Surface Technology (表面技术)•2026•DOI: 10.16490/j.cnki.issn.1001-3660.2026.10.008
Traditional continuous galvanizing of steel strips faces escalating energy consumption, wettability limitations on advanced high-strength steels, and hydrogen embrittlement risks. This study establishes and experimentally validates a coupled Hertz-Knudsen evaporation and choked-flow jet deposition model for a continuous thermal jet physical vapor deposition (PVD) process. Using SPCC cold-rolled steel strips at a substrate temperature of 160 °C, zinc vapor generated in a crucible (913–943 K) is transported through a vapor distribution box and accelerated to supersonic velocity (Mach > 1) via a Laval nozzle. Theoretical coating thicknesses (9.49–15.42 µm) agree with measured values (9.22 ± 0.2 to 13.2 ± 0.6 µm), confirming model validity. Compared with non-continuous vacuum evaporation, the continuous thermal jet-PVD process increases deposition rate from 5 nm/s to 1.32 × 10^4 nm/s (2,600-fold), coating density from 86.3% to 97.4%, gloss from 3.7 GU to 30 GU (8-fold), and adhesion critical load from 24,316 mN to 34,618 mN (42% increase). Corrosion current density decreases from 66.4 µA/cm² to 27.8 µA/cm² (58% reduction), and neutral salt spray red-rust time extends from 48 h to 72 h. Microstructural analysis reveals a transition from hexagonal crystallites with random orientation to a microcrystalline structure with a dominant (102) texture. This dense (102)-oriented coating acts as a physical barrier against chloride ion penetration and promotes a protective corrosion product layer, offering a high-speed, clean alternative to conventional hot-dip and electro-galvanizing.
Surface Technology (表面技术)•2026•DOI: 10.16490/j.cnki.issn.1001-3660.2026.09.001
High-speed dry cutting of hardened steel imposes severe oxidative and diffusion wear on AlCrN/TiSiN-coated tools, limiting service life. This study introduces a multilayer composite plus pre-oxidation strategy: an AlCrN/TiSiN coating deposited by arc ion plating is subjected to controlled pre-oxidation, forming an in-situ AlCrTiSiON oxide barrier. Static oxidation, high-temperature tribological tests, and dry milling of hardened 45 steel evaluate performance. After 800 °C oxidation, the AlCrN/TiSiN coating develops porous TiO/TiO2 and o-SiO2 phases, while the multilayer coating retains sharp protective oxide peaks and strong fcc-TiN/fcc-CrN reflections. Hardness peaks at 49.64 GPa after 600 °C oxidation, with H/E = 0.102 and H3/E*2 = 0.426 GPa. Critical load reaches 85 N after 700 °C oxidation. At 700 °C friction, wear rate minimizes at 2.28×10−10 mm3/(N·mm); at 800 °C, friction coefficient drops to 0.63. In dry milling, the multilayer tool achieves a wear band of only 60.66 μm after 90 min, and a cutting life 13.83 times that of uncoated and 3.46 times that of AlCrN/TiSiN-coated tools. Cutting temperature is reduced by 68 °C at 120 min compared to the AlCrN/TiSiN coating. The pre-oxidized oxide layer suppresses oxygen inward diffusion and heat conduction, enhancing structural stability and tool longevity.
Opto-Electronic Advances (光电进展)•2026•DOI: 10.29026/oea.2026.250267
Scene-level passive 3D imaging under natural conditions remains a critical unmet need, as established techniques such as structured light, LiDAR, and active stereo rely on controlled illumination and scanning, limiting their applicability to large, dynamic outdoor environments. Passive polarization 3D imaging offers inherent advantages for long-range, high-precision reconstruction but is fundamentally impeded by two obstacles: the π ambiguity of the azimuth component of surface normals and the discontinuity of multiple targets within a scene. This study introduces a scene-level passive polarization 3D imaging method that integrates binocular stereo vision with polarization cues. The reconstruction of discontinuous targets is formulated as a minimization problem, where pixel-level normal directions from polarization and absolute scale information from binocular stereo serve as mutual constraints for iterative optimization. This framework resolves the discontinuity challenge and recovers true depth. A scale normalization strategy globally aligns multi-view measurement data, eliminating inter-frame scale inconsistencies that hinder dynamic reconstruction. Multi-frame point cloud fusion yields the final scene-level 3D structure. Experimental validation on natural field scenes demonstrates robust, wide-scene, high-accuracy passive video reconstructions with centimeter-level precision. This passive polarization stereo approach represents a significant advancement in scene-level 3D imaging, with potential applications in autonomous navigation, environmental monitoring, and cultural heritage documentation.
Journal of Advanced Ceramics•2026•DOI: 10.26599/JAC.2026.9221340
Protonic ceramic fuel cells (PCFCs) offer efficient intermediate-temperature energy conversion but are constrained by the trade-off between insufficient electrode activity and limited operational durability. This work develops a Zn/Yb B-site codoping strategy combined with temperature-induced nanoparticle exsolution to construct a triple-conducting cathode. Cation-driven charge modulation enhances ionic diffusion and electronic conduction, while the exsolved secondary BaCoO3−δ phase increases active site density, optimizes interfacial charge transfer, and promotes oxygen reduction reaction (ORR) kinetics. Zn/Yb codoping redistributes local charge density, weakens metal–oxygen bonds, and reduces oxygen vacancy formation energy, promoting oxygen vacancy generation. The increased oxygen vacancy concentration facilitates surface oxygen activation and lattice hydration, enhancing oxygen-ion and proton transport. Enhanced d–p orbital hybridization improves electronic conductivity and accelerates charge transfer kinetics. Optimized alkaline–earth sites suppress carbonate formation, imparting excellent CO2 tolerance. The optimized cathode delivers a peak power density of 0.99 W·cm−2 at 600 °C and stable operation over 100 h, with a polarization resistance of 0.110 Ω·cm2 under 20% H2O-air. This work provides a novel strategy for optimizing activity, conductivity, and stability in PCFC cathodes.
