• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2198-2200
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• 1999

In this study, it is the purpose to study about design and manufacture of a pulse transformer for using in pulse generator and a pulse laser system. In this experiment, a ferite core in transformer instead of air core is used. The performance of the transformer is demonstrated by a voltage pulse waveform according to inductance of primary and secondary in transformer. As a result, the voltage pulse width is increased as increasement of inductance in transformer. And the voltage rate between primary and secondary is almost same with rate of inductance between primary and secondary.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1729-1731
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• 2003

Recently many solid-state laser systems were widely used in the medical applications. So it is necessary to study various optimal laser parameters for adopting new medical treatments. Alexandrite laser using switching mode power supply has designed and experimented to adjust a pulse repetition rate by PIC one-chip microprocessor. The fundamental results have been obtained during the first financial year in 2002. We will be able to find out the optimal hair removal characteristics by the repetitive experiments of Alexandrite laser as the parameters such as pulse repetition rate, pulse width, and pulse energy etc.

• Korean Journal of Acupuncture
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• v.26 no.4
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• pp.13-22
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• 2009

Objectives : Informations on pulse diagnosis in literature are based on diagnosing pulse waveforms on supine posture. However, today's pulse waveforms are measured on various postures for the convenience of patients or doctors. For objective measurement, the effect of posture on the pulse waveforms should be considered. The objective of this study was to find posture-related changes in the radial pulse waveforms. Methods : We used an instrument, DMP-3000(DAEYOMEDI Co., Ansan, Korea), measuring radial pulse waveforms noninvasively by tonometric method. 25 male subjects participated in the trial. Before measuring radial pulse waveforms subjects had rest for 5 min. The pulse waveforms were measured on the left wrist. Each subject underwent this course on the supine, sitting, and standing posture. We analyzed pulse waveforms with Height-parameters, Time-parameters, Energy, and Elastic rate. Results : Height-parameters(h1~h5) on the supine posture were bigger than those on the sitting and standing posture. In case of Time-parameters, the parameters making up systolic time decrease in order of on standing, sitting, and supine position. However, systolic time and diastolic time didn't have any changes. Energy of pulse was the biggest on supine posture and Elastic rate on standing posture. Conclusions : In this study we found that posture changes affect radial pulse waveforms. For quantification of the changes, more trials should be done. After analyzing much data we might apply parameters of pulse waveforms changed by posture. Also, we might diagnose special disease with properties of pulse waveforms by posture.

• Current Optics and Photonics
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• v.1 no.3
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• pp.203-206
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• 2017

We report a passive Q-switching of an all-fiber erbium-doped fiber laser delivering high pulse energy by using a high quality single-walled carbon nanotube saturable absorber (SWCNT-SA). A side-polished fiber coated with the SWCNT is employed as an in-line SA for evanescent wave interaction between the incident light and the SWCNT. This lateral interaction scheme enables a stable Q-switched fiber laser that generates high pulse energy. The central wavelength of the Q-switched pulse laser was measured as 1560 nm. A repetition rate frequency of the Q-switched laser is controlled from 78 kHz to 190 kHz by adjusting the applied pump power from 124 mW to 790 mW. The variation of pulse energy from 51 nJ to 270 nJ is also observed as increasing the pump power. The pulse energy of 270 nJ achieved at maximum pump power is 3 times larger than those reported in Q-switched all-fiber lasers using a SWCNT-SA. The tunable behaviors in pulse duration, pulse repetition rate, and pulse energy as a function of pump power are reported, and are well matched with theoretical expectation.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.514-517
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• 1996

Zero current switching(ZCS) series resonant converter is used to control laser power density in a pulsed Nd:YAG laser power supply. The high power and high repetition rate paused Nd:YAG laser is designed and fabricated to control current pulse width and pulse repetition rate in the double elliptical laser oscillator. In order to find out operational characteristics of pulsed Nd:YAG laser, the electrical properties of driving power supply and laser output power are investigated and experimented by changing of the current pulse width from 200uS to 350uS(step 50uS) and pulse repetition rate range of 500pps(pulse per second) to 1150pps. From that result, we obtaind maximum efficiency of 1.83% and maximum laser output or 220W at the condition of 350 uS and 1150pps with one Nd:YAG rod), and obtained that of more than 400W with two laser head connecting series.

