• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.2
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• pp.76-93
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• 2013

The hydrodynamics in the Youngsan River Estuary has changed due to coastal developments such as the estuary dam and two tidal barriers. As the freshwater discharge is artificially controlled, the circulation pattern is different from those of natural estuaries and the river-born sediment supply is restricted. 3D numerical modeling system EFDC was applied to investigate the sediment transport pattern and budget in summer with river floods. The real-time driving forces and the fluvial sediment discharges from the watershed modeling were assigned for the simulation period. The size classes of sand, silt and clay were adopted based on the grain-size distribution of bottom sediments. The modeling results were calibrated and validated with the observed tides, tidal currents and suspended sediment concentrations. The suspended sediments are transported to the offshore at surface layer, whereas upstream toward the dam at mid- and bottom layers in August 2011. The characteristic estuarine circulation induced by the freshwater discharge from the dam, causes the deposition of silt-sized sediments on the whole and the sustained suspension of clay-sized sediments.

• Korean Journal of Ecology and Environment
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• v.43 no.3
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• pp.349-355
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• 2010

This study aims at the augmentation of reliability of the long-term rainfall runoff model. To do so agricultural water uses are evaluated by analyzing the effects of small scale irrigational hydraulic structures on long term runoff processes and thereby rainfall-runoff model is modified considering them. As a result the simulation results of the sub-basins having more agricultural reservoirs than the others are disagreed with the observations. The 2nd quarter simulation results show similar trend to it. Especially the farming seasonal results of the drought year as the year of 2008 have many negative discharge values due to the lack of agricultural water uses. This result come from the water uses input data corresponding to not real water uses but water demands. In this study the formulas are derived to estimate the discharges and return ratios and the long term rainfall-runoff model is reformulated based on these. It is confirmed that the errors of the simulation results could be reduced by considering the effects of small scale irrigational hydraulic structures and the reliability of the simulation results improved greatly.

• Journal of Embryo Transfer
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• v.25 no.1
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• pp.77-84
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• 2010

This study was carried out the normal serial ultrasonographic appearance of the postpartum uterine involution with small pet bitches. Postpartum changes in uterine shape, architecture, echogenicity and diameter were monitored with ultrasonography in small pet bitches (Miniature Schnauzer, Cocker Spaniel and Shih-tzu). In the Miniature Schnauzer bitches, uterine diameter of the placental sites and interplacental sites were decreased from $24.31{\pm}1.65\;mm$ at 1 day to $13.56{\pm}0.76\;mm$at 7 day, and $15.19{\pm}1.28\;mm$ at 1 day to $10.41{\pm}0.76\;mm$ at 7 day postpartum. In the Cocker Spaniel, the placental sites and interplacental sites were decreased from $24.90{\pm}1.62\;mm$ at 1 day to $14.14{\pm}1.21\;mm$at 7 day, and $15.33{\pm}1.47\;mm$ at 1 day to $10.19{\pm}0.83\;mm$ at 7 day postpartum. In the Shih-tzu, the placental sites and interplacental sites were decreased from $23.96{\pm}1.55\;mm$at 1 day to $13.84{\pm}0.94\;mm$ at 7 day, and $14.93{\pm}1.29\;mm$ at 1 day to $9.98{\pm}0.84\;mm$ at 7 day postpartum. And uterine diameter was no statistically significant difference among bitches (p>0.05). At 67 days, the uterine diameter in Miniature Schnauzer bitches were 6~7 mm both placental and interplacental sites, and the uterine horns showed uniform hypoechoic, tubular structures without enlargement. In present study, the involution of the uterus was completed at 67 days after parturition in Miniature Schnauzer, and 65 days in Cocker Spaniel and the Shih-tzu. There were no significant differences of normal postpartum uterine involution between small pet bitches (p>0.05). In conclusion, the postpartum involution of small pet bitches appeared to be completed normally at 65~67 days after parturition and could be identified by gross findings such as vaginal discharges and ultrasonographic findings of uterine shape and echogenicity.

