In the propagation from meteorological to hydrological drought, there are time-lag and step-abrupt effects, quantified in terms of propagation time and threshold, which play an important role in hydrological drought early warning. However, seasonal drought propagation time and threshold and their dynamics as well as the corresponding driving mechanism remain unknown in a changing environment. To this end, the standardized precipitation index (SPI) and standardized runoff index (SRI) were used respectively to characterize meteorological and hydrological droughts and to determine the optimal propagation time. Then, a seasonal drought propagation framework based on Bayesian network was proposed for calculating the drought propagation threshold with SPI. Finally, the seasonal dynamics and preliminary attribution of propagation characteristics were investigated based on the random forest model and correlation analysis. The results show that 1) relatively short propagation time (less than 9 months) and large propagation threshold (from −3.18 to −1.19) can be observed in the Toxkan River basins (subbasin II), especially for spring, showing low drought resistance; 2) drought propagation time shows an extended trend in most seasons, while the drought propagation threshold displays an increasing trend in autumn and winter in the Aksu River basin (subbasins I–II), and the opposite characteristics in the Hotan and Yarkant River basins (subbasins III–V); and 3) the impacts of precipitation, temperature, potential evapotranspiration, and soil moisture on drought propagation dynamics are inconsistent across subbasins and seasons, noting that reservoirs serve as a buffer to regulate the propagation from meteorological to hydrological droughts. The findings of this study can provide scientific guidelines for watershed hydrological drought early warning and risk management. Significance Statement: The aim of this study is to better understand how the delayed and step-abrupt effects of propagation from meteorological drought to hydrological drought can be characterized through propagation time and threshold. These response indicators determine the resistance of a catchment to hydrological droughts and meteorological droughts. They can help water resources management agencies to mitigate hydrological droughts by taking measures such as water storage, increasing revenue, and reducing expenditure. The findings of this study can provide scientific guidelines for watershed hydrological drought early warning and risk management.

This review surveys strategies in small-molecule emitters that enable tunable emission via tailored through-space interactions (TSIs) and expands to polymeric architectures where strengthened TSIs achieve efficient, full-colour clusteroluminescence.

This review highlights emerging chiral molecular carbon materials for circularly polarized luminescence, emphasizing chirality control, property tuning, integration challenges, and future opportunities in chiroptoelectronic technologies.

High-quality perovskite films with lower defect density are a prerequisite for realizing high-performance perovskite solar cells. However, the inherent soft lattice properties of perovskites often lead to many defects in the final polycrystalline films, severely impairing device efficiency and stability. In this work, an environmentally friendly anti-solvent-assisted strategy is adopted for the preparation of high-quality perovskite films with low defects in an open-air environment through using biodegradable and enriched carboxymethyl cellulose sodium (CMCCNa) as an additive for green anti-solvent ethyl acetate (EA). Through theoretical calculations and experiments, it was found that the strong interactions between CMCCNa and Pb2+ ions not only effectively regulate the film-forming process of perovskites but also effectively passivate various Pb-related defects in the annealed polycrystalline films, resulting in significantly improved photovoltaic performance and device stability. As a result, the CMCCNa treatment device prepared in an open-air environment exhibits significantly improved VOC and FF, with a champion efficiency of 23.13%, compared with the controlled device with a power conversion efficiencies of 21.04%. Meanwhile, the unencapsulated optimized device also exhibits superior storage and light stability over the controlled device.