• 멤브레인
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• 제13권3호
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• pp.154-161
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• 2003

본 연구에서는 소수성 PTFE (Polytetrafluoroethylene) 분리막의 산소동위원소 분리특성을 확인하기 위해 물의 온도에 따른 수증기의 막 투과특성을 Air Cap Membrane Distillation (AGMD)과 Vacuum Enhanced Membrane Distillation (VEMD) 방법을 이용하여 각각 측정하였다. 투과된 수증기는 트랩에서 수거하여 투과플럭스 (permeation flux)를 측정하였고$ H_2^{16}O$와 $H_2^{18}O$의 성분비는 다이오드 레이저 흡수분광법을 이용하여 측정하였다. 분리막을 투과한 수증기에서 무거운 산소동위원소의 성분비가 감소함을 확인하였고 분리계수는 실험 조건에 따라 1.004~1.01로 측정되었다. 또한 분리막의 기공에 있는 공기가 산소동위원소의 분리에 미치는 영향을 확인하였고 기공내 공기가 없을 때 동위원소 분리계수가 증가함을 관찰하였다.

• 한국식품조리과학회지
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• 제18권2호
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• pp.173-178
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• 2002

본 연구는 표고버섯의 비타민 D$_2$함량을 증가시키기 위해 표고버섯의 자실체 안쪽에 자외선 B파를 0, 2.5, 5.0, 7.5, 10.0 J/$\textrm{cm}^2$ 조사하여 버섯내 비타민 D$_2$함량 변화를 측정하였으며 열풍건조시 자외선 B파 조사 시기를 달리하여 천일건조 버섯과 열풍건조 버섯의 비타민 D$_2$함량의 변화를 비교하여 다음과 같은 결론을 얻었다. 1. 자외선 B파 조사 부위(자실체 안쪽과 바깥쪽)에 따른 표고버섯내 비타민 D$_2$함량은 각각 유의적인 차이가 있었다. 즉 버섯 자실체의 안쪽에 자외선 B파를 조사하였을 때 비타민 D$_2$함량이 더욱 증가하였다. 2. 0, 2.5, 5, 7.5, 10.0 J/$\textrm{cm}^2$의 자외선 B파 조사로 비타민 D$_2$함량은 각각 21.51, 120.78, 144.38, 168.08, 187.69$\mu\textrm{g}$/g로 측정되었다. 즉 자외선 조사량에 의해 비타민 D$_2$함량도 유의적으로 증가하였다(p〈0.05). 3. 열풍건조시간에 따라 버섯내 비타민 D$_2$함량이 변화되어 열풍건조 시간이 길어질수록 비타민 D$_2$함량이 대조군에 비해 모두 유의적으로 감소하였다. 4. 자외선 B파 조사 & 열풍건조 복합군은 천일건조군과 열풍건조군 버섯에 비해 유의적으로 비타민 D$_2$함량이 증가하였다.

• Asian Journal of Atmospheric Environment
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• 제8권1호
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• pp.15-24
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• 2014

The capital city of Himalayan Country Nepal, Kathmandu Valley is surrounded by consecutive high mountains, which limits the air distribution and mixing effects significantly. It in turn generates steady air flow pattern over a year except in monsoon season. The air shed in the Valley is easily trapped by the surrounded mountains and the inversion layer formulated as the cap. The $PM_{10}$ concentration was noticeably higher than the standard level (120 ${\mu}g/m^3$) in urban and suburban area of Kathmandu valley for all seasons except monsoon period. The Valley area experiences similar wind patterns (W, WWS, and S) for a year but the Easterly wind prevails only during the monsoon period. There was low and calm wind blows during the winter season. Because of this air flow structure, the air emission from various sources is accumulated within the valley air, high level of air pollution is frequently recorded with other air polluted cities over the world. In this Valley area, brick kilns are recognized as the major air pollution source followed by vehicles. Mostly Bull Trench Kiln (BKT), Hoffman Kiln and Vertical Shaft Brick Kiln (VSBK) are in operation for brick firing in Kathmandu valley where the fuels such as crushed coal, saw dust, and natural gas are used for processing bricks in this study. Tool for the Reduction and Assessment of Chemical and Other Environmental Impacts (TRACI) was used for screening and quantifying the potential impacts of air emission from firing fuels. The total Environmental Performance Score (EPS) was estimated and the EPS of coal was approximately 2.5 times higher than those of natural gas and saw dust. It is concluded that the crushed coal has more negative impact to the environment and human health than other fuel sources. Concerning the human health and environment point of view, alternative environment friendly firing fuel need to be used for brick industry in the kiln and the air pollution control devices also need to be applied for minimizing the air emissions from the kilns.

