• Journal of Electrochemical Science and Technology
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• v.11 no.4
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• pp.399-405
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• 2020

Hollow copper oxide/multi-walled carbon nanotubes (CuO/MWCNT) composites were fabricated via an optimized infiltration-reduction-oxidation method, which is more facile and easy to control. The crystalline structure and morphology were characterized by X-ray diffraction (XRD), and transmission electron microscopy (TEM). The as-prepared CuO/MWCNT composites deliver an initial capacity of 612.3 mAh·g^-1 and with 80% capacity retention (488.2 mAh·g^-1) after 100 cycles at a current rate of 0.2 A·g^-1. The enhanced electrochemical performance is ascribed to the better electrical conductivity of MWCNT, the hollow structure of CuO particles, and the flexible structure of the CuO/MWCNT composites.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.489-492
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• 2003

In this paper, we experimented on the deterioration process of power supply cords and analyzed the heating temperature of each part of those cords. We also analyzed the surface states, metallurgical structures surface structures and compositions of the wire melted by over-current. In the results of the analyses, the covering began to be deteriorated from the inside. The heating temperature of extension cord was higher than that of plug body. The dendrite structures appeared at the melted wire. By the SEM and EDS analyses, the dendrite structure showed the growth of copper oxide. We found out the characteristics of PVC insulated flexible cords by over-current from the above experiments and analyses. These results may be useful data in the analyses of deterioration causes of power supply cords.

• Bulletin of the Korean Chemical Society
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• v.18 no.9
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• pp.952-957
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• 1997

Modified polymeric composite electrodes having highly dispersed CuO particles through the electrode matrix were prepared for LCEC or flow injection analysis of carbohydrates. The composite electrodes were prepared by incorporating carbon black and highly dispersed copper oxide particles in polystyrene matrix cross-linked with divinylbenzene. The analytical characteristics of the electrodes for LCEC and flow injection analysis of carbohydrates were evaluated. Improved performance in LCEC and flow injection analysis of carbohydrates is demonstrated in terms of sensitivity, reproducibility, stability and surface renewability. It was possible to get improved performance of the electrodes as well as adaptability of the electrodes for practical applications by employing highly dispersed catalyst particles through the electrode matrix and robust polymeric electrode matrix.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.4
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• pp.361-365
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• 2003

A unipolar-type E-chuck was fabricated for the application of holding silicon wafers in the oxide etcher. For the fabrication of the unipolar ESC, core technologies such as coating of polyimide films and anodizing treatment of aluminum surface were developed. The polyimide films were prepared on thin coated copper substrates to minimize the plasma damage during the etch processing. Thin film heater technology was also developed for new type of E-chuck.

• Korean Journal of Materials Research
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• v.15 no.1
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• pp.1-5
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• 2005

Copper-based leadframe sheets were immersed in two kinds of hot alkaline solutions to form brown-oxide or black-oxide layer on the surface. The oxide-coated leadframe sheets were molded with epoxy molding compound (EMC). After post mold curing, the oxide-coated EMC-leadframe joints were machined to form sandwiched double-cantilever beam (SDCB) specimens. The SDCB specimens were used to measure the fracture toughness of the EMC/leadframe interfaces under quasi-Mode I loading conditions. Fracture surfaces were analyzed by various equipment to investigate failure path. The present paper deals with the failure path, and the cause of the failure path formation with an adhesion model will be treated in the succeeding paper.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.206.1-206.1
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• 2014

