• 한국자기학회지
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• 제21권2호
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• pp.48-51
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• 2011

본 논문에서는 짧은 전류 펄스를 이용한 미소자기 소자에서의 전류 유도 자화 반전에 대한 매크로 스핀 시뮬레이션 연구를 수행하였다. 자화 반전 전류 분포에 있어서 에너지 장벽이 미치는 효과에 특별히 주목하였다. 자화 반전 전류의 크기 및 분포는 전류 펄스 폭의 감소에 따라 증가했다. 여기서 긴 전류 펄스 폭 영역에서는 에너지 장벽과 자화 반전 전류 분포 사이의 관계가 아레니우스-닐 법칙에 의해 서술된다. 하지만 짧은 전류 펄스 폭의 영역에서는 이 관계가 풀리지 않은 채로 남아있다. 이는 짧은 전류 펄스로 인한 자화 반전이 열적 활성화에 의해서가 아닌 세차 운동에 의해 좌우되기 때문이며, 이를 해결하는 데에 있어서 어려움이 발생한다. 그러므로 포커-플랑크 방정식을 풀어서 짧은 전류 펄스 영역에서의 자화 반전에 대한 정확한 공식을 얻어내는 것이 필요하며 이를 통해 짧은 전류 펄스 영역에서의 자화 반전 양상을 이해 할 수 있을 것으로 본다.

• 전자공학회논문지D
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• 제34D권10호
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• pp.85-92
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• 1997

For a InGaAsP buried - heterostructrue $1.3\mu\textrm{m}$ LD with fabry-perot cavity structure, the procedures of ultra-short optical pulse genration ar eanalyzed by simulating the rate equations. Investigting the effects of injected current pulse parameters such as bias $J_b$, pulse width $T_d$ and pulse amplitude $J_p$ on the generated optical pulses, we derive the optimum conditions to obtain a single optical pulse with strong peak value. We also observe that the repetition rate of current pulses needs to be restricted under a certain threshold to generate a train of single optical pulses, and that the period doubling phenomenon takes place by increasing the repitition rate.

• 전기의세계
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• 제29권5호
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• pp.321-328
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• 1980

The Q-switching oscillator of TE $M_{00}$ mode was constructed in order to improve the properties of energy focusing and amplification, and prevent laser materials from breakdown. The Q-switching was done by means of electro-optical effect using Glan prism and KDP Pockels cell. Sharp laser pulse of risetime-1 ns and variable pulse width 2-10 ns was obtained from Q-switching laser pulse by PTM method using a laser triggered spark gap (LTSG), Glan prism and Pockels cell. A single ultra-short pulse (picosec order in pulse width) was obtained from mode-locked pulse train in combination of a mode-locked oscillator using saturable dye cell with pulse shaping system using PTM method.d.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1990년도 추계학술대회 논문집 학회본부
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• pp.287-290
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• 1990

The paper describes the correction of the switching dead times avoiding a bridge leg short circuit in pulse width modulated voltage sorce inverters. The co consequences on AC variable speed drives with synchronous and asynchronous motors are described by harmonic analysis and by computer simulation.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2004년도 춘계종합학술대회
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• pp.339-341
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• 2004

Self Q-switching에 의한 분포궤환 색소레이저(DFDL: Distributed Feedback Dye Laser)로부터 80uJ의 단일 극초단 펄스를 얻고, 이를 2단의 증폭기와 betune cell에 의한 3단 증폭으로 높은 출력을 얻은 후 BBO를 사용, 자외선 영역의 제 2고조파를 얻었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.159-161
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• 2007

$CO_2$ laser sees that is most suitable to get this effect through minimum formation damage and advantage that is root enemy of effect that happen in minimum cellular tissue depth of 0.1mm is stable living body organization or internal organs institution. Formation damage by ten can be related in formation's kind or energy density, length of evaporation time. If shorten evaporation time, surroundings cellular thermal damage 200 - because happen within 400ums laser beam in rain focus sacred ground surroundings cellular tissue without vitiation me by evaporation Poe of very small floor as is clean steam can. Application is possible to vulva cuticle cousins by a paternal aunt quantity, uterine cancer, cuticle tumor by laser system that $CO_2$ laser gets into standard in obstetrics and gynecology application. Because effect that super pulse output is ten enemies of laser if uniformity one pulse durations are short almost is decreased, most of all pulse module special quality of pulse style $CO_2$ laser for obstetrics and gynecology mode stabilization by weight very, in this research to get into short pulse duration and higher frequency density, do switching by high frequency in DC-DC Converter output DC's ripple high frequency to be changed, high frequency done current ripple amount of condenser for output filter greatly reduce can. Ripple of output approximately to Zero realization applying possible inductor realization through a special quality experiment do.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.55-57
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• 2007

