• Journal of Plant Biology
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• 제33권2호
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• pp.135-140
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• 1990

The membrane potential in the subepidermal cells of Lemna gibba G3 fronds was measured in the dark with glass capillary microelectrodes. At pH 7, the membrane potential, approximately-215 mV, could be depolarized to -82∼-88 mV by 0.1 mM dicyclohexylcarbodiimide (DCCD) or by KCN at 0.3 mM or higher concentrations. When the pH of the medium was altered the potential showed reversible changes, while it revealed no response to the external pH changes when energy transduction across the membrane was being blocked by 0.1 mM DCCD. The results support an assumption that the active component of the membrane potential of Lemna subepidermal cells is generated by electrogenic H+ -pump. By the addition of 0.10∼5.00 mM salicylic acid(SA) to the bathing medium the membrane potential was depolarized to a great extent, and the removal of SA from the medium repolarized the potential showing almost complete recovery, 92.3∼97.6% to the initial levels. Although the potential was greatly depolarized by 5.0% or higher concentrations of dimethylsulfoxide (DMSO), the recovery rate by DMSO removal was decreased as the pretreatment concentration had increased. Twenty percent DMSO pretreatment limited the recovery at only 47.1%. The presence of SA in the bathing medium could reversibly increase the permeability of the plasmalemma. DMSO at its concentration of 5.0% or higher increased the permeability of the membrane by irrevesibly impairing the membrane component involved in the membrane permeability.

• Bulletin of the Korean Chemical Society
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• 제34권10호
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• pp.2973-2977
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• 2013

In this study, we developed a liquid crystal (LC)-based optical sensor for monitoring enzymatic activity through orientational changes in liquid crystals (LCs) coupled to the properties of a poly-${\small{L}}$-lysine (PLL)-based polymeric membrane. We prepared a PLL-based polymeric membrane at the planar interface between the thermotropic liquid crystal and aqueous phases. The PLL-based polymeric membrane was obtained by contacting the PLL solution with water immiscible LCs, 4-cyano-4'-pentyl-biphenyl (5CB) doped with adipoyl chloride. We then investigated the membrane properties by examining the permeability of the membrane to phospholipids, 1,2-didodecanoyl-rac-glycero-3-phosphocholine (DLPC). The permeability of the membrane to transport phospholipids was monitored through the orientational transition of 5CB in contact with the dispersions of DLPC. Since trypsin can enzymatically catalyze the hydrolysis of PLL, we incubated an aqueous trypsin solution with the membrane for 2 h at room temperature to cause an increase in the permeability of the polymeric membrane to DLPC. As a result, a bright to dark optical shift of LCs was observed, which implied that an enzymatic reaction between trypsin and PLL-based membrane occurred. Two control experiments using chymotrypsin and bovine serum albumin (BSA) revealed no sign of improved permeability based on the orientational transition of LCs.

• 센서학회지
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• 제21권3호
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• pp.229-234
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• 2012

The existing permeability measurements based on pressure differential between the polymer membrane that is permeable to measure the amount of oxygen used, but these methods must be kept in a vacuum, and the measurement of the membrane with low permeability in the membrane is too time consuming. In recent years by using electrochemical method polymer membrane currents caused by the amount of oxygen is a measure of how much is used. In this study, apparatus consisting of one anode and six cathodes for multi-oxygen permeability tester used the same number of membranes produced by electrochemical oxygen permeation characteristics. In this study, one silver/silver chloride anode electrochemical method with a hexagonal sensor to put various kinds of polymer membranes with the six oxygen permeability for simultaneous measurement in real-time systems. Six cathodes (Pt), and one of the coil-shaped anode (Ag/AgCl) to form a hexagonal one of the polarographic oxygen sensor in a single measurement system by six sensors. Each sensor for making hexagonal specificity of the sensor to compensate for the conditions obtained in a pure nitrogen gas and pure oxygen gas conditions. With this study, self-developed hexagonal sensor capable of measuring sensors and oxygen permeability tester, for a multi-six different oxygen permeability characteristics of the membrane measured at the same time.

• 한국식품저장유통학회지
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• 제5권1호
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• pp.35-39
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• 1998

The cell membrane properties in relation to flesh browning of Fuyu persimmon fruits during CA storage were studied. Compared to intact fruits, the flesh tissue of browned fruits showed higher rate of electrolyte leakage, indicating incresed membrane permeability. It could be assumed that the increased membrane permeability results in 1eakage of phenolic compounds from vacuole and their oxidation by contacting with PPO, inducing finally the development of flesh browning. In addition, lower content of fatty acids and higher saturation rate of them were found in browned fruits. In conculusion, it was suggested that the inhibited fatty acid metabolism and fatty acid saturation during CA storage cause membrane Permeability to increase.

