• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.571-571
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• 2013

본 연구에서는 유연 유기태양전지용 플렉시블 InZnSnO (IZTO)/PEDOT:PSS 투명전극을 제작하고 그 특성을 연구하였다. 이를 위해 선형 대향 타겟 스퍼터(Linear Facing Target Sputtering: LFTS) 시스템을 이용하여 그라비아 프린팅된 PEDOT:PSS/PET 매우 얇은 IZTO 투명전극을 성막하였다. 일반적으로 PEDOT:PSS 전극은 수분/산소에 약하지만 매우 얇은 IZTO passivation 층을 코팅함으로써 PEDOT:PSS의 안정성을 향상시키는 동시에 전기적 특성을 향상시킬 수 있다. 이러한 PEDOT:PSS 기반 하이브리드 투명 전극을 제작하기 위해 IZTO 두께를 5 nm에서 40 nm 까지 조절하여 IZTO/PEDOT:PSS 다층 투명전극을 제작하였으며, 이때 IZTO 두께 변수에 따라 제작된 하이브리드 IZTO/PEDOT:PSS 투명전극의 전기적, 광학적 특성을 분석하였다. 최적화된 20 nm의 IZTO의 두께에서 IZTO/PEDOT:PSS 하이브리드 투명전극은 PEDOT:PSS 단일층으로 제작된 플렉서블 투명전극과 동일한 우수한 유연성을 가짐과 동시에 PEDOT:PSS 단일층보다 현저히 낮은 면저항 값(353.6 ohm/sq.)과 높은 광투과율(83.09%)을 나타내었다. 최적화된 IZTO/PEDOT:PSS 투명전극으로부터 제작된 플렉서블 유기태양전지는 IZTO의 passivation 특성으로 인해 PEDOT:PSS 단일막을 이용하여 제작된 플렉시블 투명전극보다 우수한 소자효율을(FF: 59.04%, Voc: 0.588 V, Jsc: 7.554 mA/cm2, PCE: 2.622%) 나타내었다. 이러한 결과들은 LFTS 공법으로 PEDOT:PSS위에 성막된 IZTO passivation 층이 PEDOT:PSS의 특성을 향상시킬 뿐만 아니라, PEDOT:PSS의 안정성도 향상시킬 수 있기 때문에 기존 PEDOT:PSS 기반 투명 전극의 문제점을 해결할 수 있는 해결책으로 적용이 가능하다.

• Journal of the Korean Geotechnical Society
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• v.16 no.4
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• pp.31-42
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• 2000

In this study, the stability of group piles installed in deep sea to the seaquake was studied by performing the calibration chamber model tests for open-ended pipe piles, grouted piles under soil plug and close-ended piles installed in the simulated deep sea. For each case (a single pile, 2-pile and 4-pile groups), series of seaquake tests were performed. While, during the simulated seaquake, the compressive capacity of the single open-ended pile depended on pile penetration depth(=7m), were found to be stable. But, a single grouted pile with penetration depth of 13m kept "mobility" state, the one with penetration depth of 20m was stable and grouted pile groups with penetration depth of 7m were stable regardless of pile penetration depth. By grouting soil plug of open-ended piles and soil under the pile toe of open-ended pipe piles installed in the deep sea, failure of soil plugging was prevented. Thus, close-ended piles were more stable than open-ended pile against the seaquake motionake motion.

• The Korean Journal of Zoology
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• v.32 no.2
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• pp.142-152
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• 1989

We have produced a new monoclonal antibody detecting common acute lymphoblastic leukemia antigen (CALLA) and designated as KP-22. CALIA detected by KP-22 is expressed on the all of the various cefl lines examined including common ALL. Burkitt's lymphoma, human fibroblasts and cultured normal human fibroblasts. However out of cell lines tested, a fraction of J-ALL and all of myelocytic leukemia and all other nonleukemia cell lines except for fibroblast are CALIA negative. Immunoprecipitation of solubilized 125 I-labeled membrane proteins from cultured human fibroblasts and leukemia cell lines with KP-22 revealed a major polypeptide chain with an apparent molecular weight of approximately 100 Kd and 95 Kd, respectively. Even though a microheterogeneity in terms of molecular weight between two CALLAs, the peptide mapping patterns of them &e identical indicating that such a microheterogeneity seems to be partly due to heterogeneous terminal sialic acid compositions added by a posttranslational modification process.

