• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 하계학술대회 논문집
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• pp.196-197
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• 2010

This paper investigates a high performance converter topology for hydrogen gas generation electrolysis system. The proposed converter topology consists of full-bridge inverter, medium frequency transformer, and diode rectifier. Hydrogen gas generation electrolysis process considered in the paper is analyzed and characterized by its equivalent circuit. The electrolysis cell is modeled as effective resistance, capacitance, inductance, and internal emf voltage source. The proposed converter topology provides enhanced efficiency of hydrogen gas generation process under the operating condition of dc output voltage with high frequency ripple on it. The high performance operation of proposed converter is confirmed through the simulation with the electrolysis cell considered in the equivalent circuit model.

• 전자공학회논문지D
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• 제35D권12호
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• pp.12-20
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• 1998

평행평판도파관에 유한한 개수의 슬릿으로 이루어진 비균일한 누설파 구조를 송(수)신 누설파 안테나와 격자 결합기의 관점에서 해석하였다. 특정한 복소 전파상수분포를 갖는 누설파 구조를 구성하기 위하여 누설파 구조를 따라 주기와 슬릿의 폭을 함께 변화시켰다. 가우스, 균일, 코사인, 코사인 제곱, Taylor 분포와 같은 다양한 전원(등가 자계전류)분포를 갖는 누설파 구조의 슬릿영역의 등가 자계전류와 복사특성에 관한 결과들을 제시하고 상호 비교하여 보았다.

• 대한전자공학회논문지
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• 제14권3호
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• pp.6-11
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• 1977

GaAs Schottky Barrier Gate 전계효과트랜지스터의 잡음동작을 잡음등가회로를 사용하여 연구하였으며, 부가구인 잡음근원은 pinch-off영역에서 GaAs FET bias에 의하여 구현되었다. 이것이 바로 intervalley 산란잡음과 hot electron에 의한 잡음이었다. 본 논문의 잡음등가회로에서는 carrier의 포화속도와 기생저항의 영향을 고려한 parameter를 정하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 추계학술대회 논문집 학회본부
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• pp.32-35
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• 1996

This paper analyzes characteristics of PMLSM using 3 dimensional equivalent magnetic circuit network method (3-D EMC). PMLSM of which the effective electric-airgap is not only very large, but also the width is finite width lateral edges has much leakage flux. Therefore, 2-D analysis method cannot consider it so carefully that 3-D analysis method must required. 3-D EMC which will be used for analysis of PMLSM performs modeling of it including solt and teeth structure, uses the magnetic motive force of stator winding and permanent magnet as source. and calculates magnetic flux density and force considering nonlinear characteristics of materials. we verified analysis validity by comparing simulation results with expermental results.

• 전기학회논문지
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• 제63권1호
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• pp.42-47
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• 2014

The use of BLDC motor in Vehicle and industrial field, it is operated by continuous and intermittent driving. When the intermittent driving is occurred by the rise and fall of temperature repeatedly, it was represented by different characteristics in case of continuous driving. So, it is very important that heat source estimation according to the duty ratio. In this paper, temperature characteristics according to the operating method of BLDCM was calculated by using the thermal equivalent circuit, and the validity of the study was demonstrated as compared to the calculated and experimental results.

• 한국전기전자재료학회논문지
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• 제29권2호
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• pp.69-74
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• 2016

In this study, we proposed an a-IGZO (amorphous In-Ga-Zn-O) TFT (thin-film transistor) with off-planed source/drain structure. Furthermore, two different electrode materials (ITO and Ti) were applied to the source and drain contacts for performance improvement of a-IGZO TFTs. When the ITO with a large work-function and the Ti with a small work-function are applied to drain electrode and source contact, respectively, the electrical performances of a-IGZO TFTs were improved; an increased driving current, a decreased leakage current, a high on-off current ratio, and a reduced subthreshold swing. As a result of gate bias stress test at various temperatures, the off-planed S/D a-IGZO TFTs showed a degradation mechanism due to electron trapping and both devices with ITO-drain or Ti-drain electrode revealed an equivalent instability.

