• 대한화학회지
• /
• 제33권5호
• /
• pp.558-567
• /
• 1989

여러가지 조성비로 만든 Cu/ZnO계 촉매로 이산화탄소를 수소화시켜 메탄올을 합성하였다. 촉매제조시 각 성분의 조성비가 촉매활성에 미치는 영향을 조사하고 반응촉매에 대하여 표면적 측정(BET), 주사전자현미경 측정(SEM), X선회절분석(XRD), X선광전자분석(XPS) 등을 실시하여, 각 촉매의 촉매특성을 조사하고 촉매활성과의 연관성을 연구하였다. 반응생성물은 메탄올과 일산화탄소 뿐이었는데 메탄올의 생성은 CuO의 함량이 증가하면 그에 따라 점차 증가하였으나 CuO:ZnO의 조성비율이 30:70일 경우에 최대이었고, CuO가 70 이상이면 급격하게 감소하였다. 촉매에 대한 SEM 측정과 BET 측정결과에서 확인된 바와 같이 이점은 미세결정크기가 증가되고 표면적이 감소하는 점과 일치되었다. 또 XPS 측정결과에서 촉매표면상에서의 Cu의 농도는 Cu/Cu+Zn(atomic ratio)을 비교할 때 CuO의 함량이 50% 이상인 경우에서 현저히 감소하였다. 그리고 각 촉매들의 $Cu(2P^3)$에 대한 결합에너지의 수치상의 값은 거의 같았으나 환원된 상태의 $Cu(2P^3)$의 결합에너지는 소성된 상태의 것과 비교하여 낮아졌고, 표면에 분포된 Cu 는 대부분 $Cu^{\circ}$로 확인되었으며 CuO:ZnO의 조성이 30:70인 경우에서 최대가 되었다. 이것은 또한 CuO의 조성비율이 30인 때에 메탄올생성이 최대라는 실험결과와도 잘 일치하였다. 그리고 환원된 각각의 촉매로 펄스(pulse)형태의 반응기에서 이소프로판올을 분해시킨 결과 아세톤의 생성율이 프로필렌보다 컸음으로 이들은 염기성이 상대적으로 강한 촉매라고 추측하였다.

• 한국분말재료학회지
• /
• 제6권4호
• /
• pp.301-306
• /
• 1999

Mechanical properties of oxide based materials could be improved by nanocomposite processing. To investigate optimum route for fabrication of nanocomposite enabling mass production, high energy ball milling and Pulse Electric Current Sintering (PECS) were adopted. By high energy ball milling, the $Al_2O_3$-based composite powder with dispersed Cu grains below 20 nm in diameter was successfully synthesized. The PECS method as a new process for powder densification has merits of improved sinterability and short sintering time at lower temperature than conventional sintering process. The relative densities of the $Al_2O_3$-5vol%Cu composites sintered at $1250^{\circ}C$ and $1300^{\circ}C$ with holding temperature of $900^{\circ}C$ were 95.4% and 95.7% respectively. Microstructures revealed that the composite consisted of the homogeneous and very fine grains of $Al_2O_3$ and Cu with diameters less than 40 nm and 20 nm respectively The composite exhibited enhanced toughness compared with monolithic $Al_2O_3$. The influence of the Cu content upon fracture toughness was discussed in terms of microstructural characteristics.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 1998년도 공동 심포지엄 및 추계학술발표회
• /
• pp.195-200
• /
• 1998

토양내에 있어 중금속의 총량 분석만으로는 오염 토양에 대한 환경 평가를 위한 충분한 자료가 되지 못한다. 또한 중금속의 토양내 위해성은 중금속과 토양과의 화학적 상호작용에 의해 결정되기 때문에 중금속의 화학적 형태를 규명하는 것은 토양 환경에 있어서 그들의 이동성과 거동 특성을 평가하는데 중요한 자료가 된다. 연속 추출법은 구봉 광산의 광미로 부터 Cd, Cu, Pb을 화학적 형태에 따라 분리하고, 인위적으로 중금속을 포화시킨 광미와 두밭토양에 있어 중금속의 토양내 거동 특성을 예측하기 위하여 이용되었다. 광미중 Pb의 대부분은 Fe-Mn oxide, carbonate의 결합 형태로 존재하였으며, Cu와 Cd은 각각 71.8%와 42.9%가 유기물, carbonate의 결합형태로 존재하였다. 상당량의 Cd(94.9%), Cu(95.1%), 그리고 Pb(85.8%)은 토양내 잠재적으로 이동 가능한 형태로 존재하였다. 유성과 논산의 밭토양 에 가해진 Cd는 대부분 이동성이 가장 높은 치환태로 존재하였으며, 유성과 논산 토양에서 각각 67.9%와 93.2%가 치환태로 존재하였다. 토양에 가해진 Cd, Cu, Pb은 대부분 이동이 용이한 형태로 존재하였으며, 토양과의 결합세기는 Pb > Cu > Cd 순으로 감소하였다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2010년도 하계학술대회 논문집
• /
• pp.209-209
• /
• 2010

Multiferroic properties of $BaTiO_3-CuFe_2O_4$ thin films grown on highly-textured Pt(111)/$TiO_2/SiO_2$/Si(100) substrates were studied. $CuFe_2O_4$ ceramic target was synthesized by mixing oxide powders of CuO, $Fe_2O_03$, $BaTiO_3$ ceramic target was also prepared separately. The film structure was of bi-layer type, where $BaTiO_3$ layer lies underneath of $CuFe_2O_4$ layer, where both layers were grown by pulsed laser deposition technique. We will report the ferroelectric and magnetic properties of $BaTiO_3-CuFe_2O_4$ bi-layer films in some detail.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1988년도 춘계학술대회 논문집
• /
• pp.3-6
• /
• 1988

Electrical and magnetic properties of $Y_1Ba_2Cu_3O_7-y$ sintered with $Bi_2O_3$ have been investigated by levitation experiment and the measurement of electrical resistivity. The effects of $Bi_2O_3$ addition on the microstructure of the sintered specimens were also investigated. The electrical resistivity in the normal state is smaller in $Y_{0.85}Bi_{0.15}Ba_2Cu_3O_{7-y}$, where the Bi is substituted into Y site, than in the basic compound $Y_1Ba_2Cu_3O_{7-y}$ due to improved microstructure. On the other hand, the microstructure is poor and electrical resistivity is larger in the $Y_1Ba_2Cu_3O_{7-y}$ sintered with excess $Bi_2O_3$. It appears that the impurity in grain boundary affect the electrical properties significantly but has little effect on the magnetic property.

