• 한국정보통신학회논문지
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• 제12권6호
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• pp.1051-1055
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• 2008

ZnS는 전기적 에너지를 받으면 전자와 정공이 무수히 발생하며 이들이 평형상태로 갈 때 보다 높은 준위로 여기되면 빛이 생성될 수 있다. 박막 ELD는 탁월한 시각효과, 고체상태 및 제조의 용이성 등의 장점을 갖고 있으나 발광세기의 향상, 소모전력의 감소, 구동전압의 저하 등 해결되어야 할 문제점이 많이 남아있다. 이러한 문제점을 해결하기 위하여 보다 우수한 박막EL의 전계발광(EL)표시장치를 설계 제작하였다. 우수한 재료선택을 위하여 일본의 High purity사의 제품을 선택하였고, 이 제품이 Electron Beam으로 증착 시에 우수한 특성을 나타냈고, 휘도도 상용화된 800fL에 80% 수준으로 제작과정을 개선하여 더욱 우수한 결과를 얻을 수 있고 본 연구는 Yellow의 경우 650fL의 휘도를 얻었고, Green의 경우 350fL의 휘도를 얻었다. Electron Beam 제작용으로 자체 제작된 기판 홀더로 막을 제작한 결과 두께 균일도는 6% 내외 의 결과로 상당히 우수한 특성을 나타내었다.

• ETRI Journal
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• 제44권5호
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• pp.859-874
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• 2022

This paper presents a low-power and lightweight human body communication (HBC) receiver with an embedded dummy electrode for improved signal acquisition. The clock data recovery (CDR) circuit in the receiver operates with a low supply voltage and utilizes a clock phase inversion scheme. The receiver is equipped with a main electrode and dummy electrode that strengthen the capacitive-coupled signal at the receiver frontend. The receiver CDR circuit exploits a clock inversion scheme to allow 0.9-V operation while achieving a shorter lock time than at 3.3-V operation. In experiments, a receiver chip fabricated using 130-nm complementary metal-oxide-semiconductor technology was demonstrated to successfully receive the transmitted signal when the transmitter and receiver are placed separately on each hand of the user while consuming only 4.98 mW at a 0.9-V supply voltage.

• 비파괴검사학회지
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• 제24권5호
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• pp.487-493
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• 2004

본 연구는 고효율 비접촉 초음파 송수신이 가능한 미세가공 정전용량형 초음파 탐촉자(cMUT)를 개발하기 위한 기초연구로 수행되었다. cMUT의 주요 구성요소인 미세 진동 막의 거동-총진 주파수, 막 변위, 막 붕괴 변위, 막 붕괴전압-을 이론적인 해석과 유한요소해석을 이용하여 분석하였다. 진동 막의 두께와 크기, 희생층 두께, 전극의 두께와 크기 등과 같은 cMUT의 설계인자를 검토하였다. 분석결과 진동 막의 공진주파수는 진동 막의 두께가 증가함에 따라 증가하였으며 직경에 따라서는 감소하였다. 직류 바이어스 전압이 증가함에 따라 진동 막의 변위는 증가하였으며 진동 막의 붕괴전압을 분석하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.16-16
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• 2011

Plasmas in saline solutions receive considerable attention in recent years. How the operating parameters influence the plasma characteristics and how the electrode erosion occurs have been topics that require further study. In the first part of this talk, the effect of the frequency on the plasmas characteristics in saline solution driven by 50~1000 Hz AC power will be presented. Two distinct modes, namely bubble and jetting modes, are identified. The bubble mode occurs under low frequencies. In this mode, one mm-sized bubble is tightly attached to the electrode tip and oscillates with the applied voltage. With an increase in the frequency, it shows the jetting mode, in which many smaller bubbles are continuous formed and jetted away from the electrode surface. Multiple mechanisms that are potentially responsible to such a change in bubble dynamics have been proposed and the dominant mechanism is identified. From the Stark broadening of the hydrogen optical emission line, electron densities in both modes are estimated. It shows clearly that the driving frequency greatly influences the bubble dynamics, which in turn alters the plasma behavior. In the second part, the study of the erosion of a tungsten electrode immersed in saline solution under conditions suitable for bio-medical applications is presented. The electrode is immersed in 0.1 M saline solution and is positively or negatively biased using a DC power source up to 600 V. It is identified that when the electrode is positively biased, erosion by the surface electrolytic oxidation is the dominant mechanism with an applied voltage below 150 V. An increase in the applied voltage leads to the formation of the plasma and the damage by the plasma and the thermal effect becomes more prominent. The formation of the gas film at the electrode surface leads to the formation of the plasma and hinders the electrolytic erosion. In the negatively-biased electrode, no electrolytic oxidation is seen and the damage is mostly likely due to the plasma erosion and the thermal effect.