China Foundry•2026•DOI: 10.1007/s41230-026-5206-2
A novel cast stainless steel featuring a multiphase microstructure and a nominal composition of Fe-13.5Cr-2.6Si-6.9Ni-1.1Cu-1.1Mn-1.0Mo-0.35Al-0.025C (wt.%) was investigated. Following solution treatment at 1,050 °C and water quenching, the specimens were subjected to further tempering at 570 °C, 610 °C, and 650 °C to explore the effects of critical tempering on microstructure, mechanical properties, and corrosion resistance. Various characterization techniques were employed to examine the phase distribution within the microstructure, with particular attention given to the content and morphology of reverted austenite. Tensile and corrosion tests were carried out to evaluate the performance of the specimens. The results reveal that critical tempering significantly enhances the mechanical properties, with the specimen tempered at 610 °C achieving the highest product of strength and elongation (PSE=23.6 GPa·%), whereas corrosion resistance deteriorates with increasing tempering temperature. Calculations of the martensite start temperature (Ms) and stacking fault energy (γSFE) for the reversed austenite in different specimens indicate that the stability of reversed austenite strongly influences mechanical behavior through the TRIP and TWIP effects. However, tempering-induced Cr segregation at ferrite/martensite interfaces and the formation of Cr-depleted zones become more pronounced at higher tempering temperatures, leading to a degradation in corrosion resistance. Furthermore, multiphase coordinated deformation improves the strength-ductility balance, while corrosion tends to initiate at chemically inhomogeneous phase boundaries.
Nano-Micro Letters•2026•DOI: 10.1007/s40820-025-02012-8
Owing to the exceptional optoelectronic properties, metal halide perovskites have emerged as leading semiconductor materials for next-generation display technologies, providing perovskite light-emitting diodes (PeLEDs) great potential for high-quality color displays with a wide color gamut and pure color emission. Although laboratory-scale PeLEDs have achieved near-theoretical efficiencies, challenges such as achieving uniform large-area films, improving material stability, and enhancing patterning precision remain barriers to commercialization. This review presents a systematic analysis of scalable manufacturing and precision patterning strategies for PeLEDs, focusing on their applications in large-area lighting and full-color displays. Fabrication methods are categorized into film deposition techniques (spin-coating, blade-coating, and thermal evaporation) and patterning strategies, including top-down (photolithography, laser/e-beam lithography, and nanoimprinting) and bottom-up (patterned crystal growth, inkjet printing, and electrohydrodynamic jet printing) approaches. In this review, we discuss the advantages and limitations of each strategy, highlight current challenges, and outlook possible pathways towards scalable, high-performance PeLEDs for advanced optoelectronic applications.
Journal of Central South University•2026•DOI: 10.1007/s11771-026-6228-z
The Western Dongting Lake area, a biodiversity hotspot under traditional farming, has long suffered heavy metal pollution. In this study, the concentrations of As, Cd, Cr, Hg, and Pb in agricultural soils were determined and ecological risks were evaluated using both the hazard quotient(HQ) model and the probabilistic ecological risk assessment(PERA) model. The results showed that HQ suggested slight or negligible risks, whereas PERA indicated consistently high and unacceptable risks. This discrepancy arose because HQ criteria are derived from human health thresholds and provide only deterministic estimates, whereas PERA incorporates species-specific predicted no-effect concentration(PNEC), environmental variability, and uncertainty, thereby providing more precise and site-specific risk assessments and assigning probabilities. By applying a tiered PERA model, our study highlights its novelty and superiority in ecological risk characterization, providing critical guidance for soil management and ecological protection in contaminated farmlands.
Nano-Micro Letters•2025•DOI: 10.1007/s40820-025-01946-3
Photo-assisted lithium–sulfur batteries (PALSBs) offer an eco-friendly solution to address the issue of sluggish reaction kinetics of conventional LSBs. However, designing an efficient photoelectrode for practical implementation remains a significant challenge. Herein, we construct a free-standing polymer–inorganic hybrid photoelectrode with a direct Z-scheme heterostructure to develop high-efficiency PALSBs. Specifically, polypyrrole (PPy) is in situ vapor-phase polymerized on the surface of N-doped TiO2 nanorods supported on carbon cloth (N-TiO2/CC), thereby forming a well-defined p–n heterojunction. This architecture efficiently facilitates the carrier separation of photo-generated electron–hole pairs and significantly enhances carrier transport by creating a built-in electric field. Thus, the PPy@N-TiO2/CC can simultaneously act as a photocatalyst and an electrocatalyst to accelerate the reduction and evolution of sulfur, enabling ultrafast sulfur redox dynamics, as convincingly validated by both theoretical simulations and experimental results. Consequently, the PPy@N-TiO2/CC PALSB achieves a high discharge capacity of 1653 mAh g−1, reaching 98.7% of the theoretical value. Furthermore, 5 h of photo-charging without external voltage enables the PALSB to deliver a discharge capacity of 333 mAh g−1, achieving dual-mode energy harvesting capabilities. This work successfully integrates solar energy conversion and storage within a rechargeable battery system, providing a promising strategy for sustainable energy storage technologies.
