Opto-Electronic Advances (光电进展)•2026•DOI: 10.29026/oea.2026.250274
Thin-film lithium niobate (TFLN) has emerged as a promising platform for integrated photonics due to its strong electro-optic and nonlinear properties. However, on-chip tunable lasers essential for optical communications, sensing, metrology, and quantum technology remain constrained by limited tuning range or precision, often requiring complex control strategies. This work demonstrates a hybrid integrated electro-optically tunable narrow-linewidth III-V laser on TFLN, achieving a tuning range of ~51.8 nm, an intrinsic linewidth of ~1.21 MHz, and a tuning precision of ~0.03 nm. The external cavity uniquely combines highly reflective Sagnac mirrors and a series of unbalanced interferometers, providing a spectral response that favors single-longitudinal-mode narrow-linewidth lasing. Experimental results show a maximum on-chip power of 102.7 μW at 1551.69 nm, a side-mode suppression ratio of 39.65 dB, and continuous tuning range of ~3.5 pm. The laser operates mode-hop-free over long periods, with a DC voltage tuning range of −30 V to +30 V. The external cavity, built exclusively on single-mode-waveguide-based photonic structures, ensures fundamental-mode propagation, enhancing stability and relaxing fabrication tolerances. The reformulated theory of semiconductor lasers provides design insights for hybrid integrated lasers and on-chip self-injection locked lasers. This work advances the development of high-precision, wide-range tunable lasers for next-generation photonic systems.
Journal of Advanced Ceramics•2026•DOI: 10.26599/JAC.2026.9221339
Practical deployment of Li4SiO4 as a high-temperature CO2 sorbent requires pelletization, which inevitably densifies the microstructure and imposes severe CO2 diffusion limitations. Conventional sacrificial pore-forming agents address this issue but remain single-purpose, serving solely as structural templates without conferring chemical benefits. Here, we demonstrate that spent coffee grounds (SCGs), an abundant food-industry waste, can serve as a single-source modifier that achieves three colocalized enhancements in Li4SiO4 pellets: hierarchical pore engineering, in situ K-doping, and oxygen vacancy generation. The thermal decomposition of SCG creates an interconnected hierarchical macroporous network that effectively reduces intraparticle CO2 diffusion resistance. Meanwhile, the mineral-rich SCG ash provides in situ potassium doping, generating a localized eutectic molten carbonate phase that accelerates liquid-phase ion transport. Crucially, the transient reducing atmosphere during biomass combustion introduces oxygen vacancies into the silicate lattice; density functional theory (DFT) calculations reveal that these vacancies serve as highly active CO2 adsorption sites with a strongly exothermic adsorption energy of −0.914 eV. Benefiting from this triple-synergistic enhancement, the SCG-modified sorbent (LSO-50) achieves a CO2 adsorption capacity of 0.275 g/g at 650 °C under 15 vol% CO2, representing a more than fourfold improvement over unmodified pellets. When further combined with Na2CO3 codoping to promote additional eutectic formation, the optimized sorbent (LSON-50) reaches 0.330 g/g, retains 0.284 g/g after 50 adsorption–desorption cycles, and exhibits robust mechanical stability (< 10% attrition loss). By colocating structural, chemical, and defect features within a single biomass-derived modifier, this work establishes a scalable waste-valorization route for high-performance, eco-friendly CO2 capture.
Int. Journal of Mining Science and Technology (采矿与安全工程)•2026•DOI: 10.1016/j.ijmst.2026.03.004
The energy-driven progressive brittle shear failure of rock joints is a key mechanism behind deep engineering disasters such as joint-induced rockbursts and engineering earthquakes. To investigate the energy evolution mechanisms and disaster proneness, monotonic and stepwise loading-unloading tests were performed on regular dentate joints under constant normal stiffness boundary conditions. Results indicate a transition in damage mechanism from climbing wear of low-inclination asperities to brittle rupture of high-inclination ones, accompanied by a marked decrease in irreversible displacement. Energy analysis reveals a strong linear relationship between pre-peak elastic energy density and both input energy density and shear stress squared. The post-peak elastic energy release rate (g) and the self-sustaining instability coefficient (l) increase with joint undulation. A dimensionless brittleness index (BI) integrating the complete energy conversion and release process was proposed to quantify the energy balanced budget. The highly undulated joint R4 showed the most pronounced brittleness and instability intensity with the highest BI value of 0.697, along with g = 0.774 and l = 0.611. This study provides deeper insight into the understanding of the disaster-inducing proneness and stability assessment in jointed rock mass.
