• 한국추진공학회지
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• 제9권4호
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• pp.55-65
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• 2005

에어 터보 램제트 엔진 연소기에서 연료와 공기의 혼합성능은 연소 효율과 안정성에 중요한 요인이 된다. 에어 터보 램제트 축소모형의 연소기에서 혼합기에 따른 혼합성능을 파악하기 위하여 두개의 꽃잎형 혼합기를 제작하였고, 각각에 대하여 연료 분포를 측정하였다. 2차원 연료 분포 측정에는 평면 레이저 유도 형광 기법을 사용하였다. 획득한 아세톤 형광 이미지는 이미지 처리 기법을 사용하여 정량적 연료 분포로 나타내었다. 이러한 연료 분포 이미지를 바탕으로 연료와 공기의 혼합성능이 좋은 혼합기를 알아내었다.

• 대한화학회지
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• 제29권3호
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• pp.265-270
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• 1985

희석 파라미터법을 이용한 X-선 형광분광법으로 주석슬랙중 Ta$_2$O$_5$, Nb$_2$O$_5$, SnO$_2$ 및 ZrO$_2$를 정량하였으며 그들의 분석결과를 표준검정곡선법으로 얻은 결과들과 비교하였다. 주석슬랙 시료와 주석슬랙과 비슷한 조성을 갖는 한개의 표준시료를 적당한 희석제(La$_2$O$_3$)로 1 : 1, 1 : 2, 1 : 3, 1 : 4로 각각 희석하였다. 원시료와 희석된 시료의 X-선 세기를 측정하여 희석 파라미터항이 포함된 계산식을 이용하여 함량을 계산하였다. 그 결과 분석값은 표준검정곡선법에 의한 기준값들과 잘 일치하고 있음을 확인하였다.

• 한국대기환경학회지
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• 제17권1호
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• pp.31-38
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• 2001

Ambient ge-phase $H_2O$$_2$(Hydrogen Peroxide) concentrations were measured at four sites in downtown Seoul Korea. These measurements were mad during winter and summer, February 14~19 and 12~17, 1997. $H_2O$$_2$concentrations were quantified by fluorescence using enzyms. $H_2O$$_2$ concentrations in winter were below the limit of detection and was much higher concentrations in summer. The mean of all observations was 264 ppt and the range measured was 23ppt~1856ppt. The results from the correlation analysis showed that the concentration of gasous $H_2O$$_2$is dependent on the other air pollutants(O$_3$, NO$_2$) and meteorological parameter(solar radiation).

• Journal of Mechanical Science and Technology
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• 제17권9호
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• pp.1371-1379
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• 2003

The effects of change in injection pressure on spray structure in high temperature and pressure field have been investigated. The analysis of liquid and vapor phases of injected fuel is important for emissions control of diesel engines. Therefore, this work examines the evaporating spray structure using a constant volume vessel. The injection pressure is selected as the experimental parameter, is changed from 22 MPa to 112 MPa using a high pressure injection system (ECD-U2). Also, we conducted simulation study by modified KIVA-II code. The results of simulation study are compared with experimental results. The images of liquid and vapor phase for free spray were simultaneously taken by exciplex fluorescence method. As experimental results, the vapor concentration of injected fuel is leaner due to the increase of atomization in the case of the high injection pressure than in that of the low injection pressure. The calculated results obtained by modified KIVA-II code show good agreements with experimental results.

• 동력기계공학회지
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• 제9권4호
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• pp.214-219
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• 2005

The effects of change in injection pressure on spray structure in high temperature and pressure field have been investigated. The analysis of liquid and vapor phases of injected fuel is important for emissions control of diesel engines. Therefore, this work examines the evaporating spray structure using a constant volume vessel. The injection pressure is selected as the experimental parameter, is changed from 72MPa to 112MPa by using a common rail injection system(ECD-U2). The images of liquid and vapor phase in the evaporating free diesel spray are simultaneously taken by exciplex fluorescence method. As a result, it can be confirmed that the distribution of vapor concentration is more uniform in the case of the high injection than in that of the low injection pressure.

• 동력기계공학회지
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• 제18권3호
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• pp.5-13
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• 2014

In order to control emissions from engine, it is necessary to understand the mixture formation process of diesel spray. In this study, analysis of diesel fuel(n-Tridecane, $C_{13}H_{28}$) spray under a high temperature and pressure was performed by a general-purpose program, ANSYS CFX release 11.0, and the results of these are compared with experimental results of diesel fuel spray using the Exciplex Fluorescence Method. The simulation results of diesel spray is analyzed by using the combination of Large-Eddy Simulation(LES) and Lagrangian Particle Tracking(LPT), and then injection pressure was selected as an analysis parameter. Consequently, it was found that the experimental results and the numerical results are consistent with each other, and then in order to investigate the behavior characteristics of evaporative diesel spray, the effectiveness of the use of CFX of commercial code is definitely validated.

