[Objective] As an important application scenario of the low-altitude economy, drone delivery has been developing rapidly, placing higher demands on the integrated utilization of air and ground resources. Therefore, it is necessary to identify the organizational characteristics and key challenges of air-ground coordination based on practical cases, providing references for the coordination and shared use of airspace resources. [Methods] This study took Shenzhen as a case study, selecting two representative companies, S and M. Through continuous field surveys and in-depth interviews conducted from July 2024 to April 2025, it systematically analyzed their operational models, spatial layouts, and flight route planning. [Results] (1) The existing air-ground coordination operational models were shaped by business model requirements, forming two distinct models: an interconnected direct model anchored at network nodes, and an end-responsive model anchored at commercial districts. (2) The different operational models led to significant differences in air-ground coordination layouts: Company S established a multi-node, coordinated, and large-scale transport network by relying on self-operated distribution centers and delivery outlets, while Company M developed a dense, single-center service system focused on commercial districts. (3) Differences in spatial layout further influenced the interaction between flight routes and ground networks. Company S generally located its facilities in open areas such as logistics parks, resulting in higher flexibility in flight route planning. Company M operated at altitudes lower than densely built urban high-rise buildings, facing more complex spatial constraints. [Conclusion] Low-altitude delivery systems effectively leverage the flexibility and efficiency of drones, expanding service coverage and improving overall delivery efficiency through integration with ground transportation systems. In the future, it is essential to enhance the coordination and shared use of airspace resources, advance the deep integration of drone delivery with ground transportation infrastructure, and address coordination and connectivity challenges such as gaining access to communities and buildings.

With the continuous improvement of China’s highway network construction and the ongoing expansion of transportation infrastructure, traditional highway inspection methods can no longer meet the practical requirements of modern highway maintenance and management in terms of efficiency, safety, and coverage. Low-altitude unmanned aerial vehicle (UAV) remote sensing technology, with its advantages of high mobility, low cost, and strong data acquisition capability, provides a novel technical solution for highway inspection. Therefore, this study first systematically reviews the current application status and development trends of low-altitude UAV remote sensing technology in highway inspection, and conducts an in-depth analysis of its application progress in four typical scenarios: intelligent detection of pavement distress, bridge distress identification and vibration monitoring, slope stability monitoring and risk early warning, and rapid emergency response and disaster assessment. Focusing on the “low-altitude flight—distress identification—real-time computing—3D visualization” technical pathway, this study primarily discusses key technical methods such as low-altitude inspection route planning, automatic pavement distress identification, edge computing for real-time processing, and 3D reconstruction with digital twin. Additionally, this study elaborates on the practical challenges faced by existing low-altitude remote sensing technology in highway inspection applications, including insufficient data stability and standardization, lack of multi-source data fusion and integrated application, mismatch between model accuracy and industry requirements, and issues related to policies, regulations, and safety management. Finally, from the three dimensions of deepening technical applications, breakthroughs in key technologies, and development of standardized regulations, this study proposes the key directions for the future development of low-altitude remote sensing technology in highway inspection, providing theoretical references and technical support for advancing highway maintenance and management toward intelligent, information-based, and refined models.

With advancements in low-altitude technology and reforms in the airspace management, human activity is expanding from the ground into the low altitude space. This can unlock new dimensions of value in low-altitude resources and accelerate the development of the low-altitude economy. As a representative example of new quality productive forces, the low-altitude economy has become a key component of the national strategy for high-quality development. In response to the new demands and tasks of efficiently utilizing low-altitude resources and ensuring the sustainable development of the low-altitude economy, it is essential to leverage geography’s unique disciplinary strengths in analyzing spatial heterogeneity, systemic interactions, and dynamic evolution patterns. By conducting systematic research on theory, policy, industry, and application, it provides crucial support for addressing challenges such as resource allocation, industrial layout, and spatial governance in the development of the low-altitude economy.

[Objective] Unmanned aerial vehicles (UAV) represent a key development direction in global strategic emerging technologies and one of the highly competitive high-tech products in China. Revealing the global UAV trade network and its influencing factors can provide decision-making support for optimizing the global trade pattern and helping China avoid potential trade risks. [Methods] Complex network analysis, exponential random graph model, and network vulnerability simulation model were employed to reveal the topological characteristics of the global UAV trade network from 2022 to 2024, analyze the influencing factors of the network, and simulate the network vulnerability under different impact scenarios. [Results] (1) From 2022 to 2024, global UAV trade volume increased from 4.232 billion USD to 12.665 billion USD, an increase of 1.99 times. Changes in trade volume were linked to the global geopolitical situation and trade control policies. (2) Overall, both the number of participating economies and trade connections in the global UAV trade network increased, with a significant small-world phenomenon. At present, western economies such as Ukraine and the United States have played an increasingly prominent role as importers, while the mainland of China and Hong Kong of China gradually dominated the export pattern. Malaysia’s influence on trade networks rapidly expanded. The network evolved from a single-core structure to a dual-core structure, forming a super cluster centered on the mainland of China and Hong Kong of China, covering 75% of the global economies and nearly 80% of the trade volume. (3) Reciprocal relationships served as a critical endogenous structure driving the expansion of the network. Economies with high openness, favorable institutional environment, advanced technological levels, and strong economic strength shaped the core structure of the network through their significant advantages in both imports and exports. The influence of geographical distance and geopolitical relationships on the establishment of trade connections was limited. (4) Under the influence of the transmission-based trade network motif structure, the influence of the withdrawal of different types of economies on network efficiency followed the order: intermediary type > comprehensive type > export-oriented type > import-oriented type. The influence of export restrictions by export-oriented type economies on network efficiency was greater than that of import restrictions by import-oriented type economies. [Conclusion] From 2022 to 2024, the global UAV trade scale has doubled, and changes in the network structure are linked to the international situation. China has a scale advantage and concentrated risks in the global UAV trade market.

