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The purpose of this paper is to study the high temperature oxidation behavior of Ti and C-added FeCoCrNiMn high entropy alloys (HEAs).

Cyclic oxidation method was used to obtain the oxidation kinetic profile and oxidation rate. The microstructures of the surface and cross section of the samples after oxidation were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM).

The results show that the microstructure of the alloy mainly consisted of FCC (Face-centered Cubic Structure) main phase and carbides (M₇C₃, M₂₃C₆ and TiC). With the increase of Ti and C content, the microhardness, strength and oxidation resistance of the alloy were effectively improved. After oxidation at a constant temperature of 800 °C for 100 h, the preferential oxidation of chromium in the chromium carbide determined the early formation of dense chromium oxide layers compared to the HEAs substrate, resulting in the optimal oxidation resistance of the TC30 alloy.

More precipitated CrC can preferentially oxidize and rapidly form a dense Cr₂O₃ layer early in the oxidation, which will slow down the further oxidation of the alloy.

The aim of this paper was to study the initial corrosion behavior of copper in the substations of Zhanjiang and Zhuhai.

The copper exposed at the substation of Guangdong coastal region in southern China for up to 12 months. The rust layer formed on the copper has been examined by scanning electron microscopy, X-ray energy spectrum, X-ray diffraction and electrochemical polarization techniques.

The corrosion weight loss of copper at Zhanjiang exposure site is a little more serious than that at Zhuhai exposure site in every exposure period. The corrosion products of copper have different changes in color and composition at the two exposure sites. The tensile strength of copper has a slight decrease after one-year exposure.

The atmospheric exposure experiments of copper in the substations of Zhanjiang and Zhuhai have been adopted for the first time. The corrosion behavior of copper was investigated, and it can provide reference for material selection of the substation.

From a supply chain perspective, logistics firms collaborate with other supply chain members to extend their business scope. Investment in circular economy projects in the supply chain can not only broaden the scope of business but also increase the value of the entire supply chain. Third-party logistics companies are gradually participating in the construction and operation of many circular economy projects. How to coordinate multiple circular economy supply chain projects is at the core of its operation.

This paper first analyzes some typical supply chain projects in China and summarizes the main features of these projects. Secondly, considering the benefits of the project and the stakes of each project, a multi-stage stochastic programming model is established. Finally, Cplex, nested decomposition, LocalSolver and other methods are adopted to simulate and analyze the model.

The final experimental results find that the importance of coordinating multiple circular economy supply chain projects to increase the value of the entire supply chain. The multi-stage stochastic programming model presented in this research can provide a useful tool for logistics enterprises and third-party logistics companies to optimize their investment decisions and maximize their profits in the context of a circular economy.

There are still some limitations to this study; for example, it is limited to the analysis of circular economy supply chain projects in China. The study focused on third-party logistics companies, and other enterprises in the circular economy supply chain were not considered. The research also assumed that the benefits of each circular economy project and the stakes of each project were known, which may not always be the case in real-world scenarios.

This manuscript found that investing in other circular economy projects in the supply chain can broaden the scope of business and increase the value of the entire supply chain. Third-party logistics companies are gradually participating in the construction and operation of many circular economy projects, such as recycling and repurposing initiatives. It highlights the importance of coordinating multiple circular economy supply chain projects to increase the value of the entire supply chain. The multi-stage stochastic programming model presented in this research can provide a useful tool for logistics enterprises and third-party logistics companies to optimize their investment decisions and maximize their profits in the context of a circular economy.

This paper aims to clarify the spatial connection characteristics and organization mode of logistics economy of 21 cities in Guangdong Province under the background of the integrated development of Guangdong, Hong Kong and Macao Bay area, and explore the spatial development characteristics and influencing factors of logistics economy in Guangdong Province.

