• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.11
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• pp.977-982
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• 2007

The realization of the photoresist(PR) removal method with vaporized water and ozone gas mixture has been studied for the LCD TFT array manufacturing. The developed PR stripper uses the water boundary layer control method based on the high concentration ozone production technology. We develop the prototype of PR stripper and experiment to find the optimal process parameter condition like as the ozone gas flow/concentration, process reaction time and thin boundary layer formation. As a results, we realize the LCD PR strip rate over the 0.4 ${\mu}m/min$ and this PR removal rate is more than 5 times higher than the conventional immersion type ozonized water process.

• Bulletin of the Korean Chemical Society
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• v.19 no.2
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• pp.218-222
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• 1998

Removal of Cd(Ⅱ), Zn(Ⅱ) and Cu(Ⅱ) from aqueous solutions using the adsorption process on magadiite has been investigated. It was found that the removal percentage of metal cations at equilibrium increases with increasing temperature, and follows the order of Cd(Ⅱ) > Cu(Ⅱ) > Zn(Ⅱ). Equilibrium modeling of adsorption showed that the adsorptions of Cd(Ⅱ), Cu(Ⅱ), and Zn(Ⅱ) were fitted to Langmuir isotherm. Kinetic modeling of the adsorption showed that first order reversible kinetic model fitted to experimental data. From kinetic model and equilibrium data, the overall rate constant (k) and the equilibrium constant (K) for the adsorption process were calculated. The overall rates of adsorption of metal ions follow the order of Cd(Ⅱ) > Cu(Ⅱ) > Zn(Ⅱ). From the results of thermodynamic analysis, standard Gibbs free energy (ΔG°), standard enthalpy (ΔH°), and standard entropy (ΔS°) of adsorption process were calculated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.12
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• pp.6590-6596
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• 2013

Carbon dioxide should be removed to increase the productivity of dimethyl ether(DME) from the DME manufacturing process. In this study, carbon dioxide can be removed using a physical absorbent through a solvent absorption method and membrane separation method. After performing the simulation for the carbon dioxide removal process, the energy consumption of the processes was compared. Methanol was used as a physical absorbent for the rectisol process, dimethyl ethers of polyethylene glycol for the Selexol process and N-methyl pyrrolidone for the Purisol process. By performing the simulation for each process, the energy consumption was compared. The Purisol process had the lowest energy consumption, followed in order by the Selexol process, Rectisol process and Membrane process. Therefore, the Purisol process was the most suitable method for the carbon dioxide process in the DME manufacturing process.

• 한국환경농학회:학술대회논문집
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• 2011.07a
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• pp.223-236
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• 2011

• Journal of Korean Society of Water and Wastewater
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• v.28 no.2
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• pp.195-206
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• 2014

Immobilization of anaerobic ammonium oxidizing bacteria has been studied to enhance the biomass retention of the slowly growing bacteria and the process stability. The purpose of this study was to compare the nitrogen removal efficiency of granular and immobilized anammox bacteria with poly vinyl alcohol and alginate. The specific anammox activity of the granular, homoginized and immobilized anammox bacteria were $0.016{\pm}0.0002gN/gVSS/d$, $0.011{\pm}0.001gN/gVSS/d$ and $0.007{\pm}0.0005gN/gVSS/d$, respectively. Although the activity decreased to 43.7 % of the original one due to low pH and $O_2$ exposure during the homogination and the immobilization, it was rapidly recovered within 7 days in the following continuous culture. When synthetic T-N concentrations of 100, 200, 400, 800 mg/L were fed, the immobilized anammox bacteria showed higher nitrogen removal efficiencies at all operational conditions than those of granular anammox bacteria. When the sludge retention time was shorten below 30.7 days and the reject water was fed, the nitrite removal efficiency of the granular anammox bacteria dropped to 8 % of the initial value, while that of the immobilized anammox bacteria was maintained over 95 % of the initial one. The immobilization with poly vinyl alcohol and alginate would be a feasible method to improve the performance and stability of the anammox process.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.11
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• pp.165-173
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• 2014

This paper presents a fast and high-quality haze removal method by the modification of the conventional transmission estimation process. In the conventional haze removal method, the halo and blocking artifacts arises while estimating the transmission. In order to effectively reduce the artifacts, the proposed method employs the maximum filter after the calculation of the dark channel. Because of the reduction of the artifacts, the proposed method can simplify the transmission refinement process without sacrificing the quality of the results: this paper proposes to use the single-channel guided filter instead of the multi-channel guided filter. The experimental results demonstrate that the quality of the dehazed results by the proposed transmission correction process is improved and the haze removal speed is increased by up to 59.6%, when compared to the conventional ones.

