Piezoelectric Crystal Research Articles

Application of Odd Harmonic Resonances of a Single Crystal to Generation and Reception of Superharmonic Waves for Sensitive Monitoring of Heat-Treated Materials.

In nonlinear ultrasonic testing, the quadratic and more recently cubic nonlinearity parameters are frequently measured as a quantitative indicator of damaged material state. Application of higher-order harmonics can improve the sensitivity of detection and monitoring for damages and microstructures due to their higher values of nonlinearity parameters. The excitation and reception of higher-order harmonics, so-called superharmonics, which use the third to fifth harmonics arising from nonlinear wave propagation, is not sufficiently investigated and applied. The purpose of this communication is to develop a highly sensitive superharmonic nondestructive technique that efficiently generates and receives third- and fifth-order harmonics using the odd harmonic resonances of a single piezoelectric crystal. The method focuses on the measurement of fifth harmonic generation and reception, and the calculation of the relative quintic nonlinearity parameter (δ'). The method also addresses the issue of source nonlinearity that may be contained in the measured fifth harmonic amplitude. The measurement results of δ' for a series of precipitation heat-treated samples clearly show a much better sensitivity than the results of the cubic nonlinearity parameter (γ'). The proposed method enables a highly sensitive and true pulse-echo mode nonlinear ultrasound testing.

Macro- and microstructure of lead perovskite ternary piezoelectric single crystals after direct current and alternating current poling

Macro- and microstructure of lead perovskite ternary piezoelectric single crystals after direct current and alternating current poling

Non-invasive pressure-volume analysis by 3-dimensional echocardiography: a novel method for left ventricular stroke work estimation

Abstract Funding Acknowledgements Type of funding sources: Public hospital(s). Main funding source(s): Institute for Surgical Research, Oslo University Hospital. Introduction Left ventricular pressure-volume analysis is a powerful method to quantify left ventricular function. A major limitation of its clinical utility, however, is the need for invasive pressure and volume measurements. We hypothesized that accurate non-invasive left ventricular (LV) stroke work analysis is feasible by combining continuous 3-dimensional (3D) echocardiographic LV volume measurements with non-invasive LV pressure curve estimation. Purpose To investigate if LV stroke work can be estimated non-invasively by combining 3D echocardiographic volume measurements with non-invasive pressure curve estimation. Methods In 21 open-chest anesthetized canines, piezoelectric crystals were placed in the LV subendocardium for volume measurements and a micromanometer catheter was placed in the LV cavity for pressure measurements. Echocardiography was performed directly on the heart to acquire 3D LV volumes and timings of mitral and aortic valve events. The estimated LV pressure curve was obtained by adjusting the cardiac phases of an LV reference pressure curve to these valve events and adjusting its amplitude to measured peak LV pressure. Stroke work was calculated as the area under the pressure-volume curve from mitral valve closure to mitral valve opening. Non-invasively estimated and invasively measured stroke work were compared. Recordings were done during baseline, aortic constriction, dobutamine infusion and after induction of left bundle branch block by ablation. Results Panel A in the Figure illustrates non-invasive (left) and invasive (right) pressure-volume loops from a representative experiment. Baseline and the different interventions are colour-coded allowing visual comparison of the similar non-invasive and invasive stroke work. Panel B shows the pooled data from all experiments. There was a strong correlation (r=0.98, p<0.0001) and good agreement between the non-invasive and invasive stroke work. Furthermore, the non-invasive method captured similar changes in stroke work during interventions as compared to the invasive method (Panel C). Conclusions Non-invasive pressure-volume analysis by combining 3D echocardiography and estimated pressure for stroke work evaluation, is feasible and accurate.