This paper constructs the development level model of urban logistics economy in Guangdong Province from three aspects: demand level, supply level and support level, and uses the entropy weight method to measure the development level index of urban logistics economy in Guangdong Province. Then, the traffic accessibility index model is used to measure the traffic accessibility index between cities in Guangdong Province. Finally, using the social network analysis method, combined with the development level index of urban logistics economy in Guangdong Province and the urban traffic access index in Guangdong Province, this paper analyzes the spatial connection characteristics and influencing factors of logistics economy network in Guangdong Province.

There are regional differences in the development level of logistics economy in Guangdong Province; The overall network density of its logistics economic connection is large, but there is an imbalance in the network structure, and the core edge phenomenon is obvious; Logistics economic space presents the characteristics of double core development.

Because the research object is the spatial connection characteristics of logistics economy in Guangdong Province, the research results may lack universality. Therefore, researchers are encouraged to put forward further tests.

By studying the spatial connection mode of logistics economy in 21 cities in Guangdong Province, China, this paper promotes the original methods and empirical contributions, and constructs the research framework of spatial relationship of logistics economy. This research framework is universal to a certain extent.

This paper is conducive to promoting the integrated development of logistics economy in Guangdong Province and improving the balance of regional development of logistics economy.

Firstly, this study provides a new perspective to understand the spatial relationship and spatial spillover of logistics economy from relational data rather than attribute data. Secondly, This study enriched and broadened the research topic of spatial correlation of logistics economy. Thirdly, this research aims to promote the original methods and empirical contributions. Specifically, this study establishes a comprehensive research framework on the spatial network structure of logistics economy.

This paper aims to study the use of electrochemical noise (EN) technology in the corrosion continuous monitoring of stainless steel (SS) in an atmospheric environment.

An EN electrode was designed and fabricated to acquire the EN of 304 SS in the atmospheric environment. The statistical analysis and shot noise analysis were used to analyze the EN, and the surface morphology analysis of 304 SS was used to verify the EN analysis results.

The activation state, passive film formation and pitting corrosion of 304 SS can be clearly distinguished by the amplitude and frequency change of EN. The metastable pitting corrosion and steady-state pitting corrosion can be identified with the shot noise parameters q and fn. Under the existence of chloride ion, the stability of 304 SS passive film decreases and the steady-state corrosion pits of 304 SS are more likely to form with the reduction of thin electronic layer (TEL) pH. The critical TEL pH of 304 SS corrosion is a pH between 3 and 4.

In an atmospheric environment, the EN technology was used in the corrosion continuous monitoring of SS.

This study aims to explore the compressive behavior of hollow triply periodic minimal surface (HTPMS) cellular structures by selective laser melting (SLM).

This study presents a design method for gyroid hollow triply periodic minimal surfaces (G-HTPMS) and primitive hollow triply periodic minimal surfaces (P-HTPMS) cellular structures, and SLM technology was applied to manufacture these cellular structures. Compressive behaviors and energy absorption behaviors of hollow cellular structures were researched in this study.

Compared with normal gyroid triply periodic minimal surfaces (G-TPMS) and normal primitive triply periodic minimal surfaces (P-TPMS), the G-HTPMS and P-HTPMS have higher elastic modulus, plateau stress and effective energy absorption under uniaxial compression. The hollow design in HTPMS can enhance the mechanical properties and energy absorption of the cellular structure. Finite element analysis also demonstrates that the hollow design can reduce stress concentration, which improved the compressive curves from a severely fluctuating state to a relatively flat state and reduces fracture. According to compressive behaviors, G-TPMS and G-HTPMS are the bending-dominated cellular structures with strain hardening characteristics, and P-TPMS and P-HTPMS are the stretching-dominated cellular structures with strain softening characteristics.

This research provided a design method for HTPMS, and it was proved that the mechanical properties increased by hollow design inspired by bamboo.

To cope with the severe situation of the global climate, China proposed the “30 60” dual-carbon strategic goal. Based on this background, the purpose of this paper is to investigate scientifically and reasonably the interprovincial pattern of China’s power carbon emission intensity and further explore the causes of differences on this basis.

Considering the principle of “shared but differentiated responsibilities,” this study measures the carbon emissions within the power industry from 1997 to 2019 scientifically, via the panel data of 30 provinces in China. The power carbon emission intensity is chosen as the indicator. Using the Dagum Gini coefficient to explore regional differences and their causes.

