• 전기화학회지
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• 제9권1호
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• pp.29-33
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• 2006

A new porous separator based on poly(vinyl chloride) (PVC)/poly(vinylidene fluoride-co-hexafluoro-propylene) (P(VdF-co-HFP)/poly(methyl methacrylate) (PMMA) was prepared by a phase inversion method. To enhance mechanical property, the membrane was stretched uniaxially at high temperature. Tensile strength and ionic conductivity were measured for various draw ratios. The tensile strength and ionic conductivity were increased with increasing draw ratio. The tensile strength of the separator reached 52MPa after stretching to draw ratio of 5, and the ionic conductivity of the separator was increased from $1.9Xs10^{-4}S/cm\;to\;4.6X10^{-4}S/cm\;at\;25^{\circ}C$. The stretched separator immersed in liquid electrolyte was electrochemically stable up to 4.7 V. The cell based on the stretched separator was maintained at about 99% of the initial discharge capacity after 10th cycle operation at 0.2C rate.

• 멤브레인
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• 제28권4호
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• pp.286-295
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• 2018

폴리에틸렌이민(분자량 800)에 다가이온을 갖는 정삼투용 새로운 유도용질을 합성하고 특성을 분석하였다. 폴리에틸렌이민과 메틸 아크릴레이트의 중화반응으로 중간체를 합성하고, KOH로 가수분해하여 수용성의 카복실산 금속염 형태의 폴리에틸렌이민을 합성하였다. NMR, 점도, 삼투압을 측정하여 유도용질의 특성을 평가하였다. 그 염이 유도용질로서 사용할 수 있는지의 여부를 정삼투 실험을 통하여 알아보았다. 유도용질로서 수투과도와 역염 투과도를 측정하여 NaCl과 비교하였다. 정삼투와 나노여과의 혼성공정을 통하여 유도용질의 회수가능성을 보였다.

• Genomics & Informatics
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• 제9권3호
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• pp.136-137
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• 2011

Methylation of cytosine is a post-synthesis modification that does not affect the primary DNA sequence but greatly influences gene expression level and phenotypes of an organism. As high-throughput sequencing of bisulfite-treated DNA is the most efficient method to identify methylated sites, several tools to map sequencing reads on a reference are available. But tools to visualize and to interpret the methylation level of methylation sites are currently insufficient. Herein, we present a novel tool to visualize the methylation level of CpG sites.

• 한국의류산업학회지
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• 제14권3호
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• pp.472-477
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• 2012

The conditions of wet spinning were considered in order to prepare the fine denier of acrylic fiber. Polyacrylonitrile copolymer was synthesized by the copolymerization of acrylonitrile (AN) and methyl acrylate (MA) initiated by an aqueous sulfite-chlorate redox system. Acrylic fiber was manufactured through wet-spinning in a dimethyl formamide (DMF) system. The conditions of wet-spinning were investigated by i-value, spinning speed, diameter of spinneret, draw ratio, water content of spinning dope and morphology of protofiber. The physical properties of fibers were investigated by Instron. In this experiment, the minimum i-value decreased with the decreasing spinneret diameter, an increased spinning speed, and an increased coagulation bath (CBC) concentration. The maximum draw ratio increased with an increased CBC. The optimum CBC and water content of the spinning dope were 60%-65% and 3.5%, respectively. The tenacity at the breaking point increased with a decreased fineness of fiber. The elongation at breaking point was almost the same value as a function of the fineness of fiber.

• E2M - 전기 전자와 첨단 소재
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• 제10권1호
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• pp.54-60
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• 1997

The electrical and electromagnetic shielding properties have been investigated in polyaniline free standing films with different degrees of elongation cast from N-methyl 2-pyrrolidone(NMP) solution and camphorsulfonic acid(HCSA) doped polyaniline film. The degree of crystallinity of the crosslinked films increased with increasing the draw ratio. For the case of the oriented films doped with hydrochloric acid, we have the values of conductivities up to 173 S/cm. It is considered that the physical micro-crystalline crosslinking domains act as nucleation sites for the increase of relative crystallinity during stretching. We have obtained the value of conductivity 210 S/cm in the HCSA doped polyaniline film cast from the solvent of m-cresol, which is higher than that of the crosslinking oriented films. The electromagnetic shielding efficiency of HCSA doped polyaniline film obtained 37-41 dB in the frequency range of 10MHz-1GHlz, which is higher than that of the crosslinking oriented films. The higher value of electromagnetic shielding efficiency of HCSA doped polyaniline film suggests strong possibility of electromagnetic shielding material.

• 한국대기환경학회지
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• 제23권1호
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• pp.39-49
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• 2007

In this study, the performance characteristics of solid phase microextraction (SPME) were investigated for three major odorous groups that consist of 10 individual compounds ([1] volatile organic compounds (VOC): benzene, toluene, p-xylene and styrene, [2] reduced sulfur compounds (RSC): hydrogen sulfide, methyl mercaptan, dimethylsulfide (DMS), dimethyldisulfide (DMDS), and carbon disulfide, and [3] amine: trimethylamine (TMA)). For the purpose of a comparative analysis, two types of SPME fiber ([1] polidimethylsiloxane/divinilbenzene (P/D) and [2] $Carboxen^{TM}$/polidimethylsiloxane (C/P)) were test ε d against each other for a series of standards prepared at different concentration levels (100, 200, and 500 ppb). To compare the analytical performance of each fiber, all standards were analyzed for the acquisition of calibration data sets for each compound. The results of P/D fiber generally showed that its calibration slope increased as a function of molecular weight across different VOCs; however, those of C/P fiber showed a fairly reversed trend. Besides, we confirmed that the application of SPME is limited to many sulfur compounds; only two compounds (DMS and DMDS) are sensitive enough to draw calibration results out of SPME. The calibration data for RSC show generally enhanced slop values for C/P relative to P/D fiber. However, in the case of TMA, we were not able to find a notable difference in their performance.