• Journal of environmental and Sanitary engineering
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• v.16 no.1
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• pp.34-39
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• 2001

Submerged Membrane Bio-Reacter(SMBR) process was used to food wastewater treatment. From laboratory pilot-scale experiment data, it was confirmed that this process was very effective process for organics, suspended solid, and N, P treatment. It was found that BOD and COD removal rate were obtained 90% and 92%, respectively, for 150 days operation. Organics loading rate did not affect to the removal efficiency because MLSS concentration in aerobic tank was highly maintained. IN the case of first reactor operated with anoxic and second reactor operated as aerobic, T-N, T-P removal rate were obtained 93% and 95%, respectively. It was shown that removal efficiency could be maintained stable due to the complete removal of SS and sludge production decreased with increasing of sludge retention time.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.478-478
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• 2013

Resistance-change Random Access Memory (ReRAM) memory, which utilizes electrochemical control of metal in thin films of solid electrolyte, shows great promise as a future solid state memory. The technology utilizes the electrochemical formation and removal of metallic pathways in thin films of solid electrolyte. Key attributes are low voltage and current operation, excellent scalability, and a simple fabrication sequence. In this work, we investigated the nature of thin films formed by photo doping of Ag+ ions into chalcogenide materials for use in solid electrolyte of Resistance-change RAM devices and switching characteristics.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.369-372
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• 2008

An experimental study is carried out to study two-phase vertically upward hydraulic transport of solid particles by water in a vertical and inclined (0${\sim}$60 degree) concentric annulus with rotation of the inner cylinder. Rheology of particulate suspensions in shear-thinning fluids is of importance in many applications such as particle removal from surfaces, transport of proppants in fractured reservoir and cleaning of drilling holes, and so on. Annular fluid velocities varied from 0.2 m/s to 1.5 m/s for the actual drilling operational condition. Macroscopic behavior of solid particles, averaged flow rate, and particle rising velocity are observed. Main parameters considered in this study were radius ratio, inner-pipe rotary speed, fluid flow regime, and particle injection rate. For both water and CMC solutions, the higher the concentration of the solid particles is, the larger the pressure gradients become

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.413-414
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• 2012

Programmable Metallization Cell (PMC) memory, which utilizes electrochemical control of nanoscale quantities of metal in thin films of solid electrolyte, shows great promise as a future solid state memory. The technology utilizes the electrochemical formation and removal of metallic pathways in thin films of solid electrolyte. Key attributes are low voltage and current operation, excellent scalability, and a simple fabrication sequence. In this study, we investigated the nature of thin films formed by photo doping of Ag+ ions into chalcogenide materials for use in solid electrolyte of programmable metallization cell devices. We measured the I-V characteristics by field-effect of the device. The results imply that a Ag-rich phase separates owing to the reaction of Ag with free atoms from chalcogenide materials.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.3
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• pp.182-186
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• 2012

Resistance-change Random Access Memory(ReRAM) memory, which utilizes electrochemical control of metal in thin films of solid electrolyte, shows great promise as a future solid state memory. The technology utilizes the electrochemical formation and removal of metallic pathways in thin films of solid electrolyte. Key attributes are low voltage and current operation, excellent scalability, and a simple fabrication sequence. In this work, we investigated the nature of thin films formed by photo doping of $Ag^+$ ions into chalcogenide materials for use in solid electrolyte of Resistance-change RAM devices and switching characteristics according to field-effect.

• 연구논문집
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• s.30
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• pp.67-77
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• 2000

This study was performed to investigate the characteristics and performance of model Decanter for separating swine wastewater to solid and liquid which is slurry state with 12.6% TS. Swine wastewater of the slurry tank was pumped into model Decanter which capacity was $2m^3$/hr in 10% TS Slurry inside of bowl was separated to solid-liquid by centrifugal acceleration. Sampling was done in the section of slurry feed pipe, supernatant outflow pipe, cake discharge pipe. After solid-liquid separation TS, $COD_cr$ and slurry volume reduction effect represented 38%, 40%, 19.6% respectively. Relation factor of model Decanter operation slurry concentration, optimum retention time of slurry, overflow velocity of supernatant, supernatant concentration, sludge removal rate etc. Optimal operation conditions can be set and evaluated efficiency based on the experimental results in the case of Decanter adopted for solid-liquid separation in highly concentrated swine wastewater.

