• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.12
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• pp.591-596
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• 2006

we have been developed on the ultra high concentration ozone generator system which is the core technology in the realization of the semiconductor photoresist strip process using the ozone-vapor chemistry. The proposed ozone generator system has the structure of the surface discharge type which adopt the high purity ceramic dielectric tube. We investigate the performance of the proposed ozone generator system experimentally and the results show that the system has very high ozone concentration characteristics of $19.7[wt%/O_2]$ at the flow rate of $0.3[{\ell}/min]$ of each discharge cell. As a result of the silicon wafer photoresist strip test, we obtained the strip rate of about 400[nm/min] at the ozone concentration of $16[wt%/O_2]$ and flow rate of $8[{\ell}/min]$. So, we confirmed that it's possible to use the proposed high concentration ozone generator system for the ozone-vapor photoresist strip process in the semiconductor and FPD industry.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.10
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• pp.1989-1994
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• 2009

This study purposes are improvement of system (lamp & ballast) efficacy with and optical characteristics through the developed ceramic arc tube. The designed electronic ballast is substituted for conventional magnetic ballast. These electric signal and optical, thermal characteristics through the improving efficacy of lighting system compared with conventional magnetic ballast. properties of lamp by driving method is researching in ballast. Particularly, electronic ballasts, which improved against weakness of Magnetic Ballast, are researching and applying to control of ceramic metal-halide lamp. but One major limitation is the acoustic resonance problem in CMH lamps at high-frequency operation. In order to avoid acoustic resonance, driving frequency decided 21[kHz]. Before discharge in this paper. The PSpice simulation result obtained sufficient voltage gain and the ignition voltage obtained over 3[kV] at 75[kHz]. After discharge, driving voltage obtained approximately 90[Vrms] at 21[kHz].

• Proceedings of the KIEE Conference
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• summer
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• pp.1193-1195
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• 2004

Ozone gas is one of the strongest oxidizing and bleaching agents which leave no residues harmful to the global environment. In recent years, the ozone generator has been widely utilized, However, it has been known that a broader application of ozone is hindered primarily because of its low efficiency of generation. Thus, it is more indispensable to improve actual system efficiency of the silent discharge type ozonizer using high frequency inverter. This paper presents a multi level resonant ozone power regulation by association of high frequency transformers and full bridge invert. And proposed resonant inverter system can generate continuous output voltage. can control linearly quantity of ozone gas. This invert that add PWM forms within square forms of output voltage about one level range. The power regulation characteristics and operating performances of silent discharge (SD)type ozone generating tube load driven by this load proposed inverter using FET modules are illustrated from a practical point of view, which can operate under stable conditions of basic level and PWM hybrid control strategy implemented DSP(2406). The effectoveness of propsed invert type ozonizer is proved by experiment results.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.12
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• pp.622-626
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• 2001

HID(high intensity discharge)lamps are high pressure mercury lamp, high pressure sodium lamp and metalhalide lamp. metalhalide lamp among these lamps has considered to be one of the most effective artificial light sources and this lamp has good efficiency, good color rendition and good focusing capability, But the shortcorning of metalhalide lamp is known as acoustic resonance phenomena in the discharge tube when lighted by electronic ballast and then acoustic resonance cause various problems such as the arc instability, light output fluctuations. In this paper, to reduce the acoustic resonence phenomena, the electronic ballast was designed by three methods for high frequency operation wish frequency-modulated sinusodial waves in acoustic resonance frequency band. These frequency-modulated methods are resonance frequency and resonance frequency, resonance frequency and non-resonance frequency non-resonance frequency and non-resonance frequency Experiment results could't show the Presence of acoustic resonance visually and it proved that the resonance-generating conditions can be avoided by continuously changing the two operating frequencies in acoustic resonance band (20.59kHz∼94.2kHz).

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.05a
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• pp.309-312
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• 2009

본 논문에서는 탈색, 탈취 및 상 하수 정수처리에 많이 이용되고 있는 오존의 효과적인 발생을 위하여 세라믹을 이용하여 유전체 장벽 방전에 의한 오존생성특성을 연구하였다. 세라믹과 전극으로 구성된 전극 수와 오존생성을 위한 반응가스인 Air와 Oxygen의 투입량 변화에 따른 오존생성농도, 오존발생량 및 오존생성수율 특성을 분석하였다. 그 결과, 세라믹과 전극으로 구성된 전극 수가 많을수록 오존생성특성은 증가하였고, 원료가스를 Air와 Oxygen으로 사용한 경우 Oxygen을 원료가스로 사용했을 때 전극 수 5 및 10개에서 모두 오존생성특성이 우수하게 나타났으며, 그 결과 전극 수가 5개인 경우, 오존생성농도는 약 4.2배, 오존발생량은 2.5배, 오존생성수율은 2.5배 증가하였으며, 전극 수가 10개인 경우, 오존생성농도는 약 5.1배, 오존발생량은 3.8배, 오존생성수율은 3.4배 증가하였다.

