• 제목/요약/키워드: Proximity effect

검색결과 275건 처리시간 0.041초

1.9 GHz 대 소형 역 F 안테나의 설계 및 제작 (Design and Manufacture of a Small Inverted F Antenna in 1.9 GHz band)

  • 유재욱;박병권;한상철;임인성;민경일;오승엽
    • 한국전자파학회논문지
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    • 제8권3호
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    • pp.297-309
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    • 1997
  • In this paper, A small inverted F Antenna with 1.9 GHz frequency band is studied theoretically, characterized by numerical analysis with computer and fabricated in order to use in the proximity sensor. Because of small space for antenna in proximity sensor, .lambda. /4 length plate and dielectric material are used to reduce the size of antenna and broaden the bandwidth. Finite ground body's affection is compensated by dielectric top loading effect which strengthen front direction power about 4 dB. Fabricated antenna is measured and the result is that resonant frequency is 1900.05 MHz, VSWR is 1.02, bandwidth is 194 MHz and input impedance is 50.45-j0.108 [ .ohm. ].

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측벽부근을 항해하는 선박과 측벽간의 상호 간섭력에 관한 연구 (A Study on the Hydrodynamic Interaction Forces between Ship and Bank Wall in the Proximity of Bank)

  • 이춘기;강일권
    • 수산해양기술연구
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    • 제40권1호
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    • pp.73-77
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    • 2004
  • It is well known that the hydrodynamic interaction forces between ship and bank wall affect ship manoeuvring motions. In this paper, the calculation method based on the slender body theory for estimation of the hydrodynamic interaction forces between ship and bank wall is investigated. The numerical simulations on hydrodynamic interaction force acting on a ship in the proximity of bank wall are carried out by using this theoretical method. The theoretical method used in this paper will be useful for practical prediction of ship manoeuvrability at the initial stage of design, for discussion of marine traffic control system and for automatic control system of ship in confined waterways.

The Relationships Between Children's Perceptions Toward Grandparents and Their Intimate Behavior

  • Jung, Min-Suk;Ko, Eun-Kyo;Rho, Joseph Y.;Lee, Seung-Hyun
    • International Journal of Contents
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    • 제5권4호
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    • pp.19-29
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    • 2009
  • This study is focused on the causal relationship between children's intimate behavior and the level of perception towards their grandparents. Their perceptions are related to factors such as proximity, similarity, superiority, favorableness, and self-disclosure. We clarified the relation between intimate behavior and perception using effect factors of children's behavior regarding their grandparents so that this study could be used as an elementary material in developing a solution to improve grandparent-grandchild relationship where the grandparent actively encourages grandchildren's intimate behavior. Regression analysis was used as a hypothesis testing method. The results indicated the following three points. First, perception factors affect active intimate behavior in the order of favorableness, superiority, self-disclosure, and similarity. Second, perception factors affect intimate behavior will in the order of favorableness, superiority, and self-disclosure. Lastly, it was shown that a child's active intimate behavior has an influence on their intimate behavior will.

A Numerical Study on Flow-Accelerated Corrosion in Two Adjacent Elbows

  • Yun, Hun;Hwang, Kyeongmo;Moon, Seung-Jae
    • Corrosion Science and Technology
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    • 제15권1호
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    • pp.6-12
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    • 2016
  • Flow-Accelerated Corrosion (FAC) is a well-known degradation mechanism that attacks the secondary piping in nuclear power plants. Since the Surry Unit 2 event in 1986, most nuclear power plants have implemented management programs to deal with damages in carbon and low-alloy steel piping. Despite the utmost efforts, damage induced by FAC still occurs in power plants around the world. In order to predict FAC wear, some computer programs were developed such as CHECWORKS, CICERO, and COMSY. Various data need to be input to these programs; the chemical composition of secondary piping, flow operating conditions and piping geometries. CHECWORKS, developed by the Electric Power Research Institute (EPRI), uses a geometry code to calculate geometry effects. Such a relatively simple geometry code is limited in acquiring the accuracy of FAC prediction. Recently, EPRI revisited the geometry code with the intention of updating it. In this study, numerical simulations were performed for two adjacent $90^{\circ}$ elbows and the results were analysed in terms of the proximity effect between the two adjacent elbows.

근접센서를 이용한 비접촉 방식의 출입문 감지제어 시스템 (A Contact-free type door control System with Proximity Switch)

  • 김승수;이기수;안청모;유주현
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2005년도 추계학술대회 논문집
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    • pp.1063-1070
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    • 2005
  • Number of subway train units that Seoul Metropolitan Subway Corporation as at September 2005 is 1.944 on 4 routes from 60 units at the time of commencement of operation, having grown exponentially. Along with increase in the number of passengers the role of subway as safer and expedient means of transportation is now being required. Furthermore, the Corporation has been researching on means of improving the safety and reliability of subway entry/exit doors which has become an essential task and directly effect the safety of the passengers. In this Study, has developed sensory control system for the entry/exit door of the subway train using non-contact proximity sensor as a part of review of and measures against various issues of entry/exit door of the subway trains currently under operation. In addition, this sensor system was verified through test production and tests. If this technology becomes commercialized and practically utilized in the future, it would be able to make definite contribution to the safer transportation of passengers.

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점성-비점성 유동 반복계산 방법을 이용한 2차원 자동차모형의 공력 특성 예측 (Predicting aerodynamic characteristics of two-dimensional automobile shapes in ground proximity using an iterative viscous-potential flow technique)

  • 최도형;최철진
    • 오토저널
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    • 제8권1호
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    • pp.52-61
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    • 1986
  • An iterative viscous-potential flow procedure has been developed and used to predict aerodynamic characteristics of automobiles in ground proximity. The method is capable of predicting the effects of separated flows. The viscous-potential flow iteration procedure provides the connection between potential flow, boundary layer and wake modules. The separated wake is modeled in the potential flow analysis by thin sheets across which exists a jump in velocity potential. The ground effect is properly accounted for by placing a body image in the potential flow calculation. The agreement between theory and experiment is good and, thus, demonstrates that the method can be used in the preliminary design stage.

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Phase Coherence in Mesoscopic Kondo Wires

  • Eom, Jong-Hwa;Ki, Dong-Keun;Shin, Yun-Sok;Lee, Hu-Jong
    • 한국초전도학회:학술대회논문집
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    • 한국초전도학회 2004년도 High Temperature Superconductivity Vol.XIV
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    • pp.48-48
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    • 2004
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