• 제목/요약/키워드: W-beam

검색결과 1,046건 처리시간 0.027초

750kW 풍력발전기 타워 구조의 진동 특성 (Vibration Characteristics of the Tower Structure of a 750kW Wind Turbine Generator)

  • 김석현;남윤수;은성용
    • 한국소음진동공학회논문집
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    • 제15권2호
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    • pp.219-224
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    • 2005
  • Vibration response of the tower structure of a 750kW wind turbine (W/T) generator is investigated by measurement and analysis. Acceleration response of the W/T tower under various operation condition is monitored in real time by the vibration monitoring system using LabVIEW. Resonance state of the tower structure is diagnosed in the operating speed range. Resonance frequency range of the test model is investigated with the wind speed data of the test site. To predict the tower resonance frequency, tower is modeled as an equivalent beam with a lumped mass and Rayleigh energy method is applied. Calculated tower bending frequency is in good agreement with the measured value and the result shows that the simplified model can be used in the design stage of the W/T tower.

수소 Plasma 처리 후의 MgO 보호막에 대한 일함수 변화 측정 (Measurement of Changes in Work Function on MgO Protective Layer after H2-plasma Treatment)

  • 정재천;이석주;조재원
    • 한국전기전자재료학회논문지
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    • 제20권7호
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    • pp.611-614
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    • 2007
  • The changes in the work $function({\Phi}_w)$ in the MgO protective layers after $plasma(Ar,\;H_2)$ treatment have been studied using ${\Upsilon}-focused$ ion beam $({\Upsilon}-FIB)$ system. The ${\Phi}_w$ was determined as follows: Ar-plasma $treatment({\Phi}_w=4.52eV)$, $H_2-plasma$ $treatment({\Phi}_w=5.65eV)$, and non-plasma $treatment({\Phi}_w=4.64eV)$. The results indicated that the H-plasma could not make any effective physical etching due to the small masses of hydrogen atoms and molecules while the hydration of H-plasma could grow some contaminating materials on the surface of MgO.

200-W Continuous-wave Thulium-doped All-fiber Laser at 2050 nm

  • Shin, Jae Sung;Cha, Yong-Ho;Chun, Byung Jae;Jeong, Do-Young;Park, Hyunmin
    • Current Optics and Photonics
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    • 제5권3호
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    • pp.306-310
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    • 2021
  • A 200-W continuous-wave thulium-doped all-fiber laser at 2050 nm was developed with a master oscillator power amplifier configuration. For the master oscillator, a single-mode thulium-doped fiber laser was built with fiber Bragg gratings. The operating power of the oscillator was 10.1 W at a pump power of 20.9 W, and the slope efficiency was measured to be 53.0%. All emitted wavelengths of the oscillator were located between 2049.2 nm and 2049.9 nm, and no other peaks in different wavelength ranges were observed. The maximum output power of the final amplified beam was 204.6 W at a pump power of 350.4 W. The slope efficiency of the amplifier was measured to be 58.4%.