4,696 research outputs found
The bifurcation phenomena in the resistive state of the narrow superconducting channels
We have investigated the properties of the resistive state of the narrow
superconducting channel of the length L/\xi=10.88 on the basis of the
time-dependent Ginzburg-Landau model. We have demonstrated that the bifurcation
points of the time-dependent Ginzburg-Landau equations cause a number of
singularities of the current-voltage characteristic of the channel. We have
analytically estimated the averaged voltage and the period of the oscillating
solution for the relatively small currents. We have also found the range of
currents where the system possesses the chaotic behavior
Hydrogen transport in superionic system Rb3H(SeO4)2: a revised cooperative migration mechanism
We performed density functional studies of electronic properties and
mechanisms of hydrogen transport in Rb3H(SeO4)2 crystal which represents
technologically promising class M3H(XO4)2 of proton conductors (M=Rb,Cs, NH4;
X=S,Se). The electronic structure calculations show a decisive role of lattice
dynamics in the process of proton migration. In the obtained revised mechanism
of proton transport, the strong displacements of the vertex oxygens play a key
role in the establishing the continuous hydrogen transport and in the achieving
low activation energies of proton conduction which is in contrast to the
standard two-stage Grotthuss mechanism of proton transport. Consequently, any
realistic model description of proton transport should inevitably involve the
interactions with the sublattice of the XO4 groups.Comment: 11 pages, 11 figures, to appear in Physical Review
Simulation of Time-Resolved Vibronic Spectra and the possibility of analyzing molecules with similar apectral properties
The possibility of using time-resolved vibronic spectroscopy for spectral
analysis of mixtures of chemical compounds with similar optical properties,
when traditional methods are inefficient, is demonstrated by using the method
of computer simulation. The analysis is carried out by the example of molecules
of a series of polyenes (butadiene, hexatraene, octatetraene, decapentaene, and
decatetraene), their various cis- and trans-rotational isomers, and
phenyl-substituted polyenes. Ranges of relative concentrations of molecules
similar in their spectral properties, where reliable interpretation of
time-resolved spectra of mixtures and both qualitative and quantitative
analyses are possible, are determined. The use of computer simulation methods
for oprimizing full-scale experiments in femtosecond spectroscopy is shown to
hold much promise
Extracts from Problems of Air Law, a collection of works of the Section of air law of the Aviakhim Society of the USSR and Aviakhim RSFSR
The difficulties of developing a body of international law to govern air travel is discussed. A summary of literature and agreements is presented as well as a brief history. Air space over the poles and the legality of methods of claiming territory in the polar regions is discussed
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