• Bulletin of the Korean Chemical Society
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• 제27권1호
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• pp.71-76
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• 2006

Porous polymer monolithic columns were prepared by the direct free radical copolymerization of methacrylic acid and ethylene glycol dimethacrylate within the confines of a chromatographic column in the presence of toluene-dodecanol as a porogenic solvent. The separation characteristics of the monolithic columns were tested by a homologous series of xanthine derivatives, theophylline and caffeine. The effects of the polymerization mixture composition and polymerization condition, mobile phase composition, flow rate and temperature on the retention times and separation efficiencies were investigated. The results showed that the selection of correct porogenic solvents and appropriate polymerization conditions are crucial for the preparation of the monolithic stationary phases. The separation efficiency was only extremely weakly dependent on flow rate and temperatures. Hydrogen-bonding interaction played an important role in the retention and separation. Compared with conventional particle columns, the monolithic column exhibited good stability, ease of regeneration, high separation efficiency and fast analysis.

• Journal of Pharmaceutical Investigation
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• 제28권1호
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• pp.1-5
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• 1998

The effect of synthetic polymer membranes on the permeation rate of dideoxynucleoside-type anti-HIV drugs through hairless rat skin was studied using ethylene/vinyl acetate copolymer (EVA) and ethylene/methyl acrylate copolymer (EMA) membranes fabricated by solvent casting method. In vitro skin permeation kinetics study of DDC (2',3'-dideoxythymidine), DDI (2',3'-dideoxyinosine) and AZT (3'-azido-3'-deoxythymidine) across the (membrane/skin) composite was conducted for 24 hours at $37^{\circ}C$ using the Valia-Chien skin permeation system. The results showed that skin permeation rate of each drug across the (skin/membrane) composite was mainly dependent on the property of the membrane. Proper selection of the polymeric membrane which resembles hydrophilicity/lipophilicity of the delivering drug was important in controlling the skin permeation rate.

• Bulletin of the Korean Chemical Society
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• 제20권10호
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• pp.1165-1171
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• 1999

The analysis of trace herbicides using the on-line SPE-HPLC system and a photochemical reaction was studied. 18 compounds of herbicides including eight triazines, six phenoxy acids and esters, and four other herbicides were examined. The on-line SPE-HPLC system developed for selection of eluting solvent improved chromatographic efficiency. The recoveries of herbicides were higher than 77%. With 100 mL tap water samples, the detection limits for all analytes were in the 0.1-2.3×10-10 M range. Detection was done by a UV or fluorescence spectrometer after photochemical reaction at the end of the column with 2W or 450W mercury lamp. Without a photochemical reaction, all compounds responded to 230 nm UV detector, but phenoxy acids and esters were weakly detected. However, with a photochemical reaction, these compounds were selectively detected at 320 nm wavelength of UV absorption and 400 nm emission of the fluorescence detectors. This method can be used for the analysis of environmental water containing herbicides at trace levels.

• Applied Biological Chemistry
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• 제33권3호
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• pp.239-246
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• 1990

유기 용매에 추출되는 유리형의 홍국 색소를 보다 많이 얻기 위하여 Monascus anka의 균주를 자연 및 자외선 변이균주에서 선발하고 배양 조건을 탐색하였다. 균주 N3를 Lin's medium에서 진탕 배양, Nishikawa's medium에서 정치 배양 및 진탕 배양하여 균체성장과 색소생성에 소요되는 시간, 유기용매에 추출되는 색소의 양을 비교하여 보았다. Lin's medium에서의 액침 배양에서는 수용성 색소가 우세하게 생성되는 반면 Nishikawa's medium에서의 정치 배양에서는 보다 많은 유기용매 가용성의 색소를 얻을 수 있었다. 한편 탄소원으로는 자당외에 에탄올이 가장 효과적이었다. Sterol 합성저해제를 처리하였을 때는 상당한 색소 형성의 증가를 볼 수 있었다. 이차원 TLC로써 아직 보고된 바 없는 색소들이 존재함을 알 수 있었다. 이 균주의 색소중 가장 다량으로 존재하는 황색소의 하나를 분리하였고 분광학적 방법으로 ankaflavin으로 동정하였다.

