• Applied Chemistry for Engineering
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• v.26 no.4
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• pp.400-405
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• 2015

Traditional anti-reflective (AR) coating films prepared using tetraethylorthosilicate (TEOS) as a precursor absorbs water easily in addition to having a weak abrasion resistance. To improve the transmittance, hydrophobicity and abrasion resistance of AR coating film, various AR coating films were prepared using methyltrimethoxysilane (MTMS) as a precursor in addition to introducing a fluoroalkylsilane, acid catalyst, base catalyst and acid-base two step catalyst. The prepared AR coating films were then characterized by UV-Vis spectroscopy, contact angle analyzer, atomic force microscope (AFM), pencil scratch hardness test and cross-cut test. As a result, the transmittance of bare glass was 90.5%, while that of AR coating glass increased to 94.8% at curing temperature of $300^{\circ}C$. When the fluoroalkylsilane was added, the water contact angle of AR coating film increased from $96.3^{\circ}$ to $108^{\circ}$, indicating that the hydrophobicity of the film was greatly improved. The abrasion resistance of AR coating film was also improved by the acid catalyst, whereas the transmittance increased by the base catalyst. In the case of AR coating film prepared using an acid-base two step catalyzed reaction, both the transmittance and abrasion resistance of the film was synergistically enhanced as compared with those of AR coating films prepared without introduction of a catalyst.

• Polymer(Korea)
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• v.34 no.6
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• pp.540-546
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• 2010

In this manuscript, in order to reduce methanol permeability and, at the same time, to increase proton conductivity THS-PSA containing silica compound, responsible for methanol permeability reduction, and sulfonic acid, responsible for proton conductivity enhancement, was applied onto PVA/PSSA-MA membranes. And in order to improve durability, the resulting membranes, PVA/PSSAMA/THS-PSA, were exposed to 500ppm F2 gas at varying reaction times. The surface-fluorinated membranes were characterized through the measurement of contact angles, thermo-gravimetric analysis, and X-ray photoelectron spectroscopy to observe the physico-chemical changes. For the evaluation of the electro-chemical changes in the resulting membranes, its water contents, ion exchange capacity, proton conductivity, and methanol permeability were measured and then compared with the commercial membrane, Nafion 115. Finally, the membran electrode assembly(MEA) was prepared and the cell voltage against the current density was measured. As fluorination time increased, the contents of F2 increased up to maximum 4.3% and to depth of 50 nm. At 60 min of fluorination, the proton conductivity was 0.036 S/cm, larger than Nafion 115 at 0.024 S/cm, and the methanol permeability was $9.26E-08cm^2/s$, less than Nafion 115 at $1.17E-06cm^2/s$.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.2
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• pp.149-157
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• 2005

PFC(Perfluorocarbon) decontamination process is one of best methods to remove hot particulate adhered at inside surface of hot cell and surface of equipment in hot cell. It was necessary to develop a particulate filtration equipment to reuse PFC solution used on PFC decontamination due to its high cost and to minimize the volume of second wastewater. Contamination characteristics of hot particulate were investigated and then a filtration process was presented to remove hot particulate in PFC solution generated through PFC decontamination process. The removal efficiency of PVDF(Poly vinylidene fluoride), PP(Polypropylene), Ceramic(Al$_{2}$O$_{3}$ filter showed more than 95$\%$. The removal efficiency of PVDF filter was a little lower than those of other kiters at same pressure(3psi). A ceramic filter showed a higher removal efficiency with other filters, while a little lower flux rate than other filters. Due to inorganic composition, a ceramic filter was highly stable against radio nuclides in comparison with PVDF and PP membrane, which generate H$_{2}$ gas in e-radioactivity atmosphere. Therefore, the adoption of ceramic filter is estimated to be suitable for the real nitration process.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.7
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• pp.9-15
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• 2018

The turbochargers, which are used widely in diesel and gasoline engines, are an effective device to reduce fuel consumption and emissions. On the other hand, turbo-lag is one of the main problems of a turbocharger. Bearing friction losses is a major cause of turbo lag and is particularly intense in the lower speed range of the engine. Current turbochargers are mostly equipped with floating bearings: two journal bearings and one thrust bearing. This study focused on the bearing friction at the lower speed range and the experimental equipment was established with a drive-motor, load-cell, magnetic coupling, and oil control system. Finally, the friction losses of turbochargers were measured considering the influence of the rotating speed from 30,000rpm to 90,000rpm, oil temperature from $50^{\circ}C$ to $100^{\circ}C$, and oil supply pressure of 3bar and 4bar. The friction power losses were increased exponentially to 1.6 when the turbocharger speed was increased. Friction torques decreased with increasing oil temperature and increased with increasing oil pressure. Therefore, the oil temperature and pressure must be maintained at appropriate levels.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.585-591
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• 2017

