• 한국도로학회:학술대회논문집
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• 2009.11a
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• pp.391-396
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• 2009

• Clean Technology
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• v.25 no.1
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• pp.63-73
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• 2019

Numerical analysis was done to evaluate the chemical reaction and the reduction rate inside of selective non-catalytic reduction to denitrification in combustion process. The $NO_X$ reduction in selective non-catalytic reduction is converted to not only nitrogen but also nitrous oxide. Simultaneous $NO_X$ reduction and nitrous oxide generation suppressing is required in selective non-catalytic reduction because nitrous oxide influences the global warming as a greenhouse gas. The current study was performed compare the computational analysis in the same temperature and amount of NaOH, and in comparison with the previous research experiments and confirmed the reliability of the computational fluid dynamics. Additionally, controlling the addition amount of NaOH to predict the $NO_X$ reduction efficiency and nitrous oxide production. Numerical analysis was done to check the mass fraction of each material in the measurement point at the end of selective non-catalytic reduction. Experimental Value and simulation value by numerical analysis showed an error of up to 18.9% was confirmed that a generally well predicted. and it was confirmed that the widened temperature range of more than 70% $NO_X$ removal rate is increased when the addition amount of NaOH. So, large and frequent changes of the reaction temperature waste incineration facilities are expected to be effective.

• Journal of the Korean Institute of Landscape Architecture
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• v.41 no.6
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• pp.107-116
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• 2013

This study was undertaken to investigate the characteristics of retention and evapotranspiration in the extensive greening module of sloped and flat rooftops for stormwater management and urban heat island mitigation. A series of 100mm depth's weighing lysimeters planted with Sedum kamtschaticum. were constructed on a 50% slope facing four orientations(north, east, south and west) and a flat rooftop. Thereafter the retention and evapotranspiration from the greening module and the surface temperature of nongreening and greening rooftop were recorded beginning in September 2012 for a period of 1 year. The characteristics of retention and evapotranspiration in the greening module were as follows. The water storage of the sloped and flat greening modules increased to 8.7~28.4mm and 10.6~31.8mm after rainfall except in the winter season, in which it decreased to 3.3mm and 3.9mm in the longer dry period. The maximum stormwater retention of the sloped and flat greening modules was 22.2mm and 23.1mm except in the winter season. Fitted stormwater retention function was [Stormwater Retention Ratio(%)=-18.42 ln(Precipitation)+107.9, $R^2$=0.80] for sloped greening modules, and that was [Stormwater Retention Ratio(%)=-22.64 ln(X)+130.8, $R^2$=0.81] for flat greening modules. The daily evapotranspiration(mm/day) from the greening modules after rainfall decreased rapidly with a power function type in summer, and with a log function type in spring and autumn. The daily evapotranspiration(mm/day) from the greening modules after rainfall was greater in summer > spring > autumn > winter by season. This may be due to the differences in water storage, solar radiation and air temperature. The daily evapotranspiration from the greening modules decreased rapidly from 2~7mm/day to less than 1mm/day for 3~5 days after rainfall, and that decreased slowly after 3~5 days. This indicates that Sedum kamtschaticum used water rapidly when it was available and conserved water when it was not. The albedo of the concrete rooftop and greening rooftop was 0.151 and 0.137 in summer, and 0.165 and 0.165 in winter respectively. The albedo of the concrete rooftop and greening rooftop was similar. The effect of the daily mean and highest surface temperature decrease by greening during the summer season showed $1.6{\sim}13.8^{\circ}C$(mean $9.7^{\circ}C$) and $6.2{\sim}17.6^{\circ}C$(mean $11.2^{\circ}C$). The difference of the daily mean and highest surface temperature between the greening rooftop and concrete rooftop during the winter season were small, measuring $-2.4{\sim}1.3^{\circ}C$(mean $-0.4^{\circ}C$) and $-4.2{\sim}2.6^{\circ}C$(mean $0.0^{\circ}C$). The difference in the highest daily surface temperature between the greening rooftop and concrete rooftop during the summer season increased with an evapotranspiration rate increase by a linear function type. The fitted function of the highest daily surface temperature decrease was [Temperature Decrease($^{\circ}C$)=$1.4361{\times}$(Evapotranspiration rate(mm/day))+8.83, $R^2$=0.59]. The decrease of the surface temperature by greening in the longer dry period was due to sun protection by the sedum canopy. The results of this study indicate that the extensive rooftop greening will assist in managing stormwater runoff and urban heat island through retention and evapotranspiration. Sedum kamtschaticum would be the ideal plant for a non-irrigated extensive green roof. The shading effects of Sedum kamtschaticum would be important as well as the evapotranspiration effects of that for the long-term mitigation effects of an urban heat island.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2016.10a
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• pp.79-79
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• 2016

