• Applied Chemistry for Engineering
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• v.25 no.6
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• pp.586-591
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• 2014

In this study, the diarylide compound pigment of high hiding power and vivid color was synthesized successfully by controlling several factors such as pH, coupler solution temperature, kind and addition amount of dispersion precursor, and crystallization temperature in the process of coupling synthesis. The properties of samples were measured by the means of FT-IR, UV-Vis spectroscopy, PSA, zeta potential, and turbiscan. It was found that the highly dispersive sample could be prepared by introducing the dispersive precursor.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.203.2-203.2
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• 2012

IGRINS는 R=40,000의 해상도를 가지고 130K의 저온과 진공 환경에서, 한 번에 H와 K밴드 영역을 동시에 관측할 수 있도록 설계 된 적외선 분광기이다. 이 분광기에는 망원경 초점을 슬릿에 전달하는 IO (Input relay Optics) 모듈과 슬릿을 이미징하는 SVC (Slit Viewing Camera) 모듈 등 2개의 광학모듈이 있다. 광학모듈은 상온 및 저온(130K) 등 온도 변화와 진공 및 비진공 등 환경의 변화를 겪게 되는데, 이 과정에서 변화하는 광학성능을 시뮬레이션과 실험결과로 추적하였다. 시뮬레이션은 ZEMAX 소프트웨어를 사용하였고, 간섭계는 Phasecam 5030을 사용하였으며, IGRINS test dewar 내에 모듈을 설치하여 1,000 class급 청정도 환경에서 WFE를 측정 하였다. Test dewar는 빛이 통과할 수 있는 2개의 윈도우가 있는데, 윈도우는 test dewar 내부와 외부의 진공 및 온도 등 환경 변화에 따라 물리적인 변화가 발생하여 최종 WFE값에 영향을 준다. 본 연구에서는 IGRINS 광학모듈이 진공 및 냉각 상태에서 WFE가 변화하는 양상을 살펴봄으로써, 환경 변화에 따른 광학적 효과를 정량적으로 살펴본 결과를 소개할 것이며, 이 결과는 IGRINS 전체 광학계의 조립 및 정렬 시 환경 변화의 효과를 미리 예측할 수 있도록 하는 자료로 활용될 것이다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.7
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• pp.2713-2718
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• 2010

To improve the CNT's dispersion, we tried to chemically modify the surface of MWNT with the butyllithium and the hexyllithium solution in sonicated reactor. The functionalized-MWNTs were characterized by Fourier transform infrared spectrometer(FT-IR) and Raman spectrophotometer. Also, we investigated the amount of alkyl moiety incorporated into MWNT's surface with Thermal gravimetric analyzer(TGA) and dispersibility in various organic solvents. Finally, we could find organic content was about 5% of the functionalized MWNT and dispersibility was enhanced in some solvents having intermediate solubility parameter.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.148.1-148.1
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• 2013

투어멀린는 $XY_3Z_6(Si_6O_{18})(BO_3)_3$ 화학 방정식을 가진 광물로써 조성에 따라 alkali 투어멀린, calcic 투어멀린, X-site vacant 투어멀린 등으로 불린다. 투어멀린 특성과 화학성분에 따라 종을 구분하는데, 주된 종들은 엘바이트, 리디코타이트, 드라바이트, 우바이트, 숄이 있다. 일반적으로 적색 투어멀린의 발색 원인은 Mn, Fe 그리고 Cu의 함량에 따라 색상의 차이를 나타낸다. 본 연구에서 우리는 10MeV 에너지와 $1{\times}10^{17}cm^2$ 조건에서 전자빔을 수행 한 후 투어멀린의 컬러 변화를 관찰하였다. 자외선-가시광선 분광분석결과 모든 시료는 전자빔 조사 후 530 nm의 $Mn^{3+}$부근의 흡수 peak들이 증가하는 것이 관찰되었다. 이는 $Mn^{2+}$에서 $Mn^{3+}$ 이동 때문이여, $Mn^{3+}$는 Y-site에서 O(1)H-O(3)H 축에 따라 Jann-taller 변형으로 안정된 구조를 가지게 된다. 따라서 전자빔 조사 후 적색으로 변하게 되는 것이다. 또한 전자빔 조사 후 컬러가 모두 변했지만 상온에 뒀을 때 변화 된 컬러가 원래의 색으로 되돌아가는 향상을 보였다. 이는 전자빔 조사 후 전자가 튕겨져 나가서 불안정한 상태로 존재하고 있다가 상온의 열에 의한 에너지에 통해 다시 안정된 상태로 되돌아오는 결과로 볼 수 있다. 또한 우리는 WD-XRF를 통해 미량의 Mn 원소함량 차이에 따라 전자빔 조사 시 컬러 변화에 미치는 영향에 대해 확인할 수 있었다. 그리고 적외선 분광분석에서는 4,300-4,600 $cm^{-1}$사이에 특징적인 밴드들이 관찰되었다.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.4
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• pp.36-42
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• 2021

In this study, the impregnation of Lyocell fabrics was performed using phosphoric acid, ammonium phosphate, diammonium hydrogen, triammonium phosphate as phosphorus flame retardant, to fabricate continuous graphite fabrics using lyocell fiber. The physical and chemical structure changes were investigated by thermogravimetric, Fourier-transform infrared spectroscopy, C-nuclear magnetic resonance, X-ray diffraction, and weight analyses, By analyzing the thermal behavior of phosphorus flame retardant, conditions for the temperature, gas, and residual time of the pyrolysis process were set. Graphite fabrics with a tensile strength of 1,007.19±11.47 N/5 cm and yield of 25.3% were fabricated using continuous pyrolysis, carbonization and graphitization process.

