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In order to fully understand the inorganic water-soluble ions and their sources in the atmospheric fine particles PM2.5 in Beijing after coal-to-gas conversion, 41 PM2.5 samples were continuously collected in Haidian District of Beijing during the winter heating period in 2017.The concentrations of 10 kinds of water-soluble ions(Na+, NH4+, K+, Ca2+, Mg2+, F-, Cl-, NO2-, NO3-, SO42-)were analyzed by ion chromatography.The results show that the daily average mass concentration of PM2.5 in Beijing during the sampling period is (94.28±52.49) μg/m3.Compared with the winter of 2016, the average daily PM2.5 concentration in Beijing in 2017 decreased by 29 μg/m3, with a decrease of 28.2%, and the number of pollution days decreased significantly.During the pollution period, NO3-, SO42-, and NH4+in the particulate matter were significantly higher than the clean period.The ratio of the concentration of ρ(NO3-)/ρ(SO42-) is greater than 1, and the contribution of the mobile source is relatively large, reflecting that the implementation of the "coal to gas" policy has contributed to the reduction of sulfate emissions from fixed sources such as coal.Time-of-flight secondary ion mass spectrometry(TOF-SIMS) was combined with mass high resolution mode and positive and negative ion imaging mode to characterize PM2.5.The results show that NH4+tends to exist in the form of molecular ammonium sulfate or ammonium hydrogen sulfate during the pollution period.

The impact of the active site produced by the active metal V centre on the production of phenol from benzene was deduced from the cluster model structure of VAPO-5. In this work, the mechanism of benzene to phenol under the VAPO-5 model was explored. The transition states, intermediates, and reaction energy barrier throughout the reaction were evaluated by the ONIOM approach, which combines semi-empirical analysis with density functional theory. The outcomes demonstrated that this reaction was divided into four stages, with each stage's energy barriers being 59.9, 122, 204.8, and 60.7 kJ/mol, respectively. And a lower energy barrier of 204.8 kJ/mol must be surpassed to pass the determining speed phase's energy barrier of 296.8 kJ/mol. Additionally, the solvation of acetonitrile was looked into, resulting in the crossing of the energy barrier of 174.8 kJ/mol. [ABSTRACT FROM AUTHOR]

In order to investigate the effect of aluminum nitride (AlN) on the self‐cleaning and bouncing properties of room temperature vulcanized (RTV) silicone rubber, a superhydrophobic AlN/RTV composite with micro‐nano structure was prepared by powder scattering technology. The method combines the characteristics of RTV curing at room temperature, and has the advantages of simple operation, low cost and easy realization. Bouncing experiments, with different droplet sizes, different tilting angles and different temperatures, and self‐cleaning experiments were designed. The micro‐morphology of superhydrophobic surface was analyzed by Raman spectroscopy, scanning electron microscope, energy dispersive spectrometer, and interferometric 3D profilometer. The results show that the static contact angle and the rolling angle of AlN/RTV are 157.7 ± 0. 9° and 4.2 ± 0.7°, respectively. Many micro‐roughness structures were formed on the RTV surface by AlN, which reduced the contact area between droplets and the sample surface, so the samples had outstanding self‐cleaning and bouncing properties. [ABSTRACT FROM AUTHOR]

Silicone rubber materials have excellent comprehensive properties and are widely used in outdoor insulation, aerospace, and other fields. Due to its low surface energy and the appearance of biomimetic superhydrophobic materials, silicone rubber has become one of the popular materials in the field of superhydrophobicity. Superhydrophobic silicone rubber materials play an irreplaceable role in a wide range of applications such as long‐distance high‐voltage power transmission and high‐speed rail transportation. In this paper, research on superhydrophobic materials, including typical fabrication methods, is summarized to provide an overview of the up‐to‐date research state and progress in detail. [ABSTRACT FROM AUTHOR]