• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.12
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• pp.1013-1020
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• 2020

Spark-induced breakdown spectroscopy (SIBS) utilizes an electric spark to induce a strong plasma for collecting atomic emissions. This study analyses the potential for usinga compact SIBS instead of conventional laser-induced breakdown spectroscopy (LIBS) in discriminating rocks and soils for planetary missions. Targeting bulky solids using SIBS has not been successful in the past, and therefore a series of optimizations of electrode positioning and electrode materials were performed in this work. The limit of detection (LOD) was enhanced up to four times compared to when LIBS was used, showing a change from 78 to 20 ppm from LIBS to SIBS. Because of the higher energy of plasma generated, the signal intensity by SIBS was higher than LIBS in three orders of magnitude with the same spectrometer setup. Changing the electrode material and locating the optimum position of the electrodes were considered for optimizing the current SIBS setup being tested for samples of planetary origin.

• Journal of the Korean Chemical Society
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• v.54 no.5
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• pp.573-578
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• 2010

In this study, iron(III)-2,4-dihydroxysalophen chloride (Fe(2,4-DHSalophen)Cl), has been synthesized by combination of 2,4-dihydroxysalophen (2,4-DHSalophen) with $FeCl_2$ in a solvent system. This complex combination was characterized using UV-vis and IR spectroscopies. Subsequently, the interaction between native calf thymus deoxyribonucleic acid (ct-DNA) and Fe(2,4-DHSalophen)Cl, was investigated in 10 mM Tris/HCl buffer solution, pH 7.2, using UV-visible absorption and fluorescence spectroscopies, thermal denaturation technique and viscosity measurements. From spectrophotometric titration experiments, the binding constant of Fe(2,4-DHSalophen)Cl with ct-DNA was found to be $(1.6{\pm}0.2){\times}10^3\;M^{-1}$. The fluorescence study represents the quenching effect of Fe(2,4-DHSalophen)Cl on bound ethidium bromide to DNA. The quenching process obeys linear Stern-Volmer equation in extended range of Fe(2,4-DHSalophen)Cl concentration. Thermal denaturation experiments represent the increasing melting temperature of DNA (about $4.3^{\circ}C$) due to binding of Fe(2,4-DHSalophen)Cl. These results are consistent with a binding mode dominated by interactions with the groove of ct-DNA.

• Journal of the Korean Chemical Society
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• v.44 no.5
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• pp.410-414
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• 2000

The feasibility of near infrared spectroscopy (NIRS) for the evaluation of the compost pro-duced by composting swine excreta has been investigated. The analytes determined were total nitrogen, total phosphorus, organic matter,total carbon,moisture, Cu, $K_2O$ and $Na_2O$. The ranges of concentration of the cal-ibration samples obtained by the conventional chemical method for each component were 1.30-2.75%, 1.45-4.86%, 7.36-81.5%, 23.0-41.1%, 4.2 the coefficient of variation was 4.38, 5.5, 3.2, 1.5, 10.9, 10.6 and 11.9% for total nitrogen, total phosphorus, organic matter, total carbon, moisture, Cu, $K_2O$ and $Na_2O$,respectively. The overall results showed that NlRS can be used for a non-destructive and rapid determination of the analytes to evaluate the quality of compost samples.

• Polymer(Korea)
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• v.26 no.5
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• pp.589-598
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• 2002

thiathlophene (EDiTT) was synthesized. The yield of the synthesis was about 29%. The monomer was identified by using NMR, IR and UV/Vis spectroscopic methods. Poly (3,4-ethylenedithiathiophene) (PEDiTT) was prepared using this monomer and FeCl$_3$. The deep blue green color of the product was changed into brown color by the reduction with $N_2$H$_4$. This was soluble to common organic solvents. Spectroelectrochemistry was used to characterize the PEDiTT. NMP was the best solvent for PEDiTT. PEDiTT/NMP solution was used for making SAM type thin film of the polymer on gold electrode. Electrochemical and IR spectroscopic methods were used to identify the thin film.

• Journal of the Korean Chemical Society
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• v.48 no.3
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• pp.261-265
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• 2004

We investigated the order of local movement of functional groups (-C(=O)O) in a liquid crystalline (LC) oligomer (12-4) using 2D Raman correlation spectroscopy. The results suggest that the free carbonyl near the ethyl terminal group moved first, followed by the hydrogen-bonded group. The free carbonyl group between the biphenyl groups rarely moved. Interestingly, 2D sample-to-sample correlation spectroscopy (2D STSCS) revealed that some of the carbonyl modes started to move at far below (50$^{\circ}C$) the LC temperature (135$^{\circ}C$), countering conventional beliefs.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2000.06a
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• pp.29-29
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• 2000

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2000.06a
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• pp.46-46
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• 2000

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2002.11a
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• pp.8-24
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• 2002

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2002.11a
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• pp.75-96
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• 2002

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.217-217
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• 2011

플라즈마를 이용하는 식각 및 증착등의 반도체공정에 있어서 최근에는 기판의 크기가 점차 증가하는 추세에 있다. 이러한 대면적 플라즈마 발생장치 내에서 플라즈마 밀도와 라디칼 농도의 공간적인 특성을 이해하는 것에 대한 중요성이 더해지고 있다. 이를 위해 Langmuir probe와 같은 전기적 접근법에 의한 진단방법이나 광학적 접근법에 의한 진단방법에 대한 연구가 이루어 졌다. 전기적 접근법에 의한 플라즈마의 진단방법은 원리가 간단하고 정확도가 높다는 장점이 있지만 진단 장치에 의한 플라즈마의 간섭이 크고 식각가스의 경우 진단이 어렵다는 단점이 있다. 그에 비해 광학적 진단방법은 플라즈마에 간섭이 많지 않은 방법으로 알려져 있고 레이저 형광법(LIF), 원적외선 레이저 흡수 분광법(IR laser Absorption Spectroscopy), 광량측정법(Actinometry)등이 있다. 이 중 레이저 형광법, 원적외선 레이저 흡수 분광법의 경우, 진단장치가 매우 복잡하고 가격이 비싸다는 단점을 가지고 있다. 반면 광량측정법의 경우 다른 광학적 접근법에 의한 진단방법에 비해 원리와 실험장치가 간단하고 공간적인 라디칼 분포의 진단이 쉽다는 점에서 장점을 가지고 있다. Actinometry는 Ar과 같은 불활성 기체를 작은 비율을 넣어서 여기 된 불활성 기체의 파장세기와 여기 된 측정 라디칼의 파장세기의 비교를 통해 상대밀도를 측정하는 방법이다. 이 측정 방법에 Abel's inversion equation을 적용함으로 해서 대면적 M-ICP(Magnetized - Induced Coupled Plasma)에서 식각가스인 $CF_4$플라즈마에서 F 라디칼 농도의 공간적인 분포를 측정하고 분석하였다. 또한 플라즈마의 압력, 소스 전력 값과 기판 전력 값등의 조건의 변화에 따라 F 라디칼 농도의 분포가 어떻게 달라지는지에 대해 측정 분석하여 다루었다.