• Journal of Mechanical Science and Technology
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• v.16 no.8
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• pp.1117-1126
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• 2002

A conducting crack in an electrostrictive ceramic under combined electric and mechanical loading is investigated. Analysis based on linear dielectric model predicts that the surfaces of the crack are not open completely but they are contact near the crack tip. The complete solution for the crack with a contact zone in a linear electrostrictive ceramic under combined electric and mechanical loading is obtained by using the complex variable formula. The asymptotic problems for a semi-infinite crack with a partial opening zone as well as for a fully open semi-infinite crack in a nonlinear electrostrictive ceramic are analyzed in order to investigate the effect of the electrical nonlinearity on the stress intensity factor under small scale nonlinear conditions. Particular attention is devoted to a finite crack in the nonlinear electrostrictive ceramic subjected to combined electric and mechanical loading. The stress intensity factor for the finite crack under small scale nonlinear conditions is obtained from the asymptotic analysis.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.219-222
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• 2007

The Full-Off Fitting of Movable Bracket using conventional line have received a dynamic contact impact between contact wire and pantograph of electric rolling stock, so this impact cause a rapid vibration of foreword and back near the supporting point of movable bracket. The Full-Off Fitting on Movable Bracket in conventional line differs from that in high speed line. Now conventional line have required a speed up for new electric locomotive and electric car. In speed-up track and big impact place, the Full-Off Fitting and the dropper often get demage. We have done a study of buffering function to solve that problem in conventional line. We have find a need adopting buffer fitting. It is decrease a dynamic impact between contact wire and pantograph of electric rolling stock.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.5
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• pp.307-311
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• 2016

Although there are existing Residual Current Protective Device (RCD) including detect electric leakage and elements such as short circuit and surge, the occurrence of incidents caused by electric faults, including fire, are still constant. The purpose of this study is to analyze the causes of accidents through the electric field distribution in the interpretation of the fault contact breaker. Simulation results by the arc fault has shown the convergence of temperature and electric field to the defect. Through their simulation results, the main cause of erosion phenomena in circuit breaker bar is the electric arc by concentration of electric field not due to dissolve by temperature.

• Korean Journal of Materials Research
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• v.24 no.3
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• pp.135-139
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• 2014

To obtain the transistor with ambipolar transfer characteristics, IGZO/SiOC thin film transistor was prepared on SiOC with various polarities as a gate insulator. The interface between a channel and insulator showed the Ohmic and Schottky contacts in the bias field of -5V ~ +5V. These contact characteristics depended on the polarities of SiOC gate insulators. The transfer characteristics of TFTs were observed the Ohmic contact on SiOC with polarity, but Schottky contact on SiOC with low polarity. The IGZO/SiOC thin film transistor with a Schottky contact in a short range bias electric field exhibited ambipolar transfer characteristics, but that with Ohmic contact in a short range electric field showed unipolar characteristics by the trapping phenomenon due to the trapped ionized defect formation.

• Proceedings of the KIEE Conference
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• 1998.07e
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• pp.1614-1616
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• 1998

Insulation performance of major components of prefabricated joint such as epoxy insulation unit and premolded rubber cone are guaranteed by material selection design and proper manufacturing. On the other hand insulation performance of the interfaces between the premolded rubber cone and the epoxy insulation unit and the cable insulation is maintained by keeping the premolded rubber cone to close contact with such insulation by spring. Electric characteristics of a interface depend on the contact pressure, but the required characteristics are assured so far as a proper contact pressure is maintained. In this report, the interfacial pressure by pressure sensors both in the early stage and after heating cycle were measured and the simulation by FEM program were presented. The comparison of these two results show that interfacial pressure could be controlled optimally by changing the spring length and lubricant state of the interface.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.6
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• pp.507-511
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• 2019

