Search Results (222)

Against the backdrop of rapid modernization and tightening agricultural resource constraints, coordinating urbanization and grain production is a key challenge for China. Using panel data from 30 Chinese provinces from 2004 to 2023, this study applies the coupling coordination degree (CCD) model and a panel vector autoregression model to examine the spatiotemporal coupling characteristics and interaction mechanisms among new-type urbanization (NTU), cultivated land use efficiency (CLUE), and food security (FS). The results show that these three systems have gradually evolved toward coordinated development, with major grain-producing regions consistently leading and entering a moderate coordination stage earlier than other regions. Spatially, CCD exhibits significant positive spatial autocorrelation, characterized by stable “High–High” agglomeration in Northeast China and “Low–Low” agglomeration in southern provinces. Dynamic analysis indicates that system fluctuations are mainly driven by internal inertia, while inter-system interactions are also significant; NTU promotes CLUE, and CLUE and FS exhibit bidirectional causality with complex feedback effects. This study argues for promoting urban–rural factor mobility, advancing green and technology-enabled land use, implementing region-specific development strategies, and establishing a “human–land–grain” early-warning mechanism to safeguard food security during urban expansion. Full article

The successful attainment of the Sustainable Development Goals (SDGs) necessitates robust monitoring frameworks capable of tracking progress toward tangible outcomes while capturing dynamic sustainability trajectories. However, existing SDG evaluation methods suffer from three critical limitations: (1) misalignment between global targets and national priorities, which undermines contextual relevance; (2) fragmented assessments that neglect holistic integration of social, economic, and ecological dimensions, thereby obscuring systemic interdependencies; and (3) insufficient longitudinal analysis, which restricts insights into temporal patterns of sustainable development and hinders adaptive policymaking. To address these gaps, we employed China’s 31 provinces as a case study and constructed an SDG indicator framework comprising 178 metrics—harmonizing global SDG benchmarks with China’s national development priorities. Using official statistics and open-source data spanning 2006–2021, we evaluate longitudinal SDG scores for all 17 goals (SDGs 1–17). Additionally, we developed a composite SDG index that considers the coupling coordination degree of the social–economic–ecological system and evaluated the index value under different economic region settings. Finally, we developed a two-threshold model to analyze the dynamic evolution of SDG conditions, incorporating temporal sustainability (long-term development resilience) and action urgency (short-term policy intervention needs) as dual evaluation dimensions. This model was applied to conduct a longitudinal analysis (2006–2021) across all 31 Chinese provinces, enabling a granular assessment of regional SDG trajectories while capturing both systemic trends and acute challenges over time. The results indicate that China’s social SDG performance improved substantially over the 2006–2021 period, achieving a cumulative increase of 126.53%, whereas progress in ecological SDGs was comparatively modest, with a cumulative growth of only 23.93%. Over the same period, the average composite SDG score across China’s 31 provinces increased markedly from 0.502 to 0.714, reflecting a strengthened systemic alignment between regional development trajectories and national sustainability objectives. Further analysis shows that all provinces attained a status of “temporal sustainability with low action urgency” throughout the study period, highlighting China’s overall progress in sustainable development. Nevertheless, pronounced regional disparities persist: eastern provinces developed earlier and have consistently maintained leading positions; central and northeastern regions exhibit broadly comparable development levels; and western regions, despite severe early-stage lagging, have demonstrated accelerated growth in later years. Our study holds substantial significance by integrating multi-dimensional indicators—spanning ecological, economic, and social dimensions—to deliver a holistic, longitudinal perspective on sustainable development. Full article

