With the aid of plane strain assumption, classical bending theory without shear deformation, as well as linearized drift-diffusion current density model for mobile carriers, a theoretical model of magneto-thermo-mechanical coupling for multiferroic flexoelectric piezoelectric semiconductor (PS) device with surface effect is established based on nonlinear magnetostrictive constitutive model for giant magnetostrictive material Terfenol-D, phenomenological theory for PS, and zeroth-order plate equations related to coupled extensional and flexural deformations with surface effect, strain gradient, and flexoelectricity. After correctness and validity analysis of theoretical model developed, the systematic numerical analysises and discussions are carried out sequentially with emphasis on screening effect of mobile carriers, size-dependent characteristic and critical thickness induced via surface effect, strain gradient, flexoelectronics-related electronic regulation, and nonlinear active manipulation mechanism and evolution law about multi-physical fields. Numerical results indicate that a comparatively small initial state electron (hole) doping concentration can effectively improve magnetoelectric (ME) coupling effect, which is unfavorable for enhancing strain gradient and electric polarization. At nanoscale, ME coupling effect becomes stronger because of a stronger surface effect corresponds to a larger surface thermal stress modulus and surface piezomagnetic constant. When thickness of multiferroic flexoelectric PS device decreases to its critical size, the size-dependent characteristic of deformation-polarization-carrier coupling fields caused via flexoelectricity is very evident and must be fully considered. This research is of great significance for understanding flexoelectronics-related nonlinear active manipulation mechanism about mobile electron and hole transport characteristics in controllable giant magnetostrictive material exemplified by Terfenol-D based flexoelectric PS devices.

In this paper, a nonlinear magneto-thermo-mechanical coupling theoretical model related to the coupled extensional and flexural deformation working modes of controllable heterogeneous PN junction devices is established, and the screening effect caused by the doping levels of the initial mobile carrier concentrations, the surface effect and critical thickness of the average electric field, and the active manipulation mechanism and evolution law for the deformation-polarization-carrier coupling fields are investigated. The results show that a relatively moderate doping level can effectively improve the transport behaviors and distribution characteristics of the electrons and holes in the PN junction. When the thickness of the PN junction device is reduced to a critical value, the size-dependent behavior caused by the surface effect owing to the average electric field difference is obvious. The working performance of the controllable giant magnetostrictive Terfenol-D based heterogeneous PN junction device can be improved evidently when the Terfenol-D layers of the laminated nanoplate devive are subjected to the changing operating temperature, applied external magnetic field, or pre-stress stimuli. These findings can provide effective guidance for the explanation of the nonlinear magneto-mechanical-thermo coupling active manipulation mechanism for induced deformation-polarization-carrier coupling fields, as well as the experimental design of Terfenol-D based heterogeneous PN junction nanodevices.

With the continuous increase in performance requirements for aero-engines, film cooling holes (FCHs) play a critical role in enhancing engine efficiency. To address the challenge of machining large-aspect-ratio FCHs in turbine blades, this study establishes a theoretical model of the femtosecond laser–DD6 alloy interaction based on the material point method (MPM). The evolution of hole-depth saturation under femtosecond laser irradiation is systematically analyzed, revealing that hindered material removal in deep holes results from a periodic accumulation–ejection–accumulation cycle of particles. Real-time observation of particle dynamics during hole penetration was conducted using a CCD camera. When the hole depth reaches saturation, plasma within the holes exhibits four characteristic behaviors: energy transfer and reflection coupling, a piston effect with shock waves, in-hole zoning, and stabilization. During the chip removal stage, the ejected particles pass through four states: initial penetration, internal ejection, stable emission, and re-ignition with splashing. Based on these insights, a dynamic, monitored machining strategy was developed. Using this method, large-aspect-ratio FCHs with an inlet diameter of 360 μm and an aspect ratio of 22:1, free of recast layers, were successfully fabricated on 8 mm-thick nickel-based alloy substrates.

