• Journal of Marine Life Science
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• v.7 no.2
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• pp.213-220
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• 2022

This study was conducted to investigate the effect of environmental factors such as water temperature and rearing density on the survival and growth of Litopenaeus vannamei under low salinity conditions. Overall, in the higher water temperature, the higher survival rate comes out and in the lower rearing density, the higher the survival rate does. In a study on feed efficiency, weight gain (WG) increased significantly as water temperature increased, and weight gain according to rearing density significantly decreased as rearing density increased. The growth rate of L. vannamei was faster when the water temperature was higher (water temperature 31℃) under low salinity conditions. In addition, in the evaluation of the growth rate according to the rearing density, it was confirmed that the growth rate was accelerated at a low rearinging density. It is believed that the results of this study will be usefully applied to the determination of the optimal rearinging density and breeding water temperature of L. vannamei in low salinity condition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05b
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• pp.149-153
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• 2003

In URD(Underground Residential Distribution) power cable, experiments of WVT(Water Vapor Transmission) test on the Base Resin accomplished to specimens which contained CB(Carbon Black), anti-oxidant to base resin and made by pressing to resin of pellet or lump form. a kind of specimens was HDPE(High Density Polyethylene), MDPE(Medium Density Polyethylene), LDPE(Low Density Polyethylene), LLDPE(Linear Low Density Polyethylene), PVC(Polyvinyl Chloride). as a results of WVT test, we saw that WVT ratio was HDPE < LLDPE < MDPE≒LDPE${\ll}$ PVC. WVT properties of PVC using for jacket showed properties 15-20 times more than MDPE or LLDPE. Therefore, to development of watertightness cable, our works present need of Changing in insulating materials.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.52-56
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• 2001

Experiments of 2 type on insulating compounds accomplished to change PVC using in URD(Underground) power cable jacketing. one was DB(Dielectric Breakdown) test on the pure base resins and the others were WVT(Water Vapor Transmission) test on the compounds which contained C/B(Carbon Black), anti-oxidant to base resin. a kind of specimens made by pressing to resin of pellet or lump form was HDPE(High Density Polyethylene), MDPE(Medium Density Polyehylene), LDPE(Low Density Polyethylene), LLDPE(Linear Low Density Polyethylene), PVC(Polyvinyl Chloride). As a results of AC DB and WVT test, we saw that strength of Insulation was HDPE> LLDPE = MDP E> LDPE and WVT ratio was HDPE

• Journal of Forest and Environmental Science
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• v.34 no.1
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• pp.61-65
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• 2018

To know if small changes in rearing water temperature and density affect the number of bacterial and fungal colonies in metamorphosed frogs, Dybowski's frog tadpoles were reared from Gosner 25-26 stages at either low ($1^{\circ}C$ low to ambient water temperature), ambient, or high ($1^{\circ}C$ high) water temperature (each 15 tadpoles in 20 L water) condition and at either low (10 tadpoles/20 L water), medium (20 tadpoles), or high (30 tadpoles) density condition. Immediately after metamorphosis, we sampled bacteria and fungi from skin, liver, and heart of six metamorphosed frogs, randomly selected for each treatment group. After separate incubation of bacteria and fungi on 3M Petrifilm plates, we counted the number of bacterial and fungal colonies appeared on the plates and compared the numbers among the temperature and density treatment groups. For temperature treatment, high-temperature group had fewer bacterial colonies, while low-temperature group had more fungal colonies than the other two groups. For density treatment, low-density group had fewer bacterial colonies than the other two groups, but the number of fungal colonies were not different among the groups. Our results suggest that small increased rearing water temperature and lowered rearing density could potentially reduce pathogens in farming frogs.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.52-56
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• 2001

Experiments of 2 type on insulating compounds accomplished to change PVC using in URD(Underground) power cable jacketing. one was DB (Dielectric Breakdown) test on the pure base resins and the others were WVT(Water Vapor Transmission) test on the compounds which contained C/B(Carbon Black), anti-oxidant to base resin. a kind of specimens made by pressing to resin of pellet or lump form was HDPE(High Density Polyethylene), MDPE(Medium Density Polyehylene), LDPE(Low Density Polyethylene), LLDPE(Linear Low Density Polyethylene), PVC (Polyvinyl Chloride). As a results of AC DB and WVT test, we saw that strength of Insulation was HDPE > LLDPE ≒ MDPE > LDPE and WVT ratio was HDPE < LLDPE < MDPE < LLDPE ≒ LDPE${\ll}$PVC. WVT of PVC using for jacket showed characteristic 15 times more than MDPE or LLDPE. Therefore, to development of watertightness cable, our works present need of Changing in insulating materials

• Fashion & Textile Research Journal
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• v.22 no.1
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• pp.112-118
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• 2020

This paper examined the water repellency, water proofing and water vapor permeability of twelve types of woven fabrics for sports wear clothing. Their physical properties were compared and discussed with the fabric structural parameters and surface finishing effect. A water repellent property of 100% was obtained in the coated or laminated water repellent finished fabrics; in addition, cotton/nylon breathable composite fabrics treated with a laminated finishing and with low fabric density showed a 90% water repellency. Water proofing fabric above 6,000 mm H₂O hydraulic pressure was achieved by coated or laminated finishing; however, high density fabric or medium-level coated fabrics exhibited 100% water repellent and low water proofing characteristics. Superior water vapor permeability characteristics with good water repellency and proofing properties were achieved at the 2.5 layered low density and with 0.7 - 0.9 cover factor nylon fabrics treated with hydrophilic laminated finishing. The regression analysis for examining the effects of fabric structural parameters and surface finishing such as coating and laminating to the water vapor permeability exhibited a high determination coefficient of fabric structural parameters of 63.5%; in addition,, main factors among fabric structural parameters appeared to be cover factor and fabric thickness per weight. Coating and Laminating factors exhibited determination coefficient of water vapor permeability parameters of 36.5%.

