• Korean Journal of Plant Resources
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• v.17 no.2
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• pp.75-81
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• 2004

This study was conducted to investigate effects of cryopreservation by vitrification on the seed germination rate and growth and physiological properties of seedlings of Maackia amurensis. Cryopreservation significantly decreased the germination rate of seeds of M. amurensis, but the reduction of germination rate was mitigated by the treatment of cryoprotectant (plant vitrification solution, PVS2) before plugging into liquid nitrogen and fast thawing rate after cryopreservation. Long-term PVS2 exposure decreased seed germination rate, whereas cryopreservation time didn't have influence on seed germination rate. In addition, growth and physiological properties of seedlings were not affected by PVS2 exposing time and cryopreservation time. Therefore cryopreservation could be widely used as a technique of long-term ex situ conservation without any damage and deterioration of cells or tissues of the forest seeds. However, in order to increase the effect of cryopreservation, we have to develope the lower toxic cryoprotectant and suitable techniques to the structural or chemical properties of a variety of seeds.

• Fire Science and Engineering
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• v.34 no.3
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• pp.8-17
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• 2020

In this study, the characteristics of HFIX insulated wire sheaths contaminated by pollutants were examined. KS C IEC 60811-1-3 standard was followed in performing the water-resistance wire tests. Pollutants were selected, and the specimens were exposed to the pollutants for a maximum duration of four weeks. The maximum tensile load and the elongation rate were measured each week. As the period of pollution exposure increased, the maximum tensile load of the specimens decreased by 6.22% and 6.52% at room temperature and high temperature, respectively, and 19.94% for specimens coated with a rust-proof lubricant. The elongation rate also decreased rapidly, such that the reductions in the properties of the sheath were significant. From the analysis of the surfaces using a scanning microscope, as the contamination period increased, structural changes such as perforation, split, and melting occurred, and the mechanical properties of the specimens decreased. Therefore, it is necessary to develop and follow an inspection cycle and periodically carry out repairs to prevent the deterioration of insulated wires.

• Journal of fish pathology
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• v.21 no.1
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• pp.57-66
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• 2008

Striped bitterling, Acheilognathus yamatsutae (TL: 4.25 ㎝, TW: 0.73 g)were exposed to 0.3, 1.3, 17.6 and 33.7 ㎍ L-1 (nominal concentrations) of nonylphenol (NP) for a period of 20 weeks. We studied on accumulation, growth and survival rate. After 20 weeks of exposure, the accumulation of NP in the body of the female and male was increased with increasing dose-dependent and female was higher than male. 4 weeks of exposure, TL of female striped bitterling was found to be increased in all of the dose group compared to control and 12 weeks of exposure, similar or some decreased in all of the dose group compared to control. 20 weeks of exposure, increased in all of the dose group compared to control and TL at 33.7 ㎍ NP L-1 were significantly higher than those in control (p <0.05). 4 weeks of exposure, TL and TW of male striped bitterling was found to be increased in all of the dose group compared to control and significantly higher in TL of 33.7 ㎍ NP L-1 (p <0.05). 12 and 20 weeks of exposure, TL and TW decreased in all of the dose group compared to control and significantly lower in 1.3 ㎍ NP L-1 of 12 weeks. Survival rate in both groups decreased with increasing NP concentration and there was a significant difference between control group and experimental groups exposed to each NP concentration.

• The Korean Journal of Malacology
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• v.29 no.2
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• pp.129-137
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• 2013

This study was conducted to find out the changes of survivorship, respiration and organ structure of Mactra veneriformis exposed to copper (Cu). Experimental period was four weeks. Experimental groups were composed of one control condition and three copper exposure conditions (0.025, 0.050 and 0.100 mg/L). The results of the study confirmed that copper induces reduction of survival rate and respiration rate and histopathology of organ structure of the bivalve. In the copper concentration of 0.100 mg/L, mortality was 100% after Cu exposure of 3 weeks. Respiration rate was observed exposure groups lower than control decline by 75%. Histological analysis of organ system illustrated expansion of hemolymph sinus, disappearance of epidermal layer and degeneration of connective tissue layer of the mantle. Also, histological degenerations as epithelial necrosis and hyperplasia of mucous cells are recognized in the gill and it was observed expansion of hemolymph sinus, disruption of epithelial layer, decrease of mucous cell and degeneration of connective tissue layer in the foot. In the digestive diverticulum, it was showed atrophy of basophilic cell and degeneration of epithelial cell in the digestive tubules, and as the concentration of copper increased the accumulation of lipofuscin increased.