Introduction to Point-of-Care Ultrasonography

Medical ultrasonography was first used as a diagnostic tool in 1942 by Theodore Karl Dussik to visualize brain structures. Use of ultrasonography broadened to the field of obstetrics in the 1950s and has since expanded to many other medical special-ties owing to ease of use, reproducibility, low cost, and lack of radiation. Advancements in ultrasonography technology have allowed clinicians to perform procedures with greater accuracy and to characterize tissue better than ever before. Piezoelectric crystals used to produce ultrasound waves have been replaced by silicon chips; artificial intelligence can be used to mitigate user variability; and more portable ultrasound probes are available for use with mobile devices. Ultrasonography requires training to be used appropriately, and patient and family education are crucial when performing an examination. Although some data are available regarding the amount of training needed for users to reach proficiency, this topic remains controversial and no standard currently exists.

Giant Electrostrain in Lead-Free Textured Piezoceramics by Defect Dipole Design.

By converting electrical signal into mechanical displacement, piezoelectric actuators are widely used in many applications due to their precise displacement, fast response, and small size. The unipolar electrostrain values larger than 1% reported so far are from lead-based single crystals or ceramics, which brings environmental concerns. Herein, a giant unipolar electrostrain of 1.6% with good fatigue resistance and low hysteresis in Sr/Nb-doped Bi0.5 (Na0.82 K0.18 )0.5 TiO3 lead-free textured piezoceramics by defect dipole design is reported, which is comparable to or even higher than state-of-the-art lead-based piezoelectric single crystals. The engineered defect dipoles in ergodic relaxor ferroelectrics can introduce a large internal bias field along the poling direction, where the 〈111〉-oriented defect dipoles with large polarizability aligning along the 〈111〉-oriented spontaneous polarizations of the electric-field-induced ferroelectric phase greatly benefit the reversible phase-transition process of the 〈00l〉-textured ceramic. In-depth microstructural studies reveal that the greatly enhanced electrostrain is realized by the synergistic contributions from the reversible electric-field-induced phase transition, grain orientation engineering, and most importantly, defect dipole engineering. The present research provides a general strategy for the design of piezoceramics with high electrostrain, which is expected to be promising alternative to lead-based piezoelectric actuators.

Electro-thermal actuation in percolative ferroelectric polymer nanocomposites.

The interconversion between electrical and mechanical energies is pivotal to ferroelectrics to enable their applications in transducers, actuators and sensors. Ferroelectric polymers exhibit a giant electric-field-induced strain (>4.0%), markedly exceeding the actuation strain (≤1.7%) of piezoelectric ceramics and crystals. However, their normalized elastic energy densities remain orders of magnitude smaller than those of piezoelectric ceramics and crystals, severely limiting their practical applications in soft actuators. Here we report the use of electro-thermally induced ferroelectric phase transition in percolative ferroelectric polymer nanocomposites to achieve high strain performance in electric-field-driven actuation materials. We demonstrate a strain of over 8% and an output mechanical energy density of 11.3 J cm-3 at an electric field of 40 MV m-1 in the composite, outperforming the benchmark relaxor single-crystal ferroelectrics. This approach overcomes the trade-off between mechanical modulus and electro-strains in conventional piezoelectric polymer composites and opens up an avenue for high-performance ferroelectric actuators.

Ultrahigh‐Temperature Piezoelectric Crystal YbBa3(PO4)3 for Vibration Sensing Application

AbstractHigh‐temperature vibration sensors are of great importance for accurate monitoring of dynamic mechanical conditions in automotive, aerospace and energy‐generation‐related systems. Currently, piezoelectric crystals with ultrahigh operational temperature and good piezoelectric performance for high‐temperature sensing applications are attracting considerable attention. Herein, a novel piezoelectric crystal YbBa3(PO4)3 with cubic symmetry and a high melting point of ≈1850 °C is explored, and grown by using the Czochralski method. The temperature‐dependent behaviors of electro‐elastic constants and electrical resistivity are investigated ranging from 25 to 800 °C, where the dielectric loss of the YbBa3(PO4)3 crystal is found to be ≈15% at 800 °C. In addition, an optimal crystal cut with a pure thickness shear vibration mode is designed. The optimal crystal cut presents a good piezoelectric activity ( = 12.6 pC N−1) as well as good temperature stability. Furthermore, a high‐temperature accelerometer with shear piezoelectric mode is designed and fabricated using the YbBa3(PO4)3 crystal, and the sensing performance at elevated temperature are evaluated. The average sensitivity is found to be 1.16 pC g−1, with a small temperature deviation (≈7.7%), exhibiting a good temperature stability. All these results indicate that YbBa3(PO4)3 piezoelectric crystal is a promising candidate for high‐temperature piezoelectric sensing applications.

