In large eddy simulations (LES), a flat ground model and rough wedge ground models with different wedge heights were adopted to investigate near-surface wind field characteristics under condition of time-varying upstream inflows. In both flat ground model and rough wedge ground models, simulated results show that there is downdraft in peak period of gusty wind and updraft in valley period, respectively. Intensity of downdraft/updraft flows are related to ground roughness in upwind areas and amplitude of inflows. It follows that wind velocity and direction in atmospheric boundary layer always change over time in time-varying upstream inflows, which enhances transportation of mass and energy in actual atmospheric boundary layer.

Geometric structure of W_mB_n(m+n≤7) clusters are optimized by using density functional theory at B3LYP/LANL2DZ level. For ground state configurations, average binding energies, second order differential energies, energy gaps and WIB bond orders are analyzed. It shows that ground state structures of WB_n clusters are flat structures; as m≥2 and m+n≥4, all clusters are cube structure except W₃B cluster. Stability of clusters is getting better and better as W atoms increase. The bonding strength of W-W is significantly higher than those of W-B and B-B key. W atom plays a leading role in stability of clusters. Stability of W₂B₂ and W₃B cluster is the best.

Possible equilibrium geometries of W_mC_n clusters are optimized by using density functional theory at B3LYP/LANL2DZ level.For ground-state structures,average binding energy,second difference in energy,HOMO-LOMO gaps and the Wiberg bond index are analyzed.With increasing tungsten atoms,structures of clusters transform from linear into planar,and then become three-dimensional structures.All spin multiplicity is not more than 5.Hybridization of carbon atoms enhanced stability of the clusters,but reduced chemical activity.And Wiberg of W-C is much stronger than that of W-W and C-C,so it is easier to form W-C bond in W_mC_n clusters.