• Journal of Chest Surgery
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• v.39 no.7 s.264
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• pp.505-510
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• 2006

Background: Small animal cardiopulmonary bypass (CPB) model would be a valuable tool for investigating path-ophysiological and therapeutic strategies on bypass. The main advantages of a small animal model include the reduced cost and time, and the fact that it does not require a full scale operating environment. However the rat CPB models have a number of technical limitations. Effective maintenance and control of core temperature by a heat exchanger is among them. The purpose of this study is to confirm the effect of rectal temperature maintenance using a heat exchanger of cardioplegia system in cardiopulmonary bypass model for rats. Material and Method: The miniature circuit consisted of a reservoir, heat exchanger, membrane oxygenator, roller pump, and static priming volume was 40 cc, Ten male Sprague-Dawley rats (mean weight 530 gram) were divided into two groups, and heat exchanger (HE) group was subjected to CPB with HE from a cardioplegia system, and control group was subjected to CPB with warm water circulating around the reservoir. Partial CPB was conducted at a flow rate of 40 mg/kg/min for 20 min after venous cannulation (via the internal juglar vein) and arterial cannulation (via the femoral artery). Rectal temperature were measured after anesthetic induction, a ter cannulation, 5, 10, 15, 20 min after CPB. Arterial blood gas with hematocrit was also analysed, 5 and 15 min after CPB. Result: Rectal temperature change differed between the two groups (p<0.01). The temperatures of HE group were well maintained during CPB, whereas control group was under progressive hypothermia, Rectal temperature 20 min after CPB was $36.16{\pm}0.32^{\circ}C$ in the HE group and $34.22{\pm}0.36^{\circ}C$ in the control group. Conclusion: We confirmed the effect of rectal temperature maintenance using a heat exchanger of cardioplegia system in cardiopulmonary bypass model for rats. This model would be a valuable tool for further use in hypothermic CPB experiment in rats.

• Korean Journal of Environmental Biology
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• v.27 no.2
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• pp.183-190
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• 2009

Characterization of the analysis of forest vegetation, soil environmental conditions and water quality were performed from March 2003 to March 2007. The two basins were characterized by cultivated area (Kaesim reservoir) and mountain area (Jangchan reservoir), and divided into eleven small basins, where dynamics of pollutants, forest vegetation and soil environmental conditions were surveyed. The vegetation can be divided into 10 types by $Z\ddot{u}rich$-Montpellier school's method. Pearson coefficients between vegetation type and water quality were correlated with dissolved oxygen (DO) in the Quercus variabilis community at the 5% level and total phosphorus (TP) in the Larix leptolepis plantation at the 1% level. Especially total phosphorous and total nitrogen increased in small basins where the proportion of cultivated and residential area increased. The analysis of influences of pollutant discharge on water quality showed that pollutant charge was very low in forest land area ($Y_{T-P}$=-0.0017X+0.2215, r=0.16, $Y_{COD}$=- 0.0395X+8.5051 r=0.47). The soil types of western area were comparatively simple, but those of eastern area were complicated with regosols, red-yellow soils, lithosoles, etc. The pH, total solid (TS) and volatile substance (VS) of the forest and agricultural land soils collected in each site were 5.4~6.9, 75.8~80.2%, and 3.80%~5.80%, respectively. According to the analytical result of soil environmental conditions, heavy metal contents fell short to the mean value of natural conditions. Runoff amount (Y) and depth of topsoil (X) were negatively correlated, $Y_{ron}=-1.0088X_{top}+35.378$ (r=0.68). The correlation was much lower in up-stream but much higher in down-stream, because permeation into soil particle was larger on down-stream due to its more or less gentle slope. Pearson coefficients between soil pH and water pH were statistically significant at 1% level.

• Korean Journal of Remote Sensing
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• v.38 no.5_1
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• pp.497-510
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• 2022

Agricultural reservoirs are essential structures for water supplies during dry period in the Korean peninsula, where water resources are temporally unequally distributed. For efficient water management, systematic and effective monitoring of medium-small reservoirs is required. Synthetic Aperture Radar (SAR) provides a way for continuous monitoring of those, with its capability of all-weather observation. This study aims to evaluate the applicability of SAR in monitoring medium-small reservoirs using Sentinel-1 (10 m resolution) and Capella X-SAR (1 m resolution), at Chari (CR), Galjeon (GJ), Dwitgol (DG) reservoirs located in Ulsan, Korea. Water detected results applying Z fuzzy function-based threshold (Z-thresh) and Chan-vese (CV), an object detection-based segmentation algorithm, are quantitatively evaluated using UAV-detected water boundary (UWB). Accuracy metrics from Z-thresh were 0.87, 0.89, 0.77 (at CR, GJ, DG, respectively) using Sentinel-1 and 0.78, 0.72, 0.81 using Capella, and improvements were observed when CV was applied (Sentinel-1: 0.94, 0.89, 0.84, Capella: 0.92, 0.89, 0.93). Boundaries of the waterbody detected from Capella agreed relatively well with UWB; however, false- and un-detections occurred from speckle noises, due to its high resolution. When masked with optical sensor-based supplementary images, improvements up to 13% were observed. More effective water resource management is expected to be possible with continuous monitoring of available water quantity, when more accurate and precise SAR-based water detection technique is developed.

