• 한국세라믹학회지
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• 제37권1호
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• pp.26-32
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• 2000

Preparation and characteristics of a matrix retaining electrolyte using SiC whisker, PES binder, and NMP(n-methyl-2-pyrrolidone) as a non-volatile solvent for a phosphoric acid fuel cell were investigated. The conditions of binder and plasticizer, and the effects of substituting a volatile solvent by a non-volatile solvent were also studied. The minimum amount of the binder was about 17 wt% for the proper bubble pressure and surrounding SiC whiskers. And the maximum amount of the plasticizer was about 10wt% to be fitted into the polymer chain of the binder. The matrix prepared by using a non-volatile solvent needed longer time to dry, and its pore size was smaller compared with that of the matrix prepared by using volatile solvent. The small pore size resulted in decrease of the overall pore volume. The ionic conductivity in the condition of the same thickness was decreased due to decrease of phosphoric acid absorbancy. As the internal resistance of the electrolyte increased, the fuel cell performance slightly decreased.

• 공업화학
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• 제24권2호
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• pp.171-176
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• 2013

지구온난화 문제가 대두되면서 volatile organic compound (VOC) free 도료의 필요성이 크게 증가하고 있다. 현재 국내외적으로 사용되고 있는 도료의 약 70~80% 정도가 용매형 도료이다. 따라서 지구온난화 문제의 근본적인 해결을 위해서는 도료의 희석제로 사용되고 있는 용매인 휘발성 유기화합물(VOCs)의 배출을 최소화 할 수 있는 무용제형도료의 개발이 필수적이다. 본 연구에서는 무용제도료를 개발하기 위하여 기존의 페놀수지의 특성인 산성화로 인해 도료로 사용 시 부착성이 떨어지는 단점을 보완하기 위해 아크릴계 단량체들을 첨가하였다. 합성한 페놀수지와 PF/PMMA 블렌드 수지와 PF/PHEMA 블렌드 수지의 구조분석결과 블렌드된 형태를 확인하였고 접착인장강도실험을 통해 PF/PMMA 블렌드 수지가 2.818 Mpa의 값으로 도료시스템에 적용 가능성을 확인하였다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제8권1호
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• pp.46-50
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• 2008

The effect of physicochemical properties of solvents on the microstructure of polyvinyl carbazole (PVK) film for non-volatile polymer memory was investigated. For the solubilization of PVK molecules and the preparation of PVK films, four solvents with different physicochemical properties of the Hildebrand solubility parameter and vapor pressure were considered: chloroform, tetrahydrofuran (THF), 1,1,2,2-tetrachloroethane (TCE), and N,N-dimehtylformamide (DMF). The solubility of PVK molecules in the solvents was observed by ultravioletvisible spectroscopy. PVK molecules were observed to be more soluble in chloroform, with a low Hildebrand solubility parameter, than solvents with higher values. The aggregated size and micro-/nano-topographical properties of PVK films were characterized using optical and atomic force microscopes. The PVK film cast from chloroform exhibited enhanced surface roughness compared to that from TCE and DMF. It was also confirmed that the microstructure of PVK film has an effect on the performance of non-volatile polymer memory.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.320-320
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• 2010

The dye-sensitized solar cells (DSSCs) have achieved so far the highest validated efficiency over 11%. However, the cells with the best performance utilize volatile solvent as a electrolyte, which can cause some practical limitations for the long-term operation. This is one of the most substantial problems to be resolved for the commercialization of DSSCs. In order to improve the long-term stability, many research groups have reported new electrolyte system, to replace the liquid type electrolyte by non-volatile ones. In this work, we studied long-term stability of the DSSCs with various types of electrolytes such as (PVDF HFP) based polymer, eutectic melts of ionic liquids, and liquid based solvent. The cells with various electrolytes have been exposed to the condition under thermal stress and illumination over 1000 hours. We will report the change of photovoltaic properties with time and investigate the degradation mechanism with the impedance spectroscopic analysis.

• 분석과학
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• 제33권1호
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• pp.11-22
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• 2020

When extracting semi-volatile components of herbal medicines using hot water vapor, some substances may react with water vapor or oxygen, and some volatile substances may be lost, when using an organic solvent extraction method has the disadvantage that it may contain a non-volatile material and residual organic solvent. In addition, it is inefficient to separate semi-volatile substances from herbal medicines into each single component and conduct biological activity research for each component to determine the effective ingredient, and some components may be lost in the separation process. In this study, semi-volatile substances evaporated under two pressure-reduced conditions in Chinese herbal medicines such as Cnidii Rhizoma, Aucklandiae Radix and Amomum Fructus were separated by cooling with liquid nitrogen. Those were analyzed by gas chromatography-mass spectrometry (GC-MS) to identify the components, and this method may be used to study biological activities at the cellular level. The substances separated under reduced pressure, essential oil obtained by simultaneous distillation extraction (SDE) method and substances by using solid phase micro-extraction (SPME) from Cnidii Rhizoma, Aucklandiae Radix and Amomum Fructus were analyzed by GC-MS. In the case of Cnidii Rhizoma and Aucklandiae Radix, there were some differences among the essential oil components obtained by SDE and those identified by low temperature capture (CT) and SPME method, these were believed to be produced by some volatiles reacting with water or oxygen at the boiling point temperature of water.

