• 대한기관식도과학회:학술대회논문집
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• 대한기관식도과학회 1979년도 제13차 학술대회 연제순서 및 초록
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• pp.3.2-3
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• 1979

만성중이염에서 나타나는 감각신경성난청은 고음역난청이며 이는 중이염의 흔하고 또 중요한 합병증이기도 하다. 자자들은 과거 1년간 경험한 233예의 만성중이염수술례중 187예를 대상으로 수술전 청력소견상 골도치에 대하여 임상소견을 중심으로 통계학적 분석을 하였으며 또한 기니픽의 자연발생한 만성화농성중이염의 병리조직학적소견을 관찰하여 보고하는 바이다. 대상의 평균연령은 24.5재이었다. 1) 일측성만성중이염에서 건측과 환측의 골도치를 이원배치산분석법으로 비교한 결과 건측과 환측간 및 각 주파수간에 유의한 차이가 있었으며 그들 사이에 유의한 상호작용이 인정되었다. 특히 2KHz와 4KHz 사이에서 유의한 차이(P<0.01)가 있었다. 2) 상병기간에 따른 일원배치분산 분석에서는 11∼15연군과 15∼20년군 사이를 제외한 각군간에서 유의한 차이(P<0.05)가 있었다. 3) 등골손상유무에 따른 분석에서 골도치를 t 검정으로 비교한 결과 각 주파수에서 모두 유의한 차이(p<0.01)가 있었으며, 등골손상의 주파수에 대한 영향을 일원배치분산분석법으로 비교한 결과 250Hz와 500Hz 사이 및 2KHz와 4KHz 사이에서 유의한 차이(P<0.05)가 있었다. 4) 정원창폐쇄유무에 따른 골도변화를 t 검정으로 비교한 결과 각 주파수에서 모두 유의한 차이(p<0.01)가 있었다. 정원창폐쇄의 각 주파수에 대한 효과를 일원배치분산분석법으로 비교한 결과 250Hz와 500Hz사이 및 2KHz와 4KHz사이에서 유의한 차이(P<0.01)가 있었다. 5) 진주종유무에 따른 골도변화를 t 검정으로 비교한 결과 진주종성중이염에서는 2KHz와 4KHz에서만 유의한 차이(p<0.01)를 보였으나 수도평균치에서는 유의한 차이를 보이지 않았다. 6) 기니픽의 만성화농성중이염의 측두골 병리조직학적 병변의 검경상 만성염증성병소의 내이, 특히 와우침입로로서의 정원창의 병변이 뚜렷하여 이로 인한 외임파강내의 염증성병변이 뚜렷이 나타나 있으며 와우관의 특히 기저회전에서의 유모세포의 손실이 심한 것으로 보아 중이염으로 인한 골도의 고음역에서의 손실이 발생함을 알 수 있다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 전력전자학술대회 논문집
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• pp.418-422
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• 1998

A new single stage AC/DC converter based on the forward converter is proposed. The proposed converter offers both the high power factor and the direct conversion from ac line to dc output voltage. Also, the proposed converter reduces the diode conduction loss, so improves the overall efficiency of the converter, compared with other alternatives. The principles of operation and the simulation results of the proposed converter are presented. A 100 W prototype was built and tested to show the potential of applications of the proposed converter.

• 대한설비공학회지:설비저널
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• 제4권1호
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• pp.6-17
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• 1975

For a periodic variation of the flue gas temperature the heat conduction through the Ondol floor was analysized. Also the heat loss to the ground was estimated. The floor thermal capacity, as a function of the floor thickness, has strong influence on the time lag of the temperature variation. It is an important design parameter for intermittent heating. Even for the steady periodic variation, there was significant heat loss to the ground below the Ondol floor.