The development of third-generation semiconductor technology has led to a continual increase in the power density of electronic devices, making thermal management a critical bottleneck for device reliability. Diamond, known for its exceptional thermal conductivity, has shown great potential in chip-level heat dissipation and metal matrix composites. However, the thermal transport efficiency at metal/diamond interfaces is constrained by the mismatch between their primary heat carriers. In this work, we systematically investigate the role of a graphene interlayer in modulating thermal transport across the Au/diamond interface using the two-temperature model molecular dynamics (TTM-MD) simulation. Our results demonstrate that the introduction of a graphene interlayer can reduce the thermal boundary resistance (TBR) by up to 27.2%. Through phonon density of states (PDOS) and spectral heat current (SHC) analysis, we reveal a synergistic mechanism between interface morphology engineering and graphene-mediated phonon bridging: sinusoidal structure (both 2D and 3D) fully exploits the phonon-bridging capability of graphene, effectively mitigating the phonon spectrum mismatch between metal and diamond, while surface roughness extends phonon transport channels into mid- and low-frequency regimes. It is noteworthy that although the 3D sinusoidal structure further broadens the phonon transport pathways, the strong phonon localization induced by its complex geometry in the low-frequency range counteracts this benefit, leading to a slightly higher TBR than that of the 2D structure. This study highlights the importance of balancing the broadening of phonon transport channels against the suppression of phonon localization in interface design, providing theoretical insights and practical strategies for optimizing thermal management at metal/diamond interfaces.

Thermal management is critical for high-power GaN devices. Integrating GaN with diamond via a metal interlayer is a promising solution, but the role of the metal microstructure in interfacial thermal transport remains unclear. Here, we systematically investigate the effects of metal composition, grain structure, and interdiffusion on thermal transport across GaN/metal/diamond interfaces using molecular dynamics simulations and experiments. We find that Ti acts as a "phonon bridge" that enhances the phonon density of states (PDOS) overlap between the metal layer and substrates. A non-monotonic relationship between overlap energy (E-overlap) and thermal boundary resistance (TBR) distribution highlights the importance of phonon localization. Grain refinement and interdiffusion promote atomic mixing, alter phonon localization, and redistribute TBR: TBRmetal/GaN decreases while TBRdiamond/metal increases, with larger TBR differences under greater disorder. Experiments reveal interdiffusion and recrystallization in the metal interlayer; time-domain thermo-reflectance (TDTR) measurements yield a total TBR of similar to 20 m(2) K GW(-)(1). These results demonstrate that interfacial thermal transport is governed by phonon mode matching and phonon localization, providing guidance for metal interlayer design in the thermal management of high-power electronics.

The difficult-to-machine characteristics of Titanium alloys pose significant challenges to achieving high-efficiency and high-precision microstructural fabrication in these materials. In the present study, a coaxial hybrid laser-electrochemical machining method was proposed, which innovatively combined a spherical-end optical fiber with focusing capability and a tubular metal electrode. The material removal mechanism of TC4 alloy (Ti-6Al-4V) under the combined action of laser and electrochemical energy fields was investigated. In addition to increasing the electrolyte conductivity, the laser also enhanced the current efficiency of the hybrid process. At a laser power of 40 W, the current efficiency of the hybrid machining increased by 23.9%. The effects of machining voltage and laser power on the depth, width, and shape of the machined groove structures were examined. It was observed that the groove width was minimized under laser-assisted electrochemical machining. The groove depth was influenced by the laser power. When the laser power exceeded 20 W, the groove depth was governed by the laser machining depth and varied only slightly with changes in machining voltage. When the laser power was below 20 W, the groove depth resulted from the combined action of laser and electrochemical machining. Furthermore, the maximum material removal rate and the flatness-preserving removal parameters within the investigated process window were identified. Finally, by optimizing the tool electrode horizontal feed rate to integrate high-efficiency removal with surface finishing, a U-shaped groove structure was successfully obtained, featuring a bottom surface roughness of 4.1 mu m, free of laser machining marks and without molten residue.

