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A new paper-based microfluidic switch activated by surface acoustic wave (SAW) was presented. The switch was comprised of two folded paper microchannels and an unfolded paper microchannel. One of the folded paper microchannels was connected with the unfolded paper microchannel. Two interdigital transducers (IDTs) and two reflectors were fabricated on 128° yx-LiNbO3substrate using microelectrical technology. When an amplified RF signal was applied to the IDTs, a droplet on the piezoelectric substrate was actuated to the unfolded paper microchannel by SAW. Folded angle of a folded paper microchannel was increased and connected with the other folded paper microchannel to implement ‘on’ function of the microfluidic switch. The switch was examined using red dye solution microfluids and mixed indicating solution of 330 mmol/L Citric acidmonohydrate, 10 mmol/L N-(1-Naphthyl) ethylenediamine dihydrochloride and 50 mmol/L Sulfanilamide. The presented switch is valuable for programmable paper-based microfluidic device for multiple sample analyses. [ABSTRACT FROM AUTHOR]

Poly(vinylidene fluoride) (PVDF) has been a kind of particularly attractive piezoelectric materials for its excellent piezoelectric property. It has been proven that the piezoelectric property of PVDF can be improved by electrospinning. Recently, the technical innovations on the multiple aspects of preparing electrospun PVDF nanofibers such as collecting equipment and the pretreatment emerged in endlessly. The article introduces electrospinning briefly firstly and the second part of the paper introduces some recent research on the preparation of electrospun PVDF nanofibers. The researches about promising applications using electrospun PVDF nanofibers involve biomedicine, sensors, and energy harvesting due to its flexibility, biocompatibility, and outstanding performance. The last part of the paper reviews the typical research. [ABSTRACT FROM AUTHOR]

Energy harvesting from piezoelectric is proved to be a viable technology to source low power electronic devices. In this paper, piezoelectric energy harvester is designed such that the energy is harvested by utilizing the switching of the MOSFET in DC-DC converter, which becomes an integral part of modern industrial equipment. Energy harvesting is realized by piezoelectric and converse effect of piezoelectric material. The harvester is designed to have transmitter and receiver piezoelectric separated by metal plate, connected across the drain and source terminals of the MOSFET. The performance of the harvester is experimentally evaluated with boost converter for supercapacitor storage. [ABSTRACT FROM AUTHOR]

The paper reports on the piezoelectric performance, electromechanical coupling and related energy-harvesting figures of merit of three forms of 1–2–2 composites based on domain-engineered single crystals. The effect of the single-crystal piezoelectric properties and elastic properties of the laminar polymer matrix on the appropriate figures of merit of the composite is studied. The main active components of the studied composites are [0 0 1]-poled perovskite-type single crystals with chemical compositions: 0.92Pb(Zn1/3Nb2/3)O3–0.08PbTiO3, 0.67Pb(Mg1/3Nb2/3)O3–0.33PbTiO3 and [Lix(K1−yNay)1−x](Nb1−zTaz)O3: Mn, where x = 0.06, y = 0.1–0.3, z = 0.07–0.17, and the level of Mn doping is 0.25 mol. %. Examples of non-monotonic volume-fraction dependences of the piezoelectric properties, figures of merit and anisotropy factors are analysed. New diagrams are first built to demonstrate the volume-fraction regions where a large anisotropy of the piezoelectric coefficients d3j* and electromechanical coupling factors k3j* is achieved, and where energy-harvesting figures of merit of the composite are at least five times larger than analogous parameters of single-crystal components. The studied 1–2–2 composites are of interest as anisotropic materials with high piezoelectric sensitivity and large figures of merit which are important for sensor, energy-harvesting and related applications. [ABSTRACT FROM AUTHOR]

An adaptive energy harvesting system for high voltage piezoelectric generators is presented in this paper. Maximum power point tracking scheme is applied in the adaptive system. Low-power-consumption schemes are applied in the control system and harvesting circuit. A self-startup circuit is also applied to the system. Theoretical analysis was explored to determine optimal parameters for the harvesting system. Experiments were done to verify the theoretical analysis. The experimental results show that the harvesting system can achieve an efficiency of 17.5 ∼ 73.3% for piezoelectric generator with a peak open-circuit voltage of 6 ∼ 20 V. And the harvesting system can be self-powered from low input power as 25 μW. The average power consumption of the microcontroller can be low as 3.5 μW. [ABSTRACT FROM AUTHOR]