• Membrane Journal
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• v.28 no.4
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• pp.221-232
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• 2018

The silica containing carbon ($C-SiO_2$) membranes were fabricated using poly(imide siloxane)(Si-PI) and polyvinylpyrrolidone (PVP) blended polymer. The characteristics of porous carbon structures prepared by the pyrolysis of polymer blends were related with the micro-phase separation behaviors of the two polymers. The glass transition temperatures ($T_g$) of the mixed polymer blends of Si-PI and PVP were observed with a single $T_g$ using differential scanning calorimetry. Furthermore, the nitrogen adsorption isotherms of the $C-SiO_2$ membranes were investigated to define the characteristics of porous carbon structures. The $C-SiO_2$ membranes derived from Si-PI/PVP showed the type IV isotherm and possessed the hysteresis loop, which was associated with the mesoporous carbon structures. For the molecular sieving probe, the $C-SiO_2$ membranes were prepared with the ratio of Si-PI/PVP and the pyrolysis conditions, such as the pyrolysis temperature and the isothermal times. Consequently, the $C-SiO_2$ membranes prepared by the pyrolysis of Si-PI/PVP at $550^{\circ}C$ with the isothermal time of 120 min showed the $O_2$ permeability of 820 Barrer ($1{\times}10^{-10}cm^3(STP)cm/cm^2{\cdot}s{\cdot}cmHg$) and $O_2/N_2$ selectivity of 14.

• Membrane Journal
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• v.27 no.6
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• pp.499-505
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• 2017

The increasing number of natural disasters resulting from anthropogenic greenhouse gas emissions has prompted the development of a gas separation membrane. Carbon dioxide ($CO_2$) is the main cause of global warming. Organic polymeric membranes with inherent flexibility are good candidates for use in gas separation membranes and poly(dimethyl siloxane)(PDMS) specifically is a promising material due to its inherently high $CO_2$ diffusivity. In addition, poly(vinyl pyrrolidine)(PVP) is a polymer with high $CO_2$ solubility that could be incorporated into a gas separation membrane. In this study, poly(dimethyl siloxane)-poly(vinyl pyrrolidine)(PDMS-PVP) comb copolymers with different compositions were synthesized under mild conditions via a simple one step free radical polymerization. The copolymerization of PDMS and PVP was characterized by FTIR. The morphology and thermal behavior of the produced polymers were characterized by transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Composite membranes composed of PDMS-PVP on a microporous polysulfone substrate layer were prepared and their $CO_2$ separation properties were subsequently studied. The $CO_2$ permeance and $CO_2/N_2$ selectivity through the PDMS-PVP composite membrane reached 140.6 GPU and 12.0, respectively.

• Membrane Journal
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• v.23 no.5
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• pp.352-359
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• 2013

In the present study, $CO_2$ permeation through a hydrophilic NaY zeolite membrane was studied under permeate evacuation mode for $CO_2$ single gas, $CO_2-N_2$ and $CO_2-O_2$ binary mixtures, and $CO_2-N_2-O_2$ ternary mixture. It was reconfirmed that the $CO_2$ permeation was governed by surface diffusion and the $CO_2$ selectivity was induced from blocking effect of adsorbed $CO_2$ molecules. The $CO_2$ permeance measured in permeate evacuation mode was much lower than that done in He sweeping mode, but was comparable to that obtained under feed pressurization mode. The NaY zeolite membrane showed a considerable $CO_2$ separation for $14%CO_2-80%N_2-6%O_2$ mixture : $CO_2$ permeance was about $1{\times}10^{-7}mol/m^2secPa$ and $CO_2$ selectivity was more than 10. Therefore, it was concluded that NaY zeolite membrane was one of promising membranes for post-combustion CCS process.

