• Journal of the Korean Chemical Society
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• v.44 no.4
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• pp.322-327
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• 2000

A new absorption spectrometric method for the determination of the Cr$_2O_7^{2-}$ ionin acidic media has been developed. The new method is based on the oxidation-reduction reaction of the HCr$O_4^-$ ion with H$_2$O$_2$forming a deep blue CrO(O$_2$) $_2$ andis coupled with a technique of flow injection analysis(FIA). The new method provides a linear calibration curve which accurately follows the Beer's law over a wide range of the analytical concentrations(2.0 ${\times}$ $10^{-6}$M~8.0 ${\times}$ $10^{-3}$M) of K$_2$Cr$_2$O$_2$. The sensitivity of the new method is approximately two times greater than the current method and the effects of the interfering substances such as V, Co, Ni, Fe, and Mn are almost negligible except Cu.

• Clean Technology
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• v.26 no.4
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• pp.293-303
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• 2020

According to the World Health Organization (WHO), air pollution is a typical health hazard, resulting in about 7 million premature deaths each year. Sulfur dioxide (SO2) is one of the major air pollutants, and the combustion process with sulfur-containing fuels generates it. Measuring SO2 generation in large combustion environments in real time and optimizing reduction facilities based on measured values are necessary to reduce the compound's presence. This paper describes the concentration measurement for SO2, a particulate matter precursor, using a wavelength modulation spectroscopy (WMS) of tunable diode laser absorption spectroscopy (TDLAS). This study employed a quantum cascade laser operating at 7.6 ㎛ as a light source. It demonstrated concentration measurement possibility using 64 multi-absorption lines between 7623.7 and 7626.0 nm. The experiments were conducted in a multi-pass cell with a total path length of 28 and 76 m at 1 atm, 296 K. The SO2 concentration was tested in two types: high concentration (1000 to 5000 ppm) and low concentration (10 ppm or less). Additionally, the effect of H2O interference in the atmosphere on the measurement of SO2 was confirmed by N2 purging the laser's path. The detection limit for SO2 was 3 ppm, and results were compared with the electronic chemical sensor and nondispersive infrared (NDIR) sensor.

• The Journal of Natural Sciences
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• v.9 no.1
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• pp.53-56
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• 1997

The structure of poly-$\beta$-hydroxybutyrate (PHB) in Chlorogloea fritschii was analyzed by FT-IR spectrometry under various conditions (phosphate starves or sufficient conditions). They exhibited characteristic absorption peaks for PHB, such as C=O stretching band at 1700-1800 $cm^-1$and C-H stretching bands at about 2900 $cm^-1$, however, the intensity of C-H stretching peaks, relative to the rest of the spectrum was increased under phosphate starved condition, which suggests that C. fritschii might produce another modified PHB polymer under phosphate starved condition.

• Analytical Science and Technology
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• v.12 no.5
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• pp.355-359
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• 1999

Trace cadmium was determined in urine by flame and nameless AAS. Inflame method, cadmium was extracted into MIBK from Cd-DDTC complex. In flameless method, samples were pretreated with 1%, Triton X-100. 1% $HNO_3$ and matrix modifier $Pd(NO_3)_2$. Analysis of cadmium was, performed at $450-750^{\circ}C$ ashing temperature by use of pyrocoated tubes. Results of analysis, flameless method superior in sample treatment and reproducibility to flame method and highest absorbance was obtained at $550^{\circ}C$ ashing temperature. 100 mg/L $Pd(NO_3)_2$ concentration. Proposed method were applied to the determination of cadmium in standard urine Lononorm-Metalle 3.

• Proceedings of the Optical Society of Korea Conference
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• 2000.08a
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• pp.86-87
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• 2000

최근 들어 희토류 원소(Rare earth elements)에 대한 학문적 가치와 산업적 응용에의 중요성에 대한 인식이 증대되면서 이들 원소에 대한 분광학적 연구가 활발하게 이루어지고 있다. 란탄족 원소(Lantanoid)로도 일컬어지는 6주기 3족 원소(원자번호 57~71번)인 희토류 원소들은 일반적으로 녹는점 및 끓는점이 상대적으로 높고 보다 복잡한 원자 구조를 가지고 있으므로 원자 분광학적 연구가 쉽지 않다. 따라서 이들 원소들에 대한 분광학적 정보를 얻기 위해서는 고효율의 원자 시료 발생 방법 및 고분해능의 원자 분광법이 요구된다$^{(1)}$ . (중략)

• Journal of the Society of Cosmetic Scientists of Korea
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• v.45 no.2
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• pp.105-116
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• 2019

