• 제목/요약/키워드: Channel Variation

검색결과 799건 처리시간 0.027초

채널 유동 내 유연한 캡슐의 관성 이동과 움직임 (INERTIAL MIGRATION AND DYNAMICS OF AN ELASTIC CAPSULE IN CHANNEL FLOW)

  • 신수재;성형진
    • 한국전산유체공학회지
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    • 제17권2호
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    • pp.107-112
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    • 2012
  • We explored the dynamic motions and the lateral equilibrium positions of an elastic capsule in channel flow at moderate Reynolds number varying Re, aspect ratio, size ratio, membrane stretching and bending coefficient. The transition of tank-treading/swinging to tumbling motion was observed in the simulations and the transition of dynamic motions for capsules resulted in different trend of the variation in the lateral equilibrium positions. Though other conditions were similar, the capsule with tumbling motion migrated closer to the wall than that with tank-treading motion.

경사각을 갖는 다층채널 흐름의 PIV 계측에 관한 연구 (A Study on PIV Measurement of Multi-Channel Flow with Inclination angle)

  • 조대환
    • 한국마린엔지니어링학회:학술대회논문집
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    • 한국마린엔지니어링학회 2000년도 춘계학술대회 논문집(Proceeding of the KOSME 2000 Spring Annual Meeting)
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    • pp.153-158
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    • 2000
  • Flow visualization and PIV measurements were conducted to investigate the flow characteristics of multi-channel with inclination angle. The water flow seeded with tiny vegetable powder as tracers revealed details of flow field. The PIV measurement to acquire multi-point velocity data simulatneously was carried out at three space of plates for 5, 10, and 15mm with variation of inlet flow rates of $0.25m^3/h$ and <$0.5m^3/h.$ Experiment results show that space of plates acts a significant role in separating process.

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An X-Y Channel Dimming LED Backlight with Temperature Compensation for LCD TVs

  • Oh, Won-Sik;Cho, Dea-Youn;Moon, Gun-Woo
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2008년도 하계학술대회 논문집
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    • pp.335-337
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    • 2008
  • In this paper, an X-Y channel dimming light emitting diode (LED) backlight with temperature compensation for in LCD TVs is proposed. It shows local dimming effects such as reduced power consumption and high dynamic contrast ratio even with much less number of LED drivers than that of the conventional two-dimensional local dimming method. Moreover, the image distortion caused by temperature variation of LED block can be effectively compensated. The validity of the proposed dimming method is verified by simulation and experimental results based on a RGB-LED backlight of a 32-inch LCD TV.

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Flow Characteristics for the Variation of Radius of Curvature in Open Channel Bends

  • Yoon, Sei-Eul;Lee, Jong-Tae
    • Korean Journal of Hydrosciences
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    • 제3권
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    • pp.45-59
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    • 1992
  • The flow characteristics varying with rate of the radius of curvature to width (Rc/B) in open channel bends are investigated with a simplified numerical model. Secondary flow velocity and transverise bed slope are formulated from the equations of momentum and force balance analysis, respectively. The conservation equations of mass and streamwise momentum are simplified by depth integration and its solution could be obtained from the explicit finite difference method. Three sets of computer simulation are executed. The rates of Rc/B adopted in simulations are 2.7, 5.4 and 8.1. The terms analyzed in this paper secondary flow velocity, streamwise velocity, the path of maximum steamwise velocity, deviation angle, and mass-shift velocity.

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Electrical characteristics of an optically controlled N-channel Si-MOSFET for possible application to OEICs on Si substrate

  • 백강현;임석진;임광만;김동명
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 1998년도 하계종합학술대회논문집
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    • pp.351-354
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    • 1998
  • In this paper, electrical characteristics of an n-channel Si MOSFET with L$_{s}$=0.6.mu.m under optical illumination are charaterized on wafer. Energetic photons with .gamma.=830nm, hv=1.494eV, P$_{opt}$=300mW are injected near the drain junction, the most photoresponsive region in the device, via optical fiber. We observed significantly increased drain current and transconductance, which is considered to be useful for the implementation of OEICs on silicon substrate, under optical control with P$_{opt}$=300mW. Optical power-dependent physical mechanisms responsible for the variation of electrical characteristics under optical input are also reported.d.d.d.