• 한국소음진동공학회논문집
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• 제17권4호
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• pp.342-349
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• 2007

Following the 2002 World-Cup held in Korea, studies have been actively conducted on plans to utilize all-weather stadiums of fine figures, where large-scale spaces are available for various utilizations. In Japan, dome-type stadiums have been built and are utilizing across the whole nation not only for sports events but also variety of other large-scale events. PTFE(poly tetra fluoro ethylene) is one of the membrane material mainly used for the outer ceiling surface of membrane structures. However, there has not been enough research on the acoustical properties of PTFE membrane material which has been widely used in the multi-purpose stadiums. In this study, air permeability values and sound absorption coefficient of PTFE membrane materials were measured and evaluated in the gymnasium. From the results of measurements of sound absorption coefficient and air permeability of inner membrane materials, it was found that the sound absorption coefficient was good in the air permeability range of $5{\sim}15\;cc/cm^2/s$. Also the relation ship between air permeability and sound absorption coefficient was very high and the sound absorption coefficient was the highest in the range of $6{\sim}9\;cc/cm^2/s$. Secondly, an analysis on the measurements sound absorption characteristics of inner membrane material reveals that the overall sound absorption coefficient was stabilized(higher than 0.5 throughout the whole frequency bands) when the air space behind the membrane material was deeper than 600 mm. When PTFE sound absorptive membrane material was installed in the ceiling of gymnasium, it was confirmed that sound absorptive membrane material can reduce reverberation and increase speech intelligibility in the gymnasium.

• 환경위생공학
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• 제13권2호
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• pp.147-155
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• 1998

In this study, we prepared non-porous plasma membrane for having high permeability and selectivity and this membrane was deposited on the $Al_{2}O_{3}$ membrane by using $CHF_{3}$ & $SiH_{4}$ monomer. Also, we investigated for the permeation characteristics of the plasma polymer membrane by Ar plasma treatment. When the position of substrate was near cathode, the selectivity was increased with Ar plasma treatment time and rf-power. The pore size of $Al_{2}O_{3}$ membrane had an effect on the permeability and the position of substrate affected selectivity.

• Elastomers and Composites
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• 제33권1호
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• pp.37-43
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• 1998

The permeation of gas through polymer membrane at temperatures above its glass transition, generally occurs by a solution-diffusion mechanism. This mechanism is performed by the affinity difference between polymeric materials and gas molecules, and various technologies, such as copolymerization, impregnation and so on, have been researched to improve the affinity of polymeric material for the gases. In this study, permeability and selectivity for some gases were obtained from steady-state rates of gas permeation through silicone rubber membrane which is prepared by supercritical fluid extraction method. The permeability was measured by the volumetric method proposed by Barrer. Permeability was increased generally with temperature and permeation pressure. Silicone rubber membrane shows a higher permeability to $CO_2$ than to $O_2$, $N_2$. This results probably reflect the relatively high solubility of CO_2 in silicone rubber membrane, which is due to the affinity of $CO_2$ molecules. Since separation powers of $CO_2/N_2$, $CO_2/O_2$ were more than 200, and 100, respectively, it is able to separate $CO_2$ from the air, and the optimum temperature and pres-sure was 328.15 K, 60 cmHg respectively. In future, it is possible that the silicone rubber membrane can be used for separation or concentration of $CO_2$ through experiment for mixed gas separation.

• The Plant Pathology Journal
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• 제19권4호
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• pp.189-194
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• 2003

The effects of prochloraz on membrane permeability and germination of uredospores of Puccinia recondita were investigated to determine its potential mode of action on wheat leaf rust control activity. Disease control activity of ergosterol biosynthesis inhibitors (EBIs) and their activities on uredospore membrane permeability and germination were examined with wheat leaf rust pathogen, both in vitro and in vivo. While wheat leaf rust was not controlled by prochloraz, electrolytic leakage and spore germination of P. recondita uredospore was the highest with the use of prochloraz among the eight fungicides tested. Prochloraz stimulated uredospore of P. recondita to germinate at a higher ratio. Although certain EBIs, such as hexaconazole, showed excellent control activity, their effects on uredospore membrane permeability and germination was much inferior to prochloraz. Therefore, results of this study suggest that effects of EBIs on membrane permeability and germination of uredospore are not always correlated with their disease control activity.

• KSBB Journal
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• 제19권1호
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• pp.62-66
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• 2004

의료용 갈바닉형 산소센서를 이용하여 BOPP, OPP 및 CPP 막의 두께와 온도 변화에 따른 산소 투과 특성을 연구한 결과, 전류와 산소농도의 탁월한 선형관계 (R＞0.999)로부터 구한 산소 투과도는 BOPP ＞ OPP ＞ CPP의 순으로 막의 두께에 의존하는 것으로 나타났다. 본 전기화학적 산소투과도 측정방법은 기존의 압력법에 비하여 간편한 실험방법임을 확인하였다 한편, 산소 투과도에 대한 활성화에너지는 13.1 kJ/mol에서 28.5 kJ/mol 사이의 값으로, 각 막에 따라 다른 값을 나타냈지만 같은 종류의 막에서 두께에 의존하지는 않았다. 이는 고분자의 활성화 에너지는 고분자가 갖고 있는 고유의 물성에 의존하기 때문인 것으로 추정된다.

• 상하수도학회지
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• 제27권3호
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• pp.363-371
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• 2013

In this study, effect of activated carbon size on flux and fouling of membrane was investigated on activated carbon and membrane hybrid system. The activated carbon was prepared with crushing and screening. The activated carbon was named by A100, B100, A200, B200, A325 and B325 due to size of activated carbon. The permeability for A100, B100, A200 and B200 showed no significant difference. However, the permeability for A325 and B325 was decreased rapidly and was lowed due to increase the concentration of NOM. Main resistance for A100, B100, A200 and B200 was identified as irreversible fouling. However main resistance for A325 and B325 was identified as reversible fouling. The smaller activated carbon adsorbs NOM faster than bigger particles, which can show high permeability at early stage of the operation and then showed faster decrease of permeability at end of the operation.