• E2M - 전기 전자와 첨단 소재
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• 제8권6호
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• pp.768-773
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• 1995

We describe a manufacturing method and characteristics on components of molten carbonate fuel cell. Cr, Al, AI$_{2}$O$_{3}$, Co, MgO powder were mixed with Ni powder for anode components and NiO was used for cathode electrode. The electrolyte plate consisted of LiAIO$_{2}$ and carbonate (Li$_{2}$CO$_{3}$/K$_{2}$CO$_{3}$=62/38) and these three were manufactured by doctor-blade method. As a result, open circuit voltage was 1.05[VI at Ni-10Cr anode and porosity was above 60[%].

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.85-86
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• 2005

In case of attaching thermoelectric module and heat source, the polymer sheet is attached on the $Al_2O_3$ plate, which is cooling side of thermoelectric module, in order to enhance mechanical safety of the system. It is impossible to calculate the exact distribution of temperature and flow pattern of inner gap of thermoelectric module. Therefore CFD analyses was executed to determine the thermo-fluid phenomena and distribution by Fluent. As the result of these analyses, heat transfer was dominated by conduction and the difference of temperature was linear distribution according to the thickness of polymer sheet.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1675-1677
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• 2005

In case of attaching thermoelectric module and heat source, the polymer sheet is attached on the $AL_{2}O_3$ plate, which Is cold and hot side of thermoelectric module, in order to enhance mechanical safty of the system. It is impossible to calculate the exact distribution of temperature and flow pattern of inner gap of thermoelectric module. Therefore CFD(Computational Fluid Dynamics) analysis was executed to determine the thermo-fluid phenomena and distribution by Fluent. As the result of these analysis, heat transfer was dominated by conduction and the difference of temperature was linear distribution according to the thickness of polymer sheet.

• Journal of Advanced Marine Engineering and Technology
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• 제25권4호
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• pp.791-796
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• 2001

Friction stir welding is a solid phase welding process that does not melt the metal when welding. The FSW is the most remarkable and potentially useful new welding technique that is still in development. Friction stir butt welding process on 2 mm thick Al 1050 plates by utilizing a milling machine was experimentally studied. With the optimized heat generating tool welds could be achieved that are void and crack free. It was found that the friction stir welded tensile test specimens failed in the HAZ outside of the weld metal, and that the tensile strength was above 90% of that of the base metal.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.976-981
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• 2006

In case of attaching thermoelectric module and heat source, the polymer pad is attached on the $Al_2O_3$ plate, which is cooling side of thermoelectric module, in order to enhance mechanical safety of the system. It is impossible to calculate the exact distribution of temperature and flow pattern of inner gap of thermoelectric module. Therefore CFD(Computational Fluid Dynamics) analysis was executed to determine the thermo-fluid phenomena and distribution by Fluent. As the result of these analysis, heat transfer was dominated by conduction and the difference of temperature was linear distribution according to the thickness of polymer sheet.

• 한국기계가공학회지
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• 제21권8호
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• pp.87-92
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• 2022

The Al3003 aluminum plate was cut by grinding, milling, sawing, and shearing, and the hard-anodizing surface of the material was investigated. Large burrs were formed during grinding and milling. The brittle anodized film split and migrated along the deformed aluminum surface. During shearing, the hard-anodized film on the blade entry surface cracks and slides along the deforming aluminum. The cutting heat increased the ductility of the aluminum and further promoted burr formation. The oil-based coolant suppressed burrs and prevented chips from sticking to the endmill. It is better to avoid the high cutting speed and slow material feed rate conditions, which increase the cutting temperature and burr in the band saw.

• Geomechanics and Engineering
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• 제29권3호
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• pp.269-279
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• 2022

In this research, a series of dynamic numerical analysis were carried out for deep underground building structures under the various earthquake conditions. Dynamic numerical analysis model was developed based on the PLAXIS2D and calibrated with centrifuge test data from Kim et al. (2016). The hardening soil model with small strain stiffness (HSSMALL) was adopted for soil constitutive model, and interface elements was employed at the interface between plate and soil elements to simulate dynamic interaction effect. In addition, parametric study was performed for fixed condition and embedded depth. Finally, the dynamic behavior of underground building structure was thoroughly analyzed and evaluated.

