• Title, Summary, Keyword: Piezoelectric

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Characterization of Nanoscale Electroactive Polymers via Piezoelectric Force Microscopy

  • Lee, Su-Bong;Ji, Seungmuk;Yeo, Jong-Souk
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.232.2-232.2
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    • 2015
  • Piezoelectric force microscopy (PFM) is a powerful method to characterize inversed piezoelectric effects directly using conductive atomic force microscopy (AFM) tips. Piezoelectric domains respond to an applied AC voltage with a characteristic strain via a contact between the tip and the surface of piezoelectric material. Electroactive piezoelectric polymers are widely investigated due to their advantages such as flexibility, light weight, and microactuation enabling various device features. Although piezoelectric polymers are promising materials for wide applications, they have the primary issue that the piezoelectric coefficient is much lower than that of piezoelectric ceramics. Researchers are studying widely to enhance the piezoelectric coefficient of the materials including nanoscale fabrication and copolymerization with some materials. In this report, nanoscale electroactive polymers are prepared by the electrospinning method that provides advantages of direct poling, scalability, and easy control. The main parameters of the electrospinning process such as distance, bias voltage, viscosity of the solution, and elasticity affects the piezoelectric coefficient and the nanoscale structures which are related to the phase of piezoelectric polymers. The characterization of such electroactive polymers are conducted using piezoelectric force microscopy (PFM). Their morphologies are characterized by field emission-scanning electron microscope (FE-SEM) and the crystallinity of the polymer is determined by X-ray diffractometer.

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ELECTROMECHANICAL ANALYSIS OF PIEZOELECTRIC STACK ACTUATOR (적층 압전 액추에이터의 전기-기계적 특성 분석)

  • Ha, Gi Hong;Lee, Soo Il
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.374-378
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    • 2014
  • The piezoelectric materials convert from mechanical energy to electrical energy. The piezoelectric materials are used in various engineering applications such as piezoelectric ultrasonic actuators. Since the piezoelectric coupling characteristics of the actuator systems should be considered at the initial design stage, it is essential to analyze the piezoelectric coupling characteristics of the ultrasonic actuators. In this study, we analyzed the electromechanical characteristics of piezoelectric stacked actuator using the equivalent circuit model with modal mass stiffness parameters. It was compared the admittance of piezoelectric stack actuators with the analytical circuit model and the finite element model. Also, the coupling coefficient of piezoelectric stack actuator was discussed according to the number of stacks of actuators.

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Design Analysis of Step-down Multilayer Piezoelectric Transformer

  • Hoonbum Shin;Hyungkeun Ahn;Han, Deuk-Young
    • Journal of Power Electronics
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    • v.3 no.2
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    • pp.139-144
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    • 2003
  • In this paper, 11 and 13 layered step-down piezoelectric transformers were fabricated and their electrical characteristics have been analyzed for AC-adapter. When the voltage is applied to the driving piezoelectric vibrator polarized in the longitudinal direction, the output voltage is generated at the generating piezoelectric vibrator polarized in the thickness direction due to the piezoelectric effects. From the piezoelectric direct and converse effects, symbolic expressions between the electric inputs and outputs of the step-down piezoelectric transformer are derived with an equivalent circuit model. With those expressions, load and frequency characteristics are discussed through the simulations. Output voltage and current from a 11-layered and a 13-layered piezoelectric transformers were measured under the different load and frequency conditions. First we measured resonant frequency from impedance curve and got equivalent impedance value of the piezoelectric transformer from admittance plot. It was shown from experiments that output voltage increase s and resonant frequency changes according to the various resistor loads. Output current decreases inversely proportional to the change of loads. Moreover, the measured output voltage and current are well matched with the simulated results obtained from the proposed equivalent circuit model. Furthermore, a new step-down piezoelectric transformer has been suggested to Increase the output power based on a simulation result having a driving piezoelectric vibrator polarized thickness direction.

