• Journal of Korean Society on Water Environment
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• v.39 no.6
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• pp.439-450
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• 2023

The Yeongsan River, a major water resource for Jeollanam-do, that is adjacent to industrial complexes and agricultural areas, is exposed to water pollution. Therefore, it is necessary to investigate the impact of water pollution incidences and prepare response systems for river environment safety for other water resources in the future. Environmental Fluid Dynamics Code (EFDC) was applied to the mainstream of the Yeongsan River where residential, commercial, and agricultural areas are located to analyze the behavior of pollutants conducting the scenario analysis. Considering the pollutants that affected the study area, two pollutants, oil and benzene, with different physical and chemical characteristics were selected for the analysis. As a result of comparing the actual and simulated values of the water elevation, temperature, and flow rate, it was confirmed that the model adequately reproduced the hydraulic characteristics of the Yeongsan River. The oil flow dynamics showed that an increase in flow rate led to reduction in the maximum height of the slick. Notably, the behavior of the oil was predominantly influenced by the wind conditions. In the case of benzene, lower flow scenarios exhibited decreased arrival times and residence times accompanied by an elevation in the maximum concentration levels. From the results of pollutant behavior in the study area, it is feasible to utilize the section of tributary confluence for collection and the weir area for dilution. This study enhances the understanding of the pollutant's behavior with different characteristics and develops effective control systems tailored to the physicochemical attributes of pollutants.

• The Korean Journal of Mycology
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• v.11 no.2
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• pp.79-84
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• 1983

To study physiological and ecological characters of the secondary mycelia of Armillariella mellea, it was cultivated on the various media. It was grown very well on the malt extract medium compared with its growth on yeast extract medium, potato dextrose medium and Hamada medium. The temperature of $27^{\circ}C$ gave the best condition for it to grow. The highest rate of growth was shown in medium of pH 6. Heteroauxin of 5 ppm concentration showed a increase as 26.2% in growth in compared with the control group. Gibberelline 10ppm, Tomatoton of 10,000 dilution and Adoton of 5,000 dilution showed positive effect. It was shown that the use of above hormones in appropriate concentration brought the effect of growth, but overuse of them brought inhibitory effect. Under the same condition of 200ppm concentration, vitamin A gave the highest growth of 18.2% than that of the control used.

• Transactions of the Korean hydrogen and new energy society
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• v.35 no.3
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• pp.324-335
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• 2024

The container package type sealed water electrolysis production system installs mechanical balance of plant and electrical balance of plant as an integrated unit to enable independent operation within the package module. The auxiliary equipment required to operate the water electrolysis system must be integrated to reduce the installation area and shorten the installation time. At this time, as leak risk factors are placed in a dense space, when a hydrogen gas leak accident occurs, it can have a mutual influence on other adjacent facilities, so it contains various risk factors. In this study, when a gas leak occurs in a container packaged water electrolysis system, possible sources of leakage in the system according to the KS C IEC 60079-10-1:2015 and KGS GC101 standards were identified, and the leak rate and leak characteristics were calculated. did. The hazardous area and its range were calculated according to ventilation and dilution characteristics. In order to optimize ventilation characteristics, design of experiment was used to analyze the influence to evaluate the adequacy of ventilation, and overseas ventilation standards were analyzed and compared. In addition, the optimal ventilation structure and characteristics of the container packaged water electrolysis system were presented according to the results of the experimental design method.

• Journal of Life Science
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• v.21 no.8
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• pp.1156-1162
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• 2011

Equine coital exanthema caused by equine herpesvirus type 3 (EHV-3) is a venereal disease which seriously drops horse reproduction rates. Here, we isolated EHV-3 from infected horses and investigated their biological characteristics. Initial cytopathic effects such as rounding of cells were detected 48 hours post infection of the virus into RK-13 cells. The infected cells were going to detach from the surface of culture flasks 72 hours post infection. The type of isolated viruses from swabbed samples was EHV-3 by PCR analysis. Glycoprotein G (gG) of isolated EHV-3 has a 99.25 percent similarity rate to that of EHV-3 334/74 control strain. The isolated EHV-3 was named Georo strain. Georo strain consisted of four major proteins including 145 kD, 60 kD, 45 kD and 40 kD, as shown by SDS-PAGE analysis. We hope the newly isolated Georo strain of EHV-3 can be used for studying various aspects of Korean equine coital exanthema.

• Microbiology and Biotechnology Letters
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• v.8 no.1
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• pp.55-60
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• 1980

Some of the cultural conditions were improved in order to obtain the higher biomass of Lactobacillus bulgaricus NLS-4 which has the higher lactic acid producing activity as well. Among eight media including 11％ non-fat milk medium as a control, the TIP medium was selected. By a batch experiment, the maximum cell concentration could be increased to 1.0$\times$10$^{9}$ cells per $m\ell$ when the organism was grown at 38$^{\circ}C$ for 18 hours with agitation speea of 200 rpm and under the constant level of pH 6.5 con-trolled with 1 N KOH solution in the selected medium. The cell concentration was further increased to 2.3$\times$10$^{9}$ cells per me in the steady state of continuous culture at the dilution rate of 0.17 hr$^{-1}$ for 18 hours.

