The project management of high-voltage substation expansion project is facing greater construction safety risks. It is of great significance to ensure the safety of personnel and the reliable operation of power grid to do a good job in the safety risk management of high-voltage substation expansion project construction. The aim of this study is to establish a dynamic control system for safety risk system dynamics (SD) of high voltage substation expansion construction based on the combination of analytic hierarchy process and fuzzy comprehensive evaluation (AHP-FCE). Firstly, the weights and scores of risk indicators are determined based on AHP-FCE theory to carry out static risk assessment. Then, based on SD, a dynamic evaluation model is established to analyze the change trend of risk indicators over time and the most sensitive secondary risk indicators among the primary risk indicators through causality diagram and stock flow diagram. Finally, this study proposes three control strategies, and simulates the implementation effect through SD, which provides an effective reference for project managers to dynamically control the safety risks of high-voltage substation expansion construction.
A nonlinear shaft-plate coupled load transfer model is proposed for axially compressed helical piles. The novelty of the model lies in treating the helix plate as a discrete internal bearing interface embedded within a continuous shaft load transfer system, so that the axial-force jump, displacement compatibility, and nonlinear resistance mobilization are solved simultaneously within a single boundary value problem. Hyperbolic load–displacement relations are adopted for both the distributed shaft resistance and the localized plate bearing, with the initial stiffness parameters ks0 and Kb0 derived from the same elastic continuum solution to ensure internal consistency within a unified framework. Displacement compatibility and axial force jump at each plate location complete the nonlinear boundary value problem, which is solved through an iterative finite-difference scheme updating equivalent secant stiffness until convergence on both plate load and displacement field. The pile head response, axial force distribution, shaft friction mobilization, plate bearing ratio, and interface stiffness degradation are obtained. Parametric studies reveal that pile geometry, helix embedment depth, and soil stiffness gradient collectively govern the nonlinear load transfer characteristics. Within the investigated parameter range, increasing load promotes a progressive redistribution of axial resistance from the shaft toward the helix plate. The extent of this transition depends on the relative shaft-plate strength and stiffness, rather than being a fixed response mode. Both shaft friction mobilization and interface stiffness degradation exhibit a spatially non-monotonic distribution, peaking in a primary transfer zone above the helix plate and diminishing below. This depth-zoning pattern is induced by plate-mediated load diversion and is absent in conventional straight piles.
Grounded in the entity-referent correspondence (ERC) framework, this study examines how three authenticity dimensions of AI-generated destination portrayals, true-to-ideal, true-to-fact, and true-to-self, relate to destination attractiveness via parallel and sequential pathways of place imagination and mental simulation. Analysis of 406 participants exposed to an AI-generated tourism video reveals that true-to-ideal and true-to-fact authenticity show significant direct effects on destination attractiveness, whereas true-to-self authenticity operates entirely indirectly, consistent with a meaning-making route. For parallel mediation, true-to-ideal and true-to-self authenticity exert significant indirect effects via both mediators, whereas true-to-fact authenticity does so only through place imagination. The sequential pathway from place imagination to mental simulation receives consistent support across all dimensions. Theoretically, this study advances the ERC framework from a static typology to a processual account by delineating the distinct cognitive routes of each referent and highlighting both the conceptual promise and measurement challenges of operationalizing true-to-self authenticity as perceived communicative sincerity in algorithmically generated portrayals.
Controlling CO emissions from the steel industry is crucial for continuously improving air quality. A critical challenge is the catalytic removal of CO from flue gases, which is often severely hindered due to the presence of SO2. Surface electronic engineering offers a feasible approach for alleviating sulfur poisoning in CO oxidation of conventional Pt/TiO2 catalysts. Herein, we synthesized reduced Pt/TiO2 (Pt/TiO2-R) that exhibited enhanced CO oxidation activity, achieving similar to 100% conversion at 190 degrees C, and superior sulfur resistance, maintaining activity after 12 h exposure to 200 ppm SO2 at 220 degrees C. The CO adsorption characterization and density functional theory (DFT) calculations demonstrated that Pt/TiO2-R exhibited a strong chemical adsorption for CO (E-ads = -3.99 eV) and a weak adsorption capacity for SO2 (E-ads = -1.81 eV). The strong electron transfer from Pt to TiO2 substrates upshifted the Pt d-band center in Pt/TiO2-R, which rendered the surface Pt high electron-donating and thereby favoring CO adsorption over SO2 at the active sites. Charge density difference analysis shared a similar direction of the electron transfer from the Pt to CO. The larger electrons transferred from Pt/TiO2-R to CO (0.23 |e|) compared with Pt/TiO2-O to CO (0.01 |e|), indicating the higher reactivity in Pt/TiO2-R. This work focuses on preferentially promoting CO adsorption over SO2, which provides a sustainable pathway for CO abatement in steel industry emissions.
Comprehensive Summary Since its discovery in 1997, the Catellani reaction, enabled by palladium/norbornene (Pd/NBE) cooperative catalysis, has matured into a powerful strategy in organic synthesis for the iterative ortho- and ipso-difunctionalization of aryl halides. This methodology is fundamentally dependent on the formation of key aryl-norbornyl-palladacycle intermediates, which facilitate the one-step assembly of multiple C-C bonds. Recently, the emergence of Pd/NBE catalysis has broadened the applicability of this platform, allowing for efficient and stereocontrolled construction of chiral compounds. In this review, we comprehensively summarize recent advances in Pd/NBE cooperative catalysis for the synthesis of diverse chiral compounds, with a focus on four dominant strategies: chiral substrate control (exploiting inherent substrate chirality), chiral ligand control (introducing chirality during the termination step), organocatalytic control (via enamine intermediates generated from chiral amines), and chiral norbornene control (wherein the norbornene conveys stereochemistry through sequential stages, including C-H activation, kinetic resolution, axial chirality induction and desymmetrization). These developments have enabled highly asymmetric transformations of aryl iodides, triflates, and boronates, granting efficient access to diverse, complex chiral compounds including C-aryl glycosides, carbon- and phosphorus-stereogenic centers, varied axial chiral motifs, planar chiral ferrocenes, and inherently chiral aromatics. Collectively, these accomplishments underscore the considerable potential of this catalytic platform for constructing core scaffolds in bioactive molecules and functional materials. Despite these advances, key challenges persist. The structural diversity of directly accessible chiral compounds remains narrow; stereocenters bearing heteroatoms (e.g., sulfur, boron, or silicon), C-B axial chirality, and planar or helical chiral macrocycles remain particularly underexplored. Furthermore, the functionalization of sterically hindered substrates, especially those governed by the "meta-constraint", remains a significant challenge, and the scope of compatible electrophiles and terminating reagents requires significant broadening. Looking ahead, integrating this asymmetric catalytic strategy with emerging techniques such as photocatalysis and electrosynthesis offers a promising avenue to overcome current mechanistic and selectivity limitations, thereby opening new frontiers for the design of chiral compounds with novel scaffolds and unique functionalities.