• Journal of Korean Society on Water Environment
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• v.23 no.2
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• pp.206-215
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• 2007

The objective of this study was to establish the optimal system operating strategies for nitrogen and phosphorus removal through model simulation system built for advanced wastewater treatment targeting on simultaneous temporal/special phase isolation BNR process. The simulation system was built with unit process modules using object modules in GPS-X code. The system was well verified by field experiment data. Simulation study was carried out to investigate performance response to design and operation parameters, i.e. hydraulic retention time (HRT), solids retention time (SRT), and cycle time. The process operated at HRTs of 10~15 hours, longer SRTs, and cycle time of 2 hours showed optimal removal of nitrogen. The HRTs of 10~15 hours, SRTs of 20~25 days, and longer cycle time was optimal for phosphorus removal. Both simulation and field studies showed that optimal operating strategies satisfying both the best nitrogen and phosphorus removals include HRTs ranged 10~15 hours, SRTs ranged 20~25 days, and cycle times of 4~8 hours. The simulation system with modularization of generalized components in BNR processes was, therefore, believed to be a powerful tool for establishing optimal strategies of advanced wastewater treatment.

• Journal of Soil and Groundwater Environment
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• v.23 no.6
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• pp.104-113
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• 2018

A three-dimensional electrochemical process using nanosized zero-valent iron (NZVI)/activated carbon (AC) particle electrode and persulfate (PS) was developed for oxidizing pollutants. X-ray diffraction (XRD), scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS), and Brunauer-Emmett-Teller (BET) surface area analysis were performed to characterize particle electrode. XRD and SEM-EDS analysis confirmed that NZVI was impregnated on the surface of AC. Compared with the conventional two-dimensional electrochemical process, the three-dimensional particle electrode process achieved three times higher efficiency in phenol removal. The system with current density of $5mA/cm^2$ exhibited the highest phenol removal efficiency among the systems employing 1, 5, and $10mA/cm^2$. The removal efficiency of phenol increased as the Fe contents in the particle electrode increased. The particle electrode achieved more than 70% of phenol removal until it was reused for three times. The sulfate radical played a predominant role in phenol removal according to the radical scavenging test.

• Journal of Korean Society of Water and Wastewater
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• v.12 no.1
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• pp.102-107
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• 1998

This study was conducted to investigate how the pore sizes of MF and UF membranes affected the removal efficiencies. The experimental results were compared with those obtained from the existing sand filter to select the optimum membrane. Turbidity of the raw water was adjusted to 10, 30, 50, 100, and 200NTU. The removal efficiencies of the turbidity and SS were nearly 100% for all membranes applied. Not membrane differences in the removal efficiencies of dissolved organics were also found. Thus, MF membrane with pore size $0.1{\mu}m$ was selected to obtain satisfactory removal efficiencies of turbidity and bacteria. Permeable flux was also considered. The $0.1{\mu}m$ MF membrane system was operated in the treatment plant to compare the results with those obtained from the existing sand filter. Turbidity, SS, $KMnO_4$ consumption, and number of coliform were chosen to be compared. Because there were not much differencies in the quality of the treated water, the existing coagulation-sedimentation-filtration process might be replaced and upgraded by simpler membrane process.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.1
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• pp.27-34
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• 2006

This study was conducted to evaluate the performance of a membrane bioreactor filled with high concentration of powdered activated carbon (HCPAC-MBR) to reduce DBPs at the drinking water treatment. The pilot system was installed after the rapid sand filtration process whose plant was the conventional treatment process. The removal efficiencies of DBPs were measured during pilot operation period of 2 years. HAA and THM removal rates could be maintained around 80~90% without any troubles and then tremendous reduction of HAA and THM reactivity were observed more than 52%. The average removal rate of HAA formation potential (FP) and THM formation potential (FP) were 70.5% and 67.6% respectively. It is clear that the PAC membrane bioreactor is highly applicable for advanced water treatment to control DBPs.