• Particle and aerosol research
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• v.9 no.1
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• pp.31-36
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• 2013

In this study, Mo metal powder was prepared by hydrogen reduction of Mo trioxides with different purity of 2N and 3N grades. We have obtained Mo metal powder with oxygen content of 1450 ppm by hydrogen reduction and subsequent heat treatment for degassing. Using the Mo metal powder, a low-oxygen Mo ingot was prepared by repetitive vacuum arc melting. The oxygen content of the obtained Mo ingot was less than 70 ppm after vacuum arc melting for 30 min. The purity of the Mo metal powder and the ingot was evaluated using glow discharge mass spectrometry. The purity of the respective Mo ingots was increased to 3N and 4N grades from the Mo powder of 2N and 3N grades after the repetitive vacuum arc melting. The low oxygen Mo ingot thus can be used as a raw material for sputtering targets.

• Journal of the Korean institute of surface engineering
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• v.43 no.2
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• pp.80-85
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• 2010

The surfaces of WC-Co and SCM415 were etched to form a micro size protrusion for oil based ultra low friction applications using an ion bombardment process in a filtered vacuum arc plasma. WC-Co species showed that a self-patterned surface was available by the ion bombarding process due to the difference of sputtering yield of WC and Co. And the increasing rate of roughness was 0.6 nm/min at -600 V substrate bias voltage. The increasing rate of roughness of SCM415 species was 1.5 nm/min at -800 V, but the selfpatterning effect as shown in WC-Co was not appeared. When the SCM415 species pretreated by electrical discharge machining is etched, the increasing rate of roughness increased from 1.5 nm/min to 40 nm/min at -800 V substrate bias voltage and the uniform surface treatment was available.

• Nuclear Engineering and Technology
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• v.56 no.1
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• pp.70-77
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• 2024

A low energy ion irradiation system based on the deuterium arc ion source with a high perveance of 1 µP for a single extraction aperture has been successfully developed for the investigation of ion irradiation on plasma-facing components including the first mirror of plasma optical diagnostics system. Under the optimum operating condition for mirror testing, the ion source has a beam energy of 200 eV and a current density of 3.7 mA/cm². The ion source comprises a magnetic cusp-type plasma source, an extraction system, a target system with a Faraday cup, and a power supply control system to ensure stable long time operation. Operation parameters of plasma source such as pressure, filament current, and arc power with D₂ discharge gas were optimized for beam extraction by measuring plasma parameters with a Langmuir probe. The diode electrode extraction system was designed by IGUN simulation to optimize for 1 µP perveance. It was successfully demonstrated that the ion beam current of ~4 mA can be extracted through the 10 mm aperture from the developed ion source. The target system with the Faraday cup is also developed to measure the beam current. With the assistance of the power control system, ion beams are extracted while maintaining a consistent arc power for more than 10 min of continuous operation.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.1391-1393
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• 2002

There arc some problems on storage batteries which are called Secondary Battery, such as long charging time, limited cycle life, low coulomb efficiency and inaccurate residual power meter. To solve those problems, a complex system of capacitors and Super Capacitors of increased energy density. Though the capacitors alone arc not capable of delivering stable output, the accompanied circuits compensate the various characteristics all through the charge-and discharge-cycle. This paper deals with Energy Storage System with Super Capacitor for PV System Discussed in this paper are, explains the accompanied circuits of Super Capacitor which is compared with the Second Batteries.

• Journal of the Korean institute of surface engineering
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• v.35 no.3
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• pp.121-126
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• 2002

WC/C multilayered films were deposited by arc ion plating and magnetron sputter hybrid system with various $C_2$H$_2$ flow rates and bias voltages. The coatings have been characterized with respect to their chemical composition (Glow Discharge Optical Emission Spectroscopy), hardness(Knoop micro-hardness), residual stress(Laser beam bending) and friction coefficient(Ball on disc type wear test). Deposition rate, microhardness and residual stress of WC/C films were observed to increase with increasing the $C_2$$H_2$ flow rates. The highest hardness and residual stress were measured to be 26.5 GPa and 1.1GPa for, WC/C film deposited at substrate bias of -100V. WC/C multilayered film was obtained very low friction coefficient(~0.1).

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1623_1624
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• 2009

The use of arc tubes made of ceramic material further enhanced some of the metal halide lamp’s properties. These properties translate into higher efficacy with better color rendering, stable color through lamp long life. Recently, due to an increase in the application of the ceramic metal-halide lamp, the study for the property etc. according to Ballast's driving scheme and the study for arc tube material, optimization of gas and so on are being proceeded to improve the property of the lamp. Especially, to control ceramic metal-halide lamp, the vigorous study and practical use with respect to Electronic Ballast, which has been improved in the disadvantages of the conventional Magnetic Ballast are made. In this paper, Electrical characteristics and gas insulation destroy time are analyzed by comparing magnetic ballast with electronic ballast.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.35 no.11
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• pp.495-502
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• 1986

The change of the discharge characteristics of the high-pressure sodium (HPS) lamps is investigated over a power source frequency range of 60 Hz to 30, 000 Hz. As the frequency increases, the light and electrical characteristics of the HPS lamps are improved since the re-ignition is not needed due to the constant electron density, and the cathode fall is reduced. But at the certain frequency range, the arc instability called acoustic resonance occurs, and the arc tube is damaged. Regarding these characteristics and the kind of the illuminating system, a proper frequency is selected to operate the HPS lamps. And a new measuring system using a computer and the storage-scope is developed to avoid the error of the ordinary gauges at high frequency power.

• Journal of Industrial Technology
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• v.20 no.B
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• pp.169-174
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• 2000

The most of metalhalide lamps is what the momentary restarting cannot be realized when the arc tube is in the hot condition. The discharge starting voltage of arc tube in the hot condition is much higher than in the cold condition in proportion to the gaseous pressure. Therefore it takes about ten minutes to restart the metal Halide lamps, that is to say, it is possible to start when the pressure and the temperature are decreased. But, if the lamp is restarted in the hot condition, we must supply the high voltage pulse with 15kV between the both electrodes of lamp. The proposed ignitor has two ignitors. If we connect each ignitor at the both sides, the high voltages of two different frequencies are generated. If so, when the one of the ignitor generates the highest voltage and the other applied to elecrodes of the lamp. In this way, we can restart the lamp with the voltage 15kV, even if the lamp is in the hot condition.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.2
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• pp.28-33
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• 2007

In this paper, we are studied on the direction and formation of carbonized conductive path according to surface leakage current between electrodes. The characteristics of the tracking as surface is broken down between exposed live parts. Using the HSIS(high speed imaging system. 100,000[fps], redlake ltd., USA), it took photographs by arc growth mechanism occurred in on/off surge, ground fault and discharge between electrodes. Then the results was analyzed. Hereafter, it expected effects that application of energy utility technology through the arc control.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2003.11a
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• pp.185-190
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• 2003

The most shortcoming of metalhalide lamps is what the instant restarting cannot be realized when the arc tube is in the hot condition. The discharge starting voltage of arc tube in the hot condition is much higher than in the cold condition. Therefore it takes about five minutes to restart the metalhalide lamps, that is to say, it is possible to start when the pressure and the temperature are decreased. But, if the lamp is restarted in the hot condition, we must supply the high voltage pulse with 20kV at the both sides of lamp. The proposed electronic ballast is consist of a electromagnetic interference (EMI) filter, a power factor correction (PFC) circuit, a flyback converter, a half-bridge inverter, and a high voltage igniter circuit. By this composition we can restart the lamp with the voltage 20kV, even if the lamp is in the hot condition.