Dissolution of metal oxides is fundamentally important for understanding mineral evolution and micromachining oxide functional materials. In general, dissolution of metal oxides is a slow and inefficient chemical reaction. Here, by introducing oxygen deficiencies to modify the surface chemistry of oxides, we can boost the dissolution kinetics of metal oxides in water, as in situ demonstrated in a liquid environmental transmission electron microscope (LETEM). The dissolution rate constant significantly increases by 16-19 orders of magnitude, equivalent to a reduction of 0.97-1.11 eV in activation energy, as compared with the normal dissolution in acid. It is evidenced from the high-resolution TEM imaging, electron energy loss spectra, and first-principle calculations where the dissolution route of metal oxides is dynamically changed by local interoperability between altered water chemistry and surface oxygen deficiencies via electron radiolysis. This discovery inspires the development of a highly efficient electron lithography method for metal oxide films in ecofriendly water, which offers an advanced technique for nanodevice fabrication.

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Previous work has shown that a surface wave on amorphous o-terphenyl (OTP) decays by viscous flow at high temperatures and by surface diffusion at low temperatures. We report that the surface mass transport can be efficiently suppressed by low-concentration polymers. Surface-grating decay has been measured for OTP containing 1 wt % polystyrene (PS, Mw = 1-8 kg/mol), which is miscible with OTP. The additive has no significant effect on the decay kinetics in the viscous-flow regime, but a significant effect in the surface-diffusion regime. In the latter case, surface evolution slows down and becomes nonexponential (decelerating over time). The effect increases with falling temperature and the molecular weight of PS. These results are attributed to the very different mobility of PS (slow) and OTP (fast) and their segregation during surface evolution, and relevant for understanding the surface mobility of multicomponent amorphous materials.

In recent years, multi-rotor unmanned aerial vehicle (UAV) crop protection operations have experienced tremendous growth. Compared with manual operations, they have advantages such as high operational efficiency, small pesticide dosage, and low pesticide hazards for humans. However, the tiny droplets produced during UAV spraying for crop protection are affected by the rotor air flow and will drift in all directions in an uncontrollable manner, severely affecting the pesticide deposition pattern and resulting in pesticide waste. To improve pesticide use efficiency during multi-rotor UAV spraying, an electrostatic spray system was designed based on electrostatic spray technology and a six-rotor UAV. The proper operation parameters for the UAV electrostatic spray were determined by test, which were spray altitude of 50 cm above the crop, spray pressure of 0.3 MPa and charging voltage of 9 kV. Field test was performed based on these parameters. The results showed that compared with non-electrostatic spray, the electrostatic spray improved by 13.6% in the average deposition density above the sampling device and 32.6% in the middle. The research can provide a reference for designing multi-rotor UAV electrostatic spray devices.

Ethanol solutions of diamine, ethylenediamine (EDA) or piperazine (PZ), were found to be able to produce a solid precipitate after the absorption of CO2. The precipitate was identified to be a mixture of monocarbamate and dicarbamate. The details of the reactions between CO2 and diamine were examined. Results show that EDA–ethanol solutions exhibit higher capacity and faster rate for CO2 absorption than PZ–ethanol solutions. As a comparison, the kinetics of CO2 absorption with diamine–water solutions were also tested. It was found that the overall average absorption rate of CO2 in EDA–ethanol solutions is almost double that in EDA–water solutions. Moreover, results show that EDA–carbamate has a decomposition temperature of ∼90 °C and requires a regeneration energy of 25.6% less than traditional monoethanolamine (MEA) solutions, which suggests that EDA–ethanol solutions are promising to be used as cost-effective absorbents for CO2 capture.

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