Oil adsorption during hair or body washing is responsible for the hair conditioning. In this study, we established a method to extract oil from a substrate, and to determine amount of adsorbed oil upon substrate using a conventional absorption spectroscopy. We controlled the mole fraction of a surfactant in a mixture of anionic and amphoteric surfactants because that it induces the coacervate that regulates amount of adsorbed oil through the alteration of oil viscosity. Based on this, we established the optimized condition for adsorption and extraction for oil. UV absorbance were employed to estimate the amount of adsorbed oil using optical absorbance after extraction via adsorption. The estimation was confirmed by comparing with a mass analysis in HPLC and an adhesive energy in AFM. It has been proved that this method can be applied to all cases of oil adsorption from the results with various cationic polymers and a complex system of the polymers which regulate the oil adsorption.

• Journal of ILASS-Korea
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• v.9 no.4
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• pp.67-76
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• 2004

Diode laser absorption sensors are advantageous because they may provide fast, sensitive, absolute, and selective measurements of species concentration. These systems are very attractive for practical applications owing to its compactness, reasonable cost, robustness, and ease of use. In addition, diode lasers we fiber-optic compatible and thus enable simultaneous measurements of multiple species along a line-of-sight. Recent advances of room-temperature, near-IR and visible diode laser sources for telecommunication, optical data storage applications make it possible to be applied for combustion diagnostics based on diode laser absorption spectroscopy. Therefore, combined with fiber-optics and high sensitive detection strategies, compact and portable sensor systems are now appearing for variety of applications. The objectives of this research are to develop new gas sensing system and to verify feasibility of this system. Wavelength modulation spectroscopy has been demonstrated in these experiments and has a bright prospect to this diode laser system.

• Korean Journal of Optics and Photonics
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• v.15 no.1
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• pp.1-5
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• 2004

Tunable diode laser absorption spectroscopy was performed for analysis of the H$_2$$^{18}$ O/H$_2$$^{16}$ O isotope ratio of a water sample which was enriched by the membrane distillation method. In order to improve the signal-to-noise ratio, the wavelength modulation spectroscopic method was used with a lock-in amplifier. The fringe noise could be suppressed by using the FFT (Fast Fourier Transform) lowpass filter and the optimization of the modulation depth of the laser frequency. The maximum deviation of $\delta$-value was measured to be$\pm$4$\textperthousand$.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.55.1-55.1
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• 2010

대마젤란 은하에 속한 식쌍성의 시선속도 곡선을 완성하기 위하여 2009년 11월 칠레에 위치한 Cerro Tololo Inter-American Observatory (CTIO)의 1.5m 망원경과 R-C Spectrograph를 사용하여 중 분산 분광관측을 수행하였다. 분광관측은 380nm - 540nm 영역에서 $H_8,\;H_{\varepsilon},\;H_{\delta},\;H_{\Gamma},\;H_{\beta}$ 등의 흡수선을 관측하였다. 중분산으로 관측된 식쌍성의 각 구성원별에서 나오는 흡수선들은 구별되지 않으므로 이를 구별하기 위하여 구성원들의 Flux 비와 함께 gauss curves fitting 방법으로 각 흡수선들을 2개의 성분으로 분해하여 시선속도를 측정하고, 시선속도곡선을 완성하였다. 완성된 이중 시선속도 곡선은 Wilson & Devinney 차등 보정법으로 분석하여, 궤도 장반경, 질량비, 계의 시선속도 등을 구하였다. 또한 각 식쌍성들의 광도곡선을 분석하여 측광학적인 해를 구하고, 최종적으로 분광 및 측광관측의 해를 혼합하여 대마젤란은하 식쌍성들의 절대량을 구하였다. 이후 이를 바탕으로 거리를 구하여 기존에 발표된 마젤란은하의 거리와 비교하였다.

• Proceedings of the Optical Society of Korea Conference
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• 2000.08a
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• pp.76-77
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• 2000

포화흡수분광(saturated apsorption spectroscopy)$^{[1]}$ 은 원자나 분자의 도플러 선폭확대를 제거할 수 있는 고분해 분광법 중의 하나이다. 이 방법은 조사하려는 매질에 서로 반대방향으로 진행하는 펌프광과 조사광을 비추어, 펌프광의 주파수가 원자의 에너지 준위에 공진 될 때, 매질 내에서 조사광의 흡수가 달라지는 현상을 이용하는 것이다. 특히 알카리 원자의 경우, 바닥상태에 두 개의 초미세준위를 가지고 있고 들뜬상태의 수명이 짧으므로 약한 펌프광에 의해서도 쉽게 이 현상을 관찰할 수가 있다(그림 1 (a), 그림 2 (a)). (중략)