Adaptive optical system with systematic probing
Adaptive optical system with systematic probing
M.A. Vorontsov, I.A. Kudryashov
A model of an adaptive optical system of aperture probing with systematic introduction of variation in the phase of the light wave is investigated. The system has three control loops and permits stabilization of the position of the coherent light beam in space (two control loops) and automatic focusing of this beam.
Show AbstractParametric difference-frequency generation in the field of a multimode pumping wave
Parametric difference-frequency generation in the field of a multimode pumping wave
V.A. Aleshkevich, V.Ya. Gaivoronskii, A.N. Matveev, V.A. Trofimov
Parametric generation in the field of a multimode pumping wave is investigated numerically and analytically, in the case when diffractional effects are significant. The dependence of the efficiency of energy transformation and the degree of coherence of the wave generated on the number of spatial inhomogeneities of the pumping beam is analyzed. It is shown that, in conditions of strong energy transfer, conditions of self-channeling of the individual inhomogeneities set in, and the efficiency of the process at the length of diffractional reduction of the phases is practically independent of the initial mode composition of the pumping wave.
Show AbstractSound-wave propagation in acoustooptical crystals of paratellurite and calomel
Sound-wave propagation in acoustooptical crystals of paratellurite and calomel
M.A. Voronova, V.N. Parygin
The acoustic field of a slow quasi-shear wave created by a plane converter with a Gaussian aperture function close to the crystallographic direction [110] is investigated for paratellurite and calomel crystals. The parabolic approximation of the wave-vector surface is used. The dependence of the parabolic-approximation coefficients on the wave-vector direction is given. The limits of parabolicity are given. The method of calculating the geometry of the acoustic beam excited along the axis [110] is considered.
Show AbstractPressure pulsations at the surface of a sphere in a fluid flow
Pressure pulsations at the surface of a sphere in a fluid flow
F.V. Rozhin, O.S. Tonakanov, S.G. Mikhailov
Experimental results are given for the distribution of pressure pulsations as a function of the angle between the direction of the fluid flow and the position of pulsation detection by a small sensitive element. Angular and spectral characteristics of the pressure pulsations are obtained at small flow velocities (0.25 and 0.5 m/sec). It is shown that the maximum pulsations are obtained in the "dark" part of the sphere in the turbulized flow region.
Show AbstractSlow induction of fluorescence in leaves of higher plants grown in various light conditions and also in the presence of chemical agents (antimycin A and $NH_4Cl$)
Slow induction of fluorescence in leaves of higher plants grown in various light conditions and also in the presence of chemical agents (antimycin A and $NH_4Cl$)
I.O. Belogrudov, V.A. Karavaev, A.K. Kukushkin
Variation in the parameters of slow induction of fluorescence is studied as a function of the light intensity during growth. The relation between the inductional transitions of fluorescence and the functional activity of the photosynthetic apparatus is shown. The action of chemical agents (antimycin A and $NH_4Cl$) on the kinetics of slow induction of fluorescence is also studied.
Show AbstractLaser nickel plating of semiconductors
Laser nickel plating of semiconductors
A.A. Eremenko, V.V. Zadde, A.K. Zaitseva, E.K. Kozlova, A.I. Portnyagin, A.N. Romanchenko, A.E. Filippov
The action of laser radiation on the semiconductor-electrolyte system leads to acceleration of the reduction of nickel and/or ordering of the residue structure. The mechanism of increase in the deposition rate is associated with a set of thermal and electrical influences of laser radiation on the given system.
Show AbstractTernary superstructure in alloys of the quasi-binary system $Ho(Fe_{1-x}Mn_x)_2$
Ternary superstructure in alloys of the quasi-binary system $Ho(Fe_{1-x}Mn_x)_2$
A.S. Ilyushin
The nuclear gamma-resonance method is used to study the local distribution of atoms in the 3d sublattice of intermetallides in the quasibinary system $Ho(Fe_{1-x}Mn_x)_2$ and a ternary superstructure of stoichiometry $Ho(Fe_{0,25}Mn_{0,75})_2$ is observed.
Show AbstractDevelopment of contactless ultrasonic methods of investigating solids
Development of contactless ultrasonic methods of investigating solids
A.N. Vasil'ev
Utilizing the direct transformation of electromagnetic and acoustic waves in conducting media offers the possibility of a fundamentally new approach to the formulation of the ultrasound experiment. Contactless methods that have been based on this phenomenon for changing the velocity and damping of ultrasound in metals and semiconductors are described.
Show AbstractMechanism of current transfer in surface-barrier structures p-Si/polymer material/$SnO_2$
Mechanism of current transfer in surface-barrier structures p-Si/polymer material/$SnO_2$
V.E. Senyuk, G.G. Untila, A.L. Kharitonov, L.B. Rubin
The temperature dependence of the volt-ampere characteristics of photoelectric converters (PEC) p-Si/polymer material/$SnO_2$ is investigated for samples with different levels of silicon doping. The relation is established between the mechanism of current-carrier transport and the no-load potential $V_{хх}$. It is shown that the reduction in $V_{хх}$ with increase in the level of silicon doping may be associated with increase in the PEC dark current on account of the multistage-tunneling mechanism.
Show AbstractThermoemf in relaxational conditions
Thermoemf in relaxational conditions
Yu.P. Drozhzhov
A relaxational semiconductor with an injective contact is considered. It is shown that a term that is activationally dependent on the temperature may appear in the expression for the thermoemf of the sample, in the given conditions.
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