• Title, Summary, Keyword: Acoustic and SEM measurement

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Nondestructive Damage Sensitivity for Functionalized Carbon Nanotube and Nanofiber/Epoxy Composites Using Electrical Resistance Measurement and Acoustic Emission (전기저항 측정과 음향방출을 이용한 표면 처리된 탄소 나노튜브와 나노 섬유 강화 에폭시 복합재료의 비파괴적 손상 감지능)

  • Kim, Dae-Sik;Park, Joung-Man;Kim, Tae-Wook
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.42-45
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    • 2003
  • Nondestructive damage sensing and mechanical properties for acid-treated carbon nanotube (CNT) and nanofiber (CNF)/epoxy composites were investigated using electro-micromechanical technique and acoustic emission (AE). Carbon black (CB) was used to compare to CNT and CNF. The results were compared to the untreated case. The fracture of carbon fiber was detected by nondestructive acoustic emission (AE) relating to electrical resistivity under double-matrix composites test. Sensing for fiber tension was performed by electro-pullout test under uniform cyclic strain. The sensitivity for fiber damage such as fiber fracture and fiber tension was the highest for CNT/epoxy composites. Reinforcing effect of CNT obtained from apparent modulus measurement was the highest in the same content. For surface treatment case, the damage sensitivity and reinforcing effect were higher than those of the untreated case. The results obtained from sensing fiber damage were correlated with the morphological observation of nano-scale structure using FE-SEM. The information on fiber damage and matrix deformation and reinforcing effect of carbon nanocomposites could be obtained from electrical resistivity measurement as a new concept of nondestructive evaluation.

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A Study on Acoustic Emission Characteristics of MCrAlY Coated Material by Vacuum Plasma Spray Process (진공 플라즈마 용사공정에 의한 MCrAlY코팅재의 음향방출 신호 특성 연구)

  • 박진효;이구현;예경환;김정석;강명창
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.921-924
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    • 2004
  • This paper is to investigate a crack for plasma sprayed MCrAlY coated material by acoustic emission method in 4-point bending test. The CoNiCrAlY is coated on Inconel-718 by vacuum plasma spray process. Micro-hardness measurement was conducted by means of Micro Vickers-hardness indentor. The porosity of coating layer was measured using a SEM and Image Analyzer. AE monitoring system is composed of PICO type sensor, a wide band preamplifier(40dB), a PC and AE DSP(16/32 PAC) board. The AE count, Hit and energy of coating specimens is measured according to coating thickness.

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Nondestructive Damage Sensitivity of Carbon Nanotube and Nanofiber/Epoxy Composites Using Electro-Micromechanical Technique and Acoustic Emission (Electro-Micromechanical 시험법과 음향방출을 이용한 탄소 나노튜브와 나노섬유 강화 에폭시 복합재료의 비파괴적 손상 감지능)

  • Kim, Dae-Sik;Park, Joung-Man;Lee, Jae-Rock;Kim, Tae-Wook
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.117-120
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    • 2003
  • Electro-micromechanical techniques were applied using four-probe method for carbon nanotube (CNT) or nanofiber (CNF)/epoxy composites with their content. Carbon black (CB) was used to compare with CNT and CNF. The fracture of carbon fiber was detected by nondestructive acoustic emission (AE) relating to electrical resistivity for double-matrix composites test. Sensing for fiber tension was performed by electro-pullout test under uniform cyclic strain. The sensitivity for fiber damage such as fiber fracture and fiber tension was the highest for CNT/epoxy composites, and in CB case they were the lowest compared with CNT and CNF. Reinforcing effect of CNT obtained from apparent modulus measurement was the highest in the same content. The results obtained from sensing fiber damage were correlated with the morphological observation of nano-scale structure using FE-SEM. The information on fiber damage and matrix deformation and reinforcing effect of carbon nanocomposites could be obtained from electrical resistivity measurement as a new concept of nondestructive evaluation.

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Thickness Measurement of Ni Thin Film Using Dispersion Characteristics of a Surface Acoustic Wave (표면파의 분산 특성을 이용한 Ni 박막의 두께 측정)

  • Park, Tae-Sung;Kwak, Dong-Ryul;Park, Ik-Keun;Kim, Miso;Lee, Seung-Seok
    • Journal of the Korean Society for Nondestructive Testing
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    • v.34 no.2
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    • pp.171-175
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    • 2014
  • In this study, we suggest a method to measure the thickness of thin films nondestructively using the dispersion characteristics of a surface acoustic wave propagating along the thin film surface. To measure the thickness of thin films, we deposited thin films with different thicknesses on a Si (100) wafer substrate by controlling the deposit time using the E-beam evaporation method. The thickness of the thin films was measured using a scanning electron microscope. Subsequently, the surface wave velocity of the thin films with different thicknesses was measured using the V(z) curve method of scanning acoustic microscopy. The correlation between the measured thickness and surface acoustic wave velocity was verified. The wave velocity of the film decreased as the film thickness increased. Therefore, thin film thickness can be determined by measuring the dispersion characteristics of the surface acoustic wave velocity.

A Study on properties of ZnO thin film for Film Bulk Acoustic Resonator (FBAR) application (FBAR 응용을 위한 ZnO 박막의 특성에 대한 연구)

  • Jeong, Young-Hak;Lee, Kyu-Il;Kim, Eun-Kwon;Lee, Jong-Duk;Song, Joon-Tae
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.688-692
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    • 2004
  • In this paper, zinc oxide (ZnO) films with c-axis (002) orientation have been successfully deposited on the Al/Si substrate by rf magnetron sputtering method. The deposited films were characterized by substate temperature. Physical and structural properties of the deposited films were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM) measurement. Electrical Properties of the deposited films were investigated by 4-poing probe and LCR meter measurement. The optimal condition in this experimental result was found at foot of the substrate temperature and shown good film quality for FBAR application.

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A Study on Characterization of P-N Junction Using Silicon Direct Bonding (실리콘 직접 본딩에 의한 P-N 접합의 특성에 관한 연구)

  • Jung, Won-Chae
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.30 no.10
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    • pp.615-624
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    • 2017
  • This study investigated the various physical and electrical effects of silicon direct bonding. Direct bonding means the joining of two wafers together without an intermediate layer. If the surfaces are flat, and made clean and smooth using HF treatment to remove the native oxide layer, they can stick together when brought into contact and form a weak bond depending on the physical forces at room temperature. An IR camera and acoustic systems were used to analyze the voids and bonding conditions in an interface layer during bonding experiments. The I-V and C-V characteristics are also reported herein. The capacitance values for a range of frequencies were measured using a LCR meter. Direct wafer bonding of silicon is a simple method to fuse two wafers together; however, it is difficult to achieve perfect bonding of the two wafers. The direct bonding technology can be used for MEMS and other applications in three-dimensional integrated circuits and special devices.