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In order to study the effect of the cold surface on the anti-frosting performance of the superhydrophobic coating and the impact contact behavior of droplets, a fluorine-based self-assembled superhydrophobic coating was sprayed on the surface of carbon fibers. Subsequently, the frosting, droplet icing and droplet contact behaviors of the sample on a semiconductor refrigeration table were observed visually, and the variation mechanisms of frost formation, droplet icing and droplet impact contact behaviors over time on the surface of superhydrophobic coatings were analyzed. Results showed that unlike ordinary surfaces, condensation droplets on superhydrophobic surfaces did not freeze at-5 ℃. At temperatures of-10,-15 ℃, the frost suppression effect of superhydrophobic surfaces was significantly better than that of ordinary surfaces, with frost formation times delayed by 34 s and 22 s, respectively. Besides, the delayed freezing times of droplets on superhydrophobic surfaces at-5,-10,-15 ℃ were 16 times, 10 times and 9 times longer than those on ordinary surfaces, respectively. The maximum spreading diameter of droplets after colliding with low-temperature superhydrophobic surfaces was the same at different temperatures. The droplet partially rebounded at-5 ℃ and-10 ℃, and rebounded 11 times on the superhydrophobic surface at 25 ℃.

Mass spectrometry is one of the most extensive scientific analysis techniques, which plays an important role in analysis and research of biology, pharmaceutical, chemical industry, new materials and so on. At present, the research method of organic reaction mechanism is mainly through the detection of hypothetical organic reaction intermediates, combined with density functional calculation. Therefore, it is of great significance for mass spectrometer with high sensitivity to analyze and detect the intermediates in organic reactions. In this study, C-C coupling reaction in Suzuki-Miyaura reaction was studied. 3-Bromopyridine, 3-bromoquinoline and 3-bromo-5-phenylpyridine were used to react with phenylboronic acid, 2-methylphenylboric acid and 3,5-dimethylphenylboric acid, respectively, and Pd(PPh3)4 was used as catalyst to carry out one-pot reaction in toluene solvent. During the reaction, the samples were taken at regular intervals, and the intermediates generated after the oxidative addition and transmetalation processes in the Suzuki-Miyaura coupling reaction were detected using electrospray ionization-ion mobility time-of-flight mass spectrometry (ESI-TIMS-TOF MS). The results showed that:1) For the intermediates formed in the oxidative addition process, arylboric acids are not involved in the formation of arylboric acids, the mass-charge ratios observed in the reactions with different arylboric acids are the same. While, the intermediates formed after transfer metallization are different with the two substances involved in the coupling reaction. 2) The isotopic peaks of the detected intermediates are consistent with the predicted spectra. 3) The ion mobility of the detected groups can be detected by TIMS-TOF to distinguish the isomers, and the fragmented small groups can be observed by MS/MS analysis of the detected intermediates. The data of mass-charge ratio, ion mobility and MS/MS obtained by TIMS-TOF are helpful to study organic reaction mechanism, and also can provide a reference for the reaction mechanism catalyzed by metal Pd.

In order to study the freezing process of dynamic water droplets on the surface of anti-icing coatings, a fluorine based self-assembled superhydrophobic coating was prepared on the surface of 7075 aluminum alloy substrate. The variation of the capture rate of dynamic water droplets on the coating surface with the duration of low temperature, surface inclination, and surface temperature was analyzed, and the anti-icing performance of the superhydrophobic coating was further explored. Results showed that the capture rate of water droplets on superhydrophobic surfaces decreased with the prolongation of low temperature duration and the increase of surface inclination angle, and increased with the decrease of surface temperature. At -20 ℃, with a low temperature duration not exceeding 7 min, the superhydrophobic surface could delay the growth rate of ice layers, and the shorter the low temperature duration, the more significant the inhibitory effect of superhydrophobic surfaces on ice layer growth. Besides, in the case of the same duration of low temperature, the smaller the surface inclination, the lower the surface temperature, and the more obvious the inhibitory effect of superhydrophobic surface on ice layer growth.

Baked foods with a huge market scale play an important part in people's daily diet, and the market scale maintains a trend of rapid growth. The quality of baked foods is affected by many factors, such as raw material composition and processing conditions, so understanding the factors affecting the quality of baked foods is of great significance to process and produce high-quality baked foods. This paper reviewed the effects of fermentation conditions, processing conditions, and raw material composition on the quality of baked foods, and it also involved research on functional baked foods with the addition of special nutritional ingredients or low / no sugar content. These new types of baked foods are more in line with the current people's pursuit of the concept of nutritious and healthy diet. This paper could provide the reference for the design and production of high-quality baked foods, and promote the development and upgrading of the baked food industry.