This paper describes the manufacture of structural composites incorporating piezoelectric fibres which are finding interest in applications such as shape-changing applications, sensors to detect mechanical strain or vibration and energy harvesting. In this paper preliminary results are presented for a simple cantilever structure consisting of piezoelectric fibres with planar electrodes that are co-cured within a carbon fibre reinforced plastic (CFRP). Processing methods to embed functional fibres are described along with characterization of the piezoelectric and mechanical properties of the resulting material. [ABSTRACT FROM AUTHOR]

The use of piezoelectric ceramics as actuators and/or sensors is prevalent. This paper is aimed to explore simple but useful equivalent circuit models of piezoelectric ceramics with the consideration of energy dissipation. Based on the electrical impedance, the equivalent circuit models of piezoelectric ceramics are investigated under unloaded and loaded conditions. The characteristics and physical meanings of the circuit models are discussed by considering the frequency range of interest. The circuit models and discussions in this paper can provide a good understanding on the behaviors of the piezoelectric ceramics when designing and analyzing the piezo-based systems and structures. [ABSTRACT FROM AUTHOR]

This paper presents a two-stage adaptive boost converter with low-voltage starter for low voltage piezoelectric energy harvester. The adaptive technique can deal with a range of input voltages from the piezoelectric generator for required output voltages. The parameters of the converter including inductance, switching frequency, duty cycles and the input/output voltage are studied for conversion efficiencies. The experiment results show that a two-stage adaptive boost converter can achieve a conversion efficiency of 84.3%∼91.3% for a piezoelectric harvester in the considered low voltage range to charge an 1.5Venergy storage device. [ABSTRACT FROM AUTHOR]

The paper focuses on the analysis of the multicaloric effect in solids. In particular, the presented approach is applicable to thin films as well. For the piezoelectric material, the multicaloric phenomenon includes two well-known effects: electro and elastocaloric; and two new ones - piezoelectocaloric and flexocaloric. These new effects are due to the temperature dependence of the piezoelectric and flexoelectric coefficients. The piezoelectric effect at medium fields is found to be comparable with the electrocaloric one and can be called a giant. The obtained results can be used for the design and optimization of new cooling devices and generators. [ABSTRACT FROM PUBLISHER]

Because of the importance of the electromagnetic interference resistance in the modern life, the electromagnetic shielding of the piezoelectric vibration acceleration sensor is analyzed in this paper. The shell of the piezoelectric vibration acceleration sensor is taken as a three-layer rectangular cavity with apertures. The shielding effectiveness of the shell irradiated by plane electromagnetic wave is modelled using transmission line theory. In the modeling process, incident angle and polarization angle of the plane electromagnetic wave are introduced, and the scattering voltage produced on the outer aperture is taken as the radiation source. The aperture is taken as the asymmetrical coplanar stripline and the rectangular cavity is taken as a rectangular waveguide with one end completely open and another end completely closed. The shielding effectiveness of the cavity is calculated using transmission line theory. Compared to the others before, this method improves the completeness of the model, computation speed, and the shielding effectiveness which supplies good reference for engineering practice. [ABSTRACT FROM AUTHOR]

The thickness vibration mode of the piezoelectric composite is the most common operation mode in transducer applications. The study on the thickness vibration characteristics plays a key role in application.In this paper, the influence of volume fraction of piezoceramic on the thickness vibration characteristics of 1-3 piezoelectric composites was investigated. Through finite element analysis and simulation, the relationship between vibration performance parameters and the ceramic volume fraction of composites was obtained. The samples with volume fraction of 0.2 ∼ 0.6 were prepared by cutting and filling and tested by Impedance Analyzer.Experimental and simulation results were matched by comparison. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the effects of a jointed beam system on the performance of a piezoelectric energy harvester. An experimental model composed of three piezoelectric plates attached to three aluminum beams was used for testing. Each aluminum beam has an additional jointed beam rotating freely. The rotating jointed beam is used to adjust the operational frequency of the piezoelectric energy harvester. This multi-beam system enables a wider operational frequency bandwidth of the energy harvester and therefore increases the energy harvesting efficiency. [ABSTRACT FROM PUBLISHER]

This paper describes the manufacture of porous polytetrafluoroethylene (PTFE) and fluoroethylenepropylene (FEP) films by pressing PTFE-FEP-PTFE films between metallic meshes to produce a porous ferroelectret material. The influence of uniaxial pressing force and processing conditions (temperature and presence of a vacuum between the polymer films) on the as-formed ferroelectret film are assessed in terms on pore (void) height, distribution of pore height and film quality. The piezoelectric d33 coefficient (charge per unit force) of polarised films is measured and related to pore height and film quality. [ABSTRACT FROM PUBLISHER]

