• Journal of Industrial and Engineering Chemistry
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• 제67권
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• pp.148-155
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• 2018

To get a better understanding of the effect of physicochemical properties and microstructure on $SO_2$ absorption behavior of DESs with different molar ratios of EmimCl and EG (from 2:1 to 1:2), densities (${\rho}$), viscosities (${\eta}$), speeds of sound (u), refractive indices ($n_D$), and thermal decomposition temperatures ($T_d$) of EmimCl-EG DESs were measured and used to obtain the other derived properties, such as thermal expansion coefficient (${\alpha}_p$) and activation energy for viscous flow ($E_{\eta}$). Moreover, FT-IR spectra and in situ variable-temperature NMR spectroscopy were employed to study the microstructures of DESs. Based on physicochemical and spectroscopic properties, the influence of the concentrations of EmimCl on the interactions in DESs was explored to be associated with their $SO_2$ absorption behavior. The results show that the interactions between $Emim^+$ and $Cl^-$ of EmimCl is gradually weakening with increasing the concentration of EG in DESs by forming of hydrogen bond interaction of $O-H{\cdots}Cl^-$, resulting in a decrease of ${\rho}$, ${\eta}$, u, $n_D$, and $T_d$ of DESs, and hindering the charge-transfer interaction of $SO_2$ with $Cl^-$ and deceasing $SO_2$ capture capacity. Moreover, the $SO_2$ absorption capacity of DESs is proportional to their ${\rho}$ and $E_{\eta}$, respectively.

• 한국의학물리학회지:의학물리
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• 제12권1호
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• pp.79-94
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• 2001

생물학적 조직(Biological Tissue)에서 얻어내는 형광(Fluorescence)은 산란(Scattrering), 흡수(Absorption), 그리고 형광체(Fluorophores)가 원인이 되는, 인트린식 형광(Intrinsic Fluorescence)들에 관한 정보를 갖고 있다. 생물학적 조직의 형광스펙트럼은 조직 내에 존재하는 흡수체(Absorber)와 산란물질(Scatters)들의 영향을 받기 때문에 다른 조직의 생화학적인 인트린식 형광을 선형적인 조합으로 해석할 수 없었다. 생물학적 조직 같은 터비드 매질(Turbid Media)로부터 실험적으로 형광을 얻어서 산란과 흡수의 영향을 조사하기 위하여 본 연구소에서 제작한 장치를 소개하고, 넓은 범위의 흡수체와 산란물질의 농도를 갖고 제작한 조직 팬텀(Tissue Phantom)에 대한 형광과 반사(Reflectance) 스펙트럼을 측정하였다. 형광스펙트럼에 존재하는 산란과 흡수의 왜곡(Distortion)을 제거하기 위하여, 반사스펙트럼에 포함된 산란과 흡수 정보를 이용하는 ‘광자 이동 모델(Photon Migration Model)’을 적용하였고, 이러한 조직모델에 대한 인트린식 형광을 얻었다 연구 결과, 모델 값과 실제 인트린식 형광 스펙트럼이 훌륭하게 일치함을 확인하였다. 이런 연구를 하게된 동기는, 인간의 조직이 병들어서 진화하면 조직의 생화학적 구성의 변화가 발생하고 이때 인트린식 형광의 변화가 생기기 때문이다 결론적으로, 조직에 대한 실시간 광학적 생검에서 병든 조직과 정상조직을 단지 형광스펙트럼만으로 구분하는 것은 어렵지만, 인트린식 형광을 이용하면 가능하다.

• Bulletin of the Korean Chemical Society
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• 제27권3호
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• pp.368-372
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• 2006

