• 천문학회보
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• 제43권1호
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• pp.67.1-67.1
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• 2018

We present high-resolution near infrared (IR) spectra of two candidate planetary nebulae (PNe) that were serendipitously found toward the Galactic center (GC). Our spectra obtained using GNIRS on Gemini North reveal strong Br ♑ and He I recombination lines. In one of the targets, we confidently detect Pa ♌ emission. Based on Br ♑ and Pa ♌ lines, we estimate a foreground reddening to be Av=27 mag, which confidently puts this object at the GC distance. Along with the presence of highly excited emission lines such as [S IV], [Ne III], [Ne V], and [O IV] detected in the mid-IR spectra from the Spitzer Space Telescope, and the extended emission in the Pa ♋ narrow-band image from the Hubble Space Telescope, this makes it the first spectroscopically confirmed PN in the GC.

• 분석과학
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• 제20권2호
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• pp.124-130
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• 2007

In this study, we present the preparation and characterization of oxidized fullerene and fullerene dimer [$C_{120}$]. From the XRD data, other weak peaks with pristine fullerene [$C_{60}$] peaks were observed in the X-ray diffraction patterns for fullerene dimer [$C_{120}$]. SEM micrographs for the fullerene dimer [$C_{120}$] indicated that practically all the surface state was shown the drastic morphology changes and its outer surface is clearly visible and resulted in clogging and frost-like formation. From the MALDI-TOF mass spectra, the differences in the spectra recorded on two kinds of fullerene are due to the oxidation including chemical bonding and bridging between the $C_{60}$ molecules. We also obtained additional information from FT-IR spectra on functional component on the chemically modified surface of oxidized fullerene and fullerene dimer [$C_{120}$].

• Bulletin of the Korean Chemical Society
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• 제23권12호
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• pp.1729-1732
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• 2002

The LB71350,(3S, 4R)-Epoxy-(5S)-[[N-(1-methylethoxy)carbonyl]-3-(methylsulfonyl)-L-valinyl]amino]-N-[2-methyl-(1R)-[(phenyl)carbonylpropyl-6-phenylhexanamide, is a novel HIV protease inhibitor. Its equilibrium solubility at room temperature was less than $40{\mu}g/mL.$ It was speculated that the low aqueous solubility might be due to the high crystalline lattice energy resulting from intermolecular hydrogen bonds. The present study was carried out to learn the solid-state characteristics of LB71350 using analytical methods such as NMR, FT-IR and XRD. $^{13}C$ Solid-state NMR, solution NMR, and FT-IR spectra of the various solid forms of LB71350 were used to identify the conformation and structure of the solid forms. The chemical shifts of $^{13}C$ solid-state NMR spectra suggest that the crystalline form might have 3 intermolecular hydrogen bondings between monomers.

• 산업기술연구
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• 제27권B호
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• pp.109-114
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• 2007

Humic substances generally comprise 30-50% of the dissolved organic carbon in water. They can affect water quality adversely in several ways and they are important from a water treatment perspective due to their role as precursors for the formation of chlorination by-products such as trihalomethanes. The objectives of this research are to investigate the characteristics of organic matter using raw water of Chuncheon area, to isolate the humic substance fractions from natural water samples, and characterize the extracted humic substances. Humic substances were fractionated according to "isolation of IHSS aquatic humic and fulvic acids" using XAD resin adsorption technique. Characteristics of humic substances were analyzed through DOC, $UV_{254}$, $SUVA_{254}$, FT-IR spectra, fluorescence analysis.

• Bulletin of the Korean Chemical Society
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• 제33권10호
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• pp.3391-3396
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• 2012

Two-dimensional infrared (2D-IR) spectroscopy can probe the fast structural evolution of molecules under thermal equilibrium. Vibrational frequency fluctuation caused by structural evolution produced the time-dependent line shape change in 2D-IR spectrum. A variety of methods has been used to connect the evolution of 2D-IR spectrum with Frequency-Frequency Correlation Function (FFCF), which connects the experimental observables to a molecular level description. Here, a new method to extract FFCF from 2D-IR spectra is described. The experimental observable is the time-dependent frequency shift of maximum peak position in the slice spectrum of 2D-IR, which is taken along the excitation frequency axis. The direct relation between the 2D-IR peak shift and FFCF is proved analytically. Observing the 2D-IR peak shift does not need the full 2D-IR spectrum which covers 0-1 and 1-2 bands. Thus data collection time to determine FFCF can be reduced significantly, which helps the detection of transient species.

