• The Korean Journal of Zoology
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• v.32 no.3
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• pp.232-241
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• 1989

Two cytosol malate dehydrogenase allelomorphs are found in the Dark Chub, Zacco temmincki, a freshwater fish inhabiting Korean waters. Mdh-1MM(hereafter referred to as A-type) is distributed along the south and southeastern parts of Korea, whereas the B-type(Mdh-1MS) is found everywhere except the southeast. Several syrnpatric populations can be found in the southern areas with no hybridization between them. The pattern of geographic distribution would indicate that A-type is superior adaptation to colder water temperature; this is collaborated by evidence collected from a sympatric length of the Tongchon stream, Namhae. The relative warmth of the water along this portion of the stream's length was determined its altitude and the time of year. Frequency of B-types found was directly proportional to the relative warmth of the water and inversely proportional to the nurnber of A-types found in the sarne station. Current data tends to suggest that the B-type of Zacco temrnincki first differentiated from Zacco platypus approximately one million years ago (Yang et al., 1984) while A-type subsequently branched from B-type 300,000 years later(Yang and Mm, 1987) through a progressive adaptation toward colder temperature.

• Korean Journal of Agricultural and Forest Meteorology
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• v.8 no.3
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• pp.145-151
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• 2006

The purpose of this study was to analyze the relationship between the annual variation in diameter growth of Quercus spp. and climatic factors such as monthly temperature, precipitation and solar radiation in central and northern Korea. Annual diameter growth was measured by using stem cores of 262 Quercus trees, and the correlation between the diameter growth and the climatic factors was analyzed. Mean diameter growth of Quercus spp. in Jungwangsan was larger than that in Woraksan, and mean diameter growth by the species was large in order of Q. serrata>Q. variablis>Q. mongolica>Q. dentata. The diameter growth pattern of Quercus spp. in Woraksan was different from that in Jungwangsan. Positive correlations between diameter growth of Quercus trees and temperature or the solar radiation during July were found in Jungwangsan. Significant correlations between diameter growth and solar radiation during March and precipitation during June were found in Woraksan. It is suggested that climatic factors similarly affect the diameter growth of Quercus spp. in a mountainous terrain, but influences of the climatic factors depend on other environmental conditions such as altitude, topography and soil depth.

• Korean Journal of Ecology and Environment
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• v.47 no.3
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• pp.146-159
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• 2014

In this study, we evaluated the temporal changes of water quality in the 90 reservoirs in Korea and the relationships between water quality and their environmental factors in the reservoirs for effective management of reservoirs. The majority of study reservoirs were categorized as the eutrophic state based on Carlson's trophic index. Among 90 reservoirs, more than 55.0% were nutrient-rich based on $TSI_{TP}$ in each month, where more than 50.0% were nutrient-rich based on $TSI_{Chl-a}$ from June to November. Seasonal Mann-Kendall test was used to analyze temporal variation of water quality in the selected 60 reservoirs using monthly data from 2004 to 2008. The results showed that 27 (45.0%) reservoirs showed the improvement of water quality based on TP and Chl-a concentrations, while 14 (23.3%) and 11 (18.3%) reservoirs displayed the degradation of water quality based on TP and Chl-a concentrations, respectively. Meanwhile, a self-organizing map classified the study reservoirs into five groups based on differences of hydrogeomorphology (altitude, catchment area, bank height, lake age, etc.). Physicochemical factors and land use/cover types showed clear differences among groups. Finally, hydrogeomorphology of reservoirs were related to water quality, indicating that the hydrogeomorphological characters strongly affect water quality of reservoirs.

• Journal of the Korean Society of Propulsion Engineers
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• v.9 no.3
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• pp.127-132
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• 2005

In order to investigate transient behavior, of the CRW(Canard Rotor Wing) type UAV(Uninhabited Aerial Vehicle) propulsion system during flight mode transition considering flow control valve operation, the propulsion system was modelled using SIMULINK commercial program. The valve system is to control the gas flow of the rotary duct system and the main duct system, and the analysis was performed with an assumption that the total gas mass flow of the main engine is the same as summation of the rotary duct flow and the main duct flow, and with consideration of valve loss, flow rate and effective area in valve angle variation. The performance analysis was carried out during flight mode transitions from the rotary flight mode to the fixed wing flight mode and vice versa mode at altitude of 1km, flight Mach number 0.1 and maximum engine rpm.

• KSBB Journal
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• v.9 no.3
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• pp.299-305
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• 1994

Taxol contents in various parts of 15 years old yew tree were determined. The descending order of taxol content per unit mass was stem bark, root bark, needle and seed. In the seed, that order was seed coat, embryo and endosperm. The total amount of taxol extractable from a 15 years old yew tree was 1.68 gram. This amount was distributed in needle, stem bark, root bark and seeds as 48.0, 23.8, 27.9 and 0.4%, respectively. Altitudinal variation of taxol content was also observed. More taxol was observed in yew trees grown at high altitude over 1000m above sea level. Calli and suspension cultures were induced from various yew trees. The presence of taxo] in cultured cells was established bv HPLC. The taxol content in cultured cells were different according to the source of explants. These results may be useful for the goal of large scale taxol production by cultured yew tree cells.

