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        검색결과 27

        1.
        2020.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        축산 폐수는 고농도의 영양염류와 중금속을 함유하고 있어, 배출될 때 수질을 악화시킨다. 기존 처리 기술과 비교하여 bioremediation은 축산 폐수 처리에 유능하다. 특히, 미세조류는 오염물질 제거에 잠재력을 가지고 있다. 본 연구에서는 Ankistrodesmus bibraianus를 이용하여 축산 폐수 내 영양염류 (질소 (N), 인 (P))와 중금속 (구리 (Cu), 아연 (Zn))의 제거 가능성을 평가하고, A. bibraianus의 최적배양조건을 확립하였다. 연구결과, 최적 배양조건은 28°C, pH 7, 광주기는 14 : 10 h로 설정되었다. N과 P의 단일 처리구 (500, 1,000, 5,000, 10,000 mg L-1)에서 제거효율은 각각 22.9~80.6%와 11.9~50.0%였다. 또한, N과 P의 복합 처리구에서 제거효율은 각각 16.4~58.3%와 7.80~49.8%였다. Cu와 Zn의 단일 처리구 (10, 30, 50 mg L-1)에서 제거효율은 각각 15.5~81.5%와 6.28~34.3%였다. 유사하게, Cu와 Zn의 복합 처리구에서 제거효율은 각각 16.7~74.5%와 5.58~27.5%였다. 또한 영양염류 (N 및 P)와 중금속 (Cu 및 Zn)의 성장 및 제거효율을 축산 폐수에 적용할 수 있음을 나타냈다. 본 연구의 결과에 따르면 A. bibraianus는 축산 폐수 내 영양염류와 중금속 제거에 이용할 수 있을 것으로 사료된다.
        4,200원
        2.
        2018.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Applicability of corrosion inhibitor was evaluated using pilot scale water distribution pipe simulator. Calcium hydroxide was used as corrosion inhibitor and the corrosion indices of the water were investigated. Corrosion indices, Langelier saturation index (LI) increased by 0.8 and calcium carbonate precipitation potential (CCPP) increased by 9.8 mg/L. This indicated that corrosivity of water decreased by corrosion inhibitor and the effects lasted for 18 days. Optimum calcium hydroxide dose was found to be 3~5 mg/L for corrosion inhibition. We suggest that monitoring of CCPP as well as LI need to be conducted to control corrosivity of water.
        4,000원
        3.
        2023.01 KCI 등재 서비스 종료(열람 제한)
        The advanced oxidation treatment using persulfate and zero-valent iron (ZVI) has been evaluated as a very effective technology for remediation of soil and groundwater contamination. However, the high rate of the initial reaction of persulfate with ZVI causes over-consumption of an injected persulfate, and the excessively generated active species show a low transfer rate to the target pollutant. In this study, ZVI was modified using selenium with very low reactivity in the water environment with the aim of controlling the persulfate activation rate by controlling the reactivity of ZVI. Selenium-modified ZVI (Se/ZVI) was confirmed to have a selenium coating on the surface through SEM/EDS analysis, and low reductive reactivity to trichlroethylene (TCE) was observed. As a result of inducing the persulfate activation using the synthesized Se/ZVI, the persulfated consumption rate was greatly reduced, and the decomposition rate of the model contaminant, anisole, was also reduced in proportion. However, the final decomposition efficiency was rather increased, which seems to be the result of preventing persulfate over-consumption. This is because the transfer efficiency of the active species (SO4-∙) of persulfate to the target contaminant has been improved. Selenium on the surface of Se/ZVI was not significantly dissolved even under oxidation conditions by persulfate, and most of it was present in the form of Se/ZVI. It was confirmed that the persulfate activation rate could be controlled by controlling the reactivity of ZVI, which could greatly contribute to the improvement of the persulfate oxidation efficiency.
        4.
