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1.
Vasilyev V. N. Sazonenko D. A. Kukushkin D. E. Bakholdin A. V. Valyavin G. G. Bychkov V. D. Galazutdinov G. A. Valeev A. F. Yushkin M. V. 《Optical Review》2016,23(5):878-884
The paper presents a critical analysis and modernization of separate elements of the optical layout of a high-resolution spectrograph with fiber input for the Big Azimuthal Telescope of the Special Astrophysical Observatory. The modernization is directed mainly at enhancing the light efficiency and making it possible to produce the spectrograph using domestic manufacturers. Renovated versions of the cross-dispersion grism, the projection camera, and the overall characteristics of the system are presented. The resulting efficiency of the whole instrument is given.
相似文献2.
Approximate expressions for stress tensor components in cylindrical and ribbon crystals are obtained taking into account the temperature dependence of the thermal expansion coefficient. These expressions are used for estimating the effect of the thermal expansion nonlinearity factor on the stress level. It is shown that the stresses emerging in linear temperature fields due to this factor are comparable with critical stresses for defect formation. 相似文献
3.
V. M. Mamedov V. S. Yuferev S. I. Bakholdin Yu. G. Nosov 《Crystallography Reports》2008,53(7):1194-1202
A three-dimensional model is proposed for the global heat exchange during growth of basal-plane-faceted sapphire ribbons.
The model is based on the method for solving three-dimensional problems of radiative heat transfer in complex regions with
diffusely and specularly reflecting boundaries. The temperature distributions in the ribbon and elements of the thermal zone
are investigated. It is shown that the developed model correctly reflects the main features of the processes of heat exchange
in the crystallization setup and makes it possible to purposefully modify the thermal zone. 相似文献
4.
I. B. Bakholdin 《Fluid Dynamics》1989,24(5):750-758
The equations describing the stationary envelope of periodic waves on the surface of a liquid of constant or variable depth are investigated. Methods previously used for investigating the propagation of solitons [1–5] are extended to the case of periodic waves. The equations considered are derived from the cubic Schrödinger equation assuming slow variation of the wave parameters. In using these equations it is sometimes necessary to introduce wave jumps. By analogy with the soliton case a wave jump theory in accordance with which the jumps are interpreted as three-wave resonant interactions is considered. The problems of Mach reflection from a vertical wall and the decay of an arbitrary wave jump are solved. In order to provide a basis for the theory solutions describing the interaction of two waves over a horizontal bottom are investigated. The averaging method [6] is used to derive systems of equations describing the propagation of one or two interacting wave's on the surface of a liquid of constant or variable depth. These systems have steady-state solutions and can be written in divergence form.The author wishes to thank A. G. Kulikovskii and A. A. Barmin for useful discussions.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 5, pp. 113–121, September–October, 1989. 相似文献
5.
I. B. Bakholdin A. A. Zharkov A. T. Il’ichev 《Journal of Experimental and Theoretical Physics》2000,91(1):111-125
Soliton-type solutions of the complete unreduced system of transport equations describing the plane-parallel motions of an isotropic collisionless quasineutral plasma in a magnetic field with constant ion and electron temperatures are studied. The regions of the physical parameters for fast and slow magnetosonic branches, where solitons and generalized solitary waves—nonlocal soliton structures in the form of a soliton “core” with asymptotic behavior at infinity in the form of a periodic low-amplitude wave—exist, are determined. In the range of parameters where solitons are replaced by generalized solitary waves, soliton-like disturbances are subjected to decay whose mechanisms are qualitatively different for slow and fast magnetosonic waves. A specific feature of the decay of such disturbances for fast magnetosonic waves is that the energy of the disturbance decreases primarily as a result of the quasistationary emission of a resonant periodic wave of the same nature. Similar disturbances in the form of a soliton core of a slow magnetosonic generalized solitary wave essentially do not emit resonant modes on the Alfvén branch but they lose energy quite rapidly because of continuous emission of a slow magnetosonic wave. Possible types of shocks which are formed by two types of existing soliton solutions (solitons and generalized solitary waves) are examined in the context of such solutions. 相似文献
6.
V. M. Krymov A. V. Denisov M. I. Sallum S. I. Bakholdin V. M. Mamedov V. S. Yuferev A. A. Rusanov P. V. Smirnov 《Bulletin of the Russian Academy of Sciences: Physics》2009,73(10):1355-1359
The influence of different heat shielding constructions on the distribution of temperature and thermoelastic and residual
stresses in growing basal-plane-faceted sapphire ribbons (Al2O3) is studied. It is shown that inclined shields decrease thermoelastic stresses owing to the redistribution of heat fluxes
from a heater to a ribbon, which allows growing block-free basal-plane-faceted sapphire ribbons. 相似文献
7.
I. B. Bakholdin 《Fluid Dynamics》2000,35(4):584-590
Jumps of the bore type arising in a fluid layer with an ice sheet are investigated. These jump structures are considered for
a determining mechanism in the form of dispersion due to the presence of an ice sheet. For this purpose a generalized Korteweg-de
Vires equation [1] is used. The structure of these jumps consists of a wave zone that expand with time. On the boundary of
the wave zone there are transitions between uniform and periodic states which can be locally considered as jumps. Among them
are jumps which can be regarded as steady in the coordinate system moving with the boundary of the wave zone. These are jumps
between a sequence of solitons and a uniform state (jumps of soliton type) on the boundary of the wave zone and jumps between
periodic and uniform states (jumps with radiation). In addition, there are jumps which are unsteady even from the standpoint
of a local analysis. In order to investigate the effect of dissipation processes on the jumps considered a system of generalized
Boussinesq equations is derived with allowance for bottom slope and bottom and ice friction. The jump damping process is investigated
numerically. This system of equations also makes it possible to investigate undamped jumps of the floodwater wave type.
Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 4, pp. 139–146. July–August, 2000. 相似文献
8.
9.
P. I. Antonov S. I. Bakholdin V. M. Krymov S. P. Nikanorov 《Crystal Research and Technology》1984,19(6):769-780
The paper is concerned with the formation of a dislocation structure due the thermal stresses in shaped single crystals with different degree of anisotropy grown by Stepanov's method. The calculation of root-mean-square tangential stresses allows to determine the regions in which the plastic deformation may occur. Analysis of thermal stresses in separate slip systems permits to explaine the slipe band distribution in shaped single crystals. 相似文献
10.
The appearance of faces on cylindrical sapphire single crystals grown from a melt by the Stepanov method is studied by photogoniography and optical microscopy. The crystallographic indices of the detected faces are established, and the microstructure of the growth layers is investigated. A relationship between the faceting and the growth conditions is found. The experimental results are compared with data on the faceting of the sapphire crystals grown from a solution-melt and with the calculated specific free surface energies of the faces. 相似文献