• Title/Summary/Keyword: Line array

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Design of Forming Path for Concave Steel Plate Using the Line Array Roll Set (선형 배열 롤 셋을 이용한 오목형상 강판 성형경로 설계)

  • Roh, H.J.;Kim, K.H.;Shim, D.S.;Yang, D.Y.;Chung, S.W.;Han, M.S.
    • Transactions of Materials Processing
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    • v.17 no.7
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    • pp.491-495
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    • 2008
  • Incremental forming path to manufacture a thick concave steel plate using the line array roll set is designed. To find the optimum forming path, the forming processes are simulated by the finite element method. A general-purpose commercial software, MSC MARC is used. A modeling with 8-node hexahedral elastic-plastic solid is performed to predict accurate springback and the analysis process was composed of 18 passes. The proposed forming paths are verified through experiments carried out in the prototype line array roll set. It is found that the process can be successfully applied to the fabrication of the dual curvature ship hull plate.

The Design of microstrip line-probe feeding patch array antenna (마이크로스트립 라인-프로브 급전 패치 배열 안테나의 설계)

  • 박종렬;이윤경;윤현보
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • 2002.11a
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    • pp.285-289
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    • 2002
  • In this paper, microstrip line-probe feeding patch array antenna with center frequency 5.8㎓ is designed and manufactured. The microstrip line - probe feeding structure has broadband characteristic and be able to modify the array structure for improving antenna gain. In this result, microstrip line-probe feeding patch array antenna has 17.6% bandwidth and 8㏈i antenna gain, respectively.

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Adaptive Beamforming Method for Turning Towed Line Array SONAR (회전하는 견인 선배열 소나의 적응 빔 형성 기법)

  • Lee, Seokjin;Park, Kyung-Min;Chung, Suk-Moon
    • The Journal of the Acoustical Society of Korea
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    • v.33 no.6
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    • pp.383-391
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    • 2014
  • In order to detect underwater acoustic signals, various SONAR array types have been developed, including towed line array SONAR system (TASS). However, the TASS suffers from performance degradation which is caused by aperture deformation during a turn, because the TASS have a long-aperture array. A parabolic array model for turning TASS have been developed to solve the degradation problem occurred during a turn. In this paper, adaptive beamforming system is developed using the parabolic TASS model to cancel interference signals. The developed beamforming system is based on generalized sidelobe canceller (GSC) structure and self-tuning adaptive algorithm.

The Design of Microstrip Array Antenna using Chebyscheff Polynomial (Chebyscheff 다항식을 이용한 Microstrip Array Antenna의 설계)

  • 이종악
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.14 no.5
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    • pp.542-548
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    • 1989
  • Rectangular microstrip antenna array using Chebyscheff polynomial is designed. The required relative currents in the rectangular microstrip array antenna are 1:2:2:1. The input admittance and returen loss of array antenna are calculated from transmission line model circuit include feed line. The calculated resonant frequency valused are in good agreement with measured values. Also, the sharp beam scanning characteristic of perfect electronic method is presented.

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Coupled Line Phase Shifters and Its Equivalent Phase Delay Line for Compact Broadband Phased Array Antenna Applications

  • Han, Sang-Min;Kim, Young-Sik
    • Journal of electromagnetic engineering and science
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    • v.3 no.1
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    • pp.62-66
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    • 2003
  • Novel coupled line phase shifters and its equivalent phase delay line for compact broadband phased array antennas are proposed. These phase control circuits are designed to be less complex, small size and to use a less number of active devices. The phase shifter is able to control a 120$^{\circ}$ phase shift continuously, and the phase delay line for a reference phase has a fixed 60$^{\circ}$ shifted phase. Both have the low phase error of less than $\pm$3.5$^{\circ}$ and the low gain variations of less than 1 ㏈ within the 300 MHz bandwidth. These proposed circuits are adequate to form the efficient beam-forming networks with compactness, broadband, less complexity, and low cost.