최근 전자 장비의 금속 전도성 패턴 제작에 있어서 직접적인 프린트가 가능한 프린팅 기술이 기존의 복잡한 photolithography 를 대체할 기술로 주목 받고 있다. 이와 함께 금속 전도성 패턴 제작에 사용되는 고가의 전도성 물질인 Ag ink 및 paste 를 저가의 Cu ink 및 paste 로 대체하기 위한 연구가 진행되고 있다. 하지만 일반적으로 copper 는 대기 중 에서 쉽게 산화되어 높은 저항을 야기시킨다. 따라서 Cu ink 또는 paste 를 제작할 때 copper nanoparticles 을 유기 용매에 분산하여 inert atmosphere에서 합성하거나 [1] copper ink 또는 paste 를 substrate 에 프린트하여 reduction atmosphere 에서 소성시킨다 [2]. 이번 연구에서 Cu paste 를 유리 기판에 screen printing 하여 혼합가스(질소 95%, 수소 5%)와 질소 가스 분위기에서 소성하여 Cu 전극의 소성 거동과 전기적 특성을 분석하였다. 4-point probe를 통해 소성된 Cu 전극의 저항을 측정하여 전도도를 조사하였으며 Thermal Gravimetric Analysis (TGA), Fourier Transform Infrared(FTIR)를 통해 소성된 Cu 전극의 유기물 분해가 전도도에 미치는 영향을 분석하고 Field Emission Scanning Electron Microscopy (FESEM)과 High Resolution Transmission Electron Microscopy (HRTEM)을 통해 Cu nanoparticles 의 grain growth가 전도도에 미치는 영향을 조사하였다.

• Journal of the Korean Ceramic Society
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• v.43 no.9 s.292
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• pp.544-551
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• 2006

The sealing technique between a glass tube and a copper heat pipe in an evacuated tube solar collector is studied. In this study two different sealing techniques, such as flame method and furnace firing, are examined. After the sealing of a copper to a glass, the oxidation state of the copper and its bonding morphology were examined by SEM and XRD. Its oxidation was retarded by coating of borate solution on the copper, and $Cu_2O(cuprite)$ turned into CuO(tenorite) with increase in a firing temperature and firing time. Porous structure was found in the oxide layer when CuO formed. The best sealing morphology was observed when the thickness of the oxidation layer was less than $20{\mu}m$. The sealing technique performed in a furnace was promising and the satisfactory result was obtained when the sample was fired at $950^{\circ}C$ for 5 min under $N_2$ atmosphere. Annealing procedure is recommended to remove the stress left at the bonding zone.

• Korean Journal of Materials Research
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• v.29 no.4
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• pp.228-232
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• 2019

Copper electroplating and electrode patterning using a screen printer are applied instead of lithography for heterostructure with intrinsic thin layer(HIT) silicon solar cells. Samples are patterned on an indium tin oxide(ITO) layer using polymer resist printing. After polymer resist patterning, a Ni seed layer is deposited by sputtering. A Cu electrode is electroplated in a Cu bath consisting of $Cu_2SO_4$ and $H_2SO_4$ at a current density of $10mA/cm^2$. Copper electroplating electrodes using a screen printer are successfully implemented to a line width of about $80{\mu}m$. The contact resistance of the copper electrode is $0.89m{\Omega}{\cdot}cm^2$, measured using the transmission line method(TLM), and the sheet resistance of the copper electrode and ITO are $1{\Omega}/{\square}$ and $40{\Omega}/{\square}$, respectively. In this paper, a screen printer is used to form a solar cell electrode pattern, and a copper electrode is formed by electroplating instead of using a silver electrode to fabricate an efficient solar cell electrode at low cost.

• Korean Journal of Materials Research
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• v.32 no.2
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• pp.80-84
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• 2022

Copper nanoparticles (CuNPs) are considered of great importance due to their high catalytic and antimicrobial activities. This study focuses on the preparation and characterization of CuNPs, and on their antibacterial/antifungal activities. A copper salt (copper sulfate pentahydrate) as precursor, starch as stabilizing agent, and ascorbic acid as reducing agent were used to fabricate CuNPs. The resulting product was characterized via different techniques such as X-ray diffractrometry (XRD), Fourier Transform Infrared (FTIR) spectroscopy, and Scanning electron microscopy (SEM) to confirm its characteristic properties. Employing the Scherrer formula, the mean crystallite sizes of copper (Cu) and cuprous oxide (Cu₂O) nanocrystals were found to be 29.21 and 25.33 nm, respectively, as measured from the main X-ray diffraction peaks. The functional groups present in the resulting CuNPs were confirmed by FTIR. In addition, the engineered CuNPs showed antibacterial and antifungal activity against tested pathogenic bacterial and fungal strains.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2005.04a
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• pp.28-29
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• 2005