This paper reports results on effective piezoelectric properties of advanced composites based on polydomain relaxor-ferroelectric single crystals of 0.67Pb(Mg1/3Nb2/3)O3 - 0.33PbTiO3. Two variants of the single crystal/porous polymer composite with 0-3-0 connectivity are proposed to study the role of microstructural factors in forming high piezoelectric sensitivity. The effective properties of the related 0-3 single crystal/polymer composite are predicted and considered to show ways of increasing the piezoelectric anisotropy and sensitivity. Examples of the volume-fraction and aspect-ratio dependences of the effective piezoelectric coefficients d3j*, g3j*, the hydrostatic piezoelectric coefficient gh*, and squared figures of merit d33* g33* and dh* gh* of composites are analysed to show in which ranges high piezoelectric sensitivity is attained. The presence of single-crystal polydomain inclusions in the porous 3-0 matrix promotes the large effective parameters (g33* ∼ 103 mV · m/N, gh* ∼ 103 mV · m/N, d33* g33* ∼ 10-10 Pa-1, and dh* gh* ∼ 10-10 Pa-1), and the obvious high-performance advantage of the 0-3-0 composites is discussed taking into account features of their microstructure. [ABSTRACT FROM AUTHOR]

Intrinsic double ionized lead vacancies and oxygen vacancies simultaneously exist within PZT compositions and create a defect dipole. Acceptor dopants with a valence of +3 induce extrinsic single ionized oxygen vacancies whereas donor dopants with a valence of +5 induce extrinsic single ionized lead vacancies. An electron exchange can exist between single and double ionized vacancies that it was facilitated in the case of single ionized lead vacancies. As a consequence, such a transfer occurred mainly for soft PZT and almost never for hard PZT. Based on this transfer, this paper explains the softening effect and the squeeze ignition mechanism. [ABSTRACT FROM AUTHOR]

The Piezoelectric generator for energy harvesting is usually using rectangular type unimorph or bimorph. In this paper, the characteristic of the piezoelectric generator which has a circular type bender was studied for more efficiently converting the mechanical energy to electrical energy than the rectangular type. The generator consisted of circular type vibrating plate, thin piezoelectric ceramics, stub and mass. The generator was simulated with FEM(finite element method) program as changing size of each part. When the radius of the piezoelectric ceramics and the elastic body were increased and the diameter of the vibrating plate was increased, the resonant frequency was decreased. And the output voltage was increased when the radius of the elastic body was increased. The output voltage was also affected by the distance which is the mass position from center of unimorph. The piezoelectric generator was fabricated from these simulated results. The output power was 4.3[mW] when the weight of mass was 7.2g. [ABSTRACT FROM AUTHOR]

Transducer is the most important element in an ultrasonic device because it governs the conversion of electrical energy to acoustical one and vice versa. Therefore it's very important to predict its behaviour and to determine its optimal domain of functioning. Many approaches can be used in this study. The first one is the resolution of the piezoelectric equations using numerical methods. However this approach requires powerful computing systems and it is not appropriate for each situation. The second method is based on the equivalent electrical circuit and consists of using simulation software such as PSpice, VHDL or Cadence. This method can be easily adapted for any configuration provided that we have the suitable equivalent circuit so it offers much flexibility. We propose in this paper to use PSpice in order to model a pulse echo ultrasonic system. A piezoelectric disc is used for transmitting at 2.2 MHz and receiving the reflected wave. The simulation is based on the Leach model and its parameters are deduced from the acoustical characteristics of the transducer. A transmission line is used to represent the medium of propagation considering the plan wave case. We studied the effects of the backing and the propagating medium on the ultrasound behaviour. The transient and frequency response, the sensitivity and the electrical impedance are studied too. The results of simulation are compared to some measurements performed in distilled water and paraffin oil. Results obtained fit some much with those found in literature and show the validity of the used model. [ABSTRACT FROM AUTHOR]

This paper is devoted to the analysis of effective electromechanical properties and their maxima in 0-3-type composites based on (1 - x)Pb(Mg1/3Nb2/3)O3 - xPbTiO3 single crystals. It is shown that the electromechanical interaction between the single-crystal and polymer components with the anisotropy of their piezoelectric coefficients e33(n)/|e31(n)| ≥ 5 results in relations d33* ≈ e33*s33*E, g33* ≈ h33*s33*D, and kt* ≈ k33* for the electromechanical constants. These relations hold in a wide range of volume fraction and aspect ratio of the spheroidal inclusions in the 0-3 composite. An increase in the maximum values of different effective parameters is expected by forming a system of oblate air pores in the matrix. [ABSTRACT FROM AUTHOR]

