Chemical fertilizer is one of the most important input factors in agricultural production, but the excessive use of fertilizer inevitably leads to the loss of agricultural eco-efficiency (AEE). Therefore, it is necessary to explore the impact of fertilizer use intensity (FUI) on AEE. However, ordinary panel regression, based on the assumption of parameter homogeneity may yield biased estimation conclusions. In this regard, a panel quantile regression model (QRM) was constructed with the provincial panel data of China from 1978–2020 to test the difference and variation of this impact under heterogeneous conditions. The model was then combined with the spatial econometric model to explore the effect of the spatial lag factor. The results are as follows: (1) The QSM has unveiled a great improvement space for AEE that remains low overall, despite displaying a rising trend; the highest AEE is in the eastern region. (2) The FUI has a significant negative effect on AEE with the rise in quantiles, this negative effect tended towards weakening overall, although it rebounded slightly; it was stronger in areas with low AEE. It is necessary to consider the heterogeneous conditions in comparison with the average treatment effect of ordinary panel econometric regressions. (3) The impact of FUI shows significant variability in different economic sub-divisions and different sub-periods. (4) After considering the spatial effect of fertilizer use, the negative influence on local AEE had a faster decay rate as the quantile rose, but could produce a positive spatial spillover effect on AEE in neighboring areas. Local governments should dynamically adjust and optimize their fertilizer reduction and efficiency improvement policies according to the level and development stage of their AEE to establish a complete regional linked agroecological cooperation mechanism.

Wear failures of components often occur and cause great economic losses in modern industry production. To obtain excellent wear resistance surface will help reduce the abrasion. Herein, a wear-resistant iron-based alloy coating was deposited on a low-carbon steel substrate by argon arc overlaying, and sequentially surface nanocrystallized through ultrasonic impact treatment (UIT). Micro-structural, mechanical property (including nanohardness and elastic modulus) and wear behavior changes of the coating before and after UIT were experimentally investigated. In addition, the wear mechanism variation owing to the application of UIT was discussed. The results show that a highly deformed nanocrystalline layer with an average grain size in the range of ~100 nm was generated at a depth of approximately 34 μm from the treated coating surface, which contains a certain amount of the deformation-induced α’-martensite phase. Compared with the as-deposited coating, the coating after UIT processing exhibits considerable improvements in the ratio of nanohardness (H) to elastic modulus (E) and better wear resistance under the same wear test conditions. The wear mechanism has also changed from the adhesive type of the as-deposited coating to an abrasive type on the introduction of a nanocrystalline microstructure.

Wind power projects are a crucial step towards achieving the objectives of “carbon neutrality” and “carbon peak” because they can improve the energy crisis and contribute towards environmental pollution reduction. However, the risks of wind power projects cannot be ignored, and the success of the design phase can affect the risks and benefits of wind power projects throughout their life cycle. This paper first proposes causality hypotheses for four types of risk factors in wind power projects: policy, economy, technology, and construction. It constructs a structural equation model for wind power project risk factors and then tests and modifies the model. Then, based on the latent variables of policy, economy, technology, and construction, and the relevant explicit variables, the risk index evaluation system of the wind power project design phase is constructed. The risk assessment catastrophe model of wind power projects is further established, and it is used to evaluate the risk of the K wind power project in the design phase. The risk assessment can identify the overall risk and main risk sources in wind power projects in the design phase and provide countermeasures for effectively controlling risks in wind power projects in China.

This study aims to explore the effects of ultrasonic impact parameters on the surface modification of a stainless steel coating deposited on a medium-carbon low-alloy steel using argon arc surfacing welding. Ultrasonic impact treatment (UIT), at three different vibration strike numbers (40,000 times/(mm²), 57,600 times/(mm²), and 75,000 times/(mm²)) marked UIT–1, UIT–2, and UIT–3, respectively, was carried out to modify the surface structure and properties of the stainless steel coating. The surface morphological and structural features, phase compositions, grain size, topography, micro-mechanical properties, as well as the wear resistance of the coating before and after UIT with different impact parameters were experimentally investigated. The results of optical microscopy (OM), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and X-ray diffraction (XRD) analyses revealed that the grain refinement accompanied by the formation of the strain-induced α′–martensite occurred on the UIT-treated coating surface. With the increase in the vibration strike number, the surface grain size and roughness decreased, while the α′–martensite content increased. Micro-hardness after UIT was increased by about 19% (UIT–1), 39% (UIT–2), and 57% (UIT–3), and the corresponding wear rate obtained was decreased by 39%, 72%, and 85%, respectively. Significant improvements in wear resistance were achieved using UIT. However, an excessive vibration strike number on the per unit area (/mm²) might result in unwanted micro-cracks and delamination on the treated surface, deteriorating the performance of the coating. These findings validate that UIT parameters (such as the vibration strike number on per unit area) are of great importance to bringing about improvements in wear performance, and UIT is found to have a high potential in modifying the surface characteristics and optimizing the mechanical performances of the deposited coating for a wide range of potential applications.