Guangfeng Shi

Titanium bipolar plates require surface modification to balance corrosion response and electrical contact resistance. Presynthesized TiN nanoparticles were deposited on Ti by ultrasonic-assisted electrophoretic deposition. In an illustrative comparison of one SEM field per condition, the ultrasound-assisted deposit (40 kHz) showed fewer dark defects: 0.45 versus 2.97% without ultrasound. Five local thickness measurements in one cross section gave 37.58 ± 1.81 μm. XRD supported retention of crystalline TiN, while XPS showed a chemically mixed surface consistent with the preparation history. Room-temperature polarization and impedance measurements in 0.5 mol L–1 H2SO4 + 2 mg L–1 F– showed a potential shift from approximately −0.45 to −0.35 V versus SCE and a higher impedance for the ultrasound-assisted specimen relative to the nonultrasound specimen. Initial gold-contact resistance was approximately 3.2 mΩ cm2 at 1.4 MPa, compared with 4.1 mΩ cm2 for bare Ti. These curves illustrate the tested specimens. Independently, calculations of ideal Ti/TiN contacts resolved registry- and termination-dependent electronic distributions and local Ti–N interactions. The study provides an experimental case for ultrasound-assisted particle assembly and a separate electronic reference for Ti/TiN contact design.

Optical and synthetic aperture radar (SAR) image matching is fundamental to numerous remote sensing applications. Although phase congruency-based methods have been widely adopted for this task, the structural features they extract remain inherently sensitive to speckle noise, which significantly degrades matching performance. To address this limitation, we propose a novel noise-robust multiscale structural feature (NMSF) method. Unlike existing relative total variation (RTV)-based approaches that modify the RTV model or rely on phase congruency, our framework employs the standard RTV model with a principled exponential scaling scheme to construct multiscale structural maps (MSM), effectively capturing salient structural information across multiple scales while suppressing noise and mitigating modality discrepancies. Building upon the MSM, we develop an MSM-ORB detector with non-maximal suppression to extract reliable and well-distributed keypoints. We further introduce a multilayer features of oriented gradient (MFOG) descriptor with a square grid nested architecture, which fundamentally differs from the log-polar structures used in prior methods and achieves multiscale integration without dimensional inflation. Extensive experiments on publicly available datasets demonstrate that NMSF consistently outperforms state-of-the-art approaches, delivering superior robustness and accuracy under nonlinear intensity variations, geometric distortions, and severe speckle noise.

As a typical hard-and-brittle material, single-crystal germanium is characterized by inferior surface integrity and suboptimal material removal efficiency when subjected to conventional single point diamond turning. In contrast, in-situ laser-assisted turning (LAT) has demonstrated superior performance in achieving smooth surface machining of single-crystal germanium. In this study, a novel diamond tool and laser-assisted heating method were developed, in which the laser beam is refracted at the rake face and cutting edge and undergoes total internal reflection (TIR) at the flank face, thereby enhancing laser utilization efficiency. The effect of laser power on temperature distribution during in-situ LAT was investigated through thermo-mechanic coupled finite element cutting simulations. Using surface roughness as the response variable, optimal machining parameters for in-situ LAT of single-crystal germanium were determined via response surface methodology: laser power of 10 W, spindle speed of 2492 rpm, feed rate of 1.64 μ m rev ^–1 , and depth of cut of 1.50 μ m. Under these optimized conditions, the predicted minimum surface roughness was 10.28 nm, representing a 67.54% reduction compared to the maximum experimental value.

This study addresses the issue of adhesive wear in diamond tools during laser in-situ assisted mechanical scratching. Based on Multiphysics simulation, it reveals the mechanisms by which different adhesive layer thicknesses affect the laser field distribution, intensity distribution, and propagation characteristics of the tool. During the laser-assisted scratching process, workpiece material tends to adhere to the tool surface and form adhesive layers with different thicknesses, and the adhesive layer thickness can be regarded as an important state parameter for characterizing the progression of adhesive wear. Based on COMSOL Multiphysics, tool models with different adhesive layer thicknesses were established, and coupled analyses of heat transfer, wave optics, and ray optics were systematically carried out. The results show that laser transmission through the tool induces significant temperature field evolution and thermal deformation, and the thermal load has an important effect on the structural integrity of the tool. After the laser enters the transparent diamond scratching tool, it is jointly affected by the tool geometry and the optical properties of the adhesive layer interface. Reflection, refraction, and interference occur inside the tool and near its surface, resulting in a non-uniform optical field distribution characterized by alternating localized enhancement and attenuation in space. The presence of an adhesive layer leads to asymmetric electric field distribution, enhanced local field intensity, and more complex processes of reflection, refraction, and scattering on the tool surface. With increasing adhesive layer thickness, the propagation paths of rays inside the tool become progressively disordered, energy dispersion is intensified, and the transmitted laser power density decreases significantly. This paper reveals the intrinsic relationship between the thickness of the adhesive layer and the distribution and propagation characteristics of the laser light field from the perspective of Multiphysics simulation, providing a theoretical basis and simulation foundation for characterizing the adhesive wear state of diamond scratching tools based on light intensity distribution and propagation response characteristics.

