• Membrane Journal
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• v.5 no.1
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• pp.1-15
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• 1995

대기오염 문제가 국가적인 사회문제로 대두되면서 대기오염 방지장치의 수요가 급증하고, 점차 강화되는 환경오염 규제로 인하여 고효율의 오염방지장치에서 대표적인 집진장치 기술은 대기 및 실내오염 제어뿐만 아니라, 정확성이 높은 첨단 클리룸 수요의 증가 등으로 인하여 산업체의 각 분야에서 필수적이면서도 기본적인 기술이다. 대기중의 분진은 분자의 응축 및 핵생성 등에 의하여 발생되는 매우 미소한 입자($0.05{mu}{ extrm{m}}$단위)와 일반공장 및 작업장 등에서 발생되는 분진(0.1~$10{mu}{ extrm{m}}$) 그리고 바람에 의한 지표면의 흙, 모래 등에 의한 비교적 큰 분진 등의 광범위한 조성과 입경분포를 가진다. 이 가운데, 특히 산업발달에 따라 불가피하게 생성되며, 대기오염의 주종을 이루면서 인체에 가장 유해한 분진입자는 산업체의 오일 및 석탄연소 보일러, 자동차, 제철/제강 및 시멘트 플랜트 등으로 배출되는 미세입자들이며, 앞으로 이들의 제어에 관한 연구가 지속적인 관심의 대상이 될 것이다.

• Membrane Journal
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• v.7 no.2
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• pp.65-74
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• 1997

Pervaporation pilot tests for obtaining the anhydrous ethanol, which is an automobile fuel additive for reducing air pollution, were carried out in the production field of fermented ethanol by using a PVA composite membrane. In the pervaporation dehydration of the ethanol/water azeotropic mixture, the membrane performance is concluded to be enhanced with the heating temperature of feed. In the determination of the permeate condensation temperature from the viewpoint of energy cost, an Optimal temperature was found to be near $0{\circ}C$. The results on the dehydration of fermented ethanol were similar to those of synthetic ethanol, which indicates that the pervaporation performance is not influenced by impurities contained in the ethanol to be dehydrated. From a comparison of calculated energy needed in the system and measured value in the pilot test, it is confirmed that the latent heat for vaporization of permeant on the permeate side of membrane is supplied from the feed.

• Journal of the Korean Magnetics Society
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• v.27 no.3
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• pp.87-91
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• 2017

Carbon-encapsulated Ni and metal Ni nanoparticles were synthesized by levitational gas condensation (LGC). Methane ($CH_4$) gas was used to coat the surface of the Ni nanoparticles. The Ni particles had a core diameter of 10 nm, and were covered by 2~3 nm thin carbon layers with multi-shells structure.The low magnetization comparing with the Ni nanoparticles without carbon-shell results in the coexistence of nonmagnetic carbon and a large surface spin percentage with disordered magnetization orientation for the nanoparticles. Biginelli reactions in the presence of L-proline and Ni and carbon encapsulated Ni nanoparticles were carried out to change the ratio between stereoisomers. The obtained S-enantiomers for 3,4-dihydropyrimidine (DHPM) using catalysts of Ni, and Ni@C was an excess of about ${\Delta}{\sim}7.4%$ and ${\Delta}{\sim}19.6%$, respectively. The nanopowders were fully recovered using magnet to reuse as a catalyst. The Ni@C was shown at same yield to formation of 3,4-DHPM, though it was recycled for catalyst in the reaction.

• Korean Chemical Engineering Research
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• v.53 no.6
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• pp.730-739
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• 2015

108 microorganism types (79 types of fungi and 29 types of bacteria) were isolated from 25 automobiles generating bad odor when the air conditioner was turned on, and 43 types of fungi and 23 types of bacteria were identified. The analysis of condensate generated by the air conditioners in the automobiles indicated pH 6.4~7.1, 12.5~34.2 mg/L carbon source, 0.9~18.6 mg/L nitrogen source, 0.5~27.8 mg/L ion contents, and 0.1~7.7 mg/L mineral contents. The biofilms were formed by the mesophiles under the summer temperature/humidity condition ($26^{\circ}C$, 70% R.H.), and they were regenerated when the environmental factors (nutritional contents and temperature/humidity) were appropriate even after they were artificially removed. Although the antimicrobials removed 99.9% of planktonic cells within 15 minutes, they were not effective in removing biofilm. Up to 1,950 ppmv of ethanol was observed in the automobile treated with the antimicrobials. Although the figure is lower than the acute toxicity level when inhaled by humans, the health safety of the chemical substances used in the antimicrobials needs to be reviewed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.3
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• pp.343-348
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• 1986

An optical interference method was developed for measuring rapidly growing and evaporating liquid condensate films (e.g., Na$_{2}$SO$_{4}$, $K_{2}$SO$_{4}$) on solid surface exposed to flowing combustion product gases at film thicknesses well below the onset of complications due to run-off. To develop this optical system, this study investigated the optical parameters (e.g., polarization state, incident angle, target roughness, etc.) Trends for the Na$_{2}$SO$_{4}$(l) and $K_{2}$SO$_{4}$(l) deposition rates as a function of target temperature using this optical measuring system agree with the theoretical prediction of the vapor deposition. This study was able to extend the experimental range for vapor plus condensed phase transport and deposition. While previously unable to measure the evaporation rates interferometrically, these rates are estimated from the results of the investigation of polarization states.

