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In the framework of the relativistic mean field theory, we investigate K0 condensation along with K− condensation in neutron star matter including the baryon octet. The results show that both K0 and K− condensations can occur well in the core of the maximum mass stars for relatively shallow optical potentials of K in the range of −10MeV ~ −160 MeV. With the increasing optical potential of K, the critical densities of K decrease and the species of baryons appearing in neutron stars become fewer. The main role of K0 condensation is to make the abundances of particles become identical leading to isospin saturated symmetric matter including antikaons, nucleons and hyperons. K− condensation is chiefly responsible for the softening of the corresponding equation of state, which leads to a large reduction in the maximum masses of neutron stars. In the core of massive neutron stars, neutron star matter including rich particle species, such as antikaons, nucleons and hyperons, may exist.

We investigate the dependences of the potential energy surfaces (PES) and the fusion probabilities for some cold fusion reactions leading to super-heavy elements on the nuclear shell effect and pairing energy. It is found that the shell effect plays an important role in the fusion of the super-heavy element while pairing energy's contribution is insignificant. The fusion probabilities and evaporation residue cross sections as functions of the Ge-isotope projectile bombarding Pb-208 are also investigated. It is found that evaporation residue cross sections do not always increase with the increasing neutron number of Ge-isotope.

The global colour model at finite temperature is further extended to study the systems at finite chemical potential. The deconfinement and chiral phase transition at finite chemical potential and at temperature T = 0 K are studied simultaneously. Meanwhile the evolution of the bag constants at finite chemical potential is calculated. The dependence of results on the model parameters are discussed in detail.

A double folding method with simplified Skyreme-type nucleon-nucleon interaction is used to calculate the nuclear interaction potential between two nuclei. The calculation is performed in tip-to-tip orientation of the two nuclei if they are deformed. Based on this methods, the potential energy surfaces, the fusion probabilities and the evaporation residue cross sections for some cold fusion reactions leading to super-heavy elements within di-nuclear system model are evaluated. It is indicated that after the improvement, the exponential decreasing systematics of the fusion probability with increasing charge number of projectile on the Pb based target become better and the evaporation residue cross sections are in better agreement with the experimental data.

The microscopic mechanism of the identical bands in odd–odd nucleus 194Tl and its neighbour odd-A nucleus 193Tl are investigated using the particle-number conserving method with monopole and quadrupole pairing interaction. It is found that the blocking effect plays an important role in the variation of moments of inertia (J(1) and J(2)) with rotational frequency for the superdeformed bands and identical bands. The alignment of 194Tl bands with respect to the 193Tl(1) band used as a reference is also discussed.

The survival probability of the superheavy compound nuclei with Z = 114 is studied with the statistical model. It is found that the survival probability shows drastic odd-even effects. The odd-A compound nuclei have higher survival probability by evaporating three neutrons as compared with their neigbouring even-A compound nuclei.

The global colour model in free space is extended to finite temperature to study the deconfinement and chiral phase transitions at high temperature T and zero chemical potential in the mean field approximation. Both possibilities of coincidence and non-coincidence of the two distinct phase transitions are found when the model parameters are varied in a certain range. The underlying mechanisms of the coincidence and noncoincidence are analysed and discussed. The validity of the T-dependent model propagator as the input is also discussed.

The structure of superheavy nuclei has been studied using the macroscopic-microscopic model. The macroscopic energy was calculated with the continuous medium model in which the energy is expressed as a function of nucleon densities. The deformations and structures of superheavy nuclei were systematically investigated. Calculations reproduce well the available data of experimental α-decay energies and half-lives. The investigation of single-particle levels shows that the shell structure is deformation and isospin dependent. Potential-energy-surface calculations display that superheavy nuclei have in general harder shapes than the nuclei of other mass regions.

Influence of the nuclear deformation on the potential energy surface (PES) in a di-nuclear system is studied in details. It is found that the PES shape changes greatly due to the deformation effect. The top point of the PES could be reduced significantly, which implies that the optimum excitation energy could also be reduced greatly and may enhance the formation probability of the compound nucleus. The dynamical deformation as a function of the reaction time in the reaction process is dramatic. The Z/N ratios of fragments tend to follow that of the compound nucleus during the nucleon exchange process, but to fluctuate.

In the framework of the extended relativistic mean-field theory with hyperons, the properties of neutron star matter have been investigated. It is, found that at a density of four to five times that of nuclear matter saturation density po, a neutron star will become a hyperon star. This transition is strongly influenced by the coupling constants of hyperons to mesons and a different parameter set. For a given parameter set, a minimum transition baryon density exists when the hyperon coupling ratios satisfy x(H sigma) = x(H omega) = x(H rho) = 0.65 or x(H sigma) = x(H omega) = 0.62,x(H rho) = 0.7.

Multi-quasiparticle high-K states in Hf-174 are studied in the framework of the projected shell model. The calculation reproduces well the observed ground-state band as well as most of the two- and four-quasiparticle rotational bands. Some as yet unobserved high-K isomeric states in Hf-174 are predicted. Possible reasons for the existing discrepancies between calculation and experiment are discussed. It is suggested that the projected Shell model may be a useful method for studying multi-quasiparticle high-K isomers and the K-mixing phenomenon in heavy deformed nuclei.

The difference of spectral statistics properties between single-j and two-j shell models has been studied in the frame of the cranking model. The results show that the system becomes more regular when single-j space (i13/2) is replaced by a two-j shell (g7/2 + d5/2), although the basis size of the configuration space is unchanged. However, the degree of chaos of the system changes slightly when configuration space is enlarged by extending the single-j shell (i13/2) to two-j (i13/2 + g9/2) shell.

The discovery of the triaxial superdeformed bands provide a new opportunity to understand the axial symmetry breaking even in highly elongated nuclei. A total of 17 triaxial superdeformed nuclei in the mass A ~ 160 region and 11 in the mass A ~ 80 region are predicted by the three dimensional total routhian surface calculations. A possible way to identify the triaxiality of triaxial superdeformed nuclei is suggested.

Comprehensive evidence of the SU(3) octupole vibration limit in the spdf interacting boson model is found ii, the spectrum, E2 and E1 transition rates, and relative intensities in Gd-158. This is a good example of a rotational nucleus with octupole vibration in the rare-earth region.

We investigate the effects of the nuclear hexadecapole deformations on the interaction potentials between nuclei, the driving potentials and the fusion probabilities for some cold fusion reactions leading to super-heavy elements. It is found that nuclear hexadecapole deformations change significantly the structure of the driving potentials and the fusion probabilities for some reaction channels.

In the framework of the relativistic mean field theory, the effects of the δ meson on protoneutron star matter with hyperons at unite temperature are investigated. In thermal protoneutron star matter, the δ field potential increases with density first and then decreases. Fixing the density, the increase of the temperature suppresses the S field potential. With the inclusion of the δ meson, the threshold densities for hyperons become lower and the abundance of trapped neutrinos decreases. The most important effect of the δ meson is to increase the abundance of hyperons in the inner core range of protoneutron stars. With the rise of the temperature, the density range where the δ meson plays an important role is narrowed and the effects of the δ meson are suppressed. Moreover, the protoneutron star mass and radius are nearly not affected by the δ meson.

We calculate the single-particle resonances in a one-dimensional model potential and isotropic three-dimensional harmonic and Woods-Saxon potentials using the real stabilization method in coordinate space. The results of the real stabilization method are in good agreement with those from the scattering phase shift method and the analytical continuation in the coupling constant method.