• 대한기관식도과학회:학술대회논문집
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• 대한기관식도과학회 2009년도 제51차 학술대회 초록집
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• pp.38-38
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• 2009

• 대한음성언어의학회:학술대회논문집
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• 대한음성언어의학회 2007년도 제26차 학술대회
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• pp.23-23
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• 2007

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1999년도 추계학술발표회요약집
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• pp.379.2-379
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• 1999

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2004년도 추계학술대회 논문집
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• pp.86-89
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• 2004

One most feasible way to measure the concentration field in the micro-channel is using micro-LIF(Laser Induced Fluorescence) method. However, an accurate concentration field at a given cross plane in a micro-channel has not been successfully achieved so far due to various limitations in the light illumination and fluorescence signal detection. The present study demonstrates a novel method to provide an ultra thin laser sheet beam having five(5) microns thickness by use of a micro focus laser line generator. The laser sheet beam illuminates an exact plane of concentration measurement field to increase the signal to noise ratio and considerably reduce the depth uncertainty. Nile Blue A was used as fluorescent dye for the present LIF measurement. The enhancement of the fluorescent intensity signals was performed by a solvent mixture of water $(95\%)$ and ethanol (EtOH)/methanol (MeOH) $(5\%)$ mixture. To reduce the rms errors resulted from the CCD electronic noise and other sources, an expansion of grid size was attempted from $1\times1$ to 3(3 or 5(5 pixel data windows and the pertinent signal-to-noise level has been noticeably increased accordingly.

• Current Optics and Photonics
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• 제5권5호
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• pp.554-561
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• 2021

Indocyanine green (ICG) is a cyanine dye that has been used in medical diagnostics based on fluorescence imaging, and in medical therapy based on the photothermal effect. It is important to systematically understand the photothermal effect and fluorescence characteristics of ICG simultaneously. By varying a number of conditions such as laser power density, laser irradiation wavelength, concentration of ICG solution, and exposure time of laser irradiation, the intensity properties of fluorescence and the temperature change induced by the photothermal effect are measured simultaneously using a charge-coupled-device camera and a thermal-imaging camera. The optimal conditions for maximizing the photothermal effect are determined, while maintaining a relatively long lifetime and high efficiency of the fluorescence for fluorescence imaging. When the concentration of ICG is approximately 50 ㎍/ml and the laser power density exceeds 1.5 W/cm², the fluorescence lifetime is the longest and the temperature induced by the photothermal effect rapidly increases, exceeding the critical temperature sufficient to damage human cells and tissues. The findings provide useful insight into the realization of effective photothermal therapy, while also specifying the site to be treated and enabling real-time treatment monitoring.

• 한국광학회지
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• 제5권2호
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• pp.245-251
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• 1994

고리형 공진기의 색소레이저에서 시계방향 모드와 반시계 방향 모드 사이에 나타나는 switching 현상을 펌프 매개변수 a, 폄프요동의 세기 Q 및 진동수폭 등을 변화시켜 Monte Carlo 방법으로 수치 계산하여 고찰하였다. 덧셈형 noise만 고려할 때와 이 noise에다 여기요동을 나타내는 곱셈형 색 noise를 포함시켰을 때 FPT분포에 미치는 영향을 조사하였다. 두 경우에 있어서 FTP의 분포는 짧은 시간영역에서는 0에서 상승하여 최대값에 도달하고, 긴 시간영역에서는 지수함수적으로 감소하는 경향은 같았으나 덧셈의 noise만 존재할 때에 비하여 곱셈의 색 noise가 포함될 때는 FPT가 감소하였다. 한편, 평균 FTP는 펌프매개변수 a의 증가와 더불어 증대하였으며 곱셈형 noise의 세기Q 및 진동수폭 $\GAMMA$가 증가할 때는 감소함을 알 수 있었다.

• 대한화학회지
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• 제55권2호
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• pp.169-176
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• 2011

N,N-bis(2,5-di-tert-butylphenyl) - 3,4,9,10 perylenebis(dicarboximide) 레이저 염료에 대한 전기화학적 연구가 0.1 M tetrabutyl ammonium perchlorate(TBAP)/1,2 dichloroethane($CH_2Cl-CH_2Cl$) 용액내에서 백금 전극을 이용하여 순환 전압-전류법 및 디지털 시뮬레이션 기술과 결합된 convolution-deconvolution 전압-전류법으로 수행되었다. 연구에 사용된 염료는 두개의 전자를 순차적으로 소모하며 radiacal anion과 dianion으로(EE 메커니즘) 환원되었다. 전위를 positive scan으로 전환하면, 이 화합물은 두 개의 전자를 잃고 산화된 뒤 빠른 응집 과정($EC_1EC_2$ 메커니즘)을 거치게 된다. 이 화합물의 전극 반응 경로, 화학 및 전기화학적 파라미터는 순환 전압-전류법과 convolutive 전압-전류법을 이용하여 측정되었다. 이렇게 구한 전기화학적 파라미터는 디지털 시뮬레이션 방법을 통하여 검증되었다.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2004년도 Proceedings of 2004 Korea-Japan Joint Seminar on Particle Image Velocimetry
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• pp.65-74
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• 2004

