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Abstract Optical observations play a crucial role in monitoring space debris, and long exposure large field-of-view telescopes exhibit robust detection capabilities for identifying space debris. Nevertheless, a substantial volume of data, intricate noise, nonlinearity, and target discontinuities significantly affect the observational process. To address these intricate celestial background conditions, an enhanced YOLOv8-based method for spatial debris detection is introduced into this study. Initially, a cross-scale feature fusion module is incorporated into the neck network, followed by a subtle processing step for the feature fusion component. Finally, the content-aware reassembly of features module is employed to replace the original upsampling module, which enhances the efficiency and accuracy of feature reconstruction, thereby achieving effective detection and identification of spatial debris targets. The study utilized a dataset comprising astronomical images captured by an open-source large-field-of-view optical telescope. The experimental results show that the detection accuracy and speed of the method are improved, and that they can meet the requirements of space debris detection in complex backgrounds.

Deep coal seams in China have the characteristics of low permeability, low porosity, and poor gas permeability, which makes the extraction of coalbed methane very difficult. To study the modification effect of acidic solutions on coal pore structure and mineral components, this study used three different concentrations (5%, 10%, and 15%) of organic acids (HCOOH and CH3COOH) to treat coal. Through industrial/elemental analysis, low-temperature nitrogen adsorption experiments, and x-ray fluorescence spectroscopy detection experiments, the pore size distribution, mineral elements, and oxides of the acidified coal were analyzed. The strength of the acid solution's modification effect on coal was analyzed, as well as the relationship between different mineral elements and changes in pore structure. The results show that the two acids have a pore expanding effect on coal, with an increase in average pore size; the pore size distribution is between 2 and 50 nm, belonging to mesopores; acetic acid has a stronger overall dissolution efficiency on inorganic minerals, while formic acid has a better effect on the removal of Ca and P elements, but none of them can effectively remove silicoaluminates; the content of Ca element in coal is positively correlated with the specific surface area provided by mesopores; and iron dolomite is not sensitive to the reaction with acetic acid, resulting in an opposite trend in Fe content and mesoporous specific surface area. Organic acid solution changes the pore and fracture distribution structure of coal through chemical dissolution by dissolving the mineral components inside the coal, thereby affecting its internal structural characteristics. [ABSTRACT FROM AUTHOR]