• Proceedings of the KIEE Conference
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• 2008.09a
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• pp.207-210
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• 2008

In this paper, we researched the dielectric properties and voltage dependence on slice XLPE sheet from 22[kV] and 154[kV] power cable. We studied effects for impurities and water for semiconductor shield through a dielectric properties experiment to estimate performance of insulating materials in power cable. Capacitance and $tan{\delta}$ of 22[kV], 154[kV] were 53/43[pF] and $7.4{\times}10^{-4}$, $2.1510^{-4}$. In these results, the trend was increased with the increase of temperature. The tan6 of XLPE/semiconductor layer was increased as compared with that of XLPE. Dielectric properties reliability of tan6 was small. Also, To improve mean-life and reliability of power cable in this study, we have investigated chemical properties showing by changing the content of carbon black that is semiconductive additives for underground power transmission. Specimens were made of sheet form with the three of existing resins and the nine of specimens for measurement. Chemical properties of specimens was measured by FT-ATR (Fourier Transform Attenuated Total Reflectance). The condition of specimens was a solid sheet. We could observe functional group (C=O, carbonyl group) of specimens through FT-ATR. From these experimental result, the concentration of functional group (C=O) was high according to increasing the content of carbon black. We could know EEA was excellent more than other specimens from above experimental results.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.93-93
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• 2009

실리콘 태양전지의 효율 향상을 위한 노력의 일환으로 결정질 실리콘 웨이퍼 표면passivation 물질 중 Atomic Layer Deposition (ALD)을 이용하여 증착한 $Al_2O_3$ 박막에 대한 관심이 증가하고 있다. 본 연구에서는 $Al_2O_3$ 박막의 증착 전 실리콘 웨이퍼의 산화막 두께에 따른 passivation 효과에 대해서 연구하였다. 실리콘 산화막은 $HNO_3$ 용액을 사용하여 화학적으로 생성시켰으며 $HNO_3$ 용액과의 반응 시간을 조절하여 실리콘 산화막의 두께를 조절하였다. 실리콘 산화막 생성 후 ALD로 $Al_2O_3$ 박막을 증착하였으며 증착 후 $N_2$ 분위기에서 annealing 하였다. Annealing 후 passivation 효과는 Quasi-Steady-State Photo Conductance를 사용하여 minority carrier의 lifetime을 측정하였다. Capacitance-Voltage measurement, Transmission Electron Microscopy, Ellipsometry를 사용하여 실리콘 산화막의 두께에 따른 $Al_2O_3$ 박막의 passivation 효과를 분석하였다.

• Tribology and Lubricants
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• v.21 no.2
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• pp.71-76
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• 2005

This paper compares of mechanical tensile properties of 6 kinds of copper foil. The beam lead made with copper foil. Different from other package type such as plastic package, Chip Size Package has a reliability problem in beam lead rather than solder joint in board level. A new tensile loading system was developed using voice-coil actuator. The new tensile loading system has a load cell with maximum capacity of 20 N and a non-contact position measuring system based on the principle of capacitance micrometry with 0.1nm resolution for displacement measurement. Strain was calculated from the measured displacement using FE analysis. The comparison of mechanical properties helps designer of package to choose copper for ensuring reliability of beam lead in early stage of semiconductor development.

• Journal of Powder Materials
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• v.16 no.1
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• pp.37-42
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• 2009

In this study, the feasible test for the mechanical property characterization of $BaTiO_3$ ceramics and multi-layer ceramic capacitor(MLCC) was performed with nanoindentation technique. In case of $BaTiO_3$ ceramics, hardness and elastic modulus are dependent on the densification of specimen showing the highest hardness and elastic modulus values of 12.3 GPa and 155 GPa, respectively at $1260^{\circ}C$. In case of MLCC chip, hardness of dielectric layer was lower than that of margin region. The nanoindentation method could be useful tool for the measurement of mechanical property within $BaTiO_3$ dielectric layer of very thin thickness in high capacitance MLCC.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.320-321
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• 2006