        2022.01 KCI 등재 서비스 종료(열람 제한)
        Environmental contamination by organic compounds are not only restricted to water, but extends to soil and groundwater as well. However, highly oxidized compounds, such as halogenated organics and nitro-compounds, can be detoxified employing reducing methods. Permeable reactive barrier is one of the representative technologies where zero-valent metals (ZVMs) are employed for groundwater remediation. However, organics contaminates often contaminate the unsaturated zone above the groundwater. Despite the availability of technologies like soil vapor extraction and bioremediation, removing organic compounds from this zone represents several challenges. In this study, the reduction of nitrobenzene to aniline was achieved using zero-valent iron (ZVI) under unsaturated conditions. Results indicated that the water content was an important variable in this reaction. Under dry conditions (water content = 0.2%), the reduction reaction was inhibited; however, when the water content was between 10% and 25% (saturated condition), ZVI can reduce nitrobenzene. Palladized iron (Pd/Fe) can be used to reduce nitrobenzene when the water content is between 2.5% and 10%. The reaction was evaluated over a wide range of temperatures (10 – 40 °C), and the results indicated that increasing the temperature resulted in increased reaction rates under unsaturated conditions.
        5.
        2021.12 KCI 등재 서비스 종료(열람 제한)
        Organic contaminants can be released into water environments due to chemical accidents and exist as dissolved and non-aqueous phase liquids (NAPL). Fenton oxidation was tested for bisphenol A and nitrobenzene as model organic contaminants in dissolved and NAPL states. Fenton oxidation was successfully applied for both of the dissolved and NAPL states of the two pollutants and the results indicated that a quick treatment was needed to reduce the risk from a chemical accidents instead of carrying out oxidation after the contaminants dissolve in water. A set of Fenton reactions were tested under seawater conditions because chemical accidents often occurs in the ocean. Chloride ions act as radical scavengers and inhibit Fenton oxidation. The reaction rate is inversely proportional to salt contents and the reduced reaction rate can be compensated by increasing the quantity of the oxidizing agents. The current study showes that Fenton oxidation could be applied as a quick treatments for organic contaminant in dissolved and NAPL state organic contaminants released as a result of leaks or chemical accidents.
        6.
        2020.12 KCI 등재 서비스 종료(열람 제한)
        In this study, the applicability of reduction-oxidation-linked treatment was evaluated for nitrobenzene and a by-product by analyzing the reaction kinetics. Nitrobenzene showed very low reactivity to persulfate that was activated using various methods. Nitrobenzene effectively reacted through the reduction process using Zero-Valent Iron (ZVI). However, aniline, a toxic substance, was produced as a by-product. Reduction-oxidation-linked treatment is a method that can allow the oxidative degradation of aniline after reducing nitrobenzene to aniline. The experimental results show improved reactivity and complete decomposition of the by-product. Improved reactivity and decomposition of the by-product were observed even under conditions in which the reduction-oxidation reaction was induced simultaneously. No activator was injected for persulfate activation in the process of reducing oxidant linkage, and the activation reaction was induced by ferrous iron eluted from the ZVI. This indicates that this method can be implemented relatively simply.
        7.
        2020.01 KCI 등재 서비스 종료(열람 제한)
        Oxidative degradation of phenol, three monochlorophenols (2-chlorophenol, 2-CP; 3-chlorophenol, 3-CP; 4-chlorophenol, 4-CP), four dichlorophenols (2,3-dichlorophenol, 2,3-DCP; 2,4-dichlorophenol, 2,4-DCP; 2,5-dichlorophenol, 2,5-DCP; 2,6-dichlorophenol, 2,6-DCP), and two trichlorophenols (2,4,5-trichlorophenol, 2,4,5-TCP; 2,4,6-trichlorophenol, 2,4,6-TCP) was conducted with heat activated persulfate. As the number of chlorinations increased, the reaction rate also increased. The reaction rate was relatively well fitted to the zero-order kinetic model, rather than the pseudo-first order kinetic model for the reactions at 60℃, which can be explained by insufficient activation of the persulfate at 60℃, and the oxidation reaction of 2,4,6-TCP at 70℃ was relatively well fitted to the pseudo-first order kinetic model. The oxidation reaction rate generally increased with increase of persulfate concentration in the solution. 2,6-dichloro-2,5-cyclohexadiene-1,4-dione was found as a degradation product in a GC/MS analysis. This compound is a non-aromatic compound, and one chlorine was removed. This result is similar to the result of previous studies. The current study proved that heat activated persulfate activation could be an alternative remediation technology for phenol and chlorophenols in soil and groundwater.
