Piezoelectric transformer with parallel oscillatiry circuit

Piezoelectric transducers are widely used in electroacoustics, hydroacoustics, in ultrasound, medical, measurement technique, in scanning probe nanomicroscopes, piezoengines and in other fields of science and technology. To create transducers with necessary characteristics the technology of additional elements can be used

Piezoelectric transformer with parallel oscillatiry circuit

Piezoelectric transducers are widely used in electroacoustics, hydroacoustics, in ultrasound, medical, measurement technique, in scanning probe nanomicroscopes, piezoengines and in other fields of science and technology. To create transducers with necessary characteristics the technology of additional elements can be used

Piezoelectronic transducers sound based on bamorph elements

Piezoelectric transducers are widely used in underwater acoustics, electroacoustics in ultrasound, medical and measuring equipment. The methodsof improvement of descriptions of piezoelectric acoustic transducers are considered in this work

Electro-Acoustic System with Piezoelectric Sensor

Piezoelectric transducers are widely used in electro-acoustic, hydroacoustic, ultrasonic, medical and measuring techniques, security and control systems. One of the main characteristics of the piezoelectric transducers is operation frequency band. Despite the fact that it is used to be expanded, narrowband piezoelectric transducers also can be used. In particular, the fields of application of piezoelectric transducers are narrowband alarm systems, for example, glass breakage detectors [1]

Ginzburg-Landau theory for the time-dependent phase field in a two-dimensional d-wave superconductor

We derive a finite temperature time-dependent effective theory for the phase $\theta$ of the pairing field, which is appropriate for a 2D conducting electron system with non-retarded d-wave attraction. As for s-wave pairing the effective action contains terms with Landau damping, but their structure appears to be different from the s-wave case due to the fact that the Landau damping is determined by the quasiparticle group velocity $v_g$, which for the d-wave pairing does not have the same direction as the non-interacting Fermi velocity $v_F$. We show that for the d-wave pairing the Landau terms have a linear low temperature dependence and in contrast to the s-wave case are important for all finite temperatures.Comment: 4 pages, LaTeX; paper presented at New^3SC-3, Honolulu, Hawaii, USA, 2001. To be published in Physica

Piezoelectric Transducers in the Schemes of Bandpass and Bandstop Electrical Filters

Piezoelectric transducers are widely used in electroacoustics, hydroacoustics, measuring technology, nondestructive control, piezomotors, scanners of nanomicroscopes, other fields of science and techniques

Effect of next-to-nearest neighbor hopping on electronic properties of graphene

In the tight-binding approximation, we take into account the next-to-nearest neighbor hopping in graphene that leads to nonrelativistic-like corrections in its low energy spectrum. The electronic density of states in a magnetic field is found and the fan diagram is plotted, which interpolates between those for the relativistic and nonrelativistic limiting cases. It is shown that the Berry phase for the system under consideration coincides exactly with its value for the relativistic system

Quantum oscillations as the tool for study of new functional materials (Review Article)

We present an overview of our recent results on quantum magnetic oscillations in new functional materials. We begin with the Lifshitz and Kosevich approach for quasi-2D layered materials and obtain general formulas for the oscillatory parts of the grand thermodynamic potential and magnetization. Then we consider the oscillations of the Nernst–Ettingshausen coefficient which consists of thermal and magnetization parts. The difference between normal and Dirac carriers is also discussed. To conclude we consider a model for multilayer graphene which allows to calculate exactly the Berry phase which remains undetermined in the Lifshitz–Kosevich approach. The magnetic oscillations of the density of states and capacitance for different number of the carbon layers are described

Crossover from BCS to Composite Boson (Local Pair) Superconductivity in Quasi-2D systems

The crossover from cooperative Cooper pairing to independent bound state (composite bosons) formation and condensation in quasi-2D systems is studied. It is shown that at low carrier density the critical superconducting temperature is equal to the temperature of Bose-condensation of ideal quasi-2D Bose-gas with heavy dynamical mass, meanwhile at high densities the BCS result remains valid. The evident nonmonotoneous behaviour of the critical temperature as function of the coupling constant (the energy of the two particle bound state) is a qualitative difference of quasi-2D crossover from 3D one.Comment: 9 pages, LaTeX, no figures. (The latest version which appeared in the journal

Quantum Phase Fluctuations Responsible for Pseudogap

The effect of ordering field phase fluctuations on the normal and superconducting properties of a simple 2D model with a local four-fermion attraction is studied. Neglecting the coupling between the spin and charge degrees of freedom an analytical expression has been obtained for the fermion spectral function as a single integral over a simple function. From this we show that, as the temperature increases through the 2D critical temperature and a nontrivial damping for a phase correlator develops, quantum fluctuations fill the gap in the quasiparticle spectrum. Simultaneously the quasiparticle peaks broaden significantly above the critical temperature, resembling the observed pseudogap behavior in high-T_c superconductors.Comment: 5 pages, ReVTeX, 1 EPS figure; final version to appear in Physica