With first-principles plane-wave ultrasoft pseudopotential method based on density functional(DFT) system, we analyze properties of optical gas sensor materials anatase TiO₂(101) surfaces with NO₂ adsorption. Cu and Cr atoms are easily doped on TiO₂(101) surface. Cu and Cr doped TiO₂(101) surfaces could absorbed NO₂ molecules steadily. After adsorption, material optical properties changed obviously. Cu doped TiO₂(101) surfaces have the highest adsorption energy and the shortest distance between surface and molecule. Analyzing charge density difference and charge population we found that charge transfer occurs between NO₂ molecule and material surface. Electron transfer number is as follows:Cu-doped surface > Cr-doped surface > Undoped surface. Comparing absorption and reflection spectra we found that Cu-doped surface optical properties changed obviously. Redox capacity between surfaces and molecules decided optical gas sensing propertiess. Cu and Cr has 4s valence electron structure which could reduce materials oxygen vacancies oxidative properties. For oxidizing gases, 4s electron could increase surfaces and molecules redox effect. Cu 4s electron is more active. It indicates that Cu doped TiO₂ is a good optical gas sensor material for oxidizing gases.

Molecular dynamic (MD) simulations were performed to simulate stretching process of graphene containing defect in which AIREBO potential is used to describe interactions of atoms. We investigated defect location effect on tensile behavior of graphene. It shows that defect location has different influence on fracture process of graphene. Distance to boundary and arrangement of defect have great effect on mechanical stability of graphene. It suggests that mechanical property of graphene can be improved through location control of defect.

In order to identify key nodes in network effectively, a comprehensive index of node importance recognition which considers local and global characteristics of network is proposed. Nodes in weighted standard test system IEEE39 and IEEE118 are sorted according to importance based on this index. Ranking results are compared with those based on betweenness centrality method and point weight method. Meanwhile these important methods of node recognition are compared using structure-based network efficiency analysis and dynamics-based loss-of-synchronization diffusion time and synchronization capability. It shows that ranking of node importance based on comprehensive index is more reasonable, which is superior to node recognition method based on betweenness centrality and point weight.

Heating of magnetized plasmas by low-frequency Alfvén waves propagating along background magnetic field is studied with test particle simulation.It shows that ions in perpendicular and parallel directions of the background magnetic field are heated significantly.In a stage of non-resonance heating,perpendicular heating is more significant than parallel heating,and anisotropic temperature comes into being.In a stage of stochastic heating,perpendicular and parallel temperatures of ions finally reach saturation and convergence.In heating process,the maximum kinetic temperature of ions is dependent on the ratio of magnetic field energy density and plasma density,which has no relevance with Alfvön-wave frequency and amplitude.Ions are significantly accelerated in parallel direction.and attained a bulk speed that is roughly equal to phase velocity of Alfvén waves.

Electronic transport of a two-probe system consisting of Au (111) electrodes and two base pairs sandwiched between Au (111) contacts is investigated with density functional theory combined with non-equilibrium Green's function method.It shows that conductance of base pairs is sensitive to distance between electrodes and oscillates.At a fixed gap between electrodes,transverse transport of base pairs under low bias is calculated and is compared with base pairs with a silver ion.It shows that conductive capability of G-C decreases and that of A-T increases as silver ions are combined with base pairs.

Based on an Input-Output algorithm,a precise design method of DOE is proposed adapting fast Fourier transform algorithm.Numerical simulation indicates that this method improves beam shaping effectively.With same diffractive efficiency,interpolation iterative arithmetic reduces PV by 14% and RMS by 4%.The algorithm provides better initial phases of DOE for simulating annealing optimization than primitive Input-Output algorithm.

An automatic Nonet-Cartesian grid method is presented together with Euler solutions of flows around complicated geometries. Grids are generated automatically by the recursive subdivision of a single cell into nine subcells for isotropic Nonet-Cartesian grids and into three subcells independently in each direction for anisotropic Nonet-Cartesian grids, encompassing the entire flow domain. The grid generation method is applied here to steady inviscid shocked flow computation. Results using this approach demonstrate that this method provides a simple and accurate procedure for solving flow problems with shock waves.