In this paper, disk-type ultrasonic motor using a combination of radial and bending vibration modes is newly designed and fabricated. The characteristics of the test motor are also measured. By means of traveling elastic wave induced at the surface of circumference of the elastic disk, a steel bar in contact with the surface of circumference of elastic disk bonded onto the piezoelectric ceramic disks is driven in both directions by changing the sine and cosine voltage inputs. The stator of the motor is composed of two sheets of piezoelectric ceramic disk to bond onto both surfaces of a elastic disk, respectively. As the results, the diameter of elastic body is increased, the resonant frequency is decreased. The resonant frequency of the stator is about 92 kHz, which is composed with piezoelectric ceramic disks of 28 mm in diameter and 2 mm in thickness, and an elastic body of 32 mm in diameter and 2 mm in thickness. A driving voltage of 20 Vpp produces 200 rpm with a torque of 1 Nm and an efficiency of about 10%. [ABSTRACT FROM AUTHOR]

Lead-free piezoelectric 0.75(Bi 1/2 Na 1/2 )TiO 3 -0.20(Bi 1/2 K 1/2 )TiO 3 -0.05BaTiO 3 ceramics(abbreviated as BNKBT-20) with addition of 0.2, 0.4, 0.6 and 0.8 wt% of CeO 2 , respectively, were prepared by a conventional mixed oxide method. The addition of CeO 2 can reduce the dissipation factor and enhance the mechanical quality factor significantly. The composition with 0.4 wt% CeO 2 has a piezoelectric d 33 constant of 129 × 10 - 12 C/N and a relatively low dissipation factor (tan δ = 1.8%) at 1 kHz which shows a 50% reduction in the dissipation factor when compared with BNKBT-20 before doping (tan δ = 3.74%). [ABSTRACT FROM AUTHOR]

This paper describes the electrical properties of the CSD-derived ferroelectric PZT thin films on the oxide electrode of LaNiO 3 (LNO), which can improve the electrical fatigue for the PZT thin film. We successfully control the orientation of the resulting LNO thin film electrode by the molecular design of the precursor solution to control the orientation of the PZT thin film with a MPB composition on the LNO. As a result, PZT/LNO thin film capacitors exhibited superior electrical properties with no fatigue, not only for remanent polarization but also for piezoelectric and dielectric properties. [ABSTRACT FROM AUTHOR]

This paper reports the first evidence of piezoelectric properties of K4LiH3(SO4) 4 KLHS crystal in the temperature range 12 K-300 K. Moreover, the anomaly in the elastic properties of this crystal observed at about 50 K by the composite oscillator bar method has been related to a proton glassy state. The elastic properties of the crystal determined by piezoelectric measurements revealed an anisotropy and dispersion in the (110) plane. [ABSTRACT FROM AUTHOR]

The paper deals with the piezoelectric coefficients measurements of PZT type piezoelectric ceramics in a wide temperature range. The single beam micro-interferometer, working inside of helium optical cryostat in the range 150-330 K was used. The original design of optical cryostat was realized for the suppression of cooling system vibrations. The piezoelectric coefficients d 33 and d 31 were obtained by laser interferometer measurements of the sample strain, induced by an applied electric field. The temperature dependences of both d 33 and d 31 were fitted by polynomial function and hydrostatic piezoelectric coefficients d h were estimated from these fitted values. The temperature dependence of the piezoelectric coefficients can be used to study extrinsic and intrinsic contributions and their temperature behaviour. For this reason it is desirable to shift the low temperature limit down to 20 K and to increase the accuracy of the piezoelectric coefficients d 33 and d 31 measurement. [ABSTRACT FROM AUTHOR]

This paper proposes and tests an impact-excited piezoelectric energy harvester, which converts human kinetic energy into electrical energy. While the impulses between the ridges and the proof mass lead the piezoelectric bimorph vibrating at its resonant frequency with decaying amplitude, sequent and reasonable impulses provide higher generating electrical energy. The research described herein highlights the effect of the impact interval/vibration period ratio on the energy conversion of the aforementioned harvester. The interval between consecutive impulses,Δti, with respect to the space distance between the two ridges,Δd, and the vibration period,T, are analyzed. The fabricated prototypes provide variousΔti/Tthat can be investigated for their effect on output performance. A series of experiments demonstrate that output power is reduced by 48% with a longer interval and by 27% with a shorter interval compared to the optimized design. [ABSTRACT FROM PUBLISHER]