China Foundry•2026•DOI: 10.1007/s41230-026-5150-1
Optimizing the mechanical properties and fluidity of hypoeutectic Al-Si alloys in high-pressure die casting (HPDC) is critical for manufacturing thin-walled components with large sizes. The performance and fluidity of castings over long flow distances depend on the precise control of solidification behavior during the complex HPDC process. In this study, an AlSi10MnMg alloy was fabricated using a fluidity test mold with three channels of different thicknesses to investigate the influence of varying TiB2 content on the microstructure, mechanical properties, and fluidity of the alloy during long-distance filling in HPDC. Results indicate that the addition of 0.018wt.% TiB2 significantly reduces externally solidified crystals (ESCs) and porosity contents, improving the filling distance from 1,700 mm to 1,833 mm. The reduction in ESCs in the castings by TiB2 is attributed to its ability to promote the migration of ESCs from the shot sleeve toward the melt center, where temperature and flow velocity are higher. At a filling distance of 1,300 mm, the ultimate tensile strength (UTS), yield strength (YS), and elongation increase notably with addition of 0.018wt.% TiB2. When the addition of TiB2 increases to 0.036wt.%, the area fraction of ESCs in the channel increases compared to that with 0.018wt.%, and the filling distance slightly decreases to 1,796.9 mm. The mechanical properties of the alloy with 0.036wt.% TiB2 are better than those of the alloy with 0.018wt.% TiB2 over short distances, but become inferior beyond 1,000 mm. This work reveals the role of TiB2 in regulating solidification and flow during long-range filling, offering new insights into the processability of HPDC Al-Si alloys.
Nano-Micro Letters•2026•DOI: 10.1007/s40820-025-01989-6
Two-dimensional materials for flexible energy storage commonly face huge challenges in limited active surface and hindered charge transport. Herein, we report an innovative asymmetric pseudocapacitor based on synergistic design of modified MXene and graphene, integrating gas-induced rapid expansion technology and precise surface chemical regulation methods. For graphene modification, rapid vaporization induces exfoliation and expansion of graphene oxide layers. Subsequently, pseudocapacitive oxygen-containing groups were selectively introduced through acid oxidation, yielding expanded-and-oxidized graphene (OEG) for positive porous-nanopaper electrode. For MXene modification, alkali-treated MXene underwent hydrazine assistance to facilitate gas expansion and –NH2 grafting, producing MXene-NH2 (NOM) for negative porous-nanopaper electrode. Density functional theory calculations show that –COOH more effectively modulate graphene’s electronic structure by inducing charge redistribution and creating active sites, thereby enhancing H+ adsorption and ion interactions compared to –OH. Meanwhile, –NH2 on MXene enable electron delocalization and dynamic Ti–N–H+ interactions, speeding up proton adsorption/desorption and boosting both pseudocapacitance and conductivity. Through collaborative optimized spatial architecture and surface properties, flexible OEGB and NOMB exhibited of 333.6 and 500.5 F g−1 at high mass loading, respectively. The assembled proton pseudocapacitor readily achieved energy and power densities of 58.9 Wh kg−1 and 3802 W kg−1, respectively, with excellent stability for potential applications.
Nano-Micro Letters•2026•DOI: 10.1007/s40820-025-01979-8
Space exploration and manufacturing are of critical importance for scientific advancement, technological innovation, national security, and the acquisition of extraterrestrial resources. In view of this, chemical and biological nano-/micro-/meso-scale manufacturing provide complementary approaches to overcome key space exploration challenges by enabling the in-situ production of essential life-support materials, propellants, and other resources. This review examines the origin and historical evolution of space manufacturing and the latest advances across different environments—from orbital space stations and the lunar surface to Mars and asteroids. It is structured to present the current state of research, outline key manufacturing strategies and technologies, assess the technical and environmental challenges, and discuss emerging trends and future directions. Besides, the potential applications of emerging technologies such as synthetic biology and artificial intelligence in overcoming the limitations of microgravity, limited resources, and extreme conditions are discussed. Ultimately, this integrative review could serve to guide future development, from advancing space science and disruptive manufacturing to enabling interdisciplinary and application-level innovations.
Journal of Central South University•2026•DOI: 10.1007/s11771-026-6267-5
Previous earthquakes indicate that near-source canyon topographic effect (NCTE) can substantially amplify the seismic responses of canyon-crossing bridges (CCBs). While the conventional practices are to make disaster response decisions based on the deterministic approaches, they cannot provide a holistic view regarding the impacts of uncertainties of ground motions on CCBs. Thus, this study adopts the performance-based seismic assessment in a probabilistic framework to evaluate the seismic fragility of CCBs considering NCTE. For this purpose, a numerical model of a typical tall-pier CCB across a V-shaped canyon is constructed using OpenSees. Eighteen ground motions combined with NCTE are simulated using the region-matching method. Peak ground acceleration (PGA), spectral acceleration at the fundamental period T1 (Sa(T1)), and peak ground velocity (PGV) are compared to determine the optimal intensity measure (IM). The probabilistic seismic demand models and fragility curves are constructed. The results show that PGV is the optimal IM for ground motions considering NCTE. The NCTE can significantly increase the damage probability of CCBs. The damage probability of the side bearing is the most sensitive to NCTE among the vulnerable components. The side pier bearings and the side piers on the illuminated canyon side may be the most vulnerable components considering the NCTE effect.
