[en] First principles calculations of the total energy of CaTe as a function of unit cell volume have been carried out for the NaCl, MnP and CsCl structures on the basis of density functional theory (DFT). All these calculations are performed with the CRYSTAL06 program package. The sequence of high-pressure phases for CaTe transforms from NaCl phase to an intermediate state with a mixture of NaCl and MnP phases and then to the CsCl phase is obtained, which is in good agreement with the previous experimental results. Several structural properties (equilibrium lattice constant, bulk modulus, etc.) of NaCl structure have been calculated, which are also in agreement with the previous experimental results.

[en] Highlights: • Li atoms prefer to be adsorbed at the V-site in both pure monolayer P and SWBPNT. • Compared with the outside, the inside of SWBPNT is a fast diffusion channel for Li. • As the number of Li atoms increases, they still prefer to be adsorbed inside SWBPNT. • The study suggest that SWBPNT can be used in Li-ion batteries as anode base material. Based on first principles calculations, the possibility of zigzag single-walled blue phosphorene nanotube (SWBPNT) as anode materials for high-performance lithium-ion batteries is studied. We calculate the adsorption, diffusion properties and cell voltages of lithium intercalation on the inside and outside of SWBPNT and compare them with those in carbon nanotube (CNT) and single-walled Si nanotube (SWSiNT). The results show that the inside of SWBPNT is a fast diffusion channel of lithium compared with the outside of SWBPNT. By calculating the structure parameters, adsorption energy and charge transfer, we study the adsorption of multiple lithium atoms in SWBPNT. The results show that lithium is easier to diffuse and adsorb inside the tubes, which will help to improve the lithium storage capacity of the system. Therefore, SWBPNT has great potential as anode materials for Li-ion batteries.

[en] Rod-shaped active micro/nano-particles, such as bacterial and bipolar metallic micro/nano-motors, demonstrate novel collective phenomena far from the equilibrium state compared to passive particles. We apply a simulation approach --dissipative particle dynamics (DPD)-- to explore the collectively ordered states of self-propelled rods (SPRs). The SPRs are confined in a finite circular zone and repel each other when two rods touch each other. It is found that for a long enough rods system, the global vortex patterns, dynamic pattern oscillation between hedgehog pattern and vortex pattern, and hedgehog patterns are observed successively with increasing active force F_a. For the vortex pattern, the total interaction energy between the rods U is linear with active force F_a, i.e., U ∼ F_a . While the relation U ∼ F_a² is obtained for the hedgehog structure. It is observed that a new hedgehog pattern with one defect core is created by two ejections of polar cluster in opposite directions from the original hedgehog pattern, and then merges into one through the diffusion of the two aggregates, i.e., the creation and annihilation of topological charges. Graphical abstract:

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