The liquid-gas phase transition is studied in a multi-component nuclear system using a local Skyrme interaction with Coulomb and surface effects. Some features are qualitatively the same as the results of Müller and Serot which uses relativistic mean field without Coulomb and surface effects. Surface tension brings the coexistance binodal surface to lower pressure. The Coulomb interaction makes the binodal surface smaller and cause another pair of binodal points at low pressure and large proton fraction with less protons in liquid phase and more protons in gas phase.

A study of the properties of the symmetry energy of nuclei is presented based on density-functional theory. Calculations for finite nuclei are given so that the study includes isospin-dependent surface symmetry considerations as well as isospin-independent surface effects. Calculations are done at both zero and nonzero temperature. It is shown that the surface symmetry energy term is the most sensitive to the temperature while the bulk energy term is the least sensitive. It is also shown that the temperature-dependence terms are insensitive to the force used and even more insensitive to the existence of neutron skin. Results for a symmetry energy with both volume and surface terms are compared with a symmetry energy with only volume terms along the line of β stability. Differences of several MeV are shown over a good fraction of the total mass range in A. Also given are calculations for the bulk, surface and Coulomb terms.

Various models for fragmentation and partitioning phenomena are developed using methods from permutation groups and combinational analysis. The appearance and properties of power laws in these models are discussed. Several exactly soluble cases are studied. An application to nuclear fragmentation and clusterization is given. A connection with Ewenss approach [Theor. Popul. Biol. 3, 87 (1972); Mathematical Population Genetics (Springer, Berlin, 1979)] to genetic diversity is mentioned. Applications to the social behavior of a vervet monkey troop and to the group behavior of people are given.PACS number(s): 05.40. +j, 02.50.+s

The cluster size distributions in proton-nucleus collisions and in nucleus-nucleus collisions are discussed using a simple exactly soluble model. These distribution can be characterized by a single parameter involving volume, temperature, binding energy, and level density effects. As this parameter varies, the shape of the distribution of cluster size changes. Good agreement is found between a simple theoretical prediction and experiment. PACS number(s): 24.60.k, 25.40.Ve, 25.70.Mn

A canonical ensemble model is used to describe a caloric curve of nuclear liquid-gas phase transition. Allowing a discontinuity in the freeze out density from one spinodal density to another for a given initial temperature, the nuclear liquid-gas phase transition can be described as first order. Averaging over various freeze out densities of all the possible initial temperatures for a given total reaction energy, the first order characteristics of liquid-gas phase transition is smeared out to a smooth transition. Two experiments, one at low beam energy and one at high beam energy show different caloric behaviors and are discussed.Typeset using REVT E X 1