This study addresses efficiency limitations in laser hybrid electrochemical machining (LECM) of high aspect-ratio micro holes in TC4 titanium alloy. Through morphological and EDS analysis of hole bottoms, it is identified that machining rate is constrained by: nonuniform electrochemical dissolution in Area III, and poor waste electrolyte renewal causing precipitate and gas accumulation. A synergistic strategy combining the insulation layer retraction and high-temperature electrolyte to enhance the machining efficiency was firstly proposed. Finite element simulations reveal that using high-temperature electrolyte enhances current density and dissolution homogeneity, while tubular electrodes with insulation layer retraction improve discharge flow velocity and electric field distribution. Experimental validation optimized the retraction distance and electrolyte temperature which could improve machining rate and ensure hole accuracy. Ultimately, the holes of 75 mm deep were fabricated at 5.1 mm/min employing above two techniques for the first time, representing an enhancement of 112.5% on machining efficiency. And the maximum processing speed fabricating shallow holes reaches 7 mm/min which is increased by 16.7% compared to conventional LECM. Synergistic use of high temperature electrolytes and insulation layer retraction effectively breaking through the hole machining efficiency ceiling of LECM, furnishing a new method for micro hole fabrication in aero-engine components.

This study investigates the precision processing of flexible thin film conformal antennas for use in aerospace and microelectronics applications. Current methods for processing these types of antennas have different degrees of defects, but the use of a UV-nanosecond laser offers several advantages, such as high photon energy, non-contact processing, and a small heat-affected zone. In this study, we conducted a technical analysis of the circuit structure of radar flexible thin film antennas through UV-nanosecond laser direct writing and achieved controlled processing of large-format radar flexible thin film conformal antennas. We built a UV-nanosecond laser processing system platform and carried out studies on both the single-line removal process and small-format fine removal. The surface roughness of polyimide was successfully reduced to 0.55 & micro;m, the contour accuracy was controlled to within 10 & micro;m, and high-quality processing of complex patterns was achieved. Based on these findings, the large-format flexible thin-film antenna stitching process was further investigated, and the contour error of large-format flexible thin-film antennas was successfully controlled within +/- 8 & micro;m, the stitching error within 2 & micro;m, and the surface roughness within 0.24 & micro;m. Furthermore, effective copper removal was achieved in the designed non-conductive regions. Ultimately, the proposed processing method enables the fabrication of large-format flexible film antennas with low surface roughness, good surface consistency, and no obvious stitching marks.

Laser-induced periodic surface structures (LIPSSs) enable the flexible fabrication of subwavelength patterns on most solid surfaces. However, their applications are constrained by inadequate control over feature depth and the emergence of defect layers within the crystalline material. This paper proposes a hybrid method that combines LIPSSs with inductively coupled plasma (ICP) etching to fabricate defect-free, ultra-high aspect ratio grating structures with adjustable depths. The formation conditions of laser-induced periodic oxidation were determined to involve the generation of ablated silicon LIPSSs, which subsequently become coated with a layer of SiO2. The thickness of the oxide layer is systematically controlled, varying from 1.03 to 2.63 & micro;m, corresponding to increases in pulse energy and scanning speed. Subsequent ICP etching experiments reveal that the as-formed periodic oxide layer acts as an effective mask. Nevertheless, the periodic oxide layer is also consumed during the silicon ICP etching process. Consequently, the maximum achievable depth of the LIPSSs reaches 1730 nm, corresponding to a maximum aspect ratio of 7.86. Furthermore, ICP etching effectively removes the laser-induced defect layer. This hybrid method offers a viable approach for fabricating silicon nanostructures.

Microgroove structures were directly fabricated on the inner surface of the infrared window, microgroove structures are directly fabricated using a femtosecond laser to meet the demands of a highly complex service environment and system-integrated manufacturing. However, it is essential to maintain the system's initial high transmittance service performance needs to be ensured at the same time. In this study, we employed the finite-difference time-domain (FDTD) method to establish a simulation model for the transmittance performance of surface microstructures on MgF2 ceramic materials. We analyzed the transmittance and electric field effects of the surface microgroove structure parameters on MgF2 surfaces within the mid-infrared (IR) wavelength range of 3 to 7 mu m. Then, using femtosecond laser processing, a large-area microgroove array structure was fabricated on the MgF2 window surface using femtosecond laser processing. Within the mid-infrared operating wavelength region, the results demonstrated that the femtosecond laser-fabricated microstructure arrays made with femtosecond laser exhibit excellent transmittance performance, and the theoretical modeling effectively guides experimental processing. This study establishes a technical foundation for the theoretical calculation and highperformance fabrication of surface microstructures on ceramic windows used in aircraft infrared detection systems.