• Applied Chemistry for Engineering
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• v.24 no.5
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• pp.544-550
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• 2013

This work investigated the environmental application of an underwater dielectric barrier discharge plasma reactor consisting of a porous hydrophobic ceramic tube to the decolorization of an azo dyeing wastewater. The reactive species generated by the plasma are mostly short-lived, which also need to be transferred to the wastewater right after the formation. Moreover, the gas-liquid interfacial area should be as large as possible to increase the decolorization rate. The arrangement of the present wastewater treatment system capable of immediately dispersing the plasmatic gas as tiny bubbles makes it possible to effectively decolorize the dyeing wastewater alongside consuming less amount of electrical energy. The effect of discharge power, gas flow rate, dissolved anion and initial dye concentration on the decolorization was examined with dry air for the creation of plasma and amaranth as an azo dye. At a gas flow rate of $1.5Lmin^{-1}$, the good contact between the plasmatic gas and the wastewater was achieved, resulting in rapid decolorization. For an initial dye concentration of $40.2{\mu}molL^{-1}$ (volume : 0.8 L; discharge power : 3.37 W), it took about 25 min to attain a decolorization efficiency of above 99%. Besides, the decolorization rate increased with decreasing the initial dye concentration or increasing the discharge power. The presence of chlorine anion appeared to slightly enhance the decolorization rate, whereas the effect of dissolved nitrate anion was negligible.

• Analytical Science and Technology
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• v.15 no.6
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• pp.514-520
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• 2002

The electrothermal vaporization (ETV) hollow cathode glow discharge atomic emission spectrometer for analysis of liquid sample has been developed and characterized. This system has improved the sample introduction method of electrothermal vaporization and the hollow cathode glow discharge. The sample introduction method was possible to provide high analyte transport efficiency to the plasma by helix coil made of tungsten material. In addition, small volume samples (<$30{\mu}{\ell}$) could be used. The system has glow discharge cell with special design for improvement of precision. The effect of discharge parameters such as discharge power, gas flow rate has been studied to find optimum condition. The emitted light was effectively carried into detector by fiber optic cable in UV region. The calibration curve of Pb, Cd were obtained with 3 samples.

• Journal of the Korean Society for Nondestructive Testing
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• v.20 no.1
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• pp.1-9
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• 2000

This study shows the defect detection and sizing capability of ultrasonic guided waves in the nondestructive inspection of heat exchanger and steam generator tubing. Phase and group velocity dispersion curves for the longitudinal and flexural modes of a sample Inconel tube were presented for the theoretical analysis. EDM(Electric Discharge Machining) wears in tubing under a tube support plate and circumferential laser notches in tubing were detected by an axisymmetric and a non-axisymmetric transducer set up, respectively. EDM wears were detected with L(0, 2), L(0, 3) and L(0, 4) modes and among them L(0, 4) mode was found to be the most sensitive. It was also found that the flexural modes around L(0, 1) mode could be used for the detection and sizing of laser notches in the tubing.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.1158-1161
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• 2004

This paper presents structural characteristics of station class lightning arresters and electrical characteristics of manufactured ZnO varistor blocks which are usable in those arresters. Three types of station class lightning arresters were investigated and those are a ceramic arrester, a FRP tube type polymer arrester, and a FRP rod type polymer arrester. Each arrester has merits and demerits with structural characteristics. In general, polymer arresters were made of silicon rubber for housing materials, FRP tube or rod for mechanical strength, ZnO blocks for electrical characteristics, and metal parts for electrical contact and the silicon rubber, the housing materials, was directly injected to the arrester module which was assembly composed of electrodes, ZnO blocks and FRP tube or rod, and to prevent the nonlinear electric fields distribution on upper parts of arresters, the grade ring was adopted to the upper electrodes. The reference voltage, nonlinear coefficient, residual voltage, and voltage ratio of manufactured ZnO varistors are 4.90kV, 50, 9.54kV, 1.94, respectively. Compared to designed electrical characteristics, the reference voltage was low for 600v and the voltage ratio was slightly high. However, the characteristics of discharge withstand was so excellent that the mechanical destruction does not occur at the impulse current of $8/20{\mu}s$ 10kA for 100 times.

• Annals of Coloproctology
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• v.34 no.6
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• pp.317-321
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• 2018

Purpose: We evaluate the role of transanal tube drainage (TD) as a conservative treatment for patients with anastomotic leakage (AL). Methods: Patients treated for AL who had undergone a low or an ultralow anterior resection with colorectal or coloanal anastomosis for the treatment of rectal cancer between January 2013 and January 2017 were enrolled in this study. The data were collected prospectively and analyzed retrospectively. The primary outcomes were the diagnosis and the management of AL. Results: Two hundred thirteen consecutive patients, 122 males and 91 females, were included. The mean age was $66.91{\pm}11.15years$, and the median body mass index was $24kg/m^2$ (range, $20-35kg/m^2$). The median tumor distance from the anal verge was 8 cm (range, 4-12 cm). Ninety-three patients (44%) received neoadjuvant therapy for nodal disease and/or locally advanced rectal cancer. Only 13 patients (6%) developed AL. Six patients developed subclinical AL as they had a defunctioning ileostomy at the time of the initial procedure. They were treated conservatively with TD under endoscopic guidance in the endoscopy unit and received intravenous antibiotics. Six weeks after discharge, these 6 patients underwent follow-up flexible sigmoidoscopy which showed a completely healed anastomotic defect with no residual stenosis. Seven patients developed a clinically significant AL and required reoperation with pelvic abscess drainage and Hartmann colostomy formation. Conclusion: These results suggest that TD for management of patients with AL is safe, cheap, and effective. Salvaging the anastomosis will help decrease the need for Hartmann colostomy formation. Proper patient selection is important.