• Environmental Engineering Research
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• v.10 no.4
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• pp.155-164
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• 2005

This study investigated the possibility of reducing the residual aluminum (Al) in the treated water using polymers. Two raw waters (lake and river water) and three kinds of polymers (coagulant, flocculant, and filtration aids) were used for this purpose. This study found that coagulation at the high dose did not necessarily lead to the high concentration of the residual Al in the treated water. The coagulation efficacy was found more important in determining the residual Al than the coagulant dose. The use of a polymer enhanced the removal of turbidity as well as the residual Al. The coagulant aid removed the dissolved Al as well as the particulate Al by helping the coagulation and the solid-liquid separation. The flocculant aid and the filtration aid preferentially removed the particulate Al while helping the solid-liquid separation. The filtration aid reduced the residual Al substantially more effectively than the flocculant aid. The polyamine-based coagulant aid (FL) showed the better performance in reducing the residual Al and turbidity than DADMAC (WT). The cationic flocculant aid with weak charge density and the medium molecular weight (SC-020) showed the best performance in reducing the residual Al.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.869-872
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• 2003

This paper presents a geometric machining simulation algorithm to enhance the reliability and user-friendliness of a comprehensive computer aided process planning (CAPP) system by verifying generated NC data. In order to represent the complex machining geometry with high accuracy, the proposed algorithm is developed based on a boundary representative (B-rep) solid modelling kernel. Solid models are used to represent the part geometry. tool swept volume and material removal volume by Boolean unite and subtract operations. By integrating a machining simulation procedure into the CAPP system, the systematic analysis of the tool path can be implemented synthetically. To demonstrate and check the validity of suggested system, a simple example of simulation is represented and the result is discussed.

• Journal of the Korean Society of Safety
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• v.11 no.3
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• pp.112-118
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• 1996

When fossil fuels are burned they produce CO gas because of incomplete combustion. If the CO gas reacts with the hemoglobin in the red blood cells, it may result in death or sequelae. Generally, the CO gas is eliminated in the form of the $$$CO_2$ gas by the oxidation reaction over the platinum catalyst. In this study, the electrochemical CO removal was investgated by using the solid electrolyte cell reactor, the type of which was represented as reactants$/Pt/Y_2O_3-ZrO_2/Pt/Air$. If the overpotential was applied to the platinum working electrode, the conversion could be changed with the overpotential applied. It was found that the oxidation rate could be increased 2.8 times higher than that of the normal condition, i. e. under open circuit conditions when $P_{co}/P_{O_2}$ was 0.5 and overpotential was 0.9V. From these results, it is concluded that the reactor used in this study is more efficient than conventional catalytic reactors.

• Journal of Environmental Science International
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• v.19 no.9
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• pp.1119-1127
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• 2010

The behavior of copper throughout the whole process of wastewater treatment plant that uses the activated sludge process to treat the wastewater of petrochemical industry that contains low concentration of copper was investigated. Total inflow rate of wastewater that flows into the aeration tank was $697\;m^3$/day with 0.369 mg/L of copper concentration, that is, total copper influx was 257.2 g/day. The ranges of copper concentrations of the influent to the aeration tank and effluent from the one were 0.315 ~ 0.398 mg/L and 0.159 ~ 0.192 mg/L, respectively. The average removal rate of copper in the aeration tank was 50.8 %. The bioconcentration factor (BCF) of copper by microbes in the aeration tank was 3,320. The accumulated removal rate of copper throughout the activated sludge process was 71.3%, showing a high removal ratio by physical and chemical reactions in addition to biosorption by microbes. The concentration of copper in the solid dehydrated by filter press ranged from 74.8 mg/kg to 77.2 mg/kg and the concentration of copper by elution test of waste was 2.690 ~ 2.920 mg/L. It was judged that the copper concentration in dehydrated solid by bioconcentration could be managed with the control of that in the influent.