• Journal of Environmental Science International
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• v.27 no.6
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• pp.437-445
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• 2018

Laser induced-exciplex-fluorescence (EXCIPLEX) proposed by Melton is used to visualize fuel vapor in spray combustion. However, in the EXCIPLEX method based on TMPD/naphthalene system, the TMPD : naphthalene ratio is strictly restricted to 1 : 9. In addition, fluorescence intensity due to the vapor phase is extremely weak. To overcome these drawbacks, we propose a new laser-induced-excimer fluorescence (EXCIMER) method to visualize the liquid and vapor phases simultaneously. The spatial distributions of liquid and vapor in fuel spray suspended by ultrasonic waves are compared using the EXCIPLEX and EXCIMER methods. The correlation between fuel vapor concentration and fluorescence intensity is experimentally investigated by measuring the fluorescence intensity of saturated vapor formed over liquid fuel at a controlled temperature. These experimental results indicate that the EXCIMER method is effective for evaluating fuel vapor visualization in spray combustion. Furthermore, the quantitative distribution of fuel vapor concentration can be correctly estimated by the EXCIMER method.

• Bulletin of the Korean Chemical Society
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• v.30 no.12
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• pp.3034-3038
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• 2009

A simple, rapid, practical and sensitive spectofluorimetric method was developed for the determination of trace amount of heparin (Hep). Under the Optimum conditions, we studied the interaction between NFLX-Ce$^{3+}$-Hep complex by using absorption and fluorescence spectra. It was observed that Hep remarkably enhance the fluorescence intensity of the NFLX-Ce$^{3+}$ complex at ${\lambda}$= 356 nm in the buffer solution of pH = 7.60 and the enhancement effect is shown to relate with the concentration of Hep. The linear range and detection limit for the determination of Hep was obtained. By the Rosenthal graphic method, the association constant (K) and binding numbers (N) of Hep with probe were investigated. This method is relatively free of interference from coexisting substances and successfully applied for the determination of heparin in heparin sodium injection samples. A suitable mechanism of fluorescence enhancement between NFLX-Ce$^{3+}$ and the NFLX-Ce$^{3+}$-Hep systems were proposed and discussed.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11c
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• pp.525-532
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• 2000

A new spectroscopic method for pesticide residues detection on agricultural products was developed. The general determination methods are high performance liquid chromatography (HPLC), gas chromatography (GC) or GC-mass spectrometry. They have provided relatively good detection limit and accuracy with complicated and time-consuming (5hrs above) procedures. In addition freshness is very important for evaluating qualities of agricultural products. This requires a simple and fast method for detection of pesticides. Reflectance, transmittance and fluorescence spectrometry of pesticides were tested using UV range because most of pesticides contain conjugation band in the molecular structures. Fluorescence spectrometry showed better sensitive to detect pesticide residues than did reflectance and transmittance spectrometry. Intensity and shape of fluorescence spectra showed different patterns with different structures of pesticides. Detection limit for fluorescence spectrometry was 0.1 ppm to 10 ppm depending on the structures of pesticides. Application of fluorescence spectrometry appears to be an easy method for detection of pesticide residues on agricultural products.

• The Journal of Advanced Prosthodontics
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• v.9 no.6
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• pp.432-438
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• 2017

PURPOSE. The purpose of this study was to evaluate the in vitro validity of quantitative light-induced fluorescence-digital (QLF-D) and laser fluorescence (DIAGNOdent) for assessing proximal caries in extracted premolars, using digital radiography as reference method. MATERIALS AND METHODS. A total of 102 extracted premolars with similar lengths and shapes were used. A single operator conducted all the examinations using three different detection methods (bitewing radiography, QLF-D, and DIAGNOdent). The bitewing x-ray scale, QLF-D fluorescence loss (${\Delta}F$), and DIAGNOdent peak readings were compared and statistically analyzed. RESULTS. Each method showed an excellent reliability. The correlation coefficient between bitewing radiography and QLF-D, DIAGNOdent were -0.644 and 0.448, respectively, while the value between QLF-D and DIAGNOdent was -0.382. The kappa statistics for bitewing radiography and QLF-D had a higher diagnosis consensus than those for bitewing radiography and DIAGNOdent. The QLF-D was moderately to highly accurate (AUC = 0.753 - 0.908), while DIAGNOdent was moderately to less accurate (AUC = 0.622 - 0.784). All detection methods showed statistically significant correlation and high correlation between the bitewing radiography and QLF-D. CONCLUSION. QLF-D was found to be a valid and reliable alternative diagnostic method to digital bitewing radiography for in vitro detection of proximal caries.