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Drain-current Modeling of Sub-70-nm PMOSFETs Dependent on Hot-carrier Stress Bias Conditions

  • Lim, In Eui;Jhon, Heesauk;Yoon, Gyuhan;Choi, Woo Young
    • JSTS:Journal of Semiconductor Technology and Science
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    • 제17권1호
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    • pp.94-100
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    • 2017
  • Stress drain bias dependent current model is proposed for sub-70-nm p-channel metal-oxide semiconductor field-effect transistors (pMOSFETs) under drain-avalanche-hot-carrier (DAHC-) mechanism. The proposed model describes the both on-current and off-current degradation by using two device parameters: channel length variation (${\Delta}L_{ch}$) and threshold voltage shift (${\Delta}V_{th}$). Also, it is a simple and effective model of predicting reliable circuit operation and standby power consumption.

밀리미터파 대역을 이용하는 차량간 DS-CDMD/QPSK 방식의 성능 분석 (Performance Analysis of Inter-Vehicle DS-CDMA/QPSK in Millimeter Wave-Band)

  • 김춘구;강희조;최용석
    • 한국정보통신학회:학술대회논문집
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    • 한국해양정보통신학회 2000년도 춘계종합학술대회
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    • pp.195-198
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    • 2000
  • 본 논문에서는 근거리 차량간통신(IVC)에서 DS-CDMA/QPSK 시스템의 성능을 분석하고 다중접속에 강한 장점을 지닌 60GHz 밀리미터파를 이용하여 첨단차량도로시스템(AVHS)의 플래툰주행에 적합한 One-Ray Rician 채널 모델에서의 패킷오율을 구하였다. 성능 개선 기법으로는 BCH 채널 부호화(255, 247, 1)와 MRC 다이버시티 수신기법을 동시에 채용했을 때 One-Ray Rician 페이딩 환경하에서 Rician 심도와 사용자 수의 변화에 따른 시스템의 오율 특성을 분석하고 차량간 거리에 따른 패킷 오율을 구하였다.

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다중경로 페이딩 전송로에서 직접시퀀스 확산대역 다원접속 시스템의 포착성능 (Acquisition performance of a direct-sequence spread-specturm multiple-access system in a multipath fading channel)

  • 김진영;이재홍
    • 한국통신학회논문지
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    • 제21권5호
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    • pp.1230-1239
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    • 1996
  • This paper analyzes matched-filter acquistion performance of a direct-sequence spread-specturm multiple-access system in a Rayleigh fading channel. For an application of multiple access system, multiple access interference is considered in the performance analysis. A signal flow graph technique is used to derive mean acquisition time in terms of detection and false alarm probabilities. As aresult of performance analysis, it is shown that mean acquisition time increases as fading rate becomes faster andthe numbre of users increases, and it decreases as a matched-filter length becomes logner. The variation of parameter values hs much influence on acquisition performance as SNR/chip becomes smaller.

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서브마이크론 MOSFET의 파라메터 추출 및 소자 특성 (1)

  • 서용진;장의구
    • E2M - 전기 전자와 첨단 소재
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    • 제7권2호
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    • pp.107-116
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    • 1994
  • In the manufacturing of VLSI circuits, variations of device characteristics due to the slight differences in process parameters drastically aggravate the performances of fabricated devices. Therefore, it is very important to establish optimal process conditions in order to minimize deviations of device characteristics. In this paper, we used one-dimensional process simulator, SUPREM-II, and two dimensional device simulator, MINIMOS 4.0 in order to extract optimal process parameter which can minimize changes of the device characteristics caused by process parameter variation in the case of short channel nMOSFET and pMOSFET device. From this simulation, we have derived the dependence relations between process parameters and device characteristics. Here, we have suggested a method to extract process parameters from design trend curve(DTC) obtained by these dependence relations. And we have discussed short channel effects and device limitations by scaling down MOSFET dimensions.

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Depositional Facies Analysis from Seismic Attributes: Implication of Reservoir Characterization

  • Park Yong-Joon
    • 한국석유지질학회:학술대회논문집
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    • 한국석유지질학회 1999년도 제6차 학술발표회 발표논문집
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    • pp.2-16
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    • 1999
  • This study includes structural analysis of the northern Pattani Basin, areal description of depositional facies, and their spatial relationships using 3-D seismic and well data. Well log data indicate that the representative depositional facies of the studied intervals are sandy, fluvial, channel-fill facies encased in shaly floodplain deposits. Seismic responses were predicted from a synthetic seismogram using a model of dominant depositional facies. Peak-to-trough amplitude and instantaneous frequency seismic attributes are used in depositional facies interpretation. Three Intervals A, B and C are interpreted on the successive stratal surfaces. The shallowest interval, A, is the Quaternary transgressive succession. Each stratal surface showed flow pattern variation of fluvial channel facies. Two transgressive cycles were identified in interval A. Interval B also indicated fluvial facies. Depositional facies architectures are described by interpreting seismic attributes on the successive stratal surfaces.

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