• Journal of the Korean Society for Precision Engineering
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• v.18 no.5
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• pp.171-176
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• 2001

Plasma Display Panel(PDP) is a type of flat panel display utilizing the light emission produced by gas discharge. Barrier Ribs of PDP separating each sub-pixel prevents optical and electrical crosstalks from adjacent sub-pixels. Mold for forming barrier ribs has been newly researched to overcome the disadvantages of conventional manufacturing process such as screen printing, sand-blasting and photosensitive glass methods. Mold for PDP barrier ribs have stripes of micro grooves transferring glass-material wall. In this paper, Stripes of grooves of which width 48${\mu}{\textrm}{m}$ and 270${\mu}{\textrm}{m}$, depth 124${\mu}{\textrm}{m}$, pitch 274${\mu}{\textrm}{m}$ was acquired by machining hard and brittle materials of WC, Silicon, Alumina with dicing saw blade. Maximum roughness of the bottom and sidewall of the grooves was respectively 120nm, 287nm in grooving WC. Maximum tilt angle caused by difference between upper-most width and lower-most width was 2$^{\circ}$. Maximum Radius of bottom curvatures was 7.75${\mu}{\textrm}{m}$. This results satisfies the specification for barrier ribs of 50 inch XGA PDP if the groove form of mold was fully transferred to the barrier ribs. Barrier ribs were formed with Silicone rubber mold, which is transferred from grooved hard materials. Silicone rubber mold has elasticity accommodating the waveness of lower glass plate of PDP.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.57.2-57.2
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• 2011

Dye-sensitized solar cells (DSSC) have recently been developed as a cost-effective photovoltaic system due to their low-cost materials and facile processing. The production of DSSC involves chemical and thermal processes but no vacuum is involved. Therefore, DSSC can be fabricated without using expensive equipment. The use of dyes and nanocrystalline $TiO_2$ is one of the most promising approaches to realize both high performance and low cost. The efficiency of the DSSC changes consequently in the particle size, morphology, crystallization and surface state of the $TiO_2$. Nanocrystalline $TiO_2$ materials have been widely used as a photo catalyst and an electron collector in DSSC. Front electrode in DSSC are required to have an extremely high porosity and surface area such that the dyes can be sufficiently adsorbed and be electronically interconnected, resulting in the efficient generation of photocurrent within cells. In this study, DSSC were fabricated by an screen printing for the $TiO_2$ thin film. $TiO_2$ nanoparticles characterized by X-ray diffractometer (XRD) and scanning electron microscope (SEM) and scanning auger microscopy (SAM) and zeta potential and electrochemical impedance spectroscopy(EIS).In addition, DSSC module was modeled and simulated using the SILVACO TCAD software program. Improve the efficiency of DSSC, the effect of $TiO_2$ thin film thickness and $TiO_2$ nanoparticle size was investigated by SILVACO TCAD software program.

• Journal of the Korean Society of Clothing and Textiles
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• v.35 no.3
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• pp.359-370
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• 2011

This study analyzes the textiles design of natural indigo dyed products in Korea and Japan. In this study, a total of 556 Korean natural indigo dyed products, and 2,730 Japanese natural indigo dyed products were used for analysis. The subjects of this study were 556 natural indigo dyed products and 2,730 Japanese natural indigo dyed products selling natural indigo dyed products which were found using search engine keywords of natural indigo dyeing and natural dyeing. Research and analysis was treated regarding the products, items, patterns, and the representation techniques of the patterns. The results of this study are as follows. In the pattern used for natural indigo dyed products, 71.4% of Korean products have no pattern, but 77.1% of Japanese products have patterns. On the representation techniques of the patterns, Korean products used tie-dyeing and a dip patterned fabric. While in the Japanese products, the most frequent patterning techniques were paraffin dye, followed by tie-dyeing, yarn-dyed and weaving, screen printing, and yarn-dyed and knitting. Regarding the kinds of patterns for natural indigo dyed products, only 8 kinds of patterns were used in Korean products; however, over 50 kinds of various patterns were used in Japanese products. Most patterns in the Korean products were ion patterns made by tie-dyeing. While in the Japanese products, the most frequent patterns were stripe patterns, followed by flower, dot, and ion patterns. Based on these research results, the problems of the textile design of Korean natural indigo dyed products were that most of the products have no pattern, and even though there were patterns, they lacked variations between the products. While in the case of Japan, they used the traditional and modem patterns of various textile representation techniques.

