• KEPCO Journal on Electric Power and Energy
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• v.7 no.2
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• pp.237-240
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• 2021

Failure of a suspension clamp made of hot dip galvanized cast iron in 154kV transmission tower was investigated. Metallurgical analysis of a crack of the clamp was performed using a digital microscope, an optical microscope, and a scanning electron microscope. It was revealed that the crack surface was covered by continuous zinc layer. Distinctive casting skin was found underneath both the outer surface and crack surface. The result showed that pre-existing crack had been formed in the fabrication, and liquid metal embrittlement during hot dip galvanization may assist crack propagation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1351-1352
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.525-526
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• 2011

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.1
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• pp.1-6
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• 2009

The holding voltage of high-voltage devices under the snapback breakdown condition has been known to be much smaller than the operating voltage. Such characteristics cause high-voltage ICs to be susceptible to the transient latch-up failure in the practical system applications, especially when these devices are used as the ESD(ElectroStatic Discharge) power clamp circuit. A new latchup-free design of the ESD power clamp circuit with stacked-bipolar devices is proposed and successfully verified in a $0.35{\mu}m$ 3.3V/60V BCD(Bipolar-CMOS-DMOS) process to achieve the desired ESD level. The total holding voltage of the stacked-bipolar devices in the snapback breakdown condition can be larger than the operating voltage. Proposed power clamp operates safely because of the high holding voltage. From the measurement on the devices fabricated using a $0.35{\mu}m$ BCD Process, it was observed that the proposed ESD power clamp can provide 800% higher ESD robustness per silicon area as compared to the conventional clamps with a high-voltage diode.

• The Korean Journal of Physiology
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• v.18 no.1
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• pp.9-17
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• 1984

The second inward current $(i_{si})$ was studied by the two microelectrode voltage clamp technique in the sino-atrial node of the rabbit. The slow component $(i_{si,2})$ of the second inward current was sometimes identified and $i_{si}$ behaved as if it were a mixture of two currents. We analysed the $(i_{si,2})$ in relation to membrane potential and frequency of voltage clamp pulses. 1) Membrane was held at -40mV which was usually found to be zero current level. When depolarizing pulses were applied, the slow inward current $(i_{si})$ was activated. 2) It was shown that there are three categories of the $i_{si}$ activation by the low level of depolarizing clamp pulses. Moderately fast inward current with single component was developed in most cases in the presence of tetrodotoxin(TTX). But sometimes there was two separate components of $i_{si}$ activation in the peak level and the time course. Thirdly the only slow component of $i_{si}$ was found in rare cases. 3) The activation of $(i_{si,2})$ was dependent upon membrane potential. The $i_{si}$ shows two separate peaks during clamp depolarizations and higher clamp pulses lead to fusion of the peaks. 4) The $i_{si,2}$ activation showed that it decreased with repetitive clamp pulses and it was more evident in higher frequencies(2Hz)(negative staircase).

• Journal of Navigation and Port Research
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• v.29 no.8 s.104
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• pp.735-740
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• 2005

In this paper, we designed a wedge type rail-clamp which can protect container crane from sudden wind blast with constant clamping force regardless of the operating period. When we design wedge type rail clamp, it is important to determine an angle of wedge which prevent rotating of jaw and for smooth operation when wind blows. Therefore, this paper suggest a process to decide an angle of wedge within proper range obtained by experimental analysis as well as FEA of the wedge type rail clamp. A model with $6^{\circ}$ wedge angle is the most proper model to use in rail clamp bemuse it generated satisfactory clamping force and rotating angle underdesign specification.

• The Journal of the Convergence on Culture Technology
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• v.8 no.3
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• pp.265-270
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• 2022

The purpose of this study is to derive the damage weak part of the elastic rail fastening system for concrete tracks (System 300-1). In the concrete tracks, the elastic rail fastening system sticks the rail and the sleeper and reacts all the time when the train is running. Among the components of the rail fastening system, the resilience pad and tension clamp were fatigue members and were constantly deformed in response to compressive and uplift forces. In this study, the residual deformation characteristics of the tension clamp according to the period of use were analyzed using by specimens taken on site in the same section for 6, 11, and 16 years on the serviced urban transit. In addition, the damage mechanisms for each component were derived based on finite element analysis. As a result of the numerical analysis, the stress (strain) of each part of the tension clamp according to the external force from the applied clamping force was analyzed to derive the damaged weak part of the tension clamp.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.99-100
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.387-388
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.543-544
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• 2008