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Background: The Yangtze River Economic Belt, as a core economic region in China, is facing the dual challenges of an aging population and growing healthcare demand, and the balanced development and optimal allocation of nursing human resources is crucial to the region's healthcare system. An in-depth study of the regional differences and convergence of nursing human resources in the region will provide a key basis for policy makers to achieve equity and efficiency in healthcare services and meet the growing demand for healthcare. Aim: To analyze the regional differences and convergence characteristics of nursing human resource levels in the Yangtze River Economic Belt, and to provide scientific references for optimizing regional nursing human resource allocation. Methods: Based on the panel data of 107 cities in the Yangtze River Economic Belt from 2010 to 2020, the regional differences and their sources were analyzed by using Dagum's Gini coefficient, and the convergence characteristics were examined by the coefficient of variation and spatial convergence model. Results: The average value of the number of nursing human resources in the Yangtze River Economic Belt is 2,132,300 people, with obvious regional differences, and the hypervariable density difference (53.01%) is the main source of the regional differences; there are obvious trends of σ-convergence and conditional β-convergence of the level of nursing human resources in the overall and the three major regions of the upstream, midstream, and downstream, and different factors have different moderating effects on the speed of spatial convergence in the other areas. Conclusion: The implementation of precise policies for nursing human resources in different regions of the Yangtze River Economic Belt steadily reduces the regional differences between the upper, middle, and lower reaches and enhances the spatial linkage between regions of nursing human resources to improve the quality of nursing human resources. [ABSTRACT FROM AUTHOR]

The possibility and the prospect of cationic/anionic ("catanionic") surfactant mixtures based on sulfonate Gemini surfactant (SGS) and bisquaternary ammonium salt (BQAS) in the field of enhanced oil recovery was investigated. The critical micelle concentration (CMC) of SGS/BQAS surfactant mixtures was 5.0 × 10−6 mol/L, 1–2 orders of magnitude lower than neat BQAS or SGS. A solution of either neat SGS or BQAS, could not reach an ultra‐low interfacial tension (IFT); but 1:1 mol/mol mixtures of SGS/BQAS reduced the IFT to 1.0 × 10−3 mN/m at 100 mg/L. For the studied surfactant concentrations, all mixtures exhibited the lowest IFT when the molar fraction of SGS among the surfactant equaled 0.5, indicating optimal conditions for interfacial activity. The IFT between the 1:1 mol/mol SGS/BQAS mixtures and crude oil decreased and then increased with the NaCl and CaCl2 concentrations. When the total surfactant concentration was above 50 mg/L, the IFT of SGS/BQAS mixtures was below 0.01 mN/m at the studied NaCl concentrations. Adding inorganic salt reduced the charges of hydrophilic head groups, thereby making the interfacial arrangement more compact. At the NaCl concentration was above 40,000 mg/L, surfactant molecules moved from the liquid–liquid interface to the oil phase, thus resulting in low interfacial activity. In addition, inorganic salts decreased the attractive interactions of the SGS/BQAS micelles that form in water, decreasing the apparent hydrodynamic radius (DH, app) of surfactant aggregates. When the total concentration of surfactants was above 50 mg/L, the IFT between the SGS/BQAS mixtures and crude oil decreased first and then increased with time. At different surfactant concentrations, the IFT of the SGS/BQAS mixtures attained the lowest values at different times. A high surfactant concentration helped surfactant molecules diffuse from the water phase to the interfacial layer, rapidly reducing the IFT. In conclusion, the cationic‐anionic Gemini surfactant mixtures exhibit superior interfacial activity, which may promote the application of Gemini surfactant. [ABSTRACT FROM AUTHOR]

Accurately identifying the matching relationships between territorial space evolution and the resources and environment carrying capacity will directly guide the sustainable use of territorial space. Based on the evaluation of the territorial space dynamics of the lower Yellow River, this paper evaluates the suitability of territorial space development by focusing on ecological protection, agricultural development, and urban construction. Specifically, the resources and environment carrying capacity is estimated by identifying and mediating potential conflicts in the development of territorial space. The matching relationship between the evolution of territorial space and the resources and environment carrying capacity is identified using the matching degree model. The results demonstrated that: (1) Between 2000 and 2020, the agricultural space of the lower Yellow River was relatively stable, while the ecological space was generally shrinking, and the urban space continued to increase; (2) The characteristics of suitability for the agricultural development and urban construction of the lower Yellow River are characterized by landform and land-sea differentiation. The carrying scale of resources and the environment is based on agricultural space and is increasing yearly, followed by ecological space, which is gradually decreasing, and urban space, which first increased and then decreased; (3) Between 2000 and 2020, the matching index of the ecological and agricultural space evolution and the resource and environmental carrying capacity in the lower Yellow River exhibited a downward trend, while the regional difference increased. Furthermore, the matching index of urban space and the resources and environment carrying capacity indicated an upward trend, while the regional difference decreased. [ABSTRACT FROM AUTHOR]