• 한국초전도ㆍ저온공학회논문지
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• 제6권2호
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• pp.40-45
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• 2004

The experimental results of the G-M (Gifford-McMahon) type pulse tube refrigerators are presented in this paper. The pulse tube refrigerator, which has no moving parts at its cold section, is attractive in obtaining higher reliability, simpler construction, and lower vibration than any other small refrigerators. The objectives of this study are to develop the design technology of the G-M type pulse tube refrigerator and acquire its application methods for replacing G-M cryocooler. As a preliminary test, the refrigeration performances of the basic, orifice, and double inlet pulse tube refrigerators were investigated. The lowest temperature obtained in the one-stage pulse tube refrigerator was 34.4K and the refrigeration capacity at the optimum operation condition was 23W at 80K. And the lowest temperature of the second stage cold head in the two-stage pulse tube refrigerators was 18.3K and the refrigeration capacities at optimum condition were 0.45W at 20K and 20W at 80K, respectively. Finally, the lowest temperature obtained in the three-stage pulse tube refrigerator was 29.8K and the refrigeration capacity at the optimum operation condition was 1.3W for 40K and 5W for 70K.

• 대한한방부인과학회지
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• 제29권4호
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• pp.1-12
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• 2016

Objectives: The purpose of this study is to analyze the correlation between the pulse energy and hot flush in women who complain of climacteric syndrome. Methods: We analyzed the values of pulse energy on 78 of perimenopausal and postmenopausal women. The symptoms of patients were assessed by Kupperman’s index (KI) and Menopause Rating Scale (MRS). Statistical analysis was performed by Spearman correlation coefficient and student T-test, using SPSS 18.0 for window program. Results: The results were as follows. 1. There were no statistically significant relation between pulse energy of left Cheok subtracted from left Chon and KI, MRS hot flush score. 2. When divided depending on MRS hot flush score, There were no statistically significant differences on pulse energy. Conclusions: The results suggest that there is no correlation between hot flush score and pulse energy.

• 대한한방부인과학회지
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• 제30권4호
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• pp.77-88
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• 2017

Objectives: The purpose of this study is to analyze the characteristics of the pulse energy in women with PCOS (Polycystic ovary syndrome) compared with women who have a regular menstrual cycle. Methods: We analyzed the values of pulse energy on 20 patients with PCOS as an experimental group and 40 patients with regular menstrual cycle as a control group. Control group was divided into 20 women with follicular phase and 20 women with luteal phase respectively. Statistical analysis was performed using SPSS/Win 18.0, one way ANOVA and Tukey HSD. Results: The results were as follows. 1. The mean pulse energy of the Right Chon was significantly increased compared with those of the Left Kwan and the Right Kwan among PCOS group. 2. There were no statistically significant pulse energy among control groups. Conclusions: The pulse energy of Lung is bigger than that of Spleen and Liver in PCOS patients compared with women who have a regular menstrual cycle.

• 제어로봇시스템학회논문지
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• 제18권4호
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• pp.371-374
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• 2012

DC/DC switching power converters produce DC output voltages from different stable DC input sources regulated by a bi-polar transistor. The converters can be used in regenerative braking of DC motors to return energy back in the supply, resulting in energy savings for the systems containing frequent stops. The voltage mode DC/DC converter is composed of a PWM (Pulse Width Modulation) controller, a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), an inductor, and capacitors, etc. PWM is applied to control and regulate the total output voltage. It is shown that the output of DC/DC converter depends on the variation of threshold voltage at MOSFET and the variation of pulse width. In the PWM operation, the missing pulses, the changes in pulse width, and a change in the period of the output waveform are studied by SPICE (Simulation Program with Integrated Circuit Emphasis) and experiments.

• 한국광학회:학술대회논문집
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• 한국광학회 2000년도 하계학술발표회
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• pp.18-19
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• 2000

In this paper, packet error rates of an all-optical packet switching node, which uses a fiber-optic delay-line matched filter as the optical packet header processor, has been calculated for the various optical pulse shapes.

