• Journal of Korean Society of Environmental Engineers
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• v.38 no.12
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• pp.667-675
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• 2016

Nanoscale zero-valent iron (nZVI) has been effectively applied for environmental remediation due to its ability to reduce various toxic compounds. However, quantification of nZVI reactivity has not yet been standardized. Here, we adapted colorimetric assays for determining reductive activity of nZVIs. A modified indophenol method was suggested to determine reducing activity of nZVI. The method was originally developed to determine aqueous ammonia concentration, but it was further modified to quantify phenol and aniline. The assay focused on analysis of reduction products rather than its mother compounds, which gave more accurate quantification of reductive activity. The suggested color assay showed superior selectivity toward reduction products, phenol or aniline, in the presence of mother compounds, 4-chlorophenol or nitrobenzene. Reaction conditions, such as reagent concentration and reaction time, were optimized to maximize sensitivity. Additionally, pretreatment step using $Na_2CO_3$ was suggested to eliminate the interference of residual iron ions. Monometallic nZVI and bimetallic Ni/Fe were investigated with the reaction. The substrates showed graduated reactivity, and thus, reduction potency and kinetics of different materials and reaction mechanism was distinguished. The colorimetric assay based on modified indophenol reaction can be promises to be a useful and simple tool in various nZVI related research topics.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.84-84
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• 2017

직립식 마늘파종기는 마늘 종구를 한 알씩 집어 올려 중간이송컵으로 이송하는 자세교정컵과 배종부와 자세교정컵에서 낙하된 마늘종구를 땅속으로 파종하는 구조로 설계 제작되었으며,전라북도 익산시에 테스트베드를 구축하여 기계파종을 통한 파종기의 성능개선연구를 수행하였다. 기계파종은 1차년도 기존 파종기의 성능을 개선한 7조식 시제품과, 국내산과 스페인산 마늘을 파종하였으며, 11조용 참여기업의 기존 파종기를 이용하여 테스트베드에서 수행하였다. 비가 온 뒤의 땅에 파종한 라인의 샘플링 자료조사 결과(5m 구간 기준으로 체크) 결주율이 각각 17.81%, 35.6%로 평균적인 결주율이 0.57%인 일반 기상상태와 비교하면 매우 높은 결주율을 보이는 것을 알 수 있다. 마늘 파종법에 대한 결과로, 총 4가지의 파종법을 사용하였으며, 사용한 파종방법에는 2조 병목식 스페인식 파종법, 11조식 트랙터용 파종법, 7조식 트랙터용 파종법, 6조식 이양기용 파종법이다. 이 4가지 파종법 중에서 3가지 파종법에 대한 성장률에 대해서 조사를 해보았다. 11조식의 경우에는 제주도식 파종을 하여 비닐 멀칭이 되어있지 않으며, 7조식의 경우에는 비닐 멀칭이 되어있는 파종방식을 사용하였고, 2조식 병목식 스페인식 파종법의 경우에는 자유낙하 방식으로 비닐 멀칭의 유무에 따라 성장률에 대해서 조사를 하였다. 결주율은 파종된 마늘 중 샘플링한 데이터에 대해서 얼마나 파종이 잘되었는지에 퍼센트로 나타낸 것으로 11조식의 경우 비닐멀칭도 없고 비온 뒤에 파종 되어 파종시기에 문제가 있는 것으로 사료됨. 비가오지 않은 날씨에서 측정한 7조식 1차년도 성능개선 시작품의 결주율은 0.57%로 우수하게 나타났다. 발아율은 파종된 마늘 중 샘플링한 데이터에 대해서 다립파종 되어서 미성장된 것과 결주율을 합하여 퍼센트로 나타낸 것으로 시제품으로 개발한 7조식 파종기는 스페인산과 국내산 마늘의 발아율이 모두 90% 이상으로 나타났으며, 차이점은 파종시기의 차이에 따라 발아율의 차이가 있는 것으로 사료(토양, 재배환경 및 기후에 따른 변동요인이 많음)되며, 이는 파종법의 종류뿐만 아니라 비닐멀칭의 온도유지가 마늘 성장률에 얼마나 영향을 끼치는지에 대한 병행연구도 필요한 것으로 나타났다. 마늘의 성장률에 대해서는 아직 표준화, 정형화 되어있는 측정방법이 없기 때문에 이를 표준화, 정형화를 할 필요가 있다. 향후 이와 같은 결과를 토대로 직립식 마늘파종기의 성능을 더욱 개선시키는 연구를 지속적으로 수행할 계획이다.

