• 방사성폐기물학회지
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• 제14권3호
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• pp.245-251
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• 2016

발전소 해체 및 핵종누출 시 원자력 관련 시설 주변의 방사성오염 토양은 주민의 거주 및 공업용지로의 재사용을 위해 토양제염이 불가피하다. 본 논문에서는 기존 토양복원 기술을 생물학적, 물리/화학적, 열적 처리로 분류하고 각 기술의 원리 및 처리 물질을 분석 및 조사를 통해 방사성물질로 오염된 토양에 적용 가능한 기술을 선정하였다. 선정된 기술을 평가하기 위해 경제성, 적용성, 기술성을 고려하였다. 또한 High, Medium, Low로 가중치를 적용하여 평가하였다. 이에 따른 결과값을 바탕으로 방사성물질로 오염된 토양에 가장 적합한 토양제염 방법을 제시하고자 한다.

• 방사성폐기물학회지
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• 제19권1호
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• pp.39-49
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• 2021

The behaviors of various desorption agents were investigated during the desorption of cesium (Cs) from samples of clay minerals and actual soil. Results showed that polymeric cation exchange agents (polyethyleneimine (PEI)) efficiently desorbed Cs from expandable montmorillonite, whereas acidic desorption solutions containing HCl or PEI removed considerable Cs from hydrobiotite. However, most desorption agents could desorb only 54% of Cs from illite because of Cs's specific adsorption to selective adsorption sites. Cs desorption from an actual soil sample containing Cs-selective clay mineral illite (< 200 ㎛) and extracted from near South Korea's Kori Nuclear Power Plant was also investigated. Considerable adsorbed 137Cs was expected to be located at Cs-selective sites when the 137Cs loading was much lower than the sample's cation exchange capacity. At this low 137Cs loading, the total Cs amount desorbed by repeated washing varied by desorption agent in the order HCl > PEI > NH4+, and the highest Cs desorption amount achieved using HCl was 83%. Unlike other desorption agents with only cation exchange capabilities, HCl can attack minerals and induce dissolution of metallic elements. HCl's ability to both alter minerals and induce H+/Cs+ ion exchange is expected to promote Cs desorption from actual soil samples.

• 한국전기전자재료학회논문지
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• 제31권2호
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• pp.102-106
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• 2018

Recently, there has been an increasing interest in the use of graphene as electrode materials for supercapacitors. In this regard, graphene oxide (GO) films were prepared using GO slurry obtained by dispersing GO powder in deionized (DI) water. The degree of dispersion of GO powder in DI water depends on the concentration of GO slurry, pH, impurity content, GO particle size, types of functional groups contained in GO, and manufacturing method of GO powder. In this study, the dispersivity of the GO powder was improved by adjusting the pH using only DI water (without additives), and a uniform GO film was obtained. The GO film was reduced by exposure to xenon intense pulsed light for a few milliseconds, and the reduced GO film was used as electrodes of a supercapacitor. The supercapacitor was characterized using cyclic voltammetry (CV), charge-discharge cycle, and electrochemical impedance spectroscopy measurements, and the specific capacitance of the supercapacitor was found to be ~140 F/g from the CV data.

• 한국식품과학회지
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• 제37권1호
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• pp.129-133
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• 2005

Minimally processed and refrigerated(MPR) 셀러드의 미생물학적 안전성 및 저장성 증대를 위하여 이산화염소와 citric acid 처리를 이용하여 실험한 결과 총 호기성 세균을 3.75 log cycle, 효모와 곰팡이는 3.47 log cycle, 대장균은 3.41 log cycle, Listeria 속은 3.38 log cycle 감소시켰다. 물로 세척한 경우는 샐러드의 미생물을 효과적으로 제거하지 못한 반면 화학적 처리구는 생육 미생물을 3.3-3.7 log cycle 감소시킴으로써 식품의 미생물학적 안전성을 보장해 주었다. 또한 샐러드 저장 중 효소적 갈변 원인인 polyphenoloxidase의 활성을 감소시켜 대구조에 비해서 49.73%의 감소를 보였다. 따라서 이산화염소와 citric acid를 이용한 화학적 처리는 MPR 샐러드의 위생학적 안전성을 보장해 주고 또한 갈변 효소의 활성을 억제함으로써 저장성을 증대시키고 유통기간 연장에 도움이 된다고 판단된다.

• 한국철도학회논문집
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• 제8권6호
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• pp.520-524
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• 2005

It is consequential to reduce the environmental impact of a product for sustainable development in 21st Century. In the field of transportation, especially, the technological market concerned about reduction and assessment of greenhouse gas emission is expected to be extended. The LCA gas been esteemed and utilized as a realistic alternative greenhouse gas emission is expected to be extended. The LCA has been esteemed and utilized as a realistic alternative to improve the environment by the assessment of environmental impacts. In this study, simplified life cycle assessment(S-LCA), was performed to analyze the environmental impacts quantitatively, which were produced through the life cycle of a electric motor unit(EMU). The object of the present work is rth investigate main parameters of environmental impacts and to establish the plans to improve the environment impact of EMU. As a result of quantitative assessment for environmental impact and manufacturing, the EMU carbody made of SUS showed acidification(AD) and marine water aquatic ecotoxicity(MAET) the most, while that made of Mild showed high impact of global warning(GW) and abiotic resources depletion(ARD). For the SUS EMU, the high AD and MAET impact is occurred by the discharged pollutants during acid-washing process. Also, high value of GW and ARD for Mild EMU is resulted from the consumption of iron ore, coal and crude oil during manufacturing. Therefore, the environment impact of carbody would be decreased by enhancing of energy efficiency and the lightening the weight of it.

