Vol 10, No 1 (2016)

IR photoluminescence of bismuth-doped ternary thallium chloride TlCdCl₃ was studied. Two bismuth-containing luminescence impurity centers were detected. One of these was found to be the bismuth Bi⁺ monocation, emitting at 1025 nm.

The removal of a lead film from graphene by irradiating a target with a beam of xenon clusters at an incidence angle of 60° was studied by the molecular dynamics method. The complete purification of graphene was achieved at beam energies of 10 and 15 eV. Visual observation and the calculated density profiles and mobility components of the lead atoms indicate the predominantly collective nature of the separation of Pb from graphene in the course of bombardment. When a beam of clusters with an energy of 15 eV acts on the target, the detached film of lead takes a torch shape and has strong internal stresses. The graphene sheet acquires maximum roughness at a beam energy of 10 eV as a result of a large number of the direct hits of xenon clusters on its surface.

The dependence of the conductivity of poly(p-xylylene)-based titanium-containing nanocomposites on the extent of adsorption of polar molecules from the atmosphere is observed, while nonpolar molecules induce no such changes. A relationship between the dipole moment of the adsorbate molecule and the sensitivity of the composite conductivity to its vapor is revealed. A composite with filler content near the percolation threshold shows the highest sensitivity to polar gases. A model is proposed to explain the change in the resistance upon vapor adsorption by the formation of a surface dipole. Since the investigated vapors are adsorbed as donors, their adsorption reduces the electron work function of the nanoparticles, thereby increasing the conductivity. The dielectric spectrum of a nanocomposite containing 2 vol % titanium dioxide is very closely approximated by the Cole–Cole and Maxwell–Wagner equations, whereas the frequency dependence of the electric modulus is close to that predicted by the Debye law.

The effect of an electric field on the surface combustion of both lean and rich stirred gas mixtures was studied. The voltage–current characteristics of a current flow through gas were constructed. It was found that the confinement of surface combustion and a decrease in the temperature of a wire screen over the matrix are possible in the presence of an electric field. A change in the matrix polarity from negative to positive leads to an increase in electrical current in the circuit by an order of magnitude. Upon the arrangement of an impenetrable screen over the matrix, the matrix temperature can increase or decrease with the negative or positive polarity of the matrix, respectively.

Experimental results have shown that the use of inorganic oxidizers (ammonium nitrate, ammonium perchlorate, and ammonium dinitramide) as additives does not lead to a considerable increase in the heat of explosion and acceleration ability of HMX. Ammonium perchlorate does not have an effect on the acceleration ability; however, it leads to an increase in the heat of explosion of triaminotrinitrobenzene. Calculations have shown that the acceleration ability of explosives with a low oxygen ratio can be increased through the formation of nanostructured composites with inorganic oxidizers. Calculations suggest that the addition of the studied oxidizers to CL-20 leads to a decrease in the acceleration ability of this promising explosive.

The magnitude and character of conductivity were studied for Y₂(WO₄)₃ ceramics synthesized by the ceramic (from oxides) and organic-nitrate procedures. Investigation of the dependence \(\sigma \left( {{\alpha _{{o_2}}}} \right)\) and measurements of the ion transport numbers of charge carriers by the EMF method showed that Y₂(WO₄)₃ is basically an ion conductor. The conductivity is largely determined by the sample preparation conditions related to the dependence of the specific surface area and powder grain size on the synthetic procedure. The maximum high-temperature conductivity of Y₂(WO₄)₃ was 2.51 × 10^–4 S/cm, which roughly corresponds to the conductivities of Sc₂(WO₄)₃ and In₂(WO₄)₃ measured under the same conditions. It was confirmed that Y₂(WO₄)₃ crystallizes as a mixed monoclinic-orthorhombic structure at 1000°C. The character of water incorporation in hydrated Y₂(WO₄)₃ crystals was studied by thermogravimetry and diffuse reflectance IR spectroscopy. A qualitative model of water intercalation was suggested.

Superradiance induced by the rheological explosion of composites based on polystyrene, cobalt acetylacetonate, and/or 3,5-di-tert-butylcatechol has been investigated. The superradiance intensity is determined by solid-phase chemical reactions induced by the rheological explosion. EPR, X-ray diffraction, and electron microscopic characterization of stable products resulting from the rheological explosion in the polymer matrix has demonstrated that the superradiance intensity is related to the electronic properties and structure of two-spin intermediates, namely, radical pairs and organoelement biradicals.