THE USE OF ULTRASOUND TOMOGRAPHY TO IMPROVE ULTRASOUND CONTROL EFFICIENCY

To ensure safe and reliable operation of pipeline systems, it is necessary to regularly carry out work on technical diagnostics. Ultrasonic inspection is one of the most common methods for pipeline technical condition determining. It has many advantages over other control methods among which there can be distinguished accessibility, the absence of additional requirements for equipping the object under examination, the absence of an impact on the object of control itself, and safety. But ultrasonic inspection also has disadvantages some of which can be eliminated by using an individual piezo elements of multi-element transducer instead of simple single-element transducers.
 The method of pipeline wall thickness determining using piezo elements of a multi-element transducer, as well as searching for and identifying the type and size of the defect, is known as ultrasonic tomography.
 This paper presents the main features of the transducers used in ultrasonic tomography, possibilities of ultrasonic tomography when it is used in field pipeline diagnostics. The advantages of using the method of ultrasonic tomography in comparison with conventional ultrasonic control are considered.

High-Sensitivity Chitin Nanofiber-Coated Series Piezoelectric Quartz Crystal Humidity Sensors

This paper fabricated a high-performance chitin nanofibers-coated interdigital electrode-piezoelectric quartz crystal (IDE-PQC) humidity sensor. Firstly, this paper investigated the influence of each Butterworth-Van Dyke equivalent parameter of the piezoelectric quartz crystal on the resonance characteristics of the IDE-PQC humidity sensor. Then, the results of MATLAB calculations revealed that the resonant frequency of the IDE-PQC humidity sensor changes larger (i.e., higher sensitivity) by increasing the PQC electrode area and decreasing the quartz wafer thickness. Next, the theoretical result was proved using advanced design system (ADS) simulation. Finally, the moisture-sensitive performances of IDE-PQC humidity sensors with different electrode areas and quartz wafer thicknesses were tested using chitin nanofibers as the moisture-sensitive material. The experimental results showed that the IDE-PQC humidity sensor with a larger electrode area and thinner quartz wafer thickness has higher sensitivity. This paper provides a new solution for building a high-performance series piezoelectric quartz crystal sensor.

Extended topological interface modes with tunable frequency in the piezoelectric phononic crystal

Acoustic metamaterials have provided a versatile platform to explore more degrees of freedom for tunable topological wave manipulation. Recently, extended topological interface modes (ETIMs) with heterostructure have been proposed to extend the spatial degree of freedom. However, the absence of frequency tunability still restricts the application of the wave transports of ETIMs. Here, we propose a one-dimensional piezoelectric topological phononic crystal (PTPC) with electrically tunable working frequency by introducing external capacitor circuit. With the bandgap frequency actively controlled by appropriately tuning the capacitances, we construct the heterostructured PTPCs possessing high-energy-capacity ETIMs with electrically tunable working frequency range and bandwidth. This work paves the way to wide engineering applications on acoustic sensing enhancement, nondestructive testing, energy harvesting, information processing, and reconfigurable topological wave transports.

