The theory of stimulated Raman scattering in a dispersive medium is extended to the case of arbitrary intensity of multimode pumping. The effect of dispersion on the stimulated Raman scattering increment is investigated. An analytic solution of truncated equations with allowance for boundary conditions is obtained for an arbitrary number of modes.
Show AbstractThe isomeric ratios in reactions $^{102}$Pd($p,n$)$^{102mg}$Ag, $^{104}$Pd($p,n$)$^{104mg}$Ag, $^{105}$Pd($p,n$)$^{105mg}$Ag are measured. The isomeric ratios for $^{105mg}$Ag were also obtained in reactions $^{103}$Rh ($α,2n$). For $^{105mg}$Ag the isomeric ratios were calculated on the basis of the statistical theory within the framework of the Fermi - gas, independent pairing of particles and superconductor models. For the spin cutoff parameter σ we obtained the values: 3,3±O,4($^{102mg}$Ag); 3,5±0,5($^{104mg}$Ag) и 4,0±0,5($^{105mg}$Ag). For $^{105mg}$Ag we obtained best agreement between the analytic and experimental values of isomeric ratios in the independent particle pairing model at density parametera $α =(А/8)$ MeV$^{-1}$, and in the superconductor model at $α =(А/6)$ МэВ$^{-1}$. The energy of excitation dependence of isomeric ratios confirms the value of spin (equal to two) for isomers $^{102mg}$Ag and $^{104mg}$Ag, previously established from decay models.
Show AbstractThe distribution of the rms deviations of vertical velocity compoents of flow and solids at different solid densities over the flow depth is examined. The intensity of fluctuations of vertical components of particle velocities decreases with increasing solids concentration.
Show AbstractThe paper describes a device making it possible to i n vestigate irreversible magnetic properties of rocks and minerals in variable magnetic fields up to 600 oersted over a frequency range from 50 Hz to 20 kHz. The residual magnetization is measured by a three-magnet astatic magnetometer with electronic feedback, which makes it possible to automate the measurements and to use a digital recorder. The magnetometer systems makes it possible to monitor the asymmetry of a variable magnetic field and the magnetization of a specimen by this field. Investigations performed with this device showed that the magnitude and stability of the partial ideal residual magnetization of rock specimens depends in a certain manner on the frequency. These effects are attributed to relaxation, induced by the diffusion magnetic aftereffect. The fact that the stability of the ideal residual magnetization is a function of both the temperature and frequency confirms the above causality.
Show AbstractWe investigated the magnetic susceptibility and thermal expansion of alloys of chromium with 1.4l atomic % of Co, chromium with 1.4l atomic % of Co plus 0.77 atomic % of V , and chromium with 0.34 atomic % of Fe plus 0.78, 1.08 and 1.63 atomic % of V over the 77 to 400°K temperature range. The fraction of magnetic susceptibility Δχ, due to addition of V , Fe and Co, is identified. Above the Neel temperature the behavior of Δχ(Т) obeys the Curie-Weiss law in all cases. Analysis of results shows that at low concentrations, atoms of V have a local magnetic moment ~ 1μ$_{{B}}$ in the Cr matrix.
Show AbstractA system of electrodes, making it possible to obtain homogeneous crossed electric fields in a limited space is described. Results of theoretical analysis of the structure of fields by the method of conformal transformations are presented.
Show AbstractThe instrumental limits of detectivity of dilatometric, semiconductor and superconducting bolometers are determined. It is shown that even at temperatures of the order of 4°K the Instrumental limits of dilatometric and superconducting bolometers may be lower than the potential limit, resulting from fluctuations in heat transfer between the heatsensing element and its surrounding medium. The instrumental limit of detectivity of semiconductor bolometers at low temperatures is higher than the potential. The level of noise temperature of amplifiers, allowing attaining the potential detectivity is determined.
Show AbstractThe problem examines analytically the question of synchronization of a distributed self-oscillatory system by a small applied force, using as an illustration the synchronization of the striation frequency by modulation of the discharge current. An analytic expression of the dependence of the bandwidth of stration synchronization on the modulation amplitude of the discharge current, and making it possible to refine the form of dispersion parameters of the strations in the self excitation domain is obtained.
Show AbstractThe specific nature of calibration fields of discrete Abelian groups of symmetries, i.e., as fields with zero strength whose sources are topological features of coordinate space, is demonstrated.
