To address the delamination failure issue in composite laminates caused by interlaminar stress concentration during supersonic flight，a novel sandwich functionally graded material （FGM） panel structure was proposed. First，the nonlinear geometric relationship of the sandwich FGM panel was formulated based on the Kirchhoff thin panel theory and the von Kármán large deformation theory. The nonlinear aerodynamic forces acting on the sandwich FGM panel were simulated using the third-order piston theory. The Hamilton principle was employed to derive the differential equations of motion for the sandwich FGM panel during supersonic flight. Subsequently，the Galerkin method was introduced to discretize these differential equations of motion spatially in both the streamwise and spanwise directions，yielding the corresponding system of ordinary differential equations. Finally，the dynamic response of the sandwich FGM panel was obtained by solving the derived ordinary differential equations using the Runge-Kutta method. The results indicate that，for a constant thickness of the sandwich core，a smaller gradient index n of the core material leads to a higher flutter critical dynamic pressure； When the gradient index n of the sandwich core is less than 1.0，the flutter critical dynamic pressure exhibits a monotonic increase as the thickness ratio of the sandwich core rises； Furthermore，as dimensionless dynamic pressure increases，the motion of the sandwich FGM panel transitions progressively from static stability to limit cycle oscillation.
To investigate the effect of polyurethane coating on the impact resistance of honeycomb sandwich structures， the impact response of composite sandwich structures with polyurethane coating applied to the inner walls of honeycomb cores under low-velocity impact conditions was analyzed.Based on the validated numerical model， a numerical analysis was performed to examine the low-velocity impact behavior of composite sandwich panels with varying coating thicknesses. Multiple indicators were employed to analyze the influence of coating thickness on the impact resistance of the composite sandwich panels. The results indicate that the honeycomb sandwich structure with a 0.5 mm thick coating on the inner walls exhibits an 11.11% reduction in the honeycomb core indentation depth and an 11.98% decrease in the indentation diameter along the impact direction. This method effectively enhances the impact resistance of honeycomb sandwich structures.
To solve the problems of cracking， wrinkling， and low precision in aluminum alloy sheet metal parts formed at room temperature， and to achieve low-cost， high-precision forming of fairing components， a study was conducted on deep stretching and pressing forming processes of thin-walled， complex structural components made of low-plasticity， low-strength 2A11 aluminum alloy at room temperature. By combining field experiments and sheet metal forming principles， an analysis of the rubber pad forming process and steel die pressing forming for an aluminum alloy fairing with a wall thickness of 1.0—2.0 mm and a stretching ratio of 0.62 was performed. Through segmented forming and iterative parameter optimization， the influence of parameters such as stretching speed， pressurization rate， and lubrication conditions on the quality of the stretching process was investigated. The impact of the quenching process on the aluminum alloy pressing forming process was studied through heat treatment experiments. This research successfully achieved deep stretching forming of the aluminum alloy fairing with a wall thickness of 1.0—2.0 mm at room temperature， effectively suppressing wrinkling and cracking. Furthermore， the problem of cracking in the stiffeners during pressing was resolved by optimizing the solution heat treatment parameters （temperature： 495—500 °C， time： 35—40 min）. The results indicate that rubber pad forming combined with segmented parameter optimization significantly improves the forming quality of thin-walled aluminum alloy components， and precise control of the quenching process is key to achieving defect-free pressing of the fairing’s stiffener surfaces.
The prediction of creep life for turbine blade relies on simulated blade temperature and stress data. However，simulations often simplify the entire turbine disk to a single blade，leading to inaccurate results. In order to investigate the validity of simplified single-blade models and enhance the accuracy of blade creep life prediction，a study on the creep life of turbine blades based on full-scale simulation method was conducted. First，full-scale simulation method for the turbine disk and a simplified single-blade model were established. Then，the blade temperature and maximum principal stress were calculated using the hybrid thermal-fluid-solid coupling method. Finally，the comprehensive equation of thermal strength parameters was employed to predict the creep life of the blade. The results indicate that the relative error in temperature between the single-blade model and the full-scale model does not exceed 2%； the relative error in maximum principal stress between the two is within 8%； however，the relative error in prediction of creep life between them reaches as high as 712.93%. The single-blade model predicts lower temperatures and maximum principal stresses，resulting in a significantly overestimated creep life. These findings demonstrate the necessity of employing a full-scale model to analyze the creep life of turbine blades and lay a foundation for the accurate prediction of their creep life.
