Search

Air pollution control has become the top priority of China's "green development" concept since 2013. The Chinese government has enacted a range of policies and statutes to control contaminant emissions and improve air quality. On the basis of the national air quality ground observation database, the spatial and temporal distribution of air quality index value (AQI), fine particulate matter (PM2.5), coarse particles (PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), and ozone (O3) were explored in 336 cities throughout China from 2014 to 2019. AQI and most pollutants (except O3) decreased in concentrations from 2014 to 2019. In 2019, all cities except Henan reached the level 2 of the ambient air quality index, and six cities had a lower ambient air quality index and reached the level 1. Spatially, higher pollutant concentrations were concentrated in large city clusters, whereas the areas with high O3 concentration were found across the country. Furthermore, central heating was shown to have a negative impact on air quality. The observed AQI value, PM2.5, PM10, SO2, NO2, and CO concentrations were highest in north and northwest China and Henan province in central China. The correlations among pollutants suggest that the main sources of pollutants are fossil fuel combustion, industrial production, and motor vehicle emissions. The influence of meteorological factors on air quality, long-distance transportation, and the transformations of pollutants should be explored in future research.Supplementary informationThe online version contains supplementary material available at 10.1007/s11869-021-01043-5.

In this paper, the partially crystallized Zr70Cu13.5Ni8.5Al8 bulk metallic glasses (BMGs) were prepared, and their superplastic deformation ability in the supercooled liquid region was studied via compression over a wide range of strain rates from 5 × 10−4 s−1 to 1 × 10−2 s−1. It has been found that the superplastic deformation behavior of the BMGs is strongly dependent on the strain rate and temperature. The flow behavior of the BMGs transformed from Newtonian fluid to non-Newtonian fluid with the increase in the strain rate and the decrease in temperature. Based on the high-temperature compression results, a thermalplastic forming map was constructed, and the optimal superplastic forming parameters were obtained. Then, gears were successfully extruded using part of the optimal thermal processing parameters. Further studies showed that high-temperature extrusion induced the crystallization of the BMGs, which increased the microhardness of the gears. [ABSTRACT FROM AUTHOR]

In this work, a composite photocatalyst consisted of the porous graphitic carbon nitride (pg‐C3N4) nanosheets decorated with in‐situ grown gold (Au) nanoparticles were prepared. By characterizing and analyzing chemical compositions and structures, and optical and electrical properties of this Au/pg‐C3N4 composite, the excellent photocatalytic performance mainly comes from the following aspects: firstly, pg‐C3N4 synthesized from melamine by high‐temperature calcination with the assistance of ascorbic acid has larger specific surface area and narrower band gap width than common g‐C3N4; secondly, localized surface plasmon resonance (LSPR) effect of Au nanoparticles can enhance light absorption of pg‐C3N4 via near‐field enhancement‐induced excitation; thirdly, the heterojunction formed between Au nanoparticles and pg‐C3N4 nanosheets can promote electron transfer. Consequently, Au/pg‐C3N4 presented the obvious improvement of photocatalytic activity on the degradation of rhodamine B and amaranth under simulated solar irradiation that the kinetic rate constant of degradation reaction can be increased by 3.9 and 5.7 times compared with g‐C3N4, respectively. [ABSTRACT FROM AUTHOR]

Obesity presents a significant public health challenge, demanding effective dietary interventions. This study employed a high-fat diet-induced obesity mouse model to explore the impacts of inulin with different polymerization degrees on obesity management. Our analysis reveals that high-degree polymerization inulin (HDI) exhibited a significantly higher oil binding capacity and smaller particle size compared to low-degree polymerization inulin (LDI) ( p  < 0.05). HDI was more effective than LDI in mitigating body weight gain in high-diet induced obese mice, although neither LDI nor HDI affected blood sugar levels when compared to the high-fat diet control group ( p  < 0.05). Both HDI and LDI administrations reduced liver weight and enhanced brown adipose tissue thermogenesis compared to the high-fat diet induced control group ( p  < 0.05). Additionally, HDI suppressed hepatic lipogenesis, resulting in a further reduction in liver triglycerides compared to the high-fat diet-induced obese mice ( p  < 0.05). Notably, HDI improved gut health by enhancing intestinal morphology and modulating gut microbiota structure. HDI administration notably increased the relative abundance of cecal Akkermansia , a gut microbe associated with improved metabolic health, while LDI showed limited efficacy ( p  < 0.05 and p  > 0.05, respectively). These findings underscore the importance of the structural properties of inulin in its potential to combat obesity and highlight the strategic use of inulin with varying polymerization degrees as a promising dietary approach for obesity management, particularly in its influence on gut microbiota composition and hepatic lipid metabolism regulation., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Gan, Zhao, Zhang, Zhao, Li, Jia, Shi, Wang, Guo, Qiao, Cui and Wang.)