• Journal of Korean Society of Environmental Engineers
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• v.39 no.3
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• pp.155-163
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• 2017

Membrane filtration has become more popular in drinking water treatment recently, since the filtration can control not only particulate matters but also pathogenic microorganisms such as giardia and cryptosporidium very effectively. Pilot-scale ($120m^3/d$ of treatment capacity) and test-bed ($25,000m^3/d$ of treatment capacity) microfiltration experiments were conducted to find optimum operating mode and the critical flux. Optimum operating mode of pilot-test was assessed as inflow 1.0 min, filtration 36.5 min, air backwash 0.9 min, backwash 1.0 min and outflow 1.0 min with 50 LMH ($L/min{\cdot}m3^$) of critical flux. Critical Flux was calculated to be $50L/m^2-h$ (within TMP 0.5 bar) based on the increase formula of the transmembrane pressure difference according to the change of time at Flux 20, 40, 56 and 62 LMH in pilot operation. Chemical cleaning was first acid washed twice, and alkali washing was performed secondarily, and a recovery rate of 95% was obtained in the test-bed plant. The results of operating under these appropriate conditions are as follows. Turbidity of treated water were 0.028, 0.024, 0.026 and 0.028 NTU in spring, summer, autumn and winter time, respectively. Microfiltration has superior treatment capability and performance characteristics in removing suspended solids and colloidal materials, which are the main cause of turbidity and important carrier of metal elements, and it has shown great potential in being an economically substitute to traditional processes (sand filtration).

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.2
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• pp.311-324
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• 2017

Energy loss at manholes under surcharged flow is considered as one of the major causes of inundation in urban area. Therefore, it is necessary to analyze the flow characteristics to reduce the energy loss in the surcharged four-way combining manhole. In this study, hydraulic experimental apparatus was constructed considering the results of the present survey. Square manholes and pipe diameters were reduced to 1/5 by applying sewer facility standards. Numerical simulations were carried out with the Fluent 6.3 model to derive the invert condition which can reduce the energy loss in the surcharged four-way combining square manhole. The hydraulic experiments were carried out according to the various conditions of the lateral flow rate($Q_{lat}/Q_{out}$), discharge of outflow pipe (2.0, 3.0, 4.0, 4.8 l/sec), and invert shape (rectangle and square open conduit type). The crossed invert was not found to improve the drainage capacity of the surcharged four-way rectangular combining manhole. However, the improved rectangle open conduit type invert and square open conduit type invert were analyzed to improve the drainage capacity by reducing the head loss coefficients by about 8% and 28%, respectively. Therefore, in order to increase the drainage capacity of urban facilities, it is possible to install and use the improved invert proposed in this study.

• Journal of Environmental Impact Assessment
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• v.27 no.2
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• pp.170-180
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• 2018

Highland fields are concentrated in the Jaun area of Hongcheong-gun, a large amount of sediments are discharged from the highland fields. The sediment runoff affect the turbidity and water quality of the Soyang Lake, furthermore adversely affect water supply source of the capital region. There are several kinds of BMPs(Best management practices) to decrease the sedimentrunoff from the highland fields. Although construction cost of multistage sedimentation basins is very high, there is no actual survey data for the removal efficiency of suspended sediments and water quality in our country. In this study, stormwaterinflow and outflow of the multistage sedimentation basins were surveyed, and the removal efficiency of nonpoint source pollutants were analyzed. The stormwater survey results fortwo rainfall events show thatremoval efficiencies of SS, BOD and TP loads in the multistage sedimentation basins are 35%~62%, 24%~55%, 35%~58%, respectively. Although the measured efficiencies of the basins were lower than the theoretical efficiency, the proper operation and management can improve the removal rate of the basins. Turbid water problem in the upper parts of the Soyang River can be managed effectively through the additional installation of multistage sedimentation basins.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.1
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• pp.31-39
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• 1998

