• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.1
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• pp.155-165
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• 2014

In this study, using a complex of physical, chemical, and biological evaluation factors, the ecological vulnerability to climate change were evaluated at each river in the Nakdong river basin. First, runoff, sediment rate, and low flow discharge changes according to AIB climate change scenario using the SWAT model were simulated. Also, for the assessment of chemical and biological factors, 48 points that water quality monitoring sites and ecological health measurement points are matched with each other was selected. The water quality data of BOD and T-P and the biological data of IBI and KSI in each point were reflected in the assessment. Also, the future rise in water temperature of the rivers in Nakdong river basin was predicted, and the impact of water temperature rise on the fish habitat was evaluated. The top 10 most vulnerable points was presented through a summary of each evaluation factor. This study has a contribution to river restoration or management plan according to the characteristics of each river.

• Korean Journal of Environmental Agriculture
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• v.10 no.2
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• pp.138-148
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• 1991

The object of this stduy was to investigate the pollution by Pb in rice plants which were cultivated in paddy field soils located near roadside areas and to discover the relationship between lead content in rice plants and soils. Samples of soils and rice plants were collected directly from paddy fields at various distances from highways and expressways located in Kyungpook province. The results obtained were as follows : 1. The average content of Pb in each part of the rice plant was 12.8ppm in roots, 4.8ppm in leaves, 4.3ppm in stems, and 0.4ppm in brown rice. 2. The content of Pb in roots showed highly positive correlation with the Pb content of the soil. 3. The Pb content in stems, leaves, and brown rice showed positive correlation with the Pb content in roots. 4. The content of organically bounded, carbonate, and sulfide Pb in soils showed highly positive correlation with the Pb content in roots. 5. The absorption ratio showed positive correlation with soil pH and negative correlation with the content of Fe in soils.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.17-24
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• 2021

The development of a new sorbent for carbon dioxide depends on several factors, such as fast adsorption/absorption velocity, hydrophobicity, and lower regeneration temperature than commercial sorbent. In this study, aminosilane grafted activated carbon was synthesized to capture CO2. Methyltrimethoxysilane (MTMS) and 3-aminopropyl-triethoxysilane (APTES) were used as the grafting precursor of the amine functional group. The APTES grafting activated carbon showed higher sorption property than MTMS used one. The characteristics of the separation mechanism of carbon dioxide were examined by measuring the adsorption capacity according to temperature and carbon dioxide partial pressure. The absorption capacity of carbon dioxide was similar to amine grafting activated carbon and activated carbon at 25℃, but amine-grafted activated carbon was higher at 75℃. The amine functional group-grafted activated carbon showed higher absorption capacity than activated carbon with a 1% carbon dioxide partial pressure. Aminosilane grafting of activated carbon was chemically absorbed but also showed the characteristics of physical adsorption. The reforming activated carbon with an amine functional group grafted solid absorption/adsorption sorbent would significantly impact the material engineering industry and carbon dioxide adsorption process. The functionalized sorbent is a high-performance composite material. The developed sorbent may have applications in other industrial processes of absorption/adsorption and separation.

• Proceedings of the Korean Environmental Health Society Conference
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• 2005.11a
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• pp.130-133
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• 2005

황사는 대기오염과 관련하여 심혈관계 및 호흡기계 질환으로 인한 사망 의 증가 등의 건강 영향으로 인해 관심의 대상이 되어왔다. 그러나 최근의 황사성분을 분석한 연구결과에 따르면 실제로 황사기간 동안에 전체먼지농도 중 조대먼지농도의 비율은 증가한 반면 미세먼지농도의 비율은 감소하였고 유해한 중금속의 농도도 별다른 변화를 보이지 않거나 오히려 감소하였다. 이에 본 연구에서는 서울시의 2000년부터 2002년, 2월부터 5월까지의 황사시기를 포함한 경우와 포함하지 않은 경우를 비교하여 황사현상으로 인한 대기먼지가 총사망에 미치는 영향을 비교하였다. 분석결과에 따르면 총사망에 미치는 대기먼지의 영향은, 황사시기를 포함하여 분석한 경우보다 황사시기를 제외하고 분석한 경우에서 더 큰 건강영향을 보였다. 즉, 황사시기를 제외하고 분석한 경우에서 대기먼지가 총사망에 미치는 위험의 크기가 더 큰 것으로 나타났다. 이는 황사의 화학성분 및 황사시 사람들의 행동양식의 변화와 같은 노출의 감소로 설명될 수 있으며 이는 도시 대기오염의 건강위해성을 평가함에 있어서 황사시기를 포함하여 분석하는 경우 도시 대기오염, 특히 대기먼지의 위해도를 과소평가할 가능성이 있으며, 지금까지 제안되는 기존의 연구결과보다 실제 도시 미세먼지의 건강영향이 훨씬 더 클 수 있음을 본 연구결과가 제시하고 있다.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.2
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• pp.194-200
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• 1985

