• Title/Summary/Keyword: 엑스선 회절분석

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Preparation and Characteristics of Te Fine Particles Doped SiO2 Glass Thin Films by Sol-gel Method (졸-겔법에 의한 Te 미립자 분산 SiO2 유리 박막의 제조와 특성)

  • Mun, Chong-Soo;Kang, Bong-Sang
    • Journal of the Korean Ceramic Society
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    • v.41 no.1
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    • pp.24-29
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    • 2004
  • Nanocomposite of Te doped $SiO_2$ films was prepared for the new functional materials like non-linear optic materials, selective absorption and transmission films. The effects of particle size and morphology with different hydrolysis conditions on the properties were examined with TGA/DTA. XRD. UV-spectrometer, SPM, SEM and EDS. It was found that Te/$SiO_2$ films showed high absorption peak at 550nm visible region by plasma resonance of Te fine particles. The Rm surface roughness of the films was about 2.5 nm and the size of Te particles was 5~10nm.

Olivine Synthesis Using Stainless Steel Tube (스테인리스강관을 이용한 감람석 합성)

  • Gi Young Jeong
    • Korean Journal of Mineralogy and Petrology
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    • v.36 no.4
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    • pp.337-343
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    • 2023
  • Olivine is a complete solid solution of fayalite and forsterite that is abundant in Earth and extraterrestrial materials such as rocky planets, meteorites, asteroids, and interplanetary dust. Due to the wide range of olivine compositions, diverse olivine standards are required for quantitative mineralogical analysis of olivine-bearing materials. Olivine standards were synthesized using an electric furnace and stainless steel tubes at temperatures ranging from 1000~1100 ℃. Overall, olivine was synthesized covering the full range of composition, with some synthetic impurities and unreacted material. The synthesized olivine showed a linear increase in the unit cell dimension in proportion to the molar ratio of fayalite in the starting materials, and the diffraction intensity was consistent with that of natural olivine. However, iron-rich synthetic olivine samples tend to have a higher content of impurity, suggesting that not all synthetic olivine can be used as a standard material yet, and improvements in the synthesis process, such as using high purity starting materials and control of reaction time and temperature, are required.

Study on the Composition and Crystallization of TiNi Thin Films Fabricated by Pulsed Laser Deposition in Ambient Ar Gas (Ar가스 분위기에서 PLD방법으로 제작된 TiNi박막의 조성 및 결정성에 관한 연구)

  • Cha, J.O.;Shin, C.H.;Yeo, S.J.;Ahn, J.S.;Nam, T.H.
    • Journal of the Korean Vacuum Society
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    • v.16 no.2
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    • pp.116-121
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    • 2007
  • TiNi shape memory alloy(SMA) was fabricated by PLD(plused laser deposition) using equiatomic TiNi target. Composition and crystallization of TiNi thin films which were fabricated in ambient Ar gas(200m Torr)and vacuum($5{\times}10^{-6}\;Torr$) were investigated. Composition of TiNi thin films was characterized by energy-dispersive X-ray spectrometry (EDXS) and crystallization was confirmed by X-ray diffraction (XRD). The composition of films depends on the distance between target and substrate but does not sensitively depend on the substrate temperature. It is found that the composition of films can be easily controlled when substrate is placed inside plume in ambient Ar gas. It is also found that the in situ crystallization temperature ($ca.\;400^{\circ}C$) in ambient Ar gas is lowered in comparison with that of TiNi film prepared under vacuum. The low crystallization temperature in ambient Ar gas makes it possible to prepare the crystalline TiNi thin film without contamination.

Predicting Unknown Composition of a Mixture Using Independent Component Analysis (독립성분분석을 이용한 혼합물의 미지성분비율 예측)

  • Lee Hye-Seon;Song Jae-Kee;Park Hae-Sang;Jun Chi-Hyuck
    • The Korean Journal of Applied Statistics
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    • v.19 no.1
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    • pp.135-148
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    • 2006
  • Independent component analysis (ICA) is a statistical method for transforming an observed high-dimensional multivariate data into statistically independent components. ICA has been applied increasingly in wide fields of spectrum application since ICA is able to extract unknown components of a mixture from spectra. We focus on application of ICA for separating independent sources and predicting each composition using extracted components. The theory of ICA is introduced and an application to a metal surface spectra data will be described, where subsequent analysis using non-negative least square method is performed to predict composition ratio of each sample. Furthermore, some simulation experiments are performed to demonstrate the performance of the proposed approach.

