The linear magnetoresistance (MR) effect is an interesting topic due to its potential applications. In topological insulator Bi2Se3, this effect has been reported to be dominated by the carrier mobility (μ) and hence has a classical origin. Here, we study the magnetotransport properties of Bi2Se3 thin films and observe the linear MR effect, which cannot be attributed to the quantum model. Unexpectedly, the linear MR does not show the linear dependence on μ, in conflict with the reported results. However, we find that the observed linear MR is dominated by the inverse disorder parameter 1/kFl, where kF and l are the Fermi wave vector and the mean free path, respectively. This suggests that its origin is also classical and that no μ-dominated linear MR effect is observed which may be due to the very small μ values in our samples.

Quantum transport phenomenon such as quantum Hall effect usually appears up at cryogenic temperature. Here, we observe a room-temperature quantum transport phenomenon in ZnO-based two-dimensional systems. We successfully fabricate Zn1–x Mg x O/ZnO heterostructures by using magnetron sputtering with a low growth temperature which makes it feasible to obtain flexible heterostructures. Electrical transport properties of these heterostructures are studied. A parabolic negative magnetoresistance is clearly observed in a wide temperature range, which can be accurately described by the weak localization theory. By analyzing the temperature dependence of the dephasing length, it is found that the electron–electron scattering combined with two-dimensional electron–phonon scattering dominates the dephasing process for electrons. Importantly, the observed negative magnetoresistance persists up to 300 K. This indicates that room-temperature weak localization effect appears up, which can be attributed to weak electron–phonon scattering and small electron mobility. The present work provides a reference for realizing room-temperature quantum effect which is beneficial to develop quantum-interference devices.

B4C/Al composites of different boron carbide contenting were prepared by the liquid mixing method and hot-rolled to 3mm. Microstructure and mechanical properties of the rolled composite were analyzed after the stress relieving heat treatment. Results showed that: the distribution of boron carbide particles was uniform, and only a few particles appeared fractured. With Ti addition, a reaction product layer was fabricated surrounding B4C particles, which acted as a diffusion barrier to separate B4C particles from liquid aluminum to protect them. With the mass fraction of the B4C particles increasing, it can improve the tensile strength but degrade the plasticity of the composites. The fracture surface of composites showed both ductile and brittle fracture characteristics and when the mass fraction of the B4C particles increased the ductile fracture feature decreased.

In this work, the microstructure evolution of as-cast NAB under different electropulsing parameters were studied. The microstructure of the electropulsing treatment (EPT) sample was characterized by mircohardness test and optical microscopy. The results show that compared with heat treatment, when the peak current density reaches 5.84×108A/m2 (no significant change in the structure when the peak current density is lower), the β' phase region undergo phase transition in a shorter time. When the peak current density reaches 7.25×108A/m2, the sample is significantly affected by the Joule heating effect, and the κⅢ and κⅣ phases are successively dissolved to form Widmanstätten α structure. As the β' phase increases and the Widmanstätten α structure forms, the hardness value of the microstructure increases by 80%.

The present work is focused on electroless coating of copper nanolayer onto boron carbide (B4C) particle surfaces by using copper activation method. The B4C particles used are approximately 18.25μm in average size. B4C particle surfaces were washed by acetone and activated through copper activation method. In the electroless coating bath, copper sulfate, EDTA-2Na and seignette salt, hydrazine hydrate were used as the copper catalytic centers source, complexing agent and reducing agent respectively. The structure and morphology of the coating layers were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). XRD and SEM observations show that B4C particle surfaces were successfully coated by a homogeneous and continuous copper layer.