The natural gas sector, as a pivotal transition fuel, is fundamentally constrained by the “Energy Trilemma”—the intertwined and often competing goals of energy security, affordability, and sustainability. Current research predominantly focuses on the demand side, leaving a significant gap in understanding the synergistic dynamics within production regions, which are critical to resolving this trilemma at its source. To address this gap, this study constructs a “Safety–Economy–Green” (S-E-G) evaluation framework aligned with the trilemma’s dimensions. Utilizing panel data (2011–2021) from four major Chinese natural gas production regions (Sichuan, Chongqing, Shaanxi, and Shanxi). By integrating the Entropy Weight Method, a Coupling Coordination Model, and Kernel Density Estimation, it delineates the system’s synergistic dynamics from both temporal and regional perspectives. The key findings are as follows: (1) Significant disparities and polarization are observed in the S and G dimensions, while the E dimension shows a narrowing gap, with its peak height increasing by 177.8% and bandwidth shrinking by 64.2%. G has emerged as a constraint on overall system coupling coordination. The persistently high coupling degree—rising from 0.87 in 2011 to 0.97 in 2021 while consistently exceeding the coordination degree, which increased from 0.45 to 0.62—underscores the continued need for improvement in synergistic development. (2) The coupling coordination degree of the S-E-G system underwent a three-stage evolution: rapid improvement (2011–2013, from 0.36 to 0.58 at 7.3% annually), fluctuating adjustment (2014–2017, between 0.58 and 0.66), and finally high-level stability (2018–2021, stabilizing at 0.76–0.80). (3) Obvious regional differentiation exists: Sichuan achieved a moderate level of 0.76 by 2021, Shaanxi maintained primary coupling coordination (0.6–0.7), while Chongqing and Shanxi remained marginal, fluctuating between 0.4 and 0.6. Enhancing subsystem coordination and implementing differentiated pathways are therefore essential for these regions’ sustainable development. The study suggests promoting the sustainable development of natural gas production regions by enhancing subsystem coordination and exploring differentiated pathways, thereby providing practical guidance for the energy transition of resource-based regions. Full article

Against the backdrop of rapid urbanization, megacities have become crucial drivers of development. As the country with the largest number of megacities (seven in total), China is confronted with significant challenges such as population–resource–environment conflicts, which render high-quality development an imperative pursuit. This study employs a system dynamics approach to assess high-quality development in China’s megacities. It analyzes interactions among economic growth, technological innovation, environmental quality, and livelihood security under policy regulation, clarifying their evolutionary mechanisms and constructing a model to project the high-quality development index (HQDI) and coupling coordination degree (CCD) among subsystems. Findings reveal an upward trend in both HQDI and CCD across the seven megacities, with notable stratification. Beijing, Shanghai, and Shenzhen form the top echelon, leveraging financial and technological resources, driven by science and green development. Guangzhou and Chongqing constitute the second tier, supported by regional integration and industrial clusters, while Chengdu and Tianjin form the third echelon via regional strategic transformations. In coordinated development, Shanghai, Beijing, Shenzhen, and Guangzhou lead with multi-link synergy, whereas Chengdu, Chongqing, and Tianjin advance industry–ecology–livelihood coordination through regional strategies. This study offers insights for overcoming development bottlenecks, optimizing policies, and enhancing urban governance to foster a coordinated, high-quality development pattern. Full article

With increasing emphasis on ecological conservation and food security, cultivated land issues have become more prominent. This study focuses on Jilin Province and uses nine prefecture-level administrative units and prefectures as the basic analytical units. Using continuous data for 2000–2023, this study analyzes the spatiotemporal evolution of cultivated land use efficiency (CLUE). By 2023, most regions had achieved ecological safety (ES), examined through their coupling and coordination. The Super-Efficiency SBM-DEA model and the Malmquist–Luenberger (ML) index were used to evaluate the static and dynamic changes in CLUE. A DPSIR–PLS-SEM integrated framework was applied to identify causal mechanisms influencing ES, while the TOPSIS method was employed to assess overall evolutionary trends. In addition, the coupling coordination degree (CCD) model combined with kernel density estimation (KDE) was used to characterize the interaction between CLUE and ES and their spatial evolution. Results indicated the following: (1) From 2000 to 2023, overall CLUE in Jilin Province showed an upward trend with fluctuations, while regional disparities narrowed and spatial distribution became more balanced. (2) The composite ES index increased from 0.3009 to 0.7900, accompanied by a marked expansion of areas classified as secure. (3) The CCD improved from a basic level to a high-quality coordination level, indicating enhanced synergistic development. Higher coordination was observed in central and eastern regions, whereas western and peripheral areas lagged. This study integrates multi-dimensional modeling approaches to systematically assess the coupled dynamics on cultivated land use efficiency and ecological safety, providing insights for land management and policy formulation. Full article

