• 한국가스학회지
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• 제11권1호
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• pp.51-54
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• 2007

78개 셀의 전극유효 면적이 $295cm^{2}$인 고분자 전해질 연료전지(PEMFC) 스택의 운전특성과 CO 피독에 대한 영향을 조사하였다. 전류밀도 $325mA/cm^{2}$에서 출력 5.4kW를 6시간 유지시키는 동안 셀들의 전압편차는 2.3%로 매우 안정함을 보였다. 개질과정의 부산물로 생성되는 CO는 PEHFC의 성능에 중요한 영향을 끼치는 스택의 주 오염물질중의 하나이다. 시간에 따른 연속적인 CO 피독 실험(5-20ppm)은 스택의 피독과 재생과정의 route를 알 수 있었다.

• 반도체디스플레이기술학회지
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• 제18권1호
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• pp.1-4
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• 2019

Reactive sputtering is widely used because of its high deposition rate and high step coverage. The deposition layer is often affected by target poisoning because the target conditions are changed, as well, by reactive gases during the initial stage of sputtering process. The reactive gas affects the deposition rate and process stability (target poisoning), and it also leads unintended oxide interlayer formation. Although the target poisoning mechanism has been well known, little attention has been paid on understanding the interlayer formation during the reactive sputtering. In this research, we studied the interlayer formation during the reactive sputtering. A DC magnetron sputtering process is carried out to deposit an aluminum oxide film on a silicon wafer. From the real-time process monitoring and material analysis, the target poisoning phenomena changes the reactive gas balance at the initial stage, and affects the interlayer formation during the reactive sputtering process.

• 대한임상독성학회지
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• 제15권1호
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• pp.56-59
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• 2017

Pneumatosis cystoides intestinalis and portomesenteric venous gas are uncommon radiological findings, but are found commonly in cases of bowel ischemia, or as a result of various non-ischemic conditions. A 72-year-old man visited an emergency center with altered mental status 2 hours after ingestion of an unknown pesticide. On physical examination, he showed the characteristic hydrocarbon or garlic-like odor, miotic pupils with no response to light, rhinorrhea, shallow respiration, bronchorrhea, and sweating over his face, chest and abdomen. Laboratory results revealed decreased serum cholinesterase, as well as elevated amylase and lipase level. We made the clinical diagnosis of organophosphate poisoning in this patient based on the clinical features, duration of symptoms and signs, and level of serum cholinesterase. Activated charcoal, fluid, and antidotes were administered after gastric lavage. A computerized tomography scan of the abdomen with intravenous contrast showed acute pancreatitis, poor enhancement of the small bowel, pneumatosis cystoides intestinalis, portomesenteric venous gas and ascites. Emergent laparotomy could not be performed because of his poor physical condition and refusal of treatment by his family. The possible mechanisms were believed to be direct intestinal mucosal damage by pancreatic enzymes and secondary mucosal disruption due to bowel ischemia caused by shock and the use of inotropics. Physicians should be warned about the possibility of pneumatosis cystoides intestinalis and portomesenteric venous gas as a complication of pancreatitis following anticholinesterase poisoning.

• Korean Chemical Engineering Research
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• 제51권3호
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• pp.370-375
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• 2013

상업용 막전극접합체를 사용하여 제작한 고분자전해질 연료전지의 CO poisoning 및 air bleeding 효과가 스택의 셀전압 성능에 미치는 영향을 분석하였다. 실험을 통해 확보한 동적 응답 데이터에 일차 미분방정식으로 표현되는 일차계 모델을 적용하여 정상상태 이득과 시간상수를 계산하는 방법으로 스택 셀전압의 응답 특성을 정량화하였다. 연료전지 개질기로부터 공급되는 개질 가스에 포함된 CO 농도가 1 ppm 증가할 때마다 셀전압은 1.3~1.6 mV 저하되고, CO 농도의 변화폭이 클수록 정상상태에 도달하기까지 걸리는 시간이 점점 짧아지는 것으로 분석되었다. CO poisoning에 의해 저하된 스택 성능을 회복시키기 위해 air bleeding을 수행할 경우, 주입하는 공기의 농도를 증가시킬수록 셀전압 상승폭(정상상태 이득)이 커지고 회복시간(시간상수)은 짧아지나, 1% 수준의 air bleeding만으로도 CO poisoning이 일어나기 전 셀전압의 87%~96%를 1~30 min 이내에 회복시킬 수 있는 것으로 분석되었다.

