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Marine science and technology talents are important resources and core elements for promoting the high-quality development of marine economy. This paper constructs a theoretical mechanism of marine science and technology talent agglomeration affecting the green total factor productivity of the marine economy, selects the data of 11 coastal provinces and cities in China from 2006 to 2019 for empirical testing, and further analyzes the mediating role of marine industrial structure upgrading and the moderating role of environmental regulation. The study finds that: there is a significant inverted U-shaped relationship between marine scientific and technological talent agglomeration and the green total factor productivity of the marine economy; there is regional heterogeneity in the impact of marine scientific and technological talent agglomeration on the green total factor productivity of the marine economy, with coastal areas south of the Yangtze River Basin showing a significant inverted U-shaped relationship, while the relationship is insignificant in coastal areas north of the Yangtze River Basin; the upgrading of marine industry structure plays a mediating role in the influence of marine scientific and technological talent agglomeration on the green total factor productivity of the marine economy, and the upgrading of marine industry structure can significantly promote the green total factor productivity of the marine economy; environmental regulation reinforces the inverted U-shaped impact of marine science and technology talent agglomeration on green total factor productivity in the marine economy. Based on this, policy recommendations are put forward to rationally guide the concentration of talents, focus on the matching of talents and industries, and optimize the environment for the development of talents.

In order to evaluate the autonomous combat effectiveness of ground-attack UAV efficiently, quickly and objectively, weighted mean of vectors algorithm (INFO) and K-fold cross-validation method are introduced to optimize the random forest algorithm (RF) to find the optimal parameter combination, and an autonomous combat effectiveness evaluation method based on optimized random forest is proposed. Firstly, based on the theory of weighted mean of vectors algorithm, the number and maximum depth of the random forest decision tree model are optimized. Secondly, combined with the ground-attack UAV combat tasks, the main operational factors of autonomous combat effectiveness evalua-tion are analyzed, the evaluation index system of autonomous combat effectiveness of ground-attack UAV is summarized, and the evaluation model of autonomous combat effectiveness of UAV based on INFO-RF is established. Finally, the evaluation model is verified by an example and compared with the traditional RF model, GA-RF model and SVM model. The results show that the output results of INFO-RF model have higher fitting degree and more accurate evaluation value. The results of the example effectively verify the rationality of the proposed method and the reliability of the optimization model.

Taking the application of artificial intelligence technology in the field of low altitude flight as an breakthrough point, this paper analyzes the challenges of unmanned platform, intelligent control and multi-task of low-altitude aircraft driven by artificial intelligence (AI) technology, which bring about multi-complex control objects, increasing control difficulty and expanding space-time depth. It puts forward the main decision-making methods and development approaches of improving the efficiency of flight examination and approval by pre-practice decision-making, real-time monitoring of flight status by autonomous decision-making, and accurate handling of violations by data-driven decision-making. This paper analyzes the main points, advantages and disadvantages of the application of artificial intelligence technology, soft killing technology and hard damage technology in the construction of management control and emergency treatment.

Green development and carbon neutrality in 2060 have become China's national development strategy. Land reclamation and ecological restoration in mining areas are the only way to green development of coal industry. It is found that in addition to restoring green and ecological functions, it also has a dual role in increasing carbon sinks, which not only prevents and suppresses carbon emissions due to land damage, but also increases carbon sinks due to vegetation and ecological restoration by analyzing the properties of land reclamation and ecological restoration in mining areas. Therefore, mining area ecological restoration is a green technology for increasing carbon sinks, which is in line with the national development strategy and will usher in new development opportunities. The incentive of the carbon neutral policy to the ecological restoration of the mining area is mainly embodied in seven aspects: guiding the scientific restoration, setting the leading standards, carrying out scientific and technological research, implementing the main responsibilities of enterprises, setting the project demonstration, strengthening financial support and establishing the market mechanism. Five major technical challenges will be faced by the ecological restoration of mining areas under the guidance of carbon neutrality: ① Carry out the research on the effect of reducing carbon and increasing sink of ecological restoration in mining areas from the four aspects of monitoring objectives, measurement parameters, parameter acquisition and calculation methods, and simultaneously carry out the assessment of reducing carbon and increasing sink of ecological restoration in mining areas; ② Leading role of the ecological restoration planning in the mining area in the increase of carbon sinks is played through the planning incorporating the concept of carbon neutrality, the planning measures and schemes for the increase of carbon sinks, and the optimization of restoration schemes based on carbon sink; ③ In addition to considering the function of water and soil conservation traditionally, increases the design and comparative analysis of increasing the carbon sink function in landform remodeling design; ④ Scientifically analyze and evaluate the sink increasing effect of different soil reconstructions, popularize sink increasing soil reconstruction technology, and simultaneously research the sink increasing reconstruction materials and soil profile; ⑤ Research and develop plant community selection and vegetation restoration technologies considering both ecological benefits and sink enhancement effects.

China possesses abundant pumice resources and thereby makes the utilization of pumice in the preparation of pumice aggregate concrete (PAC) a significant strategy for environmental protection and resource conservation. To obtain the effect of pumice pore structure variation on the compressive strength of PAC, PACs with strength classes LC20, LC30, and LC40 were prepared. Moreover, the pore structure of PAC was characterized using nuclear magnetic resonance to investigate the effect of pore structure variation on the compressive strength of PAC. Results showed that the higher the coarse aggregate content of PAC, the higher the percentage of large capillary and non-capillary pore sizes of PAC, corresponding to higher porosity and lower compressive strength. The hydration products in PAC continuously fill in the pore structure, the proportion of large capillary pores and non-capillary pore size gradually decreases, the proportion of small capillary pores and medium capillary pore size gradually increases, the pumice concrete matrix gradually becomes dense, and the compressive strength increases. The prediction model of the pore structure and compressive strength is established based on gray theory, and the relative error between predicted and tested values is not significant, which can effectively predict its compressive strength. It provides effective guidance for the engineering practical application of PAC.