Properties of multilayer interference absorber with, oblique incidence of radiation
Properties of multilayer interference absorber with, oblique incidence of radiation
A.N. Baskakov, A.V. Tikhonravov
The angular properties of a multilayer interference absorber (MIA) are theoretically investigated. It is shown that, with inclination of the MIA, its resonant curve is shifted into the short-wave region, and the magnitude of the shift is proportional to the square of the angle of incidence of the radiation. A simple expression is obtained, describing the form of the central lobe of the MIA directionality diagram. The laws for the suppression of external noise in receivers with MIA at the inlet are discussed, together with the possibilities of tuning these receivers with respect to the resonant frequency following from the MIA angular properties.
Show AbstractTypes of root trajectory of linear and linearized fourthorder systems
Types of root trajectory of linear and linearized fourthorder systems
G.A. Bendrikov, V.I. Miftakhov
The root hodographs of fourth-order systems described by the characteristic equation $(a_0p^4+a_1p^3+a_2p^2+a_3p+a_4) +К=0$ are considered. In the plane of the two parameters M and N, which are functions of $a_i$, regions determining all the possible types of root trajectory are isolated. From the analysis of types of hodographs, the general dynamic properties of such systems are established, allowing their investigation and calculation to be simplified.
Show AbstractSpectra of nascent wind waves
Spectra of nascent wind waves
G.E. Kononkova, К.V. Pokazeev
The spectra of wind undulation with startup distances of less than 4 m and dynamic velocities of 35 to 90 cm/sec are considered. The difference in the dependence of the spectra on the dynamic velocity and frequency under these conditions in comparison with the spectra of wave disturbance at large distances is explained by the action of drift flow.
Show AbstractStructure of triple dislocation points forming in the course of dislocational reactions in hcp crystals
Structure of triple dislocation points forming in the course of dislocational reactions in hcp crystals
G.V. Bushueva, E.M. Yakhshaatova
The moment method is used to investigate the structure and stability of triple spatial dislocational points in hep crystals. It is shown that the moment method offers the possibility of more rigorous estimation of the conditions of occurrence of dislocational reactions than the Frank criterion. The "moment" criterion allows the region of guaranteed occurrence of dislocational reactions to be determined, i.e., the region of mutual orientations of the dislocations for which the occurrence of reactions between them is favorable.
Show AbstractElectrostatic acceleration of a modulated electron beam
Electrostatic acceleration of a modulated electron beam
Yu.K. Alekseev, A.I. Kostienko
The problem of pumping power into a modulated electron flux is considered. It is shown that, with dynamic modulation of the flux, power pumping leads to slowing of the grouping process and reduction in beam efficiency. In the case of electrostatic control of the current's form however, its spectral composition and electron efficiency are retained.
Show AbstractDetermining the plasma potential from the ionic part of the volt-ampere characteristic of an electrical probe
Determining the plasma potential from the ionic part of the volt-ampere characteristic of an electrical probe
V.S. Nikolaev
A method of determining the plasma potential is proposed, on the basis of the ionic part of the volt-ampere characteristic of an electric probe.
Show AbstractInhomogeneous magnetic state in the system of solid solutions $(1-x)$Cu$_{0,5}$Al$_{0,5}$Cr$_2$S$_4$-$x$CuCr$_2$S$_4$
Inhomogeneous magnetic state in the system of solid solutions $(1-x)$Cu$_{0,5}$Al$_{0,5}$Cr$_2$S$_4$-$x$CuCr$_2$S$_4$
L.I. Koroleva, A.I. Kuz'minykh, I.V. Gordeev, Ya.A. Kesler
The magnetic and electrical properties of the system of solid solutions $(1-x)$Cu$_{0,5}$Al$_{0,5}$Cr$_2$S$_4$-$x$CuCr$_2$S$_4$ are studied. All the compositions studied have semiconductor conductivity of $p$ type. The dependence of the magnetization on the field strength is a superposition of the magnetization characteristic for an antiferromagnet and the small spontaneous magnetization. The spontaneous moment corresponding to one impurity ion Cu$^{2+}$ is close to the magnetization of the ferromagnetic cluster Cr$^{3+}$ formed by Cr ions, the nearest neighbors of Cu$^{2+}$. It is suggested that these clusters (ferrons) are created by localization of holes around the acceptor copper ion because of the energy gain of $s$-$d$ exchange. The presence of ferrons in these materials is also confirmed by the sharp rise in paramagnetic susceptibility in the region of the Curie point. Estimates of the magnitude of $s$-$d$ exchange in these materials are given.
Show AbstractTwo-photon absorption cross section at $F_{2}^{+}$ centers of alkalihalide crystals
Two-photon absorption cross section at $F_{2}^{+}$ centers of alkalihalide crystals
V.F. Kamalov, Yu.P. Svirko
The nonlinear optical susceptibilities of $F_{2}^{+}$ centers in alkali-halide crystals are calculated. Values of the energy and dipole moments of transitions determined within the framework of the model of the molecular hydrogen ion allow the two-photon absorption cross section of a series of optical transitions.
Show AbstractLight reflection from the interface of media with thermal nonlinearity
Light reflection from the interface of media with thermal nonlinearity
S.P. Chernov, A.V. Shepelev
Consideration is given to nonlinear thermal reflection, which consists in change in the Presnel reflection coefficient with heating of the interface by radiation. A theory of this effect is proposed, and results are given of its experimental investigation and application for resonator Q-factor modulation. The possibility of using the effect for the anodization of radiation is discussed.
Show AbstractMeasuring the energy characteristics of a sound field in an interferometer
Measuring the energy characteristics of a sound field in an interferometer
A.N. Ivannikov, F.Y. Rozhin, O.S. Tonakanov
The basic relations characterizing the parameters of a sound field in an interferometer are considered. An experimental apparatus and procedure is described, allowing the characteristics of the reflective surface to be described on the basis of measurements of the power flux density.
Show Abstract