• Analytical Science and Technology
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• v.18 no.2
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• pp.112-119
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• 2005

This study reports on the efficiency of cleaning enameled magnet wire using a sulfuric acid $H_2SO_4$ and removal of dissolved organic material using hydrogen peroxide $H_2O_2$ and nitric acid $HNO_3$ at $80^{\circ}C$. The method involves the addition of pure $H_2SO_4$ and $H_2O_2$ or $HNO_3$. Layers of enameled organic material were dissolved by 90% $H_2SO_4$ and the solution was maintained as 35% $H_2O_2$ or 60% $HNO_3$. $H_2O_2$ content in aqueous $H_2O_2$ was maintained as 8.8 : 1.0. An initial concentration of $H_2SO_4$ in dissolution conditions was accomplished within 15 min, with a stripping time of about 2 h. The concentrations of $H_2O_2$ and $HNO_3$ in the processing bath were relatively low, but sufficient enough to produce an effective amount of power in the bath for the removal of the enamel material. The cleaning effect of enameled organic material involves the dehydration by $H_2SO_4$ and the oxidation by $H_2O_2$ or $HNO_3$.

• Journal of the Korean Society of Safety
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• v.21 no.4 s.76
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• pp.60-65
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• 2006

It is a well known fact that LCD is a central part of the IT industry which is important in the present and the future. But the biggest problem of LCD manufacturing is maintaining a cleaning room environment and administration. Therefore the purpose of this study is to first, prevent the yield depreciation and damage of products, and second, protect the worker ftom accidental electrostatic discharge during LCD manufacture. The soft x-ray ionizer is a type of electrostatic reducer device. It protects against electrostatic discharge in the cleaning room environment and is a necessary environmental factor during LCD production. The positive aspects of the soft x-ray are its shorter time and wider angle of exposure. But the negative aspect of the soft x-ray is its need for several shielding of protection from the harmful x-ray exposure. On this study, the development of the Air Nozzle-type ionizer to amend and refine some problems. For example, examined the electrostatic reduce device of a soft x-ray type and discovered the ion did not go inside well. also workers to be free from danger. An Air Nozzle-type ionizer is comprised of soft x-ray radiation and ionized air production. Air is injected through the nozzle after being ionized from radiation. It supplies air keeping the same pressure into the end foundation of ion production. The soft x-ray is the structure which radiates ionized air through the nozzle (21 holes) having micro holes of the ionizable radiation after ionizing the inside air by the ion production. A worker does not need a cover to protect against x-rays and the Air Nozzle-type ionizer is easy to set up and is more effective at eliminating electrostatic.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.15 no.1
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• pp.62-70
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• 2019

The APR1400 reactor may be operated for a long time under high temperature and pressure conditions, causing damage to the stud holes and causing stud bolts and holes to stick. The present practice is to manually remove the anti-sticking agent and foreign matter remaining in the APR1400 reactor stud hole and to visually check the surface condition of the thread to check the damage status of the threads. In the case of the APR1400 reactor stud holes, manually cleaning the threads increases the risk of radiation exposure and operator's fatigue. To avoid this, the autonomous mobile robot is used to automatically clean the reactor stud holes. The purpose of this study is to optimize the cleaning performance of the mobile robot by looking at the behavior of the surface roughness of the stud surface cleaned by the brush attached to the mobile robot due to changes in brush material, thickness of wire, and rotation speed. A microscopic approach to the surface roughness of the flank is needed to investigate the effects of the newly proposed brush of the autonomous mobile robot on the thread holes. According to this experiment, it is reasonable to use STS brush rather than Carbon one. Optimal operating conditions are derived and the safety of APR1400 reactor stud holes maintenance can be improved.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2002.11a
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• pp.207-211
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• 2002

Anodizing film was prepared by anodic oxidation of pure aluminum(purity > 99.50) using DC power supply for constant current mode in an electrolytic solution of surface of sulfuric acid. Effects of pre-treatment process such as chemical polishing, acid cleaning, alkali etching before anodic oxidation, were studied to microstructures and surface morphologies. A roughness on surface of anodizing film had to be decreased for amorphous phase by anodic oxidation. A roughness on surface of anodizing film decrease as annealing temperature increased in chemical polishing.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1823_1824
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• 2009

원자력 발전소 운전과정에서 발생하는 각종 폐액은 저장/여과 과정을 거치게 된다. 이러한 폐액의 저장/여과 과정에서 탱크 내에 침적된 방사성 슬러지들은 농축 고화 처리가 요구 되며 방사선량에 따라 작업자의 접근이 제한적이다. 본 논문에서는 탱크나 섬프(Sump)내의 방사성 슬러지를 제거하기 위하여 개발 중인 로봇의 기능과 이를 이용한 슬러지 제거 기초실험 결과를 제시한다.

