Papers by Author: Cong Wang

Abstract: Because traditional displacement form of 3D acoustic perfectly matched layer (PML) absorbing condition needs to split the displacement into three parts, which requires solving a third-order differential equation in time and occupies a large amount of memory. In order to solve the above problems, this paper puts forward an Convolution approximating PML absorbing boundary condition based on the previous works, and discusses the basic construction of the traditional perfectly matched layer absorbing boundary condition and the new arithmetic in detail, then the new method is compared with absorbing condition of low order paraxial approximation and traditional PML, investigating the absorbing effects of 3D acoustic wave’s numerical records.

Abstract: A new cermet film Nb-NbN, deposited on the stainless steel substrate by direct reactive magnetron sputtering, was reported as solar selective absorptive coating. Some fundamental studies on microstructure and optical properties of the Nb-NbN cermet films were carried out by XRD, EDX, SEM and spectrophotometer. A solar absorptivity of 0.94 and a normal emissivity of 0.16 at room temperature were achieved for the coating. Thermal stability was investigated at 350°C and 500°C and it was observed that the absorptivity was changed in a range from 0.92 to 0.94 and the surface emissivity varied firstly from 0.16 to 0.14 and then increasing to 0.19 when the temperature was increased from room temperature to 350°C and up to 500°C.

Abstract: Based on double cermet layer structure, Mo-Al2O3 cermet solar selective coating was prepared on stainless steel substrate. A solar absorptance of 0.92 and normal emittance of 0.19 at room temperature have been achieved. Vacuum annealing treatment was done and its influences on the solar selective performance was discussed. Absorptance changed between 0.90 and 0.92 under the selected annealing temperature range of 350-800°C, and emittance varied from 0.19 to 0.23 when heated at 650°C. The microstructures before and after annealing process at different temperatures were investigated.

Abstract: Sm0.1Ce0.9O1.95 (SDC) films, as promising electrolyte materials, have been successfully prepared on Al2O3 ceramic substrates by RF magnetron sputtering growth. The relationship between sputtering parameters and film microstructure was discussed. Scanning electron microscopy (SEM) and x-ray diffraction (XRD) were used to characterize the morphology and crystal structure of the SDC films. The SEM images show that the crystallinity becomes better and better with the increase of sputtering power from 100W to 300W. X-ray diffraction patterns indicate that the thin SDC electrolyte film on the Al2O3 ceramic substrate grows preferentially along the (111) compact plane with a pure fluorite structure when the RF power reaches 300W. After annealing treatment at 600°C and 800°C, respectively, it can be seen that SDC film becomes denser with few pinholes at the annealing temperature of 800°C. High oxygen ion conductivity (1.46×10-2 Scm-1) of the SDC film was obtained when the RF sputtering power and annealing temperature were 300W and 800°C, respectively.