• Korean Chemical Engineering Research
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• 제54권2호
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• pp.152-156
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• 2016

Brilliant blue FCF에 대한 분해 특성이 우수한 광촉매를 제조하는 연구를 수행하였다. 먼저 전구체인 titanium (IV) sulfate와 zinc acetate에 침전제로 각각 NaOH, $NH_4OH$를 첨가하여 비교적 낮은 온도와 상압에서 중간상 형성 없이 1단계의 수열합성법으로 $TiO_2$와 ZnO를 제조하였다. $TiO_2$의 경우 제조과정에 양이온성 계면활성제인 CTAB을 첨가하여 제조하기도 하였다. 제조된 $TiO_2$와 ZnO의 결정성, 입자크기, 흡광도 등과 같은 물리적 특성을 확인하기 위해 XRD, Zeta-potential meter, DRS 등을 사용하여 분석하였다. 광촉매적 특성을 확인하기 위해 회분식 반응장치를 이용하여 UV 조사 하에서 brilliant blue FCF의 광분해 특성을 조사하였다. CTAB을 첨가하지 않은 경우, $TiO_2$가 ZnO보다 입자가 작고 흡광도와 광촉매 반응의 초기속도가 큰 것을 확인할 수 있었다. 그리고 동일한 제조조건에서 CTAB을 전구체인 $Ti(SO_4)_2$ 농도의 1/10 첨가하여 제조한 $TiO_2$는 CTAB을 첨가하지 않은 것보다 brilliant blue FCF의 최종 제거율이 약 15% 정도 우수하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1989년도 춘계학술대회 논문집
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• pp.70-73
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• 1989

(1-x-y)Pb($Zn_{1/3}Nb_{2/3})O_3-Ba(Zn_{1/3}Nb_{2/3})O_3-PbTiO_3(0.12{\leq}x{\leq}0.21, 0.24{\leq}y{\leq}0.33$) ternary compound ceramics were fabricated by the mixed oxide method. The sintering temperature and time were 1050 [$^{\circ}C$], 2[hr]. Morphotropic phase boundary region was chosen for the composition. 0.55 PZN-0.21 BZN-0.24 PT specimen had the highest value of relative dielectric constants, 5353. The curie temperature of specimens were increased linearly with PT content. Near the morphotropic phase boundary, electro-mechanical coupoling factor and mechanical quality factor of the specimens had the highest values.

• 한국세라믹학회지
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• 제21권2호
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• pp.121-126
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• 1984

The dielectric properties of $BaTiO_3$ containing 0~0.3mol% and ZnO respectively as additives were investigated as a function of temperature from $25^{\circ}C$ to 14$0^{\circ}C$ and frequency from 24 KHz to 15MHz. The density of sintered $BaTiO_3$ was increased with addition of increasing to 0.15mol% amounts of $Sb_2O_3$ and the dielectric constant was also increased. This is due to space charge polarization with Ba vacancies. Above 0.15mol% $Sb_2O_3$ the density was decreased and the dielectric constant was also decreased due to occuring the discharge through voids. The density of sintered $BaTiO_3$ was decreased with addition of increasing to 0.15mol% amounts of ZnO and the dielectric constant was decreased due to occuring the discharge through voids. Above 0.15mol% ZnO the density was increased and the dielectric constant was also increased.

• Transactions on Electrical and Electronic Materials
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• 제14권6호
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• pp.312-316
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• 2013

In this study, short-circuit preventive layer (blocking layer) was deposited between conductive transparent electrode and porous $TiO_2$ film in the DSSCs. As blocking layer, we selected the metal-oxide such as $TiO_2$, $Nb_2O_5$ and ZnO. The sheet resistance with each different blocking layers were 18 ${\Omega}/sq.$ for the $TiO_2$, 10 ${\Omega}/sq.$ for the $Nb_2O_5$ and 8 ${\Omega}/sq.$ for the ZnO, while the RMS (Root Mean Square) roughness value of DSSCs were 39.61 nm for the $TiO_2$, 41.84 nm for the $Nb_2O_5$ and 36.14 nm for the ZnO respectively. From the results of photocurrent-voltage curves, a sputtered $Nb_2O_5$ blocking layer showed higher performance on 2.64% of photo-electrochemical properties. The maximum of conversion efficiency which was achieved under 1 sun irradiation by depositing the blocking layer increased up to 0.56%.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.682-683
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• 2006

Thermoelectric conversion efficiency of thermoelectric elements can be increased by using a structure combining n-type and p-type semiconductors. From the above point of view, attention was directed at ZnO as a candidate n-type semiconductor material and investigations were made. As the result, a dimensionless figure of merit ZT close to 0.28 (1073K) was obtained for specimens produced by the PCS (Pulse Current Sintering) method with addition of specified quantities of $TiO_2$, CoO, and $Al_2O_3$ to ZnO. It was found that the interstitial $TiO_2$ in the ZnO restrains the grain growth and CoO acts onto the bond between grains. The influence of the inclusion of $TiO_2$ and CoO onto the sintering behavior also was investigated.