• Membrane Journal
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• v.33 no.6
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• pp.447-453
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• 2023

The performance of computer systems and the development of various computer simulation programs have made it possible to analyze chemical systems composed of more complex elements, and accordingly, research using molecular dynamics simulation is being actively conducted. Research on calculating the gas permeation characteristics of polymer membranes by molecular dynamics, which was previously conducted mainly through experiments, is receiving attention for gas barrier membranes used in food packaging and pharmaceuticals. Recently, there has been a report that a gas barrier effect appears when a coating film is made using silk fibroin, and in this study, a study was conducted using molecular dynamics simulation to confirm whether an oxygen barrier effect appears when a composite film is made using silk fibroin. We built a single model, calculated the gas permeation characteristics, and compared it with the experimental value to confirm that the model reflects the actual experimental results. Actual composite membrane models were then built and the gas movement path within the polymer was analyzed. As a result, oxygen molecules were found that they could not pass through and was blocked in the fibroin region. Therefore, the composite membrane with silk fibroin has excellent oxygen barrier property and is expected to be useful in food packaging, etc.

• Membrane Journal
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• v.28 no.6
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• pp.432-443
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• 2018

In this study, propylene/propane separation behavior of Na-type faujasite zeolite membranes is predicted by observing gravimetric adsorptions of propylene and propane on zeolite 13X. The gravimetric adsorptions were measured by using a magnetic suspension balance (MSB) at temperatures of 323, 343, 363 K and a pressure range of 0.02-1 bar. The pressure was increased at 0.1 bar intervals. As adsorption temperature increased, adsorptions of propylene and propane decreased and propylene/propane adsorption selectivity increased. Also, the diffusion coefficients of propylene and propane were increased as the adsorption temperature increased, following the Arrhenius equation. The maximum propylene/propane diffusion selectivity was 0.9753 at 323 K. The perm-selectivity was calculated from the adsorption data of zeolite 13X and compared with the perm-selectivity measured in the single gas permeation experiment for the Na-type faujasite zeolite membrane. The maximum values for the calculated and measured perm-selectivities were observed at a temperature of 323 K. It could be concluded that the prediction of propylene/propane separation of surface diffusion-based membrane by using gravimetric adsorption data is reasonable. Therefore, it is expected that this prediction method can be applied to the screening of adsorption-based microporous membrane for propylene/propane separation.

• The korean journal of orthodontics
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• v.30 no.2 s.79
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• pp.197-204
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• 2000

[$K^+$]-selective ion channels were studied in excised inside-out membrane patches from human osteoblast-like cells (G292). Three classes of $K^+$channels were present and could be distinguished on the basis of conductance. Conductances were $270\pm27\;pS,\;113\pm12\;pS,\;48\pm8\;pS$ according to their approximate conductances in symmetrical 140 mM KCl saline at holding potential of -80 mV It was found that the small conductance (48 pS) $K^+$channel activation was dependent on membrane voltage. In current-voltage relationship, small conductance $K^+$channel showed outward rectification, and it was activated by the positive potential inside the membrane. In recordings, single channel currents were activayed by a negative pressure outside the membrane. The membrane pressure increased $P_{open}$ of the $K^+$ channel in a pressure-dependent manner. In the excised-patch clamp recordings, G292 osteoblast-like cells have been shown to contain three types of $K^+$ channels. Only the small conductance (48 pS) $K^+$channel is sensitive to the membrane stretch. These findings suggest that a hyperpolarizing current, mediated in part by this channel, may be associated with early events during the mechanical loading of the osteoblast. In G292 osteoblast-like cells, $K^+$channel is sensitive to membrane tension, and may represent a unique adaptation of the bone cell membrane to mechanical stress.

• Membrane Journal
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• v.23 no.4
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• pp.278-282
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• 2013

Zeolitic imidazolate frameworks (ZIFs) have been the focus of interest for their physical and chemical properties, especially, for their extraordinary gas separation properties. In this study, a novel and efficient method for the fabrication of continuous ZIF-7 film on ${\alpha}$-alumina substrate has been investigated. The electrospray deposition method was tried for the first time to prepare ZIF films directly without the necessity of prior substrate seeding. It has the advantage of depositing thin ZIF-7 films directly on the ${\alpha}$-alumina substrate by electrospraying the precursor solution. The ZIF-7 films have been characterized through XRD, FE-SEM, and single gas permeation tests.