Electrical nonlinear-parametric high order frequency divider
Electrical nonlinear-parametric high order frequency divider
L.V. Balakin, M.D. Karasev, V.I. Medvedev
An electrical version of ahigh - order nonlinear parametric frequency divider is proposed and realized for the first time to overcome defects found in electro - mechanical nonlinear parametric frequency dividers. The divider has as its basic section a high - quality electrical oscillatory low-frequency system resembling an underexcited RC oscillatory with Wien bridge operating under rigid constraints when half the voltage period of the divided frequency is fed to it. The division ratio, relation between amplitude of the distributed oscillations and the difference between the divided oscillations in the division band, and the relation between amplitude of distributed oscillations and the pumping voltage are all experimentally studied. The division circuit may be used to perform a division with ratio m ≤ 53 in a single cascade. An equivalent circuit of our frequency divider is presented in which truncated equations for the amplitude and phase are obtained by means of the slowly varying amplitude method. The stability of the nonzero solutions of the system of truncated equations is studied. Relations between the amplitudes of the distributed low-frequency oscillations and the (a) voltage misalignment of the divided frequency; (b) the pumpumping voltage; and (c) division ratio m are theoretically computed.
Show AbstractStudy of tricritical point in triglycineselenate crystal by dynamical heat method at high pressure
Study of tricritical point in triglycineselenate crystal by dynamical heat method at high pressure
В.A. Strukov, Pоlandоv I.N., V.A.Chernenko, V.K. Novik
The temperature dependences of the heat capacity of triglycineselenate crystal are experimentally studied over a broad range of temperatures and in direct proximity to the phase transition at different pressures up to 6.5 kbar. The dependences $(∆C)^{-2}=f(T)$ are approximated by straight lines only in the range $T_{c}$-T=0,2—1,5°С. The coefficient В in the Landau expansion of free energy is independent of pressure. Processing of the results in terms of critical indices showed there was a gradual variation in the index with pressure. At a pressure of 4 kbar, it was close to one half. The results are discussed under the assumption that defects influence the phase transition in triglycineselenate. It is concluded that at p = 1 bar, the phase transition in triglycineselenate is a phase transition of the first kind close to the tricritical point.
Show AbstractThe structure of separated flow downstream from rough body
The structure of separated flow downstream from rough body
E.P. Anisimоva, A.A. Speranskaya, S.G. Shaphaev
Result s are presented of an experimental investigation of the structure of the velocity field in separated flow arising in the streamline of a semicylinder located on a smooth subjacent surface. The axis of the semicylinder is perpendicular to the incident flow, and the Reynolds number is equal to 2.1*10$^{5}$. The velocity field is studied by means of a two-component mechanotron - based anemometer. The existence of two separation zones is confirmed, with one located in front of and the other behind the semicylinder. In separated flow behind the semi-cylinder, a unique displacement layer is found; the vertical profiles of the longitudinal component of the mean velocity in the separated flow right up to the attachment zone are similar to the profile of the mean velocity in a plane turbulent displacement layer. The measured vertical profiles of the dispersion of the horizontal and vertical velocity components and the moment of correlation of the latter indicate significant spatial irregularity in the region of separated flow of the distribution of the integral characteristics of turbulence in the longitudinal direction. An analysis of the fluctuation autospectra of the velocity showed two statistically significant maxima which follow the semicylinder in the separation zone and corresponding Strouhal numbers from 0.013 to 0.018 and from 0.031 to 0,036.
Show AbstractStudy of the stability of stationary regimes of many-circuite oscillator
Study of the stability of stationary regimes of many-circuite oscillator
G.P. Minina
An oscillator with slightly nonlinear active element characteristic bound to an arbitrary linear oscillatory system is considered in the article. Stability equations and equations for determining the stationary amplitude and frequency of the self - excited oscillations of sucha system are obtained. The equations are written in a form convient for computing the stability of the steady states of real multi - circuit self - excitedo scillatory systems. As an example, stability criteria for the self - excited oscillations in a three - circuit frequency stabilization system with a large regeneration reserve in the oscillatory circuit are obtained.
