• 한국전자파학회논문지
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• 제16권1호
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• pp.56-65
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• 2005

이 논문은 군 쉘터(shelter)내부의 전자기기용 전원부에 사용되는 고성능 전원용 광대역 EMI 필터를 제안하였다. 주파수 10 kHz~l GHz의 광대역에서 감쇠량 100 dB를 구현할 수 있는 최적의 EMI 필터를 구현하기 위해 먼저 시뮬레이션을 통해 각 소자의 용량에 대한 특성을 분석하였으며, 이를 기초로 실제 제작을 통해 실험적으로 노이즈 제거 성능을 증명하였다. 이 결과는 군용 쉘터뿐만 아니라 다른 첨단 무기들에 대한 전자파 대응 방호기술의 개발에 도움을 줄 것이다.

• 한국전자파학회논문지
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• 제16권3호
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• pp.270-276
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• 2005

본 논문에서는 S-DMB(Satellite Digital Multimedia Broadcasting) 수신기 에 인접 한 UWB 기기로부터의 방사전력이 S-DMB 수신기에 미치는 간섭 영향을 분석한다. 우선 S-DMB 수신기의 사양에 맞추어 C/N$_{o}$을 유도한 후 ITU-R에서 권고한 S-DMB 수신부의 C/(N$_{o}$+I)와 I/N$_{o}$의 관점에서 UWB 간섭을 이론적으로 분석한다. 분석 결과에 입각해서 수신기가 간섭을 받지 않는 이격거리를 유도하고 또한 최소 이격거리(1 m로 가정)에서 간섭을 받지 않을 수 있는 UWB 방사 전력 한도를 제시하고 FCC 권고값과 비교한다

• 한국전자파학회논문지
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• 제8권1호
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• pp.61-72
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• 1997

대역확산 코드분할 다원 접속(CDMA) 기술을 이용하는 팡대역 코드분할 다원 접속 개인 휴대 통신 ((Wideband CDMA PCS) 기지국용 RF 송수선기를 고찰하였다. 5 MHz의 RF 채널 대역폭을 이용하여 넓은 동작 범위와 고감도에 요구되는 RF 수신기 빛 우수한 스퓨리어스 방사 억제 특성을 가지는 송신기의 설계 및 구 현에 대하여 기술하였다. 상용화된 부품이나 주문 제작된 소자의 규격을 토대로 상용 RF 시율레이션 소프트웨어 를 이용하여 송수신기 구성시 고려되어야 할 사항 및 예상 성능에 대하여 알아보았고, 이에 따라 송수신기를 설계 제작하고 설험하여 성능 규격을 만족하는 좋은 결과를 얻었다

• 전기학회논문지
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• 제65권5호
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• pp.711-717
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• 2016

Recently, fuel cell generation system with high energy efficiency and low CO2 emission is energetically interconnected with distribution power system. Especially, MCFC(molten carbonate fuel cell) operating at high temperature conditions is commercialized and installed as a form of large scale power generation system. However, it is reported that power system disturbances such as harmonic distortion, surge phenomenon, unbalance current, EMI(Electromagnetic Interference), EMC (Electromagnetic Compatibility) and so on, have caused several problems including malfunction of protection device and damage of control devices in the large scale FCGS(Fuel Cell Generation System). Under these circumstances, this paper proposes countermeasure algorithms to prevent power system disturbances based on the modelling of PSCAD/EMTDC and P-SIM software. From the simulation results, it is confirmed that proposed algorithms are useful method for the stable operation of a large scale FCGS.

• 전기학회논문지
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• 제60권1호
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• pp.131-137
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• 2011

This paper analyzes EM(Electromagnetic) characteristic in the high voltage connector for the hybrid electric vehicle. The connector bridges the electrical components and helps transferring electrical power and signal through it. The necessity of the high voltage and current connector development is emphasized because the hybrid electric vehicle recently uses the high voltage and current more than 500V and 80A. So far there has not been international EMC (Electromagnetic Compatibility) standards to limit the RE(Radiation Emission) from the connector for the hybrid electric vehicle. In this paper we analyzed EM characteristic of the 288V, 65A connector to check if the RE from the high voltage connector could be within the RE limit standard of vehicle. Three-dimensional modeling and simulation was conducted by using MWS(Microwave Studio) of the CST corporation, and the result was compared with the measured RE data, which showed good coincidence each other.