As it has been reported that the depolarization induced acetylcholine (ACh) release is modulated by activation of presynaptic $A_1$ adenosine heteroreceptor and various lines of evidence suggest the $A_2$ adenosine receptor is present in the hippocampus. The present study was undertaken to delineate the role of adenosine receptors on the hippocampal ACh release. Slices from the rat hippocampus were equilibrated with $[^3H]choline$ and then the release amount of the labelled product, $[^3H]ACh$, which was evoked by electrical stimulation (rectangular pulses, 3 Hz, 2 ms, 24 mA, $5\;V/cm^{-1}$, 2 min), was measured, and the influence of various adenosine receptor-related agents on the evoked tritium outflow was investigated. And also, the drug-receptor binding assay was performed in order to confirm the presence of $A_1$ and $A_2$ adenosine receptors in the rat hippocampus. N-ethylcarboxamidoadenosine (NECA), a potent adenosine receptor agonist with nearly equal affinity at $A_1$ and $A_2$ adenosine receptors, in concentrations ranging from $1{\sim}30\;{\mu}M$, decreased the electrically-evoked $[^3H]ACh$ release in a concentration-dependent manner without affecting the basal rate of release. And the effect of NECA was significantly inhibited by 8-cyclopentyl-1,3-dipropylxanthine (DPCPX, 2 ${\mu}M$), a selective $A_1$ adenosine receptor antagonist, but was not influenced by 3,7-dimethyl-1-propargylxanthine (DMPX, 5 ${\mu}M$), a specific $A_2$ adenosine receptor antagonist. $N^6-cyclopentyladenosine$ (CPA), a selective $A_1$ adenosine receptor agonist, in doses ranging from 0.1 to 10 ${\mu}M$, reduced evoked $[^3H]ACh$ release in a dose-dependent manner without the change of the basal release. And the effect of CPA was significantly inhibited by 2 ${\mu}M$ DPCPX treatment. 2-P-(2-carboxyethyl)-phenethylamino-5'-N-ethylcarboxamidoadenosine hydrochloride (CGS-21680C), a potent $A_2$ adenosine receptor agonist, in concentrations ranging from 0.1 to 10 ${\mu}M$, did not alter the evoked ACh release. In the drug-receptor binding assay, the binding of $[^3H]2-chloro-N^6-cyclopentyladenosine$ ($[^3H]$CCPA) to the $A_1$ adenosine receptor of rat hippocampal membranes was inhibited by CPA ($K_i$ = 1.22 nM), NECA ($K_i=10.17 nM$) and DPCPX ($K_i=161.86 nM$), but not by CGS-21680C ($K_i=2,380 nM$) and DMPX ($K_i=22,367 nM$). However, the specific binding of $[^3H]CGS-21680C$ to the $A_2$ adenosine receptor was not observed. These results suggest that the $A_1$ adenosine heteroreceptor play an important role in evoked ACh release, but the presence of $A_2$ adenosine receptor is not confirmed in this study.

• Journal of Korea Water Resources Association
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• v.51 no.3
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• pp.263-272
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• 2018

For the design of hydraulic structures, the design flood discharge corresponding to a specific frequency is generally used by using the design storm calculated according to the rainfall-runoff relationship. In the past, empirical equations such as rational equations were used to calculate the peak flow rate. However, as the duration of rainfall is prolonged, the outflow patterns are different from the actual events, so the accuracy of the temporal distribution of the probability rainfall becomes important. In the present work, Huff's quartile method is used for the temporal distribution of rainfall, and the third quartile is generally used. The regression equation for Huff's quadratic curve applies a sixth order polynomial equation because of its high accuracy throughout the duration of rainfall. However, in statistical modeling, the regression equation needs to be concise in accordance with the principle of simplicity, and it is necessary to determine the regression coefficient based on the statistical significance level. Therefore, in this study, the statistical significance test for regression equation for temporal distribution of the Huff's quartile method, which is used as the temporal distribution method of design rainfall, is conducted for 69 rainfall observation stations under the jurisdiction of the Korea Meteorological Administration. It is statistically significant that the regression equation of the Huff's quartile method can be considered only up to the 4th order polynomial equation, as the regression coefficient is significant in most of the 69 rainfall observation stations.