• Proceedings of the KAIS Fall Conference
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• 2011.12b
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• pp.391-393
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• 2011

본 연구에서는 원자력 발전 및 화력 발전소에서 Turbine 운전 시 열교환기 및 콘덴서에 증기를 응축시 열효율을 높여주기 위해 콘덴서 Tube 내에 이물질 및 스케일을 Sponge Ball을 이용하여 자동으로 제거하는 장치로서 콘덴서 튜브 클리닝 시스템(CTCS)에 사용되고 있는 Screen 재료인 Duplex Stainless Steel UNS S31803의 파손사례에 대해 연구하였다. 파손원인 분석은 스크린의 강도해석, 재료의 화학분석시험, 조직시험 및 점용접부의 신뢰성 시험(Peel-off test)으로 수행되었고 저항용접부의 용접 불량 때문에 발생하였을 확인하였다.

• Journal of information and communication convergence engineering
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• v.6 no.3
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• pp.305-309
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• 2008

This paper presents an innovative prototype of a new conceptual electromagnetic induction eddy current based fluid heating appliance using voltage-fed quasi resonant zero voltage soft switching PWM high-frequency inverter using IGBTs, which can operate at a constant frequency variable power regulation scheme. The promising simple high efficient low noise inverter type electromagnetic induction eddy current based pipeline fluid heating appliance is proposed for saturated steam generator, superheated steam generator, hot water and hot air producer, metal catalyst heating for exhaust gas cleaning in engine. Under these technological backgrounds, a novel electromagnetic induction eddy current Dual Packs Heater(DPH) based pipeline fluid heating incorporates thin metal layer type package for continuous fluid heating appliances applying two types of voltage-fed quasi load resonant ZVS-PWM high frequency inverter. The unique features of a novel electromagnetic induction eddy current DPH based continuous pipeline fluid heating appliance is illustrated on the basis of simulation and discussed for the steady state operating characteristics and experimental results.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.1
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• pp.84-94
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• 2007

As a reactor coolant pump(RCP) is operated in the nuclear power system for a long time. so its surface is continuously contaminated by radioactive scales. In order to perform regular or emergency repair about RCP internals a special decontamination process should be used to reduce the radiation from the RCP surface by means of chemical cleaning. In this study, applicable possibility in chemical decontamination for RCP was investigated on the various materials. The STS 304 showed the best electrochemical properties for corrosion resistance than other materials. However, the pitting corrosion was slightly generated in both STS 415 and STS 431 with the increasing numbers of cycle and intergranular corrosion were sporadically observed. The size of their pitting corrosion and intergranular corrosion were also increased with increasing cycle numbers.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.921-926
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• 1997

SOI(Silicon On lnsulator) technology is many advantages in the gabrication of MOS(Metal-Oxide Semiconductor) and CMOS(Complementary MOS) structures. These include high speed, lower dynamic power consumption,greater packing density, increased radiation tolearence et al. In smiple form of bonded SOL wafer manufacturing, creation of a bonded SOI structure involves oxidizing at least one of the mirror polished silicon surfaces, cleaning the oxidized surface and the surface of the layer to which it will be bonded,bringing the two cleanded surfaces together in close physical proximity, allowing the subsequent room temperature bonding to proceed to completion, and than following this room temperature joining with some form of heat treatment step,and device wafer is thinned to the target thickness. This paper has been performed to investigate the possibility of the bonded SOI wafer manufacturing Especially, we focused on the bonding quality and thinning method. Finally,we achieved the bonded SOI wafer that Si layer thickness is below 3 .mu. m and average roughness is below 5.angs.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.864-874
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• 2007

Suspension insulator in Catenary Trolley Wire Systems must have two characteristics, electric insulation and mechanical endurance. Because suspension insulator is used in supporting and insulating position between power supply parts and earth conducted supporting parts. The insulator's electric characteristics can be influenced by surface pollution and damage from the environment such as humidity, dust, smoke, salt. etc. And, the insulating parts can be electrically short. These electrically damaged insulator can cause serious accidents that have far-reaching effect. So appropriate management basis of suspension insulator is needed. And we present appropriate cleaning and the changing period of suspension insulator on the basis of actual data.