• Proceedings of the Optical Society of Korea Conference
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• 2000.08a
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• pp.214-215
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• 2000

레이저로 발생시킨 플라즈마의 분광학적인 분석은 유용한 분석기술로 평가되고 있다. 이러한 플라즈마를 발생시키는데 있어서 Q-switched 레이저를 많이 사용되고 되고 있으나, Q-switch된 레이저로 발생시킨 플라즈마 복사광의 특성은 주변 분위기에 의해 매우 큰 영향을 받는다. 특히 대기압인 공기분위기에서 레이저로 발생된 플라즈마의 분광특성은 강하고 연속적인 background가 포함되고, 자체적으로 흡수되고, 넓게 퍼진 분광선들이 생성된다. 이는 레이저 발생 플라즈마를 통해 성분을 분석할 경우에 적합하지 않다. (중략)

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.6
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• pp.519-526
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• 2018

In order to analyze space resources, it had to be brought to earth. However, using laser-induced breakdown spectroscopy(LIBS) and Raman spectroscopy, it is possible to analyze qualitative and quantitative analysis of space minerals in real time. LIBS is a spectroscopic method in which a high energy laser is concentrated on a material surface to generate a plasma, and the emitted light is acquired through a spectroscope to analyze the atomic composition. Raman spectroscopy is a spectroscopic method that analyzes the molecular structure by measuring scattered light. These two spectroscopic methods are complementary spectroscopic methods for analyzing the atoms and molecules of unknown minerals and have an advantage as space payloads. In this study, data were analyzed qualitatively by using principal component analysis(PCA). In addition, a mixture of two minerals was prepared and a quantitative analysis was performed to predict the concentration of the material.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.608-611
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• 2011

Laser-induced combustions and explosions generated by high laser irradiances were explored by Laser-Induced Breakdown Spectroscopy (LIBS) in rich, and stoichiometric conditions. The laser used for target ablation is a Q-switched Nd:YAG laser with 7 ns pulse duration at wavelength of 1064 nm laser energies from 40 mJ to 2500 mJ ($6.88{\times}10^{10}-6.53{\times}10^{11}\;W/cm^2$). The plasma light source from aluminum detected by the echelle grating spectrometer and coupled to the gated ICCD(a resolution (${\lambda}/{\Delta}{\lambda}$) of 5000). This spectroscopic study has been investigated for obtaining both the atomic signals of aluminum (fuel) - oxygen (oxidizer) and the calculated ambient condition (plasma temperature and electron density). The essence of the paper is observing specific electron density ratio which can support the processes of combustion and explosion between ablated aluminum plume and oxygen from air by inducing high power laser.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.6
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• pp.523-530
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• 2017

Laser-Induced Breakdown Spectroscopy (LIBS) which a plasma is irradiated at a specific wavelength depending on the material when a high-energy laser is irradiated, and a Raman spectroscopy which measures rotation and vibration in molecules as light-scattering phenomenon occurs, are attracting attention as a space exploration technology because of the advantages of high accuracy and real-time analysis, and the ability to perform long-range detection. In this study, the tendency of the laser spectrum according to the change of the soil component was analyzed by laser spectroscopy and the two - dimensional chemical distribution was conducted based on the trend of laser spectrum. We have also established the environment of Mars (4-7 torr) and lunar atmosphere (<1 torr) in experimental setup, to prove that it is possible to measure by difference of soil chemical composition using LIBS and Raman spectroscopy even in artificial space environment.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.9
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• pp.789-795
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• 2016

Laser-induced combustions and explosions generated by high laser irradiances were explored by Laser-Induced Breakdown Spectroscopy (LIBS). The laser used for target ablation is a Q-switched Nd:YAG laser with 7 ns pulse duration at wavelength of 1064 nm laser energies from 40 mJ to 2500 mJ ($6.88{\times}10^{10}-6.53{\times}10^{11}W/cm^2$). The plasma light source from aluminum detected by the echelle grating spectrometer and coupled to the gated ICCD(a resolution (${\lambda}/{\Delta}{\lambda}$) of 5000). This spectroscopic study has been investigated for obtaining both the atomic/molecular signals of aluminum-oxygen and the calculated ambient condition such as plasma temperature and electron density. The essence of the paper is observing specific electron density ratio which can support the processes of chemical reaction and combustion between ablated aluminum plume and oxygen from air by inducing high laser energy.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.3
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• pp.257-259
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• 2003

