Localized surface plasmon (LSP)-enhanced ultraviolet light-emitting diodes (LEDs) based on a Au/MgO/ZnO metal/insulator/semi- conductor heterostructure were fabricated by embedding Ag nanoparticles (Ag-NPs) into MgO dielectric layer. A ~6-fold electroluminescence (EL) enhancement was achieved from the Ag-NPs decorated device. Time-resolved spectroscopy studies, as well as analogue simulation and theoretical estimation based on experimental data, reveal that the internal quantum efficiency and light extraction efficiency of the heterojunction LED are increased ~3-fold and ~2-fold, respectively, as a result of the introduction of Ag LSPs. This result indicates that the observed EL enhancement originates from a combined effect of both exciton-LSP coupling and photon-LSP coupling.
The Yinma River basin is located in central Jilin Province, China and is the primary source for domestic water and farmland irrigation in the region. Water quality directly affects the ecosystem and public health. With the development of industrial and pharmaceutical plants, aquaculture, and animal husbandry, which are sources of antibiotic pollution, there is increasing discharge into the aquatic environment of the Yinma River basin. To the best of our understanding, there have been no studies on aquatic pollution by antibiotics in this region. Thus, this study investigated the concentration levels and spatial distribution of antibiotics in the water of the Yinma River basin, and evaluated the human health hazards and ecological risks norfloxacin, enrofloxacin, ciprofloxacin, sulfamethoxazole and metronidazole were analyzed in 17 water samples from 13 provincial monitoring sections and 4 state monitoring sections. The results showed that the mean concentration of metronidazole in water was the highest, at 85.21 ng l−1, while enrofloxacin was undetected in all of the samples, and therefore, had the lowest concentration. The total concentrations of the 5 antibiotics ranged from 52.63 ng l−1 to 234.98 ng l−1, with a mean value of 142.06 ng l−1. Spatially, the highest total concentration was observed in the largest residential area, while the lowest total concentration was observed in the largest grassland. The results for hazard quotients suggested that the exposure of water to individual and complex antibiotics from all of the sampling sites posed little to no hazard to human health, but the drinking water pathway significantly contributed to human health hazards; the health hazards to men were higher than those to women. In the Yinma River basin, some sampling sites posed either low or medium risks to the aquatic ecosystem, which are indicated by the levels of individual and complex antibiotics.
Rainfall use efficiency (RUE) is crucial for understanding the changes in grassland productivity due to variations in future rainfall patterns. Recently, numerous studies have been conducted on the relationship between RUE and the amount of rainfall, but there has been little research on the influence of rainfall distribution and the interactive effect of rainfall amounts and distribution on RUE.
Here, a simulated rainfall experiment was conducted to evaluate the impacts of rainfall amount (average rainfall amount (R0), 334 mm; decreased (R‐) and increased (R+) rainfall amounts, 233 mm and 434 mm, respectively) and dry intervals (comprising 6‐day, 9‐day, 12‐day, 15‐day, 18‐day and 21‐day intervals between rainfall) on productivity and RUE in Leymus chinensis (Trin.) Tzvel., a dominant grass of the Eastern Eurasian Steppe.
Our results showed that (1) for biomass production and RUE, moderate extension of dry intervals was conducive to enhancing total biomass production and RUE. The peak values of total biomass and RUE appeared during the 15‐day interval for R‐, and the 18‐day interval for R0 and R+. (2) For biomass allocation, extension of dry intervals decreased the stem to leaf ratio (S/L) and the root to shoot ratio (R/S). (3) Further, the S/L ratio was significantly negatively correlated with RUE.
These results suggest that variations in rainfall patterns can alter the RUE by changing the S/L ratio, and finally influence biomass production in L. chinensis. These findings have important implications for understanding and predicting the effect of future climate change on productivity in semi‐arid grassland.
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