$CO_2$ laser sees that is most suitable to get this effect through minimum formation damage and advantage that is root enemy of effect that happen in minimum cellular tissue depth of 0.1mm is stable living body organization or internal organs institution. Formation damage by ten can be related in formation's kind or energy density, length of evaporation time. If shorten evaporation time, surroundings cellular thermal damage 200 - because happen within 400ums laser beam in rain focus sacred ground surroundings cellular, tissue without vitiation me by evaporation Poe of very small floor as is clean steam can. Application is possible to vulva cuticle cousins by a paternal aunt quantity, uterine cancer, cuticle tumor by laser system that $CO_2$ laser gets into standard in obstetrics and gynecology application. Because effect that super pulse output is ten enemies of laser if uniformity one pulse durations are short almost is decreased, most of all pulse module special quality of pulse style $CO_2$ laser for obstetrics and gynecology mode stabilization by weight very, in this research to get into short pulse duration and higher frequency density, do switching by high frequency in DC-DC Converter output DC's ripple high frequency to be changed, high frequency done current ripple amount of condenser for output filter greatly reduce can. Ripple of output approximately to Zero realization applying possible inductor realization through a special quality experiment do.

• 디지털콘텐츠학회 논문지
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• 제10권2호
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• pp.199-207
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• 2009

Q-스위칭은 셔터나 다른 광학소자를 레이저 광 공진기 내에 넣어 광이 공진기 내에서 발진하는데 손실을 유발하고, 충분한 반전분포가 활성 매질 내에서 생성되면 순간적으로 셔터를 열어 공진기 내에 축적된 에너지가 매우 강한 빛으로 방출되게 하는 것이다. 이와 같이 Q-스위칭은 레이저 공진기의 Q--factor를 감소시켰다가 갑자기 증가시키는 것이다. 레이저 Q-스위칭의 방법에는 mechanical switching 방법, electro-optic switching 방법, switching by saturable absorber 방법, acousto-optic switching 방법 등 크게 4가지가 쓰이고 있다. 이들 중 전기광학적인 효과에 의한 전기적인 전환은 짧은 펄스폭의 Q-스위칭 펄스를 생성할 수 있기 때문에 널리 사용되고 있다. 따라서, 전기광학효과의 특성을 가진 Pockel cell은 Q--switch로 사용하기 적합한 것으로 알려져 있다. 본 연구에서는 포켈스 셀 Q-스위치용 구동 장치를 스위칭 소자인 FET와 PIC 마이크로프로세서 및 펄스 트랜스로 설계, 제작하고, 펄스형 Nd:YAG 레이저 시스템에 적용하여 Q-스위치의 동작 특성을 조사, 연구하였다. 또한, 이 Q-스위치를 통하여 출력된 Nd:YAG 레이저 빔의 측정치를 이론적 계산에 의해 구해진 예상치와 비교하여 Q-스위칭 된 레이저 빔의 특성을 분석하였다.

• Journal of Power Electronics
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• 제5권4호
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• pp.247-256
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• 2005

In order to harvest power in an efficient manner from a micro piezoelectric (PZT) device for charging the battery of a remote system, a new AC/DC resonant pulse power converter is proposed. The proposed power converter has two stages in the power conversion process. The first stage includes N-type MOSFET full bridge rectifier. The second stage includes a boost converter having an N-type MOSFET and a P-type MOSFET. MOSFETs work in the $1^{st}$ or $3^{rd}$ quadrant region. A small inductor for the boost converter is assigned in order to make the size of the power converter as small as possible, which makes the on-interval of the MOSFET switch of the boost converter ultimately short. Due to this short on-interval, the parasitic junction capacitances of MOSFETs affect the performance of the power converter system. In this paper, the performance of the new converter is analytically and experimentally evaluated with consideration of the parasitic capacitance of switching devices.

• Journal of Power Electronics
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• 제13권1호
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• pp.51-58
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• 2013

This paper proposes the power conversion mechanism of a bailer-charge-transfer zero-current-switching (CT-ZCS) circuit. The operation modes are analyzed and researched using state trajectory equations. The topology of CT-ZCS based on soft-switching inverters offers some merits such as: tracking the input reference signal dynamically, bearing load shock and short circuit, multiplying inverter N+1 redundancy parallel, coordinating power balance for easy control, and soft-switching commutation for high efficiency and large capacity. These advantages are distinctive from conventional inverter topologies and are especially demanded in AC drives: new energy generation and grid, distributed generation systems, switching power amplifier, active power filter, and reactive power compensation and so on. Prototype is manufactured and experiment results show the feasibility and dynamic voltage-tracking characteristics of the topology.