• Title/Summary/Keyword: Piezoelectric layer

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Experimental Study on Upstream Fueled Cavity Flame-Holder Scramjet Engine (상류 분사 공동 화염 지지부를 가지는 스크램제트 엔진에 관한 실험적 연구)

  • Jeung, In-Seuck;O'Byrne, Sean;Houwing, A.F.P.;Jeong, Eun-Ju
    • 한국연소학회:학술대회논문집
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    • 2006.04a
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    • pp.197-204
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    • 2006
  • The model cavity scramjet engine experiments are carried out using T3 free-piston shock tunnel. Upstream hydrogen fuel is injected before the cavity with different injection pressure. OH planar laser-induced fluorescence is used to investigate the combustion zone and piezoelectric pressure transducers are used to define the pressure rise due to the combustion. Main combustion region is a mixing layer which is between air and fuel. Also high OH fluorescence signal is appeared in the shear layer above the cavity in high equivalence ratio. From the OH signal in the cavity, this fuel injection system can be a role as a flame- holder.

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A Study on PZT-5A Probe for Nondestructive Inspection (비파괴검사를 위한 PZT 5A 탐촉자에 관한 연구)

  • 황현석;정규원;이종덕;송준태
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1996.11a
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    • pp.245-248
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    • 1996
  • In this study, piezoelectric transducers were designed and manufactured using PZT-5A which had relatively high electromechanical coefficient, NDT system was developed with was able to inspect automatically using stepping motors, PC-Lab, and PC-Scope The optimum design conditions for NDT were presented and verified comparing PZT-5A probes with comercial probes. It was proved with comercial probes. It was proved by simulation and experiments that Epoxy is good as material of matching and backing layers. The envelope was reduced 60% with matching layer and 76% with matching and backing layer. NDT was successfully carried out for aluminum test pieces. Distance error of PZT-5A probe was 2.8%.

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Dynamic behavior of piezoelectric bimorph beams with a delamination zone

  • Zemirline, Adel;Ouali, Mohammed;Mahieddine, Ali
    • Steel and Composite Structures
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    • v.19 no.3
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    • pp.759-776
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    • 2015
  • The First Order Shear Deformation Theory (FOSDT) is considered to study the dynamic behavior of a bimorph beam. A delamination zone between the upper and the lower layer has been taken into consideration; the beam is discretised using the finite elements method (FEM). Several parameters are taken into consideration like structural damping, the geometry, the load nature and the configurations of the boundary conditions. Results show that the delamination between the upper and the lower layer affects considerably the actuation.

Fabrication and Characterization of Multi-layered Thick Films by Room Temperature Powder Spray in Vacuum Process (상온 진공 분말 분사 공정을 이용한 다층 박막 소재의 제조 및 전기적 특성)

  • Ryu, Jung-Ho;Ahn, Cheol-Woo;Kim, Jong-Woo;Choi, Jong-Jin;Yoon, Woon-Ha;Hahn, Byung-Dong;Choi, Joon-Hwan;Park, Dong-Soo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.25 no.8
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    • pp.584-592
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    • 2012
  • Room temperature powder spray in vacuum process, so called Aerosol deposition (AD) is a room temperature (RT) process to fabricate thick and dense ceramic films, based on collision of solid ceramic particles. This technique can provide crack-free dense thin and thick films with thicknesses ranging from sub micrometer to several hundred micrometers with very fast deposition rates at RT. In addition, this technique is using solid particles to form the ceramic films at RT, thus there is few limitation of the substrate and easy to control the compositions of the films. In this article, we review the progress made in synthesis of piezoelectric thin/thick films, multi-layer structures, NTC thermistor thin/thick films, oxide electrode thin films for actuators or sensor applications by AD at Korea Institute of Materials Science (KIMS) during the last 4 years.

