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Acidic mine drainage (AMD) is one of the primary pollutants from abandoned mines. This type of pollution is characterized by its extensive area, prolonged duration, and challenging detection process, especially in karst region with intricate hydrological systems, thereby posing a significant threat to the sustainable development of the economy. This paper focuses on the pollution of acidic mine water in the karst region of Southwest China and adopts a comprehensive watershed pollution management strategy. Considering the unique hydrogeological structure of the karst mines, the active water cycle, and the sensitivity and fragility of the ecological environment, this study proposes a set of acid mine drainage pollution control methods based on hydrogeological structures. These include “zonal management, one policy per mine; source control, pollution reduction; and end-of-pipe treatment, standard discharge.” This study applies coal mine water prevention and control techniques to environmental management, developing a series of source control methods including “filling, isolating, blocking, intercepting, draining, and controlling”. It also integrates physical, chemical, and biological methods for the end-of-pipe treatment of acidic mine water. This approach has been successfully applied to the management of acidic mine drainage in the Yudong River basin in Kaili, Guizhou. Long-term monitoring of the ''three-fields and four-water” revealed that rainfall significantly influences mine water quality. The study identified a “U-tube effect” whereby mine water exacerbates the pollution of karst water, leading to the development of a comprehensive prevention and control strategy termed the “three blocking (obstruction) and one guarantee” project. A comparative analysis of total iron content in the basin before and after treatment demonstrated a marked reduction, from 97.8mg/L to less than 0.3mg/L. This study provides a typical example for the prevention, control, and management of acid water pollution in karst areas across the watershed, and can serve as a reference for similar pollution management efforts.

Intrinsically stretchable organic photovoltaic cells (OPVs) have garnered significant attention as crucial devices for powering next‐generation wearable electronics. Despite the rapid power conversion efficiency gains in champion OPVs, their brittle stretchability has failed to meet the demands of the Internet of Things era, severely hindering further development and practical applications. In this regard, a new dual‐donor polymer blending strategy is demonstrated for constructing intrinsically stretchable OPVs by designing a novel high‐molecular–weight conjugated polymer PM6‐HD. This PM6 derivative featuring long alkyl chains can reach a sufficiently high molecular weight and thus exhibits a high fracture strain exceeding 90%, which is ≈12 times higher than the benchmark PM6. Synergistic optimization of mechanical properties and photovoltaic performance in polymer:small molecule and all‐polymer systems constructed from the physical blends of PM6 and PM6‐HD is achieved. Crucially, the resulting intrinsically stretchable OPV demonstrates excellent stretchability and stability, with a record PCE80% strain of 50.3% and the efficiency retention of above 80% even after 1000 cycles of cyclic stretching at high strains. This work contributes to the advancement of intrinsically stretchable OPV technology and opens up new possibilities for its integration into wearable electronic devices. [ABSTRACT FROM AUTHOR]

[Objectives] In order to solve the problem of the longitudinal vibration of submarine propulsion shafting,[Methods] complex submarine propulsion shafting is simplified to a uniform stepped shaft continuum model, Wave Propagation Analysis (WPA) is used and the longitudinal vibration transfer relationship of each axis is deduced. Combined with the actual propulsion shafting boundary conditions, the steady state response of propeller shaft longitudinal vibration under propeller excitation is obtained.[Results] The reliability of the model is verified by comparing the theoretical calculated value with the finite element software simulation results and experimental test data, proving that it can be used for the longitudinal vibration analysis of propulsion shafting. Dimensionless formulas for the first natural frequency of the longitudinal vibration of submarine propulsion shafting are deduced, providing convenience for further analysis.[Conclusions] The results have definite value for engineering applications.

The defect arising from the thermal coefficient mismatch of different phases was an important factor of reducing strength in eutectic composite ceramic. Based on the equivalent inclusion method and the interaction direct derivative（ IDD）estimate,stress intensity factor of annular defect under residual stress field and applied loading was calculated,and annular defect stability was analyzed. And the influence of particle stiffness,shape and volume fraction was investigated. Results indicated that,the crack nucleation was most easily produced in the oblate particle; stiff particles caused average applied stress reduced in matrix,and it reduced greater when the stiff particle was prolate elliptic,while the soft particle had the contrary effect. Stress intensity factor of defect was controlled by residual stress as the defect extension was small while it was controlled by applied stress for large defect extension. Prolate elliptic particle was beneficial to improve strength.