• 자원ㆍ환경경제연구
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• 제18권3호
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• pp.393-430
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• 2009

이 연구는 미국 에너지 산업의 두 환경 정책 적용 아래 이산화황 농도를 평가하기 위하여 계산가능한 부분적 균형(computable partial equilibrium) 모형을 이용한다. 배출 최고한도(emission caps) 정책과 교환기능 허가(tradable allowances) 정책은 동일한 방출 총계를 산출하기 위해 선택되었다. 두 정책을 통해 상당히 다른 지역간 농도차를 확인할 수 있다. 이러한 편차는 개별 주 및 전국적으로 건강 손상의 총계로 있는 수 억의 달러의 다른 형태의 손실로 변환된다. 배출 최고한도 정책이 교환가능 허가 정책을 4억 5,200만 달러만큼 능가한다. Caps는 다른 정책보다는 8억 4,000만 달러 적은 피해를 전달하는 남서지역 중남부와 남동 국가를 선호한다. 그러나 북부와 북동 국가에 3억 9,000만 달러 더 높은 피해를 전달한다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.863-868
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• 2008

In accordance with the guidelines on the balcony structure changes in December 2005, most of tenants were moving into apartment housing, expand the balcony, but some large deviation between the price construction costs set of cases, due to overuse and the cause of the dispute, and the housing law amended in 2007 due to price cap system is implemented, the cost of expansion the balcony overdose pointed out that there is set to boost the sale price has been raised. These issues in order to improve the government in January 2008, the "Note costs by the balcony expansion" suggested guidelines to protect the rights of tenants and wants to promote the settlement of the sale price cap system. This study calculated the "Note costs by the balcony expansion" window system based on double or single, high performance insulation window system of the quantitative performance analysis of each type window that purpose.

• Journal of Astronomy and Space Sciences
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• 제33권4호
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• pp.305-311
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• 2016

The spatial size and variation of Arctic sea ice play an important role in Earth's climate system. These are affected by conditions in the polar atmosphere and Arctic sea temperatures. The Arctic sea ice concentration is calculated from brightness temperature data derived from the Defense Meteorological Satellite program (DMSP) F13 Special Sensor Microwave/Imagers (SSMI) and the DMSP F17 Special Sensor Microwave Imager/Sounder (SSMIS) sensors. Many previous studies point to significant reductions in sea ice and their causes. We investigated the variability of Arctic sea ice using the daily sea ice concentration data from passive microwave observations to identify the sea ice melting regions near the Arctic polar ice cap. We discovered the abnormal melting of the Arctic sea ice near the North Pole during the summer and the winter. This phenomenon is hard to explain only surface air temperature or solar heating as suggested by recent studies. We propose a hypothesis explaining this phenomenon. The heat from the deep sea in Arctic Ocean ridges and/or the hydrothermal vents might be contributing to the melting of Arctic sea ice. This hypothesis could be verified by the observation of warm water column structure below the melting or thinning arctic sea ice through the project such as Coriolis dataset for reanalysis (CORA).