• Journal of the Korean association of regional geographers
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• v.9 no.2
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• pp.203-216
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• 2003

The process of constructing coastal digital elevation model(DEM), for the 3 dimensional analysis, is composed by abstracting land layers for land elevation and water depth, reprojecting UTM, relocating geographical grid, and interpolating works. The geomorphic set of shallow sea, including tidal current, tidal zone deposition, and water depth distribution, was analyzed by eye search of Landsat TM image, masking of land zone, band combination and regression analysis. Some horizontal differences, between combined DEM and surveyed data of shallow sea, was corrected for analysis. Analyzed geomorphic elements are stream channel, alluvial fan, coastal terrace, tidal current. and shallow sea bank. Results of analysis present that transported fluvial materials influence tidal sedimentation, especially from Gahwacheon river, for the role of artificial draining flooding waters from Jinyang Reservoir, almost in the summer season. In the coastal area with less tidal current, more fine materials are deposited. The influence of currental deposition are higher on small pockets with west coast of well developed terraces. The lower skirt of alluvial fans developed into the tidal zone of shallow sea. Small pocket type bays are closed by coastal current, and less influenced from tidal deposition. The bank of Jinju Bay are developed originally from submerging of remnant erosional mountain ranges, and play on the role of trapping fine materials.

• Korean Journal of Environment and Ecology
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• v.26 no.3
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• pp.313-321
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• 2012

To analyze the bird communities by the land use type, we surveyed 43 plots in Siheung City, Korea from Mar. 2009 to Feb. 2010 and classified the community by TWINSPAN and DCA. Classification result by TWINSPAN was classified into 4 communities. In the first division, waterbirds, such as spot-billed duck(Anas poecilorhyncha) and great egret(Egretta alba) operated as the differential species. In the second and third division, little grebe(Tachybaptus ruficollis) and eurasian sparrow(Passer montanus) were operated as the differential species. The relationship between land use types and classified bird communities, all plots of community I were located in the forest. Community II plots were contained all urban and several semi-natural land use types. Community III contains stream and rice paddy. Plots in the reservoir were classified community IV. The stream and rice paddy were classified into different communities, which were colsely related with the size of wetland paddy. Community III had the highest species diversity index and community II had lowest. Community III also had the highest maximum species diversity index and evenness index. The result of this study, small stream and small rice paddy located within the city have insignificant characteristics as the habitat for birds. Management size of semi-natural land use for wildbird habitat in the urban area should be considered for showing their habitat characteristics. If the classification of biotope type based on the scale of rice paddy and urban park and the type of landuse type in the riverside then we should be consider the standard of minium area.

• Journal of Korea Water Resources Association
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• v.41 no.1
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• pp.65-74
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• 2008

The small and medium sized dams have the fill dam type of a lot of occasions, which are often weak in cases of major floods. For this reason, although a countermeasure is in great need, due to the importance of the facilities and financial situations, no direct safety measures have been taken. In this study, in order to minimize construction expenditure for practical safety measures in cases of major floods, the overflow section of spillway has been analyzed focusing on how the overflow capacity will increase in the case of partially rebuilding a part of the overflow section of spillway favorable for hydraulic conditions. The Labyrinth weir and movable weir was chosen for reconstruction models of the overflow section. Moreover, for analyzing the after-effects of the reconstruction, a small scale dam was temporarily chosen for various experiments such as the hydraulic model testing and the three dimension numerical evaluation through the use of Flow-3D.

• Korean Journal of Ecology and Environment
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• v.38 no.2 s.112
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• pp.237-248
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• 2005

To determine the content of hazard microcystin (MC) in Han River system and Ecological Ponds in Seoul City and Kyunggi district, a most toxic derivative, microcystin-LR (MCLR) of 15 samples of 7 ponds, 4 rivers and 4 reservoirs during low precipitation and cold season in 2003 were analyzed by ELISA method. With the change of water temperature ($0.4\;{\sim}\;21.9^{\circ}C$), cyanobacteria including Microcystis aeruginosa dominated the cold phytoplankton community in small ecological ponds such as Kyungbokgung Kyunghyaeru (KBP), Seokchon reservoir (SCR), Yangsoori Ryukgakji (YSS), having the long residence time. Contents of MCLR (the detection limit; $0.05\;{\mu}g\;L^{-1}$) were high in cyanobacteria-rich sites, especially, Microcystis aeruginosa. Total MCLR, cell extracted type plus dissolved type, were $1.39\;{\mu}g\;L^{-1}$ in KBP, $0.55\;{\mu}g\;L^{-1}$ in SCR and $0.59\;{\mu}g\;L^{-1}$ in YSS, in the first sampling having a high temperature (>$20^{\circ}C$), while some detected only in YSS during the cold season. As expected, the MCLR content was correlated with Microcystis aeruginosa (r = 0.526 for cell extracted type, r = 0.433 for dissolved type). Therefore, low concentration of MCLR detected in small ponds and Han river system in Seoul metropolitan city and Kyunggi district, maybe hardly affect human recreation activity, especially the drinking water supply.

