• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.5
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• pp.593-600
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• 1999

The survival rates of Littorina brevicula exposed to experimental concentration regimes of TBTCl, HB and Cd on the large and the small size individuals during 80 days were $80\%$ at 0,9ppb TBTCl, 40 and $25\%$, respectively at 200ppb Hg, and 75 and $45\%$, respectively at 100ppb Cd. The growth rates of the experimental animals exposed to each concentration for 80 days was 0.023mm/day at control, 0.019mm/day at 0.1ppb and 0.014mm/day at 0.9ppb TBTCl, 0.022 mm/day at 5ppb, 0.008 mm/day at 200ppb Hg, and 0.017 mm/day at 5ppb, 0.008mm/day at 100ppb Cd. The respiration rates and excretion rates of the experimental animals exposed to chronic concentration of TBTCl, Hg and Cd were decreased until approximatively 40 days and increased after, Toxic effect of pollutants on L. brevicula was highest at TBTCl. The histological injury of L. brevicula exposed to TBTCl, Hg and Cd was shown at gill, digestive organ and muscle, respectively.

• Journal of Animal Environmental Science
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• v.8 no.1
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• pp.9-16
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• 2002

This study was conducted to develope the new solid separating system which can be efficiently and economically removed the solid parts in high pollutants concentration of pig slurry. The pollutants concentration, BOD$_{5}$ , COD and SS of the slurry used in this study was 15,990($\pm$2,389)mg/l, 20,004($\pm$5,512)mg/l and 26,486($\pm$5,935)mg/l, respectively. After removal of solid part in slurry, the pollutants concentration, BOD$_{5}$, COD and SS was change into 5,617($\pm$690)mg/l, 5,553($\pm$633)mg/land 1,456($\pm$341)mg/l, respectively in the Fixed biological membrane tank. The reduction of the pollutants concentration of suspend liquid through membrane will be allowed to greatly improve the water purification by an Activated sludge method. This separating system consisted of a temporary storage, a circulating tank and a Fixed Biological membrane tank. A temporary storage which has a draining system of screw type and an aeration device played a tremendous role in draining the solid by filled an aeration of 0.3 l/min. A Fixed Biological membrane tank of which a styrofoam filled in a 2/3 volume as a Biological media was fixed by a stainless steel net (pore size : 0.5mm) to separate the liquid layer of influx in them. The separating system efficiency factors were the speed of screw motor, cycle number of slurries in a circulating tank and moisture contents of solid effluent through the screw path. Although the pollutants concentration was very variable in temporary storage, the final concentration of $BOD_5$ and SS, except COD of the suspended liquid in a Fixed biological membrane were not different regardless of cycle number of a circulating tank. Moisture contents of effluent from temporary storage was 73% under the speed 1 ppm of screw motor and 62% under the 1/4rpm of it.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.1
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• pp.53-58
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• 2017

FRP Hybrid Bar, composed of an embedded steel and the coated composites with epoxy and glass fiber, is an effective construction material with tension-hardening performance and lightweight. The epoxy exposed to UV(Ultra Violet Rays) and FT(Freezing and Thawing) action easily shows a surface deterioration, which can cause degradation of bonding strength between inside-steel and outside-concrete. In the present work, surface inspection for 3 different samples of normal steel, FRP Hybrid Bar before UV, and FRP Hybrid Bar after UV test was performed, then concrete samples with 3 reinforcement types were prepared for accelerated FT test. Through visual inspection on 3 typed reinforcement, no significant deterioration like chalking was evaluated. The results from FT test to 120 and 180 cycles showed FRP Hybrid Bar exposed to UV test has higher bonding strength than normal steel by 106.3% due to enlarged bond area by silica coating. The 3 cases showed a similar bond strength tendency with increasing FT cycles, however a relatively big deviations of bond strength were evaluated in FRP Hybrid Bar after UV test due to loss of silica coating.

• Journal of Preventive Medicine and Public Health
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• v.19 no.1 s.19
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• pp.123-129
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• 1986

Fetal weight data from 84 litters of Sprague-Dawley rats were statistically analyzed for the effect of position in the uterine horn on fetal weight. The standard score obtained from the mean weight and standard deviation of all fetuses in a uterine horn were studied for position effect. In control group, the heaviest fetus occupied the middle position with a progressive decrease in weights toward the ovarian and cervical ends of the horn. But the effect related to position for the fetal weight was not statistically significant. In contrast, rats acutely or chronically exposed to carbon monoxide showed statistically significant positional differences of fetal weight within the uterine horns. The findings that the intrauterine position effect on fetal weight which is not signicant in control group may act one of confounders at the situation of transplacental toxicological studios.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.169-172
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• 2006

The IIA structures exposed to marine environment is subject to many different types of potential attack. The physical attack due to drying and wetting would increase the internal stress of concrete. The chemical attack resulting from the diffusion of ions$(Cl^-,SO_4^{2-},Mg^+)$ from seawater through the pores in concrete. Therefore the sea water resistance of concrete must be considered when it is used for structure in the ocean. The objective of this study is to evaluate chloride diffusion and corrosion characteristics of concrete when using the various concrete materials under marine environment. After 5 years of exposure, concrete incorporating 40% blast-furnace slag as replacement for type I cement with low w/c ratio of 0.42 and using the inhibitor shows excellent performance.