• 한국전자파학회논문지
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• 제30권4호
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• pp.307-313
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• 2019

Ka-대역 밀리미터파 복합모드 탐색기에 적용할 수 있는 진행파관 증폭기(traveling wave tube amplifier: TWTA)는 고전압생성부(high voltage power supply: HVPS), 변조부(grid modulator), 제어부(command & control), 고조파부(RF assembly)로 구성되는 고출력 펄스형 송신기이다. 펄스 반복 주파수(pulse repetition frequency: PRF)와 전원공급기 스위칭 주파수가 동기/가변되어 -17.9 kV 고전압을 생성하는 고전압 전원 공급기와 RF 펄스 변조를 위한 고속 그리드 스위칭 변조기를 설계하였다. 체적이 3.18 L로 소형화로 제작된 TWTA는 그리드 on/off 신호의 상승/하강시간이 최대 18.5 ns 이하 고속펄스 스위칭 특성을 가지고, 첨두전력은 564.9 W 이상으로 고출력 성능을 보였다. 또한 PRF와 PRF/2 범위 내에서 -68.4 dBc 이하의 우수한 불요파 성능을 확인하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 추계학술대회 논문집
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• pp.164-165
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• 2001

An IGBT driver for serially connected pulse switching IGBTS was contructed and tested. The IGBT driver has ten output pulses with 1 ${\mu}ysec$ pulse width Its pulse repetition-rate can adjusted from 0 to 20 kHz. The output pulses was insulated from 10 kV high voltage by a pulse transformer. Their voltage amplitude are 18 V, voltage rising time 250 nsec., and voltage falling time 200 nsec when IGBT gates with 12 nF input capacitance are connected.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 I
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• pp.242-245
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• 2003

This paper introduces a new algorithm of pulse generation and detection for UWB communication system. The existing UWB systems using Gaussian pulse have some difficulties to cope with bandwidth limitation and frequency transition. Moreover. the system sensitivity to channel noise has made the processes of acquisition and tacking difficult. in this paper, we introduce a new pulse generation method which is able to control the bandwidth and center frequency applying modulation method. thus could improve the detection performance of receiving algorithm. Also, we made a system to search maximum perk by applying the proposed algorithm and consequently could guarantee the correct detection. By the result of simulation, when accumulate 10 times at every 2dB band shifting from 0 to 18dB on AWGN channel, we could confirm the proposed method has 97.4% PDR(Pulse Detection Rate) and 1.868% FAR(False Alarm Rate) performance at 4dB SNR and 15% transmission power threshold level.

• 대한한의학회지
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• 제18권1호
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• pp.267-277
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• 1997

Experiments were performed to determine the effects of the Oyacksunkisan(烏藥順氣散) and Kamioyacksunkisan(加味烏藥順氣散) liquid extract on the hypertension and the pulse rate in Sprague-Dawley rat(SDR) and Spontaneous Hypertensive rats(SHR). The results were obtained as follows ; 1. Blood pressure was significantly decreased firstday and 11th day after administration of Oyacksunkisan extract and pretreatment of phentolamine. 2. Blood pressure and pulse rate were regulated first day after administration of Kamioyacksunkisan and blood pressure was significantly decreased after pretreatment of clonidine and phentolamine. 3. Oyacksunkisan and Kamioyacksunkisan didn't show any significant changes of blood pressure and pulse rate after pretreatment of prdpranolol, hydralazine and verapamil From the above result, it was concluded that Oyacksunkisan(烏藥順氣散) and Kamioyacksunkisan(加味烏藥順氣散) could be applied effectively to the hypertension.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.129-132
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• 2004

This study concerns the new strength equation of concrete by ultrasonic pulse velocity test. There are not only few estimate strength equations of concrete by ultrasonic pulse velocity test, but also many problems to apply them because of time, cost, easiness, structural damage, reliability and so on. For this study, there performed a series of test and proposed equations as follows; $$Linear\;:\;f_{kc}=65.43Vp-207.18\;r^2=80.8\%$$ $$Quadratic\;:\;f_{ck}=42.35Vp^2-250.71Vp+378.8\;r^2=83.7\%$$ here, fck : Estimated compressive strength of concrete by MPa Vp: Ultrasonic Pulse Velocity of concrete by km/sec.