• 분석과학
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• 제11권6호
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• pp.469-473
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• 1998

자동차용 휘발유 제조사의 확인 또는 판별은 석유류의 정상적인 유통관리 및 오염사고시 오염원의 추적을 위해 필요하다. 일반적으로 휘발유의 화학적 조성은 가스크로마토그래피(GC)로 분석이 가능하며, 제품별로 얻어진 크로마토그램의 차이로부터 각 제품을 구분할 수 있으나 제조기준의 세분화로 휘발유의 조성이 유사해져 GC분석에 의한 판별이 더욱 어렵게 되었다. 본 연구에서는 보다 신속하고 정확하게 휘발유 제품을 판별하기 위하여, 분산제의 적외선 분광스펙트라를 비교하여 제조사(A, B, C, D, E사로 구분)를 구분하는 방법을 도식화하였다. IR spectra는 휘발유를 검시험기(gum tester)로 증발시키고, 잔여물을 n-pentane으로 녹여 ATR(Attenuated Total Reflectance) cell로 옮기고 다시 용매를 증발시킨 후에 얻었다. 'A', 'B', 및 'C'정유사에서 사용하는 첨가제들은 에테르(ether)의 C-O 신축진동에 의한 넓고 강한 피크가 $1,096cm^{-1}$에서 나타나 'D'와 'E'정유사의 첨가제들과 뚜렷하게 구별이 가능하였고, 또 다른 특징적인 피크들로써 각 정유사 제품의 구분이 모두 가능하였다.

• Journal of the Korean Wood Science and Technology
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• 제16권4호
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• pp.3-9
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• 1988

Infrared (IR) spectroscopic techniques for the analysis of wood samples and the absorbance spectra of solid woods were presented. KBr pellets were prepared by throughly mixing approximately 300 mg of dried KBr and 1 mg of finely milled wood powder extracted with ethanol-cyclohexane previously. This mixture was made into a transparent disc by means of a pellet-making die (10 ton/$cm^2$ for 10 min). This IR techniques were applied for the analysis of archaeological wood samples. The most notable difference in the IR spectra between the recent and the archaeological waterlogged woods is that the absorption band centered at $1,730cm^{-1}$ was significantly diminished in the waterlogged ones. Total loss of absorption in $1,730cm^{-1}$ might be mainly due to the result of hemicellulose degradation. Another feature indicated by IR spectral comparision are that the degraded waterlogged wood samples showed 1) the increased intensity of the 1,600, 1,500 and $1,270cm^{-1}$ due to the residual lignin and the increased intensity at 1,470 and $1,425cm^{-1}$ due to the degradation of hemicellulose and 2) to the emergence of single band around $1,050cm^{-1}$ instead of three bands at 1,110, 1,060 and $1,040cm^{-1}$ in recent wood due to the degradation of cellulose crystalline. It was revealed from the IR examinations that the first change of wood in the waterlogged situation was the lysis of hemicellulose and the second the lysis of cellulose. It was also suggested that IR spectroscopy could serve a fast method for the investigation on the chemical characteristics of archaeological wood samples.

• 보존과학회지
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• 제33권5호
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• pp.345-354
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• 2017

전남 진도군 소재 사찰의 보수 공사 중 벽화가 발견되어 제작기법 파악을 위해 교착제로 사용된 물질을 확인하고자 하였다. 이에 해당 벽화 시편에 대해 열분해/GC/MS와 IR 분석을 실시하였으며, 열분해/GC/MS분석은 직접 열분해와 온라인 메틸화법을 도입하였다. IR 분석에서 아교, 옻, 황칠 등 전통 교착제와 초산아크릴계 수지의 스펙트럼을 벽화시편과 비교했을 때 유사하지 않았으며, 건성유인 아마인유와 비교했을 때도 유사도가 낮았다. 벽화시편의 열분해/GC/MS 분석 결과를 옻, 황칠, 아교, 초산아크릴수지와 비교했을 때 이들 물질이 아닌 것으로 나타났다. 한편, 벽화시편에서 팔미트산, 옥타데칸산, nonanedioic acid, 옥타데센산 등 건성유에 특징적인 물질이 검출되었고, 경화 건성유와 유사한 열분해/GC/MS 크로마토그램이 관찰되었다. 따라서, 벽화는 건성유를 교착제로 사용하여 제작된 것으로 판단되었다.

• 대한화학회지
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• 제52권4호
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• pp.369-379
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• 2008

• 대한화학회지
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• 제56권3호
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• pp.357-362
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• 2012

5-Nonylsalicylaldoxime and salicylaldehyde are two derivatives of phenolic compounds which are very applicable materials in industries. Formerly the formylation of phenolic derivatives were carried out by Rimer-Tiemann method. In this work both of these two materials were synthesized by magnesium meditated formylation technique and their structural characterizations were compared by instrumental analysis technique. In order to achieve a selectively orthoformylated product, the hydroxyl group of nonylphenol (or phenol) was first modified by magnesium methoxide. The nonylphenol magnesium salt was then formylated by paraformaldehyde. The oximation reaction was finally applied to the prepared nonylsalicylaldehyde magnesium salt by liquid extracting via water and acid washing and other extractions. The solvent was finally removed by evaporation under reduced pressure. Some instrumental analysis such as $^1H$-NMR, GC/MS and FT-IR spectra were taken on the product in order to interpret the reaction characterization quantitatively and qualitatively. The formaldehyde and oxime functional groups of two compounds were investigated through $^1H$-NMR and FT-IR spectra and were compared. The yield of methoxilation was very good and the yields of formylation and oximation reactions were about 90%and 85% respectively. The orthoselectivity of formylation reaction were evaluated by comparing of the relevant spectra. The GC/MS spectra also confirmed the obtained results.