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Study of Multichannel Pseudo-spark Switch for High-voltage and High-current (고전압 대전류 Multichannel Pseudo-spark 스위치 연구)

  • Park, S.S.;Han, Y.J.;Kim, S.H.;Kwon, Y.K.;Kim, S.H.;Park, Y.J.;Nam, S.H.
    • Proceedings of the KIEE Conference
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    • 2002.07c
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    • pp.1859-1861
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    • 2002
  • This paper attempts to discuss the pseudo-spark which is developed for high voltage and high current. The pseudo-spark switch is on the basic of the Paschen's law. The pseudo-spark switch fabricates the glass chamber. The pseudo-spark switch consists of hollow cathode, hollow anode, and trigger. The pseudo-spark switch is operated at the voltage of 20 kV and the pressure range of 2080 mtorr with He-gas. The switching current of the pseudo-spark switch was measured as 65 kA, and the duration of the pulse was about 100 μs. This paper describes the results of tests and the characteristics of the switch.

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Development of surface electrode type electrical stimulator or supporting walk function in foot drop patients (족하수 환자에서의 보행기능 보조를 위한 표피 자극형 전기자극기 개발)

  • Lim, S.K.;Jeong, H.C.;Kim, K.G.;Jin, D.B.;Park, B.R.
    • Proceedings of the KOSOMBE Conference
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    • v.1997 no.11
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    • pp.9-13
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    • 1997
  • The present study was designed to develop the functional electrical stimulation system in order to restore motor function of paralytic patients. We attempt to establish adequate stimulus parameters for the recovery of work unction in lower limb paralysis patients and to develop the electrical stimulation system, which is effective to protect foot drop in these patients. In our animal and human experiment, adequate stimulus condition for surface electrode on the lower limb were 0.2-0.3ms at the duration and 50 Hz, which contain 600Hz train pulse. This parameter has efficiently prevented the foot drop from lower limb paralysis, decreased muscle fatigue and induced powerful contraction of lower limb muscle.

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Subarachnoid Morphine for Perianal Postoperative Pain Control (미양(微量) Morphine 지주막하(蜘蛛膜下) 주입(注入)에 의(依)한 항문각위술후(肛門脚圍術後) 제통효과(除痛效果)에 대(對)한 임상연구(臨床硏究))

  • Rhim, Hwa-Taeg;Lee, Yeong-Sik;Oh, Hung-Kun
    • The Korean Journal of Pain
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    • v.1 no.1
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    • pp.98-102
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    • 1988
  • In order to control the pain after hemorrhoidectomy and anal fistulectomy, 6 mg of 0.5% hyperbaric tetracaine without(control, group I) or wilt 0.3 mg(group II) or 0.5 mg (group III) of 0.1% morphine was injected with a 22 gauge spinal needle into the subarachnoid space through L 3-4 interspace of patients in lateral position. About 30 minutes in Fowler' sposition after injection, operation was performed in lithotomy position. All the patients who ha4 morphine showed remarkable relief of postoperative pain for an average of 27 hours. However, the dosage(0.3 or 0.5 mg) of morphine administered did not affect the duration of pain relief. Blood pressure, pulse rate and pupil size were unchanged in all patients. Dysuria after block developed for on average of 5,6, 13.2 and 14.6 hours in group I, II and III respectively. Most of these cases required urethral catheterization. Minor complications such as nausea, vomiting, itching, fever, burning sensation and paresthesia were observed 16.7, 20 and 20% of cases in group I, II and III respectively; however, no treatment was required.

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Simmyung Laser System and Study on the X-ray Generation (신명 레이저와 X-선 발생 연구)

  • Kong, Hong-Jin;Han, Ki-Gwan;Kim, Nam-Seong;Kim, Hyun-Soo;Um, Ki-Young;Park, Jong-Rak;Lee, Jae-Youg;Shin, Yun-Sup;Han, Ki-Ho
    • Proceedings of the Optical Society of Korea Conference
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    • 1995.06a
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    • pp.185-189
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    • 1995
  • A high-power Nb:glass laser system(Simmyung I) has been contructed and tested. In this system, we used a Nb:YLF laser as a master oscillator, a 4-pass amplifier for pre-amplification, 5 stages of rod amplifiers, and spatial filtering and image reaying usits. The system has demonstrated in excess of 80J(2TW) with 40 psec(FWHM) pulse duration. Output energy, gain and spatial were measured at each amplification stage. With this laser system a preliminary X-ray generation experiment was performed. Pinhole images, X-ray diode signals and X-ray speriment were obtained for the irradiated target of copper. Detailed descriptions of the system performance and the X-tay generation experiment are presented.

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Stability of Triplet NbTi Cable-In-Conduit Conductor (NbTi 관내 3연선 도체의 안정성)

  • Jang, H.M.;Oh, S.S.;Ha, D.W.;Ha, H.S.;Bae, J.H.;Kim, S.C.;Ryu, K.S.;Wang, Q.L.
    • Proceedings of the KIEE Conference
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    • 1998.07a
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    • pp.82-84
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    • 1998
  • The normal zone propagation velocity and minimum quench energy (MQE) of cable-in-conduit conductors (CICC) has been investigated at the different background magnetic fields and supercritical helium pressures. The sample CICC of 2 m in length was fabricated with triplet NbTi/Cu strands inserting into a round stainless-steel tube. The heat pulse disturbance with duration time about 400 ms was acted on the center region of the CICC to quench the strands. The normal zone propagation velocity increased with operating current of the CICC. The measured velocity with respect to operation current could be fitted with numerical results.