Integration of Footstep Power Generation with Energy Storage Systems for Sustainable Power Supply

Abstract: This design is generating electricity in a non traditional expressway in this type we exercise piezo sequel to induce electricity the pressure is applied on piezo component which creates the electricity that sequel exercised in step authority generation, in this we created a mechanical arrangement for them to turned on bedded system. The at mega 8/168/328 microcontroller is exercised control the tackle outfit detention on colorful outfit it can numerous tackle outfit through the series law and detention. the bedded system is interface with TV( liquid demitasse exposition) and the step count is reflected down in the TV the system main function and regulator is Arduino uno Ac and Dc regulator unidirectional regulator, 12v,1.3 Amp supereminent acid battery and an inverter is assumed 12 volts ac is converted to ac force the loads are actuated utilizing 230 volts Ac we're utilizing rechargeable battery to authority the compass and AURDINO is interface between the liquid demitasse flash 16X2 exposition. Though it will not meet the demand of electricity but as a matter of fact if we're suitable to design a authority generating bottom that can produce 100W on precisely 12 way, also for 120 way we can produce 1000 Watt and if we install similar type of 100 bottoms with this system also it can produce 1MegaWatt. Which itself is an acquirement to make it significant.

Second gradient continuum model for anisotropic elastic and piezoelectric structures calibrated based on phonon dispersion relations

In this paper, we present a variant of the second gradient continuum model that allows description of the spatial dispersion effects of high-frequency waves in anisotropic crystals. The considered model takes into account the strain and inertia gradient effects and the classical electro-mechanical coupling. The simplified constitutive equations of the model contain seven and four length scale parameters for piezoelectric hexagonal crystals and elastic cubic crystals, respectively. It is shown that all except one length scale parameter can be identified based on the fitting of the continuum model to the lattice dynamics calculations for the dispersion relations of the bulk acoustic phonons. Examples of the identification are presented for hexagonal piezoelectric ZnO and AlN and for cubic diamond and Si crystals. Using a calibrated model, we then obtain the dispersion relations for the high-frequency Bleustein–Gulyaev wave in piezoelectric crystals and for the shear horizontal surface wave in elastic crystals. The last one is predicted by the gradient models only for the high frequencies, while at low frequencies this wave degenerates to the bulk shear wave. Examples of calculations are also provided for the Rayleigh wave propagating through the homogeneous piezoelectric half-space and layered ZnO(AlN)/diamond/Si structures. It is shown that this kind of surface wave can be used to identify the last unknown length scale parameter of the model.

Real‐Time Quantification of Cell Mechanics and Functions by Double Resonator Piezoelectric Cytometry – Theory and Study of Cellular Adhesion of HUVECs

AbstractCell mechanics is closely associated with cellular structure and function. However, the inability to measure both cellular force and viscoelasticity of statistically significant number of cells noninvasively remains a challenge for quantitative characterizations of various cellular functions and practical applications. Here a double resonator piezoelectric cytometry (DRPC), using AT and BT cut quartz crystals of the same frequency and surface morphology is developed to simultaneously quantify the cells‐generated forces (ΔS) and viscoelastic moduli (G′, G″) of a population of isolated single cells or cells with different degrees of cell‐cell interactions in a non‐invasive and real time manner. DRPC captures the dynamic mechanical parameters ΔS and G′, G″ during the adhesions of human umbilical vein endothelial cells (HUVECs) under different ligand densities of adhesion molecules fibronectin or Arg‐Gly‐Asp (RGD) modified on the gold surfaces of 9 MHz AT and BT cut quartz crystals, and different seeding densities of HUVECs. It is found that both the ligand density and cell seeding density affect the magnitudes of ΔS and G′, G″ and their correlations are revealed for the first time by DRPC. The validity of DRPC is further verified by mechanical changes of the cells in response to treatments with cytoskeleton regulators.

Preparation and acoustic properties of high-temperature acoustic emission sensor based on La3Ga5SiO14 crystal

