• Journal of Korean Society of Water and Wastewater
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• v.25 no.5
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• pp.667-679
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• 2011

In this study, the influences of pollutant from Dae-po Stream and So-gam Stream located at the downstream of Nak-dong River on the water quality at Mul-geum water intake station were analyzed using RAMS model. Field measurements of velocity by ADCP, and water quality distribution of BOD and TP by water sampling were carried out to present the input and verification data for numerical simulations. The comparison between RAM2 and ADCP measurement, which aimed for the analysis of 2-D velocity distribution around Mul-geum water intake station showed that two results matched well along the spanwise direction. The prediction of pollutant concentration by RAM4 agreed fairly well with the measured data except for the points nearby right banks in the vicinity of tributary pollutant source. Flushing effect by the increase of mainstream discharge in Nak-dong River was analyzed to provide the damage mitigation in preparation for the accidental water pollution. With increasing mainstream discharge, high velocity and increased water quantity induced increasing dilution effect, thereby decreasing the inflow pollutant concentration rapidly.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.1
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• pp.91-101
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• 2003

Boryeong Seadike located at southwestern seashore of Korean peninsula completed in 1997. Sluice gate operation can be an important factor to maintain lake water quality and reduce retaining time of pollutants within lake. The lake water quality simulation model, WASPS was adopted and tested to find out proper gate operation timing and discharge amount. From the simulation of sluice gate operation, the results showed that the later the time of discharge for loosing 1 day successively to 6 days, the better the quality of water. Discharge amount showed relatively minor changes of water quality. This means that pollutants flowed into lake from watershed do not have enough time to mix up with deep water when the gate opened at early time. About 3 days delay of discharge caused the dilution effect to stabilize the lake water quality in case of Boryeong freshwater lake.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.2
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• pp.171-178
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• 2008

Galileo is the Europe's global navigation satellite system corresponding to the GPS. The GIOVE-A test experiment has been finished and the second test satellite GIOVE-B will be launched soon. The integration of GPS and Galileo lead an increase of visible satellite number. We can obtain an improved navigation performance in signal blocked area such as urban or forest. GPS and Galileo have each time-coordinate system and use the different error model to calculate the navigation solution. In this paper, we studied on GPS and Galileo channel error model and time-coordinate system. Using this result, we implement the integrated navigation algorithm. In simulation, we analyzed the navigation error caused by time and coordinate disagreement and verified performance of integrated navigation algorithm in terms of visible satellite number, DOP(Dilution of Pression) and position error.

• Korean Journal of Veterinary Research
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• v.36 no.1
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• pp.65-74
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• 1996

Atrial Natriuretic Peptide(ANP) is a hormone with potent natriuretic, diuretic and relaxing properties of vascular smooth muscle. Specific chemical modulator responsible for the ANP secretion has not yet been found. Although atrial stretch of stretch-release is to be a major stimulus for the secretion of ANP, the precise mechano-molecular transduction mechanism responsible for its evoked secretion remains to be elucidated. It is interested to clarify the effect of superoxide anion in the stretch-induced ANP secretion. In order to investigate the effectg of $H_2O_2$ in the regulation of ANP secretion, a perfused model of left atrium of rats was used. The results obtained were as follows; 1. The ANP secretion and the extracellular fluid(ECF) translocation were accentuated by the effect of repetitive atrial distension-reduction volume at atrial pressure($4cmH_2O$). 2. The dilution curve showed to be in parallel between pure atriopeptin III (AP III) and perfusated buffer. 3. $H_2O_2(5{\times}10^{-4}M)$ accenturated a strectch-release induced increase of the ANP secretion. The amount of released ANP was significantly(p<0.01) increased. These results suggest that the superoxide anion may be involved in the regulatory mechanism of mechanically activated ANP release.

• Bulletin of the Korean Chemical Society
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• v.6 no.3
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• pp.128-131
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• 1985

A series of copolymer membranes of 2-hydroxyethylmethacrylate (HEMA) with selected hydrophobic monomers were prepared without crosslinking agents. The equilibrium water content, the partition coefficient, and the permeability of the solutes such as urea, methylurea, 1,3-di-methylurea, and acetamide via these membranes were measured. The partition coefficient data show that as the hydrophobicity of solutes increased, the partition of solutes were dictated by hydrophobic interaction between solute and polymer matrix. Diffusion coefficients obtained in these experiments decrease as the water content of polymer membrane decreases. This decrease is blunt as the excess heat capacities, ${\phi}C^0_p$ (excess) in aqueous solution at infinite dilution of solute increases. To investigate the relationship between water content and diffusion coefficient, the results of the diffusion experiments were examined in light of a free-volume model of diffusive transport. The remarkable increase of urea mobility in the polymer network containing relatively larger bulk water can be considered as water structure breaking effect.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.6
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• pp.466-473
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• 2011

The buoyancy and initial momentum fluxes make near-field dominated by buoyant jet when thermal discharge releases underwater. In order to estimate prediction capabilities of those near-field phenomena, non-hydrostatic RANS applied CFD(Computational Fluid Dynamic) model was used. Condition of model was composed based on past laboratory experiments. Numerical simulations carried out for the horizontal buoyant jet in the stagnant flow and vertical buoyant jet into crossflow. The results of simulation are compared with the terms of trajectory and dilution rate of laboratory experiments and analytic model(CorJET) results. CFD model showed a good agreement with them. CFD model can be appropriate for assessment of submerged thermal discharge effect because CFD model can resolve the limitations of near-field analytic model and far-field quasi 3D hydrodynamic model. The accuracy and capability of the CFD model is reviewed in this study. If the computational efficiency get improved, CFD model can be widely applied for simulation of transport and diffusion of submerged thermal discharge.