The cobalt titanate, $CoTiO_3$ nanoparticles have been prepared by calcinations of precursor obtained from a mixture of $TiO_2$ and $Co(OH)_2$ in aqueous cetyltrimethylammonium bromide (CTAB) solution. The nanoparticles were investigated with X-ray powder diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and thermogravimetric/differential thermal analysis (TGA/DTA) to determine the crystallite size and the phase composition. The spectroscopic characterizations of these nanoparticles were also done with UV-Vis spectroscopy and FT-Raman spectroscopy. XRD patterns show that $CoTiO_3$ phase was formed at calcinations temperature above 600 ${^{\circ}C}$. UV-Vis absorption spectra indicate that the $CoTiO_3$ nanoparticles have significant red shift to the visible region (400-700 nm) with $\lambda_{max}$ = 500 nm compared to pure $TiO_2$ powder ($\lambda_{max}$ = 320 nm). The new absorption peaks (absorption at 696, 604, 520, 478,456, 383, 336, 267, 238, 208 $c m ^{-1}$), which were not appeared in FT-Raman spectra of P-25, also confirm the formation of Ti-O-Co bonds at above 600 ${^{\circ}C}$ and just not the mixtures of titanium dioxide with cobalt oxides.

• 한국지하수토양환경학회지:지하수토양환경
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• 제25권2호
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• pp.9-15
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• 2020

This study was conducted to investigate the in situ formation of amorphous Fe oxides as a stabilization technology in As-contaminated soil. After addition of ferric nitrate and the neutralizing agent, most of extractable fractions of As in soil (i.e., SO₄^2- and PO₄^3--extractable As) was converted into As bound to amorphous Fe oxides. In addition, results of solubility bioavailability research consortium (SBRC) test indicated that a significant amount of As in untreated soil changed to a non-bioaccessible form after stabilization. The reason was attributed to the newly formed amorphous Fe oxides in the stabilized soil, which was confirmed by linear combination of fitting (LCF) using X-ray absorption spectroscopy (XAS) analysis. Interestingly, after five months of aging of the stabilized soil, ferrihydrite and schwertmannite newly formed in the soil were transformed to crystalline Fe oxides such as goethite, and further decrease in SBRC extractable fraction of As was observed. The results suggest that co-precipitated As with amorphous Fe oxides can be further immobilized with time, due to the crystallization of amorphous Fe oxides.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.398-398
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• 2013

The electronic properties and the local structure of tantalum oxide thin film with variation of oxygen flow rate ranging from 9.5 to 16 sccm (standard cubic centimeters per minute) have been investigated by X-ray photoelectron spectroscopy (XPS), Reflection Electron Energy Loss Spectroscopy (REELS), and X-ray absorption spectroscopy (XAS). The XPS results show that the Ta4f spectrum for all films consist of the strong spin-orbit doublet $Ta4f_{7/2}$ and $Ta4f_{5/2}$ with splitting of 1.9 eV. The oxygen flow rate of the film results in the appearance of new features in the Ta4f at binding energies of 23.2 eV, 24.4 eV, 25.8, and 27.3 eV, these peaks attribute to $Ta^{1+}$, $Ta^{2+}$, $Ta^{4+}$/$Ta^{2+}$, and $Ta^{5+}$, respectively. Thus, the presence of non-stoichiometric state from tantalum oxide ($TaO_x$) thin films could be generated by the oxygen vacancies. The REELS spectra suggest the decrease of band gap for tantalum oxide thin films with increasing the oxygen flow rate. The absorption coefficient ${\mu}$ and its fine structure were extracted from the fluorescence mode of extended X-ray absorption fine structure (EXAFS) spectra. In addition, bond distances (r), coordination numbers (N) and Debye-Waller factors (${\sigma}^2$) each film were determined by a detailed of EXAFS data analysis. EXAFS spectrapresent both the increase of coordination number of the first Ta-O shell and a considerable reduction of the Ta-O bond distance with the increase of oxygen flow rate.

• 한국진공학회지
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• 제20권4호
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• pp.252-257
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• 2011

본 연구 그룹은 6H-SiC (0001)에서 성장시킨 그라핀 층에 흡착된 퓨란(furan)의 고리 형성과 전자적 성질을 원자 힘 현미경(Atomic Force Microscope : AFM), C K-edge에 대한 Near Edge X-ray Absorption Fine Structure (NEXAFS) 스펙트럼, 핵심부 준위 광전자 분광스펙트럼(Core-level Photoemission Spectroscopy : CLPES)을 이용하여 연구했다. 우리는 그라핀위에 흡착된 퓨란 분자들이 화학적 도핑이 가능한 산소기의 홀 전자쌍을 통하여 그라핀의 특성을 조절할 수 있는 화학적 기능화에 이용될 수 있다는 것을 알아냈다. 또한, 퓨란이 자발적으로 세 가지의 다른 결합 구조들 중 하나로 고리를 형성한다는 것과 그라핀 위에 퓨란에 의해 형성된 고리의 전자적 성질들이 AFM, NEXAFS, CLPES를 이용하여 각각 설명될 수 있다는 것을 보여주었다.

