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AbstractThis article analyzes the impact of digital economy development on enterprise investment by using the “Broadband China” strategy as an exogenous shock and applying a multi-period difference-in-differences (DID) model to panel data from 2010 to 2020. The results indicate that the digital economy significantly promotes enterprise investment by improving R&D, obtaining more financing from banks, and enhancing internal control. Furthermore, the impact of the digital economy on enterprise investment varies significantly among enterprises that have a high R&D expenditure, are state-owned, large-scale, lower financially constrained, or capital-intensive. The conclusion is supported by a series of robustness tests. This study clarifies the role and influence of government-led digital economy infrastructure construction on micro-enterprise investment decisions and provides recommendations for boosting the development of the digital economy and China’s enterprise investment development. [ABSTRACT FROM AUTHOR]

The penetration force and depth of the slip teeth are important factors influencing the hanging capacity of liner hanger, which can lead to failure of well cementation. In this study, a method to calculate the penetration force of dual-wedge slip teeth was presented by considering the surface configuration and the force transfer mechanism of dual-wedge slip in three dimensions. The interaction between dual-wedge slips and casing was simulated using ABAQUS 6.14 software, and the contact force (penetration force) was obtained. Experimental research was carried out to verify the correction of calculation and simulation. The strain of casing was obtained after the dual-wedge slips set under axial loads. The experimental results, theoretical prediction, and the numerical simulation are in good agreement. The effects of geometrical parameters on force transfer characteristics were discussed, which shows that the penetration force of dual-wedge slips increases with increase in the liner weight and Eulerian angle γ, and it decreases with the increase in Eulerian angle α and friction coefficient. The geometric parameters of the dual-wedge slip can be designed to obtain an optimal penetration force, and ensure that the slip teeth penetrate into the inner wall of casing without damage to the casing. The penetration force can be obtained by optimizing the parameters related to geometry of dual-wedge slips. [ABSTRACT FROM AUTHOR]

This paper analyzes the impact of urbanization on environmental pollution by using provincial and municipal panel data from 2004 to 2015 in China. Using the spatial Durbin model, the study finds a notable difference between the impact of urbanization on residential and industrial wastewater and waste gas. Urbanization in China will significantly improve the emissions of residential wastewater and industrial waste gas in local and neighboring provinces. The effective improvement of energy use, or energy efficiency, plays a key role in reducing environmental pollution and can effectively curb the emission of pollutants. [ABSTRACT FROM AUTHOR]