Influences of the Composition on Spectroscopic Characteristics of AlxGa1-xN Thin Films (AlxGa1-xN 박막의 조성이 분광학적 특성에 미치는 영향)

  • Kim, Dae Jung;Kim, Bong Jin;Kim, Duk Hyeon;Lee, Jong Won
    • New Physics: Sae Mulli
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    • v.68 no.12
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    • pp.1281-1287
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    • 2018
  • In this study, $Al_xGa_{1-x}N$ films were grown on (0001) sapphire substrates by using metal-organic chemical vapor deposition (MOCVD). The crystallinity of the grown films was examined with X-ray diffraction (XRD) patterns. The surfaces and the chemical properties of the $Al_xGa_{1-x}N$ films were investigated using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS), respectively. The optical properties of the $Al_xGa_{1-x}N$ film were studied in a wide photon energy range between 2.0 ~ 8.7 eV by using spectroscopic ellipsometry (SE) at room temperature. The data obtained by using SE were analyzed to find the critical points of the pseudodielectric function spectra, $<{\varepsilon}(E)>=<{\varepsilon}_1(E)>+i<{\varepsilon}_2(E)>$. In addition, the second derivative spectra, $d^2<{\varepsilon}(E)>/dE^2$, of the pseudodielectric function for the $Al_xGa_{1-x}N$ films were numerically calculated to determine the critical points (CPs), such as the $E_0$, $E_1$, and $E_2$ structure. For the four samples (x = 0.18, 0.21, 0.25, 0.29) between a composition of x = 0.18 and x = 0.29, changes in the critical points (blue-shifts) with increasing Al composition at 300 K for the $Al_xGa_{1-x}N$ film were observed via ellipsometric measurements for the first time.

Preparation of Polypropylene/Clay Nanocomposites Using Aminosilane Treated Clay (아미노실란 개질 클레이를 사용한 폴리프로필렌 클레이 나노복합재료)

  • Hong Chae-Hwan;Bae Jin-Woo;Lee Yong-Bum;Lee Choon-Soo;Jho Jae-Young;Nam Byeong-Uk
    • Polymer(Korea)
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    • v.30 no.4
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    • pp.318-325
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    • 2006
  • Polypropylene-clay nanocomposites were studied by the modification of clay with amino silanes to introduce covalent bonds in nanocomposites, and prepared by melt-compounding with polypropylene, clay modified with amino silanes and maleic anhydride grafted polypropylene. The . .structure and surface properties of modified clay were determined by x-ray diffraction, infrared spectrum, and solid-state $^{29}Si$ nuclear magnetic resonance spectrum. The modification of clay with aminosilanes led to the increase of the silicate interlayers to about $19.8{\AA}$, the weakening effects of hydroxy group at $3650cm^{-1}$ and the signal of amine groups at -69 ppm proved that the modification had taken place.

Preparation of Spherical TiO2 Nanoparticles Using Amphiphilic PCZ-r-PEG Random Copolymer Template Membrane (양친성 PCZ-r-PEG 랜덤 공중합체 분리막을 이용한 구형 이산화티타늄 나노입자의 제조)

  • Lee, Jae Hun;Patel, Rajkumar
    • Membrane Journal
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    • v.29 no.3
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    • pp.183-189
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    • 2019
  • Amphiphilic PCZ-r-PEG random copolymer assisted solvothermal process is used to prepare mesoporous $TiO_2$ microspheres generated from nanoparticles by self-assembly method. Synthesized PCZ-r-PEG is characterized by Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), gel permeation chromatography (GPC) and transmission electron microscopy (TEM). The mesoporous $TiO_2$ are prepared by PCZ-r-PEG, glucose, water in tertrahydrofuran solution at $150^{\circ}C$ for 12 h and the $TiO_2$ microspheres are calcined at $550^{\circ}C$ for 30 min to further crystallize and organic residue are removed. Morphology and crystallization phase is characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) respectively. The mesoporous $TiO_2$ crystallized in pure anatase phase with diameter of $300{\pm}20nm$.

