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In this work, magnetic In _2 S _3 /ZnFe _2 O _4 nanocomposites were fabricated via a two-step solvothermal process, which In _2 S _3 loading amount on ZnFe _2 O _4 support medium could be controlled by changing reaction mass. Investigation revealed that the photocatalytic activity of In _2 S _3 /ZnFe _2 O _4 nanocomposites was uperior to pure In _2 S _3 and ZnFe _2 O _4 for the degradation of MB driven by visible light. The improved photocatalytic activity may be stemming from the synergy effect of In _2 S _3 and ZnFe _2 O _4 , resulting in the enhanced visible light absorbance and higher separation efficiency of the photo-generated charge carriers. Significantly, this sort of nanocomposites could rapidly be separated through an external magnetic field, and five successive cycle experiments have proved that it was stable and recyclable. Finally, a possible mechanism related to the separation of charge and photocatalytic decomposition of MB was also provided.

BC _5 with both superhard and superconducting properties is expected to have important applications in many fields. In this work, the low-index surface structures and properties of BC _5 have been identified by first-principles calculations. The surface stability decreased in the order of (011) > (010) > (101) > (100) > (110) > (111) > (001). The (011), (101), and (110) surfaces exhibit the strongest surface relaxation, followed by (111), and the (001) surface is the least. A DFT (density functional theory)-based Wulff construction of the equilibrium shape of BC _5 shows that the surface with the largest exposure area is (011), followed by the (101) and (001) surfaces. Electronic analyses show that Pmma phase BC _5 and all considered low-index surfaces exhibit metallic character where the surfaces are even stronger. Larger charge redistribution in the low-index surfaces is found compared with the bulk case.

The transition of trapped-particle orbit topologies has been investigated in quasi-axisymmetric (QA) configurations, such as the Chinese First Quasi-axisymmetric Stellarator (CFQS). It is found that the axisymmetry-breaking phenomenon in QA configurations is of great significance at some specific locations, which could easily induce blocked particles to transit into localized particles. A novel aspect is presented to interpret the transition mechanism of trapped-particle orbit topologies in this paper, i.e., as the amplitudes of non-axisymmetric field increase along the radius direction, the region of large toroidal inhomogeneity is gradually generated, which makes the length of the trapped-particle trajectory substantially short, and hence, may restrict particles to a single helical field period. Meanwhile, at such locations the “pseudo-axisymmetric” field results in coupling of the maximum radial drift and the minimum poloidal drift, which enables the transition of trapped-particle orbit topologies considerably and forms specific loss channels, degrading plasma confinement. These results may shed light on the optimization of QA configurations via avoidance of such coupling with respect to energetic particle confinement. Moreover, this work is also relevant to the generation of inhomogeneity of particle flux deposition on the devertor plates. [ABSTRACT FROM AUTHOR]