4,211 research outputs found
The Friedberg-Lee model at finite temperature and density
The Friedberg-Lee model is studied at finite temperature and density. By
using the finite temperature field theory, the effective potential of the
Friedberg-Lee model and the bag constant and have been
calculated at different temperatures and densities. It is shown that there is a
critical temperature when
and a critical chemical potential for fixing
the temperature at . We also calculate the soliton solutions
of the Friedberg-Lee model at finite temperature and density. It turns out that
when (or ), there is a bag constant (or
) and the soliton solutions are stable. However, when (or
) the bag constant (or ) and there is no soliton solution anymore, therefore, the
confinement of quarks disappears quickly.Comment: 12 pages, 11 figures; version accepted for publication in Phys. Rev.
2-(4-Hydroxyphenoxy)propanoic acid
In the title compound, C9H10O4, the carboxyl group is oriented at a dihedral angle of 84.6 (3)° with respect to the benzene ring. In the crystal, molecules are linked via O—H⋯O hydrogen bonds
Robust Average Formation Tracking for Multi-Agent Systems With Multiple Leaders
In this paper, the formation tracking problem of the multi-agent system under disturbances and unmodeled uncertainties has been studied. An identifier-based robust control algorithm using the neighboring relative information has been proposed to ensure the followers to maintain a given, and time-varying formation and track the average state of the leaders at the same time. Some sufficient conditions for the second-order multi-agent system with multiple leaders in the presence of disturbances and unmodeled uncertainties have been proposed based on the graph theory and the Lyapunov method. Numerical simulations are provided to testify the validity of the algorithm
2-Chloropyridine-3-carboxamide
In the crystal structure of the title compound, C6H5ClN2O, the dihedral angle between the pyridine ring and the carboxamine group is 63.88 (8)°. Intermolecular N—H⋯N and N—H⋯O hydrogen bonds link the molecules into a two-dimensional network
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