• Journal of Veterinary Clinics
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• v.25 no.3
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• pp.159-164
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• 2008

This study was carried out to determine the therapeutic effect of injection-acupuncture (AP) with bee-venom (apitoxin) in cases of canine otitis externa (COE). Fifteen dogs with naturally-acquired otitis externa were used in this study. The dogs were divided into the following antibiotics group (control group), apitoxin group (experimental group A) and apitoxin combined with antibiotics group (experimental group B). All groups were treated by ear cleaning with normal saline once on day 1. The control group was treated with susceptible antibiotics, and experimental group A was given injection-AP with apitoxin $(100{\mu}g/head)$ at TH17 (Yi Feng), SI19 (Ting Gong), GB03 (Shang Guan) and TH03 (Zhong Zhu) bilaterally. Experimental group B was treated with susceptible antibiotics and injection-AP with apitoxin at the same acupoints as experimental group A. All the groups were treated 3 times/week for 2 weeks. The identity of the causative agents, the changes in the clinical signs, otoscopic findings, bacterial count in the auricular discharges, and total WBC counts and neutrophil/lymphocyte (N/L) ratio in the peripheral blood were investigated in all groups. In bacterial isolation, Staphylococcus spp. combined with Streptococcus spp. was detected higher than other agents. The bacterial cell count in experimental group A was significantly decreased at 2 weeks (p<0.01), and those in experimental group B was significantly decreased at 1 week (p<0.01) and 2 weeks (p<0.01) compared by those of control group, respectively. The changes of clinical score in experimental group B were significantly decreased at 2 weeks (p<0.01) compared by those of control group, but, those of experimental group A was similar to those of control group. The changes of total WBC counts and neutrophil/lymphocyte (N/L) ratio were no significant difference found. In conclusion, injection-AP with apitoxin is an effective treatment for COE and might be an alternative method for treating COE.

• Journal of Korea Water Resources Association
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• v.43 no.6
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• pp.543-557
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• 2010

The effects of the selection for sediment transport equations and advection-diffusion equations according to different sediment transport modes on the modeling results of bed changes were analyzed using the CCHE2D and compared with field data in this paper. The most suitable sediment transport equation and sediment transport mode for advection-diffusion equation were suggested for the upstream approached channel of the Nakdong River Estuary Barrage. The bed changes simulated by the Engelund and Hansen formula were very small in the modeling case for the low and high flow discharges compared with the case of the Ackers and White formula. Also, the numerical modeling with the actual hydraulic event in 2002 presents that the bed change result with the bed load transport type for advection-diffusion equation was close to the field measurement more than the suspended load type.

• Journal of Korea Water Resources Association
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• v.49 no.12
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• pp.1035-1044
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• 2016

In joint portions of the levee and the barrier, complex 3-dimensional flow was generated and collapse of revetment occurred frequently. For these reasons, it is necessary to install the joint revetment with greater stability as compared with the general revetment at the joint portions. However, design criteria for joint revetment was not presented in River Design Criteria (KWRA, 2009). Therefore it is necessary to research for engineering design of the joint revetment. In this study, hydraulic experiments were performed under various flow conditions in order to realize the collapse conditions of riprap and carried out in 20.0 m straight open channel with one side levee and the width was 4.0 m. The diameter of riprap covered around joint revetment was 0.03 m and the inlet discharges were $0.5{\sim}0.8m^3/s$. The numerical simulations were performed under same conditions with experiment. as results of this numerical simulations, the influence range was confirmed from the distribution of flow characteristics and shear stress. As a result, the riprap diameter of the joint revetment was calculated from 4.1 to 6.9 times greater than that of general revetment. As the inlet discharge was large, the range of vulnerable area was developed long in the downstream direction despite of same withdrawal velocity of riprap. Through this study, the methods of calculating the riprap diameter and influence range were proposed according to hydraulic characteristics of flow around joint revetment. At a later study, if additional experiments about effect of flood plane and various types of barrier is applied, it is expected that rational design method with stability of joint revetment can be proposed.