        8.
        2018.11 KCI 등재 서비스 종료(열람 제한)
        Bioremediation has been recognized as a suitable alternative to conventional methods of removing contaminants, and it uses fungi, bacteria and microalgae. In contrast to other organisms, microalgae are unique in that they have the ability to perform photosynthesis like plants and to utilize organic/inorganic carbon substrates, in a process called phytoremediation. Microalgae can populate a reaction site rapidly and enhance the bioremediation efficiency. In this study, Chlorella vulgaris was used to evaluate the removal potentials of the nutrients (N and P) and heavy metals (Cu and Zn) from swine wastewater. The optimum growth conditions for Chlorella vulgaris and the removal potentials of N, P, Cu, and Zn from synthetic wastewater using Chlorella vulgaris were investigated. Based on the results, the applicability of this microalga to on-site wastewater treatment was examined. Optimal growth conditions for Chlorella vulgaris were established to be 28℃, a pH of 7, and light and dark cycles of 14:10 h. As the concentrations of the nutrients were increased, the efficiencies of N and P removal efficiencies by Chlorella vulgaris were decreased in the single and binary mixed treatments of the nutrients, respectively. Further, the efficiencies of Cu and Zn removal also decreased as the heavy metals concentrations added were increased, both in the single and binary mixed treatments. In addition, the efficiency of Cu removal was higher than that of Zn removal. Our results indicate that Chlorella vulgaris could be used in treatment plants for the removal of nutrients and heavy metals from swine wastewater.
        9.
        2014.02 KCI 등재 서비스 종료(열람 제한)
        In Korea, the chemical oxygen demand(CODsed) in freshwater sediments has been measured by the potassium permanganate method used for marine sediment because of the absence of authorized analytical method. However, this method has not been fully verified for the freshwater sediment. Therefore, the use or modification of the potassium permanganate method or the development of the new CODsed analytical method may be necessary. In this study, two modified CODsed analytical methods such as the modified potassium permanganate method for CODMn and the modified closed reflux method using potassium dichromate for CODCr were compared. In the preliminary experiment to estimate the capability of the two oxidants for glucose oxidation, CODMn and CODCr were about 70% and 100% of theoretical oxygen demand(ThOD), respectively, indicating that CODCr was very close to the ThOD. The effective titration ranges in CODMn and CODCr were 3.2 to 7.5 mL and 1.0 to 5.0 mL for glucose, 4.3 to 7.5 mL and 1.4 to 4.3 mL for lake sediment, and 2.5 to 5.8 mL and 3.6 to 4.5 mL for river sediment, respectively, within 10% errors. For estimating CODsed recovery(%) in glucose-spiked sediment after aging for 1 day, the mass balances of the CODMn and CODCr among glucose, sediments and glucose-spiked sediments were compared. The recoveries of CODMn and CODCr were 78% and 78% in glucose-spiked river sediments, 91% and 86% in glucose-spiked lake sediments, 97% and 104% in glucose-spiked sand, and 134% and 107% in glucose-spiked clay, respectively. In conclusion, both methods have high confidence levels in terms of analytical methodology but show significant different CODsed concentrations due to difference in the oxidation powers of the oxidants.
        10.
        2013.10 KCI 등재 서비스 종료(열람 제한)
        This study was carried out to compare the characteristics of seed germination and the first stage of growth in Cynanchum wilfordii (Maxim.) by different light conditions such ass fluorescent light, dark and light emitting diode (LED). There was not much difference from the germination rate of C. wilfordii (Maxim.) in different light conditions for 10 days. The highest of germination rate occurred over 91.11 percentage by LED red condition at 26℃. Also mean germination velocity and promptness index were represented the highest results of 2.3 ea/day and 52.67 under red light, respectively. But mean germination time under both LED red and blue light was represented low data that it takes over three days for germinating of seed. Even though handling both LED red and blue lights, the germination uniformity was not constant. These results may help our understanding of variations in germination characteristics for C. wilfordii (Maxim.) seeds treated under different light conditions.
        11.
