• Advances in materials Research
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• 제13권2호
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• pp.141-151
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• 2024

The aim of this work was to determine the behavior of alloy elements and compounds formed during solidification in the manufacturing process of the CuAgZrCr alloy under an oxidizing environment. Bulk and surface analysis techniques, such as Scanning Electron Microscopy (SEM), X-ray Photoelectron Spectroscopy (XPS), Raman and X-ray diffraction (XRD) were used to characterize the phases obtained in the solidification process. In order to focus the analysis on the on grain boundary interface, partial removal of the matrix phase by acid attack was performed. The compositional differences obtained by SEM-EDX, Raman and XPS on post-manufacturing materials allowed us to conclude that the composition of grain boundaries of the alloy is directly influenced by the oxidizing environment of alloy manufacturing.

• 헤리티지:역사와 과학
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• 제56권4호
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• pp.216-228
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• 2023

본 연구는 대형불화 현장 조사에 비파괴 조사장비 중 하나인 휴대용 라만 분광기를 적용하고 그 결과를 HH-XRF 데이터와 상호 비교하여 장곡사 미륵불 괘불탱에 사용된 채색 재료를 동정하였다. 대형불화에 사용된 채색 재료 분석시, 현장에서 주로 휴대용 현미경과 HH-XRF를 이용한다. 하지만 채색 재료가 경원소로 구성되어 있거나 여러 안료가 중첩 또는 혼합 채색된 경우, 비파괴 분석 데이터만으로는 해석에 한계가 있다. 또한 문화유산이라는 특성상 수습할 수 있는 시료의 양은 제한적이어서 XRD, SEM-EDS 및 라만 분광을 이용한 정밀 분석을 수행하는데 어려움이 있다. 따라서 현장 조사 시 HH-XRF 분석 데이터를 보완할 분석기술이 필요하다. 장곡사 미륵불 괘불탱을 대상으로 백색, 적색, 황색, 녹색, 청색 색상별 채색 재료에 대하여 HH-XRF로 성분을 분석하고 휴대용 라만 분광기를 적용하여 분자구조를 확인하였다. 분석결과, 백색은 연백, 적색은 진사, 석간주, 황색은 등황, 석황, 녹색은 염화동, 청색은 쪽이 사용된 것을 확인할 수 있었다. 휴대용 라만 분광기를 적용함으로써 데이터에 대한 교차검증뿐 아니라 HH-XRF로 확인이 어려웠던 혼합 채색된 안료에 대한 식별과 유기안료에 대한 정보를 획득하는데 도움이 되었다. 또한 대형불화 등 회화문화유산의 비파괴 현장 조사에 휴대용 라만이 다양하게 활용될 수 있을 것으로 판단된다.

• 분석과학
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• 제37권3호
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• pp.174-188
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• 2024

본 연구에서는 토양 및 지하수 중 미세플라스틱(MP) 분석법 표준화를 위해 관련 국내·외 연구동향을 검토하고 매체 별 시료채취 방법, 전처리 방법 및 분석 장치의 종류 등에 관한 대표적인 방법을 리뷰하였다. 토양 시료채취는 시료채취 지점선정, 채취 깊이 및 시료량을 고려하고 있으며 대부분 15 cm 이내(표토) 깊이에서 약 1 kg의 시료를 혼합채취하는 것으로 파악되었다. 지하수 시료채취는 정치방법과 연속흐름방법 중 연속흐름방식이 대표적이고 채취량 300~1,000 L 구간에서 유량 2~6 L/min로 채취하며 현장 여과하였다. 처리 방법은 두 매체에 공통적으로 유기물 분해와 밀도차 분리로 나뉘며 유기물 분해방법인 H₂O₂, 산, 알칼리, 효소 활용 중 H₂O₂가 추천된다. 밀도 분리는 NaCl, ZnCl₂, ZnBr₂ 등의 시약 중 NaCl이 주로 사용되나 분석하고자 하는 MP의 밀도에 따라 시약을 선택적으로 활용할 수 있다. 분석 기기는 비파괴적 분석법인 FTIR, Raman과 파괴 분석법인 Py-GC/MS가 대표적이다. µ-FTIR은 직경 10 ㎛ 이상 Raman은 1 ㎛ 이상의 MP 재질과 개수 분석이 가능하나 전처리를 통해 유기물과 같은 분광분석의 방해요소를 충분히 제거해야 한다. Py-GC/MS는 복잡한 전처리가 필요 없고 특정 재질의 정량분석이 가능하여 지속적으로 연구되어지고 있다.