• 반도체디스플레이기술학회지
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• 제19권4호
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• pp.22-27
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• 2020

In this paper, a generalized efficiency equation was proposed to estimate the internal loss of the SMPS (switched-mode power supply) with 3 variables. The first variable was an internal loss not related to the load current such as auxiliary power, the second was a loss proportional to the current such as diode loss, and the third was a loss proportional to square of the current such as conduction loss. Especially, theoretical internal losses of the totem pole bridgeless PFC which is widely used for high efficiency SMPS were expressed as output function to compare generalized efficiency equation. In addition, in order to reduce the conduction loss of the switch, when a multiple switch were paralleled, the correlation with the efficiency was analyzed and shown as a graph. In order to confirm the degree of the parallel switch structure on the efficiency improvement, a 2kW class totem pole bridgeless PFC was constructed and the effectiveness of the analysis was confirmed by comparing the generalized efficiency equation and theoretical loss analysis results with experimental data.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2017년도 추계학술대회
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• pp.43-44
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• 2017

This paper presents design of auxiliary circuit to reduce loss of ZVT interleaved flyback converter. The ZVT interleaved converter using the conventional auxiliary circuit has a large conduction loss due to the constant circulating current in the auxiliary circuit. The auxiliary circuit proposed in this paper, which consists of the coupled inductor and DC-link capacitor, has linearly increasing or decreasing auxiliary current. Then, the conduction loss occurring in the auxiliary circuit is reduced. The validity of the proposed auxiliary circuit is verified with the prototype of 500W.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2017년도 추계학술대회
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• pp.101-102
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• 2017

This paper presents analysis of losses of switching device for full bridge inverter connected to grid. The losses are a dominant factor that judges efficiency of the system. The losses of switching device are divided to switching loss and conduction loss. They are can be estimated by analyzing periodic switching waveforms. The switching loss is generated at the point that turn-on and off. And the conduction loss is generated while the switch is on condition. The estimated losses of switch are compared to simulation result in this paper.

• 전자공학회논문지S
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• 제34S권6호
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• pp.77-84
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• 1997

buck type converter doesn't appear when an input voltag eis lower than an output voltage. This is the main reason the buck converter has not been used for high power factor converters. In this paper, soft switching high power factor buck converter is proposed. This converter is composed of diode rectifier, input capacitor can be small enough to filter input current, buck converter with loss less snubber circuit. Converter is operated in discontinous conduction mode, turn on of the switching device is a zero current switching (ZCS) and high powr factor input is obtianed. In addition, zero voltage switching (ZVS) at trun off is achieved and switching loss is reduced using loss less snubber circuit. The capacitor used in the snubber circuit raised output voltage. Therefore, proposed converter has higher output voltage and higher efficiency than conventional buck type converter at same duty factor in discontinous conduction mode operation. High power factro, efficiency, soft switching operation of proposed converter is veified by simulation using Pspice and experimental results.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.549-551
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• 2005

Bidirectional DC/DC converters allows transfer of power between two dc sources, in either direction. Due to their ability to reverse the direction of flow of power, they are being increasingly used in many applications such as battery charger/dischargers, dc uninterruptible power supplies, electrical vehicle motor drives, aerospace power systems, telecom power supplies, etc. This paper proposes a new bidirectional Sepic/zeta converter. It has low swicthing loss and low conduction loss due to auxiliary communicated circuit and synchronous rectifier operation, respectively. Because of positive and buck/boost-like DC voltage transfer function(M=D/1-D), the proposed converter is very desirable for use in distributed power system . The proposed converter also has both transformerless version and transformer one.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 B
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• pp.1177-1179
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• 1993

A study has been carried out on the characteristics of dielectric consent and the dissipation factor of Eicosamethyl Eneasiloxane as a function of frequency($30{\sim}10^5$[Hz]) and temperature(-70[$^{\circ}C$] to 65[$^{\circ}C$]). The result shows that a well-defined maxima of the absorption curves characterized by a dipole loss mechanism at a low temperature range. For temperatures in the vicinity of room temperature and higher, the loss in the range of power frequencies are predominantly of ionic nature. The increase of ionic conduction is attributed to the presence of ionizable oxidation products and their increased dissocation feature. The effect of viscosity upon the dipole loss intensity appeared to be considerably less pronounced than that upon ionic conduction loss.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 전력전자학술대회
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• pp.147-148
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• 2011

In this paper, implementation of digital control for critical conduction mode power factor correction (PFC) rectifier is presented. Critical conduction mode is widely used in medium and low power conversion application due to its minimized MOSFET turn-on loss and diode reverse-recovery problem. However, it needs additional zero current detection circuit and maximum frequency limit to properly turn the MOSFET on and avoid the excessive switching loss in light load operation. This paper explains the digital IC implementation and verifies its operation with 200-W prototype PFC rectifier.