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The studies of the temperature dependence of electrical and physical features of various kinds of solidly mounted resonators (SMR) are presented. The findings help to improve the accuracy of model by adjusting the piezoelectric and electrode thin film thickness.

The envelope impedance (EI) concept was used to develop a systematic and simple approach for studying the conditions for stability of piezoelectric transformers (PT) based ballasts for cold cathode fluorescent lamps (CCFL) systems and the implications of the thermal operating conditions on such systems. The envelope analysis of the CCFL, which was verified experimentally, revealed that the magnitude of the negative EI decreases with temperature. This might cause the system to become unstable at low temperatures due to the fact that the loop gain of the PT-CCFL system encircled the (- 1, 0) point in the Nyquist plane. In such cases, the PT-CCFL system may enter a quasi-stable oscillatory operation mode in which the current is AM modulated by a low frequency parasitic signal. This phenomenon is analyzed and explained by considering the temperature effect on the EI of the CCFL. The results of this work provide an insight into the stability issue of the PT-CCFL system, and could help in finding remedies to the instability. Index Terms--Cold cathode fluorescent lamp (CCFL), envelope impedance (EI), piezoelectric transformer (PT).

Mass sensitivity of thickness-twist modes in a rectangular piezoelectric plate of 6-mm crystals or polarized ceramics was obtained. It was seen that for the inertial effect the first-order approximation of frequency shifted is accurate for thin mass layers and for long waves or thin plates the inertial effect was larger than the stiffness effect.

An approximate nonlinear analysis of a simple plate thickness-shear mode transformer near resonance from the three-dimensional equations of nonlinear electroelasticity is presented. It was observed that on one side of the resonant frequency the input--output relation became nonlinear and on the other side there was a jump in the voltage output experience.

The propagation of thickness-twist waves through a joint between two semi-infinite piezoelectric plates of various crystals of 6-mm symmetry with piezoelectric coupling is discussed. The solution showed the cutoff of certain waves and the presence of localized electromechanical fields near the joint.

Vibration effect that was generated by using bimorph actuators instead of using stack-type piezoelectric actuators is described. In order to obtain desired motion and to enhance the output performance proper modes associated with ultrasonic levels of the resonant frequency were selected.

The exact antiplane also referred to as shear-electric horizontal (SH) modes for face shear and thickness-twist vibrations of polarized ceramics of a rectangular piezoelectric plate were studied. Maximum optimization was observed in the transforming ration, input admittance and efficiency functions of the load.

An adaptive backstepping control scheme that was proposed in order to obtain precise trajectory tracking of a piezoactuctor-driven stage is discussed. Improvements in the tracking performance, steady-state error and robustness to disturbance are achieved with the help of the control approach to trajectory tracking of the piezoactuator-driven stages.

The effect of the application of alternating current (ac) fields of diminishing amplitude on depolarization of a sol-gel-derived niobium-doped lead zirconate titanate film is studied by evaluating the piezoelectric coefficient. It is found that depending on the initial polarization and the direction of the ac fields, the film is gradually depolarized with fields of successively smaller amplitude and that there is interaction between the microdomains which causes very high switching fields in some of them.

A method is presented for measuring the spring constant and modeling the deflection of piezoelectric devices. The model gives an estimation of the required input voltage or electrical power for piezoelectric devices of any application.

A study is conducted to analyze the effects of a parallel resistor on the electrical transient characteristics, including maximum voltages, time constants, energy losses and average powers of a Rosen-type piezoelectric transformer (PT). The results show that the additional resistor is of a great help, as it leads to high energy losses and increased average powers in the PT and the oscilloscope due to the increased parallel resistance.

The time evolution of the transition energy of a set of InGaN quantum-well structures following pulsed optical excitation is discussed. The calculations used to quantify the degree of screening at typical threshold carrier densities are projected.

An innovative technique that produces a significant improvement of the power capability of piezoelectric transformers is presented. This technique consists of a nonlinear processing of the piezoelectric transformer output voltage, which results in strong enhancement when applied to the piezoelectric transformer.

The defect and band edge related signals in the optical spectra for Ga-doped ZnO thin film were described using a piezoelectric photothermal (PPT) spectroscopy. The PPT peak of 2.5eV was observed for undoped ZnO grown under a low oxygen flow rate (OFR) while Ga-doped samples did not show any peak, indicating that Ga doping inhibits the generation of the oxygen vacancies.

The influence of electrode arrangement on the resonant characteristics of piezoceramic disks is examined using three experimental techniques. The dependence of electrode design on the vibration frequencies and mode shapes is discussed.

The design, fabrication and characterization of a new type of standing wave piezoelectric ultrasonic motor are presented. The laser Doppler vibration measurements confirmed the vibration mode estimated by finite element modeling (FEM).

A fine grain, relaxor-based piezoelectric ceramic has been investigated, which was fabricated using the columbite precursor method. The measurement results show that this fine-grain investigated ceramic is a very good material for making ultrasonic array transducers.

A torsional microtransducer for high power applications is developed. Using this design described, high-power torsional transducer with diameters of 5mm and below are now possible.

Lithotriptors, electrically prestraining the material in compression is proposed to increase the pressure at the surface of ultrasonic shock head. This idea is supported by the fact that PZT rods are more fragile in extension mode than in compression mode.

An analytic method is presented to study the flexural vibration of rectangular transducers consisting of piezoelectric ceramic thin plates based on the equivalent elastic method and coupled vibration theory. This method can be used in the resonance frequency analysis of vibrating systems in coupled vibration.

A piezoelectric transformer operating at the thickness shear vibration mode with dual or triple output is proposed in this study. It is seen that there is a driving frequency range in which the load resistance of one output has little effect on the voltage gain of another output.

The effects of external elastic and electric fields of the near-coercive strength on the piezoelectric response of lead titanate (PbTi[O.sub.3]) monodomain single crystals are investigated. The Landau-Ginzburg-Devonshire theory has shown that there is a qualitative difference in the way in which the proximity of 90 [degree] and 180 [degree] polarization switching affects the piezoelectric response and its anisotropy.

The all-electrical indentation shear modulus and elastic modulus measurement technique are investigated by using piezoelectric cantilever sensors with a tip for potential in vivo applications. A model tissue consisting of modeling clay embedded on gelatin has shown that the indentation compression and indentation shear tests have provided two-dimensional elastic and shear moduli maps or images.

The water vapor sensitivity of polymer coated piezoelectric substrates is analyzed with regard to different types and crystallographic orientations of the substrates. The study of the surface acoustic waves (SAW) propagation along polymer coated single crystal and polycrystalline piezoelectric substrates is used as an experimental tool for thin film characterization.

A method is developed to prepare two-phase nanoparticulate composites consisting of a magnetostrictive core and piezoelectric shell in an attempt to improve the mechanical coupling between the phases and thereby enhance the magnetoelectric effect. It was seen that the highest magnetoelectric effect occurred in the composition of 50 wt. % ferrite sintered at 1200 degrees Celsius.