• Electrical & Electronic Materials
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• v.8 no.3
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• pp.357-361
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• 1995

An experiment on characteristics of nMOSFET's in the long stress condition with the maximum of the substrate current has been carried out in order to study on the degradation due to the hot-carrier effect. Based on the measured result of the threshold voltage, the damage is mostly due to the hole injection into the oxide. After long stress, it was shown that the drain current increased at low gate voltages and hence decreased at high gate voltages.

• Proceedings of the KSME Conference
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• 2000.11b
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• pp.124-129
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• 2000

The flow of liquid and vapor is investigated in trapezoidal grooves. The effect of variable shear stress along the interface of the liquid and vapor is studied for both co-current and counter-current flows. Velocity contours and results fur the friction are obtained for both trapezoidal grooves. An approximate relation that was previously utilized for the friction for the liquid was modified to obtain accurate agreement with the results for trapezoidal grooves.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.641-645
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• 1996

Ball screws are used in the feeding system for transmission of driving force. The friction effect between bed and table, which can affect in accuracyin one dimension feeding and describe the dynamic feeding error, could be simplified as a specific model through experiments. The experiments for dynamic feeding errors were performed om tje NC lathe eith a ball screw. The errors in feeding were measured with respect to the variances of feed, spindle speed and motor current for feeding. A rotary encoder and a current sensor were installed with NC lathe.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.274-277
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• 1997

Eddy current effect in a high speed rotor suspended by a mangnetic bearing is invstigated using electromagnetic field analysis technique. The non-zero conductivity model of a laminated rotor sleeve is proposed to concern electrical shorting of laminates due to rub, handling or press fit assembly,et al. As the rotating speed increase, the distibution of magnetic flux line is changed and the magnetic forces decrease remarkably. ANSYS Magnetics (version 5.3) is used for the magnetic field analysis.

• 한국초전도학회:학술대회논문집
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• v.14
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• pp.72-72
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• 2004

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.506-511
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• 1998

This paper gives and analytical expression of the average and rms currents of switching devices in volt-age-fed PWM inverters. It is shown that the device currents are represented by a function of the power factor of the load and the normalized output voltage of the inverter. The validity of the derived formulas is confirmed with simulation and experiment, showing that the modulation method has a minor effect on the characteristics of the device current.

• Proceedings of the KIEE Conference
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• 2008.10c
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• pp.139-141
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• 2008

In this paper, the authors study the boost converter as a DC-DC converter like a Power supply and describe the investigation result about the two phase with interleaved boost converter which has the same effect that the switching frequency of the solid-state-switch is two times. As a result, the ripple of the input current and output current is better improved.

• 한국초전도학회:학술대회논문집
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• 2008.08a
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• pp.89-89
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• 2008

• International Journal of Korean Welding Society
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• v.1 no.1
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• pp.13-16
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• 2001

High speed seam weldability of tin coated steels was investigated. Welding was performed by the laboratory wire seam welder that was equipped with process monitoring system Test results showed that increase in applied current and pressure reduced the total resistance across the welding electrodes. Lower and upper limits of welding current increased as the sheet thickness increased, while the acceptable welding condition range decreased. However, extremely low electrode pressure produced unstable welding condition range. The results also demonstrated that slower welding speeds widened the optimum welding heat input range.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.769-770
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• 1988

The Pockel's effect is well know as a voltage measurement method. This method is applicable to high voltage measurement equipments. We observe the Faraday rotation of the polarization plane in the current-induced magnetic field.