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Studying the spatial characteristics of China's ageing and its influencing factors is of great practical significance because China has the largest elderly population in the world. Using 2000 and 2010 census data, this study explores the degree, pace, and pattern of population ageing and its driving mechanism using exploratory spatial data analysis and the geographically weighed regression model. Between 2000 and 2010, population ageing increased rapidly countrywide; yet, spatial differences between eastern and western China narrowed. The degree of provincial population ageing and its spatiality were determined by natural population growth, migration, and local economic development. Life expectancy and mortality were the primary long-term factors, and GDP per capita was the prime contributor in the early days of economic development; the migration rate was the dominant influence after 2010. China's overall spatial differentiation of population ageing shifted from a north–south to an east–west division. [ABSTRACT FROM AUTHOR]

The imbalance between supply and demand of elderly care resources in the Yangtze River Delta is increasing. By the older adult agglomeration, spatial cluster analysis, hotspot analysis, and coupling coordination model, this study explores the spatial coupling relationship between older adults and elderly care resources in the Yangtze River Delta in 2020 from the perspective of a supply-and-demand balance. The results demonstrate that: (1) population aging is mainly in the moderate aging stage, followed by the primary aging stage; (2) there are significant spatial differences in elderly care resources on the urban scale in the Yangtze River Delta; and (3) elderly care resources and the older adults in the Yangtze River Delta are mostly highly coupled. However, Nantong, with the highest degree of aging, has a serious mismatch in life service resources and ecological environment resources. The social security resources and medical resources of provincial capital cities with low aging are mismatched. Medical and health resources in underdeveloped areas are seriously mismatched. The social security resources are barely matched in Shanghai. A path for optimizing the spatial allocation of elderly care resources is proposed. This research offers a decision-making reference for coordinating elderly care resources distribution. [ABSTRACT FROM AUTHOR]

In this study, agricultural waste luffa vines (LVs) were used to develop solar evaporators by surface carbonization and KOH treatment combined with freeze-drying method. Scanning electron microscopy (SEM), solar absorption, solar thermal management and salt dissolution tests showed that the water vapor generation rate of a single column of LV-based solar evaporator after surface carbonization was as high as 3.26 kg m−2 h−1 under 1 sun, and its evaporation efficiency (118%) even exceeded the theoretical valve. After 36 h of continuous use, there was almost no salt deposition. Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), contact angle, thermal conductivity, evaporation enthalpy, and low field nuclear magnetic resonance (LF-NMR) analyses indicated that the high evaporation efficiency of LV-based solar evaporators after surface carbonization was mainly due to high water transport capacity, low water evaporation enthalpy, and high light absorption rate (91%) of LV. The excellent salt-deposition resistance benefitted from the natural multilayered gradient porous structures of LV, forming spontaneous salt backflowing systems. The desalinization rate of LV-based solar evaporators exceeded 99.9%, which was even higher than those of many membrane elements and thermal desalination systems. They also had excellent removal effects on dyes and oily wastewater. After 30 d of continuous soaking, the compressive strength of 2–cm LVs was still 9.4 MPa. KOH-freeze-drying treatment further improved the salt-deposition resistance of LV-based solar evaporators, but reduced their evaporation efficiency and mechanical performance. This work suggests that LVs with carbonized surface have significant potential for development of environmentally friendly biomass solar evaporators with efficient evaporation, excellent resistance to salt deposition, and good durability. • Luffa vine (LV) solar evaporator has high evaporation rate (3.26 kg m−2 h−1) and efficiency (118%). • Natural LV pore structures give the solar evaporator high resistance to salt deposition. • Baking carbonization can make the surface carbon layer and microstructure of LV more stable. • KOH freeze-drying treatment of LV is helpful to improve the salt tolerance of solar evaporator. • The structure of LVs arranged separately help form a cold steamed surface to efficient evaporation. [ABSTRACT FROM AUTHOR]