Crop straw chopping and returning technology has gained global implementation to enhance soil structure and fertility, facilitating increased crop yield. Nevertheless, technological adoption faces challenges from inherent limitations in machinery performance, including poor chopping and returning quality and high energy consumption. Consequently, this review first presented a theoretical framework that described the mechanical properties of straw, its fracture dynamics, interactions with airflow, and motion characteristics during the chopping process. Then, based on the straw returning process, the chopping devices were classified into five types: the chopped blade, the chopping machine, the chopping device combined with a no-tillage or reduced-tillage seeder, the chopping and ditch-burying machine, the chopping and mixing machine, and the harvester-powered chopping device. Advancements in spreading devices were also summarized. Finally, six key directions for future research were proposed: developing an intelligent field straw distribution mapping system, engineering adaptive self-regulating mechanisms for chopping and returning equipment, elucidating the mechanics and kinematics of straw in the chopping and returning process, implementing real-time quality assessment systems for straw returning operations, pioneering high forward-speed (>8 km/h) straw returning machines, and establishing context-specific straw residue management frameworks. This review provided a reference and offered support for the global application of straw returning technology.

A novel external buoy type wave energy device with hydraulic conversion system used for navigation lighted buoys, named floating external double buoys wave energy device, is put forward and investigated by numerical calculations and model experiments. The hydrodynamic performance of the device under regular waves is numerically calculated based on linear potential flow theory and boundary element method. The generalized modal method is used to solve the hydrodynamic problems of multi‐buoy with hinged constraints. The model experiments are carried out in a 2D wave tank with a depth of 0.9 m. The wave height is set to 1/40 of the wavelength. The influence of wave period and damping loads on the hydrodynamic performance of the device is tested. The results of numerical calculations and model experiments have shown that the appropriate selection of hydraulic damping coefficient is of great significance to improve the capture width ratio of the device, and this device has good capture performance in a certain wave range, and it is expected to effectively solve the problem of continuous power supply for middle and small types of navigation lighted buoys.

The aim of this study was to investigate the influence of operational and design parameters on the conveying efficiency and material layer stability of air slides and to optimize the parameters of the XZ200 air slide. A gas–solid coupled simulation of the conveying process was conducted using ANSYS v2023 and Rocky v23R1 software. Three key variables—inclination angle, input air velocity, and permeable layer porosity—were analyzed to evaluate their effects on wheat flour conveying efficiency and layer stability. Orthogonal experiments and matrix analysis were applied to comprehensively assess the numerical simulation results. The findings reveal that the conveying ratio is positively correlated with input air velocity and inclination angle but negatively correlated with permeable layer porosity. Meanwhile, material layer fluctuation and stability increase with inclination angle but decrease with higher porosity. Through orthogonal testing and matrix analysis, the optimal parameter combination was determined as follows: input air velocity of 1.8 m/s, porosity of 37.84%, inclination angle of 6°, conveying ratio of 96.52%, and material layer fluctuation of 4.39 mm. This study provides a reference methodology for gas–solid coupled simulation in air slide design and offers practical guidance for parameter optimization in air slide systems.