• Title/Summary/Keyword: repetition maximum

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A Study on the Adjusting Output Energy of the $CO_2$ Laser Controlled Directly in AC Power Line

  • Noh, Ki-Kyong;Jeong, Jong-Jin;Chung, Hyun-Ju;Kim, Hee-Je
    • KIEE International Transactions on Electrophysics and Applications
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    • v.5C no.4
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    • pp.152-154
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    • 2005
  • We demonstrate a simple $CO_2$ laser by controlling firing angle of a TRIAC switch in ac power line. The power supply for our laser system switches the voltage of the AC power line (60Hz) directly. The power supply does not need elements such as a rectifier bridge, energy-storage capacitors, or a current-limiting resistor in the discharge circuit. In order to control the laser output power, the pulse repetition rate is adjusted up to 60Hz and the firing angle of TRIAC gate is varied from $45^{circ}$ to $135^{circ}$. A ZCS(Zero Crossing Switch) circuit and a PIC one-chip microprocessor are used to control the gate signal of the TRIAC precisely. The maximum laser output of 40W is obtained at a total pressure of 18 Torr, a pulse repetition rate of 60Hz, and a TRAIC gate firing angle of $90^{circ}$.

High Repetition Rate Optical Pulse Multiplication with Cascaded Long-period Fiber Gratings

  • Lee, Byeang-Ha;Eom, Tae-Joong;Kim, Sun-Jong;Park, Chang-Soo
    • Journal of the Optical Society of Korea
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    • v.8 no.1
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    • pp.29-33
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    • 2004
  • We propose and demonstrate a novel optical pulse multiplier applicable to OTDM (Optical Time Division Multiplexing) systems using cascaded long-period fiber gratings. We have exploited the fact that each mode in a fiber has a different propagation constant to obtain time delays among optical pulses. The proposed scheme could realize high-frequency optical pulse multiplication for optical short pulse trains. We have successfully implemented two, four, and eight times multiplications with the maximum repetition rate of 416.7 ㎓. The obtained pulse delays are well matched with the simulated ones.

Regenerative amplification of pulses in Nd:YLF (Nd:YLF 레이저 펄스의 재생식 증폭)

    • Korean Journal of Optics and Photonics
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    • v.3 no.1
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    • pp.37-42
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    • 1992
  • Nd:YLF regenerative amplifiers have proved to be reliable source for producing stable short pulses of high repetition rate. We used a convex-concave mirror design to optimize output energy and stability while minimizing the energy density on critical intracavity optical components. The Kd:YLF laser pulse is used as a seed pulse which has pulse width of 40 ps, energy of 100pJ, and wavelength of 1053 nm. The amplifier yields stable 1 mJ pulses at 3.5 kHz repetition rate, and the maximum energy is measured as 5 mJ.

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10kV High Repetitive Pulsed Power Generator (10kV 고 반복률 펄스 전원장치)

  • Jo, Hyun-Bin;Song, Seung-Ho;Jang, Sung-Roc;Ryoo, Hong-Je
    • Proceedings of the KIPE Conference
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    • 2019.07a
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    • pp.171-173
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    • 2019
  • In this paper, 10kV solid-state pulsed power modulator with high repetition rate is described. The modulator is based on a Marx generator that charges capacitors in parallel and discharges them in series. Twelve IGBTs and capacitors are connected in series to generate output voltages up to 10kV at a repetition rate of 100kHz. The volume of the modulator is 26.1 liters, and its maximum average output power is 10kW. Therefore, the compact design is achieved with a high power density of 380 W/L. Finally, it is confirmed that the pulsed power modulator can operate stably through the experiment results at 10kV 100kHz condition.

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Co-Channel Interference Cancellation in Cellular OFDM Networks PART II: Co-Channel Interference Cancellation in Single Frequency OFDM Networks using Soft Decision MLE CCI Canceler

  • Mohaisen, Manar;Chang, Kyung-Hi
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.7A
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    • pp.710-716
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    • 2007
  • In this paper, a new scheme of downlink co-channel interference (CCI) cancellation in OFDM cellular networks is introduced for users at the cell-edge. Coordinated symbol transmission between base stations (BS) is operated where the same symbol is transmitted from different BS on different sub-carriers. At the mobile station (MS) receiver, we introduce a soft decision maximum likelihood CCI canceler and a modified maximum ratio combining (M-MRC) to obtain an estimate of the transmitted symbols. Weights used in the combining method are derived from the channels coefficients between the cooperated BSs and the MS. Simulations show that the proposed scheme works well under frequency-selective channels and frequency non-selective channels. A gain of 9 dB and 6 dB in SIR is obtained under multipath fading and flat-fading channels, respectively.

Design Development of Fashion Cultural Products based on Convergence of International Exposition Yeosu and Regional Culture (여수세계박람회와 지역문화의 융합을 기반으로 한 패션문화상품 디자인개발)

  • Kim, Sun-Young
    • Journal of the Korean Society of Costume
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    • v.61 no.1
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    • pp.58-68
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    • 2011
  • With Expo 2012 Yeosu to be held in 2012, this study intends to propose designs for fashion cultural products into which the characteristics of local cultures of Yeosu are fused. Using symbols of Expo 2012 Yeosu and cultural symbols of Yeosu City as motifs, this study will develop patterns and then, apply them to neckties, handkerchiefs, and T-shirts. Adobe Illustrator CS2 and Adobe Photoshop CS2 will be used. This study developed basic motifs so that cultural resources using camellia, Odong Island, and the Turtle Ship, which represent Yeosu City, could be well harmonized with the topic of Expo 2012 Yeosu. This paper set three basic motifs of new formative images, using graphic images that were made by omission of forms, simplification, overlap, repetition, and calligraphy of the name of Yeosu holding the event. Each set motif was expanded to three motifs again through change, conversion, and mixture of colors, and three types of repetitive applied patterns were developed through revolution, symmetry, repetition, and reversal of each motif. The modern and refined image for neckties, to which the developed motif was applied, was made by directly applying the repetitive pattern of each motif or by making $45^{\circ}$ revolution. For handkerchiefs, revolution, enlargement, reduction, and gradation were applied to the motif so the pattern could be highlighted to the maximum and finally, a colorful image was developed. For T-shirts, three designs-a half-sleeved box type, a sleeveless round neckline type, and a sleeveless V-neckline tight type-were developed, through which availability of the design was increased. Through enlargement, reduction, revolution, and repetition of each motif, this paper layout the pattern on the whole part of a T-shirt, pursuing a decorative and casual image.