• Journal of the Korean earth science society
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• v.28 no.3
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• pp.324-342
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• 2007

This study reports petrography and geochemical characteristics of the basalt lava flows in Seongsan-Ilchulbong area, the easternpart of Jeju island, Korea, to understand the evolutionary processes of magma. Basalt lavas are classified into the Pyoseon-ri basalt and the Seongsan-ri basalt. The Pyoseon-ri basalt is dark-gray colored with many vescicles, and mainly consists of olivine, feldspar and rarely of clinopyroxene as phenocrysts. The Seongsan-ri basalt is largely aphanitic basalt and bright-gray colored, divided into two lava-flow units: lower lava flow (B1) and upper lava flow (B2) by the intercalated yellowish lapillistone and paleosol. The lavas plotted into sub-alkaline tholeiitic basalt and alkaline basalt series. The tholeiitic basalts have characteristically higher $SiO_2,\;FeO^T$, and CaO contents, but lower $TiO_2,\;K_2O,\;P_2O_5$ and other incompatible elements compared to the alkali basalts. The tholeiitic basalts have higher $SiO_2$ to the same MgO contents than the alkalic basalts. The contents of Ni, Cr, and MgO show a strong positive correlation, which indicates that low-MgO phases like plagioclase and titanomagnetite were important during the differentiation of magma. The contents of incompatible elements against that of Th show a strong positive correlation. The chondrite-nomalized REE patterns of tholeiitic and alkalic basalts are subparallel each other. LREEs contents of the former are lower than, but HREEs contents are similar to the latter. They both are similar to their K/Ba ratios. The primitive-mantle normalized spider diagram demonstrates that the contents of Ba and Th of all basaltic magma are enriched, and yet Cr, Ni are depleted. The tholeiitic and alkalic basalts may be originated from a different degree of the partial melting of the same mantle material source, and one shows a higher degree of the partial melting than the other.

• Korean Journal of Environmental Agriculture
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• v.19 no.3
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• pp.218-222
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• 2000

Wasted${\cdot}$rested mine areas give lots of effect on around-environmental changes after mining development. Leaching water at reclaimed land has been eluted from the solid components through physical, chemical, biological procedures by waters percolated through reclaimed site. The element analysis of waste tungsten ore tailing, leaching water analysis and removal of heavy metal by zeolite were performed to investigate the influent of acid rain on the released contents of H. M. The heavy metal contents in leaching water were determined to be As $1.21\;{\sim}\;1.54\;ppm$, Pb $0.11\;{\sim}\;0.15\;ppm$ and $SO_4\;^{2-}$ was $302\;{\sim}\;378ppm$. As deionized water and simulated acid rain (pH 3,4) were percolated through columns packed tungsten ore tailing, the amount of Mn, Na, Ca which were dissolved by pH4 solution was higher than those by distilled water. However, W and Mo were eluted easily by high pH solution. The change of heavy metal concentration by column experiment packed zeolite was effective a little because heavy metals were adsorved much more by zeolite.

• Journal of Food Hygiene and Safety
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• v.5 no.3
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• pp.139-158
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• 1990

Heavy resposibility is placed on the veterinarian and the livestock and aquatic animal producers to observe the period for withdrawal of a drug prior to marketing to assure that illegal concentrations of drug residues in meat, milk, egg, fish and other animal foods do not occur. This is essential from a public health standpoint because levels of residues in excess of those legalIy permitted in edible tissues may produce injurious effects when consumed over a long time span. With greater use of animal drugs of chemicals required in production of food crops, livestock and aquatic animals, the possibility of human being continuously exposed to drug and chemical residues for a life time is unequivocally evident. Korean authorities concerned Ministry of Agriculture and Fishery and Ministry of Health and Social Affairs, have recenly made their own regulations to control chemical residues in beef, pork and chicken independently. Consequently, inspection for the chemical residues also have been or will be carried out by the two authorities concerned without any cooperations. It is undoubtfulI to have a single regulation and national residue program for control residual chemicals in animal foods and that the tolerance levels should be established in milk, egg, and freshwater fish. Besides, we have no complete standard methods to analyze the residual chemicals and the methods have not been evaluated their efficiency, precise, accuracy and limit of detection. In this paper, the analytical methods and national residue programs in foreign countries are introduced and discussed and the status of animal food safety in this country is also reviewed.

• Korean Journal of Poultry Science
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• v.28 no.3
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• pp.215-224
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• 2001

Since nitrogen(N) is a volatile compound affected by many environmental factors, determining the N content of manure tends to be difficult. Upon arrival in the laboratory, the manure should be moist and refrigerated. Manure samples will have variable N contents due to drying temperature, and the presence of soil in the sample will affect N content. Acidification of the sample prevents ammonia volatilization and should be done before drying. It is recommended that manure samples be pretreated with a strong oxidizing agent, KMnO$_4$, followed by digestion under reduced conditions (reduced Fe-$H_{2}$ $SO_{4}$ ), which achieves a complete recovery of both $NO_{3}$ -N and $NO_{2}$ -N without a low recovery of $NH_{4}$ -N, resulting in a more accurate determination of N content. Accuracy of results for N content determined by recently developed rapid analysis techniques in the field should be tested by comparison with results obtained at laboratories using approved standard methods. Most commonly, the Kjeldahl system is used to determine manure N content. More research is needed on the effects of species, breed, age and individuals on the nutrient contents of manure. The procedures for manure sampling on the farm, shipping and handling of the sample until it reaches the laboratory, and the methods of sampling of the manure at the laboratory must be studied. Development of animal agricultural laboratories where feed, manure, soil, and water are all analyzed by appropriate specialists is needed.