• Journal of the Optical Society of Korea
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• v.17 no.5
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• pp.357-361
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• 2013

A regenerative Er-doped fiber amplifier system for a high-repetition-rate optical pulse train is investigated for the first time. A signal pulse train with a wavelength tuning range of 18 nm is produced by a passive mode-locked fiber laser based on a nonlinear polarization rotation technique. In order to realize the amplification, an optical delay-line is used to achieve time match between the pulses' interval and the period of pulse running through the regenerative amplifier. The 16 dB gain is obtained for an input pulse train with a launching power of -30.4 dBm, a center wavelength of 1563.4 nm and a repetition rate of 15.3 MHz. The output properties of signal pulses with different center wavelengths are also discussed. The pulse amplification is found to be different from the regenerative amplification system for CW signals.

• Women's Health Nursing
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• v.9 no.2
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• pp.138-151
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• 2003

Purpose: In the study effects of San-Yin-Jiao (SP6) acupressure on anxiety and pulse during labor, and on neonatal status were examined. Method: The design was a randomized controlled clinical trial with a double-blind method. Data were collected before (pre) and after (post) treatment using structured questionnaire, anxiety scale, pulse rate, umbilical vein pH and Apgar scores. The experimental group received SP6 acupressure for the duration of each uterine contraction over a period of 30 minutes, but the control group received SP6 touch. Results: The anxiety scores between the two groups increased, but the increase was less in the SP6 acupressure group and the difference was statistically significant (p=0.019). Maternal pulse rate was not significantly different immediately after treatment (p=0.711), at 30 and at 60 minutes (p=0.140 ; p=0.108), but while the SP6 acupressure group had a stable pulse, the SP6 touch group showed an increased rate. There was no significant difference between the two groups for umbilical vein pH (p=0.124), and neonatal Apgar score at one and five minutes (p=0.387 ; p=0.979). Conclusion: These findings strengthen the belief that SP-6 acupressure can be used to relieve anxiety during labor with no side effects to either mother or baby.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.9
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• pp.541-545
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• 2000

We propose a pulsed $CO_2$laser below 30W by the AC(60Hz) switching control of leakage transformer primary which has some advantages of cost and size compared to a typical pulsed power supply. Pulse repetition rate is adjusted from 5 Hz to 60 to Hz control laser output. In this laser a low voltage open loop control for high voltage pulse discharge circuit is employed to aviod the Hv sampling or switching and high voltage leakage transformer is used to convert low voltage pulse rectified from AC to high voltage one. A ZCS(Zero Crossing Switch) circuit and a PIC(programble 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 leadkage inductance. The maximum laser output was about 23 W at pulse repetition rate of 60Hz total gas mixture of $CO_2$ : $N_2$ : He=1: 9: 15 and total pressure of 18 Torr

• Journal of Electrical Engineering and Technology
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• v.8 no.2
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• pp.376-384
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• 2013

With the continuous aging of the populations in developed countries, the medical requirements of the aged are expected to increase. In this paper, a ring-type pulse oximeter finger sensor and a 24-hour ambulatory heart rate monitoring system for the aged are presented. We also demonstrate the feasibility of extracting accurate heart rate variability measurements from photoelectric plethysmography signals gathered using a ring-type pulse oximeter sensor attached to the finger. We designed the heart rate sensor using a CPU with built-in ZigBee stack for simplicity and low power consumption. We also analyzed the various distorted signals caused by motion artifacts using a FFT, and designed an algorithm using a least squares estimator to calibrate the signals for better accuracy.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.6
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• pp.1194-1199
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• 2009

Heart rate may be a very important parameter in human health. To extract heart rate, the electrocardiogram(ECG) is commonly used. But the ECG acquisition procedure is very complex. On the other hand, the acquisition of pulse wave or photoplethysmogram(PPG) is very easy. However, the peak of PPG is not so sharp as ECG. This study tries to enhance the performance of peak detection in PPG signal. The method uses the average slopes around the main peak. The crossing point of the increasing and the decreasing slopes is selected as the peak point of heart rate period. The proposed method showed smoothed heart rate graph and reduced irregularity in heart rate values.