• 한국가시화정보학회지
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• 제19권3호
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• pp.106-114
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• 2021

In the present study, we investigate the flow characteristics of a paraglider canopy with leading-edge tubercles by performing force measurement and surface flow visualizations. The experiment is conducted at Re = 3.3×10⁵ in a wind tunnel, where Re is the Reynolds number based on the mean chord length and the free-stream velocity. The canopy model with leading-edge tubercles has flow characteristics of a two-step stall, showing an earlier onset of the first stall than the canopy model without leading-edge tubercles. However, the main stall angle of the tubercled model is much larger than that of the canopy model without tubercles, resulting in a higher aerodynamic performance at high angles of attack. The delay in the main stall is ascribed to the suppression of separation bubble collapse around the wingtip at high angles of attack.

• 한국작물학회지
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• 제42권4호
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• pp.473-482
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• 1997

Temperature, humidity and wetness duration were monitored for fully developed paddy rice canopies with 3 different structures induced by the seeding method(puddled-soil drill seeding, DS ; hand broadcasting, HB ; machine broadcasting, MB). Within-canopy air temperature averaged over "clear sky" hours during the study period(maximum tillering through heading) was lower than the screen temperature at a nearby standard weather station, especially in the night. The same trend was true for "overcast sky" hours except the diurnal distinction. Vapor pressure within the canopy was high during the daytime and low in the night, making the daytime deviation from outside the canopy more significant on clear days. Under the overcast sky, the canopy maintained a steady 5 to 10％ higher vapor pressure than the outside regardless of day or night. Daily maximum temperature was observed to be higher within the canopies with more leaf mass, making MB the highest, HB the lowest, and DS in between. Relative humidity was over 90％ in the night and dropped to 70％ in the mid-afternoon, but vapor pressure within the canopy was highest at around 13:00 LST. Dew point depression was lowest and, combined with the temperature, the relative humidity was highest in HB. Mean period of wetting duration was in the order of DS＞HB＞MB, while the dew point depression was greatest in DS.

• 한국육종학회지
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• 제40권2호
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• pp.143-152
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• 2008

1913년부터 2000년까지 국내에서 육성된 70품종에 대한 초형형질에 관련된 주경, 분지 및 엽형질의 특성을 파악하여 다수성 콩 품종개발의 기초자료로 이용코자 하였다. 1. 초형형질의 변이는 주경과 분지관련형질의 12개 형질 중에서 초형폭, 분지장 및 초형폭/장 비율이 컸으며, 엽관련 8개형질 중에서는 엽병각, 엽장폭비 및 엽건물중이 컸다. 2. 용도별로 초형폭/장 비율은 밥밑콩이 장류 및 두부용콩과 나물콩에 비하여 높았고 장류 및 두부용콩과 나물콩은 큰 차이가 없었다.총분지장/주경장 비율은 나물콩과 밥밑콩이 높았고 장류 및 두부용콩이 낮았다. 3. 주경과 분지형질은 초형폭/장 비율과 총분지장/ 주경장 비율에 의하여 각각 그룹으로 분류되어졌고, 협초폭형이며 주경의존형은 단원콩, 금강콩, 셀비 및 신팔달콩이었고, 협초폭형이며 분지의존형은 소명콩이었다. 광초폭형이면서 주경의존형은 강림, 금강대립 및 진율콩이었으며, 광초폭형이면서 분지의존형은 검정콩 2호이었다. 4. 용도별로 소엽장/폭 비율은 밥밑콩이 작았고 장류 및 두부용콩과 나물콩과는 큰차이가 없었으며, 복엽의 엽면적은 밥밑콩이 가장 컸고 나물콩이 가장 작았다. 엽병장은 나물콩이 작았으며 장류 및 두부용콩과 밥밑콩은 큰 차이가 없었고, 엽병각은 밥밑콩이 가장 컸고 나물콩이 가장 작았다. 5. 엽형태는 엽장폭비와 엽면적에 의하여 각각 4그룹으로 분류 되어졌고, 소엽장폭비가 큰 원엽이면서 엽면적이 큰 대형엽은 부석과 대황콩이었고, 엽장폭비가 극세엽이면서 엽면적이 작은 소형엽은 은하콩과 소호콩이었다. 6. 엽병의 특성은 엽병장과 엽병각에 의하여 각각 3그룹과 4그룹으로 분류 되어졌고, 엽병장이 짧고 엽병각이 작은 품종은 은하콩이었고, 엽병장이 짧고 엽병각이 큰 품종은 알찬콩, 무한콩 및 푸른콩이었으며, 엽병장이 길고 엽병각이 작은 품종은 신팔달콩 2호이었다. 7. 은하콩은 전 시험품종 중에서 엽장폭비가 가장 큰 극세엽이면서 엽면적이 가장 작은 소형엽이었고, 엽병장이 가장 짧으며 엽병각이 가장 작은 품종이었다.

• Journal of Plant Biology
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• 제23권2호
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• pp.45-48
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• 1980

Effects of habitat and substrate quality on decomposition rate of litters of Larix kaempferi and Quercus serrata were estimated in Kwangnung forest. The amount of organic matter under the canopy of Quercus serrata stand was higher than that under the canopy of Larix kaempferi. The loss constant of litters in the Larix kaempferi stand was higher than that in the Quercus serrata stand.

