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This study analyzed temporal and spatial changes of normalized difference vegetation index (NDVI) on the northern Loess Plateau and their correlation with climatic factors from 1998 to 2012. The possible impacts of human activities on the NDVI changes were also explored. The results showed that (1) the annual maximum NDVI showed an upward trend. The significantly increased NDVI and decreasing severe desertification areas demonstrate that the vegetation condition improved in this area. (2) Over the past decades, climate tended to be warmer and drier. However, the mean temperature significantly decreased and precipitation slightly increased from 1998 to 2012, especially in spring and summer, which was one of the major reasons for the increase in the annual maximum NDVI. Compared to temperature, vegetation was more sensitive to precipitation changes in this area. The NDVI and annual precipitation changes were highly synchronous over the first half of the year, while a 1-month time lag existed between the two variables during the second half of the year. (3) Positive human activities, including the “Grain for Green” program and successful environmental treatments at coal mining bases, were some of the other factors that improved the vegetation condition.

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The combination of ionic liquids with lysozyme has a potential application in food processing and analysis. In this work, at acid conditions, the interaction mechanism of the ionic liquid 1-butyl-3methylimidazolium trifluoromethansulfonate with lysozyme has been investigated by two-dimensional Fourier transform infrared spectroscopy (FTIR). The residues and structures of lysozyme that have preferential interactions with the ionic liquid have been identified. The interaction mechanism can explain experimental results at acidic conditions where it was found that the presence of the ionic liquid is positively correlated to the enhanced enzymatic activity of the hen egg white lysozyme.

Perovskite oxides have been recognized as one of the most attractive oxygen evolution reaction (OER) catalysts because of their low cost, earth abundance, and robust nature. Herein, one-dimensional porous LaFe1–x Ni x O3 (LFNO) perovskite oxide nanofibers (LFNO NFs) are fabricated with a feasible electrospinning route and its further post-calcination treatment. By tailoring the atomic percent of Fe and Ni in the perovskite oxide, we determined that LaFe0.25Ni0.75O3 (LFNO-III) NFs afford the best OER activity among all the prepared perovskite oxides. Especially remarkable is that the further selenide-doped LaFe0.25Ni0.75O3 (LFNOSe-III) NFs exhibit outstanding OER activity with a low overpotential of 287 mV at 10 mA cm–2 and a small Tafel slope of 87 mV dec–1 in 1 M KOH solution, markedly exceeding that of the parent perovskite oxide and the commercial RuO2. It also delivers decent durability with no significant degradation after 22 h of stability test. In the meanwhile, density functional theory calculations are also conducted to justify the optimized adsorption features of *OH, *O, and *OOH intermediates and unveil that the electrocatalytic active sites are the Ni atoms adjacent to Fe in the Ni- and Se codoped perovskite. This work provides an effective method for the development of highly efficient perovskite oxide catalysts.