• 제목/요약/키워드: far field

검색결과 1,923건 처리시간 0.031초

타원형 지형점유에 적합한 내국용 위성 급전호온의 설계 및 제작

  • 김대영;홍재표;손현
    • 한국통신학회:학술대회논문집
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    • 한국통신학회 1984년도 추계학술발표회논문집
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    • pp.66-69
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    • 1984
  • A corrugated eiliptical horn which has the aperture dimensions of 60 x 30mm is designed and investigated experimenttally for 11Ghz - 13Ghz band. Experimental result is that the constructed horn produce on eiliptical far-field pattern with ratio of 1.63:1 - 1.81:1 for half-power beamwidth.

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판토그라프 주변의 유동 및 소음 특성에 관한 연구 (A Study on Aerodynamic and Aeroacoustic Characteristics around Pantograph)

  • 유승원;민옥기;박춘수;정흥채
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2000년도 춘계학술대회 논문집
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    • pp.529-536
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    • 2000
  • This paper describes the analysis of aerodynamics and the prediction of airflow induced noise around simplified pantograph. First, computational fluid dynamics (CFD) is conducted far several model to evaluate linear/nonlinear flow field characteristics due to high speed flow and the CFD results support the computational aeroacoustics. The accurate prediction of the aeroacoustic analysis is necessary for designers to control and reduce the airflow induced noise. We adopt the acoustic analogy based on Ffowcs Williams- Hawkings (FW-H) equation and predict aeroacoustic noise.

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Recent Advance of Flexible Organic Memory Device

  • Kim, Jaeyong;Hung, Tran Quang;Kim, Choongik
    • Journal of Semiconductor Engineering
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    • 제1권1호
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    • pp.38-45
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    • 2020
  • With the recent emergence of foldable electronic devices, interest in flexible organic memory is significantly growing. There are three types of flexible organic memory that have been researched so far: floating-gate (FG) memory, ferroelectric field-effect-transistor (FeFET) memory, and resistive memory. Herein, performance parameters and operation mechanisms of each type of memory device are introduced, along with a brief summarization of recent research progress in flexible organic memory.

복잡(複雜)한 탄층구조(炭層構造)에서의 이논전위곡선(理論電位曲線)의 계산(計算) (Theoretical Potential Calculation of Coal Seam in Various Structures)

  • 김웅수;서백수
    • 산업기술연구
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    • 제1권
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    • pp.27-33
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    • 1981
  • Due to intense tectonic activities and volcanic movements, coal mines exploration have been conflicted with problems so far. In this paper, computer calculation was specially applied for various model structures of inclined, anticlined and synclined coal beds. Of all these structures, the gradient of equipotential curves showed great as the dip of coal beds increases. Especially at synclined structure, the concaves appeared sharply in both sides of equipotential curves as the dip of coal beds increases. By above results, interpretation of coal exploration can be done by comparing field data one another.

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Hidden Monsters in the Submillimeter

  • Wang, Wei-Hao
    • 천문학회보
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    • 제37권2호
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    • pp.232.2-232.2
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    • 2012
  • Submillimeter Galaxies (SMGs) are high-redshift galaxies undergone extremely intense starbursts. Their UV radiation is heavily extinguished by dust and is re-radiated in the far-IR and submillimeter. They are thought to be progenitors of present-day giant elliptical galaxies and can be tracers of the highest density environment at high redshift. However, because of the low angular resolution of existing single-dish submillimeter telescopes, the progress in understanding the SMG population has been remarkably slow. In this talk, I will outline the outstanding issues in this field, and introduce our Submillimeter Array interferometric studies of SMGs. I will also discuss possible new research that will be enabled by next-generation instruments such as ALMA and LMT.

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환경친화형 주거단지 계획에 관한 기초조사 연구 - 전문가 의식조사를 중심으로 - (A Basic Study on the Planning of the Environment-Friendly Apartment Complex)

  • 정유선;유영신;윤정숙
    • 한국주거학회:학술대회논문집
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    • 한국주거학회 2001년도 학술발표대회논문집
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    • pp.27-32
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    • 2001
  • The purpose of this study is to accumulate basic data to establish planning direction and important planning factors for the environment-friendly apartment complex for sustainable development. For this purpose, the survey has been conducted to graduate students, architects and research experts in the field. The basic concept of planning factors far environment-friendly apartment complex are energy saving, resources saving, minimizing environment pollution, natural harmony, regional identity and pursuit of residents's health & amenity.

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GW급 UWB용 고전압 나노초 펄스 발생 (High Voltage Nanoseconds Pulse Generation for 1GW UWB radiation)

  • 김영배;이홍식
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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    • pp.2123-2125
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    • 2005
  • Ultra wide band electromagnetic energy can be transmitted to a far field by emitting the nanoseconds high voltage Pulse electromagnetic energy via an antenna. This UWB EM energy is expected to be used in post-packing pasteurization of food, detection of buried objects or underground water veins and caves and the treatment of waste water or polluted gas. The nanoseconds pulse forming for UWB generation using 500kV blumlein line and an ultrafast switch is mentioned.

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Neutron clustering in Monte Carlo iterated-source calculations

  • Sutton, Thomas M.;Mittal, Anudha
    • Nuclear Engineering and Technology
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    • 제49권6호
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    • pp.1211-1218
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    • 2017
  • Monte Carlo neutron transport codes generally use the method of successive generations to converge the fission source distribution to-and then maintain it at-the fundamental mode. Recently, a phenomenon called "clustering" has been noted, which produces fission distributions that are very far from the fundamental mode. In this study, a mathematical model of clustering in Monte Carlo has been developed. The model draws on previous work for continuous-time birth-death processes, as well as methods from the field of population genetics.

Environmental Tobacco Smoke의 이화학적 특성 (The physicochemical Characterization of ETS (Environmental Tobacco Smoke))

  • 이문수
    • 한국연초학회지
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    • 제17권1호
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    • pp.79-97
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    • 1995
  • On the basis of the literature, which is at present still scientific information improvable, the results of research done so far into the occurrence and analytical methodology of major markers of environmental tobacco smoke(ETS) have been summarized. Key areas addressed are: differences in physicochemical composition between mainstream smoke, sidestream smoke and ETS: techniques for field measurement of ETS: relationship between indoor air quality with ETS and its distribution view of US EPA and its problems: biological effects and concerning estimation of ETS exposure.

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소파제-초대형 부유식 해상구조물 운동 및 소파효율 해석 (Motion and Wave Elevation Analyses for Floating Breakwaters and a VLFS)

  • 홍도천;홍사영
    • 대한조선학회논문집
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    • 제41권3호
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    • pp.22-27
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    • 2004
  • Waveheight attenuation efficiencies of floating breakwaters in water of finite depth for a VLFS are studied numerically in accordance with the two body radiation-diffraction problem. Four different forms of the breaker are tested with a solid VLFS. The radiation-diffraction wave elevations between the breakwater and the VLFS are predicted directly instead of the far-field transmission-reflection coefficients of the breakwater.