In order to measure the infrared radiance of low-infrared-emittance films and explore the influence of temperature， distance and viewing angle on the detection results，the theoretical relationship between the temperature ratio coefficient and infrared emittance was demonstrated. A testing system that could be compatible with multiple samples simultaneously was constructed. The temperature ratio coefficients of the composite films within the temperature range of 773—1 023 K were tested at four angles with 0°， 15°， 30°， 45° and three distances with 0.8 m，1.2 m，1.6 m， respectively. The influence of detection temperature， distance and viewing angle on the temperature ratio coefficient of the samples was analyzed. The results show that within the tested temperature range，as the temperature increases， the temperature ratio coefficient of the samples gradually decreases； in terms of the tested distances， the temperature ratio coefficient of the samples at each position at 0.8 m is higher than that at 1.2 m and 1.6 m； in terms of the tested angles， the temperature ratio coefficients of the edge samples at 30° and 45° are significantly higher than those at 0° and 15°， and this gap increases with the increase of the testing temperature. The temperature ratio coefficients of the non-edge samples remain almost unchanged within the four tested angles. The research results of this paper lay a foundation for the subsequent research on the surface infrared emittance of multi-layer composite films.
To ensure grasping stability， prevent object slippage， and avoid structural damage， three common grasping models were established for a three-fingered robotic hand， and the critical force during the robotic finger grasping process was accurately solved. In the case of the design of the robot hand and the ideal physical assumption of the object to be grasped， through the force analysis in mechanics， the constraints of the critical force of the robot finger grasping problem were obtained according to the static equilibrium equation， and the optimization model of the critical force of the robot finger grasping was further given. Firstly， the KKT condition was written according to the optimization model， and then the NR function was used to transform it into a smooth equation system， and the value function was further introduced to transform the KKT condition into an unconstrained optimization problem. The dynamic equation system was constructed， and the stability of the dynamic equation system was analyzed， and the relationship between the solution of the dynamic equation system and the solution of the optimization problem was used to solve the critical force problem of robot finger grasping. Finally， a numerical experiment was conducted to verify the effectiveness of the dynamical equation system method.
In order to deeply investigate the long-term aging thermal stability of the GH4706 alloy used for turbine discs， the microstructure and mechanical properties of GH4706 alloy were analyzed by OM and SEM as well as tensile，endurance and impact tests under temperature-stress coupling （650 ℃- 300 MPa）. The results show that the strength，plasticity，durability and impact toughness of GH4706 alloy decrease with the increase of aging time，regardless of single temperature field or temperature-stress coupling field. However，the rupture life of GH4706 alloy under temperature-stress coupling field is much higher than that under single temperature field after 3 000 h long-term aging. The reason is that the γ' phase in the alloy under single temperature field is coarsened and dissolved. γ' phase changed from a fine disk to a long strip，resulting in a decline in the intracrystalline strengthening. The η phase precipitates at the grain boundary in a short rod-like form at the initial stage，and then coarsened to a needle-like or lamellar shape with the increase of precipitation time，which will weaken the grain boundary. η phase precipitation is inhibited by temperature-stress coupling field，and the distribution of η phase is cellular in the grain boundary，which plays a strengthening role in the grain boundary and is conducive to improving the high temperature durability.
To enhance the output performance of solid oxide fuel cell （SOFC） in the intermediate-to-low temperature range （800—350 ℃），undoped Ba2In2O5 was applied for the first time to SOFC power generation units， and the effect of this special layered structure on the electrochemical performance of the cells was systematically investigated.Experimental results demonstrate that the layered structure provides ideal channels for synergistic and efficient transport of oxygen ions and protons. The SOFC employing this material as electrolyte achieved a remarkable power density of 567 mW·cm-2 at 550 ℃ while maintaining effective output performance even at 150 ℃. Material characterization revealed dual oxygen ion-proton conductivity above 450 ℃， with predominant proton conduction in the low-temperature regime below 450 ℃.Through XPS and in situ Raman spectroscopy analyses， the formation of intrinsic oxygen vacancies under elevated temperatures was observed， with their impact on ionic conduction properties thoroughly investigated. It was established that the distinctive brownmillerite structure of BIO enables its exceptional performance as a medium-low temperature SOFC electrolyte material， providing a promising candidate material for advancing low-temperature operation of SOFCs.
