• 청정기술
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• 제6권2호
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• pp.85-92
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• 2000

제강슬래그의 재활용 범위를 확대하기 위한 방안으로 제강슬래그를 여재로 이용하여 축산폐수 처리효과를 조사하였다. 제강슬래그를 접촉용 여재로 활용한 순환식 폐수처리 장치를 이용하여 기존의 시설에서 처리된 축산폐수를 재처리한 결과 pH는 제강슬래그의 특성으로 인하여 상승하였으며 질소와 인의 농도를 효과적으로 낮추었으며 COD와 BOD도 감소하였다. 축산단지의 현장실험 결과 여재로 사용한 제강슬래그는 부유물질을 효과적으로 제거하였으며 유입 농도의 갑작스런 변화를 완화하였다. COD와 BOD의 경우 재처리수에서 항상 유입 폐수보다 낮아졌으나 유입수의 농도에 영향을 받았다. 에이징된 제강슬래그를 열처리 한 경우 free-CaO 성분의 증가로 열처리를 하지 않은 경우에 비하여 처리수의 pH 상승 정도가 커졌으며 인 제거 특성도 향상되었다.

• 한국해양학회지:바다
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• 제24권4호
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• pp.519-534
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• 2019

여름철 인공호수(간월호, 부남호)로 부터의 담수방류시 천수만 수질(영양염, 유기물, 미량금속)에 미치는 영향을 평가하기 위해 2011년 6, 7, 8, 10월에 평상시와 담수방류 시기 각 2회씩의 해수를 채취하였다. 담수가 방류되면 용존 무기 질소(DIN)의 농도가 만내의 모든 수층에서 약 3-4배 증가하였고, 평상시 암모니아성 질소(NH₄⁺-N)가 우세하다가 담수방류시 질산성 질소(NO₃^--N)가 우세하였다. 용존 무기인(DIP)의 경우 내만 표층에서 절반으로 감소하였고 저층에서는 1.5배 증가하였으며 규산염(Si(OH)₄)은 내만 저층에서 2배 증가하는 모습을 보였다. Redfield ratio는 담수 방류시 인 제한 환경으로 바뀌었다. 용존 유기 탄소(DOC) 및 질소(DON)는 약 2배 증가하였고, 입자상 유기 탄소(POC), 질소(PON), 인(POP) 및 생물기원 규소(Bio-SiO₂)는 내만 표층에서 약 2배 이상 증가했다. 용존 금속(Fe, Co, Ni, Cu)은 내만의 표층에서 증가하였으나, 용존 Cd의 경우 만의 표층에서 절반으로 감소하였다. 이와 같은 결과로 미루어 볼 때 영양염, 유기물 및 금속 농도가 높은 인공호수의 물이 만으로 유입되면, 천수만 내의 영양염 및 용존 유기물, 금속농도가 증가하고, 식물플랑크톤 대증식이 발생하여 표층에서 산소 과포화, 저층에서 빈산소를 발생시킨다. 빈산소와 함께 내만의 저층에서는 매우 높은 농도의 영양염(DIN, DIP, Si(OH)₄) 농도가 존재하였다. 수질 평가 지수값을 통해 천수만의 부영양화 정도를 평가한 결과, 평상시에는 3등급 이하로 나타나다가 방류시 5등급으로 바뀌게 됨을 알 수 있었다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.727-730
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• 2001

Electrical wire explosion (EWE) is characterized by great current density and rapid metal heating, which make itself an ideal tool for nano-materials manufacturing technology. The EWE requires a high voltage electric-energy source. In the current experimental set-up a high voltage capacitor is used for the purpose. Hence, a power supply that is capable of charging the capacitor to a target voltage is required. One of the special requirements is the precise controllability of the stored energy level in the capacitor. Through this study a high voltage capacitor charger using a series resonant converter technology has been developed for the production of nanosize powder. A load capacitor of $32{\mu}F$ can be charged up to 20kV by the developed capacitor charger and discharged through a gap switch and a copper wire.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 춘계학술대회 논문집
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• pp.70-73
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• 1997

The purpose of this study is to research and develop poly(p-phenylene)(PPP)-based carbon obtained by pyrolyzing electrochemically prepared PPP as a anode of rocking chair batteries. Disordered carbon materials were obtains by heat-treating of PPP films in a nitrogen atmosphere at 4$0^{\circ}C$ to 110$0^{\circ}C$ for 1 hour. The carbon prepared by heat treatment showed a broad x-ray diffraction peak having characteristics of disordered carbon. Carbon electrodes were charged and discharged at a current density of 0.1㎃/$\textrm{cm}^2$. First discharge capacity of 267㎃h/g and 34% of charge/discharge efficiency were observed from PPP-based carbon prepared at $700^{\circ}C$.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.715-718
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• 2001