Nano-Micro Letters•2025•DOI: 10.1007/s40820-025-01783-4
Disrupting the symmetric electron distribution of porphyrin-like Fe single-atom catalysts has been considered as an effective way to harvest high intrinsic activity. Understanding the catalytic performance governed by geometric microstrains is highly desirable for further optimization of such efficient sites. Here, we decipher the crucial role of local microstrain in boosting intrinsic activity and durability of asymmetric Fe single-atom catalysts (Fe–N3S1) by replacing one N atom with S atom. The high-curvature hollow carbon nanosphere substrate introduces 1.3% local compressive strain to Fe–N bonds and 1.5% tensile strain to Fe–S bonds, downshifting the d-band center and accelerating the kinetics of *OH reduction. Consequently, highly curved Fe–N3S1 sites anchored on hollow carbon nanosphere (FeNS-HNS-20) exhibit negligible current loss, a high half-wave potential of 0.922 V vs. RHE and turnover frequency of 6.2 e−1 s−1 site−1, which are 53 mV more positive and 1.7 times that of flat Fe–N–S counterpart, respectively. More importantly, multiple operando spectroscopies monitored the dynamic optimization of strained Fe–N3S1 sites into Fe–N3 sites, further mitigating the overadsorption of *OH intermediates. This work not only sheds new light on local microstrain-induced catalytic enhancement, but also provides a plausible direction for optimizing efficient asymmetric sites via geometric configurations.
Nano-Micro Letters•2025•DOI: 10.1007/s40820-025-01791-4
Conductive hydrogels have garnered widespread attention as a versatile class of flexible electronics. Despite considerable advancements, current methodologies struggle to reconcile the fundamental trade-off between high conductivity and effective absorption-dominated electromagnetic interference (EMI) shielding, as dictated by classical impedance matching theory. This study addresses these limitations by introducing a novel synthesis of aramid nanofiber/MXene-reinforced polyelectrolyte hydrogels. Leveraging the unique properties of polyelectrolytes, this innovative approach enhances ionic conductivity and exploits the hydration effect of hydrophilic polar groups to induce the formation of intermediate water. This critical innovation facilitates polarization relaxation and rearrangement in response to electromagnetic fields, thereby significantly enhancing the EMI shielding effectiveness of hydrogels. The electromagnetic wave attenuation capacity of these hydrogels was thoroughly evaluated across both X-band and terahertz band frequencies, with further investigation into the impact of varying water content states—hydrated, dried, and frozen—on their electromagnetic properties. Moreover, the hydrogels exhibited promising capabilities beyond mere EMI shielding; they also served effectively as strain sensors for monitoring human motions, indicating their potential applicability in wearable electronics. This work provides a new approach to designing multifunctional hydrogels, advancing the integration of flexible, multifunctional materials in modern electronics, with potential applications in both EMI shielding and wearable technology.
Int. Journal of Mining Science and Technology (采矿与安全工程)•2025•DOI: 10.1016/j.ijmst.2025.08.016
Chalcopyrite is often intergrown with talc, which, after grinding, forms ultrafine particles (<10 μm) that readily coat chalcopyrite surfaces, hindering flotation and causing significant losses in tailings. This study evaluates polyvinyl acetate (PVAc), a thermoplastic polymer, as a selective flocculant to enhance reverse flotation separation of chalcopyrite from ultrafine talc. Flotation tests showed that at a PVAc dosage of 40 mg/L, talc can be effectively and selectively removed, enabling efficient separation. Laser particle size analysis and scanning electron microscopy-energy dispersive spectrometry (SEM-EDS) confirmed that PVAc promotes selective talc aggregation without affecting chalcopyrite. X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations revealed that hydrogen bonding between PVAc ester groups and surface hydroxyls on talc drives the flocculation, while chalcopyrite lacks suitable binding sites. PVAc adsorption also enhances talc hydrophobicity. Furthermore, particle-bubble coverage angle measurements and extended Derjaguin-Landau-Verwey-Overbeek (DLVO) theory theoretical calculations demonstrated that PVAc-induced flocculation increases attractive interactions between talc and bubbles, shifting the total interaction energy from repulsive to attractive and promoting bubble-particle attachment. This study clarifies the selective adsorption and flocculation mechanisms of PVAc and reveals the coupling of flocculation and flotation of ultrafine talc from a particle-bubble capture perspective, while expanding the potential of ester-based polymers for ultrafine mineral recovery.
