• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.3
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• pp.579-583
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• 2012

We have designed the small particle detection system. The scatteing effect of light was used to detect small particle. The fabricated system consisted of laser diode, lens, pin hole, and photo detector. The aperture, lens, and photo detector were optimized to improve the performance of detection system. The fabricated detection system detected the scattered light by small particle entering into detection system and its response time was fast.

• Journal of Environmental Science International
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• v.27 no.5
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• pp.309-317
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• 2018

In this study, a laser sheet technique and PLIF (Planar laser-induced fluorescence) are applied to a laboratory-scale pulverized coal burner of the open type, and the spatial relationship of the pulverized coal particle zone and the combustion reaction zone is examined by simultaneous measurement of Mie scattering and OH-LIF images. It is found that this technique can be used to investigate the spatial relationship of the combustion reaction zone and pulverized-coal particles in turbulent pulverized-coal flames without disturbing the combustion reaction field. In the upstream region, the combustion reaction occurs only in the periphery of the clusters where high-temperature burned gas of the methane pilot flame is entrained and oxygen supply is sufficient. In the downstream region, however, combustion reaction can be seen also within clusters of pulverized-coal particles, since the temperature of pulverized-coal particles rises, and the mixing with emitted volatile matter and ambient air is promoted.

• Journal of Mechanical Science and Technology
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• v.15 no.12
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• pp.1699-1710
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• 2001

The characteristics of methanol and methanol blended (M85) sprays were investigated under atmospheric conditions at various temperature, ranging from on-vaporizing to vaporizing ambient conditions (298∼353 K). From laser scattering images, the macroscopic characteristics of the spray, such as the spray tip penetration and the spray angle, were determined. Entropy concept was introduced to represent homogeneity and PIV analysis was adopted to determine the fluid dynamic information at each location of the spray. The correlation between entropy and vorticity strength enabled us to find their relations. The effect of ambient composition, mainly of viscous effect as affected by CO$_2$levels, was investigated using PIV and entropy analysis. Spray width and entropy value were found to tend to decrease at increased CO$_2$levels.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.178-178
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• 2012

Neutral atom temperature was measured by Laser Rayleigh scattering method using neutral depletion by neutral heating with ideal gas law in Inductively coupled plasma. We observed sudden pressure change when plasma is turned on and off. We analyzed mechanism of neutral heating by employing zero-dimensional neutral and ion energy balance model simultaneously. The results showed that neutral atom temperature increase with ion density. The mechanism of neutral atom heating and cooling is mainly dominated by ion-neutral collision including elastic and charge-exchange collision and by wall cooling respectively.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.5
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• pp.86-95
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• 2000

A modified spray impingement model has been developed, which is assessed against experiments for the impinging sprays on the small combustion chamber at various gas pressures. To investigate spray behaviors in the diesel combustion chamber, a transparent constant-volume chamber is made which is similar to the combustion chamber of the real diesel engine. The chamber is pressurized by N2 gas from 0 bar to 20 bar to find the effects of ambient pressures. The behaviors of spray injected into this chamber and dispersed after impingement on the cylinder wall is measured two-dimensionally using laser sheet Mie scattering method. The physical submodels have been properly modified to improve the prediction capability of original KIVA code to describe the spray behaviors after impingement on the curved cylinder wall. In terms of spray dynamics and evolution. numerical results give qualitatively good agreements with experimental data.

• Journal of ILASS-Korea
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• v.7 no.3
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• pp.31-37
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• 2002

In previous study, diesel-methanol stratified injection system is manufactured and applied to a D.I. diesel engine in order to realize combustion improvement using methanol, which is oxygenated fuel with large latent heat. We know that NOx and soot is reduced by stratified injection of diesel fuel-methanol. Therefore, in the present study, combustion diagnosis using optical measurement is tried to make clear effect of methanol on simultaneous reduction of NOx and soot. Two-color method is used to measure flame temperature and KL value, which is approximately proportional to the soot consentration along the optical path. Laser induced scattering method was used to measure distribution of soot at two dimensional area. Also, it is compared exhaust characteristics of NOx and soot with results of optical measurement.

• Proceedings of the Optical Society of Korea Conference
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• 2008.02a
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• pp.427-428
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• 2008

In this paper, we propose an BRDF measurement method based on laser light scattering, which is very effective for roughness measurement. The measurement setup has a very simple configuration, which consists of a collimated green laser, a detector. The experimental tests show that the BRDF measurement has difference between good Au Pad and bad Au Pad.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.2
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• pp.144-148
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• 2013

In this paper, the ultra water-repellent thin films were prepared by RF PECVD. On the basis of surface morphology, chemical bonding states and plasma diagnostics, a formation model of clusters for the ultra water-repellent films was discussed from considerations of formation process and laser scattering results. Moreover, using laser scattering method, the relative change of quantity of nano-clusters or size of agglomerates could be confirmed. From the results, the films were deposited with nano-clusters and those of agglomerates, which formed in organosilicon plasma, and formation of agglomerates were depended on the deposition time.

• Bulletin of the Korean Chemical Society
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• v.8 no.5
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• pp.403-405
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• 1987

A dynamic laser light scattering system has been constructed using a personal computer. The intensity of the scattered light was detected with a photomultiplier tube and a photon counter. The BCD output of the photon counter which is proportional to the intensity of scattered light is fed into a personal computer via an interface card. The personal computer was programmed as an autocorrelator in machine language. The data acquisition rate of the system was about 600 samples/s which is adequate for studies on the molecular dynamics of concentrated polymer solutions, polymer latices with large particle size, and polymer glass systems. The constructed system was tested with polystyrene latex and the measured diameter of the latex particle agrees well with the supplier's value.

• Proceedings of KOSOMES biannual meeting
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• 2018.06a
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• pp.201-201
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• 2018