• Journal of Biomedical Engineering Research
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• v.44 no.3
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• pp.176-181
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• 2023

During cancer treatment, the patient's response to drugs appears differently at the cellular level. In this paper, an image-based cell phenotypic feature quantification and key feature selection method are presented to predict the response of patient-derived cancer cells to a specific drug. In order to analyze the viability characteristics of cancer cells, high-definition microscope images in which cell nuclei are fluorescently stained are used, and individual-level cell analysis is performed. To this end, first, image stitching is performed for analysis of the same environment in units of the well plates, and uneven brightness due to the effects of illumination is adjusted based on the histogram. In order to automatically segment only the cell nucleus region, which is the region of interest, from the improved image, a superpixel-based segmentation technique is applied using the fluorescence expression level and morphological information. After extracting 242 types of features from the image through the segmented cell region information, only the features related to cell viability are selected through the ReliefF algorithm. The proposed method can be applied to cell image-based phenotypic screening to determine a patient's response to a drug.

• Journal of Information Display
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• v.12 no.1
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• pp.29-35
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• 2011

In this study, plasma display panels with three different cell volumes were prepared by changing the spaces between the vertical barrier ribs into two and three times the reference structure. The discharge gap and area of the segmented ITO electrode were the same for the three cases, and Ne.20%Xe gas was used. The luminance and luminance efficiency were measured using applied voltage variations. The time evolution and intensity distribution of the infrared, which are related to the vacuum ultraviolet, were observed via intensified, charged, coupled device, and the visible-light intensity profiles were observed using PR-900 to analyze the discharge phenomena in the discharge cell.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.93.2-93.2
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• 2012

연료전지는 전기화학반응을 이용한 발전 장치로서 기존 장치에 비하여 발전 효율이 높아 화석연료를 사용하면서 현재 당면 과제인 $CO_2$ 배출량 절감이 가능하고, 환경 보전성이 우수하여 미래의 전원으로 많은 연구개발이 진행되고 있다. 특히 제3세대 연료전지라 불리는 고체산화물 연료전지(Solid Oxide Fuel Cell이하 SOFC)는 고가의 외부 개질 장치 없이도 연료가 갖는 화학에너지를 연소과정 없이, 공기와 $H_2$, CO, $CH_4$와 같은 환원성 가스를 공급받아 $600{\sim}1000^{\circ}C$에서 전기화학적 반응을 통하여 직접 전기를 얻는 방식이며, 낮은 소음과 진동으로 인하여 온 사이트(On-site) 발전이 가능한 장점이 있는 연료전지이다. Decalcomanie는 전사용지에 Screen printing하여 건조 후 coating하는 방법으로 기존의 여러 coating 방법보다 다전지셀 제작이나 Buffer layer의 적용이 용이하고, 소재의 크기나 두께조절이 간편하며, 구성층의 표면조도나 굴곡에 대응이 용이한 방법이다. 새로운 Decalcomanie를 사용하여 평관형 다전지식 SOFC Cell 제작 및 각 Buffer layer에 적용, Screen printing법과 동일한 Cell 제조 후 MPD와 Impedance 분석을 통하여 Support 위에 전사지를 이용, 적층한 Cell의 전기화학적 특성에 관하여 분석하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.273-273
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• 2009

고체산화물 연료전지 (Solid Oxide Fuel Cell, 이하 SOFC)는 제조형태에 따라 크게 평판형과 원통형으로 구분할 수 있다. 단위면적당 출력 효율이 높은 평판형의 장점과 원통형의 밀봉이 용이한 장점을 동시에 가지는 평관형 형태로 지지체를 제작하였으며, 셀의 배치를 평면상 직렬로 연결하는 다전지식으로 구성함으로 전극의 길이나, 셀 간격을 기존 평판형이나 원통형에 비해 대폭 감소시켜 단위면적당 전압 및 출력효율을 높이고자 하였다. Segmented 평관형 지지체의 소재로는 연료전지의 성능 특성에 관여하지 않으며 열사이클 저항성과 기계적 강도가 우수한 spinel구조를 가지는 $MgAl_2O_4$를 선정하였다. 연료가스의 원활한 공급이 가능하도록 carbon을 기공 전구체로 사용하여 압출성형하였으며 건조과정에서 crack이 생기지 않는 공정을 확립한 후 $1400^{\circ}C$ 에서 소결하였다. 제조된 지지체는 수은침투법과 3점 굽힘 강도법으로 기공율과 기계적 강도를 각각 측정하였다. Anode를 스크린 프린팅법으로 지지체 위에 적층한 후 미세구조를 확인하였고 이를 바탕으로 다공성이며 기계적 강도를 가지고 음극과의 반응이 없는 우수한 지지체를 제조할 수 있었다.

• Journal of the Korean Ceramic Society
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• v.51 no.4
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• pp.357-361
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• 2014

An Ni-Fe/YSZ core-shell structured anode for uniform microstructure and catalytic activity was synthesized. Flat tubular segmented-in-series solid oxide fuel cell-stacks were prepared by decalcomania method using synthesized anode powder. The Ni-Fe/YSZ core-shell anode exhibited better electrical conductivity than a commercially available Ni-YSZ cermet anode. Also power output increased by 1.3 times with a higher open circuit voltage. These results can be attributed to the uniformly distributed Ni particles in the YSZ framework. The impedance spectra of a Ni-Fe/YSZ core-shell anode showed comparable reduced ohmic resistance similar to those of the commercially available Ni-YSZ cermet anodes.

