• Journal of Ecology and Environment
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• v.29 no.3
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• pp.205-212
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• 2006

Effects of nitrogen and phosphorus fertilization on nutrient dynamics and litterfall production were determined in adjacent 41-year-old plantations of Pinus rigida Miller and Larix kaempferi Gordon on a similar soil in Yangpyeong, Gyeongggi Province. Litterfall production were significantly different among sampling dates and between the tree species, whereas it was not significantly different among the treatments. Total annual litterfall production was 6,377 kg/ha for P. rigida and 4,778 kg/ha for L. kaempferi, respectively. Litterfall nutrient concentrations of L. kaempferi were higher than those of P. rigida. For both tree species, litterfall nutrient concentrations were highest in summer when the least litterfall production occurred, and lowest in late-autumn when the greatest litterfall production occurred, except for Ca in the L. kaempferi stand. The amount of total organic matter in the forest floor of P. rigida and L. kaempferi plantations were 24,296 kg/ha and 10,763 kg/ha, respectively. Forest floor N and P contents were 126, 10 kg/ha for P. rigida and 102, 8 kg/ha for L. kaempferi, respectively.

• Korean Journal of Ichthyology
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• v.29 no.4
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• pp.235-243
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• 2017

Reproductive characteristics of Rhodeus pseudosericeus (Pisces: Acheilognathinae) was investigated at the Heukcheon (River), Yangpyeong-gun, Gyeonggi-do, Korea from January to July in 2012. This fish prefers heavily vegetated stagnant pool with Phragmites japonica and Salix koreensis and area with high proportions of sand and mud. The standard length of the population indicated that 13~22 mm group is 0-year old, 30~45 mm group is 1-year old, 45~55 mm group is 2-year old and 45~70 mm group is more than 3-year old (June in 2012). The sex ratio of female to male was 1 : 0.80. The spawning season was from March to June with water temperatures in the range $11.0{\sim}26.2^{\circ}C$. The embryos were found with no egg mass in Unio douglasiae sinuolatus and the number of those was 1~22 ($5.8{\pm}5.51$). The number of the embryos found in each of the four parts of the mussel gill was 1~9 ($2.7{\pm}2.16$) in left outer, 1~2 ($1.5{\pm}0.71$) in left outer, 1~5 ($1.8{\pm}1.79$) in left outer and 1~22 ($5.8{\pm}5.51$) in left outer.

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.6
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• pp.548-561
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• 2015

Atmospheric concentrations of polychlorinated dibezo-p-dioxins and furans (PCDD/Fs) were investigated at urban-residential (Group I: Suwon, Guri and Goyang), industrial (Group II: Ansan, Siheung and Bucheon), urban-rural mixed (Group III: Yangju, Pocheon and Dongducheon) and rural regions (Group IV: Yangpyeong) in Gyeonggi-do from February 2012 to November 2012 quarterly. The concentrations of PCDD/Fs ranged from 0.018 to $0.109pgTEQm^{-3}$ in Group I (mean value: $0.061pgTEQm^{-3}$), 0.059 to $0.367pgTEQm^{-3}$ in Group II (mean value: $0.179pgTEQm^{-3}$), 0.072 to $0.836pgTEQm^{-3}$ in Group III (mean value: $0.334pgTEQm^{-3}$) and 0.014 to $0.066pgTEQm^{-3}$ in Group IV (mean value: $0.034pgTEQm^{-3}$), respectively. In spite of the less PCDD/F emission sources than Group II (industrial regions), the level of PCDD/Fs in urban-rural mixed area showed the highest values with high fluctuation. It's likely that the Group III was affected by fugitive emissions such like biomass burning and unregulated open burning. The mean contribution of particle phase to total PCDD/F concentration was above 83% because most of PCDD/F congeners were partitioned into particle phase. We evaluated their gas-to-particles equilibriums with the regression between the particle-gas partition coefficient, $K_P(m^3{\mu}g^{-1})$ and corresponding subcooled liquid vapor pressure ($P_L$). The logarithm-$K_P$ of PCDD/Fs was poorly correlated with $P_L$ at low ambient temperature (below $10^{\circ}C$) and the slope (m) values for log-log plots of the $K_P$ vs. $P_L$ was steeper in the Group 2 and Group 3 than residential area. It implies that the slope values were likely influenced by both the direct emission source of PCDD/Fs and ambient temperature.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.504-511
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• 2020

