• 전자공학회논문지
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• 제50권8호
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• pp.151-161
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• 2013

본 논문에서는 입력전압을 감지하지 않는 전류연속/임계동작모드 active power factor correction(PFC) circuit을 제안하였다. 기존의 입력전압을 감지하지 않는 PFC circuit의 경우 출력전류가 낮은 경 부하 조건에서 DCM 동작을 수행하고, 이에 따라 PF가 감소하는 문제가 발생한다. 제안한 PFC circuit은 70KHz의 주파수로 CCM 동작을 수행하고, 경 부하 조건에서 최대 200KHz까지 스위칭 주파수가 가변되는 CRM 동작을 수행하도록 하였다. 이를 통해 경 부하 조건에서 PF가 감소하는 문제를 해결하였다. PFC controller IC는 $0.35{\mu}m$ BCDMOS 공정을 이용하여 제작하였으며, 240W급 PFC prototype을 제작하여 실험하였다. 제안한 PFC circuit은 기존의 PFC circcuit 대비 최대 10%의 역률이 향상되었고, IEC 61000-3-2 Class D 규격에 따른 경 부하 조건에서는 최대 4% 역률이 향상되었다.

• 간호행정학회지
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• 제19권2호
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• pp.187-195
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• 2013

Purpose: The purpose of this study was to identify the relationship among followership, organizational commitment, job satisfaction, turnover intention, and customer orientation in hospital nurses. Methods: The participants in this study were 210 staff nurses in one university hospital. Data were analyzed using frequency, ANOVA, Pearson correlation analysis, and stepwise multiple regression. Results: Followership had positive correlations with organizational commitment (r=.46, p<.001), job satisfaction (r=.41, p<.001), customer orientation (r=.47, p<.001). Followership had negative correlation with turnover intention (r=-.23, p<.001). The factor of followership influencing organizational commitment was active engagement, and this factor accounted for 23.3% of explanatory power. The factor of followership influencing job satisfaction was active engagement (F=45.00, p<.001), and this factor accounted for 17.8% of explanatory power. The factor of followership influencing turnover intention was active engagement (F=19.69, p<.001), and this factor accounted for 17.0% of explanatory power. The factors of followership influencing customer orientation were active engagement (F=51.38, p=.004) and independent, critical thinking (F=24.55, p=.011), and these factors accounted for 22.1% of explanatory power. Conclusion: Findings indicate a need to develop followership to promote organizational commitment, job satisfaction, and customer orientation and to decrease turnover intention in nurses.

• Journal of Power Electronics
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• 제16권4호
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• pp.1541-1550
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• 2016

This paper presents a theoretical analysis and comparisons of active power filter (APF) and hybrid power filter (HPF) systems, given terminal constraints of harmonic compensations in nonlinear loads. Despite numerous publications for the two types of filters, the features and differences between them have not been clearly explained. This paper presents a detailed analysis of the operations of a HPF inverter along with those of passive power filters (PPFs). It also includes their effects on the power factor at the grid. In addition, a theoretical analysis and a systematic comparison between the APF and HPF systems are addressed based on system parameters such as the source voltage, output power, reactive component size, and power factor at the grid terminals. The converter kVA ratings and dc-link voltage requirements for both topologies are considered in the presented comparisons

• JSTS:Journal of Semiconductor Technology and Science
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• 제8권1호
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• pp.85-91
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• 2008

A Boost Power Factor Correction (PFC) Converter employing Zero Voltage Switching (ZVS) based Compound Active Clamping (CAC) technique is presented in this paper. An Electro Magnetic Interference (EMI) Filer is connected at the line side of the proposed converter to suppress Electro Magnetic Interference. The proposed converter can effectively reduce the losses caused by diode reverse recovery. Both the main switch and the auxiliary switch can achieve soft switching i.e. ZVS under certain condition. The parasitic oscillation caused by the parasitic capacitance of the boost diode is eliminated. The voltage on the main switch, the auxiliary switch and the boost diode are clamped. The principle of operation, design and simulation results are presented here. A prototype of the proposed converter is built and tested for low input voltage i.e. 15V AC supply and the experimental results are obtained. The power factor at the line side of the converter and the converter efficiency are improved using the proposed technique.