To find out the relationships between the changes of soil chemical properties due to submergence and paddy rice yield, a laboratory and 9 field experiments on 9 soil series were carried out. From the field experiments, relative yields of no fertilizer yield to maximum yield were widely distrbuted from 54 to 76, although the correlation between no fertilizer yields and maximum yields was significant. Among the chemical ingredients of submerged soil, $NH_4-N$ only showed significant correlation with no fertilizer yields. From the laboratory experiments, pH were much increased in the soils high in no fertilizer yield than the others. There were no significant correlation between $NH_4-N$ contents of submerged soils and organic matters of dry soils. Soils low in available $P_2O_5$, low in organic matter, and high in clay of dry soil were negligible in increments of available $P_2O_5$ due to submergence, and efficiency of phosphorous fertilizer in those soils were remarkable. Soils extremely high in available $SiO_2$ of dry sail decreased in available $SiO_2$ due to submergence.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.5
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• pp.624-630
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• 2010

In order to investigate the effects of continual pre-plant application of liquid pig manure (LPM) on growth and quality of rice in double cropping system of rice and malting barley, the liquid pig manure was applied after harvesting rice and malting barley for 3 years. Field experiment was designed with non-fertilizer, chemical fertilizer (CF) 100% recommended by soil testing, rice (LPM 50%+CF 50%)+malting barley (CF 100%), rice (LPM 50%+CF 50%)+malting barley (LPM 50%+CF 50%), rice (LPM 100%)+malting barley (CF 100%) and rice (LPM 100%)+malting barley (LPM 100%). The yield of rice was increased by 13% with increasing culm length and No. of panicle per hill as 482 kg $10a^{-1}$ in rice (LPM 100%)+malting barley (LPM 100%) plot compare with 427 kg $10a^{-1}$ in rice (CF 100%)+malting barley (CF 100%) plot. Whereas, lodging index was high in rice (LPM 100%)+malting barley (LPM 100%) plot by increasing of internodes length from 3rd to 4th and decreasing of breaking strength. When the quality of milled rice was compare with rice (CF 100%)+malting barley (CF 100%) plot, it was decreased by increasing of protein contents and decreasing of rate of perfect grain in rice (LPM 100%)+malting barley (LPM 100%) plot. The content of amylose was not significant by 19.4~22.0%. Toyo-taste value was not different in LPM 100% and CF 100% plot. Rice could be grown with only liquid pig manure 100%, but considering yield and quality of rice and lodging risk, basal fertilization by LPM 50% and top-dressing by CF 50% application was recommended for rice cultivation.

• Economic and Environmental Geology
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• v.54 no.4
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• pp.409-425
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• 2021

Carbon dioxide has been known to be a typical greenhouse gas causing global warming, and a number of efforts have been proposed to reduce its concentration in the atmosphere. Among them, carbon dioxide capture and storage (CCS) has been taken into great account to accomplish the target reduction of carbon dioxide. In order to commercialize the CCS, its safety should be secured. In particular, if the stored carbon dioxide is leaked in the arable land, serious problems could come up in terms of crop growth. This study was conducted to investigate the effect of carbon dioxide leaked from storage sites on soil fertility. The leakage of carbon dioxide was simulated using the facility of its artificial injection into soils in the laboratory. Several soil chemical properties, such as pH, cation exchange capacity, electrical conductivity, the concentrations of exchangeable cations, nitrogen (N) (total-N, nitrate-N, and ammonia-N), phosphorus (P) (total-P and available-P), sulfur (S) (total-S and available-S), available-boron (B), and the contents of soil organic matter, were monitored as indicators of soil fertility during the period of artificial injection of carbon dioxide. Two kinds of soils, such as non-cultivated and cultivated soils, were compared in the artificial injection tests, and the latter included maize- and soybean-cultivated soils. The non-cultivated soil (NCS) was sandy soil of 42.6% porosity, the maize-cultivated soil (MCS) and soybean-cultivated soil (SCS) were loamy sand having 46.8% and 48.0% of porosities, respectively. The artificial injection facility had six columns: one was for the control without carbon dioxide injection, and the other five columns were used for the injections tests. Total injection periods for NCS and MCS/SCS were 60 and 70 days, respectively, and artificial rainfall events were simulated using one pore volume after the 12-day injection for the NCS and the 14-day injection for the MCS/SCS. After each rainfall event, the soil fertility indicators were measured for soil and leachate solution, and they were compared before and after the injection of carbon dioxide. The results indicate that the residual concentrations of exchangeable cations, total-N, total-P, the content of soil organic matter, and electrical conductivity were not likely to be affected by the injection of carbon dioxide. However, the residual concentrations of nitrate-N, ammonia-N, available-P, available-S, and available-B tended to decrease after the carbon dioxide injection, indicating that soil fertility might be reduced. Meanwhile, soil pH did not seem to be influenced due to the buffering capacity of soils, but it is speculated that a long-term leakage of carbon dioxide might bring about soil acidification.

