• Membrane Journal
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• v.14 no.1
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• pp.26-36
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• 2004

Ultrafiltration membranes based on anion charged poly(bis[4-(3-aminophenoxy)phenyl]sulfone pyromellite) imide derivatives (ACPI) were prepared by the phase inversion method. The polymers have good solubility in aprotic polar solvents. The composition of casting solution and the casting conditions played an important role in determining the permeation characteristics of membrane because the membrane structure could be controlled by the preparation conditions. The extent of fouling-repression was observed by the relative ratio of permeate flux ($J_t$)/pure water flux ($J_0$) and the membrane filtration index (MFI). The characteristics were measured by aqueous solution of bovine serum albumin (BSA) over a pH range of 2.5-9.0. The ACPI membrane having a hydrophilic property was less fouled than the membrane prepared from the original polyimide. With increasing the ion exchange capacity of ACPI membrane, th $\varepsilon$ relative ratio of flux was higher while the membrane filtration index was lower as compared with the original polyimide membrane. From the further away from isoelectric point of bovin serum albumin, the permeation was higher as well as the formation of fouling was more diminish. ACPI membranes having various their properties could be obtained. Further, it was proved that their permeation properties could be determined from the preparation conditions, various operating conditions, and dim $\varepsilon$ rent ion exchange capacity of anion charged polyimide derivatives.

• Proceedings of the Membrane Society of Korea Conference
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• 2004.05b
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• pp.153-155
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• 2004

상전이법으로 제조된 비대칭막은 세공의 크기를 nm이하의 수준으로 줄여 주면 막 여과저항이 크게 증가하여 경제성이 떨어지는 문제점을 가지고 있다. 이에 대한 대안으로 복합막이 제조되어 사용되고 있는데, 복합막은 우수한 투과도와 높은 배제율을 달성하기 위한 적극적인 대안이 되고 있다. 정수처리 및 수질환경 분야에 사용되는 나노복합막의 경제성을 더욱 향상시키기 위해서는 나노막의 투과유속을 증가시켜야 하는데, 복합막의 투과 성능은 지지체의 특성과 스킨층을 형성시키는 기술에 의해 좌우된다.(중략)

• Proceedings of the Membrane Society of Korea Conference
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• 1997.04b
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• pp.30-31
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• 1997

기체분리용 막에서 높은 투과성능을 얻기 위해서는 다공성 지지체 표면에 얇은 skin layer를 갖는 막을 제조하는 것이 가장 중요하다. 이 skin layer는 결함이 없고 가능한 한 얇아야 고선택도를 유지하면서 투과도를 높일 수 있다. 이러한 skin layer를 갖는 비대칭막을 wet phase inversion method를 이용하여 제조하는 연구를 하였다. 본 연구에서는 wet phase inversion method를 이용하여 표면에 skin layer를 갖는 polyimide 비대칭 평막을 제조하는데 있어서 제막조건에 따른 막 구조 조정과 투과특성을 평가하고자 하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.11a
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• pp.597-598
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• 2023

X-ray는 촬영 방식의 한계로 진단하기 어려운, 품질 낮은 영상을 다수 발생시킨다. 이러한 저품질 영상은 임상 현장에서의 진단이 어려울 뿐만 아니라, 진단 보조 도구를 개발함에 모델의 성능과 신뢰도를 떨어뜨리는 주요 요소가 된다. 특히 투과도가 낮은 영상은 학습 성능에 악영향을 미친다는 것이 입증된 바 있다. 따라서 본 연구는 투과도가 낮은 영상을 진단에 부적합한 영상으로 정의하여, 이를 분류하는 기법을 제안한다. 제안하는 기법은 민감도 94.9%. 특이도 96.0%의 높은 성능을 보였다.

