• Title/Summary/Keyword: Pulse-train

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Maximum Power Design of Bridge Rectifier for Triboelectric Nanogenerator Using Impedance Analysis (마찰전기 나노발전기의 임피던스 분석을 통한 정류기의 최대 전력 설계)

  • Yoon, Bo-Kyung;Lee, Jun-Young;Jung, Jee-Hoon
    • Proceedings of the KIPE Conference
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    • 2019.07a
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    • pp.233-235
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    • 2019
  • 에너지 하베스팅은 주변의 에너지를 수확하여 활용하는 기술로 이에 관련한 연구가 여러 분야에서 활발히 진행되고 있다. 마찰전기 나노발전기는 물리적인 움직임이나 마찰을 통해 발생되는 정전기를 이용하여 센서나 웨어러블 디바이스에 활용하는 에너지 하베스팅 기술 중 하나이다. 마찰전기 나노발전기는 ${\mu}W$(마이크로와트) 단위의 미소 전력을 생산함에도 불구하고, 다른 에너지 하베스팅 발전기들과 비교하여 큰 임피던스를 가지고 있어서 전력을 전달하기에 어려움이 있다. 또한 마찰전기 나노 발전기의 출력 전력은 Spike성 Pulse Train의 형태여서 다이오드 정류기가 필요하기 때문에, 정류기의 입력 임피던스와 마찰전기 나노 발전기의 출력 임피던스에 대한 분석을 이용한 임피던스 매칭 설계가 필요하다. 본 연구에서는 다이오드 정류기의 임피던스 모델을 유도하여 마찰전기 나노 발전기의 내부 임피던스와의 매칭을 통해 최대 전력을 전달하는 커패시터와 출력 부하 설계를 목표로 한다. 유도한 임피던스 모델에 대하여 실제 전력 실험을 통해 모델의 유효성과 정확성을 검증하고자 한다.

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Ultralow Intensity Noise Pulse Train from an All-fiber Nonlinear Amplifying Loop Mirror-based Femtosecond Laser

  • Dohyeon Kwon;Dohyun Kim
    • Current Optics and Photonics
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    • v.7 no.6
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    • pp.708-713
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    • 2023
  • A robust all-fiber nonlinear amplifying loop-mirror-based mode-locked femtosecond laser is demonstrated. Power-dependent nonlinear phase shift in a Sagnac loop enables stable and power-efficient mode-locking working as an artificial saturable absorber. The pump power is adjusted to achieve the lowest intensity noise for stable long-term operation. The minimum pump power for mode-locking is 180 mW, and the optimal pump power is 300 mW. The lowest integrated root-mean-square relative intensity noise of a free-running mode-locked laser is 0.009% [integration bandwidth: 1 Hz-10 MHz]. The long-term repetition-rate instability of a free-running mode-locked laser is 10-7 over 1,000 s averaging time. The repetition-rate phase noise scaled at 10-GHz carrier is -122 dBc/Hz at 10 kHz Fourier frequency. The demonstrated method can be applied as a seed source in high-precision real-time mid-infrared molecular spectroscopy.

The Analgesic Effect and the Mechanism of Electroacupuncture on Thermal Hyperalgesia in the Rat Model of Collagenase-induced Arthritis: Mediation by Adrenergic Receptors (Collagenase-induced Arthritis Rat Model에서 Thermal Hyperalgesia에 대한 전침(電鍼)의 진통효과(鎭痛效果) 및 기전연구: Adrenergic Mechanism에 대(對)한 연구(硏究))

