• 한국재료학회지
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• 제26권1호
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• pp.17-21
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• 2016

Pt@Cu/C core-shell catalysts were successfully prepared by impregnation of a carbon support with copper precursor, followed by transmetallation between platinum and copper. The Pt@Cu/C core-shell catalysts retained a core of copper with a platinum surface. The prepared catalysts were used for hydrogen production through catalytic dehydrogenation of decalin for eventual application to an onboard hydrogen supply system. Pt@Cu/C core-shell catalysts were more efficient at producing hydrogen via decalin dehydrogenation than Pt/C catalysts containing the same amount of platinum. Supported core-shell catalysts utilized platinum highly efficiently, and accordingly, are lower-cost than existing platinum catalysts. The combination of impregnation and transmetallation is a promising approach for preparation of Pt@Cu/C core-shell catalysts.

• 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).

• 한국산학기술학회논문지
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• 제18권12호
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• pp.100-105
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• 2017

수질환경에서 구리이온을 검출하기 위하여 광섬유 센서의 구리 이온 감지 물질로 8-Hydroxyquinolin-2carboxaldehyde와 4-Aminoantipyrine으로 합성된 8-Hydroxyquinoline 합성유도체에 대해 광학적 반응 특성을 조사하였다. 실험은 광섬유를 이용한 측정시스템을 이용하여 수용액에 용해된 구리 이온의 농도에 대해 합성유도체에 의한 흡광도와 관계를 평가하기 위하여 수행되었다. 8-Hydroxyquinoline 합성유도체는 수질 환경에서 다양한 금속 이온들 중에서 구리 이온에 대해 노란색에서 붉은색으로 변화되는 높은 발색 현상을 나타냈으며 530 nm의 고유 흡광 파장을 보였다. 제작된 합성유도체의 Cu 이온에 대한 선택성을 평가하기 위하여 Hg 이온의 영향을 조사하였다. Cu와 Hg 이온의 다양한 농도 비 (Cu:Hg ratio 0.05부터 20까지)에서 흡광도를 측정한 결과, Cu 이온의 농도 증가에 따라 530nm에서 흡광도가 증가하는 경향을 보였다. 구리 이온의 고유 흡광 파장인 530 nm에서 합성 유도체에 의한 흡광도 세기는 구리 이온의 로그 농도에 선형으로 비례하였다. 따라서 8-Hydroxyquinoline합성유도체는 광섬유 센서의 구리 이온 감지 물질로 우수한 특성을 보임을 실험적으로 확인할 수 있었다.

• Advances in nano research
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• 제16권5호
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• pp.501-508
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• 2024

In this study, nanotoxicity tests were made by exposure of Artemia salina to copper (Cu 60-80 nm) and copper oxide (CuO 40 nm) nanoparticles (NPs) at different concentrations (0.2, 1, 5, 10, 25, and 50 mg/L). The LC₅₀ value of Cu (60-80 nm) NPs on the A. salina individuals at the beginning (0), 24^th, 48^th and 72^nd hours and elimination period was 52.37 mg/L while the LC₅₀ value of CuO (40 nm) NPs was 55.39 mg/L. The results of UV-Vis absorbance values showed that all statistical data revealed that maximum effect was observed between 24-30 hours and 25 ppm absorbance concentration was more effective. The multiple R, correlation coefficient (R2) and adjusted R2 values of Cu NP for the suitable Quadratic model were, respectively; 92.96 %, 86.42 % and 76.71 % while they are 98.31 %, 96.64 % and 94.25 % for CuO NP. Also, the data, was indicated effect size significantly changed based on the type and size of NP. Considering the microscope results, it was clearly noticed that A. salina organisms took the NPs in to their body. The accumulation in the gut of A. salina was observed and the images were taken with phase contrast microscope for both of NPs. The highest decrease for survival rates of A. salina individuals exposed to Cu NP was observed in the 10 ppm concentration (43.47 %) and in the 5 ppm concentration (46.20 %) for CuO NP. The results revealed that Cu and CuO NPS showed different toxic effects and that Cu NPs were more toxic than CuO.

