• 방사선산업학회지
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• 제7권1호
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• pp.61-67
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• 2013

In this study, we developed ionic permselective membrane as a core material of redox flow battery using radiation grafting method. Two ionic permselective membranes, ETFE-g-PSSA and ETFE-g-PVBSA were prepared by radiation grafting with styrene and VBC followed by sulfonation, respectively. We confirmed that the prepared membranes were successfully prepared via FT-IR. The prepared ionic permselcetive membranes were characterized and the performance of the membranes were evaluated as ionic permselective membranes for vanadium redox flow battery.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.105.1-105.1
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• 2010

Korea Electric Power Research Institute (KEPRI) has developed a compact coal-gasification system to accumulate our experiment skills. The combustion furnace for residual oil was modified as a small size coal gasifier. Recently, coal feeding system was also upgraded to control coal feed rate more accurately. Our research group has conducted several experiments to find out the effect of $O_2$/coal ratio on the cold gas efficiency. Furthermore, the effect of $N_2$/coal ratio on the transport characteristics was also studied. According to the calculation of heat and mass balance, the cold gas efficiency was estimated to the maximum at $O_2$/coal ratio of around 0.73. But small size gasifier such as ours required higher value of $O_2$/coal ratio than that of the theoretical estimation. On the optimal $N_2$/coal ratio, we noticed that the coal feed rate was intimately related with the transporting gas pressure and the pipe diameter.

• 대한원격탐사학회지
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• 제29권4호
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• pp.399-406
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• 2013

위성 영상 자료에 대한 품질의 향상과 안정화는 다양한 목적을 가진 사용자들을 만족시킬 수 있다. 특히 절대 방사 검/보정은 영상의 광항적 품질을 유지하기 위한 척도가 된다. 본 연구에서는 초분광 영상 밴드 접합 기법과 분광 반응도를 이용하여 다중 분광 센서의 가상화를 통해 절대 방사 보정 계수의 적합성을 판단하였다. 적합성 분석을 위해 약 30분 차이로 촬영된 EO-1 Hyperion과 Landsat-8 OLI 센서의 영상을 이용하였고, 서로 다른 특성을 지닌 토지 피복으로 구성된 3개 지역을 선정하여 복사 에너지 값을 비교 하였다. 그 결과, 시공간에 따른 차이, 센서 수준의 차이를 제외하고 모든 밴드에서 0.99 이상의 적합성을 보여 주었다.

• Smart Structures and Systems
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• 제14권4호
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• pp.699-718
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• 2014

The indirect displacement estimation using acceleration and strain (IDEAS) method is extended to various types of beam structures beyond the previous validation on the prismatic or near-prismatic beams. By fusing different types of responses, the IDEAS method is able to estimate displacements containing pseudo-static components with high frequency noise to be significantly reduced. However, the concerns to the IDEAS method come from possible disagreement of the assumed sinusoidal mode shapes to the actual mode shapes, which allows the IDEAS method to be valid only for simply-supported prismatic beams and limits its applicability to real world problems. In this paper, the extension of the IDEAS method to the general types of beams is investigated by the mathematical formulation of the modal mapping matrix only for the monitored substructure, so-called monitoring span. The formulation particularly considers continuous and wide beams to extend the IDEAS method to general beam structures that reflect many real bridges. Numerical simulations using four types of beams with various irregularities are presented to show the effectiveness and accuracy of the IDEAS method in estimating displacements.

• 한국수소및신에너지학회논문집
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• 제28권6호
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• pp.721-728
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• 2017

In this work, an one-dimensional analysis on spontaneous combustion in a coal stockpile was conducted using a commercial software $gPROMS^{(R)}$ based on assumption suggested by Arioy and Akgun. According to them, it is assumed that there is temperature difference between the surface of coal particle and the gas surrounded around the particle, and it is also assumed that the velocity of the gas is constant and thus oxygen is fed to the stockpile with same velocity. The higher temperature zone is formed to the surface of the coal stockpile at the initial phase and it became deepen as time is taken. Finally it was found that the temperature difference between coal particle and the gas was calculated as $57^{\circ}C$ and spontaneous combustion have not been occurred during 6 months since coal was piled in the stock.

