• 생태와환경
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• 제38권spc호
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• pp.58-61
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• 2005

Environmental polluting materials from road surface drainage are a significant nonpoint source influenced to the eutrophication of lake and ecosystems with a transport development in recent years. To elucidate the discharge characteristics, the changing patterns in concentrations of polluting materials such as suspended solid (SS), chemical oxygen demand (COD), nitrogenous and phosphorus nutrients in drainage waters, were investigated during rainfall. Load variation of COD concentration in drainage water samples was closely related to that of SS concentration. This indicates that SS contained a greater part of organic matter. A quite difference between the past pavement and the new well-drainage pavement system was observed in the concentrations of SS and COD in drainage waters. Appreciable concentrations of nitrite and nitrate were determined in drainage waters. The present results indicate that the drainage water from road surfaces is a significant nonpoint source, and that the well-drainage pavement system introduced to skid prevention has an effect on the decreases of pollutants.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2005년도 총회 및 춘계학술발표회
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• pp.352-358
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• 2005

This study aims to separate hydrograph into baseflow and event water to calculate baseflow rate during a rainfall in small catchments, Yuseong, Daejeon, The hydrograph of stream during a period with no excess rainfall will decay. The discharge is composed entirely of groundwater contributions. During the period, the Cl concentration of the stream water can be regarded as being in equilibrium with that of the groundwater. Using Cl as a conservative tracer, two-component hydrograph separations were performed from end point of the period to next end point. The required data were obtained by monitoring of the surface water table, along with discharge rate of stream. Cl concentration of rainfall, surface water were measured and recorded. Hydrograph separation, a mixing model using chemical tracer is applied to chemical hydrograph separation technique. These results show that baseflow rates are 31.6% of rainfall in the catchments during study period.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1999년도 추계학술발표회
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• pp.34-38
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• 1999

This paper investigated remediation options for contaminated sediments with heavy metals. Twenty three sediment samples were taken from three different depths of 0.5m, 1.5m and 2.5m. The concentration of Heavy metals Cu, Pb, and Hg were measured. The concentration of copper far exceeded the Sediment Quality Guideline in U.S.A and Interim Sediment Quality Guidelines in Canada. Therefore, remediation of the sediments is requried to protect the benthos. Two remediation options were suggested : dredging of the organic sediments as deep as about 85cm followed by surface covers with clean soil, and in-situ stabilization of tile sediments using lime or cement followed by surface cover with clean soil.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.603-603
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• 2012

최근에 전면 emitter의 doping profile이 다른 selective emitter solar cell은 실제 제작시단파장 영역에서 많은 gain을 얻을 수 없어 LBC 구조의 태양전지에 관한 연구가 많이 진행되고 있다. 본 연구는 TCAD simulation을 이용하여 후면에 형성되는 locally doped BSF(p++) region의 doping profile의 변화에 따른 태양전지 특성에 관한 연구이다. Al으로 형성되는 local back contact의 doping depth 및 surface concentration에 따른 전기적, 광학적 분석을 통해 주도적인 인자를 분석하고 최적화하였다. 특히 doping depth에 따른 변화보다는 surface concentration의 변화에 따른 특성변화가 주도적으로 나타났다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2018년도 춘계학술대회 논문집
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• pp.57-57
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• 2018

Zinc-oxide (ZnO), II-VI semiconductor with a wide and direct band gap (Eg: 3.2~3.4 eV), is one of the most potential candidates to substitute for ITO due to its excellent chemical, thermal stability, specific electrical and optoelectronic property. However, the electrical resistivity of un-doped ZnO is not low enough for the practical applications. Therefore, a number of doped ZnO films have been extensively studied for improving the electrical conductivities. In this study, Ti-doped ZnO films were successfully prepared by atomic layer deposition (ALD) techniques. ALD technique was adopted to careful control of Ti doping concentration in ZnO films and to show its feasible application for 3D nanostructured TCO layers. Here, the structural, optical and electrical properties of the Ti-doped ZnO depending on the Ti doping concentration were systematically presented. Also, we presented 3D nanostructured Ti-doped ZnO layer by combining ALD and nanotemplate processes.

