• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.5
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• pp.386-393
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• 2007

Charge-pump high voltage inverter for Plasma backlight using CIM(Current Injection Method) is proposed in this paper. Adoption of ERC(Energy Recovery Circuit) is a new attempt in high voltage inverter so that it is not only energy recovery but also improvement of discharge stability and system unstability which is interrupted by noise. Using a charge-pump technique enables low voltage switches to be usable, the cost can be reduced. CIM is adopted to achieve high speed energy recovery in proposed circuit. Operations of the proposed circuit are analyzed for each mode. The proposed circuit is verified to be applicable on a 32 inch plasma backlight panel by experimental results.

• Journal of Korean Society for Atmospheric Environment
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• v.12 no.4
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• pp.487-494
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• 1996

Simultaneous effects of $C_2H_4$ injection and heterogeneous chemical reactions on non-thermal plasma process to remove $SO_2$ and NOx from flue gas were investigated in the present experimental study. The present results showed that 40% of the electrical power can be reduced in $C_2H_4$ injection and heterogeneous chemical reaction are simultaneously included in the non-thermal plasma precess. As an effort to apply the non-thermal plasma technique to practical flue gas treatment system, a wire-plate type reactor which has technically similar geometry of industrial electrostatic precipitators is used instead of other types of reactors, such as wire-cylinder, packed-bed and surface discharge which are inappropriate to industrial application. In the present study, the photo pictures of positive streamer corona taken by ICCD camera, voltage and current oscillograms, and design criteria of a wire-plate type reactor are also shown, which are needed for industrial application of the non-thermal plasma process.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.262.2-262.2
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• 2014

Plasma processing is an essential process for pattern etching and thin film deposition in nanoscale semiconductor device fabrication. It is necessary to maintain plasma chamber in steady-state in production. In this study, we determined plasma chamber state with residual gas analysis with self-plasma optical emission spectroscopy. Residual gas monitoring of fluorocarbon plasma etching chamber was performed with self-plasma optical emission spectroscopy (SPOES) and various chemical elements was identified with a SPOES system which is composed of small inductive coupled plasma chamber for glow discharge and optical emission spectroscopy monitoring system for measuring optical emission. This work demonstrates that chamber state can be monitored with SPOES and this technique can potentially help maintenance in production lines.

• Transactions on Electrical and Electronic Materials
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• v.16 no.2
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• pp.95-98
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• 2015

Organic polymer dielectric thin films of styrene and vinyl acetate were prepared by the plasma polymerization deposition technique and applied for the fabrication of an organic thin film transistor device. The structural properties of the plasma polymerized thin films were characterized by Fourier-transform infrared spectroscopy, X-ray diffraction, atomic force microscopy, and contact angle measurement. Investigation of the electrical properties of the plasma polymerized thin films was carried out by capacitance-voltage and current-voltage measurements. The organic thin film transistor device with gate dielectric of the plasma polymerized thin film revealed a low operation voltage of −10V and a low threshold voltage of −3V. It was confirmed that plasma polymerized thin films of styrene and vinyl acetate could be applied to functional organic thin film transistor devices as the gate dielectric.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.161.2-161.2
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• 2015

Melanin is a black pigment, responsible for hair and skin color. In order to find the melanin stimulatory technique which prove useful for a gray and a white hair-preventive agent or tanning agent, we developed atmospheric pressure plasma jet (APPJ) and tested for tyrosinase activity and melanin production in melanoma (B16F10) cells in vitro. We found plasma dose dependent increase in melanin production. To explore the contributing mechanism in melanin synthesis, intracellular reactive oxygen species (ROS) and MAP kinase signaling pathways were studied. Furthermore, the development of plasma technology for melanin synthesis and planning for in-vivo future studies will be discussed.

