• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.2
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• pp.20-27
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• 2007

[ $SF_6$ ] gas for compacted power facilities has a important role as an insulation gas. It is very blown well that $SF_6$ gas has the superior characteristics as an insulation gas. For reliable operation of SF6-gas-based high and medium voltage equipment it is very important to keep the insulation ability within a safe range. And the experimental and measuring system were implemented. The test chamber designed to endure up to 3 atmospheric pressure. The analysis results of the experimental data shows that positive partial discharge can be detected by discharge current and UHF signal. Additionally it is shown the possibility that $CO_2$ gas sensor of semiconductor type can be detect the variation of $SF_6$ gas condition. The UHF sensor shows good feature to detect the variation of $SF_6$ gas condition for partial discharge and breakdown discharge.

• Journal of the Korean Vacuum Society
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• v.22 no.5
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• pp.238-244
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• 2013

Doping process using laser is an important process in fabrication of solar cell for heat treatment. However, the process of using the furnace is difficult to form a selective emitter doping region. The case of using a selective emitter laser doping is required an expensive laser equipment and induce the wafer's structure damage due to high temperature. This study, we fabricated a new costly plasma source. Through this, we research the selective emitter doping. We fabricated that the atmospheric pressure plasma jet injected Ar gas is inputted a low frequency (a few tens kHz). We used shallow doping wafers existing PSG (Phosphorus Silicate Glass) on the shallow doping CZ P-type wafer. Atmospheric plasma treatment time was 15 s and 30 s, and current for making the plasma is 40 mA and 70 mA. We investigated a doping profile by using SIMS (Secondary Ion Mass Spectroscopy) and we grasp the sheet resistance of electrical character by using doping profile. As result of experiment, prolonged doping process time and highly plasma current occur a deeper doping depth, moreover improve sheet resistance. We grasped the wafer's surface damage after atmospheric pressure plasma doping by using SEM (Scanning Electron Microscopy). We check that wafer's surface is not changed after plasma doping and atmospheric pressure doping width is broaden by increase of plasma treatment time and current.

• Korean Chemical Engineering Research
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• v.48 no.1
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• pp.116-120
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• 2010

$CO_2$ is regarded as one of the greenhouse gases(GHG), which is the main reason of climate change. In order to achieve lower $CO_2$ emissions, several efforts have been conducted worldwide. $CO_2$ capture & storage(CCS) technology development is needed for a coal-fired combustion power plant because of huge $CO_2$emission. Oxy fuel combustion, one of the CCS technologies has been considered as a primary concern, nowadays. Oxy-fuel combustion needs flue gas recirculation(FGR) for stable operation and enrichment of $CO_2$ concentration in the flue gas. FGR adoption for oxy-fuel combustion requires development of effective desulfurization and dust removal technology. In this study, desulfurization characteristics of lime and dust removal technology have been researched in the laboratory scale coal combustor.

• Journal of Environmental Science International
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• v.26 no.2
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• pp.231-238
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• 2017

Rapid industrial development has led to a serious problem of pollution in the industrial sector. With the increasing social need for environmental protection, research on air pollution prevention equipment for reducing pollutants in industrial processes is actively being undertaken. The deterioration of existent, installed facilities, their increased emission rates, and the strengthening of the effluent quality standards make complying with permissible emission standards difficult. In fact, installing new electric precipitators or complementing existent facilities is inevitable. The expansion and complementation of the installed electrical precipitators have led to improvements in dust collection efficiency, shorter working times, and lower costs. Because of its easy installation and simple manufacturing process, the production method with the discharge electrode of an electric precipitator is widely used. The following conclusions were reached by classifying discharge electrodes into four types based on the production method and mutually comparing them by their dust collection efficiency. None of the four types used in this study were damaged by impact. However, we were able to confirm some strain from the compression sites of both type A and type B. Both type B and type C are expected to have greater dust collection efficiencies than the other models due to their large vibration transmissibility. Moreover, the high vibrational energy is expected to cause rapping damage during its operation. Particularly, in the case of type B, some of the strain was found at the end of the compression site. The coupling schemes of both type C and type D are out of vibration transmissibility. On the other hand, the ability to maintain straightness and solidity of the side is regarded as outstanding and stable. Type D has outstanding on-site workability, considering the presence of locking, structural stability, and work conditions. From these experiments, we determined that type C is the most ideal connection method of discharge electrode, considering its construction period of renovation. Type C is inferior to type D with regard to on-site workability. However, type C has outstanding dedusting transmission with regard to the straightness, solidity maintenance, and vibration of shearing stress.