• 제목/요약/키워드: mechanical characterization

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탄소나노튜브 필름을 이용한 투명 압저항체의 제작 및 특성 연구 (Fabrication and Characterization of Transparent Piezoresistors Using Carbon Nanotube Film)

  • 이강원;이정아;이광철;이승섭
    • 대한기계학회논문집A
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    • 제34권12호
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    • pp.1857-1863
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    • 2010
  • 본 논문에서는 탄소나노튜브 필름을 이용한 투명 압저항체의 제작 및 특성 연구를 수행하였다. 진공필터 방식으로 제작된 다양한 투과도를 가지는 탄소나노튜브 필름은 금층이 증착된 실리콘 기판위에서 사진식각 공정을 통해 패터닝이 된 후, 금층과 실리콘 기판의 약한 접착력으로 인해 실리콘 러버인 poly-dimethysiloxane (PDMS) 로 전사된다. 탄소나노튜브 필름의 압저항 특성을 분석하기 위해, 얇은 PDMS 멤브레인의 처짐에 대한 탄소나노튜브 필름의 저항 변화를 측정하여 10-20 의 개이지 팩터를 얻었으며, 인가 압력에 대한 저항 변화 실험을 수행하였다. 본 실험을 통하여 탄소나노튜브 필름은 폴리머 멤스의 다양한 응용분야에 투명한 압저항체로 사용될 수 있을 것으로 판단한다.

Characteristics of Thermo-Acoustic Emission from Composite Laminates during Thermal Load Cycles

  • Kim, Young-Bok;Park, Nak-Sam
    • Journal of Mechanical Science and Technology
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    • 제17권3호
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    • pp.391-399
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    • 2003
  • The thermo-acoustic emission (AE) technique has been applied for nondestructive characterization of composite laminates subjected to cryogenic cooling. Thermo-AE events during heating and cooling cycles showed a Kaiser effect. An analysis of the thermo-AE behavior obtained during the 1st heating period suggested a method for determining the stress-free temperature of the composite laminates. Three different thermo-AE types classified by a short-time Fourier transform of AE signals enabled to offer a nondestructive estimation of the cryogenic damages of the composites, in that the different thermo-AE types corresponded to secondary microfracturing in the matrix contacting between crack surfaces and some abrasive contact between broken fiber ends during thermal load cycles.

Characterization of Mechanical Properties of Boron Steel Sheet in Hot Bending Process with Various Parameters

  • 이양;강충길
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2009년도 추계학술대회 논문집
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    • pp.375-378
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    • 2009
  • Hot press forming is a new forming process which also names as hot stamping. It can greatly enhance the formability of forming parts. This paper researches the formability of boron steel sheet in hot bending process which is a kind of hot press forming. In the text, the influence of hot press forming processing parameters, such as the heating temperature, blank holding force, punch speed and punch and die radius, on the mechanics properties and microstructure of the hot bending parts was analyzed by tension test and the metallographic observation on the parts with various processing parameters. The relationship between blank holding force and punch load was also presented.

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A GNSS Interference Detection Method Based on Multiple Ground Stations

  • Kim, Sun Young;Kang, Chang Ho;Yang, Jeong Hwan;Park, Chan Gook;Joo, Jung Min;Heo, Moon Beom
    • Journal of Positioning, Navigation, and Timing
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    • 제1권1호
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    • pp.15-21
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    • 2012
  • For a GNSS receiver's robustness against RFI and the high accuracy of navigation solution in GNSS, interference source detection and mitigation are needed. In this paper, an adaptive lattice IIR notch filter is employed to track single-tone continuous wave and swept continuous wave interference signals, and an interference detection method is proposed. Furthermore, this paper presents interference source characterization algorithm using multiple ground stations' interference detection results. The measurement of the signal powers from each ground station is used to build weighting factors to estimate the type of the interference. The performance of interference detection algorithm is simulated for scenarios of GPS signal in the presence of single-tone continuous wave interference and swept continuous wave interference.

Characterization of electromechanical properties of Sn-Cu double layer stabilized GdBCO coated conductor tapes at 77 K

  • Shin, Hyung-Seop;Diaz, Mark Aangelo;Lee, Jae-Hun
    • 한국초전도ㆍ저온공학회논문지
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    • 제19권4호
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    • pp.26-30
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    • 2017
  • The promising characteristics of 2G high-temperature superconductor (HTS) coated conductor (CC) tapes have made it possible to apply to various electrical device applications. In this study, the mechanical and electromechanical properties of Sn-Cu double layer stabilized GdBCO CC tapes have been characterized. The stress and strain tolerances of $I_c$ in GdBCO CC tapes adopting stainless steel substrate were evaluated using $I_c$-strain measurement at 77 K under both uniaxial tension and monotonic bending conditions. The results were compared to the conventional single Cu layer stabilized CC tape. As a result, the Sn-Cu double layer stabilized GdBCO CC tapes showed somehow lower or comparable electromechanical properties as compared to the Cu stabilized CC tape ones.

Flame Synthesis of Silica-Coated Iron Oxide Nanoparticles and Their Characterization

  • Jun, Kimin;Yang, Sangsun;Lee, Jeonghoon;Pikhitsa, Peter V.;Choi, Mansoo
    • 한국입자에어로졸학회지
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    • 제9권4호
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    • pp.209-219
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    • 2013
  • We have used the modified diffusion flame burner to synthesize silica coated iron oxide nanoparticles having enhanced superparamagnetic property. Silica-encapsulated iron oxide particles were directly observed using a high resolution transmission electron microscope. From the energy dispersive X-ray spectroscopy (EDS) and zeta potential measurements, the iron oxide particles were found to be completely covered by a silica coating layer. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) measurements revealed that the iron oxide core consists of ${\gamma}-Fe_2O_3$ rather than ${\alpha}-Fe_2O_3$. Our magnetization measurements support this conclusion. Biocompatibility test of the silica-coated iron oxide nanoparticles is also conducted using the protein adsorption onto the coated particle.

임피던스 측정을 이용한 세포의 변형성 분석용 미소유체 칩 (Microfluidic chip for characterization of mechanical property of cell by using impedance measurement)

  • 김동일;최은표;최성식;박정열;이상호;윤광석
    • 센서학회지
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    • 제18권1호
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    • pp.42-47
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    • 2009
  • In this paper we propose a microfluidic chip that measures the mechanical stiffness of cell membrane using impedance measurement. The microfluidic chip is composed of PDMS channel and a glass substrate with electrode. The proposed device uses patch-clamp technique to capture and deform a target cell and measures impedance of deformed cells. We demonstrated that the impedance increased after the membrane stretched and blocked the channel.