• Title/Summary/Keyword: pulse width

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Variable Pulse Generation Technology of Pusle ND:YAG Laser Using Real Time Multi-Discharge

  • Kim, Whi-Young
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.102.2-102
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    • 2001
  • In this study, a solid-state laser system adopting a new real time multi-discharge (RTMD) method in which three flashlamps are turned on consecutively was designed and fabricated to examine the pulse width and the pulse shape of the laser beams depending upon the changes in the lamp turn-on time. That is, this study shows a technology that makes it possible to make various pulse shapes by turning on three flashlamps consecutively on a real-time basis with the aid of a PIC one-chip microprocessor, With this technique, the lamp turn-on delay time can be varied more diversely from 0 to 10 ms and the real-time control is possible with an external keyboard, enabling various pulse shapes. In addition, longer pulses can be more widely used for industrial processing and lots of medical purposes.

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The effect of two temperatures on a FG nanobeam induced by a sinusoidal pulse heating

  • Zenkour, Ashraf M.;Abouelregal, Ahmed E.
    • Structural Engineering and Mechanics
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    • v.51 no.2
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    • pp.199-214
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    • 2014
  • The present investigation is concerned with the effect of two temperatures on functionally graded (FG) nanobeams subjected to sinusoidal pulse heating sources. Material properties of the nanobeam are assumed to be graded in the thickness direction according to a novel exponential distribution law in terms of the volume fractions of the metal and ceramic constituents. The upper surface of the FG nanobeam is fully ceramic whereas the lower surface is fully metal. The generalized two-temperature nonlocal theory of thermoelasticity in the context of Lord and Shulman's (LS) model is used to solve this problem. The governing equations are solved in the Laplace transformation domain. The inversion of the Laplace transformation is computed numerically using a method based on Fourier series expansion technique. Some comparisons have been shown to estimate the effects of the nonlocal parameter, the temperature discrepancy and the pulse width of the sinusoidal pulse. Additional results across the thickness of the nanobeam are presented graphically.

A high-efficiency short-pulse genrator module using mgnetic compression circuit (자기 압축회로를 이용한 고효율 단펄스 전원모듈 개발)

  • ;;Istomin-Y.A
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.34S no.4
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    • pp.66-74
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    • 1997
  • Recently, high-developed domestic industry and environmental issues demand high-voltage short-pulse power supply(power, voltage, pulse width and repetition rate of 100KW, 150KV, 500ns and 500Hz, respectively) for electron beam process and puolse corona process. In such power supplies magnetic compression circuit can be one of the effectives solutions. In ths study design and operation principle of a pulse-power supply with a three-stage magnetic-compression circuit are described. A good agreement between simulation and experimental results verifies the validity of thescheme. The system delivers energy of 10[J/pulse] at the efficiency of 82%[%].

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Experimental Study of DC Coronas in Point-to-Plane Short Gap (지간적 직류Corona의 실질적 검토)

  • 오철한;이성만
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.32 no.5
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    • pp.157-163
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    • 1983
  • Positive and negative coronas in point-to-plane short gap have been investigated with the variations of point radius and gap length. Mainly the onset potentials and current pulses under various conditions were measured with a 70 MHz C.R.O. and a precise-controllable D.C. power supply. In the case of negative corona, the Trichel pulse corona, glow corona and spark regions were distinguished apparently and the critical gap lengths between them were also found clearly. In the case of positive corona, there are streamer corona, spark regions and the critical gap length between them, too. The current pulse forms of Trichel pulse corona of negative and streamer pulse corona of positive are similar in rising time, peak-to-peak time and pulse width. The glow corona current shows D.C. component in form.

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Development of a High Voltage Pulsed Power System for Electrostatic Precipitators (500MW 화력 발전소 전기 집진기용 고압 펄스 전원 장치 개발)

  • Kim, Won-Ho;Gang, Yu-Ri;Lee, Gwang-Hak;Kim, Jong-Su;Im, Geun-Hui;Kim, Cheol-U
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.49 no.12
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    • pp.807-812
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    • 2000
  • With the increasing demands for clean environment, development of air cleaning systems has been received increasing attention. One of the key technologies in the electrostatic precipitator (EP) is high voltage pulsed power supply, which affects the performance of the overall system. In this study, a high voltage microsecond pulse power supply for the EP is developed for 500MW coal power plants. The power supply has dc source and a pulsed one. The ratings of the dc and the pulse source are 60kV, 800mA and 70kV, 400mA, respectively. The width of pulse voltage is 140us and the max. pulse repetition frequency is 200Hz.