• Transactions on Electrical and Electronic Materials
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• v.6 no.2
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• pp.78-84
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• 2005

Standard crystalline solar cells are generally fabricated with the front grid pattern of silver paste contact. We have reported a detailed theoretical analysis of the proposed segmented cross grid line pattern in this paper. This work was carried out for the optimization of spacing and width of grid finger, main busbar and sub-busbar. The overall electrical and optical losses due to front contact were brought down to $10\%$ or even less as compared to the usual loss of $15\%$ or more in the conventional screen printed silver paste technology by choosing proper grid pattern and optimizing the grid parameters. The total normalized power loss for segmented mesh grid with plated metal contact was also observed and the total power loss could be brought down to $10.04\%$ unlike $11.57\%$ in the case of continuous grid and plated contact. This paper is able to outline the limitations of conventional screen printed contact.

• Transactions on Control, Automation and Systems Engineering
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• v.4 no.3
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• pp.224-230
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• 2002

In this paper, a counting algorithm hybridized with an adaptive automatic thresholding method based on Otsu's method and the algorithm that elongates markers obtained by the well-known watershed algorithm is proposed to enhance the exactness of the microcell counting in microscopic images. The proposed counting algorithm can be stated as follows. The transformed full image captured by CCD camera set up at microscope is divided into cropped images of m$\times$n blocks with an appropriate size. The thresholding value of the cropped image is obtained by Otsu's method and the image is transformed into binary image. The microbial cell images below prespecified pixels are regarded as noise and are removed in tile binary image. The smoothing procedure is done by the area opening and the morphological filter. Watershed algorithm and the elongating marker algorithm are applied. By repeating the above stated procedure for m$\times$n blocks, the m$\times$n segmented images are obtained. A superposed image with the size of 640$\times$480 pixels as same as original image is obtained from the m$\times$n segmented block images. By labeling the superposed image, the counting result on the image of microbial cells is achieved. To prove the effectiveness of the proposed mettled in counting the microbial cell on the image, we used Acinetobacter sp., a kind of ammonia-oxidizing bacteria, and compared the proposed method with the global Otsu's method the traditional watershed algorithm based on global thresholding value and human visual method. The result counted by the proposed method shows more approximated result to the human visual counting method than the result counted by any other method.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.6
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• pp.842-851
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• 2011

A multi-cell test system with 25 independent cells is used to test different electrode materials simultaneously for polymer electrolyte membrane fuel cells (PEMFCs). Twenty-five segmented membrane electrode assemblies (MEAs) having the same or different Pt-loading are prepared to analyze the performance deviation of cells in the multi-cell test system. Improvements in the multi-cell test system are made by ensuring that the system performs voltage sensing for the cells individually and inserting optimum gaskets between the MEAs and the graphite plates. The cell performances are improved and their deviations are significantly decreased by these modifications. The performance deviations changed according to various cell configurations because the operating conditions of the cells, such as the gas flow and concentration, differed. This cell system can be used to test multiple electrodes simultaneously because it shows relatively uniform performance under the same conditions as well as linear correlation with various catalyst loadings.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.29-32
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• 2007

We analyzed the effect of cell resolution on the luminous efficacy through three-dimensional numerical simulation to understand the inherent discharge mechanism change in the plasma display panel. As the resolution increases from VGA to Full HD, the luminous efficacy decreases. With higher Xe content, VUV generation efficacy of Full HD becomes much lower than those of VGA or XGA cells, due to the increased plasma loss and lower electron heating. However a long electrode gap $140{\mu}m$ in Full HD cell with Ne-Xe [20%] results in the high luminous efficacy comparable to that of the XGA cell with $60{\mu}m$ gap. When comparing the effects of Xe content variation on the luminous efficacy of two different subpixel types, i. e., SDE (Segmented electrode in Delta color arrayed, Enclosed subpixel) [1] and conventional stripe barrier type in the XGA and Full HD cells, the luminous efficacy of SDE structure shows higher improvement in Full HD resolution compared with that of conventional type XGA cell, whose cause is identified as the reduced plasma loss.

• The Journal of the Korea Contents Association
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• v.11 no.5
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• pp.84-92
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• 2011

The automated segmentation technique of cell region in Bio Images helps biologists understand complex functions of cells. It is mightly important in that it can process the analysis of cells automatically which has been done manually before. The conventional methods for segmentation of cell and nuclei from multi-channel images consist of two steps. In the first step nuclei are extracted from DNA channel, and used as initial contour for the second step. In the second step cytoplasm are segmented from Actin channel by using Active Contour model based on intensity. However, conventional studies have some limitation that they let the cell segmentation performance fall by not considering inhomogeneous intensity problem in cell images. Therefore, the paper consider correlation between DNA and Actin channel, and then proposes the preprocessing algorithm by which the brightness of cell inside in Actin channel can be compensated homogeneously by using DNA channel information. Experiment result show that the proposed preprocessing method improves the cell segmentation performance compared to the conventional method.