Nano-Micro Letters•2025•DOI: 10.1007/s40820-025-01795-0
Historically seen as a limitation, grain boundaries (GBs) within polycrystalline metal halide perovskite (MHP) films are thought to impede charge transport, adversely impacting the efficiency of perovskite solar cells (PSCs). In this study, we employ home-built confocal photoluminescence microscopy, combined with photocurrent detection modules, to directly visualize the carrier dynamics in the MHP film of PSCs under real operating conditions. Our findings suggest that GBs in high-efficiency PSCs function as carrier transport channels, where a notable enhancement in photocurrent is observed. Femtosecond transient absorption and Kelvin probe force microscopy measurements further validate the existence of a built-in electric field in the vicinity of GBs, offering additional driving force for charge separation and establishing channels for swift carrier transport along the GBs, thereby expediting subsequent charge collection processes. This study elucidates the pivotal role of GBs in operational PSCs and provides valuable insights for the fabrication of high-efficiency PSCs.
Nano-Micro Letters•2025•DOI: 10.1007/s40820-025-01793-2
With high surface-to-volume ratio, the abundant surface states and high carrier concentration are challenging the near-infrared photodetection behaviors of narrow band gap semiconductors nanowires. In this study, the narrow band gap semiconductor of Bi2O2Se nanosheets (NSs) is adopted to construct mixed-dimensional heterojunctions with GaSb nanowires (NWs) for demonstrating the impressive self-powered NIR photodetection. Benefiting from the built-in electric field of ~140 meV, the as-constructed NW/NS mixed-dimensional heterojunction self-powered photodetector shows the low dark current of 0.07 pA, high Ilight/Idark ratio of 82 and fast response times of <2/2 ms at room temperature. The self-powered photodetector performance can be further enhanced by fabricating the NW array/NS mixed-dimensional heterojunction by using a contact printing technique. The excellent photodetection performance promises the as-constructed NW/NS mixed-dimensional heterojunction self-powered photodetector in imaging and photocommunication.
Nano-Micro Letters•2025•DOI: 10.1007/s40820-024-01638-4
Magnetic absorbers with high permeability have significant advantages in low-frequency and broadband electromagnetic wave (EMW) absorption. However, the insufficient magnetic loss and inherent high conductivity of existing magnetic absorbers limit the further expansion of EMW absorption bandwidth. Herein, the spinel (FeCoNiCrCu)3O4 high-entropy oxides (HEO) are successfully constructed on the surface of FeCoNiCr0.4Cu0.2 high-entropy alloys (HEA) through low-temperature oxygen bath treatment. On the one hand, HEO and HEA have different magnetocrystalline anisotropies, which is conducive to achieving continuous natural resonance to improve magnetic loss. On the other hand, HEO with low conductivity can serve as an impedance matching layer, achieving magneto-electric co-modulation. When the thickness is 5 mm, the minimum reflection loss (RL) value and absorption bandwidth (RL < −5 dB) of bi-phase high-entropy composites (BPHEC) can reach −12.8 dB and 633 MHz, respectively. The RCS reduction value of multilayer sample with impedance gradient characteristic can reach 18.34 dB m2. In addition, the BPHEC also exhibits temperature-stable EMW absorption performance, high Curie temperature, and oxidation resistance. The absorption bandwidth maintains between 593 and 691 MHz from −50 to 150 °C. This work offers a new and tunable strategy toward modulating the electromagnetic genes for temperature-stable ultra-broadband megahertz EMW absorption.
Nano-Micro Letters•2025•DOI: 10.1007/s40820-025-01653-z
Seawater electrolysis offers a promising pathway to generate green hydrogen, which is crucial for the net-zero emission targets. Indirect seawater electrolysis is severely limited by high energy demands and system complexity, while the direct seawater electrolysis bypasses pre-treatment, offering a simpler and more cost-effective solution. However, the chlorine evolution reaction and impurities in the seawater lead to severe corrosion and hinder electrolysis’s efficiency. Herein, we review recent advances in the rational design of chlorine-suppressive catalysts and integrated electrolysis systems architectures for chloride-induced corrosion, with simultaneous enhancement of Faradaic efficiency and reduction of electrolysis’s cost. Furthermore, promising directions are proposed for durable and efficient seawater electrolysis systems. This review provides perspectives for seawater electrolysis toward sustainable energy conversion and environmental protection.
