In order to further explore the simulation of nanofluid heat pipe, the VOF(volume of fluid) model in Fluent software was used to take single nanofluid (TiO₂-H₂O) and mixed nanofluid (Al₂O₃+TiO₂-H₂O) as working medium. The feasibility of using Fluent to simulate nanofluid heat pipes was comprehensively analyzed from the visualization analysis of evaporation and condensation process inside heat pipes and the results of the overall thermal parameters. The results show that, from the visualization point of view, the simulated nephogram can reflect the phase transition process in the heat pipe with time. However, there is still a 3% error between the specific simulation value and the corrected experimental value, indicating that there are unconventional factors affecting the simulation results. It is feasible to use the VOF model to simulate the nanofluid heat pipe in numerical law and visualization analysis, but it is still necessary to combine other simulation methods to study the detailed principle.

A comprehensive review of the research related to geothermal center tubes was provided and their key role were detailed in efficient geothermal heat transfer systems. Firstly, its structural design, such as the influence of center tube type, tube diameter size, tube wall thickness and tube structure on heat transfer efficiency and fluid flow, was discussed to ensure its long-term stable operation. In addition, the influence of material properties, including high temperature resistance, corrosion resistance and good thermal conductivity, on the operation of geothermal systems was analyzed, and the current research status and application examples of centerpipes made of different materials were discussed. Finally, the future development trend of geothermal centerpipe was outlooked, emphasizing the importance of innovative materials and optimal design of manufacturing process in improving the efficiency of geothermal utilization and reducing costs.

Considering the cross sensitivity of strain and temperature in fiber Bragg grating measurement, two types of sensors based on fiber Bragg grating strain and temperature were developed. After removing wavelength drift caused by temperature, the individual changes in fiber Bragg grating strain can be obtained, which solves the problems of complex design structure and inability to compensate for temperature in traditional fiber Bragg grating sensors. The strain sensing capability and temperature sensing characteristics of the sensor were investigated through stress tensile testing and water bath testing. The experimental results show that the sensitivity coefficient of the fiber Bragg grating strain sensor is 0.95 pm/με, with a deviation of only 2.05% from the theoretical strain sensitivity coefficient; In the range of 20~60 ℃, the sensitivity of the temperature sensor reaches around 20pm/ ℃, which is 2.2 times higher than that of unpackaged bare fiber Bragg gratings. Compared with the sensitivity coefficient before temperature compensation, the coefficient after compensation is significantly improved, effectively achieving the goal of temperature compensation and providing a more reliable basis for strain monitoring in the field of civil engineering.

Conglomerate reservoir is an important type of unconventional oil and gas reservoir. During the development process, it is found that the nature of the cementation surface between the gravel and the matrix affects the fracture propagation behavior. In order to clarify the effect of cementation strength on crack growth, a numerical model of conglomerate uniaxial compression was established by using PFC2D discrete element package, and four stages of crack growth and micro-fracture mechanism were studied. The results show that the mechanical properties of conglomerate gradually change from plastic to brittle with the increase of cementation strength, and the critical cementation strength ratio is 0.3.The influence of cementation strength on crack growth is mainly in the elastic stage and the stable crack growth stage. Under weak cementation (CSR<0.3), isolated shear cracks occur on the gravel edges in the elastic stage, and shear crack networks are connected in the stable growth stage. Under strong cementation (CSR>0.3), there are almost no cracks in the elastic stage of the gravel edge, and only sporadic isolated tensile cracks in the stable crack growth stage. The additional stress caused by the disharmony of deformation between gravel and matrix under weak cementation is the reason that the edge of gravel is the first to break and form an isolated fracture. These results indicate that weak cementation is conducive to the formation of complex fracture networks. A reference is provided for revealing the fracture propagation law of conglomerate reservoir.

Based on 30 provincial-level panel data in China from 2013 to 2022, Focusing on the mechanisms research, AI affects employment in the service sector was examined. The results show that the impact of AI on service industry employment from a national perspective roughly shows a U-shaped relationship and still holds after considering indigeneity issues and robustness tests. In terms of micro-mechanisms, AI positively promotes service industry employment by affecting the structure of the service industry. The extended discussion suggests that the application of AI has a significant positive employment promotion effect on middle-skilled and high-skilled labor force employment in the service industry. In addition, the potential of modern service industry to absorb labor force employment continues to rise compared with traditional service industry. The extended discussion shows that the application of AI has a significant positive effect on the employment of middle-skilled and high-skilled labor in the service industry. In addition, the absorption potential of the modern service industry compared with the traditional service industry for the employment of the labor force continues to rise.