Basics of the radiochemical physics of the Earth atmosphere are discussed. This area of science studies the resonance interactions of the electromagnetic waves with the gaseous media containing the Rydberg molecular complexes that occupy D and E layers of the upper atmosphere during solar flares. This interaction is responsible for the distortion of the signals from the satellite groups. The radiation transitions between orbitally degenerate states of these complexes form the non-coherent additional background radiation on the radio (UHV) and infrared (IR) ranges. The radiation in these wave ranges is of primary importance in a number of fundamental researches and is widely used in some technical applications. The areas considered in this paper include: the dynamics of processes in the upper atmosphere during increase of solar activity leading to the formation of incoherent additional background radiation; the distant passive location of the soil humidity and the salinity of the ocean waters; the distant radio sounding of the electromagnetic properties of the surface layers of the Earth for determining their structure and content; the technology of efficient and uninterrupted operation of energy networks by synchronizing the measuring equipment in view of the possible failures of the satellite signals; the use of the global positioning systems as a tool for monitoring the state of the atmosphere. In the present work the description is given of the most perspective applications of the above mentioned areas of the radiochemical physics of the atmosphere whose robustness is substantially depends on the current state of the upper atmosphere. We analyze the problems that arise here and provide their specific solutions. The prospects for the development of these applications are discussed, as well as those areas of research that are just coming up.

The major morphological features of the global structure and longitudinal variations of the electron content distribution in the ionosphere–protonosphere system during the winter solstice for the solar activity minimum in 2009 are examined. It is demonstrated how the Weddell Sea anomaly and the longitudinal structure of the main ionospheric trough (depression in the concentration of light ions) manifest themselves through the total, ionospheric, and protonospheric electron contents. Based on model calculations, the specific features of longitudinal variations in the O⁺/H⁺ transition altitude are for the first time considered, which made it possible to estimate the altitude of the transition boundary from the ionosphere to the plasmasphere (protonosphere) for the selected conditions.

The results of numerical simulations of the effects of a sudden stratospheric warming (SSW) in January 2009 are examined. The calculations are performed within the framework of the Global Self-Consistent Model of the Thermosphere, Ionosphere, Protonosphere (GSM TIP), which calculates the parameters of the neutral and charged components of the upper atmosphere. An analysis of the numerical simulation results showed that the perturbation of mesospheric tidal and planetary waves significantly affects the structure of variations of the thermosphere at altitudes below 150 km. At higher altitudes, the characteristics of planetary and tidal waves in the thermosphere are practically insensitive to the corresponding mesospheric perturbations. The calculated space–time structure of ionospheric perturbations caused by mesospheric and planetary tidal waves is in qualitative agreement with observation data. The results show that the main reason for the observed ionospheric effects is the perturbation of the electric fields in the dynamo region. However, the calculated magnitudes of the ionospheric effects produced by the SSW are at least two- to threefold weaker than the observed. It is assumed that, in order to achieve a quantitative agreement between simulation and experimental results on the ionospheric effects of the SSW, it is not enough to consider only the dynamics of planetary and tidal waves in the mesosphere. An additional source of the perturbation of the thermosphere and ionosphere during the SSW may be associated with the propagation of internal gravity waves from the lower atmosphere and their dissipation in the thermosphere.

The complex scaling and the stabilization methods are applied to calculating the parameters of the lowest resonance states of He and Li⁺. The results obtained by both methods are in a good agreement with the published data. It is shown that the wave functions constructed using the restricted configuration interaction approximation provide fairly accurate estimates of the resonance parameters. The possibility of using the stabilization method for calculating the phase shift function is also discussed.

The evolution of the electron and atomic and molecular metastable densities and the radiation of the decaying plasma of helium with a 10^–5-fraction of neon additive is experimentally studied. A model of elementary processes in He–Ne plasma is constructed, which describes the formation and destruction of HeNe⁺ and Ne₂⁺ molecular ions and their contribution to the formation of the afterglow spectrum by the electronion recombination. The various criteria influence of neon on the parameters of the decaying plasma are studied. The possibility of determining the amount of neon in helium by measuring the relative intensities of helium molecular bands and neon spectral lines in the afterglow is considered.

The dependences of the initial NO₂ uptake coefficient γ on a methane soot coating at 255 K on the NO₂ concentration (1.3 × 10¹²–3.3 × 10¹³ cm^–3) and time t were studied using a flow reactor with a mobile insert and mass spectrometric recording of gaseous reagents and products: 1/γ(t) = 1/γ₀ + at, where γ₀ and a are the parameters that depend on the NO₂ concentration; γ₀ = γ₀ⁱⁿⁱ/(1 + k_L [NO₂], a= k [NO₂], with the constants γ₀ⁱⁿⁱ = (4.8 ± 2) × 10^–4, K_L = (8.2 ± 3) × 10^–13 cm³, and k = (2.3 ± 0.1) × 10^–10 cm³ s^–1. The elementary parameters that determine the uptake were evaluated on the basis of the Langmuir adsorption model: desorption rate constant k_d = (52 ± 20) s^–1, adsorption heat Q_ad = (38 ± 8) kJ mol^–1, rate constant of the unimolecular heterogeneous conversion of NO₂ into the product k_r = (2.5 ± 1.3) × 10^–2 s^–1, and its activation energy E_a = (19 ± 10) kJ mol^–1. The laboratory data were extrapolated, based on the uptake coefficient, to the limiting tropospheric NO₂ concentrations in remote marine (1 ppb) and polluted industrial regions (40 ppb).