Master’s thesis on “Simulation of processes in physic of solid state using computer programs” consists of an introduction, 3 chapters, conclusions, 22 references of literature, 15 appendixes and 1 compact disc. There are presented 3 tables and 31 pictures in the work as well. The work comprises 56 pages (with appendixes there are 93 pages). The aim of this work is seeking to create demonstrations for lectures in physic of solid state using the mathematical computer system. The first chapter deals with the possibility to use the computer programs in simulation of varied processes and phenomena and put into practice at lectures of solid state physics. The second chapter deals with particular phenomena. There are described the simulations of these phenomena as well. The computer mathematical system MathCAD was used to simulate and analyze the density of band states, Fermi – Dirac and Bolcman functions in the various temperature (5 K < T < 500 K). If we use the state destiny, Fermi – Dirac and Bolcman functions, we will get a distribution of free electrons by values of energy. Dynamic graph of functions is presented, which shows a variation probability of electron to be in E energy state subject to variations of temperature T. There is analyzing dependence of molar heat of solid state against to temperature T. The simulation of Fermi layer and concentration of charge at intrinsic and at impurity semiconductor are composed in this work as well. The using of simulations in lectures... [to full text]

In the present paper, we identify several distributions from Physics and study their applicability to phenomena such as distribution of income, wealth, and expenditure. Firstly, we apply logistic distribution to these data and we find that it fits very well the annual data for the entire income interval including for upper income segment of population. Secondly, we apply Fermi-Dirac distribution to these data. We seek to explain possible correlations and analogies between economic systems and statistical thermodynamics systems. We try to explain their behaviour and properties when we correlate physical variables with macroeconomic aggregates and indicators. Then we draw some analogies between parameters of the Fermi-Dirac distribution and macroeconomic variables. Thirdly, as complex systems are modelled using polynomial distributions, we apply polynomials to the annual sets of data and we find that it fits very well also the entire income interval. Fourthly, we develop a new methodology to approach dynamically the income, wealth, and expenditure distribution similarly with dynamical complex systems. This methodology was applied to different time intervals consisting of consecutive years up to 35 years. Finally, we develop a mathematical model based on a Hamiltonian that maximises utility function applied to Ramsey model using Fermi-Dirac and polynomial utility functions. We find some theoretical connections with time preference theory. We apply these distributions to a large pool of data from countries with different levels of development, using different methods for calculation of income, wealth, and expenditure.