Heat energy balance in a low-pressure SHF surfatron
Heat energy balance in a low-pressure SHF surfatron
P.S. Bulkin, A.P. Ershov, G.S. Solntsev, M.M. Rakhman, L.I. Tsvetkova
Analysis is presented of the results of experimental studies of a radial heat flow $Q_T (z)$ along the plasma column of an SHF surfatron in Xe at a pressure of 0.5-1.2 Torr. Energy loss caused by the energy transfer to the walls by positive ions accelerated by the ambipolar diffusion field and the potential gradient near the discharge tube wall was found to play an important part. This channel of energy loss is most effective in heavy gases. In the experimental conditions of this study. the properties of the discharge along its total length can be described by means of a single kinetic plasma model.
Show AbstractTrigonal germanium dioxide: its preparation and optical parameters
Trigonal germanium dioxide: its preparation and optical parameters
T.M. Glushkova$^1$, D.F. Kiselev$^1$, I.B. Makhina$^2$, M.M. Firsova$^1$, A.P. Shtyrkova$^1$
The following physical properties of trigonal germanium dioxide grown by the hydrothermal method at 185°C were studied: density, the refractive and optical specific rotatory dispersions in the visible spectral range, and the spectra of optical transmission over the 0.2-10 μm range. The data obtained were compared with the same parameters for $\alpha $-quartz, which is a structural analog of trigonal germanium dioxide.
Show AbstractChanges in the mechanical and electric parameters of bilayer lipid membranes in their interaction with hematoporphyrin
Changes in the mechanical and electric parameters of bilayer lipid membranes in their interaction with hematoporphyrin
T. Hianik$^1$, D. Masarikova$^1$, L.V. Zhorina$^2$, M.Yu. Poroshina$^2$, E.B. Chernyaeva$^2$
The interaction of hematoporphyrin IX (HP) with artificial bilayer lipid membranes (BLMs) has been studied. It has been found that after dark incubation of BLMs in a HP solution (at concentrations from $10^{-6}$ to $3 \cdot 10^{-5}$ M) the conductance of the BLMs does not change very much, the elasticity modulus ( $E_{\perp}$ ) and the dynamic viscosity coefficient $\eta$ diminish by 21.9-31.3%, while the membrane potential $U_1$ becomes negative (-50 mV). Irradiation of a modified BLM by a He-Ne laser leads to an increase of the parameters $E_{\perp}$ aud $\eta$ by 40.7 to 66.2%, to a decrease of $U_1$ to -20 mV, and also to irreversible changes in the mechanical properties of the membrane. Binding of HP with BLM proceeds noncooperatively with the constant $К = 10^{5}$ $М^{-1}$.
Show AbstractDynamics of stimulated Raman backscattering: numerical experiment
Dynamics of stimulated Raman backscattering: numerical experiment
I.N. Zhmakin, S.Yu. Nikitin, D.A. Sivashov
The dynamics of Raman backscattering was studied under conditions when the duration of the pumping pulse was greater than the dephasing time for molecular vibrations and the time of light travel through the medium. Three basic regimes were found to be possible: quasistatic, spiking, and transient. Realization conditions and specific features of these regimes were established.
Show AbstractOptimization interference coatings in adaptive radio-optical devices
Optimization interference coatings in adaptive radio-optical devices
I.N. Sisakyan, A.V. Tikhonravov, A.B. Shvartsburg, A.V. Shepelev, V.G. Yakushkina
Quantitative calculation of optimization coatings based on the analysis of the field-dependent optical properties of semiconductor materials in the far-infrared region has been made. The amplitude-phase characteristics of the adaptive radio-optical devices were computed. It has been shown that optimization interference coatings make it possible to increase the dynamic ranges of amplitude modulation systems by a factor of 3 to 4.
Show AbstractGravitational waves and baryosynthesis
Gravitational waves and baryosynthesis
M.V. Sazhin, Ya.A. Chechina
Manifestations of the dust-dominated stages, which might take place in the early Universe, are analyzed. One of possible causes of such stages is baryosynthesis at temperatures T = 1015 GeV. Distortions in the spectrum of the gravitational wave background, brought about by the stage of baryosynthesis, are calculated.
Show AbstractCalculation of an optical system for a laser-controlled gyroscop
Calculation of an optical system for a laser-controlled gyroscop
V.E. Zharov, S.N. Markova, M.V. Sazhin, E.N. Fedoseev
A passive square-shaped resonator is proposed to be used in the laser gyroscope system being developed at the Time Service Department of the Sternberg Astronomical Institute for measuring the Earth's rotation variations. The resonator has an arm l of 3.10 m and consists of two spherical mirrors of equal radius of curvature ($R_m$ = 10 m) and two flat mirrors, one of which is an input element and the other the output element.
Show AbstractConduction anisotropy induced by the electric field in narrow-gap Bi-Sb semiconductors
Conduction anisotropy induced by the electric field in narrow-gap Bi-Sb semiconductors
E.V. Bogdanov, T.G. Kustova
Heating of charge carriers in specimens of $n$- and $p$-type Bi-Sb semiconductor alloys whose axes are noncoincident with the crystallographic axes, gives rise to a transverse electric field. The specific features of this phenomenon were qualitatively explained in term of the theory of the Sasaki-Shibuya effect and the well-known concepts of the energy spectrum of these narrow-gap semiconductors.
Show AbstractElcctricral properties of crystals of the formate and urea groups
Elcctricral properties of crystals of the formate and urea groups
N.D. Gavrilova, N.P. Zaitseva, G. L. Slabkaya, L.V. Soboleva, S.V. Bogatyreva
The temperature dependence of electrical conduction was studied and the activation energy was calculated for crystals with long hydrogen bonds, viz., lithium, yttrium, holmium, and erbium formates, urea and thiourea. A weak pyroelectric effect was revealed in the urea crystal at a temperature below room temperature. At temperatures below the phase transition temperature ($Т_С$ = 169 K) in weak electric fields, the thiourea crystal showed anomalies associated with a change in the behavior of protons on hydrogen bonds.
Show AbstractThe matgnetic properties of $Gd_xCe_{1-x}MnSi$ compounds
The matgnetic properties of $Gd_xCe_{1-x}MnSi$ compounds
S.A. Nikitin, 0.V. Nekrasova, T.I. Ivanova, Yu.F. Popov
The magnetic properties of the $Gd_xCe_{1-x}MnSi$ system of rare-earth compounds were studied. The Neel temperatures $T_N$ were determined for alloys with a Gd concentration in the range $0\le x\le 0,4$ and the Curie temperature $Т_С$ of alloys with a Gd concentration $x\ge 0,5$. The magnetic moments per formula unit were calculated. The curves of specific magnetization $\sigma$ versus magnetic field have showed, in the $0,2 < x < 0,6$ range of Gd concentration, sections corresponding to the threshold fields $В_{th}$, where $\sigma$ starts to grow sharply. A magnetic phase diagram was plotted and regions of existence of ferri-, antiferro-, and paramagnetic states were deterinined. A model was proposed to explain the magnetic properties of the compound, which assumes that there exists an antiferromagnetic exchange interaction between the Mn layers and a ferrimagnetic ordering of the Mn magnetic monents and rare-earth ions.
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