New Carbon Materials (新型炭材料)•2025•DOI: 10.1016/S1872-5805(NCM2024-39-06-07)
Carbon with its high electrical conductivity, excellent chemical stability, and structure ability is the most promising anode material for sodium and potassium ion batteries. We developed a defect-rich porous carbon framework (DRPCF) built with N/O-co-doped mesoporous nanosheets and containing many defects using porous g-C3N4 (PCN) and dopamine (DA) as raw materials. We prepared samples with PCN/DA mass ratios of 1/1, 2/1 and 3/1 and found that the one with a mass ratio of 2/1 and a carbonization temperature of 700 °C in an Ar atmosphere (DRPCF-2/1-700), had a large specific surface area with an enormous pore volume and a large number of N/O heteroatom active defect sites. Because of this, it had the best pseudocapacitive sodium and potassium ion storage performance. A half battery of Na//DRPCF-2/1-700 maintained a capacity of 328.2 mAh g−1 after being cycled at 1 A g−1 for 900 cycles, and a half battery of K//DRPC-2/1-700 maintained a capacity of 321.5 mAh g−1 after being cycled at 1 A g−1 for 1200 cycles. The rate capability and cycling stability achieved by DRPCF-2/1-700 outperforms most reported carbon materials. Finally, ex-situ Raman spectroscopy analysis result confirms that the filling and removing of K+ and Na+ from the electrochemically active defects are responsible for the high capacity, superior rate and cycling performance of the DRPCF-2/1-700 sample.
New Carbon Materials (新型炭材料)•2025•DOI: 10.1016/S1872-5805(NCM2024-39-05-13)
As by-products of petroleum refining, heavy oils are characterized by a high carbon content, low cost and great variability, making them competitive precursors for the anodes of potassium ion batteries (PIBs). However, the relationship between heavy oil composition and potassium storage performance remains unclear. Using heavy oils containing distinct chemical groups as the carbon source, namely fluid catalytic cracking slurry (FCCS), petroleum asphalt (PA) and deoiled asphalt (DOA), three carbon nanosheets (CNS) were prepared through a molten salt method, and used as the anodes for PIBs. The composition of the heavy oil determines the lamellar thicknesses, sp3-C/sp2-C ratio and defect concentration, thereby affecting the potassium storage performance. The high content of aromatic hydrocarbons and moderate amount of heavy component moieties in FCCS produce carbon nanosheets (CNS-FCCS) that have a smaller layer thickness, larger interlayer spacing (0.372 nm), and increased number of folds than in CNS derived from the other three precursors. These features give it faster charge/ion transfer, more potassium storage sites and better reaction kinetics. CNS-FCCS has a remarkable K+ storage capacity (248.7 mAh g−1 after 100 cycles at 0.1 A g−1), long cycle lifespan (190.8 mAh g−1 after 800 cycles at 1.0 A g−1) and excellent rate capability, ranking it among the best materials for this application. This work sheds light on the influence of heavy oil composition on carbon structure and electrochemical performance, and provides guidance for the design and development of advanced heavy oil-derived carbon electrodes for PIBs.
New Carbon Materials (新型炭材料)•2025•DOI: 10.1016/S1872-5805(NCM2024-39-05-06)
The advent of the 5G era has stimulated the rapid development of high power electronics with dense integration. Three-dimensional (3D) thermally conductive networks, possessing high thermal and electrical conductivities and many different structures, are regarded as key materials to improve the performance of electronic devices. We provide a critical overview of carbon-based 3D thermally conductive networks, emphasizing their preparation-structure-property relationships and their applications in different scenarios. A detailed discussion of the microscopic principles of thermal conductivity is provided, which is crucial for increasing it. This is followed by an in-depth account of the construction of 3D networks using different carbon materials, such as graphene, carbon foam, and carbon nanotubes. Techniques for the assembly of two-dimensional graphene into 3D networks and their effects on thermal conductivity are emphasized. Finally, the existing challenges and future prospects for 3D carbon-based thermally conductive networks are discussed.
New Carbon Materials (新型炭材料)•2025•DOI: 10.1016/S1872-5805(NCM2024-39-05-02)
Lithium-ion batteries (LIBs) are used in electric vehicles and portable smart devices, but lithium resources are dwindling and there is an increasing demand which has to be catered for. Sodium ion batteries (SIBs), which are less costly, are a promising replacement for LIBs because of the abundant natural reserves of sodium. The anode of a SIB is a necessary component of the battery but is less understood than the cathode. This review outlines the development of various types of anodes, including carbon-based, metallic and organic, which operate using different reaction mechanisms such as intercalation, alloying and conversion, and considers their challenges and prospects. Strategies for modifying their structures by doping and coating, and also modifying the solid electrolyte interface are discussed. In addition, this review also discusses the challenges encountered by the anode of SIBs and the solutions.
New Carbon Materials (新型炭材料)•2025•DOI: 10.1016/S1872-5805(NCM2024-39-03-03)
Graphene is widely used in photodetection because of its high carrier mobility and wide spectral absorption range. However, its high dark current caused by its low light absorption severely limits its performance. Molybdenum dihalide (MoX2, X=S, Se and Te) has a high absorption coefficient, which can compensate for the high dark current in graphene-based photodetectors and result in outstanding photoelectronic properties of those based on a graphene/MoX2 van der Waals heterostructure (vdWH). In this review, we firstly review working principles, performance indicators, and structures of photodetectors. After that, the significance of graphene/MoX2 vdWH photodetectors is highlighted from the fundamental perspective. Preparation methodologies and performance enhancement strategies of graphene/MoX2 vdWH photodetectors are correspondingly summarized. In the end, we highlight the current challenges and future directions of the graphene/MoX2 vdWH photodetectors. This review will guide the design of high-performance vdWH photodetectors.
