• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.464-469
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• 2017

This study evaluated the displacements of a Cu bar in the Y-direction and the relationship between swaging pressures and total contact forces to increase the productivity of the rotor core swaging process. Elastic-plastic numerical analyses of four different Cu bar shapes were performed with a constant swaging pressure to evaluate the displacements of the Cu bar in the Y-direction and the contact force distributions at the contact surfaces during the swaging process. Based on the numerical analysis results, the following conclusions were obtained. First, a simplified 2-dimensional cyclic symmetric analysis model was developed for the numerical analysis of the rotor core swaging process. Second, the final displacements of the Cu bar in the Y-direction were nearly the same as the change of the Cu bar size at a constant swaging pressure. Third, a linear relationship between the swaging pressures and the total contact forces, the so called resistance forces, was suggested.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2003.11a
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• pp.114-117
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• 2003

본 연구에서는 계산을 통해 나온 Sn-Ag-Cu 삼원계 공정점(Sn-3.7Ag-0.9Cu)을 바탕으로 그 근처의 응고경로가 다른 6가지 조성(Sn-4.6Ag-0.4Cu, Sn-4.9Ag-1.0Cu, Sn-3.9Ag-1.3Cu, Sn-2.2Ag-1.2Cu, Sn-2Ag-0.7Cu, Sn-2.7Ag-0.3Cu)에 대한 솔더합금의 미세조직을 관찰하였다. 응고경로는 $L\;\rightarrow\;L+Primary\;\rightarrow\;L+Primary+Secondary\;\rightarrow\;Ternary\;Eutectic+Primary+Secondary$로 되며 6가지 경우를 예상할 수 있다 솔더합금의 미세조직은 느린 냉각으로 인하여 빠른 냉각, 보통 냉각에 비해 상대적으로 커다란 $\beta-Sn$ dendrite를 보였고 $Ag_3Sn,\;Cu_6Sn_5$과는 다르게 $\beta-Sn$는 약 $30^{\circ}C$의 과냉(DSC분석)이 존재하게 되어 Sn-4.6Ag-0.4Cu의 경우에는 $Ag_3Sn$상이, Sn-2.2Ag-1.2Cu의 경우에는 $Cu_6Sn_5$가 과대성장을 하였다. 솔더의 기계적 특성을 살펴보고자 Cu 기판위에서 각 조성의 솔더볼을 솔더링한 후 다양한 냉각 속도를 적용하여 reflow 솔더링을 하고 솔더/기판 접합에 대한 전단 강도 시험을 실시했다. 냉각 속도가 빠를수록 $\beta-Sn$의 dendrite가 미세해져서 높은 전단 강도를 보였고 6가지 조성의 솔더볼중 공정조직 분율이 낮은 Sn-2Ag-0.7Cu 조성의 경우에서 낮은 전단 강도가 나타났다.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.1
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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 $CuSO_{4}$.

• Journal of the Korean Chemical Society
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• v.24 no.6
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• pp.421-425
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• 1980

The EPR absorption of furan compounds adsorbed on CuY zeolite was studied. With the adsorption of furan on CuY a new high field having a width of 8 gauss and g-factor of 2.002 appeared in EPR spectrum, while the original signal of Cu(Ⅱ) decreased. When 2-methylfuran was adsorbed on Cu(15)Y a new absorption band with a hyperfine structure appeared. With the increase of the degree of Cu(Ⅱ) ion exchange the resolution of the hyperfine structure became poor. The appearance of the new band was interpreted in terms of the formation of a charge transfer complex between Cu(Ⅱ) ion and the furan ring.

• Transactions on Electrical and Electronic Materials
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• v.10 no.5
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• pp.165-168
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• 2009

Transparent and conducting ITO/Cu/ITO multilayered films were deposited by magnetron sputtering on unheated polycarbonate (PC) substrates. The thickness of the Cu intermediate film was varied from 5 to 20 nm. Changes in the microstructure and optoelectrical properties of ITO/Cu/ITO films were investigated with respect to the thickness of the Cu intermediated layer. The optoelectrical properties of the films were significantly influenced by the thickness of the Cu interlayer. The sandwich structure of ITO 50 nm/Cu 5 nm/ITO 45 nm films had a sheet resistance of $36{\Omega}$/Sq. and an optical transmittance of 67% (contain substrate) at a wavelength of 550 nm, while the ITO 50 nm/Cu 20 nm/ITO 30 nm films had a sheet resistance of $70{\Omega}$/Sq. and an optical transmittance of 36%. The electrical and optical properties of ITO/Cu/ITO films were determined mainly by the Cu film properties. From the figure of merit, it is concluded that the ITO/Cu/ITO films with a 5 nm Cu interlayer showed the better performance in transparent conducting electrode applications than the conventional ITO films.

• Journal of the Korean Electrochemical Society
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• v.10 no.1
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• pp.14-19
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• 2007

The corrosion and passivation of copper was investigated with the copper rotating disk electrode(Cu-RDE) in borate buffer solution. It has been observed with the mixed potential theory that the corrosion potential for the rotation rate increase under the convective diffusion condition was increased. It was suggested that the chemical intermediates and product 13. the copper oxidation were $Cu(OH)_{ads},\;{Cu(OH)_2}^-,\;Cu_2O,\;Cu(OH)_2,\;and\;CuO$.

