Railway Engineering Science (铁道工程科学)•2026•DOI: 10.1007/s40534-025-00419-y
This study quantifies the degradation of fatigue crack growth (FCG) resistance in high-speed train bogie frame materials after long-term service. Full-scale frame fatigue tests, multiaxial FCG experiments, and finite element simulations were integrated to determine equivalent crack loading conditions. Digital image correlation captured surface displacement fields for stress intensity factor calculation. Comparative testing of as-welded (AW) and base metal (BM) regions before and after service revealed substantial reductions in remaining useful life: 70.54% for AW and 22.31% for BM. Crack-tip strain responses increased by more than twofold in AW and 1.44 times in BM after service, indicating diminished crack growth resistance. Microscopic fracture surface analysis showed more secondary cracks, unstable crack paths, and blurred fatigue striations in post-service materials, particularly in the AW region. Phased array ultrasonic testing detected no macroscopic defects, yet microstructural deterioration was evident. These findings establish a quantitative link between service-induced damage and fatigue performance degradation, supporting region-specific residual life assessment strategies for bogie frames. The experimental protocol, grounded in actual service loading spectra, improves the accuracy of remaining useful life prediction and provides a reliable basis for maintenance decision-making in high-speed rail operations.
Journal of Semiconductors (半导体学报 - 中国科学院半导体研究所)•2026•DOI: 10.1088/1674-4926/25060021
The escalating demand for ultra-high-resolution flexible displays necessitates thin-film transistors (TFTs) with carrier mobility exceeding 30 cm2·V−1·s−1 on compliant substrates. Conventional indium-gallium-zinc-oxide (IGZO) TFTs, despite commercial maturity, are constrained by field-effect mobility (μFE) of approximately 10 cm2·V−1·s−1, limiting drive current and pixel density. This work reports the first demonstration of flexible indium tin oxide (ITO) TFTs fabricated through a mass-production compatible process utilizing SiO2 gate dielectric. The devices achieve an average μFE of 39.1 cm2·V−1·s−1, a threshold voltage (Vth) variation of +0.45 V under a 7 mm bending radius, and a mobility reduction of only −5.5% under the same mechanical stress. Dynamic bending tests up to 13,000 cycles reveal no significant degradation in μFE or Vth. Electrical stress tests under ±5 V bias confirm ΔVth constrained within 1 V. The excellent large-scale uniformity is attributed to the ultra-flat surface and low coefficient of thermal expansion (CTE) of the polyimide (PI) substrate, combined with laser lift-off (LLO) processing. These results establish ITO as a viable channel material for ultra-high-resolution foldable displays and wearable electronics, though the absence of a passivation layer remains a limitation for long-term stability.
Nano-Micro Letters•2026•DOI: 10.1007/s40820-025-01993-w
With the escalating demand for safe, sustainable, and high-performance energy storage systems, hydrogel electrolytes have emerged as promising alternatives to conventional liquid electrolytes in zinc-ion batteries. By integrating the high ionic conductivity of liquid electrolytes with the mechanical robustness of solid frameworks, hydrogel electrolytes offer distinct advantages in suppressing zinc dendrite formation, enhancing interfacial stability, and enabling reliable operation under extreme environmental conditions. This review systematically summarizes the fundamental characteristics and design criteria of hydrogel electrolytes, including mechanical flexibility, ionic transport capabilities, and environmental adaptability. It further explores various compositional design strategies involving natural polymers, synthetic polymers, and composite systems, as well as the incorporation of electrolyte salts and functional additives. In addition, recent advances in functional optimization, such as anti-freezing properties, self-healing abilities, thermal responsiveness, and biocompatibility, are comprehensively discussed. Finally, the review outlines the current challenges and proposes potential directions for future research.