• Bulletin of the Korean Chemical Society
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• 제30권9호
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• pp.2071-2076
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• 2009

The single-walled carbon nanotubes (SWCNTs) produced by chemical vapor deposition (CVD) were directly fluorinated with fluorine ($F_2$) gas in a temperature range 20 ~ 400 ${^{\circ}C}$. The surface properties and morphology of the SWCNTs were investigated in terms of fluorination temperature. As a result, Raman spectra showed a pair of bands at 1340 and 1590 $cm^{-1}$ peculiar to disordered $sp^2$-carbons. These results indicated that C-F bonds were formed on the rear surfaces of the nanotubes by fluorination, while the external surfaces as well as the layers between the internal and external surfaces retained their $sp^2$-hybridization. XPS analysis exhibited that fluorine atoms were bonded to carbon atoms on internal surfaces (rear surfaces) of the nanotubes and the amount of fluorine attached on the nanotubes was increased with increasing the fluorination temperature. Consequently, the direct fluorination of carbon nanotubes led to functionalization and modification of pristine nanotubes with respect to surface and morphological properties.

• 마이크로전자및패키징학회지
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• 제23권4호
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• pp.7-10
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• 2016

The post cleaning method for clean the shadow mask using in OLED (organic light emitting diode) emitter layer is always reforming. The cleaning solution and analysis method of shadow mask is still lack and not optimized. We use the simple and useful analytical method to determine the quantity and quality of organic and inorganic residue on surface of shadow mask. Finally analyze the cleaning solution using Raman spectroscopy efficiently.

• 한국레이저가공학회지
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• 제5권2호
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• pp.17-22
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• 2002

Characteristics of micro carbon structures fabricated with laser-induced chemical vapor deposition (LCVD) are investigated. An argon ion laser (λ＝514.5nm) and ethylene gas were utilized as the energy source and precursor, respectively. The laser beam was focused onto a graphite substrate to produce carbon deposit through thermal decomposition of the precursor. Average growth rate of a carbon rod increased for increasing laser power and pressure. Micro carbon rods with good surface quality were obtained at near the threshold condition. Micro carbon rods with aspect ratio of about 100 and micro tubular structures were fabricated to demonstrate the possible application of this method to the fabrication of three-dimensional microstructures. Laser Raman spectroscopic analysis of the micro carbon structures revealed that the carbon rods are consisting of amorphous carbon.

• Bulletin of the Korean Chemical Society
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• 제4권1호
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• pp.10-14
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• 1983

Anisotropic rotation of C$_{6}$F$_{6}$ in neat liquid is investigated by the analysis of the ν$_{1}$ and ν$_{15}$ (both C-F stretching) bands of Raman spectrum and diffusion constants for the spinning (D$_{II}$) and tumbling (D$_{⊥}$) motions are obtained by the rotational dffusion theory. The same analysis is also carried out for the ν$_{2}$ and ν$_{16}$ (both C-C stretching) bands and both results are compared with the results obtained for benzene in neat liquid. The results show that the reorientation of C$_{6}$F$_{6}$ is highly anisotropic and the anisotropy is greater for C$_{6}$F$_{6}$ than benzene. This is due to the fact that the spinning rate is about the same but the tumbling rate is sharply reduced for C$_{6}$F$_{6}$.

• Bulletin of the Korean Chemical Society
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• 제21권10호
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• pp.1035-1038
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• 2000

Vibrational properties of dopamine neutral species in powder state have been studied by means of the normal mode analysis based on the force constants obtained from the density functional calculation at B3LYP level and the results of Fourier trans form Raman and infrared spectroscopic measurements. Ab initio calculation at MP2 level shows that the trans conformer of dopamine has higher electronic energy about 1.4 kcal/mol than those of the gauche+ and the gauche-conformers, and two gauche conformers have almost the same energies. Free energies calculated at HF and B3LYP levels show very similar values for three conformers within 0.3 kcal/mol. Empirical force field has been constructed from force constants of three conformers, and refined upon ex-perimental Raman spectrum of dopamine to rigorous values. The major species of dopamine neutral base in the powder state is considered a trans conformer as shown in the crystallographic study of dopamine cationic salt.

• Bulletin of the Korean Chemical Society
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• 제19권12호
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• pp.1363-1368
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• 1998

Mo/γ-Al2O3 catalysts were prepared by impregnation method in various conditions to identify the states of surface Mo species. TPR (Temperature-Programmed Reduction) and Raman spectroscopy were applied to analyze the surface Mo species. TPR analysis revealed that MoO3 was reduced to Mo through MoO2, the intermediate state and the increase of Mo loading enhanced the reducibility of Mo oxide till the formation of monolayer coverage. High temperature calcination induced oxygen defects in MoO3 giving their unstable states for easier reduction. Raman spectroscopy analysis showed that the increase of Mo loading induced the polymeric Mo oxide.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2000년도 추계총회,초청강연,특별강연,연구발표회
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• pp.184.2-184
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• 2000