No abstract

Al-Fe-, Al-Cu-, and Al-Fe-Cu-PILCs were synthesized, characterized and tested in the catalytic wet peroxide oxidation of 4-chlorophenol (4-CP). An apparent induction period followed by a rapid oxidation was observed during the Fenton-like reaction, and the whole reaction could be modeled well using a Fermi's kinetic equation (R 2 = 0.9938~0.9993). The generation of hydroxyl radicals (HO • ) from surface-catalyzed decomposition of H 2 O 2 was the oxidation cause whereas the dissolution of active metals was its result. Accordingly, induction period was the cause of heterogeneous surface activation (catalysis or modification) for more HO • formed by decreasing pH. 4-CP oxidation proceeded via 4-chlorocatechol (major) and hydroquinone (minor) pathways, along the formation of main intermediate (5-chloro-1,2,4-benzentriol). Finally besides CO 2 , H 2 O and Cl − two main compounds (I and II) formed, where the former was identified as 2,4-dioxopentanedioic acid whereas the latter as ferric-oxalate complex. There were marked structural and active differences between Al-Fe-PILC and Al-Cu-PILC in which compared to the latter, the former possessed higher SSA and activity but its optimal calcination temperature was lower and the induction time was also longer. In addition, compound II accounted for a considerable proportion in Al-Fe-PILC system whereas compound I was almost only component in Al-Cu-PILC system.

In recent years, there have been many cases of transformer failures caused by corrosive sulfides. At present, research mainly focuses on the single sulfide dibenzyl disulphide, but few research on multiple sulphur or the oil-paper hybrid insulation. In this study, three typical sulfides dibenzyl disulfide, hexadecyl mercaptan and benzothiophene were selected to form seven sulfide-oil-paper models. Then relaxation calculations were carried out, and through molecular dynamics simulation, the synergistic effect of different sulfides on the properties of insulating paper and insulating oil was discussed. Results show that the coexistence of the three sulfides has the most severe weakening on the mechanical properties of cellulose, and it also causes great damage to hydrogen bonds. Hexadecyl mercaptan has a weaker effect on hydrogen bond destruction, but it will greatly aggravate the cellulose chain movement. The viscosity of insulating oil is generally increased by the influence of sulfide. Hexadecyl mercaptan is the main factor affecting the viscosity. Thiophene has little effect on the viscosity, ctive protection technology on sulphur corrosion.This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

Plant nitrogen (N) uptake is affected by plant–plant interactions, but the mechanisms remain unknown. 15N-labeled technique was used in a pot experiment to analyze the uptake rate of ammonium (NH4+) and nitrate (NO3−) by Abies faxoniana and Picea asperata in single-plant mode, intraspecific and interspecific interactions. The results indicated that the effects of plant–plant interactions on N uptake rate depended on plant species and N forms. P. asperata had a higher N uptake rate of both N forms than A. faxoniana, and both species preferred NO3−. Compared with single-plant mode, intraspecific interaction increased NH4+ uptake for A. faxoniana but reduced that for P. asperata, while it did not change NO3− uptake for two species. The interspecific interaction enhanced N uptake of both N forms for A. faxoniana but did not affect the P. asperata, compared with single-plant mode. NH4+ and NO3− uptake rates for two species were regulated by root N concentration, root nitrate reductase activity, root vigor, soil pH, and soil N availability under plant–plant interactions. Decreased NH4+ uptake rate for P. asperata under intraspecific interaction was induced by lower root N concentration and nitrate reductase activity. The positive effects of interspecific interaction on N uptake for A. faxoniana could be determined mainly by positive rhizosphere effects, such as high soil pH. From the perspective of root-soil interactions, our study provides insight into how plant–plant interactions affect N uptake, which can help to understand species coexistence and biodiversity maintenance in forest ecosystems.