• 한국정밀공학회지
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• 제23권2호
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• pp.81-87
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• 2006

This study has been focused on the analysis of high speed shear forming process for lead-acid battery grids. The grid plays an important role of electrical charge. It is necessary to ensure the best battery's performance that the grid should have a best quality. The clearance between punch and die, the velocity of punch and the critical damage value are very important parameters for making a good grid form. The finite element analysis of the shear forming process is carried out by measuring and optimizing these three important parameters. The result of this study concludes that these parameters has a great influence on grid quality.

• 한국정밀공학회지
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• 제31권11호
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• pp.969-974
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• 2014

Previously fabricated electronic devices were used for vacuum manufacturing processes such as conventional semiconductor manufacturing. However, they are difficult to apply to continuous processes such as roll-to-roll printing, which results in very high device manufacturing and processing costs. Therefore, many developers have been interested in applying continuous processes to contact printing or noncontact printing technologies and they proposed various continuous printing techniques instead of conventional batch coating. In this paper, we proposed improved gravure offset printing process as one of the contact printing technique. We used etching pattern geometry with soft core blanket roll for printing of ultra fine line below the 10um.Using this technique we obtained flexible metal grid mesh film as transparent conductive film.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1997년도 추계학술대회논문집
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• pp.147-152
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• 1997

This paper presents a method for measuring and analyzing strains in sheet metal forming by stereo vision system. A better understanding and evaluation of the formability can be achieved by analyzing stain distribution in deformed sheet metals. By means of image processing technique, it is possible to get strain distribution efficiently. For measuring strain automatically and accurately, algorithms for camera calibration, grid detection, stereo matching and strain analysis has been developed and verified by experiments with GUI(Graphic User Interface).

• 한국자동차공학회논문집
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• 제6권4호
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• pp.141-150
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• 1998

The measurement of strains in stamped sheet metal is essential to the design and manufacture of sound sheet metal products. The measured strains can also be used in verifying the reliability of the computer analysis such as finite element analysis. In most engineering applications, strains are measured from the deformed square grids or deformed circular grids in comparison with the initial undeformed grids. In such a case, however, strains are averaged in each grid and the localized strain in a region smaller than a grid size can not be measured. In the present study, the B-spline surface interpolation technique is introduced in order to measure the strains more exactly and effectively. The strains calculated by using the surface interpolation technique are compared with the strains calculated from the three-noded grids as well as with the finite element analysis.

• E2M - 전기 전자와 첨단 소재
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• 제10권10호
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• pp.1034-1040
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• 1997

A solar cell conversion effiency was degraded by grain boundary effect in polycrystalline silicon. Grain boundaries acted as potential barriers as well as recombination centers for the photo-generated carriers. To reduce these effects of the grain boundaries we investigated various influencing factors such as emitter thickness thermal treatment preferential chemical etching of grain boundaries grid design contact metal and top metallization along boundaries. Pretreatment in $N_2$atmosphere and gettering by POCl$_3$and Al were performed to obtain multicrystalline silicon of the reduced defect density. Structural electrical and optical properties of slar cells were characterized before and after each fabrication process. Improved conversion efficiencies of solar cell were obtained by a combination of pretreatment above 90$0^{\circ}C$ emitter layer of 0.43${\mu}{\textrm}{m}$ Al diffusion in to grain boundaries on rear side fine grid finger top Yb metal and buried contact metallization along grain boundaries.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 추계학술대회 논문집
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• pp.483-484
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• 2007

• 한국정밀공학회지
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• 제30권6호
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• pp.578-583
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• 2013

The lighting devices using organic light emitting diodes (OLEDs) are actively researched because of the various advantages such as high power efficiency and 2-dimensitonal lighting emitting. To commercialize those OLED lighting devices, the manufacturing cost must be downed to comparable price with conventional light sources. Here, we demonstrate a reverse gravure-offset or gravure off-set printed metal electrode for the auxiliary electrode for OLED lighting devices. For the fabricated OLED's auxiliary electrode, we used Ag nano-paste and printed metal grid structure with a line width and spacing of several ten and hundred micrometer by using gravure-offset printing. In the end the printing metal grid pattern are successfully achieved by optimization of various experimental conditions such as printing pressure, printing speed and printing delay time.

• Nuclear Engineering and Technology
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• 제43권2호
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• pp.149-158
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• 2011

Metal waste generated from the pyroprocessing of 10 MtU of spent fuel was classified by comparing the specific activity of a relevant radionuclide with the limit value of the specific activity specified in the Korean acceptance criteria for a lowand intermediate-level waste repository. A Korean Optimized Fuel Assembly design with a 17${\times}$17 array, an initial enrichment of 4.5 weight-percent, discharge burn-up of 55 GWD/MtU, and a 10-year cooling time was considered. Initially, the mass and volume of each structural component of the assembly were calculated in detail, and a source term analysis was subsequently performed using ORIGEN-S for these components. An activation cross-section library generated by the KENO-VI/ORIGEN-S module was utilized for top-end and bottom-end pieces. As a result, an Inconel grid plate, a SUS plenum spring, a SUS guide tube subpart, SUS top-end and bottom-end pieces, and an Inconel top-end leaf spring were determined to be unacceptable for the Gyeongju low- and intermediate-level waste repository, as these waste products exceeded the acceptance criteria. In contrast, a Zircaloy grid plate and guide tube can be placed in the Gyeongju repository. Non-contaminated Zircaloy cladding occupying 76% of the metal waste was found to have a lower level of specific activity than the limit value. However, Zircaloy cladding contaminated by fission products and actinides during the decladding process of pyroprocessing was revealed to have 52 and 2 times higher specific activity levels than the limit values for alpha and $^{90}Sr$, respectively. Finally, it was found that 88.7% of the metal waste from the 17${\times}$17 Korean Optimized Fuel Assembly design should be disposed of in a deep geological repository. Therefore, it can be summarized that separation technology with a higher decontamination factor for transuranics and strontium should be developed for the efficient management of metal waste resulting from pyroprocessing.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2002년도 제7회 단조 심포지엄
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• pp.105-112
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• 2002

A new grid-based approach is presented for automatic generation of hexahedral meshes for simulation of plastic deformation in metal forming. In this approach, special enveloping schemes are applied, to eradicate the sources of the degenerate elements that may appear in a generated mesh. The schemes are described in detail, along with a complete procedure for mesh generation. The capability of the approach to deal with an arbitrary, 3-D process geometry is demonstrated through application to a selected forming problem.

• 한국전자파학회논문지
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• 제12권2호
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• pp.278-284
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• 2001

본 논문에서는 기울어진 금속 경계면을 삼각형 격자법으로 해석하고, 계단 근사법과 비교하였다. 특시, 삼각형 격자법에서 금속-유전체간의 경사각도에 대한 오차 범위를 밝혔다. 그결과, 삼각형 격자법에서 경사각이 30。이상 60。이하인 경우, 계단 근사법에 비하여 정확도가 향상되고, 계산속도 및 메로미를 줄일 수 있었다. 그러나 이 범위를 벗어나는 경우, 격자의 한 변의 길이가 상대적으로 늘어나 정확한 해석이 되지 않았다.