As the digital economy increasingly integrates with the real economy, the goal of high-quality economic development in China has become increasingly clear. Promoting high-quality regional economic development through the integration of the digital and real economies holds significant practical importance for achieving Chinese modernization. This study selects panel data from 2013 to 2023 for 31 provinces, autonomous regions, and municipalities directly under the central government in China. It employs the entropy method to measure the development levels of both the digital and real economies in each province. It uses a coupling coordination degree model to gauge their level of integration. By constructing bidirectional fixed-effects models, mediating effect models, and spatial econometric models, this study explores the impact of Digital–real Integration (DRI) on regional High-Quality Development (HQD). The findings reveal that DRI promotes high-quality regional economic development, with a 1% increase in DRI leading to a 4.810% increase in high-quality regional economic development. Meanwhile, this effect exhibits significant regional disparities. During this process, industrial structure upgrading and scientific and technological innovation serve as mediating factors, with coefficients of 1.249 and 10.562, respectively, for every 1% increase in DRI. Moreover, DRI exhibits significant spatial spillover effects, benefiting neighboring regions. Based on these findings, the paper proposes targeted recommendations, including strengthening digital infrastructure to lay a solid foundation for integrated development, implementing an innovation-driven strategy to master core technologies, optimizing production factor allocation to amplify DRI’s driving force, breaking regional economic barriers, and adopting dynamic, differentiated development strategies tailored to local conditions. These measures aim to fully harness DRI’s potential in advancing high-quality regional economic growth, offering empirical insights for coordinated regional development. Full article

The shipping service industry plays a pivotal role in enhancing port competitiveness and fostering urban economic growth, yet limited studies systematically integrate its spatial temporal dynamics with the processes driving port–city synergy. This study constructs a three-dimensional analytical framework encompassing port operations, urban economic development, and shipping service industry agglomeration. Using data from 13 port cities in Jiangsu Province (2015–2023), we apply the entropy weight method, coupling coordination degree model, relative development model, and panel Tobit regression to evaluate interaction intensity, coordination patterns, and influencing factors. Results reveal a clear spatial gradient in coupling coordination, higher in southern Jiangsu and lower in the north, driven by disparities in economic foundations, port capacities, and service industry structures. In most cities, port operations and urban economies lag behind shipping service industry agglomeration, reflecting the predominance of low- and mid-end services. Port construction level, cargo and container throughput, economic development, openness, fixed asset investment, and population density significantly promote coordination, whereas R&D capacity shows no significant effect. The findings advance understanding of port–city service interlinkages and provide targeted policy recommendations for differentiated regional development, infrastructure enhancement, and upgrading toward high-end shipping services, with implications for maritime regions worldwide. Full article

Evaluating the relationship between dynamic carbon emission intensity (CEI) and high-quality economic development (HQED) provides crucial insights for advancing national strategies focused on ecological preservation and sustainable high-quality development. This study employed an integrated analytical framework that combines the entropy-weight TOPSIS model, the coupling coordination degree (CCD) model, the spatial autocorrelation, and a two-way fixed effects model to examine the spatiotemporal patterns and influencing factors of carbon emissions in the Yangtze River Basin from 2010 to 2022. The results indicated that: (1) Temporal analysis revealed a consistent annual decline in CEI levels, coupled with steady improvements in HQED. The coordination between these two systems was reflected in the estimated CCD, and it showed an upward trend, with the lower reaches experiencing the most rapid progress in coordination. (2) Spatial analysis revealed a polycentric development pattern, with Shanghai serving as the central core, and other metropolises such as Nanjing and Hangzhou acting as secondary cores. The high–high agglomeration area has been progressively expanding each year. (3) Analysis of influencing factors revealed that their impacts diminished in the following order: human capital, economic development, urbanization, green innovation, government support, industrial structure, and openness. Each of these influencing factors demonstrated distinct spatiotemporal heterogeneity, varying in their impact across different regions and time periods. The study finally provided recommendations, emphasizing the need for coordinated development strategies in the YREB, taking regional dynamics into account, and promoting green economic transformations while ensuring ecological and environmental sustainability. Full article