New Carbon Materials (新型炭材料)•2025•DOI: 10.1016/S1872-5805(NCM2024-39-05-08)
In the development of rechargeable lithium ion batteries (LIBs), silicon anodes have attracted much attention because of their extremely high theoretical capacity, relatively low Li-insertion voltage and the availability of silicon resources. However, their large volume expansion and fragile solid electrolyte interface (SEI) film hinder their commercial application. To solve these problems, Si has been combined with various carbon materials to increase their structural stability and improve their interface properties. The use of different carbon materials, such as amorphous carbon and graphite, as three-dimensional (3D) protective anode coatings that help buffer mechanical strain and isolate the electrolyte is detailed, and novel methods for applying the coatings are outlined. However, carbon materials used as a protective layer still have some disadvantages, necessitating their modification. Recent developments have focused on modifying the protective carbon shells, and substitutes for the carbon have been suggested.
New Carbon Materials (新型炭材料)•2025•DOI: 10.1016/S1872-5805(NCM2024-39-02-02)
Lithium-sulfur (Li-S) batteries are among the most promising next-generation electrochemical energy-storage systems due to their exceptional theoretical specific capacity, inexpensive production cost and environmental friendliness. However, the poor conductivity of S and Li2S, severe lithium polysulfide (LiPS) shuttling and the sluggish redox kinetics of the phase transformation greatly hinder their commercialization. Carbonaceous materials could be potentially useful in Li-S batteries to tackle these problems with their high specific surface area to host LiPSs and sulfur and excellent electrical conductivity to increase electron transfer rate. However, non-polar carbon materials are unable to interact closely with the highly polar polysulfides, resulting in a low sulfur utilization and a serious shuttle effect. Because of their advantages of strong polarity and a large number of adsorption sites, integrating transition metal oxides (TMOs) with carbon-based materials (CMs) increases the chemical adsorption of LiPSs and electrochemical reaction activity for LiPSs. The working principles and main challenges of Li-S batteries are discussed followed by a review of recent research on the ex-situ and in-situ synthesis of TMO/CM composites. The formation of TMO/CMs with the dimensionalities of CMs from 1D to 3D are then reviewed together with ways of changing their structure, including heterostructure design, vacancy engineering and facet manipulation. Finally, the outlook for using TMO/CMs in Li-S batteries is considered.
New Carbon Materials (新型炭材料)•2025•DOI: 10.1016/S1872-5805(NCM2024-39-01-09)
Designing efficient and robust catalysts for hydrogen evolution reaction (HER) is imperative for saline water electrolysis technology. A catalyst composed of CoxP nanowires array with N-doped carbon nanosheets (NC) was fabricated on Ni foam (NF) by an in-situ growth strategy. The material is designated as NC/CoxP@NF. In the preparation process, Co(OH)2 nanowires were transformed into a metal organic framework of cobalt (ZIF-67) on NF by the dissolution-coordination of endogenous Co2+ and 2-methylimidazole. The resulting cactus-like microstructure gives NC/CoxP@NF abundant exposed active sites and ion transport channels, which improve the HER catalytic reaction kinetics. Furthermore, the interconnected alternating nanowires and free-standing nanosheets in NC/CoxP@NF improve its structural stability, and the formation of surface polyanions (phosphate) and a NC nanosheet protective layer improve the anti-corrosive properties of catalysts. Thus, the NC/CoxP@NF has an excellent performance, requiring overpotentials of 107 and 133 mV for HER to achieve 10 mA cm−2 in 1.0 mol L−1 KOH and 1.0 mol L−1 KOH + 0.5 mol L−1 NaCl, respectively. This in-situ transformation strategy is a new way of constructing highly-efficient HER catalysts for saline water electrolysis.
Journal of Semiconductors (半导体学报 - 中国科学院半导体研究所)•2025•DOI: 10.1088/1674-4926/25010010
Infrared and terahertz waves constitute pivotal bands within the electromagnetic spectrum, distinguished by their robust penetration capabilities and non-ionizing nature. These wavebands offer the potential for achieving high-resolution and non-destructive detection methodologies, thereby possessing considerable research significance across diverse domains including communication technologies, biomedical applications, and security screening systems. Two-dimensional materials, owing to their distinctive optoelectronic attributes, have found widespread application in photodetection endeavors. Nonetheless, their efficacy diminishes when tasked with detecting lower photon energies. Furthermore, as the landscape of device integration evolves, two-dimensional materials struggle to align with the stringent demands for device superior performance. Topological materials, with their topologically protected electronic states and non-trivial topological invariants, exhibit quantum anomalous Hall effects and ultra-high carrier mobility, providing a new approach for seeking photosensitive materials for infrared and terahertz photodetectors. This article introduces various types of topological materials and their properties, followed by an explanation of the detection mechanism and performance parameters of photodetectors. Finally, it summarizes the current research status of near-infrared to far-infrared photodetectors and terahertz photodetectors based on topological materials, discussing the challenges faced and future prospects in their development.