• Korean Journal of Environmental Agriculture
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• v.20 no.3
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• pp.186-191
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• 2001

Recently, petroleum spray oil(PSO) has been used to control key pests in integrated pest management (IPM) of citrus and other orchards in Australia and USA. In order to clarify the influences of a newly developed PSO (D-C Tron $Plus^{(R)}$) on citrus leaves, 0.33% or 1.0% of PSO were sprayed to potted 4-year-old citrus trees under some kinds of condition, and then the changes of photosynthesis, transpiration, stomatal conductance and chlorophyll fluorescence(Fv/Fm) were determined. When sprayed with 1.0% PSO, the photosynthetic rate, transpiration and stomatal conductance of citrus leaves were decreased by 20%, and then recovered in 20 days after treatment (DAT), while there were little influences by the spray of 0.33% PSO. The value of Fv/Fm decreased more under the $34/24^{\circ}C$ temperature condition than that of under the $30/20^{\circ}C$ and $28/16^{\circ}C$ condition. The high temperature ($50^{\circ}C$ for 10 hours)-treated trees sprayed with PSO 1.0% or PSO 1.0% plus dithianon 1/2000 dilution showed not only the increase of rate in dropped leaf but also the reduced photosynthesis and Fv/Fm compared with $30/20^{\circ}C$ temperature-treated ones. From the results of this study, the spray of 1.0% PSO can inhibit the physiological activities in citrus leaf, particularly under high temperature condition after spray or the mixing-spray with a fungicide (dithianon WP, 75%).

• Journal of Korean Society of Forest Science
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• v.107 no.1
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• pp.71-80
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• 2018

The effect of $SO_2$ treated pads (Sodium metabisulphate 0, 0.5, 1.0, 2.0 g/kg) on the quality of dried persimmons and dried persimmons slices were investigated. The $SO_2$ treated pads did not affect to weight, moisture loss rate, and soluble solid contents of dried persimmons and dried persimmons slices. The color change (${\Delta}E$) of dried persimmons and dried persimmons slices after storage for 8 weeks were the highest (value=6.0, 6.2) in control, whereas that was the lowest (value=4.8, 4.7) under $SO_2$ pad 2.0 g/kg condition, respectively. When we measured the browning degree of dried persimmons, they showed O.D. 0.65, 0.57, 0.29, and 0.18 in serial dilution treated pads with $SO_2$ pad 0, 0.5, 1.0, and 2.0 g/kg. The browning degree data from aforementioned dried persimmons after 8 weeks was similar to that from dried persimmons slices. The decay rate of dried persimmons and dried persimmons slices after storage for 8 weeks were the highest (value=33.3%, 36.7%) in control, whereas that was the lowest (value=3.3%, 6.7%) under $SO_2$ pad 2.0 g/kg condition, respectively. The concentration of residual $SO_2$ in dried persimmons and dried persimmons slices were detected within a safe range of 15.3~30.0 ppm. Therefore, the shelf-life of dried persimmons and dried persimmons slices were lengthened in $SO_2$ treated pads (especially in $SO_2$ pad 2.0 g/kg) for inhibiting of browning and decay.

• Korean Journal of Poultry Science
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• v.40 no.1
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• pp.11-16
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• 2013

Salmonella is closely related with human health of modern society which has concern increased in livestock goods consumption as well as give economic damage throughout the chicken industry such as farm, hatchery, slaughter house and processing plant. From 2007 to 2011, this study investigated Salmonella prevalence from 200 old hen delivery trucks which deliver old egg-laying hens and broiler breeders in Korea. The prevalence of Salmonella species was 38.0% in old hen delivery truck. Serogroup C1 was the most frequently detected serogroup of Salmonella, followed by the serogroups D1, C2 and B. A total of 25 serotypes were identified and Salmonella infantis was the most frequently isolated serotype. In addition, we applied disinfectant to old hen delivery truck for the reduction of Salmonella contamination. The disinfectant consists of formaldehyde, glutaladehyde and quaternary ammonium compound was applied to the trucks. Salmonella isolation rate was significantly decreased after disinfection from 38.0% to 7.5%. Disinfectant could not effectively reduce Salmonella contamination at a dilution of 1:200 which is recommended by manufacturer, but Salmonella isolation rate was significantly decreased at a dilution of 1:50. Since old hen delivery truck could be a potential vector to carry Salmonella into farms and abattoirs, chicken delivery truck should be disinfected thoroughly and sufficiently to control contamination of farms and abattoirs.

• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.298-304
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• 2010

Nutrient uptake by plants and drainage ratio in culture beds can affect ion balance and concentrations of nutrient solutions in electrical conductivity (EC)-based closed-loop soilless culture. This study was conducted to analyze ion concentration changes with time and drainage ratio under EC-based nutrient control in closed-loop soilless culture for sweet pepper plants (Capsicum annum L. 'Boogie'). At first experiment, ion concentrations of the nutrient solution were periodically analysed while collected drainage was being reused by mixing with fresh nutrient solution at a dilution rate of EC $2.2\;dSm^{-1}$. Changes in ion concentrations of $K^+$, $Ca^{2+}$, $Mg^{2+}$, $NO_3^-$, $SO_4^{2-}$, and $PO_4^{3-}$ were 1.13, 5.35, 0.92, 0.9, 1.10, $0.19\;meq{\cdot}L^{-1}$, respectively. Ion balance such as $K^+$ : $Ca^{2+}$ and $SO_4^{2-}$ : $NO_3^-$ were mainly affected during the recirculation of nutrient solution. At second experiment, ion concentrations and EC of drainage were compared before and after replenishment under different four drainage ratios of 7%, 16%, 39%, and 51%. Ion ratios of the recirculated nutrient solutions such as $K^+$ : $Ca^{2+}$ for cation and $SO_4^{2-}$ : $NO_3^-$ for anion were investigated. ECs of drainage decreased with increase of drainage ratio and each ion concentration showed the same trends as EC did. Ion balances in drainage with drainage ratio were a little different from each other, but each ratio could be corrected by replenishment process. The ion balance at 7% drainage ratio was closest to initial ratio and followed by 16%, 51%, and 39% in the order. Ion balance such as $K^+$ : $Ca^{2+}$ and $NO_3^-$ : $PO_4^{3-}$ were mainly affected the correction process.

• The Korean Journal of Physiology
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• v.24 no.1
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• pp.27-37
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• 1990

The extrafetal transfer of $Li^{+}$ in amniotic fluid was studied in 45 pregnant rabbits. LiCl solution was administered either intravenously to mother or directly into the amniotic sac and monitored the appearance and disappearance of $Li^{+}$ in the amniotic fluid, then calculated the transfer rate of $Li^{+}$ of extrafetal origin. To study the transplacental $Li^{+}$ transfer, a solution of 150 mM LiCl was infused continuously via maternal vein (initial dose: 0.7 mmol/kg, maintaining dose: 0.03 mmol/kg/min) and the $Li^{+}$ concentration was measured in maternal blood and amniotic fluid after 60 and 120 minutes of infusion. Change in the volume of aminotic fluid was determined by Congo red dilution method at the same time. Effects of duration of gestation was not considered in this study. Extrafetal transport of $Li^{+}$ into the amniotic fluid was estimated by comparing the $Li^{+}$ concentration and volume of amniotic fluid determined before and after ligating the placental vessels. Extrafetal $Li^{+}$ transport from the amniotic fluid was determined by observing the time dependent disappearance of $Li^{+}$ and Congo red in amniotic fluid after injecting 0.5 ml solution of 15 mM or 90 mM LiCl and 50 mg/ml Congo red. Following are the results obtained: 1) During infusion of LiCl through maternal vein the ratio of the aminotic $Li^{+}$/maternal plasma $Li^{+}$ increased significantly along with the increment of fetal weight. 2) The volume of amniotic fluid of larger fetuses than 20.5 gm increased significantly during administration of LiCl while that of smaller fetuses did not change. 3) After umbilical cord ligation the $Li^{+}$ concentration of amniotic fluid of larger fetuses than 20.5 gm was decreased to $59.9{\pm}10.3%$ and $56.9{\pm}42.9%$ $(mean{\pm}S.D.)$ of those of control group after 60 and 120 minutes of LiCl infusion respectively. In amniotic fluid of smaller fetuses than 20.5 gm, there was no significant difference between control and ligation groups. 4) The disappearance rate of Congo red in the amniotic fluid was $45.2{\pm}8.2%/hr$. 5) The disappearance rate of $Li^{+}$ after intraamniotic injection of LiCl depended on the amount injected. On injecting $7.5\;{\mu}mol$ LiCl, $Li^{+}$ disappeared rapidly from the amniotic fluid and the rates after 60 min and 90 min were $97.0{\pm}2.8,\;98.5{\pm}2.0%$ respectively. On injecting $45\;{\mu}mol$ LiCl, the rates were $56.0{\pm}15.4,\;78.9{\pm}14.5%$ at 60 and 90 min. 6) From the above results it was concluded: a) $Li^{+}$ transfer into the amniotic fluid increased along with the fetal growth and one half of $Li^{+}$ influx is through the extrafetal route even after the maturation of fetal kidney. b) One half of the $Li^{+}$ transfer from the amniotic fluid was through swallowing of fetus, while the remaining half was transfered rapidly through amniotic membrane, which was concentration limited.