• Journal of the Korean Chemical Society
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• v.53 no.6
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• pp.653-662
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• 2009

Developing effective tools for predicting absorption, distribution, metabolism, excretion properties and toxicity (ADME/T) of new chemical entities in the early stage of drug design is one of the most important tasks in drug discovery and development today. As one of these attempts, support vector machines (SVM) has recently been exploited for the prediction of ADME/T related properties. However, two problems in SVM modeling, i.e. feature selection and parameters setting, are still far from solved. The two problems have been shown to be crucial to the efficiency and accuracy of SVM classification. In particular, the feature selection and optimal SVM parameters setting influence each other, which indicates that they should be dealt with simultaneously. In this account, we present an integrated practical solution, in which genetic-based algorithm (GA) is used for feature selection and grid search (GS) method for parameters optimization. hERG ion-channel inhibitor classification models of ADME/T related properties has been built for assessing and testing the proposed GA-GS-SVM. We generated 6 different models that are 3 different single models and 3 different ensemble models using training set - 1891 compounds and validated with external test set - 175 compounds. We compared single model with ensemble model to solve data imbalance problems. It was able to improve accuracy of prediction to use ensemble model.

• Journal of the Korean Chemical Society
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• v.63 no.3
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• pp.166-182
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• 2019

This study examined teachers' difficulties that they encountered free semester science assessment and their problem solutions. Fifteen science teachers who had experiences of free semester teaching and assessment were selected by convenience sampling in this study. The participant teachers mentioned difficulties of accurate scoring in student self/peer assessment and suggested solutions of providing studetns with detailed assessment criteria and opportunities to practice assessment. The participant teachers mentioned a lack of objective assessment criteria for affective domain and suggested solutions of providing criteria prior to assessment and developing assessment framework. The participant teachers mentioned a lack of assessment tools and references for perforamnce assesement. The participant teachers mentioned difficulties of a large teacherstudent ratio for providng feedbacks to students and suggested solutions of decreasing teacher-student ratio and teaching load. The participant teachers mentioned difficulties of identifying student characteristics for assessment reporting and suggested solutions of decreaing teacher work load. The participant teachers mentioned a lack of teacher understanding of process based assessment and inactive attitude to performance assessment and suggested solutions of professional learning community and improving teacher perceptions on performance assessment. The participant teachers mentioned difficulties of a large teacher-student ratio and a lack of time for implementing assessment methods that they learned from professional development programs. With both teacher self-efforts and systematic support, these problems would be solved and success of free semester assessment would be achieved.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.6
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• pp.672-678
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• 2015

The types of hazardous and noxious substances (HNS) being transported by sea in Korea are at about 6,000, HNS transport volume accounts for 19% of total tonnage shipped in Korea, and the increase rate of seaborne HNS trade in Korea is 2.5 times higher than the average increase rate of the world seaborne HNS trade. Reflecting this trend, HNS spill incidents have been frequently reported in Korean waters, and there are increasing social demands to develop HNS management technology for the preparedness, response, post-treatment and restoration in relation to HNS spill incidents at sea. In this study, a risk-based HNS prioritization system was developed and an HNS risk database was built with evaluation indices such as sea transport volume, physicochemical properties, toxicities, persistency, and bioaccumulation. Risk scores for human health and marine environments were calculated by multiplying scores for toxicity and exposure. The top-20 substances in the list of HNS were tabulated, and Aniline was ranked first place, but it needs to be managed not by individuals but by HNS groups with similar score levels. Limitations were identified in obtaining data of chronic toxicity and marine ecotoxicity due to lack of testing data. It is necessary to study on marine ecotoxicological test in the near future. Moreover, the priority list of HNS is expected to be utilized in the development of HNS management technology and the relevant technologies, after the expert's review process and making up for the lack of test data in the current research results.