Silica glass, known for its excellent chemical stability, physical properties, and biocompatibility, is an ideal material for microfluidic chips. However, its brittle nature makes precise microfabrication challenging. Femtosecond laser technology, with its high processing precision and minimal thermal impact, provides an effective solution to this issue. Single-phase liquid flow in microfluidic chips is widely used in applications such as biological monitoring and chemical analysis, where flow characteristics, including flow rate and pressure drop, have a significant influence on system performance. Therefore, precise control of liquid flow is essential. In this work, a passive control method for single-phase liquid flow based on the microchannel cross-sectional geometry is proposed. First, numerical simulations were carried out to investigate the influence of different microchannel cross-sectional shapes on liquid flow behavior. Under the same flow rate, the results indicate that V-shaped microchannels exhibit the highest average flow velocity, followed by trapezoidal and rectangular channels, and the pressure drop shows the same trend. Subsequently, femtosecond laser processing was employed to etch microchannels, where the channel geometry was tailored by adjusting the processing parameters. After chip packaging, the liquid flow behavior was experimentally characterized. The experimental results show that the trends of flow velocity and pressure drop are in good agreement with the simulation predictions, with an average deviation of approximately 10%. These results confirm that passive regulation of liquid flow can be effectively achieved by modifying the microchannel cross-sectional shape. This approach provides a practical strategy for liquid flow regulation and femtosecond-laser-fabricated microfluidic chips, with potential applications in biological monitoring, chemical analysis, and related fields.

Silica glass, renowned for its exceptional physical, chemical, and biocompatible properties, serves as a critical substrate for microfluidic devices. However, its inherent hardness and brittleness present significant challenges for achieving precise and efficient fabrication. Although femtosecond lasers offer remarkable advantages in precision machining, achieving simultaneous enhancements in machining quality and processing efficiency remains a complex challenge. This study introduces a data-driven framework that integrates a Gaussian Process Regression (GPR) model with an improved Non-dominated Sorting Genetic Algorithm II (NSGA-II) for the multi-objective optimization of femtosecond laser-based microchannel fabrication. The GPR model systematically captures the relationships between processing parameters, surface roughness (Sa), and material removal rate (MRR), effectively addressing nonlinear interactions during multi-pass scanning. The enhanced NSGA-II algorithm incorporates adaptive parameter adjustments and improved population diversity to robustly explore the solution space, enabling the identification of optimal trade-offs between surface quality and processing efficiency. Experimental validation of the optimization results reveals strong agreement between predicted and actual outcomes, demonstrating the framework's effectiveness in simultaneously minimizing surface roughness and maximizing material removal rate. This work underscores the potential of combining GPR and NSGA-II to optimize femtosecond laser micromachining, offering a robust methodology to significantly improve both the quality and efficiency of microfabrication processes.

Focusing optical elements are susceptible to performance degradation in harsh environments caused by fog, ice, and dust. Existing protective solutions struggle to balance high light transmittance with effective anti-icing and self-cleaning properties. Here, taking inspiration from asymmetric structures observed in nature, a focusing optical element with surface-integrated bent micropillar arrays is proposed, which exhibits antifogging, antifouling, and anti-icing capabilities. The focusing element is fabricated through a combination of femtosecond-laser processing, soft lithography, and pneumatic pressure-assisted molding. The bending angle of the micropillar array can be precisely regulated by adjusting the femtosecond-laser parameters. The results demonstrate that the bent micropillar arrays facilitates directional droplet rebound and imparts self-cleaning and antifogging functionalities to the surface. Additionally, it markedly decreases ice adhesion strength. Under simulated conditions characterized by pollution, elevated humidity, and low temperature, the focusing element sustains a high visible light transmittance exceeding 86%, while exhibiting outstanding multifunctional protective capabilities and stability. This work presents a design paradigm for the stable operation of optical devices in challenging environments.

