• Composites Research
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• 제35권1호
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• pp.18-22
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• 2022

복합재료의 제조에 있어서 분산은 매우 중요한 요소 중 하나이다. 복합재료의 제조 시 matrix 용재에 강화재를 보다 잘 분산하기 위하여 용매를 사용하는데 용매에 따라 분산도가 달라지기 때문에 어떠한 용매가 분산에 용이할지에 대한 연구가 필요하다. 본 연구에서는 다양한 솔벤트 용매(DMF, NMP, Ethylene glycol, Acetone, DI water)에 대해 나노 필러인 산화 그래핀(Graphene oxide)의 용매에 따른 GO의 분산거동과 용해도 분석을 통해 분산에 유리한 용매를 파악하고자 하였다. 그 결과 UV-Vis spectroscopy 흡광도 측정을 통해 DMF와 Ethylene glycol이 가장 좋은 분산성을 가짐을 알 수 있는 반면 DI water는 가장 낮은 분산성을 보임을 알 수 있었다. 또한 표면장력과 시간에 따른 분산 육안 관측을 통해 DI water, Ethylene glycol, NMP, DMF, Acetone 순으로 분산성이 우수한 것을 알 수 있었는데 이는 Hansen solubility parameter 값과 일치하는 경향임을 확인할 수 있었다.

• Bulletin of the Korean Chemical Society
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• 제35권2호
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• pp.659-662
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• 2014

• Bulletin of the Korean Chemical Society
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• 제16권5호
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• pp.427-432
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• 1995

A model based on two coupled generalized Langevin equations is proposed to investigate the trans-stilbene photoisomerization dynamics. In this model, a system which has two independent coordinates is considered and these two system coordinates are coupled to the same harmonic bath. The direct coupling between the system coordinates is assumed negligible and these two coordinates influence each other through the frictional coupling mediated by solvent molecules. From the Hamiltonian which is equivalent to the coupled generalized Langevin equations, we obtain the transition state theory rate constants of the stilbene photoisomerization. The rates obtained from this model are compared to experimental results in n-alkane solvents.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1999년도 춘계학술발표회요약집
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• pp.398-398
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• 1999

• Archives of Pharmacal Research
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• 제6권1호
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• pp.79-81
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• 1983

Several potent anti-herpes virus nucleosides, 2'fluoro-2'-deoxyarabinofuranosyl pyrimidine nucleosides, were prepared in good yields by a new condensation method using sodium iodide and a new solvent system, and FMAU could be also prepared directly from thymine by this method.

• 대한영양사협회학술지
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• 제4권1호
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• pp.14-19
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• 1998

This study was designed to investigate the role of onion as a natural antioxidant. Onion was distinguished as yellow onion peel and onion flesh. Onion samples were extracted with 5 different kinds of solvents such as water, 70% ethanol, 99.9%ethanol, 99.9% methanol, and 96% butanol in order to select optimal extraction solvents, In this part of study linoleic acid was used s an model system for the purpose of determining the antioxidant activities. The optimal extraction rate of various solvents containing onion samples was determined by measuring extraction yield, electron donating ability(EDA), thiobarbituric acid(TBA), and thiocyanate, which are common methods for measuring activity. As a result 70% ethanol was shown as the most effective solvent.

• 대한화학회지
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• 제45권6호
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• pp.546-548
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• 2001

클로로술폰산을 실리카겔과 반응시키면 실리카겔 표면에 황산이 공유결합으로 고정된 실리카황산을 얻게 된다. 무용매 조건하에서 마이크로웨이브를 쪼여주면서 실리카 황산과 젖은 $SiO_2$를 함께 사용하게 되면 아세탈을 화합물로 변화시키는 효과적인 탈아세탈 시약으로 사용할 수 있다.

• Environmental Engineering Research
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• 제16권1호
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• pp.1-9
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• 2011

During automotive painting, volatile organic compounds (VOCs) associated with the paint solvents are emitted to the atmosphere. Most VOC emissions come from spraying operations via the use of solvent-based paints, as the spraybooth air picks up gaseous solvent compounds and overspray paint materials. The VOCs consist of aromatic and aliphatic hydrocarbons, ketones, esters, alcohols, and glycolethers. Most VOCs (some hydrophilic VOCs are captured and retained in the water.) are captured by an adsorption system and thermally oxidized. In this paper, the processes involved in automotive painting and in VOC control are reviewed. The topics include: painting operations (briefly), the nature of VOCs, VOC-control processes (adsorption, absorption, biological removal, and thermal oxidation) and energy recovery from VOCs using a fuel reformer and a fuel cell, and the beneficial use of paint sludge.

• 한국미생물·생명공학회지
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• 제23권2호
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• pp.229-235
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• 1995

The surface tension-decreasing biosurfactant was purified from Rhodotorula muciloginosa G-1. The purification procedure was the solvent extraction of culture broth. To ensure complete extraction, the sample was extracted twice with equal volume of ethylacetate. The crude solution was washed with n-hexane to remove unconsumed soybean oil. The crude sample of biosurfactant was applied to Silica gel column chromatography equilibrated with chloroform, and eluted with chloroform : methanol gradient. Serveral solvent system was used to developed the thin layer chromatography (TLC). The purified biosurfactant sample gave one spot (Rf 0.78). It was estimated that biosurfactant was glycolipid about having M.W.1,500 with standard of polyethyleneglycol by Sephadex LH-20 column chromatography.

• 멤브레인
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• 제3권3호
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• pp.136-139
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• 1993

It is well known that the membrane permeation in pervaporation is governed by both the chemical nature of the membrane material and the physical structure of the membrane and also the separation can be achieved by differences in either solubility, size or shape. The solubility of the penerrant in the polymeric membrane can be described qualitively by applying the Hildebrand relation [1] which relates the energy of mixing of the penerrant and the polymer material. Froehling et al. have tried to predict the swelling behavior of polymers for the systems of polyvinylchloride(PVC)-toluene-methanol, PVC-trichloroethylene-nitromethane and PVC-n-butylacetate-nitromethane[2]. The former two systems which do not show the donor/acceptor interactions upon mixing showed the successful results[2]. In addition to this technique, there are several other possible approaches to predict the swelling behaviors of polymers, such as the surface thermodynamic approach[3, 4], the comparison of the membrane polarity with the solvent polarity in terms of Dimroth's solvent polarity value[5].