• 대한원격탐사학회지
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• 제34권4호
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• pp.649-659
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• 2018

The aim of this study is to develop a protocol for obtaining spectral signals that are robust to varying lighting conditions, which are often found in the Polar regions, for creating a spectral library specific to those regions. Because hyperspectral image (HSI)-derived spectra are collected on the same scale as images, they can be directly associated with image data. However, it is challenging to find precise and robust spectra that can be used for a spectral library from images taken under different lighting conditions. Hence, this study proposes a new radiometric calibration protocol that incorporates radiometric targets with a traditional vicarious calibration approach to solve issues in image-based spectrum measurements. HSIs obtained by the proposed method under different illumination levels are visually uniform and do not include any artifacts such as stripes or random noise. The extracted spectra capture spectral characteristics such as reflectance curve shapes and absorption features better than those that have not been calibrated. The results are also validated quantitatively. The calibrated spectra are shown to be very robust to varying lighting conditions and hence are suitable for a spectral library specific to the Polar regions.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 추계학술대회 초록집
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• pp.75.2-75.2
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• 2011

고온고압에서 운전되는 IGCC용 분류층 석탄가스화기는 석탄에 포함된 회 성분을 대부분 용융 슬래그 형태로 가스화기 벽을 타고 흘러내리게 하여 가스화기 하부로 배출시킨다. 이러한 용융 슬래그를 원활하게 배출시키는 것은 가스화기의 안정적인 운전에 있어서 매우 중요하다. 본 연구에서는 슬래그 층 내의 물질수지, 운동량 및 에너지 보존을 고려하여 석탄가스화기내의 슬래그 거동을 해석할 수 있는 모델 식을 유도하였다. 유도된 슬래그 거동 모델 식들을 적용하고 가스화기의 형상을 고려하여 가스화기 내부에서의 슬래그 거동을 해석하였다. 또한 슬래그 물성치들인 슬래그 점도, 슬래그 비열, 슬래그 밀도, 슬래그 열전달 계수 등을 슬래그의 조성 변화에 따라 별도로 산정하여 슬래그 해석의 입력 데이터로 사용하였다. 슬래그에 첨가되는 석회석의 비율을 해석의 주요 변수로 사용하여 가스화기 하부에서 용융 슬래그 및 고체 슬래그 두께, 용융 슬래그 층 내부에서의 슬래그 점도분포 및 슬래그 속도분포 등 슬래그 거동의 주요 특성들을 예측하였다. 해석결과로 석탄에 석회석의 첨가량을 증가시키면 슬래그의 임계점도온도(temperature of critical viscosity)와 점도가 낮아지므로 가스화기 벽면에서의 용융 슬래그의 유동속도는 빨라지며, 고체 슬래그와 용융 슬래그의 두께가 감소하는 것을 정량적으로 확인할 수 있었다.

• 한국수소및신에너지학회논문집
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• 제25권4호
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• pp.425-435
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• 2014

Simulation studies on catalytic methanation reaction in externally cooled tubular reactor filled with monolithic catalysts were carried out using a general purpose modelling tool $gPROMS^{(R)}$. We investigated the effects of operating parameters such as gas space velocity, temperature and pressure of feeding gas on temperature distribution inside the reactor, overall CO conversion, and chemical composition of product gas. In general, performance of methanation reaction is favored under low temperature and high pressure for a wide range of their values. However, methane production becomes negligible at temperatures below 573K when the reactor temperature is not high enough to ignite methanation reaction. Capacity enhancement of the reactor by increasing gas space velocity and/or gas inlet pressure resulted no significant reduction in reactor performance and heat transfer property of catalyst.

• 방사선산업학회지
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• 제6권4호
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• pp.289-297
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• 2012

Since Nafion is very expensive and shows the decreased fuel cell performance over $80^{\circ}C$ operating temperature, much work has been carried out in the search for cheaper membrane with high fuel cell performance. Radiation is known to be very useful for the preparation of the polymer electrolyte membranes since it can be effectively used for the introduction of ion conducting functional groups into the commercial film with high mechanical and chemical properties. Here, we summarize the our recent progress in the development of fuel cell membranes by utilizing radiation.

• 방사선산업학회지
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• 제5권2호
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• pp.179-184
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• 2011

In this study, several anion exchange membranes were successfully prepared by radiation grafting of vinylbenzyl chloride (VBC) monomer onto a polyethylene-co-tetrafluoroethylene (ETFE) film and subsequent quaternarization with diamins such as 1,4-diazbicyclo[2,2,2]octane, N,N,N',N'-tetramethyl-1,3-diaminopropane, N,N,N',N'-tetramethyl-1,6-diaminohexane, and trimethylamine. The anion exchange capacities of the prepared membranes were determined by using acid-base titration method. The cross-sectional morphology of the membranes was studied by using SEM instrument. The cross-sectional distribution patterns of the grafted polymers with anion exchange functional groups were also studied by EDX analysis.