Railway Engineering Science (铁道工程科学)•2026•DOI: 10.1007/s40534-025-00415-2
Wheelset tread defects in subway locomotives present critical safety hazards, yet manual inspection remains prevalent, suffering from inefficiency and human error. This study proposes an enhanced YOLOv5-based detection algorithm tailored for subway wheelset tread defects. A multi-head self-attention module is integrated to capture long-range dependencies within global feature maps, improving small-target detection. A weighted bidirectional feature pyramid network (BiFPN) enables balanced multi-scale feature fusion and efficient cross-scale integration. To mitigate limited labeled data and annotation inaccuracies, a novel loss function, W-MPDIoU, is introduced to accelerate convergence. Experimental validation using real defect data and simulated experimental data yields an average detection accuracy of 99.1%, a 4.29% improvement over the original YOLOv5, with a detection speed of 15 ms per image. The model also outperforms YOLOv12 in convergence speed, detection accuracy, and inference speed. Despite these gains, limitations persist in defect variety and dataset size, necessitating further refinement for broader generalization. The proposed method enables real-time tread defect detection, enhancing safety and operational efficiency in urban rail transit maintenance.
New Carbon Materials (新型炭材料)•2025•DOI: 10.1016/S1872-5805(NCM2024-39-04-04)
A transformation of naphthalene-based coalescenced mesophase pitch (NMP) to mesophase microbeads was achieved by heating a mixture of NMP and fullerene (C60). This is different from the conventional process of the liquid-phase carbonization of isotropic pitch to the emergence of carbon microbeads in the matrix and finally their growth to form a 100% anisotropic bulk mesophase, but rather a reverse transformation. The effects of C60 loading and reaction temperature on the morphological transformation of mesophase were investigated by polarizing optical and scanning electron microscopies. The physical changes in the NMP induced by C60 were characterized by thermogravimetric analysis, Fourier transform infrared spectroscopy, X-ray diffractometry and Raman spectroscopy. The results show that the coalesced NMP can be converted to a spherical type at 300–320 °C with the addition of 5% C60, and the size of the mesophase microbeads increases with increasing temperature. Furthermore, a model is established to explain the unique induction effect of C60 in the transformation process. This work makes the morphological transformation of MP controllable, and provides a new idea for the understanding and research of mesophase pitch.
New Carbon Materials (新型炭材料)•2025•DOI: 10.1016/S1872-5805(NCM2024-39-03-06)
In recent years, zinc-ion hybrid capacitors (ZIHCs) have attracted increasing attention due to their environmental friendliness and excellent electrochemical properties. However, their performance is mainly limited by the electrochemical performance of the cathode, so it is necessary to develop an advanced cathode material. N, B co-doped sodium alginate-based porous carbon (NBSPC) was prepared by one-step co-carbonization using sodium alginate as the matrix and NH4B5O8 as the N and B source. This N, B co-doping strategy improves the pore structure of the carbon materials and increases the number of surface functional groups, greatly improving the capacitive behavior of the raw materials and thus improving their electrochemical performance. When used as the cathode in ZIHCs, the NBSPC had an excellent rate performance (85.4 mA h g−1 even at ultra-high current density of 40 A g−1) and good cycling stability (15 000 cycles at 20 A g−1 with a capacity retention rate of 94.5%).
Int. Journal of Mining Science and Technology (采矿与安全工程)•2025•DOI: 10.1016/j.ijmst.2025.02.001
Lunar core samples are the key materials for accurately assessing and developing lunar resources. However, the difficulty of maintaining borehole stability in the lunar coring process limits the depth of lunar coring. Here, a strategy of using a reinforcement fluid that undergoes a phase transition spontaneously in a vacuum environment to reinforce the borehole is proposed. Based on this strategy, a reinforcement liquid suitable for a wide temperature range and a high vacuum environment was developed. A feasibility study on reinforcing the borehole with the reinforcement liquid was carried out, and it is found that the cohesion of the simulated lunar soil can be increased from 2 to 800 kPa after using the reinforcement liquid. Further, a series of coring experiments are conducted using a self-developed high vacuum (vacuum degree of 5 Pa) and low-temperature (between −30 and 50 ℃) simulation platform. It is confirmed that the high-boiling-point reinforcement liquid pre-placed in the drill pipe can be released spontaneously during the drilling process and finally complete the reinforcement of the borehole. The reinforcement effect of the borehole is better when the solute concentration is between 0.15 and 0.25 g/mL.
Chinese Journal of Mechanical Engineering•2025•DOI: 10.1186/s10033-025-01328-1
During the grinding train operation process, the grinding force between the grinding wheel and the rail is critical in ensuring the grinding quality and efficiency. The coupling vibration among the frame, the grinding wheels, and the wheelsets will seriously affect the stability of the grinding force. In this paper, the coupled mechanical model of the grinding wheel/rail is established based on the contact mechanics theory, which is embedded as a sub-model into the dynamic model of the multi-rigid buggy. The interaction among the frame, the grinding wheels and the wheelsets is analysed by setting the convex irregularity on the rail. The grinding effect is evaluated in combination with the subway’s long wave corrugation grinding conditions. The results show that when the grinding buggy passes the convex irregularity, the vibration excited by the wheelset system has a significant impact on the dynamic behavior of the grinding wheels. The vibration of the grinding wheel is mainly transmitted between the grinding wheel and the frame, less affecting the wheelset. For the long wave corrugation of the subway, the grinding effect of the grinding wheel has a certain correlation with the phase angle of the wheelset through the corrugation. The research results provide an important reference for the setting of the grinding pattern.