• Title/Summary/Keyword: noise resistance

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An optical instrumentation using a sensor with a sensordummy against noises on sensor and transmission line

  • Mine, Katsutoshi;Kubota, Nobuhisa;Morimoto, Fumio;Sanada, Mizuho;Qi, Zhang
    • 제어로봇시스템학회:학술대회논문집
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    • 1993.10b
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    • pp.550-553
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    • 1993
  • Methods of Alternating Noise Canceling were previously developed for the optical instrumentation;one using a dual photo sensor and another using a single photo sensor that could cancel normal mode noise on a transmission line, even if the noise was of equal status noise. But the methods could not remove noise on sensor line. This paper discusses a new method of using a photo sensor with a resistance sensordummy, effectively canceling equal status normal mode noise not only on a sensor line but also on a transmission line of an optical instrumentation. The accuracy of this method has been verified by experiments using sinusoidal wave as an equal status noise on a sensor line and/or rectangular wave as an equal status wide band noise on a transmission line respectively.

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Reduction of Flow-Induced Noise in Suction Nozzle of a Vacuum Cleaner by Adopting a Cross-Flow Fan (횡류팬을 적용한 진공청소기 흡입노즐내 유동 소음 저감에 관한 연구)

  • Park, I-Sun;Sohn, Chae-Hoon;Lee, Sung-Cheol;Oh, Jang-Keun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.935-938
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    • 2007
  • In suction nozzle of a vacuum cleaner, where flow-induced noise is generated mainly by flow resistance, several ideas to reduce noise are investigated. To increase fan performance, blade number is optimized and a centrifugal fan is replaced by a cross-flow fan, In addition, gear ratio of fan to drum brush is changed. It is found that fan performance is increased by adopting these methods. Next, the blade height of the fan is decreased to reduce sound pressure level, which causes inevitably decrease in fan performance. Eventually, flow-induced noise is reduced by 6.3 dBA in its overall level with the fan performance maintained.

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Study on Noise Behavior of GaAs SBGFET (GaAs SBGFET의 잡음동작에 관한 연구)

  • 박한규
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.14 no.3
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    • pp.6-11
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    • 1977
  • The noise behavior of the Schottky Barrier Gate FET has been investigated by the use of noise equivalent circuit. It has been found that an additional noise source has to be taken into account in the GaAs SBGFET's biased in the pinch-off region; the intervalley scattering noise and the hot electron noise. In this paper, a noise equivalent circuit has been used to determine the noise parameter which was taken into account influence of the saturation velocity of carrier and parasitic resistance.

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Investigation of Characteristics and Suggestion of Evaluation Formulae for Skin Resistance of SIP (SIP 말뚝의 주면저항력 특성 고찰 및 산정식 제안)

  • Lim, Hae-Sig;Park, Yong-Boo;Park, Jong-Bae
    • Journal of the Korean GEO-environmental Society
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    • v.3 no.2
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    • pp.15-21
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    • 2002
  • Because of the environmental problem during the pile driving, the use of low noise-vibration auger-drilled pilling is increasing to solve noise and vibration problem in pilling. In Korea, SIP (Soil-Cement Injected Precast Pile) method is mainly used as auger-drilled pilling. But, a proper bearing capacity evaluation formula has not been suggested, yet. To improve and supplement this situation, direct shear tests between SIP pile skin interface and soil were executed under various conditions. Through the analysis of test results, skin resistance characteristics of SIP were investigated thoroughly. Also, the maximum unit skin resistance capacity evaluation formulae on SM, SC soil was suggested.

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Suggestion of Evaluation Formula for Skin Resistance of SIP (SIP말뚝의 주면저항력 예측 모델 제안)

  • Chung, Hyung-Sik;Lim, Hae-Sig;Kim, Jung-Soo
    • Journal of the Korean GEO-environmental Society
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    • v.4 no.1
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    • pp.59-66
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    • 2003
  • The environmental problem due to the pile driving, the use of low noise-vibration auger-drilled pilling is increasing to solve noise and vibration problem in pilling. Therefore, in Korea, SIP (Soil-Cement Injected Precast Pile) method is mainly used as auger-drilled pilling. However, a proper bearing capacity evaluation formula has not been suggested, yet. In order to improve and supplement this situation, direct shear tests between SIP pile skin interface and soil were executed under various conditions. Through the analysis of test results, skin resistance characteristics of SIP were investigated thoroughly. Also, the nonlinear unit skin resistance capacity model and relative parameters evaluation formula with SM, SC soil were suggested.

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