• Journal of Ecology and Environment
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• v.41 no.6
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• pp.165-172
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• 2017

Background: This study investigated the temporal variation in soil $CO_2$ efflux and its relationship with soil temperature and precipitation in the Quercus glauca and Abies koreana forests in Jeju Island, South Korea, from August 2010 to December 2012. Q. glauca and A. koreana forests are typical vegetation of warm-temperate evergreen forest zone and sub-alpine coniferous forest zone, respectively, in Jeju island. Results: The mean soil $CO_2$ efflux of Q. glauca forest was $0.7g\;CO_2\;m^{-2}\;h^{-1}$ at $14.3^{\circ}C$ and that of A. koreana forest was $0.4g\;CO_2\;m^{-2}\;h^{-1}$ at $6.8^{\circ}C$. The cumulative annual soil $CO_2$ efflux of Q. glauca and A. koreana forests was 54.2 and $34.2t\;CO_2\;ha^{-1}$, respectively. Total accumulated soil carbon efflux in Q. glauca and A. koreana forests was 29.5 and $18.7t\;C\;ha^{-1}$ for 2 years, respectively. The relationship between soil $CO_2$ efflux and soil temperate at 10 cm depth was highly significant in the Q. glauca ($r^2=0.853$) and A. koreana forests ($r^2=0.842$). Soil temperature was the main controlling factor over $CO_2$ efflux during most of the study period. Also, precipitation may affect soil $CO_2$ efflux that appeared to be an important factor controlling the efflux rate. Conclusions: Soil $CO_2$ efflux was affected by soil temperature as the dominant control and moisture as the limiting factor. The difference of soil $CO_2$ efflux between of Q. glauca and A. koreana forests was induced by soil temperature to altitude and regional precipitation.

• Journal of the Korea Institute of Military Science and Technology
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• v.18 no.4
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• pp.469-477
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• 2015

In this study, the characteristics of main wind direction, vertical temperature and wind speed profile near the Moseulpo airfield for HALE UAV(High Altitude Long Endurance Unmaned Aerial Vehicle) is investigated. The results are summarized as follows, main wind direction is governed by air mass according to season and local wind such as land-sea breeze. The directions of landing and take-off of HALE UAV will be selected as the south-east direction in June ~ August, north-west direction in October ~ March, and south-east direction at daytime in April ~ May, September. Annual variation of temperature at 100 hPa showed that temperature in summer season is lower than winter season. On the other hands, wind speed at 250 hPa in winter season is higher than summer season. The threshold values of temperature and wind speed for HALE UAV flight are $-75^{\circ}C$ and $90ms^{-1}$, which were determined by 5 % frequency value($1.96{\sigma}$), respectively.

• Korean Journal of Environmental Biology
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• v.23 no.1
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• pp.71-88
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• 2005

This study has been monthly carried out to investigate the community structure and seasonal variations of Coleoptera from April to September, 2004 in Mt. Yeonyeop area, Gangwon-do, Korea. A total of 3053 individuals belonging to 358 species in 49 families have been collected in the studied area by light trap, pitfall trap and sweeping methods. The abundant families, based on the number of species, were Carabidae (50 species), Chrysomelidae (40 species) and Curculionidae (40 species). The number of species were highest at site 4, located in low altitude and contained stream. The number of individuals were highest at site 2, because many beetles were attracted by pitfall traps. The total number of species and individuals was highest in July. Nicrophorus (Nicrophorus) quadripunctatus (13.00%) was a dominant species and Synuchus (Synuchus) cycloderus (7.17%) was sub dominant species. Especially Damaster mirabilissimus mirabilissimus, a protected species by government, was collected in May.

• Korean Journal of Remote Sensing
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• v.30 no.5
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• pp.559-570
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• 2014

Backscatter signal observed from the space-borne Light Detection And Ranging (LIDAR) system is providing unique 3-dimensional spatial distribution as well as temporal variations for atmospheric aerosols. In this study, the continuous observations for aerosol profiles were analyzed during a years of 2012 by using a Cloud-Aerosol LIDAR with Orthogonal Polarization (CALIOP), carried on the Cloud-Aerosol LIDAR and Infrared Pathfinder Satellite Observation (CALIPSO) satellite. The statistical analysis on the particulate extinction coefficient and depolarization ratio for each altitude was conducted according to time and space in order to estimate the variation of optical properties of aerosols over Northeast Asia ($E110^{\circ}-140^{\circ}$, $N20^{\circ}$ $-50^{\circ}$). The most frequent altitudes of aerosols are clearly identified and seasonal mean aerosol profiles vary with season. Since relatively high particle depolarization ratios (>0.5) are found during all seasons, it is considered that the non-spherical aerosols mixed with pollution are mainly exists over study area. This study forms initial regional 3-dimensional aerosol information, which will be extended and improved over time for estimation of aerosol climatology and event cases.

• Solar Energy
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• v.20 no.1
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• pp.45-54
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• 2000

Five direct/diffuse decomposition models were validated using the eight years data set of direct normal beam insolation measured in Seoul. The comparison has been performed In terms of the widely used statistical indicators such as MBE, RMSE, CV(RMSE), t-Statistic and Degree of Agreement. Result indicates that most of the correlations exhibit a tendency to underestimate the direct normal beam insolation except Bouguer's model. Most of big discrepancies between the measured and the predicted values was mainly shown in near the sunrising and the sunset period. Even though the investigated five models showed fairly large disagreement for the measured values by 34%$\sim$48% of CV(RMSE), Udagawa's correlation which includes the effect of solar altitude variation appears to performs always better in every statistical error tests.