• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.281-282
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• 2010

The microwave power supply is mainly composed of the cathode power supply supplying the beam voltage and beam current of the gyrotron and body power supply for the single depressed collector (SDC) operation, which requires the cathode voltage/current of 80 kV/24 A for the cathode and +24 kV for the body. This paper is describing the power supply system for the gyrotron of KSTAR.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.7 no.1
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• pp.75-80
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• 2008

This paper presents a new precision moving instrument for the displacement and direction control using the uni-morph type PZT actuator. The instrument is composed of the two-body and a link. The body has the uni-morph type PZT actuator, which make the vibration. Movement of simple moving instrument is generally analyzed by the theory of center-of-gravity moment. However the analysis of the instrument in this paper is focused the resonance of instrument. Resonance of the body is originated a uni-morph type PZT actuator that is vibrated by voltage and frequency. The basic performances of one body instrument are analyzed by the FEM analysis. And experiments are also performed to confirm the linear movement of the instrument and direction control. it is proper a voltage control than a frequency control for the direction changing. And Moving velocity is 0.032m/s.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.1
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• pp.124-131
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• 2008

Recently underground electrical power distribution is increased because people attach importance to aesthetics of the downtown areas. Lew-voltage handhole of underground distribution line for joint and branch point is mainly installed at the sidewalk. So, pedestrian can get a electric shock if fault is occurred in the low-voltage handhole. Furthermore the street was flooded by recently an unusual change in the weather. Fault is occurred in the low-voltage handhole that may create a shock hazard for the human body because a person's body resistance lower due to effect of water. This paper analyses causes of electric shock accidents and check results at the low-voltage handhole. At a result of analysis, the causes of electric shock accidents in domestic and foreign low-voltage handhole are same but environmental conditions of low-voltage handhole are different In the future, the analytical data can be applied to prevent the electric shock at the low-voltage handhole, and can be used to basic data for the improving installment of low-voltage handhole.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.78-81
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• 1997

The photocharge voltage technique is based on the measurement of a small electrical potential difference which appears on any solid body when subject to illumunation by a modulated laser light beam. This voltage is proportional to the induced change in the surface electrical charge and is nondestructively measured on various materials such as conductors, semicinductors and dielectrics. In this paper, photocharge voltage on conductors, semiconductors and dielectrics are measured nondestructively using a capacitative coupling. The test structures and the validity of this system to characterize the surface properties for soled materials are shown.

• Journal of the Korean Society of Safety
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• v.10 no.2
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• pp.77-83
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• 1995

An electrostatic reducer of a multi-pole high DC voltage applied type and a high frequency square wave voltage applied type have been studied to eliminate effectively and safely electrostatic charge on a dummy charged material. As a fundamental experiments, measurement were made on the decay time as a function of distance between electrostatic reducer and charged body, skewed angle of electrostatic reducer installed and wind speed of generated ions(＋ or －) by electrostatic reducer with high DC voltage and high frequency square wave voltage. Based oil the results above, a appropriate installation and method were produced as a trial for factory.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.7
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• pp.534-538
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• 2010

X-ray systems for medical treatment use noninvasive procedures. Being capable of locally inspecting the inside of the body, X-ray systems are routinely used for basic diagnosis. X-ray systems to be used for medical purposes were originally made with a gas filled tube inside an induction coil in the initial stages of development but with this approach it becomes difficult to take a satisfactory picture through thick body sections, non invasively. However continued development made it possible to take non-invasive pictures of breasts, blood vessels and other body parts through thick body sections. Recently, high-voltage X-ray generators of more compact size, increased generation efficiency, and sophisticated output control have become possible. All of these features are made possible by the use of a high-frequency output from an inverter and a fast switching semiconductor device. In this paper, we describe a new X-ray generator operating with a resonant inverter in order to reduce switching loss and high frequency noise. In addition, in order to identify the differences amongst types of rectification, we have compared output and the quality of X-ray pictures obtained with full-wave rectification and dual-voltage rectification methods.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.7
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• pp.1013-1018
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• 2014

This paper described the development of equalizing spacer for minimization of voltage drop according to DC feeder extension. Power consumption is increased as shorter interval of train driving time and transportation capacity increase in urban subway. Therefore we investigated voltage drop of catenary at a point in case of traction driving of a train in parallel to the DC power supply system. Based on it's result, equalizing spacer is designed and fabrication to minimize the voltage drop in accordance with the power supply line arranged in three rows, and then its performance was confirmed that the stress distribution of main body and the distributed load are satisfied through the body structure modeling.

• Journal of the Korean Society of Safety
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• v.5 no.1
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• pp.57-66
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• 1990

The purpose of this study is to investigate electrostatic charge condition and possibility of electrostatic hazards in case of putting on synthetic smocks and antistatic garments for the purpose of prevention of electrostatic hazards due to a human body electrical charge. It is shown in case of a synthetic smocks, electrostatic voltage by friction is about 2,900 (V), half life period is 12 second, and electrostatic charge is 1.4―1.8 ($\mu$ C). When putting on a synthetic smocks, electrostatic voltage is 2,500―2,800(V). When putting on a jumper of chemical fiber, electrostatic voltage is 8,000(V) . It is, therfore, possible to cause a electrostatic hazards. It is also shown in case of a antistatic garments, electrostatic voltage by friction is 87(V) ―280(V) (washing 90 times), half life period is 3―5 second, and electrostatic charge is 0.24―0.28($\mu$ C) which is much lower than 0.6($\mu$ C) limitation of fire and explosion occurance. When putting on a antistatic garments, electrostatic voltage is 10(V) ―125(V). In conclusion, it is shown when putting on a antistatic garments it is possible to prevent a electrostatic hazards such as fire or explosion due to human body, to prevent a destruction of semiconductor elements and capacity decline, and to prevent a misoperation of automation facilities and semiconductor electric and electronic products.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.764-765
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• 2010

The medical treatment X-ray machineries used in diagnosis of the human body is possible to diagnosis inside of the human body with the method of noninvasive so that it has shared a very important role in diagnosis from the medical institution. High voltage occurrence system which is most important in occurrence of X-ray has mainly been used the existing type of high voltage transformer, however it has a low efficiency of X-ray occurrence since it is a big and heavy, and a high ripple ratio of the direct current high voltage come to the X-ray tube. In order to solve this problem, the research has been advanced about the high voltage power supply system, and the inverter type of the high voltage occurrence system which occurs a high voltage by increasing the power frequency from about ten times to about hundred times with the inverter has currently used mainly. Also, the operation of tube voltage and tube current was controlled by using PWM method and the operation results were identified using an oscilloscope.

• Electrical & Electronic Materials
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• v.7 no.3
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• pp.225-230
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• 1994

In this paper, we have fabricated short channel MOSFETs with these parameters to verify the validity of process parameters extraction by DTC method. The experimental results of fabricated short channel devices according to the optimal process parameters demonstrate good device characteristics such as good drain current-voltage characteristics, low body effects and threshold voltage of$\leq$+-.1.0V, high punch through and breakdown voltage of$\leq$12V, low subthreshold swing(S.S) values of$\leq$105mV/decade.