• Journal of the korean society of oceanography
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• v.35 no.4
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• pp.170-178
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• 2000

Low salinity water was observed during May in the Cheju Strait. Its structure and source were studied by using both the hydrographic data collected not only in the Cheju Strait during 1987-1989 but also in the wider area around Cheju Island extending to the Bank of Changjiang river in 1994 and the current data taken in the Strait during 1987-1989. The water had lower values of temperature, salinity, and density compared with the surrounding water and it was found in the surface layer outside of Tsushima Current Water 10-50 km off Cheju coast. The density of low salinity water was more dependent on salinity than on temperature. The low salinity water flowed into the Strait from the west as a series of intermittent waters whose size was variable in width and in thickness. The low salinity water was originated from the Chanajiang River Diluted Water. In the Cheju Strait, the water showed changes within 3 days on time and 30-50 km on space, and its sudden appearance was marked especially in May. Such strong variability and sudden appearance may be attributed to the beginning stage in May when the fresh water of Changjiang River Diluted Water starts to arrive in the Cheju Strait.

• The Korean Journal of Ecology
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• v.17 no.3
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• pp.241-249
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• 1994

Leaf diffusive resistance (LDR), stomatal density, length of guard cell and hair density of leaves of 6 oak species were determined under withdrawal of water, and their strategies of drought stress were analyzed by principal component analysis. LDR of Quercus acutissima, Q. aliena and Q. serrata increased earlier than those of the other species at high leaf water potential $({\Psi}_{leaf})$ or low water saturation deficit (WSD), which was an avoidance mechanism reducing damage by water stress. Q. variabilis with low stomatal density, small stomatal size and high hair density had avoidance mechanisms increasing LDR at high $({\Psi}_{leaf})$ However, Q. mongolica and Q. dentata increased LDR at low $({\Psi}_{leaf})$ as xeric species do. Results from principal component analysis on the 15 variables related to strategies of drought stress indicated that the 6 oak species were divided into 2 groups: (1) Q. acutissima, Q. aliena and Q. serrata as mesic habitat species and (2) Q. variabilis, Q. mongolica and Q. dentata as xeric habitat species. Among three xeric species Q. acutissima differed from the other two species in the drought strategies such as high hair density, low stornatal density, high leaf area ratio, stomatal closing at low $({\Psi}_{leaf})$ and small cell wall elasticity. The results could reasonably explain their drought strategies in natural habitat.

• The Korean Journal of Ecology
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• v.19 no.2
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• pp.165-178
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• 1996

We investigated the role of competition in adaptation to varying water availability levels for two ecotypically-differentiated populations of Impatiens pallida found naturally in low- vs. high-water environments. In a greenhouse experiment, seedlings were grown in pure cultures at two densities (n=1 and 2 plants per pot) and in mixed cultures (n=2) under low-, medium- and high-water treatments. The two populations were shown to be genetically distinct across the range of environmental conditions in the greenhouse experiment, confirming previous findings. The two populations had similar morphological responses to density and water availability in pure cultures and mixtures, but the population from the high-water environment showed a greater growth response to high water availability than did the population from the low-water environment and the difference in growth between the two populations decreased from the high-water to low-water treatment. Relative competitive ability of two populations were compared under three different water treatments and two densities. Differential response to watering treatment and density were not reflected in a difference in relative competitive ability. Relative yield totals were significantly greater than 1 overall. The niche differentiation suggested by RYTs>1 may be responsible for the lack of differential competitive effects observed for populations in the three vatering treatments.

• Journal of Life Science
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• v.17 no.10
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• pp.1330-1335
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• 2007

This study was developed to assess the antioxidative activity of aged black garlic extract on lipid peroxidation and low density lipoprotein (LDL). Antioxidative activity of aged black garlic extract on human low density lipoprotein (LDL) was investigated by monitoring a barbituric acid reactive substance (TBARS). Electron donating ability (EDA) of aged black garlic, ethanol extract was higher than that alliin and water extract. Aged black garlic water and ethanol extracts inhibited the $Cu^{2+}$ mediated oxidation of human LDL in a dose dependent manner at concentration of 10 and $20\;{\mu}g/ml$. Ethanol extract and water extract of aged black garlic almost completely inhibited J774 mediated LDL oxidation in electrophoretic mobility and conjugated diene. These results indicate that aged black garlic might play a protective antioxidant effects on LDL, probably affecting the structural properties for the LDL oxidation.