  • Seo, Byung-Kwan;Park, Dong-Suk;Baek, Yong-Hyeon
    • Journal of Acupuncture Research
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    • v.28 no.2
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    • pp.57-67
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    • 2011
  • 목적 : Collagenase-induced osteoarthritis(OA) 동물 모델에서 전침의 adrenergic mechanism을 연구하고자 한다. 방법 : Collagenase-induced arthritis(CIA)를 유발하기 위하여 5주령의 male Sprague-Dawley rat의 뒷다리 좌측 무릎 관절에 0.05ml의 4mg/ml collagenase solution을 intra-articular 주입하고, 다시 4일 후에 같은 부위에 같은 농도의 collagenase solution을 intra-articular boosting injection 시행한 뒤, gross, histopathological features 및 biomarker activity 변화를 관찰하였다. 예비실험을 통하여 CIA rat model에서 진통효과를 발휘하는 것으로 확인한, 족삼리(足三里) ($ST_{36}$)에 대한 저빈도 train pulse EA stimulation (2Hz, 0.07 mA, 0.3ms)을 침치료 방법으로 적용하였다. 전침의 진통기전을 확인하기 위하여, ${\alpha}1$-adrenergic antagonist (prazosin, 1 mg/kg, i.p.), ${\alpha}2$-adrenergic receptor antagonist (yohimbine, 2mg/kg, i.p.), ${\alpha}1$-adrenergic receptor agonist(phenylephrine, 2mg/kg, i.p.), ${\alpha}2$-adrenergic receptor agonist(clonidine, $40{\mu}g$/kg, i.p.)을 전침시행 20분 전에 복강 내로 전처치하였다. Tail flick unit(Ugo Basile Model 7360)을 이용하여 열자극에 대한 통증역치를 측정하였다. 결과 : 퇴행성관절염 징후(gross, histopathological features)와 통증역치의 변화가 최대값을 나타내는 CIA 유발 4주차에 저빈도 전침자극(train pulse, 2Hz, 0.07mA, 0.3ms)을 족삼리($ST_{36}$)에 적용하였으며, 족삼리 전침의 진통효과는 ${\alpha}2$-adrenergic receptor antagonist(yohimbine, 2mg/kg, i.p.)전처치에 의해 억제되었으나, ${\alpha}1$-adrenergic antagonist(prazosin, 1 mg/kg, i.p.)전처치에는 억제되지 않았다. 또 ${\alpha}2$-adrenergic receptor agonist(clonidine, $40{\mu}g$/kg, i.p.)의 전처치를 통하여 유의한 synergistic analgesic effect가 관찰되었으나, ${\alpha}1$-adrenergic receptor agonist(phenylephrine, 2mg/kg, i.p.)의 전처치는 전침의 진통효과에 synergistic effect를 미치지 않는 것으로 나타났다. 결론 : 저빈도 족삼리 전침은 CIA로 유발된 염증성 통증에 대하여 진통효과를 발휘하며, 이는 ${\alpha}2$-adrenergic receptor에 의하여 매개되는 것으로 보이며 ${\alpha}1$-adrenergic receptor는 영향을 미치지 않는 것으로 사료된다.

A Study on the Design of Controller for Speed Control of the Induction Motor in the Train Propulsion System-1 (열차추진시스템에서 유도전동기의 속도제어를 위한 제어기 설계에 대한 연구-1)

  • Lee, Jung-Ho;Kim, Min-Seok;Lee, Jong-Woo
    • Journal of the Korean Society for Railway
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    • v.13 no.2
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    • pp.173-178
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    • 2010
  • Electric railroad systems consist of supply system of electric power and electric locomotive. The electric locomotive is adapted to high speed driving and mass transportation due to obtaining high traction force. The electric locomotive is operated by motor blocks and traction motors. Train speed is controlled by suppling power from motor blocks to traction motors according to reference speed. Speed control of the electric locomotive is efficient by spending minimum energy between motor blocks and traction motors. Recently, induction motors have been used than DC and synchronized motors as traction motors. Speed control of induction motors are used by vector control techniques. In this paper, speed of the induction motor is controlled by using the vector control technique. Control system model is presented by using Simulink. Pulse is controlled by PI and hysteresis controller. IGBT inverter is used for real-time control and system performance is demonstrated by simulating the induction motor which has 210[kW] on the output power.

A Study of LCD Panel Cleaning Effect of Plasma Generation Power Source (플라즈마 발생용 전원장치의 LCD 패널 세정효과에 관한 연구)

  • Kim, Gyu-Sik
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.45 no.5
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    • pp.44-51
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    • 2008
  • UV lamp systems have been used for cleaning of display panels of TFT LCD or Plasma Display Panel (PDP). However, the needs for high efficient cleaning and low cost made high voltage plasma cleaning techniques to be developed and to be improved. Dielectric-Barrier Discharges (DBDs), also referred to as barrier discharges or silent discharges have been exclusively related to ozone generation for a long time. In this paper, a 6kW high voltage plasma power supply system was developed for LCD cleaning. The 3-phase input voltage is rectified and then inverter system is used to make a high frequency pulse train, which is rectified after passing through a high-power transformer. Finally, hi-directional high voltage pulse switching circuits are used to generate the high voltage plasma. Some experimental results showed the usefulness of atmospheric plasma for LCD panel cleaning.

A Comparison of an Improvement Performance of S/N ratio with the Method of Weighting in DMTI System using a Uniform Pulse Train (일정한 펄스 예을 사용한 DMTI 시스템에서 Weighting 방법에 따른 S/N 북 개선 특성에 관한 비교)

  • Go, Seong-Seon;Lee, Jae-Gyun;Yun, Hyeon-Bo
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.22 no.1
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    • pp.41-45
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    • 1985
  • A degradation of the signal-to-noise ratio (SNR) in a digital moving target indicator system (DMTI System) can be Improved by weighting of the DMTI output pulses before the integration process. and it Is shown that the signal-to-noise ratio Is unproved as the nunlber of delay line cancellers. It is Known that signal-to-noise ratio obtained with optimum weighting is greater than that obtained with binomial weighting. An improvement performance of the signal-to-noise ratio for each case is presented through the results or a computter simulation.