Show AbstractThe spin-hamiltonian constant valuations with second order precision
The spin-hamiltonian constant valuations with second order precision
V.N. Lazukin, A.N. Terentjevskii, V.I. Danilenko
Numerical solutions of the analytic expressions of different spin Hamiltonians are obtained by the method of perturbation theory. In addition, the general form of the spin Hamiltonian matrix is diagonalized by computer. A comparison of the computed estimates obtained by general methods may be used to numerically estimate the capabilities of methods from perturbation theory as a function of the electron spin resonance spectra thin - structure constant evaluation.
Show AbstractA method of studing of lock in oscillators with resonance coupling
A method of studing of lock in oscillators with resonance coupling
G.P. Minina
A semigraphical method of treating lock in oscillators with a fractional - multiple ratio between the frequencies related by means of the resonance circuits is described. Domains of frequency synchronization, the system's frequency characteristics, and regions of in - phase and counter - phase regimes are obtained, and regions that remain stable with respect to a phase criterion are identified. The method proposed for considering mutual synchronization of oscillators may be used to obtain relatively simple analytic expressions by means of which it is possible to obtain a relation between the oscillator operation and various parameters.
Show AbstractAutomized setup «Optical Doppler anemometer—computer ES-1010» for the study of slow hydrodynamic flows in real time scale
Automized setup «Optical Doppler anemometer—computer ES-1010» for the study of slow hydrodynamic flows in real time scale
M.V. Evdokimov, A.V. Priezzhev
Experience gained in the use of the ES-1010 computer for processing the output signal of an optical Doppler anemometer in real time in study of slow stationary and fluctuating flows with velocities up to several mm/sec is described. Processing of the signals, which, in the general case, constitute nonstationary random processes, is performed by the BPF method. By means of a flexible software system, it is possible to implement information storage, processing, and output regimes in the interactive mode and to vary the regimes over broad ranges.
Show AbstractEfficiency of surface waves generation in beam-plasma systems
Efficiency of surface waves generation in beam-plasma systems
V.К. Grishin, M.F. Кanevsкii
The effectiveness of surface wave generation in the case of generation saturation is considered for the two most typical instances:(1) broad beam fanning of a plasma surface free of the magnetic field; (2) the beam fans a narrow plasma column (the beam and plasma are magnetized). The beam state is described by a nonlinear kinetic equation, and the plasma remains a linear dispersing medium. It is shown that the use of plasma fanning beams promotes marked increases in generation effective - ness.
Show AbstractOxygen effects in the NMR experiments
Oxygen effects in the NMR experiments
S.D. Varlamov, Yu.S. Konstantinov, A.M. Smirnov
NMR experiments on light irradiation of liquids containing oxygen are described. The NMR frequency shifts when a small portion of the volume of the object is illuminated are measured. The shifts are attributed to local variation of the magnetic susceptibility that arises in the course of local variation of the concentration of dissolved oxygen and local variation of the temperature in the illuminated portion of the volume of the object. A study of the relation between the longitudinal relaxation time of chloroform protons and ultraviolet light irradiation time makes it possible to estimate the lifetime of particles that react with oxygen.
Show AbstractNonlinear kinetic wave-beam equilibrium in damping systems
Nonlinear kinetic wave-beam equilibrium in damping systems
Grishin V.K., Shaposhnikova E.N.
The equilibrium state arising as a result of the development of beam instability in a damping system is studied by means of an exact solution of the nonlinear self-consistent kinetic equation for a purely harmonic wave. A number of basic system characteristics of a system in the equilibrium state, e.g., dispersion equation, efficiency of transf ormation of the beam's kinetic energy into field energy and the particle capture coefficient, are obtained.
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