졸-겔법을 이용한 투과성 TiO₂ 분말 및 박막의 특성 연구

정미원,이지영,손현진,Jung, Mie-Won,Lee, Zee-Young,Son, Hyun-Jin 한국세라믹학회 2002 한국세라믹학회지 Vol.39 No.3

Titanium(IV) isopropoxide에 킬레이팅 리간드로 Acetylacetone(Acac), Ethyl-acetoacetate(Etac) 그리고, Ethanolamine을 첨가시켜 변형된 티타늄 알콕사이드를 합성한 후 졸-겔 방법으로 투과성 티타늄 산화물 박막을 제조하였다. 박막 제조 조건이 최적의 상태일 때는 티타니아 졸 용액의 농도가 3wt% 이하이고, 리간드로는 Acetyl acetone(Acac)를 선택하고, pH가 2.5로 조절하였을 때였다. 순수한 티타늄 산화물 박막보다는 리간드가 치환된 박막들의 굴절률이 더 높았고 가시광선 영역에서 80% 이상의 투과율을 나타냄을 알 수 있었다. 티타니아 졸 상태에서는 입자 크기가 나노 크기를 나타냈으며 분말로 소성 후 마이크론 크기로 증가함을 알 수 있었다. 티타늄 박막들은 400$^{\circ}$C에서 무정형에서 anatase로 상전이가 일어나고 700$^{\circ}C$에서는 rutile로 변화됨을 XRD로 관찰하였다. 박막의 결정형태와 모양 및 크기도 SEM과 XRD로 측정하였다. 또한 분말의 물성 및 구조를 SEM, XRD, TGA 그리고 DSC로 알아보았고, 박막의 광학적 특성에 대해서는 ellipsometer로 굴절률과 막두께를 측정하여 비교하여 보았다. Transparent $TiO_2$ thin films prepared by sol-gel process using the modification of titanium(IV) alkoxide showed improved thermal stability and high refraction index. Compared to the pure $TiO_2$ film, the modified $TiO_2$ films show the increased index of refraction under proper condition at pH 2.5. Transparency of these $TiO_2$ thin films were more than 80% in the visible region. It has been demonstrated that the reaction occurs in the amorphous phase: an exchange of phase results in anatase before and after 400$^{\circ}C$, in rutile over 700$^{\circ}$C form the XRD results. The particle sizes, shapes and structures of these nanoclusters in the $TiO_2$ films have been identified through a SEM and XRD. The physical properties and structures of their powders have also been studied through a SEM, XRD, TGA and DSC. The thickness and index of refraction have been determined by the analysis of ellipsometric spectra.

수소 가압형 기계적 합금화법에 의한 MgHx-V2O5 복합재료의 수소화 특성

정미원,박지희,조경원,김경일,최재하,김상헌,홍태환 한국수소및신에너지학회 2010 한국수소 및 신에너지학회논문집 Vol.21 No.1

Mg and Ma-based alloys are promising hydrogen storage materials for renewable clean energy applications. It has high hydrogen storage capacity (7.6wt.%), lightweight and low economical materials. However, commercial applications of the Mg hydride are currently hindered by its high operating temperature, and very slow reaction kinetics. In this work, we are aimed at studying the hydrogenation properties of the MgHx-V2O5 composite prepared by hydrogen induced mechanical alloying. The absorption capacity of the sample is found to be about 4.7wt.% at 623K under 3 MPa H2 pressure. The absorption characteristics observed have been compared with prepared MgHx.

Quinacridone을 첨가시킨 SnO₂가 도핑된 TiO₂ 분말의 광촉매 특성

정미원,곽윤정,Jung, Miewon,Kwak, Yunjung 한국공업화학회 2007 공업화학 Vol.18 No.6

$SnO_2$-doped $TiO_2$ powder was obtained from tin (IV) bis(acetylacetonate) dichloride and titanium diisopropoxide bis(acetylacetonate) with quinacridone as the dye sensitizer molecule. The structural changes of the reaction mixture were monitored by fourier transform infrared (FT-IR) spectroscopy. The morphology and microstructure of gel powder were studied by field-emission scanning electron microscopy (FE-SEM) and X-ray diffractometry (XRD). The photocatalytic activity of these powders with the anatase structure was investigated by using indigo carmine solution as a test dye

