Abstract By modifying the entangled multi‐degrees of freedom of transition‐metal oxides, interlayer coupling usually produces interfacial phases with unusual functionalities. Herein, a symmetry‐mismatch‐driven interfacial phase transition from paramagnetic to ferromagnetic state is reported. By constructing superlattices using CaRuO 3 and SrTiO 3 , two oxides with different oxygen octahedron networks, the tilting/rotation of oxygen octahedra near interface is tuned dramatically, causing an angle increase from ≈150° to ≈165° for the RuORu bond. This in turn drives the interfacial layer of CaRuO 3 , ≈3 unit cells in thickness, from paramagnetic into ferromagnetic state. The ferromagnetic order is robust, showing the highest Curie temperature of ≈120 K and the largest saturation magnetization of ≈0.7 µ B per formula unit. Density functional theory calculations show that the reduced tilting/rotation of RuO 6 octahedra favors an itinerant ferromagnetic ground state. This work demonstrates an effective phase tuning by coupled octahedral rotations, offering a new approach to explore emergent materials with desired functionalities.
Organic compounds are capable of generating hydroxyl radicals (˙OH) through their excited triplet states in natural water. It is of significance to reveal the underlying mechanism of the generation and obtain the generation quantum yield of ˙OH from organic compounds for better understanding of its involvement in indirect photochemical processes in the environment. In this study, the ˙OH quantum yields (Φ˙OH) of 20 organic compounds were determined by photochemical experiments. The calculated Φ˙OH values for the selected organic compounds vary from (1.2 ± 0.39) × 10-5 to (7.2 ± 0.16) × 10-4. A quantitative structure-activity relationship (QSAR) model for log Φ˙OH was developed and the established model was proven to have a proper goodness of fit, robustness, and predictive ability. The QSAR model was successfully used to predict the Φ˙OH value of organic pollutants. Mechanistic interpretation showed that the electron distribution and the electronegativity of organic compounds are the most important factors that determine the generation of ˙OH. The results are helpful for understanding the generation mechanism of ˙OH from organic compounds and also provide insights into the generation of ˙OH from dissolved organic matter in natural water.
The preventive effects of 29 plant extracts against cucumber powdery mildew were tested with leaf disks method.The results showed that the extracts of Sophora japonica L.,Dalbergia hupeana Hance.,Cucurbita moschata Poiret,and Photinia serrulata Lindl.had a better preventive effect than the other extracts.The effects of these four plant extracts on potted plants in the cultural room were tested respectively.The results showed that the extract of D.hupeana had 72.97 % preventive effect and 91.28 % curative effect against cucumber powdery mildew.The extract of S.japonica had 79.73 % preventive effect and 79.19 % curative effect.Their protective effect against this pathogen both could maintain 12 days after the treatment.The two plant extralts'effects were much better than that of the Triadimefon,a traditional chemical pesticide for controlling this pathogen.
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