• 소음진동
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• 제6권6호
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• pp.843-849
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• 1996

Locations and emission characteristics of noise source of motor vehicles are great important factors to control the road traffic noise in effective ways. From results of this study on emission characteristics of engine and exhaust noise, we could find that every noise emission of different kind of vehicles has smilar pattern. The main emission locations of engine noise for the front of vehicle became the space between the road surface and bottom of the body and radiator grill, and for the side of vehicle became the space between the road surface and bottom nearby the front wheel. In case of exhaust noise of passenger-car and light truck, all the highest sound intensity level located near surface of road. But it is hard to conclude the height of noise source of driving vehicles with only results of this study. So further studies are needed to check the emission characteristics of noise.

• 한국분무공학회지
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• 제18권1호
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• pp.16-20
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• 2013

The investigation was conducted to analyze the exhaust emission characteristics in diesel engine according to intake air mass flow. In this study, the test diesel engine with a 5,899 cubic centimeter displacement and power of the 260 ps was used to analyze the emission characteristics according to the intake air mass flow. In addition, the test modes were applied by the ND-13 and ETC mode. In order to analyze the emission characteristics, the engine dynamometer with 440 kW and emission gas analyzer (AMA-4000) were utilized. From the experimental results, it is revealed that the NOx and HC emissions in the intake air mass flow of large amount have high levels compared to those in the intake air mass flow of small amount in the ND-13 mode. However, the PM emission was shown the opposite trend in the NOx and HC emission due to the trade-off relation between the NOx and PM.

• 한국표면공학회지
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• 제37권6호
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• pp.313-318
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• 2004

Vertically-aligned and uniformly-distributed CuO nanowires were formed on copper-coated Si substrates by wet chemical process, immersing them in a hot alkaline solution. The effects of hydrogen plasma treatment on the field emission characteristics of CuO nanowires were investigated. It was found that hydrogen plasma treatment enhanced the field emission properties of CuO nanowires by showing a decrease in turn-on voltage, and an increase in emission current density, and stability of current-voltage curves. However, the excessive hydrogen plasma treatment made the I-V curves unstable. It was confirmed by XPS (X-ray Photoelectron Spectroscopy) analysis that hydrogen plasma treatment deoxidized CuO nanowires, thereby the work function of the nanowires decreased from 4.35 eV (CuO) to 4.1 eV (Cu). It is thought that the decrease in the work function enhanced the field emission characteristics. It is well-known that the lower the work function, the better the field emission characteristics. The results suggest that the hydrogen plasma treatment is very effective in achieving enhanced field emission properties of the CuO nanowires, and there may exist an optimal hydrogen plasma treatment condition.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.149-149
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• 2010

The effect of titanium (Ti) coating over the surface of carbon nanotubes (CNTs) on field emission characteristics was investigated. Since the work function of CNTs emitter is about 5.0 eV, field emission would be observed at lower voltage if this work function gets lower. Work function of Ti is approximately 4.09eV. Field emission characteristics of as-grown and Ti-coated CNTs were measured in a diode-type configuration. The resultant emission characteristics revealed that thin($50{\AA}$-thick) Ti-coated CNTs could be a better electron emitter with lower emission voltage and higher emission efficiency.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2000년도 춘계학술대회 논문집(Proceeding of the KOSME 2000 Spring Annual Meeting)
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• pp.52-59
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• 2000

Experimental studies were performed to improve the THC emission characteristics by optimizing the flow in the exhaust manifold and CCC in a SI engine. For this purpose the flow characteristics in the exhaust manifold and CCC were measured by using LDV technique under various engine conditions, Referring to these data a new type exhaust manifold was designed to improve the cold-start emission characteristics and the response characteristics of {{{{ OMICRON _2}}}} sensor by optimizing the flow pattern and reducing the thermal inertia of the exhaust manifold system. It was found through the vehicle emission tests that the emission characteristics of THC of the new type exhaust manifold was improved by 12% through the optimizing the flow pattern in the exhaust manifold.