        2012.12 KCI 등재 서비스 종료(열람 제한)
        This study was carried out to select the appropriate medium (especially, carbon and nitrogen source, potassium phosphate and pH) for somatic embryogenesis in order to develop the rapid mass production system in suspension culture of Oplopanax elatus Nakai. Direct somatic embryos were obtained from root explants in the hormone free suspension culture (MS). Combination of NH4NO3 and KNO3 at the ratio of 1650 (mg/l) : 1900 (mg/l) obtained the better result to produce somatic embryo in suspension culture. MS medium supplemented with 170mg/l KH2PO4. The addition of 1 and 3% sucrose was effective for formation of embryogenic callus. Therefore, this report will be helped to improve the establishment for suspension culture in Oplopanax elatus Nakai.
        12.
        2012.10 KCI 등재 서비스 종료(열람 제한)
        This study was investigated seed germination of Rheum undulatum L. depends on storage temperature (-20, 5℃ and room temperature), germination temperature (5, 15, 25 and 40℃) and a soaking treatment (no soaking, 2 days and 4 days). There was not much difference from the germination rate of R. undulatum L. in storage temperature conditions for 8 weeks. The highest of germination rate occurred over 80 percentage at 25℃. When R. undulatum L. was soaked with tap water for four days, the average values of germination velocity and germination day were represented of 1.7 ea/day and 1.68 days. These results may help our understanding of variations in germination characteristics for R. undulatum L. seeds treated under various germination conditions.
        13.
        2012.06 KCI 등재 서비스 종료(열람 제한)
        억새 수집종의 초장 길이를 조사한 결과, 개화 전과 후 전체 생육기간 동안 200 cm 이상 우량한 생육을 나타낸 개체 자원은 India에서 수집한 억새 MS013이며, 개화 후에는 MS005, MS010, MS011, MS014 억새도 200 cm 이상의 생육을 보여주었다. 대부분의 억새 수집종의 경우 분얼수가 2-3개 정도로 나타났다. 엽장의 길이가 100 cm 이상인 수집종은 MS001, MS002, MS005, MS012, MS013, MS014로 6종이며, 엽폭은 1-2 cm 사이가 63%이상으로 대부분의 수집종들이 이에 속하였으며, MS002, MS003, MS005 억새의 엽폭은 2 cm 이상으로 잎이 넓은 것을 확인할 수 있었다. MS005 억새는 초장, 간경, 마디수, 분얼수 뿐만 아니라, 엽장, 엽폭에 있어서도 다른 지역에서 수집한 억새보다 수치가 높은 것을 확인하였으며 바이오에너지용 억새로서의 가치가 있다고 사료된다.
        14.
        2012.04 KCI 등재 서비스 종료(열람 제한)
        This study is part of research to develop the technology for managing major medicinal crops after harvest. We studied the optimal germination conditions of Cynanchum wilfordii (Maxim.) Hemsl. The mean germination time (MGT) of C. wilfordii seeds was higher after soaking for 4 days after storage at 5℃ for 8 weeks, than with germination at 25℃ (3 days). However, the germinative energy (GE) decreased as the number of days soaking increased. The greatest germination rate (83.3±8.8%) was at 25℃ with no soaking of seeds stored at -20℃ for 8 weeks. Based on these results, we characterized the germination conditions of a major medicinal crop.
        15.
        2012.04 KCI 등재 서비스 종료(열람 제한)
        This study evaluated the germination rate of Rheum palmatum L. in Korea as affected by storage temperature, germination temperature, and a soaking treatment. The germination rate of R. palmatum L. stored at various conditions for 8 weeks was 〉 60%. The highest germination rate occurred at 25℃. The germination point of R. palmatum L. with soaking was started 1 day after application, and non soaked seeds germinated in 2 days. When R. palmatum L. was soaked with water, the germination rate was lower, but mean germination velocity was the highest. These results may help our understanding of variations in germination characteristics for seeds treated under different germination conditions.
        16.