Measurement of concentration distributions of suspended particles in a micro-channel is out of the most crucial necessities in the area of Lab-on-a-chip to be used for various bio-chemical applications. One most feasible way to measure the concentration field in the micro-channel is using micro-LIF(Laser Induced Fluorescence) method. However, an accurate concentration field at a given cross plane in a micro-channel has not been successfully achieved so far due to various limitations in the light illumination and fluorescence signal detection. The present study demonstrates a novel method to provide an ultra thin laser sheet beam having five(5) microns thickness by use of a micro focus laser line generator. The laser sheet beam illuminates an exact plane of concentration measurement field to increase the signal to noise ratio and considerably reduce the depth uncertainty. Nile Blue A was used as fluorescent dye for the present LIF measurement. The enhancement of the fluorescent intensity signals was performed by a solvent mixture of water $(95\%)$ and ethanol (EtOH)/methanol (MeOH) $(5\%)$ mixture. To reduce the rms errors resulted from the CCD electronic noise and other sources, an expansion of grid size was attempted from $1\times1\;to\;3\times3\;or\;5\times5$ pixel data windows and the pertinent signal-to-noise level has been noticeably increased accordingly.

• 분석과학
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• 제8권4호
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• pp.865-868
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• 1995

The method of matrix-assisted laser desorption ionization mass spectrometry has been used to solve some bioanalytical problems, which is difficult to analyse by general methods. For the selection of proper laser wavelength and matrices, eight matriees was used with laser wavelength of 226 and 355nm. The result shows that with wavelength of 355nm better results could be obtained with most of the matrices. The molecular weight of eytochrome C, which was seperated by gel electrophoresis and electro-blotted onto NC membrane is determined by MALDI. The accuracy is better than 0.1%, which is much higher than that of SDS-PAGE. Protein mixture extracted from crude peanut oil is directly determined by MALDI. The molecuiar weight of its three components are determined, and the result also demonstrated that these proteins are in free manner. As proteins arc in 2S bond, with the traditional method, SDS-PAGE, it is not able to decide whether protein exists in combination mode or in free manner. In the technique of two phase aquesous solution, which is used for separating biomaterials, water soluble polymers stained with dyes are used in this technique. By the use of MALDI the number or the dye molecules react with the polymer PEG molecule are determined, and that is difficult to determined by other methods.

• Journal of Photoscience
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• 제11권2호
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• pp.55-59
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• 2004

The present investigation is an attempt to create an optimized protocol for a bactericidal modality of different powers of He-Ne laser radiation to eliminate periodontitis disease causing bacteria from dental plaques. Periodontitis is most prevalent infectious disease of men and caused by a limited number of Gram negative oral bacteria. Porphyromonas gingivalis and Streptococcus sanguis are the important bacteria responsible for periodontitis diseases. Effect on periodontitis disease causing bacteria were produced by the exposure of different powers of He-Ne laser light i.e. 9 mW, 17 mW and 26 mW of red colour of wavelength 632.8 nm in two different periods of time i.e. 10 min. and 20 min. in the presence of dye Methylene blue (MB) used as a photosensitizer. The results have been shown in terms of percentage inhibition of colony forming units (cfu.) of bacteria. This study has shown that maximum inhibition of cfu. were observed in Laser+MB-20 min. exposure time. This inhibition was followed by Laser+MB-10 min., but minimum inhibition was seen in Laser only at 10 min. exposure. In case of effect of methylene alone on the cfu. of bacteria, it was seen that MB have not shown more inhibition of cfu. and it had shown that the no. of cfu. are very similar to that of control. The above observation of the present study was seen in case of every 3 different type of used powers of laser for both the bacteria. Maximum percentage inhibition of cfu. were seen in case of 26mW powers of He-Ne laser, which was 67. 28% to 61.42% for Porphyromonas gingivalis and Streptococcus sanguis respectively. So, increasing the power of laser (safe range for dentistry is 3-30 mW) under conditions shows an increased percentage inhibition of cfu. Thus the present investigation may be a useful adjunct with mechanical debridement in the prevention of recolonization of subgingival lesions by pathogenic microorganisms which are harmful and drug resistant.