• Title/Summary/Keyword: pcbs

검색결과 498건 처리시간 0.026초

PCB 선로에서 복사되는 불요전자파를 억제하기 위한 기술 (The EMI Suppression Technology for Radiated Emissions from PCB Traces)

  • 박이섭;이중근
    • 한국전자파학회논문지
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    • 제11권7호
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    • pp.1121-1127
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    • 2000
  • PCB에서의 불요전자파 복사를 줄이기 위하여 많은 방법들이 이용되고 있으나, 본 논문에서는 영상평면을 적용하여 불요 전자파 복사를 줄이는 방법을 제시하였다. PCB에서의 영상평면 효과를 해석하기 위한 모델을 제시하였으며, FEM(Finite Element Method)으로 시뮬레이션을 한 후, 전계 프로브를 사용하여 불요 전자파의 세기를 측정하였다. 그 결과 PCB에서 복사되는 불요전자파의 세기는 영상평면의 폭과 간격에 따라 다르게 나타나며 측정한 결과와 시뮬레이션 결과가 유사한 것을 알 수 있었다. 그러므로 PCB에서 복사되는 불요전자파를 억제하기 위하여 영상평면을 적절히 사용한다면 EMI 저감 대책면에서 효과적이라는 것을 알 수 있었다.

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Power Integrity and Shielding Effectiveness Modeling of Grid Structured Interconnects on PCBs

  • Kwak, Sang-Keun;Jo, Young-Sic;Jo, Jeong-Min;Kim, So-Young
    • JSTS:Journal of Semiconductor Technology and Science
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    • 제12권3호
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    • pp.320-330
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    • 2012
  • In this paper, we investigate the power integrity of grid structures for power and ground distribution on printed circuit board (PCB). We propose the 2D transmission line method (TLM)-based model for efficient frequency-dependent impedance characterization and PCB-package-integrated circuit (IC) co-simulation. The model includes an equivalent circuit model of fringing capacitance and probing ports. The accuracy of the proposed grid model is verified with test structure measurements and 3D electromagnetic (EM) simulations. If the grid structures replace the plane structures in PCBs, they should provide effective shielding of the electromagnetic interference in mobile systems. An analytical model to predict the shielding effectiveness (SE) of the grid structures is proposed and verified with EM simulations.

Development of a Virtual Frisch-Grid CZT Detector Based on the Array Structure

  • Kim, Younghak;Lee, Wonho
    • Journal of Radiation Protection and Research
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    • 제45권1호
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    • pp.35-44
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    • 2020
  • Background: Cadmium zinc telluride (CZT) is a promising material because of a high detection efficiency, good energy resolution, and operability at room temperature. However, the cost of CZT dramatically increases as its size increases. In this study, to achieve a large effective volume with relatively low cost, an array structure comprised of individual virtual Frisch-grid CZT detectors was proposed. Materials and Methods: The prototype consisted of 2 × 2 CZTs, a holder, anode and cathode printed circuit boards (PCBs), and an application-specific integrated circuit (ASIC). CZTs were used and the non-contacting shielding electrode method was applied for virtual Frisch-grid effect. An ASIC was used, and the holder and the PCBs were fabricated. In the current system, because the CZTs formed a common cathode, a total of 5 channels were assigned for data processing. Results and Discussion: An experiment using 137Cs at room temperature was conducted for 10 minutes. Energy and timing information was acquired and the depth of interaction was calculated by the timing difference between the signals of both electrodes. Based on obtained three-dimensional position information, the energy correction was carried out, and as a result the energy spectra showed the improvements. In addition, a Compton image was reconstructed using the iterative method. Conclusion: The virtual Frisch-grid CZT detector based on the array structure was developed and the energy spectra and the Compton image were successfully acquired.

Earthworm Enhanced Bioaugmentation of PCB Contaminated Soil

  • Crowley, David E.;Luepromchai, Ekawan;Singer, Andrew S.;Yang, Chang Sool
    • 한국미생물생명공학회:학술대회논문집
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    • 한국미생물생명공학회 2000년도 Proceedings of 2000 KSAM International Symposium and Spring Meeting
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    • pp.100-107
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    • 2000
  • In a recently developed strategy for in-situ treatment of polychlorinated biphenyls (PCB), bioaugmentation was used in conjunction with a surfactant, sorbitan trioleate, as a carbon source for the degrader bacteria, along with the monoterpene, carvone, and salicylic acid as inducing substrates. Two bacteria were used for soil inoculants, including Arthrobacter sp. st. B1B and Ralstonia eutrophus H850. This methodology achieved 60% degradation of PCBs in Aroclor 1242 after 18 weeks in soils receiving 34 repeated applications of the degrader bacteria. However, an obvious limitation was the requirement for soil mixing after every soil inoculation. In the research reported here, bioaugmentation and biostimulation treatment strategies were modified by using the earthworm, Pheretima hawayana, as a vector for dispersal and mixing of surface-applied PCB-degrading bacteria and soil chemical amendments. Changes in microbial biomass and microbial community structure due to earthworm effects were examined using DNA extraction and PCR-DGGE of 16S rDNA. Results showed that earthworms effectively promoted biodegradation of PCBs in bioaugmented soils to the same extent previously achieved using physical soil mixing, and had a lesser, but significant effect in promoting PCB biodegradation in biostimulated soils treated with carvone and salicylic acid. The effects of earthworms were speculated to involve many interacting factors including increased bacterial transport to lower soil depths, improved soil aeration, and enhanced microbial activity and diversity.

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Direct Write 기술을 이용한 3DCD의 제작 (Fabrication of 3D-Printed Circuit Device using Direct-Write Technology)

  • 윤해룡;김호찬;이인환
    • 한국기계가공학회지
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    • 제15권2호
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    • pp.1-8
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    • 2016
  • Generally, electrical circuits are fabricated as Printed Circuit Boards (PCBs) and mounted on the casing of the product. Additionally, this requires many other parts and some labor for assembly. Recently, molding technology has increasingly been applied to embed simple circuits in plastic casing. The technology is called a Molded Interconnected Device (MID). By using this technology, PCB fabrication can be replaced by molding, and much of the corresponding assembly process for PCBs can be eliminated if the circuit is simple enough for molding. Furthermore, as the improvement of conductive materials and printing technologies of simple electric circuits can be printed directly on the casing part, this also reduces the complexity of the product design and production cost. Therefore, this paper introduces a new MID fabrication process using direct 3D printing technology. Additionally, it is applied to an automotive part of a cruise control switch. The methodology and design are shown.