• Journal of the Korean institute of surface engineering
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• v.29 no.6
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• pp.857-861
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• 1996

The influence of rf-plasma operation on the thin film formation containing small particles for Al-Li alloys mainly have been studied as a function of Ar gas pressure and plasma power by means of a 200kV transmission electron microscope (TEM). Under the non-plasma operation, the transition from continuous thin films to clusters of grape-like small particles occurred at Ar gas pressures above 20Pa. Particles were single crystals with clear crystal habit planes. Under the plasma operation, the influence of gas pressures on the film formation at a plasma power of 5W was also examined. Thin films containing particles below 30Pa and the films containing mainly particles above 40Pa were formed. The prominent change of the average particle size was not recognized. The increase of the plasma powers at 20Pa, which formed particles under non-plasma, suppressed growth of particles, and homogeneous films containing very small particles were fabricated. The electric conductivity showed slight decrease with an increase of plasma power.

• Bulletin of the Korean Chemical Society
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• v.18 no.11
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• pp.1172-1175
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• 1997

Calcium isotopic ratios are precisely measured by removing isobaric interferences originated from water in the plasma. Liquid Ar cryogenic trap combined with membrane desolvator could eliminate backgrounds at m/z 42 and 44. Slow drift of ICP-MS is corrected by the frequent running of the standards. It is found necessary to separate Ca from the sample matrix using Ca oxalate precipitation technique. Currently, the RSD is 0.5-1.0% for 2 minutes of measurement but is expected to be improved if the measurement time is increased. The technique was applied to 42Ca enriched baby fecal samples and successfully determined 42Ca/44Ca ratio changes.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.320-320
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• 2013

Film thickness monitoring with plasma impedance monitoring (PIM) is demonstrated for small area $SiO_2$ RF plasma etching processes in this work. The chamber conditions were monitored by the impedance signal variation from the I-V monitoring system. Moreover, modified principal component analysis (mPCA) was applied to estimate the $SiO_2$ film thickness. For verification, the PIM was compared with optical emission spectroscopy (OES) signals which are widely used in the semiconductor industry. The results indicated that film thickness can be estimated by 1st principal component (PC) and 2nd PC. Film thickness monitoring of small area $SiO_2$ etching was successfully demonstrated with RF plasma harmonic impedance monitoring and mPCA. We believe that this technique can be potentially applied to plasma etching processes as a sensitive process monitoring tool.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.1
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• pp.10-13
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• 2010

The plasma processing technologies of thin film deposition and surface treatment technique have been applied to many industrial fields. This study is purposed Large-area uniformity and surface treatment on the stainless substrate. We treat surface of stainless by $CF_4$ plasma. $CF_4$ plasma is generated by using SPM(Scanning plasma method)which is kind a of CVD. Generally, SPM has been used for uniform surface treatment using a crossed electromagnetic field. The optimum discharge condition has been studied for the gas pressure, the magnetic flux density and the distance between substrate and electrodes. In result, contact angle is increased by surface treatment using $CF_4$ Plasma. Therefore we expect that SPM to control contact angle is applied to many industries.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.220-220
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• 1999

In plasma source ion implantation, the target is immersed in the plasma and repetitively biased by negative high voltage pulses to implant the extracted ions from plasma into the surface of the target material. In this way, the problems of line-of-sight implantation in ion-beam ion implantation technique can be effectively solved. In addition, the high dose rate and simplicity of the equipment enable the ion implantation a commercially affordable process. In this work, plasma source ion implantation technique was used to improve the wear resistance of Co-cemented WC. which has been extensively used for high speed tools. Nitrogen and carbon ions were implanted using the pulse bias of -602kV, 25 sec and at various implantation conditions. The implanted samples were examined using scanning Auger electron spectroscopy and XPS to investigate the depth distributions of implanted ions and to reveal the chemical state change due to the ion implantation. The implanted ions were found to have penetrated to the depth of 3000$\AA$. The wear resistance of the implanted samples was measured using pin-on-disc wear tester and the wear tracks were examined with alpha-step profilometer.