Novel Enhanced Flexibility of ZnO Nanowires Based Nanogenerators Using Transparent Flexible Top Electrode

  • Gang, Mul-Gyeol;Ha, In-Ho;Kim, Seong-Hyeon;Jo, Jin-U;Ju, Byeong-Gwon;Lee, Cheol-Seung
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.490.1-490.1
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    • 2014
  • The ZnO nanowire (NW)-based nanogenerators (NGs) can have rectifying current and potential generated by the coupled piezoelectric and semiconducting properties of ZnO by variety of external stimulation such as pushing, bending and stretching. So, ZnO NGs needed to enhance durability for stable properties of NGs. The durability of the metal electrodes used in the typical ZnO nanogenerators(NGs) is unstable for both electrical and mechanical stability. Indium tin oxide (ITO) is used as transparent flexible electrode but because of high cost and limited supply of indium, the fragility and lack of flexibility of ITO layers, alternatives are being sought. It is expected that carbon nanotube and Ag nanowire conductive coatings could be a prospective replacement. In this work, we demonstrated transparent flexible ZnO NGs by using CNT/Ag nanowire hybrid electrode, in which electrical and mechanical stability of top electrode has been improved. We grew vertical type ZnO NW by hydrothermal method and ZnO NW was coated with hybrid silicone coating solution as capping layer to enhance adhesion and durability of ZNW. We coated the CNT/Ag nanowire hybrid electrode by using bar coating system on a capping layer. Power generation of the ZnO NG is measured by using a picoammeter, a oscilloscope and confirmed surface condition with FE-SEM. As a results, the NGs using the CNT/Ag NW hybrid electrode show 75% transparency at wavelength 550 nm and small change of the resistance of the electrode after bending test. It will be discussed the effect of the improved flexibility of top electrode on power generation enhancement of ZnO NGs.

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Study for increasing property of piezoelectric energy harvester using multi-layer ceramic (적층형 압전세라믹을 이용한 에너지 하베스터의 특성 향상)

  • Kim, Hyung-Chan;Song, Hyun-Cheol;Kang, Chong-Yon;Kang, Jin-Kyu;Ju, Byeong-Kwon;Yoon, Seok-Jin
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.06a
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    • pp.51-51
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    • 2008
  • 최근 센서, 전자기술의 발달은 소형 센서 기기의 구동에 필요한 파워를 줄여 주변의 진동이나 온도차등에서의 작은 에너지로도 센서 등의 소형 전자기기의 구동을 가능하게 했다. 이에 따라 전자기기의 구동에너지로써 에너지 하베스팅이 많은 관심을 받고 있다. 압전 효과를 이용하여 주변의 진동에너지를 전기에너지로 변화 시키는 압전에너지 하베스터는 온도차이나 태양광, 바람등과는 달리 날씨나 구동조건에 큰 영항을 받지 않는 장점과 그 크기가 비교적 소형이라는 장점이 있어 많은 연구가 진행되고 있다. 에너지 하베스터에서 생산된 에너지를 사용하기 위해서는 생산된 에너지를 저장장치에 저장해야 한다. 저장장치에 저장하기 위해서는 일정 이상의 전압과 많은 양의 전류가 있는 것이 효과적이다. 하지만 압전 세라믹의 출력 특성은 전압이 크고, 출력 전류가 작은 특성을 지지고 있어 충전 속도가 느리다는 문제점이 있다. 압전세라믹에서 발생되는 에너지는 세라믹의 두께와 세라믹의 전극면적에 비례하는데 각각 세라믹의 두께는 출력 전압에 영향을 주며, 세라믹의 전극면적은 발생하는 전하량에 영항을 준다. 이러한 압전체의 특징을 이용하여 본 연구에서는 압전체의 출력특성의 향상을 위하여 $10\times35mm^2$ 크기의 적층 세라믹을 제작하여 압전에너지 하베스터를 제작하였다. 적층 압전세라믹을 이용한 에너지 하베스터에서 3.5m/$s^2$ 24.6 ${\mu}m$의 진동에서 발생전압 2.14 V 에 발생전류 252 ${\mu}A$의 특성을 얻을 수 있었다.

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Study on Relation of Optimum Resonant Frequencies between Piezo Ceramic and Matching Layer (피에조 세라믹과 매칭레이어와의 최적 공진주파수 관계에 대한 연구)

  • Kim, Kwon-Se;Choi, Doo-Seuk;Kim, Young-Choon;Cho, Jae-Ung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.7
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    • pp.3191-3196
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    • 2013
  • Ultrasonic transducer is the sensor which is measuring distance. Piezo ceramic of ultrasonic sensor and adhesive technique of matching layer are the most core techniques. With the study of relation on matching layer which takes off the ultrasonic wave into the air, this paper aims to find the second useful frequency as the results which can be changed are extracted in case piezo ceramic and matching layer are bonded. And the experiment is done with piezo ceramic as real piezoelectric element and matching layer of chemical wood. OD of piezo ceramic has designed by ${\Phi}50{\times}3T$ and OD of matching layer is designed by ${\Phi}62{\times}12t$ with ${\lambda}=1/4$. Acoustic impedance is generated at the most optimum resonant frequency of 53 Khz. As experimental result, more available frequency can be generated by using the adhesive close to solid than the flexible one.