As human activities extend from surface space into the three-dimensional low-altitude space, the value of low-altitude airspace resources has been activated, thereby promoting the development of the low-altitude economy. Due to the complex interactions among low-altitude airspace, the surface, and human activities, it is imperative to leverage the disciplinary advantages of geography to investigate the low-altitude human-environment system, providing guidance for the sustainable development of the human-environment system and the scientific implementation of the low-altitude economy. Through conceptual analysis, literature review, and theoretical interpretation, this study clarified the conceptual connotation and geographical characteristics of the low-altitude economy, analyzed the elemental structure and theoretical framework of the low-altitude human-environment system, and proposed key research topics for future focus. The low-altitude airspace evolved from a simple atmospheric concept into a resource element with natural, social, and economic attributes. The complex low-altitude—surface—human activity system formed by the interaction between low-altitude human activities and low-altitude geographical environments emerged as a new subject of human-environment system research. This study constructed the concept of the low-altitude human-environment system, which was composed of low-altitude resources, low-altitude geographical environments, low-altitude human activities, and their interactions. Among them, low-altitude resources were centered on the development and utilization of low-altitude airspace and included various tangible and intangible resources formed through the interaction between the surface and human activities. Their capacity measurement served as the foundation for the development of the low-altitude economy. The low-altitude geographical environment exhibited regional, complex, dynamic, and comprehensive characteristics due to factors such as boundary-layer meteorology, underlying surface conditions, topography, surface structures, ecological environments, and human activities. Low-altitude human activities referred to a series of actions undertaken by humans for survival, development, and improvement of living standards, centered around low-altitude resources, which generated economic, social, and environmental effects. The interactions between humans and environment were critical in driving the dynamic evolution and coupled coordination of the low-altitude human-environment system.

[Objective] In the context of China’s “dual-carbon” goals and the ecological civilization development, the management of non-hazardous industrial solid waste (NHIW) in China faces new opportunities and challenges. This study aims to systematically review China’s policy texts on NHIW management from 2001 to 2024 and identify their evolutionary stages and main characteristics, thereby providing references for improving policies on comprehensive industrial resource utilization and enhancing environmental governance efficiency. [Methods] A total of 303 policy documents on NHIW management issued by central government from 2001 to 2024 were selected as the research samples. Through quantitative text analysis methods such as word frequency analysis and keyword co-occurrence analysis, combined with punctuated equilibrium theory, this study systematically investigated the evolutionary characteristics of policy objectives, number of policies, keywords, and issuing entities. [Results] (1) China’s policies on NHIW management from 2001 to 2024 could be divided into four stages: initial prevention-oriented and system-building efforts, steady advancement toward circular economy and ecological civilization, strengthened regulation and policy innovation, and a transition toward green, low-carbon, and high-quality development. (2) Across these stages, policy objectives were dynamically adjusted, governance tools were diversified, inter-entity collaboration was strengthened, and policy themes shifted from simple pollution control to comprehensive resource utilization and green development. [Conclusion] China’s policies on NHIW management have undergone a significant evolution from end-of-pipe pollution control to source prevention, and from fragmented management to systemic governance. Future efforts should focus on refined management, multi-department coordination, and innovation-driven strategies to better address resource and environmental pressures and carbon reduction demands, thus facilitating the realization of a Beautiful China and the sustainable development goals.

[Objective] Under the urgent needs of global warming and energy structure transformation, the development of low-altitude economy has become an important path to promote the green and low-carbon transformation in the transportation sector. As a new solution for low-altitude traffic, the large-scale application of electric vertical take-off and landing vehicle (eVTOL) needs to systematically analyze the “demand-technology” coordination mechanism of its scene application. However, how to deconstruct the adaptation logic of scenario demand and technology supply, and accurately identify the interaction mechanism between market preference and technology bottleneck is the focus of attention. By quantifying the characteristics of market demand and the trend of technology supply, it can provide theoretical support for policy formulation and industrial layout. [Methods] This study conducted a meta-analysis of published eVTOL-related literature to examine the influence mechanisms of variables such as passenger age, gender, and attitude on eVTOL attractiveness and scenario-specific moderating effects. Latent Dirichlet allocation (LDA) topic modeling was applied to extract effective patent texts related to eVTOL from the incoPat database, identifying the evolutionary trends of technological topics. [Results] (1) On the demand side, in terms of the impact mechanism, passengers’ attitudes and family monthly income significantly positively drive eVTOL. Attractiveness, travel cost and time negatively inhibit eVTOL attractiveness ; as far as the moderating effect is concerned, the influence of passenger attitude in urban scenes is the most sensitive. In the airport scene, the most obvious is the positive impact of passenger age and family monthly income. In the scenic spot scene, the influence of passengers’ attitude and travel cost is the most significant. (2) On the supply side, the evolution of patent topics demonstrated a three-stage pattern: the technology incubation stage focused on comprehensive technological deployment in urban scenarios, the technology deepening stage shifted toward systematic breakthroughs in endurance bottlenecks, and the intelligent transformation stage prioritized in-depth expansion of intelligent capabilities. [Conclusion] (1) eVTOL attractiveness is significantly and positively driven by attitude and income, yet negatively constrained by travel cost and time. The influence mechanisms exhibit scenario heterogeneity—airport scenarios highlight time-value premium effects, while tourism scenarios are primarily driven by experience value. (2) Technological evolution follows a progressive pattern of “basic architecture construction→endurance bottleneck breakthrough→intelligent system advancement,” demonstrating coordinated co-evolution with scenario demands.

[Objective] To address the technological management challenges posed by the complexity, disruptiveness, elevational characteristics, and foresight characteristics of low-altitude technological innovation, this study aims to reveal the internal and external coordination mechanisms of enterprises’ low-altitude technological innovation, providing theoretical and practical guidance for the technology layout and policy-making of emerging industries. [Methods] By integrating dynamic capabilities theory and resource dependence theory, 296 A-share listed companies in China engaged in low-altitude technological innovation in 2023 were selected as the samples. Using fuzzy-set qualitative comparative analysis (fsQCA) and machine learning methods, the multiple configuration paths of enterprises’ low-altitude technological innovation were explored. [Results] (1) Five equivalent configurations of low-altitude technological innovation were identified: policy-guided, university-enterprise dependent, university-government dependent, collaborative innovation, and independent breakthrough models. The core driving mechanism was reflected in the nonlinear synergy and dynamic transformation between dynamic capabilities and external resources. (2) Contingency analysis indicates that when enterprises exhibit higher levels of digital-intelligent transformation, organizational redundancy, and larger size, this influences the selection of innovation models by strengthening internal capabilities or restructuring external dependencies. (3) Machine learning results validated the robustness of the fsQCA results and highlighted the critical roles of innovation capability, government-enterprise relationships, and university-enterprise cooperation. [Conclusion] Enterprises’ low-altitude technology innovation requires precise alignment and effective coordination between internal capabilities and external resources, comprehensively considering contingency factors, dynamically and flexibly selecting suitable innovation models based on their resource endowments and external environment.