This paper studies the operational efficiency of the new sesame variety "da u" farmed by the Rural Development Administration. In the survey area--Gyeonggi-do Province, where sesame cultivation was the most intensive. Thirty farmers were surveyed by rural enterprises in the Yangpyeng area where 'da u' was planted. The efficiency of the operation was analyzed by studying the data of 30 farmers. In order to analyze the operational efficiency of the farmers, this survey used the DEA model for analysis in order to determine the technical efficiency of farmers. The result shows that the DEA technical efficiencies of most farmers are efficient, and only 6 farmers are inefficient. The reason for the inefficiency is the high cost of input factors. To analyze the determinants of efficiency through the Tobit model, reducing the pesticides and general fertilizers led to increased technical efficiency. This is inefficient use of pesticides and general fertilizers relative to the output factor, and efficient methods should reduce the cost issues.

• The Journal of the Petrological Society of Korea
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• v.26 no.1
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• pp.13-43
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• 2017

In the Hapcheon area, hypersthene-bearing monzonite (mangerite) and syenite are recognized. The main minerals of syenite are alkali feldspar, plagioclase, amphibole, biotite, and quartz. Anhedral hornblende and biotite are interstitial between feldspar and quartz, indicating that the hydrous minerals were crystallized later on. Based on petrochemical studies of major elements, syenite is alkaline series, metaluminous, and I-type. The variation patterns in the trace and rare earth elements of mangerite and syenite show the features of subduction-related igneous rock such as depletion of HFSE, relative enrichment in LILE to LREE, and negative Nb-P-Ti anomalies. Based on the experimental data and petrographic characteristics of the syenite, Hapcheon syenitic magma is considered to be formed by partial melting in a dry system. SHRIMP U-Pb zircon data yield the Triassic age as $227.4{\pm}1.4Ma$ in mangerite, $215.3{\pm}1.2Ma$ in syenite, and $217.9{\pm}2.6Ma$ in coarse-grained syenite, respectively. The mangerite age is similar to those of post-collisional plutonic rocks in Hongseong (226~233 Ma), Yangpyeong (227~231 Ma), and Odaesan (231~234 Ma) areas in the Gyeonggi Massif. Syenites were intruded after about 10 Ma. The features seen in the mangereite and syenite rocks can be explained by models such as the continental collision and slab break-off and the lithosphere thinning and asthenosphere upwelling model.

• The Korean Journal of Pesticide Science
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• v.15 no.4
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• pp.479-484
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• 2011

The number of comstock mealybug, Pseudococcus comstocki (Kuwana) suddenly increased at ginseng fields in Yangpyeong, Gyeonggi-do from mid July to early August. By the late of September just before digging up the roots of ginseng, more than 8 individuals of the comstock mealybug per plant were occurred and evenly dispersed around the roots. Through the bioassay in the laboratory, six environmental friendly agricultural materials (for example, Nobug, Kkagsami, GB-1, GB-2, GB-3, GB-5) containing sophora extract or paraffin oil as main components were selected by the effective control agents for controlling the comstock mealybug. These selected agents showed a quite similar insecticidal activities to 2 insecticides such as clothianidin and thiamethoxam registered in control of ginseng insect pests. Also. in the ginseng field test, the agent containing sophora extract and paraffin oil, like 2 insecticides showed high control effects against the comstock mealybug.

• Journal of the Korean Association of Geographic Information Studies
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• v.18 no.3
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• pp.35-51
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• 2015