• Atmosphere
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• v.23 no.4
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• pp.425-441
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• 2013

This study investigates the projections of water cycle, budget and river discharge over land in the world at the end of twenty-first century simulated by atmosphere-ocean climate model of Hadley Centre (HadGEM2-AO) and total runoff integrating pathways (TRIP) based on the RCP scenario. Firstly, to validate the HadGEM2-AO hydrology, the surface water states were evaluated for the present period using precipitation, evaporation, runoff and river discharge. Although this model underestimates the annual precipitation about 0.4 mm $mon^{-1}$, evaporation 3.7 mm $mon^{-1}$, total runoff 1.6 mm $mon^{-1}$ and river discharge 8.6% than observation and reanalysis data, it has good water balance in terms of inflow and outflow at surface. In other words, it indicates the -0.3 mm $mon^{-1}$ of water storage (P-E-R) compared with ERA40 showing -2.4 mm $mon^{-1}$ for the present hydrological climate. At the end of the twenty-first century, annual mean precipitation may decrease in heavy rainfall region, such as northern part of South America, central Africa and eastern of North America, but for increase over the Tropical Western Pacific and East Asian region. Also it can generally increase in high latitudes inland of the Northern Hemisphere. Spatial patterns of annual evaporation and runoff are similar to that of precipitation. And river discharge tends to increase over all continents except for South America including Amazon Basin, due to increased runoff. Overall, HadGEM2-AO prospects that water budget for the future will globally have negative signal (-8.0~-0.3% of change rate) in all RCP scenarios indicating drier phase than the present climate over land.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.4
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• pp.479-484
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• 2001

The effect of dietary supplementation of sodium salt of isobutyric acid in low protein (10% CP) wheat straw based diet on nutrient utilization and rumen fermentation was studied in ruminally fistulated male crossbred cattle. The study included a 7 day metabolism and a 3 day rumen fermentation trials. The cattle were distributed into two equal groups of 4 each. The animals of control group were fed a basal diet consisting of wheat straw, concentrate mixture and green maize fodder in 40:40:20 proportion whereas branched chain volatile fatty acid (BCFA) supplemented group received a basal diet + isobutyric acid at 0.75 percent of basal diet. The duration of study was 36 days. The feed intake between experimental groups did not differ significantly and the average total DMI (% BW) was 2.01 and $2.28kg\;day^{-1}$ in control and BCFA supplemented diets. The dietary supplementation of BCFA improved (p<0.05) the DM, OM, NDF and cellulose digestibility by 4.46, 6.63, 10.57 and 11.31 per cent over those fed control diet. The total N retention on BCFA supplementation was improved (p<0.01) due to decreased (p<0.05) urinary N excretion. The concentrations of ruminal total N was 37.07 and $34.77mg\;100ml^{-1}$ in control and BCFA fed groups, respectively. Dietary supplementation BCFA significantly (p<0.01) reduced the ruminal ammonia N concentration as compared to control and the mean values ($mg\;100ml^{-1}$) were 13.18 and 9.42 in control and BCFA fed groups. The total VFA concentration was higher (p<0.01) in BCFA supplemented group (101.14 mM) than the control (93.05 mM). Among the VFAs, the molar proportion of acetate was higher (p<0.01) in BCFA supplemented group (71.07 mM) as compared to control (64.98 mM). However, the concentration of propionate and butyrate remained unchanged. Amino acids composition of bacterial hydrolysates was similar in both the groups. Ruminal outflow rate of liquid digesta was higher (p<0.01) in BCFA fed group ($67.56l\;day^{-1}$) than control ($52.73l\;day^{-1}$). It is concluded that the dietary supplementation of Na-salt of isobutyric acid in low protein diet improved the nutrient utilization and ruminal fermentation characteristics.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.4
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• pp.534-541
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• 2009

