• Applied Chemistry for Engineering
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• v.24 no.2
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• pp.196-200
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• 2013

We conducted investigation on polymeric binders for anti-static coating agent which can maintain stability under the high-voltaic condition. Various polyesters composed of polyethylene glycol (PEG) and polypropylene glycol (PPG) were synthesized and studied in term of the variation in the surface resistance of the film made from coating solution composed of a conductive polymer and these polyesters as a binder. We found that the surface resistance displayed $10^7{\sim}10^8{\Omega}/{\square}$ regardless of chemical composition of binders under the potential of 10 V. Whereas, the surface resistance surged to higher than $2{\times}10^{10}{\Omega}/{\square}$ when 1000 V was applied, rendering it improper for anti-static purpose. When 1,4 butanediol (BD) was incorporated into polyesters ([PEG]/[PPG]/[BD] = 25.0/67.5/7.5), the surface resistance showed $2.8{\times}10^9{\Omega}/{\square}$ under 1000 V, acceptable for anti-static application. These observations may indicate that the hydrophobic nature of BD makes a significant contribution to the surface resistance at a high positive potential.

• (The)Study of the Eastern Classic
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• no.70
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• pp.33-58
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• 2018

The purpose of this paper is to clarify the life and poetry of Dokshok Hwang Hyok. In Chapter 2, we looked at the life of Hwang Hyok. There are two characteristics in the life of Hwang Hyok. First, Hwang Hyok had excellent literary talent. Secondly, Hwang Hyok wrote in an attempt to surrender during the Japanese Invasion of Japan. That is why he lived a 21 year detained life. In Chapter 3, we looked at poetry based on the life of Hwang Hyok. The features of poetry are as follows. First, the image of Somu and reality of Tiger and Dhole go around. Hwang Hyok lived a confined life because of the Japanese Invasion of Korea. Because of that, Hwang Hyok recognized the Japanese invasion of the Imperial Japan as a world where Dhole and tigers travel around. It symbolized the image of Sommu that he did not surrender. Second, Changsha, is the world and Gulwon images. Changsha is Gulwon the space of self-destruction. Hwang Hyok likened his dark life to Gulwon dead. This is because Hwang Hyok's life is similar to Gulwon's life. In other words, Hwang Hyok was most appropriate to compare his tough life to Gulwon, who drowned in Myeoglasu.

• Composites Research
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• v.35 no.3
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• pp.127-133
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• 2022

Polypropylene (PP) has been received great attention as a next-generation high-voltage power cable insulation material that can replace cross-linked polyethylene (XLPE). However, the PP cannot be used alone as an insulation material because of its high elastic modulus and vulnerability to impact, and thus is mainly utilized as a form of a copolymer with rubber phases included in the polymerization step. In this paper, a soft PP-based blend was prepared through melt-mixing of impact PP, polyolefin elastomer, and propylene-ethylene random copolymer. The elastic modulus and impact strength of the blend could properly be decreased or increased, respectively, by introducing elastomeric phases. Furthermore, the blends showed a high storage modulus even at a temperature of 100℃ or higher at which the XLPE loses its mechanical properties. In addition, the blend was found to be effective in suppressing the space charge compared to the pristine PP as well as XLPE.

• (The)Study of the Eastern Classic
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• no.36
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• pp.105-134
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• 2009

Since long ago, "The Discourse of Confucius" has been considered as one of the must-read classical literatures in the world of art. The term Huì-shì-$h{\grave{o}}u-s{\grave{u}}$ (繪事後素) in this literature is not only known by the painter but is also known to anyone who discuss about pictures. However, there is a great diversity of interpretation between its meaning of "drawing a picture is done when its basis is ready" or "drawing a picture is done later when completed with white color". The method of drawing does not change much with time. Scholars usually consider professional paintings conventional and don't understand well the white characteristics of the painting technique. In any case, it is basic to deal with the basis before drawing but completing the picture, finishing with white is not so common. Paintings from ancient times are not so different from today's silk pictures. Because Huì-shì-$h{\grave{o}}u-s{\grave{u}}$(繪事後素) fostered the attainments being the basis of life and the artistic sense, it remains as the aesthetics to many artists. The interpretation of Huì-shì-$h{\grave{o}}u-s{\grave{u}}$(繪事後素) is related to the change with time in 'The theory of courtesy(禮論)' but this study focused purely from the artistic point of view.