The purpose of this study is to improve the previous groundwater contamination vulnerability assessment method, apply it to the study area, and select priority areas for groundwater management based on the quantitative analysis of groundwater contamination vulnerability. For this purpose, first, the previous 'potential contamination' based on groundwater contamination vulnerability assessment method was upgraded to the methodology considering 'adaptation capacity' which reduced contamination. Second, the weight of groundwater contamination vulnerability assessment factors was calculated based on the analytical hierarchy process(AHP) and the result of survey targeting groundwater experts. Third, Gyeonggi-do was selected as the study area and the improved methodology and weight were implemented with GIS and actual groundwater contamination vulnerability assessment was carried out. Fourth, the priority area for groundwater contamination management was selected based on the quantitative groundwater contamination vulnerability assessment diagram. The improved detailed groundwater contamination vulnerability assessment factors in this study were a total of 15 factors, and 15 factors were analyzed as new and improved weight with higher 'adaptation capacity' than the assessment factor corresponding to the previous 'potential contamination' in the weight calculation result using AHP. Also, the result of groundwater contamination vulnerability assessment in Gyeonggi Province using GIS showed that Goyang and Gwangmyeong which were adjacent to Seoul had a high groundwater contamination vulnerability and Pocheon and Yangpyeong County had a relatively low groundwater contamination vulnerability. In this study, the previous groundwater contamination vulnerability assessment was improved and applied to study areas actually. The result of this study can be utilized both directly and indirectly for the groundwater management master plan at national and local government level in the future.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.4
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• pp.657-669
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• 2018

In recent years, the development of complex urban areas has become saturated and much attention has been focused on the development of underground space, and deep excavation is frequently performed in order to increase the utilization of underground space due to the enlargement of buildings and the high rise of buildings. Therefore, in this study, we tried to understand the behavior of the braced wall and the behavior of the tunnel adjacent to the wall according to the stiffness of the wall and the distance between the tunnel and wall. As a result of the study, the deformation of the braced wall tended to decrease with increasing the stiffness of the wall, and the axial force acting on the struts was also different according to the stiffness of braced wall. When the stiffness of the braced wall is small (2 mm), the point at which the axial force of the braces maximizes is near 0.3H of the wall. When the stiffness of the braced wall is large (5 mm), the axial force is maximum at around 0.7H of the wall. Also, the tunnel convergence occurred more clearly when the separation distance from the braced wall was closer, the stiffness of the wall was smaller, and the tunnel convergence was concentrated to the lower right part. The ground settlement due to the excavation of the ground tended to decrease as the distance between tunnel and braced wall was closer to that of the tunnel, which is considered to be influenced by the stiffness of the tunnel.

• Journal of Korea Water Resources Association
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• v.47 no.11
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• pp.1017-1026
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• 2014

To investigate the effect of upstream dam operation and river water use on the downstream flows, SWAT-K watershed model was applied to the Paldang Dam watershed of the Han River basin. Analysis results from 2001 to 2009 showed that outflows from the multi-purpose dams such as the Soyanggang Dam and Chungju Dam much have a strong influence on the downstream flows during both the low- and high-flow seasons. This resulted an increase of low-flow at the Paldang Dam, the end of Pukhangang, and the Yangpyeong stage station by $100.57m^3/s$, $33.01m^3/s$, and $49.66m^3/s$, respectively. Whereas, the impact of river water use was hardly found in the Pukhangang, and also was not significant in the (Nam)hangang. Therefore, the effect of small dam such as the Hoengseong Dam or river water use would be able be excluded for long-term runoff analysis. But, in the case of the areas with a large amount of water use, a sufficient information such water-intake and water movement also must be taken into account like this study.

• Korean Journal of Plant Resources
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• v.25 no.5
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• pp.550-560
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• 2012

The aim of this study is to research spatial diffusion, a condition for spread of Ailanthus altissima, and conduct flora analysis to provide useful information for management of it. Three research spots where the community dominance value was found to be high and habitat was homogeneous according to a 2010 in-depth species study were selected, and census was conducted using a line-transect method. The diffusion area included 1,435 $m^2$ in Yangpyeong, 1,118 $m^2$ in Gimcheon and 760 $m^2$ in Sancheong, in order of increasing size, and a total of 510 trees were found to be randomly diffused in space. An average of 83.2% of Ailanthus altissima were found to be included in DBH classes I (1.0-3.4 cm) and II (3.5-6.4 cm), showing that young trees were dominant in Ailanthus altissima communities and there was an age diffusion pattern according to degree of disturbance in habitats. A total of 41 families 75 genera and 91 species of flora made up the list, and Therophytes were most widely found in all of the three areas. This shows that habitats in these areas have recently been disturbed. It was evaluated that elimination of roadside population and mountainous area population was necessary to prevent diffusion of Ailanthus altissima.