514,512 research outputs found
Investigation of DNA denaturation in Peyrard-Bishop-Dauxois model by molecular dynamics method
The phase transition of duplex into the denaturated
state is studied in the Peyrard-Bishop-Dauxois model by the method of direct
molecular-dynamical modeling. The temperature dependencies of the total energy
and heat capacity of the duplex are calculated. The approach applied can be
used to calculate the statistical properties of the duplexes of any length and
nucleotide composition.Comment: 6 pages, 4 figure
Possibility of Turbulent Crystals
The possibility for the occurrence in crystals of a phenomenon, resembling
turbulence, is discussed. This phenomenon, called {\it heterophase turbulence},
is manifested by the fluctuational appearance inside a crystalline sample of
disordered regions randomly distributed in space. The averaged picture for such
a turbulent solid is exemplified by an exactly solvable lattice-gas model. The
origin of heterophase turbulence is connected with stochastic instability of
quasi-isolated systems.Comment: Latex file, 20 pages, no figure
Minimum energy states of the plasma pinch in standard and Hall magnetohydrodynamics
Axisymmetric relaxed states of a cylindrical plasma column are found
analytically in both standard and Hall magnetohydrodynamics (MHD) by complete
minimization of energy with constraints imposed by invariants inherent in
corresponding models. It is shown that the relaxed state in Hall MHD is the
force-free magnetic field with uniform axial flow and/or rigid azimuthal
rotation. The relaxed states in standard MHD are more complex due to the
coupling between velocity and magnetic field. Application of these states for
reversed-field pinches (RFP) is discussed
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