• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.670-675
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• 2006

The purpose of this study is the infiltration characteristics of soil cut-slope by the repetition & concentration rainfall. The maximum rainfall concentrate from June until September which is a rainy season in our country Stability analysis of soil cut-slopes has been conducted by limit equilibrium method on Seep/w and finite element method on Slope/w.

• Journal of Electrical Engineering and Technology
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• 제1권1호
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• pp.98-100
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• 2006

ZnO thin films were deposited at different repetition rates of 5 Hz and 10 Hz by pulsed laser deposition. X-ray diffraction (XRD) full widths at half maximum (FWHMs) of (002) ZnO peak in ZnO thin film deposited at 5 Hz and 10 Hz was 0.22 and $0.26^{\circ}$, respectively. The grain size of ZnO thin film deposited at 5 Hz was larger than that of 10 Hz. The variation of repetition rates did not have an effect on the optical property of ZnO thin films. The degradation of the crystalline quality and surface morphology in ZnO thin film deposited at 10 Hz resulted from supersaturation effect by decrease of time interval between a ZnO particle arriving on a substrate by laser shot and a ZnO particle arriving on a substrate by next laser shot.

• 한국컴퓨터산업학회논문지
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• 제2권8호
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• pp.1055-1062
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• 2001

본 연구에서는 1KHz 부근의 펄스 반복율을 가지는 경제적이고 컴팩트한 펄스형 $CO_2$ 레이저의 개발에 관해서 기술하였다. 고압 고주파 펄스 변압기와 수 십 KHz의 스위칭에 적합한 IGBT를 사용한 고압 펄스전원 장치를 레이저 공진기에 접목시켜 새로운 방식의 고반복 $CO_2$ 레이저 장치를 개발하였다. 전원장치에 사용된 2개의 IGBT를 정밀하게 제어하기 위해서 제어부에는 PIC 마이크로프로세서가 사용되었고 공진기는 수냉방식의 저속축류형으로 제작되었다. 완성된 장치의 펄스 반복율과 동작압력 그리고 레이저 매질 가스의 혼합비의 변화에 따른 레이저빔의 출력 특성실험을 통하여 가스 배압비 $CO_2$： $N_2$：He ＝ 1：9：15펄스 반복율 700 Hz, 동작압력 15 Torr에서 최대 레이저 출력 약 20.5 W, 최대 효율 약 8%를 달성하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 C
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• pp.1072-1074
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• 1999

In this study, it is the purpose to develope a cheap and compact pulsed $CO_2$ laser with pulse repetition rate range of 1 kHz. We used a IGBT switched power supply as a power supply, which is cheap and simple comparing to others. PIC one-chip microprocessor was used for precise control of a laser power supply on the control part. And the laser cavity was fabricated as an axial and water cooled type. The laser performance characteristics as various parameters, such as pulse repetition rate gas pressure, and gas mixture rate have been investigated. The experiment was done under the condition of total pressure of $CO_2:N_2$:He = 1.3:10, 1:1.5:5 1:9:15 from 6 Torr to 15 Torr and pulse repetition rate from 100 Hz to 900 Hz. As a result, the maximum average output was about 20.5 W at the total pressure of 15 Torr, the gas mixture $CO_2:N_2$:He = 1:9:15 and the pulse repetition rate of 700 Hz.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제48권11호
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• pp.730-734
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• 1999

In this study, it is the purpose to develope a cheap and compact repetitively pulsed $CO_2$ laser with pulse repetition rate range of 180 Hz. We used a SCR switched power supply as a high voltage pulsed supply, which is cheap and simple comparing to others. PIC one-chip microprocessor was used for precise control of a laser power supply on the control part. And the laser cavity was fabricated as an axial and water cooled type. The laser performance characteristics as various parameters, such as pulse repetition rate and gas pressure have been investigated. The experiment was done under the condition of total pressure of $CO_2, N_2$ and He from 4 Torr to 16 Torr and pulse repetition rate from 4 Hz to 180 Hz. As a result, the maximum average output was about 19.6W at the total pressure of 12 Torr and the pulse repetition rate of 180Hz.