New Carbon Materials (新型炭材料)•2025•DOI: 10.1016/S1872-5805(NCM2026-41-02-05)
Due to the inherent limited dielectric loss of carbon materials, their attenuation ability and impedance matching are often unsatisfactory. To overcome these problems, hierarchical structures and combined microwave loss mechanisms have attracted considerable attention in the development of high performance microwave absorbers. In this work, biomass cattail was used as a sustainable precursor to synthesize nitrogen-doped carbon nanotube arrays decorated with Fe3C nanoparticles by chemical vapor deposition. The resulting cattail-derived carbon-based tubular composites (Fe3C@NCNTs/CMTs) feature a unique Fe3C-coated, nitrogen-doped carbon nanotube structure. The influence of crystallinity, tuned by calcination at different temperatures, on microwave absorption was investigated. Remarkably, at 800 °C, Fe3C@NCNTs/CMTs achieved a minimum reflection loss of –35.8 dB and an effective absorption bandwidth of 7.02 GHz at a thickness of only 1.7 mm, even at an ultralow filler loading of 10%, effectively covering the entire Ku band and part of the X band. The excellent microwave absorption performance is attributed to the combined contribution of increased magnetic loss and multiple dielectric polarization mechanisms. This study shows a promising strategy for designing biomass-derived carbon-based broadband microwave absorbing materials.
Journal of Semiconductors (半导体学报 - 中国科学院半导体研究所)•2025•DOI: 10.1088/1674-4926/25030003
Traditional p-type colloidal quantum dot (CQD) hole transport layers (HTLs) used in CQD solar cells (CQDSCs) are commonly based on organic ligands exchange and the layer-by-layer (LbL) technique. Nonetheless, the ligand detachment and complex fabrication process introduce surface defects, compromising device stability and efficiency. In this work, we propose a solution-phase ligand exchange (SPLE) method utilizing inorganic ligands to develop stable p-type lead sulfide (PbS) CQD inks for the first time. Various amounts of tin (II) iodide (SnI2) were mixed with lead halide (PbX2; X = I, Br) in the ligand solution. By precisely controlling the SnI₂ concentration, we regulate the transition of PbS QDs from n-type to p-type. PbS CQDSCs were fabricated using two different HTL approaches: one with 1,2-ethanedithiol (EDT)-passivated QDs via the LbL method (control) and another with inorganic ligand-passivated QD ink (target). The target devices achieved a higher power conversion efficiency (PCE) of 10.93%, compared to 9.83% for the control devices. This improvement is attributed to reduced interfacial defects and enhanced carrier mobility. The proposed technique offers an efficient pathway for producing stable p-type PbS CQD inks using inorganic ligands, paving the way for high-performance and flexible CQD-based optoelectronic devices.
Journal of Semiconductors (半导体学报 - 中国科学院半导体研究所)•2025•DOI: 10.1088/1674-4926/25030031
Quantum key distribution (QKD) achieves information-theoretic security based on quantum mechanics principles, where single-photon detectors (SPDs) serve as critical components. This study focuses on the sinusoidal gated SPDs widely used in high-speed QKD systems. We investigate the mechanisms underlying the rising-edge jitter in detection signals, identifying contributions from factors such as the temporal width of injected optical pulses, avalanche generation processes, avalanche signal extraction, and pulse discrimination. To address the issue of excessive jitter-induced bit errors, we propose a retiming scheme that utilizes coincidence signals synchronized with the sinusoidal gating signal. This approach effectively suppresses detection signal jitter and reduces the after-pulse probability of the detector. Experimental validation using a high-precision time-to-digital converter (TDC) demonstrates a significant reduction in the rising-edge jitter distribution after applying the suppression scheme. The proposed method features clear principles and straightforward engineering implementation, avoiding direct interference with the detector's operational processes. The designed high-speed sinusoidal gated InGaAs/InP SPD operates at 1.25 GHz, achieving a remarkable reduction in after-pulse probability from 10.7% (without jitter suppression) to 0.72%, thereby enhancing the overall performance of QKD systems.
Int. Journal of Mining Science and Technology (采矿与安全工程)•2025•DOI: 10.1016/j.ijmst.2025.08.016
Chalcopyrite is often intergrown with talc, which, after grinding, forms ultrafine particles (<10 lm) that readily coat chalcopyrite surfaces, hindering flotation and causing significant losses in tailings. This study evaluates polyvinyl acetate (PVAc), a thermoplastic polymer, as a selective flocculant to enhance reverse flotation separation of chalcopyrite from ultrafine talc. Flotation tests showed that at a PVAc dosage of 40 mg/L, talc can be effectively and selectively removed, enabling efficient separation. Laser particle size analysis and scanning electron microscopy-energy dispersive spectrometry (SEM-EDS) confirmed that PVAc promotes selective talc aggregation without affecting chalcopyrite. X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations revealed that hydrogen bonding between PVAc ester groups and surface hydroxyls on talc drives the flocculation, while chalcopyrite lacks suitable binding sites. PVAc adsorption also enhances talc hydrophobicity. Furthermore, particle-bubble coverage angle measurements and extended Derjaguin-Landau-Verwey-Overbeek (DLVO) theory theoretical calculations demonstrated that PVAc-induced flocculation increases attractive interactions between talc and bubbles, shifting the total interaction energy from repulsive to attractive and promoting bubble-particle attachment. This study clarifies the selective adsorption and flocculation mechanisms of PVAc and reveals the coupling of flocculation and flotation of ultrafine talc from a particle-bubble capture perspective, while expanding the potential of ester-based polymers for ultrafine mineral recovery.