TC4 titanium alloys are increasingly utilized in industrial applications due to their excellent mechanical and physical properties. Laser-electrolytic hybrid machining, as an advanced multi-energy-field manufacturing technology, represents a promising approach for enhancing the machining efficiency of TC4 titanium alloys. However, the formation of oxide layers during hybrid processing degrades the surface quality. Therefore, this study proposes a laser-electrolytic hybrid machining method incorporating a tool electrode with an adjustable tilt angle. By adjusting the tilt angle of the tool electrode, the evacuation of machining products from the machining gap and the distribution of current density are optimized, thereby improving both the material removal rate (MRR) and surface roughness. Forward and reverse machining experiments were conducted under different tilt angles. The results indicate that, compared with vertical machining, inclined machining achieves a maximum increase of 112% in MRR. Surface composition analyses reveal that reverse-inclined machining reduces the oxygen content on the machined surface, thereby mitigating oxidation effects. Furthermore, this approach achieves a maximum reduction of 29% in surface roughness. Overall, the proposed approach enhances the flexibility and performance of laser-electrolytic hybrid machining and demonstrates its feasibility for highquality and high-efficiency processing of TC4 titanium alloys.

The femtosecond laser (fs-laser) slicing technique, owing to its superior efficiency and reduced loss, is anticipated to supplant wire sawing as the predominant method for slicing silicon carbide (SiC). Nevertheless, the current ultrashort laser slicing techniques are focused on a combination of high laser fluence, exceeding the laser ablation threshold, and a sub-micron depth of field attributable to the objective lens, leading to thicker modified layers. This paper introduces an innovative way for producing a thinner modified layer in 4H-SiC, transitioning from nanodeformation to decomposition. To begin with, experimental results demonstrate that nanodeformation persists in laser-treated regions and can achieve decomposition via the optical near-field enhancement effect. Surface decomposition can be divided into four stages: nanoholes, LSFL, HSFL, and deep pits. In addition, the lower laser fluences, which facilitate the creation of nanoholes and nano-ripples, are appropriate for the generation of modified layers in 4H-SiC. The new method offers the advantages of a thinner deformation zone and fewer defects. On this basis, a modified zone of 7.34 mu m is created at a depth of 200 mu m under the surface of 4H-SiC using a lens with a 30 mm focal length. Notably, the thickness of the modified layer could be controlled to 2.90 mu m, with negligible stress-affected areas around the modified layer. It is worth noting that the modified layers fabricated by reducing the laser fluence have the dual effect of making the modified unit thinner and improving spatial consistency to a significant degree. This novel technique for producing modified layers in SiC can independently enhance accuracy and is also applicable to laser processing with cylindrical lenses, significantly improving the efficiency of the laser slicing technique.

Achieving superhydrophobic surfaces with high optical transparency and durability remains a key challenge for optical and fluidic applications. This study investigates the formation mechanism of femtosecond laser-induced microgroove arrays and compares three double-pulse configurations-low-high, equal-equal, and high-low energy sequences-with the conventional single-pulse mode for generating hierarchical micro/nanostructures. Among them, the low-high sequence (Type 1) produced the most uniform and defined structures by modulating free-electron dynamics and enabling homogeneous energy deposition, stabilizing a Cassie-Baxter wetting regime. A 1.5 & times; 1.5 cm(2) transparent superhydrophobic sample was fabricated in 75 s using a single scan, maskless process. After applying a fluorocarbon plasma treatment (C4F8), the Type 1 surface showed a water contact angle of 154.5 degrees and high transmittance (>88%) in the 300-800 nm range. XPS revealed the highest CF2/CF3 ratio on this surface, correlating with enhanced hydrophobicity. The surface also demonstrated excellent durability against compression, tape delamination, aging, water jets, thermal cycling, and chemical corrosion. This work presents a rapid and scalable laser-based method for fabricating large-area, durable, and transparent superhydrophobic glass surfaces for potential use in optical windows, self-cleaning coatings, microfluidics, and smart devices.

With the fast development and application of metal-ion batteries in electronic devices, electric vehicles, and smart grids, the demand for high-performance batteries is dramatically increasing. Three-dimensional (3D) electrodes have emerged as an effective strategy to improve the performance of various batteries. As an emerging precision manufacturing technology, laser processing has recently been demonstrated to offer significant advantages in fabricating 3D electrodes and tailoring material and structural properties. In this review, the principles of designing 3D electrodes are comprehensively analyzed first from the perspective of enhancing overall battery performance. Based on these targeted 3D structures, the platform and techniques of laser processing are systematically introduced, and the typical methods-including laser texturing, laser drilling, laser cutting, and laser-induced modification-are demonstrated. As a result, the review highlights performance enhancements in practical capacity, rate capability, cycling stability, and operation under extreme conditions. Moreover, the compatibility of laser processing with current battery manufacturing technologies is discussed, and the potential for high-efficiency, large-scale fabrication of 3D electrodes using laser techniques is envisaged. Finally, the opportunities and challenges for laser processing of 3D electrodes are summarized, providing a systematic understanding of this emerging technology. This review is anticipated to guide both fundamental research and industrial applications of laser-processed high-performance 3D electrodes.

