• 한국전자파학회논문지
• /
• 제25권11호
• /
• pp.1183-1189
• /
• 2014

본 논문에서는 손실판(resistive sheet) 방식을 사용하여 풀잎이나 나뭇잎의 후방 산란 레이더 단면적(RCS: Radar Cross Section)을 계산하고, 이 모델의 정확성을 검증하여, 손실판 모델을 적용하여 계산 가능한 잎의 두께를 제시한다. 이를 위해 잎을 손실 있는 유전체 판으로 가정하고, 이 유전체 판을 resistive sheet(손실판)으로 대체한 후에 판의 두께, 유전율, 주파수에 따른 resistivity를 계산한 후에, PO(Physical Optics) 방식을 이용하여 다양한 크기와 두께 조건에서 RCS를 계산하였고, 이 계산 결과를 상용 시뮬레이터를 사용한 FEM(Finite Element Method) 방식의 수치해석 계산 결과와 비교하였다. 이 비교 결과에 의하면 유전체 판의 두께가 커질수록 오차가 증가하였으며, 예를 들어, 주파수 9.6 GHz에서 유전율이 21.4+9.7i이고, 잎 두께가 1.2 mm일 때 0.1 dB의 오차가 발생하였고, 3 mm일 때 3.74 dB의 오차가 발생하였다. 또한, 유전율이 높아질수록 이 모델 사용 가능한 최대 두께가 증가하는 경향을 보였다. 이 연구는 원격탐사 연구에서 수많은 잎이 분포되어 있을 때에 그 잎들의 산란 특성을 산란모델을 이용하여 계산하는 데에 유용하게 사용될 것이다.

• 한국구조물진단유지관리공학회 논문집
• /
• 제26권5호
• /
• pp.151-160
• /
• 2022

최근 폭발사고의 빈도수가 증가함에 따라 주요 구조부재의 손상을 저감시킬 수 있는 방호 구조물 설계에 대한 관심이 높아지고 있다. 그러나, 방호 구조물의 방호성능에 대한 국내 연구는 아직 미진한 실정이며, 아직 설계 가이드라인도 충분히 갖추어지지 못한 실정이다. 따라서, 본 연구에서는 FRP 시트 보강유무를 변수로 하여 RC 방호벽에 대한 해석적 연구를 수행하였다. 해석은 LS-DYNA 프로그램을 활용하여 수행되었으며, 해석을 통해 RC 방호벽과 FRP 시트로 보강된 RC 방호벽의 변위-시간이력곡선, 압력-충격량 도표, 취약도 곡선을 도출하였다. FRP 시트 보강방법은 RC 방호벽의 방호성능을 향상시키는데 매우 효율적인 것으로 나타났다. 또한, 폭발하중의 크기가 클수록 RC 방호벽에 대한 FRP 시트의 보강효과는 높아지는 것으로 나타났다.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 2007년도 춘계학술대회 논문집
• /
• pp.214-217
• /
• 2007

This paper presents a reduction method of penetrated electromagnetic fields through a narrow slot with resistive sheet in a planar conducting screen of infinite extent. When a plane wave is excited to the narrow slot, the aperture electric field is controlled by the parallel plates connected on the slot. The magnitude of penetrated electromagnetic fields through the narrow slot is controlled by the electric field distribution on the slot. The results show that the magnitude of the penetrated electromagnetic field can be effectively reduced by installing the resistive plates on the slot.

• 반도체디스플레이기술학회지
• /
• 제20권1호
• /
• pp.54-58
• /
• 2021

The RGO with controllable oxygen functional groups is a novel material as the active layer of resistive switching memory through a reduction process. We designed a nanoscale conductive channel induced by local oxygen ion diffusion in an Au / RGO+GQD / Al resistive switching memory structure. A strong electric field was locally generated around the Al metal channel generated in BIL, and the local formation of a direct conductive low-dimensional channel in the complex RGO graphene quantum dot region was confirmed. The resistive memory design of the complex RGO graphene quantum dot structure can be applied as an effective structure for charge transport, and it has been shown that the resistive switching mechanism based on the movement of oxygen and metal ions is a fundamental alternative to understanding and application of next-generation intelligent semiconductor systems.