• Analytical Science and Technology
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• v.15 no.4
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• pp.373-380
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• 2002

Humic and fulvic acids present in soil of different depth were extracted and their characteristics were analyzed as a basic study to evaluate the effect of humic substances on the behaviour of radioactive elements deposited on soil. Molecular size distribution of the humic and fulvic acids was measured by stirred cell ultrafiltration technique and the structural informations were obtained from their UV-Vis., IR and synchronous fluorescence (SyF) spectral analysis. Main molecular size ranges of the soil 1) humic and fulvic acids were 30~100 kDa (46~56%) and 10~30 kDa (33~43%) respectively, and their overall molecular sizes were found to became smaller with increasing the soil depth. Absorptivities measured at 280 nm in the UV-Visible spectra of humic acids were 1.4~1.5 times higher than those of fulvic acids, and increased with increasing the soil depth. SyF spectral data showed two distinct peak components having maximum peak positions of 428 nm (type I) and 498 nm (type II) for the soil humic and fulvic acids. From the analysis of the peak components, it was found that humic molecules are mainly made up of aromatic compounds corresponding to longer wavelength (type II), and the molecular components increased with increasing the soil depth. Analysis of IR spectral data indicated that the humic molecules contain a higher relative concentration of carboxylic groups than those of fulvic molecules, and the carboxylic group contents are seen to increase as the soil depth increase.

• Journal of The Korean Society of Grassland and Forage Science
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• v.29 no.1
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• pp.31-36
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• 2009

This study was conducted to find out an alternative way of rapid and accurate analysis of forage quality. Near reflectance infrared spectroscopy (NIRS) was used to evaluate the possibility of forage analysis and collect 258 samples such as barley for whole crop silage, forage corn and sudangrass from 2002 to 2007. The samples were analyzed for CP (crude protein), CF (crude fiber), ADF (acid detergent fiber), NDF (neutral detergent fiber) and IVTD (in vitro true digestibility), and also scanned using NIRSystem with wavelength from $400{\sim}2,400nm$. Multiple linear regression was used with wet analysis data for developing the calibration model and validate unknown samples. The important index In this experiment was SEC and SEP $r^2$ for CF, CP, NDF, ADF and IVTD in calibration set were 0.70, 0.86, 0.94, 0.94 and 0.89, also 0.47, 0.39, 0.89, 0.90 and 0.61 in validation sample, respectively. The results of this experiment indicates that NIRS was reliable analytical method to assess forage quality, specially in CF, ADF and IVTD, sample should be included for respective forage samples to get accurate result. More robust calibrations can be made to cover every forage samples if added representative sample set.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.7
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• pp.626-634
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• 2015

In the present study, numerical predictions of infrared spectra for $CO_2$ molecule were conducted. Absorption coefficients of $CO_2$ which are required for simulating the spectra, were calculated by using a line-by-line method and by adopting spectroscopic parameters from the radiation databases, HITEMP2010 and CDSD-4000. Simulations were made in the 2.7, 4.3, and $15{\mu}m$ band regions, and the results were compared with the measurements of other researchers. It was found that the calculated results are well matched with the various measurements. However, in the $4.3{\mu}m$ band region, the CDSD-4000 based calculation yields a better fit to the measurement than the HITEMP2010 based calculation does.

• Journal of the Korean Chemical Society
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• v.31 no.1
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• pp.3-13
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• 1987

Infrared absorption spectra of alkyl alcohols in the OH stretching region were obtained from varying the concentrations of alcohols in $CCl_4$. The OH stretching bands were broadened and shifted to lower frequencies due to the hydrogen-bond formation. Three bands were obtained from the breakdown of these bands by the simplex method. Each band was assigned to various types of hydrogen-bonded OH groups. The electronic structures and interaction energies of dimeric and trimeric alcohols were calculated by semi-empirical MO(CNDO/2, INDO) methods. These results were in good agreement with those of deconvoluted ir spectra. The EDA(electron donor-acceptor) effect of alkyl group on hydrogen-bond formation was in the decreasing order of butyl > propyl > ethyl > methyl group. On the other hand, the experimental results were in the order : propyl > ethyl > butyl > methyl group. This seemed to be ascribed to the bulkiness of butyl alcohol.

• Journal of the Mineralogical Society of Korea
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• v.28 no.2
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• pp.83-93
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• 2015

This study investigated genetic, mineralogical and spectral characteristics of oil shale and coal samples in Dundgobi area, Mongolia. Based the Rock/Eval and Total organic carbon (TOC) analysis, kerogen type, hydrogen quantity, thermal maturity and depositional environment were confirmed. Moreover, the mineral composition of oil shale and coal samples were analyzed by XRD and spectroscopy. The result of Rock Eval/TOC analysis revealed that the samples of Eedemt deposit are immature to mature source rocks with sufficient hydrocarbon potential, and the kerogen types were classified as Type I, Type II and Type III kerogen. On the other hand, the samples from Shine Us Khudag deposit were mature with good to very good hydrocarbon potential rocks where kengen types are defined as Type I, Type II/III and Type III kerogen. According to the carbon and sulfur contents, the depositional environment of the both sites were defined as a freshwater depositional environment. The XRD analysis revealed that the mineral composition of oil shale and coal samples were quartz, calcite, dolomite, illite, kaolinite, montmorillonite, anorthoclase, albite, microcline, orthoclase and analcime. The absorption features of oil shale samples were at 1412 nm and 1907 nm by clay minerals and water, 2206 nm by clay minerals of kaolinite and montmorillonite and 2306 nm by dolomite. It is considered that spectral characteristics on organic matter content test must be tested for oil shale exploration using remote sensing techniques.