• Korean Journal of Medicinal Crop Science
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• v.7 no.3
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• pp.205-212
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• 1999

This study was carried out to examine the effect of polyethylene film color and removing time of the mulching film in yacon (Polymnia sonchiiolia Poepp. & Endl.). The plant height on nonmulching was smaller about 10 cm or larger with 112cm than on other mulches ranged with $134{\sim}139$ cm at harvesting, and other characters examined were similar to that of plant height. The weight of tuberous root per plant was heavier on mulches ranged with $0.79{\sim}0.91$ kg than on non-mulching with 0.61 kg. Among the kind of mulches, plant height was the tallest with 139 cm in combination and declined in order of transparent, green and black polyethylene films. Yields among colored polyethylene films were the heaviest with 0.91 kg per plant in combination, 0.88 kg in black and 0.84 kg in green. In growth and yield full mulching untill harvesting was more effective than the other removed mulching treatments. It was effected on growth promotion at early growth stage, soil temperature and water preservation.

• Korean journal of applied entomology
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• v.50 no.2
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• pp.83-96
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• 2011

This study was conducted to investigate the influence of natural degrading polymer film covering in rice paddies on the benthic macroinvertebrate community structure in Dangsu-dong, Suwon, Gyeonggi-do from May 2009 to September 2009. We compared 5 treatments: golden apple snail farming (GF), natural degrading polymer film + organic farming (NOF), natural degrading polymer film + chemical farming (NCF), conventional farming (CF), and no fertilization (NF) as the control. The total number of species was highest in NOF followed by GF, NF, NCF, and CF. The total number of individuals was highest in NOF followed by NCF, CF, NF, and GF. The Dominance index (DI) ranged from 0.43 to 0.95. The highest dominance index was in GF followed by NCF, NF=CF, and NOF. The species diversity index (H') for each experimental plot ranged from 0.49 to 2.93. The average species diversity index was highest in NOF followed by NF, GF, CF, and NCF. After the natural degrading polymer film covered the paddies, the benthic macroinvertebrates tended to recover, but leeches and aquatic beetles increased. Mollusca and Annelida, which are sensitive taxa, decreased in both species and individual numbers after the soil was covered with the natural degrading polymer film. The number of species tended to recover. However, the number of individuals continued to decrease.d, especially individuals. Since then, the number of species tended to recover. However, the number of individuals decreased.

• Journal of the Korean Geotechnical Society
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• v.27 no.2
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• pp.53-62
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• 2011

During the construction of vertical cutoff walls, filtration of bentonite slurry into the adjacent soil formation fabricates a layer of bentonite filter cake on the wall surface. The bentonite filter cake possesses much lower hydraulic conductivity compared to that of backfill materials in the cutoff wall. Hydraulic conductivity of bentonite filter cakes formed with three different types of bentonites has been measured by performing the modified fluid loss test under various pressure levels. Three different mixture ratios, 4, 6, and 8%, were selected for fabricating bentonite filter cakes to represent common field conditions. Two analysis methods for interpreting the experimental data from the modified fluid loss tests were employed to estimate hydraulic conductivity of the bentonite cakes. The range of hydraulic conductivities of the three bentonite cakes is between $2.15{\times}10^{-11}\;m/s$ and $2.88{\times}10^{-10}\;m/s$ which is 1 to 2.7 orders of magnitude lower than that of the design cutoff wall backfill. The stress distribution and thickness of the bentonite cakes were also evaluated in this paper.

• Korean Journal of Medicinal Crop Science
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• v.15 no.3
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• pp.210-214
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• 2007

The study was carried out to establish in vitro microtuber production from leaf and petiole explant cultures of Pinellia ternata. Culture conditions were optimized by investigating the effect of plant growth regulators, different media, and gelling agents on the efficiency of microtuber indurtion. Among the different combinations of plant growth regulators tested, the combination of 0.1 mg/l 2,4-Dichlorophenoxyacetic (2,4-D) and 0.5 mg/l 6-benzylaminopurine (BAP) showed the highest yield fer microtuber production from leaf (3.9) and petiole (4.7) explant culture on MS medium far 6 weeks. SH(Schenk and Hildebrandt) medium was the most effective medium for microtuber induction and the half strength SH medium was better than SH medium for microtuber production from both leaf and petiole culture. Gelrite was better than agar in the formation of microtubers and 4% Gelrite showed the highest number of microtubers per explant frome leaf (5.9) and petiole (7.8) culture. Germination rate of microtubers after cold storaged for one months long was 86% from in vitro culture and 43% from autoclaved soil.