• Title/Summary/Keyword: residual rotation

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A Study on the Rotation-Induced Birefringence in Plastic Disk Substrate (회전에 의해 플라스틱 기판에 추가로 발생하는 복굴절의 측정에 관한 연구)

  • 김종선;윤경환
    • Transactions of Materials Processing
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    • v.12 no.8
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    • pp.730-737
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    • 2003
  • Extensive studies have been conducted for reducing the residual stresses and birefringence in injection-molded optical disk substrate Flow-induced and thermally-induced stresses and birefringence have been found as two main sources during injection molding process. However, high speed rotation also induces extra stresses and birefringence in real operation of disk drives. In the present paper rotation-induced in-plane birefringence has been measured and presented for CD and DVD substrates at different radial position. About 10 - 15 nm of extra retardation in one pass has been measured up to 4,800 rpm. The distribution of extra rotation-induced birefringence will be valuable data for designing an optimal optical disk substrate. Finally, experimental results were compared with the extra stresses calculated from simple formulation.

Optimized Washing Method for Performance Improvement of a Washing Machine for Boxthorn Berries (구기자 세척기의 세척성능 향상을 위한 최적 세척방법 구명)

  • Kim, Woong;Lee, Seung-Kee;Jo, Hee-Jae;Han, Jae Woong
    • The Korean Journal of Community Living Science
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    • v.24 no.2
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    • pp.187-194
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    • 2013
  • The purpose of this study was to define the optimal boxthorn berries washing method for developing the boxthorn berries cleaner. We analyzed the rate of removal of residual pesticides according to washing methods; 1st - habitual washing method, 2nd - drum rotation washing method, 3th - drum rotation and air bubble washing method, 4th - drum rotation and nozzle spray washing method, 5th - drum rotation and air bubble and nozzle spray washing method. A rate of removal of residual pesticides of 88% was detected in the drum rotation and air bubble and nozzle spray washing method, and a rate of 82% was detected in the habitual washing method. The drum rotation and air bubble and nozzle spray washing method appeared to be the best good washing effect compared to the habitual washing method(about 6% compared to 82.0% higher). Clothianidin Triadimefon, Triforine ingredients, the drum rotation and air bubble and nozzle spray washing method efficiency was lower compared to the habitual washing method removal efficiency.

A Study on the Rotation-induced Birefringence in Plastic Disk Substrate (회전에 의한 플라스틱 기판에 야기되는 복굴절의 측정에 관한 연구)

  • 김종선;윤경환
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2003.05a
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    • pp.470-473
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    • 2003
  • Extensive studies have been conducted for reducing the residual stresses and birefringence in injection-molded optical disk substrate. Flow-induced and thermally-induced stresses and birefringence have been found as two main sources during injection molding process. However, high speed rotation also induces extra stresses and birefringence in real operation of disk drives. In the present paper rotation-induced in-plane birefringence has been measured and presented for CD and DVD substrates at different radial position. About 10 - 15 nm of extra retardation has been measured up to 4,800 rpm.

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Elimination of Residual Phase Rotation Errors in SC-FDE Received Signals (SC-FDE 수신 신호의 잔여 위상회전에러 제거)

  • Kim, Ji-Heon;Kim, Whan-Woo
    • Proceedings of the IEEK Conference
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    • 2006.06a
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    • pp.101-102
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    • 2006
  • Similar to Orthogonal Frequency Division Multiplexing (OFDM), a Single Carrier with Frequency Domain Equalization (SC-FDE) system is computationally efficient since equalization is performed on a block of data in the frequency domain. In coherent QAM schemes, the mean phase rotation error caused by the residual carrier frequency offset may lead to serious degradation. When the frequency equalizer is combined with the mean phase error tracking algorithm, its performance can be enhanced noticeably.

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On-line Balancing of a Ultra-high speed Rotor with Residual Unbalance (자기베어링을 이용한 잔류질량불균형이 존재하는 초고속 회전체의 온라인 밸런싱)

  • 송상호
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.7 no.1
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    • pp.51-57
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    • 1998
  • In order to minimize vibration problems of rotating machinery rotors have been assembled through balancing machines. Since perfect balancing is impossible, residual unbalances cause serious vibration while the rotor is in high speed region. To minimize unbalance effects of magnetic bearing systems (AMB) during rotation on-line balancing methodology was studied. Unbalances were considered as disturbances of the system. The disturbance observer was used to estimate unbalance force from measurable state and input variables. Balancing inputs computed according to LQR and outputs of the observer were applied to eliminate unbalances during high speed rotation of the AMB. the effectiveness of the on-line balancing was verified through numerical simulations.