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A study on the Pulse generation technology of Nd :YAG laser adopting a FTC method (FTC방식을 적용한 Nd:YAG 레이저의 펄스 발생 기술에 관한 연구)

  • Hong, Jung-Hwan;Kim, Kyu;Song, Kum-Young;Kim, Hee-Je;Kang, Uk;Kim, Whi-Young
    • Proceedings of the KIEE Conference
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    • 2002.07c
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    • pp.1807-1809
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    • 2002
  • In this study, asolid-state laser system adopting a firing time control(FTC) method in which three flashlamps are turned on consecutively was designed and fabricated to examine the pulse width and the pulse shape of the laser beams depending upon the changes in the lamp turn-on time. That is, this study shows a technology that makes it possible to make various pulse shapes by turning on three flashlamps consecutively on a real-time basis with the aid of a PIC one-chip microprocessor With this technique, the lamp turn-on delay time can be varied more diversely from 0 to 10 ms and the real-time control is possible with an external keyboard enabling various pulse shapes. In addition longer pulses can be more widely used for industrial processing and lots of medical purposes.

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Resonant Frequency Modulation of High Temperature Superconductors Subjected to Optical Pulse Energy and Temperature (광학 펄스 에너지와 온도 변화에 의한 고온 초전도체의 공명 진동수 변조)

  • Cho, Shin-Ho
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.18 no.11
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    • pp.1061-1067
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    • 2005
  • The resonant frequency modulation of $YBa_2Cu_3O_{7-x}$ meander lines has been investigated as functions of optical pulse energy and temperature by using a network analyzer. The frequency-domain measurements are performed by controlling both the resonant frequency and the frequency width. The meander lines, configured in a microstrip geometry, are illuminated by optical pulses from an actively mode-locked Nd:YAG laser. The variation of the resonant frequency shows a quadratic dependence on the reduced optical pulse energy $P/P_c$, where $P_c$ is defined as the critical optical pulse energy at which resonance signal has disappeared. As for the dependence on temperature, the results are in good agreement with the previously reported data.

Using Pulse-Front Tilt to Measure Laser Pulses Less Than 100 Picoseconds in Duration

  • Jeong, Hoon
    • Korean Journal of Optics and Photonics
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    • v.26 no.6
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    • pp.318-321
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    • 2015
  • We demonstrate a frequency-resolved optical grating (FROG) device for measuring the intensity and phase versus time of several-tens-of-picoseconds laser pulses, using a thick nonlinear optical crystal. The huge pulse-front tilt generated by a holographic grating increases the temporal range of the device, which can make a single-shot measurement of laser pulses less than 100 ps in duration. To verify the measurement technique, we generate double pulses using a Michelson interferometer. The measured duration of a single pulse is about 300 fs and the measured maximum delay of two pulses is 60 ps, which implies that the proposed FROG device can measure laser pulses with maximum pulse width of about 120 ps.

Development of 140kV, 20mA Rated High Voltage Pulsed Power System for Pilot EP (140kV, 20mA급 Pilot 집진기용 고압 펄스 전원장치 개발)

  • Kim, Won-Ho;Kang, Iou-Ri;Lee, Kwang-Hak;Kim, Jong-Soo;Rim, Geun-Hie;Kim, Chul-U
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.50 no.2
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    • pp.73-78
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    • 2001
  • With the increasing demands for clean environment, development of air cleaning systems has been received increasing attention. One of the key technologies in the electrostatic precipitator(EP) is high voltage pulsed power supply, which affects the performance of the overall system. In this study, a high voltage microsecond pulse power supply for the pilot EP is developed. The power supply has a dc source and a pulsed one. The ratings of the dc and the pulse source are 60kV and 70kV respectively. The width of pulse voltage is 140us and the maximum pulse repetition frequency is 200Hz.

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Effects of Light Pulse Intensity and Quencher Concentration on the Time-Dependent Fluorescence Quenching Kinetics

  • Yang Mino;Lee Sangyoub;Shin, Kook Joe;Choo Kwang Yul;Lee Duckhwan
    • Bulletin of the Korean Chemical Society
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    • v.13 no.3
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    • pp.325-331
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    • 1992
  • By using the general theoretical framework proposed recently for treating the fluorescence quenching kinetics, we investigate the effect of light pulse intensity on the decay of fluorescence which follows excitation of fluorophors by the light pulse of very short but finite duration. It is seen that conventional theory breaks down when the exciting light pulse has a pulse width comparable to the fluorescent lifetime and its intensity is very high. We also find that even when the light intensity is not too high, conventional theory may fail in either of the following cases: (i) when the quencher concentration is high, (ii) when there is an attractive potential of mean force between the fluorophor and quencher, or (iii) when the energy transfer from the fluorophor to the quencher may also occur at a distance, e.g., via dipole-dipole interaction. The validity of the predictions of the present theory may thus be tested by fluorescence quenching experiments performed under such situations.