• Journal of Sensor Science and Technology
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• v.8 no.6
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• pp.454-460
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• 1999

$LaCoO_3$ thick-films for gas sensing layers were prepared on alumina substrate by screen printing method. The sensitivities to $C_4H_{10}$, $NH_3$, NO and CO gases were investigated for different heat treatment temperatures of the films. Their structural properties were examined by X-Ray Diffraction measurements and SEM photographs. The sensitivity of $LaCoO_3$ thick-film to CO gas was much higher than those of $C_4H_{10}$, $NH_3$, and NO gases. The optimal heat treatment and operating temperatures were $800^{\circ}C$ and $150^{\circ}C$, respectively. The sensitivities of $LaCoO_3$ thick-films to 500ppm and 1250ppm CO gas were 72% and 95%, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.12S
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• pp.1217-1223
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• 2003

Nerve gas sensor based on tin oxide was fabricated and its characteristics were examined. Target gas is dimethyl methyl phosphonate(C$_3$ $H_{9}$ $O_3$P, DMMP) that is simulant gas of nerve gas. Sensing materials were Sn $O_2$ added a-Al$_2$ $O_3$ with 0∼20wt.% and were physically mixed each material. They were deposited by screen printing method on alumina substrate. The sensor device was consisted of sensing electrode with interdigit(IDT) type in front and a heater in back side. Total size of device was 7${\times}$10${\times}$0.6㎣. Crystallite size & phase identification and morphology of fabricated Sn $O_2$ powders were analyzed by X-ray diffraction and by a scanning electron microscope, respectively. Fabricated sensor was measured as flow type and resistance change of sensing material was monitored as real time using LabVIEW program. The best sensitivity was 75% at adding 4wt.% $\alpha$-Al$_2$ $O_3$, operating temperature 30$0^{\circ}C$ to DMMP 0.5ppm. Response and recovery time were about 1 and 3min., respectively. Repetition measurement was very good with $\pm$3％ in full scale.TEX>$\pm$3％ in full scale.

• Journal of the Korean Ceramic Society
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• v.43 no.5 s.288
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• pp.299-303
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• 2006

In this paper, anode supported SOFC with columnar structured YSZ electrolyte was fabricated via Electron Beam Physical Vapor Deposition (EBPVD) method. Liquid condensation process was employed for the preparation of NiO-YSZ substrate and the high power electron beam deposition method was used for the deposition of YSZ electrolyte film. Double layered cathode with LSM-YSZ and LSM was printed on electrolyte via screen-printing method and fired at $1150^{\circ}C$ in air atmosphere for 3 h. The electrochemical performance and the long-term stability of $5{\times}5cm^2$ single cell were investigated with DC current-voltage characteristics and AC-impedance spectroscopy. According to the investigation, $5{\times}5cm^2$ sized unit cell showed the maximum power density of around $0.76W/cm^2$ at $800^{\circ}C$ and maintained the stable performance over 400 h.

• 한국태양에너지학회:학술대회논문집
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• 2011.04a
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• pp.105-110
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• 2011

The doping procedure in crystalline silicon solar cell fabrication usually contains oxygen injection during drive-in process and removal of phosphorous silicate glass(PSG). In this paper, we studied the effect of oxygen injection and PSG on conversion efficiency of solar cell. The mono crystalline silicon wafers with $156{\times}156mm^2$, $200{\mu}m$, $0.5-3.0{\Omega}{\cdot}cm$ and p-type were used. After etching $7{\mu}m$ of the surface to form the pyramidal structure, the P(phosphorous) was injected into silicon wafer using diffusion furnace to make the emitter layer. After then, the silicon nitride was deposited by the PECVD with 80 nm thickness and 2.1 refractive index. The silver and aluminium electrodes for front and back sheet, respectively, were formed by screen-printing method, followed by firing in 400-425-450-550-$880^{\circ}C$ five-zone temperature conditions to make the ohmic contact. Solar cells with four different types were fabricated with/without oxygen injection and PSG removal. Solar cell that injected oxygen during the drive-in process and removed PSG after doping process showed the 17.9 % conversion efficiency which is best in this study. This solar cells showed $35.5mA/cm^2$ of the current density, 632 mV of the open circuit voltage and 79.5 % of the fill factor.

