The use of the reduction method to increase the resolution of photonuclear experiments
The use of the reduction method to increase the resolution of photonuclear experiments
N.G. Efimkin, B.S. Ishkhanov, Yu.P. Pyt'ev
The use of the reduction method without a priori information, invariant relative to nuclear models, helps improve the energy resolution of experimental data up to a value equal to one or two energy steps at which these data are measured. This energy resolution, which can be several times higher than the experimentally attainable one, corresponds to the full width at half maximum of a new apparatus function synthesized in the process of solving the problem and having a shape close to Gaussian.
Show AbstractThe effect of constant magnetic and light-wave fields on the luminescence polarization degree in an aqueous glycyltryptophan solution
The effect of constant magnetic and light-wave fields on the luminescence polarization degree in an aqueous glycyltryptophan solution
B.D. Ryzhikov, R.E. Shikhlinskaya
The effect of external fields on the luminescence of the (0.1-1) $mg$ $ml^{-1}$ aqueous glycyltryptophan solution was studied. It was found that the solution "memorizes" the prolonged external action of both a constant magnetic field with induction of 0.1 T and a linearly polarized quasimonochromatic light-wave field with intensity of about 1 $W m^{-2}$. On termination of the exposure, the relaxation processes had a nonmonotonic behavior of a cyclic character with characteristic times of the order of a few tens of minutes. The results obtained were interpreted in terms of the concept of an interrelation between structural rearrangements in water and conformational variations of solute molecules.
Show AbstractMethod of remote laser monitoring of photosynthesis efficiency in phytoplankton
Method of remote laser monitoring of photosynthesis efficiency in phytoplankton
M.Yu. Gorbunov, V.V. Fadeev, A.M. Chekalyuk
The method and equipment are described which allow remote measurements of the horizontal distributions of the phytoplankton photosynthetic activity to be carried out in situ aboard a moving vehicle (ship, plane, or helicopter). In the course of measurements the relative yield of the variable fluorescence of chlorophyll $a$ is determined, this quantity characterizing the efficiency of light utilization in the primary reactions of photosynthesis. It is shown that for the measurements to be correct, the photon fiux density of the activating pulse in the volume probed must be no smaller than $5 \times 10^{22} cm^{-2} s^{-1}$, that of the probing pulse must not exceed $10^{22} cm^{-2} s^{-1}$, and a time interval of 40-70 μs between these pulses must be ensured. The results of laser determinations of the photosynthetic activity of phytoplankton over extensive water areas of the North-West Atlantic are discussed.
Show AbstractThe effect of temperature and ultraviolet radiation on the luminescence spectrum characteristics of dissolved organic substance
The effect of temperature and ultraviolet radiation on the luminescence spectrum characteristics of dissolved organic substance
S.V. Patsaeva, V.V. Fadeev, E.M. Filippova, V.V. Chubarov, V.I. Yuzhakov
The specific features of the fluorescent response of dissolved organic substance (DOS) in water to optical excitation are examined: reversible and irreversible changes in the fluorescence spectra and in the fluorescence excitation and absorption spectra, induced by ultraviolet radiation and temperature variations. The results obtained are used to develop methods for diagnosing DOS, which is one of the most abundant components of natural media.
Show AbstractA study of the structure of aqueous ethanol solutions by the correlation spectroscopy and luminescent probe techniques
A study of the structure of aqueous ethanol solutions by the correlation spectroscopy and luminescent probe techniques
M.B. Berezin, L.A. Dergacheva, L.V. Levshin, A.M. Saletskii, A.V. Chervyakov
The scattered light correlation spectroscopy and luminescent probe techniques have been applied to study aqueous ethanol solutions. It is shown that adding $С_2Н_5ОН$ to water in concentrations below 10 vol.% results in adsorption of ethanol molecules on the surface of clusters, which causes an increase in their volume. Adding more ethanol destroys the clusters. An analysis of the polarization and kinetic characteristics of eosin luminescence shows microstratification to occur in aqueous ethanol solution in the range of ethanol concentrations from 20 to 80%. The scattered light correlation characteristics have been used to detennine the volume of one of the solution microphases.
Show AbstractOn the statistical theory of strength of brittle solids
On the statistical theory of strength of brittle solids
K.L. Zarembo, L.K. Zarembo
The probability of enhanced concentration of microdefects in a small volume, irrespective of its shape, was determined. This and a Griffith's type representation were used to determine the probability of rupture depending on the stress applied and to analyze the size effect and the dependence of ultimate strength on the average concentration of defects.
Show AbstractA problem of cooling control in hardening of steel
A problem of cooling control in hardening of steel
O.V. Skidanova, N.I. Kulik, V.B. Glasko, Yu.K. Evseev, S.A. Yurasov
The paper is devoted to the statement and computer solution of the inverse problem on the determination of the parameter controlling the regime of specimen cooling during hardening by providing the required cooling rate at a given depth. The investigation results can serve as a basis for elaborating automatic control systems for the technological process of thermal treatment of machine elements.
Show AbstractThe influence of redshift of the optical absorption edge on photoelectric effects in ferromagnetic $HgCr_2Se_4$ semiconductor
The influence of redshift of the optical absorption edge on photoelectric effects in ferromagnetic $HgCr_2Se_4$ semiconductor
R.Yu. Adushnaeva, I.K. Bol'nykh, G.N. Sever
In the ferromagnetic $HgCr_2Se_4$ semiconductor ($Т_с\approx108$ K), apart from the characteristic redshift of the edge of optical absorption, a redshift of photoconductivity and photo-emf spectra was also observed with decreasing temperature. The influence of magnetic ordering on the band structure also showed itself in the temperature and magnetic field dependences of these effects. Besides the peak near $Т_с$, the dependences of the relative variation of photoelectric effects in the magnetic field on temperature exhibited an additional peak at $Т>Т_c$ for the light with an energy $h\nu$, which is close to the forbidden band width. This peak may be expected to appear in the paramagnetic region for other magnetic semiconductors, too.
Show AbstractPulsed magnetization reversal in ferrite-garnet films
Pulsed magnetization reversal in ferrite-garnet films
O.S. Kolotov, V.A. Pogozhev
The literature devoted to the problem of pulsed magnetization reversal in ferrite-garnet films is briefly surveyed. The main attention is given to the flux reversal in films exposed to spatially uniform fields oriented along the easy axis. The mechanisms of pulsed magnetization reversal and their manifestation in the behavior of the principal characteristic of a material - the pulsed flux reversal curve - are considered. The effects of structural imperfections (defects and stratification) present in real ferrite-garnet films on their magnetization behavior are discussed. Problems that require further investigation are formulated.
Show AbstractOn resonance properties of the energy operator of a many-particle system in an external field
On resonance properties of the energy operator of a many-particle system in an external field
V.G. Airapetyan$^1$, V.V. Komarov$^1$, A.M. Popova$^1$, H. Neumann$^2$
The scaling method is applied to take into account the effect of an external field on the parameters of two-particle resonance phenomena in the final state of many-particle nuclear reactions.
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