• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.921-924
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• 2004

This paper is to investigate a crack for plasma sprayed MCrAlY coated material by acoustic emission method in 4-point bending test. The CoNiCrAlY is coated on Inconel-718 by vacuum plasma spray process. Micro-hardness measurement was conducted by means of Micro Vickers-hardness indentor. The porosity of coating layer was measured using a SEM and Image Analyzer. AE monitoring system is composed of PICO type sensor, a wide band preamplifier(40dB), a PC and AE DSP(16/32 PAC) board. The AE count, Hit and energy of coating specimens is measured according to coating thickness.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1574_1575
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• 2009

This paper investigates the reduction of RE(Radiated Emission) noise in a high power LED module circuit using PWM(Pulse Width Module) switching controller circuit. Poorly designed LED lighting module can experience the RE and CE(Conducted Emission) noise problem. This paper propose the reduction of noise source and improvement of EMI filter design in a high power LED lighting module. The experimental and simulation results showed that reduce the RE noise level effectively.

• 대한산업공학회지
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• 제43권3호
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• pp.203-212
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• 2017

Emissions Trading System (ETS) is utilized in many countries, including South Korea, as an efficient policy to abate GHG (Greenhouse Gas) emissions. Grandfathering on the basis of historic emissions is used as the way to allocate permits in South Korea. It, however, has caused an increase in the emission permits and lack of equity. To overcome these drawbacks, we propose an alternative DEA model for centralized allocation of emission abatement to evaluate the amount of emissions abatement by company based on the energy efficiency. In addition, an empirical analysis of 36 assigned companies for ETS in Korean metal industry is conducted to validate the feasibility of the proposed model. The result of the analysis shows that energy-efficient companies achieve reduced target of the emissions abatement and companies with low energy efficiency score are turned out to have contrary outcome, against the result of applying Grandfathering.

• 한국대기환경학회지
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• 제10권3호
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• pp.197-202
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• 1994

The research described in this paper is conducted to estimate the short-term concentrations of nonreactive pollutants such as CO and TSP from vehicle emissions near Kyungbu Highway. An emphasis is placed on the development of a model for a hourly traffic volume for each vehicle type, which is based on real traffic data. By using the model and the calculated emission factor due to vehicle speed for each vehicle type, the emission rate of CO and TSP for each traffic line is computed. The hourly emission rate and meteorological data are used to simulate by HIWAY-2 for the distance of 5m and 10m from the downwind edge of Kyungbu Highway located in relatively uncomplicated terrain.

• 한국연소학회지
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• 제8권2호
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• pp.1-6
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• 2003

Numerical simulations are conducted at atmospheric pressure in order to understand the effect of the oxygen enrichment level on structure of $CH_4/O_2/N_2$ premixed flames. Under several equivalence ratios the flame speeds are calculated and compared with those obtained from the experiments, the results of which are in good agreement. The effects of the oxygen enrichment are investigated on flames under fuel-rich conditions. As the oxygen enrichment level is increased from 0.21 to 1, the flame speed and the temperature are increased. The emission index of $CO_2$ is decreased in cases of flames for fuel rich mixtures, so the efficiency of combustion may be decreased. The maximum emission index of NO is obtained for 0.6 of the oxygen enrichment level.

• 한국항공우주학회지
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• 제42권10호
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• pp.878-883
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• 2014

본 논문에서는 2014년 6월 20일에 발사된 스페인의 저궤도 위성인 Deimos-2 발사모델의 시스템 레벨 전자기파(EMC) 테스트 결과를 나타내었다. Deimos-2 위성은 구조적인 측면과 더불어 단위 모듈 레벨에서부터 EMC를 고려한 설계가 이루어졌다. Auto-Compatibility, Radiated Emission, Radiated Susceptibility 테스트를 수행하였고, 측정 결과는 Deimos-2 프로그램의 시스템 EMC 기준을 만족하였다.

• 대한기계학회논문집B
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• 제29권6호
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• pp.730-736
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• 2005

It has been reported that the interacting multiple jet flames of propane fuel are not extinguished even at the choking velocity at the nozzle exit if eight small nozzles are arranged along the imaginary circle of $40{\sim}72$ times the diameter of single nozzle. In this research, experiments were conducted to know the NO and CO emission characteristics of the interacting flames. Measurements along the centerline of the flame revealed that decrease in CO concentration was followed by the NO decrease and $O_2$ increase. It was found that interacting flame emitted less NO than that of similar area single jet flame. Also, NO emission of partially premixed interacting flame was decreased up to $17\%$ of that of non-premixed multiple jet flame. Though the mechanism of the NO reduction was not clear from this experiment, it's been shown that partially premixed multiple jet flames could be used to achieve clean and highly stable combustion.

• Journal of Advanced Marine Engineering and Technology
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• 제16권4호
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• pp.60-77
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• 1992

The effects of exhaust gas recirculation(EGR) on the characteristics of exhaust emissions and specific fuel consumption have been investigated using an eight-cylinder, four cycle, direct injection diesel engine operating at several loads and speeds. The experiments in this study are conducted on the fixed fuel injection timing of $38^{\circ}$ BTDC regardless of experimental conditions. In conclusion, it is found that $NO_{x}$ emission is markedly reduced with the drop of burnt gas temperature at high speeds and loads especially as the EGR rate increases, while the soot particulate rises with EGR rate and load at a given engine speed, especially high loads. The reduction of exhaust emissions within the Korea heavy duty diesel engine emission standards can be roughly achieved by the optimal EGR rate without degarding the specific fuel consumption, based on the correlations between exhaust emissions.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1995년도 Proceedings of the Korea Automation Control Conference, 10th (KACC); Seoul, Korea; 23-25 Oct. 1995
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• pp.142-145
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• 1995

It is important from prevention of the malfunction and an important accident by the failuer, to detect a failuer in revolution devices. The acoustic emission(AE) method is expected as means that defects an abnormal phenomenon of revolution devices earlily and utilized. Although a research example by the AE method is reported regarding a gears, little reserch has been conducted using the AE method for running gears in a bending fatigue process of spur gear teeth. Therefore, in this report, with two micro AE sensors attached to the side of the gear, AE was measured in a bending fatigue process of a carburizing gear by using the power circurating-type machine and AE source location in gear teeth were required. By various analysis in these data, the AE characteristics in the fatigue damaging process of the gear tooth were determined.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1993년도 제18회 학술대회 초록집
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• pp.77-84
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• 1993

Systems with journal bearings generally operate in large scale and under severe loading conditions such as steam generator turbines and internal combustion engines, in contrast to the machineries using rolling element bearings. Failure of the bearings in these machineries can result in the system breakdown. To avoid the time consuming repair and considerable economic loss, the detection of incipient failure in journal bearings becomes very important. In this experimental approach, acoustic emission monitoring is employed to the detection of incipient failure caused by intervention of foreign particles most probable in the journal bearing systems. It has been known that the intervention of foreign materials, insufficient lubrication and misassembly etc. are principal factors to cause bearing failure and distress. The experiment was conducted under such designed conditions as inserting alumina particles to the lubrication layer in the simulated journal bearing system. The results showed that acoustic emission could be an effective tool to detect the incipient failure in journal bearings.