• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
• /
• pp.76.1-76.1
• /
• 2015

Optical resonances of metallic or dielectric nanoantennas enable to effectively convert free-propagating electromagnetic waves to localized electromagnetic fields and vice versa. Plasmonic resonances of metal nanoantennas extremely modify the local density of optical states beyond the optical diffraction limit and thus facilitate highly-efficient light-emitting, nonlinear signal conversion, photovoltaics, and optical trapping. The leaky-mode resonances, or termed Mie resonances, allow dielectric nanoantennas to have a compact size even less than the wavelength scale. The dielectric nanoantennas exhibiting low optical losses and supporting both electric and magnetic resonances provide an alternative to their metallic counterparts. To extend the utility of metal and dielectric nanoantennas in further applications, e.g. metasurfaces and metamaterials, it is required to understand and engineer their scattering characteristics. At first, we characterize resonant plasmonic antenna radiations of a single-crystalline Ag nanowire over a wide spectral range from visible to near infrared regions. Dark-field optical microscope and direct far-field scanning measurements successfully identify the FP resonances and mode matching conditions of the antenna radiation, and reveal the mutual relation between the SPP dispersion and the far-field antenna radiation. Secondly, we perform a systematical study on resonant scattering properties of high-refractive-index dielectric nanoantennas. In this research, we examined Si nanoblock and electron-beam induced deposition (EBID) carbonaceous nanorod structures. Scattering spectra of the transverse-electric (TE) and transverse-magnetic (TM) leaky-mode resonances are measured by dark-field microscope spectroscopy. The leaky-mode resonances result a large scattering cross section approaching the theoretical single-channel scattering limit, and their wide tuning ranges enable vivid structural color generation over the full visible spectrum range from blue to green, yellow, and red. In particular, the lowest-order TM01 mode overcomes the diffraction limit. The finite-difference time-domain method and modal dispersion model successfully reproduce the experimental results.

• 한국결정성장학회지
• /
• 제12권4호
• /
• pp.210-214
• /
• 2002

$450^{\circ}C$ 이하에서 Cu를 이용한 전계 유도 방향성 결정화 공정을 통해 비정질 실리콘의 결정화 거동을 고찰하였다. 열처리와 동시에 전계를 인가하여 Cu가 증착된 패턴의 외부에서 Cu가 존재하지 않는 비정질 실리콘의 영역으로 측면 결정화를 유도하였다. 특히, Cu가 존재하지 않는 영역의 측면결정화는 (-) 전극 쪽에서 (+) 전극 쪽으로 방향성을 가지고 결정화가 진행되었다. 이러한 현상은 Cu와 Si가 반응 할 때, 주확산 종이 금속(Cu)이기 때문에 가능하다고 판단되었다. 또한, FALC 공정을 이용한 $350^{\circ}C$의 온도에서 결정화된 영역 내에 커다란 dendrites 형태의 가지가 형성되었고 전계 방향에 따른 측면 결정화가 진행되었음을 확인하였다. 결론적으로 $350^{\circ}C$의 매우 낮은 온도에서 30 V/cm의 전계 인가를 통해 12$\mu$m/h의 결정화 속도로 결정화가 가능함을 확인하였다.

• 한국전자파학회논문지
• /
• 제23권3호
• /
• pp.392-401
• /
• 2012

본 논문에서는 다층 지하 구조물로의 고고도 전자기파(high altitude electromagnetic pulse: HEMP)의 커플링 현상을 분석하였다. 이를 위하여, 고고도 전자기파에 대한 모델링을 통하여, 고고도 전자기파의 스펙트럼이 100 MHz 이상의 대역에서 -30 dB 이하로 급격히 감소함을 확인하였다. 또한, 고고도 전자기파의 커플링 영역인 다층 지하 구조물은 지구의 표면과 내부를 구성하는 5층 구조물로 가정하여, 본 구조물을 구성하는 물질의 전파 상수(propagation constant)를 바탕으로 투과 현상을 분석하였다. 그 결과, 50 kV/m의 평면파를 입사시켰을 때, 지상에서 100 m 깊이에 위치한 지하 터널에서 0.1 MHz와 1 MHz의 평면파에 대하여 각각 약 10 kV/m와 5 kV/m의 투과 현상이 발생함을 확인하였다. 투과된 전기장의 효과적인 차폐 효과 확보를 위하여 토양층의 감쇠 상수(attenuation constant)를 이용한 자연 차폐 방법과 금속 격자 구조물의 필터링(filtering) 현상을 이용한 차폐 방법을 통하여 각각 최대 20 dB와 90 dB의 차폐 효과를 얻을 수 있음을 분석하였다.

