By using the tight-binding model and nonequilibrium Green's function method (NEGF), we study the band structures and transport properties of a silicene nanoribbon with a line defect where a bulk energy gap is opened due to the sublattice symmetry breaking. The flat subband bends downwards or upwards due to the effect of the line defect. The spin-orbit coupling induces the quantum spin Hall states. Especially, the energy band depends on the distance between the line defect and the edge of the nanoribbon. The effects of the on-site energies on the band spectra of the two defect configurations are different. There always exists one band gap for different on-site energies for the defect configuration of case 1. However, a gapless state and a band gap can be modulated by changing the on-site energy, the sublattice potential, and spin-orbit couplings for the defect configuration of case 2. Accordingly, the variation trends of the conductance including zero conductance can be well understood in terms of the combined effect of the sublattice potential, the on-site energy, and spin-orbit couplings on the band structures. Thus it is easy and effective to modulate the transport property of the silicene nanoribbon with the defect configuration of case 2 by utilizing the sublattice potential, the on-site energy, and spin-orbit couplings. This study is of great significance for the fabrication and the modulation of the transport property of silicene-based devices.

The mechanism and kinetics of the elemental Hg oxidation in flue gas by ozone injection are investigated in detail by using quantum chemistry, kinetic simulation and experimental research. The reaction processes, activation energies and kinetic parameters are calculated and analyzed by quantum chemistry. From the comparison of activation energies, the Hg⁰ oxidation ability of oxidizing radicals is that: NO₃>O₃>NO₂. The calculated results are in good agreement with literature experimental results. The calculated kinetic parameters are employed for kinetic simulation. The results of kinetic simulation are in good agreement with the experimental results. Results show that, the Hg⁰ oxidization increases linearly when the mole ratio of O₃/NO becomes larger or the reaction temperature becomes higher. The reaction Hg+NO₃ = NO₂+HgO is the key elemental reaction and the concentration of NO₃ is the most important factor for affecting Hg⁰ oxidation.