• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.290-293
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• 2002

For small capacity rectifier circuits such as these for consumer electronics and appliances, capacitor input type rectifier circuits are generally used. Consequently, various harmonics generated within the power system become a serious problem. Various studies of this effect have been presented previously. However, most of these employ switching devices, such as FETs and the like. The absence of switching devices makes systems more tolerant to over-load, and brings low radio noise benefits. We propose a power factor connection scheme using a LC resonant in commercial frequency without switching devices. In this method, It makes a sinusoidal wave by widening conduction period using the current resonance in commercial frequency, Hence, the harmonic characteristics can be significantly improved, where the lower order harmonics, such as the fifth and seventh orders are much reduced. The result are confirmed by the theoretical and experimental implementations.

• Proceedings of the KWS Conference
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• 2005.11a
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• pp.171-173
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• 2005

Inconel 617 is a solid solution, nickel-chromium-cobalt-molybdenum alloy with an exceptional combination of high temperature strength and oxidation resistance. The combination of high strenth and oxidation resistance at temperatures over $1800^{\circ}F$ makes Inconel 617 an attractive material for such components as ducting, transition liners in both aircraft and gas turbine. In this study, the weldability and weldment characteristics of Inconel 617 are considered in GTAW associated with the two welding current and with back shielding gas using or not. After GTAW with 120A and 150A current, microstructures and hardness test, bending test, tensile test on room and elevated temperature for the determination of optical welding condition.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.10
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• pp.120-125
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• 2006

In contrast to the conventional trigatron switch in which the currents are constricted by the z-pinch mechanical the new switch operates in an inverse pinch geometry formed by a pair of spiral electrodes in a sealed-off type. Inverse pinch switch greatly reduces hot spot formations and protects the electrode surfaces. The switch can be initiated with an electrical trigger electrode. Advantages of the new switch over the conventional switches are longer useful life, high current capability and lower inductance due to the dispersed and moving current sheet. These improved characteristics may make the inverse pinch switch suitable for pulse power systems.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2019-2021
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• 1999

In this paper, the AC-PDP's structural defects with a gap between front and rear glass are investigated. Breakdown voltage, sustain voltage, current and brightness have been measured for various gaps between two plates under various gas pressures. The experimental results show that the firing voltage, sustain voltage and brightness were decreased whereas the discharge current was increased as the gap increased. When the gap is over $40{\mu}m$, it was impossible to drive cells separately.

• Journal of the Semiconductor & Display Technology
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• v.4 no.4 s.13
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• pp.5-8
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• 2005

In this study, we prepared the ITO thin film for TOLED(Top-emitting OLED) or flexible display at room temperature using the FTS(Facing Targets Sputtering Apparatus). We observed characteristics of deposited thin films as a function of sputtering conditions. XRD patterns were independence trom oxygen gas flow and input current. But electrical and optical properties were strongly dependence. In the results, we could prepare good properties of ITO thin films resistivity of $4.27X10^{-4}[\Omega-cm]$, transmittance of over 80% at working gas pressure 1[mTorr], input current 0.6[A], oxygen gas ratio 0.3[sccm], at room temperature.

• JSTS:Journal of Semiconductor Technology and Science
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• v.4 no.2
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• pp.124-127
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• 2004

W/n-GaN Schottky diodes were irradiated with $^{60}Co\;{\gamma}-rays$ to doses up to 315Mrad. The barrier height obtained from current-voltage (I-V) measurements showed minimal change from its estimated initial value of ${\sim}0.4eV$ over this dose range, though both forward and reverse I-V characteristics show evidence of defect center introduction at doses as low as 150 Mrad. Post irradiation annealing at $500^{\circ}C$ increased the reverse leakage current, suggesting migration and complexing of defects. The W/GaN interface is stable to high dose of ${\gamma}-rays$, but Au/Ti overlayers employed for reducing contact sheet resistance suffer from adhesion problems at the highest doses.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.12
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• pp.12-20
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• 1998

The non-uniform leaky wave structure of the slits in a parallel-plate waveguide is analyzed from the viewpoints of transmitting(receiving) leaky wave antenna and grating coupler. Period and slit width are simultaneously varied along the leaky wave structure to construct the leaky wave structure with a specific distribution of complex propagation constant. Some results for the equivalent magnetic current distributions over the slits and the radiation characteristics of the leaky wave structure with various source(equivalent magnetic current) distributions such as Gaussian, uniform, cosine, cosine-squared, and Taylor distributions are given and compared with each other.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.11a
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• pp.321-326
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• 2005

Interior permanent magnet synchronous motor(IPMSM) has become a popular choice in electric vehicle applications, due to their excellent power to weight ratio. The paper is proposed maximum torque control of IPMSM for high speed drive. The control method is applicable over the entire speed range and considered the limits of the inverter's current and voltage rated value. For each control mode, a condition that determines the optimal d-axis current $^i{_d}$ for maximum torque operation is derived. The proposed control algorithm is applied to IPMSM drive system for high speed drive, the operating characteristics controlled by maximum torque control are examined in detail by experiment.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.11a
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• pp.309-314
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• 2005

The paper is proposed maximum torque control of SynRM drive using learming mechanism-fuzzy neural network(LM-FNN) controller and artificial neural network(ANN). The control method is applicable over the entire speed range and considered the limits of the inverter's current and voltage rated value. For each control mode, a condition that determines the optimal d-axis current $^i{_d}$ for maximum torque operation is derived. The proposed control algorithm is applied to SynRM drive system controlled LM-FNN and ANN controller, the operating characteristics controlled by maximum torque control are examined in detail. Also, this paper is proposed the analysis results to verify the effectiveness of the LM-FNN and ANN controller.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.258-261
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• 2001

In this paper, aging characteristics of silicone rubber used for outdoor insulation have been investigated with regards to salt fog condition and heat aging effect. We look over the change of properties of silicone rubber in salt fog chamber with average leakage current monitoring for observing the transformation of surface degradation properties of silicone rubber with different ATH(alumina trihydrate, Al$_2$O$_3$$.$3H$_2$O) filler contents. Surface resistivity, SEM(Scanning Electro Microscope) were measured.