With the rapid development of modern industries, the high-temperature piezoelectric sensors that can work in extreme environments are in great demand. In this work, langasite (La3Ga5SiO[Formula: see text], LGS), as a high-temperature piezoelectric crystal with stable electro-elastic performance, is used as core element, and air and porous Al2O3 are selected as backing layers respectively to prepare two kinds of high-temperature acoustic emission (AE) sensors. The detection sensitivities at 25-500[Formula: see text]C are analyzed by the ball falling test and Hsu–Nielsen experiment. Under the condition of 25–500[Formula: see text]C, the received amplitude signals by both sensors are maintained above 90 dB stimulated by the ZrO2 ceramic ball dropping. In the Hsu–Nielsen experiment, as the temperature rising from 25[Formula: see text]C to 500[Formula: see text]C, the signal amplitude of sensor with air backing layer decays from 447 mV to 365 mV, while the signal amplitude varies from 270 mV to 203 mV for the sensor with porous Al2O3 backing layer. Significantly, compared with the bandwidth of the air-backing sensor (37–183 kHz), the sensor with porous Al2O3 backing layer broadens bandwidth to 28–273 kHz. These results show that both these AE sensors have strong and stable response ability to AE signals at high-temperature of 500[Formula: see text]C. Therefore, piezoelectric AE sensor based on LGS has great potential application in the field of high-temperature structural health monitoring.

A High-Temperature Accelerometer with Excellent Performance Based on the Improved Graphene Aerogel.

A high-temperature accelerometer plays an important role for ensuring normal operation of equipment in aerospace, such as monitoring and identifying abnormal vibrations of aircraft engines. Phase transitions of piezoelectric crystals, mechanical failure and current leakage of piezoresistive/capacitive materials are the prominent inherent limitations of present high-temperature accelerometers working continuously above 973 K. With the rapid development of aerospace, it is a great challenge to develop a new type of vibration sensor to meet the crucial demands at high temperature. Here we report a high-temperature accelerometer working with a contact resistance mechanism. Based on the improved graphene aerogel (GA) prepared by a modulated treatment process, the accelerometer can operate continuously and stably at 1073 K and intermittently at 1273 K. The developed sensor is lightweight (sensitive element <5 mg) and has high sensitivity (an order of magnitude higher than MEMS accelerometers) and wide frequency response range (up to 5 kHz at 1073 K) with marked stability, repeatability and low nonlinearity error (<1%). These merits are attributed to the excellent and stable mechanical properties of the improved GA in the range of 299-1073 K. The accelerometer could be a promising candidate for high-temperature vibration sensing in space stations, planetary rovers and others.

Inverse piezoelectric all-fiber voltage sensor based on tapered fiber

The all-fiber voltage sensor is difficult for application because of its complex structure, difficult signal demodulation, and sensitivity to the environment. In this paper, a wavelength modulated all-fiber voltage sensor with a simple structure is designed and proposed using straight tapered single-mode fiber and stacked piezoelectric crystal as a voltage sensing unit. The simulation analysis of its performance shows that it can realize the voltage measurement of 0 kV ∼ 10.41 kV, and the accuracy can reach 0.2%. Additionally, the tapered fiber has good strain sensitivity and temperature insensitivity, and its sensitivity is up to 0.03206 nm/με with low bending loss.

Study of Static Flexural Strength Anisotropy of Yttrium Calcium Oxyborate Crystals

As a promising optical and piezoelectric crystal, yttrium calcium oxyborate (YCOB) has been criticized for its easy fracture during both the cooling and machining processes. Herein, in order to evaluate the mechanical energy (G) required for crack propagation on one crystal plane, we measured the bending strength of the YCOB samples with different orientations via employing a three-point bending test. The surface topography of the polished sample was measured, and the average surface roughness is limited to 10 nm. Fracture surfaces were also observed and analyzed. The results showed that the bending strengths of Y-cut and Z-cut samples were higher than other cut directions in the XZ principal plane, showing obvious anisotropy. It can be found that the cleavage planes (2¯01) and (101) were always observed in fractured samples in multiple directions in the XZ principal plane. The contribution of the cleavage planes (2¯01) and (101) to the fracture of the specimens was discussed in detail by the theorem of energy minimum. Finally, based on the obtained scanning electron microscopy results, we propose the mechanism for crack advance in YCOB crystals. A perfectly brittle crack in a crystal prefers cleavage planes with low surface energy. It is believed that these findings may provide fresh ideas to overcome the cleavage fracture of larger size YCOB crystals.

