In order to address the supply-demand imbalance in the increasingly complex and changing market environment, improving the accuracy of air cargo volume forecasting is of great significance for route planning and supply chain optimization. Firstly, based on monthly air cargo data from January 2000 to December 2022 as the training set, seasonal fluctuations and long-term trends were captured using seasonal and trend decomposition using loess (STL). Secondly, a deep learning time series prediction model (LSTM-SVR) was used to fit the nonlinear changes in cargo volume due to emergencies. Finally, the prediction model was tested based on monthly data for the entire year of 2023. The results indicate that the seasonal and combination prediction model (STL-SVR-LSTM) is more accurate in predicting air cargo volume during emergencies compared to traditional methods such as ARIMA, SVR, or LSTM. The data validation in 2023 shows that the root mean square error and average absolute percentage error of the seasonal and combination prediction models are 3.53 and 3.53%, respectively, with a goodness of fit score of 0.79. The LSTM model has the second best prediction results, with root mean square error and average absolute percentage error of 5.66 and 7.73%, respectively, and a goodness of fit score of 0.58, significantly better than the other two traditional models. It can be seen that this prediction model can adapt to the prediction of air cargo volume in complex environments, which is helpful in providing reference suggestions for enterprise operation and enhancing supply chain stability in case of emergencies.

In order to analyze the distortion effect of thin-walled box girder under lane load, the distribution law of stress amplification coefficient in thin-walled box girder was studied. The distortion angle and distortion generalized bending displacement were taken as node displacements. Based on the initial parameter solution of the homogeneous equation of the distortion control differential equation, the thin-walled box girder was divided into beam segment elements, and its element stiffness matrix and equivalent node load array were derived. Using Fortran language and referring to the calculation program FRAME2 for planar frame structures, a finite element program for beam segments that can be used to analyze the distortion effect of thin-walled box girders was obtained. The program was used to analyze the variation laws of the distortion internal forces and stress amplification factors of box girders under lane loads. The results show that the distortion warpage stress of three-span continuous box girder with variable cross-section under the action of lane load has a sudden change at the place of concentrated load, where the maximum and minimum values are obtained, the longitudinal distribution of stress amplification factor is similar to the longitudinal distribution of distortion warpage normal stress, both of which are symmetrically distributed along the span, the magnification factor of normal stress at the top and bottom of the section is 1.080 and 1.180 respectively. The points with smaller bending stress should not be considered when the magnification factor is taken into account.

The complex nonlinear characteristics and dynamic friction properties of the integrated brake-by-wire system were recognized as challenges for precise hydraulic pressure control. To address these issues, a precise hydraulic force control strategy was proposed for the integrated brake-by-wire system. Firstly, the structure and control framework of the integrated brake-by-wire system were analyzed, and equivalent simplified models were established for each component to facilitate controller design. Secondly, a three-layer cascade pressure control method was introduced for active braking in the integrated brake-by-wire system. Specifically, the pressure control layer was designed based on the active disturbance rejection control method, which mitigates the effects of hysteresis nonlinearity in the hydraulic system. The position control layer employs a robust sliding mode variable structure control method and addresses the dynamic and static friction issues in the transmission mechanism. The current control layer was designed using the linear matrix inequality method to enhance the braking motor's dynamic following performance. Joint simulation tests using AMESim-Simulink demonstrate that the integrated brake-by-wire system achieves good pressure control performance across various operating conditions, maintaining the steady-state pressure tracking error within 0.1 MPa, compared to the traditional proportion-integration(PI) control method, the mean transient pressure tracking error is reduced by 0.14 MPa using the proposed method, the mean steady-state pressure tracking error decreases by 0.8 MPa, and the response lag time is lowered by 0.04 s, which verifies the effectiveness of the control strategy proposed.