• Journal of electromagnetic engineering and science
• /
• 제16권2호
• /
• pp.106-111
• /
• 2016

A resistive and capacitive (RC) microwave absorber with a layer thickness less than a quarter of a wavelength is investigated based on closed-form design equations, which are derived from the equivalent circuit of the RC absorber. The RC absorber is shown to have a theoretical 90% absorption bandwidth of 93% when the electrical layer thickness is $57^{\circ}$ (about ${\lambda}_0/6$). The trade-offs between the layer thickness and the absorption bandwidth are also elucidated. The presented formulation is validated by a design example at 3 GHz. The RC absorber is realized using a silver nanowire resistive rectangular structure with surrounding gaps. The measured 90% absorption bandwidth with a layer thickness of ${\lambda}_0/8$ is 76% from 2.3 GHz to 5.1 GHz in accordance with the theory and EM simulations. The presented design methodology is scalable to other frequencies.

• E2M - 전기 전자와 첨단 소재
• /
• 제8권2호
• /
• pp.196-203
• /
• 1995

We presented Tungsten and Tungsten Nitride thin films deposited by RF and DC sputtering. It deposited at various conditions that determining the resistivity and sheet resistivity by stabilizing the basic theory. We investigated properties of the resistivity and sheet resistivity of these films under various conditions, temperature of substrate, flow rate of the argon gas and content of nitrogen from nitrogen-argon mixtures. As the temperature of substrate increased and the flow rate of the argon gas decreased, the resistivities of these films reduced by structural transformation. We found that these resistivities were depend on the temperature of substrate, flow rate and electric power. Very highly resistive tungsten films obtained at 10W RF power. On the contrary, we found that films deposited by DC sputtering, from which very lowly resistive tungsten films were obtained. Tungsten nitride thin films deposited by reactive DC sputtering and the resistivities of these films increased as the content of nitrogen gas increased from nitrogen-argon mixture. And also we found the results show very good agreement, compared with experimental data.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
• /
• pp.1535-1537
• /
• 2009

High performance resistive type touch panel was fabricated on flexible polyethylene terephthalate (PET) substrates coated with Al- and Ga-codoped ZnO (AGZO) films. The AGZO films were deposited by roll-to-roll direct current magnetron sputter at room temperature. The AGZO thin films on PET substrates showed high transparency (> 85 % at 550 nm) and low sheet resistance (450 ${\Omega}$/sq.). These values were similar to those of commercial ITO films used for resistive type touch panel.

• 소성∙가공
• /
• 제16권4호
• /
• pp.313-316
• /
• 2007

The purpose of this paper is the development of measurement algorithm for green-sheet based on the digital image processing technique. The Low Temperature Co-fired Ceramic(LTCC) technology can be employed to produce multilayer circuits with the help of single tapes, which are used to apply conductive, dielectric and/or resistive pastes on. These single green-sheets must be laminated together and fired at the same time. Main function of the green-sheet film measurement algorithm is to measure the position and size of the punching hole in each single layer. The line scan camera coupled with motorized X-Y stage is used. In order to measure the entire film area using several scanning steps, an overlapping method is used.

• 한국전자파학회논문지
• /
• 제26권3호
• /
• pp.311-316
• /
• 2015

본 논문에서는 저항성 sheet를 이용한 광대역 박형 흡수체 설계법을 제안한다. 제안된 흡수체의 등가회로는 직렬 RLC 공진회로와 종단이 단락된 전송선으로 이루어진다. 이 등가회로를 바탕으로 임의의 설계주파수에서 흡수체가 ${\lambda}/4$보다 얇은 두께를 가지면서도, 광대역 흡수율 특성을 가지는 세가지 조건을 정리하였다. 수치해석을 통해 이를 동시에 만족하는 R, L, C 소자 값을 구했다. 구한 등가 R, L, C값은 특정한 chip 저항이나 표면저항을 가지는 십자 모양의 구조로써 구현이 가능하다. 이러한 설계법을 설계 중심주파수 3 GHz에서 적용해서 두께가 18.75 mm(전기적 길이 $67.5^{\circ}$)이고, 90 % 흡수율 기준으로 116 % 대역폭을 갖는 광대역 흡수체를 설계하였다.

• 설비공학논문집
• /
• 제28권9호
• /
• pp.350-354
• /
• 2016

Although fibrous insulations are generally used with resistive insulation type, metallic insulation is proper matter to satisfy low head-loss and equipment life when considering the specific condition, especially for Nuclear power plant. Common insulation is resistance insulation with a low thermal conductivity. but RMI is made of sheet plate with low emissivity and closed air space. Thermal radiation is blocked by stainless steel with low emissivity. Thermal conductivity and thermal convection are blocked by closed air space. This study shows the changes and effects of the heat loss according to shape and method of stacking sheet plates inserted into the insulation and analyzed the most optimized way for thermal insulation performance. The result shows that using sheet plate structure through raised and protruding shape processing was the appropriate model to optimize thermal performance. Additionally, insulating performance of RMI improved by placing the sheet plate in a high temperature region intensively.