The Yellow River Basin serves as a critical ecological barrier and economic corridor in China, playing a pivotal role in national ecological security and sustainable development. This study develops a comprehensive evaluation framework grounded in the Water–Energy–Food–Ecosystem (WEFE) nexus, employing 25 indicators across nine provinces and autonomous regions over the period 2000–2023. Utilizing a multi-method approach—including the entropy weight method, coupling coordination degree model, center of gravity migration analysis, principal component analysis, and obstacle factor diagnosis—the research investigates the coordinated development and dynamic interactions among the WEFE subsystems. Key findings include: (1) the calculated weights of the water, energy, food, and ecological subsystems were 0.3126, 0.1957, 0.1692, and 0.3225, respectively, indicating that ecological and water subsystems exert the greatest influence; (2) distinct growth patterns among subsystems, with the energy subsystem exhibiting the fastest growth rate (212%) and the water subsystem the slowest (4%); (3) a steady improvement in the overall coordination degree of the WEFE system, rising from 0.417 in 2000 to 0.583 in 2023—a 39.8% increase—with Henan (0.739) and Inner Mongolia (0.715) achieving the highest coordination levels in 2023, while Qinghai (0.434) and Ningxia (0.417) remained near imbalance thresholds; (4) complex spatial dynamics reflected by cumulative center of gravity migration distances of 678.2 km (water), 204.9 km (energy), 143.3 km (food), and 310.9 km (ecology) over the study period; and (5) identification of per capita water resources as the principal limiting factor to coordinated WEFE development, with an obstacle degree of 0.1205 in 2023, underscoring persistent water scarcity challenges. This integrated framework advances WEFE nexus analysis and provides robust, evidence-based insights to inform regional policy and resource management strategies. Full article

China’s ecological civilization construction and the “dual-carbon” strategy highlight the urgent need for coordinated governance of pollution and carbon reduction. Whether data elements and artificial intelligence integration (DEAII) can serve as a new pathway to achieve this goal remains to be explored. This study investigates the dynamic effects of DEAII on pollution and carbon reduction using panel data from 275 prefecture-level cities in China during 2009–2021. An evaluation index system and a modified coupled coordination degree model are developed to measure DEAII, while an ordinary least squares (OLS) fixed effects model is applied to assess its impacts. The results show stage-specific effects of DEAII, including the phenomenon of “pollution reduction but carbon increase”. Mechanism analysis indicates that improvements in green energy technology efficiency (GETE) and optimization of urban spatial structure are the main channels for achieving synergy. Heterogeneity analysis reveals that although government attention to environmental protection strengthens pollution control, it has limited effects on short-term carbon reduction. Moreover, the carbon reduction benefits of green energy transition pilots exhibit a time lag, and the “digital intelligence divide” generates negative spatial spillovers. These findings provide new evidence for the dilemma of “environmental protection without low-carbon benefits” and suggest policy directions for enhancing the coordinated governance of pollution and carbon reduction. Full article

Identifying the key drivers behind the spatiotemporal dynamics of ecosystem service functions is essential for clarifying how ecosystems respond to environmental changes. Such insights deepen our understanding of the evolution of complex ecological processes and service functions, and provide critical references for ecological governance, policy-making, and the pursuit of high-quality development pathways. In this study, the Remote Sensing Ecological Index (RSEI) was first constructed for the upstream basin of the Danjiangkou Reservoir using satellite imagery (2015 and 2024). We then employed the InVEST model to quantify six ecosystem service functions and their corresponding services: water purification (total nitrogen and total phosphorus), soil retention (soil erosion), water yield, carbon storage, and habitat provision (habitat quality). Finally, this study analyzes the driving mechanisms as well as the coupling coordination degree between the RSEI and six ecosystem service functions. From 2015 to 2024, the area classified as “excellent” in RSEI significantly expanded from 263.34 km² (3.22%) to 2566.21 km² (31.38%), reflecting a substantial enhancement in ecological quality throughout the upstream basin. There is no serious imbalance in the coupling and coordination relationship between RSEI and the value of various ecosystem service functions. Although improvements in ecosystem quality generally enhanced overall ecosystem service functions, competition among certain services was still evident in localized areas. Future ecological management should, therefore, prioritize not only the protection of ecosystem quality but also the scientific allocation of service supply and demand, the optimization of human–land relationships, and the promotion of a virtuous ecosystem cycle. Full article

Rural revitalization relies on both industrial upgrading and cultural reinvigoration. Tea-culture–tourism integration has been regarded as a potentially effective route for advancing rural revitalization, yet its interactive relationship and dynamic evolution remain insufficiently understood. Based on provincial-level panel data from 18 major tea-producing provinces in China between 2013 and 2022, this study constructs two comprehensive evaluation index systems for tea–culture–tourism integration and rural revitalization. It employs the entropy weight method, the coupling coordination degree model, the Dagum Gini coefficient decomposition, and spatial econometric models to measure their coupling coordination degree and analyze its spatiotemporal pattern, regional disparities, and driving factors. The main findings are as follows: (1) Both tea–culture–tourism integration and rural revitalization exhibited upward trends, with the latter being consistently higher. (2) The coupling coordination degree transitioned from dissonance to coordination, spatially forming a gradient progression pattern of “coastal-river-inland”. (3) Regional disparities were primarily dominated by transvariation density and inter-regional differences. (4) Results of spatial econometric models indicated that fiscal conditions exerted a significant positive direct effect, while urban–rural social development, employment structure, and human capital generated significant positive direct and indirect effects. Full article

