Adsorption mechanism of coal seam and carbon monoxide gas is studied in microscopic view by using first-principles calculation methods based on quantum mechanics. Due to complexity of coal structure, graphite is used to take place of coal seam for simulation. A model of adsorption of carbon monoxide on graphite is established. Three typical sites with high symmetry on graphite surface are considered. They are top, bridge, and hollow adsorption sites. It shows that bridge site has the highest adsorption energy as carbon monoxide molecule is perpendicular to graphite(001) surface with carbon atom near graphite film.

A two-dimensional Gross-Pitaevskii equation describing Bose-Einstein condensation in an axial symmetry nonharmonic trap is solved.Converged wave functions,chemical potentials,and internal energies in Bose-Einstein condensation are obtained.Ground-state of Bese-Einstein condensation with atomic interaction is investigated.A comparison between harmonic and non-harmonic traps is reported.

We present an improved relaxation algorithm involving rotation of non-spherical particles.In a sphere assembly model,the algorithm simulates random packing of non-spherical particle of any shape as well as particle mixture consisted of particles with different shapes.In the sphere assembly model,particle shape is described with contour of a number of spheres.Contacts between non-spherical particles are treated as contacts of spheres.By introducing torque and rotation of non-spherical particles,the algorithm overcomes self-lock problem,and random close packing is achieved.Packing densities obtained are coincident with numerical and experimental results in literatures.

A hypothesis on electrical field distribution is presented for the physical model of a scanning probe tip with a conical body ending in a spherical apex. Based on the hypothesis, we deduced an analytical model to calculate the electrostatic force acting on the tip and analyzed variation of the electrostatic force with structural parameters of the tip. The simulation results are consistent with those given by numerical methods of equivalent charge distribution (ECD) and by experiments. The hypothesis is proved reasonable according to the work.