Nano-Micro Letters•2025•DOI: 10.1007/s40820-025-01702-7
Emerging two-dimensional (2D) semiconductors are among the most promising materials for ultra-scaled transistors due to their intrinsic atomic-level thickness. As the stacking process advances, the complexity and cost of nanosheet field-effect transistors (NSFETs) and complementary FET (CFET) continue to rise. The 1 nm technology node is going to be based on Si-CFET process according to international roadmap for devices and systems (IRDS) (2022, https://irds.ieee.org/), but not publicly confirmed, indicating that more possibilities still exist. The miniaturization advantage of 2D semiconductors motivates us to explore their potential for reducing process costs while matching the performance of next-generation nodes in terms of area, power consumption and speed. In this study, a comprehensive framework is built. A set of MoS2 NSFETs were designed and fabricated to extract the key parameters and performances. And then for benchmarking, the sizes of 2D-NSFET are scaled to a extent that both of the Si-CFET and 2D-NSFET have the same average device footprint. Under these conditions, the frequency of ultra-scaled 2D-NSFET is found to improve by 36% at a fixed power consumption. This work verifies the feasibility of replacing silicon-based CFETs of 1 nm node with 2D-NSFETs and proposes a 2D technology solution for 1 nm nodes, i.e., "2D eq 1 nm" nodes. At the same time, thanks to the lower characteristic length of 2D semiconductors, the miniaturized 2D-NSFET achieves a 28% frequency increase at a fixed power consumption. Further, developing a standard cell library, these devices obtain a similar trend in 16-bit RISC-V CPUs. This work quantifies and highlights the advantages of 2D semiconductors in advanced nodes, offering new possibilities for the application of 2D semiconductors in high-speed and low-power integrated circuits.
Nano-Micro Letters•2025•DOI: 10.1007/s40820-025-01655-x
The past decade has witnessed the rapid increasement in power conversion efficiency of perovskite solar cells (PSCs). However, serious ion migration hampers their operational stability. Although dopants composed of varied cations and anions are introduced into perovskite to suppress ion migration, the impact of cations or anions is not individually explored, which hinders the evaluation of different cations and further application of doping strategy. Here we report that a special group of sulfonic anions (like CF3SO3−) successfully introduce alkaline earth ions (like Ca2+) into perovskite lattice compared to its halide counterparts. Furthermore, with effective crystallization regulation and defect passivation of sulfonic anions, perovskite with Ca(CF3SO3)2 shows reduced PbI2 residue and metallic Pb0 defects; thereby, corresponding PSCs show an enhanced PCE of 24.95%. Finally by comparing the properties of perovskite with Ca(CF3SO3)2 and FACF3SO3, we found that doped Ca2+ significantly suppressed halide migration with an activation energy of 1.246 eV which accounts for the improved operational stability of Ca(CF3SO3)2-doped PSCs, while no obvious impact of Ca2+ on trap density is observed. Combining the benefits of cations and anions, this study presents an effective method to decouple the effects of cations and anions and fabricate efficient and stable PSCs.
Nano-Micro Letters•2025•DOI: 10.1007/s40820-025-01654-y
Transition metal carbides, known as MXenes, particularly Ti3C2Tx, have been extensively explored as promising materials for electrochemical reactions. However, transition metal carbonitride MXenes with high nitrogen content for electrochemical reactions are rarely reported. In this work, transition metal carbonitride MXenes incorporated with Pt-based electrocatalysts, ranging from single atoms to sub-nanometer dimensions, are explored for hydrogen evolution reaction (HER). The fabricated Pt clusters/MXene catalyst exhibits superior HER performance compared to the single-atom-incorporated MXene and commercial Pt/C catalyst in both acidic and alkaline electrolytes. The optimized sample shows low overpotentials of 28, 65, and 154 mV at current densities of 10, 100, and 500 mA cm−2, a small Tafel slope of 29 mV dec−1, a high mass activity of 1203 mA mgPt−1 and an excellent turnover frequency of 6.1 s−1 in the acidic electrolyte. Density functional theory calculations indicate that this high performance can be attributed to the enhanced active sites, increased surface functional groups, faster charge transfer dynamics, and stronger electronic interaction between Pt and MXene, resulting in optimized hydrogen absorption/desorption toward better HER. This work demonstrates that MXenes with a high content of nitrogen may be promising candidates for various catalytic reactions by incorporating single atoms or clusters.
