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        검색결과 12

        1.
        2023.05 구독 인증기관·개인회원 무료
        Natural uranium-contaminated soil in Korea Atomic Energy Research Institute (KAERI) was generated by decommissioning of the natural uranium conversion facility in 2010. Some of the contaminated soil was expected to be clearance level, however the disposal cost burden is increasing because it is not classified in advance. In this study, pre-classification method is presented according to the ratio of naturally occurring radioactive material (NORM) and contaminated uranium in the soil. To verify the validity of the method, the verification of the uranium radioactivity concentration estimation method through γ-ray analysis results corrected by self-absorption using MCNP6.2, and the validity of the pre-classification method according to the net peak area ratio were evaluated. Estimating concentration for 238U and 235U with γ-ray analysis using HPGe (GC3018) and MCNP6.2 was verified by 􀟙-spectrometry. The analysis results of different methods were within the deviation range. Clearance screening factors (CSFs) were derived through MCNP6.2, and net peak area ratio were calculated at 295.21 keV, 351.92 keV(214Pb), 609.31 keV, 1120.28 keV, 1764.49 keV(214Bi) of to the 92.59 keV. CSFs for contaminated soil and natural soil were compared with U/Pb ratio. CSFs and radioactivity concentrations were measured, and the deviation from the 60 minute measurement results was compared in natural soil. Pre-classification is possible using by CSFs measured for more than 5 minutes to the average concentration of 214Pb or 214Bi in contaminated soil. In this study, the pre-classification method of clearance determination in contaminated soil was evaluated, and it was relatively accurate in a shorter measurement time than the method using the concentrations. This method is expected to be used as a simple pre-classification method through additional research.
        3.
        2015.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, using soil brick with combined effective microorganisms and emergent plants was identified which it can increase the effect of conservation and improvement of water. Lab-test was consist of four kind of reactors and each of reactors were A(rawwater), B(soil brick), C(emergent plant) and D(soil brick+emergent plant). Iris pseudoacorus, Phargmites australis, Typha angustifolia and Zizania latifolia were used for emergent plant. Evaluation of application on various environment were performed on agricultural waterway and pond. The pH measurement test of soil brick was performed due to evaluate whether a strong alkaline water flows out of the soil brick. Result of lab-test, removal efficiency of D was better than removal efficiency of A presenting 20.9%, 27.9% 21.5%, 33.8% and 58.4% for CODCr, BOD5, TN, TP and TSS respectively. Removal efficiency of soil brick on agricultural waterway was revealed to be 49.5%, 45.0%, 43.7%, 37.3% and 28.6% for CODCr, BOD5, TN, TP and TSS respectively. And removal efficiency of soil brick on the pond was revealed to be 12.7%, 10.5%, 9.32%, 10.4% and 36.3% for CODCr, BOD5, TN, TP and TSS respectively. Result of pH measurement test of soil brick was neutral which was about 6 to 8.
        4,000원
        4.
        2014.07 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper examines the pounding problem between adjacent decks subjected to strong earthquakes. The elastomeric bearings in an isolated bridge reduce the stresses on the superstructure and cushion the impact by transferring smaller seismic forces to the substructure. On the other hand, these bearings also allow large horizontal displacement of the superstructure due to seismic forces. Bridges having various supporting soil conditions and different frequency ratios between adjacent decks are investigated by numerical analysis. In the analysis, decision making is conducted whether the collision took place or not and, the magnitude of pounding force and the duration time of collision are obtained and the results are discussed.
        4,000원
        5.
        2013.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        According to natural frequency of soil, characteristics of earthquake responses of an isolated containment building in nuclear power plants are examined. For this, earthquake response analysis of seismically isolated containment buildings in nuclear power plants is carried out by strictly considering soil-structure interactions. The structure and near-field soil are modeled by the finite element method while far-field soil by consistent transmitting boundary. The equation of motion of a soil-structure interaction system under incident seismic wave is derived. The derived equations of motion are solved to carry out earthquake analysis of a seismically isolated soil-structure system. Generally, the results of this analysis show that seismic isolation significantly reduces the responses of the soil-structure system. However, if the natural frequency of the soil is similar to that of the soil-structure system, the responses of the containment buildings in nuclear power plants rather increases due to interactions in the system.