• 전력전자학회논문지
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• 제10권1호
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• pp.70-77
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• 2005

압전소자를 이용한 마이크로발전기를 모델링한 저전압 AC 전류원으로부터 밧데리 충전을 위한 에너지 변환회로를 제안하고, 동작모드를 해석한다. 전체 시스템의 소형화 및 고효율화를 추구하기 위해서, MOSFET 풀브리지 정류기와 부스트 컨버터의 토폴로지를 채택하였다. 제안된 컨버터 시스템의 동작원리 및 동작모드를 스위칭 소자의 기생캐패시턴스를 고려하여 해석하고, 시뮬레이션을 통해 해석결과를 검증하였다.

• Nuclear Engineering and Technology
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• 제31권5호
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• pp.512-521
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• 1999

A feasibility study was performed to design an epithermal neutron beam for BNCT using the neutron of 2.45 MeV on the average produced from $^2H(d,n)^3$He reaction induced by plasma focus in the z-pinch instead of the conventional accelerator-based $^3H(d, n)^4$He neutron generator. Flux and spectrum were analyzed to use these neutrons as the neutron source for BNCT. Neutronic characteristics of several candidate materials in this neutron source were investigated Using MCNP Code, and $^7LiF$ ; 40%Al + 60%$AIF_3$, and Pb Were determined as moderator, filter, and reflector in an epithermal neutron beam design for BNCT, respectively. The skin-skull-brain ellipsoidal phantom, which consists of homogeneous regions of skin-, bone-, or brain-equivalent material, was used in order to assess the dosimetric effect in brain. An epithermal neutron beam design for BNCT was proposed by the repeated work with MCNP runs, and the dosimetric properties (AD, AR, ADDR, and Dose Components) calculated within the phantom showed that the neutron beam designed in this work is effective in tumor therapy. If the neutron source flux is high enough using the z-pinch plasma, BNCT using the neutron source produced from $^2H(d,n)^3$He reaction will be very feasible.

• 센서학회지
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• 제27권5호
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• pp.335-339
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• 2018

The optical characteristics of a terahertz (THz) antenna-coupled bolometer (ACB) detector were evaluated using a pulsed quantum cascade laser (QCL) and radiation blackbody sources. We investigated a method for measuring the responsivity and noise-equivalent power (NEP) of the THz detector using two different types of light sources. When using a QCL source with a frequency of 3 THz, the average responsivity of 24 devices was $1.44{\times}10^3V/W$ and the average NEP of those devices was $3.33{\times}10^{-9}W/{\surd}Hz$. The average responsivity and NEP as measured by blackbody source were $1.79{\times}10^5V/W$ and $6.51{\times}10^{-11}W/{\surd}Hz$, respectively, with the measured values varying depending on the light source. This was because the output power of each light source was different, with the laser source being driven by a pulse type wave and the blackbody source being driven by a continuous wave. The power input to the THz sensor was also different. Futhermore, the responsivity and NEP values measured using band pass filter (BPF) were similar to those measured when using only THz windows. It was found that ACB sensor responds normally in the THz region to both the laser and the blackbody source, and the method was confirmed to effectively evaluate the characteristics of the THz sensor.

• 한국음향학회지
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• 제22권2호
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• pp.104-112
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• 2003

유체기계 덕트 내 음원은 흔히 선형 시불변 모델을 이용하여 음원 임피던스와 강도로 특성화되어진다. 그러나 내연기관 및 압축기 음원에 대한 여러 측정에서 물리적으로 타당하지 않은 부의 저항이 보고된 바 있다. 본 논문에서는 유체기계의 시변성이 음원특성에 미치는 영향에 대하여 해석적으로 연구하였다. 이를 위하여 왕복동 피스톤 및 배기계로 구성된 간단한 유체기계를 전형적인 주기적으로 시변하는 계로서 다루었으며 등가음향 회로를 해석하였다. 해석 해를 이용한 모사측정에서는 실제 음원의 시변성이 부의 저항에 대한 주요한 원인임을 볼 수 있다. 비교적 작은 시변항의 크기를 가지는 경우에 피스톤이 정적 계의 고유진동수의 두 배 또는 그 정수로 나뉜 주파수로 작동한다면 음원이 큰 음향 파워를 방사하게 됨을 알 수 있다.