaging is the diagnostic choice and surgery is universally successful in relieving the symptoms. The authors report a case of spinal angiolipoma in a 35-year-old female which was successfully treated by operation. A review of the literature on this lesion is also presented.
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