• Elastomers and Composites
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• 제56권3호
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• pp.113-116
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• 2021

In this study, we report a facile fabrication of multi-walled carbon nanotubes (MWCNTs)-CuO composites synthesized by a microwave method using MWCNTs and copper oxide (CuO). The number of copper hydrate precursors affect the size and number of CuO domains formed along the MWCNTs in the composites. The domain size is controllable from 239 nm to 348 nm. The composites are characterized by transmission electron microscopy, energy dispersive spectrometry, X-ray diffraction (XRD), Raman spectroscopy, and UV-Vis spectroscopy. The CuO produced in the composites is confirmed to be tenorite with a monoclinic crystal structure through the XRD patterns of (-111), (111) and (-202).

• 한국분말재료학회지
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• 제30권4호
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• pp.332-338
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• 2023

Thermite welding is an exceptional process that does not require additional energy supplies, resulting in welded joints that exhibit mechanical properties and conductivity equivalent to those of the parent materials. The global adoption of thermite welding is growing across various industries. However, in Korea, limited research is being conducted on the core technology of thermite welding. Currently, domestic production of thermite powder in Korea involves recycling copper oxide (CuO). Unfortunately, controlling the particle size of waste CuO poses challenges, leading to the unwanted formation of pores and cracks during thermite welding. In this study, we investigate the influence of powder particle size on thermite welding in the production of Cu-thermite powder using waste CuO. We conduct the ball milling process for 0.5-24 h using recycled CuO. The evolution of the powder shape and size is analyzed using particle size analysis and scanning electron microscopy (SEM). Furthermore, we examine the thermal reaction characteristics through differential scanning calorimetry. Additionally, the microstructures of the welded samples are observed using optical microscopy and SEM to evaluate the impact of powder particle size on weldability. Lastly, hardness measurements are performed to assess the strengths of the welded materials.

• 한국분말재료학회지
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• 제17권4호
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• pp.276-280
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• 2010

In the present work, ethylene glycol-based (EG) copper oxide nanofluids were synthesized by pulsed wire evaporation method. In order to explode the pure copper wire, high voltage of 23 kV was applied to the both ends of wire and argon/oxygen gas mixture was used as reactant gas. EG-based copper oxide nanofluids with different volume fraction were prepared by controlling explosion number of copper wire. From the transmission electron microscope (TEM) image, it was found that the copper oxide nanoparticles exhibited an average diameter about 100 nm with the oxide layer of 2~3 nm. The synthesized copper oxide consists of CuO/$Cu_2O$ phases and the Brunauer Emmett Teller (BET) surface area was estimated to be $6.86\;m^2\;g^{-1}$. From the analyses of thermal properties, it is suggested that viscosity and thermal conductivity of EG-based copper oxide nanofluids do not show temperature-dependent behavior over the range of 20 to $90^{\circ}C$. On the other hand, the viscosity and thermal conductivity of EG-based copper oxide nanofluids increase with volume fraction due to the active Brownian motion of the nanoparticles, i.e., nanoconvection.

• 자원리싸이클링
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• 제9권1호
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• pp.70-75
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• 2000

산화제 제조시 초기 과정에서 $Fe_3O_4$ 가 피복되었고 2 단계에서는 $Fe_3O_4$ 보다 첨착능이 우수한 것으로 알려져 있는 $Fe_3O_4$가 생성되었다. 산화제 폐염삼 30g/l에 5Cu mg/l를 첨가하여 20분간 반응하였을 경우 구리이온 제거효율은 74.8%이었다. 연속실험에서 최종 배출수중의 구리농도가 1mg/l이하를 파괴점으로 보았을 때 파괴점 도달시간은 23시간이었고 흡착용량은 0.87$\cdot$Cu/g$\cdot$IOCS이었다.

• 한국재료학회지
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• 제28권1호
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• pp.32-37
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• 2018

We report on the efficient detection of NO gas by an all-oxide semiconductor p-n heterojunction diode structure comprised of n-type zinc oxide (ZnO) nanorods embedded in p-type copper oxide (CuO) thin film. The CuO thin film/ZnO nanorod heterostructure was fabricated by directly sputtering CuO thin film onto a vertically aligned ZnO nanorod array synthesized via a hydrothemal method. The transport behavior and NO gas sensing properties of the fabricated CuO thin film/ZnO nanorod heterostructure were charcterized and revealed that the oxide semiconductor heterojunction exhibited a definite rectifying diode-like behavior at various temperatures ranging from room temperature to $250^{\circ}C$. The NO gas sensing experiment indicated that the CuO thin film/ZnO nanorod heterostructure had a good sensing performance for the efficient detection of NO gas in the range of 2-14 ppm under the conditions of an applied bias of 2 V and a comparatively low operating temperature of $150^{\circ}C$. The NO gas sensing process in the CuO/ZnO p-n heterostructure is discussed in terms of the electronic band structure.

