• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1996년도 춘계학술대회 논문집
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• pp.63-67
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• 1996

In this paper, effect of MnO$_2$ addition(0, 0.1, 0.2, 0.3, 0.5wt%) on the microstructure, dielectric and piezoelectric properties of [xPMW - (0.15-x) PNN] - [yPT-(0.85-y)PZ] (x=0, 0.01, 0.02, 0.03, 0.05, y = 0.35, 0.40, ().425, 0.45, 0.5) were investigated. When Ti/Zr ratio was 1.0, dielectric and piezoelectric properties were highest value. With PMW 2mol%, dielectric constant, dielectric constant (d$\_$33/, d$\_$31/) and electromechanical coupling factor (kp, k$\_$31/) were highest values of 1995, 479, 186(x10$\^$-12/C/N), 0.61, 0.36, respectively. With the addition of MnO$_2$, dielectric constant, electromechanical coupling factor (kp, k$\_$31/) were decreased, but with 0.3wt% MnO$_2$, eletromechanical coupling factor was highest value of 0.63. With the addition of MnO$_2$, mechanical quality(Q$\_$m/ was increased.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1995년도 제9회 학술발표회 논문개요집
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• pp.41-41
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• 1995

• 한국분말재료학회지
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• 제8권3호
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• pp.163-167
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• 2001

A bulk porous $CaZrO_3/MgO$ composite with plantinum nano-dispersion was synthesized in air atmosphere through the combination of several in situ reactions, including the pyrolysis of $PtO_2$. A mixture of $CaMg(CO_3)_2$(dolomite), $ZrO_2$, $PtO_2$ and LiF (0.5 wt%, as an additive) was cold isostatically pressed at 200 MPa and sintered at $1100^{\circ}C$ for 2 h. The porous $CaZrO_3/MgO/Pt$ composite ($CaZrO_3/MgO$ : Pt=99 : 1 in volume) had a uniformly open-porous structure (porosity: 56%) with three-dimensional (3-D) network and a narrow pore-size distribution, similarly to the porous $CaZrO_3/MgO$ composites reported before. Catalytic Properties (viz., NO direct decomposition and NO reduction by $C_2H_4$) of the $CaZrO_3/MgO/Pt$ composite were investigated up to $900^{\circ}C$. In the absence of oxygen, the NO conversion rate reached ~52% for the direct decomposition and ~100% for the reduction by $C_2H_4$, respectively. The results suggest the possibility of the porous composite as a multifunctional filter, i.e., simultaneous hot gas-filtering and $de-NO_x$ in one component.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제50권10호
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• pp.504-508
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• 2001

The$(Sr_{1-x}Ca_x)TiO_3$(SCT) thin films are deposited on Pt-coated electrode $(Pt-TiN /SiO_2Si)$ using RF sputtering method at various deposition temperature. The crystallinity of thin films was increased with increased of deposition temperature n the temperature range of 200~500 $[^{\circ}C]$. The capacitance changes almost linearly in temperature ranges of -80~+90$[^{\circ}C]$. All SCT thin films used in the study the phenomena of dielectric relaxation with the increase of frequency, and the relaxation frequency is observed above 200[kHz]. V-I characteristics of SCT thin films show the increasing leakage current with the increases of deposition temperature.

• 공업화학
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• 제10권1호
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• pp.58-66
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• 1999

알루미나에 담지한 $CrO_x$ 촉매를 이용하여 $200{\sim}400^{\circ}C$의 온도 구간에서 공기 중 vinyl chloride의 산화반응을 조사하였다. 탄소를 포함하는 주생성물은 CO 및 $CO_2$로, 온도의 증가에 따라 $CO_2$의 선택도는 증가하고 CO는 감소하였다. 이로부터 $CrO_x$ 촉매상에서 vinyl chloride는 먼저 CO로 일차산화 후 다시 $CO_2$로 완전산화됨을 알 수 있었다. 반응물에 HCl을 첨가하였을 때 vinyl chloride의 전환율은 변화가 없었으나 $CO_2$의 선택도는 감소하였는데 이는 주반응생성물인 HCl이 vinyl chloride의 $CO_2$로 완전산화를 방해함을 의미한다. 반응물에 물이 없는 조건하에서 vinyl chloride를 산화시킬 때 상당량의 $Cl_2$가 생성되었으나 물을 첨가 시 $Cl_2$는 검출되지 않았다. Vinyl chloride의 촉매산화반응에 대한 $CrO_x$ 담지촉매와 몇가지 귀금속 및 다른 전이 금속 산화물의 활성을 비교하였는데 $CrO_x$ 담지촉매의 vinyl chloride 분해활성은 1% Pt 담지촉매를 제외한 다른 촉매에 비해 높았으며, $275^{\circ}C$에서 12% $CrO_x/Al_2O_3$의 반응속도를 기준으로 각 촉매의 활성을 비교시 1% $Pt/Al_2O_3$ 보다 1.2배정도 활성이 떨어지나 다른 촉매에 비하여 각각 3배에서 8배 가량 높은 활성을 나타내었다.