• 대한금속재료학회지
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• 제56권12호
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• pp.893-899
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• 2018

In the present study, we investigated the sulfur poisoning of the Ni anode in solid oxide fuel cells (SOFCs) as a function of operating conditions. Anode supported cells were fabricated, and sulfur poising tests were conducted as a function of current density, $H_2S$ concentration and humidity in the anode gas. The voltage drop was significant under the higher current density (${\sim}714mA/cm^2$) condition, while it was much reduced under the lower current density (${\sim}389mA/cm^2$) condition, at 100 ppm of $H_2S$. A secondary voltage drop, which occurred only at the high current density, was attributed to Ni oxidation in the anode. Thus, operation at high current density with high $H_2S$ concentration may lead to permanent deterioration in the anode. The effect of water content (10%) on the sulfur poisoning was also investigated through a constant current test (${\sim}500mA/cm^2$) at 10 ppm of $H_2S$. The cell operating with 10% wet anode gas showed a much smaller initial voltage drop, in comparison with a dry anode gas. The present study indicates that operating conditions, such as gas humidity and current density, should be carefully taken into account, especially when fuel cells are operated with $H_2S$ containing fuel.

• 대한임상독성학회지
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• 제4권1호
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• pp.1-6
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• 2006

Purpose: Hemoperfusion is an effective modality of extracorporeal elimination of toxins in acutely poisoned patients. We evaluated the effect of hemoperfusion on plasma concentration of toxins in patients exposed to certain pesticides. Methods: Eleven patients who were acutely exposed to pesticides participated in our study. We measured plasma pesticide concentration from the whole blood obtained by arterial and venous sources by gas chromatography. Results: The plasma concentrations of only 3 patients was measured. Methidation clearance by hemoperfusion was 82.2%, fenitrothion was 23%, and endosulfan was 0% Conclusion: Measurement of plasma organophosphate concentration is not a practical application. Our results suggest that hemoperfusion is applicable in patients with pesticide intoxication according to clinical status.

• 대한임상독성학회지
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• 제15권2호
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• pp.86-93
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• 2017

Purpose: Some advanced countries have reported annual statistics for poisoning based on data from poison control centers. This study was conducted to propose a baseline format and statistics of poisoning in Korea from a national representative database. Methods: This study was a retrospective analysis of poisoning patients based on data from an emergency department (ED) based injury in-depth surveillance project by the Korea Centers for Disease Control and Prevention in 2016. Bite or sting injuries were not included. Variables related to poisoning were summarized using a similar format as the National Poison Data System in the United States. Results: A total of 7,820 poisoning patients presented to 23 EDs. Adults ${\geq}20$ years accounted for 84% of the population, while the proportion of intentional poisoning was 59.4%. The most common poisoning substances were therapeutic drugs (45%), gas (21%), pesticides (15%), and artificial toxic substances (13%). Overall, 34.5% of patients were admitted for further treatment. The mortality was 3.2% (248 cases), and the most common causative substances were carbon monoxide, glyphosate, and paraquat, in order. Conclusion: This study showed the recent status of poisoning in Korea. However, a comprehensive poisoning registry based on poison control centers may be required to provide more accurate national statistics in the future.

• 대한임상독성학회지
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• 제19권2호
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• pp.65-71
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• 2021

Purpose: The purpose of this study was to investigate the cause of acute fatal poisoning and the time of death by analyzing the National Emergency Department Information System (NEDIS) of South Korea. Methods: The NEDIS data from 2014 to 2018 excluding non-medical visits were used for this study. The patients with acute poisoning were extracted using diagnostic codes. The toxic substances were classified into pharmaceuticals, pesticides, gases, artificial poisonous substances, and natural toxic substances. Patients were classified according to the time of death, place of death, and region. In each case, the most causative substances of poisoning were identified. Results: There were 380,531 patients including poisoning-related diagnoses, of which 4,148 (1.1%) died, and the WHO age-standardized mortality rate was 4.8 per 100,000. Analysis of 2,702 death patients whose primary diagnosis was acute poisoning, the most common cause of poisoning death was pesticides (62%), followed by therapeutic drugs, gas, and artificial toxic substances. Herbicides were the most common pesticides at 64.5%. The proportion of mortality by time, hyperacute (<6 h) 27.9%, acute (6-24 h) 32.6%, subacute (1-7 d) 29.7%, and delayed period (>7 d) were 9.8%. Conclusion: This study suggests that the most common cause of poisoning death was pesticides, and 60% of deaths occurred within 24 hours. The 71% of mortality from pesticides occurred within 6-24 hours, but mortality from gas was mostly within 6 hours. According to the geographic region, the primary cause of poisoning death was varied to pesticides or pharmaceuticals.

