• 전력전자학회:학술대회논문집
• /
• 전력전자학회 1997년도 전력전자학술대회 논문집
• /
• pp.441-444
• /
• 1997

This paper describes the bending traveling-wave type ultrasonic motor which generates the traveling wave by combining two standing waves with phase difference time and space. In +2$0^{\circ}C$~3$0^{\circ}C$, the operation characteristic of USM has represented normal condition. But in the other temperature, the operation characteristic of USM has abnormal condition, that is driving frequency, drive current and r.p.m are down. The recent USM has controller without temperature compensation. This study aimed at fuzzy controller which must follow the frequency at operation temperature and then r.p.m and torque increased.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2009년도 추계학술대회 논문집
• /
• pp.91-91
• /
• 2009

Piezoelectric micro-pump should contain the physical running parts like check valves for acquiring the unilateral motion of fluid from the alternating motion of actuators. But the check valves raise many problems such as abrasion or exhaustive destruction by the recursive mechanical displacement To solve these problems, we propose a novle type piezoelectric valveless micro-pump using peristaltic motion due to the traveling wave excitation. Proposed pump model is consisted of two piezoelectric ceramic plates, elastic metal body, caps for covering flow path, rubber rings for sealing tightly and disk springs for the pressurization of pump body.

• Coupled systems mechanics
• /
• 제7권3호
• /
• pp.269-280
• /
• 2018

Post-earthquake damages investigation in past and recent earthquakes has illustrated that the ground motion spatial variation plays an important role in the structural response of long span bridges. For the structural control of seismic-induced vibrations of cable-stayed bridges, it is extremely important to include the effects of the ground motion spatial variation in the analysis for design of an effective control system. The feasibility and efficiency of different vibration control strategies for the cable-stayed bridge under multiple support excitations have been examined to enhance a structure's ability to withstand earthquake excitations. Comparison of the response due to non-uniform input ground motion with that due to uniform input demonstrates the importance of accounting for spatial variability of excitations. The performance of the optimized designed control systems for uniform input excitations gets worse dramatically over almost all of the evaluation criteria under multiple-support excitations.

• 한국항행학회논문지
• /
• 제8권1호
• /
• pp.38-47
• /
• 2004

레이다에서 도플러 측정과 MTI(Moving Targer Indicator), 고해상도 등의 기능을 수행하기 위해서는 송신 및 수신회로 전체가 코히어런트 시스템으로 동작하여야 한다. 본 논문에서는 코히어런트로 동작하는 레이다의 송수신단을 설계하기위해 TWTA(Traveling Wave Tube Amplifier)와 STALO(Stable Local Oscillator) 및 COHO(Coherent Oscillator)를 사용하였으며, 설계된 수신단에서의 잡음지수를 계산하였다. 계산된 잡음지수로 레이다 방적식을 이용하여 각 송신모드별로 최대 탐지 거리를 산출하였다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제49권6호
• /
• pp.450-456
• /
• 2000

In this paper, we proposed a novel control method which uses the internal impedance angles as a control parameter to drive traveling wave type ultrasonic motor. An impedance characteristic of the ultrasonic motor is obtained by analysis of the equivalent circuits including the external inductor used to generate the coupled resonance. The phase angle of internal impedance to achieve optimal control performance is derived. For the tracking of impedance angle, an information of phase difference is obtained from the applied voltage and current. The high speed phase difference detector is designed to monitor the phases of ultrasonic motor. The effectiveness of the proposed control scheme is clarified by experiments.

• 대한전자공학회논문지
• /
• 제10권2호
• /
• pp.1-6
• /
• 1973

전기광 물질이 부분적으로 장하된 구형도파관을 이용한 진행파 레이저 위상 변조기에 대해 이론적으로 해석하였으며, 전파특성, 전계분포 감쇄량과 변조도를 정규화된 항으로 표시했다. 여기서 비교적 낮은 변조전력으로 큰 변조도를 얻었으며, 또한 KDP를 사용한 변조기의 설계방법을 제시했다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
• /
• pp.215-216
• /
• 2008

Using the extensional vibration mode of PZT ring, a piezopump is successfully made. The PZT ring is polarized with thickness direction. The traveling extensional wave along the circumference of the ring is obtained by dividing two standing waves which are temporally and spatially phase shifted by 90 degrees from each other. The proposed piezopump is consisted of coaxial cylindrical shells that are bonded piezoelectric ceramic ring.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1993년도 정기총회 및 추계학술대회 논문집 학회본부
• /
• pp.198-200
• /
• 1993

This paper represents the experimental results of electrohrdrodynamic(EHD) micropump driven by traveling- wave voltage. We fabricated 60 electrodes array with $100{\mu}m$ width and $100{\mu}m$ interval on the pyrex glass. On that glass we fabricated the micro channel which had the cross section of 3mm by 0.5mm. This pump was driven by 6 phase square traveling-wave voltage. We used the corn oil for experiments and increased the temperature of fluid by resistive heater. An optical microscope with CCD camera and monitor was used for observation. The fluid velocity was large for the large driving voltage and the high temperature. This EHD pump had the fluid velocity in specific frequency (near 1Hz) which had relation to the charge relaxation time in that oil.

• 전자공학회논문지A
• /
• 제29A권8호
• /
• pp.41-48
• /
• 1992

The characteristics of traveling-wave electrodes for high-frequency electroptic integrated devices are described from the view point of improvement of phase-matching based on the conformal mapping method. Specific calculations of the characteristic impedance, effective microwave index, and eletrode loss for asymmetric coplanar strip(ACPS) and coplanar waveguide(CPW) electrode structures are presented as a function of the geometric electrode parameters including the electrode thickness and buffer layer thickness. 5-10(x10S0-6Tm) thick Au-ACPS electrodes were successfully fabricated by electroplating and ECR etcher. The improvement of modulation bandwidth can be theoretically observed from the combination of electrode and buffer layer thickness.

• 전자공학회논문지A
• /
• 제32A권1호
• /
• pp.119-128
• /
• 1995

We report hybrid and passive mode-locking results of tilted-stripe AlGaAs semiconductor laser traveling wave amplifiers with saturable absorbers. Dependence ofthe pulse width on the mode locking frequency, the bandwidth of spectral filters, and the bias current of the laser amplifier are investigated. We generate 4 ps optical pulses by using the hybrid mode locking technique. The repetition rate and the peak power of generated pulses are 516 MHz and 170 mW, respectively. The tuning range of uor mode locked laser is 10 nm with the center wavelength of 780 nm. We also generate 2.6 ps optical pulses with peak power of 830 mW by using the passive mode locking technique.