Transactions of Nonferrous Metals Society of China (中国有色金属学报)•2025•DOI: 10.1016/S1003-6326(25)66952-4
The effects of artificial aging (T6) on the creep resistance with tensile stresses in the range of 50−80 MPa at 175 °C were investigated for an extruded Mg−1.22Al−0.31Ca−0.44Mn (wt.%) alloy. The Guinier-Preston (G.P.) zones primarily precipitate in the sample aged at 200 °C for 1 h (T6-200°C/1h), while the Al2Ca phases mainly precipitate in the sample aged at 275 °C for 8 h (T6-275°C/8h). The T6-200°C/1h sample exhibits excellent creep resistance, with a steady-state creep rate one order of magnitude lower than that of the T6-275°C/8h sample. The abnormally high stress exponent (~8.2) observed in the T6-200°C/1h sample is associated with the power-law breakdown mechanism. TEM analysis illuminates that the creep mechanism for the T6-200°C/1h sample is cross-slip between basal and prismatic dislocations, while the T6-275°C/8h sample exhibits a mixed mechanism of dislocation cross-slip and climb. Compared with the Al2Ca phase, the dense G.P. zones effectively impede dislocation climb and glide during the creep process, demonstrating superior creep resistance of the T6-200°C/1h sample.
Int. Journal of Mining Science and Technology (采矿与安全工程)•2025•DOI: 10.1016/j.ijmst.2025.07.009
As the main geomaterials for coral reefs oil or gas extraction and underground infrastructure construction, coral reef limestone demonstrates significantly distinct mechanical responses compared to terrigenous rocks. To investigate the mechanical behaviour of coral reef limestone under the coupling impact of size and strain rate, the uniaxial compression tests were conducted on reef limestone samples with length-to-diameter (L/D) ratio ranging from 0.5 to 2.0 at strain rate ranging from 10−5 s−1 to 10−2 s−1. It is revealed that the uniaxial compressive strength (UCS) and residual compressive strength (RCS) of coral reef limestone exhibits a decreasing trend with L/D ratio increasing. The dynamic increase factor (DIF) of UCS is linearly correlated with the logarithm of strain rate, while increasing the L/D ratio further enhances the DIF. The elastic modulus increases with strain rate or L/D ratio increasing, whereas the Poisson’s ratio approximates to a constant value of 0.24. The failure strain increases with strain rate increasing or L/D ratio decreasing, while the increase in L/D ratio will inhibit the enhancing effect of the strain rate. The high porosity and low mineral strength are the primary factors contributing to a high RCS of 16.7%–64.9% of UCS, a lower brittleness index and multiple irregular fracture planes. The failure pattern of coral reef limestone transits from the shear-dominated to the splitting-dominated failure with strain rate increasing or L/D ratio decreasing, which is mainly governed by the constrained zones induced by end friction and the strain rate-dependent crack propagation. Moreover, a predictive formula incorporating coupling effect of size and strain rate for the UCS of reef limestone was established and verified to effectively capture the trend of UCS.
Int. Journal of Mining Science and Technology (采矿与安全工程)•2025•DOI: 10.1016/j.ijmst.2025.12.017
Given the high porosity, strong connectivity, and low strength of reef limestone, microbial-induced carbonate precipitation (MICP) reinforcement tests were performed under different grouting cycles. CT-based three-dimensional reconstruction, uniaxial compression, and acoustic emission analyses were employed to elucidate the coupling mechanism between microstructural evolution and macroscopic mechanical behavior. MICP-induced calcium carbonate deposition exhibited distinct scale selectivity, initially occurring in large pores and highly coordinated nodes, which reduced the average pore diameter from 221.26 μm to 75.36 μm and transformed the pore network from a highly connected loose type to a dense isolated one. The elastic modulus increased from 3.27 GPa to 6.21 GPa, and the peak strength approximately doubled, while the failure mode evolved from brittle to brittle–ductile. Acoustic emission analysis revealed a greater proportion of post-peak high-energy events and a frequency shift from high to mid–low ranges, indicating a multi-stage energy dissipation process. A reinforcement variable was introduced to quantify the MICP-induced strengthening, and a structural densification factor was incorporated to establish a constitutive model governed by densification. The study clarifies the coupling mechanism from microscopic densification to macroscopic enhancement, providing theoretical support for the green reinforcement of highly porous rock masses.
