• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
• /
• pp.495-500
• /
• 2001

In this study, it was analized and examined fundamental properties of Electric Pole Recycled Aggregate(EPRA) and hardened properties & chemical resistance with H$_2$SO$_4$by replacement ratios of EPRA, and the results are as follows 1) In the case of electric pole recycled coarse aggregate, All fundamental properties are better than that of normal recycled aggregate and both water absorption and amount of crushed loss are with level of natural aggregate 2) As the replacement ratio of electric pole recycled fine aggregate is increased strength development is decreased. but in the case of coarse aggregate, that of it is with level of natural aggregate 3) As the replacement ratio of electric pole recycled fine aggregate is increased chemical resistance is decreased. but in the case of coarse aggregate, that of it is with level of natural aggregate

• 한국원자력학회:학술대회논문집
• /
• 한국원자력학회 1997년도 춘계학술발표회논문집(1)
• /
• pp.213-218
• /
• 1997

The RTD Bypass Loops at Kori Unit 3&4 will be removed and a new system will be designed and will be installed to replace it. The replacement system provides equal or better performance and eliminates some Persistent problems. The Resistance Temperature Detector (RTD) bypass line is eliminated to reduce the radiation exposure to operators and workers. After the elimination, the resistance temperature detectors are installed in scoop of the reactor coolant piping to detect a representative temperature. This study includes safety evaluation, RTD response time Analysis, Uncertainty Analysis, LOCA evaluation and Structural Analysis.

• 한국자동차공학회논문집
• /
• 제19권5호
• /
• pp.1-6
• /
• 2011

This paper proposes a new design method for electric scooter which can maximize the power efficiency at the given driving condition. The proposed method is designed with the electric and mechanical parameters and driving dynamics. These values are extracted from the dynamic and mathematical equations of the scooter. For validation, numerical simulation results are presented in this paper. As a result, the scooter achieved over 80% efficiency at 360 rpm at 1.42kw load. It is clear that the proposed method was verified through a 1.42kw numerical model.

• 한국분말야금학회:학술대회논문집
• /
• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
• /
• pp.810-811
• /
• 2006

Pulsed Current Sintering (PCS) process possesses some problems that need to be resolved. We, therefore aims at understanding phenomena of PCS process by presenting some basic data on in situ sintering behavior of PCS. Special graphite mold equipped with thermo couple and electrodes were designed to measure the temperature, electric current and voltage inside the powder during PCS process. We apply three types of raw materials, especially for ZnO as semiconductor, $Al_2O_3$ as non-conductor and WC as good conductor. The electric current and voltage were measured for each powder during PCS process. In addition, their electric resistance properties were calculated.

• KEPCO Journal on Electric Power and Energy
• /
• 제2권1호
• /
• pp.55-59
• /
• 2016

In Europe, polypropylene-insulated HV class cable with high temperature and no cross-linking was commercialized following the MV class. Our company also started a study of the polypropylene-insulated cable in 2013 and was carried out thermal, physical and electrical test. In addition, polypropylene-insulated cable was tested for compatibility with conventional joints and terminations in emergency condition and the accelerated life test for verifying their design life is in progress. The results of this study will be used to establish a standard specification and operation conditions of the polypropylene-insulated cable.

• 한국재료학회지
• /
• 제9권1호
• /
• pp.30-34
• /
• 1999

A polyacrylonitrile(PAN)-based carbon fiber tow was heat-treated by directly passing electric current through the tow. The effects of the stretching stress applied during high temperature heat-treatment of PAN-based carbon fibers were investigated by measuring the electric resistance changes taking place during the internal resistance heating. The structure parameters characterizing the stacks of carbon layer, such as interlayer spacing, sizes and orientation of the carbon fibers heat-treated with hot-stretching were evaluated as a function of surface temperature of tow during heat treatment in the range of $1000~2400^{\circ}C$. Though the layer extent in the fiber axis direction depends strongly on the electric resistance, the changes in a crystallite parameter is independent of the longitudinal strain.

• 조명전기설비학회논문지
• /
• 제27권7호
• /
• pp.82-88
• /
• 2013

IEC standards do not require to limit the earthing resistance of the concrete-embedded foundation earthing electrode which is installed to a specific value. However, in Korea the value of $5{\Omega}$ and below applies to the earthing resistance for a domestic customer whose receiving voltage is 22.9kV. This paper calculates the minimum area and volume of the concrete-embedded foundation earthing electrode in order to obtain a specific value of the earthing resistance when the electrode of the building's lightning protection system and that of its power system are interconnected. It also suggested the most appropriate method of installing the foundation earthing electrode, taking the electric characteristics of concrete into account.

• 대한용접접합학회:학술대회논문집
• /
• 대한용접접합학회 2006년 추계학술발표대회 개요집
• /
• pp.120-122
• /
• 2006

This study deals with characterizations of microstructure and wear performance of a cladding layer, product on 1.9 mm-thick mild steel plate by the electric resistance welding, of composite metal powder of Coarse WC-6.5%Co and high carbon alloy(SHA). The cladding layer was examined and tested fur microstructural features, chemical composition, hardness, wear performance and wear mechanism. The cladding layer have two different matrix were observed by an optical microscope and EPMA. The one was the coarse WC-6.5Co structure. The other was the melted SHA with surrounding the WC-6.5Co structure. The hardness of WC-6.5Co was 1210HV. The hardness of SHA was 640HV. In comparison by wear rate, the cladding layer showed the remarkable wear performance that was 15 times of SM490 and about 62% of D2.

• 동력기계공학회지
• /
• 제11권3호
• /
• pp.41-46
• /
• 2007

The microstructure and electrochemical analysis of welds of electric resistance welding(ERW) pipe were investigated. The direction of metal flow line in HAZ of ERW pipe shifted to the inner(or outer) surface of pipe by plastic deformation during welding. The lowest heat input welds of ERW pipe was showed crack by liquid penetrant testing. Accelerated corrosion test by constant current density of 20mA/$cm^{2}$ developed groove at the welds of ERW pipe and the measured grooving factors were about $1.2{\sim}1.5$. Corrosion potential of base metal obtained by cyclic polarization in artificial sea water(3.5wt.% NaCl solution) was 100mV higher than that of weld metal of ERW pipe.

• 한국초전도학회:학술대회논문집
• /
• 한국초전도학회 2000년도 High Temperature Superconductivity Vol.X
• /
• pp.252-256
• /
• 2000

We investigated resistance development in Au/YBCO thin film meander lines during quench. The meander lines were fabricated by coating YBCO films insitu with a gold layer and patterning them by photolithography. The center stripe quenched fastest even though the flux flow resistance that appeared upon the current passing the critical current was uniform. Quench started at an area of the center stripe and propagate both through the gold layer and the sapphire substrate. Quench propagation speed was uniform and 60 cm/s at 30 V$_{rms}$.