• Korean Journal of Ichthyology
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• v.25 no.1
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• pp.1-8
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• 2013

Rockfish, Sebastes schlegeli (total length; $10.36{\pm}0.49cm$, total weight; $16.28{\pm}1.86g$, N; 290) were exposed to various concentrations of naphthalene for 28 days. Exposure concentrations of naphthalene established control, ethanol (solvent) control, 0.5, 1.0, 1.5 and 2.0 mg Nap $L^{-1}$. After exposure, We observed survival rate, and degree of tissue change (DTC) in gill under optical microscopy. Survival rate of the rockfish was more than 90% in control, ethanol control, 0.5 and 1.0 mg Nap $L^{-1}$, whereas it decreased in 1.5 and 2.0 mg Nap $L^{-1}$ (respectively 80%, 62.2%). In histological observation of gill, hyperplasia of epithelial cells observed in all exposure groups. But no showed increase of DTC which was related to concentration. Whereas, DTC at fusion of gill lamellar, lamellar telangiectasia, stasis, aneurysm and necrosis showed dose dependent increase. Especially, fusion of gill lamellar, lamellar telangiectasia and stasis observed at more 1.0 mg Nap $L^{-1}$, and aneurysm and necrosis at more 1.5 mg Nap $L^{-1}$. These results showed naphthalene caused survival and severe change to the gill of the rockfish which was related to exposure concentration.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.3
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• pp.310-320
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• 2008

Water temperature and salinity variation patterns were analysed using the CTD data measured in the Yeochari, Dongmakri and Donggeomdo intertidal zone, south of Ganghwado. Only the data during the submersion period of the measurement stations were used in this analysis. It is clearly shown that the correlation between air and water temperatures is very low and the water temperature variation shows clearly the opposite patterns as the tidal elevation increases and decreases. Whereas, the salinity change shows the similar pattern of the tidal elevation change pattern because the salinity change pattern could be described as the increasing function from the shoreline to offshore regions due to the continuous ground-water inflow in the adjacent watersheds. The salinity is increased from the submersion time to the high tide and decreased from the high tide to the exposure time.

• Journal of the Korean Society for Nondestructive Testing
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• v.35 no.2
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• pp.150-156
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• 2015

In this study, the effects of different mix proportions and fire scenarios (exposure temperatures and post-fire-curing periods) on fire-damaged concrete were analyzed using a nonlinear resonance vibration method based on nonlinear acoustics. The hysteretic nonlinearity parameter was obtained, which can sensitively reflect the damage level of fire-damaged concrete. In addition, a splitting tensile strength test was performed on each fire-damaged specimen to evaluate the residual property. Using the results, a prediction model for estimating the residual strength of fire-damaged concrete was proposed on the basis of the correlation between the hysteretic nonlinearity parameter and the ratio of splitting tensile strength.

• International Area Studies Review
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• v.14 no.1
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• pp.77-97
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• 2010

Recently, countries on the Caspian Sea were had heavily interested due to instability of international resource market. These countries having been developed basing on energy exports, especially Kazakhstan have drastically grown during a decades. However economy, heavily relied on the exports of energy, is influenced on fluctuation in the international energy price as well as sometimes exposed at Dutch disease. These days, Kazakhstan, increased trade and investment with Korea, has been on the rise as new supplier for energy. Therefore, economic change in Kazakhstan can be an important issue. In this paper, we analyze relations among oil price, interest rate, and real exchange rate during sample period from January 1999 to December 2008 expanding Balasa-Samuelson model. Empirical results present that oil price, interest rate, and real exchange rate mutually keep their balance. Eventually, we find out Kazakhstan has exposed at Dutch disease since oil price and interest rate have negative impacts on real exchange rate respectively.

• Clinical and Experimental Pediatrics
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• v.48 no.1
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• pp.34-39
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• 2005

Purpose : Perinatal complications associated with maternal smoking and alcohol ingestion in pregnancy have been well documented. But until now there has been no clinical data on it collected in our country. In this paper, we tried to research the association between maternal smoking and alcohol ingestion in pregnancy and the physical indices of the neonate at delivery among unmaried mothers from one charitable institution. Methods : We enlisted 125 unmarried with a history of smoking and alcohol consumption during pregnancy who delivered a baby in National Medical Center from March, 2001 to March, 2004 as a study group. As a control, 174 unmarried mothers without a history of smoking and alcohol were enlisted. Then, we compared the physical indices - birth weight, height, and the head circumference - of the neonates from both groups. Furthermore, we investigated the effects of the period and the quantity of maternal smoking and alcohol ingestion on the physical indices of the neonates from the both groups. Results : Low physical indices of neonates were found in the study group(either smoking group, or drinking group) compared with the control group. The quantity of smoking or drinking and the period of smoking or drinking have no significant effect on physical indices. Conclusion : We found that maternal smoking and alcohol result in the low physical index of neonates, and educational initiatives must be directed at expectant mothers to emphasize the harmful effects of smoking and alcohol ingestion in pregnancy.

• Journal of Korean Society of Disaster and Security
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• v.6 no.1
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• pp.73-78
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• 2013

This study aims to develop Drowning Management Index (DMI) to evaluate the effectiveness of drowning management in a region. In order to develop practical index to evaluate drowning management, downing contributors are examined. Drowning exposure rate is collected by survey. DMI is generated from South Korea and Australia for comparison. South Korea and Australia indicate similar number of drowning per 100 thousand people (1.7 South Korea, 1.4 Australia) but in DMI it turned out 9 times difference between two countries (15.5 South Korea, 1.67 Australia).