• 한국체육학회지인문사회과학편
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• 제51권5호
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• pp.639-647
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• 2012

본 연구는 최근 3개월 동안 저항운동 경력이 없는 남학생 14명을 선정하여 2주간 체력을 안정화 시킨 후, 운동 강도(90, 75, 60% 1RM)와 세트 간 휴식시간(1, 3, 5분)을 조합한 9가지 운동 프로그램을 1주일 간격으로 적용하였다. 근기능 지표들(근수축력, 반복횟수, 총운동량)의 변화를 분석함으로써 적절한 운동 강도와 휴식시간의 효용성을 분석한 결과는 다음과 같다. 운동 강도별 세트 간 휴식시간에 따른 대흉근의 근수축력은 90, 60% 1RM 강도에서 유의하게 감소하였으나, 60% 1RM 강도에서 세트 간 5분 휴식 시에는 유의하게 증가하는 것으로 나타났고, 상완삼두근의 근수축력은 90% 1RM에서 세트 간 휴식시간에 따라 유의하게 감소하는 것으로 나타났다. 반복횟수와 총운동량은 세트 간 휴식시간에 따라 모든 강도에서 유의하게 감소하였으나, 강도가 낮아지고 휴식시간이 길어질수록 유의하게 증가하는 것으로 나타났다. 이상의 결과를 종합하면, 처음 저항운동을 시작하는 사람이나 비단련자의 경우에는 근기능 향상 및 정확한 자세와 기술을 습득할 수 있도록 운동 강도를 낮추거나 휴식시간을 길게 유지하는 방법이 효과적일 것이다.

• 전기학회논문지
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• 제64권8호
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• pp.1207-1211
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• 2015

Various laser systems have been widely used in almost all industrial technologies because they have high energy density, directivity and coherence. Recently the clinical application is becoming wider in medical parts such as incurable disease, diagnosis and so on. Generally, ruby laser beam has the greatest efficacy for removing tattoos, freckle and other skin problem. But current medical ruby laser system has the maximum repetition rate of 2Hz and optical output beam energy of 1J. Many medical doctors really want to have a high repetition ruby laser system because that can reduce the operation time. We investigated a new ruby laser system with high repetition rate of 4Hz using double cavities. Furthermore, we develop a new power supply system adopting zero voltage switching(ZVS) to minimize switching loss by LLC resonant converter designed as 2kW class.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권9호
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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 Magnetics
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• 제16권1호
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• pp.51-57
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• 2011

A power supply for magnetic-stimulation devices was designed via a control algorithm that involved a start current application based on a resonant converter. In this study, a new power supply for magnetic-stimulation devices was designed by controlling the pulse repetition frequency and pulse width. The power density could be controlled using the start-current-compensation and ZCS (zero-current switching) resonant converter. The results revealed a high-repetition-frequency, high-power magnetic-stimulation device. It was found that the stimulation coil current pulse width and that pulse repetition frequency could be controlled within the range of 200-450 ${\mu}S$ and 200-900 pps, respectively. The magnetic-stimulation device in this study consisted of a stimulation coil device and a power supply system. The maximum power of the stimulation coil from one discharge was 130 W, which was increased to 260 W using an additional reciprocating discharge. The output voltage was kept stable in a sinusoidal waveform regardless of the load fluctuations by forming voltage and current control using a deadbeat controller without increasing the current rating at the starting time. This paper describes this magnetic-stimulation device to which the start current was applied.

• 한국기계가공학회지
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• 제11권5호
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• pp.99-103
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• 2012

Presently, A glass is widely used in telecommunication system, optoelectronic devices and micro electro mechanical systems. Micro drilling of glass using the laser can save processing cost and improve the accuracy. This paper experiments micro drilling using KrF excimer laser on the pyrex glass of $500{\mu}m$ thickness. We have experiment to find out optimum laser machining conditions of micro drilling of glass and ablation depth and influence by processing parameter suc'h pulse repetition rate, energy density and number of pulses. Pulse repetition rate don't influence ablation depth at the micro drilling of pyrex glass. Energy density influence micro drilling of parallelism and maximum thickness that can be drilled. Ablation depth is most influenced by number of pulses.