• 치위생과학회지
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• 제2권2호
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• pp.75-83
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• 2002

By extracting the variables related to the work stress generated from dental hygiene, identifying their relationships, this study aims to contribute to academic progress on work stress. The test results of this study are as follows for each hypothesis: 1. Among the work stress sensing factors, role ambiguity showed correlation to the active coping strategy and the passive coping strategy, whereas it did not have any correlation to the evasive reation. However, the physical resource environmental factor showed correlation to the active coping strategy, whereas it did not have any correlation to the other reation. 2. The passive coping strategy, among the work stress coping strategies, influences the role ambiguity, B type, work ambiguity, physical resource environmental factor by about 18.7%. 3. The active coping strategy, among the work stress coping strategies, influences the social support, role ambiguity, work place of health center factor by about 18.9%. 4. The evasive reaction, among the work stress coping strategies, was influenced by only the 36 years old over factor by approximately 4.2%. 5. It was found in all work stress sensing factors that the group with lower social support had a more degree of experiencing stress than the group with higher social support. In case of the behavior pattern, the type A experienced more stress than the type B only in role ambiguity. 6. It was found that the group with the higher social support tended to choose more active coping strategy than the lower social support. In case of behavior pattern, the type B coped more actively than type A in the passive coping strategy.

• 생명과학회지
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• 제12권4호
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• pp.477-482
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• 2002

효모 glucoamylase의 promoter와 분비신호서열 그리고 MF$\alpha$1의 prosequence를 이용하여 곤충 defensin을 S. cerevisiae 2805에서 항균활성을 보유한 형태로 발현 및 분비하는데 성공하였다. 발현된 defensin의 대부분이 세포 외로 분비되어 거의 모든 항균활성이 배양 상등액에 존재하였다. 이것은 S. cerevisiae에서 발현된 defensin이 glucoamylase의 분비신호서열과 MF$\alpha$1의 prosequenre에 의해 효율적으로 processing되어 분비됨을 시사한다. Defensin의 다른 미생물에 대한 항균활성을 조사한 결과 병원균인 St. aureus와 L. monocytogenes에 대해서도 항균활성이 존재하였다.

• Steel and Composite Structures
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• 제48권3호
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• pp.353-365
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• 2023

Shape memory alloys (SMAs) have emerged as a novel functional material that is being increasingly applied in diverse fields including medical, aeronautical and structural engineering to be used in the active, passive and semi-active structural control devices. This paper is mainly aimed at evaluating the ductility and response modification factor of the steel plate shear wall (SPSW) frames with and without the Ni-Ti shape memory alloys. To this end, different configurations were utilized, in which the walls were used in the first, third, middle, and all stories. The models were numerically analyzed using OpenSees Software. The obtained results indicate that improving the shape memory properties of alloys can greatly enhance the ductility and response modification factor. Furthermore, the model whose first and third stories are equipped with the SMA shear wall was found to be 290% more ductile, with a greater response modification factor compared to the unequipped frame.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.259-261
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• 1996

In this paper, active input filter for power factor correction(PFC) circuit employing ripple arrent and voltage cancellation is proposed to reduce filter's size and cost, and to make filter design easy. Switching ripple current and voltage can be sensed through the secondary windings of filter inductor. Single stage passive filter can achieve high order filter characteristics by using active ripple current and voltage cancellation technique. Conventional high order passive filter and its problems are suggested. Analysis of active filter and design procedure are detailed. Simulation result is presented to verify high order filter characteristics of proposed scheme.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(1)
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• pp.73-76
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• 2003

A zero voltage soft switching inverter using active clamp is presented for induction heating application. This converter have long been attractive because of its simplicity, high efficiency, and low cost compared to other schemes. In addition to those merits, Input power factor can be improved with a variable frequency control. In this paper, it describe the control method and operational principle to improve a power factor with a single stage US converter using active clamp for induction heating application.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2002년도 학술대회논문집
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• pp.287-291
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• 2002

This paper presents active-clamp class-E high frequency resonant inverter with single-stage. The proposed circuit is integrated active-clamp class-E circuit to boost converter with the function of power factor correction. Boost converter is operated in positive and negative half cycle respectively at line frequency(60Hz), Such a operating in discontinuous conduction mode(DCM) of boost converter performs high power factor. By adding active-clamp circuit in class-E inverter, main switch of inverter part is operated not only ZVS(Zero Voltage Switch) but also reduced the switching voltage stress of main switch. This paper shows that simulation result using Psim 4.1 prove the validity of theoretical analysis. This proposed inverter will be able to be practically used as a power supply in various fields as induction heating applications, DC-DC converter etc.