        2012.04 KCI 등재 서비스 종료(열람 제한)
        본 연구는 미국 수수 수집종의 작물학적 특성 및 생리활성을 검정하기 위하여 수행되었다. 대부분의 미국 수수 수집종은 200 cm 이상의 큰 초장을 보였으며, 간경 또한 2cm 이상의 값을 나타냈다. 수수 수집종 중에서는 Sweet-N-Sterile(#4)이 가장 우량한 수수의 생장 특성을 보였다. 수수의 DPPH를 이용한 활성 검정 결과, Premium stock(#1), Early Sumac(#7), SS Silage(#9), WGF Grain Sorghum(#11) 4개의 수집종에서 기존의 항산화제인 α-tocopherol과 BHA와 비슷한 활성을 보였고 BHT보다는 높은 활성을 보였다. 항미생물 실험결과 BMR Gold I(#3)이 가장 높은 활성을 나타냈으며, 특히 Escherichia coli에서 125 μg/ml으로 높은 활성수치를 나타냈다.
        17.
        2011.06 KCI 등재 서비스 종료(열람 제한)
        1. 수수 성숙기에 간장 길이를 조사한 결과 6개체(12.2%) 가 300 cm 이상의 길이로 바이오매스가 우량한 것으로 파악되었으며, 10개체(20.4%)정도는 200~300 cm 사이의 평균 길이를 나타내었다. 2. 성숙기의 수수 줄기 직경에는 큰 차이를 보여준 개체는 없었으며, 대부분의 수수 수집종들은 2.2±0.1 cm 정도의 직경을 갖는 것으로 드러났다. 3. 본 연구에 시험한 수수 수집종들은 엽장이 60~70 cm 정도의 길이에 속하는 유전자원이 22 개체가 되는 것으로 나타났으며, 7개체는 70 cm 이상되는 것으로 나타났다. 4. 엽형은 49% 정도의 개체가 협단으로 분류되었고, 대부분의 엽맥색은 백색으로 나타났다. 5. 본 연구에 사용된 대부분의 수수의 수형은 반밀수 타원형이 많은 것으로 나타났으며, 수장은 평균적으로 20~30 cm에 달하는 것으로 나타났다.
        18.
        2011.04 KCI 등재 서비스 종료(열람 제한)
        본 연구는 수수의 성숙 종자로부터 캘러스유기 및 재분화 효율 조사하기위하여 수행되었다. 배발생 캘러스 형성을 살펴보기 위해 생장조절제 효과를 조사하였다. 수수 성숙종자로부터 캘러스 유기에 적합한 생장조절제 종류와 농도는 2 mg/L 2,4-D인 것으로 나타났다. 배발생 캘러스의 고효율 빈도는 B5 배지에 2 mg/L 2,4-D을 첨가하였을 때 가장 양호한 것으로 나타났다. 배발생 캘러스로부터 식물체 재분화는 BAP와 IBA를 넣은 MS 배지가 가장 적절한 것으로 나타났다. BAP 농도가 높을수록 신초재분화가 활발하였다. 따라서, 본 연구 결과로부터 수수 기내배양시 신초와 발근 형성에 효과적인 생장조절제 조합은 0.5 mg l-1 BAP와 0.25 mg l-1 IBA인 것으로 나타났다.
        20.
        2006.03 KCI 등재 서비스 종료(열람 제한)
        건축물의 초고층화에 따라 최근 고성능 콘크리트의 사용이 증가하고 있다. 이러한 고성능 콘크리트는 고강도, 고유동, 고내구성 등 다양한 성능을 발휘하지만, 화재시 폭열에는 약한 것으로 알려져 있다. 본 연구는 PP섬유 혼입 및 마감재 변화에 따른 고성능 RC 기둥의 폭열방지 성능을 검토한 것이다. 실험결과 내화시험 후 폭열특성으로, 먼저 플레인의 경우 심한 파괴 폭열과 함께 철근이 노출됐고 내화뿜칠로 마감한 고성능 콘크리트는 내부 수분의 영향으로 플레인보다 더욱 심한 폭열을 나타냈다. 또한, 마감재 변화에 따른 시험체의 폭열특성으로는 내화도료로 마감한 경우가 가장 우수한 폭열방지 효과를 나타냈으며 폴리프로필렌 섬유를 0.1%혼입한 콘크리트는 3시간 가력 내화시험 후 가장 안전한 폭열방지 성능을 입증하였다.
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