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Significance of Micro and Nano PZT Particles on Dielectric and Piezoelectric Properties of PZT-PVDF Composites
摘要： PZT-PVDF composites were prepared using different particle size of PZT and a hot press apparatus has been used for making samples. The structural and compositional analysis of the composite sample was done by using Scanning Electron Microscope (SEM) and Energy Dispersive Analysis of X-rays (EDAX) respectively. The grain size of the ball milled PZT powder was analyzed using powder X-Ray Diffraction (XRD). The samples were poled at a fixed temperature for about an hour under different poling fields. The dielectric constant (εr) and the piezoelectric properties like piezoelectric strain coefficient (d33) and voltage coefficient (g33) of composite have been analyzed.
关键词： composite,ferroelectric materials,dielectric constant,strain coefficient,voltage coefficient,particle size,lead zirconate titanate
更新于2025-09-23 15:22:29
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Graphene-SiO <sub/>2</sub> Interaction from Composites to Doping
摘要： An overview of the interaction between monolayer graphene and SiO2 dielectric substrate is reported focusing on the effect this latter has on doping and strain induced by thermal treatments in controlled atmosphere. The disentanglement of strain and doping is highlighted and the comparison with another dielectric substrate of Al2O3 evidences the critical role that the substrate has in the electronic properties of graphene. The reported results pave the way for microelectronic devices based on graphene on dielectrics and for Fermi level tuning in composites of graphene and nanoparticles.
关键词： doping,graphene,silica,strain
更新于2025-09-23 15:22:29
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Enhancement of monolayer SnSe light absorption by strain engineering: A DFT calculation
摘要： Strain effects on the electronic and optical properties of monolayer SnSe is studied by APW + lo method in DFT framework. The applied strains cause direct-indirect transition of SnSe band gap which is mainly constructed by s/p hybridization. The armchair εac and zigzag εzz reduce the unstrained band gap of 1.05 eV down to 0 eV at 12% compression, but at 12% tension, the band gap decreases to 0.726–0.804 eV. The band gap always increases under biaxial strain εb at at 12% compression to 12% tension. We observe an enhancement of real ε1(ω) and imaginary ε2(ω) parts of dielectric function by 14% ? 30% of magnitude, wider peak distribution to infrared and ultra-violet regions, and appearance of new peaks in the ε1(ω) and ε2(ω) spectrums. As a consequence, the light absorption α(ω) is significantly enhanced in the ultra-violet region and the absorption even starts at lower energy at infrared region.
关键词： Strain,Optical properties,Electronic band structure,First-principles,Monolayer SnSe
更新于2025-09-23 15:22:29
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Energy harvesting properties of the functionally graded flexoelectric microbeam energy harvesters
摘要： Flexoelectricity may be an excellent candidate for piezoelectricity in micro and nano scaled energy harvesters due to its strong size dependency. In this paper, a size dependent analytical model of the cantilever-based functionally graded flexoelectric energy harvesters is developed. The Hamilton’s principle is used to derive the governing equations. By means of the Galerkin’s method, the approximated closed-form solutions of electrical output and energy conversion efficiency are obtained. For the functionally graded flexoelectric energy harvester, the effective flexoelectric response is controlled by not only the flexocoupling coefficient but also its first derivative. Numerical results of a 3μm-thick Polyvinylidene Fluoride/ Strontium Titanate composed functionally graded flexoelectric energy harvester demonstrate that when the volume fraction exponent varies from zero to infinity, the optimal working frequency gradually reduces from 41407Hz to 7761Hz and the optimal load resistance gradually increases from 0.99MΩ to 83.91 MΩ. Meanwhile, shrinking the thickness from 3μm to 0.3μm will highly increase the normalized power density and the energy conversion efficiency about one and two orders, respectively. Moreover, when the strain gradient elastic coefficient becomes larger, the natural frequency will increase while the corresponding maximum electrical output will decrease.
关键词： Functionally graded materials,Flexoelectric effect,Cantilever beam,Strain gradient elastic effect,Energy harvesters
更新于2025-09-23 15:22:29
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Ultra-low hysteresis electric field-induced strain with high electrostrictive coefficient in lead-free Ba(Zr Ti1-)O3 ferroelectrics
摘要： From the application point of view, high electric field-induced strain with ultra-low hysteresis or hysteresis-free characteristic is highly desired in high-precision displacement actuators. In this work, lead-free Ba(ZrxTi1-x)O3 (BZT) ferroelectrics with x in the range between 0.02 and 0.1 were fabricated by a conventional solid state reaction method. The structural evolution and electrical properties were investigated systematically with an emphasis on electrostrictive effect. As x increases from 0.02 to 0.1, the crystal lattice parameters (a and c axes) increase while the tetragonality (c/a-1) goes down. In addition, the Curie temperature (TC) of BZT decreases gradually, while the temperatures corresponding to tetragonal-to-orthorhombic (T-O) and orthorhombic-to-rhombohedral (O-R) phase transitions increase. Ultra-low hysteresis (<8%) and high electric field-induced strains (>0.15% at 60 kV/cm) are observed in all studied compositions. Most importantly, a high longitudinal electrostrictive coefficient Q33 (0.0453 m4/C2) was also identified in x=0.1 composition. This work not only reports high electric field-induced strains with ultra-low hysteresis and high Q33 in lead-free BZT ferroelectrics, but also indicates a potential application for BZT ceramics in high-precision displacement actuators.
