The basic mathematical questions which come up when solving problems of interpretation and processing of experimental data in a dialog with a researcher using the rich scientific experience and specific additional information about the research object, which the scientist possesses are examined.
Show AbstractIt is shown that a variable doubling method makes it pcssible to solve arbitrary non-Hamiltonian systems of equations on the basis of the canonical perturbation theory.
Show AbstractAn effective approximate method is proposed for synthesizing directed couplers with smooth wave resistances which is based on linearization of the direct problem operator. The equation acquired in this case is thought of as an equation with an imprecisely assigned operator and a right part and is solved using A.N. Tikhonov's regularization method.
Show AbstractThe effect of the energy resolution on the angular distribution and polarization of photoelectrons in a region of two closely arrayed autoionization states is analyzed in an example of a $2p^53s^{22}P_J$ doublet of a sodium atom. The resonances in the energy relation of the coefficient of angular anisotropy and polarization of photoelectrons have a width which is different from the decay width of the autoionization state and are shifted with respect to the position of this state, General relations for the width and the shift are acquired.
Show AbstractA technique of relative widths of decay is used to analyze experimental, partial photonucleonic cross sections for a $^{23}Na$ nucleus. The probability of a half-line mechanism for decay of dipole giant resonance cf this nucleus and individual photonucleonic channels is determined.
Show AbstractThe work is dedicated to a nonlinear theory of parametric beam-plasma instabilities with consideration of distortion of the transvers structure and polarization of the waveguide modes. Analytical solutions are acquired of nonlinear equations which are written with a precision to cubic members. The role of reordering of a waveguide mode structure at the instability saturation stage is evaluated.
Show AbstractA model is proposed for investigating the spectrum and kinetics of cascade excitation of curves, three-atom molecules by a powerful infrared (IR) pulse. The effect of the resonance anharmonic interaction on the position of the oscillatory levels of $O_3$ is analyzed and the results of the calculation are compared with the experimental data. Based on the calculated spectroscopic information about the channels and cross sections of the cascade IR excitation, the kinetics of the ropulations of the lower oscillatory levels of the $O_3$ molecules are modeled.
Show AbstractThe problem of transforming an electrical video signal into an optical image using an acoustooptical cell with amplitude and ohase modulation of the acoustical wave is examined. Expressions are acquired for the space-frequency characteristics of the cell in cases of isotropic and anisotropic diffraction of light. It is shown that the maximal resolution of the cell is determined either by the band of tte piezoconverter or by the selective properties of acoustooptical interaction.
Show AbstractThe reflection of a surface acoustical Rayleigh wave from the rib of an acutely angled elastic wedge with slanted incidence is theoretically investigated. An approximate approach is used for solving the problem which is based on geometrical optics (acoustics). One of the most interesting results of the performed analysis is establishment of the fact of existence of a substantial effect ot the phase shift of the symmetrical mode of the field, which forms with its reflection from the caustic (the caustic phase shift), on the angular relation of the modulus of the reflection coefficient.
Show AbstractAn experimental investigation is performed of the dependence of the amplitude of the second and third acoustical harmonics of a shift wave propagated in an iron-yttrium garnet crystal (a wave frequency of 30 MHz) from an external magnetic field. A rise in the amplitude of the harmonics and distortion of the shape of the initial sinusoidal wave which passes through the crystal are noted in the range of magnetoacoustical resonance. The measurements were taken for different directions of the external magnetic field and an additional magneitizing field (localized in the center of the crystal).
Show AbstractThe space and time statistical characteristics of high intensity diffracting acoustical noise are theoretically investigated. It is established that nonlinearity leads to a "spreading" of the energy along the spectrum and, in the same way, has a strong additional effect on the frequency-dependent diffraction effects. The dependences of the radius of correlation on the distance and the cross section of the correlation function in the space-time coordinates are built for different relations between the nonlinear and diffraction lengtns.
Show AbstractAn expression is acquired for the elevations of the surface of a level and the interface with forced oscillations. It is shown that the basic wave energy is concentrated on the interface of the layers of the vicinity of resonances.
Show AbstractThe described method is based on a) an empirical formula which links the measured subsurface currents of photosynthetically active solar radiation (PSASR) (at 350-700 nm) with the appropriate measured positions of the Sun and b) astronomical formulas for the position of the Sun relative to the time of the day, the day of the year, and the geographic latitude. In accordance with this, precise daily and annual integrals of the currents of PSASR and the form factors of the daily change in the PSASR current are given. Certain consequences for calculating the production of phytoplankton are discussed, in particular, the effect of the form factors of the daily changes in the PSASR current.
