• Journal of Radiation Industry
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• v.4 no.4
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• pp.359-364
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• 2010

PVDF-HFP (binder)/silylated alumina (inorganic particle)-coated PE (polyethylene) separators were with various compositions of binder and inorganic particle were prepared by a dip-coating process with humidity control (R.H. 25% and 50%) using electron beam irradiation. The morphology of the coated PVDF-$HFP/Al_2O_3$ layer with various compositions of PVDF-HFP and $Al_2O_3$, and humidity condition was found to be an important factor in determining ionic conductivity of the prepared separators. The PVDF-$HFP/Al_2O_3$ (5/5)-coated PE separator prepared at R.H. 50% followed by electron beam irradiation at 200 kGy was applied for lithium-ion polymer battery and the cell test results showed improved high-rate discharge performance and better cyclic stability compared to the cells with the bare PE and the PVDF-HFP-coated PE separators.

• Journal of Radiation Industry
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• v.5 no.2
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• pp.151-157
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• 2011

Crosslinked SPEEK/PVDF membrane were prepared by EB radiation method with various contents of PVDF. The prepared membranes were subjected to a comparative study of proton exchange membranes for fuel cell appreciations. The crosslinked SPEEK/PVDF membranes were characterized by using DMA, DSC and SAXS. The DMA data indicate that the ionic modulus values and cluster $T_g$ decrease with increasing PVDF content. Thus, it was suggested that the number of clustering in the crosslinked membranes can be reduced with increasing PVDF content. The DSC results were shown that the degree of crystalline of the membrane increased with increasing PVDF content. The morphology of the crosslinkied membranes was shown that with increasing PVDF content, the number of crystalline domain of the SPEEK/PVDF membranes increased but ionic aggregation of the membranes decreased. The water uptake behavior, ionic exchange capacity (IEC) and proton conductivity were decreased with increasing PVDF content. The overall findings suggest that the crosslinked membranes offer the possibility for improving the performance of PEMFC, provided that the membranes have thermal and hydration stability.

• Journal of Radiation Industry
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• v.6 no.2
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• pp.171-176
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• 2012

In this study, a crosslinked poly(styrene-butadiene-styrene) [SBS] block copolymers were prepared by using gamma ray irradiation method. The effects of various radiation doses on the degree of crosslinking, thermo property, and morphology of crosslinked SBS block copolymer were investigated. The degree of crosslinking of crosslinked SBS block copolymers were measured by gel-fraction and FT-IR. It was found that the degree of crosslinking of crosslinked SBS block copolymers increases with increase of the irradiation dose while the TGA result shows that the initial degradation temperature of irradiated SBS block copolymer was shifted to lower temperature with increasing irradiation dose. These results indicate that degradation reaction also occurs when SBS block copolymer is exposed to gamma ray irradiation for crosslinking reaction. The SAXS and FE-SEM results indicate that the phase separation of the styrene block and butadiene block was reduced with increasing irradiation dose.

• Polymer(Korea)
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• v.36 no.6
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• pp.816-821
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• 2012

In this study, silane-crosslinked proton exchange membranes were prepared by step-wise radiation grafting of styrene and 3-(trimethoxysilyl)propyl methacrylate (TMSPM) onto an poly(ethylene-co-tetrafluoroethylene) (ETFE) film and followed by sol-gel processing and sulfonation. The sequentially grafted films with styrene to provide the proton conductivity and TMSPM to form the crosslinked structure were prepared by different grafting order. The structural changes and thermal properties of the prepared films were investigated by FTIR and TGA, respectively. After the introduction of sulfonic acid functional groups, the distributions of sulfonic acid group and silicon atoms at the inside of the sulfonated membranes were analyzed by SEM-EDX.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.106.1-106.1
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• 2010

석탄가스화기술은 매장량이 풍부하여 안정적인 공급이 보장되는 석탄을 이용함과 동시에 환경오염물질 감소라는 사회적 요구조건을 충족시키면서 화학제품, 석탄-가스화, 석탄-디젤화, 연료전지, 복합발전 등 다양한 분야에 응용이 가능한 장점이 있다. 특히 석탄가스화복합기술(Intergrated Coal Gasification Combined Cycle, IGCC)은 석탄을 고온, 고압하에서 가스화시켜 일산화탄소(CO), 수소($H_2$)가 주성분인 합성가스를 제조, 정제 후 가스터빈 및 증기터빈을 복합으로 구동하여 전기를 생산하는 친환경 차세대 발전기술로 주목을 받고 있다. 현재 IGCC 기술은 세계적으로 볼 때 상용화단계에 있고, 우리나라의 경우 한국형 IGCC 기술의 확보를 위한 연구사업이 진행중에 있다. 본 연구는 IGCC 발전플랜트의 발전효율을 결정하는 가장 중요한 부분이라 할 수 있는 가스화반응기의 모델링 기술을 개발하는 목적으로 진행되었다. 본 연구에서는 석탄가스화 반응기에서 발생하는 석탄의 휘발화와 Char의 표면반응 그리고 기상에서의 가스화반응등의 현상을 전산유체역학(Computational Fluid Dynamics)을 이용하여 모델링하는 방법론이 연구되었다. 해석을 위한 형상은 해석에 소요되는 시간을 줄이고, 형상이 해석결과에 미치는 영향을 줄이고자 2차원으로 구성하였다. 해석을 위한 수학적모델으로는 난류모델, 가스화반응모델, Lagrangian particle tracking, Char reaction 등을 포함하였고, 해석을 위한 Solver는 Fluent를 이용하였다. 모델링결과에 의해 예측되는 합성가스의 조성을 상용급 IGCC 가스화기의 운전결과와 비교해 본 결과 본 연구에서 설정한 모델로 예측되는 온도 및 가스농도가 실험치와 유사하게 나타남을 알 수 있었고 이를 통하여 본 연구에서 설정한 모델링방법이 적절함을 알 수 있었다.