• 한국염색가공학회지
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• 제13권1호
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• pp.9-17
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• 2001

The purpose of this study is to present basic data for the enzymatic modification of acetate fabrics. The weight loss and rate of weight loss of acetate fabrics increased with increasing NaOH concentration and treating time. Acetyl value decreased as the weight loss became higher. The weight loss of alkaline-treated acetate fabrics were directly proportional to the concentration and treating time of cellulase. The optimum temperature and pH in cellulase treatment were $55^\circ{C}$ and pH 3.5. The surface shape revealed that density of fiber decreased by alkaline-treatment. With the treating time of cellulase, fibrillation occurred. In case of higher weight loss in alkaline treatment, fibril is removed after 180 min. The tensile strength decreased by alkaline and cellulase treatment. Especially, in case of higher weight loss of alkaline treatment, tensile strength decreased suddenly. Alkaline treatment increased the drapability of acetates, while cellulase treatment increased it initially but decreased gradually with treatment time. The dyeability after alkaline treatment was improved for reactive dye, but deteriorated for disperse dye. The cellulase treatment of acetate lowered the dyeability for both types of dyes.

• 한국전기전자재료학회논문지
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• 제15권2호
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• pp.169-172
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• 2002

The voltage holding ratio(VHR) and the residual DC property in the in-plane switching (IPS) cells on a polyimide surface was studied. Several IPS cells which have different concentrations of cyano liquid crystals (LCs) were fabricated. We found that the VHR of the IPS cell was decreased with increasing concentration of cyano LCs. Also, the VHR of the IPS cell was increased with increasing specific resistivity of fluorine LCs. The residual DC voltage of the IPS cell by capacitance-voltage (C-V) hysteresis method was decreased with increasing concentration of cyano LCs. The residual DC property of the IPS cell on the rubbed PI surface can be improved by high polarity of cyano LC.

• 한국분무공학회지
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• 제8권2호
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• pp.31-37
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• 2003

Polymeric fibers with nanometer-scale diameters are produced by electrospinning method. When the electrical forces at the surface of a polymer solution or melt overcome the surface tension, then electrospinning occurs and nanofibers are made. Polyethylene oxide(PEO) have been electrospun in our laboratory Electrospun PEO fibers are observed by scanning electron microscopy or transmission electron microscopy In thl:; study. the average diameter of the electrospun fibers decreases with decreasing PEO concentration and increasing electric field strength. The optimal conditions for producing uniform PEO 100nm fibers are the 10wt% PEO concentration at a voltage 25 to 30kV and a distance of 10cm from tip to collector.

• 대한화학회지
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• 제62권2호
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• pp.79-86
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• 2018

This study reported the adsorption of Cu(II) ions onto activated carbon prepared from Myristica Fragrans shell (MFS AC) over independent variables of contact time, activating chemical (NaOH) concentration, initial adsorbate concentration, initial pH of adsorbate solution and adsorption temperature. The MFS AC structure, morphology and total surface area were characterized by FTIR, SEM and BET techniques, respectively. The Cu(II) ions adsorption on the MFS AC (activated using 0.5 M NaOH) fitted best to Freundlich adsorption isotherm (FAI), and the FAI constant obtained was 0.845 L/g at $30^{\circ}C$ and pH 4.5. It followed the pseudo first order of adsorption kinetic (PFOAK) model, and the PFOAK based adsorption capacity was 107.65 mg/g. Thermodynamic study confirmed the Cu(II) ions adsorption should be exothermic and non-spontaneous process, physical adsorption should be taken place. The total surface area and pore volume based on BET analysis was $99.85m^2/g$ and 0.086 cc/g, respectively.

• 대한화학회지
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• 제58권1호
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• pp.85-91
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• 2014

The corrosion behavior of aluminum and mild steel in hydrochloric acid medium was studied using a nicotinic acid hydrazide as inhibitor by potentiodynamic polarization, electrochemical impedance spectroscopy technique and gravimetric methods. The effects of inhibitor concentration and temperature were investigated. The experimental results suggested, nicotinic acid hydrazide is a good corrosion inhibitor for both aluminum and mild steel in hydrochloric acid medium and the inhibition efficiency increased with increase in the inhibitor concentration. The polarization studies revealed that nicotinic acid hydrazide exhibits mixed type of inhibition. The inhibition was assumed to occur via adsorption of the inhibitor molecules on the aluminum and mild steel surface and inhibits corrosion by blocking the reaction sites on the surface of aluminum.