Controlling the breakup of spiralling jets: results from experiments, nonlinear simulations and linear stability analysis

We experimentally and numerically study the dynamics of a liquid jet issued from a rotating orifice, whose breakup is regulated by a vibrating piezo element. The helical trajectory of the spiralling jet yields fictitious forces varying along the jet whose longitudinal projections stretch and thin the jet, affecting the growth of perturbations. We show that by quantifying these fictitious forces, one can estimate the jet intact length and size distribution of drops formed at jet breakup. The presence of the locally varying fictitious forces may render high-frequency perturbations, that would otherwise be stable in the abscence of stretching, unstable, as observed similarly in the case of straight jets stretching under gravity. The perturbation amplitude then dictates how strong the perturbation is coupled to the jet compared with random noise that is inherently present in any experimental set-up. In the present study we exploit the slenderness of the jet to separate the calculation of the base flow and the growth of perturbations. The fictitious forces calculated from the base flow trajectory are then used in a nonlinear slender-jet model, which treats the spiralling jet as a quasi-straight jet with locally varying body forces. We show both experimentally and numerically that jet breakup characteristics (e.g. intact length and drop size distribution) can be controlled by finite-amplitude perturbations created by mechanically induced pressure modulations. Finally, we revisit the integrated net gain approach developed for straight jets under gravity and we provide simple analogous relations for spiralling jets.

Coexistence of two hole phases in high-quality p−GaAs/AlGaAs in the vicinity of Landau-level filling factors ν=1 and ν=(1/3)

We focused on the transverse AC magnetoconductance of a high-mobility $p$-GaAs/AlGaAs quantum well $(p=1.2\ifmmode\times\else\texttimes\fi{}{10}^{11}{\mathrm{cm}}^{\ensuremath{-}2})$ in the vicinity of two values of the Landau-level filling factor $\ensuremath{\nu}$: $\ensuremath{\nu}=1$ (integer quantum Hall effect) and $\ensuremath{\nu}=1/3$ (fractional quantum Hall effect). The complex transverse AC conductance ${\ensuremath{\sigma}}_{xx}^{\mathrm{AC}}(\ensuremath{\omega})$ was found from simultaneous measurements of attenuation and velocity of surface acoustic waves propagating along the interface between a piezoelectric crystal and the two-dimensional hole system under investigation. We analyzed both the real and imaginary parts of the hole conductance and compared the similarities and differences between the results for filling factor 1 and filling factor 1/3. Both to the left and to the right of these values maxima of a specific shape, ``wings,'' arose in the $\ensuremath{\sigma}(\ensuremath{\nu})$ dependences at those two $\ensuremath{\nu}$. Analysis of the results of our acoustic measurements at different temperatures and surface acoustic wave frequencies allowed us to attribute these wings to the formation of collective localized states, namely, the domains of a pinned Wigner crystal, i.e., a Wigner solid. While the Wigner solid has been observed in 2D hole systems previously, we were able to detect it at the highest hole density and, therefore, the lowest hole-hole interaction reported.

A Holistic Solution to Icing by Acoustic Waves: De‐Icing, Active Anti‐Icing, Sensing with Piezoelectric Crystals, and Synergy with Thin Film Passive Anti‐Icing Solutions

AbstractIcing has become a hot topic both in academia and in the industry given its implications in transport, wind turbines, photovoltaics, and telecommunications. Recently proposed de‐icing solutions involving the propagation of acoustic waves (AWs) at suitable substrates may open the path for a sustainable alternative to standard de‐icing or anti‐icing procedures. Herein, the fundamental interactions are unraveled that contribute to the de‐icing and/or hinder the icing on AW‐activated substrates. The response toward icing of a reliable model system consisting of a piezoelectric plate activated by extended electrodes is characterized at a laboratory scale and in an icing wind tunnel under realistic conditions. Experiments show that surface modification with anti‐icing functionalities provides a synergistic response when activated with AWs. A thoughtful analysis of the resonance frequency dependence on experimental variables such as temperature, ice formation, or wind velocity demonstrates the application of AW devices for real‐time monitoring of icing processes.