Piezoelectric Coefficient
Mostrando 1-12 de 12 artigos, teses e dissertações.
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1. Local piezo-response for lead-free Ba0.9Ca0.1Ti0.9Zr0.1O3 electro-ceramic by switching spectroscopy
The purpose of this work is to determine the effective piezoelectric coefficient (d33) and the macro ferroelectric hysteresis behavior for the Ba0.9Ca0.1Ti0.9Zr0.1O3 (BCZT). The sample was prepared by the modified Pechini method and it was sintered at 1250 ºC for 5 h. The refinements of X-ray diffraction (XRD) patterns obtained by the Rietveld method sugges
Mat. Res.. Publicado em: 11/01/2018
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2. Desenvolvimento de imunossensores piezelétrico e eletroquímico para detecção de amostras de interesse agronômico e de saúde / Desenvolvimento de imunossensores piezelétrico e eletroquímico para detecção de amostras de interesse agronômico e de saúde / Development of piezoelectric and electrochemical immunosensors to detect samples of agronomic interest and public health / Development of piezoelectric and electrochemical immunosensors to detect samples of agronomic interest and public health
This work shows development of immunosensors for agronomic interest and public heath. The first was a piezoeletric immunosensor to detect a cysteine peptidase, a potencial biomarker for Xanthomonas citri subsp. citri that cause a citrus Canker. Another was electrochemical immunosensor based on gold nanoparticles as a label and magnetic beads as capture phase
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 23/07/2012
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3. Parametric analysis of effective material properties of thickness-shear piezoelectric macro-fibre composites
A previous study on the characterization of effective material properties of a d15 thickness-shear piezoelectric Macro-Fibre Composite (MFC) made of seven layers (Kapton, Acrylic, Electrode, Piezoceramic Fibre and Epoxy Composite, Electrode, Acrylic, Kapton) using a finite element homogenization method has shown that the packaging reduces significantly the s
J. Braz. Soc. Mech. Sci. & Eng.. Publicado em: 2012
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4. Sensor piezelétrico baseado na tecnologia dos eletretos termo-formados: aprimoramentos dos processos de produção / Piezoelectric sensor based on electrets thermoforming technology: improvements on the production processes
This work describes two improvements on the production of piezoelectric sensors, which are based on thermo-formed electrets technology. These sensors which were previously prepared by fusing and molding two Teflon FEP films into bubbles structures in a hot-press system, presented piezoelectric coefficients over 300 pC/N after properly electrical charging. Ho
Publicado em: 2010
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5. Propriedades estruturais de L-arginina.HCl.H2O pura e dopada com Fe usando difraÃÃo de raios-X de N-feixes. / Structural properties of pure and Fe-doped L-arginine.HCl.H2O using diffraction of N-beam X-ray.
Neste trabalho usamos a varredura Renninger (VR) da difraÃÃo mÃltipla de raios-X (DMRX) na determinaÃÃo dos coeficientes piezelÃtricos do cristal de L-arginina.HCl.H2O dopado com :Fe (L-AHCl. H2O:Fe) atravÃs das distorÃÃes produzidas na cÃlula unitÃria do cristal sob a aÃÃo de um campo elÃtrico. A vantagem desta tÃcnica à a possibilidade de o
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 21/09/2007
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6. Projeto, construÃÃo e caracterizaÃÃo de um amortecedor ativo controlado por atuador piezoelÃtrico / Design, construction and characterization controlled by Piezoelectric Actuato
This thesis presents the design methodology, the construction of a prototype and the experimental validation of an active vibration damper witch is controlled by a piezoelectric actuator. The proposed device has two flexible metallic bellows connected to a rigid reservoir filled with a viscous fluid. When one of the bellows is connected to a vibrating struct
Publicado em: 2007
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7. Termo eletretos de teflon FEP como transdutores piezelétricos / Thermo electrets of teflon FEP as piezoelectric transducers
Os termo eletretos piezelétricos de teflon FEP apresentam-se como elementos que podem competir em preço e funcionalidade com os transdutores atuais. Quando carregados impulsivamente, as folhas de teflon FEP retêm cargas elétricas superficiais por um período longo, superior a 500 anos. Excitados mecanicamente, resultam em um alto nível de sinal elétric
Publicado em: 2006
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8. Temperature coefficient of piezoelectric constants in Pb(Mg1/3 Nb2/3)O3 - PbTiO3 ceramics
In this work, the thermal stability of piezoelectric constants of PMN-PT ceramics in the tetragonal and rhombohedral phases were investigated in a wide range of temperatures. The results showed that the tetragonal PMN-PT presented higher thermal stability and, consequently, the temperature coefficients for the piezoelectric constants were approximately zero.
Materials Research. Publicado em: 2004-06
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9. Study of pyroelectric activity of PZT/PVDF-HFP composite
Flexible, free-standing piezo and pyroelectric composite with 0 to 3 connectivity was made up from Lead Zirconate Titanate (PZT) powder and poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) copolymer. The pyroelectric and the piezoelectric longitudinal (d33) coefficients were measured. A 50/50 vol.% PZT/PVDF-HFP composite resulted in piezo and pyroele
Materials Research. Publicado em: 2003-12
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10. Study of apodization of piezoeletric ceramics / Estudo da apodização de ceramicas piezoeletricas
The objective of this work was to optimize the process of apodization of piezoelectric ceramics disks, looking for the better relation between the insulating oil bath temperature and the smaIlest period of time through which the poling field must be applied. The apodization of the piezoelectric ceramic is performed to reduce the diffraction in the acoustic f
Publicado em: 2003
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11. Surface acoustic wave propagation in Y- and Z-cut 0.67PbMgNbO3–0.33PbTiO3 single crystals
Surface acoustic wave (SAW) propogation in Y-cut and Z-cut relaxor-based 0.67Pb(Mg1∕3Nb2∕3)O3–0.33PbTiO3 (PMN-33%PT) ferroelectric single crystals poled along [001]c cubic direction has been analyzed theoretically. Characteristic curves were obtained for the phase velocity, electromechanical coupling coefficient and PFA of SAW in Y-cut and Z-cut PMN-33
American Institute of Physics.
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12. Importance of mitral subvalvular apparatus in terms of cardiac energetics and systolic mechanics in the ejecting canine heart.
To assess the importance of the intact mitral subvalvular apparatus for left ventricular (LV) energetics, data from nine open-chest ejecting canine hearts were analyzed using piezoelectric crystals to measure LV volume. After mitral valve replacement with preservation of all chordae tendineae, baseline LV function was assessed during transient caval occlusio