• Current Optics and Photonics
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• 제7권6호
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• pp.761-765
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• 2023

We analyzed the absorption spectra of acetone in the 3.37 ㎛ mid-infrared range using the off-axis integrated cavity output spectroscopy technique to develop a real-time, in-line breath analysis device. The linear relationship between acetone concentration and absorption increase was confirmed as 0.32%/ppm, indicating that the developed device allows for a quantitative analysis of acetone concentration in exhaled breath. To further confirm the feasibility of using our device for breath analysis, we measured the acetone concentration of human breath samples at the sub-ppm level.

• 한국진공학회지
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• 제13권2호
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• pp.59-64
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• 2004

반도체 레이저를 광원으로 사용하는 원자흡수분광 방법으로 금속증기의 증착 공정을 감시하는 연구를 수행하였다. 전자빔 가열 방식을 이용하여 gadolinium (Gd) 금속을 대량으로 증발시켰다. 파장 영역이 770-794 nm (중심파장 780 nm)인 반도체 레이저빔과 388-396 nm 영역의 제 2 고조파 빔을 진공용기에 입사시켜 증발되는 금속증기의 원자흡수 스펙트럼을 실시간으로 기록하였다. 흡수 스펙트럼을 분석하여 증기의 원자밀도를 구했다. 전자빔 출력을 변화시키면서 측정한 원자밀도를 수정 결정 모니터 장치를 사용하여 측정한 증착률과 비교하였다. 산업적으로 많이 사용되는 Ti 등의 증착 공정 감시에 이 실험에서 구현한 레이저 분광장치를 적용할 수 있다는 것을 제시하였다.

• Journal of the Optical Society of Korea
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• 제7권3호
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• pp.174-179
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• 2003

We construct a four-level system where a metastable state is included in an $Er^{3＋}$ Doped Yttrium aluminum garnet (YAG) crystal. Because of the action of the coherent field, the traditional light amplification with inversion can be exhibited with remarkable variation. As a result, we propose a method to achieve the gain equalization by atomic coherence. At the same time, we find that the high index of refraction accompanied by vanishing absorption can also be reached in this model. We also find that a higher index of refraction with zero absorption can be easily obtained when the coherent field is off resonance.

• Journal of Nutrition and Health
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• 제4권3호
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• pp.1-4
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• 1971

Zinc is an essential trace element. Previos methods for the determination of zinc in serum have been difficult and reported findings must be treated with caution. The normal range of zinc in serum varies significantly according to different methods and author. The scope of this work was to establish the normal range of zinc in serum values in healthy Korean persons. Methods are described for the determination of zinc in serum diluted ten-fold with deionised water using Hitachi Model 207, atomic absorption spectrophotometer. The values of zinc in serum of 23 healthy Korean persons by atomic absorption spectroscopy ranged from 87.6 to $131.2\;{\mu}g/100\;ml$ with the mean value $109.1\;{\mu}g/100\;ml$ and standard deviation 10.86. In this method, satifactory result was obtained with regard to the coefficient variation and recoveries of added zinc in the measurenents.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.5-8
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• 2000

The population density of excited species in dc, rf and laser ablation plume plasmas has been measured using laser absorption spectroscopy. It was shown that, when the plasma was modulated by on and off with, the sensitivity and signal to noise (S/N) ratio became high. For example, the atomic O(3$^{5}$ S$^{o}$ $_2$) Population density, No* in $O_2$/He mixtures was obtained by the highest S/N ratio at a frequency of 2.7kHz. In a 20Torr room air, the lowest No* level to be detectable was shown to be an order of 10$^{7}$ cm$^{-3}$ . The population densities of resonance Ar(1S$_2$) and Xe(1S$_4$) levels were also measured in barrier discharges and laser ablation plasmas.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2002년도 추계학술발표회요약집
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• pp.319.2-319
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• 2002

Synchrotron-based X-ray absorption spectroscopy has been applied to determine the changes in bulk oxidation state of uranium oxides in molten salt. From an analysis of XANES data, one can determine the cahnges in bulk oxidation-state of U compounds in salts(LiCl/KCl). XAFS spectroscpy is a powerful tool for probing the changes in valence state and structure of uranium compounds in colten salt as well as in noncrystalline form and doped in other matrices.

• 한국광과학회:학술대회논문집
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• 한국광과학회 1999년도 학술대회지
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• pp.89-90
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• 1999

• 한국광학회지
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• 제15권1호
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• pp.1-5
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• 2004

분리막을 이용한 산소-18 분리실험에서 분리된 시료의 동위원소 성분비 분석을 위해 다이오드 레이저 흡수분광장치를 구성하였다. 흡수신호의 신호 대 잡음비를 높이기 위해 lock-in증폭기를 사용한 파장변조 분광법을 채택하였다. 레이저의 주파수 변조폭 최적화와 FFT 저역통과 필터링을 통해 다중반사흡수셀에서 발생하는 간섭무늬 잡음을 줄였다. 산소-18에 대한 흡수분광장치의 최대편차는 $\pm$4$\textperthousand$로 측정되었다.

• Environmental Engineering Research
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• 제21권3호
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• pp.247-255
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• 2016

Ten trace elements (Mg, Ca, V, Cr, Mn, Fe, Cu, Zn, Mo, and Cd) were determined in seven traditionally used wild medicinal plants of the Nagas in the North-East India viz Cynoglossum furcatum Wallich, Elsholtzia blanda Bentham, Lycopodium cernuum Linnaeus, Potentilla fulgens Wallich ex Hooker, Swertia macrosperma C.B. Clarke, Thalictrum foliolosum DC and Valeriana jatamansi Jones. Plant samples were dried, weighed, digested and analyzed for their mineral distribution level ranging from trace to major elements by graphite furnace-atomic absorption spectroscopy. All the medicinal herbs studied were found to contain the ten elements analyzed. The elemental concentration is given in mg/kg. Mg and Ca are present in high concentrations in both the roots and leaves of the plant samples. Among trace transition metals Fe had the highest concentration, followed by Mn, Cr, Cu, V, Zn, and Mo. Analysis showed that the toxic Cd element was at a lower concentration and is within the permissible limit of FAO/WHO, California standards and United States Pharmacopeia Limit for Nutritional Supplements.

• Bulletin of the Korean Chemical Society
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• 제23권4호
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• pp.545-549
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• 2002

A simple and rapid technique for the separation and preconcentration of lead in water and biological samples has been devised. Preconcentrationis based on the depositionof analyte onto a column packed with dithizone immobilized on sodium dodecyl sulfate coated alumina at pH $\geq$ 3. The trapped lead is eluted with 5 mL of 4 M nitric acid and determined by flame atomic absorption spectroscopy. A sample of 1 L, results in a preconcentration factor of 200 and the precision at 20${\mu}g$ $L^{-1}$ is 1.3%(n=8). The procedure is applied to tap water, well water, river water, vegetable extract and milk samples, and accuracy is assessed through recovery experiments and by independent analysis by furnace atomic absorption.