[Objective] Improper disposal of end-of-life power batteries may lead to soil and water pollution. Scientific evaluation of the environmental impacts during the regeneration and utilization processes of these batteries and the identification of key environmental impact factors and stages are essential for improving the resource recovery efficiency and promoting the achievement of the “dual carbon” goal. [Methods] Under such circumstances, the life cycle assessment (LCA) method was employed to quantitatively analyze the environmental impacts of two recycling processes for end-of-life batteries: mechanical-physical recovery and wet recovery. This study innovatively specified five treatment stages, and three endpoint and eighteen midpoint environmental impact types were considered. [Results] (1) The environmental impact values of both recycling processes were negative, indicating that the recycling of end-of-life power batteries could effectively mitigate environmental impacts from a life cycle perspective. The mechanical-physical recovery exhibited better environmental performance compared to the wet recovery, with both processes demonstrating the greatest mitigation effects on marine ecotoxicity, accounting for 51.4% and 53.2%, respectively. (2) From the perspective of endpoint environmental impact, the recycling of end-of-life power batteries exhibited markedly higher mitigation effects on resource depletion (97.3%) than on human health (2.6%) and ecosystem (0.1%). (3) The battery crushing and sorting stage and the electrode sheet processing stage were identified as the primary contributors to the environmental impacts, each accounting for about 35.7% of the total impacts. [Conclusion] Sensitivity analysis shows that reducing material inputs and improving the recycling rate of recycled products have the most significant impacts on life cycle environmental effects, while variations in electricity input show relatively minor effects. It is recommended to further strengthen the cascading utilization of end-of-life power batteries and improve the output rate of recycled products to reduce their environmental impacts.

[Objective] How to advance digital tourism while preserving cultural resources has become a pressing issue for the sustainable development of traditional villages in the framework of Digital China and the Network Power strategy. Research on the construction of digital tourism scenarios in traditional villages is conducive to promoting the coordination between digital protection and village development. [Methods] Guided by scenario theory, methods such as induction and synthesis were employed to investigate the conceptual characteristics and implementation framework of digital tourism scenarios in traditional villages. The digital tourism scenario framework was constructed by taking Zhangguying Village as an example. [Results] (1) The digital tourism scenario of traditional villages was a virtual scenario built by collecting and storing tourism resources such as traditional village architectural landscapes, history and culture, festival activities, and folk customs, and using a virtual simulation platform. (2) The construction of digital tourism scenarios in traditional villages involved four core steps: Identification of scenario elements, collection and preservation of tourism resources, construction of digital tourism scenarios, and presentation and dissemination of tourism scenarios. The final output comprised five key digital tourism scenarios: AI-powered audio guides, virtual activity experiences, digital cultural education, village cultural IPs, and virtual tourism communities. (3) The tourism scenario elements of Zhangguying Village could be collected and stored from the aspects of space, physical structures, diverse groups of people, activities, and cultural values. The digital tourism scenarios of traditional villages in Zhangguying Village could be displayed and disseminated through PC network platforms, mobile intelligent terminals, and virtual tourism experience halls. [Conclusion] Research on the construction of digital tourism scenarios in traditional villages should actively integrate new technologies, new methodologies, and new thinking. It should address the human-land relationship in the information age, and focus on digital technical barriers and issues of authentic presence in scenario realization. Additionally, external support mechanisms require enhancement to achieve innovation through the integration of digitalization and practical applications.

[Objective] As an important support for low-altitude flight activities, the development of the unmanned aerial vehicle (UAV) industry is closely linked to the low-altitude economy. This study aims to identify the spatial distribution patterns and coordinated relationships of upstream, midstream, and downstream enterprises in the UAV industry chain, providing references for optimizing industrial spatial layout and promoting high-quality development of the low-altitude economy. [Methods] Based on enterprise big data, this study constructed a comprehensive database of operational UAV enterprises as of December 31, 2024, covering the upstream, midstream, and downstream sectors of the UAV industry chain through keyword search and data cleaning. On this basis, spatial analysis methods were used to identify spatial distribution characteristics of UAV enterprises and coordinated relationships among upstream, midstream, and downstream sectors. [Results] (1) In China’s UAV industry, the upstream sector, encompassing raw material suppliers, component manufacturers, and core system developers, accounted for the largest proportion of enterprises. This was followed by downstream service providers, while midstream UAV manufacturers constituted the smallest proportion. Spatially, the distribution exhibited a pattern of “dense in the east and sparse in the west, more in the south and fewer in the north”. The Pearl River Delta exhibited the highest density, followed by the Yangtze River Delta and the Chengdu-Chongqing regions. (2) Upstream and midstream enterprises showed strong spatial clustering, with upstream enterprises having relatively higher clustering coefficients. Downstream enterprises were market-oriented, and their regional distribution showed relatively smaller differences. (3) Based on the distribution of upstream, midstream, and downstream enterprises in each city’s industry chain, cities could be categorized into four types: coordinated, demand-driven, guided, and cultivated. Coordinated cities had relatively complete industrial chains and significant developmental advantages. Demand-driven and guided cities had advantages in certain segments of the industry chain, but also faced certain shortcomings. Most cities were still in the cultivation stage, with a relatively small number of enterprises across the upstream, midstream, and downstream sectors. [Conclusion] The development of the UAV industry varies across cities. Coordinated cities with relatively complete industry chains should serve as the core hubs for building globally competitive industrial clusters. Demand-driven and guided cities should strengthen and supplement their industry chains, while cultivated cities with weaker foundations should leverage local characteristics and advantages to unlock industrial potential. Overall, development strategies should be tailored to local conditions.