Show AbstractUsing the thermodynamic relation between the constants of the anomalous Hall effect and the anomalous Nernst-Ettingshausen effect (ANEE), the ANEE constant is acquired of alloys for high and low scattering. A conclusion is drawn on a comparison between the experiment and the theory that the Fermi level in Ni and in Ni-Pd alloys with a Pd concentration less than 70% is located at an energy less than the corresponding maximum of the density of the electron states.
Show AbstractX-Ray analysis of fixed monocrystals was used to investigate the crystalline. structure of titanium nickelide alloys with vanadium, niobium and tantalum. It is shown that doping leads to stabilization of the B2-structure and to a reduction in $M_s$. With doping along the NiTi-metal (Me) section the stabilization is less substantial when with doping along the NiTi-NiMe and NiTi-MeTi sections. The listed pacterns are explained on the basis of an examination of the role of the dimensional factor.
Show AbstractPrecise classical wave solutions are acquired for movement equations for the SU(2) Young-Mills fields which interact with an isodoublet of Higgs bosons. It is shown that the classical effective action of $W^{(0)}$ has a nonanalytical dependence on the parameter of the problem $\nu = 4\lambda/g^2$. The special point $W^{(0)}$ corresponds to the resonance behavior of the amplitudes and frequency of the intensity of the Young-Mills and Higgs fields.
Show AbstractIt is shown that the first approximation to the force of radiation braking greatly exceeds all of the higher corrections to it even for the most rapidly changing fields and for the highest which can be achieved in a laboratory. These corrections themselves lie on the boundary of experimental detection.
Show AbstractThe measurements were taken by the Sokol instrument installed aboard the Kosmos-1543 satellite. Differential energy spectra of primary nuclei of carbon and oxygen and nuclei of the iron group are acquired in an energy range of 50-1000 Gev/nucleon. A comparison is performed with the results of other works.
Show AbstractThe use of a laser operating in mode locking regime may improve the spatial distribution of a monostatic doppler lidar for measuring wind velocity. It is determined in this case by the duration of picosecond pulses and may be several centimeters at a distance of approximately 100 m. A laboratory mock-up of the lidar was used to perform speed measurements, to determine the correlation function of a field, and to calculate the power of a doppler signal received from a unit of length the route.
Show AbstractThe change in the spectral characteristics cf aqueous dye solutions relative to admixtures of different surfactants contained in them is studied. It is shown that the observed increase or decrease (up to 50%) with small additions of surfactants in the absorptive and luminescence properties of the solutions is caused by a change in the magnitude of adsorption of the molecules of the dissolved material on the boundary of the solution.
Show AbstractPropagation of volumetric acoustical waves (VAW) and surface acoustical waves (SAW) was investigated in a $Bi_2WO_6$ crystal. Values of the moduli of elasticity $C_{22}$ and $C_{36}$ are acquired along with the value for the pseudo-modulus $d_{24}$. The anisotropy of the speeds and losses to conversion is investigated for SAW excited in the [010] plane of the crystal using an interdigital converter. The possibility of using natural plates of the crystal as a VAW converter is investigated.
Show AbstractThe electromodulation spectra of maximally high resistance (MHR) GaAs(O) with a specific dark resistance of 300 K of $\rho \approx 2\cdot 10^9$ $\Omega \cdot см$ are investigated. In this material the deep donor level of oxygen is greatly filled with holes, which makes it possible to examine their photoionization in a valent zone. Resonance peaks of electroabsorption are recorded in the electromodulational spectra which are associated with the particular transitions. The energy of ionization of the donor (D) level of the oxygen is equal to $\epsilon_{Dv}=0.76\pm0.01$ eV and is constant in a range of 80-300 K.
Show AbstractA new classification is proposed fer the varieties of Mossbauer phase analysis (MPA): 1) qualitative MPA of regular sructures, 2) quantitative MPA of regular structures, and 3) MPA of defect, amorphous, and similar systems. This classification, unlike the traditional (which only includes the first two varieties), more fully and correctly reflects the methodological potential of M$\stackrel{..}{o}$ssbauer spectroscopy when solving problems of phase analysis of materials.
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