• Korean Journal of Materials Research
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• v.12 no.9
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• pp.740-746
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• 2002

In this study, the polycarbonate surface was treated by $O_2$/ Ar gases plasma for the enhancement of adhesion with Cu electrode. From the point of view of hydrophilicity and the functionality, the micro-roughness, new functional groups and oxygen content of the polycarbonate surface were increased by the $O_2$/ Ar gases plasma treatment. The Cu films deposited on the as-received polycarbonate were easily detached while, after the$ O_2$/ Ar gases plasma treatment the adhesive Cu films on polycarbonate could be obtained. These results can be explained that the polycarbonate had a hydrophilic surface with uniform micro-roughness and new functional groups by $O_2$/ Ar gases plasma treatment. Therefore,$O_2$/ Ar gases plasma treatment is a promising method for improvement of adhesion between polycarbonate and Cu electrode.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.290-291
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• 2006

We prepared the multilayer with Al doped ZnO (AZO)/Ag/AZO structure. The multilayer were deposited with various thickness of Ag layer on glass substrates at room temperature by using facing targets sputtering (FTS) method. To investigate the electrical, optical and structural properties, we used Hall Effect measurement system, four-point probes. UV-VIS spectrometer with a wavelength of 300 - 100nm, X-ray Diffractometer(XRD) and scanning electron microscopy (SEM). We obtained multilayer thin film with the low resistivity $5,9{\times}10^{-5}{\Omega}cm$ and the average transmittance of 86% m the visible range (400 - 800nm).

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.10a
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• pp.30.1-30.1
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• 2011

Silicon is one of useful materials in various industry such as semiconductor, solar cell, and secondary battery. The metallic silicon produces generally melting process for ingot type or chemical vapor deposition (CVD) for thin film type. However, these methods have disadvantages of high cost, complicated process, and consumption of much energy. Electrodeposition has been known as a powerful synthesis method for obtaining metallic species by relatively simple operation with current and voltage control. Unfortunately, the electrodeposition of the silicon is impossible in aqueous electrolyte solution due to its low oxidation-reduction equilibrium potential. Ionic liquids are simply defined as ionic melts with a melting point below $100^{\circ}C$. Characteristics of the ionic liquids are high ionic conductivities, low vapour pressures, chemical stability, and wide electrochemical windows. The ionic liquids enable the electrochemically active elements, such as silicon, titanium, and aluminum, to be reduced to their metallic states without vigorous hydrogen gas evolution. In this study, the electrodeposion of silicon has been investigated in ionic liquid of 1-butyl-3-methylpyrolidinium bis (trifluoromethylsulfonyl) imide ([bmpy]$Tf_2N$) saturated with $SiCl_4$ at room temperature. Also, the effect of electrode materials on the electrodeposition and morphological characteristics of the silicon electrodeposited were analyzed The silicon electrodeposited on gold substrate was composed of the metallic Si with single crystalline size between 100~200nm. The silicon content by XPS analysis was detected in 31.3 wt% and the others were oxygen, gold, and carbon. The oxygen was detected much in edge area of th electrode due to $SiO_2$ from a partial oxidation of the metallic Si.

• Current Optics and Photonics
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• v.1 no.1
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• pp.7-11
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• 2017

In this study, multilayered graphene was easily transferred to the target substrate in one step using thermal release tape. The transmittance of the transferred graphene according to the number of layers was measured using a spectrophotometer. The sheet resistance was measured using a four-point probe system. Graphene formed using this transfer method showed almost the same electrical and optical properties as that formed using the conventional poly (methyl methacrylate) transfer method. This method is suitable for the mass production of graphene because of the short process time and easy large-area transfer. In addition, multilayered graphene can be transferred on various substrates without wetting problem using the one-step dry transfer method. In this work, this easy transfer method was used for dielectric substrates such as glass, paper and polyethylene terephthalate, and a sheet resistance of ~240 ohm/sq was obtained with three-layer graphene. By fabricating organic solar cells, we verified the feasibility of using this method for optoelectronic devices.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.4
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• pp.117-128
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• 2016

Installation of earth grounding system is essential to ensure personnel safety and correct operation of electrical equipment. Earth parameters, especially, soil resistivity has to be determined in designing an efficient earth grounding system. The most common applied technique to measure soil resistance is Wenner four-point method. Implementation of this method is expensive, time consuming and cumbersome as large set of measurements with variable electrode spacing are required to obtain a one dimensional resistivity plot. It is advantageous to have a method which is of low cost and provides fast measurements. In this perspective, electrical resistance tomography (ERT) is applied to estimate subsurface resistivity profile. Electrical resistance tomograms characterize the soil resistivity distribution based on the measurements from electrodes placed in the region of interest. The nonlinear ill-posed inverse problem is solved using iterated Gauss-Newton method with Tikhonov regularization. Through extensive numerical simulations, it is found that ERT offers promising performance in estimating the three-dimensional soil resistivity distribution.