• Journal of Photoscience
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• 제4권3호
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• pp.105-112
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• 1997

The fluorescence quenching of 2, 5-di-(5-tert-butyl-2-benzoxazolyl)-thiophene (BBOT) by aniline in five different solvents namely heptane, hexane, cyclohexane, dioxane and acetonitrile has been carried out at room temperature with a view to understand the quenching mechanisms. The experimental results show positive deviation in the Stern-Volmer plots in all the solvents. In order to interpret these results we have invoked the Ground state complex and sphere of action static quenching models. Using these models various rate parameters have been determined. The magnitudes of these parameters suggest that sphere of action static quenching model agrees well with the experimental results. Hence this positive deviation is attributed to the static and dynamic quenching. Further, with the use of Finite Sink approximation model, it was possible to check these bimolecular reactions as diffusion-limited and to estimate independently distance parameter R$^1$ and mutual diffusion coefficient D. Finally an attempt has been made to correlate the values of R$^1$ and D with the values of the encounter distance R and the mutual diffusion coefficient D determined using the Edward's empirical relation and Stokes-Einstein relation.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2019년도 춘계학술대회
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• pp.278-280
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• 2019

유세포 분석법은 단일 세포나 미세 입자에 대한 다양한 광학적 특성을 측정하여 이를 매개 변수로 나타내는 측정법이다. 이러한 매개 변수에는 세포의 크기, 입상도, 형광 강도 등이 있으며 이는 세포와 광원에서 조사한 빛의 물리적이며 광학적인 상호 작용에 의해 방사되는 빛에 따라 결정된다. 하지만 유세포 분석법은 고가이며 크기가 크고 다양한 형광염료의 사용이 제한적이라는 단점이 있다. 또한, 측정할 수 있는 다양한 데이터에 비해 사용자가 원하고자 하는 데이터는 한정적일 수도 있다. 이러한 특징은 비용/공간적으로 제한적인 연구 환경을 가진 연구자에게 있어서 어려운 점으로 다가오고 있다. 이에 본 연구는 소형의 발광다이오드와 포토다이오드를 이용하여 저가의 휴대용 형광측정 장치를 개발하고자 한다. 이는 누구나 제작하기 쉽도록 3D 프린터로 설계되었으며 광원과 필터 그리고 광센서의 교체가 가능하도록 설계하여 표적 세포 및 형광염료의 다양한 선택이 가능하다. 제안된 형광측정 장치를 통하여 형광처리가 된 세포를 다양한 세포 수로 분류하여 측정하였으며 그 결과, 측정된 형광의 세기가 세포의 농도에 따라 비례한 것을 보였으며 또한 높은 선형성을 보여주었다.

• Toxicological Research
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• 제25권4호
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• pp.189-193
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• 2009

Hypoxia inducible factor $1\alpha$ (HIF-$1\alpha$) is a potential marker of carcicnogenesis since it is overexpresssed in many human cancers such as brain, breast, and uterus, and its role has implicated in tumor cell growth and metastasis. In this study, we established a stable cell line that express green fluorescence protein (GFP)-fused hypoxia inducible factor $1\alpha$ (HIF-$1\alpha$) and evaluated the potential use of this cell line for assessment of carcinogenicity of chemical toxicants. Western blot analysis as well as fluorescence measurements showed that protein-level of GFP-HIF-$1\alpha$ was significantly enhanced in a dose-dependent manner upon treatment of hypoxia mimicking agents such as dexferrioxamine and $CoCl_2$. Well-Known tumor promoters such as mitomycin and methyl methanesulfonate. significantly induced the fluorescence intensity of GFP-HIF-$1\alpha$, whereas the known negative controls such as o-anthranilic acid and benzethonium chloride, did not. These results indicate that HIF-$1\alpha$ could be a biological parameter for detection of tumor initiators/promoters and suggest that the GFP-HIF-$1\alpha$ cell line is a useful system for screening of carcinogenic toxicants.

• Bulletin of the Korean Chemical Society
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• 제16권3호
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• pp.256-260
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• 1995

Laser induced fluorescence spectra of OH produced from photodissociation of $H_2O_2$ at 280-290 nm in the gas phase have been observed. By analyzing the Doppler profiles, the anisotropy parameter($\beta$ =-0.7) and the center of mass translational energy of the fragments have been measured. The measured energy distribution is well described by an impulsive model. The excited state leading to dissociation is found to be of 1Au symmetry. The dissociation from this state is prompt and direct with the fragment OH rotating in the plane perpendicular to the O-O bond axis.