Two schemes, hollow shaft and solid shaft were proposed for the cantilever high-speed rotor of a turbofan engine during the structural design stage. Based on the beam element finite element method, rotor dynamic analysis models with hollow shaft and solid shaft were established, and critical speed and vibration mode calculations were carried out. The calculation results show that hollow shaft structure is suitable for the rotor. Then, an analysis was conducted on the sensitivity of the unbalance response of a rotor with a hollow shaft to the unbalance amount at the characteristic position, providing a basis for the selection of balance surfaces in high-speed dynamic balance test. Finally, the dynamic characteristics test of the simulated rotor with hollow shaft within the full speed range and the high-speed dynamic balance test research at the working speed were completed. The rotor smoothly crossed the two orders bending critical speed and safely operated to the working speed, verifying the rationality of the rotor’s hollow shaft structure and dynamic design. Compared with the experimental results, the calculation error of the established finite element model is not more than 4.08%, which well reflects the dynamic characteristics of the rotor. After high-speed dynamic balancing, the deflection of the rotor at the working speed is significantly reduced, not less than 33.33%. The research results provide reference and technical support for the structural, dynamic design, and experimental research of real low-pressure rotors, and has important engineering value.

In order to alleviate the collision risk of non-intersecting runways simultaneous operation, it is necessary to apply a control strategy conforming to the operation characteristics. A collision risk assessment model was constructed by using event tree analysis and Monte Carlo method. Based on event tree analysis, the event to be solved was determined. The probability of related events was calculated by Monte Carlo method. By statistical and fitting the collision event data obtained by the experiment, the safety target level was standardized and the control strategy was put forward. Finally, taking the approach of 01L and the departure of 29R on the non-intersection runways of Daxing Airport as an example, the departure shielding window (0.41~7.39 km) was obtained. Using this strategy, the risk of aircraft collision can be controlled at an acceptable level. The proposed computational model of departure shielding window is of general applicability to the formulation of safe operation control strategies for non-intersecting converging runways.

Due to the limitations of traditional ice force measurement methods in terms of stability and reliability, and the high sensitivity and anti-interference capabilities of fiber optic sensing technology was given, a fiber optic ice force sensor was developed. The effectiveness of this sensor was evaluated in the context of its application in marine structures. Based on the fundamental principles of fiber optic sensing technology and the design requirements of the ice force sensor, the research, design, and installation processes of the sensor were described in detail, including the design calculations of the elastic element, the selection and arrangement of the fiber optic sensors, and the construction of the data acquisition system to ensure that the precision requirements for ice force measurement were met. A winter field measurement of ice force was conducted at an observation station in the northern Bohai Sea. Field ice force data were successfully collected and analyzed, and the actual monitoring performance of the sensor was evaluated. The experimental results indicate that the system exhibits good stability and reliability in practical applications. The developed fiber optic ice force sensor provides a new reliable technical means for ice force measurement in marine engineering and lays a foundation for further research in structural health monitoring.

Due to the unclear constitutive relationship between the structure and performance of styrene-butadiene-styrene block copolymer(SBS) modified asphalt, the current way to improve the performance of SBS modified asphalt is still to simply increase its SBS content. However, early pavement diseases are still frequent. To explore the effect of swelling degree of SBS on the rheological properties of modified asphalt and its internal mechanism without increasing SBS content. The microstructure of SBS modified asphalt was observed by fluorescence microscope. The conventional properties and rheological properties of SBS modified asphalt were analyzed by dynamic shear rheometer. The internal mechanism of the influence of SBS swelling degree on the performance of SBS modified asphalt was revealed by molecular dynamics. The results show that the fully swollen star-line blended SBS modified asphalt has a higher swelling area, and has obvious performance advantages in terms of conventional performance, rheological properties and anti-aging properties. Molecular simulation shows that the complete swelling of SBS makes the radial distribution function peak of SBS modified asphalt higher, which improves the interaction between SBS molecules and light components in SBS modified asphalt. On the basis of maintaining the original stable asphalt colloid structure, SBS styrene ends are interconnected to form π-π conjugate, which improves the toughness of SBS network.

In order to solve the problems of missed detection and false detection in the current remote sensing image small target detection task, a SMCA+CSC+shape-aware intersection over union loss(SIoU)-you only look once(SCS-YOLO) remote sensing image small target detection algorithm was proposed. Firstly, in response to the problem of small and clustered targets in remote sensing images, a spatial multi-scale convolutional attention module(SMCA) was constructed to improve the model’s feature extraction ability of spatial and channel information. Secondly, in order to solve the problem that the semantic information of small targets was easy to be lost during deep network transmission, the aggregation subpixel convolution module concentrated sub-pixel convolution(CSC) was designed, and the multi-scale aggregation feature extraction method was used to enhance the ability of the network to extract semantic information. Finally, the SIoU loss function was used to replace the complete intersection over union loss(CIoU) loss function in the original model, which accelerated the convergence speed of the network. The average of the average precision(mAP)of the SCS-YOLO model reaches 97% and 90.9% on the RSOD and NWPU VHR-10 datasets, respectively, which is 2.2% and 2.7% higher than that of the original model, which shows the effectiveness of the method in the small target detection task of remote sensing images.