The development of high-performance, flexible conductive coating with enhanced electrical conductivity, thermal stability, and mechanical durability remains a critical challenge in advanced materials and coating technologies. This study investigates the effect of nanosecond laser scanning line spacing on the structural, morphological, thermal, mechanical, and electrical properties of epoxy/multiwalled carbon nanotube (Ep-MWCNT) coatings deposited on polyethylene terephthalate (PET) substrates. Raman analysis revealed a non-linear defect evolution, with the lowest defect density (ID/IG = 0.623) achieved at an optimal line spacing of 4 mu m, indicating effective defect healing and enhanced graphitic ordering. SEM and HR-TEM observations confirmed improved nanotube alignment, interconnectivity, and stronger interfacial bonding after laser irradiation, while excessive spacing led to nanotube agglomeration and structural degradation. XRD results demonstrated increased crystallinity and graphitization, evidenced by a sharp (002) peak at 26 degrees in laser-treated samples. Thermogravimetric analysis showed a remarkable enhancement in thermal stability, with the maximum degradation temperature shifting from 456 degrees C (pure PET) to 852 degrees C (after laser treatment of Ep-MWCNT/PET composite. Dynamic mechanical analysis revealed significant improvements in storage modulus and reduced damping behavior, indicating enhanced stiffness and interfacial constraint. Electrically, the optimized coating (4 mu m) exhibited the lowest sheet resistance 218 Omega/sq. and improved bending stability, with consistent cyclic sensing performance and reduced signal fluctuation. Furthermore, laser processing enhanced flexural strength and promoted dense, uniform morphology after repeated bending. FTIR analysis confirmed laser-induced chemical modifications and stronger matrix-nanotube interactions. Taken together, nanosecond laser tuning provides an effective strategy for defect healing, network optimization, and multifunctional performance enhancement of Ep-MWCNT coatings on flexible PET substrates for advanced organic coating and flexible electronic applications.

Developing advanced energy-storage materials requires efficient strategies to navigate the rapidly expanding compositional space beyond conventional trial-and-error optimization. However, rational discovery of multielement cathode compositions remains challenging due to the complexity of composition–structure–property relationships. Here, a knowledge-guided artificial intelligence framework integrating semantic mining, knowledge-graph reasoning, and high-throughput computational screening was developed to accelerate the discovery of complex cathode compositions. Analysis of a MatSciBERT-processed literature corpus using five normalized evaluation metrics identified vanadium-based polyanionic compounds as a promising platform under the adopted criteria. For Na3V2(PO4)2F2O (NVPFO), cross-material knowledge-graph analysis suggested Ni, Cr, Al, Mg, and Cu as candidate dopants. More than 9,000 configurations were subsequently screened using predicted formation energy, lattice distortion, and MBVGNN-based structural embeddings, revealing a favorable compositional region containing 4–6 dopant species and 1–10% total V-site substitution. Guided by these results, equimolar five-element compositions were synthesized, among which NVPFO/HE-0.02, corresponding to 5.0% total V-site substitution, exhibited the best overall performance. Compared with pristine NVPFO, its charge-transfer resistance decreased from 191.08 to 67.98 Ω, while its EIS-derived apparent Na+ diffusion coefficient increased by approximately one order of magnitude to 6.54 × 10-11 cm2 s-1. It retained approximately 75% of its initial capacity after 1,500 half-cell cycles at 2 C and 90% after 200 full-cell cycles at 1 C. This work establishes a transferable AI-guided screening-to-experiment paradigm for designing compositionally complex energy materials, demonstrating how scientific knowledge and computational intelligence can be integrated to accelerate next-generation cathode discovery.