• Bulletin of the Korean Chemical Society
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• 제31권8호
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• pp.2283-2288
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• 2010

Nanostructured copper compounds were grown by electrochemical anodization of copper foil in aqueous NaOH under varying conditions including electrolyte concentration, reaction temperature, current density, and reaction time. Their morphology and atomic composition were investigated by using SEM, TEM, XRD, EDS and XPS. At the conditions ([NaOH] = 1 M, $20^{\circ}C$, $2\;mA\;cm^{-2}$), wire-like orthorhombic $Cu(OH)_2$ nanobundles with an average width of 100 - 300 nm and length of $10\;{\mu}m$ were synthesized with the preferential [100] growth direction. Furthermore, when the concentration decreased to 0.5 M NaOH, the 1D nanobundle structure became narrower and longer without any change in compositions or crystalline structure. Side reaction pathways appeared to compete with the 1D nanostructure formation channels: the formation of CuO nanoleaves at $50^{\circ}C$ via the sequential dehydration of $Cu(OH)_2$, CuO/$Cu_2O$ aggregates in 4 M NaOH, and $Cu_2O$ nanoparticles and CuO nanosheets at lower current density.

• Journal of Magnetics
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• 제17권3호
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• pp.163-167
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• 2012

The effects on the ferromagnetism of the O or Zn defect in Cu-doped ZnO with the concentration of 2.77-8.33% have been investigated by the first-principles calculations. The Cu doping in ZnO was calculated to be a kind of p-type ferromagnetic half-metals. When the Zn vacancy exists in Cu-doped ZnO, the Cu magnetic moment increases, while for the O vacancy it is reduced. It is noticeable that the ferromagnetic state was originated from the hybridized O(2p)-Cu(3d)-O(2p) chain formed through the p-d coupling. The carrier-mediated ferromagnetism by nitrogen or fluorine does not depend on their concentration.

• 한국분말재료학회지
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• 제26권3호
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• pp.220-224
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• 2019

The aluminum (Al)/copper oxide (CuO) complex is known as the most promising material for thermite reactions, releasing a high heat and pressure through ignition or thermal heating. To improve the reaction rate and wettability for handling safety, nanosized primary particles are applied on Al/CuO composite for energetic materials in explosives or propellants. Herein, graphene oxide (GO) is adopted for the Al/CuO composites as the functional supporting materials, preventing a phase-separation between solvent and composites, leading to a significantly enhanced reactivity. The characterizations of Al/CuO decorated on GO(Al/CuO/GO) are performed through scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray spectroscopy mapping analysis. Moreover, the functional bridging between Al/CuO and GO is suggested by identifying the chemical bonding with GO in X-ray photoelectron spectroscopy analysis. The reactivity of Al/CuO/GO composites is evaluated by comparing the maximum pressure and rate of the pressure increase of Al/CuO and Al/CuO/GO. The composites with a specific concentration of GO (10 wt%) demonstrate a well-dispersed mixture in hexane solution without phase separation.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2007년도 추계학술대회 논문집
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• pp.75-76
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• 2007

ZnS:Cu,Cl phosphor was coated by solid-gel reaction with $SiO_2$ outside layer. The effect of $Cu^{2+}$-doping concentration has been investigated on the luminescence characteristics of ZnS:Cu,Cl blue-green phosphors for inorganic electro luminescent device. Also, SiO2 coated layers' effect on luminescence characteristics. Evaluation of luminescence characteristics dependent on the synthesis conditions is important to get high-performance phosphors properties. EL and PL properties such as luminescence intensity and chromaticity of ZnS:Cu,Cl phosphors synthesized with different concentration of activator, $Cu^{2+}$, were analysed separately

• Nano
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• 제13권10호
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• pp.1850122.1-1850122.6
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• 2018

Vertically aligned $WO_3$-CuO core-shell nanorod arrays for $NH_3$ sensing are prepared. The sensor is fabricated by preparing $WO_3$-CuO nanorod arrays directly on silicon wafer with interdigital Pt electrodes. The $WO_3$-CuO nanorod arrays are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The sensor based on the vertically aligned $WO_3$-CuO nanorod arrays exhibits ultrasensitive $NH_3$ detection, indicating p-type behavior. The optimum sensing temperature is found to be about $150^{\circ}C$. Both response and recovery time to $NH_3$ ranging from 50 ppm to 500 ppm are around 10-15 s. A possible $NH_3$ sensing mechanism of the vertically aligned hybrid nanorod arrays is proposed.

• 대한환경공학회지
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• 제31권12호
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• pp.1069-1074
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• 2009

본 연구에서는 CuO와 ZnO의 입자 크기가 옥수수의 성장과 토양 미생물 군집에 미치는 독성을 microcosm 실험을 통하여 살펴보았다. 나노 입자는 micro 입자에 비해 옥수수의 biomass를 약 30% 감소시켜 나노 입자가 옥수수의 성장을 저해하는 것으로 나타났다. 토양 미생물 활성 지표인 Dehydrogenase activity는 CuO 나노 입자에서는 낮게 나타났으나 ZnO 나노 입자에서는 높게 나타났다. Biolog test 결과, CuO 나노 입자와 ZnO micro 입자에서 토양 미생물 다양성이 감소하는 것으로 나타났다. 그러므로, metal oxide의 나노 입자가 micro 입자보다 항상 토양 미생물의 활성 및 다양성에 더 유해한 영향을 나타내는 것은 아니라고 판단된다.