• 한국분무공학회지
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• 제2권2호
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• pp.43-50
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• 1997

The purpose of this investigation is to carry out, the influence factor on the fuel spray characteristics for improve the engine combustion performance and exhaust omission in direct injection type diesel engine. The fuel properties, fuel spray structure and the shape or the piston surface of diesel engine play an important role of engine combustion process and exhaust emission. In order to obtain the effect of using auxiliary chamber and emulsified fuel on the fuel spray characteristics the experiment un conduct with single cylinder direct injection type diesel engine to examine the engine performance and gas emission. The results of this investigation showed that the increase auxiliary chamber volume and emulsified fuel give an effect on the fuel spray characteristics by reduced the concentration of nitric oxide emission in the combustion chamber. Also it can improve the combustion characteristics such as cylinder pressure, rate of pressure rise and rate of heat release.

• 한국표면공학회지
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• 제29권5호
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• pp.505-511
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• 1996

The field emission characteristics of diamond films deposited by microwave plasma enhanced chemical vapor deposition (MPECVD) method were investigated. Diamond films were deposited on n-type Si(100) wafer using various mixtures of hydrogen and methane gas, and the I-V characteristics are measured. We observed that the field emission characteristics depend on the $CH_4$ concentration and the diamond film thickness. All the films show remarkable emission characteristics; low turn-on voltage, high emission current density at lower voltage, uniform stable current density, and good stability and reproducibility. The threshold field for producing a current density of 1mA/$\textrm{cm}^2$ is found as low as 7.6V/$\mu\textrm{m}$.

• Advances in Computational Design
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• 제4권4호
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• pp.367-379
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• 2019

Multiple Inputs and Multiple Outputs (MIMO) Fuzzy logic model is developed to predict the engine performance and emission characteristics of pongamia pinnata biodiesel with hydrogen injection. Engine performance and emission characteristics such as brake thermal efficiency (BTE), brake specific energy consumption (BSEC), hydrocarbon (HC), carbon monoxide (CO), carbon dioxide ($CO_2$) and nitrous oxides ($NO_X$) were considered. Experimental investigations were carried out by using four stroke single cylinder constant speed compression ignition engine with the rated power of 5.2 kW at variable load conditions. The performance and emission characteristics are measured using an Exhaust gas analyzer, smoke meter, piezoelectric pressure transducer and crank angle encoder for different fuel blends (Diesel, B10, B20 and B30) and engine load conditions. Fuzzy logic model uses triangular and trapezoidal membership function because of its higher predictive accuracy to predict the engine performance and emission characteristics. Computational results clearly demonstrate that, the proposed fuzzy model has produced fewer deviations and has exhibited higher predictive accuracy with acceptable determination correlation coefficients of 0.99136 to 1 with experimental values. The developed fuzzy logic model has produced good correlation between the fuzzy predicted and experimental values. So it is found to be useful for predicting the engine performance and emission characteristics with limited number of available data.

• 한국표면공학회지
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• 제48권4호
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• pp.174-178
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• 2015

We studied emission characteristics for blue fluorescent dual-side emission OLED with Al cathode thickness variation. In the bottom emission OLED of Al cathode with 10, 15, 20, 25, 30, and 150 nm thickness, maximum luminance showed 36.1, 8,130, 9,300, 12,000, 13,000, and $12,890cd/m^2$, and maximum current efficiency showed 2, 8.8, 10, 10.5, 10.8, and 11.4 cd/A, respectively. The emission characteristics of the bottom emission seemed to be improved according to decrease of resistance as the thickness of Al cathode increase. In the top emission OLED of Al cathode with 10, 15, 20, 25, and 30 nm thickness, maximum luminance showed 4.3, 351, 131, 88.6, and $33.2cd/m^2$, and maximum current efficiency showed 0.23, 0.38, 0.21, 0.16, and 0.09 cd/A, respectively. It yielded the highest maximum luminance and maximum current efficiency in Al cathode thickness 15 nm. It showed a tendency to decrease as the thickness of Al cathode increase. The reason for this is due to decrease of transmittance with increasing of Al cathode thickness. The electroluminescent spectra of bottom and top emission OLED were not change.

• 동력기계공학회지
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• 제6권3호
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• pp.17-23
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• 2002

The purpose of this study is to investigate the combustion emission characteristics changing auxiliary air injection in combustion field of coaxial swirling diffusion combustor. For this purpose, mean temperature, CO, CO2, O2 and HC concentration were measured by changing excess air ratio and auxiliary air injection. As a result of this study, mean temperature, CO2 emission were increased and CO emission decreased by increasing auxiliary air. Therefore, this paper showed the auxiliary air injection effected strongly on flame structure and combustion emission characteristics.