Tactile is defined as a continuous sensing of variable contact forces, heat transfer, slippage, and various stimuli producing pain. The contact force and slip are the primary information measured by tactile sensor. In this paper, a detailed review of the tactile sensors for detecting contact force and slip based on polyvinylidene fluoride (PVDF) piezoelectric films is presented. When a touch and relative motion occur between the sensor and an object, the PVDF film can induce an electrical field across its boundaries. Hence, the PVDF sensors are suitable for contact force and slip detection. In addition, the PVDF has numerous advantages especially the high sensitivity, large electro-mechanical transduction frequency bandwidth, high elastic permittivity, light weight and low cost. Therefore, the tactile sensor by PVDF can be developed as a versatile tool for automation applications such as the sensor systems of robotic gripper. The review describes specific information on the definition of piezoelectricity, the principle of piezoelectric signal by PVDF film, the structural design of various PVDF-based tactile sensors, the hardware and software design of tactile sensing system, as well as some typical applications of the PVDF tactile sensors in different electromechanical devices. [ABSTRACT FROM PUBLISHER]

A linear multi-degree-of-freedom piezoelectric energy harvester has been designed in this paper. The proposed energy harvester was comprised by multi-order transmission beams and traditional single cantilever beam. As the transmission beam order increases, the resonant frequencies of this kind of harvester could be tuned and reduced efficiently. The first three modes of the three-degree-of-freedom harvester occur within the range of 0-100 Hz, reaching a fair agreement with the simulation. The operating bandwidth expands to 15 Hz, 375% of the conventional piezoelectric cantilever beam, which made this designed harvester a good candidate for energy scavenging in multi-sources and wide-frequency vibration environment. [ABSTRACT FROM AUTHOR]

This paper is devoted to piezoceramic characterization using 3D-modelling. It is applied on Navy III and Navy II elements. The influence of coupling on resonance frequencies is analysed. It is shown that velocities are independent of the element dimensions and coupling is asymmetrical because it is generated by elastic constants. Characterization is described and the determination of six elastic constants (), two piezoelectric coefficients () and permittivityis explained. Calculation needs only one element: parallelepiped or cylindrical. The error made on resonance frequencies using 1D-models is deduced and can reach 20% when certain element shapes are employed. [ABSTRACT FROM AUTHOR]

Nanosatellites are small satellites used in space missions. In order to reach the aims of the missions, special high tech equipment such as small manipulators is used in nanosatellites. In this paper the authors focus on the problem of communication between the agents of the swarm. A novel design piezoelectric manipulator driven by piezoelectric actuator is presented. The main task for the manipulator is the positioning precision of the laser beam, used for the communication between the agents. The laser beam must be deflected and positioned accurately from one nanosatellite to another. Laser scanning/deflecting accuracy and dynamic characteristics of the manipulator are investigated experimentally. [ABSTRACT FROM AUTHOR]

In this paper a bistable asymmetric laminate is manufactured and coupled to a ferroelectric material for potential energy harvesting applications. A cantilever configuration is explored and the harvester response as a function of vibration frequency, vibration level and electrical load resistance examined. The harvester is characterised at low and high vibration levels where the device exhibits either single well oscillations (at low vibration amplitude) or snap-through events (at high vibration amplitude). As the vibration levels increase and the device approaches snap-through it exhibits ‘softening’ where the peak power moves to lower frequencies with differences in power levels during up-sweep and down-sweep of frequencies. Examination of the frequency dependence of power for a range of load resistances indicates a broadening of the harvester performance at higher vibration levels and during snap-through. [ABSTRACT FROM AUTHOR]

Effect of lower ionic radii (Na and Nd) substitution in A-site on the structure, dielectric, ferroelectric and piezoelectric properties of SrBi4Ti4O15(SBT) is investigated in this paper. The samples are prepared by solid state double sintering method and sol gel method based on pechini process. Substitution of smaller ions reduced the dielectric constant and remanent polarization values. But sol gel samples showed good dielectric and ferroelectric properties. A-site substitution has resulted in improved Curie temperature and piezoelectric properties. As a result, Na and Nd modified SBT ceramics are found to be excellent high temperature piezoelectric materials. [ABSTRACT FROM PUBLISHER]

This paper presents a new mathematical model of the output power by taking the secondary piezoelectric effect of a piezoelectric-electromagnetic hybrid energy harvester into account. The numerical results show that compared with the single piezoelectric power generator, the optimized external load increases the sytem power output of the hybrid energy harvester by 13.3%. Furthermore, compared with the external load optimization, the damping parameter matching improves the peak output power of the hybrid energy harvester by 23%. Hybrid energy harvesting experiments were carried out to verify the numerical analysis. The experimental results are in accordance with the theoretical results. [ABSTRACT FROM PUBLISHER]