• 한국재료학회지
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• 제28권10호
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• pp.601-609
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• 2018

To study the effects of graphite shape and the composite fabricating method on the mechanical properties of graphite/copper (Gr/Cu) composites, a copper composite using graphite flakes or graphite granules as reinforcing phases is fabricated using mechanical mixing or electroless plating method. The mechanical properties of the Gr/Cu composites are evaluated by compression tests, and the compressive strength and elongation of the Gr/Cu composites using graphite granules as a reinforcing phase are compared with those of Cu composites with graphite flakes as a reinforcing phase. The compressive yield strength or maximum strength of the Gr/Cu composites with graphite granules as a reinforcing phase is higher than that of the composites using graphite flakes as a reinforcing phase regardless of the alignment of graphite. The strength of the composite produced by the electroless plating method is higher than that of the composite material produced by the conventional mechanical mixing method regardless of the shape of the graphite. Using graphite granules as a reinforcing phase instead of graphite flakes improves the strength and elongation of the Gr/Cu composites in all directions, and reduces the difference in strength or elongation according to the direction.

• 동력기계공학회지
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• 제14권4호
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• pp.50-55
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• 2010

In order to investigate tribological effects of nano copper particles impregnated(CuN) on surface polytetrafluoroethylene(PTFE) on sealing wear and an experimental study was carried out to determine the wear behavior of copper nano-particles impregnation two kind thickness in super critical $CO_2$ liquid. Experimental results showed that the friction coefficients of CuN PTFE at the low sliding speed(0.44m/s) and the oil temperature ($60^{\circ}C$) were higher than that of virgin PTFE. And a thin nano copper particles impreganated thickness was formed on the surface in the PTFE and the specimen with this treatment has much better friction properties than the original one. Fortunately, at the high load(80 N) and the oil temperature, the friction coefficient of CuN PTFE was lower than that of virgin PTFE. This evidenced the load carrying capacity of CuN PTFE was much better than that of virgin PTFE under the high load condition(80 N) specially. Therefore, it can be concluded that the friction coefficient variation of CuN PTFE is very small but its wear rate decreases greatly with increase in sliding speed.

• 대한화학회지
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• 제37권10호
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• pp.888-894
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• 1993

아세토니트릴 용액 중에서 copper-1-(2-pyridylazo)-2-naphthol(Cu-PAN) 착물의 전기화학적 성질을 순환 전압전류법, 직류 폴라로그래프법, 정전위 전기분해법 및 UV-Vis 분광광도법으로 조사하였다. 아세토니트릴 용액 중에서 Cu-PAN 착물은 3개의 환원파를 보였다. 환원파의 환원전위는 각각 -1.27 V, -1.64 V 와 -2.08 V vs. Ag/AgNO$_3$(AN)였다. 각 환원단계에 관여하는 전자수는 일정전위 전기분해법으로 구하였으며, 전기분해한 전해 생성물의 UV-Vis Spectrum으로부터 전해 생성물을 확인하였다. 이상의 실험 결과로부터 아세토니트릴 용액 중에서 Cu-PAN 착물의 환원 반응기구를 제안하였다.

• 대한수의학회지
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• 제62권1호
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• pp.3.1-3.7
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• 2022

Disulfiram (DSF) is a marketed drug to treat patients with alcohol dependence by inhibiting aldehyde dehydrogenase. Over the last few decades, DSF has been shown to have anticancer effects through different mechanisms. Moreover, this effect can be elevated when used with copper (Cu). Subsequent studies have been conducted on various cancers, but few on lymphoma. This study investigated the anticancer effects of DSF on lymphoma and how this effect changed when treated with Cu. DSF synergistically decreased the metabolic activity of EL4 lymphoma cells when combined with Cu. At 1 µM of DSF alone, the metabolic activity of EL4 cells decreased by 49% compared to the control, whereas it decreased by 87% with a DSF + CuCl₂ treatment. Rhodamine 123 and 2',7'-dichlorofluorescein diacetate staining showed that DSF induced the reduction of the mitochondrial membrane potential and promoted the production of reactive oxygen species. In particular, the combined treatment of DSF + Cu induced cell death based on multiple assays, including annexin V-fluorescein isothiocyanate/propidium iodide staining. Overall, DSF has anticancer effects on lymphoma cells and exhibits synergistic effects when combined with Cu. This study provides some valuable information to broaden the use of DSF in clinics and basic research.