A comprehensive review on the modeling of smart piezoelectric nanostructures

  • Ebrahimi, Farzad;Hosseini, S.H.S.;Singhal, Abhinav
    • Structural Engineering and Mechanics
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    • v.74 no.5
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    • pp.611-633
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    • 2020
  • In this paper, a comprehensive review of nanostructures that exhibit piezoelectric behavior on all mechanical, buckling, vibrational, thermal and electrical properties is presented. It is firstly explained vast application of materials with their piezoelectric property and also introduction of other properties. Initially, more application of material which have piezoelectric property is introduced. Zinc oxide (ZnO), boron nitride (BN) and gallium nitride (GaN) respectively, are more application of piezoelectric materials. The nonlocal elasticity theory and piezoelectric constitutive relations are demonstrated to evaluate problems and analyses. Three different approaches consisting of atomistic modeling, continuum modeling and nano-scale continuum modeling in the investigation atomistic simulation of piezoelectric nanostructures are explained. Focusing on piezoelectric behavior, investigation of analyses is performed on fields of surface and small scale effects, buckling, vibration and wave propagation. Different investigations are available in literature focusing on the synthesis, applications and mechanical behaviors of piezoelectric nanostructures. In the study of vibration behavior, researches are studied on fields of linear and nonlinear, longitudinal and transverse, free and forced vibrations. This paper is intended to provide an introduction of the development of the piezoelectric nanostructures. The key issue is a very good understanding of mechanical and electrical behaviors and characteristics of piezoelectric structures to employ in electromechanical systems.

Output Power characteristics of the Piezoelectric Transformer for LCO Backlight with Piezoelectric and Piezoelectric Properties (유전 및 압전특성에 따른 LCD Backlight용 압전 트랜스포머의 출력전력특성)

  • 민석규;류주현;정회승;홍재일;윤현상;손은영
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.852-856
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    • 2000
  • In this paper, we investigated the output power, step-up ratio and efficiency properties of piezoelectric transformer with dielectric and piezoelectric characteristics of manufactured ceramics. The piezoelectric transformers with $2.0$\times$10$\times$48[$mm^3$] size were fabricated and its electrical properties were measured. When output power of 6W was constantly maintained, T2 piezoelectric transformer showed the minimum temperature rise of $9(^{\circ}C)$ at $150(K\Omega)$ load resistance. However, T1 piezoelecric transformer showed the temperature rise of $7.2(^{\circ}C)$ at $200(K\Omega)$ load resistance. The 6[w] CCFL (Cold Cathode Fluorescent Lamp) was successfully driven by T1 and T2 piezoelectric transformer but, its temperature rise $\Delta$T[$^{\circ}C)$] was generated more than $20(^{\circ}C)$. It is concluded that we have to design the piezoelectric transformers so that its output impedance correspond to the load impeadance, including any stray capacitance.

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Micro Pattern Control of Metal Printing by Piezoelectric Print-head (압전 프린트 헤드에 의한 금속프린팅의 미세패턴제어)

  • Yoon, Shin-Yong;Choi, Geun-Soo;Baek, Soo-Hyun;Chang, Hong-Soon;Seo, Sang-Hyun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.24 no.2
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    • pp.147-151
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    • 2011
  • We were analyzed the piezoelectric characteristic for electronics printing to inkjet printing system. These applications were possible use to Actuator, MEMS, FPCB, RFID, Solar cell and LCD color filter etc. Piezoelectric print head is firing from ink droplet control consideration ink viscosity properties. At this time, micro pattern for PCB metal printing was possible by droplet control of piezoelectric driving. These driving characteristics are variable voltage pulse waveform. We are used the piezoelectric analysis software of Finite Element Method (FEM), Piezoelectric design parameters are acquired from piezoelectric analysis, and measurement of piezoelectric. It designed for piezoelectric head to possible electric print pattern of inkjet printing system. For this validity we were established through in comparison with simulation and measurement. Designed piezoelectric specification obtained voltage 98V, firing frequency 10 kHz, resolution 360dpi, drop volume 20pl, nozzle number 256, and nozzle pitch 0.33 mm.

Electrical Characteristics of the High Power Piezoelectric transformer Using PSN-PZT system ceramics (PSN-PZT계 세라믹스를 이용한 고출력 압전 트랜스포머의 전기적 특성)

  • 이용우;류주현;윤광희;정회승;서성재;김종선
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.13 no.4
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    • pp.286-293
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    • 2000
  • In this paper we investigated the structural dielectric and piezoelectric properties of 0.03Pb(Sb$\_$1/2//Nb$\_$1/2/)-0.97Pb(Zr$\_$0.495//Ti$\_$0.505/)O$_3$+0.5 wt% excess PbO + wt% MnO(X=0, 0.1, 0.3, 0.5, 0.7) ceramics to develop the high-power piezoelectric transformer. The piezoelectric transformers with dimension of 27.5$\times$27.5$\times$2.5[mm$^3$]were fabricated and their electrical properties were measured. Maxima of piezoelectric properties such as electro-mechanical coupling factor of 0.534 and mechanical quality factor of 1487 were obtained for the PSN-PZT with 0.3wt% MnO. voltage step-up ratios of piezoelectric transformers at 500[Ω]and no load were 0.78, 12.82, respectively. The maximum efficiency of piezoelectric transformer was 98.6% at 800[Ω]. While the 14W fluorescent lamp were driven by the piezoelectric transformer for more than 20[min], increment of temperature in the piezoelectric transformer was 7[$\^{C}$].

