• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.9
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• pp.80-85
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• 2011

In this paper, complex discharge type ozonizer with a screw type electrode has been designed and manufactured for environmental improvement using low power and high efficency ozoniazer. The complex discharge type ozonizer is equipped with three electrodes{central electrode(CE), internal electrode(IE) and external electrode(EE)}. Ozone of the complex discharge type ozonizer is generated by superposition of silent discharge and surface discharge in discharge space as a screw type CE and IE are respectively applied to AC high voltage of inverse-polarity has $180[^{\circ}]$ phase difference, EE is common electrode. In this time, when oxygen has been used as supplied gas, the maximum values of ozone concentration, ozone generation and ozone yield were obtained as 8,334[ppm], 3,249[mg/h] and 65.3[g/kwh].

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.3
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• pp.599-603
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• 2010

A point-mesh type corona system has been well used as a ionic wind blower. However this type corona system suffers from its lower ionic wind generation, because of its lower on-set and breakdown voltages of its very sharp needle point corona electrode. This means that the point corona electrode must act both as an effective ion-generator and a very higher electric field producer in the discharge airgap in order to generate higher ionic wind velocity. In this paper, a cylinder-mesh type discharge system as a ionic wind generator is proposed and investigated. The cylindrical corona electrode can produce many ions from its sharpened edge, and the corona on-set and breakdown voltages are very higher than those of the needle point corona electrode. As a result, this type cylindrical corona electrode might generate a higher ionic wind than the needle point corona electrode.

• The Journal of Information Technology
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• v.6 no.1
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• pp.65-70
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• 2003

In this papers, we proposed the new method in order to diagnosis partial discharge type of transformers. For wavelet transform, Daubechie's filter is used,, we can obtain wavelet coefficients which is used to extract featrue of statistical parameters(maximum value, average value, dispersion, skewness, kurtosis) about high frequency current signal per 3-electrode type(needle-plane electrode, IEC electrode and Void electrode). Also, these coefficients are used to identify signal of internal partial discharge in transformer. As a result, from compare of high frequency current signal amplitude and average value, we are obtained results of IEC electrode> Void electrode> Needle-Plane electrode. Otherwise, in case of skewness and kurtosis, we are obtained results of Void electrode> IEC electrode> Needle-Plane electrode. As improved method in order to diagnosis partial discharge type of transformers, we use neural network.

• Journal of the Korean Ceramic Society
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• v.52 no.1
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• pp.77-82
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• 2015

The effect of the electrode type on the dielectric and piezoelectric properties of $Pb(Mg_{1/3}Nb_{2/3})O_3-PbZrO_3-PbTiO_3$ (PMN-PZT) single crystals was investigated in an effort to improve their properties for various piezoelectric applications. First, three different types of PMN-PZT single crystals [PMN-PZT-A (piezoelectrically soft type; dielectric constant ~ 10,000), PMN-PZT-B (piezoelectrically soft type; phase-transition temperature between the rhombohedral and tetragonal phases ($T_{RT}$) ~ $145^{\circ}C$), PMN-PZT-C (piezoelectrically hard type; high mechanical quality factor ($Q_m$) ~ 1,000)] were fabricated using the solid-state single crystal growth (SSCG) method. Then, four different types of electrodes [sputtered Au, sputtered Cr/Au, sputtered Ti/Au, and fired Ag] were formed on the single crystals, and their dielectric and piezoelectric properties were measured. The single crystals with a sputtered Ti/Au electrode showed the highest dielectric and piezoelectric constants but the lowest coercive electric field ($E_C$). The single crystals with a fired Ag electrode showed the lowest dielectric and piezoelectric constants but the highest coercive electric field ($E_C$). This dependence on the type of electrode was most significant in the piezoelectrically hard PMN-PZT-C single crystals. However, the effects of the electrode type on the phase transition temperatures ($T_C$, $T_{RT}$) and dielectric loss were negligible. These results clearly demonstrate that it is important to select an appropriate electrode so as to maximize the dielectric and piezoelectric properties of single crystals in each type of piezoelectric application.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.3
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• pp.202-206
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• 2003

