for the polynomial planar vector fields with a hyperbolic or nilpotent critical point at the origin, the monodromy problem has been solved, but for the strongly degenerate critical points this problem is still open. when the critical point is monodromic, the stability problem or the center- focus problem is an open problem too. in this paper we will consider the polynomial planar vector fields ...

An analytical equation of state has been previously modified by Papari et al. for representing the volumetric properties of molecular fluids. However the performance of that EOS has not been yet well investigated for refrigerant fluids. This study extended that equation to 19 liquid refrigerants to predict their densities at isothermal and saturated states. Two temperature-independent parameter...

Thermophysical properties of fluorine are interesting because of its applications in different areas of technologyand industry. The computations of thermodynamic properties were performed with the GMA equation of stateunder critical conditions. The present work reports calculations of density, volumetric, and thermodynamicproperties of liquid fluorine on extended ranges of pressure and temperat...

The effect of cooling process for the synthesis and the superconductivity properties of Pb-substituted Bi-based materials, has been investigated. The preparation condition for the formation of (2,2,2,3) phase has been examined. The influence of thermal condition of the synthesis and quenching on the critical temperature and the content of 110K phase was investigated. Results of the ac-susceptib...