BaTi 2 O 5 (BT2) nanowires were successfully prepared via molten-salt method. The effects of synthesized temperature, dwell time, and molten salt concentration on the formation of BT2 nanowires were studied. X-ray diffraction patterns reveal that the BT2 nanowires crystallize in a monoclinic crystal structure. Neither the longer dwell time nor molten salt concentration has apparent influence on the formation of BT2 phase structure, whereas the synthesized temperature exerts great effect on the morphology of BT2 nanowires. One-dimensional morphology of the BT2 products was only obtained at a narrow temperature window (870-900 °C). At 970 °C, the morphology of BT2 nanowires was destroyed and they are broken into particles, growing as large flat crystals. The BT2 nanowires synthesized at 900 °C exhibit uniform morphology and grow in the [010] direction, which have an average diameter of 780 nm and length of 15 μm. The formation mechanism of BT2 nanowires in the MSS process is proposed. The BT2 nanowires exhibit the single-crystalline characteristics, as proven by high-resolution TEM images and electron diffraction patterns. Quantitative X-ray energy-dispersive spectroscopy analysis shows the BT2 nanowires having homogeneous chemical compositions, and their atomic cation ratio of Ba:Ti is 1:2.16. Dielectric properties of the BT2 nanowires synthesized at 900 °C are measured at room temperature with the frequency ranged from 10 2 to 10 6 Hz. The BT2 nanowires exhibit almost frequency independent dielectric behavior with dielectric constants of 28-31. The dielectric losses remain constant value of ~ 0.02 below 10 5 Hz, and increase up to 0.04 at 10 6 Hz.

The design and development of the complex environment wind engineering simulation software CEWES was carried out, relying on the National Numerical Wind Tunnel Project (NNW). First, based on the characteristics of the physical problem that the software aims to solve, the requirements for the development of complex environment wind engineering simulation software are proposed, and three main modules of the software will be developed: structured grid flow field solver, unstructured grid flow field solvers modeling module of complex terrain and surface. Subsequently, the appropriate mathematical and physical model and numerical solution algorithm are selected for the flow field solver. The CEWES software uses the finite volume method for discretization with second-order accuracy, solves the RANS equations based on the SIMPLE algorithm, uses the k-ε turbulence model to solve the turbulence, and supports large-scale parallelism calculation. Third, the software design was carried out in accordance with the requirements of the CFD solution process and the modular program, focusing on the program architecture, data structure and subroutine interface design, and coding implementation based on the detailed design. Finally, the CEWES software was tested with typical examples. The test results of the calculation examples show that the software calculation results have good accuracy and large-scale parallel computing capabilities, and are suitable for wind engineering simulations in complex terrain environments.

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