• 대한환경공학회지
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• 제28권4호
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• pp.368-375
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• 2006

순수한 아나타제 구조로 이루어진 DT51D $TiO_2$에 $CrO_x,\;FeO_x,\;MnO_x,\;LaO_x,\;CoO_x,\;NiO_x,\;CeO_x,\;CuO_x$와 같은 단일 산화물 촉매를 각각 5 wt.% 담지하여 모델반응으로 선택한 기상 TCE 제거반응을 수행하였으며, 이로부터 얻어진 결과를 바탕으로 $CrO_x/TiO_2$-based 복합 산화물 촉매상에서 TCE 산화반응을 연구함으로써 유해 중금속의 사용량을 최소화하기 위한 최적의 촉매 디자인 방법을 도출하고자 하였다. DT51D $TiO_2$에 담지된 여러 단일 금속 산화물들 중에서 기상 TCE 제거반응에 대하여 $CrO_x$가 가장 우수한 촉매활성을 보이는 것으로 나타났으며, 반응온도의 함수로 얻어진 TCE 제거반응의 활성은 $CrO_x$의 담지량에 의존하였다. 5 wt.% $CrO_x$-based 복합 산화물 촉매는 10 wt.% $CrO_x$만으로 이루어진 단일 산화물 촉매와 거의 동일한 수준의 TCE 제거반응 활성을 보였을 뿐만 아니라 이 복합 산화물 촉매들은 10 wt.% $CoO_x,\;MnO_x,\;FeO_x,\;NiO_x$ 등과 같은 단일 산화물 촉매들보다 높은 반응활성을 갖는 것으로 나타났다. 단일 산화물 촉매의 반응활성과 비교하였을 때 5 wt.% $CrO_x$-based 복합 산화물 촉매상에서 TCE 제거반응 동안에 얻어지는 반응활성의 증가 정도는 $420^{\circ}C$ 이하의 반응온도 기준으로 약 $10{\sim}80%$ 이상이었다. 따라서, CVOCs 제거반응을 위하여 널리 사용되고 있는 단일 $CrO_x/Al_2O_3$ 촉매보다는 $CrO_x$의 사용량을 최소화하면서도 우수한 반응활성을 얻을 수 있는 $CrO_x/TiO_2$-based복합 산화물 촉매가 보다 바람직하며 하나의 대안적인 촉매 디자인 방법으로 응용될 수 있을 것으로 생각된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 C
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• pp.1257-1261
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• 1994

Phsysical and dielectric properties of $(1-x)CaTiO_3-xLa(Zn_{1/2}Ti_{1/2})O_3$ ceramics were investigated at the temperature range of $25^{\circ}C$ to $80^{\circ}C$ at the frequency of 6 GHz. As increasing addition of the amount of $La(Zn_{1/2}Ti_{1/2})O_3$ to x = 5 mol,Q value was increased due to grain growth and increase of density. For more addition, Q value decreased due to electrical defect. Temperature coefficient of resonant frequency could be controlled by the amount of $La(Zn_{1/2}Ti_{1/2})O_3$, which could be explained by volume mixing rule.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.865-868
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• 2000

It was examined that the relationship between microstructures, electrical properties and crystal structure of (1-x)CaMnO$_3$-xCaTiO$_3$solid solution system which was made by mixing a semiconducting material CaMnO$_3$of low resistance and a dielectric material CaTiO$_3$of high resistance with variable ratios (x=0, 0.1, 0.3, 0.5, 0.7, 0.9, 1.0). As the CaTiO$_3$increased, the resistance, B constant and lattice constant were increased, but the grain size was decreased. On particular, above 50wt% of CaTiO$_3$, the resistance at 2 5$^{\circ}C$ was rapidly increased due to the correlation in connectivity of the lattices between the conductive Mn$^{+4}$ octahedron and the insulative Ti$^{+4}$ octahedron.ron.

• 한국세라믹학회지
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• 제30권6호
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• pp.441-448
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• 1993

The Ba1-xSrxTiO3 thin films deposited on ITO-coated glass substrate at 55$0^{\circ}C$ by rf magnetron sputtering method have individual preferential orientations as a function of composition (X=0, 0.25, 0.5, 0.75, 1) due to the stress relief interactions among the intrinsic compressive stress, thermal tensile stress adn extrinsic compressive stress (compressive stress in case of BaTiO3(Tc=12$0^{\circ}C$) and Ba0.75Sr0.25TiO3(Tc=57$^{\circ}C$)). This behavior also appears on the (BaSr)TiO3 thin films (X=0.5) deposited on ITO-coated glass substrate at deposition temperature between 35$0^{\circ}C$ and 55$0^{\circ}C$. The composition of Ba1-xSrxTiO3 thin films deposited on ITO-coated glass substrate at 55$0^{\circ}C$ is close to stoichiometry (1.009~1.089 in A/B ratio), but the compositional deviation from a stoichiometry is larger as SrTiO3 is added. The morphology of Ba1-xSrxTiO3 thin films is very similar for over all substrate temperatures, and the roughness due to the differences of cluster size is the smallest at X=0.25.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.843-846
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• 2000

The (1-x)MgTiO$_3$-xSrTiO$_3$(x=0.02∼0.08) ceramics were fabricated by conventional mixed oxide method. The sintering temperature and time were 1250$^{\circ}C$∼1400$^{\circ}C$, 2hr., respectively. The structural and microwave dielectric properties were investigated by varying sintering temperature and composition ratio. In the (1-x)MgTiO$_3$-xSrTiO$_3$(x=0.02) ceramics, the cubic SrTiO$_3$and hexagonal MgTiO$_3$phases were coexisted. The dielectric constant was increased and the temperature coefficient of resonant frequency( $\tau_f$) was decreased with addition of SrTiO$_3$. The temperature coefficient of resonant frequency($\tau_f$) was gradually varied from negative value to positive value with increasing the SrTiO$_3$.