Digital economy has become a new economic form to create social wealth, and ESG (environmental, social and governance) as an enterprise evaluation standard highly consistent with the concept of sustainable development has also been widely concerned at home and abroad. In order to meet the needs of green high-quality development of enterprises under the new normal, the relevant data of listed companies of China’s Shanghai and Shenzhen A-share intelligent manufacturing equipment enterprises from 2009 to 2021was selected, and the impact and mechanism of digital level on enterprise ESG performance was verified through regression analysis. The empirical results show that the digital level of intelligent manufacturing equipment enterprises can significantly and positively affect the ESG performance of enterprises, and its impact path is to improve the quality of internal control and reduce financing constraints. The digital level of non-state-owned enterprises and non-heavily polluting enterprises has a stronger positive impact on ESG performance. From the perspective of enterprise digitalization, theoretical support is provided for improving the performance of ESG in Chinese enterprises and promoting the development path of ESG in China.

Under the “dual carbon” target, the topic of corporate ESG information disclosure has become a hot research topic nationwide. As China is still in the initial stages of sustainable disclosure, most research solely concentrates on the rating of ESG information, overlooking the quality of ESG information disclosure. Therefore, from the perspective of sustainable disclosure standards for enterprises, taking the construction machinery industry as the research sample, a fuzzy comprehensive evaluation model was adopted to establish a quality evaluation system for enterprise ESG information disclosure, in order to assist the subsequent application of sustainable disclosure standards for enterprises and further standardize ESG information disclosure work in China’s industry.

With high-quality development of economy, green innovation has emerged as a crucial driving force for fostering sustainable and healthy economic growth. Digital industry agglomeration can promote the agglomeration of factor resources and industrial transformation and upgrading, thereby enhancing regional green innovation efficiency. Based on the panel data of 30 provinces(due to the lack of data, the statistical data mentioned here do not include the Tibet Autonomous Region, the Hong Kong Special Administrative Region, the Macao Special Administrative Region and Taiwan Province)from 2012 to 2021, the Super-SBM model and location entropy were used to measure the evaluation indicators of green innovation efficiency and digital industry agglomeration, subsequently, the effects and mechanism of digital industry agglomeration on green innovation efficiency were examined. The results indicate that digital industry agglomeration contributes to the enhancement of regional green innovation efficiency. Due to the differences in geographical location and technology input level, the enhancement effect of digital industry agglomeration on regional green innovation efficiency is more significant in the eastern region and high-tech input provinces. Mechanism analysis shows that digital industry agglomeration can improve regional green innovation efficiency by promoting the upgrading of industrial structure. In view of this, each province should actively promote the development of digital industry clusters, scientifically formulate differentiated digital industry development strategies and promote the upgrading of industrial structure, so as to help the steady improvement of regional green innovation efficiency.

In the digital economy era, online markets are crucial venues for resource allocation, and optimizing resource allocation is a vital pathway to promote industrial transformation and upgrading. Based a two-way fixed effects model, a mediation effect model and a threshold effect model, the impact and underlying mechanisms of the development of online markets on the optimization of industrial structure in China were analyzed, using data from 288 prefecture-level cities from 2014 to 2021.It is found that the development of online markets significantly enhances the advancement of industrial structure but somewhat inhibits the rationalization of industrial structure. These conclusions remain robust after a series of robustness checks. The mediation effect test results show that the development of online markets can promote the advancement of industrial structure by improving resource allocation efficiency. Further analysis indicates that the promotion of industrial structure advancement by online markets exhibits heterogeneity, being more significant in the eastern and western regions, in areas with larger populations, and in regions with lower levels of digital infrastructure. The threshold model results reveal a marginally increasing nonlinear characteristic in the promotion of industrial structure advancement by the development of online markets. Therefore, to fully leverage the resource allocation role of online markets, it is necessary to further expand the scale of online markets, regulate their operations, define the boundaries of different types of online markets, strengthen market access reviews, enhance the role of data mechanisms, and bolster anti-monopoly and market supervision to encourage more participants. Different regions should be encouraged to adopt differentiated strategies for online market development.

The coordinated development of population and economy is one of the most basic starting points in the study of all population issues. Tuojiang Green Development Economic Belt carries distinct advantages and unique positioning in the construction of “Chengdu-Chongqing economic circle”. Based on regional economics and other theories, taking 6 municipal areas in the basin as the research object, and the effect of population and industry agglomeration from the structural characteristics and interaction mechanism of population and industry agglomeration was discussed. Scientific and reasonable suggestions are provided for the construction of Tuojiang green development economic Belt from the perspectives of industrial structure optimization, regional coordination and green development.