• 제목/요약/키워드: Hole arrays

검색결과 49건 처리시간 0.031초

저항성 홀배열이 적용된 볼로미터의 적외선 흡수 특성 변화 (Variation in IR Absorption Characteristics of a Bolometer by Resistive Hole-array Patterns)

  • 김태현;오재섭;박종철;김희연;이종권
    • 센서학회지
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    • 제27권5호
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    • pp.306-310
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    • 2018
  • In order to develop a highly sensitive infrared sensor, it is necessary to develop techniques for decreasing the rate of heat absorption and the transition of the absorption wavelength to a longer wavelength, both of which can be induced by decreasing the pixel size of the bolometer. Therefore, in this study, $1{\mu}m$ hole-arrays with a subwavelength smaller than the incident infrared wavelength were formed on the amorphous silicon-based microbolometer pixels in the absorber, which consisted of a TiN absorption layer, an a-Si resistance layer and a SiNx membrane support layer. We demonstrated that it is possible to reduce the thermal time constant by 16% relative to the hole-patternless bolometer, and that it is possible to shift the absorption peak to a shorter wavelength as well as increase absorption in the $4-8{\mu}m$ band to compensate for the infrared long-wavelength transition. These results demonstrate the potential for a new approach to improve the performance of high-resolution microbolometers.

유출홀을 사용한 배열충돌제트의 열/물질전달 특성 (Heat/mass transfer characteristics of arrays of impingement jets using effusion holes)

  • 윤필현;황상동;조형희
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2000년도 춘계학술대회논문집B
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    • pp.125-131
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    • 2000
  • The local heat/mass transfer coefficients for arrays of impinging circular air jets on a plane surface are determined by means of the naphthalene sublimation method. Spent fluid makes a crossflow in the confined space. The crossflow reduces heat/mass transfer at the small gap distance between the jet plate and impingement surface because of reentrainment of the spent fluid. The present study suggests a new exhaust system having effusion holes in the impinging jet plate. The spent air flow out after impingement just through effusion holes located in the upper plate. This system increases heat/mass transfer coefficients and uniformity for small gap distances$(H/d{\leq}2)$

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Surface Plasmon Nanooptics in Plasmonic Band Gap Structures: Interference of Polarization Controlled Surface Waves in the Near Field

  • Kim, D. S.;Yoon, Y. C.;Hohng, S. C.;Malyarchuk, V.;Lienau, Ch.;Park, J. W.;Kim, J. H.;Park, Q. H.
    • Journal of the Optical Society of Korea
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    • 제6권3호
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    • pp.83-86
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    • 2002
  • Nanoscopic emission from periodic nano-hole arrays in thick metal films is studied experimentally. The experiments give direct evidence for SP excitations in such structures. We show that the symmetry of the emission is governed by polarization and its shape is defined the interference of SP waves of different diffraction orders. Near-Held pattern analysis combined with the far-Held reflection and transmission measurements suggests that the SP eigenmodes of these arrays may be understood as those of ionic plasmon molecules.

Analysis of Subwavelength Metal Hole Array Structure for the Enhancement of Quantum Dot Infrared Photodetectors

