• Textile Coloration and Finishing
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• v.25 no.3
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• pp.232-239
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• 2013

In this study, 25gsm melt-blown polypropylene nonwoven for dust-proof/medical masks was finished by the corona discharging treatment. The influence of corona discharging parameters on the filtration efficiency was investigated. Several parameters such as discharging voltage, discharging speed, distance to discharging wire and configuration of discharging system had an effect on filtration efficiency, while the parameters had no effect on breathing resistance. Optimum corona discharging conditions are as follows: Wires were installed on the upper part of the nonwoven and paper pipe was installed on the lower part of the nonwoven having a distance of 5cm. The sequence of wire voltages was +60 kV, +60 kV, 0, -60 kV, and -60 kV. The discharging voltage and speed were 60 kV and 30m/min respectively. The nonwoven treated by corona discharging at the optimum condition showed a filtration efficiency of 80% or more, which is suitable for dust-proof/medical masks.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.10
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• pp.2005-2010
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• 2009

Water droplet ejection characteristics of a point-to-plate airgap, with a wet porous point as a corona electrode, has been investigated. And the water droplet traces, charge, mass and number were measured experimentally. More particles are observed with wet porous point than metal point because the corona-discharging wet porous point can eject a number of water droplets. The water droplets ejected from the positive-corona-discharging wet porous point showed very fine traces as compared with those from the negative-corona-discharging wet porous point. Moreover, the water droplets ejected from the AC-corona-discharging wet porous point showed granular-like larger traces. It was shown that the weak corona discharge can eject smaller water droplets with larger ratio of mass-to-charge than the intense corona discharge.

• Electrical & Electronic Materials
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• v.8 no.3
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• pp.316-323
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• 1995

A vital step in magnetic tape manufacturing is the surface modification of polymer substrate prior to ink application. A critical element for good adhesion of magnetic ink on polymeric substrate is the ability to join ink in cost-effective manner. Corona discharging is one of the effective methods of modifying polymer surface to improve adhesion while maintaining the desirable properties of the film itself. Surface treatment by corona which is exposure of film surface to electron or ion bombardment, rather than mere exposure to active species, like atomic oxygen or ozone, can enhance adhesion by removing contaminant, electret, roughening surface, and/or introducing reactive chemical groups. Reactive neutrals, ions, electron and photons generated during the corona treatment interact simultaneously with polymers to alter surface chemical composition, wettability, and thus film adhesion. However, it is highly recommended that extensive chains scission be avoided because it can lead to side-effect by forming sticky matter, resulting in dropouts. This paper reviews principles of surface preparation of polymer substrate by corona discharging. In addition, the experimental section provides a description of parameter optimization on corona discharging treatment and its side-effect. Experimental results are discussed in terms of surface wetting as determined by contact angle measurements.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.4
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• pp.158-163
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• 2002

The pulsed Power system has been widely used to many applications, such as E/P(Electrostatic Precipitator), DeNOx/DeSOx power system, often generator, etc. In this paper, we study EMTP analysis and characteristics of critical voltage and load in impedance on various electrode length of pulse corona. To obtain a stable pulse voltage, we designed a compact pulse generator switched MOSFET and tested their characteristics by adjusting electrode length and pulse repetition. As a re sult, critical voltage of pulse corona and load impedance on increasing electrode length were decreased. These results indicate we can control critical voltage of pulse corona and suppress arc discharging between two electrodes.

• Journal of the Korean Society of Safety
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• v.33 no.1
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• pp.41-46
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• 2018

Experiments were carried out the phenomenal observation on effect of corona treated hotmelt laminating film in process of manufacture by 2 kinds of rolling speed and electric power variatons. Surface treatment by corona which is exposure of film surface to electron of ion bombardment, rather than mere exposure to active species, like atomic oxygen or ozone, can enhance adhesion by removing contaminant, electret, roughening surface, and introducing reactive chemical group. Reactive neutrals, ions, electron and photons generated during the corona treatment interact simultaneously with polymers to alter surface chemical composition, wettability, and thus film adhesion. However, it is highly recommended that extensive chains scission is avoided because it can lead to side-effect by forming sticky matter, resulting in dropouts. This paper reviews principles of surface preparation of polypropylene substrate by corona discharging. In addition, the experimental section provides a description of parameter optimization on corona discharging treatment and its side-effect. Experimental results are discussed in terms of surface wetting as determined by contact angle and SEM measurements. When the rolling speed of the film decreased from 1.666 [m / sec] to 0.083 [m / sec], contact angle decreased from $80[^{\circ}]$ to $64[^{\circ}]$, and the wettability was greatly improved. As the supply power increased from 0.4 [kVA] to 2 [kVA] at the corona discharge surface treatment, the contact angle decreased from $77[^{\circ}]$ to $65[^{\circ}]$, and the wettability was greatly improved.

