• Journal of Power Electronics
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• 제7권2호
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• pp.124-131
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• 2007

In this paper, a novel type of auxiliary switched capacitor assisted edge resonant soft switching PWM resonant DC-DC converter with two simple auxiliary commutation lossless inductor snubbers is presented. The operation principle of this converter is described using the switching mode equivalent circuits. This newly developed multi resonant DC-DC converter can regulate its DC output AC power under a principle of constant frequency edge-resonant soft switching commutation by an asymmetrical PWM duty cycle control scheme. The high frequency power regulation and actual power characteristics of the proposed soft switching PWM resonant DC-DC converter are evaluated and discussed. The operating performances of the newly proposed soft switching inverter are represented based on simulation results from an applications point of view.

• 대한전자공학회논문지TC
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• 제48권7호
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• pp.28-34
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• 2011

영차 공진과 반파장 공진을 이용한 이중 모드 Inductor loaded 패치 안테나의 방사 특성을 연구하였다. 반파장 공진 모드에서 수평방향으로의 방사 이득을 최소화시키는 동시에 전방 방사 이득을 향상시켜 영차 공진 모드 방사 패턴과의 격리도를 향상시켰다. 이중 모드 inductor loaded 패치 안테나 기판의 유전상수가 작을수록, 안테나의 동작 주파수 대역이 높을수록 두 모드 간의 공진 주파수 간격이 증가함을 확인하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(2)
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• pp.777-780
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• 2003

In this paper, an improved full wave mode ZVT-PWM DC-DC Converter is presented to maximize the regeneration ratio of resonant energy by only putting an additional diode in series with auxiliary switch. The operation of auxiliary switch in a half wave mode makes possible the soft switching condition of all switches. Furthermore, the increase of the regeneration ratio to resonant energy results in low conduction losses and minimum voltage and current stresses. The operation principles of the proposed converters are analyzed using the PWM boost converter topology as an example. Theoretically analysis and experimental results verify the validity of the boost converter topology with the proposed full wave mode ZVT-PWM converters

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.200-203
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• 2002

This paper presents Continuous-current mode of $S^4$-PFC(Single-Stage Single-switch Power Factor Correction) converter. Proposed converter operates in the continueous current mode(CCM) at full load and discontinuous current mode(DCM) at light load. So, characteristic of proposed converter is no bus voltage stress and Zero Voltage Switching(ZVS) using resonant auxiliary circuit. And. This paper presents characteristic of $S^4$-PFC converter and effect of circuit parameter of proposed converter through the input inductor, PFC capacitor's variation. All of these theory and characteristic verified through the experiment with a 72W(12V, 6A), $90^{kHz}$ prototype converter.

• 한국전기전자재료학회논문지
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• 제11권10호
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• pp.855-860
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• 1998

This paper presents a new structure for a piezoelectric transformer, operating in thickness extensional vibration mode. Modified $PbTiO_3$ family ceramics were used for the piezoelectric transformer, because it was a material with large anisotropy between elecromechanical coupling factors $K_t$ and $K_p$ . The size of piezoelectric transformer was 20mn long, 20mm wide and 3.1mm thick. The second harmonic resonant frequency of thickness extensional vibration mode was 0.72MHz at loading resistance 100[$\omega$], And Voltage gin of piezoelectric ceramics showed 0.53 at resonant frequency of sencond thickness extensional vibration mode.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2009년도 춘계학술대회
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• pp.135-138
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• 2009

Cylindrical monopole antenna is one of most promising candidates for multi-band applications such as PCS, WLAN, DMB, and UWB wireless services. In this research, we analyze the current distributions of operating modes for a cylindrical double-resonant monopole antenna. Two modes, the standing wave mode in a lower band and the traveling wave mode in a higher band, are identified from CST software simulations. Finally, design formulas are derived form the simulation results.

• 한국해안해양공학회지
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• 제8권2호
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• pp.193-203
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• 1996

죽변항 내외의 2개 정점에 수압식 파고계를 설치하여 동계의 악천후시 현장관측을 실시하고 장주기 부진동 특성을 파악하였다. 관측자료 분석에 의한 공진주기 해석시 기존의 항내 정점에서 스펙트럼 에너지가 최대인 주기 및 그 분포 형태를 기준한 방법외에 항외에 대한 항내 정점에서의 상대 증폭비를 기준한 방법을 도입하였다. 자료 분석과 수치실험 결과 죽변항 수역의 제1 공진 모드는 약 12분에서 약 7배의 증폭비를 가지며 제2 공진 모드는 약 6분인 것으로 나타났다. 관측기간중 항내에서의 수면진동폭은 약 10-20 cm로 나타났으며 황천시 항내 정점에서 단주기파의 군파 효과 또는 이 성분이 장주기파에 중첩된 영향에 의한 것으로 생각되는 2-3분 부근의 부진동이 출현하였다. 단주기파와 장주기파에서 통상적으로 사용되는 반사율을 선형적으로 연결시킨 수치실험을 통하여 3분 이하 부진동에서의 증폭비를 비교적 잘 재현하였다.

• 한국소음진동공학회논문집
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• 제22권10호
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• pp.949-958
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• 2012

Position tracking control of a link of a slave manipulator which needed to track the corresponding link of a master manipulator was addressed in this paper. Since driving torque from motor is transmitted through a set of flexible cable to link, the motion control system is modeled by a two-mass model connected with elastic coupling which has finite stiffness. Relative vibration of two-mass resonant system is a serious problem to operate manipulator. This paper proposed sliding mode control to reduce resonant vibration and fine position tracking control. Also, a pseudo-sliding mode control which uses a saturation function instead of a signum function was discussed and showed that the pseudo-sliding mode control can improve disturbance regulation performance as well as guarantees fine command tracking without chattering which is an inherent drawback of basic sliding mode control. In addition, a disturbance observer based sliding mode control has been suggested to improve disturbance regulation performance. The feasibility of the proposed control design was verified along with some simulation results.

• Journal of the Optical Society of Korea
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• 제7권2호
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• pp.53-58
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• 2003

We report the formation of inner cladding modes in the optical fiber having an inner cladding structure. The inner cladding layer located between the core- and the cladding- layers of a conventional fiber might have, so called, inner cladding mode(s). The brief history of the inner cladding fiber and the spectral properties of the inner cladding mode are presented. By utilizing fiber gratings, the spectral properties of the inner cladding mode formed in Dispersion Compensating Fiber (DCF) are discussed. It was observed that one resonant peak of a long-period fiber grating was not sensitive to the variation on the cladding surface. With a fiber Bragg grating, a small group of unusual resonant Peaks was observed between the main Bragg Peak and the series of usual Peaks resulted from the mode coupling to counter-propagating cladding modes. Within the DCF by using fiber gratings, it is noted, at least one mode can be coupled to the inner cladding mode and a few outer cladding modes are severely affected by the inner cladding of the fiber.

• 한국생산제조학회지
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• 제21권5호
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• pp.784-789
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• 2012

Ultrasonic Cutting which uses a tuned blade resonant in a longitudinal mode, has been used to cut a range of materials from confectionery, baked products and frozen foods, to wood, bone, foams and composites. The Blade design typically uses finite element analysis, and it could be predicted vibration mode, gain and amplitude uniformity of the blade tip at resonant frequency. In this paper, FEA used to predict the vibration characteristic of the blade, and then the results were verified by analysis system of resonant frequency using the processed blade. The crack of the blade which is predicted from FEA was compared with the crack occurred by cutting experiment of rubber materials using the processed blade.