• 대한기계학회논문집A
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• 제41권1호
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• pp.41-48
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• 2017

최근 에너지, 바이오공학, 전자공학 등 다양한 분야에서 초미세 고분자섬유의 활용이 증대되고 있다. 이러한 고분자 섬유의 제작방법의 하나로서 전기방사법은 타 공정에 비해 공정장치가 간단하고 재료의 선택에 제한이 적은 등 다양한 장점을 가져 활발하게 사용되고 있다. 그러나 전기방사공정은 미세한 고분자 섬유가 전기장이 부가된 공기층을 통과하면서 높은 불안정성을 가지기 때문에 전기방사공정을 통해 제작되는 섬유매트의 형상 및 기하학적 특성의 조절이 어려운 단점을 가지고 있다. 본 연구에서는 서로 다른 두 가지 용매를 이용하여 섬유의 직경을 나노섬유와 마이크로섬유로 제작할 수 있음을 보였으며, 이를 조합하여 기계적 특성과 공극률을 조절할 수 있는 하이브리드 섬유매트를 제작할 수 있음을 보였다. 또한 제작된 매트를 이용하여 기계적 특성과 공극률이 조절될 수 있음을 확인하였다.

• 대한환경공학회지
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• 제35권11호
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• pp.815-820
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• 2013

본 연구의 목적은 알루미늄판에 활성탄을 얇게 박판으로 코팅하여 분진제거를 위한 활성탄 전극을 제조함에 있다. 전극을 제조하기위하여 알루미늄판에 활성탄을 부착시키기 위한 적정 결합제 선정 그리고 결합제 사용에 따른 활성탄 세공의 막힘방지 그리고 제조된 제극의 분진제거능력 등을 알아보는 연구를 수행하였다. 알루미늄판에 활성탄 부착을 위한 결합제로는 비닐계의 PVA (polyvinyl acetate)가 적정하였고, 결합제 사용에 따른 활성탄 세공의 막힘을 방지하기 위해서는 우선 먼저 활성탄 세공에 결합제의 용매제를 충진하고 나중에 결합제와 활성탄을 혼합 후 고온에서 휘발시키는 방법이 적정하였다. 그리고 활성탄이 코팅된 전극판은 알루미늄 전극판보다 약 두배의 분진부착능력을 보여주었다.

• KSBB Journal
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• 제20권3호
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• pp.183-191
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• 2005

현재 석유화학 및 화학분야에서 이온성 액체를 이용한 많은 연구가 이뤄지고 있다. 휘발성 유기용매의 대체 물질로서 각광을 받고 있는 이온성 액체는 최대 250억불 이상의 시장을 형성할 것으로 기대된다 위에서 말한 바와 같이 생물공학 분야에서도 이온성 액체를 이용한 연구가 시작되어 용매로 사용하는 방법, 분리매개체로서 사용하는 방법 등 다양하게 이용되고 있다. 이러한 이온성 액체는 효소의 활성, 안정성을 증대시킬 뿐 아니라, 분리 과정도 손쉽게 실현할 수 있다. 또한 환경적 측면과, 경제적인 측면을 고려하여 청정용매로 널리 사용 할 수 있을 것이다. 앞에서 말한 바와 같이 생물공학에서 이온성 액체의 응용 가능성은 무한하다 볼 수 있다. 또한, 나노공학과 생물공학을 접목하는 분야에서도 널리 이온성 액체가 쓰일 수 있을 것이다. 유럽과 미국에서는 주로 청정용매로서의 응용에 대한 연구를, 일본에서는 주로 이온 전도성 재료로서의 응용에 대한 연구를 활발히 하고 있다. 이러한 전 세계적인 연구의 활성화에 비하여 국내 상황은 대학 및 연구소에서 산발적으로 연구가 진행되고 있는 수준이다. 이에 국내에서도 이에 대한 관심과 더불어 정부 및 기업체, 대학 및 연구소에 의한 컨소시엄을 형성하여 보다 체계적인 연구지원이 이뤄져야 할 것이다.

