Active Bragg Compressor of 3-cm Wavelength Microwave Pulses

We present the results of studies of the active compressor of 3-cm wavelength microwave pulses, which uses a high-Q storage Bragg resonator excited at the H₀₁ mode and new types of plasma switches. Phase variation during a compressed pulse and phase correlation of the input and compressed microwave pulses are studied both experimentally and theoretically. Using a single-channel compressor excited at the megawatt power level by the magnicon radiation with frequency 11.4 GHz, a power amplification factor equal to 9 was reached for an output-pulse duration of 40–50 ns and a peak power of up to 25 MW. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 51, No. 7, pp. 597–616, July 2008.     

Measurement of the activity of an artificial neutrino source based on 37Ar

The activity of an artificial neutrino source based on ³⁷Ar was measured by a specially developed method of directly counting ³⁷Ar decays in a proportional counter. This source was used to irradiate the target of the SAGE radiochemical gallium—germanium neutrino telescope at the Baksan Neutrino Observatory (Institute for Nuclear Research, Russian Academy of Sciences, Moscow), whereupon the measurements were performed at the Institute of Reactor Materials (Zarechny, Sverdlovsk oblast, Russia). The method used to prepare gaseous samples for measurements in proportional counters and the counting procedure are described. The measured activity of the ³⁷Ar neutrino source is 405.1 ± 3.7 kCi (corrected for decays that occurred within the period between the instant of activity measurement and the commencement of the irradiation of Ga target at 04:00 Moscow time, 30.04.2004).     

Teleportation through <Emphasis Type="Italic">W</Emphasis>-class states

The possibility of using entangled states of the W class either as a quantum channel for teleportation or as states to be teleported is analyzed. The protocols are determined through the unitary transformation of the schemes based on the Greenberger-Horne-Zeilinger (GHZ) channel. It is shown that the main feature of new quantum channels of the W class is a set of nonlocal operators capable of recovering an unknown state.     

Solar-neutrino results from SAGE

The solar-neutrino-capture rate measured by the Russian-American Gallium Experiment on metallic gallium during the period from January 1990 to December 1997 is (67.2 _?7.0?3.0 ^+7.2+3.5 ) SNU, where the uncertainties are statistical and systematic, respectively. This result represents a 7σ depression in the neutrino flux in relation to the predicted standard-solar-model rates. The experimental procedures used and data analysis are presented.     

Kinetic Equation for Micromaser Generation by Correlated States of Atoms

A kinetic equation for the light generated by atoms with states prepared by a pumping mechanism producing atomic correlation is derived in a rigorous way. It is found that only two-particle correlations need to be taken into account within the framework of the Fokker–Planck approximation. The kinetic equation derived is applied to the process of micromaser operations and the light noise is discussed. A new mechanism of pumping based on correlated atomic states prepared by telecloning protocols is considered.     

Positron annihilation in radiation capture centers in quartz and quartz glasses

This study presents the results of a theoretical and experimental investigation of the process of positron annihilation in radiation capture centers (RCC) of quartz and quartz glasses irradiated byγ-rays. The value of the effective electron mass in the oxygen bridge atom vacancy (E′ center) is determined. This value proves to be larger than in the case of a quartz monocrystal and close to the value calculated from the optical absorption band of quartz glass (μ ～ 5.0 m_e). It is shown that positron annihilation in [A1] centers is characterized by a greater half-width in the annihilation radiation angular correlation curve than in H-centers. The dependence of radiation capture center concentration on radiation dosage is obtained.     

Some observations regarding the compensation effect observed in the kinetics of non-isothermal transformations

A kinetic equation is analyzed whose application in practice for a number of transformations will demonstrate the linear correlation between activation energy and InA (the preexponential factor in the Arrhenius equation).     

Symmetry of lattice vibrations of hexagonal Cu2Te

The vibrational representation is expanded in terms of irreducible representations at the principal symmetry points of the Brillouin zone. Selection rules are found for single-phonon IR absorption, Raman scattering, and Mandel'shtam-Brillouin scattering of light. In IR absorption, a single frequency is active for light polarized parallel to the sixth order axis and a single frequency for perpendicular polarization. Five frequencies are active in Raman scattering of light. Expansions of the direct product of irreducible representations (selection rules) are found.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 45–48, November, 1981.     

Logistic heating program in thermal analysis and non-isothermal kinetics

Use of the logistic rule is proposed for programmed heating in thermal analysis. An algorithm is presented for solving the temperature integral of non-isothermal kinetics.