        4,200원
        6.
        2013.10 구독 인증기관·개인회원 무료
        Forest resource development including plantation and thinning has severely influenced on the forest ecosystems. In this study, we compared differences of soil invertebrate communities between a larch planted forest and a natural deciduous forest. Soil invertebrates were collected at 6 sampling sites in the natural deciduous forest and at 9 sampling sites in the larch planted forest in June and September, 2013. Each study site was set in 1 ha and soil samples were collected using a soil core (5.5 cm diameter and 4.5 cm height). After sampling soil invertebrates, the invertebrates were extracted using Tullgren extractor for 72 hours. In total, 1,194 individuals and 22 taxa of soil invertebrates were identified in this study. Among them, Collembola was the most dominant taxa (41% of abundance). Abundance of the larch planted forest was higher two times than that of the natural deciduous forest. The results of this study provide fundamental information on soil invertebrate fauna before the forest managements. In the further study, we will examine the effects of various types of forest management on the community of soil invertebrates.
        9.
        2018.10 서비스 종료(열람 제한)
        This study was conducted to improve the economy, quality, and load of Soil paving concrete by using waste materials such as Oystery and Dolomitic to solve strength reduction and durability reduction caused by hardening agents in Korea. According to the results of the study, for the curing expenses, the Fine part agreement (FC) and the Furnace slag power lower (BS) are 5:5, It was possible to verify that the best results were obtained in terms of the quality of cement mortar when the natural organic lime and dolomitic lime were mixed at a ratio of 5:5.
        10.
        2017.04 서비스 종료(열람 제한)
        Due to frequent localized torrential downpours caused by environmental contamination, collapses of retaining wall structure have increased, so that it is required to enhance structural strongness. This research focuses on the stability and effectiveness of the soil-nailed natural surface(SNS)”method, which is eco-friendly and functions as retaining wall structure.
        11.
        2015.02 KCI 등재 서비스 종료(열람 제한)
        For 63 soil series distributed in Jeju Island, natural uncultivated soils in each soil series were collected, and their physicochemical properties and their concentrations of 19 heavy metals including 8 heavy metals which are regulated by Korean Soil Environment Conservation Law, were analyzed. Moreover, the correlations between physicochemical properties and heavy metal concentrations, and between heavy metal concentrations were analyzed. The heavy metals distributed in the higher concentrations and the lower concentrations with arithmetric mean value, were Mn(730 mg/kg) and Ba(493 mg/kg), and Hg(0.146 mg/kg) and Tl(0.096 mg/kg), respectively. The correlations between pH(H2O) and heavy metals(Hg, Ni, Co, Se), between pH(NaF) and heavy metals(Hg, Ba, Se, Tl), and between organic matter content and heavy metals(Hg, Tl) were significant at the 0.01 level. From the correlations between heavy metal concentrations, there were 22 where there were significant at the 0.01 level and they showed positive correlation. Among those, the heavy metals showing the correlation higher than r=0.5, were Sb-V(0.878), Mo-Sn(0.867), Co-V(0.654), Co-Sb(0.648), Be-Sn(0.546), and Sn-Tl(0.528).
        12.
        2014.09 KCI 등재 서비스 종료(열람 제한)
        In this study, as a fundamental study for the remediation of the radionuclides-contaminated soil, the adsorption of cobalt, strontium, and cesium on natural soil and kaolin were experimently investigated and adsorption characteristics were evaluated by using several adsorption kinetic and isotherm models. The pseudo-first-order kinetic model (PFOM), pseudo-second-order kinetic model (PSOM), one-site mass transfer model (OSMTM), and two compartment first-order kinetic model (TCFOKM) were used to evaluate the kinetic data and the pseudo-second-order kinetic model was the best with good correlation. The adsorption equilibria of cobalt, strontium, and cesium on natural soil were fitted successfully by Redlich-Peterson and Sips models. For kaolin, the adsorption equilibria of cobalt, strontium, and cesium were fitted well by Redlich-Peterson, Freundlich, and Sips models, respectively. The amount of adsorbed radionuclides on natural soil and kaolin was in the order of cesium > strontium > cobalt. It is considered that these results could be useful to predicting the adsorption behaviors of radionuclides such as cobalt, strontium, and cesium in soil environments.