[Objective] Tourism information flow plays a strong guiding role in tourist behavior. Research on the tourism information flow networks within urban agglomerations is crucial for the development of regional tourism in the era of digital economy. [Methods] Using big data analysis from Baidu Index and social network analysis (SNA) method, six urban agglomerations in the east coast of China were taken as examples. Their characteristics and patterns of tourism information flow from 2012 to 2022 were explored, and the driving factors of these networks were further analyzed. [Results] (1) Distinct spatial differentiation was observed in the field strength of tourism information flow within urban agglomerations. Cities with higher development levels exhibited greater agglomeration field strengths, while those rich in tourism resources demonstrated larger diffusion field strengths. (2) The temporal variations of tourism information flow volume within urban agglomerations generally exhibited three stages: rapid growth, slow growth, and rapid decline. The outflow of tourism information within the urban agglomerations was relatively dispersed, while the inflow of tourism information was relatively concentrated. The direction of tourism information flow primarily manifested as a large amount of tourism information flowing from cities within the agglomeration to a few core cities, including provincial capitals. (3) The tourism information flow networks within urban agglomerations mainly exhibited a dual-center axial network or a multi-center radial structure centered on provincial capitals and economically robust cities. Moreover, tourism information flows within urban agglomerations were characterized by short-distance mobility with high fluidity, demonstrating significant regional network clustering effects. (4) The structure of tourism information flow networks within urban agglomerations was greatly influenced by factors such as economic development level, population factors, degree of informatization, tourism and public service level, and psychological distance. [Conclusion] In the context of informatization and digital economy, it is imperative to facilitate the spatial flow and spillover effects of tourism information to drive the upgrading and transformation of regional tourism, thereby achieving the synergistic, complementary, and integrated development of regional tourism.

[Objective] The rapid growth of China’s passenger vehicle ownership has imposed tremendous pressure on resource supply and environmental carrying capacity. Analyzing the development trend of end-of-life resources in the passenger vehicle industry helps reveal the spatiotemporal evolution patterns of resource flows, while providing crucial data support and policy implications for optimizing the resource recycling system and promoting the sustainable development of the new energy vehicle industry. [Methods] Using the Gompertz model and dynamic material flow analysis, this study constructed a predictive framework for passenger vehicle ownership and end-of-life volumes across China’s 4 municipalities and 333 prefecture-level administrative regions. This framework systematically analyzed the spatiotemporal distribution patterns of different end-of-life passenger vehicle resources from 2001 to 2050. [Results] (1) China’s passenger vehicle ownership was projected to reach 450~640 million by 2050, showing significant regional disparities. Provinces such as Henan, Shandong, Hebei, and Guangdong had significantly higher ownership than other regions. (2) By 2050, the annual end-of-life passenger vehicles were estimated to reach 30.94~64.76 million, with a spatial shift observed from coastal cities to inland provincial capitals. Eastern coastal areas, the middle reaches of the Yangtze and Yellow Rivers, and southwestern regions would become concentrated end-of-life zones. (3) As new energy vehicles and hybrid electric vehicles became more prevalent, their end-of-life volumes would gradually exceed that of traditional fuel vehicles, leading to a substantial increase in the end-of-life volume of critical materials such as aluminum, copper, and power batteries. (4) Vehicle lifespan and ownership levels were identified as key driving factors affecting the end-of-life flows of passenger vehicles and automotive materials, exerting significant regulatory effects on the long-term resource metabolism trends. [Conclusion] The research findings provide a scientific basis for capacity planning in the resource recycling industry, formulation of regional differentiated policies, and construction of material recycling systems for new energy vehicles, thereby helping China achieve the “dual carbon” goals and circular economy transition.

[Objective] This study aims to analyze the spatial distribution of the low-altitude economy manufacturing, along with the spatiotemporal correlation patterns and influencing factors of its industry and innovation chains. The findings are expected to provide a theoretical basis and policy support for enhancing the integration of production and innovation in the low-altitude economy. [Methods] Based on the obtained enterprise data related to components and aircraft sectors of the low-altitude economy manufacturing in the Pearl River Delta (PRD) urban agglomeration, this study employed kernel density analysis, co-location quotient analysis, and unordered multinomial logistic regression models to explore the spatial clustering characteristics of low-altitude economy manufacturing, the spatiotemporal correlation patterns between its industry and innovation chains, and their influencing factors. [Results] (1) Both production-oriented and innovation-oriented enterprises in the low-altitude economy manufacturing of the PRD urban agglomeration exhibited a pronounced Guangzhou-Shenzhen dual-core structure. These enterprises were predominantly distributed in various industrial functional zones and central urban areas. (2) The spatiotemporal correlation between production and innovation in the low-altitude economy manufacturing was characterized by production-oriented enterprises leading the spatiotemporal patterns of innovation-oriented enterprises. Meanwhile, the spatiotemporal correlation between industry and innovation chains demonstrated a pattern where component sectors followed the aircraft sectors, while the latter showed a tendency toward independent agglomeration. (3) Different spatiotemporal correlation patterns were influenced by factors such as the levels of industrial functional zones, economic vitality, land prices, distance to airports, cluster types, and enterprise scale, among which national-level industrial functional zones played a particularly prominent role. [Conclusion] The low-altitude economy manufacturing in the PRD urban agglomeration has preliminarily formed a co-agglomeration pattern of production-innovation and industry-innovation chains. However, the overall level of regional co-agglomeration still needs improvement. Building and upgrading the level of industrial functional zones is key to promoting the co-agglomeration among enterprises.

