空气斜槽浓相煤粉输送的实验研究

在一个长7 m的空气斜槽内进行浓相输送煤粉的实验研究.实验结果表明,随着空气表观速度增加,煤粉饱和输送量先增加,随后达到稳定,约为0.25kg/s.槽倾角低于5°时,煤粉不流动.倾角在5°～7°内,煤粉的饱和输送量和最大固气质量比随角度变化不明显,但随倾角增大,处于最大固气比下的工作空气速度范围增大.输送槽高度对煤粉的...     

High-order harmonic generations in tilted Weyl semimetals

We investigate high-order harmonic generations (HHGs) under comparison of Weyl cones in two types. Due to the hyperboloidal electron pocket structure, strong noncentrosymmetrical generations in high orders are observed around a single type-II Weyl point, especially at zero frequency. Such a remarkable DC signal is proved to have attributions from the intraband transition after spectral decomposition. Under weak pulse electric field, the linear optical response of a non-tilted Weyl cone is consistent with the Kubo theory. With extensive numerical simulations, we conclude that the non-zero chemical potential can enhance the even-order generations, from the slightly tilted system to the over-tilted systems. In consideration of dynamical symmetries, type-I and type-II Weyl cones also show different selective responses under the circularly polarized light. Finally, using a more realistic model containing two pairs of Weyl points, we demonstrate that paired Weyl points with opposite chirality can suppress the overall even-order generations.