Chao Lei

Aluminum–vanadium (Al–V) master alloy is a key raw material for manufacturing high-end alloys, but the internal temperature transient field during its self-propagating high-temperature synthesis (SHS) is nearly impossible to measure in situ. This work develops a numerical simulation framework for Al–V master alloy SHS, featuring a novel temperature–time dual-criteria adaptive moving heat source and a gas–liquid–solid three-phase heat transfer model coupled with temperature-dependent thermophysical properties. The model, implemented in ANSYS Fluent via a customized user-defined function (UDF), is experimentally validated with a maximum temperature error below 7%. Results reveal that higher compact relative density accelerates combustion wave propagation, while increased slagging agent content exerts an inhibitory effect. This study provides a theoretical and quantitative tool for mechanism analysis and industrial process optimization of Al–V master alloy SHS production.

Current-carrying wear is a complex multi-physics coupled phenomenon in electrical contact systems, involving the interaction of mechanical friction, current conduction, and thermal effects, which critically affects the operational reliability of electrical devices. This study presents a systematic investigation of the wear behavior of a QCr0.5 chromium bronze/1080 steel friction pair under current-carrying conditions, integrating experimental measurements with numerical simulations. A multi-physics finite element model was developed within a coupled mechanical–thermal–electrical field framework, incorporating temperature-dependent material properties, definitions of thermal and electrical contact pairs, integration of friction heat and Joule heat, and calculations of friction force and wear rate. Orthogonally designed experiments under varying loads, current intensities, and sliding speeds were conducted to validate the model’s predictive capability for multi-physics coupling. The results demonstrated a maximum error of 17.98% and an average error of 11.07% in wear rate prediction, indicating acceptable accuracy. A detailed analysis of worn surface morphology, combined with simulated wear depth and temperature distributions, systematically identifies the dominant wear mechanisms under different degrees of current influence. The findings reveal that under relatively weak influence of current, the dominant wear mechanisms remain mechanical, including abrasive and adhesive wear. However, under relatively strong influence of current, thermal effects such as Joule heat, friction heat, and potential arc melting lead to material softening, and a transition to electrical–mechanical coupled wear mechanisms. This study introduces a novel multi-physics coupling modeling and numerical simulation framework to investigate current-carrying wear behavior, providing a foundation for the optimization of electrical contact systems.

The intrinsic magnetic topological insulators, Mn(Bi1-xSbx)2Te4, in their spin-aligned strong field configuration have been identified as a Weyl semimetal with single pair of Weyl nodes1-4. A direct consequence of the Weyl state is the layer-dependent Chern number (C) in thin film quantization. Previous reports in MnBi2Te4 thin films revealed the higher C states in the spin alignment by either increasing the film thickness5 or controlling chemical potential into electron doping6-8. A clear picture of the higher Chern states is still missing as the situation is complicated by the emerging of surface band Landau levels (LLs) in magnetic field. Here, we report a tunable layer-dependent of C= 1 state with the Sb substitutions by performing a detailed analysis of the quantization states in Mn(Bi1-xSbx)2Te4 dualgated devices, consistent with the calculations of the bulk Weyl point separations in the compounds. The observed Hall quantization plateaus for our thicker Mn(Bi1-xSbx)2Te4 films under strong magnetic fields can be interpreted from a theory of surface and bulk spin-polarized Landau levels spectrum in thin film magnetic topological insulators. Our results demonstrate that Mn(Bi1-xSbx)2Te4 thin films provide a highly tunable platform for probing the physics of the anomalous Landau quantization that is strongly sensitive to magnetic order.

Surface‐enhanced Raman scattering (SERS) is considered a promising analytical technique for the detection of analytes. Considering the practical SERS detection, it is necessary to develop low‐cost, highly sensitive, and recyclable SERS‐active substrates. Here, a simple and flexible approach is proposed to fabricate a superhydrophobic Ag‐decorated CuO (named as CuO@Ag) nanowire array substrate with analyte‐concentrating and self‐cleaning binary functions for ultrasensitive and recyclable SERS detection. During this process, a superhydrophobic CuO@Ag nanowire array is made via fabrication of a CuO nanowire array by oxidizing and calcinating an ordered porous anodic aluminum oxide template on Cu foil, and following with Ag sputtering deposition on CuO nanowire array. Remarkably, this SERS substrate exhibits ultrasensitive SERS detection ability attributed to superhydrophobic plasmonic metal nanostructured arrays with high analyte‐concentrating ability and excellent photocatalytic capability due to this metal‐semiconductor composite nanostructure. These advantageous properties allow for SERS detection of malachite green with a limit of detection of 6.73 × 10⁻¹³ m and self‐cleaning via photodegradation of adsorbed analytes with visible‐light illumination. Consequently, it achieves recyclable SERS detection. This research demonstrates a simple and flexible approach for fabricating recyclable SERS‐active substrate, which expands the practical SERS applications in chemical and biological analysis, food safety, and healthcare.