• 방사선산업학회지
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• 제9권1호
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• pp.15-20
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• 2015

Carbon fiber has received much attention owing to its properties, including a large surface-to-volume ratio, chemical and thermal stability, high thermal and electrical conductivity, and high mechanical strengths. In particular, magnetic nanopowder dispersed carbon fiber has been attractive in technological applications such as the electrochemical capacitor and electromagnetic wave shielding. In this study, the nickel-oxide-nanoparticle dispersed polyacrylonitrile (PAN) fibers were prepared through an electrospinning method. Electron beam irradiation was carried out with a 2.5 MeV beam energy to stabilize the materials. The samples were then heat-treated for stabilization and carbonization. The nanofiber surface was analyzed using a field emission scanning electron microscope (FE-SEM). The crystal structures of the carbon matrix and nickel nanopowders were analysed using X-ray diffraction (XRD). In addition, the magnetic and electrical properties were analyzed using a vibrating sample magnetometer (VSM) and 4 point probe. As the irradiation dose increases, the density of the carbon fiber was increased. In addition, the electrical properties of the carbon fiber improved through electron beam irradiation. This is because the amorphous region of the carbon fiber decreases. This electron beam effect of PAN fibers containing nickel nanoparticles confirmed their potential as a high performance carbon material for various applications.

• Journal of Astronomy and Space Sciences
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• 제36권2호
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• pp.45-60
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• 2019

The Earth's outer radiation belt has long received considerable attention mainly because the MeV electron flux in the belt varies often dramatically and at various time scales. It is now widely accepted that the wave-particle interaction is one of the major mechanisms responsible for such flux variations. The wave-particle interaction can accelerate electrons to MeV energies, explaining the observed flux increase events, and can also scatter the electrons' motion into the loss cone, resulting in atmospheric precipitation and thus contributing to flux dropouts. In this paper, we provide a review of the current state of research on relativistic electron scattering and precipitation due to the interaction with electromagnetic ion cyclotron (EMIC) waves in the inner magnetosphere. The review is intended to cover progress made over the last ~15 years in the theory and simulations of various issues, including quasilinear resonance diffusion, nonlinear interactions, nonresonant interactions, effects of finite normal angle on pitch angle scattering, effects due to rising tone emission, and ways to scatter near-equatorial pitch angle electrons. The review concludes with suggestions of a few promising topics for future research.

• Composites Research
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• 제27권4호
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• pp.152-157
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• 2014

Non-destructive testing methods of composite materials are very important for improving material reliability and safety. AE measurement is based on the detection of microscopic surface movements from stress waves in a material during the fracture process. The examination of AE is a useful tool for the sensitive detection and location of active damage in polymer and composite materials. FBG (Fiber Bragg Grating) sensors have attracted much interest owing to the important advantages of optical fiber sensing. Compared to conventional electronic sensors, fiber-optical sensors are known for their high resolution and high accuracy. Furthermore, they offer important advantages such as immunity to electromagnetic interference, and electrically passive operation. In this paper, the crack detection capability of AE (Acoustic Emission) measurement was compared with that of an FBG sensor under tensile testing and buckling test of composite materials. The AE signals of the PVDF sensor were measured and an AE signal analyzer, which had a low pass filter and a resonance filter, was designed and fabricated. Also, the wavelength variation of the FBG sensor was measured and its strain was calculated. Calculated strains were compared with those determined by finite element analysis.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
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• pp.1123-1126
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• 2003

In this paper, the emission properties of electrodeless fluorescent lamp were discussed using the inductively coupled plasma. To transmit the electromagnetic energy into the chamber, a RF power of 13.56MHz was applied to the antenna and considering the Ar gas pressure and the RF electric power change, the emission spectrum, Ar- I line, luminance were investigated. At this time the input parameter for ICP RF plama, Ar gas pressure and RF power were applied in the range of $10{\sim}60m$ Torr, $10{\sim}300W$ respectively.

• 한국정밀공학회지
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• 제29권11호
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• pp.1183-1189
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• 2012

Organic light-emitting diodes (OLEDs) using microcavity effect have attracted great attention because they can reduce the width of emission spectra from organic materials, and enhance brightness from the same material. We demonstrate the simulation results of the radiation properties from top-emitting organic light-emitting diodes (TE-OLEDs) with microcavity structures based on the general electromagnetic theory. Organic materials such as N,N'-di (naphthalene-1-yl)-N,N'-diphenylbenzidine (NPB) as a hole transport layer and tris (8-hydroxyquinoline) ($Alq_3$) as emitting and electron transporting layer are used to form the OLEDs. The organic materials were sandwiched between anode such as Ni or Au and cathode such as Al, Ag, or Al:Ag. The devices were characterized with electroluminescence phenomenon. We confirmed that the simulation results are consistent with experimental results.