The coordinated scheduling of diesel generators, photovoltaic (PV) systems, and energy storage systems (ESS) is essential for improving the reliability and resilience of islanded microgrids in remote and mission-critical applications. This review systematically analyzes diesel–PV–ESSs from an “energy symbiosis” perspective, emphasizing the complementary roles of diesel power security, PV’s clean generation, and ESS’s spatiotemporal energy-shifting capability. A technology–time–performance framework is developed by screening advances over the past decade, revealing that coordinated operation can reduce the Levelized Cost of Energy (LCOE) by 12–18%, maintain voltage deviations within 5% under 30% PV fluctuations, and achieve nonlinear resilience gains. For example, when ESS compensates 120% of diesel start-up delay, the maximum disturbance tolerance time increases by 40%. To quantitatively assess symbiosis–resilience coupling, a dual-indicator framework is proposed, integrating the dynamic coordination degree (ζ ≥ 0.7) and the energy complementarity index (ECI > 0.75), supported by ten representative global cases (2010–2024). Advanced methods such as hybrid inertia emulation (200 ms response) and adaptive weight scheduling enhance the minimum time to sustain (MTTS) by over 30% and improve fault recovery rates to 94%. Key gaps are identified in dynamic weight allocation and topology-specific resilience design. To address them, this review introduces a “symbiosis–resilience threshold” co-design paradigm and derives a ζ–resilience coupling equation to guide optimal capacity ratios. Engineering validation confirms a 30% reduction in development cycles and an 8–12% decrease in lifecycle costs. Overall, this review bridges theoretical methodology and engineering practice, providing a roadmap for advancing high-renewable-penetration islanded microgrids. Full article

The cooling system is a core component for a vehicle’s powertrains to operate smoothly and maintain a satisfying noise, vibration, and harshness (NVH) performance. However, advances in new energy vehicles bring with them complex requirements for the cooling fan design due to new issues such as increased heat load, dynamic variations, and high-speed vibrations, which demand the optimization of fan dynamics over a wide range of parameters. In this paper, by thoroughly checking the effect of rigid–flexible coupling and the geometrically complex elastic frame of the fan, we propose a combined modeling approach to reduce the computational time of broad-range parameter variation analysis and examine the vibration problem in the cooling fans under various external excitations. First, the complicated frame of the fan is simplified through virtual prototyping based on an experiment. Then, modal transition is applied, reducing the complex kinetic expression, and a time-invariant system model is derived with multi-blade coordinate transformation. Stability and bifurcation analysis are performed regarding different excitation couplings from the rotor, powertrain, and road. The results of the simulation and experiment illustrate that the proposed methodology achieves a substantial reduction in computational time, and all degrees of freedom (DOFs) are divided into two groups including symmetrical and asymmetrical types. The results also imply the great potential for the optimization and control of the high-speed fan’s vibration for new energy cars. Full article

Although the role of digital infrastructure as an engine for the sustainable development of public services has been widely investigated, systematic and dynamic analysis of the coupling and coordination mechanisms between digital infrastructure and public employment service efficiency is lacking. On the basis of Chinese provincial panel data from 2012 to 2023, the coupling coordination degree model, Dagum’s Gini coefficient, Markov chain, and Tobit model are used to measure the coupling coordination degree of digital infrastructure and public employment service efficiency, analyze its spatial pattern, and explore its influencing factors. The results of this study reveal that (1) The coupled and coordinated development trend of digital infrastructure and public employment service efficiency has improved from “mild imbalance recession” to “near imbalance recession”. (2) The spatial difference in the coupling coordination degree is characterized by slow expansion but overall stabilization, and the spatial transfer state remains relatively stable. (3) Economic development, industrial structure, trade openness, and technological development increase the coupling coordination degree, whereas urbanization, the urban–rural income gap, and government intervention hinder it. This study not only expands the theoretical boundaries of digital governance research and overcomes the theoretical limitations of traditional public employment service research but also has substantial practical importance for promoting social equity, inclusive growth, and economic sustainability. Full article