137 research outputs found
Reaction rate theory with account of the crystal anharmonicity
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
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
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
Absorption of Terahertz Radiation in Ge/Si(001) Heterostructures with Quantum Dots
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
A reflection interferometer with transmission-like characteristics as an element of interferometric gravitational wave detectors
Strengthening of metal crystals subjected to cyclic loading under the simultaneous action of an electric current
Some applications of the generalized Callen-Walton theorem to the calculation of maser noise characteristics
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