In this study, modified PbTi $O_3$ ceramics was manufactured to apply for 30MHz SMD type ceramic resonator with the variations of electrode weight. To investigate the effects of electrode weight on resonant characteristics of ceramic resonator using 3$^{rd}$ overtone thickness vibration mode, ceramic wafers for resonator were fabricated by evaporating electrode weights of 0.66, 1.765, 2.32, 3.87$\times$ 10$^{-4}$ g/c $m^2$ with silver, respectively. And then, SMD type ceramic resonators were fabricated with the size of 3.7$\times$3.1mm and electrode radius size of 0.77mm. With increasing electrode weight, resonant resistance was gradually decreased. At the electrode weight of 2.32$\times$10$_{-4}$ g/c $m^2$, mechanical quality factor( $Q_{mt3}$) and dynamic range(D.R) showed the maximum value of 2,152 and 49dB, respectively.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.5
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• pp.933-937
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• 2007

A point plate type nonthermal plasma reactor, with a grounded cylindrical third electrode which closely- encompasses the needle point, have been investigated with an emphasis on the role of the third electrode. It was found that the point plate airgap, with the grounded third electrode, had a switching characteristic on its I V characteristics for negative and positive discharges, which is very different from that of a conventional point plate airgap without a third electrode. The corona discharge and ozone generation characteristics of the plasma reactor with the grounded cylindrical third electrode, such as the corona onset voltage. the breakdown voltage. the corona current. and the amount of output ozone, were influenced significantly by the height of the third electrode. and these characteristics can be controlled by adjusting the height of the third electrode.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.894-899
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• 2002

In this papers, we proposed the new method in order to diagnosis partial discharge type of transformers. For wavelet transform, Daubechies filter is used, we can obtain wavelet coefficients which is used to extract feature of statistical parameters (maximum value, average value, dispersion, skewness, kurtosis) about high frequency current signal per 3-electrode type (needle-plane electrode, IEC electrode and Void electrode.). Also. these coefficients are used to identify Signal of internal partial discharge in transformer. As a result. from compare of high frequency current signal amplitude and average value. we are obtained results of IEC electrode> Void electrode> Needle-Plane electrode. otherwise. In case of skewness and kurtosis, we are obtained results of Void electrode> IEC electrode > Needle-Plane electrode. As Improved method in order to diagnosis partial discharge type of transformers, we use neural network.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.3
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• pp.310-315
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• 2009

This investigation was performed to study the characteristics of electricity and heat transfer that occur in the cylinder of electrode type humidifier during the process of water evaporation. Measurements were made to obtain the amount of water evaporation, the consumption of electric power, electrical conductivity, etc according to the materials and shapes of electrode. When the humidifier was in non-drain controlled mode, the number and amplitude of current cycle per minute increased gradually with the lapse of time, whereas for drain controlled mode, it decreased about 40[%] after draining water. It was found that for non-drain controlled mode, the thermal efficiency of humidifier which used SS400, STS316 and wire net electrode type was about 95~96[%] and it was 2~4[%] higher than that of drain controlled mode. Also, it was shown that the thermal efficiency of humidifier which used neighboring six-phase electrode balanced electrically was 4[%] higher than that of existing six-phase type.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.3
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• pp.583-587
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• 2007

Corona discharge and ozone generation characteristics of a slit dielectric barrier discharge type wire-plate plasma reactor with a third electrode have been investigated. When a third electrode is installed on a slit of the slit barrier, where an intense corona discharge occurs, it is found that a significantly increased ozone output could be obtained. This, however, indicates that the third electrode can activate the corona discharges both of the discharge wire and the slit of the slit barrier in the plasma reactor. As a result, a thin stainless wire, used as the third electrode has a strong effect to influence the corona discharge of the slit and corona wire, especially to the negative corona discharge. Higher amounts of the output ozone and ozone yield, about 1.27 and 1.29 times for the negative corona discharge, can be obtained with the third electrode, which reveals the effectiveness of the third electrode.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.1084-1087
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• 2002

The guard-ring type 3-terminal parallel plate electrodes proposed by ASTM D 150-81 and IEC 250 have been widely used for measurement of dielectric constants of solid dielectrics. However the method using this electrodes causes many uncertainty associated with the measurement errors of the diameter of the guarded electrode. the gap between guarded and guard-ring electrode. the distance of two active electrodes(the thickness of specimen), the roughness and contamination of surface of electrode and specimen. close adherence grade of electrode and specimen. In this paper. a new electrode system of cross capacitance type based on Thompson-Lampard theorem is designed and is employed for the measurement of dielectric constant. The results of simulation of guard-ring electrode and cross capacitance electrode using FEM program show that distance measurement between two electrodes in guard-ring electrode produces large uncertainty. on the other hand this effect in cross capacitance electrode is negligible. Furthermore. the air gap effects in the cross capacitance electrode is 5.6 times less sensitive than that in guard-ring electrode by assuming air gap of $50{\mu}m$.