Int. Journal of Minerals, Metallurgy and Materials (矿物冶金与材料学报)•2025•DOI: 10.1007/s12613-025-3099-5
Doping small amounts at the A-site or B-site of SmCrO3 ceramics is a promising approach for modifying their microstructure, as well as their magnetic and dielectric properties. In this study, polycrystalline ceramics of Sm1−xNixCrO3 (x = 0, 0.05, and 0.20) and SmCr1−yNiyO3 (y = 0.05 and 0.20) were synthesized via a conventional solid-state reaction. X-ray diffraction validated that all the doped ceramics maintained an orthorhombic crystalline structure consistent with the Pbnm space group. Furthermore, X-ray photoelectron spectroscopy demonstrated the presence of Ni2+ ions in the doped specimens. Notably, doping resulted in significant enhancement of low-temperature magnetic properties, particularly in samples doped at the A-site, such as Sm0.80Ni0.20CrO3. Compared with the pristine sample, the maximum magnetization of Sm0.80Ni0.20CrO3 increased by approximately 60.9% and 93.5% in the zero-field cooling and field-cooling modes, respectively, in an external magnetic field of 100 Oe. Furthermore, the dielectric constants of the Ni-doped ceramics initially exceeded that of the pristine sample as the temperature increased. At equivalent doping ratios, A-site doping demonstrated superior performance over B-site doping, including higher magnetization, lower dielectric loss, and enhanced electrical quality factors.
Chinese Journal of Mechanical Engineering•2025•DOI: 10.1186/s10033-025-01197-8
During the metal cutting process, especially in continuous contact conditions like turning, the challenge of lubricants failing to effectively reach the cutting point remains unresolved. Micro-textured cutting tools offer a potential solution for tool-chip contact challenges. Inspired by the evolutionary achievements of the biosphere, micro-textures are expected to overcome lubrication limitations in cutting zones. Drawing on the anti-gravity water transport seen at the mouth edge of the Nepenthes plant, an innovative microchannel with Nepenthes-shaped contours was designed on the rake face to enable controlled lubricant transport. However, the dynamics of lubricant delivery on textured surfaces are not fully understood. This study first analyzed the microstructure and water transport mechanism of Nepenthes to reconstruct a micro-textured surface for controlled lubricant transport. A dynamic model was then developed to describe lubricant transport within open microchannels, with mathematical simulations predicting transport speed and flow distance. To validate this model, diffusion experiments of alumina soybean oil nanolubricant on polycrystalline diamond (PCD) cutting tool surfaces were conducted, showing an average prediction deviation of 5.01%. Compared with the classical Lucas-Washburn model, the new model improved prediction accuracy by 4.72%. Additionally, comparisons were made to examine droplet spreading and non-uniform diffusion on textured surfaces, revealing that the T2 surface exhibited the strongest unidirectional diffusion characteristics. The contact angle ratio, droplet unidirectional spreading ratio, and droplet spreading aspect ratio were 0.48, 1.75, and 3.99, respectively. Finally, the anti-wear, friction-reducing, and efficiency-enhancing mechanisms of micro-textured surfaces in minimum quantity lubrication turning were analyzed. This approach may support continuous cutting of difficult-to-machine materials.
Chinese Journal of Mechanical Engineering•2025•DOI: 10.1186/s10033-025-01280-0
Microgrinding is widely used in clinical bone surgery, but saline spray cooling faces technical challenges such as low wettability at the microgrinding tool–bone interface, easy clogging of the microgrinding tools, and high grinding temperatures. These issues can lead to bone necrosis, irreversible thermal damage to nerves, or even surgical failure. Inspired by the water-trapping and directional transportation abilities of desert beetles, this study proposes a biomimetic desert beetle microgrinding tool. The flow-field distribution directly influences the convective heat transfer of the cooling medium in the grinding zone, which in turn affects the grinding temperature. To address this, a mathematical model of the two-phase flow field at the biomimetic microgrinding tool–bone interface is developed. The results indicate an average error of 14.74% between the calculated and experimentally obtained airflow field velocities. Next, a biomimetic desert beetle microgrinding tool is prepared. Experiments with physiological saline spray cooling were conducted on fresh bovine femur bone, which has mechanical properties similar to human bone. Results show that, compared with conventional microgrinding tools, the biomimetic tools reduced bone surface temperature by 21.7%, 13.2%, 5.8%, 20.3%, and 25.8% at particle sizes of 150#, 200#, 240#, 270#, and 300#, respectively. The surface morphology of the biomimetic microgrinding tools after grinding is observed and analyzed, revealing a maximum clogging area reduction of 23.0%, which is 6.1%, 6.0%, 10.0%, 15.6%, and 9.5% less than that observed with conventional tools. Finally, this study unveils the dynamic mechanism of cooling medium transfer in the flow field at the biomimetic microgrinding tool–bone interface. This research provides theoretical guidance and technical support for clinical bone resection surgery.
