• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.310-310
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• 2017

'Gawaji 1', an early maturing and low amylose content rice variety adaptable to double cropping system with barley as later winter crop., was developed by the crop breeding team of Crop Research Division, GARES, Hwaseong, Korea in 2016. 'Gawaji 1' was derived from a cross between 'Baegjinju' and 'Sangmibyeo' in 2004. This variety had heading date of August 4 in Gyeonggi Province. It had a semi-elect plant type and resistance to lodging with strong culm. Its culm length was 67 cm. This variety had 15 tillers per hill and 104 spikelets per panicle. It was medium grain variety showing 1,000 grain weight of brown rice of 19.3g. Its protein contents of milled rice was 8.2% which was lower than 'Baegjinju'. Its milling ratio was 75.5% which was higher than 'Baegjinju'. The yield of milled rice was 5.0 MT/ha under the ordinary culture of the local adaptability test in 3 areas of Gyeonggi Province for three years. 'Gawaji1' is highly adaptable to Gyeonggi Province, especially to northern region of Han River.

• Journal of the Korean Society of School Health
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• v.20 no.2
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• pp.81-89
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• 2007

Purpose: The Purpose of this study was to compare stress level and stress coping behavior of elementary students in southern and northern area of Han river. Methods: This was a descriptive comparative survey using a convenience sample of 403 5^th-and 6^th-grade students. The data were analyzed by X²-test, t-test, ANOVA and multiple regression using SPSS 11.5 statistical program. Results: The level of stress and stress coping behavior according to northern and southern elementary students of seoul, Stress levels tended to increase more significantly with less satisfied life, more study time, in female students than male students. in northern students, and with more individual factors. With regard to stress coping behaviors. students with higher life-satisfaction tended to use active coping, and female students used more positive and mystic coping than negative coping. Conclusion: Students living in northern area, and more female students than male students showed a high level of stress, and students with a higher stress level were better able to cope with stress. Thus, it could be concluded that programs to lower stress levels are needed more than stress intervention programs.

• Korean Journal of Ichthyology
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• v.22 no.3
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• pp.206-209
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• 2010

A specimen of Redigobius bikolanus (29.0 mm SL) belonging to the family Gobiidae was collected by a hand net from the estuary of Changgo-cheon (river) in Andeok-myeon, Jeju Island, Korea. This specimen was characterized by having 26 lateral line scales, 7 predorsal scales, 7 transverse scales, anterior oculoscapular canal, preopercular canal, and four black spots between origin of anal fin and lower origin of caudal fin. The morphological characteristics of the specimen well matched those of Redigobius bikolanus previously reported. Thus, we newly add this species to the list of Korean fish fauna and propose its new Korean name, "Jeom-bak-i-mang-duk".

• Journal of Conservation Science
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• v.12 no.1 s.15
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• pp.26-30
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• 2003

We examined the species of charcoals excavated at the late paleotithic site of Suyanggae. Suyanggae is located on the riverbed of Han river near Banyans, central Korea. The charcoals belong to the post-glacial period (radiocarbon dates: $18,630\~16,400\;BP$). Only two species were identified. Most of samples (139 among 142) examined were Pinus spp. (diploxylon). The other 3 samples were Picea spp. The results suggest the upper layer at $235\~245\;cm$ below the ground level was formed during dry and warm post glacial period, predominated by two needle pines and lower layer at 270 cm below the ground layer during the last glacial maximum period, predominated by spruces.

• Journal of the Korean Society of Hazard Mitigation
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• v.4 no.3 s.14
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• pp.61-72
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• 2004

In this research, multi reservoir operation methods for reservoirs in Han River are proposed based on the single dam operation models using fuzzy control techniques. The result of fuzzy controled single dam operation has shown that it can improve flood controllability at the downstream of dams. Among the many control rules of fuzzy operation, a rule that shows the most effective flood control rate at the downstream has been selected as Ike operation rule. The simulated results for 1990 and 1995 flood events are compared with historical ones. As the results, it is founded that suggested models can reduce the inundation of upstream and keep the water elevation lower at downstream, which make the proposed models as the effective methods in multi reservoir operation.

• Journal of Korea Port Economic Association
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• v.17 no.1
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• pp.129-157
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• 2001

In Korea, the quantity of waste is excessive as a result of increases in population and consumption following industrialization. This has resulted in urban environmental problems, a shortage of landfills and pollution around landfills. Thus, there is a need to conduct research in order to find an effective long-term alternative. In Japan, there are more landfills at sea than there are on land. Based on projections for Korea, on-land landfills in the metropolitan area will be filled to capacity by 2020 and then be closed. This research recommends the construction of landfill sites at sea as an alternative waste disposal method. Its findings show that the most the suitable sites for landfills within the Seoul metropolitan area are the regions around Jangbongdo Island and Mueido Island. It also suggests that the best way to transport waste is through the Kyungin Canal from the middle collection center to the lower Han River. The estimated cost of constructing an at-sea landfill to be used for 50 years is approximately two trillion won, with a total construction time of 10 years. In the future, further research related to this study will be conducted in order to ensure that environmentally-friendly landfills are built.

