• Journal of the Korean Ceramic Society
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• v.53 no.2
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• pp.253-257
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• 2016

We added 0 ~ 5 wt% $YBO_3:Eu^{3+}$ nano powders in a scattering layer of a working electrode to improve the energy conversion efficiency (ECE) of a dye sensitized solar cell (DSSC). FESEM and XRD were used to characterize the microstructure and phase. PL and micro Raman were used to determine the fluorescence and the composition of $YBO_3:Eu^{3+}$ phosphor. A solar simulator and a potentiostat were used to confirm the photovoltaic properties of the DSSC with $YBO_3:Eu^{3+}$. From the results of the microstructure and phase of the fabricated $YBO_3:Eu^{3+}$ nano powders, we identified $YBO_3:Eu^{3+}$ having particle size less than 100 nm. Based on the microstructure and micro Raman results, we confirmed the existence of $YBO_3:Eu^{3+}$ in the scattering layer and found that it was dispersed uniformly. Through photovoltaic properties results, the maximum ECE was shown to be 5.20%, which can be compared to the value of 5.00% without $YBO_3:Eu^{3+}$. As these results are derived from conversion of light in the UV range into visible light by employing $YBO_3:Eu^{3+}$ in the scattering layer, these indicate that the ECE of a DSSC can be enhanced by employing an appropriate amount of $YBO_3:Eu^{3+}$.

• Journal of the Korean Ceramic Society
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• v.43 no.12 s.295
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• pp.823-828
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• 2006

One of the main issues of Solid Oxide Fuel Cells (SOFCs) is to reduce the operating temperature to $750^{\circ}C$ or less. It has advantages of improving the life of component parts and the long-term stability of a system, so the production cost could be decreased. In order to achieve that, the ohmic and polarization loss of a single cell should be minimized first. This paper presents.to fabricate anode-supported single cells with controlling microstructure as a function of particle size and volume of graphite and NiO-YSZ weight ratio. By means of optimizing the manufactural condition through microstructure analysis and performance evaluation, the single cell which had NiO-YSZ=6:4, graphite volume of 24% and graphite size of $75{\mu}m$ as the anode composition showed a distinguished power density of $510mW/cm^2$ at $650^{\circ}C$ and $810mW/cm^2$ at $700^{\circ}C$, respectively.

• Journal of the Korean Ceramic Society
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• v.36 no.9
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• pp.954-964
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• 1999

The effect of fabrication variables and microstructures on the compressive strength of open cell alumina zirconia and silicon nitride ceramics fabricated by polymeric sponge method was investigated. Bulk density and compressive strength of open cell ceramics were mainly affected by coating characteristics of ceramic slurry on polymeric sponge that controlled a shape thickness and defect of the struts. Sintering temperature was optimized for enhancement of strut strength and compressive strength of open cell ceramics. Relative density and compressive strength behaviors were relatively well matched with the predicted values. Open cell ceramics of lower relative density below 0.1 prepared by first relatively well matched with the predicted values. Open cell ceramics of lower relative density below 0.1 prepared by first coating of ceramic slurry had thin triangular prismatic struts that were often broken or longitudinally cracked. With an application of second coating of slurry shape of struts was transformed into thickner cylindrical one and defects in struts were healed but the relative density increased over 0.2 Open cell zirconia had both the highest bulk density and compressive strength and alumina had the lowest compressive strength while silicon nitrides showed relatively high compressive strength and the lowest density. Based upon the analysis open cell silicon nitride was expected to be one of potential structural ceramics with light weight.

• Journal of Welding and Joining
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• v.21 no.6
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• pp.20-25
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• 2003

Various welding methods such as Gas Tungsten Arc Welding(GTAW), magnetic force electrical resistance welding and Laser Beam Welding(LBW) are now available for end cap closure of nuclear fuel rods. Even though the resistance and GTA welding processes are widely used in manufacturing commercial fuel rods, they can not be recommended for the remote seal welding of fuel rods in the hot cell Facility due to the complexity of the electrode alignment, the difficulty in replacing parts in a remote manner and the large heat input for the thin sheath. Therefore, the Nd:YAG laser system using optical fiber transmission was selected for the end cap welding of irradiation fuel rods in the hot cell. The remote laser welding apparatus in the hot cell Facility was developed using a pulsed Nd:YAG laser of 500 watt average power with an optical fiber transmission. The weldment quality such as microstructure and mechanical strength was satisfactory. The optimum conditions of laser welding for encapsulating irradiation fuel rods in the hot cell were obtained.

• Journal of Applied Reliability
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• v.16 no.1
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• pp.41-47
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• 2016

Purpose: The purpose of this study was to evaluate electrical and structural degradation of flexible CIGS sollar cell exposed to high temperature and humid atmosphere. Method: Accelerated degradation was performed for various time under $85^{\circ}C/85%RH$ and then electrical and structural properties were analyzed by 4-point probe method, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). Results: Sheet resistance of the top ITO layer increased with exposure time to the high temperature and humid atmosphere. Blunting of the protrusion morphology of ITO layer was observed for the degraded specimen, while no phase change was detected by XRD. Oxygen was detected at the edge area after 300 hours of exposure. Conclusion: Increase in electrical resistance of the degraded CIGS solar cell under high temperature and humid environment was attribute to the oxygen or water absorption.