Chinese Journal of Mechanical Engineering•2025•DOI: 10.1186/s10033-025-01241-7
A sudden increase in the radial depth (SIRD) is a distinctive phenomenon in plunge milling. It is typically characterized by a sharp increase in cutting force at the end of the axial feed of the tool, accompanied by harsh machine vibration sounds, which can negatively impact the reliability of plunge milling. This paper proposes an optimization method to eliminate SIRD in five-axis plunge milling. Initially, a five-axis plunge milling experiment and an analysis of the spatial position relationship between the plunge tools and the workpiece revealed that the cause of SIRD is unreasonable tool path planning. Subsequently, using the cutter position and cutter axis vector as variables, an SIRD discrimination model was developed for adjacent cutter positions and extended to multiple cutter positions. Optimizing the plunge milling tool path is considered a multivariate optimization problem that involves determining the cutter point and cutter axis vector. The SIRD discrimination model was used as a constraint function to aid in solving for the variables. The simulation and experimental results indicate that with the remaining volume of material as the optimization target, the optimized plunge milling tool path results in a residual material volume that is less than 60% of the gradually decreasing plunge depth. This optimization decreases the subsequent semi-finishing time of the workpiece and enhances machining efficiency. Additionally, it does not rely on operator experience and facilitates efficient automated optimization of the tool path to exclude SIRD.
Chinese Journal of Mechanical Engineering•2025•DOI: 10.1186/s10033-025-01347-y
The average stiffness performance indices throughout the workspace are commonly used as global stiffness performance indices to evaluate the overall stiffness performance of parallel mechanisms, which involves an analysis of the stiffness performance of numerous discrete points in the workspace. This necessitates time-consuming and inefficient calculation, which is particularly pronounced in the optimization design stage of the mechanism, where the variations in the global stiffness performance indices versus various dimensional and structural parameters need to be analyzed. This paper presents a semi-analytical approach for stiffness modeling of the novel (R(RPS&RP))&2-UPS parallel mechanism (referred to as the Trifree mechanism) and proposes “local” stiffness performance indices as alternatives to global indices. Drawing on the screw theory, the Cartesian stiffness matrix of the Trifree mechanism is formulated explicitly by considering the compliances of all elastic elements and the over-constraint characteristics inherent in the mechanism. Based on the spherical motion pattern of the Trifree mechanism, four special reference configurations are extracted within the workspace. This yields “local” stiffness performance indices capable of accurately evaluating the overall stiffness performance of the mechanism and effectively improving the computational efficiency. The variations in global and “local” stiffness performance indices versus key design parameters are investigated. Furthermore, the proposed indices are applied to the Tricept and Trimule mechanisms. The results demonstrate that the proposed indices exhibit excellent computational accuracy and efficiency in evaluating the overall stiffness performance of these spherical parallel mechanisms. Moreover, the stiffness performance of the novel parallel mechanism investigated in this study closely resembles that of the well-known Tricept and Trimule mechanisms. This research proposes a semi-analytic stiffness model of the Trifree mechanism and “local” stiffness performance indices to evaluate the overall stiffness performance, thereby substantially improving the computational efficiency without sacrificing accuracy.
Chinese Journal of Mechanical Engineering•2025•DOI: 10.1186/s10033-025-01341-4
The electromagnetic pulse valve, as a key component in baghouse dust removal systems, plays a crucial role in the performance of the system. However, despite the promising results of intelligent fault diagnosis methods based on extensive data in diagnosing electromagnetic valves, real-world diagnostic scenarios still face numerous challenges. Collecting fault data for electromagnetic pulse valves is not only time-consuming but also costly, making it difficult to obtain sufficient fault data in advance, which poses challenges for small sample fault diagnosis. To address this issue, this paper proposes a fault diagnosis method for electromagnetic pulse valves based on deep transfer learning and simulated data. This method achieves effective transfer from simulated data to real data through four parameter transfer strategies, which combine parameter freezing and fine-tuning operations. Furthermore, this paper identifies a parameter transfer strategy that simultaneously fine-tunes the feature extractor and classifier, and introduces an attention mechanism to integrate fault features, thereby enhancing the correlation and information complementarity among multi-sensor data. The effectiveness of the proposed method is evaluated through two fault diagnosis cases under different operating conditions. In this study, small sample data accounted for 7.9% and 8.2% of the total dataset, and the experimental results showed transfer accuracies of 93.5% and 94.2%, respectively, validating the reliability and effectiveness of the method under small sample conditions.
