183 research outputs found

    Reaction rate theory with account of the crystal anharmonicity

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    Reaction rate theory in solids is modified taking into account intrinsic localized modes or discrete breathers (DBs) that can appear in crystals with sufficient anharmonicity resulting in violation of Arrhenius law. Large amplitude oscillations of atoms about their equilibrium positions in the lattice cause local potentials of alternating sign, which are described in terms of time-periodic modulations of the potential barriers for chemical reactions taking place in the vicinity of DBs. The reaction rate averaged over large macroscopic volumes and times including a lot of DBs is increased by a factor that depends on the DB statistics. The breather statistics in thermal equilibrium and in thermal spikes in solids under irradiation with swift particles is considered, and the corresponding reaction rate amplification factors are derived.Comment: 17 pages, 12 figure

    Atmospheric bistatic communication channels with scattering. Part 2. Field Experiments in 2013

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    Results of field experiments on the influence of atmospheric conditions and some instrumental characteristics on the quality of information transfer in a bistatic optoelectronic communication system (OECS) operating in the visible wavelengths range are considered. The length of the atmospheric channel reached 17 km. Radiation of a copper bromide vapor laser with a wavelength of 510.6 nm was used as a signal source. It is shown that bistatic or over-the-horizon OECSs can operate both under the conditions of a cloudy and cloud-free atmosphere. Average values and standard deviations of communication errors were estimated under different atmospheric-optical conditions when some characteristics of individual instrumentation units varied

    Between-strain differences in hypothermic response in mice after intranasal administration of PtO nanoparticles

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    Air pollution by particulate matter (PM) has been associated with cardiopulmonary morbidity and mortality in many recent epidemiological studies. It has been shown that transition metal compounds, well- known toxic components of PM, are able to induce hypothermia following whole-body inhalation exposure. Low temperature appears to protect tissue against toxic effects of PM metal compounds in vivo and in vitro. To study the role of soluble and insoluble irritants in the induction of the hypothermic response, we analyz­ed the decrease in mouse body temperature (Δtbody) after intranasal administration of PtO nanoparticles or a K2[PtCl 4] solution. Between-strain differences in Δtbody after intranasal administration of the irritants were evaluated using 6 inbred (BALB/cJ, C57BL/6J, AKR/OlaHsd, DBA/2JRccHsd, C3H/HeNHsd, and SJL/J) and 2 outbred mouse strains (SCID and CD1). BALB/cJ and SCID mice showed the most pronounced effect of intranasal admini­stration of the xenobiotic on tbody. Thus, tbody was signi­ficantly lower after nasal administration the PtO nano­particles than after administration of the K2[PtCl 4] solution. To study the mechanism of this decrease, we compar­ed the respective values for Δtbody following intra­nasal, intravenous and peroral administration of PtO nanoparticles in Balb/c mice. Neither intravenous nor peroral administration had any effect on mouse body temperature. This fact together with data on the dynamics of the decrease in mouse body temperature following intranasal administration of PtO nanoparticles (max Δtbody ~ 80–100 min) allowed us to assume that this process is under nervous regulation. The correlation found between our data and some well-known phenotypic characteristics (phenome.jax.org) of the mouse strains used confirms this hypothesis

    Optimal control problems with maximum functional

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76172/1/AIAA-20777-321.pd

    Absorption of Terahertz Radiation in Ge/Si(001) Heterostructures with Quantum Dots

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    The terahertz spectra of the dynamic conductivity and radiation absorption coefficient in germanium-silicon heterostructures with arrays of Ge hut clusters (quantum dots) have been measured for the first time in the frequency range of 0.3-1.2 THz at room temperature. It has been found that the effective dynamic conductivity and effective radiation absorption coefficient in the heterostructure due to the presence of germanium quantum dots in it are much larger than the respective quantities of both the bulk Ge single crystal and Ge/Si(001) without arrays of quantum dots. The possible microscopic mechanisms of the detected increase in the absorption in arrays of quantum dots have been discussed.Comment: 9 pages, 4 figures; typos correcte

    The Energy Strategy of Russia until 2020 and real life. What is next?

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