In order to explore the relationship between the ratio of non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol (NHHR) and the risk of rapid decline in kidney function, data from the China health and retirement longitudinal study (CHARLS) conducted in 2011 and 2015 was utilized. It includes 4 055 participants aged 40 and above with a baseline estimated glomerular filtration rate (eGFR) of at least 60 mL/(min·1.73m²), calculated using serum creatinine and cystatin C levels. Rapid kidney function decline is defined as a decrease in eGFR of 3 mL/(min·1.73m²·a). A multivariable logistic regression model was used to investigate the association between NHHR and the risk of rapid kidney function decline. Additionally, restricted cubic spline and threshold effect analyses were used to evaluate the dose-response relationship. The results show that over the 4-year follow-up, 447 participants (11.02%) experienced rapid decline in kidney function. In the fully adjusted multivariable logistic regression model, those in the highest NHHR group (T3) faced a 1.94-fold increased risk of rapid kidney function decline compared to the lowest NHHR group (T1) (OR=1.94,95%CI:1.46~2.61). As a continuous variable, each unit increase in NHHR is associated with a 1.21-fold increase in risk (OR=1.21, 95%CI:1.08~1.36). The restricted cubic spline analysis demonstrates a near logarithmic curve saturation effect between NHHR and rapid kidney function decline (P_nonlinearity<0.05). It is concluded that with NHHR ≤3.52, the risk increases as NHHR rises, while NHHR >3.52 marks a saturation point. In conclusion, among middle-aged and elderly individuals, a higher NHHR is linked to a greater risk of rapid decline in kidney function, displaying a nonlinear relationship.

In order to investigate the segregation characteristics of asphalt concrete with large size core walls, indoor and field tests were conducted. Firstly, the density ratio data of the indoor prepared asphalt concrete specimens were analyzed by extreme variance analysis. Secondly, the density data of the upper and lower parts of the asphalt concrete core samples with the maximum aggregate size of 37.5 mm drilled under different working conditions in the field were statistically analyzed based on the one-dimensional variance theory. Finally, the basic mechanical properties of the upper and lower parts of the asphalt concrete cores of the large-grain-size aggregate core wall were comparatively analyzed under different working conditions. The results show that the relatively large influence on the segregation of asphalt concrete in the heart wall is the largest aggregate size, followed by the test temperature, the smallest is the amount of asphalt, and the tendency of segregation of asphalt concrete in the heart wall increases with the increase of the aggregate size, the increase of asphalt dosage and the increase of the test temperature. The tendency of segregation of asphalt concrete with the largest aggregate size of 37.5 mm molded under different working conditions from large to small are: initial milling temperature of 145 ℃ with paving thickness of 30 cm, initial milling temperature of 130 ℃ with paving thickness of 30 cm, initial milling temperature of 145 ℃ with paving thickness of 40 cm and initial milling temperature of 130 ℃ with paving thickness of 40cm, respectively. The tendency of segregation of its own will be increased with the increase of the thickness, initial milling temperature and asphalt consumption, and with the increase of test temperature and asphalt consumption. The tendency of segregation will decrease with the increase of paving thickness and the decrease of initial milling temperature. The differences in Marshall stability, Marshall flow value and split tensile strength between the upper and lower parts of the core samples of asphalt concrete with the largest aggregate size of 37.5 mm molded under the above four working conditions are all within 6%, with good uniformity.

In view of the deficiency of the research on the prevention and control of bolt anchoring in engineering rock mass, the method of cooperative prevention and control analysis based on bolt pre-tightening force was put forward, and the cooperative prevention and control test of bolt, anchor agent and surrounding rock based on bolt pre-tightening force was carried out, the variation law of pre-tightening force of bolt was obtained and the cooperative prevention and control state of bolt anchoring was identified. The results indicate that improving the synergy between anchoring agents and the surrounding rock of anchoring holes, as well as between anchor rods and anchoring agents, is beneficial for their synergistic evolution and can effectively enhance the prevention and control effect. A method for determining the collaborative state of anchor rod anchoring is provided, which can comprehensively determine the collaborative state of anchor rod anchoring through the relaxation process curve and relaxation degree of anchor rod pre-tightening force. Increasing the contact surface between the anchor rod pad and the surrounding rock on the free face is beneficial for their synergistic evolution. Based on the application and monitoring of pre-tightening force, a method for determining the overall coordination degree of anchor rod anchoring prevention and control has been developed, and strategies for improving the coordination degree of each part of anchor rod anchoring have been proposed. During design, special attention should be paid to the coordination of each part of anchor rod anchoring to ensure that they can perform at their best and be in their optimal state. The research results have good guidance and reference significance for the anchoring mechanism, monitoring, prediction and prevention of prestressed anchor rods in engineering rock masses.