• 한국자기학회지
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• 제17권2호
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• pp.99-102
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• 2007

The Cu oxide nano powders were synthesized by levitational gas condensation (LGC) method and their high heterogeneous catalytic effects of oxidation of 2,3,5-trimethyl-1,4-hydroquinone (TMHQ) and catalase activity were studied. The nano powders consist of mainly $Cu_2O$. The catalytic effect which was clarified by the oxidation of TMHQ and the activity of catalase, was found to depend on the amount of $Cu_2O$ phase and the particle size.

• Bulletin of the Korean Chemical Society
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• 제30권11호
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• pp.2559-2562
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• 2009

The lattice vibration and crystal structure of alkaline earth metal-substituted $RuSr_{1.9}A_{0.1}GdCu_{2}O_{8}$ (A = Ca, Sr, and Ba) have been investigated with micro-Raman spectroscopy. The present $RuSr_{1.9}A_{0.1}GdCu_{2}O_{8}$ materials show not only several weak Raman peaks corresponding to the vibrations of $O_{Cu}$ and $O_{Ru}$ but also strong characteristic phonon lines related to $O_{Sr}$ vibration mode. A comparison between the frequency of $O_{Sr}$ vibration and the bond distances of (Ru$O_{Sr}$) and (Cu‒$O_{Sr}$) in the present ruthenocuprates reveals that the vibration energy of $O_{Sr}$ is mainly dependent on the bond distance of (Ru‒$O_{Sr}$). The peak splitting of the $O_{Sr}$ phonon lines was observed for the unsubstituted $RuSr_{1.9}A_{0.1}GdCu_{2}O_{8}$, suggesting the existence of two different (Ru‒$O_{Sr}$) bond distances. Such a peak splitting caused by the appearance of low-energy shoulder reflects the presence of internal charge transfer pathway from the $RuO_2$ plane to the superconductive $CuO_2$ one. After the substitution of Sr with Ca or Ba, the low-energy shoulder peak of $O_{Sr}$ vibration becomes suppressed, underscoring the depression of internal charge transfer between the $RuO_2$ and $CuO_2$ planes. The weakened role of $RuO_2$ layer as charge reservoir in the $RuSr_{1.9}A_{0.1}GdCu_{2}O_{8}$8 (A = Ca, Ba) would be responsible for the depression of $T_c$ upon the Ca/Ba substitution.

• 공업화학
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• 제27권2호
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• pp.145-152
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• 2016

본 연구에서는 전기화학적 바이오센서의 포도당 감지능을 높이고자 금 나노 입자가 분산된 다중벽탄소나노튜브(multi-walled carbon nanotube, MWCNTs)에 CuO를 도입하였다. 금 나노 입자로 인하여 나노 클러스터(cluster) 형상을 갖는 CuO가 합성되었으며, 이는 포도당 감지능력에 매우 큰 영향을 나타내었다. 0.1 mole의 CuO가 합성되었을 때 CuO/Au@MWCNTs 나노복합재를 전극재료로서 바이오센서는 $504.1{\mu}A\;mM^{-1}cm^{-2}$으로 가장 높은 민감도를 보여주었으며, 이 값은 MWCNTs만을 전극으로 이용할 때보다 약 4배 정도 컸다. 또한, 0-10 mM의 긴 선형 구간(linear range)과 0.008 mM의 낮은 LoD (limit of detection) 값을 보여주었다. 이러한 실험 결과들은 CuO/Au@MWCNTs 나노복합재가 CuO를 이용한 다른 전기화학적 바이오센서보다 우수하다는 것을 입증하였으며, 이는 나노 클러스터 형상의 CuO가 포도당 감지에서 전기화학적 반응에 유리하기 때문으로 사료된다.

• 한국재료학회지
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• 제23권1호
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• pp.67-71
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• 2013

Porous $Al_2O_3$ dispersed with nano-sized Cu was fabricated by freeze-drying process and solution chemistry method using Cu-nitrate. To prepare porous $Al_2O_3$, camphene was used as the sublimable vehicle. Camphene slurries with $Al_2O_3$ content of 10 vol% were prepared by milling at $50^{\circ}C$ with a small amount of oligomeric polyester dispersant. Freezing of the slurry was done in a Teflon cylinder attached to a copper bottom plate cooled to $-25^{\circ}C$ while unidirectionally controlling the growth direction of the camphene. Pores were subsequently generated by sublimation of the camphene during drying in air for 48 h. The green body was sintered in a furnace at $1400^{\circ}C$ for 1 h. Cu particles were dispersed in porous $Al_2O_3$ by calcination and hydrogen reduction of Cu-nitrate. The sintered samples showed large pores with sizes of about $150{\mu}m$; these pores were aligned parallel to the camphene growth direction. Also, the internal walls of the large pores had relatively small pores due to the traces of camphene left between the concentrated $Al_2O_3$ particles on the internal wall. EDS analysis revealed that the Cu particles were mainly dispersed on the surfaces of the large pores. These results strongly suggest that porous $Al_2O_3$ with Cu dispersion can be successfully fabricated by freeze-drying and solution chemistry routes.