고분자 첨가법에 의해 SnO₂가 도핑된 TiO₂ 분말의 합성 및 광촉매 특성

정미원,곽윤정,Jung, Miewon,Kwak, Yunjung 한국공업화학회 2006 공업화학 Vol.17 No.5

$SnO_{2}$-doped anatase type $TiO_{2}$ powder was prepared by the polymerization complex route from tin(IV) bis (acetylacetonate) dichloride, titanium diisopropoxide bis (acetylacetonate) and polyethylene glycol (PEG) as a complexing agent. The structural changes of reaction mixture were monitored by fourier transform infarared (FT-IR) spectroscopy. The microstructure and morphology of gel powder were studied by field-emission scanning electron microscopy (FE-SEM) and X-ray diffractometry (XRD). The photocatalytic activity of these powders with the anatase structure was investigated by using indigo carmine solution.

Titanium(IV) isoproxide 유도체의 합성 및 특성연구

정미원,Jung, Mie-Won 한국분석과학회 1999 분석과학 Vol.12 No.6

The systematic modification of titanium(IV) isopropoxide with acetic acid as a organic additive was done and identifided by FT-IR, $^1H$, $^{13}C$ NMR and UV-Vis spectroscopy. The structure was cbanged after hydrolysis-condensation reaction and drying process. The hydrolysis-condensation rates of modified Ti alkoxide with acetic acid were investigated by $^1H$ NMR spectroscopy. This modified Ti(IV) alkoxide was less reactive toward hydrolysis-condensation reaction than $Ti(OPr^i)_4$, which can be attributed to the stable ligand structure between Ti alkoxide and ligand. The structural change on obtained from gel powders with heat treatment was also observed by FT-IR spectroscopy.

SnO₂가 도핑된 TiO₂ 박막의 합성 및 광촉매 효과

정미원,곽윤정,Jung, Mie-Won,Kwak, Yun-Jung 한국세라믹학회 2007 한국세라믹학회지 Vol.44 No.11

[ $SnO_2$ ]-doped $TiO_2$ thin films were prepared from tin (IV) bis (acetylacetonate) dichloride and titanium diisopropoxide bis (acetylacetonate) with pluronic P123 or degussa P25 as a structural-directing agent. These hydrolyzed sol were spin coated onto Si(100) wafer substrate. The microstructure, morphology and bonding states of thin films were studied by field-emission scanning electron microscopy (FE-SEM), X-ray diffractometry (XRD), and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity of these films was investigated by using indigo carmine solution.

La_0.8Ca_0.2MnO₃의 합성 및 특성연구

정미원,이지윤,김현정 한국세라믹학회 2003 한국세라믹학회지 Vol.40 No.5

초거대 자기 저항 물질인 페로브스카이트 L $a_{0.8}$C $a_{0.2}$Mn $O_3$의 분말을 졸-겔방법으로 제조하였다. Lanthanum(III), Calcium(II) 그리고 Manganese(III) 2,4-Pentanedionate를 Propionic acid와 methane떠 혼합용매를 사용하고 PEG (l5 wt%) 용액을 첨가 하여 안정한 졸용액을 합성하였고 FT-IR spectroscopy로 반응의 진행 정도를 관찰하였다. L $a_{0.8}$C $a_{0.2}$Mn $O_3$ 겔 분말에 대해 온도를 변화시키면서 열처리하여 FT-IR, CP/MAS $^{13}$C solid state NMR spectroscopy와 XRD등을 이용해 구조변화를 관찰하였다. 열분석은 TG/DTA로 측정하였으며, FE-SEM을 통해 입자크기와 균일도를 관찰하였고, 양이온 조성 비율을 알아보기 위해 ICP-AES를 측정하였다. 자성 특성을 규명하기 위해 VSM을 이용하여 자기 모멘트를 측정하였으며, 상자기성 에서 강자기성으로 전이되는 큐리온도( $T_{c}$)를 관찰하였다. The powders of L $a_{0.8}$C $a_{0.2}$Mn $O_3$ Colossal Magnetoresistance (CMR) materials were synthesized by sol-gel process. Lanthanum(H), Calcium(II) and Manganese(III) 2,4-Pentanedionate were dissolved in a mixed binary solution consisted of propionic acid and methanol with PEG (15 wt%) aqueous solution. The progress of reactions was monitored by FT-IR spectroscopy. The Lao scao.2Mn03 gel powders were annealed at various temperatures. The structural changes were investigated by FT-IR, CP/MAS $^{ 13}$C solid state NMR spectroscopy and XRD. The thermochemical property, particle characterization, microstructure of sintered sample, and cation composition of gel powder were studied by TG/DTA, FE-SEM and ICP-AES. The magnetic characterizations were identified through measurement of magnetic moment by VSM.

