• The Korean Journal of Air & Space Law and Policy
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• v.23 no.1
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• pp.189-206
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• 2008

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2010.04a
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• pp.162-164
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• 2010

• Particle and aerosol research
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• v.7 no.2
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• pp.49-57
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• 2011

High concentration of PM10 was reported on late July, 2005 in Seoul along with high particulate ion concentrations in PM2.5. To identify the reason for the severe air pollution episode, time series analysis of the PM10 concentration in the monitoring sites over Korea, wind sector analysis, trend analysis of the ion concentrations, and air mass trajectory analysis were carried out. It was found that the episode could be classified into two separate periods; first one between July 22 and 27 and second one between July 28 and 31. During the first period, the PM10 concentrations at Seoul were in good correlation with the PM10 concentration three hours before at Chuncheon. Trajectory analysis showed that air mass moved from north and turned to west at Kangwon province to Seoul. The concentrations of PM10 mass and ionic species were lower than the second period. During the second period, air mass moved from northern China to Seoul directly and the PM10 concentrations all over the mid-Korean peninsula showed the same trend. These observations suggest that the air pollution during the second period was affected by direct transport of air pollutants from northern China. Thus, the air quality at Seoul during both periods were influenced by long-range transport from outside rather than by local sources, but with different transport patterns.

• The monthly packaging world
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• s.187
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• pp.96-101
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• 2008

• 복합운송
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• s.125
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• pp.32-33
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• 1999

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.33-36
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• 2008

The transient behavior of a passive air breathing direct methanol fuel cell (DMFC) operated on vapor-feeding mode is studied in this paper. It generally takes 30 minutes after starting for the cell response to come to its steady-state and the response is sometimes unstable. A mathematical dynamic one-dimensional model for simulating transient response of the DMFC is presented. In this model a DMFC is decomposed into its subsystems using lumped model and divided into five layers, namely the anodic diffusion layer, the anodic catalyst layer, the proton exchange membrane (PEM), the cathodic catalyst layer and the cathodic diffusion layer. All layers are considered to have finite thickness, and within every one of them a set of differential-algebraic governing equations are given to represent multi-components mass balance, such as methanol, water, oxygen and carbon dioxide, charge balance, the electrochemical reaction and mass transport phenomena. A one-dimensional, isothermal and mass transport model is developed that captures the coupling between water generation and transport, oxygen consumption and natural convection. The single cell is supplied by pure methanol vapor from a methanol reservoir at the anode, and the oxygen is supplied via natural air-breathing at the cathode. The water is not supplied from external source because the cell uses the water created at the cathode using water back diffusion through nafion membrane. As a result of simulation strong effects of water transport were found out. The model analysis provides several conclusions. The performance drop after peak point is caused by insufficiency of water at the anode. The excess water at the cathode makes performance recovery impossible. The undesired crossover of the reactant methanol through the PEM causes overpotential at the cathode and limits the feeding methanol concentration.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.8
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• pp.713-721
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• 2014

In Europe and USA, new programs called GRC(Green Rotorcraft) and SRW (Subsonic Rotary Wing program) respectively, have been currently underway for developing the next generation rotorcraft. The final goal is to develope fuel-efficient/environmental-friendly tilt-rotor civilian rotorcraft, which can partly replace short-range regional aircrafts. Also for safe operation, the new rotorcraft technology is cooperated with the new air transport management(ATM) system, called SESAR(Single European Sky ATM Research) and NextGen(Next Generation Air Transport System) in Europe and USA. In addition to achieve the final goal, the tilt-rotor aircraft, they are trying to improve the performance of conventional helicopters by adopting more efficient propulsion system, active rotor system, and reducing internal and external noise. Especially in GRC program of Europe, the environmental factors such as noise, fuel efficiency, reduction of emission gas(CO2, NOx), are focused for the new technologies.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.3
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• pp.253-259
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• 2007

Standard design and suitable environmental test method should be applied to increase the reliability of UAV flight control systems. UAV flight control systems under development domestically have enough capabilities for complicated missions. However, most low cost systems are not designed with concepts of compatibility, adaptability, and environmental compliance. This paper explains ATR(Air Transport Rack) standard that is widely used on aircraft. The paper presents a design uses commercial off-the-shelf parts. The paper also presents various environmental standards for airborne equipments, including U.S. military specifications. The developed FCS was tested under these specifications. The paper shows the test procedures and results.

• Journal of Korean Society of Transportation
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• v.27 no.5
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• pp.75-82
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• 2009

Air transport markets are composed of airlines' networks through their base airports. The analysis of an air transport market has been focusing on determining the efficiency or competitiveness of airports or airlines in the market using number of routes, number of passengers, transfer rates, revenues, costs, and other data. However, little work has been done in analyzing the airport network itself. Assuming the air transport markets of Korea, China, and Japan are integrated, this paper aims to analyze the characteristics of the resulting airport network. To that end, the degree of connectivity, the degree of closeness, and the betweenness of centrality are employed. The analysis shows that Incheon International Airport is better than most other airports in terms of the degree of connectivity and that of closeness. Airports in Japan, however, exhibit strong connectivity but weak closeness and betweenness of centrality. Although it has low connectivity, Shenyang Airport has a possibility of becoming an attractive point of the integrated market in the future due to its high degree of closeness.

• Journal of Korean Society for Atmospheric Environment
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• v.15 no.2
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• pp.211-217
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• 1999

Data on ambient levels of $SO_2$, $NO_x$, and their emissions in Northeast Asia with special emphasis on China are collected and discussed. Also, study results on long-range transport of air pollutants in the region were briefly discussed. It was found that emissions of air pollutants in China are dominant over the region.