• 한국농공학회논문집
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• 제56권5호
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• pp.67-75
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• 2014

In this study, the large-scale hydraulic model test was performed to investigate the hydraulic characteristics for development of the non-power soil cleaning and keeping system at the dike gate. The outlet height, outflow number, outflow discharge, and outflow cycle were compared and analyzed. The non-power soil cleaning and keeping system was most effective at 11.2 mm in the outlet height. And then the mean outflow cycle was 1.09 sec, and the mean outflow discharge was $0.00164m^3/s$. The total outflow number increased gradually as the water level of a water tank increased, and the outlet height decreased. As a level of water tank decreased, the mean outflow cycle was lengthened, and the unit outflow discharge increased. This result showed this system was most effective. To remove the silty clay deposited in facilities, the methods of excavation, dredging, high pressure washing, etc have been applied to the tidal facilities such as land reclamation, a small size fishing port, and a harbor for maintenance. However, this is extremely cost-ineffective, whereas the non-power soil cleaning and keeping system will bring about an enormously positive economic effect. In addition, when the non-power soil cleaning and keeping system is applied to the dike gate of land reclamation, a thorough examination of the local tidal data and the careful system planning are required to prevent the disaster damage caused by flooding.

• Journal of Biosystems Engineering
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• 제28권5호
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• pp.449-456
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• 2003

A robot system was developed to pick desired colony. This robot system consisted of an image acquisition process which acquires the image information of colony, an illumination device which irradiates the object once when it gets the image of it, a picking head, a replicating head, a bed for fixing well-plates, and a sterilization device of sterilizing pin stained with colony. Picking pins were washed in an ultrasonic wave washing for takes ten seconds. Picking pins were dipped for sterilizing in alcohol for ten seconds. The time for resterilizing picking pins in a heater was five seconds. This performance test resulted 100% success rate for both the colony picking and the colony replication process. Considering the procedure in which 8 pins were smeared by colony, picked on a well plate, and sterilized as one cycle, the system could carry out one cycle in 110 seconds. It took about 138 minutes to pick around 600 colonies.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2005년도 제31회 KOSCO SYMPOSIUM 논문집
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• pp.78-84
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• 2005

The development of eco-friendly low pressure carburizing system with high pressure gas quenching (LPC_GQ, 500kg/charge) led to new stage in the fundamental case-hardening treatments. This is due to its ability to provide tighter tolerances on the carburizing process with notable reductions in distortion of the carburized and hardened workpiece. This system is characteristics by high uniformity and reproducibility of heat treatment results, absence of an intergranular oxidation layer, carburizing of complex shapes, reduced cycle time, low operating costs, simplified production, eliminate post washing, and reduced grinding costs.

• 열처리공학회지
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• 제19권5호
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• pp.262-269
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• 2006

The development of eco-friendly low pressure carburizing system with high pressure gas quenching(LPC-GQ, 500kg/charge) led to new stage in the fundamental case-hardening treatments. This is due to its ability to provide tighter tolerances on the carburizing process with notable reductions in distortion of the carburized and hardened workpiece. This system is characteristics by high uniformity and reproducibility of heat treatment results, absence of an intergranular oxidation layer, carburizing of complex shapes, reduced cycle time, low operating costs, simplified production, eliminate post washing, and reduced grinding costs.

• 자원리싸이클링
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• 제19권4호
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• pp.51-57
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• 2010

실리콘 웨이퍼공정에서 발생하는 실리콘 슬러지로부터 리싸이클링 공정으로 Si-SiC 혼합물을 분리 회수한 다음 기계적 합성법으로 Si-SiC-CuO-C 복합물을 제조하였으며, 리튬전지 음극물질로서의 가능성을 조사하였다. 실리콘 슬러지의 주요 불순물은 절삭유, 금속불순물 및 SiC를 들 수 있다. 오일세정-자력선별-산세척으로 절삭유와 금속불순물을 제거한 다음 고에너지 밀링법으로 Si-SiC-CuO-C 복합물을 합성하였다. 복합물의 충방전 용량과 사이클 특성을 조사한 결과, 수명에 따른 용량 유지 특성이 향상된 우수한 결과를 얻을 수 있었다. 복합물을 구성하는 SiC와 CuO 관련 물질은 실리콘의 부피팽창으로 인한 기계적 파괴 현상을 억제하는 요소로 작용하는 것으로 추정되며, 반면에 Fe 등과 같은 불순물은 전극의 충방전 용량을 감소시키는 요인으로서 전극물질 합성 전에 10 ppm 이내로 제거되어야 하는 것으로 판단된다.