Left/Right Bearing Discrimination with Adaptive Cardioid Beamforming (적응 카디오이드 빔 형성을 이용한 좌/우 방위 분리 기법)

  • 손윤준;천승용;김기만
    • The Journal of the Acoustical Society of Korea
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    • v.22 no.6
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    • pp.489-495
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    • 2003
  • Single towed line array receiver contains an ambiguity on conjugate bearings because of lacking aperture in transverse direction. To solve the left/right bearing ambiguity of line array receiver this paper proposed using single line array with fixed cardioid beam. Fixed cardioid beam has problem about back beam gain exists for steering beam inherent. Back beam is makes form on direction that is different from actually source so that reduced the performance of left/right bearing discrimination. In this paper, line way with adaptive cardioid beam for resolve problem of back beam gain is proposed. So the proposed method has more improved left/right bearing discrimination than fixed cardioid beam, Simulation results show the performance of the proposed method.

Defect Detection Using Focused Lamb Waves Generated by Laser (집속형 레이저 유도초음파에 의한 결함검출)

  • Kim, Hong-Joon;Jung, Ji-Hong;Ha, Job;Jhang, Kyung-Young
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.774-779
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    • 2003
  • Arc-shaped line array slits have been used for the laser generation of focused Lamb waves. The spatially expanded Nd:YAG pulse laser was illuminated through the arc-shaped line array slit on the surface of a sample plate to generate the Lamb waves of the same pattern as the slit. Then the generated Lamb waves were focused at the point of which distance from the slit position is dependent on the curvature of slit arc. The proposed method showed better spatial resolution than the conventional linear array slit in the detection of laser machined linear defect and drill machined circular defect on aluminum plates of 1mm thickness.

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On Line Monitoring and Diagnosis Technique for the Array of Photovoltaic Energy System (태양광 발전시스템 전지모듈의 온라인 감시 진단 시스템 개발)

  • Lee, Jong-Pil;Ji, Pyeong-Shik;Byun, Sang-Zoon;Lim, Jae-Yoon
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.56 no.4
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    • pp.168-172
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    • 2007
  • The global environment deteriorating which originated from using of fossil fuel is an serious problem for human being to solve. The photovoltaic energy has been considered as a solution. In advanced countries, research and development for photovoltaic(PV) energy system is carrying on. Once installed, a PV array requires maintenance and fault diagnosis other than an occasional cleaning. In this research, the proposed system monitor and diagnosis the output of PV array by on-line for maintenance of PV power plant. The validity of proposed system is verified using sample system.

Laser Generation of Focused Lamb Waves

  • Jhang, Kyung-Young;Kim, Hong-Joon;Kim, Hyun-Mook;Ha, Job
    • Journal of the Korean Society for Nondestructive Testing
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    • v.22 no.6
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    • pp.637-642
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    • 2002
  • An arc-shaped line array slit has been used for the laser generation of focused Lamb waves. The spatially expanded Nd:YAG pulse laser was illuminated through the arc-shaped line array slit on the surface of a sample plate to generate the Lamb waves of the same pattern as the slit. Then the generated Lamb waves were focused at the focal point of which distance from the slit position is dependent on the curvature of slit arc. The proposed method showed better spatial resolution than the conventional linear array slit in the detection of laser machined linear defect and drill machined circular defect on aluminum plates of 2mm thickness. Using the focused waves, we could detect the linear defect and the circular defect with the improvement of spatial resolution. The method can also be combined with the scanning mechanism to get an image just like by the scanning acoustic microscope(SAM).

Effects of fin pitch and array of the frost laver growth on extended surface of a heat exchanger (열교환기 표면에서의 서리층 성장에 대한 휜 피치와 배열의 영향)

  • Yang, Dong-Keun;Lee, Kwan-Soo
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.1461-1466
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    • 2003
  • This paper presents the effects of the fin array and pitch on the frost layer growth of a heat exchanger. The numerical results are compared with experimental data of a cold plate to validate the present model, and agree well with experimental data within a maximum error of 8%. The characteristics of the frost formation on staggered fin array are somewhat different from those of in-line array. The frost layer at the first fin of the in-line array grows rapidly, compared to second fin, whereas the difference of the frost layer growth between the fins of the staggered array is small. For fin pitch below 10 mm, the frost layer growth of second fin in the staggered array is affected by that of first fin. The frost layer growth and heat transfer of single fin deteriorate with decreasing fin pitch regardless of fin array, however, the thermal performance of a heat exchanger, considering increase of heat surface area, becomes better.

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