• Proceedings of the Membrane Society of Korea Conference
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• 1999.10b
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• pp.77-80
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• 1999

• Proceedings of the Membrane Society of Korea Conference
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• 1999.04a
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• pp.61-62
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• 1999

• Membrane Journal
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• v.16 no.2
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• pp.115-122
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• 2006

In this study the membrane preparation and water vapor permeation of the hydrophilic polymer materials, polyaminosiloxane and polyhydroxylsiloxane, used as the coating materials for the preparation of asymmetric flat and hollow fiber membranes were investigated. And the water vapor permeation towards air permeation and their permselectivity were intensively studied for the resulting Resin A/Resin C (coupling agent) and Resin B/Resin C membranes. The water vapor permeability for 3 wt% Resin C introduced into Resin A (Resin A/Resin C) membrane was higher than for 1 and 5 wt% membranes and also water vapor permeability increased with increasing operating temperatures. In addition, at this content of 3 wt% Resin C, the absorption capability became maximum through dynamic equilibrium absorption experiment. Water vapor permeability, 43578 Barrer (1 Barrer = $10^{-10}cm^3(STP){\cdot}cm/cm^2{\cdot}s{\cdot}cmHg$) and 53000 Barrer, and the selectivity of $P(H_2O)P(Air)$, 101.3 and 102.6 were shown at 25 and $35^{\circ}C$, respectively.

• Membrane Journal
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• v.29 no.6
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• pp.348-354
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• 2019

Recently, the application range of organic solvent nanofiltration (OSN) technology has been expanding, requiring membranes with better performance. In this work, thin film composite (TFC) OSN membrane was fabricated. First, ultrafiltration support membrane was prepared via nonsolvent-induced phase separation (NIPS) technique using polysulfone (PSf) and polyethersulfone (PES). Then, the effect of pore forming additives such as polyvinylpyrrolidone (PVP) and pluronic F-127 were employed to improve the membrane permeance. The well-known interfacial polymerization technique was employed using MPD-TMC chemistry to form a thin film on top of the fabricated support, and its solvent permeance and nanofiltration performance was characterized. It was found that polyethersulfone support exhibited more reliable performance compared to polysulfone, and PVP additive was more effective compared to Pluronic F-127. As for the oSN performance, polar aprotic solvents like acetonitrile show significantly higher flux (986.5 L·m^-2·h^-1·bar^-1) compared to water and EtOH (9.5 L·m^-2·h^-1·bar^-1).

• Membrane Journal
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• v.14 no.1
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• pp.75-84
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• 2004

In this study, we present a noble study far membrane transport models using chlorine resistance of polyamide RO membranes. Membrane transport mechanism is investigated by the comparison of membrane permeation performance under the continuous and Intermittent operation modes with mixed feed solution containing NaOCl and NaCl. Analysis of permeation performance indicates that solution-diffusion model and preferential adsorption-capillary flow model are relatively efficient according to operation mode. Under the continuous flow state, mass transfer depends on preferential adsorption-capillary flow model rather than solution-diffusion model. On the other hand, it prefers solution-diffusion model to preferential adsorption-capillary flow model under the stationary state. SEM images of NaOCl treated membrane surfaces strongly support these conclusions. These surface images reveal that NaOCl treated membrane in continuous operation mode exhibits ridge and valley structure in some fraction of the surface area, whereas that in intermittent operation mode shows surface degradation entirely.

• Membrane Journal
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• v.14 no.3
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• pp.207-217
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• 2004

In this study, we prepared nanofiltration membrane by applying the interfacial polymerization method as a way of manufacturing composite membranes. We have examined the effects of various preparation factors such as monomer concentration and composition, thermal curing condition, post treatment condition. In addition to preparation conditions, we also monitored the effects of operation conditions such as feed solution concentration and operation pressure on the permeation properties of the resulting nanofiltration membrane. We intended to increase the permeation rate of nanofiltration membrane by the enlargement of effective surface area using additives during interfacial polymerization step. With increasing the monomer concentration, membrane permeation rate are decreased with maintaining almost constant rejection. With respect to curing condition, with increasing the curing temperature both permeation rate and rejection are decreased. With increasing the ratio of MPD in amino monomer composition, permeation rate decreased drastically with high rejection. With increasing the feed solution concentration, both permeation rate and rejection decreased. Both permeation rates and rejection increased with increasing the operating pressure. Nanofiltration membrane have higher surface roughness with increasing additive concentration in the case of using MPD contained amine composition than using piperazine alone. Permeation rates are much lower than the nanofiltration membrane prepared by piperazine.