The aim of this study was to evaluate the effects of gamma irradiation (${\gamma}$-irradiation) at doses of 15, 30 and 45 kGy on chemical composition, anti-nutritional factors, ruminal dry matter (DM) and crude protein (CP) degradibility, in vitro CP digestibility and to monitor the fate of true proteins of full-fat soybean (SB) in the rumen. Nylon bags of untreated or ${\gamma}$-irradiated SB were suspended in the rumens of three ruminally-fistulated bulls for up to 48 h and resulting data were fitted to a nonlinear degradation model to calculate degradation parameters of DM and CP. Proteins of untreated and treated SB bag residues were fractionated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Digestibility of rumen undegraded CP was estimated using the three-step in vitro procedure. The chemical composition of raw and irradiated soybeans was similar. Results showed that phytic acid in ${\gamma}$-irradiated SB at dose of 30 kGy was eliminated completely. The trypsin inhibitor activity of 15, 30 and 45 kGy ${\gamma}$-irradiated SB was decreased (p<0.01) by 18.4, 55.5 and 63.5%, respectively. From in sacco results, ${\gamma}$-irradiation decreased (p<0.05) the washout fractions of DM and CP at doses of 30 and 45 kGy, but increased (p<0.05) the potentially degradable fractions. Gamma irradiation at doses of 15, 30 and 45 kGy decreased (p<0.05) effective degradability of CP at a rumen outflow rate of 0.05 $h^{-1}$ by 4.4, 14.4 and 26.5%, respectively. On the contrary, digestibility of ruminally undegraded CP of irradiated SB at doses of 30 and 45 kGy was improved (p<0.05) by 12 and 28%, respectively. Electrophoretic analysis of untreated soybean proteins incubated in the rumen revealed that ${\beta}$-conglycinin subunits had disappeared at 2 h of incubation time, whereas the subunits of glycinin were more resistant to degradation until 16 h of incubation. From the SDS-PAGE patterns, acidic subunits of 15, 30 and 45 kGy ${\gamma}$-irradiated SB disappeared after 8, 8 and 16 h of incubation, respectively, while the basic subunits of glycinin were not degraded completely until 24, 48 and 48 h of incubation, respectively. It was concluded that ${\gamma}$-irradiated soybean proteins at doses higher than 15 kGy could be effectively protected from ruminal degradation.

• Economic and Environmental Geology
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• v.43 no.2
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• pp.149-162
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• 2010

The most serious problem in oil stockpiles with artificial underground cavern is maintaining the stability of ground water system. In order to understand the ground water system around K-1 site, we determined the regional flow direction and level distribution of groundwater, and investigated the major geologic factors influencing their flow system. Reactivated surface along the contact between granite and gneiss, and fractures and faults along the long acidic dyke may contribute as important pathways for groundwater flow. Within K-1 site, groundwater level fluctuation is closely related to the rainfall events and injection from surface or influx water. In this project, the effect of groundwater pumping from the southern wells was examined. Based on equations relating water level drawdown to pumping rate at those wells, their pumped outflow of groundwater ranged from $80\;m^3$/day to less than $250\;m^3$/day. The modeling results with MODFLOW imply that the previous groundwater pumping at distance of 1.2 km may not affect the groundwater level variations of the K-1 site. However, continuous pumping work at quantity over $250\;m^3$/day in this area will be able to affect the groundwater system of the K-1 site, particularly along the acidic dyke.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2000.11a
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• pp.81-87
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• 2000

Beat-to-beat changes in heart period (heart period variability, HPV) are mediated by fluctuations in autonomic activity. Spectral analysis is used to quantify such fluctuations in the range of 0.15-0.40 Hz (high frequency, HF), which are influenced primarily by parasympathetic factors. These fluctuations are often referred to as RSA (respiratory sinus arrhythmia), the physiological phenomenon extracted by spectral analysis and other methods including histograms of heart rate ( HR), deviations of HR etc. Respiratory sinus arrhythmia indexing with peak-to-valley method suggested by Grossman et at., (1981) yields a simple range statistic and is quantified on breath-by-breath basis, thus being quite sensitive and less dependent on recording time as compared to spectral analysis. It is strongly recommended to use at least 1 min epoch to asses HF component of HPV and at least 2 min fer low frequency (LF) of HPV and even 5 min far valid clinical assessment. Peak-to-valley statistic is limited to RSA index only, but has its pragmatic advantages. Most important is possibility of its application far relatively small epoch analysis. We used short periods (20,30, 40 sec only) and off-line analysis of RSA using ECG and respiration curve this method of assessment and proved that this method is more practically effective. The RSA index was not so far dependent on respiration pattern differences and reflected actual vagal control of HR and were accompanied by low HR under some high stress conditions and in an aversive affective visual stimulation experiments. Another factor that might modulate cardiac chronotropic response is the interaction of sympathetic and parasympathetic inputs on sino-atrial (SA) node level, because responses to vagal influences are known to be proportional to ongoing sympathetic activity, that is so called accentuated antagonism. Since sympathetic outflow (increment of influences on SA) under negative emotions or stress was high in almost all physiological responses, vagal effects on HR could be therefore potentiated, leading to masking of output cardiac response seen in HPV, In the case of moderate sympathetic activation, on the other hand, autonomic interactions in cardiac control appear to be minimal. Thus RSA index appears to be an effective alternative method to assess and measure spectral HPV.