• Journal of Korea Port Economic Association
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• v.17 no.1
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• pp.159-180
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• 2001

The quantity of waste has been increased due to the increase in population and consumption after industrialization. Accordingly it caused the urban environmental problems, the lack of landfill and the pollution around the landfill. Thus, it is necessary to research the adequate alternative in the long-term. In case of Japan, areas and quantities of landfills at sea are more great than those of landfills in land. And investigating our condition, landfills of the metropolitan area in land are to be fully filled with wastes up to 2020 and be closed. In this research, construction of landfill sites at sea is suggested as the alternative waste disposal method and it is suggested that in our country, the suitable landfill sites of the metropolitan area are the regions around Jangbong-do Island and Muei-do Island. It is expected that the best way to transport wastes is to transport through Kyungin canal from the middle collection center to the lower Han River. Rough cost for construction of landfill at sea, if it is used for 50 years, is expected to be 2 trillion won and total time to construct the landfill is expected to be 10 years. Many studies concerning to this research proposal are to be performed so that construction of landfills familiar to environment are to be accomplished.

• Journal of Environmental Science International
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• v.12 no.10
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• pp.1121-1129
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• 2003

We report the distributions of Sb and As in the surface sediment of the Yellow Sea and the coastal areas of Korea. The mean concentrations of Sb and As range from 0.68 ppm to 1.01 ppm and from 7.4 ppm to 15.8 ppm, respectively, and show relatively the high concentrations at the coast of Weolseong in the East Sea for Sb and at the coast of Gadeok Island in the South Sea far As. This may be due to the anthropogenic input of these elements via river and atmosphere from industry complex and agriculture regions around the study areas. Because of the difference of clay to silt proportion, the correlation between silt plus clay contents and Sb, As in the coastal surface sediment of Korea is not shown, the concentrations of Sb and As vary widely for the sample in which the silt plus clay contents are the same. Therefore, we suggest that the distribution patterns of Sb and As in surface sediment of the Yellow Sea and the coastal areas of Korea are mainly controlled by the anthropogenic inputs and the sediment characteristics. On the other hand, the Sb concentrations are lower than those of the lowest effect level which is the standard of judgment for contamination, while the As concentrations are higher than those of the lowest effect level. This implies that the surface sediments of the Yellow Sea and the coastal areas of Korea are considerably contaminated for As.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.11a
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• pp.179-182
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• 2009

Concrete containing styrene-butadiene latex is widely used, nowadays, as a protective system for bridge. Latex modification mortar have taken advantage of latex modification concrete advantage that is used in existing, Also, when repair, protection and sticking performance of concrete overlay waterproof agent were known as that are good. Replace and experimented from fine aggregate to recycled aggregate to secure economic performance than existing latex modification concrete. Recycled fine aggregate has low quality because it contains large amount of old mortar. So, its usage is limited to a lower value-add, such as the roadbed material etc. This study is purposed to improve the performance of mortar made of recycled fine aggregate. For this, recycled aggregate mortar was produced with latex, and fluidity, strength were examined. Test result indicate that mortar using recycled fine aggregate is higher compressive and flexural strength than mortar using river sand.

• Journal of Environmental Health Sciences
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• v.27 no.2
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• pp.60-66
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• 2001

Natural organic matters(NOMs) are found everywhere such as soil, surface and ground waters and consist of both humic and nonhumic components, and their heterogeneith makes each source unique. This study was carried to evaluate the removal characteristics of NOMs by mixing coagulants and the variation of apparent molecular weight distribution(AMWD) in coagulation process. Ratio of optimum coagulants dosage for removal of DOC and turbidity by mixing coagulants was 1.83 mM F $e^{3+}$/mM $Al^{3+}$. DOC removal increased at lower pH. The pH6 control focused on the removal of organic matters could reduce the amount of coagulant consumption by 2 to 3 times based on the pH8.5 of natural water. The dissolved organic matters in the natural water from the mid-stream of Han River were composed of the low molecular weight(LMW,<1 K) of 59.7%, and the medium and high molecular weight(M.HMW, 1~30 K) of 40.3%, respectively. At pH6, the DOC removal efficiencies of LMW(<1 K) and M.HMW(1~30 K) in coagulation process were 27~35%, 62~72%, respectively. The fraction smaller than 1 K was not eliminated to a noticeable degree, while the fraction of 1~30 K was relatively well removed. In conclustion, mixing coagulants were fairly effective in the removal of natural organic matter.r.