• Journal of the Korean Society of Industry Convergence
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• v.4 no.2
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• pp.149-155
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• 2001

The use of primitive cell volume and zero order Laue (ZOLZ) pattern is proposed to identify phase in a complex microstructure. Single convergent beam electron pattern containing higher order Laue zone ring from a nanosized region is sufficient to calculate the primitive cell volume of the phase, while ZOLZ pattern is used to determine the zone axis of the crystal. A computer program is used to screen out possible phases from the value of measured cell volume from convergent beam electron diffraction (CBED) pattern. Indexing of ZOLZ pattern follows in the program to find the zone axis of the identification from a single CBED pattern. An example of the analysis is given from the rapidly solidified $Al-Al_3Ti$ system.

• Journal of the Korean institute of surface engineering
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• v.37 no.2
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• pp.99-109
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• 2004

The effect of trace metallic additives on microstructure, glossiness and hardness of Zinc electrodeposits was investigated by using sulfate bath and flow cell system. The preferred orientation of Zn deposits with Mg-Fe additives was (10$\ell$)+(002) mixed texture, while that of Zn deposits with Mg-Fe-Cr additives was ( $10\ell$). The preferred orientation of Zn deposits with Mg-Fe-X(X:Ni,Co) additives changed from ($10\ell$)+(002) to ($10\ell$) with increasing Mg additive from 5 to 10 g/$\ell$. The surface morphology of the Zinc deposits was closely related to the preferred orientation of the deposits. The glossiness of Zn deposits with Mg-Fe additives was similar to that of pure Zn deposit. The glossiness of Zn deposits with Mg-Fe-X(X:Ni,Cr) additives was lower than that of Zn deposits with Mg-Fe additives, while that of Zn deposits with Mg-Fe-Co additives was higher than that of Zn-Mg-Fe deposits. The hardness of Zn deposits with Mg-Fe-X(Ni,Co,Cr) increased with current density and amount of Mg additive. Hardness of Zn deposits was decreased and increased in comparison with Zn-Mg-Fe deposits for Mg-Fe-Co and Mg-Fe-Cr additives, respectively.

• Journal of Fashion Business
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• v.20 no.3
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• pp.30-42
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• 2016

The objective of this study was to perform 3D solid modeling from 3D scanned surface images of cotton and silk in order to calculate the thermal heat transfer responses using numerical simulations. Continuing from the previous methodology, which provided 3D surface data for a fabric through optical measurements of the fabric microstructure, a simplified 3D solid model, containing a defined unit cell, pattern unit and fabric structure, was prepared. The loft method was used for 3D solid-model generation, and heat transfer calculations, made for the fabric, were then carried out using the 3D solid model. As a result, comprehensive protocols for 3D solid-model generation were established based on the optical measurements of real fabric samples. This method provides an effective means of using 3D information for building 3D models of actual fabrics and applying the model in numerical simulations. The developed process can be used as the basis for other analogous research areas to investigate the physical characteristics of any fabrics.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.200-202
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• 1987

Sintered CdS films on glass substrate with low electrical resistivity and high optical transmittance have been prepared by coating and sintering method. All-polycrystalline CdS/CdTe solar cells with different microstructure and properties of CdTe layer were fabricated by coating a number of CdTe slurries, which consisted of Cd and Te powders, an appropriate amount of propylene glycol and 2 or 7.5 w/o $CdC1_2$, on the sintered CdS films and by sintering the glass-CdS-(Cd+Te) composites at various temperature. To explore the dependence of the solar efficiency on the preparation conditions of the CdTe layer, Cd powder with an average particle size of $0.3{\mu}m$ or $5{\mu}m$ was prepared. The use of Cd with finer particles forms more dense or uniform microstructure of the nuclear of CdTe during the heating. Therefore the use of Cd with finer particles improves the efficiency of the sintered CdS/CdTe solar cell by improving the microstructure of sintered CdTe layer. But the difference of solar efficiency by varing a particle size of Cd is decreased with increasing amount of $CdC1_2$ in the (Cd+Te) layer. All-polycrystalline CdS/CdTe solar cells with an efficiency of 10.2% under solar irradiation have been fabricated using a Cd with finer particles.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.6
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• pp.1013-1020
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• 1997

To elicit the effect of fermentation on food quality of the watery Chinese cabbage pickles without fish sauce and red pepper paste(Baik-kimchi), changes in physicochemical properties and microstructure of fiber components were studied. Better water holding capacity(WHC) was showed in Baik-kimchi fermented at $25^{\circ}C$ than that of Baik-kimchi fermented at 5$^{\circ}C$. WHC measured at pH 2 and 6 were ranged from 10.18 to 16.79g/g dried sample for Baik-kimchi fermented at $25^{\circ}C$ and 6.51~14.58g/g dried sample for sample for samples at 5$^{\circ}C$, respectively. The higher WHC was resulted in pH controlled freeze-dried sample to pH 6 than that measured in pH 2 sample. The settling volume(SV) and oil adsorption capacity(OAC) increased with fermentation period and kept the same value for a little while, but slightly decreased in the over ripening period. Baik-kimchi fermented at $25^{\circ}C$ exhibited more shrunk microstructure of parenchyma cell and xylem than those of Baik-kimchi fermented at 5$^{\circ}C$. The appearance of SDF of the both Baik-kimchi ripened at 5$^{\circ}C$ and $25^{\circ}C$ could give granular shape, whereas the overripened Baik-kimchi had smooth surface of SDF. On the other hand, the IDF retained the original shape during fermentation.