Chinese Journal of Mechanical Engineering•2025•DOI: 10.1186/s10033-025-01286-8
This study aims to develop an accurate calculation model of transmission torque and load-bearing capacity for hydro-viscous clutches (HVC) used in high-power vehicles, which is important to investigate the step-less speed regulation characteristics in a fan drive system. However, most of the existing models ignore the distribution differences of groove area along the radial direction, which may lead to significant deviations in calculating the mechanical property of friction pairs related to operating conditions and the engagement process. To fill this gap, a new calculation model for bearing capacity and frictional torque of friction pairs with different oil grooves is proposed, in which the traditional fixed contact area ratio coefficient for oil groove measurement is replaced by a more precise discrete micro-ring area ratio (DMAR) integration method. Then, a 32-degree-of-freedoms dynamic model of HVC at a fan drive system is established for the prediction of dynamic responses during speed regulation. Results show that friction pairs with different oil grooves have a direct influence on frictional torque and bearing capacity through the change of DMAR along the radial direction. The friction pairs with different groove structures have oscillation phenomena at the engagement steady-state boundary. Furthermore, a step-less speed regulation experimental setup is established to verify the correctness of the proposed model. It is demonstrated that the axial engagement force and the speed regulation curve predicted by the proposed method are in good agreement with the experimental data. The results could effectively predict the engagement dynamic characteristics. The numerical relationship among the structure parameters, the mechanical properties of friction pairs, and the speed regulation characteristics of the system are established through the proposed model, which lays a theoretical foundation for the structure design of friction plates and optimization of step-less speed regulation performance.
Int. Journal of Minerals, Metallurgy and Materials (矿物冶金与材料学报)•2025•DOI: 10.1007/s12613-025-3225-4
The effects of direct aging (DA) on the microstructure and mechanical properties of TiB2/AlSi7Mg alloys fabricated via laser powder bed fusion (LPBF) were systematically investigated. DA significantly improves strength while maintaining satisfactory ductility. Optimal performance is obtained through under-aging (UA) at 150°C for 4 h, resulting in a yield strength of 361 MPa, tensile strength of 503 MPa, and elongation of 9.1% in the horizontal direction. DA does not substantially alter the grain size or cellular structure but promotes the formation of nanoprecipitates within the α-Al matrix. Specifically, UA induces dot-like and needle-like Si precipitates, whereas over-aging (OA) additionally generates short rod-like β'-Mg1.8Si phases. The strengthening mechanism is attributed to the Hall–Petch effect associated with grain and cell boundaries, and the Orowan mechanism induced by nanoprecipitates. Work-hardening behavior is governed by interactions between dislocations and nanoprecipitates. The OA sample exhibits rapid saturation of work hardening due to a high initial hardening rate and dynamic recovery of dislocations, resulting in limited uniform elongation. In contrast, the UA sample demonstrates a more balanced work hardening response. These findings provide theoretical and experimental validation of DA as an effective post-processing approach aimed at enhancing the performance of LPBF Al–Si–Mg alloys in engineering applications.
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 Minerals, Metallurgy and Materials (矿物冶金与材料学报)•2025•DOI: 10.1007/s12613-025-3140-8
Using cemented rockfill to replace coal pillars offers an effective solution for reducing solid waste while ensuring the safety of gob-side entries. However, achieving the balance among low cost, high waste recycling rates, and adequate strength remains a significant challenge for cemented rockfill. This study used a composite alkali activator to activate gangue cemented rockfill. The compressive strength, scanning electron microscopy, energy dispersive spectrometer, mercury intrusion porosimetry, X-ray diffraction, and thermogravimetric tests were carried out to investigate the effect of the composite alkali activator proportion on the compressive strength, microstructure, and composition of the cemented rockfill. The calcium silicate hydrate (C–S–H) molecular model of cemented rockfill was constructed to explore the fracture evolution of the nucleated molecular structure under tension. The results show that compressive strength initially increased and then decreased with the activator proportion, the optimal activator proportion of 1:2 resulted in a 31.25% increase in strength at 3 d. This reasonable activator proportion strengthens the pozzolanic effect of gangue, and consumes more calcium hydroxide to inhibit its agglomeration, ultimately achieving the densification of microstructure. The activator proportion inevitably substitutes calcium ions with sodium ions in the C–S–H molecular model. The 12% substitution of calcium ions increases the adhesion between silicon chain layers, which is beneficial to the interlayer stress transfer. This work proposes a method for preparing low-cost cemented rockfill from alkali-activated gangue, which can be used for solid waste recycling and reducing cement consumption to achieve low-carbon goals.