The purpose of an electric railway system contact wire is to supply electric energy to trains through a contacted pantograph. This energy is then converted into mechanical energy. Recent developments in overhead contact lines include the increase in the tension force up to 34 kN according to train speeds that reach up to 400 km/h with a verified safety. Rigid conductor catenary (R-Bar) for high speeds of up to 250 km/h have been developed in tunnels to save on construction costs. This is significant because minor defects in R-bars in aspects, such as height and stagger affect installation conditions. In this study, we propose the use of a detector that measures the static characteristics to reduce the R-bar installation errors. This detector has been developed to measure the height and stagger of the contact wire using video images.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.3
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• pp.351-356
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• 2009

In this study, we analyzed and experimented about electric continuity for human body safety from green cars. And we compared power systems of HEV and examined about human body effect of current and time. We investigated internal and external standards and regulations for human body safety from high voltage electrical equipments. Indirect contact refers to contact between the human body and exposed conductive parts. According to UNECE R100, ISO 23273-3, ISO 6469-3 and Japanese Regulation Attachment 101, electric continuity between any two exposed conductive parts shall not exceed $0.1{\Omega}$. The value of electric continuity was measured below $0.1{\Omega}$ at the actual condition of green car. We expected that the results of these experiments can utilize to data for electrical safety of green car.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.1
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• pp.51-56
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• 2015

This paper presents an investigation of abnormal wear of a contact jig between a nail and a nail fixture in electric resistance welding. To perform an analysis on the abnormal wear phenomenon, several methods are provided. Based on the theory of electric resistance welding, are analyzed. Using microscopic analysis, surface craters are observed. In the measurement of the electric current flow in the nail fixture, the current flow distribution is measured. From several analyses, the cause of abnormal wear in the contact jig is measured using the electric discharge of high current density at the inflow point of the electric supply to the nail fixture. An alternative shape for normal wear is proposed.

• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.235-240
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• 2009

Crystlline silicon solar cells markets are increasing at rapid pace. now, crystlline silicon solar cells markets screen-printing solar cell is occupying. screen-printing solar cells manufacturing process are very quick, there is a strong point which is a low cost. but silicon and metal contact, uses Ag & Al pates. because of, high contact resistance, high series resistance and sintering inside process the electric conductivity decreases with 1/3. and In pastes ingredients uses Ag where $80{\sim}90%$ is metal of high cost. because of low cost solar cells descriptions is difficult. therefore BCSC(Buried Contact Solar Cell) is developed. and uses light-induced plating, ln-line galvanization developed equipments. Ni/Cu matel contact solar cells researches. in Germany Fraunhofer ISE. In order to manufacture high-efficiency solar cells, metal selections are important. metal materials get in metal resistance does small, to be electric conductivity does highly. efficiency must raise an increase with rise of the curve factor where the contact resistance of the silicon substrate and is caused by few with decrement of series resistance. Ni metal materials the price is cheap, Ti comes similar resistance. Cu and Ag has the electric conductivity which is similar. and Cu price is cheap. In this paper, Ni/Cu/Ag metal contact cell with screen printing manufactured, silicon metal contact comparison and analysis.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.4
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• pp.427-431
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• 2009

In this study, the dynamic characteristic of a contact wire and pantograph suppling electrical power to high-speed trains are investigated from an electrical response point of view. To analysis power line disturbance by induced contact loss phenomenon for high speed operation, a hardware Simulator which considered contact loss between contact wire and the pantograph as well as contact wire deviation is developed. It is confirmed that a contact wire and pantograph model are necessary for studying the dynamic behavior of the pantograph system. One of the most important needs accompanied by increasing the speed of high-speed train is reduced that an arc phenomenon by loss of contact brings out EMI. In case of a high-speed train using electrical power, as comparison with diesel rolling stock, PLD(Power Line Disturbance) such as harmonic, transient voltage and current, EMI(Electromagnetic Interference), dummy signal injection etc usually occurs. Throughout experiment, it is verified that an arc phenomenon is brought out for simulator operation and consequently conducted noise is flowed in electric circuit by power line disturbance.