• Transactions on Electrical and Electronic Materials
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• v.1 no.3
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• pp.23-28
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• 2000

A block-oxide layer was formed on the surface of Cu-based leadframe by chamical oxidation method in order to enhance the adhesion strength between Cu-based leadframe and epoxy molding compound (EMC) Using sandwiched double cantilever beam (SDCB) specimens, the adesion strength was measured in terms of interfacial fracture toughness, G$\sub$IC//Results showed that the black-oxide layer was composed of two kinds of layers: pebble-like Cu$_2$O layer and acicular CuO layer, At the initial stage of oxidation the Cu$_2$O layer was preferentially formed and thickened up to around 200 nm whithin 1 minute of the oxidation time. Then the CuO layer started to from atop of the Cu$_2$O layer and thickened up to around 1300 nm until 20 minutes. As soon as the CuO layer formed, the thickness of Cu$_2$O layer began to reduce and finally reached to around 150 nm. The pre-cleaned and the Cu$_2$O coated leadframes showed almost no adhesion of EMC, however, as the CuO precipitates appeared and became continuous, G$\sub$IC/ increased up to around 80 J/㎡. Further oxidation raised G$\sub$IC/ up. to around 100 J/㎡.

• Applied Chemistry for Engineering
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• v.8 no.4
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• pp.645-652
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• 1997

Electrochemical characteristics and kinetic parameters of copper ion reduction were investigated with a platinum rotating disk electrode (RDE) in a diffusion controlled region. Reduction of Cu(II) in sulfate had one-step two-xelectron process, while the reduction of Cu(II) in chloride solution was involved two one-electron processes. The transfer coefficient of Cu(II) in sulfate solution was lowest, and the transfer coefficient of Cu(I) in halide solutions had the value of nearly one. In chloride solutions, electrodeposition rate of Cu(II) was about one hundred times faster than Cu(I). Diffusion coefficient increased in the order of Cu(II) in chloride solution, Cu(I) in the iodide, bromide, chloride solution, Cu(II) in sulfate solution. The calculated ionic radii and activation energy for diffusion decreased in the same order as above. Morphological study on the copper electrodeposition indicated that the electrode surface became rougher as both concentration and reduction potential increases, and the roughness of the surface was analyzed with UV/VIS spectrophotometer.

• Journal of Technologic Dentistry
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• v.20 no.1
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• pp.37-49
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• 1998

The specimens used were Ag-25 Pd-15 Cu ternary alloy and Au addition alloy. These alloys were melted and casted by induction electric furnace and centrifugal casting machine in Ar atmosphere. These specimens were solution treated for 2hr at $800^{\circ}C$ and were then quenched into iced water, and aged at $350{\sim}550^{\circ}C$ Age- hardening characteristics of the small Au-containing Ag-Pd-Cu dental alloys were investigated by means of hardness testing. X-ray diffraction and electron microscope observations, electrical resistance, ergy dispersed spectra and electron probe microanalysis. Principal results are as follows : Hardening occured in two stages, i.e., stage I in low temperature and stage II in high temperature regions, during continuous aging. The case of hardening in stage I was due to the formation of the $L1_0$ type face-centered tetragonal PdCu-ordered phase in the grain interior and hardening in stage I was affected by the Cu concentration. In stage II, decomposition of the ${\alpha}$ solid solution to a PdCu ordered phase($L1_0$ type) and an Ag-rich ${\alpha}2$ phase occurred and a discontinuous precipitation occurred at the grain boundary. From the electron microscope study, it was conclued that the cause of age-hardening in this alloy is the precipitation of the PdCu ordered phase, which has AuCu I type face-centered tetragonal structure. Precipetation procedure was ${\alpha}{\to}{\alpha}+{\alpha}_2+PdCu {\to}{\alpha}_1+{\alpha}_2+PdCu$ at Pd/Cu = 1.7 Ag-Pd-Cu alloy is more effective dental alloy as ageing treatment and is suitable to isothermal ageing at $450^{\circ}C$.

• Korean Journal of Materials Research
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• v.2 no.4
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• pp.241-247
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• 1992

The direct bonding of Cu to $Al_2O_3$, employing the $Cu-Cu_2$O eutectic skin melt, is investigated. The bonding force and interface structure of samples prepared by oxidation at $1015^{\circ}C$ in $1.5{\times}10^{-1}$torr followed by bonding at 107$5^{\circ}C$ under $10_{-3}$ torr vacuum have been studied using peeling test, SEM, EDS and XRD. It has been found that the optimal strength is obtained for 3 minutes of oxidation while the adhesion force is decreased with oxidation shorter or longer than 3 minutes. The rupture occured at alumina-eutectic interface. Fractured surface of $Al_2O_3$covered with $Cu_2$O nodules pulled out of the Cu indicates that bonding strength is governed by $Cu-Cu_2$O interface and not by $Cu_2$O-A$l_2O_3$interface. The bonding force is slightly increased with bonding time and the reaction phases of CuA$l_2O_4$and $CuAlO_2$are formed at interface during the bonding.