To address the problem of disconnection between equipment functions and user needs in the context of snow accumulation in urban alleys and streets in northern winters， a functionally optimized small-scale snow removal device was designed by integrating the AHP-QFD-FBS model. The method involved investigating user needs， establishing a user needs analysis model using analytic hierarchy process （AHP）， and calculating demand weights. The weights of user demands were introduced into the quality function deployment （QFD） quality house model to convert them into design demand weights. The function behavior structure （FBS） model was used for structured mapping of design requirements to form the final design solution. The results of the design verification of small-scale snow removal equipment show that the AHP-QFD-FBS model effectively guided the innovative design of the equipment， especially in enhancing the responsiveness of the design to user needs. It also successfully improves the equipment's snow treatment efficiency. This method not only improves snow removal efficiency， but also reduces mechanical losses and user operational complexity， enhancing overall user satisfaction.
In order to improve the accuracy and efficiency of fire monitoring in complex enviroments， an improved YOLOv8n model named YOLOv8n-MAAI for fire detection was proposed. Firstly，by incorporating a multi-head self-attention （MHSA） mechanism into the backbone network， the model’s ability to handle complex scenarios was enhanced， improving detection accuracy. Furthermore， the ADown module from YOLOv9 was integrated into the YOLOv8 architecture， reducing computational complexity through a lightweight design. The adaptive spatial feature fusion （ASFF） mechanism was introduced to form a new Detect_ASFF detection header， filtering conflicting information and improving feature scale invariance. Finally， the Inner-MPDIoU loss function was employed to optimize the training process， enhancing regression accuracy and accelerating model convergence. Experimental results demonstrate that YOLOv8n-MAAI achieves a detection precision of 92.4%， a recall rate of 93.6%， and a mean average precision （mAP） of 94.3%， outperforming both the original YOLOv8n and other popular detection models such as YOLOv5s and YOLOv3-tiny. These improvements provide a more accurate and reliable solution for fire detection， supporting advancements in fire prevention and control technology.
To further improve the prediction accuracy of tourist flow in scenic spots， a model based on the data preprocessing of variational mode decomposition （VMD） combined with multi-scale weighted permutation entropy （MWPE） was proposed， through the combination of double-layer convolution， bidirectional long short-term memory network and attention mechanism （DCNN-BiLSTM-Att）. Lushan Scenic spot in China was taken as an example to test the effectiveness of the method. The experimental results show that compared with traditional models such as DNN， LSTM， XGBoost， BiLSTM， DCNN-LSTM， and DCNN-BiLSTM， the DCNN-BiLSTM-Att model based on VMD-MWPE has better accuracy， robustness and generalization ability for tourist flow prediction in scenic spots.
To study the influence of Confucian culture on corporate charitable donation behavior，using the data of Shanghai and Shenzhen A-share listed companies from 2011 to 2023， the regional peer effect of corporate philanthropy and the influence of Confucian culture was empirically tested. The results show that： there is a peer effect on corporate philanthropy behavior of enterprises in the same region， and the corporate philanthropy behavior of enterprises in the same region has a significant positive impact on the corporate philanthropy decision of enterprises. The ideological connotation of Confucian culture about learning from others will strengthen the regional peer effect of corporate philanthropy and integrate it into corporate management decision-making through three aspects： enterprise environment， corporate culture and executive thought. By considering the research on the corporate philanthropy behavior of other corporations in the same region， this study more comprehensively analyzes the influence path of Confucian cultural influence on corporate philanthropy decision-making， providing theoretical support for strengthening regional cultural construction.
To address the problem that existing evaluations of scientific and technological innovation talents are often limited to a single dimension， a flexible competitive advantage evaluation method that could fully reflect the value of scientific and technological innovation talents under the constraint of organizational goals was proposed. First， based on the theory of competitive advantage， the opinions from the perspective that could best reflect the value of scientific and technological innovation talents were obtained. Second， the optimization model was constructed to obtain the consensus opinions of scientific and technological innovation talents. Furthermore， the deviation degree of the consensus opinion of scientific and technological innovation talents and the guidance opinion of organization was measured and compared with the threshold， so as to adopt different evaluation methods according to different deviation degrees. Finally， the effectiveness of the method was verified through the application of 10 scientific and technological innovation talents.