China Foundry•2025•DOI: 10.1007/s41230-025-5018-9
Abstract: Although the strengthening and grain refinement effects of TiB2 particles on aluminum alloys have been extensively studied, their influence on casting behavior remains relatively underexplored. In this study, the influence of different addition amounts of submicron TiB2 particles on the microstructure, casting performance, and mechanical properties of an Al-Cu (ZL205A) alloy was systematically investigated. The introduction of TiB2 particles leads to significant grain refinement, transforming the microstructure from coarse grains to fine equiaxed grains by providing additional nucleation sites and inhibiting grain growth. SEM and TEM analyses reveal that the added submicron TiB2 particles exhibit minimal effect on the distribution of intermetallic phases or precipitates. Casting performance, as evaluated by spiral fluidity and hot tearing tests, shows notable improvements with TiB2 additions. At a TiB2 content of 3wt.%, the fluidity length increases by 20%, and the hot tearing susceptibility coefficient decreases by 29%. These enhancements are mainly due to the refined grain structure and the formation of interdendritic bridging in TiB2-reinforced alloys. However, the overall enahncement in casting properties shows little variation across the TiB2 additions from 0.2wt.% to 3wt.%. Mechanical testing shows that the highest hardness and strength are achieved with a 1wt.% addition of TiB2 particles, primarily attributed to refined grain size and reinforcement of the aluminum matrix. Based on these findings, a TiB2 particle content of 1wt.% is recommended for optimizing both the casting performance and mechanical properties of the ZL205A alloy.
China Foundry•2025•DOI: 10.1007/s41230-025-5003-3
The performance of an aero-engine is closely related to the cooling ability of the hollow turbine blades. Ceramic core is an important component in the production of hollow turbine blades with a complex structure. As the pace of updating and iteration in turbine blade design continues to accelerate, the internal cavity structures of turbine blades have become increasingly complex. Traditional hot injection process is difficult to meet the production requirements of ceramic cores with complex structures. 3D printing technology can manufacture ceramic cores without the need for moulds, significantly shortening the production cycle and providing a new technology for the production of ceramic cores with complex structures. To meet the technical requirements of the investment casting process, ceramic cores must possess adequate mechanical strength and appropriate porosity. In this work, the ceramic slurry with polysilazane (PSZ) precursor was successfully prepared, and the Al2O3-based ceramic cores with high performance were fabricated using 3D printing technology. The regulation mechanism of polysilazane on the performance of ceramic cores was investigated. The results show that with the increase of PSZ content, the flexural strength of ceramic cores firstly increases and then decreases. When the content of PSZ is 5%, the flexural strength at 25 °C and 1,500 °C are 31.5 MPa and 13.1 MPa, respectively, and the porosity is 36.7%. This work is expected to advance the research and practical application of high-performance ceramic cores fabricated via 3D printing.
Chinese Journal of Mechanical Engineering•2025•DOI: 10.1186/s10033-025-01232-8
Four-Wheel Independent Steering (4WIS) Vehicles can independently control the angle of each wheel, demonstrating superior trajectory tracking performance under normal conditions. However, on intermittent icy and snowy roads, the presence of time-varying adhesion coefficients, time-varying cornering stiffness, and the irregularities due to ice and snow accumulation introduce multiple uncertainties into the steering system, significantly degrading the trajectory tracking performance of 4WIS vehicles. In response, this paper proposes a robust Tube Model Predictive Control (Tube-MPC) trajectory tracking control method for 4WIS. In this method, a Bi-directional Long Short-Term Memory neural network is established for online estimation of tire cornering stiffness under different road adhesion coefficients, providing accurate estimation of time-varying cornering stiffness for each wheel to mitigate the uncertainties of time-varying adhesion coefficients and cornering stiffness. Additionally, considering the road irregularities caused by snow accumulation on intermittent icy and snowy roads, a trajectory tracking controller that integrates Tube-MPC and robust Sliding Mode Control is proposed. The nominal MPC model, developed from the estimated tire cornering stiffness, utilizes the sliding surface and the optimal auxiliary control unit law for the tube is derived from the reaching law in Tube-MPC, aiming to minimize the trajectory tracking error while enhancing the controller’s robustness against road uncertainties. The experiments show that the proposed method outperforms the Tube-MPC algorithm in terms of trajectory accuracy and robustness. This method demonstrates excellent trajectory tracking accuracy under intermittent icy and snowy road conditions, and it lays a theoretical foundation for future studies on vehicle stability and trajectory tracking under such road conditions.