• 한국가시화정보학회지
• /
• 제9권4호
• /
• pp.54-62
• /
• 2011

KAERI has developed a KALIMER-600 which is a pool-type sodium-cooled fast reactor with a 600MWe electric generation capacity. For a SFR development, one of the main topics is an enhancement of the reactor system safety. Therefore, we have a long-term plan to design the large sodium experimental facility to evaluate the reactor safety and component performance. In order to extrapolate a thermal hydraulic phenomena in a large sodium reactor, the thermal hydraulics phenomena is under investigation in a 1/$10^{th}$ water-simulant facility for the KALIMER-600. In this paper, we shortly described the experimental facility setup and the measurement of the isothermal global flow behavior. For the flow field measurement, the PIV method was used in a transparent Plexiglas reactor vessel model at around $20^{\circ}C$ water condition.

• 전기학회논문지
• /
• 제56권6호
• /
• pp.1031-1034
• /
• 2007

Electric transmission lines pass through a variety of area. Foundation supporting the conductors and tower are selected properly in accordance with external load, for example dead load, wind load, snow load, construction load etc, and topography and geology condition. Typical types of foundation are as follows: pad foundation for small load and hard soil or rock in mountainous area, pile foundation for medium or large load and soft soil in plain field area. This paper introduced cylindrical foundation design & construction for large load and mountainous area. This foundation failure mode against pulling-out show splitting failure by tensile force toward circumferential direction.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1998년도 추계학술대회 논문집
• /
• pp.259-262
• /
• 1998

PbTi $O_3$ family ceramics can be used for the piezoelectric transformer using thickness extensional vibration mode because it is a material with the large anisotropy between electromechanical coupling factors $k_{t}$ and $k_{p}$. However, PbTi $O_3$ family ceramics have a difficult poling condition on account of its large anisotrophy. In this study, the structural and piezoelectric properties of (P $b_{0.76}$ $Ca_{0.24}$)[ $Ti_{0.96}$(M $n_{1}$3/S $b_{2/3}$)$_{0.04}$] $O_3$ system ceramics were investigated as a function of poling voltage in order to find the best poling condition.ion.n.n.ion.n.

• E2M - 전기 전자와 첨단 소재
• /
• 제9권5호
• /
• pp.483-489
• /
• 1996

Power transformer have many unsymmetrical structure and electric field is enhanced in that area. Those unsymmetrical area are not covered oftenly by solid insulating material which is used as a framework specially in gas transformer. By that result there is a possibility to decrease the total insulation class of the transformer. So in this study the electrical characteristic of $FC+SF_6$ mixture gas which is used as coolants for large power gas insulated transformer and its effects on electrical characteristics of structural material are investigated. Also breakdown characteristic with the tension of taping and curvature of the coil are studied which could be used as a design factor of large power transformer.

• Journal of Information Display
• /
• 제1권1호
• /
• pp.20-24
• /
• 2000

We propose on a novel vertical configuration (VC) for a helix-deformed ferroelectric liquid crystal (HDFLC) display that has fast response, high contrast, analog gray scale capability, and wide-viewing characteristics. In contrast to a conventional HDFLC in a planar geometry, smectic layers arrange themselves parallel to the substrates, and thus, extremely uniform alignment of molecules in large area is naturally achieved in our new configuration without additional processes such as the rubbing and/or electric field treatment. Moreover, with a proper design of electrode patterns on the same substrate, multidomain switching is easily realized without employing any complex process of alignment. Our new VC-HDFLC is expected to provide a viable technology to produce a next-generation large area LCD suitable for processing the dynamic image at a video-rate.

• 한국세라믹학회지
• /
• 제34권4호
• /
• pp.337-342
• /
• 1997

This paper describes the design and evaluation of new type piezoelectric bimorph actuator that shows much large mechanical response than those conventional types. The bimorph actuator has modified structure combined with the multilayer actuator(MLA) and the composite multilayer actuator called "Moonie". The design and performancean alysis of bimorph actuator are carried out with Finite Element Method (FEM). Theoretical calculation results show that the generating force and displacement of Moonie-modified bimorph actuator can be improved by about 130% and 150%, respectively. The overshooting and ringing phenomena of the bimorph can be effectively restrained by the pseudo step electric field having a rising time coincied with a period of the fundamental vibration mode of the bimorph.e bimorph.

• Journal of Magnetics
• /
• 제18권4호
• /
• pp.460-465
• /
• 2013

This paper deals with an approach for the initial design of a permanent magnet motor for turrets with large diameters. The proposed design techniques are introduced as three stages. The first is the selection of a pole-slot combination, the second is the selection of the rotor topology, and the last is choosing the outermost dimensions. In every stage, a useful technique is described with considerations for effective fabrication and motor performance, and magnetic field computation is performed using the finite element method.