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Information × Registration Number 0218U000974, 0116U005640 , R & D reports Title Dissipative processes in nucleus-nucleus collisions with large dynamical excitations popup.stage_title Head Kolomietz Vladimir Mikhailovich, Registration Date 05-03-2018 Organization Sceintific Center "Inststute for nuclear reaseach National Academy of sciences Ukraine popup.description2 Boltzman-Vlasov kinetic equation, which takes into account the self-consistent mean field, has been solved for calculations of the shear viscosity of the nucleon gas with van der Waals equation of state. Expressions for the shear viscosity in the first-order approximation of the perturbation expansion within the frequent collision regime by using the hard-core sphere model have been derived. It is shown that the shear viscosity depends on the particle number density through the attractive mean-field interaction, in contrast to the known Chapman-Enskog expression. The generalized viscosity is in agreement with the results of previous calculations with good accuracy for zero mean-field interaction limit and decreases with increasing particle density. The ratio of the shear viscosity to the entropy density in the temperature-density plane above the critical point (about 15 MeV) but below a temperature for creations of new particles in nucleus-nucleus collisions (smaller 40 MeV) was obtained. For typical values of the mass and size of the nucleon, we showed that this ratio has a minimum in the temperature-density plane near the normal density of the nuclear matter (0.16 fm-3) and much smaller that that found within the Chapman-Enskog approximation. Evolution of the volume and isospin instability in nuclear matter at extremal temperatures and particle densities has been studied. It has been shown that this evolution is essentially influenced by the existence of the anomal dispersion, dynamical Fermi-surface distortion and dissipative processes. The temperature and density dependences of the incompressibility K and isotopic energy symmetry have been found. The increament of the growing volume instability depends on the temperature of the system and multipolarity of the density perturbation. The temperature and the Fermi-surface perturbation effects determine mainly the properties of the instability: Nuclear fission and multifragmentation. The properties of the nuclear-matter droplet with accounting for the surface diffuse layer and Coulomb interaction have been studied. It has been proposed and used in practical calculations the direct variational method to obtain the total energy and equations of state of the nuclear-matter droplet of a finite size. The influence of the diffuse surface layer on the formations of the deformation energy for extremal excitations of the nuclear-matter droplet and its fission barrier has been calculated with taking into account the Coulomb interaction and isotopic asymmetry. Product Description popup.authors Кривенко-Еметов Ярослав Дмитрович Лук'янов Сергій Володимирович Магнер Олександр Григорович Радіонов Сергій Вікторович Санжур Андрій Ігорович Федоткін Сергій Миколайович popup.nrat_date 2020-04-02 Close