• The Korean Journal of Zoology
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• v.6 no.2
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• pp.1-5
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• 1963

SM계인 마우스 ♂♀를 정상군과 4개의 실험군, 즉 온열적 (33 $^{\circ}C$-60분, 매일 각각 폭로) 및 한냉적인 (5$^{\circ}C$-60분과 $0^{\circ}C$-60분, 매일 각각 폭로) 군으로 나누어 최소한 22일간 순화시킨 후 여지 전기영동에 의해서 Albumin /blobulin 비와 단백질 분할을 측정하고 또한 혈청전단백질량, 혈색소량, Hematocrit 비, 적혈구 포약성 및 간장 신장기관중량을 측정하였다. A/G 비와 전단백질양은 온열적 증가와 한랭적 증가의 각군이 정상군보다 유의하게 현저히 낮은 치를 나타내고 있다. 간장중량, 혈색소량 및 Hematocrit 비는 정상군보다 온열적 한랭적 조건하에서 낮은 치를 또한 나타내고 있다. 그러나 신장중량은 현저하게 증가된 치를 나타내고 있다. 온열적 한냉적 조건군의 간장에서의 조직학적 소견은 현저한 변화는 없고 다만 혈관적 변화만 나타내고 적혈구의 포약성은 거의 변화가 없다. 이와 같은 결과로 미루어 보다 온열적 한랭적의 효과로 인해서 주로 간장기능 즉 단백질대사에 이상을 초래하는 것으로 생각된다.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2007.04a
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• pp.129-132
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• 2007

In this study, for the establishment of the performance evaluation methods of repair material and method for reinforced concrete structure and the quality control standards of durability recovery method, the quantitative exposure data by exposure experiment under the coastal and normal atmosphere environment is accumulated and analyzed. Investigating and evaluating the result of exposure experiment during 54 months of exposure age under the coastal and normal atmosphere environment, Micro crack, swelling and spatting of surface coating material, crack of repair boundary parts and the great potential difference between repair part and non-repair part were somewhat generated. And the result shown that exposure specimen of coastal environment had lower electrode potential than exposure specimen of normal atmosphere environment.

• Journal of Korean Society of Forest Science
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• v.84 no.4
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• pp.424-431
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• 1995

This study was conducted to evaluate resistance and physiological responses of Zelkova serrata Makino seedlings to ozone in open-top chamber. One-year-old seedlings of Zelkova serrata were planted in pots in April and grown in greenhouse until August. The plants were transferred into two out-door open-top chambers with a dimension of 2.0 m in diameter and 2.0 m in height. First chamber served as a control and was supplied with ambient air. Ozone was added to the second chamber for 5 hours per day(10.00 AM-15.00 PM) for 23 consecutive days at 0.1 ppm. Each chamber housed 70 pots. Every two, three or five days after initiation of exposure, ten pots were randomly removed from the chamber and determined for the contents of chlorophyll a, b, total chlorophyll and ${\beta}$-carotene in the leaves. Photosynthesis and dark respiration were estimated by measuring $CO_2$ absorption in a gas exchange chamber and oxygen absorption by oxygen monitoring system, respectively. Superoxide dismutase(SOD) activity in the leaves was assayed by a xanthine oxidase method. First visible injury of translucent(water-soaked looking) spots appeared on the leaves 14 days after the initial exposure, and ozone accelerated senescence of old leaves. Contents of chlorophyll a and b decreased by 17%, and 31%, respectively, in ozone treatment two days after exposure. The decrease in chlorophyll b was greater than that of chlorophyll a. Content of ${\beta}$-carotene in ozone treatment decreased by 25% two days after initiation of exposure, but the reduction was recovered with time. Photosynthesis decreased by 45%, and the respiration increased by 28% in the ozone treatment. SOD activity started to increase 4 days after beginning of exposure and increased by 285% 7 days after exposure, and decreased to the level below the control treatment with the advancement of the visible injury.

• Journal of the Korean Wood Science and Technology
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• v.44 no.5
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• pp.785-808
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• 2016

The objective of this study was to investigate the effect of the short-term weathering on the flame retardant performance of wood coated with Dancheong. Flame retardants were applied on the Dancheong coated Korean red pine. Flame retardants applied panels were layed at the two conditions of outdoor exposure and artificial aging to assess the reliability of artificial aging. Flame retardants used were commercial products developed for historical wooden buildings. Scanning electron micrographs revealed the forming of carbonized membrane by melting of flame retardant on wood surface. These carbonized membranes may help delay the further combustion of wood. Flame retardant performance was assessed by measuring heat release rate (HRR) and total heat release (THR) by cone calorimetry. There was no difference in flame retardant performance between before and after 6-month outdoor exposure tests. And also no difference in flame retardant performance between before and after 2-week artificial aging which corresponds to 6-month outdoor exposure. Both tests showed the similar results of combustion characteristics.

• Journal of Conservation Science
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• v.33 no.2
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• pp.121-130
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• 2017

The currently used wax agents for preserving outdoor metal structures, despite their advantages, have disadvantages such as low endurance and reliability. These wax agents are easily damaged by acid rain, dust, moisture in the air, yellow dust, and air pollutants, resulting in corrosion within a short period after the initial conservation treatment. In addition, aged wax can also exhibit changes in the color or gloss, and also give a sense of difference in the surface. Given these existing problems, it is necessary to develop improved materials for metal preservation. Therefore, this study analyzed the characteristics and applications of the existing wax coating agents in order to identify their disadvantages and to develop a better material for metal preservation. In this regard, this study developed a perilla oil based compound wax and conducted experiments to test its endurance. The new compound wax agent was exposed to outdoor and acid rain conditions: it showed four times and 1.5 times the endurance of the existing wax agents in outdoor and acid rain conditions, respectively. In addition, the new agent seems to be more durable and protective as evidenced by the chromaticity, polish maintenance, and contact angle results. Further, although it is 1.3-1.8 times thicker than the existing agents, the new agent shows a more even surface. Based on these findings, it can be concluded that the new compound wax agent based on perilla oil is a better alternative to the existing was coating agents.