Serving as a clean and renewable energy source, wind energy plays a significant role in mitigating the increasingly severe energy crisis. However, the fluctuation and randomness of wind speed pose severe challenges to the stable operation of power systems. To address this issue, a combined short-term wind speed forecasting model named CEEMDAN-RIME-CNN-BiLSTM-AM was proposed, which was based on complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN), rime optimization algorithm (RIME), convolutional neural network (CNN), bidirectional long short-term memory network (BiLSTM), and attention mechanism (AM). Initially, the CEEMDAN algorithm was applied to the original wind speed series to obtain a series of relatively stable sub-modes, thereby reducing the volatility of the wind speed series. Subsequently, the CNN hyperparameters were optimized using the RIME algorithm to establish the CNN-RIME model for adaptive extraction and mining of wind speed data. Then, the BiLSTM-AM model was employed to forecast the processed data. Finally, the forecasting results of each sub-series were superimposed to obtain the final forecasting result. A comparative experiment was conducted using an actual wind speed dataset from a certain location. The proposed model demonstrates good forecasting performance in both single-step and multi-step forecasting, providing a reference for scheduling plans to maximize energy utilization and power supply.

A numerical simulation of groundwater dynamics in the Sugan Lake Basin was conducted by using MODFLOW, and 50-year predictions were made for four different water diversion schemes. The results from MODFLOW simulations fit well with the measured data, indicating that the established model can be used for predicting the groundwater dynamics in the Sugan Lake Basin. The MODFLOW simulation results under different water diversion schemes reveal that over a period of 50 years, as the amount of diverted water increases, the shrinkage rate of the large Sugan Lake’s area also increases, and the groundwater level in the Sugan Lake Basin shows a general declining trend. The impact of inter-basin water transfer exhibits certain time lags and spatial heterogeneity. Considering both the water diversion requirements and the effects of the water diversion project on the ecological environment of the Sugan Lake Basin, it is suggested that a water diversion scheme of 1.0×10⁸ m³/a is more appropriate. The research results provide important scientific theoretical support for assessing the impacts of inter-basin water transfer projects on the ecological environment of the Sugan Lake Basin and for determining suitable water diversion schemes.

The velocity measurement of trunk canals and rivers is regarded as an important basis for water resources management and flood prediction. The techniques and methods for trunk canals velocity measurement based on machine vision were analyzed and synthesized. Particular focus was placed on reviewing the principles, technologies, and recent developments of particle image velocimetry, particle tracking velocimetry, space-time image velocimetry, optical flow methods, and deep learning-based flow measurement methods in recent years. Finally, the existing challenges and issues were addressed, and potential future development directions were proposed.

Groundwater plays a pivotal role in the production and sustenance of life. However, the potential geologic risks associated with its exploitation must be acknowledged. Changes in groundwater levels have been shown to precipitate geologic disasters such as landslides, mudslides, and ground subsidence. Therefore, the mastery of groundwater information is of great scientific significance for disaster prevention, mitigation, and the rational use of water resources. The temperature tracing method is recognized as a promising technique with significant applications in preventing and providing early warning of geological hazards, such as landslides and mudslides. Among the many methods available, this technique was noted for its great potential. The recent groundwater exploration methods, theoretical research, and new indoor experimental research methods was focused on. The latest research progress related to the groundwater method of geothermal inversion in the seepage of rivers and dams, landslides, and groundwater exploration was reviewed. Through comparative analysis with the traditional electric method of exploration, current theoretical models and new problems faced by the practice of engineering exploration were analyzed. Future research should focus on multi-field coupling, multi-parameter integration, analysis of groundwater patterns in special soil sites, dynamic monitoring of groundwater for major projects, and early warning and prediction of geological disasters will be focused on. These research directions will provide essential scientific and technical support for the prevention of geological disasters and water resources management.

Squeeze film damper (SFD) is a commonly used vibration reduction device in rotating machinery such as aero-engine. With the development of aviation science and technology, many new structures of SFD have been derived and developed. The categories of new structural squeeze film dampers from the aspects of structural characteristics, vibration reduction characteristics, vibration reduction effects, and application situations were summarized. Besides, the current research status of new structural squeeze film dampers in China in recent years were also summarized. The shortcomings of current research on new structural squeeze film dampers were pointed out, and an outlook of proposes directions and prospects for future research on new structural squeeze film dampers was made. Besides,the application prospects of new structural squeeze film dampers were pointed out. The results provides a reference for the application and selection of new squeeze film dampers in the vibration reduction design of rotor systems in rotating machinery such as aero engines.