• Korean Journal of Agricultural Science
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• v.43 no.4
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• pp.595-602
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• 2016

In pigs, individuals in the same pen may show aggressive behavior toward each other, such as tail biting. Such social interactions among pen mates may considerably affect their welfare and performance, both in negative and positive ways. The present study was conducted to investigate social genetic effects on days to 90 kg using data from 12,208 Duroc and Yorkshire pigs that were born between 2008 and 2012. Heritability was estimated using the five following animal models: a basic model with direct heritable effects only (Model 1), a social model with direct and social heritable effects (Model 2), a model accounting for covariance between direct and social heritable effects (Model 3), and two models considering a dilution factor with direct and social heritable effects (Models 4 and 5). The optimal model to represent Duroc pigs was Model 1 which only uses direct heritable effects. Direct heritability (0.21) was higher than total heritability (0.09) and covariance was negative. Model 2 was evaluated as the optimum model for Yorkshire pigs. Yorkshire data showed that total heritability (0.5) was twice as high as direct heritability (0.25) and covariance was positive. Our results suggest that the efficiency of social effects differed among breeding lines. Further research on social effects related to breeds by group size would clarify which is the most efficient selection method that accounts for social genetic effects.

• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.3
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• pp.198-207
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• 2012

In this study, we investigated the effect of ocean fertilization by deep sea water, using an ecosystem model which contains not only phytoplankton but also zooplankton. The model is based on NEMURO which consists of eleven compartments - two species of phytoplankton, three species of zooplankton, $NO_3$, $NH_4$, $Si(OH)_4$, particulate organic nitrogen, dissolved organic nitrogen and particulate silicon. We introduced nitrogen cell quota in the both species of phytoplankton, and silicon cell quota in the large phytoplankton in addition to the eleven compartments of NEMURO. We made the experiment at Izu Oshima Island in order to investigate the effect of ocean fertilization. In this experiment, we could not find clear differences between the cases with and without deep sea water. We investigated the causes of the experiment results by the model simulations. One of the causes was high concentrations of nutrients in surface seawater used in the experiment. Another was that the increase of total concentration of inorganic nitrogen does not necessarily accelerate the photosynthetic rate because inorganic nitrogen uptake rate is related to the ratio of $NO_3$ to $NH_4$. Because the model can represent the results of the experiment, we investigated the effect of ocean fertilization by deep sea water using this model. We found that the effect of ocean fertilization hardly appeared when the interval of the addition of deep sea water was too short, or the amount of deep sea water was too much. It is supposed that if the addition of deep sea water is too frequent or too much, the dilution of plankton's concentrations will exceed the effect of promoting phytoplankton's photosynthesis.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.21 no.3
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• pp.230-240
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• 2009

The ESCORT model is applied at Mokpo coastal zone to analyze the effect of fresh water discharge released from the gates of the Youngsan River sea-dyke. Applicability and validity of both 2-D and 3-D hydrodynamic modules could be guaranteed by simulating hydrodynamic feature with ebb dominance characteristics. Then, effects of the released discharge on the hydrodynamics are investigated. And analysis of the effects on diffusion phenomena show that 3-D model is essential for such diffusion modelling. Moreover, vertical salinity distributions near the gates are examined, and the influence range of fresh water is also estimated, which shows that dilution of fresh water is going on slowly because of poor flushing.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2007.04a
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• pp.147-153
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• 2007

Central to developing new treatment strategies for late onset sporadic Parkinson's disease (PD) and early onset familial PD is resolving the enigma of the specific vulnerability exhibited by substantia nigra dopamine (DA) neurons despite multiple risk factors. Neuropathological evidence from both human and experimental models of PD firmly supports a significant role for oxidative stress (OS) and mitochondrial dysfunction in the death of nigral DA neurons. Largely unknown are the genes underlying selective susceptibility of nigral DA neuron to OS and mitochondrial dysfunction and how they effect nigral DA cell death. To overcome the paucity of nigral DA neurons as well as the dilution effect of non-DA cells in brain tissues, we have developed wild type DA cell line model, SN4741 and mutant DJ-1 (-/-) DA cells, appropriate for microarray analysis and differential mitochondrial proteomics. Mutations in the DJ-1 gene (PARK7), localized in cytoplasm and mitochondria, cause autosomal recessive early onset PD. Through microarray analysis using SN4741 cells followed by validation tests, we have identified a novel phylogenically conserved neuroprotective gene, Oxi-a, which is specifically expressed in DA neurons. The knockdown of the gene dramatically increased vulnerability to as. Importantly as down-regulated the expression level of the gene and recovery of its expression via transient transfection exerted significant neuroprotection against as insult. We also have identified altered expression of mitochondrial proteins and other familial PD genes in DJ-1 (-/-) mutant cells by differential mitochondrial proteomics. In DJ-1 (-/-) cells the knockdown of the other familial PD genes (Parkin and PINK1) dramatically increased susceptibility to as. Thus, further functional characterization of the Oxi-$\alpha$ gene family and the mitochondrial alteration in the DJ-1 (-/-) cell model will provide the rationale for the neuroprotective therapy against both sporadic and familial PD.