본 논문은 다이오드 레이저와 광 다이오드를 사용한 이중 빗살형 다이오드 레이저 비색 분광기를 개발하여 항균 성분의 양이온 계면 활성제로 널리 사용되고 있는 cetylpyridinium chloride(CPC)의 농도를 측정하였다 분광기의 안정도는 광원의 세기, 감도, 재현성을 측정한 예비 실험을 통하여 검증이 되었다 또한 상용화된 UV/VIS분광기와의 비교 결과를 나타내었다. 다이오드 비색 분광기는 3×10/sup -5/M에서 1.1×10/sup -4/M의 CPC 농도 범위에서 0.9635의 상관계수를 나타내었다. 이러한 결과는 CPC의 농도 분석을 위한 간편한 다이오드 레이저 비색 분광기 개발의 가능성을 나타내었다.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.236-237
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• 2002

원자력 발전소에서 사용되는 연료의 효율을 증가시키기 위해서는 반응로에서 연소된 연료에 잔존하는 미량의 란탄족 (lanthanide)과 악티늄족 (actinide) 원소를 측정하고, 동위원소 성분비를 분석하는 작업이 필요하다. 이러한 미량원소 측정에는 흡수분광학 (absorption spectroscopy) 방법이 주로 사용되고 있다. 최근 들어 단일 종 모드 (single-longitudinal mode) 반도체 레이저가 개발되면서 미량원소 분석을 위한 분광 기술이 급속히 발전하고 있다. 반도체 레이저는 동작시킬 때 전력소모가 적고, 설치 공간이 작다는 점 때문에 현장 적용이 용이하므로 미량원소 측정 연구의 광원으로 많이 활용되고 있다. (중략)

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.137-146
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• 2004

Laser Induced Breakdown Spectroscopy(LIBS) system is being developed as an in-situ analysis system for the radioactive waste glass in the cold crucible melter. In order to complete the LIBS system, a spectrometer, a detector, and a laser were structured. An ESA 3000 (LLA Instruments GmbH, Germany) including a calibrated Kodak KAF-1001 CCD detector was selected as the spectrometer. A Q-switched Nd-YAG Brilliant(Quantel, France) laser was selected as an energy source. As the first research stage, the excitation temperatures of Fe(I) as a function of the detector's delay intervals(500, 1000, 1500, 2000ns) were evaluated using the Einstein-Boltzmann equation. The optimized excitation temperature of Fe (I) was 7820k at the delay time of 1500㎱ using the 532nm Nd-YAG laser pulse. This LIBS system will be optimized under the real environment vitrification facility in the near future and then used to be in-situ analyzed the glass compositions in the melter qualitatively.

• Korean Journal of Optics and Photonics
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• v.31 no.3
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• pp.125-133
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• 2020

An innovative method for separating overlapping latent fingerprints, using laser-induced plasma spectroscopy (LIPS) combined with multivariate analysis, is reported in the current study. LIPS provides the capabilities of real-time analysis and high-speed scanning, as well as data regarding the chemical components of overlapping fingerprints. These spectra provide valuable chemical information for the forensic classification and reconstruction of overlapping latent fingerprints, by applying appropriate multivariate analysis. This study utilizes principal-component analysis (PCA) and partial-least-squares (PLS) techniques for the basis classification of four types of fingerprints from the LIPS spectra. The proposed method is successfully demonstrated through a classification example of four distinct latent fingerprints, using discrimination such as soft independent modeling of class analogy (SIMCA) and partial-least-squares discriminant analysis (PLS-DA). This demonstration develops an accuracy of more than 85% and is proven to be sufficiently robust. In addition, by laser-scanning analysis at a spatial interval of 125 ㎛, the overlapping fingerprints were separated as two-dimensional forms.

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.222-223
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• 2000

희토류 (또는 란탄족) 원소들은 주기율표상에 원자 번호 57번부터 71번까지 15종의 원소들의 총칭이다. 일부 희토류 원소는 감속재를 비롯한 원자로의 재료로 사용되고 있으며, 대부분의 희토류 원자 스펙트럼은 원자력 발전소에서 사용한 연료의 폐기물 처리에 관련된 각종 연구에 이용되고 있다. 따라서 이 원소들에 대한 원자 분광학적 연구는 원자력 산업 응용 분야에서 중요하게 인식되고 있다. 특히, 레이저를 이용한 분광학적 기술은 이 원소들의 정량 분석에 있어 주성분과 비교적 적은 양 및 극미량 수준의 시료 분석에 가장 유용하게 이용되고 있다. (중략)