• 한국가시화정보학회:학술대회논문집
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• 2001.12a
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• pp.36-43
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• 2001

The flow field structures of two interacting parallel supersonic free jets are studied by flow visualization using planar laser-induced fluorescence of NO seeded in nitrogen gas. The experiments are carried out for several distances between two orifice centers and for various ratios of the pressure in the reservoir to that in the expansion chamber. The flow fields are visualized mainly on the plane including two jet centerlines and its characteristic shock system, especially a cell structure formed secondly by interaction of two jets, are analyzed. The positions of the normal shock depending on the pressure ratios are also compared.

• Proceedings of the KIEE Conference
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• 2005.11a
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• pp.65-67
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• 2005

The Al electrode for OLED was prepared by Facing Targets Sputtering(FTS) system which can reduce the damage of organic layer. The Al thin films were deposited on the cell (Lif/EML/HTL/Bottom electrode : ITO) for examination the current-voltage properties of OLED with magnetic field distribution between two faced targets. Thickness and current-voltage properties of Al thin films are measured by ${\alpha}-step$ and semiconductor parameter analyzer (HP4156A), respectively.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2000.11a
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• pp.209-213
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• 2000

In this paper, the removal rate of NO in a reactor is measured first using nonthermal plasma generated from a wire-cylinder type reactor, then the spatial density distribution of NO particles is investigated using ICCD(Intensified Charged Coupled Device) camera. This research uses nonthermal plasma from electrical discharge to analyze the NO characteristics, and the measurements of NO discharge image and Distribution are performed using the ICCD camera to examine the NO characteristics more closely. Furthermore, the method of Laser Induced Fluorescence (LIF) is used to analyze the particular behavior of NO particles more specifically, to suggest a method of reducing exhaust gas, a serious environmental problem.

• 한국연소학회:학술대회논문집
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• 2003.12a
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• pp.19-26
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• 2003

Experimental measurements of flame structure and soot characteristics were performed for ethene inverse diffusion flames (IDF). IDF has been considered as the excellent flow field to study the incipient soot because soot particle do not experience the oxidation process. In this study, LIF image clarified the reaction zone of IDF with OH signal and PAH distribution. laser light scattering technique also identified the being of soot particle. To address the degree of soot maturing, C/H ratio and morphology of soot sample were investigated. From these measurements, the effect of flow residence time and temperature on soot inception could be suggested, and more details on soot characteristic in the IDF was determined according to fuel dilution and flame condition. The fuel dilution results in a decrease of temperature and enhancement of residence time, but the critical dilution mole fraction is existed for temperature not to effect on soot growth. Also, the soot inception evolved on the specific temperature and its morphology are independent of the fuel dilution ratio of fuel.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2001.11a
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• pp.165-166
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• 2001

HO$_2$ radical plays pivotal roles in the tropospheric $O_3$ formation chemistry. This radical oxidizes NO to NO$_2$ and thus HO$_2$ radical can lead to in-situ ozone formation. Numerous methods have been tried to measure concentrations of atmospheric HO$_2$ in gas phase. Detecting methods applied in the air are a chemical amplifier (Cantrell et al., 1996), FAGE (Fluorescence Assay with Gas Expansion) (Hard et al., 1984), and LIF (Laser-induced Fluorescence) (Stevens et al., 1994). These methods have been limited because of low sensitivity and interferences such as $O_3$, NO, and itself (Stevens et al.,1994). (omitted)

• 한국연소학회:학술대회논문집
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• 2006.04a
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• pp.128-134
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• 2006

A characterization of turbulent reacting flows has proved difficult owing to the complex interaction between turbulence, mixing, and combustion chemistry. There are many types of time scales in turbulent flame which can determine flame structure. This counter jet type premixed burner produces high intensity turbulence. The goal is to gain better insights into the flame structures at high turbulence. 6 propane/air flames gave been studied with high velocity fluctuation in bundle type nozzle and in one hole type nozzle. By measuring velocity fluctuation, turbulent intensity and integral length scale are obtained. And sets of OH LIF images were processed to see flame structure of the mean flame curvatures and flame lengths for comparison with turbulence intensity and turbulent length scales. The results show that the decrease in nozzle size generates smaller flow eddy and mean curvatures of the flame fronts, and a decrease in Damkohler number estimated from flow time scale measurement.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.203-203
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• 2011

Metastable statates, resonant states in 4s level and excited states in 4p level were investigated with a simple global model and examined by the LIF experiments. Metastable states exhibit an anomalous behavior with the plasma density, on the other hands, other states show monotonous increasing behaviors. It turns out that the metastable state can have such an anomalous behavior due to its special characteristic, electric dipole radiation forbidden. It is expected to resolve the ambiguity of previously reported metastable density behaviors and provide further understanding.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2256-2258
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• 1999

This paper describes preliminary discussions on spatial distribution of NO density, which is mostly contained in simulated NOx exhaust, between a wire-cylinder geometry discharge gaps by using Laser Induced Fluorescence(LIF) Spectroscopy, Spatial distribution of NO density will be measured with varying NO concentrations from 166 to 644 [ppm] and diameters of central electrode from 6 to 10mm. Pulsed Nd:YAG laser. Optical Parametric Oscillator(OPO), and Frequency Doubler are used to excite NO molecules to their excited state.

• Journal of ILASS-Korea
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• v.3 no.1
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• pp.10-18
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• 1998

To investigate the in-cylinder phenomena in a SI engine with 3 valves and pent-roof type combustion chamber, flow fields, fuel distributions, and flame propagations were measured in a single c!'tinder visualized engine. Flow fields were visualized by PTV system during the intake and compression process. Fuel distributions were measured by PLIF at the various engine conditions including the cold and hot engine conditions and the effect of air-shrouded injector on the fuel distribution was investigated also. In addition, flame propagation patterns were characterized.

• Journal of the Ergonomics Society of Korea
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• v.11 no.2
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• pp.3-13
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• 1992

Resultant compressions on the L5/S1 joint of six subjects were studied as they lif- ted light weights in sitting and standing work postures. The subjects activities were photographed and analysed later by a static biomechamical computer model. Statistically significant differences were found between the result of the two postures analyses. Sitting posture showed significantly high compressions on the joint when doing several material handling tasks having the same work loads from the hip joint. Therefore, it is recommended that working with light weights in standing is less hazardous than doint the same work sitting postures, although both the maximum compression forces are under the Action Limit suggested by NIOSH.