• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.350-355
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• 2009

The crysralline silicon solar cell where the solar cell market grows rapidly is occupying of about 85% or more high efficiency and low cost endeavors many crystalline solar cells. The fabricaion process of high efficiency crystalline silicon solar cells necessitate complicated fabrication processes and Ti/Pd/AG contact, This metal contacts have only been used in limited areas in spite of their good srability and low contact resistance because of expensive materials and process. Commercial solar cells with screen-printed solar cells formed by using Ag paste suffer from loe fill factor and high contact resistance and low aspect ratio. Ni and Cu metal contacts have been formed by using electroless plating and light-induced electro plating techniques to replace the Ti/Pd/Ag and screen-printed Ag contacts. Copper and Silver can be plated by electro & light-induced plating method. Light-induced plating makes use the photovoltaic effect of solar cell to deposit the metal on the front contact. The cell is immersed into the electrolytic plating bath and irradiated at the front side by light source, which leads to a current density in the front side grid. Electroless plated Ni/ Electro&light-induced plated Cu/ Light-induced plated Ag contact solar cells result in an energy conversion efficiency of 16.446 % on 0.2~0.6${\Omega}$ cm, $20{\times}20mm^2$, CZ(Czochralski) wafer.

• Journal of Information Display
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• v.13 no.1
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• pp.1-6
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• 2012

Decreasing the thermal resistance is the critical issue for high-brightness light-emitting diodes. In this paper, the effects of some design factors, such as chip size (24 and 35 mil), substrate material (AlN and high-temperature co-fired ceramic), and die-attach material (Ag epoxy and PbSn solder), on the thermal-dissipation characteristics were investigated. Using the thermal transient method, the temperature sensitivity parameter, $R_{th}$ (thermal resistance), and junction temperature were estimated. The 35-mil chip showed better thermal dissipation, leading to lower thermal resistance and lower junction temperature, owing to its smaller heat source density compared with that of the 24-mil chip. By adopting an AlN substrate and a PbSn solder, which have higher thermal conductivity, the thermal resistance of the 24-mil chip can be decreased and can be made the same as that of the 35-mil chip.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.04a
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• pp.155-161
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• 1997

This Expriment is performed to describe the properties of the freezing-thawing and to find the method to enhance the freezing-thawing resistance of the high strength light weight aggregates concrete. For this purpose, we made 8 kinds of specimen of concrete mold. The light weight coarse aggregate concrete which contained AE was appeared in good condition and its durability index was more than 90% by the buffer action which owing to entained air. The light weight aggregates concrete which admixture of silca fume, was appeared that the durability index was 46.74% in spite of its high strength. I might conclude that the most important factor for freezing-thawing resistance of high strength light weight aggregate concrete is the entrained air.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.11a
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• pp.211-212
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• 2012

To prevent energy waste in buildings used heat insulator. Heat insulator materials can be classified inorganic and organic. The organic material is due to toxic gas emission, when a fire occurs. And it has lower water resistance. The inorganic material is heavy and worse thermal performance than organic materials. Technologies on energy saving and materials used in curtain walls have progressed with increase of high-rise and large buildings. However, there is little study to explain fire resistance performance of the curtain walls. This study focused on evaluation of the physical properties of light-weight inorganic foam panel for using industrial by-products materials and performance evaluation by mock up test.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.749-752
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• 2005

Normally, the degradation of concrete member exposed to fire is largely dependent on the fire scale and fire condition. With all ensuring the fire resistance structure as a method of setting the required cover thickness to fire, the RC is significantly affected from the standpoint of its structural stability that the compressive strength and elastic modulus is reduced by fire. Thus, this study is concerned with experimentally investigating fire resistance of high strength-light weight concrete. From the test result, high strength-light weight concrete is happened explosive spalling. The decrease of cross section caused by explosive spalling made sharp increasing gradient of inner temperature.