• Journal of the Korean Society of Safety
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• v.7 no.2
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• pp.57-62
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• 1992

In this thesis, the electrification phenomenon was studied by measurement of charging current and discharging current in polymers when the carriers generated by corona discharge were supplied to the surface of polymers. Corona charging current of PVC, polar and noncrystalline polymer, was larger than that of nonpolar and amorphous polymers. Corona charging current on the specimen of naked upper surface (CIM) was larger than charging current on the specimen of electrode made. Carrier injection differed from interfacial phase of polymer surFace. The transfer phenomenon vaned with chemical structure of polymer and then the polar effect of PVC was remarkable because of large electron affinity of Cl. In the characteristics of discharging current of PVC, the abnormal current was observed. It was supposed that this phenomena presented the trap of injected carriers in PVC and that static electricity phenomenon was generated by trap.

• Journal of the Korean Society of Safety
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• v.29 no.6
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• pp.46-48
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• 2014

This paper compared and demonstrated the performance of the earth plate for conventional type and early streamer discharging type developed a new plate in order to improve the performance of the ground plate for use in grounding. The results obtained are shown below; early streamer discharge earth plate was high 5 kV on DC flashover voltage and corona discharge current was higher than about 2 times under the same test conditions compared to the conventional earth plate. From the experiential result, streamer discharge earth plate had a function of rapid inflow/out flow than the general ground plane because of by corona discharge current to be generated in the sharp serrated in formed the ground plane when strike current occurred. In the future, the newly developed early streamer discharge ground plate would be beneficial for grounding work to be widely used to promote the convenience and economy of construction.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.11a
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• pp.365-368
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• 1995

Charge decay, thermally stimulated current (TSC), charging and discharging currents(I) are measured for corona-charged composite insulating materials. In this study, We will make an experiment in charge decay on composite material surface, TSC, polarity effect and the others in order to analysis its mechanism. Especially, Fiber glass Reinforced Plastics(FRP) is the best composite material which has been so far. Therefore, Its worthy of notice to investigate its characteristic. And then some other materials will be focused on. This experiment measured characteristic of charge decay, dependence of discharging-time and other electrostatic characteristics on FRP.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.602-606
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• 2006

The electrostatic is well known phenomena. The fires and explosions caused by electrostatic occur often in the coating mechanical system. This paper presents various cases of electrostatic hazards, reasons why electrostatic hazards are happened, and methods for preventing electrostatic hazards. Generally the electrostatic can be lead to corona discharging, streaming electrification, and impinging electrification in the coating process. Corona discharging happens at electrostatic spray gun with 70 kV. Streaming electrification occurs at mixing process between paint and thinner, and transportation process with thinner. Impinging electrification is shown when the thinner are sprayed to drums. For the purpose of preventing the electrostatic discharge and damage, conductors should be ground, surface electric potential of should be decreased in using electrostatic shielding and ground, and flow of thinner should be controlled acceptable velocity.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.9
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• pp.69-74
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• 2011

In this paper, the UV corona camera was developed using the solar blind and Multi Channel Plate(MCP) technology for the target localization of UV image. UV camera developed a $6.4[^{\circ}]{\times}4.8[^{\circ}]$ of the field of view as a conventional camera to diagnose a wide range of slightly enlarged, and power equipment to measure the distance between the camera and the distance meter has been attached. UV camera to measure the discharge count and the UV image was developed, compared with a commercial camera, there was no significant difference. In salt spray environments breakdown voltage was lower than the normal state, thereby discharging the image was rapidly growing phenomenon.