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A Comparative Study of Glottal Data from Normal Adults Using Two Laryngographs

  • Yang, Byung-Gon;Wang, Soo-Geun;Kwon, Soon-Bok
    • Speech Sciences
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    • v.10 no.1
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    • pp.15-25
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    • 2003
  • A laryngograph was developed to measure the open and closed movements of vocal folds in our laboratory. This study attempted to evaluate its performance by comparing its glottal data with that of the original laryngograph. Ten normal Korean adults Participated in the experiment. Each subject produced a sustained vowel /a/ for about five seconds. This study compared f0 values, contact quotients of the duration of closed vocal folds over one glottal pulse, and area quotients of the closed over open vocal folds derived from glottal waves using both the original and new laryngographs. Results showed that the mean and standard deviation of the two laryngographs were almost comparable with a correlation coefficient 0.662 but minor systematic shift below those of the original laryngograph was observed. The absolute mean difference converged into 1 Hz, which indicates a possibility of adopting some threshold of rejecting inappropriate pitch values beyond a threshold value. The contact quotient of the normal subjects came out slightly over the 50% in a citation speech. Finally, the area quotient converged into 1. We will pursue further studies on the abnormal patients in the future.

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Observations of Pulsed Bi-polar Discharges in Saline Solutions with Pin to Plate Electrodes

  • Shin, Bhum Jae;Seo, Jeong-Hyun;Collins, George J.
    • Journal of Electrical Engineering and Technology
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    • v.13 no.5
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    • pp.2011-2016
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    • 2018
  • In this study, we have been investigated pin to plate pulsed bi-polar discharges in saline solutions, where bubble generation occurs. We integrate basic I-V-t electrical characteristics with the ICCD shadowgraph images, and finally instant and time averaged I-V waveforms. We observed that the bubble formation phase dynamics is quite different corresponding to the polarity applied to the pin electrode. When the pin electrode is a cathode, the bubble tends to be periodically detached from the pin electrode and the numerous tiny voltage spikes occur related to the electron emission from a pin cathode casing via, we judge from, direct dissociation of water molecules by energetic electrons. On the contrary, the bubble tends to stick to the pin electrode, when the pin electrode is anode; the bubble grows in size throughout the pulse duration. The dynamic electrical characteristics relative to the applied polarity of a pin electrode are presented and discussed by analysis of time averaged I-V waveforms.

Temperature Control of the Aluminum Plate with Pottier Module by PWM Current Control (PWM 전류제어와 펠티어 소자를 이용한 알루미늄 판의 온도 제어)

  • Pang Du-Yeol;Kwon Tae-Kyu;Lee Seong-Cheol
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.10a
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    • pp.897-900
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    • 2005
  • This paper presents temperature control of aluminum plate using Peltier module. As one of the thermoelectric effect, Peltier effect is heat pumping phenomena by electric energy. So if current is charged to Peltier module, it absorbs heat from low temperature side and emits heat to high temperature side. In this experiment, Peltier module is used to control the temperature of small aluminum plate with heating and cooling ability of Peltier module with current control and fan On/OFF control. And current control of Peltier module was accomplished by PWM method. As a results of experiments, it takes about 125sec to control temperature of aluminium plate between 30Cand70C and about 70sec between 40Cand60C, in ambient temperature 29C while operating cooling fan only while cooling duration. Future aim is to realize more rapid temperature control and develop SMHA(special metal hydride actuator) by using Peltier module as a heating and cooling source.

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Microfabrication by Localized Electrochemical Deposition Using Ultra Short Pulses (초단펄스 응용 전해증착에 의한 마이크로 구조물 제작)

  • 박정우;류시형;주종남
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.11
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    • pp.186-194
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    • 2004
  • In this research, microfabrication technique using localized electrochemical deposition (LECD) with ultra short pulses is presented. Electric field is localized near the tool tip end region by applying a few hundreds of nano second pulses. Pt-Ir tip is used as a counter electrode and copper is deposited on the copper substrate in 0.5 M CuSO4 and 0.5 M H2SO4 electrolyte. The effectiveness of this technique is verified by comparison with LECD using DC voltage. The deposition characteristics such as size, shape, surface, and structural density according to applied voltage and pulse duration are investigated. The proper condition is selected from the results of the experiments. Micro columns less than 10 μm in diameter are fabricated using this technique. The real 3D micro structures such as micro pattern and micro spring can be fabricated by this method. It is suggested that presented method can be used as an easy and inexpensive method for fabrication of microstructure with complex shape.

Experimental Investigation of a High-repetition-rate Pr3+:YLF Laser with Single-frequency Oscillation

  • Dai, Weicheng;Jin, Long;Dong, Yuan;Jin, Guangyong
    • Current Optics and Photonics
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    • v.5 no.6
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    • pp.721-729
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    • 2021
  • We demonstrate a Pr3+:YLF 639.7-nm laser with single-frequency output based on the Q-switched pre-lase technology, pumped by a fiber-coupled GaN blue laser diode. The pre-lase technology is realized by the step-type loss of the acousto-optical Q-switched device. The conclusions of the theoretical research are verified experimentally. The mode-suppression ratio was 44 dB at the single-frequency laser output. Detection by interferometer verified the realization of the stable single-frequency laser. In addition, the emission spectrum had a linewidth of 139.9 MHz, measured by Fabry-Perot interferometer. The single-frequency laser's single-peak power was over 19.7 W with 98.8-ns pulse duration, obtained under an absorption power of 1.74 W.