• Current Research on Agriculture and Life Sciences
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• v.7
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• pp.55-66
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• 1989

The purpose of this study is to estimate the flood discharge and peak time by the SCS method and the probability method using the geomorpologic parameters obtained from the topographic maps following the law of stream classifying and, ordering by Horton and Strahler. The SCS method and the probability method are used in estimating the times to peak and the flood discharges at An-dong, Im-ha, and Sun-san basins in the Nakdong River system. The results obtained are as follows : 1. The range of the values of the area ratio, the bifurcation ratio and the length ratio agree with those of natural streams presented by Horton and Strahler. 2. Comparisons of the probability method and observed values show that small relative errors of 0-7% of flood discharge, and 0-2hr, difference in time to peak respectivly. But the SCS method shows that large relative errors of 10-40% of flood discharge, and 0-4hr, difference in time to peak. 3. When the rainfall intensity is large, the error of flood discharge estimated by using the probability method is relativly small.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.18 no.1
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• pp.43-52
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• 2006

Numerical model tests are done in order to evaluate impact zone of low salinity water on outer region of the developing Saemankeum reservoir. Also saline mixing processes are investigated f3r the inner reservoir with consideration of Mankyoung and Donjin riverine flood discharges when sea water is passing freely through gate. In these analyses 2-d ADCIRC, 3-d TIDED3D and CE-QUAL-ICM models are used. Through models tests, it is found that inner reservoir mixing process caused by inflow of outer sea water occurs gradually. It takes at least one month for complete mixing on Mankyoung part and 6 month on Dongjin part of the reservoir. When Sinsi or Garyeok gates are opened to control inner reservoir level, discharging velocities decrease exponentially from the gates, but show very strong currents of 0.5m/sec to the 10Km region apart. These results imply that hydrodynamic circulation and ecosystem of frontal region of the Saemankeum dike might be affected in amount by gate operations, since low saline inner waters are discharged periodically at ebb tide according to tidal level.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.5
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• pp.491-499
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• 2008

It is really urgent to develop wastewater treatment system which is economically efficient, occupies small area for buildup, can be easily operated, discharges small amount of sludge due to the more strict water quality standard, the expensive water and energy cost and so on. This study on treatment of wastewater including nonbiodegadable materials using white-rot fungus biofilm were designed to investigate the submerged type of biofilm, hydraulic retention times, recycle rates, and module turning times. Removal efficiencies of fully exposed biofilm type in atmosphere are similar to submerged biofilm of aeration type. The optimum conditions of white-rot fungus biofilm of fully exposed type in atmosphere are HRT 3$\sim$4 hr, recycle rate 6$\sim$10 Q, module turning times 0.5$\sim$2 times/min. At this time, removal efficiencies of organics were COD$_{Cr}$ 65.0$\sim$69.9%, NBDCOD 70.4$\sim$72.7%, BOD$_5$ 88.8$\sim$90.1%, SS 84.2$\sim$90.4%. Moreover average effluent concentration of BOD$_5$(8.9 mg/L) satisfied water quality standard of heavy water(BOD$_5$ less than 10 mg/L) but concentration of NBDCOD(29.6 mg/L) was higher than water quality standard of heavy water(NBDCOD less than 20 mg/L).

• The Korean Journal of Pain
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• v.19 no.1
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• pp.33-44
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• 2006

Background: Peripheral nerve injury leads to neuropathic pain, including mechanical hyperalgesia (MH). Nerve discharges produced by an injury to the primary afferents cause the release of glutamate from both central and peripheral terminals. While the role of centrally released glutamate in MH has been well studied, relatively little is known about its peripheral role. This study was carried out to determine if the peripherally conducting nerve impulses and peripheral glutamate receptors contribute to the generation of neuropathic pain. Methods: Rats that had previously received a left L5 dorsal rhizotomy were subjected to a spinal nerve lesion (SNL) or brief electrical stimulation (ES, 4 Hz pulses for 5 min) of the left L5 spinal nerve. The paw withdrawal threshold (PWT) to von Frey filaments was measured. The effects of an intraplantar (i.pl.) injection of a glutamate receptor (GluR) antagonist or agonist on the changes in the SNL- or ES-produced PWT was investigated. Results: SNL produced MH, as evidenced by decrease in the PWT, which lasted for more than 42 days. ES also produced MH lasting for 7 days. MK-801 (NMDAR antagonist), DL-AP3 (group-I mGluR antagonist), and APDC (group-II mGluR agonist) delayed the onset of MH when an i.pl. injection was given before SNL. The same application blocked the onset of ES-induced MH. NBQX (AMPA receptor antagonist) had no effect on either the SNL- or ES-induced onset of MH. When drugs were given after SNL or ES, MK-801 reversed the MH, whereas NBQX, DL-AP3, and APDC had no effect. Conclusions: Peripherally conducting impulses play an important role in the generation of neuropathic pain, which is mediated by the peripheral glutamate receptors.