• Asian-Australasian Journal of Animal Sciences
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• 제23권1호
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• pp.82-89
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• 2010

An experiment was conducted to determine the influence of dietary inorganic (copper sulfate) and organic (copper proteinate) forms of copper and energy level on performance and nutrient utilization of broiler chickens. Two hundred day-old commercial Vencobb broiler chicks were purchased and randomly distributed to 20 cages of 10 birds each. These replicates were randomly assigned to one of five treatments in a (($2{\times}2$)+1) factorial arrangement. These two factors were sources of Cu ($CuSO_{4}$ vs. Cuproteinate) and dose of Cu supplements (200 mg and 400 mg/kg dietary dry matter) and the control (no supplemental Cu). After the starter period (up to 3 weeks), from d 22 onwards another factor i.e. energy at two levels (2,900 vs. 2,920 kcal/kg diet) was introduced with the previous factorial arrangements by subdividing each replicate into two equal parts, for two energy levels, without disturbing the dose and source of Cu supplement. Cu-salt supplementation linearly increased (p<0.01) live weight (LW), live weight gain (LWG) and feed conversion ratio (FCR) at 3 weeks, whereas cumulative feed intake (CFI) was unaffected (p>0.05). LWG and FCR were higher (p<0.01) in Cu-proteinate supplemented birds compared to $CuSO_{4}$ supplementation. A linear dose response (p<0.01) of Cu was found for the performance of broiler chickens. Birds having a higher energy level in the finisher stage increased (p<0.01) LWG and FCR. Cumulative feed intake was similar (p>0.05) across the groups up to the 5th week. Cu-proteinate increased performance of broiler chickens compared to $CuSO_{4}$. Dose of supplemental Cu-salt irrespective of source showed a linear response (p<0.01) for performance. Supplementation of Cu-proteinate increased metabolizability of DM (p<0.01), NFE (p<0.05), total carbohydrate (p<0.01) and OM (p<0.01) at the starter period. Increased dose of Cu-salt linearly increased (p<0.01) metabolizability of DM, CP, CF, NFE and OM. Higher energy level in the diet improved DM (p<0.05), EE (p<0.01), NFE (p = 0.01), total carbohydrate (p<0.01) and OM (p<0.01) metabolizability. Cu-proteinate supplementation showed better nutrient utilization compared to CuSO4. Dose of Cu linearly increased DM, CP, EE, NFE, total carbohydrate and OM metabolizability. CF metabolizability was unaffected (p>0.05) among the treatments. In conclusion, dietary supplementation of Cu-salt more than the requirement may improve performance and nutrient utilization in broiler chickens even with a high energy finisher diet. Cu-proteinate showed better performance and nutrient utilization compared to $CuSO_{4}$.

• 한국표면공학회지
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• 제42권6호
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• pp.280-286
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• 2009

In this study, the corrosion property of copper alloy tubes in seawater has been investigated. Three copper alloys of nominal composition Cu-20Zn-2Al(Al-Brass), Cu-30Ni(CN70/30) and Cu-10Ni(CN90/10) were considered. The samples were immersed in 3%NaCl flowing solution at $90^{\circ}C$ for 30, 50 and 80 days. Corrosion rate of copper alloy tubes in 3%NaCl flowing solution was investigated by weight-loss measurements and electrochemical test. The CN70/30 showed lowest corrosion rate among three copper alloy tubes. Because of passive films formation, corrosion rates of three types of copper tubes were decrease with time. Surface characteristics of copper alloy tubes were analyzed by optical micrograph(OM), scanning electronic microscopy (SEM), energy dispersive X-ray analysis(EDAX) and X-ray diffraction patterns(XRD). CN70/30 showed partly pitting problem on the surface owing to high Fe content, even though having high resistant against corrosion. Cracks appeared on the surface of CN90/10 and CN70/30 after more than 50 days immersion, which could be derived from high nickel contents.