The results of this paper show that, first, China’s carbon emission intensity from the power industry overall is significantly different. From the perspective of geospatial distribution, the three regions have unbalanced characteristics. Second, according to the decomposition results of the Gini coefficient, the overall difference in power carbon emission intensity is generally expanding. The geospatial and economic development levels are examined separately. The gaps between the eastern and economically developed regions are the smallest, and the regional differences are the source of the overall disparity.

Further exploring the causes of differences on this basis is crucial for relevant departments to formulate differentiated energy conservation and emission reduction policies. This study provides direction for analyzing the green and low carbon development of China’s power industry.

As an economic indicator of green and low-carbon development, CO₂ intensity of power industry can directly reflect the dependence of economic growth on the high emission of electricity and energy. and further exploring the causes of differences on this basis is crucial for relevant departments to formulate differentiated energy conservation and emission reduction policies.

For a long time, with the rapid economic development, resulting in the unresolved contradiction between low energy efficiency and high carbon emissions. To this end, scientifically and reasonably investigating the interprovincial pattern of China’s power carbon emission intensity, and further exploring the causes of differences on this basis, is crucial for relevant departments to formulate differentiated energy conservation and emission reduction policies.

Third, considering the influence of spatial factors on the convergence of power carbon emission intensity, a variety of different spatial weight matrices are selected. Based on the β-convergence theory from both absolute and conditional perspectives, we dig deeper into the spatial convergence of electricity carbon emission intensity across the country and the three regions.

This study aims to understand the epistemic foundation of the classification applied in the first Chinese library catalogue, the Seven Epitomes (Qilue).

Originating from a theoretical stance that situates knowledge organization in its social context, the study applies a multifaceted framework pertaining to five categories of textual data: the Seven Epitomes; biographical information about the classificationist Liu Xin; and the relevant intellectual, political, and technological history.

The study discovers seven principles contributing to the epistemic foundation of the catalogue's classification: the Han imperial library collection imposed as the literary warrant; government functions considered for structuring texts; classicist morality determining the main classificatory structure; knowledge perceived and organized as a unity; objects, rather than subjects, of concern affecting categories at the main class level; correlative thinking connecting all text categories to a supreme knowledge embodied by the Six Classics; and classicist moral values resulting in both vertical and horizontal hierarchies among categories as well as texts.

A major limitation of the study is its focus on the main classes, with limited attention to subclasses. Future research can extend the analysis to examine subclasses of the same scheme. Findings from these studies may lead to a comparison between the epistemic approach in the target classification and the analytic one common in today's bibliographic classification.

The study is the first to examine in depth the epistemic foundation of traditional Chinese bibliographic classification, anchoring the classification in its appropriate social and historical context.

The purpose of this paper is to explore the ways to encourage members in QQ knowledge-communication groups to persistently share knowledge in terms of contexts and autonomous motivations.

Based on self-determination theory, three important contextual factors of QQ knowledge-communication groups were selected as exogenous variables and three typical autonomous motivations as mediating variables to construct a knowledge-sharing model. Internet questionnaire surveys and data collection were conducted to test proposed hypotheses by means of structural equation modeling with AMOS.

Reciprocity, learning, and altruism have significant positive influence on persistent sharing willingness, and the degree to which each factor influences persistent sharing willingness differs considerably. Autonomy support, perceived usefulness, and relatedness support have no significantly direct influence on persistent sharing willingness, but they indirectly influence the persistent sharing behaviors by the mediating effect of different autonomous motivations.

This study contributes theoretically and practically. First, the results suggest that a particular motivation in different contexts has a different degree of autonomy. In addition, explanations are offered for the phenomenon that suggest that controlled motivations directly affect autonomous motivations. It was found that the contextual factors of competence support and relatedness support also have influence on different autonomous motivations, and hence encourage knowledge-sharing behaviors. Specific suggestions for QQ group managers and information seekers are proposed.