• Progress in Superconductivity
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• 제11권1호
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• pp.13-18
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• 2009

Partial discharge measurements in cryogenic dielectric materials of HTS transformer are very important because partial discharge was regarded as primary source for ageing and breakdown of cryogenic materials. But, partial discharge measurement techniques and its effects in low temperature high voltage environments were not suggested and there exist only a few reports on this research fields. Therefore, in order to implement reliable HTS transformers, partial discharge diagnosis techniques for cryogenic materials of HTS transformers were investigated using partial discharge (PD) pattern analysis methods. In this works, four different types of artificial defects including turn to turn insulation, free moving particle, void and protrusion, have been fabricated since it was commonly regarded that they might cause the sudden service failures of the power apparatus. For this purpose, these defects are installed into the dielectric materials in liquid nitrogen and experimental investigations have been carried out for the diagnosis of HTS transformer. And various PD patterns caused by the amount of quench of superconductors were analyzed. Throughout this works, the different PD patterns in cryogenic dielectric materials in liquid nitrogen, and PD measuring technique could be the fundamental steps to establish diagnosis technologies of HTS transformer for power applications.

• 제어로봇시스템학회논문지
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• 제10권11호
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• pp.991-999
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• 2004

Face robots capable of expressing their emotional status, can be adopted as an efficient tool for friendly communication between the human and the machine. In this paper, we present a face robot actuated with artificial muscle based on dielectric elastomer. By exploiting the properties of polymers, it is possible to actuate the covering skin, eyes as well as provide human-like expressivity without employing complicated mechanisms. The robot is driven by seven types of actuator modules such as eye, eyebrow, eyelid, brow, cheek, jaw and neck module corresponding to movements of facial muscles. Although they are only part of the whole set of facial motions, our approach is sufficient to generate six fundamental facial expressions such as surprise, fear, anger, disgust, sadness, and happiness. Each module communicates with the others via CAN communication protocol fur the desired emotional expressions, the facial motions are generated by combining the motions of each actuator module. A prototype of the robot has been developed and several experiments have been conducted to validate its feasibility.

• 대한전기학회논문지
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• 제41권7호
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• pp.802-808
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• 1992

To investigate degradation procedure and life time of the oxidized PE and the unoxidized PE, alternative voltage is applied to the CIGRE Method-II (CM-II) electrode system, which is loaded artificial void, and measures the distribution of partial discharging generation. From the results, the samples etched by oxidation had wide degradation area of dielectric strength. Furthermore, discharge starting voltage was shifted to low voltage, the discharge generation frequency was high and consequently, the quantity of mean charge becomes small. Also, life time of the oxdized sample is shortened according as the oxidation time is longer.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.334-337
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• 2003

In this paper. we introduce a novel actuation method based on dielectric elastomer. Along with basic principles of actuation using dielectric elastomer a new design of actuator is discussed. The proposed design has advantageous features in reduction in size, speed of response, ease and ruggedness of operation. Using the actuator. a three-degree-of-freedom actuator module is developed, which can provide up-down. and two rotational degree-of-freedom motion. In the application of the proposed actuation method, a micro-robot mimicking the motion of an inchworm is developed.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 1993년도 추계연구발표회 논문개요집
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• pp.96-97
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• 1993

• 한국산학기술학회논문지
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• 제13권5호
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• pp.2319-2324
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• 2012

본 논문에서는 가유전체 기판구조를 이용한 비대칭 브랜치 라인 커플러의 설계에 대하여 기술한다. 가유전체 기판구조에서는 주기적으로 다수의 비어홀들이 삽입되므로 등가적으로 유효유전율과 유효투자율이 증가하여, 여기에 전송선로를 구현할 경우 표준형 선로에 비하여 동일한 전기적 길이일 때 물리적 길이와 선폭이 감소하게 된다. 이런 특성을 이용하여 초고주파 회로들을 소형화하여 설계할 수 있는데, 본 논문에서는 2GHz대에서 동작하는 3:1 비대칭 브랜치 라인 커플러를 소형화하여 설계하는 것에 대하여 기술한다. 설계된 커플러는 표준형 전송선로를 이용하여 설계한 회로에 비하여 동일한 성능을 가지면서 약 53.4%의 크기를 갖는다. 비대칭 전력 분배 비율이 시뮬레이션과 측정 데이터에서 잘 일치하고 있으며, 측정된 손실도 불과 0.2dB 이내로 매우 적다.

• 한국산학기술학회논문지
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• 제10권7호
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• pp.1542-1548
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• 2009

본 논문에서는 기판 적층형 가유전체를 이용한 소형화된 윌킨슨 전력분배기 설계에 대하여 기술한다. 기판 적층형 가유전체 전송선로는 유효굴절률이 표준형보다 증가하여 전송선로의 선폭과 길이를 짧게 하는데, 이를 전자파회로에 응용하여 회로의 소형화 효과를 얻을 수 있다. 본 논문에서는 다수의 비어홀을 가진 기판 적층형 가유전체 구조를 효과적으로 시뮬레이션 하는 방법을 제안하고, 이를 회로 소형화에 응용한 사례를 보이기 위하여 기판 적층형가유전체를 이용한 소형화된 윌킨슨 전력분배기를 설계한다. 예로써 2GHz대의 윌킨슨 전력분배기를 설계, 측정한 결과가 제시되는데, SIAD 구조에 의한 유효 굴절률의 증가로 인하여 표준형 회로와 비교하여 동일한 전기적 특성을 유지하면서도 크기가 32% 감소되는 결과를 보인다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 춘계학술대회 논문집
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• pp.301-304
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• 1997

Effects of volatile impurities on deterioration characteristics of XLPE were investigated. Block type plate with needle-plane electrode and artificial void filled with $N_2$gas or humidity was subjected under high electric field. The dyed region by oxidation reaction around the artificial void filled with humidity was detected before tee initiation. Electrical tree was started from the tip of void filled with $N_2$gas earlier than humidity.

• 제어로봇시스템학회논문지
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• 제9권8호
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• pp.592-599
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• 2003

As one of the Principal modalities of human sensation, tactile feel is prerequisite for building wide variety of applications such as telemanipulation, virtual reality and medical engineering. A dynamic Braille display device based on a polymer actuator is presented. The actuator, often called artificial muscle actuator has advantageous features over the existing methods in terms of intrinsic softness, ease of fabrication, cost-effectiveness and miniaturization. The principles of actuation with dielectric elastomer is introduced, and necessary considerations on the design of a tactile display device are discussed. The design of the device is described in detail including the fabrication process and driving electronics. Also, preliminary results of experiments are given to evaluate its performance.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.1357-1358
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• 2013