[Objective] Digital infrastructure serves as a sustained driving force for the formation of new-quality productive forces. This study aims to reveal the spatiotemporal evolution, regional disparities, and spatial convergence characteristics of digital infrastructure development in China. This is of great significance for promoting balanced regional development and empowering high-quality growth, and thereby driving the development of new productive forces. [Methods] Using China’s provincial panel data from 2013 to 2022, an indicator evaluation system for digital infrastructure construction and application was established. Methods such as the entropy method, Theil index, convergence models, two-way fixed effects models, and spatial econometrics were employed to conduct an in-depth analysis of the spatiotemporal evolution, regional disparities, and spatial convergence of digital infrastructure. [Results] (1) The level of digital infrastructure development in China exhibited an overall upward trend, but there are spatial differences. It shows a spatial distribution pattern where the eastern region has a higher level, while the western and northeastern regions are relatively lower. (2) The overall differences in the development level of digital infrastructure are gradually narrowing. The differences are shifting from being mainly between regions to being more pronounced within regions. The regional differences within regions show a hierarchical structure of “eastern > western > central > northeastern”. (3) In terms of convergence characteristics, a gradually weakening trend was observed in the convergence of China’s digital infrastructure development level. Both national and regional levels of digital infrastructure development demonstrated spatial conditional convergence, with convergence speeds ranked as follows: the central region was th e fastest, followed by the western and eastern regions, while the northeastern region was the slowest. [Conclusion] Bridging the gaps in digital infrastructure development, reducing regional disparities, and strengthening cross-regional collaboration are key to balanced regional development. This study provides theoretical support and practical guidance for promoting the convergent development of regional digital infrastructure and formulating tailored policies based on regional conditions.

[Objective] With the intensification of climate change, countries worldwide have committed to achieving carbon neutrality to meet the temperature control targets set by the Paris Agreement. The circular economy, as a sustainable development model, is playing an increasingly prominent role in climate change mitigation. However, studies focusing on the coupling of climate change mitigation and circular economy have not yet been systematically summarized. [Methods] Based on the literature indexed in the Web of Science database, this study conducts a bibliometric analysis to summarize the research progress, current status, and hotspots in the coupling of climate change mitigation and the circular economy from 1991 to 2024, thereby providing theoretical support and practical guidance for their integration. [Results] (1) Research on the coupling of climate change mitigation and the circular economy began in 1991 and has gone through three stages: initial exploration, steady development, and rapid growth, with research content expanding from solid waste management and recycling to more industries. (2) Globally, a total of 9520 papers have been published on the coupling of climate change mitigation and circular economy, with Chinese scholars contributing the most. Chinese research institutions serve as pivotal hubs in the international collaboration network, highlighting China’s research strength and international influence in this field. (3) The research on the coupling of climate change mitigation and circular economy focuses on four key areas: climate change, circular economy, waste management, and life cycle assessment. Future research trends are expected to focus on carbon neutrality and zero-carbon goals, renewable energy scenarios, digital and intelligent technologies, and multi-method integration. [Conclusion] In the future, it is necessary to strengthen international cooperation, promote interdisciplinary exchange, and advance technological innovation, while leveraging opportunities presented by digital and intelligent development to further promote synergistic development between climate change mitigation and the circular economy.

[Objective] Scientifically evaluating the spatiotemporal differentiation characteristics of shrinkage and transformation of resource-based cities in China, and understanding their functional relationship and interaction mechanisms are crucial for achieving sustainable development in these cities. [Methods] Based on socioeconomic statistical data and remote sensing monitoring data, an evaluation indicator system was established for shrinkage and transformation of resource-based cities. Using the comprehensive index model, coordinated development model, and geodetector, the spatiotemporal characteristics of shrinkage and transformation from 2000 to 2020 were analyzed, their interactive relationship types were classified, and the key influencing factors were identified. [Results] (1) From 2000 to 2020, both shrinkage and transformation in China’s resource-based cities showed increasing trends, with a spatial clustering patterns. Shrinkage was mainly reflected in the population dimension, while transformation was most evident in the industrial and innovation dimensions. Resource-based cities in Northeast China demonstrated the highest shrinkage degree, while those in the eastern coastal areas showed the highest transformation degree. (2) Most resource-based cities achieved a coordinated state between shrinkage and transformation, but a significant number showed signs of imbalance, predominantly characterized by interactive adaptation types. The effectiveness of urban transformation in alleviating shrinkage remained limited, and spatial variations existed in coordinated development types and interactions between shrinkage and transformation. (3) The interaction between shrinkage and transformation in resource-based cities intensified. Interactions among factors within each system exerted stronger effects than individual factors, with both the depth and breadth of these interactions showing increasing trends. Urban shrinkage restricted transformation through a complex mechanism centered on population outflow and economic growth slowdown, while urban transformation alleviated shrinkage through a reverse mechanism driven primarily by energy-saving and emission-reduction policies. [Conclusion] Over the past 20 years, China’ s resource-based cities have achieved remarkable progress in urban transformation, though its mitigating effects on urban shrinkage remain insufficient. The key approach to achieving sustainable development in resource-based cities lies in promoting comprehensive transformations, establishing differentiated economic and ecological compensation mechanisms, and enhancing energy efficiency and green production levels. This study not only provides an effective framework for analyzing the shrinkage-transformation relationship in resource-based cities, but also offers scientific references for achieving sustainable development in resource-based cities.

[Objective] The return migration of highly educated groups represents a new phenomenon in China’s current population mobility. Investigating its spatial and demographic characteristics helps understand new trends in China’s population migration during the transitional period. [Methods] Based on the dual sticky effects of hometown ties and educational ties on highly educated groups, this study defined return migration of highly educated groups as their relocation to either household registration location or university location. Three types of return migration were identified: Type I, returning to home province after educational migration; Type II, returning to home province after employment migration; Type III, returning to the province of their university after employment migration. Building upon this, this study utilized 2020 recruitment data for primary and secondary school teachers in Wuhan, combined with models for spatial and statistical analyses, to reveal the return migration pathways of highly educated groups targeting Wuhan as their intended destination. Then, the spatial and demographic characteristics of this migration were analyzed. [Results] (1)The return migration of highly educated groups with Wuhan as the destination exhibited a concentrated pattern in southeastern China. It formed a diamond-shaped spatial structure, with the Yangtze River Delta, Pearl River Delta, Beijing, and Chengdu-Chongqing regions as four key nodes, while additional nodal points included Shenyang, Kunming, and Changchun. Notably, the majority of return migrants originated from within this diamond-shaped structure. (2) Distinct regional differences were observed among return migration types. Type I migrants predominantly originated from the northeastern and southwestern parts of China, Type II migrants were more concentrated in eastern China, and Type III migration exhibited localized mobility patterns within proximate regions. (3) Samples characterized by “younger age, county-level birth origin, higher education attainment, elite academic institutions, recent graduates, and employment or study location in higher-tier cities” exhibit a higher probability of return migration. [Conclusion] Compared to international skilled migrants and China’s rural migrant workers, highly educated groups in China are more likely to gain human capital advantages in their hometowns or university locations, which strengthens local utility and fosters return migration through hometown ties and educational ties. Moreover, their return migration largely results not from aspiration failures but rather from a spatial re-selection aimed at maximum benefits, which has positive implications.

