For rigid chiral objects in the low Reynolds number of shear flows, both experimental and theoretical results show that the chiral objects and their enantiomers will migrate in the positive or negative vorticity directions. This phenomenon is widely explored for the possibility of separation of chiral objects in shear flow. Within the simplest twisted "H" molecule model of hydrodynamic interactions of particles, we have calculated the hydrodynamic forces exerted on chiral twisted "H" molecules by shear flows. The chiral parameters that determine their different migration forces in shear flows are identified. The analysis may also be extended to study other complex motions of chiral objects in natural situations and microfluidic cells as well as important chiral-flow interactions, such as the interparticle interactions mediated by fluid flows.

Two different exchange-correlation functionals with van der Waals correction are employed to investigate the electronic properties of 2D MoS TiO 2 2 heterostructure with a special configuration of Moiré pattern. It is found that, for both PBE and HSE06 functional, the new van der Waals heterostructure that consists of monolayer MoS 2 and 2D lepidocrocite-type TiO 2 exhibits a type-II band alignment between the MoS 2 and TiO 2 layers, and the electronic structures of monolayer MoS 2 and 2D TiO 2 are well retained in their respective layers due to a weak interlaminar coupling, which indicates that the new heterostructure may have potential applications in many fields such as photocatalysis, photoelectric devices, solar cells, etc. Furthermore, a novel design scheme based on the new 2D MoS TiO 2 2 van der Waals heterostructure is proposed for a solar cell, and the corresponding power conversion efficiency is estimated to be about 8%.