Turbocharging is widely used in diesel and gasoline engines as an effective way to reduce fuel consumption. But turbochargers have turbo-lag due to mechanical friction losses. Bearing friction losses are a major cause of mechanical friction losses and are particularly intensified in the lower speed range of the engine. Current turbochargers mostly use oil bearings (two journal bearings and one thrust bearing). In this study, we focus on the bearing friction in the lower speed range. Experimental equipment was made using a drive motor, load cell, magnetic coupling, and oil control system. We measured the friction losses of the turbocharger while considering the influence of the rotation speed, oil temperature, and pressure. The friction power losses increased exponentially when the turbocharger speed increased.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.9
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• pp.5415-5420
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• 2013

Background: Cell cycle deregulation is a major component of carcinogenesis. The p53 tumor suppressor gene plays an important role in regulating cell cycle arrest, and mouse double minute 2 (MDM2) is a key regulator of p53 activity and degradation. Abnormal expression of p53 and MDM2 occurs in various cancers including lung cancer. Methods: We investigated the distribution of the p53 Arg72Pro (rs1042522) and MDM2 SNP309 (rs2279744) genotypes in patients and healthy control subjects to assess whether these single nucleotide polymorphisms (SNPs) are associated with an increased risk of lung adenocarcinomas in Chinese female non-smokers. Genotypes of 764 patients and 983 healthy controls were determined using the TaqMan SNP genotyping assay. Results: The p53 Pro/Pro genotype (adjusted OR = 1.55, 95% CI = 1.17-2.06) significantly correlated with an increased risk of lung adenocarcinoma, compared with the Arg/Arg genotype. An increased risk was also noted for MDM2 GG genotype (adjusted OR = 1.68, 95% CI = 1.27-2.21) compared with the TT genotype. Combined p53 Pro/Pro and MDM2 GG genotypes (adjusted OR = 2.66, 95% CI = 1.54-4.60) had a supermultiplicative interaction with respect to lung adenocarcinoma risk. We also found that cooking oil fumes, fuel smoke, and passive smoking may increase the risk of lung adenocarcinomas in Chinese female non-smokers who carry p53 or MDM2 mutant alleles. Conclusions: P53 Arg72Pro and MDM2 SNP309 polymorphisms, either alone or in combination, are associated with an increased lung adenocarcinoma risk in Chinese female non-smokers.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.151-151
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• 2011

오늘날 에너지문제는 인류가 직면한 가장 중요한 당면과제 중 하나이다. 석유, 석탄과 같은 화석에너지는 점점 고갈되어 가고 있으며, 이산화탄소 배출로 인한 기후변화도 해결이 시급한 문제이다. 이러한 문제들을 해결하기 위한 방안으로 신재생에너지의 중요성이 부각되고 있다. 특히 신재생에너지 기술 중 태양전지는 미국, 일본, 유럽, 중국 등 많은 국가에서 기술개발 및 보급에 앞장서고 있으며, 시장선점을 위한 기술개발 경쟁이 치열하다. 또한 연료전지의 경우 전기와 열을 동시에 생산 가능하며, 다른 에너지 변환기보다 훨씬 높은 효율을 가지고 있어 신에너지원으로서 주목받고 있다. 이와 함께 기후변화에 실질적인 해결책으로 세계는 CCS에 기대하고 있으며, 기술개발 및 실증을 위한 국제공동연구도 활발하게 진행 중이다. 본 논문에서는 이러한 중요성을 인식하여 태양전지, 연료전지 그리고 CCS에 대하여 국내외 에너지기술 활용도를 분석하였다. 활용도 분석을 위하여 특허등록건수, 특허의 피인용 정보와 이를 활용한 CPP지수를 산출하였다. 오늘날 특허는 국가나 기업 등 특정 주체에 대한 기술력 또는 혁신성을 측정하거나, 기술개발 동향을 파악하기 위한 중요한 정보로 사용된다. 특히 CPP지수(특허당 피인용지수)는 분석대상(국가, 기업 등)의 특허가 이후의 기술혁신 활동에 어느 정도의 활용되어 영향을 미쳤는가를 보여주는 지표로써, 특정 국가나 기업의 기술혁신 활동의 수준 및 혁신성과의 가치를 살펴 볼 수 있다. 이를 통하여 국내의 에너지기술 경쟁력을 살펴보고 시사점을 도출하였다. 우선 특허데이터 수집을 위하여 톰슨 이노베이션을 활용하여 2001년부터 2010년까지 미국, 일본, 유럽, 한국에 등록된 특허를 검색하였으며, 특허등록번호를 중심으로 중복데이터를 제거하였다. 또한 특허명칭, 요약정보를 통하여 노이즈를 제거하였다. 노이즈가 제거된 특허를 활용하여 기술별, 국가별 기술개발 동향을 살펴보았으며, CPP지수를 통하여 기술별, 국가별 활용도를 분석하였다. 분석 결과, 태양전지의 경우 대부분의 국가에서 특허건수가 매년 증가함에 따라, 지속적으로 기술경쟁이 심화되고 있는 것으로 분석되었다. 또한 한국의 CPP지수는 미국, 일본 등 주요 경쟁국가에 비해 상당히 낮게 나타나 기술 활용 수준이 낮은 것으로 분석되었다. 따라서 핵심기술 개발과 같은 에너지기술의 질적수준을 높이기 위한 대책마련이 필요한 실정이다. 본 논문의 결과를 통하여 특허를 위한 기술개발이 아닌 보다 활용성이 높은 기술개발이 이루어지기를 바라며, 나아가 국가에너지기술 경쟁력을 높이는데 기여할 것으로 기대한다.