[Objective] Resource recycling of end-of-life battery cathode materials has carbon emission reduction potential, but existing studies show significant deviations in emission reduction calculations due to unclear accounting boundaries. This study develops an improved accounting method for carbon emission reduction from the perspective of multiple-life-cycle resource cycling. [Methods] Using virgin material substitution as the baseline scenario, the energy consumption and auxiliary material emissions during resource utilization were incorporated. The method emphasized that recycling only delayed rather than avoided carbon emissions from final disposal, thus excluding final disposal from accounting boundaries. The carbon emission reduction from recycling 1 ton of cathode materials was quantified through four recycling processes for lithium iron phosphate and ternary lithium batteries. [Results] (1) Compared with scenarios of “virgin material substitution combined with incineration disposal” and “virgin material substitution combined with landfill disposal”， the carbon emission reductions from recycling processes decreased by 0.80 t CO₂ eq and 7.96 t CO₂ eq, respectively, when “virgin material substitution” was adopted as the baseline. This indicated that including final disposal (landfill or incineration) in the baseline scenario substantially overestimated carbon emission reduction benefits. (2) Both the slurry acid leaching process for lithium iron phosphate and the acid leaching-extraction process for ternary lithium batteries demonstrated carbon reduction benefits. Notably, the ternary lithium batteries achieved carbon emission reductions 10 times higher than those of lithium iron phosphate due to recoverable high-value metals like nickel and cobalt. (3) The calcination-acid leaching process resulted in a higher carbon footprint for the recycled materials than that of virgin materials owing to the substantial emissions from auxiliary material (e.g., citric acid) production. [Conclusion] In summary, the baseline scenario selected in this accounting method aligns more closely with current production realities domestically and internationally, facilitating the establishment of consistent standards for comparing resource recycling technologies within the industry. Furthermore, through analysis of the calculation results, “high-carbon” processes and the corresponding sensitive factors can be identified to guide process improvement.

[Objective] As a key support for strategic emerging industries, clean energy supply chains play a central role in the global energy transition. In the context of the “dual carbon” goals and energy security demands, it is essential to systematically analyze the development paths and trends of clean energy supply chains, so as to provide decision-making references for enhancing the competitiveness of strategic emerging industries and building a new energy system. [Methods] This study employs bibliometric analysis and knowledge graph methods to construct a theoretical framework for clean energy supply chain research. It systematically reviews the research hotspots, frontier progress, and evolutionary trends in this field from 2005 to 2024, and thoroughly analyzes the key challenges and future trends. [Results] (1) The research shows distinct phases of development. Before 2016, the number of publications remained low with slow growth. After 2016, the field entered a rapid development stage, characterized by a regional pattern dominated by Europe and North America, with emerging Asian economies rapidly catching up. (2) In terms of research hotspots, recent studies have focused on risk optimization strategies, innovations in modeling and technology, and sustainable management of clean energy supply chains. (3) Regional comparative studies have shown significant differences between domestic and international research frontiers. In both cases, the evolution follows three stages: initiation, fluctuation, and rapid development. The research content shows increasing diversity and continuous expansion into new domains. (4) At the practical level, a series of key challenges persist, including uneven resource distribution, bottlenecks in key technologies, and information asymmetry. [Conclusion] Based on the above findings, future research on clean energy supply chains should focus on reconstructing a theoretical framework for supply chains with multi-dimensional integration, conducting in-depth analysis from multifunctional perspectives, revealing interactive feedback mechanisms of complex systems, and optimizing sustainable management pathways in alignment with strategic security objectives.

Resources science is a discipline that studies the formation, evolution, patterns of natural resources, and their interrelationships with human activities, characterized by its comprehensiveness, interdisciplinarity, and problem-oriented nature. As a major strategic emerging industry, the low-altitude economy has experienced rapid development in recent years, yet the understanding of its key foundation-low-altitude resources-needs to be strengthened. The low-altitude era calls for enhanced systematic and innovative research on low-altitude resources within the discipline of resources science. First, this study defines the concept of low-altitude resources and analyzes their four major attributes-natural, social, economic, and strategic. A multidimensional classification system is explored based on spatial, material, energy, and information-related dimensions, and the concept of “low-altitude rights” is introduced. Furthermore, this study constructs the research framework of low-altitude resources, analyzes their research characteristics, and proposes key research priorities and interdisciplinary integration directions. Finally, the future development of resources science in the context of low-altitude resources as the “new resource” and “new space” is envisioned from four aspects: supporting national strategic needs through science and technology, promoting systematic innovation in disciplinary research paradigms, advancing the development of resources science and technology systems, and enhancing global discourse power in resource utilization. This study aims to expand the research framework of resource science, provide technological support for the coordinated and sustainable utilization of low-altitude resources and the high-quality development of the low-altitude economy, aligning the discipline with the demands of the era of profound changes and fostering new academic growth points.