Chinese Journal of Mechanical Engineering•2025•DOI: 10.1186/s10033-025-01336-1
Autonomous driving technology is constantly developing to a higher level of complex scenes, and there is a growing demand for the utilization of end-to-end data-driven control. However, the end-to-end path tracking process often encounters challenges in learning efficiency and generalization. To address this issue, this paper designs a deep deterministic policy gradient (DDPG)-based reinforcement learning strategy that integrates imitation learning and feedforward exploration in the path following process. In imitation learning, the path tracking control data generated by the model predictive control (MPC) method is used to train an end-to-end steering control model of a deep neural network. Another feedforward exploration behavior is predicted by road curvature and vehicle speed, and adds it and imitation learning to the DDPG reinforcement learning to obtain decision-making experience and action prediction behavior of the path tracking process. In the reinforcement learning process, imitation learning is used to update the pre-training parameters of the actor network, and a feedforward steering technique with random noise is adopted for strategy exploration. In the reward function, a hierarchical progressive reward form and a constrained objective reward function referring to MPC are designed, and the actor-critic network architecture is determined. Finally, the path tracking performance of the designed method is verified by comparing various training results, simulations, and HIL tests. The results show that the designed method can effectively utilize pre-training and feedforward prior experience to obtain optimal path tracking performance of an autonomous vehicle, and has better generalization ability than other methods. This study provides an efficient control scheme for improving the end-to-end control performance of autonomous vehicles.
Chinese Journal of Mechanical Engineering•2025•DOI: 10.1186/s10033-025-01292-w
Distributed drive electric vehicles (DDEVs) endow the ability to improve vehicle stability performance through direct yaw-moment control (DYC). However, the nonlinear characteristics pose a great challenge to vehicle dynamics control. For this purpose, this paper studies the DYC through the Takagi-Sugeno (T-S) fuzzy-based model predictive control to deal with the nonlinear challenge. First, a T-S fuzzy-based vehicle dynamics model is established to describe the time-varying tire cornering stiffness and vehicle speeds, and thus the uncertain parameters can be represented by the norm-bounded uncertainties. Then, a robust model predictive control (MPC) is developed to guarantee vehicle handling stability. A feasible solution can be obtained through a set of linear matrix inequalities (LMIs). Finally, the tests are conducted by the Carsim/Simulink joint platform to verify the proposed method. The comparative results show that the proposed strategy can effectively guarantee the vehicle’s lateral stability while handling the nonlinear challenge.
Journal of Central South University•2025•DOI: 10.1007/s11771-025-6114-0
The AlMgScZr high-strength aluminum alloy fabricated by selective laser melting (SLM) technology exhibits a “bimodal microstructure”, resulting in significant non-uniform deformation during thermal deformation. This study investigates the flow behavior of SLM-processed AlMgScZr aluminum alloy utilizing the Gleeble-1500D thermal simulation machine. The true stress−strain curves were amended based on the friction theory. Through determining the Zener-Hollomon parameters, the correlation between flow stress, deformation temperature, and strain rate during the high-temperature thermoplastic deformation of SLM-processed AlMgScZr aluminum alloy with a “bimodal microstructure” was established. In addition, the microstructural evolution during thermal deformation was analyzed. The results indicated that the predicted flow stress values obtained from the Arrhenius constitutive equation with coupled correction of thermal deformation parameters closely matched the experimental values. The correlation coefficient and the average absolute relative error of the corrected model were 0.999 and 2.766%, respectively, accurately predicting the thermoplastic deformation behavior of SLM-processed high-strength aluminum alloy with a “bimodal microstructure”. Furthermore, hot processing maps at different strains were established, identifying stable and unstable regions under different deformation conditions. Microstructural observations revealed different thermal deformation mechanisms under various deformation temperatures. Specifically, dynamic recrystallization characteristics dominated the microstructure at lower temperatures (300−360 ℃), while dynamic recovery was dominant at higher temperatures (390−500 ℃).
Journal of Central South University•2025•DOI: 10.1007/s11771-025-6047-7
The present investigation introduces a composite frequency selective Rasorber (CFSR) that demonstrates a wide −1 dB transmission band, two high absorption bands with absorptivity higher than 90%, and large oblique incidence angles up to 60°. The CFSR consists of four functional layers separated by three dielectric slabs, which includes lossless metasurface-Ⅰ (MS-Ⅰ), loss metasurface-Ⅱ (MS-Ⅱ), loss metasurface-Ⅲ (MS-Ⅲ), and a three-dimensional metastructure (3D-MS). MS-Ⅰ functions as a reflector for two absorption bands with a minimal insertion loss transmission window. MS-Ⅱ is designed for high-frequency absorption. MS-Ⅲ serves as a low-frequency absorption layer for CFSR and an impedance matching layer for MS-Ⅱ. The design methodologies for the transmission window in MS-III and the introduction of 3D-MS are key to achieving high-performance CFSR. The physical mechanisms of CFSR are explained through equivalent circuit model (ECM) analysis and impedance characterization. Finally, measurement results confirm that the proposed CFSR exhibits a −1 dB transmission band ranging from 8.79 to 10.41 GHz with a minimum insertion loss of 0.44 dB at 9.59 GHz; furthermore, the frequency range where reflection coefficient remains below −10 dB is measured to be between 3.33 and 18.00 GHz, aligning well with simulation outcomes.