关键词： Electrostriction,Ferroelectric,Lead-free,Electric field induced strain,BZT
更新于2025-09-23 15:22:29
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Piezoelectric properties of a near strain-free lead zirconate titanate thin films deposited on a Si substrate
摘要： Chemical solution deposition (CSD)-derived near strain-free lead zirconate titanate (PZT) thin films on a Si substrate were prepared by designing a buffer layer structure. Strain-free PZT thin films with different compositions ranging from Zr/Ti = 50/50 to 58/42 were obtained to demonstrate lattice strain effects on piezoelectric properties. Results show that a near strain-free condition was attained with a SrRuO3 (SRO: 160 nm)/(La0.5,Sr0.5)CoO3 (LSCO: 90 nm)/LaNiO3 (LNO: 120 nm)/stacking structure, even on a Si substrate. The highest effective d33 value of the near strain-free PZT thin film was observed at 53/47 composition, which is the same as bulk materials, although the highest effective d33 value was obtained from 58/42 composition under the compressive lattice strain condition.
关键词： Chemical solution deposition,Piezoelectricity,Thin films,Multilayer structure,Lattice strain,Sol-gel preparation
更新于2025-09-23 15:22:29
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Synthesis Graphene Based Sensor for strain data and its characterization
摘要： Graphene material with fine structure is used to fabricate for the different types of sensors. Graphene are mostly 2D structure bounded by sp2 carbon atoms in a honeycomb lattice parameter prented. Strain sensors are immense interest over the past years, which is used to deduct the change in the human bodies. It applicable in various field such as chemical, mechanical, electrical and electronic sensor. Graphene based strain sensors fabricated in a form of stretchable rubber by the way of stamping technique. Under this process mechanical properties of the synthesized graphene materials was systamatically discussed and also investigated the x-ray diffraction, surface manufacturing studies, raman spectroscopy and I-V characteristics studies. Finally, strain sensor for human body was measured by connecting with the with glove and the strain was measured corresponding with resistance values. After stretching glove, the strain value become the original position. The strain change based on the resistivity during the exercise the period.
关键词： Graphene,XRD,Strain sensor,I-V charecteristics
更新于2025-09-23 15:22:29
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Strain Monitoring on PHC Pipe Piles Based on Fiber Bragg Grating Sensors
摘要： Fiber Bragg grating (FBG) sensors emerged as a relatively new strain-sensing technology for civil engineering applications. This study presents a field test to assess the feasibility of FBG sensors in monitoring the strain profile of prestressed high-strength concrete (PHC) pipe piles during installation. Two open-ended PHC pipe piles were instrumented with FBG sensors and then driven into the ground using a hydraulic jacking machine. To measure the strain profile along the test piles, nine FBG sensors were arranged in a single optical fiber and then mounted on one pile at the opposite side to monitor the strain at different levels as a function of wavelength shift. The procedure for installing the FBG sensors along the PHC pipe piles is introduced first. Next, the distribution of the axial forces and average side shear stresses that were evaluated from the strain measurements of the FBG sensors are discussed. The field test results indicate that the FBG sensor system was suitable for monitoring the strain state of PHC pipe piles during installation. The axial forces and side shear stresses along the test piles were influenced significantly by the penetration depth and the local soil resistance.
关键词： Fiber Bragg grating (FBG) technology,Jacking method,Strain monitoring,Prestressed high-strength concrete (PHC) pipe pile
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE 15th International Conference on Group IV Photonics (GFP) - Cancun (2018.8.29-2018.8.31)] 2018 IEEE 15th International Conference on Group IV Photonics (GFP) - Enhanced Tensile Strain in Ge Epitaxitial Layers Grown on Si-on-Quartz Wafers
摘要： Ge epitaxial layers grown on Si-on-“quartz” wafers reveal an enhanced in-plane tensile strain of 0.36±0.03%, which is 2–3 times larger than those grown on ordinary Si-on-insulator wafers. The enhancement is derived from an increased thermal expansion mismatch.
关键词： Si-on-quartz wafer,Ge,tensile strain
更新于2025-09-23 15:22:29
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High Strain Sensitivity Temperature Sensor Based on a Secondary Modulated Tapered Long Period Fiber Grating
摘要： A novel sensor structure has been proposed and experimentally investigated for simultaneous strain and temperature measurement. The structure is fabricated by weak power modulation of CO2 laser exposure on tapered long period fiber grating (LPFG). Compared with the transmission spectrum of the tapered LPFG, two peaks appear in the transmission spectrum of the novel structure. These resonance peaks exhibit different sensitivity responses; thus, simultaneous measurement of strain and temperature is realized by monitoring the wavelength shift of the two peaks. Experiment results indicate that strain sensitivities of the two peaks are 1.82 pm/με and 8.17 pm/με, and temperature sensitivities are 47.9 pm/°C and 65 pm/°C, respectively.
关键词： strain,simultaneous measurement,temperature,Taper,CO2 Laser
更新于2025-09-23 15:22:29