• Journal of Photoscience
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• v.12 no.3
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• pp.143-147
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• 2005

The simultaneous determination of harman, harmaline and norharman has been described using synchronous fluorescence technique. The method has been based on their natural fluorescence. It is difficult to analyze and determine their contents by conventional fluorescence method because of their similar molecular structures. The synchronous spectrum, maintaining a constant wavelength difference of ${\Delta}{\lambda}=185nm$ between the excitation and emission monochromators, was selected as optimum to perform the determination. The method was also performed in aqueous medium at pH 4.0 and in presence of sodium dodecyl sulfate (SDS), $1{\times}10^{-5}M$. Under the optimum conditions, each analyte has the linear determination range of $1{\times}10^{-7}M-\;1{\times}10^{-4}M$.

• Tribology and Lubricants
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• v.29 no.1
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• pp.51-55
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• 2013

In this work, a new fluorescence emission measurement technology was introduced and experimentally compared with other measurement methods, such as the titration method and IR spectroscopy, to validate it for the oil oxidation measurement of electrical insulating oil. The oxidation characteristics of insulating oil were found to be fairly represented by the titration method and IR spectroscopy, and the results are comparable to a change in the fluorescence emission ratio that is defined as the shift in fluorescence intensity in the measured wavelength range. The result also shows that by the measurement of fluorescence emission ratio, it is possible to detect the oxidation of oil relatively earlier than by other methods. This study suggests that the developed technology can provide sufficient information for evaluating the insulating oil quality, and that the developed FER sensor can be used as an effective condition monitoring device of electrical insulating oil oxidation.

• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.1
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• pp.313-324
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• 1997

The aim of the present study was to describe an safe and convenient method for the early detection of enamel caries using laser fluorescence. Fluorescence from natually carious lesion of human teeth illuminated by an argon laser(488nm) was observed and photographed using barrier filter. Intact enamel was found to fluorescence with a yellowish light. Whereas, incipient caries lesions in the enamel were dearly visible as dark areas in contrast to the fluorescence surroundings. For evaluation of accuracy of this method, lesion depth measured by the laser fluorescence in light microscope was compared with that polarizing microscope. The results from the present study can be summarized as follows : 1. Enamel caries of smooth surface was observed as pale white spot and undefined outline in ordinary light. Whereas, lesion was clearly visible as dark spot in laser fluorescence. 2. There was no difference between ordinary light view and laser fluorescence in occlusal surface and interproximal surface. 3. There was no significant difference between the lesion depth observed by laser fluorescence with light microscope and polarizing microscope. Apparent correlation exists between two groups.

• Bulletin of the Korean Chemical Society
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• v.26 no.2
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• pp.268-272
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• 2005

Different detection characteristics of fluorescence immunochromatography method and high performance liquid chromatography (HPLC) method for the analysis of cyanobacterial toxins were studied. In particular, low and high limits of detection, detection time and reproducibility and detectable microcystin species were compared when fluorescence immunochromatography method and high performance liquid chromatography method were applied for the detection of microcystin (MC), a cyclic peptide toxin of the freshwater cyanobacterium Microcystis aeruginosa. A Fluorescence immunochromatography assay system has the unique advantages of short detection time and low detection limit, and high performance liquid chromatography detection method has the strong advantage of individual quantifications of several species of microcystins.

• Korean Journal Plant Pathology
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• v.11 no.2
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• pp.101-106
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• 1995

Deep blue fluorescence of resorcin blue-stained callose was observed only in the potato leafroll virus (PLRV)-infected potato plants, but not in other potato viruses investigated. The plant sections stained with aniline blue showed non-specific fluorescence regardless of PLRV infection, which means that aniline blue is not suitable for the staining of callose induces by PLRV infection. The fluorescence of resorcin blue-stained callose was more easily detectable than autofluorescence by a direct fluorescence detection method because of its deep blue color. The lateral branch of lower leaves was turned out to be the best material for fluorescence observation of all plant parts tested. In comparison of diagnostic efficacy of this technique to enzyme-linked immunosorbent assay (ELISA), PLRV infected potato plants showed corresponding increment of the fluorescence of resorcin blue stained callose as absorption values in ELISA increased. In the future, the criteria measuring the fluorescence objectively are thought to be determined for the practical application to the diagnosis of potato leafroll disease.

• Proceedings of the Optical Society of Korea Conference
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• 2007.07a
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• pp.35-36
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• 2007

We report a probe using a single double clad fiber (DCF) for fluorescence spectroscopy. Bidirectional separate transmission for excitation and fluorescence light in a single fiber was implemented. A DCF coupler made by side-polished method could extract none but the collected fluorescence signals propagating in inner cladding mode, thereby diminishing the interference of silica background generated by the excitation in core mode. The experimental results show that the fluorescence spectra of biological tissues obtained using the DCF probes have much less silica background than using a standard multiple-mode fiber.