  • 하재두;황정우;강상우;노삼규;이상준;김종수
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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    • pp.334-334
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    • 2013
  • In the past decade, the infrared detectors based on intersubband transition in quantum dots (QDs) have attracted much attention due to lower dark currents and increased lifetimes, which are in turn due a three-dimensional confinement and a reduction of scattering, respectively. In parallel, focal plane array development for infrared imaging has proceeded from the first to third generations (linear arrays, 2D arrays for staring systems, and large format with enhanced capabilities, respectively). For a step further towards the next generation of FPAs, it is envisioned that a two-dimensional metal hole array (2D-MHA) structures will improve the FPA structure by enhancing the coupling to photodetectors via local field engineering, and will enable wavelength filtering. In regard to the improved performance at certain wavelengths, it is worth pointing out the structural difference between previous 2D-MHA integrated front-illuminated single pixel devices and back-illuminated devices. Apart from the pixel linear dimension, it is a distinct difference that there is a metal cladding (composed of a number of metals for ohmic contact and the read-out integrated circuit hybridization) in the FPA between the heavily doped gallium arsenide used as the contact layer and the ROIC; on the contrary, the front-illuminated single pixel device consists of two heavily doped contact layers separated by the QD-absorber on a semi-infinite GaAs substrate. This paper is focused on analyzing the impact of a two dimensional metal hole array structure integrated to the back-illuminated quantum dots-in-a-well (DWELL) infrared photodetectors. The metal hole array consisting of subwavelength-circular holes penetrating gold layer (2DAu-CHA) provides the enhanced responsivity of DWELL infrared photodetector at certain wavelengths. The performance of 2D-Au-CHA is investigated by calculating the absorption of active layer in the DWELL structure using a finite integration technique. Simulation results show the enhanced electric fields (thereby increasing the absorption in the active layer) resulting from a surface plasmon, a guided mode, and Fabry-Perot resonances. Simulation method accomplished in this paper provides a generalized approach to optimize the design of any type of couplers integrated to infrared photodetectors.

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입사광각의 영향을 최소화한 다결정 주기 구멍 배열 플라즈모닉 컬러 필터의 설계 (Polyperiodic-hole-array Plasmonic Color Filter for Minimizing the Effect of Angle of Incidence)

  • 정기원;도윤선
    • 한국광학회지
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    • 제31권3호
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    • pp.148-154
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    • 2020
  • 본 논문에서는 주기적인 구멍배열(periodic hole array, PHA) 패턴을 가진 나노금속구조 컬러필터의 문제점인 입사광의 각도에 따른 컬러필터 중심파장의 이동을 해결하기 위해 새로운 구멍 패턴인 polyperiodic hole array (PPHA)를 제시한다. 먼저 녹색파장대역 컬러필터를 만들기 위해 구멍의 직경과 주기를 정했으며 propagation length와 skin depth를 고려해 단위셀의 크기, 금속과 유전체의 두께를 설정했다. PPHA 패턴을 만들기 위해 주기적인 구멍배열을 국부적으로 회전시켜 전체적으로는 비주기적이지만 부분적으로 주기적인 패턴을 만들었다. 그 결과 PHA 패턴과 대비하여 PPHA 패턴 나노금속구조 컬러필터는 입사광각이 0°에서 30°까지 증가하였을 때 파장의 이동도가 최대 40% 개선되었다. 본 연구를 통해 나노금속구조 컬러필터의 성능을 향상시킬 수 있으며 디스플레이, 이미지 센서 등 이미징 디바이스 분야에 접목시켜 산업적으로 활용할 수 있을 것으로 예상한다.

가스터어빈형 연속류연소기의 유동에 관한 연구(II) -연소기내의 유동특성- (A Study on Flow Characterstics of Gas Turbine rvpe Combustor (II) - Flow Characteristics in Combustor -)

  • 이근오;지용욱;김형섭
    • 한국안전학회지
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    • 제4권1호
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    • pp.59-70
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    • 1989
  • This paper deals with the experimental study on the flow characteristics in straight flow can type combustor which has been used for high pressure ratio gas turbine combustor. The author has investigated the effects of swirl number and secondary air hole arrays in axial position on the flow characteristics by adopting the tuft method and 5-Hole Pilot Tube. From these experiments, as the swirl number increases, the results obtained is that the area of recirculation zone becomes wide and the position of vortex-core region approaches to the near of fuel nozzle in the model combustor. The most favourable penetration is obtained when secondary air jet is introduced through the air holes distributed in the form of paralled two rows in axial position of model combustor.

