• Title/Summary/Keyword: Dispersive material

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Effective Medium Approach of Left Handed Material using a Dispersive FDTD Method (분산 FDTD 법을 이용한 LHM의 유효 매질 접근법)

  • Lee Jung-Yub;Lee Jeong-Hae;Kim Hyeong-Seok;Jung Hyun-Kyo
    • 한국정보통신설비학회:학술대회논문집
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    • 2004.08a
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    • pp.15-18
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    • 2004
  • LHM (Left Handed Material)은 특정 주파수 범위에서 음의 유전율과 투자율을 가지는 물질이다. 이 물질의 유효 유전율과 투자율은 분산 특성을 가지며 로렌츠 (Lorentz) 물질과 비슷한 형태를 가진다. 본 논문에서는 FDTD (Finite Difference Time Domain) 법을 바탕으로 한 PLRC (Piecewise Linear Recursive Convolution) 법을 이용하여 LHM 내의 유효 전파특성을 모의한다. 모의실험 결과는 음의 유전율과 투자율을 가지는 주파수 범위를 보여준다.

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ZnO Crystals with Belt and Comb Shapes Synthesized by Oxidation of ZnS in Air Atmosphere (공기 중 대기압 분위기에서 ZnS의 산화에 의해 생성된 벨트형상과 빗 형상의 ZnO 결정)

  • Lee, Geun-Hyoung
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.24 no.11
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    • pp.920-924
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    • 2011
  • ZnO crystals with belt and comb shapes were synthesized without any catalysts through a simple thermal oxidation of ZnS powder in alumina crucible under air atmosphere. X-ray diffraction (XRD) pattern revealed that the ZnO crystals had wurtzite structure of hexagonal phase. Energy dispersive x-ray (EDX) spectra showed that the ZnO was of high purity. In the cathodoluminescece spectra obtained for the ZnO crystals with belt and comb shapes, a strong ultraviolet emission centered at 380nm was observed, which indicates the ZnO crystal has high crystalline quality.

Synthesis and Characterization of Te-rich $Sb_xTe_{1-x}$ Nanowires and Nanotubes (Te이 과량 포함된 $Sb_xTe_{1-x}$ 나노와이어 및 나노튜브의 합성 및 분석)

  • Lee, Joon-Suk;No, Kwang-Soo;Jung, Soon-Won;Yoon, Sung-Min;Yu, Byoung-Gon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.11a
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    • pp.423-423
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    • 2008
  • One dimensional (1D) nanostructures, including nanowires, nanorods, nanobelts, and nanotubes, have been the focus of current research on nanotechnology because of their fundamental significance in chemistry, physics, materials science and engineering, and potential applications in nanoelectronics. We have synthesized Te-rich $Sb_xTe_{1-x}$ nanowires and nanotubes via thermal evaporation method under vapor-solid mechanism. The physical morphology and chemical composition of the fabricated nanowires and nanotubes were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDX).

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Exciting High Frequency Oscillations in a Coaxial Transmission Line with a Magnetized Ferrite

  • Ahn, J.-W.;Karelin, S.Y.;Kwon, H.-O.;Magda, I.I.;Sinitsin, V.G.
    • Journal of Magnetics
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    • v.20 no.4
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    • pp.460-465
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    • 2015
  • The paper presents methodologies and results concerning one- and two-dimensional numerical modeling of radio frequency oscillations in a coaxial transmission line fed with a short pulse of electric current. The line is partially filled with a ferrite material, magnetized longitudinally close to saturation. The 2D model has permitted analyzing, for the first time in the art, the spatial structure and dynamics of the wave field within the radially non-uniform cross-section planes of the non-linear and dispersive guiding structure. This opens ways for optimizing size parameters of the line and the extent to which it is filled with the ferromagnetic material, thus increasing the line's electric strength and intensity of the r.f. oscillations.

The characteristics of joints with In-Ag alloy (Indium-silver alloy를 이용한 접합의 특성)

  • Kim, Jae-Wook;Kim, Je-Yoon;Kim, Sang-Sig;Sung, Man-Young
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.07a
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    • pp.256-258
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    • 2003
  • Two Si wafers are bonded with indium-silver alloy using diffusion bonding method. When silver and indium thin films are contacted, they diffuse into each other and form inter-metallic compounds like $AgIn_2$, $Ag_2In$, $Ag_3In$ etc. These compounds are determined by ratio of two metals. From phase diagram of Ag-In alloy, we can get the ratio of $Ag_2In$, that has high melting point about 700$^{\circ}C$, approximately 2:1. This ratio was made by controlling of film thickness. And bonding was executed by annealing and adding pressures at a time. The joint of these wafers had been observed by SEM. And we had also seen the EDS (Energy Dispersive Spectroscopy) data to analysis the component of samples.