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A Study on the Low Force Estimation of Skeletal Muscle by using ICA and Neuro-transmission Model (독립성분 분석과 신전달 모델을 이용한 근육의 미세한 힘의 추정에 관한 연구)

  • Yoo, Sae-Keun;Youm, Doo-Ho;Lee, Ho-Yong;Kim, Sung-Hwan
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.3
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    • pp.632-640
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    • 2007
  • The low force estimation method of skeletal muscle was proposed by using ICA(independent component analysis) and neuro-transmission model. An EMG decomposition is the procedure by which the signal is classified into its constituent MUAP(motor unit action potential). The force index of electromyography was due to the generation of MUAP. To estimate low force, current analysis technique, such as RMS(root mean square) and MAV(mean absolute value), have not been shown to provide direct measures of the number and timing of motoneurons firing or their firing frequencies, but are used due to lack of other options. In this paper, the method based on ICA and chemical signal transmission mechanism from neuron to muscle was proposed. The force generation model consists of two linear, first-order low pass filters separated by a static non-linearity. The model takes a modulated IPI(inter pulse interval) as input and produces isometric force as output. Both the step and random train were applied to the neuro-transmission model. As a results, the ICA has shown remarkable enhancement by finding a hidden MAUP from the original superimposed EMG signal and estimating accurate IPI. And the proposed estimation technique shows good agreements with the low force measured comparing with RMS and MAV method to the input patterns.

A Study on the Radar Jamming Signal Simulator Design for the Test & Evaluation (시험평가용 레이다 재밍신호 시뮬레이터 설계 연구)

  • 최성린;이상훈;정회인
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.27 no.2B
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    • pp.160-169
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    • 2002
  • While radar operator recognizes and tracks threat targets through the scope, it is essential to overcome the jamming signal that disturbs the normal operation of the radar. Therefore, to train operator and test the EW capability of the radar, this paper proposed the jamming signal simulation algorithm and design results to generate the deception jamming(range, velocity, angle deception and multiple false targets) and noise jamming signals(spot, barrage, swept spot and cover pulse noise). And also, the radar jamming signal simulator composed of the 6 constituents is developed on basis of the proposed algorithm and digital circuit design technique and confirmed the validity of the developed simulator by means of the test results to generate the various jamming signal.

Improvement of self-mixing semiconductor laser range finder and its application to range-image recognition of slowly moving object

  • Suzuki, Takashi;Shinohara, Shigenobu;Yoshida, Hirofumi;Ikeda, Hiroaki;Saitoh, Yasuhiro;Nishide, Ken-Ichi;Sumi, Masao
    • 제어로봇시스템학회:학술대회논문집
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    • 1992.10b
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    • pp.388-393
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    • 1992
  • An infrared range finder using a self-mixing laser diode (SM-LD), which has been proposed and developed by the Authors, can measure not only a range of a moving target but its velocity simultaneously. In this paper, described is that the precise mode-hop pulse train can be obtained by employing a new signal processing circuit even when the backscattered light returning into the SM-LD is much more weaker. As a result, the distance to a tilted square sheet made from aluminium or white paper, which is placed 10 cm through 60 cm from the SM-LD, is measured with accuracy of a few percent even when the tilting angle is less than 75 degrees or 85 degrees, respectively. And in this paper, described is the range-image recognition of a plane object under the condition of standstill. The output laser beam is scanned by scanning two plane mirrors-equipped with each stepping motor. And we succeeded in the acquisition of the range-image of a plane object in a few tens of seconds. Furthermore, described is a feasibility study about the range-image recognition of a slowly moving plane object.

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Measurements of Acoustic Properties of Materials by Spectral Analysis of Ultrasonic Pulses (초음파 펄스의 주파수해석에 의한 재료의 음향특성 측정)

  • Ha, Kang-Lyeol;Kim, Moo-Joon;Lee, Jong-Kyu;Kim, Sung-Boo;Noriyoshi, Chubachi
    • The Journal of the Acoustical Society of Korea
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    • v.14 no.6
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    • pp.40-47
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    • 1995
  • A system for measurement of ultrasonic velocity, attenuation and complex modulus of materials by using the spectral analysis method of pulses has been constructed and its performances are estimated. The system has a mechanical scanning part of an acoustic microscope with a ZnO plane wave transducer of the resonant frequency of 85MHz. Ultrasonic velocity has been obtained by the intervals of maxima (or minima) on the power spectrum of a pulse train reflected from the surface and bottom of a specimen, and attenuation has been obtained by the power spectra of three pulses reflected from the surface and the bottom of a specimen and the surface of a standard specimen. The measured results for materials such as fused quartz, polyester show that the system has very high accuracy.

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