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Highly Birefringent Slotted-porous-core Photonic Crystal Fiber with Elliptical-hole Cladding for Terahertz Applications

  • Lee, Yong Soo;Kim, Soeun;Oh, Kyunghwan
    • Current Optics and Photonics
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    • 제6권2호
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    • pp.129-136
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    • 2022
  • We propose a photonic crystal fiber (PCF) with a slotted porous core and elliptical-hole cladding, for high birefringence in the terahertz regime. Asymmetry in the guided mode is obtained mainly by using arrays of elliptical air holes in the TOPAS® polymer cladding. We investigate the tradeoff between several structural parameters and find optimized values that can have a high birefringence while satisfying the single-mode condition. The optical properties in the terahertz regime are thoroughly analyzed in numerical simulations, using a full-vector finite-element method with the perfectly-matched-layer condition. In an optimal design, the proposed photonic crystal fiber shows a high birefringence of 8.80 × 10-2 and an effective material loss of 0.07 cm-1 at a frequency of 1 THz, satisfying the single-mode-guidance condition at the same time. The proposed PCF would be useful for various polarization-management applications in the terahertz range.

가스터어빈형 연속유연소기의 유동에 관한 연구(I) - 연소기의 설계 및 시작 - (A study on Flow Characteristics of Gas Turbine Type Combustor)

  • 이근오;김형섭
    • 한국안전학회지
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    • 제2권3호
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    • pp.37-43
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    • 1987
  • The combustion process in gas turbine combustor mainly influenced by flow pattern in combustor, and especially the flow pattern near the nozzle and the shape of recirculation zone affect strongly on the flame stabilization, temperature distribution and combustion efficiency in combustor. In this paper, the author has designed and manufactured transparent simplified model combustors on the basis of K. Suzuki's combustor design method to investigate the effects of swirl number and secondary air hold arrays in axial position on the flow characteristics by adopting the tuft method and 5 hole pitot tube.

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소수성 텍스쳐 표면에 충돌한 단일 액적의 퍼짐 및 고착 특성 (Spreading and Deposition Characteristics of a Water Droplet Impacting on Hydrophobic Textured Surfaces)

  • 이재봉;문주현;이성혁
    • 한국분무공학회지
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    • 제17권1호
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    • pp.14-19
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    • 2012
  • The present study conducts experimental investigation on spreading and deposition characteristics of a $4.3{\mu}l$ de-ionized (DI) water droplet impacting upon aluminum (Al 6061) flat and textured surfaces. The micro-textured surface consisted the micro-hole arrays (hole diameter: $125{\mu}m$, hole depth: $125{\mu}m$) fabricated by the conventional micro-computer numerical control (${\mu}$-CNC) milling machine process. We examined the surface effect of texture area fraction ${\varphi}_s$ ranging from 0 to 0.57 and impact velocity of droplet ranging from 0.40 m/s to 1.45 m/s on spreading and deposition characteristics from captured images. We used a high-speed camera to capture sequential images for investigate spreading characteristics and the image sensor to capture image of final equilibrium deposition droplet for analyze spreading diameter and contact angle. We found that the deposition droplet on textured surfaces have different wetting states. When the impact velocity is low, the non-wetting state partially exists, whereas over 0.64 m/s of impact velocity, totally wetting state is more prominent due to the increase kinetic energy of impinging droplet.

복합공정을 이용한 스테인레스 박판 마이크로 노즐 어레이 제작 (Fabrication of the Micro Nozzle Arrays on a Stainless Steel Sheet Metal by Using Combined Micro Press and Surface Finishing Process)

  • 박성준;유영석;장현석;김영태;김순영;이상조
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2005년도 춘계학술대회 논문집
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    • pp.1294-1298
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    • 2005
  • In this study, combined micro press and surface finishing process are proposed to fabricate the micro nozzle array on a stainless steel sheet metal. In micro hole punching process the burr occurs inevitably, but the burr must be minimized in order to improve the quality and accuracy of the product. For this reason, subsequent magnetic field-assisted finishing technique is applied to remove the burr which exists around the nozzles for ink-jet printer head and proved to be a feasible for deburring by experiment. The deburring characteristics of sheet metals were investigated changing with polishing time and magnetic abrasive size. After the deburring, the burr size has remarkably reduced and roundness of the hole also has improved.

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