• Corrosion Science and Technology
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• 제21권1호
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• pp.41-52
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• 2022

Herein, we report polyvinyl butyral composites coatings containing various loadings of 72-h bath sonicated hexagonal boron nitride particles (5 ㎛) to enhance barrier properties of coatings. Barrier properties of coatings were determined in 3.5 wt% NaCl after different time periods of immersion via electrochemical techniques such as open circuit potential, electrochemical impedance spectroscopy, and potentiodynamic polarization test. Coatings containing sonicated hexagonal boron particles exhibited improved corrosion resistance for longer periods of immersion compared to neat coating. We also discussed effects of hexagonal boron nitride on healing properties of polyvinyl butyral. Coatings containing 1.0 wt% loading of sonicated hexagonal boron nitride showed improved long-term barrier properties than coatings with other compositions. The presence of hexagonal boron nitride also affected the healing properties of polyvinyl butyral coatings besides their barrier properties. Such improved barrier properties of composites coatings were attributed to the high aspect ratio, plate-like shape, and electrically insulated nature of the filler.

• Structural Engineering and Mechanics
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• 제76권6호
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• pp.687-708
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• 2020

Openings in steel plate shear walls (SPSWs) are usually used for decorative designs, crossing locations of multiple utilities and/or structural objectives. However, earlier studies showed that generating an opening in an SPSW has a negative effect on the cyclic performance of the SPSW. Therefore, this study proposes tripling or doubling the steel-sheet-plate (SSP) layer and stiffening the opening of the SPSW to provide a solution to undesirable opening effects, improve the SPSW performance and provide the infill option of potential strengthening measures after the construction stage. The study aims to investigate the impact of SSP doubling with a stiffened opening on the cyclic behaviour, expand the essential data required by structural designers and quantify the SPSW performance factors. Validated numerical models were adopted to identify the influence of the chosen parameters on the cyclic capacity, energy dissipation, ductility, seismic performance factors (SPF) and stiffness of the suggested method. A finite Element (FE) analysis was performed via Abaqus/CAE software on half-scale single-story models of SPSWs exposed to cyclic loading. The key parameters included the number of SSP layers, the opening size ratios corresponding to the net width of the SSP, and the opening shape. The findings showed that the proposed assembly method found a negligible influence in the shear capacity with opening sizes of 10, 15, 20%. However, a deterioration in the wall strength was observed for openings with sizes of 25% and 30%. The circular opening is preferable compared with the square opening. Moreover, for all the models, the average value of the obtained ductility did not show substantial changes and the ultimate shear resistance was achieved after reaching a drift ratio of 4.36%. Additionally, the equivalent sectional area of the SSP in the twin and triple configuration of the SPSWs demonstrated approximately similar results. Compared with the single SSP layer, the proposed configuration of the twin SSP layer with a stiffened opening suggest to more sufficiency create SSP openings in the SPSW compared to that of other configurations. Finally, a tabular SPF quantification is exhibited for SPSWs with openings.

• 암석학회지
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• 제11권1호
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• pp.17-28
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• 2002

제주도 남동부 태흥리 용암류에 대한 암석학적, 지구화학적 특징에 대해 고찰하였다. 본 역의 용암류는 알칼리 현무암과 쏠리아이트 현무암으로 구분된다. 하층부에는 4매 이상의 쏠리아이트 현무암이 나타나고, 그 위를 2매의 알칼리 현무암이 덮고 있다. 쏠리아이트 현무암은 알칼리 현무암에 비해, 동일한 MgO 조성에서 $K_2O$, $P_2O_{5}$, Ba과 Ta은 낮은 값을 가지고, $SiO_2$와 CaO는 높은 값을 가진다. 미량원소의 조성 특징을 원시맨틀 값으로 규정화한 거미 성분도에서 모든 현무암질 마그마의 Ba과 Rb은 원시맨틀에 비하여 부화되어 있고, Ni 과 Cr은 결핍되어 있다. 희토류 원소를 콘드라이트 값으로 표준화했을 때 LREE가 HREE에 비해 더 부화된 패턴을 가진다. 변화 패턴은 나란한 변화를 보이며, 알칼리 현무암이 쏠리아이트 현무암보다 더 부화된 경향을 보인다. 조구적 위치 판별도에서 본 역의 용암류는 지판 내부 현무암 영역에 도시된다. 쏠리아이트 현무암의 Zr/Nb, Y/Nb, $Al_2O_3$/$P_2O_{5}$ 비는 알칼리 현무암에 비해 크며, K/Ba비는 알칼리 현무암과 쏠리아이트 현무암간에 거의 차이가 없이 일정한 값을 나타낸다. 본 연구지역의 화산암류에 대한 일련의 지화학적 특징은 알칼리 현무암과 쏠리아이트 현무암의 모마그마가 동질의 맨틀 근원암으로부터 부분용융 정도의 차이에 의해 생성되었음을 지시하며, 쏠리아이트 현무암이 알칼리 현무암보다 더 큰 정도의 부분용융으로 형성되었음을 의미한다.