• Journal of the Korean Wood Science and Technology
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• 제28권1호
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• pp.36-41
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• 2000

목재는 2-메타크릴로일옥시에틸 이소시아네이트(MOI)와 $50-60^{\circ}C$에서 촉매존재하에서 매우 쉽게 반응하였다. 적외선 분광분석을 통하여, 목재가 MOI와 우레탄결합($1715cm^{-1}$)를 형성하고 있을 뿐만 아니라, 올레핀구조의 탄소간 이중결합 ($1635cm^{-1}$)이 존재하고 있음이 밝혀졌다. 도입된 메타크릴산기는 다른 비닐모노머와의 그래프트공중합시 반응시점으로 작용할 것이다. 또한 MOI처리목재는, MOI와의 반응에 의해 친수성이던 목재의 표면이 소수화되어 접촉각이 증대되는 결과를 낳았다. X선광전자분광분석(XPS)의 결과, 목재의 표면부위의 대부분은 MOI에 의해 개질되었음을 밝혀졌다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.456-456
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• 2013

We report the modifications in the electronic structureof ZnO thin films induced by swift heavy ion (SHI) irradiated ZnO thin films by using near edge X-ray absorption fine structure (NEXAFS) spectroscopy at O K-edge was performed at BL10D XAS-KIST beamline at Pohang Accelerator Lab (PAL). ZnO films of 250 nm thickness oriented in [200] plane deposited by RF magnetron sputtering using equal $Ar:O_2$ atmosphere and air annealed at $500^{\circ}C$ for 6 hours for stability were irradiated with 120 MeV Au and 100 MeV O beams separately with different doses ranging from $1{\times}10^{11}$ to $5{\times}10^{12}$ ions/$cm^2$. High Resolution X-ray diffraction and NEXAFS analysis indicates significant changes in the electronic structure and the SHI effect is different for Ag and O-beams. The NEXAFS measurements provide direct evidence of O 2p and Zn 3d orbital hybridization. The NEXAFS results will be presented in detail.

• 한국전자통신학회논문지
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• 제16권5호
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• pp.991-1000
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• 2021

비침습식 혈당 검출 기술 중 광학 기법은 생물학적 매체를 통과할 때 빛의 반사와 흡수 및 산란 특성을 이용하는 방법으로 통증이나 측정의 불편함을 감소시키고 감염 위험이 없어 혈당 검출 연구의 주요 흐름이 되고 있다. 이 중 근적외선 분광법은 혈당 분자와 유사한 흡수 기능을 공유하는 단백질과 산의 간섭들로 감지된 신호 분석 시 복잡성이 증가하는 단점이 있다. 본 연구에서는 근적외선의 피부 흡수로 발생할 수 있는 혈당검출 기능저하를 완화시키기 위해 다중 근적외선 대역의 비침습식 센서시스템을 설계하고 제작하였다. 제작한 시스템의 검증을 위해 혈액 조사를 실시하였으며, 혈액 내의 혈당 반응 정도를 스펙트럼 데이터로 수집하고, 데이터와 혈당과의 상관관계 관점에서 정량적으로 본 연구의 성과를 검증하였다.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.2102-2102
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• 2001

Near infrared, diffuse reflectance spectroscopy has shown significant potential for in vitro and in vivo assessment of metabolic status. However, the complexity of living samples can lead to ambiguous results. This presentation will focus on methods that provide controls for scattering and absorption estimation in tissue. For robust estimations, normalization procedures will be shown which can greatly improve interpretability of results. Normalization based on time, location and spectral property will be shown with data from models, tissue phantoms and in vivo measurements. In particular, interpretation of NIR spectra associated with major respiratory constituents will be examined. Measurement of constituents such as hemoglobin, myoglobin, tissue edema, and lactate will be shown. Results suggest that NIR may provide a valuable tool for physiological monitoring in critical care research and practice.