Journal of Central South University•2025•DOI: 10.1007/s11771-025-6041-0
The effects of pre-compression and pre-aging on the age-hardening response and microstructure of Mg-9.8Sn-3.0Zn (wt.%) alloy have been investigated via hardness test and advanced electron microscopy. The alloy subjected to both pre-compression and pre-aging exhibits the most refined and densest distribution of precipitates upon aging at 200 ℃, leading to the superior age-hardening performance observed in the alloy. Comparatively, the alloy that underwent only pre-aging displayed a greater number density of precipitates than its counterpart that was neither pre-compressed nor pre-aged when both were aged to their peak conditions at 200 ℃, indicating an enhanced age-hardening response in the pre-aged alloy. The precipitates in these three peak-aged alloys consist of Mg2Sn and MgZn2 phases. The reason why the pre-aged alloy has a higher number density of precipitates than the directly aged alloy is that MgZn2 phase formed during pre-aging can serve as heterogeneous nucleation site for the formation of Mg2Sn. The reason why the pre-compression and pre-aged alloy has the highest number density of precipitates is that Mg3Sn and MgZn2 phases formed during pre-aging, alongside lattice defects introduced during pre-compression, collectively act as effective heterogeneous nucleation sites for the formation of Mg2Sn during the subsequent aging at 200 ℃.
Int. Journal of Minerals, Metallurgy and Materials (矿物冶金与材料学报)•2025•DOI: 10.1007/s12613-024-3021-6
A series of high-entropy ceramics with the nominal composition (Mg0.5Zn0.5)0.4+xLi0.4(Ca0.5Sr0.5)0.4−xTiO3 (0 ≤ x ≤ 0.4) has been successfully synthesized using the conventional solid-phase method. The (Mg0.5Zn0.5)0.4+xLi0.4(Ca0.5Sr0.5)0.4−xTiO3 ceramics are confirmed to be composed of the main phase (Zn,Mg,Li)TiO3 and the secondary phase Ca0.5Sr0.5TiO3 by X-ray diffractometer, Rietveld refinement, and X-ray spectroscopy analysis. The quality factor (Q×f) of the samples is inversely proportional to the content of the Ca0.5Sr0.5TiO3 phase, and it is influenced by the density. The secondary phase and molecular polarizability (αT) have a significant impact on the dielectric constant (εr) of the samples. Moreover, the temperature coefficient of resonant frequency (τf) of the samples is determined by the distortion of [TiO6] octahedra and the secondary phase. The results indicate that (Mg0.5Zn0.5)0.4+xLi0.4(Ca0.5Sr0.5)0.4−xTiO3 ceramics achieve ideal microwave dielectric properties (εr = 17.6, Q×f = 40900 GHz, τf = −8.6 ppm/°C) when x = 0.35. (Mg0.5Zn0.5)0.4+xLi0.4(Ca0.5Sr0.5)0.4−xTiO3 ceramics possess the potential for application in wireless communication, and a new approach has been provided to enhance the performance of microwave dielectric ceramics.
Int. Journal of Minerals, Metallurgy and Materials (矿物冶金与材料学报)•2025•DOI: 10.1007/s12613-024-2979-4
The environment-friendly and efficient selective separation of chalcopyrite and molybdenite poses a challenge in mineral processing. In this study, gum Arabic (GA) was initially proposed as a novel depressant for the selective separation of molybdenite from chalcopyrite during flotation. Microflotation results indicated that the inhibitory capacity of GA was stronger toward molybdenite than chalcopyrite. At pH 8.0 with 20 mg/L GA addition, the recovery rate of chalcopyrite in the concentrate obtained from mixed mineral flotation was 67.49% higher than that of molybdenite. Furthermore, the mechanism of GA was systematically investigated by various surface characterization techniques. Contact angle tests indicated that after GA treatment, the hydrophobicity of the molybdenite surface significantly decreased, but that of the chalcopyrite surface showed no apparent change. Fourier transform-infrared spectroscopy and X-ray photoelectron spectroscopy revealed a weak interaction force between GA and chalcopyrite. By contrast, GA was primarily adsorbed onto the molybdenite surface through chemical chelation, with possible contributions from hydrogen bonding and hydrophobic interactions. Pre-adsorbed GA could prevent butyl xanthate from being adsorbed onto molybdenite. Scanning electron microscopy–energy-dispersive spectrometry further indicated that GA was primarily adsorbed onto the “face” of molybdenite rather than the “edge.” Therefore, GA could be a promising molybdenite depressant for the flotation separation of Cu–Mo.
Int. Journal of Minerals, Metallurgy and Materials (矿物冶金与材料学报)•2025•DOI: 10.1007/s12613-024-2896-6
During the continuous casting process of high-Mn high-Al steels, various types of gases such as Ar need to escape through the top of the mold. In which, the behavior of bubbles traversing the liquid slag serves as a restrictive link, closely associated with viscosity and the thickness of liquid slag. In contrast to two-dimensional surface observation, three-dimensional (3D) analysis method can offer a more intuitive, accurate, and comprehensive information. Therefore, this study employs a 3D X-ray microscope (3D-XRM) to obtained spatial distribution and 3D morphological characteristics of residual bubbles in mold flux under different basicity of liquid slag, different temperatures, and different holding times. The results indicate that as basicity of slag increases from 0.52 to 1.03, temperature increases from 1423 to 1573 K, the viscosity of slag decreases, the floating rate of bubbles increases. In addition, when holding time increases from 10 to 30 s, the bubbles floating distance increases, and the volume fraction and average equivalent sphere diameter of the bubbles solidified in the mold flux gradually decreases. In one word, increasing the basicity, temperature, and holding time leading to an increase in the removal rate of bubbles especially for the large. These findings of bubbles escape behavior provide valuable insights into optimizing low basicity mold flux for high-Mn high-Al steels.