• 설비공학논문집
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• 제23권12호
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• pp.799-804
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• 2011

Radioactivity of high concentrations have existed in the handling nuclear materials in hot cell of PIEF(Post Irradiation Examination Facility). The exhaust filtration system was enabled to process cylindrical filters by using a manipulator in the hot cell. By establishing a double filtration system with two filters, backup protection against leakage or failure of the first is provided by the second filter. Additionally, this a arrangement is arrange intended to increase the total filtration efficiency. The result of the pressure drop changing in the air flow of the cylindrical and HEPA filters is observed by a curved line. A filtering efficiency of more than 99.99% to $0.3{\mu}m$ particle appears in the upstream and downstream during the efficiency test on the HEPA filters. The V-pleats type had a lower pressure drop than the separator type. There was no damage during usage and was found to be suitable with high capacity of air volume. Therefore, by carrying out performance tests of the exhaust filtration system, efficiency and safety can be achieved.

• 한국수소및신에너지학회논문집
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• 제24권1호
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• pp.70-75
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• 2013

It has fabricated membrane electrode assemblies (MEA) for proton exchange membrane fuel cell by hot-pressing method. The hot-pressing was used for the fabrication of MEA which is composed of commercial platinum electrode on carbon paper. The performance of MEA was studied with different fabrication conditions of temperature, pressure and torque. As the temperature increased, the performance of MEA was increased. and started to decrease l after arrived at the maximum performance of MEA. This is related with good contact between electrode and polymer electrolyte membrane at high temperature and microstructural change at much higher temperature. Similarly, as the pressure increased, the performance of the MEA increased up to highest values and start to decrease. According to the our results, the maximal performance of the MEA was at the temperature of $140^{\circ}C$ and the pressure of $1.5{\times}10^3$ kPa. The optimal torque to assemble the single stack was 3.2 N m.

• 전기화학회지
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• 제2권4호
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• pp.190-194
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• 1999

고분자전해질형 연료전지에서 에칭한 Nafion막으로 고분자막/전극 어셈블리를 제조하고 그 성능을 측정하였다. 에칭을 함으로서 고분자막과 전극의 접합이 잘 이루어져 hot pressing 압력과 온도를 낮출 수 있었고, 낮은 온도에서 hot pressing이 이루어짐으로서 전지의 성능을 향상시킬 수 있었다. 어셈블리 제조방법중의 하나인 페인팅 방법에서 에칭 된 Nafion막을 이용하면 전지의 성능이 향상됨을 보였으며, 에칭정도에 따라 적당한 양의 전극촉매를 사용해야 함을 보였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.25-26
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• 2007

In this paper, we studied the shadow effect which is one of environmental cause for hot-spot phenomenon on PV by considering electrical effects. We fabricated PV module in case of existence and nonexistence of bypass diode. And maximum output power and thermal distribution was analyzed by shadowing solar cell by increase of 5%. From the results, the PV module's(without bypass diode) maximum output power was reduced by hot-spot gradually. But the PV module's(with bypass diode) maximum output power had no reduction by operation of bypass diode, though solar cell is shadowed more than 60%. The solar cell temperature of PV module(without bypass diode) was $10^{\circ}C$ higher compared to module's one. This is a reason for shortening of durability of PV module.

• 공업화학
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• 제30권1호
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• pp.62-67
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• 2019

본 연구에서는 2 kW급 SOFC (solid oxide fuel cell)에서 배출되는 고온 배기가스의 폐열회수를 위한 일체형 Hot BoP의 설계와 성능 분석에 대한 연구를 수행하였다. Hot BoP 시스템은 스택 배기가스의 연소를 위한 촉매 연소기와 연소 후 배기가스의 폐열회수를 위한 원통다관형 공기예열기 및 스팀발생기로 구성되었다. 시스템 설계에서 폐열회수 시스템의 배치에 따른 최대 허용열용량을 산출하여 열분배 공정을 분석하였으며, 열전달 방정식을 통하여 공기예열기 및 스팀발생기의 상세설계를 수행하였다. Hot BoP는 방열손실의 저감을 위해 일체형으로 제작되었으며, SOFC와 연계운전을 가정한 스택배기가스를 모사하여 성능실험에 사용하였다. Hot BoP 성능실험에서 부하별 열전달량 및 시스템 효율이 측정 및 분석되었으며, 당량비에 따른 배기가스의 CO 발생량을 측정하여 연소성을 분석하였다. 실험결과로써, 2 kW급 SOFC 정격운전시 배기가스 연소열부하 기준으로 hot BoP의 열적 효율은 약 60%이며, 연소 후 배기가스의 CO 발생량은 당량비 0.25 이상에서 급격히 감소되는 것으로 나타났다.