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Reduction of the Residual Vibrations of a Flexible Cantilever Beam Subjected to a Transient Translation or Rotation Motion (병진 또는 회전하여 위치 이동하는 유연 외팔보의 잔류진동 저감 방법)

  • Shin, Ki-Hong
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.18 no.1
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    • pp.3-10
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    • 2008
  • In this paper, the optimal command input is considered in order to minimize the residual vibrations of a flexible cantilever beam when the beam simply changes its position by translation or rotation. Although a cantilever beam has many modes of vibration, it is shown that the consideration of the first mode is sufficient in this case. Thus, the problem becomes a single-degree-of-freedom system subjected to a ground excitation. Two simple methods are proposed to find the optimal command input based on the shock response spectrum (SRS). The first method is the simplest and can be applied to lightly damped cases, and the second method is applicable to more general problems. The second method gives almost the same results as the input shaping method. However the proposed method gives a easier and clearer control strategy.

Residual salt separation technique using centrifugal force for pyroprocessing

  • Kim, Sung-Wook;Lee, Jong Kwang;Ryu, Dongseok;Jeon, Min Ku;Hong, Sun-Seok;Heo, Dong Hyun;Choi, Eun-Young
    • Nuclear Engineering and Technology
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    • v.50 no.7
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    • pp.1184-1189
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    • 2018
  • Pyroprocessing uses various molten salts during electrochemical unit processes. Reaction products after the electrochemical processes must contain a significant amount of residual salts to be separated. Vacuum distillation is a common method to separate the residual salts; however, its high operation temperature may cause side reactions. In this study, a simple rotation technique using centrifugal force was suggested to separate the residual salts from the reaction products at relatively low temperature compared to the distillation technique. When a reaction product container with porous wall rotates inside a vessel heated above the melting point of the residual salt, the residual salt in the liquid phase is separated through centrifugal force. It was shown that the $LiNO_3-Al_2O_3$ mixture can be separated by this technique to leave solid $Al_2O_3$ inside the container, with a separation efficiency of 99.4%.

A Study on the Detection of Axis-Rotation in Contact Lenses (콘택트렌즈 회전량 검출에 대한 연구)

  • Lee, Dong-Hee;Kim, Jung-Hee;Cha, Jung-Won
    • Journal of Korean Ophthalmic Optics Society
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    • v.10 no.4
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    • pp.255-259
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    • 2005
  • When we wear contact lenses for correcting astigmatism, we often experience the axis-rotation of contact lenses that is happened in case we could not fit the axis of lens exactly or by the eyelid used to blink. In this case, because the exact correcting state becomes in the wrongly correcting state, the asthenopia is led, and the decline of eyesight can be led. For this reason, we need to know axis-rotating degrees of contact lenses. If a contact lens rotated, a residual astigmatism may be detected in the refraction examination after wearing. Using this, we developed a program that calculates the axis-rotating amount of contact lenses.

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Suppression of Output Distortion in a Gyroscope using Fiber Amplifier/Source by Tracking of Optimum Modulation Amplitude

  • Park, Hee-Gap
    • Journal of the Optical Society of Korea
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    • v.3 no.2
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    • pp.80-85
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    • 1999
  • We propose and demonstrate a new scheme for suppression of output distortion in an open-loop gyroscope employing an erbium-doped fiber amplifier/source (FAS). In addition to the main modulation for the rotation rate measurement, a small auxiliary modulation at a different frequency is used to extract an error signal, which is necessary for keeping the quasi-dc component of the feedback signal power at a constant level for varying rotation rate. By active tracking of the optimum modulation condition using this two-frequency modulation scheme, we obtain stable gyro output with suppressed distortion as well as stable FAS characteristics. We also calculate the distortion in the gyro response due to the feedback effect, from which we estimate the FAS gyro output distortion due to the residual ac feedback effect when the dc feedback effect is removed by the proposed scheme. The measured residual deviation agrees reasonably with the estimation.

Optimal Command Input for Suppressing the Residual Vibrations of a Flexible Cantilever Beam Subjected to a Transient Translation or Rotation Motion and Its Comparison with the Input Shaping Method (병진 또는 회전하여 위치 이동하는 유연 외팔보의 잔류진동 저감을 위한 최적 명령 입력 및 입력 다듬기 방법과의 비교)

  • Shin, Ki-Hong
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.589-594
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    • 2007
  • In this paper, the optimal command input is considered in order to minimize the residual vibrations of a flexible cantilever beam when the beam simply changes its position by translation or rotation. Although a cantilever beam has many modes of vibration, it is shown that the consideration of the first mode is sufficient in this case. Thus, the problem becomes a singledegree-of-freedom system subjected to a ground excitation. Two simple methods are proposed to find the optimal command input based on the Shock Response Spectrum (SRS). The first method is the simplest and can be applied to lightly damped cases, and the second method is applicable to more general problems. The second method gives almost the same results as the input shaping method. However the proposed method gives a easier and clearer control strategy.

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