• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.11a
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• pp.152-155
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• 1994

The purpose of this paper is to develope an electron beam resist by the plasma polymerization. Plasma co-polymerized resist was prepared using an interelectrode gas-flow-type reactor. And then delineated pattern in the resist was developed with gas flow type reactor using Ar and O$_2$ gas as etching gas. We study about the effects of discharge power and mixing rate of the copolymerized thin film. The characteristics of molecular structure of thin film was investigated by FT-lR, DSC and GPC, and then was discussed in relation to its quality as a resist.

• Laser Solutions
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• v.5 no.3
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• pp.15-20
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• 2002

The principal obstacle to selection of a laser processing method in production is its relatively high equipment cost and the natural unwillingness of production supervision to try something new until it is thoroughly proven. The major objective of this work is focused on the combined features of gas tungsten arc and a low-power cold laser beam. In this work, the laser beam from a 7 watts carbon monoxide laser was combined with electrical discharges from a short-pulsed capacitive discharge GTA welding power supply. When the low power CO laser beam passes through a special composition shielding gas, the CO molecules in the gas absorbs the radiation, and ionizes through a process blown as non-equilibrium, vibration-vibration pumping. The resulting laser-induced plasma(LIP) was positioned between various configurations of electrodes. The high-voltage impulse applied to the electrodes forced rapid electrical breakdown between the electrodes. Electrical discharges between tungsten electrodes and aluminum sheet specimens followed the ionized path provided by LIP. The result was well-focused melted spots.

• Proceedings of the KIEE Conference
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• 1997.07e
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• pp.1721-1723
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• 1997

In AC Plasma Display Panel(PDP), serious problems are low radiation brightness and very high discharge voltage. To solve these problems, it is necessary to obtain optimal frequency of drive waveform and optimal gas mixing ratio. This paper presents firing voltage and sustain voltage as frequency of waveform and gas mixing ratio, and proposes optimal frequency of drive waveform and optimal gas mixing ratio.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.8
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• pp.343-349
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• 2005

The gas in oil analysis of transformer is the most widely used technology for diagnosis of transformer in the world. It has brought excellent results to prevention of transformer failure. The criteria for maintenance and judgement, however, is still required continuous supplement to improve the accuracy of the diagnosis on the basis of accumulated data of gas analysis and investigations in the transformer In this study, the relationship between the detection rate of the defects and the source of troubles are analyzed according to the investigation in the transformer, which was conducted by KEPCO in 2004. As a result, the validity of the criteria being used at present was examined thoroughly.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.34 no.7
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• pp.289-296
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• 1985

The Townsend primary ionization coefficient a was measured by the luminous-flux method using the fact that the intensity of radiant light is proportional to electron density in the townsend discharge domain. The ranges of measurements were 15for He gas and 10

• Journal of the Korean Society of Safety
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• v.8 no.4
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• pp.120-126
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• 1993

This work was carried out to investigate the effects of solid mass flow rate, mean particle diameter and mesh number of screen packing material on minimum carrying velocity, which defined as the superficial gas velocity of the upper limit of chocking phenomenon. Vertical pneumatic conveying was studied on a 4.6cm 1. D. pipe, 180cm in length. Experiments were performed in both the empty and the screen-packed pipe. It was also examined the effect of superficial gas velocity, solid mass flow, mean particle diameter, and mesh number of packing material on pressure drop. Minimum carrying velocity in screen packed-pipe was lower than that in an empty pipe. besides minimum carrying velocity was decreased with increase in mesh number of screen packing material. The pressure drop In vortical packed-pipe was Increased with superficial gas velocity, mean particle diameter, and mesh number of screen packing material.

• Journal of the Korean Society of Safety
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• v.23 no.5
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• pp.15-21
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• 2008

The bus using compressed natural gas(CNG) trend to be extended in use internationally as optimal counter-plan for reducing discharge gas of light oil due to high concern about environment. But, Composit pressure vessels(CPV) to be equipped with CNG bus is always involved in the point that safety accidents happen due to having compressed natural gas. In this report, we analysis the cause of CPV bursting accident by reviewing design and manufacture factor and suggest preventive measure through this case.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.601-604
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• 1993

The effect of an insulator inserted along the axis of a red-to-plane gap on an ion flow field in $SF_6$ gas is investigated experimentally in the pressure region where a proceeding corona discharge exists. Without the insulator, the calculated electric field on the plane electrode agrees fairly well with the measured one. With the insulator, the ion flow field characteirstics may be attributed to the change in the electric field distribution by the accumulated charge, the increase in the ratio of the dielectric strength in gas gap to that along the insulator surface with the gas pressure, and the thermal diffusion of ions near the insulator.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.1162-1165
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• 2004

In oil-filled enuipment such as transformers, partial discharge or local overheating will precede a final shutdown. Accompanied with such problems is a decomposition of insulating material into gases, which are dissolved into the transformer oil. The gases dissolved in oil can be separated with some membranes based on the differences in permeability of membranes to different gases. This paper discuss the permeability characteristics of several membranes for separation hydrogen gas in oil. With result of this paper, it may become possible to detect fault-related gases from transformer oil and predict incipient failures in the future.

• Journal of Electrical Engineering and Technology
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• v.5 no.4
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• pp.631-636
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• 2010

Gas-insulated transmission lines (GITL) are valued as technological solutions in hydro-power stations due to their enormous power handling capabilities. The performance of GITL is a function of the size of metallic particles inside the gas-insulated chamber. Electrostatic field (E-field) enhancement is a common phenomenon in gas-insulated lines due to these metallic particles. In this study, the E-field enhancement factor is calculated by considering metallic particles at various locations in the gas-insulated line/bus section, such as high-tension (HT) conductor, high-voltage shields, support insulator, and inner surface of grounded enclosure. For this purpose, a two-dimensional model based on finite element (FE) method is developed. The length of the metallic particle is in the range of 1 to 10 mm while the diameter is between 1 to 3 mm. E-field enhancement is also computed for various particle configurations of the gas-insulated system, with focus on dielectric coating made of epoxy on HT conductor and inner surface of grounded enclosure.