• 한국재료학회지
• /
• 제25권11호
• /
• pp.622-629
• /
• 2015

Cu circuits were successfully fabricated on flexible PET(polyethylene terephthalate) substrates using wettability difference and electroless plating without an etching process. The wettability of Cu plating solution on PET was controlled by oxygen plasma treatment and $SiO_x$-DLC(silicon oxide containing diamond like carbon) coating by HMDSO(hexamethyldisiloxane) plasma. With an increase of the height of the nanostructures on the PET surface with the oxygen plasma treatment time, the wettability difference between the hydrophilicity and hydrophobicity increased, which allowed the etchless formation of a Cu pattern with high peel strength by selective Cu plating. When the height of the nanostructure was more than 1400 nm (60 min oxygen plasma treatment), the reduction of the critical impalement pressure with the decreasing density of the nanostructure caused the precipitation of copper in the hydrophobic region.

• 한국분말재료학회지
• /
• 제14권5호
• /
• pp.292-297
• /
• 2007

The present study was focused on the synthesis of a $TiB_2$ dispersed copper matrix composite material by the combination of the mechanical milling and plasma activated sintering processes. The $Cu/TiB_2$ mixed powder was prepared by the combination of the mechanical milling and reduction processes using the copper oxide and titanium diboride powder as the raw material. The synthesized $Cu/TiB_2$ mixed powder was sintered by the plasma activated sintering process. The hardness and electric conductivity of the sintered bodies were measured using micro vickers hardness and four probe method, respectively. The relative density of $Cu/TiB_2$ composite material sintered at $800^{\circ}C$ showed about 98% of theoretical density. The $Cu-1vol%TiB_2$ composite material has a hardness of about 130Hv and an electric conductivity of about 85% IACS. The hardness and electric conductivity of $Cu-3vol%TiB_2$ composite material were about 140 Hv and about 45% IACS, respectively.

• Current Photovoltaic Research
• /
• 제8권2호
• /
• pp.60-65
• /
• 2020

In perovskite solar cells with planar heterojunction configuration, selection of proper charge-transporting layers is very important to achieve stable and efficient device. Here, we developed solution processible Cu doped NiO_x (Cu:NiO_x) thin film as a hole-transporting layer (HTL) in p-i-n structured methylammonium lead trihalide (MAPbI₃) perovskite solar cell. The transmittance and thickness of NiO_x HTL is optimized by control the spin-coating rate and Cu is additionally doped to improve the surface morphology of undoped NiO_x thin film and hole-extraction properties. Consequently, a perovskite solar cell containing Cu:NiO_x HTL with optimal doping ratio of Cu exhibits a power conversion efficiency of 14.6%.

• Journal of Ceramic Processing Research
• /
• 제19권5호
• /
• pp.434-438
• /
• 2018

The sintering behavior of $BaFe_{12}O_{19}$ with the addition of one and three weight % of $CuWO_4$ as a liquid phase sintering aid is studied. Samples are sintered in the temperature range $900-1250^{\circ}C$ and the effect of $CuWO_4$ addition on density, microstructure, phase composition and magnetic properties is examined. Compared to $BaFe_{12}O_{19}$ with no sintering aid addition, addition of 1 wt % $CuWO_4$ retards densification. Addition of 3 wt % $CuWO_4$ promotes densification at lower sintering temperatures but retards densification at temperatures > $1050^{\circ}C$. Three wt % $CuWO_4$ addition induces the formation of $BaWO_4$ and $Ba_3WFe_2O_9$ secondary phases at temperatures ${\geq}1100^{\circ}C$. Addition of $CuWO_4$ causes a decrease in saturation magnetization, remanent magnetization and coercivity.

• Journal of Electrochemical Science and Technology
• /
• 제12권2호
• /
• pp.188-203
• /
• 2021

The specific benefits of the modified films formed on preliminary anodized aluminum, including the versatility of their potential applications impose the need for evaluation of the exploitation reliability of these films. In this aspect, the durability of Cu and Ni modified anodized aluminum oxide (AAO) films on the low-doped AA1050 alloy was assessed through extended exposure to a 3.5% NaCl model corrosive medium. The electrochemical measurements by means of electrochemical impedance spectroscopy (EIS) and potentiodynamic scanning (PDS) after 24 and 720 hours of exposure have revealed that the obtained films do not change their obvious barrier properties. In addition, supplemental analyses of the coatings were performed, in order to elucidate the impact of the AC-deposition of Cu and Ni inside the pores. The scanning electron microscopy (SEM) images have shown that the surface topology is not affected and resembles the typical surface of an etched metal. The subsequent energy dispersive X-ray spectroscopy (EDX) tests have revealed a predominance of Cu in the combined AAO-Cu/Ni layers, whereas additional X-ray photoelectron (XPS) analyses showed that both metals form oxides with different oxidation states due to alterations in the deposition conditions, promoted by the application of AC-polarization of the samples.