• 대한환경공학회지
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• 제31권11호
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• pp.1019-1024
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• 2009

가시광 활성을 갖는 anatase 결정구조의 $TiO_2-_xN_x$ 나노입자를 암모니아 수용액에서 $TiCl_4$ 가수분해에 의해 제조하였다. 제조한 시료의 특성은 XRD, TEM, $N_2$-sorption 및 DRS로 분석하였다. 질소를 $TiO_2$에 도핑함으로써 광흡수 영역이 순수한 TiO2에 해당하는 390 nm에서 가시광 영역인 530 nm까지 이동하였다. DRS 분석결과로부터 $TiO_2-_xN_x$의 밴드갭이 감소하는 것을 유추할 수 있었다. 광촉매 활성은 가시광 조사하에서 congo red 분해로부터 평가하였다. 질소의 도핑 농도가 적절한 광촉매가 광촉매 활성이 가장 높게 나타났다. 이러한 결과로부터 질소 도핑이 광촉매 활성의 향상에 중요한 역할을 함을 확인할 수 있었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 C
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• pp.795-797
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• 1998

A $BaTiO_3$, ferroelectric material, was mixed $SrTiO_3$, $(x)BaTiO_3-(1-x)SrTiO_3$($0.7{\leq}x{\leq}1$) ceramic capacitor with stable electrical properties in high voltage was fabricated. And microstructure, electrical property were investigated with $SrTiO_3$ mol ratio. The shrinkage, open porosity, sintering density were predominated at $9BaTiO_3-0.1SrTiO_3$. Increasing $SrTiO_3$ mol ratio, curie temperature was shifted at low temperature and maximum permittivity was increased. Also, $0.9BaTiO_3-0.1SrTiO_3$ was showed stable dielectric properties at $25{\sim}80[^{\circ}C]$. V-I properties of specimen were observed in the temperature range of $21{\sim}143[^{\circ}C]$, were divided into three regions. The region I below 10[kV/cm] was shown Ohmic conduction, the region II from 10 to 30[kV/cm] was explained by the Poole-Frenkel emission theory and the region III above 30[kV/cm] was analysed by the tunneling effect.

• 한국세라믹학회지
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• 제34권9호
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• pp.921-926
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• 1997

Two NbCx-C1-x/Y2O3/Ti sputter-coated Al2O3 substrates (L 5.5 cm$\times$W 0.5 cm) were diffusion bonded together using hot press method at 95$0^{\circ}C$ for 3 hours under 1 MPa of applied pressure. 4 points bending tests were used to evaluate the mechanical performance of these precracked laminate beams. Two types of mechanical responses were observed: crack penetration through the interface for x=0.75, 1 and crack deflection into an interface for x=0.25, 0.5. The Al2O3/NbCx-C1-x/Y2O3/Ti system suggested here has been proves to be effective for the thermokinetical stability and tailorability of the interfaces of Al2O3/Ti composites at 95$0^{\circ}C$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.155-159
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• 2003

Polycrystalline $Ti_{1-x}Co_xO_2$ thin films on $SiO_2$ (200 nm)/Si (100) substrates were prepared using liquid-delivery metalorganic chemical vapor deposition. Microstructures and ferromagnetic properties were investigated as a function of doped Co concentration. Ferromagnetic behaviors of polycrystalline films were observed at room temperature, and the magnetic and structural properties strongly depended on the Co distribution, which varied widely with doped Co concentration. The annealed $Ti_{1-x}Co_xO_2$ thin films with $x{\leq}0.05$ showed a homogeneous structure without any clusters, and pure ferromagnetic properties of thin films are only attributed to the $Ti_{1-x}Co_xO_2$ (TCO) phases. On the other hand, in case of thin films above x=0.05, Co clusters formed in a homogeneous $Ti_{1-x}Co_xO_2$ Phase, and the overall ferromagnetic (FM) properties depended on both $FM_{TCO}$ and $FM_{Co}$. Co clusters with about 10nm-150nm size decreased the value of Mr (the remanent magnetization) and increased the saturation magnetic field.

• 공업화학
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• 제25권6호
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• pp.645-647
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• 2014

본 연구에서는 수열합성법을 이용하여, 한단계의 과정으로 $TiO_2$와 Ru (Ruthenium)가 도입된 $TiO_2$ ($Ru_x/TiO_2$)를 합성하였다. 합성된 샘플의 결정성과 조성 및 형태를 X-ray diffraction (XRD)과 energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM)를 통하여 확인하였으며, Benzyl alcohol의 Benzaldehyde로의 산화반응에 촉매로서 적용하였다. 높은 선택성을 가지는 산화반응이 진행되었으며, $TiO_2$에 도입된 Ru의 양이 증가할수록 촉매로서의 더 좋은 촉매활성을 보였다.