• Nuclear Engineering and Technology
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• 제32권5호
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• pp.433-445
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• 2000

The interfacial area concentration (IAC) is one of the most important parameters in the two-fluid model for two-phase flow analysis. The IAC can be measured by a local conductivity probe method that uses the difference of conductivity between water and air/steam. The number of sensors in the conductivity probe may be differently chosen by considering the flow regime of two-phase flow. The four sensor conductivity probe method predicts the IAC without any assumptions of the bubble shape. The local IAC can be obtained by measuring the three dimensional velocity vector elements at the measuring point, and the directional cosines of the sensors. The five sensor conductivity probe method proposed in this study is based on the four sensor probe method. With the five sensor probe, the local IAC for a given referred measuring area of the probe can be predicted more exactly than the four sensor probe. In this paper, the mathematical approach of the five sensor probe method for measuring the IAC is described, and a numerical simulation is carried out for ideal cap bubbles of which the sizes and locations are determined by a random number generator.

• 한국대기환경학회지
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• 제24권4호
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• pp.383-392
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• 2008

In order to clarify the influence of the change of urban surface albedo on mesoscale meteorological factors during the summertime, numerical experiments with various albedo of urban surface were carried out. Numerical model used in this study is PSU/NCAR MM5 V3.6. As a result of the numerical simulation intended of Busan assumed the increase of albedo of roofs, buildings, or roads, the increase of albedo can make decrease radiation effect of surface, so that it caused drops in ambient air temperature from $0.5^{\circ}C$ to $1^{\circ}C$ on the average, and the downtown of Busan formed along the trough presented a substantial drop in ambient air temperature about $1.5^{\circ}C$. Modeling studies suggest the increased surface albedo in urban area can reduce surface and air temperatures near the ground and affect related meteorological parameters such as winds and the depth of the mixed boundary layer.

• 한국농림기상학회지
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• 제6권3호
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• pp.164-169
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• 2004

A spatial interpolation scheme incorporating local geographic potential for cold air accumulation (TOPSIM) was used to test the feasibility of operational frost warning in Chatancheon basin in Yeoncheon County, where the introduction of new crops including temperate zone fruits is planned. Air temperature from April to June 2003 was measured at one-minute intervals at four locations within the basin. Cold-air accumulation potentials (CAP) at 4 sites were calculated for 3 different catchment scales: a rectangular area of 65 x 55 km which covers the whole county, the KOWACO (Korea Water Corporation) hydrologic unit which includes all 4 sites, and the sub-basins delineated by a stream network analysis of the digital elevation model. Daily minimum temperatures at 4 sites were calculated by interpolating the perfect prognosis (i.e., synoptic observations at KMA Dongducheon station) based on TOPSIM with 3 different CAPs. Mean error, mean absolute error, and root mean square error were calculated for 45 days with no precipitation to test the model performance. For the 3 flat locations, little difference was detected in model performance among 3 catchment areas, but the best performance was found with the CAPs calculated for sub-basins at one site (Oksan) on complex terrain. When TOPSIM loaded with sub-basin CAPs was applied to Oksan to predict frost events during the fruit flowering period in 2004, the goodness of fit was sufficient for making an operational frost warning system for mountainous areas.

• 한국항공운항학회지
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• 제20권4호
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• pp.14-20
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• 2012

A properly determined separation minima applied in Air Traffic Management(ATM) is critical for safe and efficient aircraft operations. The separation minima is primarily determined by the accuracy performance of surveillance system, and, due to the stringent aviation safety standard, the position accuracy of the surveillance system must be estimated with a high level of reliability. This study proposed a method for estimating the position accuracy of surveillance system with a relatively small amount of data by finding upper confidence limit instead of maximum likelihood values of unknown parameters. Through the proposed method, it is possible to determine a required separation minima with a more reliability in the face of data scarcity which often occurs when we implement a new surveillance system such as Automatic Dependent Surveillance-Broadcast (ADS-B).