• Title/Summary/Keyword: LIF

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Measurement on the Methotrexate in L-${\alpha}$-Phosphatidylcholine Media by Light Sacttering (L-${\alpha}$-Phosphatidylcholine 매질에서 빔산란에 의한 Methotrexate의 측정)

  • Kim, Ki-Jun;Lee, Joo-Youb
    • Journal of the Korean Applied Science and Technology
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    • v.30 no.2
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    • pp.251-257
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    • 2013
  • The influences of Methotrexate as fluorophor, scatterer, absorber in turbid material by light scattering were interpreted for the scattered fluorescence intensity and wavelength, it has been studied the molecular properties by laser induced fluorescence spectroscopy. It has been found that the effects of optical properties in scattering media by the optical parameters((${\mu}_s$, ${\mu}_a$, ${\mu}_t$). The value of scattering coefficient ${\mu}_s$ is large by means of the increasing particles of L-${\alpha}$-Phosphatidylcholine, it has been found that the slope decays exponentially as a function of depth from laser source to detector. It may also aid in designing the best model for oil chemistry, laser medicine and application of medical engineering.

A Study on Effect of n-heptane Mixing on PAH and Soot Formation in Counterflow Ethylene Diffusion Flames (대향류 에틸렌 확산화염내 PAH 및 매연의 생성에 미치는 n-헵탄 혼합의 영향에 관한 연구)

  • Choi, Jae-Hyuk;Han, Won-Hui
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.18 no.1
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    • pp.55-60
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    • 2012
  • In order to investigate the effect of n-heptane mixing on PAH and soot formation, small amount of n-heptane has been mixed in counterflow ethylene diffusion flame. Laser-induced incandescene and laser-induced fluorescene techniques were employed to measure soot volume fraction and polycyclic aromatic hydrocarbon(PAH) concentration, respectively. Results showed that the mixing of n-heptane in ethylene diffusion flame produces more PAHs and soot than those of pure ethylene flame. However, signals of LIF for 20% n-heptane mixture flame were lower than that of pure ethylene flame. It can be considered that the enhancement of PAH and soot formation by the n-heptane mixing of ethylene can be explained by methyl($CH_3$) radical in the low temperature region. And it can be found that reaction rate of H radical for 10% n-heptane plays a crucial role for benzene formation.

NO Formation in Partially Premixed Counterflow Flames;Comparison of Computed and PLIF Results (부분예혼합 대향류 화염에서의 NO 생성특징;수치해석 및 PLIF 결과 비교)

  • Lee, Woong-Jae;Lee, Won-Nam;Cha, Min-Suk;Song, Young-Hoon
    • 한국연소학회:학술대회논문집
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    • 2000.05a
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    • pp.57-66
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    • 2000
  • OH radical and NO distributions have been measured in methane/air partially premixed counterflow flames(${\alpha}$=1.0, 0.8, 0.6) using PLIF technique. The results are discussed and compared with the numerical analysis results obtained under the same flame conditions. Measured OH and NO LIF signals agree with the computed concentration distributions. Both numerical and experimental results indicate that the structural change in a flame alters the NO formation characteristics of a partially premixed counterflow flame. The nitrogen dilution also changes flame structure, temperature and OH radical distributions and results in the decreased NO concentrations in a flame. The levels of decrease in NO concentrations, however, depends on the premixedness(${\alpha}$) of a flame. The larger change in the flame structure and NO concentrations have been observed in a premixed flame($\alpha$=1.0), which implies that the premixedness is likely to be a factor in the dilution effect on NO formation of a flame.

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An Experimental Study on the Self-excited Instabilities in Model Gas Turbine Combustor (모델 가스터빈 연소기내의 자발 불안정성에 관한 실험적 연구)

  • Lee, Min-Chul;Hong, Jung-Goo;Shin, Hyun-Dong
    • 한국연소학회:학술대회논문집
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    • 2004.11a
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    • pp.197-205
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    • 2004
  • Most of gas turbines is operated by the type of dry premixed combustion to reduce NOx emission and economize fuel consumption. However this type operation, combustion induced instability brought failure problems cause by high pressure and heat release fluctuations. Though there has been lots of studies since Lord Rayleigh to understand this instability mechanism and control the instabilities, none of them made matters clear. In order to understand the instability phenomena, a simple experimental study with dump combustor was conducted at the moderate pressure and ambient temperature conditions. From this model gas turbine combustor self-excited instabilities at the resonance mode(200Hz) and bulk mode(10Hz) were occurred and observed at the three points of view; pressure, heat release and equivalence ratio which are acquired by peizo-electric transducer, HICCD camera and acetone LIF respectively. From this results we could see the instability mechanism clear with the account of time scale analysis which explained by the propagation of pressure wave to the upward of mixture stream and convectional transfer of the equivalence ratio fluctuation by this pressure fluctuation.