A Study on Efficiency Improvement and Optimization of Operating Characteristics of Pulsed $CO_2$ Laser System using Ring Blower (링 블로우를 이용한 펄스형 $CO_2$ 레이저 시스템의 효율 향상과 동작 특성에 관한 연구)

  • Kim, D.H.;Chung, H.J.;Park, S.J.;Joung, J.H.;Lee, D.H.;Kim, H.J.;Cho, J.S.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.05b
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    • pp.57-60
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    • 2000
  • In this paper, it is purpose to develop a pulsed $CO_2$ laser with stable output at pulse repetition rate range of 2 KHz. We used a IGBT as a switching device. The laser cavity was fabricated as an axial and water cooled type. It was used a ring blower to increase a cooling effect The laser performance characteristics as parameters, such as pulse repetition rate, gas pressure have been investigated. The experiment was done under 3 electrode-type instead of 2 electrode-type. To achieve 3 electrode-type, we used two pulse-transformers which is operated parallel. As a result, the maximum output was about 28 W at the total pressure of 20 Torr, the gas mixture $Co_2$:$N_2$:He=1:9:15 and the pulse repetition rate of 1300 Hz.

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Output characteristics of ac excited $CO_2$ laser as a adjusting a phase angle and frequency (위상각와 주파수 제어에 따른 상용주파 AC 여기 방식의 펄스형 $CO_2$ 레이저 전원장치 개발에 관한 연구)

  • Chung, Hyun-Ju;Kim, Do-Wan;Lee, Dong-Hoon;Kim, Joong-Mann;Kim, Mee-Je;Cho, Jung-Soo
    • Proceedings of the KIEE Conference
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    • 2000.07c
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    • pp.2098-2100
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    • 2000
  • We propose pulsed $CO_2$ laser below 30W by the AC(60Hz) switching control of leakage transformer primary which has some advantage of cost and size compared to a typical pulsed power supply. Pulse repetition rate is adjusted from 5Hz to 60Hz to control laser output. In this laser, a low voltage open loop control for high voltage discharge circuit is employed to avoid the HV sampling or switching and high voltage leakage transformer is used to convert rectified low voltage pulse to high voltage one. A ZCS(Zero Cross Switch) circuit and a PIC one-chip microprocessor are used to control gate signal of SCR precisely. The pulse repetition rate is limited by 60Hz due to the frequency of AC line and a high leakage inductance. The maximum laser output was obtained about 23W at pulse repetition rate of 60Hz, total gas mixture of $CO_{2}/N_{2}$/He = 1/9/15, SCR gate trigger angle 90$^{\circ}$, and total pressure of 18Torr.

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A Study on Efficiency Improvement and Optimization of Operating Characteristics of Pulsed $CO_2$ Laser System using 3 Electrode-type and Ring Blower (3전극 방식과 링 블로우를 이용한 펄스형 $CO_2$ 레이저 시스템의 효율 향상과 동작 특성에 관한 연구)

  • Kim, D.W.;Chung, H.J.;Park, S.J.;Lee, Y.S.;Lee, D.H.;Kim, H.J.;Cho, J.S.
    • Proceedings of the KIEE Conference
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    • 2000.07c
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    • pp.2101-2103
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    • 2000
  • In this paper, it is purpose to develop a pulsed $CO_2$ laser with stable output at pulse repetition rate range of 2 kHz. We used a IGBT as a switching device. The laser cavity was fabricated as an axial and water cooled type. It was used a ring blower to increase a cooling effect. The laser performance characteristics as parameters, such as pulse repetition rate, gas pressure have been investigated. The experiment was done under 3 electrode-type instead of 2 electrode-type. To achieve 3 electrode-type, we used two pulse-transformers which is operated parallel. As a result. the maximum output was about 28 W at the total pressure, of 20 Torr(the gas mixture $CO_2$:$N_2$:He=1:9:15 and the pulse repetition rate of 1300 Hz).

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Commercial frequency AC discharge magnetic stimulation operating characteristics (상용교류방전 자기자극장치의 동작특성)

  • Kim, Whi-Young
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.12
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    • pp.2685-2692
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    • 2009
  • We propose pulsed magnetic stimulation below 30W by the AC(60Hz) switching control of leakage transformer primary which has some advantage of cost and size compared to a typical pulsed power supply. Pulse repetition rate is adjusted from 5Hz to 60Hz to control magnetic stimulation output. In this magnetic stimulation, a low voltage open loop control for high voltage discharge circuit is employed to avoid the HV sampling or switching and high voltage leakage transformer is used to convert rectified low voltage pulse to high voltage one. A ZCS(Zero Cross Switch)circuit and a DSP & FPGA are used to control gate signal of SCR precisely. The pulse repetition rate is limited by 60Hz due to the frequency of AC line and a high leakage inductance. The maximum magnetic stimulation output was obtained about 33W at pulse repetition rate of 60Hz, total 40, 80, 120, $160^{\circ}$, SCR gate trigger angle $90^{\circ}$ and total output.