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A Comparison Study of Output Performance of Organic-Inorganic Piezoelectric Nanocomposite Made of Piezoelectric/Non-piezoelectric Polymers and BaTiO3 Nanoparticles (압전 및 비압전 폴리머와 BaTiO3 나노입자로 제조된 유-무기 압전 나노복합체의 발전성능 비교연구)

  • Hyeon, Dong Yeol;Park, Kwi-Il
    • Journal of Korean Powder Metallurgy Institute
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    • v.26 no.2
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    • pp.119-125
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    • 2019
  • Piezoelectric energy harvesting technology is attracting attention, as it can be used to convert more accessible mechanical energy resources to periodic electricity. Recent developments in the field of piezoelectric energy harvesters (PEHs) are associated with nanocomposites made from inorganic piezoelectric nanomaterials and organic elastomers. Here, we used the $BaTiO_3$ nanoparticles and piezoelectric poly(vinylidene fluoride) (PVDF) polymeric matrix to fabricate the nanocomposites-based PEH to improve the output performance of PEHs. The piezoelectric nanocomposite is produced by dispersing the inorganic piezo-ceramic nanoparticles inside an organic piezo-polymer and subsequently spin-coat it onto a metal plate. The fabricated organic-inorganic piezoelectric nanocomposite-based PEH harvested the output voltage of ~1.5 V and current signals of ~90 nA under repeated mechanical pushings: these values are compared to those of energy devices made from non-piezoelectric polydimethylsiloxane (PDMS) elastomers and supported by a multiphysics simulation software.

Electrical Charateristics of Step-down Piezoelectric Transformer

  • Shin Hoonbum;Ahn HyungKeun;Han Deuk-Young
    • Proceedings of the KIPE Conference
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    • pp.47-51
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    • 2001
  • In this paper, we have explained electrical characteristics of a step-down Rosen type piezoelectric transformer for AC-adapter. When the electric voltage is applied to the driving piezoelectric vibrator polarized in the longitudinal direction, then output voltage is generated at the generating piezoelectric vibrator polarized in the thickness direction due to the piezoelectric effects. From the piezoelectric direct and converse effects, symbolic expressions between the electric inputs and outputs of the step-down piezoelectric transformer have derived with an equivalent circuit model. With the symbolic expressions, load and frequency characteristics have discussed through simulation. Output voltage and current from a 11-layered and a 13-layered piezoelectric transformers were measured under the various conditions of loads and frequencies. First we measured resonant frequency from impedance curve and got equivalent impedance value of the piezoelectric transformer from admittance plot. It was shown from experiments that output voltage has increased and resonant frequency has changed according to various resistor loads. Output current has decreased inversely proportional to changing of loads. Moreover, the measured values of output voltage and current are well agreed with the simulated values of the proposed equivalent circuit model.

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Measurement of In-plane Piezoelectric Charge Constant of Electro-Active Paper (Electro-Active Paper의 면내압전상수 측정)

  • Li, Yuanxie;Yun, Gyu-Young;Kim, Heung-Soo;Kim, Jae-Hwan
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.943-946
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    • 2007
  • In-plane piezoelectric charge constant of Electro-Active paper (EAPap) was investigated based on direct and converse piezoelectric effects. EAPap samples were made with cellulose film with very thin gold electrode coated on both sides of the film. To characterize direct piezoelectricity of EAPap, induced charge was measured when mechanical stress was applied to EAPap. In-plane piezoelectric charge constant was extracted from the relation between induced charge and applied in-plane normal stress. To investigate converse piezoelectricity, induced in-plane strain was measured when electric field was applied to EAPap. Piezoelectric charge constant was also extracted from the relation of induced in-plane strain and applied electric field. Piezoelectric charge constants obtained from direct and converse piezoelectricity are 31 pC/N and 178 x 10-12m/V for 45 degree sample, respectively. Measured piezoelectric charge constants of EAPap provide promising potential as a piezoelectric material.

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