Opto-Electronic Advances (光电进展)•2026•DOI: 10.29026/oea.2026.250197
Artificial compound eyes (CEs) remain inferior to insect counterparts in ommatidial spatial arrangement, size distribution, visual field adaptability, and environmental perception. This work presents a tunable bionic CE with coaxial lens-on-lens (LoL) ommatidia, inspired by Sympetrum frequens, integrating a flexible polydimethylsiloxane (PDMS) LoL array with a microfluidic chip to achieve simultaneous bi-focal imaging. The LoL array was fabricated via femtosecond laser dual-modification of quartz glass, two-step wet etching, and soft lithography, yielding a concave template of approximately 2.6 mm². Integration with a microfluidic chamber enabled liquid-pressure modulation of CE configurations, producing a complete curved bi-focal plane that overcomes the limitations of single-focal-plane and regionalized nonuniform ommatidia CEs. Optical characterization confirmed stable focusing performance for both large and small ommatidia within their theoretical fields of view (FOVs). Cooperative bi-focal imaging was achieved by regulating FOV and relative positions of different LoL ommatidia through controlled injection of PDMS precursor. Large-FOV imaging and moving target monitoring were demonstrated, with reconstructed trajectories of triangular and dragonfly targets in 3D coordinates. The tunable CE with LoL ommatidia offers significant potential for particle image velocimetry, robotic vision, and virtual endoscopy, providing a scalable route to advanced micro-optical systems with adaptive visual field and depth perception.
Nano-Micro Letters•2025•DOI: 10.1007/s40820-025-01798-x
Creating strongly coupled heterostructures with favorable catalytic activities is crucial for promoting the performance of catalytic reactions, especially those involve multiple intermediates. Herein, we fabricated a strongly coupled platinum/molybdenum nitrides nanocluster heterostructure on nitrogen-doped reduced graphene oxide (Pt/Mo₂N–NrGO) for alkaline hydrogen evolution reaction. The well-defined Pt-containing Anderson-type polyoxometalates promote strong interfacial Pt–N–Mo bonding in Pt/Mo2N–NrGO, which exhibits a remarkably low overpotential, high mass activity, and exceptional long-term durability (> 500 h at 1500 mA cm⁻2) in an anion-exchange membrane water electrolyzer (AEMWE). Operando Raman spectroscopy and density functional theory reveal that pronounced electronic coupling at the Pt/Mo₂N cluster interface facilitates the catalytic decomposition of H2O through synergistic stabilization of intermediates (Pt–H* and Mo-OH*), thereby enhancing the kinetics of the rate-determining Volmer step. Techno-economic analysis indicates a levelized hydrogen production cost of $2.02 kg⁻1, meeting the US DOE targets. Our strategy presents a viable pathway to designing next-generation catalysts for industrial AEMWE for green hydrogen production.
Int. Journal of Mining Science and Technology (采矿与安全工程)•2025•DOI: 10.1016/j.ijmst.2025.01.006
Hydraulic fracture (HF) formed in rock significantly helps with the development of geo-energy and geo-resources. The HF formation condition was challenging to understand, with obscure rock micro-cracking mechanisms being a key factor. The rock micro-cracking mechanism under gradient pore water pressure was analyzed on the scale of mineral particles and it was combined with macroscopic boundary conditions of rock hydraulic fracturing, obtaining the propagation criterion of HF in rock based on the rock micro-cracking mechanism which was verified by experiment. The results show that the disturbed skeleton stress induced by the disturbance of gradient pore water pressure in rock equals the pore water pressure difference. The overall range of the defined mechanical shape factor a/b is around 1, but greater than 0.5. Under the combined influence of pore water pressure differences and macroscopic boundary stresses on the rock micro-cracking, micro-cracks form among rock mineral particles, micro-cracks connect to form micro-hydraulic fracture surfaces, and micro-hydraulic fracture surfaces open to form macro-hydraulic fractures. HF begins to form at the micro-cracking initiation pressure (MCIP), which was tested by keeping the HF tip near the initiation point. The theoretical value of MCIP calculated by the proposed propagation criterion is close to MCIP tested.
Int. Journal of Minerals, Metallurgy and Materials (矿物冶金与材料学报)•2025•DOI: 10.1007/s12613-024-2922-8
Three sets of MXene (Ti3C2Tx)@nano-Fe1Co0.8Ni1 composites with 15, 45, and 90 mg MXene were prepared by in-situ liquid-phase deposition to effectively investigate the impact of the relationship between MXene (Ti3C2Tx) and nano-Fe1Co0.8Ni1 magnetic particles on the electromagnetic absorption properties of the composites. The microstructure, static magnetic properties, and electromagnetic absorption performance of these composites were studied. Results indicate that the [email protected] composites were primarily composed of face-centered cubic crystal structure particles and MXene, with spherical Fe1Co0.8Ni1 particles uniformly distributed on the surface of the multilayered MXene. The alloy particles had an average particle size of approximately 100 nm and exhibited good dispersion without noticeable particle aggregation. With the increase in MXene content, the specific saturation magnetic and coercivity of the composite initially decreased and then increased, displaying typical soft magnetic properties. Compared with those of the Fe1Co0.8Ni1 magnetic alloy particles alone, MXene addition caused an increasing trend in the real and imaginary parts of the dielectric constant of the composite. Meanwhile, the real and imaginary parts of the magnetic permeability exhibit decreasing trend. With the increase in MXene addition, the material attenuation constant increased and the impedance matching decreased. The minimum reflection loss increased, and the maximum effective absorption bandwidth decreased. When the MXene addition was 90 mg, the composite exhibited a minimum reflection loss of −46.9 dB with a sample thickness of 1.1 mm and a maximum effective absorption bandwidth of 3.60 GHz with a sample thickness of 1.0 mm. The effective absorption bandwidth of the composites and their corresponding thicknesses showed a decreasing trend with the increase in MXene addition, reducing by 50% from 1.5 mm without MXene addition to 1 mm with 90 mg of MXene addition.