• Journal of the Microelectronics and Packaging Society
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• v.9 no.1
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• pp.9-13
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• 2002

Recently, Organic electroluminescent devices (OELDs) have been demonstrated the medium sized full color display with effective multi-layer thin films. In this study, the multi-layer OELDs were prepared on the patterened ITO (indium tin oxide)/glass substrates by the vacuum thermal evaporation method. The low molecule compounds such as $Alq_3$(trim-(8-hydroxyquinoline)aluminum) and CTM (carrier transfer material) as the electron transport and injection layers as well as TPD (triphenyl-diamine) and CuPc (copper phthalocyanine) as the hole transport and injection layers were used. The luminance was rapidly increased above the threshold voltage of 10 V. The luminance and emission spectrum for the OELDs samples with $A1/CTM/Alq_3$/TPD/1TO structures were found to be 430 cd/$m^2$and 512 nm at 17 V showing green color emission. In contrast, the samples with $Li-A1/Alq_3$/TPD/CuPC/1TO multi-structures showed 508 nm in emission spectrum and 650 cd/$m^2$at 17 V in the luminance. The increment of luminance may be ascribed to the improved efficiency of recombination in the region of the emission layers by the deposition of CuPc as hole injection layer and the low work function of the Li-Al electrode compared to the Al electrode.

• Journal of Electrochemical Science and Technology
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• v.6 no.3
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• pp.106-110
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• 2015

This study investigates Cu(II) complexes of cyclam, propylene cross-bridged cyclam (PCB-cyclam), and propylene cross-bridged cyclam diacetate (PCB-TE2A) as homogeneous electrocatalysts for CO₂ reduction in comparison with Ni(II)-cyclam. It is found that Cu(II)-cyclam can catalyze CO₂ reduction at the potential close to its thermodynamic value (0.75 V vs. Ag/AgCl) in tris-HCl buffer (pH 8.45) on a glassy carbon electrode. Cu(II)-cyclam, however, suffers from severe demetalation due to the insufficient stability of Cu(I)-cyclam. Cu(II)-PCB-cyclam and Cu(II)-PCB-TE2A are revealed to exhibit much less demetalation behavior, but poor CO₂ reduction activities as well. The inferior electrocatalytic ability of Cu(II)-PCB-cyclam is ascribed to its redox potential that is too high for CO₂ reduction, and that of Cu(II)-PCB-TE2A to the steric hindrance preventing facile contact with CO₂ molecules. This study suggests that in addition to the redox potential and chemical stability, the stereochemical aspect has to be considered in designing efficient electrocatalysts for CO₂ reduction.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.421-421
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• 2008

Generally, the polymer thick-film resistors for embedded organic or hybrid substrate are patterned by screen printing so that the accuracy of resistor pattern is not good and the tolerance of resistance is too high(${\pm}$20~30%). To reform these demerits, a method using Fodel$^{(R)}$ technology, which is the patterning method using a photosensitive resin to be developable by aqueous alkali-solution as a base polymer for thick-film pastes, was recently incorporated for the patterning of thermosetting thick-film resistor paste. Alkali-solution developable photosensitive resin system has a merit that the precise patterns can be obtained by UV exposure and aqueous development, so the essential point is to get the composition similar to PSR(photo solder resist) used for PCB process. In present research, we made the photopatternable resistor pastes using 8 kinds of epoxy acrylates and a conductive carbonblack (CDX-7055 Ultra), evaluated their developing performance, and then measured the resistance after final curing. To become developable by alkali-solution, epoxy acrylate oligomers with carboxyl group were prepared. Test coupons were fabricated by patterning copper foil on FR-4 CCL board, plating Ni/Au on the patterned copper electrode, applying the resistor paste on the board, exposing the applied paste to UV through Cr mask with resistor patterns, developing the exposed paste with aqueous alkali-solution (1wt% $Na_2CO_3$), drying the patterned paste at $80^{\circ}C$ oven, and then curing it at $200^{\circ}C$ during 1 hour. As a result, some test compositions couldn't be developed according to the kind of oligomer and, in the developed compositions, the measured resistance showed different results depending on the paste compositions though they had the same amount of carbonblack.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.1
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• pp.75-80
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• 2015

After some period of time, the marine traffic facilities find problems caused by shellfish adhered to inside and inlet of the water column. Therefore, single-channel AFS(Anti-Fouling System) has been applied in order to minimize the deposition of shellfish. However, imbalance phenomenon of ionization of copper electrodes that are used for single-channel AFS appeared. This problem resulted in frequent replacement of anode. In this paper, multi-channel current control system has been developed, as well as the related hardware has been designed and fabricated. Further, experimental study has been undertaken to compare the application of single and multi- channel AFS. Through the sea experiments, it was possible to confirm that the copper electrode used for multi-channel AFS is uniformly ionized.