Show AbstractThe method for reconstructing a function on the basis of its moment, developed by Spencer in the theory of penetration of fast electrons into matter, is modified in the present paper in such a manner as to eliminate the arbitrariness in selecting the parameters of the approximating function, as well as in constructing the sought distribution. In the modified method the parameters of the approximating function are determined solely by the moments of the sought distribution and by requiring satisfaction of recurrent relationships between the moments of the approximating function. The sought distribution is represented by two (for the odd and the even distributions) infinite series of approximating functions. The terms of these series contain parameters which are found from two corresponding systems of nonlinear equations by the method of successive a pproximations, which makes it, in principle, possible to obtain a solution with any desired accuracy. In positive direction of motion of the penetrating electrons the results of this paper are very close to those calculated by Spencer, whereas in the opposite direction they diverge perceptibly.
Show AbstractA family of root loci of systems with characteristic equation $(p^3 + a_{1}p^{2}+a_{2}p+a_{3})+K(p+b_{1})=0$. is investigated. The types of root loci are determined and expressions are obtained for finding the form of the root locus from coefficients of this equation, without directly constructing the locus. A graphic geometric interpretation of variations of the types of root loci as a function of any system parameters is given. Common dynamic properties of such systems, allowing a more purposeful synthesis of the latter, are pointed out.
Show AbstractThe spectral relationships of the many - frequency synchronous mode of a self - sustained oscillatory upon many - frequency forcing at the principal tone are explored numerically by computer. The dependence of the amplitudes of the spectral components on the mistuning of frequencies of external forces for oscillators with a soft and rigid limit cycle is analyzed. It is shown that the behavior of the nonself sustained oscillator in the rigid limit cycle is primarily controlled by combinatorial interactions. Experiments performed with different units over the rf range rather satisfactorily confirm the analytic results.
Show AbstractExpressions for all the components of the elastic stress field of a dislocation glide loop are obtained in the continual isotropic approximation, in a form suitable for computer calculation. The stress fields of a chain of dislocation glide loops are calculated. Analysis shows that the field is significantly inhomogeneous and that, in order to obtain complete information on the field structure of an infinite chain it suffices to consider the field of five loops.
Show AbstractА multimode expansion chamber, filled with a moving ideal fluid, is examined. It is shown that the presence of the flow results in the appearance of the real part of the impedance matrix; here the active resistance is different for modes of different order. The flow-filled chamber is regarded as a nonmutual quadripole. Frequency curves of the levels of sound damping by the chamber at different flow velocities.
Show AbstractA method for making allowance for the inhomogeneit1es of the close environment of solute molecules on their absorption spectra is suggested. The total molecular energy is written in form of a sum of' the molecule's internal energy and the potential energy of interaction with the close environment. It is assumed that fluctuations of the second component obey a normal distribution, whereas those of the first can take only positive values. Results of using this method for reconstructing the absorption spectrum by rhodamine 6G molecules are presented.
Show AbstractStability limits of a multiresonator oscillator with lag in the nonlinear element are obtained in simple analytic form. The effect of frequency off - resonance of the individual resonators is incorporated. The dependence of the stability limits on the parameters of the multiresonator system is examined. It is shown that, under certain conditions, the presence of a fixed lag can improve the system's performance.
Show AbstractExperiments for determining the absorption coefficient of nitrogen plasma at 2820°A at temperatures from 8000 to 12,000°K are described. It is assumed, by comparing experimental and analytic values, that a stable N$^{-}$ ion in the $^{3}$Р state may form in the nitrogen plasma. The probability of decay of N$^{-}$($^{3}$P) without absorption of a photon, in the radiation spectrum, of a nonthermal component, increases with rising temperature.
Show AbstractThe problem of the motion of a tensor particle in an applied electromagnetic field is formulated. An exact solution for the motion of а particle in the field of a plane electromagnetic wave is obtained.
Show AbstractA statistical theory is suggested for describing processes in relativistic plasma on the basis of the Klimontovich method. An equation of motion of the phase density of particles and oscillators of a field is obtained; averaging it one obtains a set of coupled equations for moments. Unlike previous work, the paper considers joint distribution functions for the field's particles and oscillators.
Show AbstractThe results of work which allowed to switch, in 1980, the cyclotron to the ion-energy modulation mode and to significantly raise the intensity of the accelerated and discharged beams, are described.
Show AbstractThree - frequency $(ω_{1}+ω_{2}=ω_{p})$ parametric interaction between nonmono-chromatic waves is considered under conditions when the effect of dispersion on the no - load wave($ω_{2}$)is significantly greater than on the signal wave ($ω_{1}$). Conditions under which the no - load wave can be regarded as monochromatic are determined. The roots of the characteristic equation are investigated in this approximation, and an exact solution is obtained of abbreviated equations for amplitudes with consideration of boundary conditions.
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