Improving dryland maize productivity and water efficiency with heterotrophic ammonia-oxidizing bacteria via nitrification and cytokinin activity

A two-year field experiment conducted under dryland conditions in semi-humid and drought-prone regions of China aimed to assess the effect of ammonia-oxidizing bacterial on maize water use efficiency and yield.A heterotrophic ammonia-oxidizing bacteria(HAOB)strain S2_8_1 was used.Six treatments were applied:(1)no irrigation+HAOB strain(DI),(2)no irrigation+blank culture medium(DM),(3)no irrigation control(DCK),(4)irrigation+HAOB(WI),(5)irrigation+blank culture medium(WM),and(6)irrigation control(WCK).Results revealed that HAOB treatment increased maize growth,yield,and water use efficiency over controls,regardless of whether the year was wet or dry.This improvement was attributed to the accelerated nitrification in the rhizosphere soil due to HAOB inoculation,which subsequently led to increased levels of leaf cytokinins.Overall,these findings suggest that HAOB inoculation holds promise as a strategy to boost water use efficiency and maize productivity in dryland agriculture.

Large-area fabrication:The next target of perovskite light-emitting diodes

Perovskite materials show exciting potential for light-emitting diodes(LEDs)owing to their intrinsically high photoluminescence efficiency and color purity.The research focusing on perovskite light-emitting diodes(PeLEDs)has experienced an exponential growth in the past six years.The maximum external quantum efficiency of red,green,and blue PeLEDs has surpassed 20%,20%,and 10%,respectively.Nevertheless,the current PeLEDs are still in the laboratory stage,and the key for further development of PeLEDs is large-area fabrication.In this paper,we briefly discuss the similarities and differences between manufacturing high-quality and large-area PeLEDs and perovskite solar cells.Especially,the general technologies for fabricating large-area perovskite films are also introduced.The effect of charge transport layers and electrodes on large-area devices are discussed as well.Most importantly,we summarize the advances of large-area(active area≥30 mm^(2))PeLEDs reported since 2017,and describe the methods for optimizing large-area PeLEDs reported in the literature.Finally,the development perspective of PeLEDs is presented for the goal of highly efficient and large-area PeLED fabrication.It is of great significance for the application of PeLEDs in future display and lighting.

In-situ observation of solid-liquid interface transition during directional solidification of Al-Zn alloy via X-ray imaging

The morphological instability of solid/liquid(S/L)interface during solidification will result in different patterns of microstructure.In this study,two dimension(2 D)and three dimension(3 D)in-situ observation of solid/liquid interfacial morphology transition in Al-Zn alloy during directional solidification were performed via X-ray imaging.Under a condition of increasing temperature gradient(G),the interface transition from dendritic pattern to cellular pattern,and then to planar growth with perturbation was captured.The effect of solidification parameter(the ratio of temperature gradient and growth velocity(v),G/v)on morphological instabilities was investigated and the experimental results were compared to classical"constitutional supercooling"theory.The results indicate that 2 D and 3 D evolution process of S/L interface morphology under the same thermal condition are different.It seems that the S/L interface in 2 D observation is easier to achieve planar growth than that in 3 D,implying higher S/L interface stability in 2 D thin plate samples.This can be explained as the restricted liquid flow under 2 D solidification which is beneficial to S/L interface stability.The in-situ observation in present study can provide coherent dataset for microstructural formation investigation and related model validation during solidification.

Vibration-induced nanoscale friction modulation on piezoelectric materials

Mechanical vibration,as an alternative of application of solid/liquid lubricants,has been an effective means to modulate friction at the macroscale.Recently,atomic force microscopy(AFM)experiments and model simulations also suggest a similar vibration-induced friction reduction effect for nanoscale contact interfaces,although an additional external vibration source is typically needed to excite the system.Here,by introducing a piezoelectric thin film along the contact interface,we demonstrate that friction measured by a conductive AFM probe can be significantly reduced(more than 70%)when an alternating current(AC)voltage is applied.Such real-time friction modulation is achieved owing to the localized nanoscale vibration originating from the intrinsic inverse piezoelectric effect,and is applicable for various material combinations.Assisted by analysis with the Prandtl–Tomlinson(P–T)friction model,our experimental results suggest that there exists an approximately linear correlation between the vibrational amplitude and the relative factor for perturbation of sliding energy corrugation.This work offers a viable strategy for realizing active friction modulation for small-scale interfaces without the need of additional vibration source or global excitation that may adversely impact device functionalities.