[Objective] Copper, as a critical strategic mineral resource, plays a pivotal role in the low-carbon energy transition of the power sector and the process of carbon neutrality. China is a country with a shortage of copper resources. Scientifically predicting the future demand and scrap generation of copper resources in the power system holds significant strategic importance for ensuring national copper resource security and optimizing resource recycling systems. [Methods] Based on the internationally recognized Integrated Policy Assessment Model (IPAM) under the global warming scenarios of 1.5 °C and 2 °C, as well as China’s “dual carbon” scenario and the dynamic material flow analysis method, this study estimated the in-use stock, demand, theoretical scrap volume, and degree of external dependence of copper in China’s power system from 1950 to 2050. [Results] (1) China’s installed power generation capacity was projected to increase from 1.85 million kW in 1950 to 5.4-6.0 million kW by 2050. The share of renewable energy generation was expected to increase with policy stringency, reaching 80% in the 1.5 °C scenario, 73% in the “dual carbon” scenario, and 67% in the 2 °C scenario by 2050. (2) By 2050, the in-use stock, demand, and theoretical scrap volume of copper in China’s power system were projected to reach 140-160 million tons, 6.5-8.1 million tons, and 4.0-4.8 million tons, respectively, representing an increase of approximately 3 times, 1.5 times, and 10 times compared to the levels in 2022. (3) In the 1.5 °C global warming scenario, China’s power system showed the highest copper demand, stock, and theoretical scrap volume, followed by China’s “dual carbon” scenario. (4) China’s degree of external dependence on copper resources showed a significant downward trend. In the 1.5 °C global warming scenario, it was projected to decline from 70% in 2023 to 48% by 2050, while it was expected to decrease further to 40% in the “dual carbon” scenario. In contrast, in the 2 °C global warming scenario, the dependence was projected to decrease to 38%. [Conclusion] China’s low-carbon power transition will significantly increase copper demand. The utilization of recycled copper can reduce the degree of external dependence, but short-term supply risks remain. It is recommended to strengthen resource exploration, recycling, and supply-demand assessment to ensure copper resource security.

[Objective] Industrial parks serve as critical hubs for zero-waste construction and carbon emission reduction. However, previous studies lacked quantitative methods for evaluating the carbon mitigation benefits of solid waste management in these parks. Developing a quantitative evaluation framework for carbon reduction performance in zero-waste park development carries both theoretical and practical implications for standardizing the accounting of carbon reduction benefits in such parks. [Methods] A framework for the quantitative evaluation of carbon reduction performance in zero-waste industrial parks was developed based on material flow analysis (MFA) and life cycle assessment (LCA). The framework comprised six core steps: determining objectives and scope, establishing waste flow diagrams, selecting disposal technologies, investigating emission levels, identifying carbon reduction performance, and evaluating results with decision support. Additionally, two nested inner loops, measure improvement and emission control, were incorporated to dynamically track synergistic carbon reduction benefits and identify technical pathways for zero-waste park development. [Results] The proposed framework was empirically validated and demonstrated through a case study of an actual industrial park in Beijing E-Town. In 2022, the selected industrial park achieved a carbon reduction of 17000 tons through co-processing of hazardous waste in cement kilns. Additional reductions of 103 000 tons were realized by recycling general industrial sludge, scrap steel plates, and paper packaging or cartons. The accounted waste quantity represented approximately 50% of the total waste generated in the industrial park that year. [Conclusion] The proposed framework accommodates both park-specific and universal characteristics, making it applicable to various parks with diverse industrial structures, production processes, and waste generation characteristics. It upwardly aligns with “zero-waste city” construction and downwardly empowers zero-waste company development, thus facilitating coordinated decision-making for waste-free development and the achievement of the “dual carbon”goals.

[Objective] The unmanned aerial vehicle (UAV) industry is an important pillar of the low-altitude economy. A thorough analysis of the spatial pattern evolution characteristics and driving mechanisms of China’s UAV industry can provide theoretical support and decision-making reference for the development of the low-altitude economy and the optimization of regional industrial layout. [Methods] Based on data from 45070 UAV enterprises across 280 prefecture-level cities in China from 2010 to 2022, kernel density estimation, spatial autocorrelation, and geodetector were employed to analyze the spatial pattern characteristics and influencing factors of the UAV industry in China. [Results] (1) The UAV industry demonstrated significant spatial agglomeration in regions such as the Pearl River Delta, Yangtze River Delta, and Beijing-Tianjin-Hebei region, and its spatial pattern evolved from scattered point distribution to multi-core agglomeration. (2) Innovation-driven development, industrial linkages, and application scenarios were the core factors shaping the spatial pattern of the UAV industry. (3) The synergistic effects between innovation output, human capital, and technological services were significant, while factors such as economic foundation, institutional support, and industrial agglomeration exhibited differentiated interactive effects. [Conclusion] The spatial evolution of China’s UAV industry demonstrates innovation-centered characteristics. In the future, efforts should focus on improving the efficiency of innovation resource allocation, enhancing industrial collaboration mechanisms, optimizing spatial layout and application ecosystems to promote the upgrading of industrial agglomeration and coordinated regional development.

[Objective] This study aims to systematically identify the core institutional barriers hindering the development of China’s agricultural low-altitude economy, reveal the key constraints during its transition from experimental technologies to systematic development, and draw on advanced international experience, thereby providing theoretical support and practical reference for constructing the policy pathways for China’s agricultural modernization. [Methods] Through intrinsic logic analysis and a review of international experiences, this study conducts a core challenge analysis focusing on technological application and institutional environment in agricultural low-altitude economy. The EU, Israel, Japan, the U.S., and the Netherlands are selected as representative economies or countries. Their policy response pathways are analyzed in airspace management, technological adaptation, service systems, talent support, and data platforms. Institutional experiences that can serve as references for China’s agricultural modernization are subsequently yielded. [Results] Factors including the restructuring of precision production systems, enhancement of resource utilization efficiency, co-evolution of technology and institutions, and transformation of sustainable development paradigm have jointly driven the expansion of application boundaries of the agricultural low-altitude economy and the multidimensional advancement of agricultural modernization. Meanwhile, structural contradictions in technological application and systemic barriers in the institutional environment constrain the development potential of China’s agricultural low-altitude economy. [Conclusion] The high-quality development of agricultural low-altitude economy requires overcoming practical bottlenecks in technological advancement and constructing an adaptive institutional framework and governance system. Based on China’s actual conditions, efforts should focus on two dimensions: standardizing the technology system and optimizing institutional framework design, This will fully harness the potential of the low-altitude economy in the agricultural sector and stimulate innovation for agricultural modernization.