• 한국연초학회지
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• 제7권1호
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• pp.85-92
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• 1985

Extraction efficienties of volatile organic acids in tobacco leaves according to several extraction methods were investigated and contents of volatile organic acids in 16 kinds of tobacco leaf varieties were compared. Extraction efficiency according to simultaneous distillation and extraction was 5 to 10 times higher than that according to solvent extraction, steam distillation, essential oil extraction or continuous extraction and distillation. Total contents of volatile organic acids were 1.62 to 12.94mg per l00g of sample in aromatic tobacco varieties,0.12 to 2.08mg in flue-cured tobacco leaves, and trace in burleys. Among the Korean aromatic tobacco varieties, total contents of volatile organic acids in ST374-3 were the highest, 4.66mg per l00g of sample, and those in Sohyang and Hyangcho were low, 1.69mg and 1.62mg, respectively. Among flue-cured tobacco varieties, those in NC2326 were the highest, 2.08mg per 100g of sample, but those in the other varieties were not more than 0.80mg per 1 00g of sample. Total contents of volatile organic acids in acidic hydrolysis with 0.1 M tartaric acid were higher than in non-acidic condition in all kinds of tobacco varieties.

• 한국환경과학회지
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• 제21권2호
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• pp.165-179
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• 2012

Indirect $CO_2$ effect due to non-methane volatile organic compound (NMVOC) emissions from solvent and product use and fugitive NMVOC emissions from fuels in the Republic of Korea and 13 Annex I countries under United Nations Framework on Climate Change were estimated and the proportions of them to total greenhouse gas (GHG) emissions ranged from 0.092% to 0.45% in 2006. Indirect greenhouse effect ($CO_2$, $CH_4$, and $O_3$) were estimated at 13 photochemical assessment monitoring sites in the Republic of Korea using concentrations of 8 NMVOCs of which indirect global warming potential (GWP) were available. The contribution of toluene to mixing ratio was highest at 11 sites and however, the contribution of toluene to indirect greenhouse effect was highest at nine sites. In contrast to toluene, the contributions of ethane, butane, and ethylene were enhanced. The indirect greenhouse effects of ethane and propane, of which ozone formation potentials are the lowest and the third lowest respectively among targeted 10 NMVOCs, ranked first and fourth highest respectively. Acetaldehyde has relatively higher maximum incremental reactivity and is classified as probable human carcinogen however, its indirect GWP ranked second lowest.

• 청정기술
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• 제22권3호
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• pp.203-207
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• 2016

Here, we report a novel fabrication technique for patchable organic lasing sheet based on non-volatile liquid organic semiconductors and freestanding polymeric film with high flexibility and patchability. For this work, we have fabricated the second-order DFB grating structure, which leads to surface emission, embedded in the freestanding polymeric film. Using an ultra-violet (UV) curable polyurethaneacrylate (PUA) mixture, the periodic DFB grating structure can be easily prepared on the freestanding polymeric film via a simple UV curing process. Due to unsaturated acrylate remained in the PUA mixture after UV curing, the freestanding PUA film provides adhesive properties, which enable mounting of the patchable organic lasing sheet onto non-flat surfaces with conformal contact. To achieve laser actions in the freestanding resonator structure, a composite material of liquid 9-(2-ethylhexyl)carbazole (EHCz) and organic laser dyes was used as the laser medium. Since the degraded active materials can be easily refreshed by a simple injection of the liquid composite, such a non-volatile liquid organic semiconducting medium has degradation-free and recyclable characteristics in addition to other strong advantages including tunable optoelectronic responses, solvent-free processing, and ultimate mechanical flexibility and uniformity. Lasing properties of the patchable organic lasing sheet were also investigated after mounting onto non-flat surfaces, showing a mechanical tunability of laser emission under variable surface curvature. It is anticipated that these results will be applied to the development of various patchable optoelectronic applications for light-emitting displays, sensors and data communications.

• KSBB Journal
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• 제17권2호
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• pp.148-152
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• 2002

초임계 이산화탄소를 이용한 유자과피로 부터의 휘발성 정유성분의 추출은 entrainer를 사용하지 않을 경우 압력 13.8㎫, 온도 4$0^{\circ}C$에서 756.61mg/sample 30g이 추출되었으며 entrainer를 7.4mL/min을 첨가하였을 경우 압력이 13.8㎫, 온도 4$0^{\circ}C$에서 5416.64mg/sample 30 g이 추출되어 약 7배의 추출량의 증가를 볼 수 있었다. 이는 보조용매를 첨가함으로서 초임계 이산화탄소의 유자과피의 휘발성 정유성분에 대한 용해력을 증가시키는데 큰 영향을 미치는 것으로 알 수 있다.

• Korean Chemical Engineering Research
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• 제55권2호
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• pp.214-219
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• 2017

본 연구에서는 블록공중합체의 자기조립(Self-assembly) 성질과 상전이를 통한 비대칭의 다공성 구조를 형성하는 NIPS 기술을 결합한 SNIPS (Self-assembly and non-solvent induced phase separation) 공정을 이용하여 PS-b-P4VP 블록공중합체 분리막을 제조하였다. 기존의 연구는 단순히 원하는 구조 구현에만 집중되었고 SNIPS 공정상의 내재 변수(농도, 증발시간, 용매의 조성, 습도)들에 대한 체계적인 연구는 보고되지 않았다. 본 연구에서는 PS-b-P4VP 와 DMF, 1,4-Dioxane, THF, DI를 이용해 내재 변수의 영향을 정성적으로 분석하였다. 그 결과, 용액의 농도와 휘발성 용매의 비율이 적당하고 습도가 낮은 환경에서 모폴로지가 최적화 되었으며, PS-b-P4VP 분리막은 표면에 잘 구현된 실린더 구조가 형성되었고 75%의 높은 기공도와 약 18%의 표면 기공도를 가지는 것을 확인하였다.