고분자 P123와 란탄이 도핑된 알루미나의 특성 연구

정미원,이미회,Jung, Mie-Won,Lee, Mi-Hoe 한국세라믹학회 2008 한국세라믹학회지 Vol.45 No.5

To direct the evolution of nanostructure and immobilize ${\gamma}-Al_2O_3$ catalyst, nanocrystalline La-doped-$Al_2O_3$ powder were prepared by the sol-gel process with addition of an amphiphilic block copolymer template (pluronic P123: $(poly(ethyleneoxide)_{20}-poly(propyleneoxide)_{70}-poly(ethyleneoxide)_{20})$. The dried gel is amorphous, whereas heating at temperature above $700^{\circ}C$ leads to the formation of nanocrystalline ${\gamma}$ and ${\delta}-Al_2O_3$ and these two phases is kept until $1100^{\circ}C$. ${\alpha}-A1_2O_3 $starts to form at $1200^{\circ}C$ with $LaAl_{11}O_{18}$. The surface morphology and crystal structure has been observed by field emission scanning electron microscope (FE-SEM) and X-ray diffraction (XRD). Solid state $^{27}Al$ MAS NMR indicates two types of local environment, i.e. octahedral and tetrahedral sites. The surface area and pore size was compared among these powders using the BET nitrogen adsorption measurements.

졸-겔공정에 의해 실리카 구조체에 도입된 유기 NLO 물질의 특성

정미원,문정호,설용건,( Mie Won Jung,Jeong Ho Mun,Yong Gun Shul,Tatsuo Wada ) 한국공업화학회 1993 공업화학 Vol.4 No.3

Organic nonlinear optical materials such as MNA(2-Methyl-4-nitro-aniline), Carbazole 1 (5-Nitro-9-hydroxyethyl Carbazole), Carbazole 2 (5-Nitro-9-ethyl Carbazole) and DR 1(Disperse Red 1) were incorporated into silica matrix to form a composite thin films. The thermal stability and degree of degradation were compared to these organic-inorganic composite film. Among those films, Carbazole 1 and DR 1 which have terminal -OH group showed enhanced stability for thermal degradation. The effect of polarization and degree of relaxation for the composite thin films incorporated with Carbazole 1 were measured by the absorbance change of UV spectra with time. With polarization treatment of Carbazole 1 incorporated composite film, the intensity of UV absorbance was remarkably reduced. And slow relaxation of Carbazole 1 molecule was suggested from the slightly recovered intensity of UV absorbance after removing the electric field at room temperature.

특기병의 가족건강성과 군생활 적응의 관계에서 학업적 자기효능감의 매개효과

정미원,장성화 한국상담심리교육복지학회 2020 상담심리교육복지 Vol.7 No.2

본 연구는 특기병의 가족건강성, 군생활 적응 간의 관계에서 학업적 자기효능감이 매개효과의 역할을 하는지 살펴보고자 한다. 이는 D시에서 특기병 교육을 받는 228명을 대상으로 설문지를 수집하여 상관계수, 구조방정식(SEM), Sobel-test을 통해 매개효과를 알아보았다. 본 연구의 결과는 다음과 같다. 첫째, 특기병의 가족건강성, 학업적 자기효능감, 군생활 적응 간의 상관 결과는 모든 하위변인에서 유의미한 정적상관이 있는 것으로 나타났다. 둘째, 특기병의 가족건강성과 군생활 적응의 관계에서 학업적 자기효능감이 매개효과가 있는지 확인한 결과, 가족건강성, 학업적 자기효능감, 군생활 적응의 구조방정식 모형검증은 모두 적합한 것으로 나타났다. 또한 가족건강성이 군생활 적응에 미치는 설명력에 학업적 자기효능감이 매개효과가 있는 것으로 나타났다. 이 연구의 결론은 가족건강성과 군생활 적응의 상관에서 학업적 자기효능감이 주요한 변인으로 나타났다. 이 결과는 특기병들의 학업적 자기효능감을 높이기 위한 교육 및 상담 개입 프로그램이 개발될 필요성을 제안한다.