This paper suggests the design in rectifier and array configuration for an impact-based piezoelectric energy harvesting (PEH) system, to investigate the charging efficiency. In the design of the rectifier, it is suggested that rectifying the signal from each piezoelectric module separately generates more electrical energy and charges a capacitor faster than using a single rectifier for all modules connected in series. In the structural design, the array was designed into two conditions: impacted simultaneously and impacted sequentially with a phase difference (30°, 60°, 90°, 120°, 150° and 180°). We show that when impacted sequentially with a phase difference, this allows faster charging rates of energy harvesting. Additionally, distribution of the torque required to transform the piezoelectric modules was found to be another advantage from this condition. These results could be used in the design of more-efficiently-charging impact-based PEH system. [ABSTRACT FROM AUTHOR]

Aurivillius phase (Li,Ce) doped CaBi4Ti4O15(CBT) ceramics were prepared using the conventional solid state methods. The crystal structure and microstructure were determined by X-ray diffraction and scanning electron microscopy. It was found that the (Li,Ce) ions diffused into the A site of CBT's pseudo-perovskite structure and formed a single Aurivillius type structure. The Curie-temperature (TC) of CBT based ceramics decreased whereas the piezoelectric coefficient (d33) was improved with an increase of (Li,Ce) dopants. The detailed electrical properties for Ca0.85(LiCe)0.075Bi4Ti4O15ceramics in the high temperature region were determined using electrochemical impedance spectra. It was found that oxygen vacancies make a major contribution to both electrical conduction and dielectric relaxation. The ac conductivity was found to obey Jonscher's universal law. In addition, the physical nature of electrical conduction and dielectric relaxation was addressed in this paper. [ABSTRACT FROM AUTHOR]

In this paper scanning probe microscopy investigations of surface morphology and local ferroelectric properties of sol-gel deposited PZT thin films are presented. It is shown that the films have sufficiently low surface roughness about 2 nm and small grain size about 20 nm. Possibility of the film polarization by applying both positive and negative DC voltage between the SPM probe and the sample is demonstrated. Additionally, times of residual piezoresponse signal relaxation are measured and domain wall velocity for the PZT films is calculated. [ABSTRACT FROM AUTHOR]

The modified 1-3 piezocomposites were prepared in order to improve the stability of underwater acoustic transducers. The composite consists of 1-3 ceramic/epoxy composite and ceramic plate with series pattern. It was fabricated by dicing PZT ceramic along mutually perpendicular directions on the flat and then filling epoxy into grooves. In the paper, the cylinder transducer array made of modified 1-3 composite was fabricated. The performance of the transducer was investigated. The resonance frequency is 72 kHz when the diameter of the transducer is 85 mm. The transmitting voltage response reached 139 dB at 72 kHz, the receiving sensitivity was -212 ± 4 dB in the frequency range of 20 kHz to 60 kHz, the directivity pattern was omnidirectional in horizontal direction and with beam width of 12° in vertical direction. [ABSTRACT FROM AUTHOR]

A new testing method for hydrostatic piezoelectric constant, dh, was studied in this paper. This testing system consists of five parts, which are hydrostatic simulator, signal acquisition and processing circuits, data acquisition, serial communication interact circuit, data processing and display. Researched the method of signal acquisition for hydrostatic piezoelectric charge, designed the charge amplifier circuit, signal processing circuit as well as the data acquisition and serial communication interact circuit with microcomputer, programmed for the date acquisition and processing system software. The hydrostatic piezoelectric constant, dh, of piezoelectric ceramic samples were tested. The experimental results showed that this new testing method is available. The new testing system is characteristic of manipulation simply and low cost. [ABSTRACT FROM AUTHOR]

Energy recovery from wasted or unused power has been the topic of discussion for a long time. In recent years, industrial and academic research units have focused on harvesting energy from mechanical vibrations using piezoelectric transducers. These efforts have provided the initial research guidelines and have brought in light the problems and limitations of implementing the piezoelectric transducer. There are three major phases/steps associated with piezoelectric energy harvesting: (i) mechanical-mechanical energy transfer, including mechanical stability of the piezoelectric transducer under large stresses, and mechanical impedance matching, (ii) mechanical-electrical energy transduction, relating with the electromechanical coupling factor in the composite transducer structure, and (iii) electrical-electrical energy transfer, including electrical impedance matching, such as a DC/DC converter to accumulate the energy into a rechargeable battery. This paper deals with detailed energy flow analysis in piezoelectric energy harvesting systems with typical stiff 'Cymbals' and flexible piezoelectric transducers, in order to provide comprehensive strategies on how to improve the efficiency of the harvesting system. Energy transfer rates are practically evaluated in the above all steps. [ABSTRACT FROM AUTHOR]