In this work, impedance Spectroscopic analysis was applied to study the effect of plasma treatment on the surface of indium-tin oxide (ITO) anodes using $CF_4g$ as and to model the equivalent circuit for organic light emitting diodes (OLEDs) with the $CF_4$ plasma treatment of ITO surface at the anodes. This device with ITO/TPD/$Alq_3$/LiF/Al structure can be modeled as a simple combination of a resistor and a capacitor. The $CF_4$ plasma treatment on the surface of ITO shifts the vacuum level of the ITO as a result of which the barrier height for hole injection at the ITO/organic interface is reduced. The Impedance spectroscopy measurement of the devices with the $CF_4$ plasma treatment on the surface of ITO anodes shows change of values in parallel resistance ($R_p$) and parallel capacitance ($C_p$).

• Journal of the Korean Magnetics Society
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• v.4 no.2
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• pp.179-183
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• 1994

A high efficiency small electromagnet (22 mm air gap and $40{\times}25mm^{2}$ core's cross section) suitable for measuring magnetostriction and magnetic anisotropy was biult. The magnet could be minaturized by reducing the measuring space and time. The excitation current of the electromagnet was supplied for only a few second of measuring time. Cooling system of the electromagnet could be eliminated since the dissipation energy was very small. An 0.5 T magnetic field was generated with 180 W power consumption. The values of magnetostriction and magnetic anisotropy were measured with a very sensitive capacitance cell with resolution of $10^{-8}$ and 1 nJ. The torque was calibrated using a soft magnetic ribbon's shape anisotropy.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.242-250
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• 2008

Lining systems are used for two purpose in landfills : as covers to minimize leachate generation and surface water contamination by providing a barrier from precipitation and other percolating waters, and as containment liners to contain leachate and minimize its downward migration into underlying groundwater. So identifying leaks in landfill liners is an essential part of waste management. There are many leakage detection systems to monitor and seek leakage location, such as two electrode method, electrode grid method, diffusion hoses, capacitance sensors and tracers sensing cables. However, most of them can be applied in the new landfill construction sites because sensors must be installed prior to work. This paper presents a new type of leakage detection system, so called fence type electrode arrangement system, to monitor leakage and to seek leakage location in working landfill as well as new landfill. This system is based on the measurement of an electrical current flowing through leakage point. Series of laboratory tests are performed to investigate an availability of this system and this paper present some of these results.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.3
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• pp.311-317
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• 2014

In this paper, the flexible and reconfigurable frequency selective surface for C-band was designed using patch array and grid structure for radome and other curved surface applications. Frequency reconfigurability was obtained by varying the capacitance of varactor diode and flexibility is implemented by using flexible PCB. For the validity of the proposed structure, we fabricated the flexible and reconfigurable frequency selective structure and measured the frequency reconfigurability for different bias voltages and different curvature surfaces from the optimized design parameters. From the measurement results, we know that the proposed structure has the wideband reconfigurable frequency bandwidth of 6.05-7.08GHz. We can apply this proposed structure to the curved surface like as radome of aircraft or warship.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.3
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• pp.247-252
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• 2003

Aging and failure of motor insulation depend on the stresses imposed on it. The insulation life time depends on the severity of the stresses. The electrical aging by transient surge is very important to traction motor in EMU(electric multiple unit). This paper presents the insulation characteristics of stator coil by transient surge from inverter. There are several nondestructive tests available for checking the condition of motor insulation, the probable extent of aging, and the rate of which aging is taking place. So the insulation characteristics of stator coil were each analyzed by measurement of leakage current, dielectric loss(tan $\delta$), capacitance, polarization index(PI) and partial discharge. The method of diagnosis is able to analyze the aging condition and predict the life of the traction motor in EMU.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.67-69
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• 2006

Capacitance and loss values of pentacene MIS capacitors with different thicknesses are measured as a function of frequency for the modeling of the devices. The equivalent circuit for the ideal MIS capacitor is adopted to model the obtained admittance, so the values of $C_i,\;C_d,\;C_b$, and $R_b$ are determined for each pentacene thickness. In the loss curve, broader loss peaks are observed in measurement than the modeling results regardless of the pentacene thickness. By considering the effects of dispersive charge transport in bulk semiconductor, more accurate modeling results are obtained.