Enhanced Crystallinity of Piezoelectric Polymer via Flash Lamp Annealing (플래시광 열처리를 통한 압전 고분자의 결정성 향상 연구)

  • Donghun Lee;Seongmin Jeong;Hak Su Jang;Dongju Ha;Dong Yeol Hyeon;Yu Mi Woo;Changyeon Baek;Min-Ku Lee;Gyoung-Ja Lee;Jung Hwan Park;Kwi-Il Park
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.37 no.4
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    • pp.427-432
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    • 2024
  • The polymer crystallization process, promoting the formation of ferroelectric β-phase, is essential for developing polyvinylidene fluoride (PVDF)-based high-performance piezoelectric energy harvesters. However, traditional high-temperature annealing is unsuitable for the manufacture of flexible piezoelectric devices due to the thermal damage to plastic components that occurs during the long processing times. In this study, we investigated the feasibility of introducing a flash lamp annealing that can rapidly induce the β-phase in the PVDF layer while avoiding device damage through selective heating. The flash light-irradiated PVDF films achieved a maximum β-phase content of 76.52% under an applied voltage of 300 V and an on-time of 1.5 ms, a higher fraction than that obtained through thermal annealing. The PVDF-based piezoelectric energy harvester with the optimized irradiation condition generates a stable output voltage of 0.23 V and a current of 102 nA under repeated bendings. These results demonstrate that flash lamp annealing can be an effective process for realizing the mass production of PVDF-based flexible electronics.

Modified Piezoelectric Ceramics for Portable Ultrasonic Medical Probe Application (휴대용 의료 초음파 프로브 적용을 위한 압전체 제조 및 특성)

  • Kang, Dong Heon;Chae, Mi Na;Hong, Se Won
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.29 no.8
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    • pp.483-488
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    • 2016
  • Ultrasound imaging by using piezoelectric materials, such as lead zirconium titanate (PZT) has been one of the most preferred modes of imaging in the medical field due to its simple, low cost and non-ionizing radiation in comparison to other imaging techniques. Recently, the market demand for portable ultrasound is becoming larger with applications in developing countries, disaster area, military, and emergency purposes. However, most of ultrasound probes used is bulky and high power consumable, so unsuitable for such applications. In this study, the 3 layered ceramic specimen consisted of 128 pitches of $420{\mu}m$ in width and $450{\mu}m$ in thickness were prepared by using the Ti-rich PZT compositions co-fired at $1,050^{\circ}C$. Their electrical and ultrasound pulse-echo properties were investigated and compared to the single layer specimen. The 3 layered ultrasound probe showed 1.584 V of Vp-p, which is 3.2 times higher than single layered one, implying that it would allow effectively such a portable ultrasound probe system. The result were discussed in terms of higher capacitance, lower impedance and higher dielectric coefficient of the 3 layered ultrasound probe.

Three Dimensional Electro-Fluid-Structural Interaction Simulation for Pumping Performance Evaluation of a Valveless Micropump (무밸브 마이크로 펌프의 성능평가를 위한 3차원 전기-유체-구조 상호작용 해석)

  • Pham, My;Phan, Van Phuoc;Han, Cheol-Heui;Goo, Nam-Seo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.37 no.8
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    • pp.744-750
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    • 2009
  • In this study, the pumping performance of a piezoelectric valveless micropump is simulated. The micropump, which was developed in the previous work, is composed of a four-layer lightweight piezocomposite actuator, a polydimethylsiloxane (PDMS) pump chamber, and two diffusers. The piezoelectric domain, the fluid domain and the structural domain are coupled in the three-dimensional simulation. We used ANSYS for the piezoelectric and structural domains and ANSYS CFX for the fluid domain. The effects of driven frequency on the flow rate have been investigated by simulating the flow characteristics for 10 Hz and 40 Hz driven frequencies. The flow rates with respect to driven frequencies up to 300 Hz have been calculated.