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Digital elevation models (DEMs) are the fundamental datasets for coastal ecosystem monitoring, and several global open‐accessed DEMs have recently been reported. In coastal regions, a comprehensive vertical accuracy assessment of these DEMs has not yet been carried out. In this study, eight open‐access DEM datasets, including SRTM‐3, SRTM‐1, TanDEM‐X, ASTER GDEM v3, MERIT DEM, AW3D30, NASADEM, and CoastalDEM, were investigated across the coastal region of the Chinese mainland using high accuracy ICESat‐2 data as a reference. Statistical tools including mean absolute error (MAE) and root mean square error (RMSE) were selected to describe the data error/uncertainty and spatial distribution. Moreover, the effects of elevation ranging, slope degree, geomorphogenesis and landuse on vertical accuracy were further analyzed to assess their applicability. The assessment results revealed that the CoastalDEM and NASADEM datasets had the highest accuracy, with MAE values of 1.68 and 1.88 m and RMSE values of 2.55 and 2.61 m, for 3‐arc second and 1‐arc second resolution DEMs, respectively. Other DEMs with close accuracies include AW3D30, SRTM‐1, MERIT, and SRTM‐3 DEM. The results proved that the CoastalDEM outperformed other datasets, indicating its applicability in coastal regions. [ABSTRACT FROM AUTHOR]

Fire is a crucial event regulating the structure and functioning of many ecosystems. Yet few studies have focused on how fire affects taxonomic and functional diversities of soil microbial communities, along with changes in plant communities and soil carbon (C) and nitrogen (N) dynamics. Here, we analyze these effects in a grassland ecosystem 9 months after an experimental fire at the Jasper Ridge Global Change Experiment site in California, USA. Fire altered soil microbial communities considerably, with community assembly process analysis showing that environmental selection pressure was higher in burned sites. However, a small subset of highly connected taxa was able to withstand the disturbance. In addition, fire decreased the relative abundances of most functional genes associated with C degradation and N cycling, implicating a slowdown of microbial processes linked to soil C and N dynamics. In contrast, fire stimulated above‐ and belowground plant growth, likely enhancing plant–microbe competition for soil inorganic N, which was reduced by a factor of about 2. To synthesize those findings, we performed structural equation modeling, which showed that plants but not microbial communities were responsible for significantly higher soil respiration rates in burned sites. Together, our results demonstrate that fire ‘reboots’ the grassland ecosystem by differentially regulating plant and soil microbial communities, leading to significant changes in soil C and N dynamics.Fire significantly increased environmental selection pressure on soil microbial community, where a small subset of highly connected taxa was able to withstand the disturbance. Fire decreased the relative abundances of most functional genes associated with C degradation and N cycling, but stimulated above‐ and belowground plant growth, likely enhancing plant–microbe competition for soil inorganic N. Plants but not microbial communities were responsible for significantly higher soil respiration rates in burned sites. [ABSTRACT FROM AUTHOR]

Nowadays, the droplet–particle collision characteristics in the gas‐phase ethylene polymerization process are still unclear. The high‐speed photography and a quasi‐circle imaging approach are employed to study the collision interaction characteristics between liquid droplets and polyethylene particles. The liquid film evolution is studied through variations of the film thickness on the particle north pole, the dynamic contact angle, center angle and film thickness at the maximum extension. Results have found that for n‐hexane the threshold temperature of the recoil happening increases with increasing initial Weber number, but for 1‐hexene it is stable. Over 70°C evaporation and splash occurs immediately. Under low Weber numbers, the water droplet stays for damping oscillations, the reference stable height of which is linearly related to temperatures. Moreover, three regimes of film thickness variation with time are identified and mathematically described, while Regime 3 characteristics are found strongly dependent on the liquid species, Weber number, and particle temperature. [ABSTRACT FROM AUTHOR]

This paper investigated the influence of 2, 6‐di‐tert‐butyl‐p‐cresol (DBPC) on the long‐term ageing characteristics of oil–paper insulation and the deposition and migration of copper sulphide induced by the reaction of copper and dibenzyl disulphide (DBDS) in oil‐immersed transformers. A thermal ageing experiment at 130°C were designed and conducted by adding different concentrations of DBPC to the naphthenic mineral oil and after the experiments a set of characteristic parameters were tested. The result indicates that the excessive concentration (≥0.6%) of DBPC will slightly increase the ageing of insulating oil and increase the carboxyl group in the mineral oil, affecting the reaction of DBDS and copper, and the insulating paper wrapped on the copper strip was also aged seriously accordingly. Meanwhile, the deposition of copper sulphide on the insulating paper is found to be slightly increased with the increase of the concentration of DBPC. When insulating oil contains DBPC and DBDS, due to migration of DBDS–Cu and DBPC–Cu in oil, the copper ions in the oil would be fluctuating at a certain period of time. Although the addition of a small concentration of DBPC can improve the antioxygenic property of the insulting oil to some extent, the transformers that contain excessive concentration of DBPC may be more harmful than beneficial. [ABSTRACT FROM AUTHOR]

This study investigated the inhibitory effects of adsorption treatment on the degradation of oil–paper insulation and corrosive sulphur in oil. A thermal ageing experiment at 130°C was conducted using five different adsorbents to adsorb some impurities in oil on the 15th day of a 30 day ageing test, the related characteristics of oil–paper insulation before and after the adsorption treatment were measured and analysed. Meanwhile, a thermal ageing experiment at 150°C was also conducted before using five different adsorbents to adsorb dibenzyl disulphide (DBDS) in oil, energy dispersive X‐ray was used to evaluate the degree of the corrosion of windings. The result indicates that adsorption treatment is an effective method to inhibit the degradation of oil–paper insulation. A molecular sieve, silica gel and activated alumina can effectively improve the performance of oil–paper insulation. By contrast, the antioxidant (2, 6‐di‐tert‐butyl‐p‐cresol) can be also adsorbed by adsorbents, which accelerate the ageing degradation of the insulating oil. On the other hand, the adsorbents can adsorb DBDS in oil, but cannot remove all DBDS. The effect achieved from silica gel is especially significant, which not only effectively improves the performance of oil–paper insulation but also adsorbs DBDS in oil. [ABSTRACT FROM AUTHOR]