• 한국재료학회지
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• 제30권11호
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• pp.595-600
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• 2020

The photovoltaic properties of perovskite solar cells (PSCs) with a carbon electrode fabricated using different annealing processes are investigated. Perovskite formation (50 ℃, 60 min) using a hot-plate and an oven is carried out on cells with a glass/fluorine doped TiO₂/TiO₂/ZrO₂/carbon structure, and the photovoltaic properties of the PSCs are analyzed using a solar simulator. The microstructures of the PSCs are characterized using an optical microscope, a field emission scanning electron microscope, and an electron probe micro-analyzer (EPMA). Photovoltaic analysis shows that the energy conversion efficiency of the samples fabricated using the hot-plate and the oven processes are 2.08% and 6.90%, respectively. Based on the microstructure of the samples and the results of the EPMA, perovskite is formed locally on the carbon electrode surface as the γ-butyrolactone (GBL) solvent evaporates and moves to the top of the carbon electrode due to heat from the bottom of the sample during the hot plate process. When the oven process is used, perovskite forms evenly inside the carbon electrode, as the GBL solvent evaporates extremely slowly because heat is supplied from all directions. The importance of the even formation of perovskite inside the carbon electrode is emphasized, and the feasibility of oven annealing is confirmed for PSCs with carbon electrodes.

• 한국해양바이오학회지
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• 제10권2호
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• pp.53-61
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• 2018

Sargassum fulvellum (gulfweed) is a widespread seaweed in the coastal areas of northeast Asia. In the present study, we identified the phenolic compounds present in aqueous and ethanolic extracts of S. fulvellum and evaluated their antioxidative properties and their abilities to block cell proliferation using in vitro assays: antioxidant activity was assessed by using a DPPH assay and superoxide anion scavenging activity, anti-tyrosinase activity, and anti-proliferative activity were assessed using MTT and lactate dehydrogenase [LDH] assays in vascular smooth muscle cells. The hot-water ($65^{\circ}C$) extract had a higher phenol content than the ethanolic extract. The hot-water extract showed a statistically significant increase in free radical scavenging activity and a greater ability to reduce proliferation of vascular smooth muscle cells stimulated with platelet-derived growth factor-BB. Taken together, hot-water extracts of S. fulvellum may be an important source of antioxidative and antiproliferative agents.

• 방사성폐기물학회지
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• 제2권1호
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• pp.1-11
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• 2004

한국원자력연구소에서는 고온의 용융염 매질 하에서 사용 후 핵연료를 환원시키는 차세대관리종합공정 연구를 수행 중에 있다. 추후 본 기술개발을 실증시험 하기 위해서는 방사선 차폐능이 확보된 핫셀이 필수적이며, 핫셀은 최대 1,385TBq의 방사능량에 대한 차폐 안전성을 가져야 한다. 최대 방사선원에 대한 핫셀의 차폐능을 확보하기 위하여, 본 연구에서는 실증시험 시 사용후핵연료부터 발생하는 중성자 및 감마선에 의한 선량률이 법적 허용선량치보다 낮게 유지되도록 핫셀의 차폐 설계에 대한 안전성을 평가하였다. QAD-CGGP 및 MCNP-4C 코드를 이용하여 핫셀 차폐체의 설계치에 대한 차폐 계산을 수행하였다. 작업구역에 대한 감마선 차폐계산 결과 QAD-CGGP 코드는 2.10${\times}$$10^{-3}$, 2.97${\times}$$10^{-3}$ mSv/h, MCNP-4C 코드는 1.60${\times}$$10^{-3}$, 2.99${\times}$$10^{-3}$ mSv/h 이었으며, 서비스 구역은 1.01${\times}$$10^{-2}$, 7.88${\times}$$10^{-2}$ mSv/h 로 평가되었다. 그리고 MCNP-4C코드를 이용하여 중성자에 의한 선량률을 계산한 결과, 중성자에 의한 선량률은 감마에 의한 선량률의 약 20% 이하치를 나타내었다. 따라서 선량률 대부분은 감마선에 의한 영향임을 알 수 있었다. 본 연구를 통하여 핫셀의 차폐 설계치가 작업구역의 선량 제한치 0.01 mSv/h 와 서비스 구역에서의 선량 제한치 0.15 mSv/h를 만족시키는 것을 확인할 수 있었다.

• Journal of Korean Vacuum Science & Technology
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• 제6권2호
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• pp.71-75
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• 2002

GaAs polycrystalline thin films with good performance were prepared on conducting glass by hot wall epitaxy (HWE), which were used for solar cell. Electron probe micro-analyzer (EPMA) was applied for the composition, morphology of surface and cross-section of grown films, and X-ray diffraction (XRD) for their phase structure; Raman scattering spectum (RSS) and photoluminescence (PL) were used for evaluating their optical characteristics. The results show that, there is textured structure on the surface of grown GaAs polycrystalline films, which is greatly promised to be suitable for the candidate of solar cell with low cost and high efficiency. It is concluded that the source and substrate at temperature of 900 ~ 930 $\^{C}$ and 500 $\^{C}$ respectively would be beneficial for such films.

• Design & Manufacturing
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• 제2권6호
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• pp.28-32
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• 2008

Polymer solar cells are a type of organic solar cell (also called plastic solar cell), or organic photovoltaic cell that produce electricity from sunlight using polymers. It is a relatively novel technology, they are being researched by universities, national laboratories and several companies around the world. In this paper, stamping mold of barrier ribs for polymer solar cells was manufactured by lithography and electroforming which can control the height of pattern and 80nl of barrier ribs was manufactured by using hot embossing.