• 한국세라믹학회지
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• 제37권8호
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• pp.799-804
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• 2000

Coulometric titration experiments have been done for copper doped cobaltous oxide (Co1-xCux)1-$\delta$ O with various dopant concentrations. We present the obtained experimental data and compare our results to those of previous thermogravimetric investigation. The experimental data are fitted by theoretical calculations based on various defect models. For this modeling, we considered different types fo major defects like copper in substitutional and interstitial lattice sites as well as copper vacancy. We also introduced the copper evaporation effect during titration experiment into our consideration.

• 공업화학
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• 제33권6호
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• pp.630-635
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• 2022

멜라민 스펀지를 열처리하여 제조된 질소함유 탄소 스펀지에 산화구리(CuO)를 무전해 도금하여 기판없이 작동하는 일산화질소(NO) 가스 센서를 제조하였다. 탄소 스펀지 표면의 CuO 함량은 도금 시간이 증가함에 따라 증가하였으나, NO 가스 흡착을 유도한다고 알려져 있는 질소의 함량은 CuO 표면 함량이 증가함에 따라 감소하였다. 미처리 탄소스펀지는 NO 가스에 대하여 18 min에 최대 저항 변화(5.0%)를 나타내었다. 반면에, CuO가 도금된 샘플(CuO30s-CS)은 8 min만에 최대 18.3%의 저항변화를 보였다. 이러한 NO 가스 감지 능력 향상은 CuO로 인하여 탄소 스펀지의 정공 캐리어 수 증가 및 전자전달 촉진에 기인하는 것으로 판단된다. 그러나, 60 s 동안 CuO 무전해 도금된 탄소 스펀지의 NO가스 감지 저항은 1.9%로 오히려 감소하였다. 이는 탄소 스펀지 표면에 CuO로 완전히 도금되어 NO 가스 흡착 능력이 떨어져 저항변화가 감소한 것으로 판단된다. 따라서, CuO가 도금된 탄소 스펀지는 빠르고 우수한 저항변화 특성을 가지고 있어 유용한 NO 가스 센서로 사용할 수 있으나, CuO가 탄소 스펀지 표면을 완전히 도금해서는 안 된다.

• Bulletin of the Korean Chemical Society
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• 제32권4호
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• pp.1331-1335
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• 2011

We report the results of the characterization of Cu oxide thin films deposited by radio frequency (r.f.) magnetron sputtering at different annealing temperatures. The deposited Cu oxide thin films were investigated by scanning electron microscopy, spectroscopic ellipsometry, X-ray diffraction, atomic force microscopy, Xray photoelectron spectroscopy, and contact angle measurements. The thickness of the films was about 180 nm and the monoclinic CuO phase was detected. The $CuO_2$ and $Cu(OH)_2$ phases were grown as amorphous phase and the ratio of the three phases were independent on the annealing temperature. The surface of Cu oxide films changed from hydrophilic to hydrophobic as the annealing temperature increased. This phenomenon is due to the increase of the surface roughness. The direct optical band gap was also obtained and laid in the range between 2.36 and 3.06 eV.

• 마이크로전자및패키징학회지
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• 제27권1호
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• pp.17-24
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• 2020

As an interconnect scaling faces a technical bottleneck, the device stacking technologies have been developed for miniaturization, low cost and high performance. To manufacture a stacked device structure, a vertical interconnect becomes a key process to enable signal and power integrities. Most bonding materials used in stacked structures are currently solder or Cu pillar with Sn cap, but copper is emerging as the most important bonding material due to fine-pitch patternability and high electrical performance. Copper bonding has advantages such as CMOS compatible process, high electrical and thermal conductivities, and excellent mechanical integrity, but it has major disadvantages of high bonding temperature, quick oxidation, and planarization requirement. There are many copper bonding processes such as dielectric bonding, copper direct bonding, copper-oxide hybrid bonding, copper-polymer hybrid bonding, etc.. As copper bonding evolves, copper-oxide hybrid bonding is considered as the most promising bonding process for vertically stacked device structure. This paper reviews current research trends of copper bonding focusing on the key process of Cu-SiO₂ hybrid bonding.

• 청정기술
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• 제8권3호
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• pp.111-117
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• 2002

동을 담지한 모더나이트를 이용하여 고정층 연속흐름 반응기에서 NO 분해와 CO에 의한 NO 환원을 실시하였다. NO 분해에서는 많은 동함량에서 $Cu^{\circ}/HM$이 CuO/HM보다 높은 분해 활성을 나타내었다. 이것은 $Cu^{\circ}/HM$과 CuO/HM에 존재하는 $Cu^{2+}$이온의 양과 CuO의 환원성 등의 차이에 관련된다고 보인다. NO 환원에서는 적은 동함량에서 Cuo/HM이 CuO/HM보다 높은 환원 활성을 나타내었다. 이것은 $Cu^{\circ}/HM$과 CuO/HM에 존재하는 CuO의 환원성과 입자 크기 등의 차이에 관련된다고 보인다.