• JOURNAL OF ELECTRICAL WORLD
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• s.346
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• pp.21-35
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• 2005

• Proceedings of the Korean Institute of Landscape Architecture Conference
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• 2011.03a
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• pp.165-168
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• 2011

• Proceedings of the Korean Institute of Landscape Architecture Conference
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• 2011.03a
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• pp.39-42
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• 2011

• Proceedings of the Korea Water Resources Association Conference
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• 1997.05a
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• pp.525-530
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• 1997

• Journal of the Korean Institute of Landscape Architecture
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• v.47 no.6
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• pp.67-77
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• 2019

The purpose of this study is to analyze how much particulate matter at the center of the urban park is reduced compared to the entrance of the park, where the particulate matter problem is serious. It also endeavored to analyze the relationship between the space closure rate and particulate matter reduction rate in the center of the park through the collection and analysis of experimental data. Seven flat land type urban neighborhood parks in Suseong-gu, Daegu were measured at the same place for three days. The research results are as follows. First, the center of the urban neighborhood park had an average temperature 1.05℃ lower than at the entrance and an average humidity of 2.57% higher. Second, the rate of fine dust reduction was PM1- 17.09%, PM2.5- 17.65%, PM10- 14.99%. As for the reduction rate of particulate matter, the smaller the size of the park, the greater the reduction rate. In addition, the reduction rate at the center of the park was lower on days when particulate matter concentration based on the weather reports was low. The higher the concentration at the park entrance, the higher the reduction rate was. Third, a higher the rate of space closures at the center of the park resulted in a higher effect of particulate matter reduction. Noting this, the relationship between particulate matter reduction and the space closure rate in urban neighborhood parks was clearly shown. We hope to be the basis for more extensive experimental data collection.

• Proceedings of the KIEE Conference
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• 2006.10d
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• pp.104-106
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• 2006

Slotless BLDC motor는 Slot과 Teeth가 없으므로 이에 따른 Cogging Torque 및 Torque Ripple이 거의 존재 하지 않으며, 전동기의 무게 또한 감소하게 된다. 또한 권선의 장주(Span)가 짧아 Inductance가 낮기 때문에 고속화가 용이해지며, Slot의 부재는 좀 더 많은 Coil권선을 이용 할 수 있다. 하지만 모터의 구조상 전기장하가 높아짐에 따라 권선의 온도 상승에 대한 보완 등이 필요로 되어 지고 있다. 따라서 본 논문에서는 온도 상승 문제를 해결하기 위해 열 발생과 모터사이의 관계 규명을 전류 밀도 함수로 표시 하였고, 전류 밀도 최소화 설계 방법을 제안하였다. 퍼미언스법에 의한 간략 설계에 의해서 기본 설계를 실시 한 후 FEM을 통한 정밀 해석을 통해서 각각의 민감도를 분석하여 최적의 파라메타를 선정하는 방식을 취하였다. 또한 고속 회전시 발생되는 진동을 저감하기 위해 모터의 길이방향 즉 적층과의 관계를 통하여 진동 저감 설계를 제안하였다.