[Objective] Lithium resources are regarded as the “lifeline” of the energy transition, yet their supply faces significant geopolitical risks. In this context, it is of great significance to clarify the impact of geopolitical risk on the resilience of the lithium resource trade network to ensure the security of lithium resource supply. [Methods] Based on trade data for lithium hydroxide and lithium carbonate from 22 countries (regions) from 2002 to 2022, this study explored the impact of geopolitical risks on the resilience of lithium resource trade network using a complex network method and a panel regression model. [Results] (1) During the sample period, the resilience of the lithium resource trade network showed a fluctuating upward trend, with a particularly significant increase after 2015. (2) Geopolitical risks had a significant negative impact on the resilience of lithium resource trade network, with the impact being more pronounced in core countries and regions of the network and in high-risk countries and regions. (3) Geopolitical risks negatively affected the resilience of lithium resource trade network by hindering trade cooperation and reducing foreign direct investment. [Conclusion] To mitigate the negative impact of geopolitical risks on lithium resource trade, it is necessary to establish a comprehensive early warning mechanism for emergency risks, promote the implementation of diversified import substitution strategies for lithium resources, and enhance the multi-layered global trade system. In addition, cooperation and risk management between major lithium-producing areas and neighboring countries (regions) should be strengthened.

[Objective] Under the “dual carbon” goals, China faces critical challenges from resource constraints and emerging solid waste disposal problems caused by large-scale renewable energy transition. Thus, predicting the volume of the photovoltaic (PV) solid waste and the recycling potential of associated metals is crucial for the sustainable development in the energy-resource-environment nexus. [Methods] Weibull distribution and scenario analysis methods were integrated to predict the decommissioning volume of the PV modules from power system transition under China’s carbon neutrality goals (2025-2060). Additionally, the scrap and recycling volumes of seven associated metals, such as silver and tellurium, were quantified under different decommissioning modes and technological development scenarios. [Results] (1) From 2025 to 2060, under the early decommissioning mode, China’s cumulative decommissioned and newly installed PV capacities will be 1144 GW and 7591 GW, respectively, exceeding the conventional decommissioning mode by 46% and 5%, respectively. (2) Under different PV market development scenarios, the cumulative scrap volume of associated metals could increase by 9% to 54% compared with the conventional mode. (3) In the conservative scenario, the recycling volumes of all seven associated metals would exceed the demand for PV power generation before 2060. In both moderate and progressive technological scenarios, the recycling volume of silver would continue to exceed its demand. However, even with recycling rates reaching the highest levels by 2030, the recycling volumes of tellurium, cadmium, gallium, selenium, and indium could only meet 18%, 44%, 23%, 14%, and 9% of their respective demands. [Conclusion] Enhancing the operational stability of PV modules, establishing a recycling system for PV solid waste, and maintaining the dominant position of crystalline silicon in PV market will contribute to the security of critical mineral resources for power system transition under China’s “dual carbon” goals.

[Objective] Promoting low-carbon transformation of grain production is a key measure to ensure food security. Exploring the impact of new quality agricultural productive forces on carbon emissions in grain production can help to expand new avenues for ensuring the sustainable development of the grain system. [Methods] Based on the provincial panel data of China from 2011 to 2022, this study used the fixed effects model, mediation effect model, and threshold effect model to explore the impact of new quality agricultural productive forces on carbon emissions from grain production and its mechanism. [Results] (1) The new quality agricultural productive forces in China shows a continuous upward trend, and the overall regional differences are characterized by the main grain sales areas>main grain production areas>balanced production and sales areas. (2) There was a significant inhibitory effect of new quality agricultural productive forces on carbon emissions from grain production. (3) Mechanism analysis revealed that new quality agricultural productive forces mainly suppresses carbon emissions from grain production by expanding the scale of farmers’ operations. (4) Heterogeneity analysis showed that all three dimensions of new quality agricultural productive forces can reduce carbon emissions from grain production, and the carbon reduction effect was high for new agricultural workforce, followed by new agricultural means of production, and low for new agricultural objects of work; In terms of grain production functional areas and geographical locations, the carbon reduction effect of new quality agricultural productive forces mainly occurred in the main grain producing areas, production and sales balanced areas, and northern regions. (5) There was a single threshold in the process of new quality agricultural productive forces affecting carbon emissions from grain production. When the new quality agricultural productive forces exceeded the threshold value of 0.144, its inhibitory effect on carbon emissions in grain production is stronger than before the threshold. [Conclusion] The development of new quality agricultural productive forces helps to replace small-scale farmers with large-scale households, thereby reducing carbon emissions from grain production. We should actively cultivate new types of agricultural management entities, fully utilize intelligent green new technologies and modern agricultural machinery and equipment, develop moderate scale operations, and achieve organic integration with emerging industries related to agriculture in the future, so as to fully tap into the carbon reduction potential of new quality agricultural productive forces.

[Objective] In the context of the increasingly urgent need for green and low-carbon transition of economy and society, exploring the impact and mechanisms of artificial intelligence (AI) development on inclusive green growth has become a crucial research priority. [Methods] Using panel data of prefecture-level cities in China from 2010 to 2021, this study measured the levels of inclusive green growth. Building upon this, methods such as the mediating effect model and panel threshold model were employed to empirically examine the impact of AI on urban inclusive green growth and its underlying mechanisms. [Results] The study found that: (1) current AI development significantly promoted urban inclusive green growth, but exhibited a typical inverted U-shaped relationship. Specifically, as AI levels increased, its impact on urban inclusive green growth first increased and then decreased. The current AI development level (0.003) was substantially below the theoretical optimal threshold (0.441). This conclusion remained valid after using Bartik instrumental variables and other robustness tests. (2) In regions with weak digital infrastructure, non-resource-based cities, and peripheral cities, the empowering effect of AI on inclusive green growth was more pronounced. (3) AI indirectly promoted urban inclusive green growth mainly through three channels: optimizing industrial structure, driving technological innovation, and accumulating human capital. (4) Local government competition could dynamically strengthen the empowering effect of AI on urban inclusive green growth. Among them, environmental competition showed a significant positive U-shaped strengthening mechanism, and its coordination with economic competition could better unleash the potential of AI for inclusive green growth. [Conclusion] It is necessary to diversify AI’s transmission channels to promote urban inclusive green growth, formulate differentiated support policies for weak areas, and properly guide local competition, so as to accelerate the release of growth dividends.