A mode-locked solid-state ring laser with intracavity generation of the second harmonic
A mode-locked solid-state ring laser with intracavity generation of the second harmonic
M.R. Paleev
The intracavity generation of the second harmonic makes it possible to substantially improve the amplitude-frequency characteristics of a solid-state ring laser operating in the active mode-locking regime: to eliminate the competitive suppression of counterrunning waves, to extend the region of the beating regime, and to remove anomalies in the frequency characteristic, which are typical of the free running laser mode. The effect of the loss modulation frequency on the width of the mode-coupling region and the beat frequency is analyzed.
Show AbstractThermal explosion during laser dissociation of molecular gas
Thermal explosion during laser dissociation of molecular gas
V.E. Baklashova, B.F. Gordiets, A.I. Osipov
The kinetics of diatomic molecule photodisaociation under laser irradiation is studied theoretically for the case where heat exchange exists between the gas and the ambient medium. The mode of thermal explosion in such a system is discovered and investigated. The behavior of the entropy production function in the photodissociation process is analyzed.
Show AbstractAcoustic nonlinearity of nonuniform flow of an oscillating liquid
Acoustic nonlinearity of nonuniform flow of an oscillating liquid
A.A. Zaikin, 0.V. Rudenko
The efficiency of nonlinearity production by a localized geometrical inhomogeneity is estimated using as an example of the latter a particle layer. The Bernoulli equation for the near field and a Lighthill-type equation in the wave zone are employed in the calculation. Use is also made of the equivalent nonlinearity parameter.
Show AbstractCluster approximation for the Heisenberg ferromagnetic with nonmagnetic impurities
Cluster approximation for the Heisenberg ferromagnetic with nonmagnetic impurities
A.K. Arzhnikov, A.V. Vedyaev
An expression for the stiffness coefficient D of spin waves as a function of impurity concentration was derived for the Heisenberg ferromagnetic substance with nonmagnetic impurities in the limit of low temperatures using a simple cluster method of the Bethe-Peierls type. The pattern of the dependence was shown to change with varying concentration from $D\simeq J_0bSx/2$ at $x\sim 1$ to $D\simeq J_0bS|x—х_0|^{2\tau}$ at $x\sim x_0$.
Show AbstractMicrostresses induced by hydrogenation and plastic defomiation in palladium and its alloys with copper, platinum, hafnium, and samarium
Microstresses induced by hydrogenation and plastic defomiation in palladium and its alloys with copper, platinum, hafnium, and samarium
G.P. Revkevich, M. Mitkova, A.A. Katsnel'son, V. Khristov, G.P. Zhmurko, I.N. Avertseva
The positions of maxima in the X-ray diffraction patterns were measured and the lattice parameters $a$ were calculated for pure palladium and its alloys with Cu, Pt, Hf, and Sm. Microstresses developed in the sample surface subjected to plastic deformation by polishing increase the lattice parameter of the cubic crystal, the effect being dependent on the crystallographic orientation of the surface. Saturation of the samples with hydrogen decreases the level of microstresses and may even change their sign.
Show AbstractModel description of a plane turbulent mixing layer in a viscous fluid
Model description of a plane turbulent mixing layer in a viscous fluid
E.P. Anisimova, V.V. Petrov, A.A. Speranskaya
A model description is proposed for the average velocity profile in a plane turbulent mixing layer. The model takes into account the experimental fact of formation of coherent structures in such layers. The model was tested using data of laboratory experiments and field observations.
Show AbstractInterpretation of the 180 nm emission band observed in the spectra of discharge plasma of Kr + iodine donor composition
Interpretation of the 180 nm emission band observed in the spectra of discharge plasma of Kr + iodine donor composition
I.S. Lakoba, S.P. Chernov, P.B. Essel'bakh
A continuum band with the intensity maximum at 180 nm was detected in the emission spectrum of a discharge plasma of krypton with an admixture of iodine-containing compounds. An analysis of the experimental data allows the band to be explained by a quasi-intersection of the potential curves of excited states of the KrI molecule, not observed earlier in monohalides of inert gases.
Show AbstractThe effect of subsidiary waves on the acoustic field structure in a liquid layer
The effect of subsidiary waves on the acoustic field structure in a liquid layer
A.V. Kondrashova, K.A. Pestov, 0.S. Tonakanov
The horizontal and vertical structure of the acoustic field of the subsidiary wave, and also the integrated field of the first normal and the subsidiary waves, are considered theoretically. It is shown that under certain experimental conditions it is necessary to take into account the inftuence of the subsidiary wave on the acoustic field.
Show AbstractDefect production in gallium phosphide induced by weakly absorbed laser pulses
Defect production in gallium phosphide induced by weakly absorbed laser pulses
I.Yu. Viskovatykh, P.K. Kashkarov, V.Yu. Timoshenko
Defect production has been studied in gallium phosphide crystals irradiated by ruby laser pulses corresponding to the region of transparency for interband transitions. It has been shown that the defect production efficiency increases with an increase in the original defect density in the near-surface area resulting from the peculiarities of physical and chemical treatment of specimens. The process of defect rearrangement has been found to be athermal. The concentration of laser-induced centers of photoluminescence quenching depends nonlinearly on the laser pulse energy.
Show AbstractElectron-diffraction determination of phase structure in Pr-Fe alloys
Electron-diffraction determination of phase structure in Pr-Fe alloys
A.S. Ilyushin$^1$, N.A. Khatanova$^1$, E.A. Rykova$^1$, N.B. Kol'chugina$^2$, 0.D. Chistyakov$^2$, G.S. Burkhanov$^2$
Electron diffraction of samples of the alloy Pr-77 at.% Fe, preliminarily annealed for 100 hat 600°C, revealed the following phases: $\alpha-Pr$, $Pr_2Fe_{17}$, $PrFe_2 (С14)$, and $PrFe_2 (С15)$. The lattice parameters were determined for the hitherto unobserved intermetallic compounds $PrFe_2$ of two types: (i) $MgZn_2 (С14)$, space group $P6_3/mmc$, $а = 5,26 А$, $с = 8,62 А$ and (ii) $MgCu_2 (C15)$, space group $Fd3m$, $а = 6,76 А$. Structural-orientation correlations between these compounds and $Pr_2Fe_{17}$ were established, which shows that the three compounds can be transformed into each other.
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