• 한국가스학회지
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• 제25권3호
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• pp.27-38
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• 2021

본 연구에서는 가스보일러 가동 중 배기통이 이탈하는 상황이 발생했을 때, 시스템적으로 인지하고 자동으로 보일러 가동을 중지하여 일산화탄소를 포함한 유해 배기가스가 실내로 유입되는 상황을 근원적으로 차단하는 방안을 제시하였다: (1) 연소에 필요한 공기량을 제어하기 위해 설치된 풍압센서(APS : Air Pressure Sensor)의 출력전압을 측정하여 배기통의 정상상태와 이탈상태를 감시하는 기능을 추가한다. (2) 배기통이 이탈하면 APS의 출력전압이 상시 운전범위에서 일시적으로 상승하게 된다. 보일러 제어부인 PCB가 이 상태를 배기통 이탈로 간주하여 보일러 가동을 멈추면서 배기통 이탈 상태를 실내온도 조절기에 표시하도록 한다. 또한 국토교통부령으로 정한 「건축물의 설비기준 등에 관한 규칙」에서 명시한 공동주택 및 다중이용시설의 환기시설 기준에 따라, 실내공기 교환횟수에 맞는 풍량을 적용하여 실내공기를 환기하는 실험을 실시하였다. 이 실험 결과 실제 일산화탄소가 실내에 누출된 최악의 상태에서, 중독사고 예방이 가능하다는 것을 확인하였다. 다만, 동 규칙에서 정의한 시간당 실내공기 교환횟수를 기존 0.7회에서 0.5회로 2013년부터 완화하여 운영하고 있는데, 실험결과 8시간 가중평균 노출기준인 TWA 30 ppm을 초과하는 농도가 측정되어 기준을 강화할 필요성이 있다. 본 연구 결과에 기초하여 가스보일러 배기압력의 기계적 인지를 통해 배기통 이탈을 감지하는 기술과 일산화탄소 경보기와 연동된 실내공기 환기시스템 기술을 도입한다면 일산화탄소 중독사고가 크게 감소될 것으로 판단된다. 제조 및 검사단계의 문제점을 보완하고, 올바른 설치 및 수리, 사용자의 배기통 이탈에 대한 관심이 더해졌을 때, 일산화탄소 중독으로 인한 인명사고를 예방하는데 효과적인 대책이 될 것으로 사료된다.

• 한국가스학회지
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• 제11권4호
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• pp.91-97
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• 2007

최근 5년간 가스보일러 사고를 살펴보면 도시가스가 LP가스보다 7.4배 많이 발생하고 있다. 이는 도시 가스보일러사용이 늘어나게 되어 사고율이 증가하는 것으로 보인다. 이러한 보일러 사는 CO 중독에 의한 사고가 87%로 가장 많이 발생하였으며, 타형태의 시보다 인명피해가 4.3배가 높게 나타났다. 따라서 본 연구에서는 CO 중독의 원인인 배기통 분리에 의한 원인을 규명하고, 현재 사용하고 있는 내열실리콘의 성능에 대하여 실험을 통하여 안전성을 입증하자 한다. 실험결과 일반실리콘은 $56^{\circ}C$에 경화가 시작되었으나, 내열실리콘을 $606^{\circ}C$가 되어도 탄화되지 않았다. 또한 배기통의 일반적인 온도인 $150^{\circ}C$에서 일반실리콘은 열화 후 기밀시험에서 누출이 발생하였으나, 내열실리콘은 본래의 성질을 유지하고 있었다. 따라서 배기통 연결부에 내열실리콘을 사용하면 CO 중독으로 인한 인명피해 사고를 줄일 수 있을 것으로 판단된다.