Three-dimensional UAV path planning necessitates strong global search capabilities due to its high-dimensional optimization nature. To address premature convergence and enhance local search efficiency in comparison to traditional DBO methods, this study proposes MSDBO, a multi-strategy fusion algorithm. The approach involves utilizing piecewise chaotic mapping to increase population diversity, integrating OOA for improved global exploration, and implementing a dynamic balance mechanism comprising Sigmoid convergence factors, adaptive t-distribution mutation, and dynamic weights. Additionally, simulated annealing is enhanced to achieve better convergence precision. Through systematic validation encompassing 21 benchmark functions, Wilcoxon tests, and CEC2021, MSDBO exhibits superior convergence accuracy and robustness when compared to seven other metaheuristic algorithms. Urban flight experiments further demonstrate MSDBO’s ability to generate smoother paths with a 7.5% lower optimal cost and a 31% reduced standard deviation than DBO. These findings confirm the efficacy of MSDBO in tackling UAV path planning challenges in complex scenarios through coordinated multi-stage optimization.

Lithium-ion batteries (LIBs) inevitably encounter abusive mechanical loading during engineering applications and result in mechanical deformation, internal short circuit, and even thermal runaway. A 18650 LIB under minor mechanical deformation is subjected to cyclic charge/discharge experiments in this study to analyze its aging behavior. Aging mechanism of the battery with minor deformation is qualitatively investigated through the incremental capacity analysis (ICA). ICA, a commonly used method for exploring degradation mechanism of LIBs, can transform flat voltage plateaus into peaks in the capacity increase curve (IC curve). Experimental data during the battery charging/discharging cycle can be used to calculate the IC curve, which can reflect the characteristics of electrochemical changes inside the battery. Results showed that the LIB suffers from deterioration in the state of health (SOH) in the entire charge/discharge cycle upon minor mechanical deformation. Possible explanations for the slight decrease in SOH with the increasing number of cycles in the early stages and the rapid decrease in the charge/discharge capacity in the late stages were provided. However, precise mechanisms for these phenomena require further detailed research. Moreover, damaged cells demonstrate considerably higher temperature increments than original ones. This temperature difference will increase if additional charging/discharging cycles are conducted. This research infers that additional metallic lithium deposits in damaged cells compared with the original ones cause serious exothermic reactions and lead to enhanced heat accumulation.

Aiming at the difficulty of defect detection caused by the low contrast between defects such as scratches, deformation and foreign bodies on the surface of parts and the background, and the defects are greatly affected by the surrounding light, an accurate recognition method of low contrast defects based on improved YOLOv7 is proposed. A fusion Mosaic and MixUP online data enhancement method is proposed to expand the training sample data. The GAM attention module is added to the backbone network to enhance the feature extraction ability of low contrast defects, and SIoU loss function is used to focus on the accuracy of the model to accelerate the convergence speed of the model, and the fast suspected defect location is realized based on multi-camera. After focusing on the suspected defect position, the defect features are enhanced and accurately identified by rotating the 6RSS mechanism. Experiments show that the SIoU-YOLOv7-GAM algorithm shows better performance than the original YOLOv7 algorithm, and the average accuracy and recall rate are increased by 2.92 % and 5.02 %, respectively. The proposed multi-camera focusing detection method has a high recognition accuracy for low-contrast defects on the surface, and can eliminate the problem of defect error recognition to achieve accurate detection of low-contrast defects on the surface of parts.

Straightening is an important process in the production and application of shafts, tubes, and various profiles. According to the springback theory of small curvature plane bending, the pure bending process and springback of in-plane curved beam with symmetrical section were analyzed, and the over-bend straightening theory was established. Based on this, the straightening mechanism of the existing over-bend straightening process was revealed; that is, a zigzag straightening moment was applied in the three-point multi-step straightening process to approximate the smooth curve of theoretical moment, while the multi-point one-time straightening technology was to discretize the theoretical curve using the broken line, so both of them needed a load correction coefficient to compensate the error between the actual load and theoretical calculation. In order to realize the complete loading of theoretical curve, a new technology of three-roll continuous straightening was further proposed and the experimental equipment for shafts and tubes was built. In order to match the characteristics of a pipe section, an accurate moment calculation equation was established. Three-roll continuous straightening experiments of the tube showed that the straightness of the straightened workpiece could be controlled within 1.5‰, which meets the standard requirements. Therefore, it is suggested that the over-bend straightening theory can predict the load required for straightening in-plane curved parts with any symmetrical cross-section, and the three-roller continuous straightening process is an efficient and highly accurate straightening technique.

Titanium (Ti)-based metallic biomaterials (MBs) are traditionally employed as mechanical supports and constraints in clinical practice, owing to their superb comprehensive mechanical properties, great corrosion resistance, and good biocompatibility. Recently, Ti-based MBs have emerged as promising candidates for antitumor applications. These developments focus on the functionalization of Ti-based MBs to inhibit tumor propagation and recurrence. This work systematically examines the antitumor approaches of Ti-based MBs and categorizes them into physical and chemical approaches. Physical strategies, such as the photothermal and photocatalytic techniques, are usually related to material-specific properties. Chemical approaches often employ controlled local drug delivery (LDD) systems. Ti-based LDD systems enable the targeted release of chemotherapeutics, metal ions, or immunomodulatory agents at tumor sites. This review highlights the efficacy of these surface-functionalized Ti-based MBs against diverse tumors. Additionally, the challenges and prospects of antitumor Ti-based MBs are also discussed.