• Korean Journal of Materials Research
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• v.25 no.4
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• pp.202-208
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• 2015

Alumina dispersion strengthening copper(ADSC) alloy has great potential for use in many industrial applications such as contact supports, frictional break parts, electrode materials for lead wires, and spot welding with relatively high strength and good conductivity. In this study, we investigated the oxidation behavior of ADSC alloys. These alloys were fabricated in forms of plate and round type samples by surface oxidation reaction using Cu-0.8Al, Cu-0.4Al-0.4Ti, and Cu-0.6Al-0.4Ti(wt%) alloys. The alloys were oxidized at $980^{\circ}C$ for 1 h, 2 h, and 4 h in ambient atmosphere. The microstructure was observed with an optical microscope(OM) and a scanning electron microscope(SEM) equipped with energy-dispersive X-ray spectroscopy(EDS). Characterization of alumina was carried out using a 200 kV field-emission transmission electron microscope(TEM). As a result, various oxides including Ti were formed in the oxidation layer, in addition to ${\gamma}$-alumina. The thickness of the oxidation layer increased with Ti addition to the Cu-Al alloy and with the oxidation time. The corrected diffusion equation for the plate and round type samples showed different oxidation layer thickness under the same conditions. Diffusion length of the round type specimen had a value higher than that of its plate counterpart because the oxygen concentration per unit area of the round type specimen was higher than that of the plate type specimen at the same diffusion depth.

• Journal of the Korean Chemical Society
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• v.38 no.2
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• pp.146-150
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• 1994

The simultaneous determination of Zn, Cd, Pb and Cu in 1.000%(w/v) tungsten matrix by differential pulse anodic stripping voltammetry at a hanging mercury drop electrode has been studied. Tartaric acid(pH=5.00) was used as a supporting electrolyte. Optimum analytical conditions were found that the deposition potential was -1.2 volt(vs. Ag/AgCl), the deposition time was 3 minutes. The linear concentration range of all trace metal ions in 1.000%(w/v) tungsten matrix were 10 to 50 ppb. And the detection limit(3${\sigma}$) of zinc, cadmium, lead and copper were 1.25, 1.02, 1.69, and 1.02 ppb respectively. This method was superior to the ICP-AES method which detection limits(3${\sigma}$) in 1.000%(w/v) tungsten matrix were 8.0, 5.0, 120 and 5 ppb respectively.

• Journal of Electrical Engineering and Technology
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• v.10 no.5
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• pp.2205-2210
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• 2015

Experimental studies have been carried out to study the principle operation of the conductive type wire-mesh tomography sensor and analyse the wire-mesh tomography sensor for the liquid/gas two-phase flow interface and void fraction distribution in a process column. The measurement of the two-phase flows in the process column is based on the cross-sectional local instantaneous conductivity. The sensor consists of two planes of parallel electrode wires with 16 electrodes each and was placed orthogonally with each plane. The sensor electrode wires were made of tinned copper wire with an outer diameter of 0.91 mm which stretched over the sensor fixture. Therefore, this result in the mesh grid size with 5.53×5.53mm². The wire-mesh sensor was tested in a horizontal liquid/gas two-phase flows process column with nominal diameter of 95.6 mm and the sampling frequency of 5882.3529 Hz. The tomogram results show that the wire-mesh tomography provides significant results to represent the void fraction distribution in the process column and estimation error was found in the liquid/gas interface level

• Applied Biological Chemistry
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• v.28 no.1
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• pp.8-12
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• 1985

For measuring calcium content during the manufacturing process of Tofu, conductometric electrodes were made with the copper plate, and the results were compared with chemical analysis methods. Three types of plate material (I, II, III) for electrode were tested to apply for measuring $CaCl_2$ content in solution, drained solution from Tofu and in agar-agar gel ana Tofu. Empirical linear correlation equations between conductivity (Y, mho) and calcium content (C, Mole $\bar{C}$, mg% wet basis) were obtained for the quick estimation of calcium content during Tofu processings. Equations with plate II type electrode were Y=0.6364C+0.0775 for drained solution with r=0.99, and $Y=7.1503{\times}10^{-5}\bar{C}-2.9895{\times}10^{-3}$ for Tofu with r=0.91,respectively.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.2
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• pp.95-101
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• 2003

In this paper, partial discharges(PDs), lift off and breakdown voltage were measured when metal particles existed in a model GIS coated with epoxy resin on its bottom electrode, and the measured results were analyzed after comparing with the model DIS not coated. In order to presume the various fault case in GIS, we measured the experimental values with changing some experimental factors, such as the mixture ratio of SF$\_$6//N$_2$, the pressure of the gases, the kinds and diameter of the metal particles, and the coating thickness of the epoxy resin. As a result, the PDIV increased with the thickness of the epoxy resin, while the magnitude of PDs decreased at the same condition. The lift off voltages of steel alloy particles were higher than that of copper particles, and increased wit diameter of particles. Futhermore, the lift off voltages in the case of the electrode coated with epoxy resin were higher than that in the case of the uncoated one. In addition, the thicker the thickness of the epoxy resin was, the higher the breakdown voltage were. Thus, it was confirmed that the GIS coated with epoxy resin on its inner surface could be improved in insulation performance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.758-760
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• 2007

Organic field-effect transistors (OFETs) are of interest for use in widely area electronic applications. We fabricated a copper phthalocyanine (CuPc) based field-effect transistor with different metal electrode. So we need the effect of the substituent group attached to the phthalocyanine on the surface potential was investigated by Kelvin probe method with varying temperature of the substrate. We were obtained the positive shift of the surface potential for CuPc thin film. We observed the electron displacement at the interface between Au electrode and CuPc layer and we were confirmed by the surface potential measurement.