• Physical Therapy Korea
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• v.17 no.1
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• pp.69-76
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• 2010

Ischemia that causes stroke induces inflammation of brain cells and apoptosis and as a result, it influences much on the functional part of a man. The needle electrode electrical stimulation (NEES) that combines acupuncture of oriental medicine with electric therapy of western medicine relieves inflammation of cells and has effect on regrowth of nerve tissues. This study was conducted to verify the influence of NEES on the occurrence of c-Fos of cerebrum after applying NEES to the meridian point, Zusanli (ST 36) of a rats with induced ischemia. Global ischemia was induced by using ligation method on common carotid artery of male Sprague Dawley (SD) rats. The ligation was maintained for 5 minutes and then suture was removed for blood reperfusion. After inducing global ischemia, NEES was done to the left and right meridian points of Joksamri of a rat for 30 minutes after 12 hours, 24 hours, and 48 hours. The findings were as follows. 1. In the result of immunohistochemical method, the number of c-Fos immune response cells significantly decreased (P<.05) in NEES group than the control group (GI) that did not get NEES. 2. In the result of western blotting, the occurrence of c-Fos after 24 hours from the inducement of ischemia significantly decreased (P<.05) in NEES group than the control group (GI) that did not get NEES. Therefore, as the effect of NEES was shown highest after 24 hours from the ischemia, it is suspected that NEES would take important role in early treatment after cerebral stroke.

• Journal of the Korea Society of Computer and Information
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• v.17 no.9
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• pp.149-156
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• 2012

The Fabric Electrode was proposed for the effective production of the display based on electrowetting in this paper and designed the source driver of flexible display which could be driven by the electrowetting cell. The electrowetting cell matrix was implemented on the substrate(PET) by imprinting. The driver fabric, wetting electrode fabric and conductive fabric was placed horizontally and vertically in the groove between cell matrix and the electrowetting cell matrix can be driven by the cross-point as electric connection. The integration density of driver module is decreased because using the R/2R DAC module per channel in the conventional method. The proposed method could utilize the effective production process and reduce the production price of a display panel. The source driver which consume lower power and can increase the integration density because of reducing the number of driver device per channel was designed and evaluate the driver operation by the simulation using the VHDL programming in this paper.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.356-362
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• 2004

Using multi wrapped copper by polyimide film for HTS transformer, the breakdown and V-t characteristics of two type models for turn-to-turn, one is point contact model, the other is surface contact model, were investigated under ac and impulse voltage at 77 K. A material that is Polyimide film (Kapton) 0.025 mm thickness is used for multi wrapping of the electrode. Statistical analysis of the results using Weibull distribution to examine the wrapping number effects on V-t characteristics under at voltage as well as breakdown voltage under ac and impulse voltage in $LN_2$ was carried. Also, survival analysis was performed according to the Kaplan-Meier method. The breakdown voltages for surface contact model are lower than that of the point contact model, because the contact area of surface contact model is wider than that of point contact model. At the same time, the shape parameter of the point contact model is a little bit larger than the of the surface contact model. The time to breakdown tn is decreased as the applied voltage is increased, and the lifetime indices slightly are increased as the number of layers is increased. According to the increasing applied voltage and decreasing wrapping number, the survival probability is increased.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.203-207
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• 2007

Recently, ozone is utilized in various fields and its needs are expanding. In this paper, plate type ozonizer have been fabricated to investigate discharge parameter(input power, flow rate of supplied gas, electrode form, etc.) effect to discharge. And the conditions of discharge parameter have been investigated for optimum ozone generation. Ozone concentration is continuously increased with increasing input power for same discharge space, and ozone yield is also increased until maximum point after that it is saturated. Ozone concentration is inversely proportional to flow rate of supplied gas but ozone generation and ozone yield characteristics are improved.

• Journal of the Korean Applied Science and Technology
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• v.28 no.1
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• pp.48-56
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• 2011

In this study, we investigated the C-V diagrams and metal surface related to the electrochemistry characterization of metal(nickel, SUS-304). We determined electrochemical measurement by using cyclic voltammetry with a three-electrode system. A measuring range was reduced from initial potential to -1350mV, continuously oxidized to 1650 mV and measured to the initial point. The scan rate were 50, 100, 150, 200 and 250 mV/s. As a result, the C-V characterization of metal using N,N-dimethylacetamide and N,N-dimethylformamide inhibitors appeared irreversible process caused by the oxidation current from the cyclic voltammogram. After adding organic corrosion inhibitors, adsorption film constituted, and the passive phenomena happened. According to the results by cyclic voltammetry method, it was revealed that the addition of inhibitors containing amide functional group enhances the corrosion resistance properties.