• 전력전자학회논문지
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• 제21권4호
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• pp.356-363
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• 2016

The design methodology of an adequate input voltage and magnetizing inductance to minimize reactive power is suggested to design a wireless power transfer (WPT) converter for high-power transfer efficiency. To increase the magnetizing inductance, the turn number of the WPT coil is increased, thus causing high parasitic resistance in the WPT coil. Moreover, the high coil resistance produces high conduction loss in the transfer and receive coils. Therefore, the analysis of conduction loss is used in the design of the WPT coil and the operating point of the WPT converter. To verify the proposed design methodology, the mathematical analysis of the conduction loss is presented by experimental results.

• BMB Reports
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• 제44권10호
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• pp.635-646
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• 2011

Due to its high external and low internal concentration the $Ca^{2+}$ ion is used ubiquitously as an intracellular signaling molecule, and a great many $Ca^{2+}$-sensing proteins have evolved to receive and propagate $Ca^{2+}$ signals. Among them are ion channel proteins, whose $Ca^{2+}$ sensitivity allows internal $Ca^{2+}$ to influence the electrical activity of cell membranes and to feedback-inhibit further $Ca^{2+}$ entry into the cytoplasm. In this review I will describe what is understood about the $Ca^{2+}$ sensing mechanisms of the three best studied classes of $Ca^{2+}$-sensitive ion channels: Large-conductance $Ca^{2+}$-activated $K^+$ channels, small-conductance $Ca^{2+}$-activated $K^+$ channels, and voltage-gated $Ca^{2+}$ channels. Great strides in mechanistic understanding have be made for each of these channel types in just the past few years.

• 전기학회논문지P
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• 제58권4호
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• pp.432-436
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• 2009

This paper is described that advanced study on network design of remote diagnosis system for power facilities of electric railway. In the field, it is very difficult for worker to diagnosis power facilities including catenary because workers should be maintenance on AC power supply. Therefore, to properly design on remote diagnosis system, we have searched the inside and outside of the country-related technology trends. Also we confirmed that required technologies to design interface technology required for the development of sensor devices and the USN network was designed in accordance with required skills. Throughout variety of requirements, we have development iRFS based ZA sensors and iRFM to receive data of sensor. Also CC2420 is applied as single-chip which used 2.4GHz IEEE802.15.4 compliant RF tranciver designed for low-power and low-voltage wireless applications for ZigBee communication.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.467-469
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• 2003

IEC(International Electrotechnical Commission) 62271-100 has been adopted for the design test of circuit breaker which is used as the main protecting device of power system. But, it is also necessary to separately receive the testing certificate in accordance with ANSI/IEEE standard for getting into the american market. Up to now, several domestic companies have completed the ANSI/IEEE testing in medium circuit breaker of distribution system, but they recently started the ANSI/IEEE testing in ultra high-voltage class of transmission and substation system. This paper introduces the testing techniques and its results for the making and breaking performance of 145kV, 40kA $SF_6$ gas circuit breaker which was firstly performed in KERI(Korea Electrotechnology Institute) by the ANSI/IEEE standard.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.230-231
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• 2012

This paper describes a gate driver that operates numerous semiconductor switch in the solide-state pulsed power modulator. the proposed gate driver is designed to receive both the isolated drive-power and the on/off pulse signals through the transformer. Moreover, the IGBT-switch can be quickly turned off by adding protection circuit. Therefore it protects the IGBT-switch from the arc condition that frequently occurs in high-voltage pulse application. To comprehend operating characteristic of each IGBT-switch in pulse output condition, the device consisting of a high efficiency soft-switching capacitor charger and two series stacking IGBT-switch is developed. Finally, the relability of the proposed gate driver and the device for its test are proved through PSpice simulation and experiments.

• 전력전자학회논문지
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• 제25권2호
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• pp.87-93
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• 2020

This study proposes a gate driver that operates semiconductor switches in the bipolar pulsed power modulator. The proposed gate driver was designed to receive isolated power and synchronized signals through the gate transformer. The gate circuit has a separate delay in the on-and-off operation to prevent a short circuit between the top and bottom switches of each leg. On the basis of the proposed gate circuit, a bipolar pulsed power modulator prototype with a 2.5 kV/100 A rating was developed. Finally, the bipolar pulsed power modulator was tested under resistive load and plasma reactor load conditions. It is verified that the proposed gate driver can be applied to a bipolar pulsed power modulator.