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The article selects relevant data from 283 cities in China from 2000 to 2020 and verifies the impact of the establishment of free trade zones on human capital levels based on the asymptotic PSM-DID model. It is found that the establishment of FTZs can significantly contribute to the improvement of regional human capital levels, but the promotion effect has a certain lag. Finally, the article gives constructive suggestions based on the empirical results. [ABSTRACT FROM AUTHOR]

Taking China's first application of domestic shield tunneling in a water-rich sand layer for crossing a high-speed railway as research background, the influence of changes in the shield tunneling parameters on ground settlement is analyzed based on field tests, and a construction control method suitable for shield tunneling under a risk source in a water-rich sand layer is proposed. The test results show that the use of 10% sodium bentonite as the soil modifier for soil pressure balance shield tunneling into the water-rich sand layer has advantages, while adding 50% loess into the bentonite slurry in the gravel sand layer can greatly improve the impermeability of the soil; the settlement of soil can be effectively reduced by using the special segment with grouting holes for deep grouting and applying the adaptive transformation of the shield cutter. Based on the statistical analysis results, a reasonable range for the cutter head torque, cutter head speed, chamber pressure, bentonite injection volume, and advanced speed in the water-rich sand layer can provide a construction control basis for similar projects and provide data support for the compilation of relevant specifications. [ABSTRACT FROM AUTHOR]

With the rapid development of high-speed rail in China, addressing the issue of safety assurance during the operation of the train is very important. A very important part of a train's power supply system is the pantograph and catenary system, which consists of a pantograph and a catenary. Failure of the pantograph-catenary system can cause significant damage to the normal operation of the train. The dynamic performance of the pantograph-catheter system must be detected in real time during the operation of the train. This paper is based on the study and analysis of pantograph-catheter dynamic performance parameters and developed a system for real-time detection of pantograph-catheter dynamic performance parameters based on a car visual system. The results are as follows: based on this detection method, the visual error is low and the accuracy is high. The machine-based directional height detection module developed in this paper has a good detection effect and high test accuracy; the arcing detection module designed in this paper can effectively detect the arcing and store the arcing pictures and can display the duration of single arcing and the arcing rate of the section in real-time. The practical application effect is good. The results show that the focal length of the camera lens is 16 mm, and the error of the machine vision system is low. The system designed in this paper may make a great contribution to the operation condition monitoring and fault diagnosis of the pantograph-catenary system of a high-speed train in the future. [ABSTRACT FROM AUTHOR]

The development of the new energy vehicle industry is necessary for its advantages of saving energy and reducing greenhouse-gas emissions. However, the industry is currently facing risks with regard to, for example, technology, market, and the policy. Most existing studies of industry risk focused on analyzing and evaluating risk factors and summarizing and interpreting risk phenomena. In this study, systematic classification and quantitative analysis for the risk of the new energy vehicle industry were investigated, in which the entropy weight method and cloud model were combined to evaluate and quantify the industry risk. The formation mechanism of the industry risk from endogenous and exogenous perspectives was analyzed to screen out risk-evaluation factors. Combining the expert-investigation and fuzzy-statistics methods, a risk-evaluation index system with six primary indicators and twenty-four secondary indicators was constructed. On the basis of the entropy weight-cloud model, the risk of the new energy automobile industry of Jiangsu province in July 2019 was evaluated. Results indicated that the impact of exogenous risk on the industry was greater than that of endogenous risk, and industry risk was higher than medium risk, which was close to a higher medium level. A series of suggestions are given for preventing industry risk, such as improving the industry's own ability to resist risk and building the industry's soft environment. [ABSTRACT FROM AUTHOR]

Based on the data relevant to China's tourism industry and ecological environment from 2005 to 2018, the entropy method and the coupling coordination degree model were used to analyze the coupling degree and coupling coordination degree of the tourism industry's development and the ecological environment, and the GM (1.1) gray model was used to predict these values in the future. The model provided predictions and illustrated the trend in the changes in the degree of coordination between the development of China's tourism industry and the ecological environment for the next five years. The results show the following. (1) The coupling degree between China's tourism industry and the ecological environment was between 0.3 and 0.5. It was in the low-level coupling stage in 2005 and 2006 and generally low in 2005–2009, lower than the average level of 0.4204. In 2018, the coupling degree between the development of China's tourism industry and the ecological environment was mainly in a stage of antagonism, reaching a peak of 0.4998 in 2013. The coupling degree declined slightly from 2013 to 2015 and then began to show an upward trend again in 2016. (2) The average coupling coordination level of China's tourism industry development and ecological environment was 0.4266, which is in the medium coupling coordination stage. From 2007 to 2013, it was mainly in the phase of moderate coupling and coordination and high coupling and coordination from 2014 to 2018. (3) From the prediction results, the coupling degree will enter the coupling degree running-in stage in 2021 and the extreme coordination stage in 2023, but the coupling growth level during the running-in period will be significantly lower than the coupling coordination degree. Coordinated development of the two systems will take a long time, and active economic policies need to be adopted to promote their coordinated development. [ABSTRACT FROM AUTHOR]

Based on the data of China's ecological environment from 2006 to 2018, the paper uses the super-efficiency DEA and Malmquist index methods to evaluate China's ecological welfare performance from a static and dynamic perspective. Based on this, the Theil index is used to analyze the group's ecological welfare performance. The internal and intergroup differences show that, from the static evaluation results, China's ecological welfare performance is in a situation of "high in the east, low in the west, and average in the central region." There is not much difference between the eastern and central regions, while the ecological welfare performance in the western region is low. From the results of dynamic evaluation, the overall level of regional ecological welfare performance in China has improved in recent years, and the average Malmquist index has exceeded 1, indicating that the growth pattern of ecological welfare performance has shifted to high quality, but the degree of increase in each region is different. There is still much room for improvement in ecological welfare performance; from the perspective of intragroup and intergroup differences, the intragroup differences and intergroup differences in the three major regions have generally maintained a continuous downward trend, and the contribution of the differences in ecowelfare performance between group rate has a clear advantage. Finally, corresponding suggestions are put forward based on the empirical results of the paper. [ABSTRACT FROM AUTHOR]