The paper details the preparation of PZT-PVdF composites of 50 Vol% with 0-3 connectivity using densified and calcined reinforcement by hot press technique and the analysis of the depoling studies to know the contribution of the individual phases to the piezoelectric charge coefficient. The homogenous distribution of PZT reinforcement in the polymer matrix was confirmed by SEM studies. The composites prepared with densified PZT as reinforcement were found to exhibit higher piezoelectric coefficient when compared to the calcined one. The depoling study reveals that the d33 value in the composites prepared with densified reinforcement is contributed by the ceramic phase and for the composite with calcined reinforcement the polymer alone contributes to the d33 value. [ABSTRACT FROM AUTHOR]

The paper is focused to the nonlinear electromechanical properties of piezoelectric thin films subjected to the high electric field. The influence of the electric filed on the piezoelectric body is presented by the change of the elastic and piezoelectric modules. Experimentally, the zinc oxide (ZnO) thin film samples of (002)-orientation were prepared by RF magnetron sputtering the Pt/Ti/SiO2/Si substrates. The thin film samples were investigated under high electric field excitations and corresponding strains. The samples exhibit frequency dispersion and nonlinear piezoelectric response, i.e. the nonlinear dependence of the mechanical displacement d0 (or effective piezoelectric coefficient d33,eff) on the electric field. In the frequency range (0.1 - 1.5) kHz, the remarkable frequency dispersion of the mechanical displacement d0 was found on the ZnO samples. The characteristic nonlinearities and hysteresis are presented, using the data, measured on the PZT (60/40) (111) thin film sample. The nonlinear electromechanical properties of the ZnO thin films were investigated by original double beam laser interferometer at room temperature. The results are discussed and compared with already published data. [ABSTRACT FROM AUTHOR]

This paper discusses the requirements for piezoelectric thin film applications to radio frequency (RF) surface and bulk acoustic wave (SAW/BAW) devices. First, we survey the basic properties of RF SAW/BAW devices. We then discuss how device performances depend on the acoustic and piezoelectric properties of the piezoelectric thin films. Next, we discuss the effects of crystal grains and their boundaries within the thin films, and show how the binding strength of crystal grains affects the excitation and propagation of acoustic waves. Finally, we present basic design and characterization procedures for an SAW transversal filter employing an AlN/diamond structure. [ABSTRACT FROM AUTHOR]

Piezoelectric ceramics, constituting an active element, make a stator vibrate generating a rotational force in ultrasonic motors. In the drive of ultrasonic motors, many factors exist that can affect the resonance characteristics of piezoelectric ceramics. For example, those factors are the bonding conditions with the elastic body, the magnitude of the electric field, the normal force for the frictional drive, the emission of heat due to vibration and friction, and so on. Therefore, it is important to properly research the inclination for variation of piezoelectric ceramics in the circumstance where complex elements are involved. In this paper, we focus on the analysis of the resonance characteristics of an ultrasonic motor due to the magnitude of the input voltage and normal force. [ABSTRACT FROM AUTHOR]

This paper studies polarisation orientation effects in 1-3 composites with two piezo-active components. It is shown how the orientation of the main crystallographic axes in 0.93Pb(Zn1/3Nb2/3)O3-0.07PbTiO3 single-crystal rods and the poling direction of a polyvinylidene fluoride matrix affect the volume fraction behaviour of the piezoelectric coefficients, squared figure of merit and hydrostatic parameters of the composites. For a fixed orientation, effective parameters calculated using the matrix approach are compared with those evaluated by the finite element method. Possible property advantages concerned with orientation effects, maxima of effective parameters and high performance of these composites are analysed taking into consideration the electromechanical properties of the components. [ABSTRACT FROM AUTHOR]

This paper presents a new method for determining the permittivity profile of an inhomogeneous material. The measurement method chosen is the transmission line method in coaxial line geometry and simple is included between the two conductors of the coaxial line. The reconstruction process pass throw the resolution of a direct problem and permit therefore to shape a grind datum. The solution to the problem is then obtained by seeking in this grind datum the profile that gives back minimal errors between calculated and observed coefficient. [ABSTRACT FROM AUTHOR]

The paper deals with electromechanical properties of piezoelectric PZT (54/46) compositions near MPB, (001)-orientation, rhombohedral PZT (60/40) (111), and ZnO (002) thin films sputtered on the Pt/Ti/SiO2/Si substrates. The thin film samples were investigated under high electric excitations and corresponding strains. The samples exhibit frequency dispersion and nonlinear piezoelectric response (hysteresis), i.e. the nonlinear dependence of the mechanical displacement d0 (or effective piezoelectric coefficient d33,eff) on the electric field. I the case of ZnO samples, the remarkable decrease of the mechanical displacement d0 in the frequency range (0.1-1.5) kHz was found. These results are compared with data obtained on the PZT (60/40) (111) sample. The nonlinear electromechanical properties of the PZT and ZnO thin films were investigated using the original double beam laser interferometer at room temperature. The results are discussed and compared with the published data. [ABSTRACT FROM AUTHOR]