• 한국산학기술학회논문지
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• 제10권9호
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• pp.2390-2395
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• 2009

공간속도 $30000\;hr^{-1}$에서 Fe/ZSM-5 촉매의 $SiO_2/Al_2O_3$ 몰비가 감소함에 따라 $NO_x$ 제거 수율은 증가하였다. Fe/ZSM-5는 반응 온도 $350^{\circ}C$ - $400^{\circ}C$ 사이에서 최대 50%의 질소 산화물 제거 수율을 나타내지만 높은 CO 발생량이 관찰된다. Fe/ZSM-5 촉매에서 생성되는 CO를 제거하기 위하여 Co-Pt/ZSM-5 촉매를 직렬로 연속하여 사용하였으며, 공간속도 $30000\;hr^{-1}$, 반응 온도 $250^{\circ}C$ 조건에서 90% 이상의 질소 산화물과 CO 제거 수율을 나타내었다.

• Bulletin of the Korean Chemical Society
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• 제35권8호
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• pp.2519-2522
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• 2014

Recently, the observation of the electrocatalytic behavior of individual nanoparticles (NPs) by electrochemical amplification method has been reported. For example, the Iridium oxide ($IrO_x$) NP collision on the Pt UME was observed via electrocatalytic water oxidation. However, the bare Pt UME had poor reproducibility for the observation of NP collision signal and required an inconvenient surface pre-treatment for the usage. In this manuscript, we has been investigated other metal electrode such as Cu UME for the reproducible data analysis and convenient use. The $IrO_x$ NP collision was successively observed on the bare Cu UME and the reproducibility in collision frequency was improved comparing with previous case using the $NaBH_4$ pre-treated Pt UME. Also, the adhesion coefficient between NP and the Cu UME was studied for better understanding of the single NP collision system.

• 한국재료학회지
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• 제12권2호
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• pp.160-165
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• 2002

High-frequency dielectric and microwave absorbing properties have been investigated in ferroelectric materials (BaTiO$_3$(BT), (1-x)Pb$Mg_{\frac{1}{3}}Nb_{\frac{2}{3}}$)O$_3$-xPbTiO$_3$(PMN-PT), (1-x)Pb$Mg_{\frac{1}{3}}Nb_{\frac{2}{3}}$O$_3$-xPb(Zn_{\frac{1}{3}}Nb_{\frac{2}{3}}$)O$_3$(PMN-PZN) for the aim of thin microwave absorbers in the frequency range of mobile telecommunication. The specimenns are prepared by conventional ceramic processing and complex permittivity has been measured by transmission/reflection method. The ferroelectric materials show high dielectric constant and dielectric loss in the microwave range and their domiant loss mechanism is considered to be domain wall relaxation. The microwave absorbance of BT 0.9PMN-0.1PT, and 0.8PMN-0.2PZN specimen (determined at 2) are found to be 99.5% (at a thickness of 4.5 mm), 50% (2.5 mm), and 30% (2.5 mm), respectively. It is suggested that PMN-PT or PMN-PZN ferroelectrics are good candidate materials for the spacer of λ/4 absorber. The use of ferroelectric materials is effective in reducing the thickness of absorber with their advantage of high dielectric constant.

• 한국광학회:학술대회논문집
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• 한국광학회 2005년도 제16회 정기총회 및 동계학술발표회
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• pp.76-77
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• 2005

• 한국광학회:학술대회논문집
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• 한국광학회 2005년도 제16회 정기총회 및 동계학술발표회
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• pp.74-75
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• 2005