• Applied Biological Chemistry
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• 제15권1호
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• pp.41-47
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• 1972

새로 육종된 다수성 품종인 IR 667-수원 213과 진흥을 사용하여 출수후 군락구조의 등적 변화를 질소영양과 관련하여 비교분석한 결과 다음과 같았다. 1. 군락주조 패턴 (출수기 건물중 수직분포)은 진흥에서는 수직형이고 IR 667에서는 수평형이었다. 2. 엽면적 밀도 (또는 무게)의 수직분포 패턴이 IR 667은 중앙부 우세형으로 진흥은 상부 우세형으로 분류되었다. 3. 군락구조 보존패턴과 엽면적 백분율 분포패턴은 엽면적밀도의수직분포패턴을 따랐다. 4. 군락보존력은 IR 667이 약하여 군락보존율이 낮으며 이는 엽의노화가 빠른것을 나타낸다. 5. 질소영양이 군락구조패턴에 거의 영향을 주지 않지만 질소의 느린공급(유황입힌요소)은 구조의 중앙부를 보존하여 상부우세형을 중앙부 우세형으로 변환 시키려는 경향을 보였으며 그것이 수량 증가의 원인이 된것같다. 6. 증앙부우세형과 상부우세형은 곡실생산에서의 상위엽의존형과 하위엽 의존형에 각기 잘 적합한것 같다.

• Journal of Ecology and Environment
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• 제44권2호
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• pp.90-97
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• 2020

Background: Natural forests are generally considered to be less prone to biological invasions than other modified ecosystems, particularly when canopy cover is high. Few decades of management of degraded forests by local communities in Nepal has increased canopy cover and altered disturbance regimes. These changes might have reduced the abundance of invasive alien plant species (IAPS) in forests. To understand the status of IAPS in such forests, we studied two community managed Shorea robusta forests (Sundari and Dhusheri) of Nawalpur district in central Nepal. In these two forests, vegetation sampling was done using circular plots 10 m radius at forest edge, gaps, and within canopy. Variation of IAPS richness and cover across these microhabitats were compared, and their variation with tree canopy cover and basal area analyzed. Result: Altogether 14 IAPS were recorded in the study forests; among them Chromolaena odorata, Ageratum houstonianum, and Lantana camara had the highest frequency. Mikania micrantha was at the early stage of colonization in Sundari Community Forest (CF) but absent in Dhuseri CF. Both IAPS cover and richness was higher at forest edge and gap than in canopy plots and both these attributes declined with increasing canopy cover and tree basal area. Conclusion: The results indicate that increase in canopy cover and closure of forest gaps through participatory management of degraded forests can prevent plant invasions and suppress the growth of previously established IAPS in Shorea robusta forests of Nepal. This is the unacknowledged benefit of participatory forest management in Nepal.

• 한국환경과학회지
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• 제9권2호
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• pp.101-108
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• 2000

Through numerical experiment using simplified OSU-1D PBL(Oregon State University One-Dimensional Planetary Boundary Layer) model and field measurement, we studied the impacts of vegetation canopy on heat island that was one of the characteristics of local climaate in urban area. it was found that if the fraction of vegetation was extended by 10 percent, the maximum air temperature and the maximum ground temperature can come down about 0.9${\circ}C$, 2.3${\circ}C$, respectively. Even though the field measurement was done under a little unstable atmospheric condition, the canopy air temperature was lower in the daytime, and higher at night than the air and ground temperature. This result suggests that the extention of vegetation canopy can bring about more pleasant local climate by causing the oasis, the shade and the blanket effect.

• Current Optics and Photonics
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• 제1권2호
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• pp.113-117
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• 2017

With the increasing use of high-power laser diode bars (LDBs) and stacked LDBs, the issue of thermal control has become critical, as temperature is related to device efficiency and lifetime, as well as to beam quality. To improve the thermal resistance of an LDB set, we propose and analyze a bypass heat sink with a top canopy structure for an LDB set, instead of adopting a thick submount. The thermal bypassing in the top-canopy structure is efficient, as it avoids the cross-sectional thermal saturation that may exist in a thick submount. The efficient thickness range of the submount in a typical LDB set is guided by the thermal resistance as a function of thickness, and the simulated bypassing efficiency of a canopy is higher than a simple analytical prediction, especially for thinner canopies.

• 수산해양교육연구
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• 제17권3호
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• pp.404-412
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• 2005

The surface energy budget depends on many factors, such as the type of surface, the soil moisture and the vegetation canopy, the geographical location, daily, monthly and seasonal variations, and weather conditions. In the coastal region, the surface is not homogeneous at various scales for instance water, sand, mud, tall grass, and crops. The energy balance over the vegetation canopy was analyzed with the optical energy balance measuring system. The latent heat flux was more intensive than the sensible heat flux. The sensible heat flux was very small in summer due to the canopy effect and higher in spring and autumn. In summer the development of the atmospheric boundary depended on rather the vertical shear of wind than the sensible heat flux.

• 한국환경과학회지
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• 제31권1호
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• pp.43-50
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• 2022

In this paper, lysimeter was installed to analyze the moisture fluctuations on the surface of a forest. The weight of the soil was measured, and the moisture fluctuations were calculated through the difference in weight over time. The amount of dew condensation on the surface of the ground was about 2-7 mm. January experienced the most dew condensation (7.2 mm). It was found that about 43 mm of dew condensation was generated over one year. To analyze the characteristics of evapotranspiration in the forest, the evapotranspiration on the surface was measured by the lysimeter method and the evapotranspiration on the upper part of the canopy was measured by the eddy covariance method. These results were compared and analyzed. Until mid-October, the evapotranspiration of the forest was active, and the amount of evapotranspiration on the top of the canopy was higher than the amount on the surface. Thereafter, the amount of evapotranspiration on the top of the canopy decreased due to the lowering of temperature and net-radiation. The amount of evapotranspiration on the surface and above the canopy showed the same tendency.