• Korean Journal of Materials Research
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• v.21 no.10
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• pp.546-549
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• 2011

Nano-sized $SnO_2$ thick films were prepared by a screen-printing method onto $Al_2O_3$ substrates. The sensing characteristics were investigated by measuring the electrical resistance of each sensor in a test box as a function of the detection gas. The nano-sized $SnO_2$ thick film sensors were treated in a $N_2$ atmosphere. The structural properties of the nano $SnO_2$with a rutile structure according to XRD showed a (110) dominant $SnO_2$ peak. The particle size of $SnO_2$:Ni nano powders at Ni 8 wt% was about 45 nm, and the $SnO_2$ particles were found to contain many pores according to the SEM analysis. The sensitivity of the nano $SnO_2$-based sensors was measured for 5 ppm $CH_4$ gas and $CH_3CH_2CH_3$ gas at room temperature by comparing the resistance in air with that in the target gases. The results showed that the best sensitivity of $SnO_2$:Ni and $SnO_2$:Co sensors for $CH_4$ gas and $CH_3CH_2CH_3$ gas at room temperature was observed in $SnO_2$:Ni sensors doped with 8 wt% Ni. The response time of the $SnO_2$:Ni gas sensors was 10 seconds and recovery time was 15 seconds for the $CH_4$ and $CH_3CH_2CH_3$ gases.

• The Research Journal of the Costume Culture
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• v.25 no.6
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• pp.741-756
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• 2017

The natural resources of Jeju are recognized as the new regional image of that clean island. Reflecting these trends, this study is initiated to develop a textile design with the motive of persimmon, a natural resource of Jeju, and to apply it to infant's and children's clothes. Its purpose is to highlight the image of persimmon, a traditional dye, as a regional signature for Jeju. Product development procedure included, understanding the use of persimmon for fashion products, analyzing Infants' and Children's designer collections over the last three seasons (focused on 2014S/S, 2015S/S, and 2016S/S), and surveying the Children's Clothes market for persimmon dyeing in Jeju. The conclusion was that, the natural resources of Jeju are highly valuable, and should be applied to textile design and apparel products for children. Utilizing Jeju persimmon was actively studied, but, the market for the Jeju persimmon natural - dyeing products is extremely limited. Moreover, the apparel products for infants and children represent old-fashioned styles, despite their higher prices. Therefore, using the formative characteristics of persimmon for each theme was suggested for development of patterns for textile design. Pattern designs were expressed using textured textile screen-printing, embroidery and $appliqu{\acute{e}}$ for infants' and children's clothes. In this study, a total of 10 items were prepared as apparel products for infants and children. All items were designed considering mix-and-match, potential, with each other or with regular mass-market products. These results are expected to contribute to highlighting the unique image of Jeju and to help promote fashion culture products.

• Korean Journal of Materials Research
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• v.20 no.8
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• pp.408-411
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• 2010

Indium doped $SnO_2$ thick films for gas sensors were fabricated by a screen printing method on alumina substrates. The effects of indium concentration on the structural and morphological properties of the $SnO_2$ were investigated by X-ray diffraction and Scanning Electron Microscope. The structural properties of the $SnO_2$:In by X-ray diffraction showed a (110) dominant $SnO_2$ peak. The size of $SnO_2$ particles ranged from 0.05 to $0.1\;{\mu}m$, and $SnO_2$ particles were found to contain many pores, according to the SEM analysis. The thickness of the indium-doped $SnO_2$ thick films for gas sensors was about $20\;{\mu}m$, as confirmed by cross sectional SEM image. Sensitivity of the $SnO_2$:In gas sensor to 2000 ppm of $CO_2$ gas and 50 ppm of H2S gas was investigated for various indium concentrations. The highest sensitivity to $CO_2$ gas and H2S gas of the indium-doped $SnO_2$ thick films was observed at the 8 wt% and 4 wt% indium concentration, respectively. The good sensing performances of indium-doped $SnO_2$ gas sensors to $CO_2$ gas were attributed to the increase of oxygen vacancies and surface area in the $SnO_2$:In. The $SnO_2$:In gas sensors showed good selectivity to $CO_2$ gas.