This study uses traditional alum coagulation and sedimentation process to treat CMP wastewater from cleaning after polishing. The primary goal is to successfully recycle both solid fines and water for semiconductor manufacturing. Results indicated that CMP wastewater may be successfully treated to recover clean water and fine particles by alum coagulation. The optimum operating conditions for coagulation are as fellowing: alum dosage of 10 ppm, pH at 5, rapid mixing speed at 800 rpm, 5 min rapid mixing time, and long slow mixing time. The treated water with low turbidity and an average residual aluminum ion concentration of 0.23 ppm may be considered for reuse. The settled sludge after alum coagulation contains mainly SiO$_2$particle with a minor content of aluminum (1.7 wt%) may be considered as raw materials for glass and ceramic industry.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.518-521
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• 2003

LCA (Life Cycle Assessment), that unifies the scale of various environmental impacts, and simulated annealing are applied to optimizing electrolysis of wastewater from PCB (Printed Circuit Board) production. The changes of environmental impact can be quantified with LCA and the total changes of environmental impacts can be expressed as a function of power consumed, Cu recycled, $Cl_2$, NOx and SOx discharged through restriction of feasible reactions. In a single-variate condition, the environmental optimum can be easily obtained through plotting and comparing each environmental impact value. In 8V potentiostatic electrolysis, the lowest environmental impact can be achieved after 90min. To optimize a multi-variate conditional system, simulated annealing can be applied and this can give the quick and near optimum in complex systems, where many input and output materials are involved, through experimentally measured values without a theoretical modeling.

• Journal of Advanced Marine Engineering and Technology
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• 제39권8호
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• pp.833-837
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• 2015

Li-air batteries have a promising future for because of their high energy density, which could theoretically be equal to that of gasoline. However, substantial Li-air cell performance limitations exist, which are related to the air cathode. The cell discharge products are deposited on the surfaces of the porous carbon materials in the air electrode, which blocks oxygen from diffusing to the reaction sites. Hence, the real capacity of a Li-air battery is determined by the carbon air electrode, especially by the pore volume available for the deposition of the discharged products. In this study, a simple and fast method is reported for the large-scale synthesis of carbon nanoballs (CNBs) consisting of a highly mesoporous structure for Li-air battery cathodes. The CNBs were synthesized by the solution plasma process from benzene solution, without the need for a graphite electrode for carbon growth. The CNBs so formed were then annealed to improve their electrical conductivity. Structural characterization revealed that the CNBs exhibited both an pore structure and high conductivity.

• 환경위생공학
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• 제10권2호
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• pp.13-22
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• 1995

Most of small- scale livestock facility have difficulties to treat organic wastewater by activated sludge process as distinguished feces and urine. The organic wastewater discharged have characteristics of slurry, high concentration of BOD, 55 etc. This study was performed to estimate suitable condition for the application of packing materials, air flow, pollutant load and so on as important parameter to treat organic wastewater by thermopile oxlc process. As a result obtained at this experiments the most suitable condition for BOD load, air flow indicate 3.0kg · m$^{-3}$ day$^{-1}$,50 ∼ 100L· min$^{-1}$ m$^{-3}$, respectively, and we knew that it was necessary to add waste contained high calories to degrade about 80% of pollutant among waste- water. It showed that plastic material can be used as packing media because it can be provided as inhabitation for microorganism owing to intensity of material and characteristic of keeping moisture.

• 한국분무공학회지
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• 제12권3호
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• pp.131-137
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• 2007

This is an experimental study on characteristics of engine performance and discharged materials in common-rail type diesel engine. The bio-diesel fuel is mixed with the diesel fuel in common use at the ratio of 20% or 100%. The diesel fuel and blended fuel is irradiated by ultrasonic wave energy. The diese1 fuel, blended fuel, reformed diesel fuel and reformed blended fuel by ultrasonic wave energy are applied to the experimental engine individually. The results are compared with one of the diesel fuel in common use and analyzed.

• 한국자원리싸이클링학회:학술대회논문집
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• 한국자원리싸이클링학회 2005년도 춘계임시총회 및 제25회 학술발표대회
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• pp.109-112
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• 2005

The electrical pulse separation of concrete samples for the recycling purpose has been investigated by the electrical disintegration method using the discharged high voltageimpulse. First, when the consumed energy increased in electrical crushing, fracture section area increased clearly. This result suggests that crushing energy was consumed efficiently. Secondly, when conventional crushing after electrical disintegration is compared with only conventional crushing, gravels are more stable after electrical crushing. Thus, electrical crushing makes it easy to recover gravels from wasted concrete. In the next year, more efficient recovery of gravel for wasted concrete by electrical disintegration will be investigated. Thus, actual wasted concrete crushing by electrical separation and combination of conventional crushing will be carried out.