Int. Journal of Mining Science and Technology (采矿与安全工程)•2025•DOI: 10.1016/j.ijmst.2025.06.009
Borehole pressure relief helps prevent rock bursts. However, this may change the physical and mechanical properties of the surrounding rock, affect the variation of the plastic zone of the roadway, and lead to the failure of roadway support, thus threatening the safety of the roadway. In this paper, the variable angle shear test of drilled specimens under the action of static and dynamic loads is used to study the evolution of mechanical parameters of the specimens and their influence on the plastic zone of the surrounding rock. The shear strength decreases linearly with the increase of drilling diameter. With the increase of pre-static load level and dynamic load amplitude, the cohesion first increases and then decreases, and the internal friction angle decreases. Moreover, the shear failure surface changes from rough to smooth. The reasons include that the static load enhances the tooth cutting effect and the repeated friction of cracks caused by the dynamic load. Borehole pressure relief leads to an increase in the radius of the plastic zone of the surrounding rock following a quadratic function. The research results of this paper provide a theoretical basis for designing drilling unloading parameters and supporting parameters for rock burst roadways.
Int. Journal of Mining Science and Technology (采矿与安全工程)•2025•DOI: 10.1016/j.ijmst.2025.07.012
Gob-side entry retaining (GER) is widely applied in China. Nevertheless, the stability mechanism of the GER with coal pillar-backfill body (CPBB) under dynamic overburden load remains unexplored. A voussoir beam structure (VBS) model is established to analyze roof structure stability during panel advancement, introducing a VBS stability criterion. Reducing block B length l and immediate roof damage variable D, and increasing coal pillar width xc, lowers the GER structure instability risk. Reducing l and the GER width w leads to a CPBB system stability upswing. A UDEC model was established to systematically reveal how the l, backfill body width xb, and strength affect the stability and coupling performance of the CPPB system by monitoring the crack damage DC. Simulation results indicate that at l=14 m, xb=2.0 m, water-cement ratio 1.5:1, the coal pillar and backfill body have similar DC but maintain stability, resulting in CPPB system coupling degree Ϗ, better. A novel GER method supported by the CPBB was implemented on-site. Monitoring results indicated that the coal pillar peak stresses were 19.17 MPa (ahead), 16.14 MPa (behind), and the backfill body peak stress was 12.27 MPa (maximum). The floor heave was 380 mm, with a 103 mm backfill body rib.
Int. Journal of Minerals, Metallurgy and Materials (矿物冶金与材料学报)•2025•DOI: 10.1007/s12613-025-3244-1
The effect of thermal degradation on the welded hybrid joints of metal and polymer composites is insufficient, which seriously inhibits the engineering applications of the joints. In this study, robust hybrid joints of metal and polymer composites were fabricated by the combination of friction lap welding (FLW) and laser surface treatment for investigating the effect of accelerated aging on the joint properties. Results showed that the FLW hybrid joints without laser surface treatment exhibited 91% reduction in the tensile shear force (TSF) after 7 days of accelerated aging tests. In contrast, the FLW hybrid joints with suitable laser surface treatment exhibited only 26% reduction in TSF even after 35 days of accelerated aging tests. Fractures of the tensile specimens occurred across the composite plates rather than along the joint interface. The enhanced reliability of the hybrid joints was mainly attributed to (1) the formation of micro-mechanical interlocking between the polymer composites and aluminum alloy plate, and (2) the modification of the stress distribution along the joint interface.
Chinese Journal of Mechanical Engineering•2025•DOI: 10.1186/s10033-025-01229-3
The exploration of titanium alloy applications in railway transportation aims to meet the newly emerged demand for vehicles that are lighter and more efficient. This research focuses on the potential of these materials to concurrently reduce vehicle weight and enhance efficiency, sustainability, and safety. Challenges faced include high production and processing costs, durability issues in harsh railway environments, and environmental impacts associated with alloy production. Research findings indicate that innovative alloy design and advanced processing techniques, such as powder metallurgy, additive manufacturing, and surface treatment, significantly improve the applicability of titanium alloys in railway applications. These methods substantially increase energy efficiency and safety. Additionally, advancements in environmentally sustainable practices in the production of titanium alloys address ecological concerns. As research progresses, the study and development of low-cost, high-performance titanium alloys highlight the need for more efficient and environmentally friendly manufacturing processes. Exploring new alloy compositions and applying emerging technologies in processing and manufacturing are key areas for future research. These advancements are expected to enhance the role of titanium alloys in revolutionizing railway transportation, aligning with global trends towards sustainability and performance improvement. This research underscores the significant potential contribution of titanium alloys to future efficient and eco-friendly rail travel.