In China's shale gas exploration and development, skid-mounted equipment is typically used due to its ease of disassembly, transportation, and reassembly. This equipment is often operated in high-pressure and high-temperature environments. As a result, faults are more likely to occur. To prevent production accidents and eliminate safety hazards, regular monitoring and fault diagnosis of skid-mounted gathering and transportation equipment are essential. Only relatively independent and discrete fault information is typically provided by conventional fault diagnosis methods. The relationships between faults are not uncovered. In response, a two-stage association analysis technique was proposed to analyze fault data from shale gas gathering and transportation skid-mounted equipment. The relationships between faults and defect type distributions were identified, providing valuable guidance for equipment maintenance and process optimization. It has been demonstrated through experiments on real data that the method proposed accurately identifies the relationships between defect locations and the distribution of defect types in skid-mounted equipment. A new solution is provided for the preventive detection and optimized design of gathering and transportation skid-mounted systems.

An algorithm has been proposed to detect small targets in unmanned aerial vehicle(UAV) aerial images. The algorithm is based on an improved real-time detection Transformer (RT-DETR) and aims to address the challenges posed by complex backgrounds and a large number of small target samples. To enhance the feature fusion network, a dedicated feature fusion structure for small targets has been incorporated, utilizing rich location information from the shallow feature map to improve the network's ability to detect small targets. Furthermore, the last residual block in the BackBone has been removed to prevent an increase in additional parameters. Additionally, the MCP Block, a reconstructed BasicBlock structure in the backbone network, has been designed, which includes a multi-channel feature partial convolution module (MCPConv) to reduce redundancy in channel features and enhance the acquisition of multi-scale detail features. Moreover, a location encoding mechanism with learning ability has been introduced to obtain more accurate and expressive location information. The normalized weighted deviation(NWD) and mean precision-driven IoU(MPDIoU) positioning loss functions have been incorporated to accelerate the convergence speed of the model and reduce sensitivity to position deviation. Experimental results on the VisDrone2019-DET dataset demonstrate that the improved model reduces parameters by 62% compared to the original model, increases mAP50 by 3.9%, and improves FPS by 17%. The improved model exhibits superior detection performance compared to other mainstream detection models.

Soil seed banks serve as the foundation for plant restoration and succession, playing a crucial role in sustaining biodiversity and ecological balance. The effect of short-term enclosure and grazing ban on soil seed bank was studied in the marsh meadow of Napahai Lake in northwest Yunnan Plateau. Through field sampling and seed germination identification, the effects of grazing and short-term confinement (3 years) on species composition, diversity and functional group structure of topsoil seed bank were compared. The findings show that short-term grazing exclusion significantly alters the diversity of the soil seed bank, reducing the Shannon-Wiener and Pielou indices (P<0.05) and increasing the density of sedge seeds (P<0.05). Weeds dominate in both enclosed and grazed conditions, with grasses and sedges following, and legumes being minimal. The percentage of weed species decreases, while that of sedge species increases under grazing exclusion, with no significant change observed in grasses and legumes. Weed importance values are significantly negatively correlated with grass and sedge importance values (P<0.05), and grass density is significantly positively correlated with sedge density (P<0.05). These results indicate that while short-term grazing exclusion reduces the diversity of the soil seed bank in swamp meadows, it also enhances the replenishment and recovery of sedge seeds, offering new insights for the restoration management of wetland ecosystems.

To address the current situation of low flatness, poor cutting quality and cane bud damage at the cane cutter due to insufficient optimization of the structure and motion parameters and installation coordination of the cutting tool of the cane seed cutter. Finite element cutting simulation tests were conducted using single-factor tests on the distance between the cutting edge and the pivot point of the transport roller, tool drop speed, tool installation offset angle, tool front angle and tool back angle of the cane seed cutter to determine the evaluation indexes affecting the cane seed cutting quality and the trend of the influence of each factor on this index. The significant interaction effect of each factor on the evaluation index was analyzed based on the rotating orthogonal test, and the quadratic polynomial regression model of the orthogonal test results was obtained. Combining the agronomic requirements with the cutting characteristics of the tool, the optimal evaluation index was established, the optimized optimal combination of parameters was obtained, and the cutting section simulation test and bench validation test were conducted. The final selection results are as follows: the distance between the incision and the fulcrum is 177.944 mm, the tool landing speed is 1.569 m/s, the tool installation offset angle is 5.923°, the tool front angle is 10.899°, and the tool back angle is 8.637°. The equivalent stress at the incision site and the sugarcane shoot site are 5.053 mm and 1.592 MPa, respectively. The comprehensive analysis error rate is 4.97%. This study can provide a research basis for the optimization of the structure parameters and installation parameters of sugarcane seed cutting knife and its motion parameters, so as to improve the seed cutting quality of cane.