• International Commerce and Information Review
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• v.16 no.4
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• pp.247-261
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• 2014

In this study, it investigates the highly controversial issue "low carbon car subsidy". Through the policy's intent, purpose, and necessity, it aims to present alternatives for automotive industry development. Introducing the low carbon car subsidy will bring a huge change to the vehicle purchase practices by changing vehicle purchase cost. It expects that this change will reduce greenhouse gas emission from vehicles. For successful settlement of the system, it shall set up the target sections for subsidy and levy appropriately in order to get the nation's consensus. Additionally, it has to conduct sufficient reviews the measures such as adjustment to the existing auto tax, divided payments of burden charge, etc before enforcing the system. In terms of the automobile industry, it must do their level best in technical development in order to meet the carbon dioxide emission level of imported cars until the enforcement. Also, the government has to strengthen its support to the industry.

• Korean Journal of Remote Sensing
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• v.29 no.5
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• pp.509-516
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• 2013

Since traditional linear feature extraction methods are unable to handle nonlinear characteristics often exhibited in hyperspectral imagery, nonlinear feature extraction, also known as manifold learning, is receiving increased attention in hyperspectral remote sensing society as well as other community. A most widely used manifold Isomap is generally promising good results in classification and spectral unmixing tasks, but significantly high computational overhead is problematic, especially for large scale remotely sensed data. A small subset of distinguishing points, referred to as landmarks, is proposed as a solution. This study proposes a new robust and controllable landmark selection method based on the maximum volume of the simplex spanned by landmarks. The experiments are conducted to compare classification accuracies with standard deviation according to sampling methods, the number of landmarks, and processing time. The proposed method could employ both classification accuracy and computational efficiency.

• Polymer(Korea)
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• v.38 no.4
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• pp.457-463
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• 2014

In this study, the changes in the chemical structure and the physical property of fluoropolymer films (PTFE, FEP, PFA, PVDF, and ETFE) induced by $Co^{60}$ gamma ray in air, $N_2$, and vacuum environments were investigated. FTIR spectra of the irradiated fluoropolymers indicate that the oxidation proceeded by the reaction of radicals generated by irradiation with oxygen in air. The changes in the heat of fusion and the degree of crystallinity of the irradiated fluoropolymers were investigated using DSC and the results indicate that the scission and crosslinking reactions of the irradiated fluoropolymers were largely influenced by the chemical structure. It was also found that the mechanical property of the irradiated fluoropolymer films under an air atmosphere was significantly decreased.

• Polymer(Korea)
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• v.38 no.3
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• pp.293-298
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• 2014

We prepared hydrophilic porous supporters for the reinforced composite fuel cell membrane by radiation grafting of acrylonitrile (AN) and hydrophilic sodium allylsulfonate (SAS) into a porous polytetrafluoroethylene (PTFE) supporter. The physicochemical properties of the supporters prepared under various reaction conditions such as molar ratio of SAS/AN, monomer concentration, and irradiation dose were evaluated. FTIR was utilized to confirm the successful introduction of SAS/AN copolymer chains into the porous PTFE. The pores of the porous PTFE film were found to be decreased with an increase in the degree of grafting by using FE-SEM and gurley number. Furthermore, by analyzing the degree of grafting, contact angle, and TBO (toluidine blue O) uptake, the hydrophilicity of the prepared supporters was found to increase with an increase in the degree of grafting.

• Polymer(Korea)
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• v.37 no.5
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• pp.649-655
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• 2013

In order to use as supporters for the reinforced composite fuel cell membrane, poly(acrylic acid)-grafted porous polytetrafluoroethylenes (PTFEs) were prepared via introduction of poly(acrylic acid) graft chains by a radiation grafting method. FTIR was utilized to confirm the successful introduction of poly(acrylic acid) graft polymer chains into the porous PTFEs. Contact angles were examined to observe the hydrophilicity of the surface of the prepared substrates. The result indicates that the hyrophilicity of the surface in the prepared substrates increases with an increase in the number of hydrophilic polymer chains. FE-SEM, gurley number, and tensile strength were also utilized to characterize the prepared substrates.