• Korean Chemical Engineering Research
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• v.55 no.4
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• pp.478-482
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• 2017

Humidity control of proton exchange membrane fuel cell(PEMFC) is very important control condition during driving. In terms of water management, low humidification conditions are advantageous, and high humidification is advantageous in terms of drainage utilization and energy efficiency. In this study, the characteristics of outlet water in low humidification and high humidification process were studied in terms of utilization of discharged water. Since the impurities in the effluent are generated during the degradation of the membrane and the electrode assembly(MEA), degradation of the MEA under low humidification and high humidification conditions was also studied. The rate of radical generation was high at low humidification condition of the anode RH 0%, which showed that it was the main cause of the degradation of the polymer membrane. Analysis of effluent showed low concentration of fluoride ion concentration of about 20 ppb at high humidification (both electrodes RH 100%) and 0.6 V, which was enough to be used as the feed water for electrolysis. Very low concentration of platinum below 0.2 ppb was detected in the condensate discharged from the high humidification condition.

• Korean Chemical Engineering Research
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• v.52 no.5
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• pp.553-557
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• 2014

Sulfonated polypropylene (S-PP) is prepared by sulfuric acid-acetone aldol condensation reaction of polypropylene (PP) separator to yield hydrophilic separator surface with a moderate amount of $-SO_3H$ groups. Activated carbon supercapacitor is also fabricated adopting the S-PP separator coated with potassium polyacrylate (PAAK) hydrogel polymer electrolyte. As a result, the hydrophilic surface of S-PP separator involves better physical and electrochemical properties such as decrease in contact angle, improvements of wettability, electrolyte uptake, and ionic conductivity to give higher specific capacitance and long cycle-life.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.5
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• pp.473-480
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• 2011

The proton exchange membrane (PEM) fuel cell system is critically dependent on the humidity, which should be properly maintained over the entire operating range. A membrane humidifier is used for the water management in the PEMFC because of the membrane humidifier's reliable performance and zero parasitic power loss. In the PEMFC system, the membrane humidifier is required to provide appropriate humidity for the design point of the fuel cell. Although the performance of the fuel cell depends on the performance of the humidifier, few studies have provided a systematic analysis of the humidifier. We carry out an experimental analysis of the membrane humidifier using a vapor condensation bottle. The dry air pressure, water flow temperature, and air flow rate were chosen as the operating parameters. The results show that the time constant for the dynamic response of the membrane humidifier is relatively short, but additional analysis should be carried out.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.12
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• pp.2125-2134
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• 2000

This research was to develope the economical treatment processes of the landfill leachate to meet the legal discharge standards. To achieve this purpose, experiments were conducted in laboratory to choose the optimum process and to obtain the design factors before a pi!ot-scale test. The concept of the process developing in this research was using the reverse osmosis system. The submerged membrane bio-reactor was used to achieve pre-treatment of reverse osmosis system and the concentrate was treated by evaporator with land fill gas as a fuel. The results of the research showed that SS, $BOD_5$, $COD_{cr}$, $NH_4{^+}-N$ and T-N were removed 99.0%, 43.0%, 12.9%, 48.5% and 18.7% respectively in the submerged membrane bio-reactor. The reverse osmosis system could remove $BOD_5$, $COD_{cr}$, $NH_4{^+}-N$ and T-N as an efficiency of97.5%, 97.6%, 79.7% and 85.4% respectively. The evaporator could remove $COD_{cr}$, $NH_4{^+}-N$ and T-N as an efficiency of 90.5%, 50.6% and 63.3% respectively. However the condensed water of the evaporator was not satisfied the legal standard and should be treated in reverse osmosis with the pre-treated leachate.

• The Korean Journal of Zoology
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• v.35 no.1
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• pp.45-57
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• 1992

생쥐를 48시간 동안 결식시킨 후 유문결찰하여 급성미란을 유발시키고 미란형성부의 점막 내위선을 구성하는 각 세포의 구조변화와 IgA 분비세포의 분포를 관찰하였다. 미란부 점액분포의 변화는 표면상피의 손상 정도가 심해질수록 경계부의 PAS양성반응은 감소되었으며 중심부에서는 표면상피의 소실로 인하여 PAS 양성반응이 관찰되지 않았다. Glycocalyx 관찰을 위한 ruthenium red 반응에서도 경계부의 상피세포 손상이 심해짐에 따라 정단세포막 상층에 나타나는 양성반응은 감소되었고 측면과 기저면의 양성반응은 관찰되지 않은 것으로 보아 세포 손상시 tight junction은 파괴되지 않음을 알 수 있었다. 미란경계부의 미세구조변화로서, 상피세포는 손상이 진행될수록 세포질이 용해되어 공포가 형성되고 핵응축 및 정 단세포질의 점액원과립의 소실이 관찰되었으나 tight junction은 유지되었다. 반면에 점액경세포는 점액원과립의 수가 증가되고 조면소포체가 종창되어 있었다. 미란의 경계부와 중심부에서 벽세포는 다수의 소포가 출현한 후 세포내세관이 종창되었으며 그 후에 mitochondria가 파괴되었고 주세포는 주변의 벽세포가 커지면서 가장자리로 밀려나 크기가 정상보다 작아지고 조면소포체와 mitochondria가 종창을 나타내었다. IgA분비세포는 점막이 파괴된 미란부 점막하조직의 혈관 주변에 다수 존재하는 형질세포에서 확인되었다.