No abstract

Based on an integrated array of refractory titanium nitride (TiN), a metasurface perfect absorber (MPA) in the visible-to-near infrared (NIR) band is reported. The systematic and detailed simulation study of the absorption of the MPA is performed with the finite-different time-domain (FDTD) method. Tailoring the structure, the MPA realizes as high an average as 99.6% broadband absorption, ranging from 400 nm to 1500 nm. The broadband perfect absorption can be attributed to localized surface plasmonic resonance (LSPR), excited by the continuous diameter evolution from the apex to the base of the nanocone, and the gap plasmons excited among the nanocones, as well as in the spacer layer at longer wavelengths. Particularly, the coupling of the resonances is essentially behind the broadening of the absorption spectrum. We also evaluated the electric field intensity and polarization-dependence of the nanocone MPA to offer further physical insight into light trapping capability. The MPA shows about 90% average absorption even at an oblique incidence up to 50°, which improves the acceptance capability of light-harvesting system applications. This unique design with the TiN nanocone array/aluminium oxide (Al2O3)/TiN structure shows potential in imminent applications in light trapping and thermophotovoltaics.

The present study provides a deeply analysis of the flow behavior of bubbling fluidized beds with fine particles in two- (2D) and three-dimensional (3D) conditions, and computational fluid dynamics (CFD) simulations of agglomerates fluidization are carried out coupled with the modified agglomerate-force balance model, correspondingly. The experimental results indicate that the fluidized bed can be divided into bottom unfluidized, middle ascending fluidized, and upper descending back-mixing sections. The local solids volume fraction value ranges from 0.11 to 0.30, which depends on the interaction between bubble phase (εs = 0–0.04) and emulsion phase (εs = 0.26–0.30). The wall effect appears to be weakened, and the cohesive particles fluidize more uniformly in 3D fluidized beds. The simulations are in reasonable agreement with the experimental findings. However, at the top region of the bed the predicted solids holdup slightly deviates from experimental measurement. The vector plots of computed agglomerates velocity support the central and wall falling down-both sides rising up flow pattern of solids, two core-annular flows exist in the bed, which can be also observed experimentally.

Recently, 2D electron gases (2DEGs) formed at oxide interfaces are drawing increasing attention as they cause a myriad of intriguing phenomena.