Journal of Central South University•2025•DOI: 10.1007/s11771-025-6127-8
In this study, the effect of Cu2+ on the cassiterite and calcite flotation using octanohydroxamic acid (OHA) as collector was investigated through flotation tests, solution reaction tests and calculation, zeta potential measurements, XPS analysis and residual reagent concentration measurements. Results indicated that Cu2+ played an activation role on cassiterite flotation but a depression role on calcite flotation. The copper cations were adsorbed on the cassiterite surface by forming a Cu―O bond, and the pre-adsorbed copper cations and the OHA-Cu complexes promoted the adsorption of OHA on the cassiterite surface. Thus, cassiterite flotation was activated. The dissolved HCO3− in the calcite pulp underwent a double hydrolysis reaction with copper cations (Cu2+, CuOH+, Cu2(OH)2 2+ and Cu3(OH)4 2+) to form CuCO3. Some copper cations were adsorbed on the calcite surface as well, but some adsorbed Cu2+ on the calcite surface was desorbed by bonding with OHA, and most of OHA was consumed by Cu2+, basic copper carbonate and copper hydroxide. The residual OHA in the pulp was not sufficient for flotation, so calcite flotation was depressed. Finally, a model of the reaction mechanism of Cu2+ and OHA on the cassiterite and calcite surfaces was established.
Int. Journal of Minerals, Metallurgy and Materials (矿物冶金与材料学报)•2025•DOI: 10.1007/s12613-025-3179-6
The comprehensive status of blast furnaces was one of the most important factors affecting their economy, quality, and longevity. The blast furnace comprehensive status had the nature of “black box,” and it was “unpredictable.” In this study, a blast furnace comprehensive status score and prediction method based on a cascade system and a combined model were proposed to address this issue. A dual cascade evaluation system was developed by integrating subjective and objective weighting methods. The analytic hierarchy process, coefficient of variation, entropy weight method, and impart combinatorial games were jointly employed to determine the optimal weight distribution across indicators. Categorized statuses (raw material, gas flow, furnace body, furnace cylinder, and iron–slag) were evaluated. Based on the five categories of the status data, the second cascade was applied to upgrade the quantitative evaluation of the comprehensive status. The weights of the different categories were 0.22, 0.15, 0.22, 0.21, and 0.20, respectively. According to the data analysis, the results of the comprehensive status score closely matched the on-site production logs. Based on the blast furnace smelting period, the maximal information coefficient method was applied to the 100 parameters that were most relevant to the comprehensive status. A combined prediction model for a comprehensive status score was designed using bidirectional long short-term memory (BiLSTM) and categorical boosting (CatBoost). The test results indicated that the combined model reduced the mean absolute error by an average of 0.275 and increased the hit rate by an average of 5.65 percentage points compared to BiLSTM or CatBoost alone. When the error range was ±2.5, the combined model predicted a hit rate of 91.66% for the next hour’s comprehensive status score, and its high accuracy was deemed satisfactory for the field. SHapley Additive exPlanations (SHAP) and regression fitting were applied to analyze the linear quantitative relationship between the key variables and the comprehensive status score. When the furnace bottom center temperature was increased by 10°C, the comprehensive status score increased by 0.44. This method contributes to a more precise management and control of the comprehensive status of the blast furnace on-site.
Int. Journal of Mining Science and Technology (采矿与安全工程)•2024•DOI: 10.1016/j.ijmst.2024.12.006
The storage of solid waste in Bayan Obo has resulted in significant resource wastage and environmental concerns. In this study, an efficient process was developed to recover iron and rare earth elements (REEs) from this waste by processes of hydrogen-based mineral phase transformation (HMPT), magnetic separation, and flotation. Under optimal HMPT conditions (525 °C, 12.5 min, and 30% H2 concentration), an iron concentrate with a TFe grade of 64.09% and a recovery of 95.33% was obtained. The magnetic properties of the solid waste were greatly enhanced by HMPT, allowing the effective magnetic separation of iron minerals. Further optimization of the flotation process resulted in a REEs concentrate with a rare earth oxide (REO) grade of 65%–70% and a REEs recovery of 60%–65%. Hematite was reduced to magnetite during HMPT, and bastnaesite was decomposed to REEs oxides and fluorides, and the particle structure was significantly destroyed. However, changes in monazite, fluorite, and barite were minimal.