Relaxors have a wide variety of industrial applications because of their high permittivity and piezoelectricity around room temperature. Although the microscopic mechanism of the relaxor behavior has not been fully elucidated yet, there are some fundamental developments in the experimental studies in the last decade, which are briefly reviewed in this paper with particular reference to pioneering works of Professor Ginzburg on phase transitions in ferroelectricity. [ABSTRACT FROM AUTHOR]

Amplified Piezoelectric Actuators offer the advantage of large deformation (up to 8%) and large strokes. Because of a prestress applied to the piezo ceramics and an efficient mechanical amplifier, they can produce large strokes both in static and dynamic conditions including resonance. For these reasons, these actuators can be used for micro positioning, structure shaping, structure active damping, vibration generation, fluid control functions or energy harvesting, in various domains such as spacecraft, aircraft, instrumentation, optics, machine tools & production equipment. This paper presents these actuators, explains their properties as regard amplification and dynamic forces, and describes some applications. [ABSTRACT FROM AUTHOR]

In this paper we present potassium niobate elastic and piezoelectric constants measurements. These experiments have been performed by Brillouin spectroscopy which gives a direct access to the elastic coefficient by measuring the acoustic velocity. To avoid problems related to the angle precision on Brillouin spectroscopy, three different samples corresponding to X-cut, Y-cut and Z-cut have been used. The complete set of elastic constants is given and results are compared with those obtained previously by other authors. A discussion around the accuracy of the results is developed to explain discrepancy between previous results given in the literature. [ABSTRACT FROM AUTHOR]

This paper presents some nonlinear piezoelectric properties and strain simulation in lead zirconate-titanate Pb(ZrxTi1 - x)O3 (PZT) thin films, sputtered on the Pt/Ti/SiO2/Si substrates. The samples PZT (60/40), (111) orientation, rhombohedral phase composition, and PZT (54/46), (001) near MPB were prepared. Thicknesses of the samples under test were estimated as 1.1, 1.3 and 2.2 μ m respectively. For first characterizations, X-ray diffraction (XRD), piezoelectric hysteresis, capacitance-voltage C(V) and strain vs. temperature dependencies were carried out. The effective piezoelectric coefficient d33, eff≈ 110 pm/V was found for PZT (60/40), and d33, eff≈ 70 pm/V for PZT (54/46) at room temperature, if the biasing electric field goes slowly from the one state to opposite state by 10 mHz, using the monitoring field of the amplitude 0.09 MV/m and frequency 1 kHz. The non-linear behaviour of the PZT thin film, as the effective d33, eff vs. electric field was investigated by double beam laser interferometer and optical helium cryostat. Comparing our previously obtained data, the results are discussed. As consequences, the strain distribution in active thin PZT film area under top electrode was provided by FEM (ANSYS 8.0) and demonstrated in the contribution. Simulation of the dynamic deformation of the active thin PZT film area was presented during the conference ECAPD8. [ABSTRACT FROM AUTHOR]

The paper deals with the dynamic measurement of the hydrostatic piezoelectric coefficients of Pb(ZrxTi1 - x)O3(PZT) piezoelectric ceramics. The non-linear phenomena as the influence of a DC electric field on the hydrostatic voltage coefficient gh of a PZT sample was studied at various temperatures. Values of the coercive field were determined and compared with ones obtained from polarization vs. electric filed P(E) hysteresis loop measurements. Using the LVDT sensor, the deformation vs. electric field S(E) hysteresis loop, measured in the wide temperature range, was provided too. A noticeable influence of the temperature on coercive field values was exhibited both for hard and soft PZT ceramics (APC 841 and APC 856). [ABSTRACT FROM AUTHOR]

The paper summarizes our experiences of various electric driving of piezoelectric elements (piezoelectric membranes, actuators, piezoelectric ceramic transformers, etc.) with help of the fast digital electronic components - particularly the Field Programmable Gate Arrays (FPGA), eventually the Digital Signal Processor (DSP). These components are often used in the piezoelectric applications with the extreme rate requirements - e.g. the driving ultrasonic piezoceramic motors by Pulse-width modulation (PWM) signal or the controlled elasticity of the piezoelectric materials. [ABSTRACT FROM AUTHOR]