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The performance of Bio-aerosol Detection System (BDS) with 405 nm laser diode (405 nm 광원을 이용한 생물입자탐지기의 에어로졸 분석성능)

  • Jeong, Young-Su;Chong, Eugene;Lee, Jong-Min;Choi, Kibong
    • Particle and aerosol research
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    • v.13 no.1
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    • pp.25-31
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    • 2017
  • This paper offer the characteristics for the detection and classification of biological and non-biological aerosol particles in the air by using laser-induced-fluorescence (LIF) based Bio-aerosol Detection System (BDS). The BDS is mainly consist of an optical chamber, in-outlet nozzle system, 405 nm diode laser, an avalanche photo detector (APD) for scattering signal and photomultiplier tubes (PMT) for fluorescence signals in two different wavelength range ; F1, 510-600 nm and F2, 435-470 nm. The detection characteristics, especially ratio of fluorescence signal intensity were examined using well-known components : polystylene latex (PSL), fluorescence PSL, $2{\mu}m$ of SiO2 micro sphere, dried yeast, NADH, ovalbumin, fungicide powder and standard dust. The results indicated that the 405 nm diode laser-based LIF instrument can be a useful bio-aerosol detection system for unexpected biological threaten alter in real-time to apply for dual-use technology in military and civilian fields.

Measurement of Liquid Fuel Film on the Cylinder Liner in an SI Engine Using an LIF Technique (레이저 유도 형광법을 이용한 가솔린 엔진의 실린더 벽면에 존재하는 연료액막 가시화)

  • Cho, Hoon;Min, Kyoung-Doug
    • Proceedings of the KSME Conference
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    • 2001.06d
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    • pp.25-30
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    • 2001
  • The liquid fuel film on the cylinder liner is believed to be a major source of engine-out hydrocarbon emissions in SI engines, especially during cold start and warm-up period. Quantifying the liquid fuel film on the cylinder liner is essential to understand the engine-out hydrocarbon emissions formation in SI engines. In this research, two-dimensional visualization was carried out to quantify liquid fuel film on the quartz liner in an SI engine test rig. The visualization was based on laser-induced fluorescence and total reflection. Using a quartz liner and a special lens, only the liquid fuel on the liner was visualized. The calibration technique was developed to quantify the fluorescence signal with the thickness gage and the calibration device. The fluorescence intensity increases linearly with increase in the fuel film thickness on the quartz liner. Using this technique, the distribution of the fuel film thickness on the cylinder liner was measured quantitatively for different valve lifts and injected fuel mass in the test rig.

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Depletion Kinetics of the Ground State CrO Generated from the Reaction of Unsaturated Cr(CO)x with O2 and N2O

  • Son, H.S.;Ku, J.K.
    • Bulletin of the Korean Chemical Society
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    • v.23 no.2
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    • pp.184-188
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    • 2002
  • Unsaturated $Cr(CO)_x(1{\leq}x{\leq}5)$molecules were generated in the gas phase from photolysis of $Cr(CO)_6$vapor in He using an unfocussed weak UV laser pulse and their reactions with $O_2$ and $N_2O$ have been studied. The formation and disappearance of the ground state CrO molecules were identified by monitoring laser-induced fluorescence(LIF) intensities vs delay time between the photolysis and probe pulses. The photolysis laser power dependence as well as the delay time dependence of LIF intensities from the CrO orange system showed different behavior as those from ground state Cr atoms, suggesting that the ground state CrO molecules were generated from the reaction between $O_2/N_2O$ and photo-fragments of $Cr(CO)_6$ by one photon absorption. The depletion rate constants for the ground state CrO by $O_2$ and $N_2O$ are $5.4{\pm}0.2{\times}10^{-11}$ and $6.5{\pm}0.4{\times}10^{-12}cm^3molecule^{-1}s^{-1}$, respectively.