• Journal of Korean Society of Environmental Engineers
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• v.38 no.8
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• pp.444-451
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• 2016

Most research on membrane fouling models in the past are based on theoretical equations in lab-scale experiments. But these studies are barely suitable for applying on the full-scale spot where there is a sequential process such as filtration, backwash and drain. This study was conducted in submerged membrane system which being on operation auto sequentially and treating wastewater from G-water purification plant in Incheon. TMP had been designated as a fouling indicator in constant flux conditions. Total volume of inflow and SS concentration are independent variables as major operation parameters and time-series analysis and prediction of TMP were conducted. And similarity between simulated values and measured values was assessed. Final prediction model by using genetic algorithm was fully adaptable because simulated values expressed pulse-shape periodicity and increasing trend according to time at the same time. As results of twice validation, correlation coefficients between simulated and measured data were $r^2=0.721$, $r^2=0.928$, respectively. Although this study was conducted limited to data for summer season, the more amount of data, better reliability for prediction model can be obtained. If simulator for short range forecast can be developed and applied, TMP prediction technique will be a great help to energy efficient operation.

• BMB Reports
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• v.39 no.5
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• pp.642-647
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• 2006

Botulinum neurotoxin A (BoNT/A) has been used therapeutically to treat muscular hypercontractions and sudomotor hyperactivity and it has been reported that BoNT/A might have analgesic properties in headache. PEP-1 peptide is a known carrier peptide that delivers fulll-ength native proteins in vitro and in vivo. In this study, a BoNT/A gene were fused with PEP-1 peptide in a bacterial expression vector to produce a genetic in-frame PEP-1-BoNT/A fusion protein. The expressed and purified PEP-1-BoNT/A fusion proteins were efficiently transduced into cells in a time- and dose-dependent manner when added exogenously in a culture medium. In addition, immuno-histochemical analysis revealed that PEP-1-BoNT/A fusion protein efficiently penetrated into the epidermis as well as the dermis of the subcutaneous layer, when sprayed on mice skin. These results suggest that PEP-1-BoNT/A fusion protein provide an efficient strategy for therapeutic delivery in various human diseases related to this protein.

• Journal of Life Science
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• v.30 no.5
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• pp.420-427
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• 2020

A repebody, an artificial non-immunoglobulin protein scaffold, is expected to be a solution in the search for faster, cheaper, and customizable antibodies. However, the production of medical repebodies remains difficult due to their low yield and the complex purification processes required. The Pseudomonas fluorescens ABC transporter system has been suggested as an efficient and cost-effective method for repebody production, but the total yield is low because of the secreted protein's positive charge; thus, a repebody with a high isoelectric point needs to be changed into a more negatively charged protein for better secretion. To achieve this, we first attached oligo-aspartic acids to the N- and C-terminals of the repebody, but secretion efficiency was not enhanced significantly. Subsequently, we devised an alternative method for improved secretion efficiency by engineering fifteen positively charged amino acids to aspartic acid in the non-antigen binding sites of the repebody to give a high net negative charge. As a result, secretion efficiency was greatly enhanced from 21.2% (wildtype) to 58.5% (negatively supercharged). The negatively supercharged repebody was succussfully produced extracellularly by ABC transporter secretion system in P. fluorescens.

• Resources Recycling
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• v.15 no.5 s.73
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• pp.26-32
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• 2006

The waste solution discharged from the LCD manufacturing process contains acids like nitric, acetic and phosphoric acid and metal ions such as Al, Mo and other impurities. It is important to remove impurities less than 1 ppm in phosphoric acid to reuse as an etchant because the residual impurities even in sub-ppm concentration in semiconductor materials play a major role on the electronic properties. In this study, a mixed system of solvent extraction, diffusion dialysis and ion-exchange was developed to commercialize in an efficient system fur recovering the high-purity phosphoric acid. By vacuum evaporation, almost 99% of nitric and acetic acid was removed. And by solvent extraction method with tri-octyl phosphate (TOP) as an extractant, the removal of acetic and nitric acid from the acid mixture was achieved effectively at the ratio A/O=1/3 with 4th stage of extraction stage. About 97.5% of Al and 36.7% of Mo were removed by diffusion dialysis. Essentially almost complete removal of metal ions and purification of high-purity phosphoric acid could be obtained by using ion exchange.

• Applied Chemistry for Engineering
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• v.31 no.5
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• pp.453-466
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• 2020

As the demand for eco-friendly energy increases to overcome the energy shortage and environmental pollution crisis, hydrogen economy has been proposed as a potential solution. Accordingly, an economical and efficient hydrogen production is considered to be an essential industrial process. Research on applying hydrogen separation membranes for H₂/CO₂ separation to the production of highly concentrated hydrogen by purifying H₂ and capturing CO₂ simultaneously from synthetic gas produced by gasification is in progress nowadays. In high temperature environments, the membrane separation process using glassy polymeric membrane with H₂ selectivity has the potential for CO₂ capture performance, and is an energy and cost effective system since polybenzimicazole (PBI)-based separators show excellent chemical and mechanical stability under high-temperature operation conditions. Thus, the development of high-performance PBI hydrogen separators has been rapidly progressing in recent years. This overview focuses on the recent developments of PBI-based membranes including structure modified, cross-linked, blended and carbonized membranes for applications to the industrial hydrogen separation process.