• Membrane Journal
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• v.24 no.4
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• pp.301-310
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• 2014

In this study, the silica nanoparticles were considerably chosen to improve a dimensional stability, proton transport and electrochemical performance of the resulting inorganic-organic nanocomposite membranes. For this purpose, hydrophobic silica (Aerosil$^{(R)}$ 812, Degussa) and hydrophilic silica (Aerosil$^{(R)}$ 380, Degussa) nanoparticles were, respectively, introduced into a Sulfonated poly(arylene ether sulfone) (SPAES) polymer matrix. The $SiO_2$ particles are evenly dispersed in a SPAES matrix by the aid of a non-ionic surfactant (Pluronics$^{(R)}$ L64). A $SiO_2$ content plays an important role in membrane microstructures and membrane properties such as proton conductivity and water uptake. Therefore, to study nanocomposite membranes with excessive amount of silica, the content of silica nanoparticles were increased up to 5 wt%. Interestingly, a hydrophobic $SiO_2$ containing nanocomposite membrane showed better electrochemical performance (29% higher than pristine SPAES) despite of low proton conductivity due to its adhesive properties with a catalyst layer in a single cell test. All the silica-SPAES membranes exhibited better performance than a pristine SPAES membrane.

• Korean Chemical Engineering Research
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• v.43 no.1
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• pp.118-124
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• 2005

In this study, a novel deposition method of Pt catalysts onto Nafion membranes modified with polypyrrole (PPy) has been proposed for PEMFC application. The PPy/Nafion composite membranes were fabricated by chemical polymerization of pyrrole using $FeCl_3$ and $Na_2S_2O_8$ as initiator. The proton conductivity and water uptake of the chemically prepared PPy/Nafion composites were investigated. The ionic conductivity and water uptake of PPy/Nafion composite membrane prepared with $Na_2S_2O_8$ were decreased with polymerization time of pyrrole. In the case of $FeCl_3$, the ionic conductivity was almost retained and the water uptake was decreased with polymerization time of pyrrole. When the Pt particle was deposited on PPy/Nafion composites membrane by chemical reduction of $H_2PtCl_6$, the Pt loading on Nafion membrane was enhanced by polypyrrole due to electronic conduction property. The performance evaluation with membrane electrode assembly composed of Pt/PPy/Nafion composite and diffusion electrode was carried out using a single cell. As a result of fuel cell test, current density of $569mA/cm^2$ at 0.3 V has been obtained for MEA contained with Pt/PPy/Nafion composite. This study shows that direct deposition of Pt catalysts on Nafion impregnated polypyrrole is a promising method to prepare thin catalyst layer for the PEMFC.

• Korean Chemical Engineering Research
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• v.50 no.1
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• pp.35-40
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• 2012

In this study, 1-(2-methoxyethyl)-3-methylimidazolium methanesulfonate ionic liquid has been synthesized, characterized and tested with respect to carbon dioxide absorption with the aim to use it as advanced absorbent materials in fossil fuel processing. The ionic liquid was synthesized by a one step method, low cost. The thermal and chemical stability of selected ionic liquid has been investigated by DSC, TGA and the structure was verified by $^1H$-NMR spectroscopy. The solubility of carbon dioxide in the methanesulfonate-based ionic liquids were measured using a high-pressure equilibrium apparatus equipped with a variable-volume view cell at 30, 50 and $70^{\circ}C$ and pressure up to 195 bar. The results show that carbon dioxide solubilities of 1-(2-methoxyethyl)-3-methylimidazolium methanesulfonate increased with pressure increasing and temperature decreasing, and the carbon dioxide absorption capacity showed 27.6 $CO_2/IL$(g/kg) at $30^{\circ}C$, 13 bar.