• 한국세라믹학회지
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• 제42권4호
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• pp.276-281
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• 2005

산소분위기, $750^{\circ}C$서 36 h 동안 하소함으로써 연소법에 의해 $LiNi_{1-y}M_{y}O_{2}(M=Zn^{2+},\;Al^{3+},\;and\;Ti^{4+},\;0.000\{\le}y{\le}0.100)$를 합성하였다. 각 시료에 대해 XRD 분석, FE-SEM 관찰, 싸이클 수에 따른 방전 용량의 변화 조사가 행해졌다. $LiNi_{0.99}M_{0.01}O_{2}$ (M=Zn, Al, and Ti) 조성이 여러 조성 중에서 대체로 우수한 전기화학적 특성을 나타내었다. 결정성과 cation mixing의 평가에서 Zn을 치환한 경우 결정성이 나쁘게 나타났고 Ti를 치환한 경우 cation mixing이 크게 나타났으며, Al을 치환한 경우 결정성이 좋고 cation mixing이 적게 나타났다. Al을 치환한 경우 싸이클 특성이 개선되었다.

• 대한전자공학회논문지
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• 제26권8호
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• pp.1211-1216
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• 1989

To enhance the breakdown properties of low voltage-oriented ZnO varistor, sample were fabricated with additive oxides and sintering conditions. Addition of TiO2 lowered breakdown voltage` nonlinear resistances were lowered about 10V/mm and nonlinear exponents were not lowered with respect to it with the basic composition. To the samples added TiO2, V2ko5, and Cr2O3, microstructures were observed by SEM, moreover Ti was detected at grainboundaries and within the grain by EDS. Addition of Si-oxides and Sb2O3 increased nonlinear exponent and also increased nonlinear resistance, by addition of TiO2 to these samples at the sintering conditions of 1250\ulcorner and 1 hour we could fabricate low voltage-oriented ZnO varistors with nonlinear exponent of 30 or more and with real breakdown voltage of 30V/mm.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1988년도 추계학술대회 논문집
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• pp.8-11
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• 1988

(1-x-y)Pb($Zn_{1/3}Nb_{2/3})0_3-BaTiO_3PbTiO_3(0.05{\leq}x{\leq}0.20, 0.05{\leq}y{\leq}0.15$) ternary compound ceramics were fabricated by the mixed oxide method. The dielectric properties with temperature and frequency of the specimens were investigated. Relative dielectric constants of the specimens were increased with $BaTiO_3$ contents. Increasing the $BaTiO_3$contents, the variation in the relative dielectric constant with frequency, the temperature coefficient of capacitance (TCC) and the dielectric loss were decreased.

• 한국세라믹학회지
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• 제30권11호
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• pp.925-932
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• 1993

The perovskite phase in PZN-PMN-PT (Pb(Zn, Mg)1/3Nb2/3O3-PbTiO3) pseudoternary ceramics was stabilized by the addition of excess constituent divalent oxides (PbO, MgO and ZnO). The excess addition of 5mol% MgO or 7.5mol% PbO fully stabilized the perovskite phase. The enhanced diffuse phase transition (DPT) and the decrease in the electrical resistivity observed in the presence of excess ZnO or MgO were interpreted in terms of the additional formation of negatively charged, short-range ordered 1:1 domains with a concomitant generation of charge carriers, holes.

• 한국세라믹학회지
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• 제39권5호
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• pp.438-445
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• 2002

본 연구에서는 $PbO-TiO_2-SiO_2-BaO-ZnO-Al_2O_3-CaO-B_2O_3-Bi_2O_3-MgO$계의 유리를 $1,400{\circ}C$에서 용융시킨 후, 급랭, 분쇄하여 glass frit을 제조하였다. Glass frit 분말을 일축가압성형한 후 $750~1,000{\circ}C$의 온도범위에서 2시간 동안 소성 및 결정화 하였다. Glass frit의 결정화는 $750{\circ}$ 전후의 온도에서 시작되었고, 저온에서의 주된 결정상은 $Al_2O_3$와 hexagonal celsian($BaAl_2Si_2O_8$)이었다. 소성온도가 높아지면서 monoclinic celsian, $ZnAl_2O_4,\;Zn_2SiO_4,\;CaTi(SiO_4)O,\;TiO_24 등이 주된 결정상으로 나타났고, 특히 celsian은 hexagonal에서 monoclinic으로 상전이가 발생하였다. 그리고 15wt%의 PbO를 첨가한 glass frit에만 $PbTiO_3-CaTiO_3$ 고용체가 나타났다. 1MHz 대역에서 유전특성을 살펴본 결과 유전상수는 11~16이었고, 유전손실은 0.020 미만이었다. 그러나 15wt%의 PbO를 첨가한 glass frit의 경우는 $PbTiO_3-CaTiO_3$ 고용체 결정상의 존재로 유전상수가 17~26으로 높았고, 유전손실은 0.010~0.015로서 다른 조성들에 비하여 우수한 특성을 나타내었다.