• Fisheries and Aquatic Sciences
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• v.9 no.4
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• pp.160-166
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• 2006

We explored the possibilities of using the freshwater rotifer Brachionus angularis as a live food for small fishes cultured in fresh- or brackish waters. Brachionus angularis were collected from a reservoir for isolation and laboratory culture. Length and width of the lorica were $102.3{\mu}m$ and $76.6{\mu}m$, respectively, and those of amictic eggs were $64.4{\mu}m\;and\;47.9{\mu}m$, respectively. When their growth rates were examined at six different temperatures, i.e., 15, 20, 25, 30, 35, and $40^{\circ}C$, the highest daily growth rate of 0.801 was observed at $35^{\circ}C$, and growth was lower with decreasing temperature. Adaptation to salinity change was evaluated with two different modes of salinity increase: step-wise elevation lasting for short durations of 5 to 30 min or a long duration of 24 h. With the short duration modes, no individuals survived salinity higher than 10 psu, and the number of live individuals did not increase throughout the experiment. However, in the 24-h elevation, the number of individuals increased when salinity was elevated by 1 to 2 psu per day for the first 2 or 3 days, while no increase in number occurred at salinity increments higher than 3 psu per day. In addition, to assess the effect of different diets, four single-component diets (Chlorella vulgaris, Nannochloris sp., baker's yeast, or dry yeast) and three combination diets (C. vulgaris + Nannochloris sp. + baker's yeast + dry yeast; C. vulgaris 70% + baker's yeast 30%; C. vulgaris 30% + baker's yeast 70%) were used. The specific growth rates of B. angularis fed combination diets were higher than those of rotifers fed any single-component diet, with the highest rate of 0.648 in B. angularis fed a mixture of C. vulgaris, Nannochloris sp., baker's yeast, and dry yeast, and the lowest rate of 0.200 in those fed dry yeast only. Our results indicate that the freshwater rotifer B. angularis can be used for seedling production of both freshwater and brackish-water fishes that require small (less than about $120{\mu}m$) live food during their early stages.

• Journal of Korea Water Resources Association
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• v.37 no.8
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• pp.643-651
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• 2004

In this paper, the Hydrologic Simulation Program-Fortran (HSPF) was validated to estimate the pollutant loads from rural small watershed. The study watershed was the HP#6 subwatershed in Balhan reservoir watershed, located southwest from Suwon. The drainage area of HP#6 study watershed was 3.85$\textrm{km}^2$. Parameters of the HSPF model related to hydrology and water quality were calibrated from 1996 to 1997, and validated from 1999 to 2000 using observed hydrologic and water quality data. The average simulated runoff ratio for the calibration period was 0.579 and the measured runoff ratio was 0.583. The root mean square error (RMSE) for runoff during the calibration period was 2.1mm and correlation coefficient ($R^2$) was 0.92. Regarding the total nitrogen simulation, the RMSE was 0.086kg/ha/day and $R^2$ was 0.81 for the calibration period. In the case of total phosphorus, the RMSE was 0.012kg/ha/day and $R^2$ was 0.70 for the calibration period.

• Geophysics and Geophysical Exploration
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• v.12 no.3
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• pp.239-245
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• 2009

To verify the reinforcing effect of grouting materials composed of colloid cement and ordinary portland cement on the water leakage region in a small scale dike, we performed a tubecasing method and applied surface electrical resistivity survey including electrical resistivity tomography (ERT) to find resistivity variation before and after grouting. Hydraulic conductivities after grouting show 10 times lower than those of before grouting. These variation indicates that the cement grout blocks the leakage pathway effectively. As the results of dipole-dipole resistivity survey along the dike, resistivity distribution after grouting did not represent noticeable spatial variation in time. Resistivity monitoring results at the dike with vertical electrical sounding (VES) showed that the region of decreasing apparent resistivity was occupied by the grout after grouting. Predicted resistivities from the inversion of ERT data well matched with results of VES at the same regions. From the ERT using check holes to inspect the effect of grouting, we could find that the ERT is quite effective to identify spatially the grout region in a dike.