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Gate Dielectrics and Oxynitridation of Silicon using $N_2O$ Plasma Oxidation ($N_2O$ Plasma Oxidation을 이용한 Silicon의 Oxynitridation과 Gate Dielectrics)

  • Jung, Sung-Wook;Gowtham, M.;Igor, Parm.;Lee, Jun-Sin
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.11a
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    • pp.93-94
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    • 2005
  • 본 연구에서는 저온 공정에서 제작되는 소자에의 응용을 위하여 Inductively Coupled Plasma Chemical Vapor Deposition(ICP-CVD) 내에서 $N_2O$ 기체를 활용한 plasma oxidation을 통한 silicon 표면의 oxynitridation과 이로부터 tunnel gate dielectirics로 사용될 SiON 층을 형성하였으며, 형성된 SiOxNy 층의 전기적 특성을 측정하여 tunnel gate dielectrics로서 효과적인 기능을 수행함을 확인하였다. 형성된 박막의 성분 분석을 위하여 energy dispersive spectroscopy(EDS)를 이용하여 SiOxNy 층의 생성을 확인하였으며, 전기적인 특성을 통하여 tunnel gate dielectrics의 기능을 수행함을 알 수 있었다. 형성된 SiOxNy 층은 초박막 형태임에도 절연막으로서의 기능을 나타내었다.

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VHCF Characteristics of SCMH2 Steel Depending on the Surface Treatment Conditions (SCMH2 고속회전축재의 표면처리조건에 따른 VHCF 피로특성에 관한 연구)

  • Suh, C.M.;Suh, C.H.;Suh, M.S.
    • Journal of Welding and Joining
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    • v.31 no.4
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    • pp.47-53
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    • 2013
  • SCMH2 steel is widely used in the industrial members of car and tractor. This study focused on material properties and evaluation technology of the SCMH2 steel regarding the surface treatment followed by carburizing and nitriding, by means of impact test, hardness test. and fatigue test including HCF (high cycle fatigue) and VHCF (very high cycle fatigue). Drop weight impact tester (Instron, 9250 Hv) and Cantilever type rotating-bending fatigue tester (YRB200, 3150 rpm) were used to characterize the SCMH2 standard specimen before and after carburizing/nitriding. In order to understand those effects on fatigue characteristics and material properties, the fractured surfaces were carefully observed and analyzed by SEM (scanning electron microscope) and EDS (energy-dispersive X-ray spectroscopy).

I-V Characteristics of $KNO_3$ Electrolyte for ECMP Application (ECMP 적용을 위한 $KNO_3$ 전해액의 I-V 특성 고찰)

  • Han, Sang-Jun;Lee, Young-Kyun;Park, Sung-Woo;Lee, Woo-Sun;Seo, Yong-Jin
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.06a
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    • pp.115-115
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    • 2008
  • 본 논문에서는 최적화된 ECMP 공정을 위하여 I-V 특성 곡선과 CV법을 이용하여 패시베이션 막의 active, passive, transient, trans-passive 영역의 전기화학적 특성을 알아보았으며, Cu막의 표면 형상을 Scanning Electron Microscopy (SEM) 측정과 금속 화학적 조성을 Energy Dispersive Spectroscopy (EDS) 분석을 통해 분석하였다.

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A Study on the electrochemical mechanism of $NaNO_3$ electrolyte ($NaNO_3$ 전해액의 전기화학적 메커니즘 연구)

  • Lee, Young-Kyun;Han, Sang-Jun;Park, Sung-Woo;Lee, Woo-Sun;Seo, Yong-Jin
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.06a
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    • pp.116-116
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    • 2008
  • Cu CMP 공정시 높은 압력으로 인하여 low-k 유전체막에 손실을 주며, 디싱과 에로젼 같은 문제점을 해결하기 위하여 기존의 CMP에 전기화학을 결합시킴으로서 낮은 하력에서의 Cu 평탄화를 달성 할 수 있는 ECMP(Electrochemical Mechanical Polishing)기술이 필요하게 되었다. 본 논문에서는 $NaNO_3$ 전해액이 Cu 표면에 미치는 영향을 SEM (Scanning electron microscopy), EDS (Energy Dispersive Spectroscopy), XRD(X-ray Diffraction)를 통하여 전기화학적 특성을 비교 분석하였다.

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A Study on the Deposition of Permalloy Nanostructured Thin Film Utilizing Supersonic Deposition of Nanoparticles Formed by Laser Ablation of Microparticles (마이크로입자의 레이저 Ablation으로 형성된 나노입자의 수펴소닉 적층법을 이용한 퍼멀로이 나노구조박막 적층에 관한 연구)

  • Yun, Eui-Jung;Jung, Myunghee
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.18 no.5
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    • pp.478-483
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    • 2005
  • In this paper, we synthesized 10 to 20 nm diameter NiFe nanoparticles and nanoparticle films utilizing supersonic jet deposition of nanoparticle aerosols generated by laser ablation of $30\;to\;45{\mu}m$ diameter permalloy $(Ni_{81}Fe_{19} \;at\;{\%})$ microparticles. The component and composition of the nanoparticles were characterized by an energy dispersive X-ray spectroscopy. The morphology of the nanoparticles and nanoparticle films was analyzed by a high-resolution transmission electron microscopy and a scanning electron microscopy, respectively. The experimental results showed that the nanoparticles and nanoparticle films have remarkable properties with an excellent preservation of the composition of feedstock permalloy microparticles. The purpose of the present work is to present details on the composition and nanostructural characterizations for NiFe nanoparticles and nanoparticle films prepared by laser ablation of microparticles (LAM).