The Effect of Crystallinity on the Photoluminescence of TiO2 Nanoparticles (결정성에 따른 TiO2 나노입자의 포토루미네선스 영향)

  • Han, Wooje;Park, Hyung-Ho
    • Journal of the Microelectronics and Packaging Society
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    • v.26 no.1
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    • pp.23-28
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    • 2019
  • The Titanium oxide ($TiO_2$) is an attractive ceramic material which shows non-toxic, high refractive index, catalytic activity and biocompatibility, and can be fabricated at a low cost due to its high chemical stability and large anisotropy. $TiO_2$ nanoparticles have been prepared by sol-gel method. The pH of solution can affect the $TiO_2$ crystallinity during the formation of nanoparticles. The prepared nanoparticles were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, photoluminescence spectroscopy in order to investigate their structural and photoluminescence properties. Through these analysis, the size of $TiO_2$ nanoparticles were found to be smaller than 5 nm. As the crystallinity of the nanoparticles increased, the emission of PL in the 550 nm region increased. Therefore, luminescence characteristics can be improved by controlling the crystallinity of the $TiO_2$ nanoparticles.

Effect of Guest Molecules on Structure and Properties of Polymer/beta-Cyclodextrin Inclusion Compound Hybrid Films (고분자/베타-사이클로덱스트린 포접 화합물로 이루어진 고분자 혼성체 필름의 물성 및 구조에 미치는 게스트 분자의 영향)

  • Bae, Joonwon
    • Applied Chemistry for Engineering
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    • v.32 no.5
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    • pp.504-508
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    • 2021
  • In this study, the effect of molecular features of guest molecules on the structure, property, and formation of poly(vinyl alcohol) (PVA)/beta-cyclodextrin (bCD) inclusion compound hybrid films was investigated using three types of guest molecules such as hydroquinone (HQ), arbutin (AB), and tranexamic acid (TA). First, the successful formation of inclusion compounds between bCD and the guest molecules, and polymer/inclusion compound hybrid were proved using Raman spectroscopy. The effect of bCD-based inclusion compounds on the structure and property of PVA matrix composites containing inclusion compounds was also studied using X-ray diffraction (XRD) and thermal analyses such as differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). It was notable that the effect of TA to the crystalline structure of the PVA was significantly different from that of using other guest molecules including HQ and AB. It was also supported by a simple molecular simulation result. This article will be a good example for demonstrating the effect of molecular characteristics on the inclusion compound formation in polymer films, which can provide important information for relevant future research.

Spectroscopic Identifications and Phase Equilibria of THF + 3-OH THF + CH4 Clathrate Hydrates (삼성분계 THF + 3-OH THF + CH4 크러스레이트 하이드레이트의 상평형 거동 해석 및 분광학적 분석)

  • Kim, Heejoong;Ahn, Yun-Ho;Moon, Seokyoon;Hong, Sujin;Park, Youngjune
    • Korean Chemical Engineering Research
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    • v.55 no.3
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    • pp.353-357
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    • 2017
  • In this study, the inclusion phenomena of tetrahydrofuran + 3-hydroxytetrahydrofuran + $CH_4$ clathrate hydrates were explored via thermodynamic and spectroscopic approaches. The phase equilibria of the double hydrates - THF + $CH_4$ and 3-OH THF + $CH_4$ clathrate hydrates - were determined by pressure-temperature trace during hydrate formation and dissociation, and the result revealed that the equilibrium pressures were shifted to lower pressure region compared to pure $CH_4$ hydrate. The powder X-ray diffraction patterns revealed that the double hydrates of THF + 3-OH THF formed structure II type clathrate hydrates with $CH_4$. The dispersive Raman spectra of the double clathrate hydrates also exhibited that $CH_4$ can be trapped in both $5^{12}6^4$ and $5^{12}$ cages whereas THF and 3-OH THF were encaged in $5^{12}6^4$ cage.