• Journal of the Korean Chemical Society
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• v.50 no.1
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• pp.14-22
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• 2006

the basic model of chemical reactor using glow discharge, we used cathode discharge cell with vacant cavity in the middle. Currently glow discharge is widely studied as a radiation source or atomization device in atomic spectroscopy and remarkable technological achievements are made through the graft with other analysis devices such as microanalysis and steel analysis.1 Additionally, as the characteristics of basic glow discharge and radiation have been reviewed many times, those results could be used in this experiment.2-3 In 1993, an article regarding the treatment of poisonous gas in the air using low temperature plasma was published. According to this article, if DC Glow Discharge is used under continuous atmospheric flow, poisonous gases such as SO2 and NO can be removed.4 Based on those findings, we designed highly efficient reactor where stable air plasma is composed and all air flow pass the negative glow area passing through the tube. It was observed that the cathode tube type glow discharge developed in this study would be economical, easy to use and could be used as radiation source as well.

• Resources Recycling
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• v.26 no.6
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• pp.65-72
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• 2017

APT (Ammonium paratungstate) is widely used in various industries such as metal cutting tools, drill bits, mining tools, and military inorganic materials. In order to produce high purity APT(S), an impurity purification step in an aqueous $Na_2WO_4$ convert $H_2WO_4$ solution is required. It is difficult to remove impurity Na of 200 ppm or less when $H_2WO_4(S)$ is prepared by adding HCl(Aq) to an aqueous solution of $Na_2WO_4$, which is a well-known conventional wet method. However, in this study, a more economical and efficient method of removing Na through electrodialysis using a cationic membrane was studied. A large amount of Na in aqueous solution of $H_2WO_4$ due to $Na_2CO_3(S)$ which was added to dissolve waste tungsten carbide drill and scrap was removed to 20ppm or less through electrodialysis process, and it was confirmed that the effect of Na removal was great when using electrodialysis.

• Journal of the Korean Institute of Gas
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• v.20 no.6
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• pp.23-30
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• 2016

The conventional natural gas engine realized lean combustion for the improved efficiency. However, in order to cope with exhaust gas regulations enforced gradually, the interest has shifted at the stoichiometric mixture combustion system. The stoichiometric mixture combustion method has the advantage of a three-way catalyst utilization whose purification efficiency is high, but the problem of thermal durability and the fuel economy remains as a challenge. Hydrogen-natural gas blend fuel (HCNG) can increase the rate of exhaust gas recirculation (EGR) because the hydrogen increases burning speed and lean flammability limit. The increase in the EGR rate can have a positive impact on heat resistance of the engine due to the decreased combustion temperature, and further can increase the compression ratio for efficient combustion. In this study, to minimize the exhaust emission developed HCNG engine with stoichiometric combustion method, developed three-way catalyst was applied to evaluate the conversion characteristics. The tests were carried out during the steady state and transient operating conditions, and the results were compared for both the conventional and proto-three-way catalyst of HCNG engine for city buses.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2006.05a
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• pp.90-94
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• 2006

The waste solution discharged from the LCD manufacturing process contains acids like nitric, acetic and phosphoric acid and metal ions such as Al, Mo and other impurities. It is important to removal of impurities to tess than 1ppm in phosphoric acid to reuse as an etchant because the residual impurities even in sub-ppm concentration in semiconductor materials play a major role on the electronic properties. In this study, we have been clearly established that a mixed system of solvent extraction, diffusion dialysis and ion-exchange technique, which made individually the most of characteristics is developed to commercialize in an efficient system for recovering the high-purity phosphoric acid. By applying vacuum evaporation, the yield of the process are almost 99% removal of nitric acid and acetic acid was achieved. And by applying the solvent extraction method with tri-octyl phosphate(TOP) as an extractant, the removal of acetic and nitric acid from the acid mixture was achieved effectively at the ratio O/A=1/3 with four stages and the stripping of nitric acid from organic phase is attained at a ration of O/A=1 with six stages by distilled water. About 97% and 76% removal of Al and Mo were achieved by diffusion dialysis. Essentially complete less than 1ppm removal of Al, Mo by using ion exchange ion resin and purification of the phosphoric acid was obtain.

• Resources Recycling
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• v.30 no.1
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• pp.66-76
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• 2021

Electric arc furnace dust (EAFD) contains compounds, such as oxides and chlorides, including large quantities of Zn, Pb and Fe. An efficient and stable method for the extraction of metal elements from EAFD is the Rotary Kiln Process. This method is used to recover Zn in the form of crude ZnO (approximately 60%) via the addition of a reducing agent (coke, anthracite) and limestone (for basicity control) to EAFD. This process is commonly used in industry as well as in research and development. Currently, this method is used in many Korean commercial plants, producing approximately 150,000 tons of Crude ZnO per year. The majority of Zn is found in crude ZnO (approximately 76%). In addition components such as Pb, Cd, Sn, In, Fe, Cl, and F are present as oxides, chlorides, and alkaline compounds. This elements have an adverse effect on the zinc smelting process. Therefore, a refining process that eliminates these impurities is essential. In this study, we developed a process technology that efficiently separates Zn and Pb from byproducts (mainly chlorides). A bag filter was used to collect Zn and Pb generated during the dry purification process of crude ZnO. Pure components were recovered as metals or metal carbonate.