To clarify the effect of in situ laser heat input on the apparent indentation response of an AlSi1060 aluminium film/glass substrate system, an integrated in situ laser heating–instrumented indentation platform and a calibrated coupled thermo-mechanical finite element model were developed. Displacement-controlled indentation tests were conducted at depths of 0.5–5 μ m under laser powers of 0, 5, 10 and 15 W. Thermal-drift control measurements were performed under the same conditions, and the raw displacement signals were corrected before extracting load, hardness, energy and unloading-recovery parameters. With increasing laser power, the P – h curves shift downward and the peak load required to reach the same prescribed depth decreases continuously. At h _max = 5 μ m, P _max and hardness H decrease by approximately 44% and 45%, respectively. The experimentally defined softening coefficient λ shows no statistically significant depth dependence within the investigated range but decreases markedly with laser power, indicating that the load-level reduction is mainly governed by local heat-input intensity. Apparent Nix–Gao-type fitting shows that both H ₀ ,app and h *,app decrease with laser power; these parameters are interpreted as system-level descriptors rather than intrinsic properties of the aluminium film alone. Finite element results show that the high-stress region remains beneath the indenter, while the stress level needed to sustain the same indentation depth decreases with heat input. Energy decomposition confirms that plastic dissipation dominates under all conditions, with η _pl increasing slightly from 0.933 to 0.958 and R _e decreasing from 0.067 to 0.042. After unloading, indentation-derived residual depth increases, optical micrographs show clearer projected residual boundaries, and simulation-derived profiles indicate enhanced local pile-up. These results demonstrate that in situ laser heating reduces the apparent load-bearing resistance of the film/substrate system, suppresses unloading recovery and improves residual-shape retention.

Molecular dynamics simulations were conducted to investigate interfacial friction and plastic deformation during nanometric cutting of Fe–C alloys with micro-textured cubic boron nitride tools. A three-dimensional cutting model was established, including a conventional chamfered tool, a micro-textured tool, and micro-textured tools filled with graphene, carbon nanotubes, and molybdenum disulfide. The introduction of micro-textures alters the tool–chip contact configuration and reduces interfacial shear resistance, leading to a 22.3% decrease in steady-state tangential force and a reduction in friction coefficient from 2.19 to 1.59. Solid lubricant filling further regulates interfacial sliding and energy dissipation, with graphene showing the most significant effect. Dislocation analysis indicates that the plastic deformation of body-centered cubic Fe is dominated by 1/2〈111〉 dislocations. The presence of micro-textures and graphene suppresses the dislocation activity in the primary shear zone, thereby modifying the local plastic flow and interfacial friction behavior.

A molecular dynamics model for the electroplasticity-assisted nano-cutting of polycrystalline SiCp/Al has been developed, incorporating the electronic wind effect and Joule heating effect at the nanoscale. Through a comparison between conventional cutting and electroplasticity-assisted cutting processes in terms of material removal behavior, energy accumulation characteristics, cutting force, stress distribution, and crystal defect evolution patterns, the influence of the electroplastic effect on the plastic deformation of polycrystalline SiCp/Al composites has been investigated. The results demonstrate that electroplasticity-assisted cutting enhances the material removal rate, decreases the energy rise rate and cutting force, and expands the distribution range of amorphous atoms in the cutting region. Compared with conventional cutting, electroplasticity-assisted cutting achieves a 27.5% increase in the number of atoms removed, along with reductions in the resultant cutting force and its X-, Y-, and Z-direction components of 16.3%, 39.7%, 15.7%, and 17.2%, respectively. Under the influence of an electric current, the Joule heating effect raises the temperature of the material, resulting in a reduction in hardness. Simultaneously, the electron wind force acts upon dislocations, promoting dislocation movement and multiplication. The synergistic effect of the two enhances atomic-scale plastic flow, improving the overall plastic deformation capacity of the material. These findings clarify the role of the electroplastic effect in the plastic deformation of polycrystalline SiCp/Al composites, providing theoretical support for optimizing machining processes for SiCp/Al composites in industrial applications.