• 대한본초학회지
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• 제28권6호
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• pp.47-51
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• 2013

Objectives : The Illicii Veri Fructus was not only traditional medicine but also food in Asia. The aim of this study was selection of optimum solvent in the fruit of Illicii Veri Fructus because an appropriate solvent affect a medicinal effect. Methods : Illicii Veri Fructus was carried out ultrasonic-assisted extraction as various solvents. Two main compounds, p-anisaldehyde and anethole, were successfully analyzed by high performance liquid chromatography-photodiode array detector (HPLC-PDA) and carried out method validation according to ICH guideline. The optimum solvent selected by comparing with yields of two main ingredients. Results : The p-anisaldehyde and anethole were detected at approximately 8.0 min and 19.8 min, respectively. It was all below 5.0% that RSD of retention time and peak area for two main peaks. Calibration curves of two compounds were good linearity as $R^2$ >0.9999. All of the precisions and accuracy were good intra-day and inter-day as below 5.0% RSD. Limited of detection (LOD) of p-anisaldehyde and anethole were analyzed as $0.134{\mu}g/mL$ and $4.286{\mu}g$, respectively. Limited of quantification (LOQ) of two compounds were $0.407{\mu}g$ and $12.989{\mu}g$, respectively. As a result of this study, p-anisladehyde was detected as 0.209 ~ 0.467%, however anethole was not detected in the distilled water. Conclusions : Anethole was main component as 5.329 ~ 6.815% except for water extraction. Methanol extraction among various solvents was detected the highest contents of p-anisaldehyde and anethole as 0.467(${\pm}0.008$)% and 6.815(${\pm}0.220$)%, respectively.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.373-374
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• 2002

Magnetic fluid seals are used in a wide variety of gas and dust sealing applications. However, it is difficult to seal for liquid because of its characteristic. This study will be a basic guide for a magnetic fluid seal for liquid, especially for blood to be practically used in medical instruments such as rotary blood pumps by clarifying its seal properties. Sealing pressure test, durability test, and hemolysis test have been conducted for this seal. In this study, magnetic fluid, sealing fluid, eccentricity ratio, revolution speed were selected as parameters. As results of the tests, it has been found that the properties of magnetic fluid seal depend on the solvent and the saturation magnetization of magnetic fluid. Therefore, the selection of magnetic fluid is important for this seal. It also has been found that eccentricity ratio of the shaft caused harmful effect for seal properties. In conclusion, it has been showed that magnetic fluid seals could be possibly used in medical instruments such as blood pumps when blood come in contact with magnetic fluids.

• 한국의류학회지
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• 제35권4호
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• pp.431-441
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• 2011

Microbial colorants produced from Zooshikella sp. were developed as a reddish dye for fabrics. The reddish colorants were extracted from cell mass of Zooshikella sp. using 100% ethanol and were identified as prodiginine by 1H-NMR and FT-IR analysis. Microbial prodiginine had a maximum spectrophotomatric absorbance at 530nm and were chemically stable and 30 to $60^{\circ}C$. The microbial prodiginine could dye natural fibers such as cotton, silk, and wool as well as synthetic fibers such as nylon. The maximum K/S values of the dyed fiber were shown at 540 run with a color appearance of RP (reddish purple). Silk and nylon had an excellent dyeability among the experimental fibers. The optimum pH for the dyeing of experimental fibers was at pH 3.0 and dyeability was improved as the temperature increased. The cover change of dyed multifiber fabrics with the microbial prodiginine were measured after washing with detergents and a dry cleaning solvent for the selection of a proper fabric against microbial prodiginine. Among the experimental fibers, silk and nylon did not show significant color change after washing. Therefore, under the criteria of dyeability, silk and nylon were excellent fabrics for being dyed by microbial prodiginine.