• Transactions on Electrical and Electronic Materials
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• v.8 no.3
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• pp.131-134
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• 2007

An $ITO/Alq_3/Al$ structure was used to study complex impedance of $Alq_3$ based organic light-emitting diodes. Equivalent circuit was analyzed in a device structure of $ITO/Alq_3/Al$ with a thickness layer of $Alq_3$ of 100 nm. The obtained impedance was able to be fitted using equivalent circuit model of parallel combination of resistance $R_p$ and capacitance $C_p$ with a small series resistance of $R_s$.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.7
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• pp.791-798
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• 1988

Films of Cr, Cu, and Al were deposited by the evaporation technique at the high vacuum level-high evaporation rate and the low vacuum level-low evaporation rate. We measured sheet resistance and light transmittance, and observed microstructure and diffraction pattern by TEM, and investigated oxygen content in thin film by AES. We discussed the relations among microstructure, sheet resistance, and light transmittance with AES data. We found that the films deposited at the high vacuum level-high evaporation rate have small oxygen content in thin film comparing to the films deposited at the low vacuum level-low vacuum level-low evaporation rate, and that the films having crystalline structure and larger grain size were formed in the case of the high vacuum level-high evaporation rate and they showed lower sheet resistance and lower light transmittance.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.20
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• pp.8883-8886
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• 2014

Background: Tetracycline is an antibiotic widely used for the treatment of Helicobacter pylori infection, but its effectiveness is decreasing due to increasing bacterial resistance. The aim of this study was to investigate the occurrence of 16S rRNA mutations associated with resistance or reduced susceptibility to tetracycline ofHelicobacter pylori by real-time PCR (RT-PCR) assays from culture. Materials and Methods: Tetracycline susceptibility and minimal inhibition concentration (MIC) was determined by the Epsilometer test (Etest) method. A LightCycler assay developed to detect these mutations was applied to DNA extracted from culture. The 16S rRNA of these isolates was sequenced and resistance-associated mutations were identified. From 104 isolates of H. pylori examined, 11 showed resistance to tetracycline. Results: LightCycler assay was applied to DNA extracted from 11 tetracycline-susceptible and 11 tetracycline resistance H. pylori isolates. In our study the sequencing of the H. pylori wild types in 16 s rRNA gene were AGA 926-928 with MIC (0.016 to $0.5{\mu}g/ml$), while the sequencing and MIC for resistant were GGA and AGC, (0.75 to $1.5{\mu}g/ml$), respectively. Also we found a novel mutation in 2 strains with $84^{\circ}C$ as their melting temperatures and exhibition of an A939C mutation. Conclusions: We conclude that real-time PCR is an excellent method for determination of H. pylori tetracycline resistance related mutations that could be used directly on biopsy specimens.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.200-203
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• 2003

A study on the arc resistance and light reflectance of PTFE (polytetrafluoroethylene) nozzle for circuit breaker is presented. PTFE has been used widely as a material for circuit breaker nozzle. PTFE has excellent electrical resistivity, high melt viscosity, chemical inertness, heat resistance and low loss factor. PTFE melts at $327\;^{\circ}C$ but the viscosity is very high above the melting point. In the arcing environment in a circuit breaker, the fraction of the power is emitted out of the arc and reaches the nozzle wall by radiation, causing ablation at the surface and in the depth of the wall. Some fraction of the radiation power emitted out of the arc directly break up the chemical bonds at the surface while some fraction of the radiation power penetrates into the wall, heats up the material to evaporation temperature and causes damages deeper inside the volume of the nozzle. In this paper, some fillers that have endurance in the high temperature arc environment were added into PTFE. Adding some fillers into PTFE was expected to be efficient in improving the endurability against radiation. The light reflectance and arc resistance of PTFE composites were investigated.

• Journal of Forest and Environmental Science
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• v.16 no.1
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• pp.34-41
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• 2000

This study investigated tree vigor of damaged forest by Thecodiplosis japonensis Uchida et Inouye. In damaged forest by pine gall midge, the investigation result of damaged rate section (severe, moderate, light) indicated that severe stand showed higher value of electric resistance ($k{\Omega}$) than that of light stand, the investigation result of tree density section(crowed, middle, little) indicated that crowed stand showed higher value of electric resistance than that of little stand (the value of electric resistance at which low reading show high vigor tree and high reading low vigor tree). The crown width and DBH (diameter of breast height) of external factors showed lower value of electric resistance than that of small size. The results of comparative between Crown area and value of electric resistance in each stand were $13.4m^2$ in severe stand, $10.9m^2$ in moderate stand and $7.9m^2$ in light stand. Therefore, the tree which have big crown showed low value of electric resistance (below $15k{\Omega}$)that has high possible of survial.