• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.11a
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• pp.375-380
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• 2004

This paper presents the basic quench protection idea for the HTS(High-Temperature Superconducting) cable. In Korea power system, the transfer capability of transmission line is limited by the voltage stability, and HTS cable could be one of the countermeasure to solve the transfer limit as its higher current capacity and lower impedance[1]. However, the quench characteristic of HTS cable makes HTS cable to loss its superconductivity, and therefore change the impedance of the line and power system operating condition dramatically. This pheonominum threats not only HTS cable safety but also power system security, therefore a proper protection scheme and security control counterplan have to be established before HTS cable implementation. In this paper, the quench characteristics of HTS cable for the fault current based on heat balance equation was established and a proper protection method by FCL(Fault Current Limiter) was suggested.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.50-53
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• 2004

BLDCM(Brushless D.C. Motor) is widely used for industrial application because of high efficiency and high power density. Especially, in servo system and home appliance, BLDCM is very useful due to high control performance and low acoustic noise. In this paper, 2.5HP rated BLDCM and its controller is developed for tread mill application. The prototype BLDCM has 4 poles rotor and 24 slots stator. Ferrite magnet was used as a rotor magnet because of the cost and temperature characteristic. For the stable operation of tread mill, current and temperature can be detected and treated by DSP. Thedesigned BLDCM and its controller is verified by the experimental results.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.884-885
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• 1998

The electrical characteristics of Stearic acid Langmuir-Blodgett(LB) films were investigated to develop the gas sensor using LB films. The deposition status of LB films were verified I-V characteristic which was increased with an applied voltage for the number of layers and decreased as increasing the distance of electrode. The conductivity of Stearic acid LB films was $10^{-8}[S/cm]$, which is typical of semiconductor. The conductivity of LB films were increased as the temperature was increased. The activation energy was about 1[eV].

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.465-468
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• 2001

An aerostatic stage has frictionless behavior, so it has a advantage of investigation into positioning characteristics. A one-dimensional aerostatic ceramic stage with ballscrew driven and laser scale feedback system is manufactured, aiming at investigating positioning characteristic of ultra-precision stage. We confirm, this ceramic aerostatic stage has a 10nm micro resolution, and can be reduced mean of position error by compensation of numeric control command. By means of analyzing relationship of position error and change of temperature, we build a on-line compensation algorithm of position error from the measured temperature data. So we can improve repeatability of ultra-precision stage up to 34%($0.095{\mu}$) of the normal condition.

• Journal of Korean Society for Quality Management
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• v.30 no.1
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• pp.61-73
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• 2002

The Quality Function Deployment(QFD) is a Quality Management technique to maximize customers' satisfaction by reflecting customer requirements into all business processes, including concept definition, product planning, parts planning, process planning, production planning, and sales planning. The basic concept of the QFD is to translate customers' requirements appropriately into engineering characteristics, into parts characteristics, into process characteristics, and into specific requirements and activities in production. In this study, we reviewed and analyzed the application process of the QFD to the development of A2 FATC (Full Automatic Temperature Controller), an automotive component developed and produced by company A. It has been reported that by applying the QFD to the development of A2 FATC, company A. achieved 34% improvement in control robustness quality characteristic, 27% improvement in deviation quality characteristic, and 30% improvement in overall quality characteristics.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.05a
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• pp.262-265
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• 2003

This Study is focused on the instrumenting Hybrid Rocket Motor of ACPL at Konkuk University and researching combustion instability by measuring regression rate versus oxidizer mass flux. In the result of experiment, test fire was moderate and we could acquire data of pressure, thrust, and temperature of combustion chamber. In the future, studying unsteady change of regression rate and pressure characteristic analysis of combustion chamber through hundreds of experiments should be performed. furthermore, researching characteristic velocity by taking a measurement of combustion temperature will be inevitable.

• Journal of IKEEE
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• v.17 no.3
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• pp.360-364
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• 2013

The maximum breakdown voltage's characteristic within the Super Junction MOSFET structure comes from N-Drift and P-Pillar's charge balance. By developing P-Pillar from Planar MOSFET, it was confirmed that the breakdown voltage is improved through charge balance, and by setting the gate voltage at 10V, the characteristic comparisons of Planar MOSFET and Super Junction MOSFET are shown in picture 6. The results show that it had the same breakdown voltage as Planar MOSFET which increased temperature resistance by 87.4% at $.019{\Omega}cm^2$ which shows that by the temperature resistance increasing, the power module's power dissipation improved.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.256-259
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• 2003

In this paper, a design of multi-layered BPF(bandpass filter) using LTCC(Low Temperature Co-fired Ceramic) process by a lumped-elements is proposed for SOP(system-on-a-chip) of wireless communication systems. The proposed BPF improved a characteristic of rejection band to build an attenuation pole caused by structurally adjacent co-inductance and coupling. The simulation data shows a bandwidth of 90MHz from a center frequency of 2.4GHz, a return loss of 27dB, an insertion loss of 3.2dB, and an attenuation of at least 20dBc at $f_0{\pm}250MHz$. Simulations have used serenade circuit simulation and HFSS EM simulation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.10
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• pp.1770-1775
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• 2010

An acceleration life test for rubber gasket of pole transformer was performed. The Arrhenius method was applied as an accelerated degradation test. The failure mode was considered as an elongation, and the failure mechanism is counted as a heat. It is found that both the current material(NBR: Nitrile Butadiene Rubber) and recommended alternative material(HNBR: Hydrogenated Nitrile Butadiene Rubber) have the same Weibull distribution as a life characteristic. For life expectation 95% reliability level of characteristic life is used at using temperature. The test results for NBR and HNBR are 7.7 years and 28.0 years on $50^{\circ}C$ of using temperature, respectively.

• Journal of Power System Engineering
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• v.4 no.1
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• pp.74-80
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• 2000

This present study was investigated effect of Ni contents on the high temperature strength characteristic in 9Cr ferritic heat-resistant steel added 1.7%W in place of Mo in order to restraint laves phase formation. Precipitation amount of carbide, number of particle per unit area and particle size of carbide were decreased with increase of Ni content. In the steels, carbides of $M_{23}C_6$ type was mainly precipitated, but laves phases could not precipitated. Tensile and yield strength, creep strength and creep rupture time was decreased, but elongation were increased due to decreasing of particle number per unite area and carbide amount precipitated with increase of Ni content.