• Journal of the Korean Institute of Intelligent Systems
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• v.5 no.4
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• pp.101-110
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• 1995

In this paper, a DC servo motor position control system based on acceleration control is proposed. The proposed control system consists of an acceleration controller and an auto-tuqing fuzzy PID controller. The auto-tuning fuzzy PID controller provides corrections for an acceleration reference to remove the effect of parametric uncertainties. And it comprises of the expert system which performs the automatic tuning of the PID controller parameters and the conventional PID controller. Expermental results demonstrate strate thi~tth e proposed overall control system has robust properties and good control performances with regard to unmeasurable disturbances and parameter variations. Therefore, the proposed control scheme enhances the applicability of an acceleration control approach and especially performs accurate position control under such an operating environment that model uncertainties exist and/or load, etc. change significantly.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.307-308
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• 2007

This work shows the experimental results obtained from ageing at a temperature of 100 C for 48, 70 and 312 h, although the application of AC electrical tension in samples and the measuring of current leakage are presented. The measurements in samples were carried out with samples prepared from the deformulated commercial materials and respectively reformulated into thin films. The obtained results showed the mechanisms of conduction of samples in low and high electric fields. It was also identified an electric tension transition showing that in low fields it prevails the Ohm's law conduction, and in high electric fields it prevails the conduction of space charge limited current (SCLC). These results can support the natural rubber formulation process having as their main objective the reducing of the mechanisms that occur under high conduction current in high electric fields, which leads the material to a dielectric breakdown. Raw Natural rubber in Brazil is extracted from rubber trees (Hevea brasiliensis) in farms in So Paulo State by using some new plantation technology in smaller spaces, with trees placed a few meters from each other. In the Amazon rain forest the rubber trees are found naturally and their spacing may be of hundreds of meters or even kilometers between them. It is necessary to research this raw material from different internationally standard clones to characterize dielectric and electric properties for industrial applications. Moreover, this natural material has a low commercial price when compared to the synthetic ones.

• (The)Study of the Eastern Classic
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• no.49
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• pp.137-160
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• 2012

This paper focuses on analyzing Eom Heun's grip on reality and attitudes through his literary works. He realized his time as a corrupted world that lack of morality. This actually was a criticism for the existing political force at that time, and he embodied it by using the image of wind, frost, mole cricket, ant, and so on. During that time, he tried to stick to his opinion on integrity. For that, he criticized men of the day who had an apathetic attitude. On the other hand, he praised pine and grass as an image of faith and fidelity. We may verify his world view by reading his literary works.

• Korean Journal of Oriental Medicine
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• v.1 no.1
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• pp.363-400
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• 1995

The electroacupuncture according to Voll(EAV) is a method of combining the fundamentals of classical acupuncture with the facilities of modern electronics for diagnostics and therapy. Classical acupuncture uses energy conducting lines called 'meridians' and acupuncture points situated along them. Dr. Voll is considered the founder of 'EAV' since he succeeded not only in finding a method of exact electric localization and in explaining the interelation between the acupuncture points and their individual organs, but he also succeeded in measuring the resistance of these points and in explaining the diagnostic meaning of the measured values. In the course of his research, Voll found numerous new measurement points and energy conducting vessels unknown to classical acupuncture, but indispensible for diagnosis of human organic functions. As a basis of modern research in meridian theory, I tried to compare EAV measurement point with classical acupuncture point.

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.120-121
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• 2000

Michelson 간섭계에 결맞음광을 입사시킬 때와 비고전광인 수 상태광을 입사시켰을 때의 위상감도에 대하여 이론적으로 계산하여 비교하였다. 수 상태광이 입사하는 경우라도 고전광인 결맞음광에서의 한계를 능가할 수 없음을 보였으며, 두 경우 모두 위상차의 불확정도 $\Delta$$ heta$는 1/(equation omitted) (N은 광자수)에 비례하였다. 또한 사용하는 광검출기의 양자효율에 따라 $\Delta$$\theta$가 어떤 영향을 받는지 분석하였다. (중략)

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1556-1557
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• 2011

변압기의 고체 절연이 열화 되거나 불순물 및 수분이 혼입되어 임계치 이상의 고전계가 인가되면 결합부분에서 부분방전이 발생한다. 현재 변압기에서 부분방전을 검출하기 위해서는 부싱탭을 이용하거나 전류센서, 초음파센서 등을 이용하여 부분방전을 검출하고 있지만 전기적인 부싱탭이나 전류센서를 이용한 검출 방법은 주변 잡음의 영향을 많이 받고 초음파법은 감도가 낮다는 단점을 가지고 있다. 이에, UHF 방식을 이용한 부분방전 검출 기술이 전력기기의 초기 고장진단을 발견하는 효과적인 방법으로 인식되고 있다. 최근에는 이러한 UHF 진단방식의 높은 감도, 외부노이즈에 대한 적은 영향, 온라인 측정의 가능성의 장점으로 전력용 변압기에도 적용되고 있다. 본 논문에서는 전력 변압기에서 PD 진단에 적합한 UHF 센서의 개발에 대해서 소개한다. 제안된 UHF 센서는 광대역(500 ~ 1,500MHz)에서 측정이 가능하며 감도가 우수하며 특정 대역에서 공진점을 가지는 다중 공진 모노폴 안테나 타입이다. 안테나 시뮬레이션 및 해석을 통해 유중 부분방전을 모의하여 감도 측정을 실시한 결과 제안된 UHF 센서가 전력용 변압기의 부분방전 측정에서 높은 감도를 나타냈으며, 기존 측정 방식의 단점을 보완할 수 있는 방안으로서 전자파를 이용한 부분방전 측정에 대한 기초연구를 실시하여 변압기 운전중에 전자파 측정에 의한 부분방전 감시가 가능한 것으로 나타났다.