RESEARCH OF THE RESONANCE PROPERTIES OF HELMHOLTZ RESONATORS

The object of research. Process of oscillation of the Helmholtz resonators. Investigated problem. Differences between some formulas for the calculation of the resonant frequency of the Helmholtz resonator and the most accurate of them were established. The effect of acoustic design on the Helmholtz resonator frequency value and influence of the attached air mass between the neck of the Helmholtz resonator and free field were investigated. The main scientific results. As a result of a numerical experiment, analytical ratios were obtained that allow obtaining the most accurate results. One of them is the most optimal for calculating the resonator resonant frequency in a free field, and in this case, less than 1 % inaccuracy level can be achieved, given that r/R<0.25. Other one allows to achieve the same low inaccuracy level for a resonator located in an acoustically rigid shield, given that r/R<0.25. Research has shown that the location of the resonator in an acoustically rigid shield leads to significant changes in natural resonance frequency value. The area of practical use of the research results. The detailed research of previously unexplored properties of resonators will make it possible to improve the algorithms for the development of metamaterials, to discover additional parameters with which it is possible to control the characteristics of the metamaterial. Scope of the innovative technological product. Such resonators are used as the basic elements in metamaterials, as structural elements of the sound-absorbing panels, in acoustic mufflers.

METHOD FOR CALCULATING THE RELIABILITY OF QUARTZ RESONATORS

In the process of developing a thermocompensated quartz generator, it was necessary to calculate the reliability indicators of such an important element of the circuit as a quartz resonator for a failure-free period of 15 000 hours. The main parameter that can be used to evaluate the reliability of the quartz resonator is the stability of the nominal oscillation frequency. It is the stability of the nominal frequency of the resonator that formed the basis of the new developed technique. The method includes rules for constructing a probabilistic and statistical model of the dependence of the resonator frequency change on the test time. The article describes the work done on the accelerated evaluation of the reliability of piezoelectric resonators RK563 on the basis of probabilistic and statistical modeling of the behavior of the frequency from the test time. The method of mathematical modeling is based on the results of incomplete tests for a period of 30…50 % of the set value of the minimum operating time.

Impulse Conditioner for Verification (Calibration) of Digital Electronic Stopwatch-Timers

New upgraded device for digital electronic stopwatch-timers calibration has been developed and researched. Real value of quartz resonator frequency has been measured. New device provides the stopwatch-timers calibration of various models for any frequency spectrum. The device enables to shorten the time for calibration and to reduce the calibration uncertainty. Control procedure for main digital stopwatch-timers characteristics has been described. The procedure doesn’t contain any handmade operations depended on operator reaction. Already there are no necessity to use any mechanic device for start/stop of stopwatch-timers.

Quantum Mechanical Engine for the Quantum Rabi Model

We consider a purely mechanical quantum cycle comprised of adiabatic and isoenergetic processes. In the latter, the system interacts with an energy bath keeping constant the expectation value of the Hamiltonian. In this work, we study the performance of the quantum cycle for a system described by the quantum Rabi model for the case of controlling the coupling strength parameter, the resonator frequency, and the two-level system frequency. For the cases of controlling either the coupling strength parameter or the resonator frequency, we find that it is possible to closely approach to maximal unit efficiency when the parameter is sufficiently increased in the first adiabatic stage. In addition, for the first two cases the maximal work extracted is obtained at parameter values corresponding to high efficiency, which constitutes an improvement over current proposals of this cycle.

Isoenergetic Cycle for the Quantum Rabi Model

The isoenergetic cycle is a purely mechanical cycle comprised of adiabatic and isoenergetic processes. In the latter the system interacts with an energy bath keeping constant the expectation value of the Hamiltonian. This cycle has been mostly studied in systems consisting of particles confined in a power-law trap. In this work we study the performance of the isoenergetic cycle for a system described by the quantum Rabi model for the case of controlling the coupling strength parameter, the resonator frequency and the two-level system frequency. For the cases of controlling either the coupling strength parameter or the resonator frequency, we find that it is possible to closely approach to maximal unit efficiency when the parameter is sufficiently increased in the first adiabatic stage. In addition, for the first two cases the maximal work extracted is obtained at parameter values corresponding to high efficiency which constitutes an improvement over current proposals of this cycle.