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In order to reveal the destructive mechanism of loess landslide induced by stagnant water on the combined surface, and to clarify the influence of the main control factors, this paper takes a typical loess landslide in northern Shaanxi as the research object, analyzes the structure of the rock and soil body, and the excavation and filling construction through the geohazard survey, and analyzes the process of traction sliding caused by the stagnant water on the combined surface at the different stages of the project by combining with the calculation of the stability of the slope body. Further the article analyses the process of traction sliding caused by water on the combined area due to construction by means of a discrete element model, and delves into the mechanism of strength reduction of saturated loess. The results show that: 1) the combined surface stagnant water type loess landslide has the characteristics of sudden sliding and rapid evolution, which is highly hazardous and difficult to prevent and control; 2) the slope destabilization is controlled by the engineering geological conditions, and the slope excavation changes the original mechanical equilibrium conditions of the slope, which provides the dynamic conditions for the traction sliding of the slope; 3) the change of the hydrogeological environment results in the obstruction of the natural drainage channel, which leads to the formation of continuous sliding surface due to stagnant water on the combined surface, and the formation of a continuous sliding surface due to stagnant water on the combined surface. Surface stagnant water to form a continuous slippery surface, inducing the overall destabilization of the slope damage; 4) loess strength index with the increase of saturation and the exponential function form of reduction, and when the saturation degree reaches more than 80%, the strength index of the soil body to reach the basic stability. The article expanding the ideas of landslide control and analysis, and the research results will provide a theoretical basis for the design of junction landslide management in the loess areas of northern Shaanxi. [ABSTRACT FROM AUTHOR]

Geological mapping involves the identification of elements such as rocks, soils, and surface water, which are fundamental tasks in Geological Environment Remote Sensing (GERS) interpretation. High-precision intelligent interpretation technology can not only reduce labor requirements and significantly improve the efficiency of geological mapping but also assist geological disaster prevention assessment and resource exploration. However, the high interclass similarity, high intraclass variability, gradational boundaries, and complex distributional characteristics of GERS elements coupled with the difficulty of manual labeling and the interference of imaging noise, all limit the accuracy of DL-based methods in wide-area GERS interpretation. We propose a Transformer-based multi-stage and multi-scale fusion network, RSWFormer (Rock–Soil–Water Network with Transformer), for geological mapping of spatially large areas. RSWFormer first uses a Multi-stage Geosemantic Hierarchical Sampling (MGHS) module to extract geological information and high-dimensional features at different scales from local to global, and then uses a Multi-scale Geological Context Enhancement (MGCE) module to fuse geological semantic information at different scales to enhance the understanding of contextual semantics. The cascade of the two modules is designed to enhance the interpretation and performance of GERS elements in geologically complex areas. The high mountainous and hilly areas located in western China were selected as the research area. A multi-source geological remote sensing dataset containing diverse GERS feature categories and complex lithological characteristics, Multi-GL9, is constructed to fill the significant gaps in the datasets required for extensive GERS. Using overall accuracy as the evaluation index, RSWFormer achieves 92.15% and 80.23% on the Gaofen-2 and Landsat-8 datasets, respectively, surpassing existing methods. Experiments show that RSWFormer has excellent performance and wide applicability in geological mapping tasks. [ABSTRACT FROM AUTHOR]

A K2CO3 promoted spirocyclopropanation of thiazole‐derived oxadienes with bromomalonate via 1, 4‐addition‐induced dearomatization strategy has been developed. The pathway features a broad substrate scope, operational simplicity and high degree of synthetic efficiency to afford series of functionalized spiro‐cyclopropanation frameworks in 88 %–96 % yields, which enriches the research contents of thiazole‐derived oxadienes involved reactions. All products obtained herein contain two contiguous quaternary centers and their further synthetic applications are also demonstrated. [ABSTRACT FROM AUTHOR]

Base promoted [4+3] annulation of trifluoromethylpyrazole(TFPZ) derived α,β‐unsaturated ketones with crotonate‐derived sulfur ylides provided a diverse set of CF3‐containing oxepino[2,3‐c]pyrazole motif in good to excellent yields through a simple, mild and fast manner. Significantly, one‐pot strategy could be successfully applied to this transformation from available materials. Also, the utility of our versatile protocol was further demonstrated by gram‐scale reaction and useful derivation. [ABSTRACT FROM AUTHOR]

Stated preference analyses seeking to determine the public's value for air quality improvements often estimate willingness to pay (WTP) for days at a specified minimum quality threshold (e.g., days with clean air), but do not consider the temporal distribution of pollution levels below this threshold. This paper develops a choice experiment designed to evaluate WTP for a more complete distribution of air quality improvements, including the number of days per year at multiple air quality levels. The model is applied to a case study of air quality improvement in the core districts of Xi'an City, China. Results from a linearly constrained mixed logit model demonstrate that average household WTP for improving a lightly polluted, moderately polluted, heavily polluted, or severely polluted day to a clean air day is 7.42, 8.90, 13.06, and 24.28 RMB per year, respectively. These results show that WTP depends not only on the total number of clean air days, but on the total distribution of pollution levels across all days of the year. Results are directly relevant to the development of clean air policies in China, for which benefit estimates are currently unavailable. [ABSTRACT FROM AUTHOR]